JPH0228111Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention is an optical axis adjustment device for a headlight that automatically adjusts the optical axis according to the inclination when the vehicle body is tilted and the optical axis is shifted. It is related to.

[Conventional technology]

For example, when the load on the rear of the vehicle increases, the optical axis of the headlights points higher than the appropriate position, dazzling oncoming vehicles and insufficiently illuminating the road surface.
An optical axis adjustment device that automatically corrects this has been proposed. (Refer to JP-A-59-26339.) However, the optical axis adjustment device disclosed in JP-A-59-26339 detects the inclination of the vehicle body and the direction of the optical axis using a potentiometer. Since this method compares the output voltages of the two, it lacks durability and is prone to errors due to changes in power supply voltage, ambient temperature, voltage drop in wiring, etc. In addition, the optical axis adjustment device described above is configured to always operate when the ignition switch is closed, so it is unnecessary even if the vehicle body is temporarily tilted due to the slope or unevenness of the road surface. There is a problem that optical axis adjustment is performed.

In order to prevent unnecessary optical axis adjustment as described above, it has been proposed to prohibit driving of the optical axis adjustment motor while the vehicle is running (see Japanese Patent Laid-Open No. 59-63243). ).

[The problem that the idea aims to solve]

According to the device described in Japanese Patent Application Laid-Open No. 59-63243, when the vehicle body is temporarily tilted due to the slope or unevenness of the road surface while the vehicle is running, unnecessary optical axis adjustment is not performed.

However, since this proposal controls the optical axis adjustment device by focusing on whether the vehicle is moving or stopped, unnecessary light is emitted when the vehicle is temporarily stopped due to waiting at a traffic light or in a traffic jam on a slope. There is a problem in that the axis adjustment has not been performed and if the vehicle continues to drive, the optical axis adjustment will be upward or downward and the desired optical axis cannot be obtained unless the vehicle is stopped once on a flat road.

The present invention improves the problems of the prior art as described above, is durable, and always performs accurate adjustment even when there are changes in power supply voltage and temperature, as well as slight voltage drops due to wiring, etc. It is an object of the present invention to provide an optical axis adjustment device for a headlamp that does not make unnecessary optical axis adjustment when driving or temporarily stopping on a slope.

[Means to solve the problem]

In order to achieve the above objects, the present invention includes a first encoder that outputs a gray code signal according to the inclination of the vehicle body, and a second encoder that outputs a gray code signal according to the change in the optical axis of the headlight. a first decoder that converts the output signal of the first encoder into a binary number; a second decoder that converts the output signal of the second encoder into a binary number; a latch circuit that holds an output signal; an arithmetic circuit that compares the output of the latch circuit with the output of the second decoder; a motor drive circuit that drives the motor according to the output of the arithmetic circuit; The timer circuit consists of an optical axis drive device that changes the optical axis direction of the headlight by driving, a door switch that turns off when the vehicle door opens and turns on when it closes, and a timer circuit that starts timing when the door switch is turned on. The invention is characterized in that the optical axis is adjusted by obtaining an output signal from the latch circuit and latching the latch circuit.

[Effect]

It is of course not possible to open or close the door of a vehicle while the vehicle is in motion, but when the vehicle is at a temporary stop such as waiting at a traffic light. The present invention focuses on this point, and uses a door switch that turns on when the door is closed, and a timer circuit that starts counting when the door switch is turned on, and latches the latch circuit only when the output signal of the timer circuit is obtained. Since this was done to adjust the optical axis, there is no need to make unnecessary optical axis adjustments while driving, but there is also no need to make unnecessary optical axis adjustments when waiting for a signal on a slope or in a traffic jam. I never do it.

