JPH0637155B2 - Illumination angle adjustment device for vehicle headlights - Google Patents

Abstract

PURPOSE:To reduce the number of connecting wires by producing an output signal in accordance with a difference between a set voltage which is set depending upon a take-out position of partial voltage and a reference voltage which is taken out from a reference resistance means applied with a power source voltage so as to change the illuminating angle. CONSTITUTION:The partial voltage of a set voltage take-out resistance 41 applied at its both ends with the voltage of a power source 3 is changed over by means of a manipulating means 42 in a set voltage take-out circuit 4 so as to extract a set voltage which is delivered to a reference comparing circuit 52. Comparators CP1 through CP4 compares the set voltage with reference voltages which are partial voltages V1 through V4 taken out from a reference voltage setting resistor 51, and an output signal generating circuit 53 produces an output signal so that an illuminating angle changing circuit 54 drives a d.c. motor 46 in a normal or reverse direction in order to obtain an illuminating angle corresponding to the set voltage. In this arrangement the number of connecting lines led out from the set voltage take-out circuit 4 on the passenger compartment side is only three, that is, only wires La, Lb, Lc are led out. Thus it is possible to reduce entrance of noise through a wire through-hole, and to facilitate the water-proof measure.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention is intended to adjust the irradiation angle of a headlamp that is tiltably held with respect to a vehicle body in multiple stages from a driver's seat side by remote control. The present invention relates to a vehicle headlight irradiation angle adjusting device that is suitable for use.

[Conventional technology]

In vehicles, especially automobiles, the body and the axle are leaf springs,
Due to the fact that they are connected by a suspension system consisting of coil springs, etc., when a large load is applied to the front wheel or rear wheel side of the vehicle body, the posture of the vehicle body will be in the state of front sunk or rear sunk, and accordingly the headlamp The vertical irradiation angle with respect to the road surface is changed to impair driving safety, and there is a danger that the driver of an oncoming vehicle may be significantly dazzled if the headlight is directed upward due to rearward sinking.

In order to correct such a change in the irradiation angle of the headlight with respect to the road surface, the headlight is held tiltably with respect to the vehicle body, and the irradiation angle of the headlight is remotely controlled from the driver side. A device constructed so that it can be adjusted by
It is disclosed in Japanese Patent No. 46733. FIG. 5 shows this Japanese Patent Laid-Open No.
It is a figure which shows the operation principle of the irradiation angle adjustment apparatus disclosed by the 1-46733 gazette, and was hold | maintained tiltably with respect to a vehicle body by switching the connection mode of the operation switch 1 arrange | positioned at the driver's seat side. It is intended to adjust the irradiation angle of the front light (not shown).

That is, by switching the connection mode of operation than illustrated state switch 1, for example When the common terminal 1 _-0 and and its switching terminal 1 _-5 connection state, sliding contacts 21d- conductor to the relay coil RL1 of the drive unit 2 Electric current flows through the route of pattern 22-sliding contact 21a, and this relay coil RL
The common terminal rl1c of the first normally open / normally closed contact rl1 and the normally open contact terminal rl1a are electrically connected. This normally open / normally closed contact rl
Due to conduction between the first common terminal rl1c and its normally open contact terminal rl1a, a current flows in the direction A in the DC motor 24, and the motor 24 rotates forward to rotate the lamp drive shaft 25 clockwise in the figure. By rotating the lamp drive shaft 25 to the right, the irradiation angle of the headlight moves upward and the conductor pattern 22
The sliding board 26 having the upper surfaces 23 and 23 formed on its upper surface rotates clockwise, the sliding contact 21d separates from the conductor pattern 22, the energization of the relay coil RL1 is released, and the normally open / normally closed contact thereof is released. rl1 common terminal rl1c and normally open contact terminal rl1a
Are disconnected from each other, the power supply to the DC motor 24 is cut off, and the irradiation angle of the headlamp is fixed at a predetermined position in the upward direction.

