OA16382A - Sub headlight unit and sub headlight system for use in vehicle that leans into turns, and vehicle that leans into turns. - Google Patents

Abstract

A headlight unit for use in a vehicle that leans into turn includes a headlight light source. When the vehicle is in an uprght state, an illumination range of the headlight light source is partially or entirely contained in one side of the vehicle with respect to a width direction of the vehicle. The brightness of the headlight light source changes in accordance with a lean angle of the vehicle. When the lean angle of the vehicle leaning to the one side with respect to the width direction of the vehicle takes a reference value that is set for the headlight source, the headlight light source lights up with a first brightness, and when the lean angle of the vehicle changes from the reference value to an upper value that is greater than the reference value, the brightness of the headlight light source changes from the first brightness to a second brightness that is higher than the first brightness.

Description

SUB HEADLIGHT UNIT AND SUB HEADLIGHT SYSTEM FOR USE IN VEHICLE TI IAT LEANS INTO TURNS, AND VEHICLE THAT LEANS INTO TURNS [0001]

The présent invention relates to a sub headlight unit and a sub headlight system for use in a vehicle that leans into turns, and to a vehicle that leans into turns.

[0002]

In general, in a vehicle that leans into turns (such as saddle-ride type vehicles including motorcycles, three-wheeled motor vehicles, snowmobiles, and ATVs (ail terrain vehicles)), when the vehicle corners or turns at an intersection, a rider opérâtes a handlebar and additionaily shifts his/her own weight in order to counteract centrifugal force acting on a vehicle body. Thereby, the vehicle turns with an attitude (hereinafter, also referred to as “lean attitude”) ieaning to the inner side of a curve. On the other hand, in a vehicle that does not lean into turns, for example, in an automobile, when the vehicle corners or turns at an intersection, a rider opérâtes a steering wheel and turns with centrifugal force acting on a vehicle body. Therefore, în the vehicle that does not lean into turns, the vehicle body leans to the outer side of a curve due to the centrifugal force.

[0003]

In the vehicle that leans into turns, the turning is made with an active use of the weight shifting of the rider himself/herself. Therefore, the vehicle body largely leans. In the vehicle that does not lean into turns, the vehicle body leans to the outer side of the curve due to the centrifugal force. The degree of this Ieaning varies depending on the running speed of the vehicle and the magnitude (radius) of the curve, and this Ieaning of the vehicle body is not utilized for the turning. In the vehicle that does not lean into turns, it is préférable that the amount of ieaning to the outer side of the curve due to the centrifugal force is small.

[0004]

Thus, at a time of cornering or turning at an intersection, the vehicle that leans into turns causes the vehicle body to lean to the inner side of the curve with a relatively large amount of Ieaning, while the vehicle that does not lean into turns causes the vehicle body to lean to the outer side of the curve with a relatively small amount of Ieaning.

[0005]

Normally, a vehicle is provided with a plurality of lights irrespective of whether or not the vehicle leans into turns. The lights include a light intended mainly to ensure a field of view of a rider ofthe vehicle and a light intended mainly to enable a surrounding vehicle or the like to recognize the presence of the own vehicle. A headlight is the light intended mainly to ensure the field of view of the rider of the vehicle, and in general, is configured to switcli between a

Formatted: Left: 2,5 cm, Right: 2 cm, Top: 2 cm, Bottom: 2 cm

high beam (running headlight) and a low beam (passing headlight).

[0006]

The high beam, which emits light in a horizontal (npward) direction, ensures a field of view at a long distance. Generally, in order to avoid dazzling a rider of a surrounding vehicle, the high beam is used in a situation where there is no vehicle or the like existing ahead at night. The low beam, which emits light in a downward direction, is used even in a situation where there is a vehicle or the like existing ahead. Therefore, în a normal case, a vehicle often runs with the low beam turned on.

[0007]

When the vehicle that leans into turns is running on a straight road, an illumination range of a headlight light source (low beam) spreads evenly to the left and right in an area ahead in an advancing direction and below a horizontal plane including the headlight light source. When the vehicle that leans into turns is running on a road curving to the left, the vehicle runs with the vehicle body inclined to the left. Accordingly, the illumination range of the headlight light source spreads downward to the left. As a resuit, a nearer position on a running lane is illuminated. Thus, the illumination range in an area inside the curve and ahead in the advancing direction is reduced.

[0008]

Therefore, a vehicle has been proposed in which, in addition to a main headlight that illuminâtes an area ahead of the vehicle, a pair of right and left sub headlights that are turned on dependîng on the magnitude of a lean angle (angle of inclination of a vehicle body to the inner side of a curve relative to an upright state thereof) are provided as the headlight (WO 2010/061651). Each of the sub headlights includes two light sources (filaments). In the vehicle disclosed in WO 2010/061651, when the lean angle increases and reaches a predetermined value, one of the two light sources included in the sub headlight is turned on. When the lean angle further increases and reaches a predetermined value, the two light sources are turned on.

[0009]

Such a vehicle is known front WO 2010/061651.

[0010]

A situation where the vehicle corners or turns at an intersection îs not always the same, and there are a widc variety of running scenes. The présent inventors hâve studied cases where the vehicle disclosed in WO 2010/061651 runs in a wide variety of scenes, and found out the following problème.

[0011]

In the vehicle disclosed in WO 2010/061651, when the vehicle corners or turns at an intersection, the illumination range of the sub headlight within a rider’s field of view largely

changes, which sometimes causes the rider to feel unconifortable.

[0012]

For exampie, even on a road having a curve with the same radius, sonie vehicles pass through the curve at a relatively low speed, and other vehicles pass through the curve at a relatively high speed. At this tinie, the lean angle of the vehicle passing at the high speed is changed more rapidly than the lean angle of the vehicle passing at the low speed. That is, even though a vehicle passes through a road having a curve with the same radius, the amount of change in the lean angle per unit time varies depending on the vehicle speed.

[0013]

Furthermore, even when the vehicle is running at the same speed, the lean angle is gently changed in a curve with a large radius while the lean angle is rapidly changed in a curve with a small radius. Accordingly, for example, in a case of continuously passing through a pluraiity of curves having different radii during touring on a mountain road, the amount of change in the lean angle per unit time changes in each curve, even though the speed does not change so much.

[0014]

In the vehicle disclosed in WO 2010/061651, the two light sources of the sub headlight are sequentially turned on in accordance with an increase in the lean angle. Accordingly, at a time point when a light source is turned on, an illumination range of this light source is additionaliy provided, which can suppress a réduction in the illumination range which may be caused by inclination of the vehicle.

Here, in accordance with an increase in the lean angle of the vehicle, an illumination range of a sub headlight produced on a road surface continuously approaches to the vehicle, and accordingly a cut-off line of the sub headlight also approaches to the vehicle. The speed of movement of the cut-off line of the sub headlight light source varies depending on the amount of change in the lean angle per unit time. In other words, the speed of movement of the cut-off line varies depending on a running scene.

Therefore, in a case where the speed of movement of the cut-off line iargely changes upon each turn in a curve or in a case where the speed of movement of the cut-off line increases, the rider may feel unconifortable.

[00'5]

The présent invention has been made in view of the problems described above, and an object of the présent invention is to prevent a rider from feeling unconifortable about a change in an illumination range In the course of an increase or decrease in the lean angle of a vehicle body.

[0016]

To solve the problems described above, the présent invention adopts the following configurations.

( 1 ) A sub headlight unit for use in a vehicle that leans into tums, wherein the sub headlight unit includes a sub headlight light source that illuminâtes, at one side with respect to a width direction of the vehicle, an area ahead and outward of the vehicle with respect to the width direction of the vehicle, the brighlness of the sub headlight light source changes in accordance with a lean angle ofthe vehicle, when the lean angle of the vehicle leaning to the one side with respect to the width direction of the vehicle reaches a reference value that is set for the sub headlight light source, the sub headlight light source lights up wïtli a first brightness, and in a period from when the lean angle of the vehicle reaches a lower value that is less than the reference value lo when the lean angle of the vehicle reaches the reference value, the sub headlight light source lights up with a brightness lower than the first brightness.

[0017]

In a state where a main headlight light source or a sub headlight light source (hereinafter also referred to as a first headlight light source) included in the vehicle has been already turned on, when the lean angle increases, an illumination range produced on a road surface is reduced so that a cut-off line of the first headlight light source that has been already turned on approaches to the vehicle. Therefore, the illumination range of the first headlight light source gradually moves away from a position a rider desires to see toward the vehicle.

In a configuration of (1), under such a situation, at a time point when the lean angle reaches the lower value that is less than the reference value before the lean angle reaches the reference value of a second sub headlight light source thaï will bc turned on next, the second sub headlight light source lights up with a brightness lower than the first brightness. As a resuit, an illumination range of the second sub headlight light source that is currently turned on partially overlaps the cut-off line of the first headlight light source that has been previousiy turned on. Here, the brightness of the second sub headlight light source is lower than the first brightness. Therefore, a situation where the turn-on of the second sub headlight makes the rider feel uncomfortable is suppressed.

Then, along with an increase in the lean angle, the illumination range of the first headlight light source is reduced so that the cut-off line approaches to the vehicle, and when the lean angle reaches the reference value that is set for the second headlight light source, the second headlight light source lights up with the first brightness. Accordingly, when the illumination range ofthe first headlight light source is moving away from the position the rider desires to see, the illumination range of the second headlight light source can spread over the position the rider desires to see.

As a resuit, the cut-off line of the second headlight light source is ntore conspicuous lo the rider than the cut-off line of the first headlight light source. An illumination range having a

predetermined illuminance is enlarged along with an increase în the brightness of the second headlight light source from the brightness lower than the first brightness to the first brightness. Therefore, an effect of reducing the speed of approach of the cut-off line to the vehicle is exerted. Since the effect of reducing the speed of movement of the cut-off line is exerted, a change in the speed of movement of the cut-off line which occurs in each turn can be made small. This enables suppression of an uncomfortable feeling, which may otherwise be given to the rider.

Since a réduction in the illumination range of the headlight is suppressed, occurrence of a situation where the position the rider desires to see is not sufFiciently covered by the illumination range of the headlight can be suppressed. This enables suppression of an uncomfortable feeltng, which may otherwise be given to the rider.

[0018]

Here, in order to suppress the speed of movement of the cut-off line, it is conceivable to gradually increase the brightness of the headlight light source in accordance with a length of time having elapsed since the lean angle reached the reference value. In this case, however, a change in the brightness of the headlight light source is linked to time. Accordingly, the responsiveness to a change in the lean angle decreases, and there is a risk that a time period may occur during which the position the rider desires to see is not coïncident with the illumination range of the headlight.

In this respect, in the configuration of(l), the brightness ofthe headlight light source changes in accordance with the lean angle of the vehicle. This can reduce a change in the speed of movement ofthe cut-off line which occurs in each turn while ensuring the responsiveness to a change in the lean angle. This also enables suppression of occurrence of a time period during which the position the rider desires to see is not sufficiently covered by the illumination range of the headlight.

[0019] (2) The sub headlight unit according to (l), wherein when the lean angle of the vehicle reaches the lower value that is set for the sub headlight light source, an illumination range of the sub headlight light source contains a space above a horizontal line, when the lean angle of the vehicle reaches the reference value that is set for the sub headlight light source, the illumination range of the sub headlight light source is located in a space below the horizontal line.

[0020] ln a configuration of (2), when the lean angle of the vehicle reaches the reference value so that the sub headlight light source lights up with the first brightness, the illumination range of the sub headlight light source is located in a space below the horizontal line. Accordingly, occurrence of glare can be suppressed. When the lean angle reaches the lower value, the illumination range of the sub headlight light source contains a space above the horizontal line. However, the sub headlight light source lights up with a brigbtness lower than the first brightness, and therefore occurrence of glare can be suppressed.

[0021] (3) The sub headlight unit according to ( 1 ) or (2), wherein a cut-off line of the sub headlight light source obtained when the lean angle of the vehicle reaches the reference value that is set for the sub headlight light source is doser to horizontal than the cut-off line of the sub headlight tight source obtained when the lean angle of the vehicle reaches the lower value that is set for the sub headlight light source.

[0022] )n a configuration of (3), when the lean angle reaches the reference value, the cut-off line of the sub headlight light source is close to horizontal. Accordingly, when the headlight light source lights up with the first brightness, a wide illumination range can be ensured on a road surface, with prévention of glare.

[0023] (4) The sub headlight unit according to any one of ( 1 ) to (3), wherein the sub headlight light source comprises a plurality of the sub headlight light sources, the reference value and the lower value are individuatly set for each of the sub headlight light sources.

[0024]

In a configuration of (4), along with an increase in the lean angle, the sub headlight light sources, sequentially from the one having the smallest reference value set therefor, lights up with the brightness lower than the first brightness and then lights up with the first brightness. Sequentially changing the brightness of each sub headlight light source in this manner can slow the speed of movement ofthe cut-off line while suppressinga réduction in the illumination range of the sub headlight light source in accordance with the increase in the lean angle.

[0025] (5) The sub headlight unit according to (4), wherein the reference value of one sub headlight light source is equal to or smaller than the lower value of another sub headlight light source for which the next greatest reference value after that ofthe one sub headlight light source is set.