〔Example〕

An example of implementing the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a circuit diagram showing an embodiment of the present invention. In FIG. 1, 1 is a first encoder that outputs a Gray code signal (also called a cyclic code signal) according to the inclination of the vehicle body, and 2 is a decoder that converts the Gray code signal of the encoder into a binary number. A latch circuit 3 holds the output signal of the decoder for a certain period of time using the output signal from the timer circuit 10. 4 is a second encoder that outputs a signal according to changes in the optical axis of the headlight; 5;
converts the Gray code signal of the second encoder into 2
This is a decoder that converts to a base number. A comparison circuit 6 compares the output signals of the latch circuit 3 and the second decoder 5, and outputs the result. 7
is a motor drive circuit which rotates the motor 8 forward or reverse according to the output signal of the comparison circuit. Reference numeral 8 denotes a drive motor for changing the optical axis, and an example of the optical axis driving device is shown in FIG. i.e. head lamp
The lamp bracket 13 that holds the HL is capable of freely tilting around a support point 14 fixed to the vehicle body at its lower part, and when the motor 8 rotates forward or reverse, the lamp bracket 13 is rotated through the reduction gear mechanism 11. By moving forward or backward a rod 12 connected to the upper part of the headlamp, the optical axis of the headlamp is changed, and the second encoder 4 is also changed in conjunction with this movement. Reference numeral 9 is a door switch, which is linked to the opening and closing of the vehicle door, and is turned off when the door is opened and turned on when it is closed. 1
0 is a timer circuit, and when the door switch is turned on, a trigger pulse is generated in a known trigger circuit consisting of resistors R ₃ , R ₄ , capacitor C ₂ and inverter circuit INV. 1, and timer 101 starts timing.
The base current flows through resistor _R5 to turn on transistor _Tr3 , and through resistor _R6 to turn on transistor Tr3.
A base current flows through Tr ₄ , turning on transistor Tr ₄ , and when timer 101 finishes counting, transistors Tr ₃ and Tr ₄ turn off. The connection point between the collector of the transistor Tr ₄ and the resistor R ₇ , that is, the output of the timer circuit 10, is "L" when the transistor Tr ₄ is off, and becomes "H" when the transistor Tr 4 is on. Relay contacts P ₁ , P ₂ and relay of the morke drive circuit 7
The power supplies for Ry ₁ and Ry ₂ are connected to the positive side of the battery 18 when the transistor Tr 4 is on, and are cut off when the transistor Tr ₄ is off. The latch circuit 3 latches the output signal of the first decoder 2 at the moment the output signal of the timer circuit 10 rises from "L" to "H",
It is held during "H". If the door is opened again for some reason immediately after closing the door (at this time, the timer 101 is still counting time), the output of the timer circuit 10 becomes "L", and the relay contact
Since P ₁ and P ₂ are cut off from the positive side of the battery 18, the motor 8 is stopped and the latch circuit 3 is unlatched. When the door is subsequently closed, the door switch 9 is turned on and the timer 101 starts counting (the timer 101 can be retriggered), and is configured to operate in the same manner as described above.

Next, the operation of the optical axis adjustment device according to the present invention will be explained.

When the load on the rear of the vehicle increases and the vehicle tilts, the optical axis of the headlights will point upwards from the correct position, causing dazzling to oncoming vehicles and insufficient illumination of the road surface. In order to prevent this, the device of the present invention works to automatically adjust the appropriate optical axis position. The device is pre-initialized in the proper position. When cargo (people) is loaded and the rear of the vehicle tilts, the position of the first encoder 1 changes,
A Gray code signal corresponding to that position is output. Since signal processing is difficult with Gray code, the signal is converted into a binary number by a decoder and input to the latch circuit 3. However, it is not latched in this state.

When loading is completed and the door is closed, the door switch 9 is turned on and the timer circuit 10 is activated as described above.
The output signal becomes "H", the input signal of the latch circuit 3 is latched, and becomes one comparison input (A input) of the comparison circuit (in this case, the magnitude comparison circuit) 6. On the other hand, the second encoder 4 is located at a position corresponding to the initial optical axis position, and the output of its Gray code signal is converted into a binary number by the second decoder 5, and the second encoder 4 is converted into a binary number by the second decoder 5. It is input (B input). Now the A input changes,
If it becomes larger, the A>B output terminal will be “H”
Then, base current flows through resistor R ₁ , transistor Tr ₁ is turned on, relay Ry ₁ is activated,
The contact _P1 switches, current flows to the motor 8,
The motor rotates in the normal direction, and the position of the optical axis changes toward the proper position (downward). At the same time the second encoder 4
As the position changes, its output signal also changes.
When the output signal of the latch circuit 3 and the output signal of the second encoder match, the A>B output terminal becomes “L”.
level, transistor Tr ₁ turns off, relay Ry ₁ becomes de-energized, and its contact P ₁ returns to its original state.
Motor 8 stops. The optical axis has now been adjusted to the appropriate position.

