JPS6176960A - Rotational direction detecting device - Google Patents

Abstract

PURPOSE:To curtail the number of parts by arranging a transmission window of asymmetrical shape in a rotary plate attached axially to a revolving shaft, so that a variation of an optical signal transmitting through the transmission window can be detected by rotation of the revolving shaft. CONSTITUTION:A triangular window 11 of asymmetrical shape is arranged in a rotary plate 1 attached axially to a revolving shaft 2. First of all, when the rotary plate 1 is rotated in the direction L, a triangular waveform of rising rightward is generated in accordance with the shape of the triangular window 11 at a point (a) of the emitter side of a phototransistor 32 by a light shielding action, and this triangular waveform is amplified 5. This waveform rises slowly, and when it is differentiated 6, its peak voltage is a lower voltage than a voltage divided by resistances R12, R13;, and a signal outputted to an output part (b) of the second waveform forming circuit 8 becomes a low voltage signal. On the other hand, when said rotary plate is rotated in the direction R, a triangular waveform generated in the output side of the transistor 32 rises suddenly, and when it is differentiated 6, a large waveform is outputted, its peak voltage becomes a higher voltage then the voltage divided by the resistances R12, R13, a pulse waveform is outputted to the output part (b) of the circuit 8, and a rotational direction of a handle is detected.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a rotation direction detection device capable of detecting the rotation direction of a rotation shaft of a steering wheel or the like of a vehicle.

BACKGROUND OF THE INVENTION Conventionally, this type of rotational direction detection device has been used to detect rotation using a photointerrupter and a slit in a disk attached to the rotating shaft of a motor, as shown in Figure 2g of Japanese Patent Laid-Open No. 58-33571. Detective, I have something to give you.

Also, as another conventional example, Nissan Motor Co., Ltd.
Service Bulletin No. 491 (BL-14) issued in October
As shown in the figure, a rotary plate with a slit is attached to the steering wheel as a steering angular velocity sensor, and the sensor detects the on/off pattern of light passing through the slit to detect the rotation angle of the steering wheel, and based on the phase difference between the two sensors. There was something that could tell whether the steering wheel was turning right or left.

Problems to be Solved by the Present Invention According to the prior art, two (Ii!1 or more) light receiving elements are necessarily required to detect the rotation direction based on the phase difference, and it is necessary to detect the phase difference ( Arranging the two photodetectors with their optical axes accurately aligned requires a certain amount of space, and careful attention must be paid to manufacturing and assembly precision.Furthermore, the lead wires from the photodetector to the amplifier transmit minute signals. to send /-
However, since there are two sensors, at least two /- lead wires are required.

Means for Solving the Problems The present invention was devised to eliminate such drawbacks, and includes a rotary plate having a plurality of asymmetric transmission windows arranged concentrically, and a rotating plate that is pivoted. A rotating shaft, a pair of optical signal transmitting/receiving units that transmit and receive optical signals through the transmission window of the rotating plate, and a pair of optical signal transmitting/receiving units that detect the rotational direction of the rotating shaft based on the differential value of the output signal of the optical signal transmitting/receiving unit. The present invention provides a rotation direction detection device comprising a circuit section.

Made for The present invention has the following effects from the above-mentioned means.

In other words, the optical signals transmitted and received by the optical signal transmitting/receiving section generate different patterns depending on the direction of rotation of the rotary plate because the shapes of the transmission windows arranged on the rotary plate are asymmetrical.

Then, by differentiating this optical signal, the difference between the patterns is emphasized, and the rotation direction of the rotation axis is detected by the detection circuit section.

Example Next, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a diagram showing a rotary plate according to a preferred embodiment of the present invention, and FIG. 2 is a detailed view of the main parts thereof.

In Figures 1 and 2, 1 is a rotary plate, the rotary plate 1 is pivotally attached to a steering wheel/gift 2 as a rotating shaft, and the rotary plate 1 has a plurality of concentric rings. The unpaired 1,000-shaped triangular windows 11 are arranged (・ru.

Further, FIG. 3 is an electric circuit diagram showing a preferred embodiment of the present invention. In FIG. The anode of the phototransistor 32 and the collector of the phototransistor 32 are each connected to the constant voltage section 4, and the emitter of the phototransistor 32 is connected to the input section of the amplifier circuit 5. A rotary plate 1 is interposed and arranged so that an optical signal is turned on and off at a triangular window 11 by rotation of a steering wheel/gift 2.

Next, the output section of the amplifier circuit 5 is connected to a differentiating circuit 6 and a first waveform shaping circuit γ, and the output section of the differentiating circuit 6 is connected to a second waveform shaping circuit γ.
The waveform shaping circuits 8 are connected to the respective waveform shaping circuits 8.