[0026]

There is the upper limit in an output of the headlight light source, and energy such as fuel loaded on the vehicle is also limited. Therefore, it is préférable to make effective use of the headlight light source based on the relationship between the energy efficiency and the illumination range. Even if the second headlight light source lights up with a brightness lower than the first brightness before the first headlight light source lights up with the first brightness, it

is difficult to fully enjoy the advantage of compensation of the illumination range by the second headlight light source, because the brightncss of the first headlight light source will be subsequently increased. Therefore, in a configuration of (5), in the course of an increase in the lean angle, the second headlight light source is caused to light up with a brightness lower than the first brightness after the first headlight light source lights up with the first brightness. This allows ail effective use of the respective headlight light sources.

Here, the first headlight light source means such a headlight lîglit source that the reference value of the lean angle set therefor is the first to be reached in the course of the lean angle increasing and reaching the reference value of the headlight light source. The second headlight light source means such a headlight light source that the reference value of the lean angle set therefor is the next to be reached after the reference value of the first headlight light source is reached.

[0027] (6) The sub headlight unit according to any one of (l) to (5), wherein an optical axis of the sub headlight light source is fixed, the sub headlight light source whose optical axis is fixed lights up with the first brightness when the lean angle of the vehicle reaches the reference value that is set for the sub headlight light source, and lights up with a brightness lower than the first brightness in the period from when the lean angle of the vehicle reaches the lower value that is less than the reference value to when the lean angle of the vehicle reaches the reference value.

[0028]

In order to suppress the speed of movement of the cut-off line, it is conceivable to provide a movable mechanism and a movable member for physically changing the orientation of the light source and to controi the movable mechanism and the movable member in accordance with an increase in the lean angle, thereby adjusting the orientation of the light source. However, to provide the movable mechanism and the movable member, it is necessary that a space for them is ensured in the vehicle. Therefore, this method is not suitable for a relatively small vehicle.

In this respect, in a configuration of (6), the optical axis of the headlight light source is fixed. Therefore, any movable mechanism and any movable member for moving the optical axis of the headlight light source are not required. This enables avoidance of an increase in the size of the sub headlight unit.

[0029] (7) A sub headlight system for use in a vehicle that leans into turns, the sub headlight system including:

the sub headlight unit according to any one of ( 1 ) to (6);

a control part that changes the brightness of the sub headlight light source in accordance with the lean angle of the vehicle; and a détection part that detects a variable available for obtaining the lean angle of the vehicle, wherein, when the lean angle of the vehicle leaning to the one side with respect to the width direction of the vehicle reaches the reference value that is set for the sub headlight light source, the control part causes the sub headlight light source to light up with the first brightness, and in the period from when the lean angle of the vehicle reaches the lower value that is less than the reference value to when the lean angle of the vehicle reaches the reference value, the control part causes the sub headlight light source to light up with a brightness lower than the first brightness.

[0030]

In a configuration of (7), an AFS (Adaptive Front-Lighting System) is acliieved that enables suppression of occurrence of a situation where the rider feels uncomfortable about a change in the illumination range.

[0031] (8) The sub headlight system according to (7), wherein the sub headlight system includes a voltage detector that detects a supply voltage value of a voltage that is supplied from a battery provided in the vehicle to the sub headlight light source, the control part performs:

a comparison process for comparing the supply voltage value detected by the voltage detector against a reference voltage value of the battery; and an adjustment process for adjusting, based on a resuit of the comparison, the brightness of the sub headlight light source that changes in accordance with the lean angle of the vehicle.

[0032]

A configuration of (8) can suppress a change in the illumination range of the sub headlight light source which is caused by a variation in the supply voltage supplied from the battery to the sub headlight light source. Accordingly, occurrence of glare can be suppressed.

[0033]

The présent invention can also adopt the following configurations.

(8-1) The sub headlight system according to (7), wherein the sub headlight system includes a température detector that detects the température of the sub headlight light source or the vicinity of the sub headlight light source, the control part performs an adjustment process for adjusting, based on the température detected by the température detector, the brightness of the sub headlight light source that changes in accordance with the lean angle of the vehicle.

ΙΟ [0034]

A configuration of (8-1) can correct a réduction in the brighlness of the sub headlight light source (for example, an LED) caused by a température rise.

[0035] (8-2) The sub headlight system according to (7), wherein the control part perforais:

a distance information acquisition process for acquiring distance information indicating a distance the vehicle has traveied; and an adjustment process for adjusting, based on the distance information acquired in the distance information acquisition process, the briglitness of the sub headlight liglit source that changes in accordance with the Jean angle of the vehicle.

[0036] (8-3) The sub headlight system according to (7), wherein the control part perforais:

a time information acquisition process for acquiring time information indicating a period of use of the vehicle or the sub headlight light source; and an adjustment process for adjusting, based on the time in formation acquired in the time information acquisition process, the briglitness of the sub headlight light source tliat changes in accordance with the lean angle of the vehicle.

[0037]

A configuration of (8-2) or (8-3) can correct a réduction in the brighlness of the sub headlight light source caused by a long-term use.

[0038] (9) The sub headlight system according to (8), wherein when the lean angle of the vehicle is in a range of at least the lower value and less than the reference value, the control part perforais the adjustment process, while when the lean angle of the vehicle is out of the range, the control part does not perforai the adjustment process.

[0039]

In a configuration of (9), when the lean angle of the vehicle is out of lhe range, the adjustment process is not performed. Accordingly, at a time of causing the sub headlight light source to light up with a relatively high output in accordance with the lean angle, the output can be made without limitation because the adjustment process is not performed. Therefore, a wide illumination range can be ensured.

[0040]

The configuration of (9) is also adoptable in the sub headlight system according to any one of (8-1) to (8-3) described above.

[0041]

ΙΟ (ΙΟ) A vehicle that leans into turns, the vehicle including the system according to any one of (7) to (9).

[0042]

A configuration of (10) enables suppression of occurrence of a situation where the rider feeis uncomfortable about a change in the illumination range.

[0043] (l l) A method to control a sub headlight unit for use in a vehicle that leans into turns, with a sub headlight light source, wherein the sub headlight light source illuminâtes, at one side with respect to a width direction of the vehicle, an area ahead and outward of the vehicle with respect to the width direction of the vehicle, the brightness of the sub headlight light source changes in accordance with a lean angle of the vehicle, when the lean angle of the vehicle leaning to the one side with respect to the width direction of the vehicle reaches a reference value that is set for the sub headlight light source, the sub headlight light source lights up with a first brightness, and in a period front when the lean angle of the vehicle reaches a lower value that is less than the reference value to when the lean angle of the vehicle reaches the reference value, the sub headlight light source lights up with a brightness lower than the first brightness.

[0044] (12) A method to control a sub headlight unit for use in a vehicle that leans into turns, with a sub headlight light source according to ( 11 ), wherein when the lean angle of the vehicle reaches the lower value that is set for the sub headlight light source, an illumination range of the sub headlight light source contains a space above a horizontal line, when the lean angle of the vehicle reaches the reference value that is set for the sub headlight light source, the illumination range of the sub headlight light source is located in a space below the horizontal line.

[0045] (13) A method to control a sub headlight unit for use in a vehicle that leans into turns, with a sub headlight light source according to ( 12), wherein a cut-off line of the sub headlight light source obtained when the lean angle of the vehicle reaches the reference value that is set for the sub headlight light source is doser to horizontal than the cut-off line of the sub headlight light source obtained when the lean angle of the vehicle reaches the lower value that is set for the sub headlight light source.

[0046] (14) A method to control a sub headlight unit for use in a vehicle that leans into turns, with a sub headlight light source according to ( 13), wherein

II the reference value and the lower value are individually set for each of a plurality of sub headlight light sources, the reference value of one sub headlight light source is equal to or smaller than the lower value of another sub headlight light source for which the next greatest reference value after that of the one sub headlight light source is set.

[0047] (15) A method to control a sub headlight unit for use in a vehicle thaï leans into tums, with a sub headlight light source according to (14), wherein an optica) axis of the sub headlight light source is fixed, the sub headlight light source whose optical axis is fixed lights up with the first brightness when the lean angle of the vehicle reaches the reference value tliat is set for the sub headlight light source, and lights up with a brightness lower than the first brightness in the period front when the lean angle of the vehicle reaches the lower value that is less than the reference value to when the lean angle of the vehicle reaches the reference value, [0048]

Here, in the présent invention, the optical axis is a straight line tliat passes through a light source and the center of a maximum illuminance portion of ernîtted light. The center of the maximum illuminance portion of the emitted light can be identified by emitting light from a light source to a screen that is piaced alicad of the light source. This screen illuminance test can be implemented by a method specified in J1S D16I9. Also, the cut-off line and the illumination range having the predetermined illuminance can be identified based on a resuit (such as an isolux distribution map) of the screen illuminance test mentioned above. In the présent invention, the illumination range means an illumination range having a predetermined illuminance, and this predetermined illuminance is not particularly limited. The cul-off line and the illumination range having the predetermined illuminance in a plan view can be identified based on a roadsurface light distribution that is obtained by converting the resuit ofthe screen illuminance test mentioned above into the road-surface light distribution. The conversion into the road-surface light distribution can be implemented by a conventionally known method. To be spécifie, through commonly-used drawing and géométrie calculation, conversion from a screen illuminance value into a road-surface illuminance value can be performed. In such a case, the following expression (I) is usable. In the following expression (I), D represents a light source, E represents a point on a road surface, and F represents a point of intersection at which the screen piaced between D and E intersects with a straight line connecting D to E.

Road-surface illuminance (Lx) = Screen llluminance (Lx) * [(Distance between D and F (m)) ! (Distance between D and E (m))]² ... (I) [0049]

These and other objects, features, aspects and advantages of the présent invention will

Ι2 become apparent to those skilled in the art front the following detailed description, which, taken in conjunction with the accompanying drawings, discloses some embodiments of the présent invention.

[0050]

The présent invention enables suppression of occurrence of a situation where a rider feels uncomfortable about a change in an illumination range.

[0051] [FIG. 1] A front elevationai view schematically showing a motorcycle according to a first embodiment of the présent invention.

[FIG. 2] A block diagram showing a basic configuration concerning sub headlight light sources of the motorcycle shown in FIG. 1.

[FIG. 3] A front elevationai view schematically showing optical axes and cut-off lines of the sub headlight light sources of the motorcycle in an upright state.

[FIG. 4] A chart showing the relationship between a lean angle of the motorcycle and the brightnesses of the sub headlight light sources according to the first embodiment of the présent invention.

[FIG. 5] (a) is a diagrani schematically showing a screen light distribution obtained when the lean angle of the motorcycle takes a value that is in the range from a lower value Tt to a reference value Kj and is relatively close to the lower value Tj; (b) is a diagram schematically showing a screen light distribution obtained when the lean angle ofthe motorcycle takes a value that is in the range from the lower value T, to the reference value K, and is greater than the lean angle shown in (a); and (c) is a diagram schematically showing a screen light distribution obtained when the lean angle ofthe motorcycle takes the reference value Kj.

[FIG. 6] (a) is a diagram schematically showing a screen light distribution obtained when the lean angle of the motorcycle takes an upper value LJ g (b) is a diagram schematically showing a screen light distribution obtained when the lean angle of the motorcycle takes a value that is in the range from a lower value T₂ to a reference value K₂; and (c) is a diagrani schematically showing a screen light distribution obtained when the lean angle of the motorcycle takes the reference value K₂.

[FIG. 7] (a) is a diagram schematically showing a screen light distribution obtained when the lean angle ofthe motorcycle takes a value that is in the range from a lower value T₃ to a reference value K₃; and (b) is a diagram schematically showing a screen light distribution obtained when the lean angle of the motorcycle takes the reference value K₃.

[FIG. 8] A diagram illustrating a light distribution, schematically showing an illumination range of a headlight produced on a road surface at a time when the lean angle of the motorcycle takes a value that is in tlte range from the lower value T| to the reference value K| and is relatively close to the lower value T|.

(fi

I ι

[FIG. 9] A diagram illustrating a light distribution, schematically showing an illumination range of the headlight produced on a road surface at a time when the lean angle of the motorcycle takes a value that is in the range from the lower value Ti to the reference value Ki and is greater than the lean angle shown in FIG. 8.

[FIG. 10] A diagram illustrating a light distribution, schematically showing an illumination range of the headlight produced on a road surface at a time when the lean angle of the motorcycle lakes the reference value K|.

[FIG. Il] A diagram illustrating a light distribution, schematically showing an illumination range of the headlight produced on a road surface at a time when the lean angle of the motorcycle lakes the upper value Ut.

[FIG. 12] A diagram illustrating a light distribution, schematically showing an illumination range of the headlight produced on a road surface at a time when the lean angle of the motorcycle takes a value that is in the range from the lower value T₂ to the reference value K₂.

[FIG. 13] A diagram illustrating a light distribution, schematically showing an illumination range of the headlight produced on a road surface at a time when the lean angle of the motorcycle takes the reference value K₂.

[FIG. 14] A diagram illustrating a light distribution, schematically showing an illumination range of the headlight produced on a road surface at a time when the lean angle of the motorcycle takes an upper value U₂.

[FIG. 15] A diagram illustrating a light distribution, schematically showing an illumination range of the headlight produced on a road surface at a time when the lean angle of the motorcycle takes a value that is in the range from the lower value T3 to the reference value K₃.

[FIG. 16] A diagram illustrating a light distribution, schematically showing an illumination range of the headlight produced on a road surface at a time when the lean angle of the motorcycle takes the référencé value K3.

