JPH061132A - Vehicle camber angle control device - Google Patents

Abstract

(57) [Summary] [Object] The present invention relates to a camber angle control device for a vehicle, and an object thereof is to be able to always maintain a constant steering force while adjusting the camber. [Structure] Steering wheels W1 and W2, and camber angle adjusting mechanisms 2 and 4 capable of adjusting the camber angles of the steering wheels W1 and W2.
Control means 32A for controlling the camber angle adjusting mechanisms 2 and 4
And a drive / braking state determination means 32B for determining the drive / braking state of the vehicle, and the control means 32A is configured to suppress a change in steering force due to driving or braking of the steered wheels W1, W2. A camber angle setting unit 32C that sets the camber angle according to the information from the driving / braking state determination unit 32B, and the camber angle adjusting mechanisms 2 and 4 based on the camber angle set by the camber angle setting unit 32.
And a control signal output unit 32D that outputs a control signal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a camber angle control device suitable for use in a vehicle suspension in which steered wheels are used as driving wheels, and more particularly to suppressing the influence of driving / braking of the vehicle on the steering force. The present invention relates to a vehicle camber angle control device that performs camber angle control.

[0002]

2. Description of the Related Art In automobiles, it is known that the traveling characteristics of the vehicle can be changed by adjusting the alignment of the suspension, and a camber angle (hereinafter also simply referred to as a camber) which is one of suspension elements.
Is also proposed to improve the running performance of the vehicle.

By the way, the steering characteristics of the vehicle can be changed by adjusting the alignment of the suspension of the front wheels, which are the steered wheels. For example, in order to improve the straight running stability of the vehicle, control may be performed such that the moment MK about the kingpin is large, and conversely, to improve the turning performance of the vehicle, control is performed such that the moment MK about the kingpin is small. You can do it.

The kingpin rotation moment MK can be increased by, for example, adjusting the caster angle to increase the caster trail, or adjusting the camber angle to set the ground kingpin offset d to a negative state. Conversely, the kingpin rotation moment MK can be reduced by adjusting the caster angle to reduce the caster trail, or adjusting the camber angle to make the kingpin offset d to ground 0 or positive.

When the front wheels, which are steered wheels, are drive wheels, that is, in a vehicle such as a front-wheel drive vehicle or a four-wheel drive vehicle, the kingpin moment MK changes according to the driving / braking state of the front wheels. For example, FIG. 9 shows a change in the kingpin moment MK that occurs according to the driving / braking state of the wheels under a constant caster trail.
The greater the driving or braking of the wheel, the smaller the kingpin-rotating moment MK. When the driving or braking becomes extremely large, the kingpin-rotating moment MK sharply decreases.

Further, FIG. 10 shows a change in the kingpin-rotating moment MK that occurs according to the driving / braking state of the wheels under a constant grounding kingpin offset d.
The greater the driving or braking of the wheel with respect to the ground kingpin offset d, the smaller the kingpin rotating moment MK, and when the driving or braking becomes extremely large, the kingpin rotating moment MK sharply decreases.

[0007]

By the way, when the front wheels which are the steered wheels are the drive wheels, the steering force also changes according to the driving or braking state of the wheels as described above. This change in the steering force is not preferable for the driving feeling of the automobile, and therefore there is a problem in that the steering force should always be kept constant.

As shown in FIG. 11, the characteristic of the steering force is in good agreement with the characteristic of the moment MK about the kingpin. Therefore, in order to keep the steering force constant, it suffices if the moment MK about the kingpin can be kept constant. The present invention has been devised in view of such a problem, and a camber angle control device for a vehicle that can always maintain a constant steering force while adjusting the camber so that the change in the moment around the kingpin is reduced. The purpose is to provide.

[0009]

Therefore, the vehicle camber angle control device of the present invention is a camber angle adjusting mechanism capable of adjusting the camber angle by driving the components of the steering wheel and the suspension of the steering wheel. And a control means for controlling the camber angle adjusting mechanism, and a drive / braking state determination means for determining whether the vehicle is in a driving state or a braking state, and the control means drives the steered wheels. Alternatively, a camber angle setting unit that sets the camber angle according to the driving / braking state based on information from the driving / braking state determination means so as to suppress a change in steering force due to braking, and a camber angle setting unit. A control signal output unit for outputting a control signal to the camber angle adjusting mechanism based on the set camber angle is provided.