When the connection mode of the operation switch 1 is switched from this state to the original state, that is, when the common terminal 1 _-0 and the switching terminal 1 _-4 are connected, the relay coil RL2 of the drive unit 2 is slid. Moving contact 21e-conductor pattern 2
3-A current flows through the path of the sliding contact 21i, the common terminal rl2c and the normally open contact terminal rl2a of the normally open / normally closed contact rl2 of the relay coil RL2 become conductive, and the direct current motor 24 moves in the direction B in the drawing. An electric current flows and the motor 24 rotates in the reverse direction,
The lamp drive shaft 25 rotates counterclockwise and the irradiation angle of the headlight moves downward.

That is, as can be seen from the above description, by switching the connection mode of the operation switch 1 to its switching terminals 1 _-1 to 1 _-7 , it is possible to remotely adjust the irradiation angle in seven stages in the vertical direction.

[Problems to be solved by the invention]

However, according to such a conventional irradiation angle adjusting device for a vehicle headlamp, there is a problem that the number of connecting lines between the operation switch and the drive unit increases as the number of adjusting steps of the irradiation angle increases. That is, in the case of the irradiation angle adjusting device shown in FIG. 5, seven connection lines L1 to L7 are required between the operation switch 1 and the drive unit 2 in order to adjust the irradiation angle in seven steps. Since the drive unit 2 is attached to the headlight and arranged in front of the vehicle, the holes (wiring holes) through which the connection lines L1 to L7 pass are defined as the engine room (outside of the vehicle) and the driver's seat side (inside of the vehicle). Must be largely opened in the partition section. That is, if the number of connecting lines between the operation switch and the drive unit increases, the wiring through-holes formed in the partition will increase accordingly.
There is a problem that the noise in the engine room introduced into the vehicle through the wiring passage hole increases.

Further, due to the increase in the number of connecting lines between the operation switch and the drive unit, waterproof measures against rainwater or the like that is guided to the inside of the vehicle through the above connecting lines from the headlamps arranged outside the vehicle (for example, It is very troublesome to pass each bushing through a small-sized bush hole in each large-sized bushing), and the wiring work is also difficult.

[Means for solving problems]

The present invention has been made in view of such a problem, and a divided voltage of a different value is set as a set voltage by switching the extraction position of the divided voltage with respect to the resistance means having a power supply voltage applied to both ends thereof. And take it out as
The divided voltage taken out from the reference resistance means having the power supply voltage applied to both ends thereof is set as the reference voltage, and the reference voltage and the set voltage are not compared, and the comparison between the reference voltage and the set voltage is made. Based on the result, an output signal according to the comparison result is generated, and the irradiation angle of the headlight in the vehicle is changed to a position determined according to the generated output signal.

[Action]

Therefore, according to the present invention, by disposing the resistance means inside the vehicle and deriving the set voltage taken out from the resistance means to the outside of the vehicle, the number of connection lines drawn to the inside of the vehicle is at least at both ends of the resistance means. It is possible to use a total of three power supply voltage lines to be applied and lead lines for the set voltage.

〔Example〕

Hereinafter, the irradiation angle adjusting device for a vehicle headlamp according to the present invention will be described in detail. FIG. 1 is a circuit configuration diagram showing an embodiment of this irradiation angle adjusting apparatus. In the figure, 4 is a set voltage extracting circuit arranged on the driver's seat side, and 5 is a drive unit attached to a headlight (not shown) held so as to be tiltable with respect to the vehicle body.

