JPS635304B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a switch signal transmission device for an automobile, and more particularly to a switch signal transmission device for transmitting switch signals from various switches provided on a steering wheel of an automobile in the form of optical signals.

Conventional devices of this type include, for example, the
As shown in Japanese Patent Application No. 100266, there is known a system in which a switch signal provided on the steering wheel is transmitted to the vehicle body using an optical signal from a light emitting element that rotates integrally with the steering wheel.

However, in the above-mentioned publication, since the carrier lens means for receiving signals from the rotating light emitting element is formed in a cylindrical shape, there is a problem that the steering portion becomes large and installation is difficult. Moreover, since precise optical processing is required to condense the optical signals from the light emitting elements, the manufacturing cost is also high, which poses a major problem when put into practical use.

The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a switch signal transmission device for an automobile that is simple and inexpensive to manufacture and is capable of accurately transmitting switch signals.

For this reason, the present invention includes: a plurality of switches provided on a steering wheel of an automobile; an encoded signal that encodes a signal from each of the switches and outputs the encoded signal; a plurality of light emitting elements arranged at predetermined intervals on a circumferential plane so as to rotate together with the steering wheel; and each time the encoded signal is generated from the encoding circuit, the light emitting elements a light-emitting element drive circuit that causes all of the light-emitting elements to emit light and outputs an optical signal corresponding to the encoded signal; a plurality of light-receiving elements fixedly attached to the vehicle body side at predetermined intervals on a circumferential plane drawing concentric circles, and receiving optical signals from the light-emitting element and outputting a light-receiving signal; By calculating the logical sum of the light reception signals from the elements,
A logical sum circuit that outputs the result as a logical sum signal, and a load drive circuit that receives the logical sum signal from the logical sum circuit and drives the load mounted on the vehicle according to the operating state of each of the switches. With,
A configuration is adopted in which at least one of the light emitting element and the light receiving element is arranged at equal intervals.

The invention will now be described with reference to the accompanying drawings. FIG. 1 shows an example of the configuration of a multiplex signal transmission system according to the present invention. 1 is a steering handle, 2 is a part to which a light emitting element of the present system is attached, 3 is a part to which a light receiving element is also attached, 4 is a steering shaft, and 5 is a part fixed to the body consisting of a cover, a bearing, etc.

FIG. 2 is a diagram showing the arrangement of a light emitting element and a light receiving element. 11A to 11F are light emitting diodes,
There are 6 pieces lined up on the same circumference at equal intervals of 60°, and 1
2A and 12B are phototransistors, which are arranged on the same circumference with an angle of 90 degrees between them. The mounting parts 2 and 3 are respectively mounted with the shaft as the center as shown in FIG. 1, so that the surfaces constituted by 11A to 11F and 12A and 12B are parallel to each other, and the light emitting surface and the light receiving surface face each other.

FIG. 3 is an embodiment of the circuit diagram of the present invention. 2
0 is an encoder circuit that multiplexes signals. 2
2 is a turn right switch, 23 is a turn left switch, and 24 is a horn switch. 27 is a light emitting diode 11 according to the output of the encoder circuit 20.
Transistors A to 11F allow current to flow, and 26 is a resistor that limits the current flowing to the light emitting diode. 12A, 12B are phototransistors, 3
2 and 34 are load resistances of respective phototransistors, 31 and 33 are amplifier circuits, 35 is an OR circuit, and 30 is a drive circuit, which decodes multiplexed signals and follows the signals of switches 22, 23, and 24. This drives the turn right lamp 38, the turn left lamp 39, and the horn 40.

FIG. 4 shows the waveform of the multiplexed signal. Sb is the start bit, and b ₀ , b ₁ , and b ₂ are the turn right, turn left, and horn switch signals, respectively.

FIG. 5 shows the light emitting diode 11 in this embodiment.
A to 11F and phototransistors 12A and 12B
The relationship between the angle of deviation and the angle of deviation when the handle is rotated 360° is shown below. The solid line indicates a relative angular shift when the phototransistors 12A and 12B are logically summed by the function of the logical sum circuit 35.