In the vehicle camber angle control device of the present invention, it is preferable that the steered wheels are drive wheels.

[0011]

In the above-described vehicle camber angle control device of the present invention, the drive / braking state determining means determines whether the vehicle is in the driving state or the braking state. Then, the camber angle setting unit of the control means sets the camber angle according to the driving / braking state so as to suppress the change in the steering force due to the driving or braking of the steered wheels, based on the information from the driving / braking state determining means. After setting, the control signal output unit outputs a control signal to the camber angle adjusting mechanism based on the camber angle set by the camber angle setting unit.

The camber angle adjusting mechanism adjusts the camber angle by driving the constituent elements of the suspension of the steered wheels based on the set camber angle.

[0013]

1 is a block diagram of a camber angle control device for a vehicle according to an embodiment of the present invention.
Is a block diagram showing the configuration of the main part thereof, FIG. 2 is a configuration diagram schematically showing the whole thereof, FIG. 3 is a front view showing a suspension equipped with the present apparatus, FIG. 4 is a flowchart explaining its operation, and FIG. Reference numeral 8 is a map relating to the setting of the control amount (correction coefficient) in the control of this device.

A vehicle provided with this camber angle control device is a front-wheel drive vehicle or a four-wheel drive vehicle, and at least the front wheels that are steered wheels are configured as drive wheels.
The vehicle camber angle control device is configured as shown in FIG. In FIG. 2, reference numeral 2 is an actuator (camber angle adjusting mechanism) that adjusts the camber angle of the left front wheel, 4 is an actuator (camber angle adjusting mechanism) that adjusts the camber angle of the right front wheel, and 6 is the camber angle of the left rear wheel. An actuator (camber angle adjusting mechanism) for adjusting, and 8 an actuator (camber angle adjusting mechanism) for adjusting the camber angle of the right rear wheel.

These actuators 2 to 8 are composed of hydraulic cylinders, and are specifically provided on the suspension as shown in FIG. 3, for example. That is, FIG.
1 is a front view of an automobile, in which an actuator A (= 2 to 8) is interposed between the upper end of a strut S of a strut type suspension and a vehicle body F, and the strut S is extended or contracted by the actuator A. The upper end position of the wheel is displaced in the vehicle width direction, whereby the camber θ of each wheel W can be adjusted.

Referring again to FIG. 2, the actuators 2, 4, 6 and 8 are electromagnetic control valves 10, 1 respectively.
2, 14, and 16 are driven.
The control valves 10, 12, 14 and 16 are connected to the pump 20 via the supply passage 18 and to the oil reservoir 24 via the discharge passage 22. The pump 20 is driven by an engine (not shown) or the like to suck the oil in the oil reservoir 24 and discharge it to the supply passage 18. An accumulator 26 is connected to the supply passage 18, and a reservoir 24 is connected to the supply passage 18 via a relief valve 28, whereby the supply passage 18 is kept at a set pressure.

The respective control valves 10, 12, 14 and 16 are controlled by the respective control signals from the drive circuit 30 to prevent the oil supply to and discharge from the actuators 2 to 8 and lock the first position, and the respective actuators 2. Up to 8 are respectively taken as a second position for supplying and discharging oil in a direction (positive camber direction) and a third position for respectively supplying and discharging oil in a direction in which each actuator 2-8 is contracted (negative camber direction). Is able to.

Therefore, in order to drive the current camber angle to the target camber angle, the control valves 10, 12, 14 and 16 in the first position are switched to the second position or the third position and the actuators 2 to 2 are operated. 8 is expanded and contracted so that when the target camber angle is reached, the drive circuit 3 is returned to the first position.
Control signals are sent from 0 respectively. If the control signal for changing the camber angle is not sent from the drive circuit 30, the control valves 10, 12, 14 and 16 are held in the first position.

Reference numeral 32 denotes a controller as a control means for outputting a control signal to the drive circuit 30. The controller 32 performs a predetermined program processing on the basis of a signal input from each sensor which will be described later, and then outputs to the drive circuit 30. The controller 32 outputs a control signal.
Has a camber angle setting unit (not shown) that sets the camber angle of each wheel and a camber angle control unit (not shown) that controls the actuator.