The set voltage extracting circuit 4 is composed of a set voltage extracting resistor 41 formed by connecting resistors R1 to R4 in series and a rotary type operation switch 42.
The power supply voltage (DC 12V) of the vehicle-mounted battery 3 is applied to both ends of the. That is, one end of the set voltage extraction resistor 41 is connected to the positive polarity side of the vehicle-mounted battery 3 via the power input terminal 4 a, and the other end is body-grounded in the set voltage extraction circuit 4. Then, a connection point between the resistor R1 and the power input terminal 4a, a connection point between the resistors R1 and R2, a connection point between the resistors R2 and R3, a resistor R3 and a resistor R
The switching terminals 42 _-1 , 42 _-2 , 42 _-3 , 42 _-4 and 42 _-5 of the operation switch 42 are connected to the connection point of the operation switch 42 and the installation connection point of the resistor R4. The terminal 42 _-0 is connected to the drive unit 5 via its output terminal 4b.
Is connected to the signal input terminal 5b. The resistors R1 to R4 in the set voltage extracting resistor 41 are set to have the same resistance value (R1 = R2 = R3 = R4 = RΩ), and therefore the switching terminals 42 ₋₁ , 42 ₋₂ , 4 of the operation switch 42.
2 _-3 , 42 _-4 and 42 _-5 have a set voltage output resistance 41
DC voltage of 12V, 9V, 6V, 3V and 0V is generated as the divided voltage of.

On the other hand, the drive unit 5 includes a reference voltage setting resistor 51 formed by connecting resistors R5 to R9 in series, and a comparator CP1.
To CP4, an output signal generation circuit 53 including EX-OR circuits (hereinafter abbreviated as EX) 531 to 534 and a transistor array ( _Tr array) 535, and generation of the output signal generation circuit 53. It is composed of an irradiation angle variable circuit 54 for changing the irradiation angle of the headlight at a position determined according to the output signal to be output, and a fail-safe circuit 55. Is being applied. That is, one end of the reference voltage setting resistor 51 is connected to the positive side of the vehicle-mounted battery 3 via the power input terminal 5a, and the other end is grounded in the drive unit 5. Then, the divided voltages V1 and V2 extracted from the connection point between the resistors R5 and R6, the connection point between the connection R6 and the resistance R7, the connection point between the resistance R7 and the resistance R8, and the connection point between the resistance R8 and the resistance R9. , V3 and V4 are used as reference voltages for the comparators CP1, CP2, CP3 in the voltage comparison circuit 52.
And CP4 to the inverting input terminal. At the non-inverting input terminals of the comparators CP1, CP2, CP3 and CP4, the divided voltage extracted from the common terminal 42 _-0 of the operation switch 42 in the set voltage extracting circuit 4 is set via the fail safe circuit 55 to the set voltage V _IN. Is entered as. The fail-safe circuit 55 includes a protection resistor R10 connected between the non-inverting input terminals of the comparators CP1 to CP4 and the signal input terminal 5b of the drive unit 5, the resistor R10 and the comparators CP1 to CP1.
It is composed of a parallel circuit of a capacitor C and a resistor R11 connected between the connection point with the non-inverting input terminal of CP4 and ground, and the charging load of the capacitor C gradually increases with respect to the resistor R11 during the discharging state. Resistor R11 to discharge
The value of is set large enough. The resistors R5 to R9 in the reference voltage setting resistor 51 are the resistors R6, R7, and R8 in the set voltage extracting resistor 41.
Is set equal to 4 (R6 = R7 = R8 = R
Ω), the resistor R5 and the resistor R9 are these resistors R6 to R8.
Is set to 1/2 of the resistance value of (R5 = R9 = R /
2Ω). Therefore, the comparators CP1, CP2, CP
3, the reference voltage set at the inverting input terminal of CP4 is V1
= 10.5V, V2 = 7.5V, V3 = 4.5V, V4 = 1.5V.

Then, the comparator CP1 in the voltage comparison circuit 52
Is output to one end of the EX531 as a signal (d) and to the transistor array 535 as a signal (i). Further, the output of the comparator CP2 is output as a signal (c) to the other end of the EX531 and the EX53.
2, so that the output of the comparator CP3 is input as the signal (b) to the other end of the EX532 and one end of the EX533, and the output of the comparator CP4 is input to the other end of the EX533 and the one end of the EX534 as the signal (a). Therefore, the "H" level signal is always input to the other end of the EX 534 via the pull-up resistor R _P1 . And EX531, 532, 533 and 53
Each output of No. 4 is input to the transistor array 535 as signals (h), (g), (f) and (e), and of the input signals, only the signal (e) is input. When it becomes "H" level, the transistor array 535 sets only its output terminal 535a to "L" level.
Further, when only the input signal (f) becomes the "H" level, only the output terminal 535b is not set to the "L" level, and in the same manner, only the signal (g) becomes the "H" level. If only the output terminal 535c becomes "H" level, the output terminal 535d only becomes output when the signal (h) becomes "H" level. Only the terminal 535e is set to the "L" level.