[FIG. 17] A diagram illustrating a light distribution, schematically showing an illumination range of the headlight produced on a road surface at a time when the lean angle of the motorcycle takes the upper value U₃.

[FIG. 18] A diagram showing the relationship between the lean angle of the motorcycle and an illumination distance of the headlight illuminating a path of the motorcycle according to the first embodiment of the présent invention.

[FIG. 19] A chart showing the relationship between the lean angle of the motorcycle and the brightnesses of the sub headlight light sources according to a second embodiment of the présent invention.

[FIG. 20] A diagram showing the relationship between the lean angle of the

I4 motorcycle and the illumination distance of the headlight illuminating a path of the motorcycle according to the second embodiment of the présent invention.

[0052] <First Embodiment>

FIG. I is a front elevational view schematicaily showîng a motorcycle according to a first embodiment of the présent invention.

A motorcycle I0 is an example of a vehicle that leans into turns according to the présent invention. In the présent invention, no particular limitation is put on the vehicle that leans into turns. For example, saddle-ride type vehicles including motorcycles, three-wheeled motor vehicles, snowmobiles, and ATVs (ail terrain velucles) may be mentioned. In the following description, the terms “front and “back are terms with respect to an advancing direction of the vehicle, the terms “up” and “down are terms with respect to the vertical direction of the vehicle, and the terms “right” and “left” are terms with respect to a rider.

[0053]

The motorcycle 10 includes a handlebar I2. An operation switch 15 is provided in a left portion of the handlebar I2 with respect to a width direction of the vehicle. The operation switch 15 includes a beam switch I5B and a flasher switch 15F (see FIG. 2). A steering shaft (not shown) is fixed to a center portion ofthe handlebar 12 with respect to the width direction of the vehicle. The steering shaft extends downward through a headpipe (not shown). A frontfork I7 is provided at a lower end of the steering shaft. A front wheel 16 is rotatabiy supported at the lower end of the frontfork I7. The headpipe is a member constituting a vehicle body frame. In the présent invention, no particular limitation is put on the vehicle body frame, and a conventionally known configuration ts adoptable.

[0054]

A front cover I8 covers a front part of the headpipe having the steering shaft passing therethrough. On a front surface of the front cover 18, a main headlight 11 is provided in a center portion with respect to the width direction of the vehicle. The main headlight 11 includes a high beam light source l IH (running headlight) and a low beam light source I IL (passing headlight). The high beam light source 11 II illuminâtes an area ahead of the motorcycle 10 at a height equal to or above a horizontal plane ofthe main headlight 11. The low beam light source l IL illuminâtes an area aliead of the motorcycle 10 at a height below the horizontal plane ofthe main headlight 11.

[0055]

The high beam light source 11H and the low beam light source 11L are configured such that only one of them is turned on in accordance with an operation performed on the beam switch 15B (see FIG. 2) by the rider.

[0056]

*L 'v

X

The motorcycle 10 includes a sub headlight 13. The sub headlight I3 is coniposed of two sub headlight units 13L and I3R of variable light distribution type. Each of the sub headlight units I3L and I3R is provided at each side with respect to the width direction of the vehicle. The sub headlight unit Ï3L includes a plurality of sub headlight light sources l3La, l3Lb, and !3Lc. The sub headlight light sources !3La, !3Lb, and l3Lc are arranged in this order from the center toward the upper left with respect to the width direction of the vehicle. The sub headlight light sources l3La, l3Lb, and !3Lc illuminate an area ahead and left-lateral with respect to the width direction of the vehicle. Illumination ranges of the sub headlight light sources l3La, I3Lb, and l3Lc are arranged in this order from the center toward the upper left with respect to the width direction of the vehicle. The illumination ranges of the sub headlight light sources l3La, l3Lb, and l3Lc overlapone another. The sub headlight unit I3R includes a plurality of sub headlight light sources l3Ra, !3Rb, and l3Rc. The sub headlight light sources !3Ra, l3Rb, and l3Rc are arranged in this order from the center toward the upper right with respect to the width direction of the vehicle. The sub headlight light sources l3Ra, l3Rb, and l3Rc illuminate an area ahead and right-lateral with respect to the width direction of the vehicle. Illumination ranges of the sub headlight light sources l3Ra, l3Rb, and !3Rc are arranged in this order from the center toward the upper right with respect to the width direction of the vehicle. The illumination ranges of the sub headlight light sources l3Ra, l3Rb, and l3Rc overlap one another. Optical axes of the sub headlight light sources !3La to l3Lc, l3Ra to !3Rc are fixed, and not moved in accordance with a lean angle. A reflector (not shown) of the sub headlight light source is also fixed, and not moved in accordance with the lean angle. In this embodiment, no particular limitation is put on the sub headlight light source. For example, an LED is adoptable. A mono-focus type light source îs also adoptable as the sub headlight light source. As for how the sub headlight light sources !3La to l3Lc, l3Ra to l3Rc are arranged in the motorcycle 10, the above-described arrangement manner is merely an illustrative example of the présent invention. The présent invention is not limited to this example.

[0057]

Flashers 14L and I4R, serving as direction indicators, are provided at both sides of the motorcycle I0 with respect to the width direction of the vehicle. The flashers 14L and 14R are configured such that only one of thcm is turned on in accordance with an operation performed on the flasher switch 15F (see FIG. 2) by the rider.

[0058]

The plurality of sub headlight light sources l3La, !3Lb, and l3Lc, which are positioned at the left side in the motorcycle 10 with respect to the width direction of the vehicle, are arranged between the main headlight 11 and the flasher 14L. The plurality of sub headlight light sources !3Ra, l3Rb, and l3Rc, which are positioned at the right side in the motorcycle 10, are arranged between the main headlight 11 and the flasher 14R. In the présent invention, no <

l i6 particular limitation is put on the positional relationship between the sub headlight light source and the flasher with respect to the width direction of the vehicle. For example, it may be acceptable that the sub headlight light source is provided outside the flasher with respect to the width direction ofthe vehicle.

[0059]

The plurality of sub headlight light sources l3La, !3Lb, and i3Lc are provided above the main headlight 11 and the flasher 14L. The plurality of sub headlight light sources l3Ra, l3Rb, and l3Rc are provided above the main headlight 11 and the flasher I4R.

[0060]

The plurality of sub headlight light sources l3La to !3Lc, which are provided to the left with respect to the width direction of the vehicle, illuminate an area ahead of and lefi-lateral to the motorcycle 10. The plurality of sub headlight light sources !3Ra to 13Rc, which are provided to the right with respect to the width direction of the vehicle, illuminate an area ahead of and right-lateral tothe motorcycle 10.

[0061]

FIG. 2 is a block diagram showing a basic configuration concerning the sub headlight lightsources 13Lato 13Lc, l3Rato 13Rcofthemotorcycle lOshown in FIG. I.

[0062]

The operation switch 15 includes the beam switch 1513 and the flasher switch 15F. The beam switch 15B is connected to the high beam light source I IH and the low beam light source 11L included in the main headlight 11. When the rider opérâtes the beam switch 15B, tum-on/turn-ofT of the high beam light source IIH and the low beam light source ] IL is switched in accordance with the operation performed on the beam switch 15B.

[0063]

The flasher switch 15F is connected to the fiashers 14L and 14R. When the rider opérâtes the flasher switch 15F, one of the fiashers I4L and 14R is caused to flash in accordance with the operation performed on the flasher switch 15 F.

[0064]

In the motorcycle 10, a Jean angle sensor 22 and a vehicle speed sensor 23 are provided. In this embodiment, the lean angle sensor 22 is a gyro sensor that detects the angular velocity about an axis in the front-back direction of the motorcycle 10. The lean angle sensor 22 supplies, to a controller 20, a signal indicating the detected angular velocity (roll rate) about the axis in the front-back direction. The vehicle speed sensor 23 detects the vehicle speed, and supplies, to the controller 20, a signal indicating the detected vehicle speed. Each tinie a predetermined titning cornes during running, the controller 20 calculâtes the lean angle of the motorcycle 10 based on the angular velocity about the axis in the front-back direction and the vehicle speed.

I7 [0065]

In tliis embodiment, the roll rate is integrated over time, and the vehicle spced is used as correction information, thereby calculatîng the lean angle. However, in the présent invention, a method for calculatîng the lean angle is not limited to tliis example. In the calculation of the lean angle, the vehicle speed is not an essential variable. For calculatîng the lean angle, a conventionally known method is adoptable. For example, the calculation ntay be performed based on a static equilibrium équation by using the yaw rate (angular velocïly about an axis in the vertical direction) and the vehicle speed. The correction information is not limited to the vehicle speed. For example, it may be acceptable to provide a plurality of gyro sensors and G sensors and use values obtained from these sensors and the vehicle speed as the correction information. Instead of the vehicle speed, GPS position information and/or geomagnetic information may be used as the correction information. No particular limitation is put on sensors (détection part) for detecting variables that are available for obtaining the lean angle. An appropriate sensor may be provided in accordance with variables available for the calculation.

[0066]

The controller 20 includes a memory (not shown).

The memory stores, in the form of data, a plurality of reference values K(°) to be compared with the lean angle. In tliis embodiment, the memory stores three reference values (a first reference value Ki, a second reference value K.2, and a third reference value Kj). The first reference value K|, the second reference value K2, and the third reference value Kj satisfy the relationship of “first reference value K| < second reference value K2 < third reference value K3.

[0067]

The memory stores, in the form of data, lower values T(°) to be compared with the lean angle. The lower value corresponds to the lean angle obtained when a light source that has been turned off is starting to light up in the course of an increase in the lean angle.

In this embodiment, the memory stores three lower values (a first lower value T|, a second lower value T2, and a third lower value T₃). The first lower value T|, the second lower value T2, and the third lower value Tj satisfy the relationship of “first lower value T; < second lower value T2 < third lower value Tj. Each of the lower values T is smaller than each corresponding reference value K. To be spécifie, the relationship of “first lower value T1 < first reference value Ki” is satisfied.

[0068]

The memory stores, in the form of data, upper values U(°) to be compared with the lean angle. The upper value corresponds to the lean angle obtained when a light source is starting to light up with the highest brightness in the course of an increase in the lean angle.

In this embodiment, the memory stores three upper values (a first upper value Ui, a second upper value U2, and a third upper value Uj). The first upper value Ui, the second upper value U2, and the third upper value Uj satisfy the relationship of first upper value Ui < second upper value U2 < third upper value U3”. Each of the upper values U is greater than each corresponding reference value K. To be spécifie, the relationship of “first reference value Ki <

first upper value Uf’ is satisfied.

[0069]

The memory stores, in the form of data, spécifie values l(°) to be compared with the lean angle. The spécifie value corresponds to the lean angle obtained when a light source that has lighted up with the highest brightness is starting to dim in the course of an increase in the lean angle.

In this embodiment, the memory stores two spécifie values (a first spécifie value l| and a second spécifie value I2). The first spécifie value h and the second spécifie value h satisfy lhe relationship of first spécifie value I_t < second spécifie value h. Each of the spécifie values l Îs greater than each corresponding upper value U. To be spécifie, the relationship of first upper value U| < first spécifie value h” is satisfied.

[0070]

The memory stores, in the form of data, defined values J(°) to be compared with the lean angle. The defined value corresponds to the lean angle obtained when the lowest brightness is achieved in the course of an increase in the lean angle beyond the spécifie value. While the lean angle is equal to or greater than the defined value, the state (brightness) obtained when the lean angle takes the defined value is maintained.

In this embodiment, the memory stores two defined values (a first defined value J| and a second defined value J₂). The first defined value J i and the second defined value J₂ satisfy the relationship of “first defined value Ji < second defined value J₃’’. Each of the defined values J is greater than each corresponding spécifie value I. To be spécifie, the relationship of first spécifie value li < first defined value J|” is satisfied.

[0071]

The first reference value K|, the first lower value T_t, the first upper value U|, the first spécifie value I|, and the first defined value Jj are associated with the sub headlight light sources 13La and 13Ra.

The second reference value K2, the second lower value T2, the second upper value U₂, the second spécifie value 1₂, and the second defined value J₂ are associated with the sub headlight light sources 13Lband 13Rb.

The third reference value K₃, the third lower value T3, and the third upper value Uj are associated with the sub headlight light sources !3Lc and 13Rc. The sub headlight light sources 13Lc and 13Rc, with which the greatest reference value is associated, bave no spécifie value and no defined value associated therewith.

The relationship between each variable and the brightness of the sub headlight light t

I source will be detailed later with reference to FIG. 4.

[0072]

An answerback main unit 21 is connected to the controller 20. The answerback main unit 21 receives a signal radio wave from a remote control key 25.

[0073]

The sub headlight light sources l3La to l3Lc, l3Ra to )3Rc are connected to the controller 20. A power source 26 (battery) is connected to the high beam light source I IH and the low beam light source l IL via the beam switch 15B. The power source 26 is connected to the flashers î4L and 14R via the flasher switch 15F. The power source 26 is connected to the controller 20.

[0074]

The controller 20 controls the brightnesses of the sub headlight light sources l3La to l3Lc, l3Ra to l3Rc. in this embodiment, the sub headlight light sources !3La to l3Lc, l3Ra to !3Rc are configured of LEDs. The controller 20 performs a puise width modulation control (PWM control) to adjust the duty cycle, and thereby the brightnesses are controlled (dimming control),

A method for performing the dimming control on the sub headlight light source is not particularly limited. For example, it may be conceivable to control a current to be supplied to the sub headlight light source, or to control a voltage to be supplied to the sub headlight light source.