6 and 7 show other embodiments, in which light emitting diodes 11A to 11F and phototransistors 12
An example is shown in which A and 12B are arranged concentrically around the steering shaft and on the same plane.

FIG. 8 shows the power supply circuit of this embodiment. 100 is a battery, 110 is a brush, 111 is a slip ring fixed to the steering wheel, 112
1 is a diode, 113 is a capacitor, 200 is a light emitting diode 11A to 11F in FIG.
The transmission side circuit attached to the steering wheel is composed of 0, 22, 23, 24, 26, and 27, and 300 is also a phototransistor 12.
A, 12B and 30, 31, 32, 33, 3
4, 35, 38, 39, and 40 are shown.

The operation of the present invention will be explained. In the embodiment shown in FIG. 2, six light emitting diodes 11A to 11F are arranged at 60 DEG intervals, and all output the same optical signal as shown in the connection diagram of FIG. 3. The phototransistors 12A and 12B that receive the optical signal are arranged with a 90 degree angle between them, and by amplifying the output and calculating the logical OR, if either phototransistor receives the signal, a normal signal is reproduced. can do.

Another light emitting diode 11A and a phototransistor 12A are in a straight line, and when you start turning the steering wheel to the right, 11A moves from 12A toward 12B, and 11B approaches 12B and 11A
When deviates from 12A by 30 degrees, 11B will be on a straight line with 12B. As you turn further to the right, 11A approaches 12B, 11B moves away from 12B, and 11F becomes 1.
Approaching 2A. In this case, phototransistors 12A, 12B and light emitting diodes 11A to 1
Figure 4 shows the deviation angle of 1F. Considering that the outputs of the phototransistors 12A and 12B are logically summed, the solid line indicates the smallest angle between any one of the six light emitting diodes and either one of the two phototransistors.
The table shows which light emitting diode corresponds to which phototransistor. The maximum deviation angle of the smallest set of deviation angles in this example is 15 degrees.

In order to reduce this deviation angle, it is sufficient to increase the number of light emitting diodes. When the number of light emitting diodes is N, the following relationship holds between the distance α° between the light emitting diodes, the distance β° between the two phototransistors, and the maximum deviation angle γ° of the set with the smallest deviation angle.

α=360°/N, β=3/2×α, γ=1/4×
α(1) If the light emitting diodes and phototransistors are arranged so as to satisfy the above relationship, it is possible to obtain substantially the same effect as using twice as many light emitting diodes.

FIG. 4 shows the waveform of the time division multiplexed signal of this embodiment. Horn switch 24, turn switch 22,
The switch signals No. 23 are multiplexed by the encoder circuit 20, as shown in Figure 4, after the start bit Sb, _b0 is assigned to the horn, _b1 is assigned to turn right, and _b2 is assigned to turn left. . The encoder circuit 20 transmits frames of the multiplexed signal having the above configuration at a constant cycle. b ₀ is 1, the horn switch is on, 0 is off, b ₁ is 1, the turn right switch is on, 0 is off, b ₂ is 1, the turn left switch is on, 0 is off It is. When the multiplex signal is 1, a current is applied to the light emitting diode. When phototransistors 12A and 12B receive light, they cause current to flow through the load resistor and generate a voltage across the load resistor. By amplifying the voltage and calculating the logical sum, it is possible to reproduce the original signal if the optical signal enters either one of the two phototransistors. Decoder circuit 30 decodes the multiplexed signal and drives a load corresponding to each switch.

FIG. 8 shows a method of supplying power to the circuit attached to the steering wheel. Power supply is battery 1
00 is attached to the steering wheel by a brush 110 and rotates integrally with the steering wheel, the current is applied to the circuit 200 through a diode 112, smoothed by a capacitor 113, and applied to the circuit 200. diode 1
12 and the capacitor 113, stable power can be applied to the circuit 200 even if there is a momentary contact failure between the brush and the slip ring.

In the present invention, horn, turn right, and turn left signals are transmitted, but by further increasing the number of bits, signals from lighting switches such as headlamps, and an auto drive system that allows the vehicle to drive at a constant speed even after releasing the accelerator are transmitted. It can transmit signals such as set/reset switches, auto search radio search switches, air conditioner switches, etc.