Then, the output terminal 53 of the transistor array 535
Sliding contacts 544b to 54e, 5a to 535e, which are in sliding contact with the semi-circular strip-shaped conductor patterns 542 and 543 formed on the sliding substrate 541 in the irradiation angle variable circuit 54.
4f, and the potential level generated at the sliding contacts 544a and 544g is the same as that at the input terminals 545a and 545.
It is input to the forward / reverse rotation motor driver 545 via b. And this forward / reverse rotation motor driver 5
When the signals of "L" and "H" level are input to 45 through the input terminals 545a and 545b, the DC motor 546 is transmitted through the forward / reverse rotation motor driver 545.
A drive current flows in the direction A in the figure, and the drive current causes the DC motor 546 to rotate positively to move the irradiation angle of the headlamp in the upward direction and the sliding substrate 541 to rotate right in the figure. There is. Further, when signals of “H” and “L” level are input to the forward / reverse rotation motor driver 545 via the input terminals 545a and 545b, the DC motor 546 is transmitted via the forward / reverse rotation motor driver 545.
A current flows in the direction B in the drawing, the DC motor 546 rotates in the reverse direction, the irradiation angle of the headlamp moves downward, and the sliding substrate 541 rotates in the left direction in the drawing.

The sliding contact 544a in the irradiation angle variable circuit 54
And 544g are connected to a high potential power supply via pull-up resistors R _P2 and R _P3 . Further, the body ground in the set voltage extraction circuit 4 and the body ground in the drive unit 5 (body ground in the reference voltage setting resistor 51) are connected via the ground terminal 4c of the set voltage extraction circuit 4 and the ground terminal 5c of the drive unit 5. Connected to each other.

Next, the operation of the irradiation angle adjusting device configured as described above will be described. That is, it is assumed that the connection mode of the operation switch 42 in the set voltage extracting circuit 4 is in the illustrated state, that is, the common terminal 42 _-0 and the switching terminal 42 _-3 are in the connection state. In this case, the _divided voltage extracted from the set voltage extracting resistor 41 via the common terminal 42 _-0 is 6
The divided voltage of 6V appears at the connection point between the resistor R10 and the capacitor C of the fail-safe circuit 55 in the drive unit 5, and this divided voltage is used as the set voltage V _IN for the non-inverting inputs of the comparators CP1 to CP4. Set on the edge. This set voltage V _IN of 6V allows comparator C
The output level of P1, CP2, CP3, CP4 is "L",
It becomes "L", "H", "H", and only the output level of the EX532 becomes "H". Therefore, only the output terminal 535c of the transistor array 535 becomes the “L” level,
In the illustrated state, since both the input signal levels of the input terminals 545a and 545b of the forward / reverse rotation motor driver 545 are “H”, the drive current is not supplied to the DC motor 546 through the forward / reverse rotation motor driver 545, and the headlight is not emitted. The irradiation angle of is maintained in the stopped state in the predetermined direction determined by the rotation angle position of the motor 546. In this embodiment, the irradiation angle at this time is the center position in the vertical direction with respect to the road surface.