Here, the amplifier circuit 5 is composed of a first comparator circuit Q1 and a resistor R8 or R4, and the differentiator circuit 6 is composed of a first comparator circuit Q1 and a resistor R8.
diode D1, capacitor CI and resistor R,,,R.

The first waveform shaping circuit γ is composed of a second comparator circuit Q.
The second waveform shaping circuit 8 consists of a third comparator circuit Q3 and a resistor R11.
9 is a main switch, and 10 is a power supply.

Next, the operation will be explained using an electrical characteristic diagram of a preferred embodiment of the present invention shown in FIG. 4 (without aJ and FIG. 4(c)).

First, the passenger turned on the main switch 9 ft, (
When the handle is rotated counterclockwise between seconds) and I2 (seconds), the rotary plate 1 rotates in the L direction shown in FIG. Figure 4 (1+ (seconds) of al
A triangular waveform rising to the right as shown in 2 (seconds) is generated. This triangular waveform is amplified by the amplifier circuit 5. Since this waveform has a slow rise, when it is differentiated by the differentiator circuit 6, only a minute waveform is not output. , its peak voltage is lower than the voltage divided by the resistors R, □ and the resistor R13, and the signal output to the output section of the second waveform shaping circuit 8 is as shown in FIG.
It becomes a low voltage signal as shown in bl.

On the other hand, when the handle is turned clockwise when I3 (seconds) (・1< (seconds), the output side of the transistor is
As shown in al, a triangular waveform descending to the right is generated between I3 (seconds) and 1+ (seconds). This waveform has a rise of 1@ and a peak, and when differentiated by the differentiating circuit 6, a large waveform is output, and the peak voltage is higher than the divided voltage at the resistors R, 21R, 3, and the second waveform shaping circuit 8 To output the output part of Fig. 4(b), I3 (seconds) and I4 (seconds).
The pulse waveform shown in between is output.

Accordingly, the rotational direction of the handle is detected by the signal from the output section of the second waveform shaping circuit 8.

Further, the output signal of the amplifier circuit 5 is transmitted to a first waveform shaping circuit 7.
is input into the pulse signal and converted into a pulse signal as shown in Fig. 4 (cJK).And by counting this pulse signal,
・The rotation angle of the handle is detected.

In a preferred embodiment of the present invention, when the handle is rotated counterclockwise, the output section of the second waveform shaping circuit 8 outputs the same low voltage signal as when the handle is not rotated. In order to distinguish between the two, the first waveform shaping circuit 7
It is preferable to detect based on logical conditions with the signal output from the .

Furthermore, the shape of the transparent windows arranged on the rotary plate 1 is not limited to a triangular shape, but may also have a stepped shape or a continuous arrangement of holes 12 of different sizes as shown in FIG. (・. Also, the transparent window may be opaquely printed on a transparent film (・.

Furthermore, the optical signal transmitting/receiving section may use an optical fiber.

Effects of the Present Invention As described above, in the present invention, transmitting windows having an asymmetrical shape such as a triangle are arranged on a rotary plate mounted on a rotary shaft, and optical signals are transmitted and received through the transmitting windows by rotation of the rotary shaft. Since the structure is configured such that the change in the optical signal of the section is differentiated and determined by the detection circuit section, only one pair of optical signal transmitter/receiver section is required, and the space is small.

Further, dimensional accuracy unlike the conventional technology for detecting phase difference is not required, and therefore an optical fiber can be used for the optical signal transmitting/receiving section.

[Brief explanation of drawings]

FIG. 1 is a front view showing a rotating plate according to a preferred embodiment of the present invention. FIG. 2 is a detailed view of the main part of FIG. 1. FIG. 3 is an electrical circuit diagram showing a preferred embodiment of the present invention. FIG. 4 is a custom electrical diagram of each part of FIG. 3. FIG. 5 is a detailed view of a main part of a rotating plate according to another embodiment of the present invention. 1...Rotating plate, 2...Steering ring 7 shaft, 31
...Light emitting diode, 32...Phototransistor, 5
...Amplification circuit, 6.. Differentiation circuit, 7.. First waveform shaping circuit, 8.. Second waveform shaping circuit, 11.. Triangular window 1st vIA 2nd fffi

Claims (1)

[Claims] a rotating plate having a plurality of asymmetric transmission windows arranged concentrically; a rotating shaft to which the rotating plate is mounted; and a pair of optical signal transmitting/receiving units transmitting and receiving optical signals through the transparent windows of the rotating plate. , a detection circuit section that detects the rotation direction of the rotating shaft based on the differential value of the output signal of the optical signal transmitting/receiving section.