Therefore, in the controller 32, a ROM 34 storing the above-mentioned predetermined program and maps used for the program processing, an input circuit (not shown) for inputting an output signal from each sensor, and a program are provided. It has a CPU, a RAM and an output circuit for executing computations and processes, and an interface between these elements.

When each of the above-mentioned sensors is specifically raised, a stroke sensor (vehicle height sensor) 36 as vehicle height detecting means for detecting the vehicle height through the stroke of the suspension.
Alternatively, a steering sensor 38 as steering detection means for detecting a steering angle θ _H of a steering wheel (not shown), a vehicle speed sensor 40 for detecting a vehicle speed, and the left front wheel actuator 2
Sensor 42 for detecting the stroke position of the actuator 4, the displacement sensor 44 for detecting the stroke position of the actuator 4 for the right front wheel, the displacement sensor 46 for detecting the stroke position of the actuator 6 for the rear left wheel, and the actuator 8 for the rear right wheel 8. Sensor 48 for detecting the stroke position of the vehicle and lateral acceleration sensor 50 for detecting the lateral acceleration acting on the vehicle.
There is also a longitudinal acceleration sensor 51 for detecting longitudinal acceleration acting on the vehicle.

Although the vehicle height sensor 36 is provided for each wheel here, it is also possible to provide only one vehicle height sensor 36 for the vehicle. Then, the controller 32 adjusts the camber angle according to whether the driving wheels of the vehicle are in a driving state or a braking state and whether the vehicle is in a straight traveling state or a turning traveling state. A control portion (camber angle control means) 32A is provided. This camber angle control means (hereinafter abbreviated as control means) 32A
Drives the required wheel actuators (camber angle adjusting mechanisms) 2 to 8 to adjust the camber angle to bring the grounding kingpin offset d into a predetermined state.

Such a controller 32 has a portion configured as shown in the block diagram of FIG. 1, for example. That is, as shown in FIG. 1, the controller 32 includes control means 32A for controlling the camber angles of the front wheels W1 and W2, which are steered wheels and drive wheels, drive / braking determination means 32B, and straight / turning determination means. 32E is provided. In addition, the control means 32A includes a camber angle setting unit 3
2C and a control signal output unit 32D are provided.

The driving / braking judging means 32B receives the detection signal from the longitudinal acceleration sensor 51, and uses the detected longitudinal acceleration value G _FR as the judgment reference values G ₁ , -G ₁ (however,
G ₁ > 0) to determine whether the wheel is in a driving state or a braking state. That is, if the longitudinal acceleration value G _FR is G _FR ≧ G ₁ , it is determined that the wheel is in the driving state, and if G _FR ≦ −G ₁ , it is determined that the wheel is in the braking state, and G ₁ ≧ G _FR ≧ -G ₁ (that is, G _FR ≤ | G
_{If 1} |), the wheels are judged to be neither in the driving state nor in the braking state.

Here, when G ₁ ≧ G _FR ≧ −G ₁ , it is determined that the wheel is neither in the driving state nor in the braking state, and the driving / braking control is not substantially performed as described later. . This is equivalent to providing a so-called dead zone,
This is intended to stabilize the control. The straight-ahead / turning determination means 32E receives the detection signal from the steering sensor 38, compares the detected steering angle value θ _H with the determination reference value δ ₁ (where δ ₁ > 0), and the vehicle It is determined whether the vehicle is in a straight traveling state or in a turning state. That is,
If the magnitude | θ _H | of the steering angle value θ _H is | θ _H | <δ ₁ , it is judged that the vehicle is in a straight traveling state, and if | θ _H | <δ ₁ (if | θ _H | ≧ δ ₁ For example, it is determined that the vehicle is turning.

In this case, the steering angle range for determining the straight traveling state is | θ _H | <δ ₁ (that is, −δ ₁ <θ _H <
δ ₁ ) is set to a constant width, but this is intended to stabilize the control by considering the play of the steering wheel and controlling the turning of a small rudder angle to be almost straight. This is because. The camber angle setting unit 32C of the control means 32A receives the judgment information from the driving / braking judgment means 32B and the straight / turning judgment means 32E and sets the camber angle φ. That is, the camber angle setting unit 32C
Then, the reference camber angle φ ₀ is corrected according to the driving / braking state (driving / braking correction) and the correction according to the straight traveling / turning state (straight traveling / turning correction) is performed to determine the camber angle φ. It is supposed to do. That is, the camber angle φ is determined according to the following equation (1).