From such a state, when the connection mode of the operation switch 42 in the set voltage extraction circuit 4 is switched and, for example, the common terminal 42 _-0 and the switching terminal 42 _-2 are connected, the common terminal 42 _-0 Set voltage output resistance 41
The divided voltage taken out from is 9 V, and this divided voltage of 9 V appears at the connection point between the resistor R10 and the capacitor C of the fail-safe circuit 55 in the drive unit 5,
This divided voltage is used as the set voltage V _IN for the comparator CP1.
Set to the non-inverting input terminal of CP4. By this set voltage V _IN of 9V, comparators CP1, CP2, CP3, C
The output level of P4 becomes "L", "H", "H", "H", and only the output level of EX531 becomes "H". Therefore, the output terminal 535d of the transistor array 535
Only becomes the “L” level, and the forward / reverse rotation motor driver 54
The input signal levels of the input terminals 545a and 545b of No. 5 become "L" and "H", and a drive current in the direction A flows to the DC motor 546 through the forward / reverse rotation motor driver 545. The rotation causes the irradiation angle of the headlight to start moving upward. on the other hand,
With the positive rotation of the DC motor 546, the sliding substrate 541 is
Rotates to the right, and the output terminal 53 of the transistor array 535
The sliding contact 544e connected to 5d is the conductor pattern 54.
3 is separated from the forward / reverse direction motor driver 545.
The input signal level to the input terminal 545a of is "H". That is, the input signal levels of the input terminals 545a and 545b of the forward / reverse rotation motor driver 545 are both "H".
And the forward / reverse rotation motor driver 5 for the DC motor 546
The supply of the drive current in the direction A via 45 is cut off. By stopping the motor by cutting off the supply of the drive current to the DC motor 546, the irradiation angle of the headlamp is fixed at a predetermined position in the upward direction.

In addition, the connection mode of the operation switch 42 in the set voltage extraction circuit 4 is switched to, for example, the common terminal 42 _-0.
When the switching terminal 42 _-4 and the switching terminal 42 _-4 are connected, the _divided voltage extracted from the set voltage extracting resistor 41 via the common terminal 42 _-0 becomes 3V, and the divided voltage of 3V is changed in the drive unit 5 by the divided voltage. It appears at the connection point between the resistor R10 and the capacitor C of the fail-safe circuit 55, and this divided voltage is set as the set voltage V _{IN at} the non-inverting input terminals of the comparators CP1 to CP4. The output voltage of the comparators CP1, CP2, CP3, CP4 becomes "L", "L", "L", "H" by this set voltage V _IN of 3V, and EX5
Only the output level of 33 becomes "H". Therefore, only the output terminal 535b of the transistor array 535 becomes "L" level, the input signal levels of the input terminals 545a and 545b of the forward / reverse rotation motor driver 545 become "H" and "L", and the forward / reverse rotation of the DC motor 546 is performed. A drive current in the B direction flows through the motor driver 545, the motor rotates in the reverse direction, and the irradiation angle of the headlight starts moving downward. On the other hand, when the sliding substrate 541 rotates counterclockwise with the reverse rotation of the DC motor 546 and the sliding contact 544c connected to the output terminal 535b of the transistor array 535 separates from the conductor pattern 542,
The signal level to the input terminal 545b of the forward / reverse rotation motor driver 545 becomes "H". That is, the input signal levels of the input terminals 545a and 545b of the forward / reverse rotation motor driver 545 both become "H", the DC motor 546 is stopped, and the irradiation angle of the headlamp is fixed at a predetermined position in the downward direction. .

The table (Table 1) shown below is a signal for the connection mode of the operation switch 42 in the irradiation angle adjusting device.
It is a truth table which shows the level change of (a)-(i). In the table, connection modes I to V show the connection states of the common terminal 42 _-0 and the switching terminals 42 _{-1 to} 42 _-5 of the operation switch 42.

As you can see from this truth table, operation switch 4
By appropriately switching the connection mode of No. 2, the “H” level positions of the signals (e) to (i) input to the transistor array 535 change according to the connection mode, and the signals are input to this transistor array 535. The irradiation angle of the headlight is moved and fixed to a position determined according to the "H" level position of the signals (e) to (i).