The time measured by the timer circuit is set in advance to be slightly longer than the time required for optical axis adjustment.
The magnitude comparison circuit 6 is provided with an A=B output terminal,
It is also possible to reset the timer 101 when A=B, that is, the optical axis is adjusted to a proper position and the two comparison inputs become equal. (Indicated by a broken line in the figure) Next, when the door is opened and the luggage (person) is unloaded, the rear of the vehicle returns to its original position, so the first encoder 1 returns to its original position, and the decoder 5 returns to its original position. The output signal of will also return to its original state.

When the door is closed after unloading is completed, door switch 9
is turned on from off, the output signal of the timer circuit 10 goes to the "H" level as described above, and the input signal of the latch circuit 3 is latched. Then,
Since the output signal of the latch circuit with the A input has become smaller than the output signal of the second decoder 5 with the B input, the A
<B output terminal becomes “H”, base current flows through resistor _R2 , transistor _Tr2 turns on,
Relay Ry ₂ is activated, contact P ₂ is switched, current flows to motor 8, motor 8 is reversed, the position of the optical axis changes to the proper position (upwards), and the position of the second encoder also changes. It's changing. When the output signals of the latch circuit 3 and the second decoder 5 match, A<B
The output terminal becomes "L", the transistor Tr ₂ is turned off, the relay Ry ₂ is de-energized, the contact P ₁ returns to its original state, and the motor 8 stops. The optical axis has now been adjusted to the appropriate position.

FIG. 3 shows another embodiment of the present invention. In this embodiment, encoders are provided at the front and rear of the vehicle.
In the case of a passenger car, the system also detects the inclination of the vehicle body when a person is sitting in the passenger seat, and adjusts the optical axis more appropriately. This embodiment is basically the same as the embodiment shown in FIG. It is a latch circuit that holds the output, 15,1
6 and 17 are encoder, decoder and latch circuits provided at the rear. Reference numeral 6 denotes an arithmetic circuit, which in this embodiment is composed of 61 subtracters and 62 magnitude comparison circuits. That is, by subtracting the output signals of the latch circuits 3 and 17 and calculating which one is larger, it is possible to determine whether the vehicle is tilted toward the front or the rear, and the output is as described in the first embodiment. Similarly, the optical axis is adjusted by comparing the output of the second decoder 5 with the output of the second decoder 5 to rotate the motor 8 in the forward or reverse direction.

[Effect of idea]

As mentioned above, the optical axis adjustment device of the present invention is
The use of a highly durable encoder and digital control system improves durability and allows accurate optical axis adjustment without being affected by changes in ambient temperature, current and voltage, or voltage drop between wiring. In particular, since the optical axis adjustment is performed only immediately after the door is closed, there is an effect that unnecessary adjustment is not performed not only while driving, but also when stopping temporarily on a slope.

In addition, according to the embodiment shown in FIG. 3, more appropriate optical axis adjustment can be performed by providing encoders at the front and rear.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing an example of the optical axis adjustment device of the present invention, FIG. 2 is a configuration diagram showing an example of the optical axis adjustment device, and FIG. 3 is a circuit diagram showing another embodiment. 1... First encoder, 2... First decoder, 3... Latch circuit, 4... Second encoder, 5... Second decoder, 6... Arithmetic circuit, 7
...Motor drive circuit, 8...Motor, 9...Door switch, 10...Timer circuit.

Claims (1)

[Scope of utility model registration request] A first encoder that outputs a gray code signal according to the inclination of the vehicle body, a second encoder that outputs a gray code signal according to the change in the optical axis of the headlight, and an output signal of the first encoder. a first decoder that converts the output signal of the second encoder into a binary number; a latch circuit that holds the output signal of the first decoder; and a latch circuit that holds the output signal of the first decoder. an arithmetic circuit that compares the output with the output of the second decoder; a motor drive circuit that drives a motor according to the output of the arithmetic circuit; and a light that changes the optical axis direction of the headlamp by driving the motor. It consists of a shaft drive device, a door switch that turns off when the vehicle door opens and turns on when it closes, and a timer circuit that starts counting when the door switch is turned on, and receives an output signal from the timer circuit to latch the latch circuit. An optical axis adjustment device for a headlamp, characterized in that it is designed to adjust the optical axis.