Φ = K × K ′ × φ ₀ (1) The driving / braking correction in the camber angle setting unit 32 C is performed by the magnitude of the longitudinal acceleration G _FR detected by the longitudinal acceleration sensor 51.
The correction coefficient K is set corresponding to G _FR |, and this is multiplied by the reference camber angle φ ₀ . For example, when the wheel is in the driving state, the correction coefficient K is set in correspondence with | G _FR | using the map a as shown in FIG. When the wheel is in the braking state, the correction coefficient K is set corresponding to | G _FR | using the map b as shown in FIG. When the wheel is neither in the driving state nor in the braking state, the correction coefficient K is set to 1 and substantial driving / braking correction (that is, driving / braking control) is not performed.

Note that the map a is | G _FR | (this map a is in the driving state and G _FR > 0, so | G _FR | = G
_The correction coefficient K is set to gradually increase in accordance with an increase in ( _FR ), and in particular, the correction coefficient K is set to rapidly increase when | G _FR | (= G _FR ) becomes extremely large. Further, the map b shows that the correction coefficient K gradually decreases in accordance with the increase of | G _FR | (this map b is in the driving state and G _FR <0, so | G _FR | = −G _FR ). The correction coefficient K is set to abruptly decrease when | G _FR | (= − G _FR ) becomes extremely large.

The setting of such a correction coefficient K is for suppressing the change of the steering force according to the driving or braking state of the wheels. Below, the map a,
The reason for configuring b will be described. That is, in the vehicle of this embodiment, the grounding kingpin offset d is set to a negative value (for example, about −30 mm) in order to ensure the stability of the vehicle during braking, and the reference camber angle φ ₀ is set to this value. It is set to be realized.

However, as shown in FIG. 10, if the grounding kingpin offset d is kept constant (normally, it is constant unless there is a corresponding control of the suspension), the kingpin is changed according to the driving or braking state of the wheels. The turning moment MK changes. For example, when the ground kingpin offset d has a negative value (−30 mm), the greater the braking, the greater the moment MK, but the smaller the braking and the greater the driving, the smaller the moment MK. However, when driving or braking is extremely large, the moment MK decreases.

When the grounding kingpin offset d has a positive value (30 mm), the moment MK increases as the drive increases, but the moment MK decreases as the drive decreases or the braking increases. However, when driving or braking is extremely large, the moment MK decreases.
Further, when the ground kingpin offset d is 0 mm, the change of the moment MK is relatively small, but the moment MK becomes smaller as the driving becomes smaller and the braking becomes larger. If the driving or braking is extremely large, the moment MK decreases.

By the way, the characteristic of the steering force is in good agreement with the characteristic of the moment MK about the kingpin as shown in FIG. Therefore, in order to keep the steering force constant, it suffices if the moment MK about the kingpin can be kept constant. Thus, the moment M about the kingpin
In order to keep K constant, the grounding kingpin offset d may be increased during driving and the grounding kingpin offset d may be decreased during braking. Further, when driving or braking becomes extremely large, the grounding kingpin offset d may be rapidly increased during driving, and the grounding kingpin offset d may be rapidly decreased during braking.

However, as can be seen from FIG. 10, in order to keep the kingpin moment MK at a relatively small value, it is not necessary to greatly adjust the grounding kingpin offset d to around 0 mm. However, to keep the kingpin moment MK at a relatively large value,
It is necessary to greatly adjust the grounding kingpin offset d.

This grounding kingpin offset d can be adjusted by changing the camber angle. In the actuators (camber angle adjusting mechanism) 2 to 8 of this device, when the camber angle is increased, the center of contact with the road surface of the tire moves outward, and the grounding kingpin offset d is changed. For example, if the ground kingpin offset d is positive (positive kingpin offset), increasing the camber angle increases the ground kingpin offset d, but if the ground kingpin offset d is negative (negative kingpin offset), the camber angle is increased. Is increased, the magnitude of the ground kingpin offset d is decreased.

In the vehicle of this embodiment, since the negative kingpin offset is set in the standard state, increasing the camber angle decreases the magnitude of the grounding kingpin offset d (however, the negative kingpin offset is a negative value). Therefore, the negative kingpin offset value itself increases, that is, approaches positive).