In this embodiment, all six light emitting diodes are connected in series, but three light emitting diodes may be connected in series or two in parallel, or each of the six light emitting diodes may be lit by a separate transistor and a limiting resistor.

Furthermore, in this embodiment, the light emitting element and the light receiving element are arranged on two concentric planes facing each other, but as shown in FIGS. 6 and 7, the light emitting element and the light receiving element are arranged on the same plane. A similar effect can be obtained by arranging the light-receiving element on the inside and the light-receiving element on the outside, or the light-emitting element on the outside and the light-receiving element on the inside.

In this example, six light emitting elements are used, but
Any number of them may be arranged so as to satisfy equation (1).

Although the present invention performs signal transmission using a light emitting diode and a phototransistor, similar effects can be obtained with any other light emitting element or light receiving element.

In this example, N light-emitting elements are provided at equal angular intervals, and two light-receiving elements are provided at predetermined angular intervals. N light-receiving elements may be provided, in which case the configuration is such that the signals of the N light-receiving elements are logically summed to reproduce a multiplexed signal.

According to the present invention, a mounting structure is adopted in which a plurality of light emitting elements are provided on the rotating side of the steering wheel, a plurality of light receiving elements are provided on the fixed side of the steering wheel, and at least one of them is arranged at equal intervals on the circumference. , it can be easily installed in a small installation space, and therefore the manufacturing cost can be reduced, which is an excellent effect.

Furthermore, the present invention employs a circuit configuration in which all of the plurality of light emitting elements are driven in response to one switch operation, and the OR of the light reception signals from the light reception elements at that time is calculated, so that the switch signal can be accurately detected. It is possible to improve practicality while ensuring reliability.

[Brief explanation of the drawing]

FIG. 1 is a mounting diagram of an embodiment of a transmission device according to the present invention, FIG. 2 is a layout diagram of a light emitting element and a light receiving element in an embodiment of a transmission device of the present invention, and FIG. 3 is a mounting diagram of an embodiment of a transmission device according to the present invention. The electrical circuit diagram of the embodiment, Fig. 4 is a waveform diagram of the transmitted multiplexed signal in the above embodiment, and Fig. 5 shows the set with the minimum deviation angle between the light emitting element and the light receiving element when the steering wheel is rotated once. 6 and 7 are diagrams showing the relationship between deviation angles, FIGS. 6 and 7 are layout diagrams of a light emitting element and a light receiving element in another embodiment of the apparatus of the present invention, and FIG. 8 is a power supply circuit diagram of the apparatus of the present invention. 11A-11F... Light emitting diode, 12A,
12B...Phototransistor, 20...Encoder circuit, 22...Turn right switch, 23...
Turn left switch, 24...Horn switch.

Claims (1)

[Scope of Claims] 1. A plurality of switches provided on a steering wheel of an automobile; an encoding circuit that encodes signals from each switch and outputs a coded signal; a plurality of light emitting elements arranged at predetermined intervals on a circumferential plane so as to rotate together with the steering wheel; and each time the encoded signal is generated from the encoding circuit, the light emitting elements a light-emitting element drive circuit that causes all of the light-emitting elements to emit light and outputs an optical signal corresponding to the encoded signal; a plurality of light-receiving elements fixedly attached to the vehicle body side at predetermined intervals on a circumferential plane drawing concentric circles, and receiving optical signals from the light-emitting element and outputting a light-receiving signal; an OR circuit that logically ORs the received light signals from the elements and outputs the result as an OR signal; a load driving circuit for driving a load, and at least one of the plurality of light emitting elements and the plurality of light receiving elements are arranged at equal intervals on a circumference. Signal transmission equipment. 2. The switch signal transmission device according to claim 1, wherein the light emitting element includes N (N≧2) light emitting diodes arranged at equal intervals, and the light receiving element has a size of 3/2× A switch signal transmission device for an automobile, characterized in that it includes two phototransistors arranged at an interval of 360°/N. 3. The switch signal transmission device according to claim 1, wherein the light receiving element includes N (N≧2) phototransistors arranged at equal intervals, and the light emitting element includes 3/2× A switch signal transmission device for an automobile, comprising two light emitting diodes arranged at an interval of 360°/N.