[0075]

Alternatîvely, a single sub headlight light source may include a plurality of light sources having different brightnesses. In this case, the dimming control on the sub headlight light source can be implemented by switching which of the light sources is turned on, For example, in a case where a single sub headlight light source includes two light sources having different brightnesses, the brightness of the light source can be controlled by switching the turned-on light source from the light source configured to light up with a first brightness to the light source configured to light up with a second brightness.

[0076]

Furthermore, a single sub headlight light source may include a plurality of light sources. In this case, the dimming control on the sub headlight light source can be implemented by changing the number or combination of light sources that are turned on. The brightnesses of the plurality of light sources may be either different or the same. For example, in a case where a single sub headlight light source includes a plurality of light sources (for example, four light sources) having the same brightness, turning on part of the plurality of light sources enabies the sub headlight light source to light up with the first brightness, while turning on ail the plurality of light sources enabies the sub headlight light source to light up with the

second brightness.

[0077] ln the motorcycle I0, though not shown in FIG. 2, a voltage detector (not shown) for detecting a supply voltage that is supplted from the power source 26 to each of the sub headlight 5 light sources !3La to l3Lc, l3Ra to !3Rc may be provided in a cable that connecte the controller 20 to each of the sub headlight light sources l3La to !3Lc, !3Ra to l3Rc. A supply voltage value detected by the voltage detector is, in the form of data, supplied to the controller 20 at a predetermined timing, for example.

In this case, data indicating a reference voltage value of the power source 26 is stored I0 in the memory of the controller 20. The controller 20 performs an information acquisition process for acquiring data indicating the supply voltage value from the voltage detector, and compares the supply voltage value against the reference voltage value, to calculate a différence between the supply voltage value and the reference voltage value.

The memory of the controller 20 stores a data table indicating a correspondence 15 relationship of the rate of correction of the brightness of the sub headlight light source relative to the différence between the supply voltage value and the reference voltage value. In this data table, as the absolute value of the différence between the supply voltage value and the reference voltage value increases, the absolute value of the rate of correction of the brightness of the sub headlight light source increases. When a différence of the supply voltage value from the 20 reference voltage value is a positive value, the rate of correction is set to be a négative value. Accordingly, after correction, the brightness of the sub headlight light source is reduced as compared with that before the correction. On the other hand, when a différence of the supply voltage value from the reference voltage value is a négative value, the rate of correction is set to be a positive value. Accordingly, after correction, the brightness of the sub headlight light 25 source is increased as compared with that before the correction. A correction object to be corrected is not particularly limited. At least one of a voltage value, a current value, and a duty cycle value may be adopted as the correction object.

It may be also acceptable that the memory stores a table associating the supply voltage value with the rate of correction of the brightness of the sub headlight light source. In this table 30 data, the rate of correction is set based on the reference voltage value. In a case of using such a table data, it is not always necessary that the reference voltage value is stored in the memory, and the controller 20 does not bave to calculate the différence of the supply voltage value from the reference voltage value. In this case, an indirect comparison between the supply voltage value and the reference voltage value is performed. Furthermore, although the abovc-describcd 35 example describes a case where the memory includes the data table, the rate of correction may be calculated through computing with use of the supply voltage value or with use of the différence of the supply voltage value from the reference voltage value. Then, based on the rate of

2l correction thus obtained, the value of the correction object (such as the voltage, the current, the duty cycle) is corrected. Thereby, a change in the brightness of each of the sub headlight light sources l3La to l3Lc, 13Ra to l3Rc, which is caused by a variation in the supply voltage of the power source 26, can be suppressed. Here, it may be also possible that the controller 20 controls the supply voltage supplied to each of the sub headlight light sources l3La to !3Lc, so that the supply voltage supplied from the controller 20 to each of the sub headlight light sources !3La to l3Lc, 13Ra to l3Rc is made constant. In this case, the brightness of each of the sub headlight light sources l3La to l3Lc, !3Ra to !3Rc can be controlled by adjusting the current value or the duty cycle.

In this embodiment, when the lean angle of the motorcycle I0 is in a range of at least a lower limit value and less than the reference value, the above-described brightness control (adjustment process) is performed on the sub headlight light sources l3La to !3Lc, !3Ra to !3Rc, while when the lean angle is out of this range, the brightness control is not performed. Accordingly, at a time of causing the sub headlight light source to light up with a high brightness, an output of the sub headlight light source can be made without limitation, to make it possible to ensure a wide illumination range. However, the présent invention is not limited to this example. The above-described brightness control may be performed irrespective of the lean angle of the motorcycle 10.

[0078]

FIG. 3 is a front elevational view schematically showing optical axes and cut-off lines of the sub headlight light sources l3La to l3Lc, l3Ra to l3Rc of the motorcycle 10 in an upright state.

[0079]

The motorcycle 10 stands upright on a fiat ground G. An optical axis Ao of the low beam light source l IL is located below a horizon H of the low beam light source 11 L. A cutoff line Lo of the low beam light source l IL is located above the optical axis A_o, and located below the horizon H of the low beam light source l IL. The cut-off line L_n extends right and left along the width direction of the vehicle. An illumination range of the low beam light source l IL covers both of the right and left sides with respect to the width direction of the 30 vehicle.

[0080]

The optical axes ALi to AL₃ of the sub headlight light sources l3La to !3Lc are located outward in the order of the optical axes ALi to AL₃ with respect to the width direction of the vehicle. The optical axes AL; to AL₃ of the sub headlight light sources !3La to !3Lc are 35 located above the optical axis Ao of the low beam light source 11 L.

[0081]

Inclination angles 0) to 0₃ of cut-off lines LLi to LLj ofthe sub headlight light sources

l3La to l3Lc increase in the order of the inclination angles 0, to 0j.

The inclination angles 0; to Θ3 of the cut-off lines LL| to LL3 of the sub headlight light sources 13La to 13Lc are set to be values increasing at intervals from 0° to θι, 0₂, and 03 in this order. The interval between 0° and θι is 0|. When the interval between 0₂ and 0| is defined as 0₂’ and the intervai between θ3 and θ2 is defined as 03’, the intervals θι, 02’, and 63’ satisfy 0i>0₂’>03’. In other words, a larger inclination angle (0| to ©3) has a smaller interval (0|, 0₂’, θ3’). I lere, in the présent invention, the relationship among the inclination angles (0| to O3) ts not limited to this example. The intervals (0_t, 0₂’, 03*) may be regular intervals, that is, the relationship of 0|=02’=03’ may be established.

[0082]

No particular limitation is put on the relationship between the inclination angle (θι to O3) of the cut-off line (LL| to LL3) of each sub headlight light source (l3La to 13Lc) and the reference value (K| to K.3) set for the sub headlight light source ( 13La to 13Lc). These values (angles) may be either different or the same. A state where these values are the same includes a state where these values are substantially the same.

[0083]

The cut-off lines LL! to LL3 of the sub headlight light sources 13La to 13Lc define the upper end edges of the illumination ranges of the sub headlight light sources 13La to 13Lc, respectively, though not shown in FIG. 3. Therefore, the illumination ranges of the sub headlight light sources 13La to 13Lc are located below the cut-off lines LLt to LL3 of the sub headlight light sources !3La to 13Lc. Accordingly, each of the illumination ranges of the sub headlight light sources 13La to 13Lc includes a space above the horizon H, and their locations are higher in ascending order of the illumination range of the sub headlight light source 13La, the illumination range of the sub headlight light source i3Lb, and the illumination range of the sub headlight light source l3Lc. The illumination ranges of the sub headlight l3La to 13Lc are located at the left side with respect to the width direction of the vehicle.

Except for whether the sub headlight light sources are provided at the right side or the left side of the symmetry, the sub headlight light sources 13Ra to 13Rc are identical to the sub headlight light sources 13La to l3Lc described above. Therefore, a description thereof will be omîlted.

[0084]

Next, a change in the brightness of the sub headlight 13 in accordance with an increase in the lean angle will be described with reference to FIG. 4.

FIG. 4 is a cliart showing the relationship between the lean angle of the motorcycle 10 and the brightnesses of the sub headlight light sources l3La to l3Lc according to the first embodiment of the présent invention. Among brightnesses Qi to Q3 of the sub headlight light sources !3La to 13Lc, Qi represents a first brightness, Q₂ represents a second brightness, and Q3 represents a third brightness. The brightnesses Qi to Qj of the sub headlight light sources l3La to l3Lc satisfy the relatîonship of Qj<Qi<Q2.

[0085] [Lean Angle = 0°]

When the lean angle is 0°, each of the light sources of the sub headlight 13 is in the following state.

The sub headlight light source !3La is not turned on.

The sub headlight light source 13Lb is not turned on.

The sub headlight light source !3Lc is not turned on.

[0086] [0° < Lean Angle(°) < First Reference Value K|]

In the course of an increase in the lean angle from 0°, each of the light sources of the sub headlight 13 is as follows.

The sub headlight light source l3La starts to light up when the lean angle reaches the first lower value T| that is set for the sub headlight light source l3La. When the lean angle is in the range from the first lower value Tj to the first reference value K|, the brightness of the sub headlight light source !3La continuously increases along with the increase in the lean angle. That is, when the lean angle is in the range from the first lower value T| to the first reference value Ki, the sub headlight light source l3La lights up with a brightness lower than the first brightness Q|.

The sub headlight light source 13Lb is not turned on.

The sub headlight light source !3Lc is not turned on.

[0087] [Lean Angle{°) = First Reference Value K|]

When the lean angle reaches the reference value Ki that is set for the sub headlight light source !3La, each of the light sources of the sub headlight 13 is in the following state.

The sub headlight light source l3La lights up with the first brightness Qj.

The sub headlight light source 13Lb ïs not turned on.

The sub headlight light source 13Lc is not turned on.

[0088] [First Reference Value Ki < Lean Angle(°) < Second Reference Value K₂]

In the course of an increase in the lean angle from the first reference value Kj, each of the light sources of the sub headlight 13 is as follows.

The brightness of the sub headlight light source l3La continuously increases along with the increase in the lean angle until the lean angle reaches the first upper value Ui. When the lean angle reaches the first upper value Ui, the sub headlight light source l3La lights up with the second brightness Q;. When the lean angle is in the range from the first upper value Ui to >

the first spécifie value fi, the sub headlight light source !3La lights up with the second brighlness

Q;.

The sub headlight light source l3Lb slarts to light up when the lean angle reaches the second lower value T₂ that is set for the sub headlight light source l3Lb. When the lean angle is in the range from the second lower value T₂ to the second reference value K₂, the briglitness of lhe sub headlight light source 13Lb continuously increases along with the increase in the lean angle.

The sub headlight light source 13Lc is not turned on.

[0089] [Lean Angle(°) = Second Reference Value KJ

When the lean angle reaches the reference value K₂ that is set for the sub headlight light source !3Lb, each of the light sources of the sub headlight 13 is in the following state.

The sub headlight light source 13La lights up with the briglitness Q₂.

The sub headlight light source 13Lb lights up with the briglitness Q_h

The sub headlight light source 13Lc is not turned on.

[0090] [Second Reference Value K₂ < Lean Angle(°) < Third Reference Value KJ

In the course of an increase in the lean angle from the second reference value K₂, each of the light sources of the sub headlight 13 ts as follows.

The sub headlight light source 13La lights up with the second briglitness Q₂ unlil the lean angle reaches the first spécifie value I|. After the lean angle reaches the first spécifie value II, the brighlness of the sub headlight light source l3La continuously decreases along with the increase in the lean angle.

The brightness of the sub headlight light source l3Lb continuously increases along with the increase in the lean angle when the lean angle is in the range from the second reference value K₂ to the second upper value U₂. When the lean angle reaches the second upper value U₂, the sub headlight light source 13Lb lights up with the second brightness Q₂.

The sub headlight light source 13Lc starts to light up when the lean angle reaches the third lower value T₃ that is set for the sub headlight light source 13Lc. When the lean angle is in the range from the third lower value T₃ to the third reference value K₃, the brighlness of the sub headlight light source 13Lc continuously increases along with the increase in the lean angle.

[0091] [Lean Angle(°) = Third Reference Value KJ

When the lean angle reaches the reference value K₃ that is set for the sub headlight light source 13Lc, each ofthe light sources ofthe sub headlight 13 is in the following state.

The sub headlight light source l3La lights up with a brightness lower than the second brightness Q₂ and higher than the third brightness Q₃.

J

The sub headlight light source l3Lb lights up with the second brightness Q₂.

The sub headlight light source l3Lc lights up with the first brightness Qi.

[0092] [Third Reference Value K₃ < Lean Angle(°)]

In the course of an increase in the lean angle from the reference value K₃, each of the light sources ofthe sub headlight 13 is as follows.

The brightness of the sub headlight light source 13La continuously decreases along with the increase in the lean angle until the lean angle reaches the first defined value J|. When the lean angle is equal to or greater than the first defined value J|, the sub headlight light source 10 13La lights up with the brightness Q₃.

The sub headlight light source 13Lb lights up with the second brightness Q₂ until the Jean angle reaches the second spécifie value L. After the lean angle reaches the second spécifie value h, the brightness of the sub headlight light source 13Lb continuously decreases along with the increase in the lean angle. When the lean angle is equal to or greater than the second 15 defined value J2, the sub headlight light source 13Lb lights up with the brightness Q₃.