Therefore, the moment M about the kingpin is
In order to keep K constant, when driving, the camber angle is increased as the driving is larger, and the ground kingpin offset d is increased, and when the braking is larger, the camber angle is decreased as the braking is increased. The kingpin offset d may be reduced. Further, when driving or braking becomes extremely large, the grounding kingpin offset d may be rapidly increased during driving, and the grounding kingpin offset d may be rapidly decreased during braking.

Therefore, at the time of driving, as shown in the map a shown in FIG. 5, the correction coefficient K is gradually increased in accordance with the increase of the longitudinal acceleration | G _FR | (= G _FR ) corresponding to the driving magnitude. By doing so, the camber angle is increased, and when | G _FR | becomes extremely large, the correction coefficient K is suddenly increased to rapidly increase the camber angle. Further, at the time of braking, as shown in a map b in FIG. 6, the correction coefficient K is increased according to the increase in the magnitude of the longitudinal acceleration | G _FR | (= − G _FR ) corresponding to the magnitude of the braking.
Is gradually decreased to decrease the camber angle, and when | G _FR | becomes extremely large, the correction coefficient K is rapidly decreased and the camber angle is rapidly decreased.

Note that a map c as shown in FIG. 7 may be used instead of the maps a and b. This map c is a combination of the maps a and b, and the correction coefficient K is set in correspondence with the longitudinal acceleration G _FR (value in which positive / negative is taken into consideration). Incidentally, in this map c, a portion corresponding to a so-called dead zone is not provided, but in the vicinity of G _FR = 0, K = 1 is fixed in an appropriate range (for example, a range of −G _{1 to} G ₁ ). If configured, a so-called dead zone will be provided.

For straight-ahead / turn correction in the camber angle setting section 32C, a correction coefficient K'is set in correspondence with the magnitude | G _Y | of the lateral acceleration G _Y detected by the lateral acceleration sensor 50,
This is done by multiplying the reference camber angle φ ₀ . In particular, | θ _H | <During straight running is [delta] _1, the ground kingpin offset close to zero and the correction to reduce the wheel sensitivity to road surface disturbance, | θ _H | <δ ₁
When the vehicle is not turning, the ground camber angle is corrected to be close to 0 to reduce the sensitivity of the wheel to the road disturbance.

In the vehicle of this embodiment, the ground kingpin offset reference value (non-correction value) is negative.
However, since the value itself is relatively close to 0, the correction coefficient K ′ is set to 0 and correction is not performed during straight traveling. On the other hand, during turning, the ground camber on the outer turning wheel side increases and the ground camber on the inner turning wheel side decreases, so the ground camber on the outer turning wheel side is corrected to decrease and the ground camber on the inner turning wheel side increases. To correct. That is, the correction coefficient K'is set to be smaller than 1 on the turning outer wheel side and is set to be larger than 1 on the turning inner wheel side.

The tendency of the increase or decrease of the ground camber becomes more remarkable as the turning becomes steeper, and it is generally considered to be proportional to the square of the magnitude of the lateral acceleration G _Y applied to the vehicle at the time of turning. Therefore, when turning, the correction coefficient K'is set using the map 1 in FIG. That is, the correction coefficient K ′ on the outer turning wheel side decreases in a quadratic curve with respect to the lateral acceleration G _Y , and the correction coefficient K ′ on the inner turning wheel side.
Increases quadratically with respect to the lateral acceleration G _Y.

Incidentally, here, the camber angle of the rear wheels is controlled by the correction according to the straight traveling / turning state. That is, the correction coefficient K '(may be different from that of the front wheels) is set as in the case of the front wheels, and the correction coefficient K'is set to the reference camber angle φ ₀ (also different from that of the front wheels. A) to determine the camber angle φ.

Since the vehicle camber angle control device as one embodiment of the present invention is constructed as described above, the camber angle is set for each wheel as shown in the flowchart of FIG. 4, for example. That is, first, immediately after the ignition switch of the automobile is turned on, etc., parameters related to control are initially set (step S1), and each sensor 3
The detection signals are read from 6 to 51 (step S2).

In the next step S3, the longitudinal acceleration sensor 5
The longitudinal acceleration value G _FR detected in 1 is used as a judgment reference value G ₁ ,
Compared with the -G _1. If G _FR ≦ −G ₁ , it is determined that the wheels are in the braking state, and the process proceeds to step S4, where G ₁ ≧ G _FR ≧ −
If G ₁ (that is, G _FR ≦ | G ₁ |), it is determined that the wheel is neither in the driving state nor in the braking state, and the process proceeds to step S5.
If G _FR ≧ G ₁ , it is determined that the wheels are in a driving state, and the process proceeds to step S6.