As described above, according to the irradiation angle adjusting apparatus of the present embodiment,
The set voltage extraction circuit 4 arranged on the driver's seat side and the drive unit 5 attached to the headlight are connected to three connection lines La to L.
Since it can be connected by c and the irradiation angle can be adjusted, it is possible to reduce the wiring through hole that is opened in the partition between the engine room and the driver's seat side, and the wiring through hole can be guided inside the vehicle. It becomes possible to suppress the noise in the engine room which is generated. Further, since the number of connection lines is small, it is possible to easily take waterproof measures against rainwater or the like which is guided to the inside of the vehicle from the headlights arranged outside the vehicle and which is guided to the inside of the vehicle, and the wiring work is also facilitated. In this embodiment, the ground terminal 4c of the set voltage extracting circuit 4 and the ground terminal 5c of the drive unit 5 are connected by the connection line Lc.
Since c is individually body-grounded in the set voltage extraction circuit 4 and the drive unit 5, it is not always necessary. If the connection line Lc is omitted, the number of connection lines drawn into the vehicle interior can be further reduced to two. However, when the body ground is independently provided, the ground potential differs depending on the place where the body ground is taken. In some cases, the set voltage output circuit 4
It is desirable that the ground line of the drive unit 5 and the ground line of the drive unit 5 are connected to each other by a connection line Lc.

Further, in the present embodiment, the set voltage V _IN to the voltage comparison circuit 52 is set via the fail-safe circuit 55. Therefore, when switching the connection mode of the operation switch 42 in the set voltage extraction circuit 4. Even if the extraction of the divided voltage from the set voltage extraction resistor 41 is momentarily interrupted, the value of the set voltage V _IN to the voltage comparison circuit 52 is substantially before switching due to the charge level of the capacitor C in the fail-safe circuit 55. It is possible to obtain a stable irradiation angle switching operation, which is maintained at the value of. When the input of the divided voltage from the set voltage extracting resistor 41 to the drive unit 5 is interrupted for a long time due to disconnection of the connection line Lb or the like, the capacitor C in the fail-safe circuit 55 is stopped.
By gradually discharging the charged load of the battery through the resistor R11, the value of the set voltage V _IN to the voltage comparison circuit 52 becomes zero, and the operation switch 42 is moved to the maximum downward position according to the connection mode V. The illumination angle of the lamp gradually moves and is fixed. Therefore, even if the irradiation angle of the headlight is adjusted upward, even if a disconnection accident occurs in the connection line Lb, a predetermined time elapses determined by the discharge time constant of the capacitor C and the resistor R11 in the fail-safe circuit 55. After that, the irradiation angle of the headlight always moves downward and is fixed, and there is no danger of dazzling the driver of the oncoming vehicle.

Further, in this embodiment, the signals (a) to (d) sent from the voltage comparison circuit 52 are processed by the EX531 to 534,
Although it is configured to be input to the transistor array 535, the binary-hexadecimal decoder 536 as shown in FIG. 2 is used to process the signals (a) to (d) sent from the voltage comparison circuit 52. Good. The table (Table 2) shown below is a truth table showing changes in the input / output signals of the binary-hexadecimal decoder 536 depending on the connection mode of the operation switch 42.

Further, in the voltage comparison circuit 52 shown in FIG. 2, if the terminal positions of the non-inverting input terminals and the inverting input terminals of the comparators CP2 and CP3 are exchanged (see FIG. 3), the signal sent out by the voltage comparison circuit 52. (a) to (d) change according to the connection mode of the operation switch 42 as shown in the following table (Table 3), and as shown in FIG.
Binary-decimal decoder 537 can be used, binary-
As compared with the hexadecimal decoder 536, the package structure can be downsized.

As shown in FIG. 4, the voltage comparison circuit 52 is composed of open collector type comparators CP1a to CP4a, and pull-up resistors R _{P4 to} R _P7 are connected between the outputs of the comparators CP1a to CP4a and the high potential power source. Further, the outputs of the comparators CP1a to CP4a are input to the open collector type inverters INV1 to INV4, and if the transistor array 535 is wired as shown in the figure, the connection mode of the operation switch 42 is shown in the table below. The truth table shown in Table 4) is obtained. With such a configuration, it is possible to directly use the DC 12V power source in the output signal generation circuit 53,
An output signal whose breakdown voltage is higher than that of the output signal generation circuit using the decoder 536 and the decoder 537 shown in FIG. 2 and FIG. 3 (decoder generally uses 5V DC) and which is resistant to voltage noise. It can be a generation circuit.