The sub headlight light source l3Lc lights up with the brightness Q₂ when the lean angle is equal to or greater than the upper value U₃.

[0093]

The brightnesses of the sub headlight light sources 13La to 13Lc are changed in accordance with the lean angle, as follows.

When the lean angle is equal to or greater than 0° and less than the lower value T] to T₃ that is set for the sub headlight light source l3La to l3Lc, the corresponding sub headlight light source 13La to 13Lc is turned off.

When the lean angle is equal to or greater than the lower value Ti to T₃ that is set for the sub headlight light source 13La to 13Lc and less than the reference value to K₃ that is set for the sub headlight light source 13La to 13Lc, the corresponding sub headlight light source 13La to 13Lc lights up with a brightness lower than the first brightness Q|. When the lean angle is equal to or greater than the lower value Ti to T₃ and less than the reference value K| to K₃, the brightness of the corresponding sub headlight light source 13La to 13Lc continuously increases along with an increase in the lean angle, and the brightness of the corresponding sub headlight light source 13La to 13Lc continuously decreases along with a decrease in the lean angle.

When the lean angle takes the reference value K| to K₃, the corresponding sub headlight light source 13La to 13Lc lights up with the first brightness Qp

When the lean angle is greater than the reference value K_E to K₃ and less than the upper value U| to U₃, the corresponding sub headlight light source 13La to 13Lc lights up with a brightness higher than the first brightness Qi and lower than the second brightness Q?. When

I the lean angle is greater than the reference value K.j to Kj and less than the upper value Ui to Uj, the brightness of the corresponding sub headlight light source !3La to l3Lc continuously increases along with an increase in the lean angle, and the brightness of the corresponding sub headlight light source l3La to !3Lc continuously decreases along with a decrease in the lean 5 angle.

When the lean angle takes the upper value U_f to U3, the corresponding sub headlight light source l3La to l3Lc lights up with the second brightness Q2.

In this embodiment, when the lean angle is equal to or greater than the lower value I’i to T3 that is set for the sub headlight light source 13La to 13Le and less than the reference value 10 K| to that is set for the sub headlight light source 13La to 13Lc, the brightness of the corresponding sub headlight light sources 13La to l3Lc continuously increases along with an increase in the lean angle. However, the présent invention is not limited to this example. In the présent invention, it suffices that, when the lean angle takes the lower value T| to T3, the corresponding sub headlight light source 13La to l3Lc lights up with a brightness lower than the 15 first brightness Q|. Therefore, the corresponding sub headlight light source 13La to 13Lc may light up with a predetermined brightness lower than the first brightness Q|. However, when the lean angle is equal to or greater than the lower value Tl to T3 that is set for the sub headlight light source l3La to i3Lc and less than the reference value Kl to K3 that is set for the sub headlight light source 13La to 13Lc, continuously increasing the brightness of the sub headlight 20 light source 13La to 13Lc in accordance with an increase in the lean angle causes the brightness of the sub headlight light source l3La to 13Lc to gradually increase. This can suppress occurrence of a situation where the corresponding headlight light source 13La to l3Lc suddenly lights up with a high brightness to make the rider feel uncomfortable.

[0094] ln this embodiment, the spécifie value and the defined value are not set for the sub headlight light source 13Lc having the greatest reference value set therefor among the plurality of sub headlight light sources 13La to l3Lc. Thus, even when the lean angle increases beyond the upper value U3, the sub headlight light source 13Lc having the greatest reference value set therefor keeps lighting up with the second brightness Q?.

On the other hand, for the sub headlight light sources 13La and 13Lb having the reference values smaller than the greatest reference value set therefor, the spécifie values E) and h and the defined values Ji and J2 are set, respectively.

When the Jean angle is greater than the upper value Ui, U2 and equal to or less than the spécifie value I|, h, the corresponding sub headlight light source 13La, 13Lb having the reference value smaller than the greatest reference value set therefor lights up with the second brightness Q2. When the lean angle is greater than the spécifie value l_t, I₂ and less than the defined value Ji, J2, the corresponding sub headlight light source 13La, l3Lb having the reference value smaller than the greatest reference value set therefor lights up with a brightness lower than the second brightness Q₂ and higher than the third brightness Qj. When the lean angle is greater than the spécifie value h, l₂ and less than the defined value J|, J₂, the brightness of the corresponding sub headlight light source !3La, !3Lb having the reference value smaller 5 than the greatest reference value set therefor continuously decreases along with an increase in the lean angle, and the brightness ofthe corresponding sub headlight light source !3La, l3Lb having the reference value smaller than the greatest reference value set therefor continuously increases along with a decrease in the lean angle. When the lean angle is equal to or greater than the defined value Ji, J₂, the corresponding sub headlight light source !3La, i3Lb lights up with the 10 third brightness Qj.

This embodiment describes a case where the spécifie value and the defined value are not set for one sub headlight light source l3Lc having the greatest reference value set therefor. However, the présent invention is not Iimited to this example. It may be acceptable that the spécifie values and the defined values are set for ail the sub headlight light sources l3La to !3Lc. I5 [0095]

In FIG. 4, the duty cycle of a voltage supplied to the sub headlight light source is adopted as an index of the brightness of the sub headlight light source. However, in the présent invention, the index of the brightness of the sub headlight light source is not Iimited to this example. Exaniples of the index include a supply voltage, a supplied current, an illuminance 20 obtained at a position at a predetermined distance from the light source, and a luminance of the light source. When any index is adopted, the above-described magnitude relationship (Qj<Qi<Q₂) among the brightnesses of the sub headlight light source is established. The brightnesses Qi, Q₂, and Q? are not particularly Iimited, and appropriately set as needed. In this embodiment, the sub headlight light sources !3La to l3Lc and the sub headlight light source 25 !3Ra to !3Rc adopl the same brightnesses Qi, Q₂, and Q₃. However, the présent invention is not Iimited to this example, and appropriate setting is made as needed.

[0096]

Next, a change in a screen light distribution of the headlight in accordance with the lean angle of the motorcycle 10 will be described with reference to FIGS. 5 to 7.

[0097]

FIG. 5(a) is a diagram schematically showing a screen light distribution obtained when the lean angle of the motorcycle I0 takes a value that is in the range from the lower value T] to the reference value Ki and is relatively close to the lower value Tp

An illumination range LB ofthe low beam light source l IL is located ahead in front of 35 the motorcycle 10. An illumination range SH| of the sub headlight light source l3La is located above a left portion of the illumination range LB. The cut-off line LL| of the sub headlight light source l3La is located above the horizon H. Here, the sub headlight light source !3La

lights up with a brightness lower than the brightness Qi (FIG. 4). [0098]

FIG. 5(b) is a diagram schematically showing a screen light distribution obtained when the lean angle of the motorcycle 10 takes a value that is in the range from the lower value T| to the reference value K| and is greater than the lean angle shown in FIG. 5(a).

ln FIG. 5(b), the illumination ranges LB and SHi tilt toward the lower left as compared with FIG. 5(a), The cut-off line LL| of the sub headlight light source 13La is adjacent to the horizon H at a location above the horizon H. Here, the sub headlight light source !3La lights up with a brightness lower than the brightness Qi and higher than the brightness in the state shown m FIG. 5(a) (FIG. 4).

[0099]

FIG. 5(c) is a diagram schematically showing a screen light distribution obtained when the lean angle of the motorcycle 10 takes the reference value K|.

ln FIG. 5(c), the illumination ranges LB and SHi tilt toward the lower left as compared with FIG. 5(b). The cut-off line LLi of the sub headlight light source 13La is located below the horizon H. The illumination range SH| of the sub headlight light source 13La is located in a space below the horizon H. Here, the sub headlight light source 13La lights up with the brightness Qi (FIG. 4).

[0100]

FIG. 6(a) is a diagram schematically showing a screen light distribution obtained when the lean angle of the motorcycle 10 takes the upper value Us.

ln FIG. 6(a), the illumination ranges LB and SHi tilt toward the lower left as compared with FIG. 5(c). The cut-off line LL| of the sub headlight light source 13La is located below the horizon H while tilting toward the lower left. Here, the sub headlight light source 13La lights up with the brightness Q2 (FIG. 4).

The cut-off line LL| obtained when the lean angle takes the reference value Ki (FIG. 5(c)) is closer to horizontal than the cut-off line LL| obtained when the lean angle takes the upper value Ui (FIG. 6(a)) and the cut-off line LLi obtained when the motorcycle 10 is in the upright state (FIG. 3). The sanie applies to the cut-off lines LL₂ and LLj, too, though not shown.

[0101]

FIG. 6(b) is a diagram schematically showing a screen light distribution obtained when the lean angle of the motorcycle 10 takes a value that is in the range from the lower value T2 to the reference value Kj.

ln FIG. 6(b), the illumination ranges LB and SH| tilt toward the lower left as compared with FIG. 6(a). An illumination range SH; of the sub headlight light source 13Lb is located above the illumination range SHi. The cut-off line LL; of the sub headlight light source 13Lb is adjacent to the horizon I J at a location above the horizon H. Here, the sub headlight light source 13Lb lights up with a brightness lower than the brightness Qi (FIG. 4).

[DI 02]

FIG. 6(c) is a diagram schematically showing a screen light distribution obtained when the lean angle of the motorcycle 10 takes the reference value K₂.

Jn FIG. 6(c), the illumination ranges LB, SHj, and SH₂ tilt toward the lower left as compared with FIG. 6(b). The cut-off line LL₂ of the sub headlight light source 13Lb is located below the horizon H. The illumination range SH₂ of the sub headlight light source l3Lb is located in a space below the horizon H. Here, the sub headlight light source l3Lb lights up with the brightness Qi (FIG. 4).

[0J03]

FIG. 7(a) is a diagram schematically showing a screen light distribution obtained when the lean angle of the motorcycle 10 takes a value that is in the range from the lower value T₃ to the reference value Kj.

In FIG. 7(a), the illumination ranges LB, SH|, and SH₂ tilt toward the lower left as compared with FIG. 6(c). An illumination range SHj of the sub headlight light source l3Lc is located above the illumination range SH₂. The cut-off line LLj of the sub headlight light source l3Lc is adjacent to the horizon H at a location above the horizon II. Here, the sub headlight light source 13Lc lights up with a brightness lower than the brightness Q> (FIG. 4).

[0104]

FIG. 7(b) is a diagram schematically showing a screen light distribution obtained when the lean angle ofthe motorcycle 10 takes the reference value Kj.

In FIG. 7(b), the illumination ranges LB, SH; to SHj tilt toward the lower left as compared with FIG. 7(a). The cut-off line LLj of the sub headlight light source !3Lc is located below the horizon H. The illumination range SII3 of the sub headlight ligln source !3Lc is located in a space below the horizon H. Here, the sub headlight light source l3Lc lights up with the brightness Q₂ (FIG. 4).

In the course ofan increase in the lean angle ofthe motorcycle IO (FIGS. 5(a) to 7(b)), it is préférable that the illumination range SH|, SH₂, or SHj of the sub headlight light source !3La, !3Lb, or l3Lc produced when the lean angle ofthe motorcycle IO reaches the lower value T, T₂, or Ta set for this sub headlight light source l3La, !3Lb, or l3Lc partially ovcrlaps the illumination range LB or the illumination range SH| or SH₂ of the low beam light source l IL or the sub headlight light source l3La or l3Lb, that has been turned on immediately before this sub headlight light source !3La, !3Lb, or I3Lc.

[0105]

Next, a change in an illumination range of the headlight in accordance with the lean angle ofthe motorcycle IO will be described with reference to FIGS. 8 to 17. In FIGS. 8 to 17,

X represents a straight ahead direction of the motorcycle 10 that leans into turns, and Y represents the left side with respect to the width direction of the motorcycle 10. The reference numéral 80 dénotés a path of the motorcycle I0. The path 80 curves to the left, with a predetermined radius.

[0I06]

FIG. 8 illustrâtes a light distribution, schematically showing an illumination range of the headlight produced on a road surface at a time when the lean angle of the motorcycle 10 takes a value that is in the range from the lower value T| to the reference value K! and is relatively close to the lower value T|.

[0107]

The illumination range LB of the low beam light source l IL having an illuminance L, spreads ahead of the motorcycle 10 along the advancing direction X. Since the motorcycle 10 is inclined to the left, the cut-off line Lo of the low beam light source l IL approaches to the motorcycle 10 from the left side of the motorcycle 10. Accordingiy, on the path 80, only a région relatively close to the motorcycle 10 is covered by the illumination range having the illuminance L|,

In running, the rider normally looks at a position on the path 80 ahead of the motorcycle I0. Therefore, the cut-off line L_o approaching to the motorcycle I0 enters the rider’s field of view.

[0)08]

On the other hand, the sub headlight light source !3La produces illumination along the optical axis AL;. Therefore, on the path 80, the illumination range SH| of the sub headlight light source !3La covers the cut-off line Lo of the low beam light source 11L. Accordingiy, the movement of the cut-off line Lo of the low beam light source 11L within the rider’s field of view is less likely to be conspicuous. Moreover, the cut-off line LL| of the sub headlight light source l3La is located at a relatively farther position ahead of the motorcycle I0. In a state shown in FIG. 8, the cut-off line LLi is less clear than the cut-off line Lo.

Moreover, a région on the path 80 covered by the illumination range having the illuminance Li is elongated. The illumination range SHi of the sub headlight light source l3La spreads over a position the rider desires to see.