In step S4, the correction coefficient K is set corresponding to | G _FR | using the map b as shown in FIG. In step S5, the correction coefficient K is set to 1 so that the driving / braking correction is not substantially performed. In step S6, the correction coefficient K is set corresponding to | G _FR | using the map a as shown in FIG. When the correction coefficient K is set in this way, in the next step S7, the magnitude of the steering angle value θ _H detected by the lateral acceleration sensor 50 |
It is determined whether θ _H | is | θ _H | <δ ₁ .
If | θ _H | <δ _1, it is determined that the vehicle is in a straight traveling state, and the process proceeds to step S8. If | θ _H | <δ ₁ (| θ
_{If H} | ≧ δ ₁ , it is determined that the vehicle is in a turning state, and the process proceeds to step S9.

In step S8, the correction coefficient K'is set to 1 so that the vehicle of this embodiment does not substantially perform straight ahead / turning correction. Further, when proceeding to step S9, the correction coefficient K'is set corresponding to | G _Y | using the map 1 as shown in FIG. After setting the correction coefficients K and K'in this way, the next step S10
Then, as in the equation (1) above, the reference camber angle φ ₀ is multiplied by the correction coefficient K according to the driving / braking state and the correction coefficient K ′ according to the straight traveling / turning state to obtain the camber angle. Determine φ.

Then, in the next step S10, a control amount corresponding to the camber angle φ is set, and a control signal corresponding to the control amount is output to each actuator (camber angle adjusting means). As a result, due to the driving / braking correction, the grounding kingpin offset d increases due to the increase control of the camber angle during driving, and the grounding kingpin offset d decreases due to the decrease control of the camber angle during braking. Further, when driving becomes extremely large during driving, the grounding kingpin offset d sharply increases, and when braking becomes extremely large during braking, the grounding kingpin offset d sharply decreases. As a result, the kingpin moment MK is always controlled to be substantially constant.

Then, the moment M about the kingpin is
The steering force having a characteristic that closely matches the characteristic of K is held substantially constant, and an extremely good driving feeling with little change in the steering force can be obtained. Further, when traveling straight ahead, the grounding kingpin offsets d of both the left and right wheels are set to a value close to 0, and the steering characteristics are always stable against disturbance, improving the steering feeling and improving the driving performance of the vehicle. Can contribute to.

Furthermore, during turning, the increase in the ground camber of the turning outer wheel (positive) is suppressed, and the decrease of the ground camber of the turning inner wheel (negative) is suppressed, and the running stability of the vehicle is improved. Therefore, there is an advantage that the turning limit is increased. Incidentally, in this embodiment, by multiplying the correction coefficient K and K 'to the reference camber angle phi _0, but determines the camber angle phi, the driving based camber angle phi ₀ ·
It is also possible to add the correction amount according to the braking state and the correction amount according to the straight traveling / turning state to determine the camber angle φ.

Further, in this embodiment, the front wheels which are the steered wheels are the drive wheels, but it is conceivable to use the caster control even when the front wheels which are the steered wheels are the non-driving wheels. In this case, the driving / braking correction is mainly only the braking correction. The purpose of the caster control of this device is to adjust the casters so as to suppress the change of the steering force according to the driving / braking state. In particular, in this embodiment, the characteristic of the steering force is the kingpin rotation moment. The casters are adjusted so that the kingpin rotation moment MK does not change much, paying particular attention to the characteristics of MK. Therefore, if the change in steering force can be suppressed,
The control may be performed without considering the kingpin moment MK.

Further, in this embodiment, the case where the reference value (value at the time of no control) d ₀ of the grounding kingpin offset is set in the vicinity of −30 mm is explained, and each of the above maps (see FIGS. 5 to 8). ) Is an example set according to this setting and other characteristics of the vehicle. The ground kingpin offset reference value d ₀ can be set in various other ways. Based on various characteristic tendencies such as the setting of the ground kingpin offset reference value d ₀ and other characteristics of the vehicle, each of the above maps can be set. Various modes are conceivable (see FIGS. 5 to 8).