In each of the above-described embodiments, the forward / reverse rotation motor driver 545 is used to drive the DC motor 546 to switch its rotation direction. However, the driving method using a relay shown in FIG. Needless to say, it may be adopted. In addition, in the present embodiment, the irradiation angle of the headlight is adjusted by manually operating the operation switch 42 in the set voltage extraction circuit 4. However, for example, a sensor signal from a tilt angle sensor is received. Alternatively, the connection mode of the operation switch 42 may be automatically switched to adjust the irradiation angle of the headlight. Further, in the present embodiment, the irradiation angle of the headlight in the vertical direction is adjusted, but it is also possible to apply to adjustment of the irradiation angle of the headlight in the horizontal direction. There is no end.

〔The invention's effect〕

As described above, according to the irradiation angle adjusting device for a vehicle headlamp of the present invention, different values of different values can be obtained by switching the extraction position of the divided voltage with respect to the resistance means that applies the power supply voltage to both ends thereof. The pressure voltage is taken out as the set voltage, and the divided voltage taken out from the reference resistance means formed by applying the power supply voltage across the set voltage is set as the reference voltage, and this reference voltage is compared with the set voltage. On the basis of the comparison result of the reference voltage and the set voltage, an output signal corresponding to the comparison result is generated, and the irradiation angle of the headlight in the vehicle is changed to a position determined according to the generated output signal. Therefore, if the resistance means is arranged inside the vehicle and the set voltage taken out from the resistance means is led to the outside of the vehicle, the number of connection lines drawn into the inside of the vehicle can be reduced. It is possible to have a total of three power supply voltage lines applied to both ends of the resistance means and lead lines for the set voltage, and the wiring through hole from the vehicle exterior side to the vehicle interior side can be made smaller so that It is possible to suppress noise in the engine room that is guided inward. In addition, since the number of connection lines is small, it is easy to take waterproof measures against rainwater or the like that is led from the headlights arranged outside the vehicle to the inside of the vehicle through the connection lines, and the wiring work is also easy. It has an excellent effect.

[Brief description of drawings]

FIG. 1 is a circuit configuration diagram showing an embodiment of an irradiation angle adjusting device for a vehicle headlamp according to the present invention, and FIGS. 2 to 4 are other circuits in a drive unit of the irradiation angle adjusting device. FIG. 5 is a diagram showing a configuration example, and FIG. 5 is a diagram showing an operation principle of a conventional irradiation angle adjusting device. 3 ... Battery, 4 ... Set voltage extraction circuit, 41 ... Set voltage extraction resistance, 42 ... Operation switch, 5 ... Driving unit, 51 ... Reference voltage setting resistance, 52 ... Voltage comparison circuit, 53 ... ... Output signal generation circuit, 54 ... Irradiation angle variable circuit, 55 ... Fail-safe circuit, La to Lb ... Connection line.

Claims (1)

[Claims] 1. Set voltage extracting means for extracting a divided voltage having a different value as a set voltage by switching the extracting position of the divided voltage with respect to a resistance means having a power supply voltage applied to both ends thereof, and to both ends thereof. The reference voltage setting means for setting the divided voltage taken out from the reference resistance means to which the power supply voltage is applied as the reference voltage, the reference voltage set by the reference voltage setting means and the set voltage taken out by the set voltage taking means. A voltage comparison means for comparison, an output signal generation means for generating an output signal according to the comparison result based on the comparison result in the voltage comparison means, and a vehicle at a position determined according to the output signal generated by the output signal generation means. And an irradiation angle changing means for changing an irradiation angle of the headlight in the vehicle headlight.