[0)09]

FIG. 9 illustrâtes a light distribution, schematically showing an illumination range of the headlight produced on a road surface at a time when the lean angle of the motorcycle I0 takes a value that is in the range from the lower value Ti to the reference value K) and is greater than the lean angle shown in FIG. 8.

[0H0]

In a state shown in FIG. 9, the lean angle of the motorcycle 10 increases as compared with the state shown in FIG. 8. Therefore, the cut-off line L_o of the low beam light source 1 IL further approaches to the motorcycle 10 as compared with the state shown in FIG. 8. Accordingly, the région on the path 80 covered by the illumination range LB of the low beam light source I IL having the illuminance L, is shortened.

[OUI]

On the other hand, the briglitness of the sub headlight light source l3La increases in accordance with the increase in the Jean angle, and therefore the illumination range SH! is enlarged. As a resuit, the illumination range SH| of the sub headlight light source 13La still covers the cut-off line Lo of the low beam light source l IL on the path 80. Accordingly, the 10 movement ofthe cut-off line L_o ofthe low beam light source I IL within the rider’s field ofview is less likely to be conspicuous. Moreover, the cut-off line LL| of the sub headlight light source 13La is located at a relatively farther position ahead of the motorcycle 10. In the state shown in FIG. 9, the cut-off line LLj is less clear than the cut-off line L_o.

In the state shown in FIG. 9, the lean angle increases as compared with the state shown 15 in FIG. 8, but the brightness of the sub headlight light source 13La increases so that a région on the path 80 covered by the illumination range having the illuminance Li is ensured to the same extent as in the state shown in FIG. 8. As a result, (he illumination range SH| of the sub headlight light source l3La spreads over the position the rider desires to see (on the path 80).

[0112]

FIG, 10 illustrâtes a light distribution, schematically showing an illumination range of the headlight produced on a road surface at a tinte when the lean angle of the motorcycle 10 takes the reference value Ki.

[0113]

In a state shown in FIG. 10, the lean angle of the motorcycle 10 increases as compared 25 with the state shown in FIG. 9. Therefore, the cut-off line Lo of the low beam light source 1 IL further approaches to the motorcycle 10 as compared with the state shown in FIG. 9. Accordingly, the région on the path 80 covered by the illumination range LB of the low beam light source l IL having the illuminance Li is further shortened.

[0114]

On the other hand, the sub headlight light source 13La is lighting up with the first brightness Q<, and the brightness of the sub headlight light source 13La increases in accordance with the increase in the lean angle. Therefore, the illumination range SH| is enlarged. As a resuit, the illumination range SH| of the sub headlight light source )3La still covers the cut-off line Lo of the low beam light source 11L on the path 80. Accordingly, the movement of the cut35 off line Lo of the low beam light source I IL within the rider’s field of view is less ükely to be conspicuous.

In the state shown in FIG. 10, the lean angle increases as compared with the state

shown in FIG. 9, but the brightness of the sub headlight light source !3La increases so that a région on the path 80 covered by the illumination range having the iliumiiiance L| is ensured to the same estent as in the state shown in FIG. 9. As a resuit, the illumination range SHi of the sub headlight light source l3La spreads over the position the rider desires to see (on the path 80). The cut-off line LL| of the sub headlight light source 13La is located at the side (X side) of the illumination range SH, to which the motorcycle 10 is advancing. The cut-off line LL) extends right and left along the width direction of the vehicle (Y direction).

[0115]

FIG. 11 illustrâtes a light distribution, schematically showing an illumination range of the headlight produced on a road surface at a time when the lean angle of the motorcycle 10 takes the upper value U|. In this embodiment, the lower value T₂ is less than the upper value U). Therefore, when the lean angle of the motorcycle 10 takes the upper value U|, the sub headlight light source 13Lb has aiready started to light up. However, the illumination range SH₂ of the sub headlight light source 13Lb is not shown in FIG. 11, [0116]

In a state shown in FIG. 11, the lean angle of the motorcycle 10 increases as compared with the state shown in FIG. 10. Therefore, the cut-off line Lo ofthe low beam light source 1 IL further approaches to the motorcycle 10 as compared with the state shown in FIG. 10. In addition, the cut-off line LL) of the sub headlight light source 13La also approaches to the motorcycle 10 from the left side of the motorcycle 10.

[0117]

On the other hand, while the lean angle is increasing from the reference value K) to the upper value U|, the brightness of the sub headlight light source 13La is increasing from the first brightness Q_t to the second brightness Q₂. Therefore, the illumination range SH| of the sub headlight light source 13La is enlarged. In FIG. 11, a région SHf enclosed by the broken line indicates an illumination range of the sub headlight light source l3La obtained when the sub headlight light source 13La lights up with the first brightness Q). The illumination range SHi of the sub headlight light source l3La is larger than the région SUT enclosed by the broken line.

[0118]

Thus, in the motorcycle 10, when the lean angle increases from the reference value Ki to the upper value U), the cut-off line LL_t of the sub headlight light source 13La approaches to the motorcycle 10 along with the increase in the lean angle, but the illumination range SH) is enlarged in accordance with llie increase in the brightness of the sub headlight light source 13La from the first brightness Qi to the second brightness Q₂. Thereby, the speed of approach of the cut-off line LL| to the motorcycle 10 can be reduced.

[0119]

FIG. 12 illustrâtes a light distribution, schematically showing an illumination range of the headlight produced on a road surface at a time when the lean angle of the motorcycle 10 takes a value that is in the range from the lower value T₂ to the reference value K₂.

[0120]

In a state shown in FIG. 12, the lean angle ofthe motorcycle )0 increases as compared with the state shown in FIG. H. Therefore, the cut-off line LLj of the sub headlight light source l3La further approaches to the motorcycle I0 as compared with the state shown in FIG.

11. Accordingly, a région on the path 80 covered by the illumination ranges LB and SH| is shortened.

[0121]

On the other hand, the sub headlight light source !3Lb produces illumination along the optical axis AL₂. Therefore, on the path 80, the illumination range SH₂ of the sub headlight light source l3Lb covers the cut-off line LL| of the sub headlight light source !3La. Accordingly, the movement ofthe cut-off line LL| ofthe sub headlight light source l3La within the rider’s field of view is less likely to be conspicuous. Moreover, the cut-off line LL₂ of the sub headlight light source 13Lb is located at a relatively farther position ahead of the motorcycle

10. In the state shown in FIG. 12, the cut-off line LL₂ is less clear than the cut-off line LLi.

Moreover, a région on the path 80 covered by the illumination range having the illuminance L| is eiongated. The illumination range SH₂ of the sub headlight light source l3Lb spreads over the position the rider desires to see.

[0122]

FIG. 13 illustrâtes a light distribution, schematicaily showing an illumination range of the headlight produced on a road surface at a time when the lean angle of the motorcycle I0 takes the reference value K₂.

[0123] fil a state shown in FIG. 13, the lean angle of the motorcycle 10 increases as compared with the state shown in FIG. 12. Therefore, the cut-off line LL| of the sub headlight light source !3La further approaches to the motorcycle 10 as compared with the state shown in FIG.

12. Accordingly, the région covered by the illumination range SHj of the sub headlight light source 13La having the illuminance Li is further shortened.

[0124]

On the other hand, the sub headlight light source l3Lb is lighting up witli the first brightness Qi, and the brightness of the sub headlight light source 13Lb increases along with the increase in the lean angle. Therefore, the illumination range SH₂ is enlarged. As a resuit, the illumination range SH₂ of the sub headlight light source 13Lb still covers the cut-off line LLi of the sub headlight light source 13La on the path 80. Accordingly, lhe movement of the cut-off line LL| ofthe sub headlight light source 13La within the rider’s field of view is less likely to be conspicuous.

In the state shown in FIG. 13, the lean angle increases as compared with the state shown in FIG. 12, but the brightness of the sub headlight light source 13Lb increases so that a région on the path 80 covered by the illumination range having the illuminance Li is ensured to the same extent as in the state shown in FIG. 12. As a resuit, the illumination range SH2 of the sub headlight light source 13Lb spreads over the position (lie rider désires to see (011 the path 80). The cut-off line LL2 of the sub headlight light source 13Lb is located at the side (X side) of the illumination range SH2 to which the motorcycle 10 is advancing. The cut-off line LL2 extends right and left along the wîdth direction of the vehicle (Y direction).

[0125]

FIG. 14 illustrâtes a light distribution, schematïcally showing an illumination range of the headlight produced on a road surface at a time when the lean angle of the motorcycle 10 takes the upper value U2. In this embodiment, the lower value T3 is less than the upper value U2. Therefore, when the lean angle of the motorcycle 10 takes the upper value U2, the sub headlight light source 13Lc has already started to light up. However, the illumination range SH3 ofthe sub headlight lightsource 13Lc is not shown in FIG. 14.

[0126] in a state shown in FIG. 14, the lean angle of the motorcycle 10 increases as compared with the state shown in FIG. 13. Therefore, the cut-off line LL, of the sub headlight light source l3La further approaches to the motorcycle 10 as compared with the state shown in FIG.

13. The cut-off line LL₂ of the sub headlight light source 13Lb also approaches to the motorcycle 10 from the left side of the motorcycle 10.

[0127]

On the other hand, while the lean angle is increasing from the reference value K? to the upper value U2, the brightness of the sub headlight light source 13Lb is increasing from the first brightness Qi to lhe second brightness Q,. Therefore, the illumination range Sl h of the sub headlight light source 13Lb is enlarged. In FIG. 14, a région SH2’ enclosed by the broken line indicates an illumination range of the sub headlight light source 13Lb obtained when the sub headlight light source 13Lb iights up with the first brightness Qi. The illumination range Sfh of the sub headlight light source 13Lb is larger than the région SH2’ enclosed by the broken line.

[0128]

Thus, in the motorcycle 10, when the lean angle increases from the reference value K2 to the upper value U2, the cut-off line LL2 of the sub headlight light source 13Lb approaches to the motorcycle 10 along with the increase in the lean angle, but lhe illumination range SH₂ is enlarged along with the increase in the brightness of the sub headlight light source 13Lb front the first brightness Qi to the second brightness Q2. Thereby, the speed of approach of the cut-off line LL2 to the motorcycle 10 can be reduced.

[0129]

FIG. 15 illustrâtes a light distribution, schematically showing an illumination range of the headlight produced on a road surface at a time when the lean angle of the motorcycle 10 takes a value that is in the range from the lower value T₃ to the reference value K₃.

[0130]

In a state shown in FIG. 15, the lean angle of the motorcycle I0 increases as compared with the state shown in FIG. 14. Therefore, the cut-off line LL₂ of the sub headlight light source l3Lb further approaches to the motorcycle 10 as compared with the state shown in FIG.

14. Accordingly, a région on the path 80 covered by the illumination ranges LB, SH_h and SH₂ is shortened.

[0131]

On the other hand, the sub headlight light source l3Lc produces illumination along the optical axis ALj. Therefore, on the path 80, the illumination range SH₃ of the sub headlight light source l3Lc covers the cut-off line LL₂ of the sub headlight light source l3Lb. Accordingly, the movement of the cut-off line LL₂ of the sub headlight light source l3Lb within the rider's field of view is less likely to be conspicuous.

Moreover, a région on the path 80 covered by the illumination range having the illuininance L| is elongated. The illumination range SH₃ ofthe sub headlight light source 13Lc spreads over the position the rider desires to see.

[0132]

FIG. 16 illustrâtes a light distribution, schematically showing an illumination range of the headlight produced on a road surface at a time when the lean angle of the motorcycle I0 takes the reference value K₃.

[0133] ln a state shown in FIG. 16, the lean angle of the motorcycle I0 increases as compared with the state shown in FIG. 15. Therefore, the cut-off line LL₂ of the sub headlight light source l3Lb further approaches to the motorcycle 10 as compared with the state shown in FIG.

15. Accordingly, the région covered by the illumination range SH₂ of the sub headlight light source 13Lb having the illuminance L| is further shortened.

[0134]

On the other hand, the sub headlight light source l3Lc îs lighting up with the first brightness Qi, and the brightness of the sub headlight light source l3Lc increases along with the increase in the lean angle. Therefore, the illumination range SH₃ is enlarged. As a resuit, the illumination range SH₃ of the sub headlight light source l3Lc still covers the cut-off line LL₂ of the sub headlight light source !3Lb on the path 80. Accordingly, the movement of the cut-off Une LL₂ ofthe sub headlight light source î3Lb within the rider’s field ofview is less likely to be conspicuous.

In the state shown in FIG. 16, the lean angle increases as compared with the state shown in FIG. 15, but the brightness of the sub headlight light source l3Lc increases so that a région on the path 80 covered by the illumination range having the illuminance Li is ensured to the same extent as in the state shown in FIG. 15. As a resuit, the illumination range SHj of the sub headlight light source !3Lc spreads over the position the rider desires to see (on the path 80). The cut-off line LL3 of the sub headlight light source 13Lc is located at the side (X side) of the illumination range SH₃ to which the motorcycle 10 is advancing. The cut-off line LL₃ extends right and left along the width direction of the vehicle (Y direction).

[0135]

FIG. 17 illustrâtes a light distribution, scheinatically showing an illumination range of the headlight produced on a road surface at a time when the lean angle of the motorcycle I0 takes the upper value U₃.