Further, the suspension provided with this vehicle camber angle control device is not limited to that of this embodiment, but can be applied to various suspensions, and the actuator itself as a camber angle adjusting mechanism is also of this embodiment. Not limited to. The essence of the caster control according to the driving / braking state does not change depending on the actuator configuration, but the specific control characteristics (how the actuator is specifically operated) differ from those of the embodiment. I think it will be.

[0053]

As described above in detail, according to the camber angle control device for a vehicle of the present invention, the camber angle can be adjusted by driving the steered wheels and the components of the suspension of the steered wheels. An adjusting mechanism and a control means for controlling the camber angle adjusting mechanism are provided, and a driving / braking state determining means for determining whether the vehicle is in a driving state or a braking state is provided. And a camber angle setting unit that sets the camber angle according to the driving / braking state based on information from the driving / braking state determination means so as to suppress a change in steering force due to driving or braking of the The steering force is always kept constant by the configuration in which a control signal output unit that outputs a control signal to the camber angle adjusting mechanism based on the camber angle set by the control unit is provided. Come to be, can improve the operation feeling of the vehicle, which contributes to improvement in running performance of the vehicle.

When the steered wheels are drive wheels, the above effects are particularly remarkable.

[Brief description of drawings]

FIG. 1 is a block diagram showing a main configuration of a vehicle camber angle control device as an embodiment of the present invention.

FIG. 2 is a configuration diagram schematically showing an entire vehicle camber angle control device as one embodiment of the present invention.

FIG. 3 is a front view showing a suspension provided with a vehicle camber angle control device as one embodiment of the present invention.

FIG. 4 is a flowchart illustrating an operation of a vehicle camber angle control device as an embodiment of the present invention.

FIG. 5 is a map relating to setting of a control amount (driving / braking correction coefficient) in the vehicle camber angle control device as one embodiment of the present invention.

FIG. 6 is a map relating to setting of a control amount (driving / braking correction coefficient) in the vehicle camber angle control device as one embodiment of the present invention.

FIG. 7 is a diagram showing a modification of the map relating to the setting of the control amount (driving / braking correction coefficient) in the vehicle camber angle control device as one embodiment of the present invention.

FIG. 8 is a map relating to setting of a control amount (straight ahead / turning correction coefficient) in the vehicle camber angle control device as one embodiment of the present invention.

FIG. 9 is a graph showing an example of characteristics of a moment about a kingpin relating to driving / braking according to a caster trail.

FIG. 10 is a graph showing an example of characteristics of a moment about a kingpin relating to driving / braking according to a ground kingpin offset.

FIG. 11 is a graph showing a comparison between a characteristic of a steering force and a characteristic of a moment about a kingpin.

[Explanation of symbols]

2, 4, 6, 8, A Actuator as camber angle adjusting mechanism 10, 12, 14, 16 Electromagnetic control valve 18 Supply path 20 Pump 22 Discharge path 24 Oil reservoir 26 Accumulator 28 Relief valve 30 Drive circuit 32 Control means Controller 32A control means 32B drive / braking determination means 32C camber angle setting section 32D control signal output section 32E straight-ahead / turning determination means 34 ROM in controller 32 vehicle height sensor 38 steering sensor (steering angle sensor) 40 vehicle speed sensor 42 , 44, 46, 48 Displacement sensor 50 Lateral acceleration sensor 51 Front-rear acceleration sensor F Car body S Strut-type suspension strut W Wheels W1, W2 Wheels (front wheels as steered wheels)

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Tadao Tanaka 5-3-8, Shiba, Minato-ku, Tokyo Mitsubishi Motors Corporation

Claims (2)

[Claims] 1. A steering wheel, a camber angle adjusting mechanism capable of adjusting a camber angle by driving a constituent element of a suspension of the steering wheel, and a control means for controlling the camber angle adjusting mechanism. The driving / braking state determination means for determining whether the vehicle is in the driving state or the braking state is provided, and the control means determines the driving / braking state so as to suppress a change in steering force due to driving or braking of the steered wheels. A camber angle setting unit that sets the camber angle according to the driving / braking state based on information from the means, and outputs a control signal to the camber angle adjusting mechanism based on the camber angle set by the camber angle setting unit. And a control signal output unit for controlling the camber angle control device for a vehicle. 2. The camber angle control device for a vehicle according to claim 1, wherein the steered wheels are drive wheels.