[0136]

In a state shown in FIG. 17, the lean angle of the motorcycle 10 increases as compared with the state shown în FIG. 16. Therefore, the cut-off line LL2 of the sub headlight light source l3Lb further approaches to the motorcycle 10 as compared with the state shown in FIG.

I6. The cut-off line LL3 of the sub headlight light source l3Lc also approaches to the motorcycle I0 from the left side of the motorcycle 10.

[0I37]

On the other hand, while the lean angle is încreasing from the reference value K₃ to lhe upper value U₃, the brightness of the sub headlight light source l3Lc is încreasing from the first brightness Qi to the second brightness Qj. Therefore, the illumination range SH3 of the sub headlight light source l3Lc is enlarged. In FIG. 17, a région SH3’ enclosed by the broken line indicates an illumination range of the sub headlight light source l3Lc obtained when the sub headlight light source l3Lc (ights up with the first brightness Qi. The illumination range SH3 of the sub headlight light source l3Lc is largerthan the région SH3’ enclosed by the broken line.

[0138]

Thus, in the motorcycle 10, when lhe lean angle increases from the reference value K₃ to the upper value U₃, the cut-off line LL3 of the sub headlight light source l3Lc approaches to the motorcycle 10 along with the increase in the lean angle, but the illumination range SH3 is enlarged along with the increase in the brightness of the sub headlight light source l3Lc from the first brightness Qi to the second brightness Q₃. Thereby, the speed of approach of the cut-off line LL3 to the motorcycle I0 can be reduced.

[0I39]

FIG. 18 is a diagram showing the relatîonshîp between the lean angle of the motorcycle I0 and an illumination distance of the headlight illuminating the path of the motorcycle 10 according to the first embodiment of the présent invention. The points P8 to P17 correspond to situations shown in FIGS. 8 to 17, respectively.

[0140]

As the motorcycle 10 is inclined to the left so that the lean angle increases from 0°, the cut-off line Lo of the low beam light source l IL approaches to the motorcycle 10 from the left side of the motorcycle I0. Therefore, a path irradiation range (which means a distance on the path 80 from the motorcycle 10 lo the most distal end ofthe illumination range) becomes shorter along with the increase in the lean angle. Then, when the lean angle exceeds the lower value Tt, the sub headlight light source l3La is turned on so lhat the illumination range SH| of the sub headlight light source l3La is produced (PS). This extends the path irradiation range. Then, along with the increase in the lean angle, the brightness of the sub headlight light source !3La increases to enlarge the illumination range SH_h thus extending the path irradiation range (P9 to PIO).

[0141]

After the lean angle reaches the reference value K| (PIO), the cut-off line LL| of the sub headlight light source l3La approaches to the motorcycle I0 along with the increase in the lean angle. On the other hand, the brightness of the sub headlight light source !3La increases from the first brightness Qi to the second brightness Q₂, to enlarge the illumination range SH|. As a resuit, the speed of movement of the cut-off line LLi to the motorcycle 10 drops, which suppresses a réduction in the path irradiation range along with the increase in the lean angle (PU).

[0142]

When the lean angle further increases, the sub headlight light source 13Lb is turned on so that the illumination range Sl-h of the sub headlight light source l3Lb is produced. Then, along with the increase in the lean angle, the brightness of the sub headlight light source 13Lb increases to enlarge the illumination range SH2, thus extending the path irradiation range (P 12).

[0143]

After the lean angle reaches the reference value K2 (P 13), the cut-off line LL; of the sub headlight light source l3Lb approaches to the motorcycle 10 along with the increase in the lean angle. On the other hand, the brightness of the sub headlight light source 13Lb increases from the first brightness Qi to the second brightness Q₂, to enlarge the illumination range SH₂. As a resuit, the speed of movement of the cut-off line LL₂ to the motorcycle 10 drops, which suppresses a réduction in the path irradiation range along with the increase in the lean angle (P14).

[0144]

When the lean angle further increases, the sub headlight light source l3Lc is turned on so that the illumination range SH3 of the sub headlight light source 13Lc is produced. Then, along with the increase in the lean angle, the brightness of the sub headlight light source l3Lc increases to enlarge the illumination range SHj, thus extending the path irradiation range (P 15).

[ΟΙ 45]

After the lean angle reaches the reference value Kj (Pl6), the cut-off line LL₃ of the sub headlight light source !3Lc approaches to the motorcycle I0 along with the increase in the lean angle. On the other hand, the brightness of the sub headlight light source i3Lc increases from the first brightness Q( to the second brightness Q₂, to enlarge the illumination range SHj. As a resuit, the speed of movement of the cut-off line LL₃ to the motorcycle 10 drops, which suppresses a réduction in the path irradiation range along with the increase in the lean angle (P 17).

[0146] <Second Embodiment*

In the case illustrated in the above-described first embodiment, when the lean angle reaches the reference value K (K_t to K₃), the sub headlight light source lights up with the first brightness Qi, and when the lean angle is shilling from the reference value K. (K| to K₃) to the upper value U (Ui to U₃), the brightness of the sub headlight light source changes from the first brightness Qi to the second brightness Q₂. However, the présent invention is not limited to this example. For exampïe, a second embodiment is adoptable.

[0147]

FIG. 19 is a chart showing the relationship between the lean angle of the motorcycle 10 and the brightnesses of the sub headlight light sources l3La to 13Lc according to the second embodiment ofthe présent invention.

[0148]

In the motorcycle 10 according to the second embodiment of the présent invention, the upper value U (Ut to U₃) is not set. In the motorcycle 10 according to the second embodiment, as shown in FIG. 19, when the lean angle of the motorcycle 10 reaches the lower value T (T| to T₃), the sub headlight light source 13 ( 13La to l3Lc) starts to light up, and the brightness of the sub headlight light source 13 ( 13La to 13Lc) gradually increases in accordance with an increase in the lean angle. When the lean angle of the motorcycle 10 takes the reference value K (K_t to K₃), the sub headlight light source 13 (!3La to l3Lc) lights up with the second brightness Q₂.

When the lean angle is equal to or greater than the reference value K (K| to K₃), the sub headlight light source 13 (13La to l3Lc) lights up in the same manner as in the first embodiment (FIG. 4), except that, at a time point when the lean angle takes the reference value K, the sub headlight light source 13 ( 13La to 13Lc) lights up with the second brightness Q₂. Therefore, a description of the manner will be omitted.

[0)49]

FIG. 20 is a diagram showing the relationship between the lean angle of the motorcycle 10 and the illumination distance of the headlight illuminating the path of the motorcycle 10 according to the second embodiment of the présent invention. The points P8, P9,

PI0, P12, PI3, P15, and Pl6 correspond to situationsshown in FIGS. 8,9, 10, 12, 13, I5, and 16, respectively.

[0150]

As the motorcycle 10 is inclined to the loft so that the lean angle increases from 0°, the cut-off line Lo of the low beam light source l IL approaches to the motorcycle 10 from the ieft side of the motorcycle 10. Therefore, the path irradiation range becomes shorter along with the increase in the lean angle. Then, when the lean angle exceeds the lower value Ti, the sub headlight light source l3La is turned on so that the illumination range SH| of the sub headlight light source l3La is produced (P8). This extends the path irradiation range. Then, along with the increase in the lean angle, the brightness of the sub headlight light source l3La increases to enlarge the illumination range SHj, thus extending the path irradiation range (P9). When the lean angle reaches the reference value K|, the sub headlight light source l3La lights up with the second brightness Q₂ (PiO).

[0151]

After the lean angle reaches the reference value K_b the cut-off line LLj of the sub headlight light source l3La approaches to the motorcycle J0 along with the increase in the lean angle, On the other hand, when the lean angle reaches the lower value T_2l the sub headlight light source 13Lb is turned on so that the illumination range SH₂ of the sub headlight light source 13Lb is produced. Then, along with the increase in the lean angle, the brightness of the sub headlight light source 13Lb increases to enlarge the illumination range SHj, thus extending the path irradiation range (P 12). When the lean angle reaches the reference value K₂, the sub headlight light source 13Lb lights up with the second brightness Q₂ (PI 3).

[0152]

After the lean angle reaches the reference value K_2| the cut-off line LL₂ of the sub headlight light source 13Lb approaches to the motorcycle 10 along with the increase in the lean angle. On the other hand, when the lean angle reaches the lower value T3, the sub headlight light source 13Lc ïs turned on so that the illumination range SHj of the sub headlight light source l3Lc is produced. Then, along with the increase in the lean angle, the brightness of the sub headlight light source 13Lc increases to enlarge the illumination range SI-I,, thus extending the path irradiation range (P 15). When the lean angle reaches the reference value K₃, the sub headlight light source 13Lc lights up with the second brightness Q₂ (PI 6).

[0153]

As thus far described, in the motorcycle 10, al a time point when the lean angle reaches the lower value T, the sub headlight light source 13La to l3Lc lights up with a brightness lower than the first brightness Qi (the second brightness Q₂ in the second embodiment), and when the lean angle reaches the reference value K, the sub headlight light source l3La to 13Lc lights up with the first brightness Qi (the second brightness Q₂ in the second embodiment). Accordingly, when the illumination range of the low beam light source l IL or the sub headlight light source 13La or 13Lb that has been already turned on is moving away from the position the rider desires to see, the illumination range of the sub headlight light source 13La to l3Lc that is subsequently turned on can spread over the position the rider desires to see. As a resuit, the cut-off line LLi to LLj of the sub headlight light source 13La Ιο 13Lc that is subsequently turned on is likely to be conspicuous. The illumination range of the sub headlight light source 13La to I3Lc that is subsequently turned on is enlarged along with an increase in the brightness. Therefore, an effect of reducing the speed of approach of the cut-off line LL| to LL₃ to the motorcycie 10 is exerted. This enables suppression of an uncomfortable feeling, which may otherwîse be given to the rider.

Since a réduction in the illumination ranges of the sub headlight light sources l3La to 13Lc is suppressed, occurrence of a time period during which the position the rider desires to see is not sufflciently covered by the illumination ranges SHi to SH₃ of the headlight can be suppressed. This enables suppression of an uncomfortable feeling, which may otherwîse be given to the rider.

Moreover, when the lean angle is in the range between the lower value T (Ti to T₃) and the reference value K (K_t to K₃), the sub headlight light source 13La to 13Lc lights up with a brightness lower than the first brightness QJtlie second brightness Q₂ in the second embodiment), and when the lean angle subsequently reaches the reference value K (Ki to K₃), the sub headlight light source 13La to 13Lc lights up with the first brightness Qi (the second brightness Q₂ in the second embodiment). This enables suppression of occurrence of a situation where the sub headlight light sources l3La to l3Lc suddcnly lights up with a high brightness, which may make the rider feel uncomfortable.

[0153]

In the motorcycie 10 according to these embodiments, the sub headlight 13 is composed of the sub headlight units 13L and I3R, each of which is provided at each side with respect to the width direction of the vehicle. However, the présent invention is not limited to this example. For example, in a possible configuration, the sub headlight units J3L and 13R each provided at each side with respect to the width direction of the vehicle are formed intégral with each other, as a single sub headlight unit. In this case, the single sub headlight unit lias, at each side thereof with respect to the width direction of the vehicle, a plurality of headlight light sources that generate illumination ranges at onc side with respect to the width direction of the vehicle.

[0155]

These embodiments describe a case where each of the sub headlight units 13L and 13R is a physicaliy integrated unit. However, the présent invention is not limited to this example. It may be possible that the sub headlight unit I3L is physicaliy divided into the sub headlight

light sources 13La to l3Lc. In this case, it may bc possible that these sub headlight light sources 13La to 13Lc are assembled into a single sub headlight unit I3L which is then installed in the motorcycle 10 (vehicle). It inay be also possible that each of the sub headlight light sources 13La to 13Lc is individually installed in the motorcycle 10. In this case, the sub headlight light sources 13La to 13Lc, in astate of being installed in the motorcycle 10, constitute a single sub headlight unit 13L.

[0156]

In these embodiments, the sub headlight units 13L and 13R are members separate from the main headlight 11. However, the présent invention is not limited to this example. It may be acceptable that a sub headlight unit is integrated with a main headlight.

[0157]

The lean angle sensor 22 and the vehicle speed sensor 23 correspond to a détection part for detecting variables available for obtaining the lean angle of the motorcycle 10. Although the détection part includes the lean angle sensor 22 and the vehicle speed sensor 23 in these embodiments, the présent invention is not limited to this example. For example, the détection part may include the lean angle sensor 22 while not including the vehicle speed sensor 23. The controller 20 corresponds to a control part of the présent invention. However, a hardware configuration of the présent invention is not limited to this example. The control part détermines whether or not the lean angle of the motorcycle 10 has reached the reference value based on the variables detected by the détection part. At this time, it is not always necessary that the control part calculâtes the lean angle. No particular limitation is put on details of processing performed in the control part. For exampie, it may be possible that a memory provided in the controller 20 serving as the control part stores, in the form of data, a table in which the angular velocity (roll rate) and the vehicle speed are associated with a resuit of whether or not the lean angle has reached a first reference value. In this case, the control part refers to the table based on the angular velocity and the vehicle speed, and thereby can déterminé whether or not the lean angle has reached the first reference value without calculating the lean angle.

[0158]

In these embodiments, the lean angle is the angle of inclination ofthe vehicle body to the inner side of a curve relative to the upright state (vertical direction). However, the présent invention is not limited to this example. The lean angle may be the angle of inclination of the vehicle body to the inner side of a curve relative to a direction perpendicular to a road surface. As a method and a device for measuring the angle of inclination of the vehicle body to the inner side of a curve relative to the direction perpendicular to the road surface, conventionally known ones are adoptable.

[0159]

These embodiments describe a case where the sub headlight units I3L and 13R are members separate from the control part (controJler 20) and the détection part (the lean angle sensor 22 and the vehicle speed sensor 23). However, the présent invention is not limited to this example. The sub headlight unit may include at Ieast one of the control part, the 5 communication part, and the détection part.

[0160]

In these embodiments, three sub headlight light sources are provided at each side of the vehicle with respect to the width direction of the vehicle. in the présent invention, however, no particular limitation is put on the number of light sources. Il is préférable that the number of 10 sub headlight light sources that illuminate one side of the vehicle with respect to the width direction of the vehicle is at Ieast three.

[0161]

In these embodiments, each of the sub headlight light sources and the low beam light source is constituted of one light source, and one reference value is set for this one light source.

However, în the présent invention, the number of light sources that constitute one sub headlight light source or the low beam light source is not particularly limited. For example, it may be acceptable that one sub headlight light source or the low beam light source is constituted of a plurality of light sources and one reference value is set for the plurality of light sources.

[0162]

These embodiments describe a case where the reference value used when the lean angle increases so that the brightness of the sub headlight light source increases is the same as lhe reference value used when the lean angle decreases so thaï the brightness of the sub headlight light source decreases. Instead, these reference values may be different from each other.

[0163]

These embodiments describe a case where the sub headlight light source Îs turned on in accordance with the lean angle. However, the présent invention is not limited to this example. The sub headlight light source may bc configured such that a turn-on function in accordance with the lean angle is manually activatcd or deactivated. To be spécifie, it may be possible that the function is manually put into a standby state and, in the standby state, the sub 30 headlight light source is turned on in accordance with the lean angle. In this case as well, the sub headlight light source is turned on not manually but in accordance with the lean angle. In the flasher, on the other hand, flashing/tum-off is manually swîtclied. Also, in the main headlight, the îlluminating direction is manually switched. In this manner, the sub headlight light source is different from the flasher and the main headlight.

The sub headlight light source may be also configured such that an instruction for turnon or turn-off is manually inputted. In such a case, when the instruction is not inputted, the brightness of the sub headlight light source is changed in accordance with the lean angle, while when the instruction is inputted, turn-on or tum-off is performed in accordance with the instruction. For example, when the instruction for tum-on is inputted, the sub headlight light source is turned on irrespective of lhe lean angle. When the instruction for turn-off is inputted, the sub headlight light source is turned off irrespective of the lean angle, In such a case, the sub headlight system includes an input part (for example, a switch) to which the instruction for turning on or off the sub headlight light source is manually inputted. When the instruction is inputted, the control part turns on or off the sub headlight light source in accordance with lhe instruction. When the instruction is not inputted, the control part changes the brightness of the sub headlight light source in accordance with the lean angle. In this case as well, the sub headlight light source is different from the flasher and the main headlight, in that a function of turning on the sub headlight light source in accordance with the lean angle is provided.

The sub headlight light source may be configured such that, when the lean angle is equal to or larger than a minimum reference value, the brightness is changed in accordance with the lean angle, while when the lean angle is less than the minimum reference value (for example, al a time of running straight ahead), the brightness is manually changed. In this case as well, the sub headlight light source îs different from the flasher and the main headlight, in that a function of turning on the sub headlight light source in accordance with the lean angle is provided.

[0164]

In the description of this embodiment, the sub headlight light source is turned on in accordance with the lean angle. Here, lhe sub headlight light source is turned on in accordance with the lean angle because the sub headlight light source functions mainly as a light for ensuring the field of view of the rider of the vehicle. Therefore, in a well-lit situation, for example, in daytime, the sub headlight light source may not necessarily be turned on in accordance with the lean angle.

[0165]

The above embodiments describe a case where the voltage detector for detecting the supply voltage value of the voltage that is supplied to the sub headlight light source is provided. However, lhe présent invention is not limited to this example. For example, a température detector for detecting the température of the sub headlight light source or the vicinity thereof may be provided.

In this case, the control part (controller) perforais such a control that the brightness of the sub headlight light source increases as the température detected by the température detector is higher. Alternativeiy, the control part may perforai such a control that the brightness of the sub headlight light source increases in a case where the température detected by the température detector is equal to or higher than a predetermined température. Tins can correct a réduction in the brightness of the sub headlight light source caused by a température rise.

[0166]

In the présent invention, it may be possible that the control part perforais a distance Information acquisition process and an adjustment process. In the distance information acquisition process, distance information indicating a distance the vehicle has traveled is acquired from a tripmeter or the like. In the adjustment process, the brightness of the sub headlight light source, which changes in accordance with the lean angle of the vehicle, is adjusted based on the distance information. In this case, the control part (controller) performs such a control that the brightness of the sub headlight light source increases as the distance the vehicle has traveled is longer. This can correct a réduction În the brightness of the sub headlight light source caused by a long-term use.

[0167]

Furthermore, in the présent invention, it may be possible that the control part performs a time information acquisition process and an adjustment process. In the time information acquisition process, time information indicating a period of use of the vehicle or the sub headlight light source is acquired. In the adjustment process, the brightness of the sub headlight light source, which changes in accordance with the lean angle of the vehicle, is adjusted based on the time information acquired as a resuit of the lime information acquisition process. In this case, the control part can acquire the time information based on information of the current time, which is obtained by a clock or the like, and information indicating the time and date when the use of the vehicle or the sub headlight light source was started, which is stored in the memory. Il may be also possible that the vehicle is configured to acquire, through wireless communication, the time information indicating the period of use of the vehicle or the sub headlight light source from an external storage device (for example, a server) remote from the vehicle. In this case, the control part performs such a control that the brightness of the sub headlight light source increases as the period of use indicated by the time information is longer. This can correct a réduction in the brightness of the sub headlight light source caused by a long-term use.

[0168]

In the above-described example, the brightness ofthe sub headlight light source, which changes in accordance with the lean angle, is corrected based on the température, the travel distance, and the period of use. In the présent invention, when the lean angle of the vehicle is in a range of at least the lower limit value and less than the reference value, such a correction (adjustment process) is performed, while when the lean angle of the vehicle is out of this range, such a correction is not performed. Accordingly, at a time of causing the sub headlight light source to light up with a high brightness, an output of the sub headlight light source can be made without limitation, to make it possible to ensure a wide illumination range. However, the présent invention is not limited to this example. The above-described brightness control may be performed irrespective of the lean angle of the vehicle.

[0l 69]

ΙΟ motorcycle (vehicle that leans into turns) main headlight

I IH high beam light source

11L low beam light source handlebar sub headlight

I3L, 13R sub headlight unit !3La, l3Lb, l3Lc, !3Ra, 13Rb, !3Rc sub headlight light source I4L, I4R flasher operation switch front wheel frontfork front cover controller lean angle sensor vehicle speed sensor path

Claims (4)

1. CLAIMS [Claim I]

   A sub headlight unit for use in a vehicle thaï leans into turns, wherein the sub headlight unit includes a sub headlight light source that illuminâtes, al one side with respect to a width direction of the vehicle, an area ahead and outward of the vehicle with respect to the width direction of the vehicle, the brightness of the sub headlight light source changes in accordance with a lean angle of the vehicle, when the lean angle of the vehicle leaning to the one side with respect to the width direction of the vehicle reaches a reference value that is set for the sub headlight light source, the sub headlight light source lights up with a first brightness, and in a period from when the lean angle of the vehicle reaches a lower value that is less than the reference value to when the lean angle of the vehicle reaches the reference value, the sub headlight light source lights up with a brightness lower than the first brightness.
2. [Claim 2]

   The sub headlight unit according to claim I, wherein when the lean angle of the vehicle reaches the lower value that is set for the sub headlight light source, an illumination range of the sub headlight light source contains a space above a horizontal line, when the lean angle of the vehicle reaches the reference value that is set for the sub headlight light source, the illumination range of the sub headlight light source is located in a space below the horizontal line.
3. [Claim 3]

   The sub headlight unit according to claim 1 or 2, wherein a cut-off line of the sub headlight light source obtained when the lean angle of the vehicle reaches the reference value that is set for the sub headlight light source is doser to horizontal than the cut-off line of the sub headlight light source obtained when the lean angle of the vehicle reaches the lower value that is set for the sub headlight light source.
4. [Claim 4]

   The sub headlight unit according to any one of claims 1 to 3, wherein the sub headlight light source comprises a plurality of the sub headlight light sources, the reference value and the lower value arc individually set for each of the sub headlight light sources.

   (Claim 5]

   The sub headlight unit according to claim 4, wherein the reference value of one sub headlight light source is equal to or smaller than the lower value of another sub headlight light source for which the ncxt greatest reference value after that of the one sub headlight light source is set.

   [Claim 6]

   The sub headlight unit according to any one of ciaims l to 5, wherein an optical axis of the sub headlight light source is fixed, the sub headlight light source whose optical axis is fixed lights up with the first brightness when the lean angle of the vehicle reaches the reference value that is set for the sub headlight light source, and lights up with a brightness lower than the first brightness in the period from when the lean angle of the vehicle reaches the lower value that is less than the reference value to when the lean angle of the vehicle reaches the reference value.

   [Claim 7]

   A sub headlight system for use in a vehicle that leans into turns, the sub headlight system comprising:

   the sub headlight unit according to any one of ciaims l to 6;

   a control part that changes the brightness of the sub headlight light source in accordance with the lean angle of the vehicle; and a détection part that detects a variable available for obtaining the lean angle of the vehicle, wherein, when the lean angle of the vehicle leanmg to the one side with respect to the width direction of the vehicle reaches the reference value that is set for the sub headlight light source, the control part causes the sub headlight light source to light up with the first brightness, and in the period from when the lean angle of the vehicle reaches the lower value that is less than the reference value to when the lean angle of the vehicle reaches the reference value, the control part causes the sub headlight light source to light up with a brightness lower than the first brightness.

   [Claim 8]

   The sub headlight system according to claim 7, wherein the sub headlight system includes a voltage detector that detects a supply voltage value of a voltage that is supplied from a battery provided in the vehicle to the sub headlight light source,

   I the control part perforais:

   a comparison process for comparing the supply voltage value detected by the voltage detector against a reference voltage value ofthe battery; and an adjustment process for adjusting, based on a resuit of the comparison, the brightness of the sub headlight light source that changes in accordance with the lean angle of the vehicle.

   [Claim 9]

   The sub headlight system according to claim 8, wherein when the lean angle of the vehicle is in a range of at least the lower value and less than the reference value, the control part perforais the adjustment process, while when the lean angle ofthe vehicle is out ofthe range, the control part does not perforai the adjustment process.

   [Claim 10]

   A vehicle that leans into turns, the vehicle comprising the system according to any one of claims 7 to 9.

   [Claim 11]

   A method to control a sub headlight unit for use in a vehicle that leans into turns, with a sub headlight light source, wherein the sub headlight light source illuminâtes, at one side with respect to a width direction of the vehicle, an area ahead and outward of the vehicle with respect to the width direction of the vehicle, the brightness of the sub headlight light source changes in accordance with a lean angle of the vehicle, when the lean angle of the vehicle Ieaning to the one side with respect to the width direction of the vehicle reaches a reference value that is set for the sub headlight light source, the sub headlight light source lights up with a first brightness, and in a period from when the lean angle of the vehicle reaches a lower value that is less than the reference value to when the lean angle of the vehicle reaches the reference value, the sub headlight light source lights up with a brightness lower than the first brightness.

   [Claim 12]

   A method to control a sub headlight unit for use in a vehicle that leans into turns, with a sub headlight light source according to claim 11, wherein when the lean angle of the vehicle reaches the lower value that is set for the sub headlight light source, an illumination range of the sub headlight light source contains a space above a horizontal line, l

   <

   * when the lean angle of the vehicle reaches the reference value that is set for the sub headlight light source, the illumination range of the sub headlight light source is located in a space below the horizontal line.

   [Claim 13]

   A method to control a sub headlight unit for use in a vehicle that leans into turns, with a sub headlight light source according to claim I2, wherein a cut-off line of the sub headlight light source obtained when the lean angle of the vehicle reaches the reference value that is set for the sub headlight light source is doser to horizontal than the cut-off line of the sub headlight light source obtained when the lean angle of the vehicle reaches the lower value that is set for the sub headlight light source.

   [Claim I4]

   A method to control a sub headlight unit for use in a vehicle that leans into turns, with a sub headlight light source according to claim 13, wherein the reference value and the lower value are individually set for each of a plurality of sub headlight light sources, the reference value of one sub headlight light source is equal to or smaller than the lower value of another sub headlight light source for which the next greatest reference value aller that of the one sub headlight light source is set.

   [Claim 15]

   A method to control a sub headlight unit for use in a vehicle that leans into turns, with a sub headlight light source according to claim 14, wherein an optical axis of the sub headlight light source is fixed, the sub headlight light source whose optical axis is fixed lights up with the first brightness when the lean angle of the vehicle reaches the reference value that is set for the sub headlight light source, and lights up with a brightness lower than the first brightness in the period front when the lean angle of the vehicle reaches the lower value thaï is less than the reference value to when the lean angle of the vehicle reaches the reference value.