JPH04110614A - Encoder - Google Patents

Abstract

PURPOSE:To improve reliability to a large extent and to achieve cost reduction by inputting a pair of detected rotation signals whose phases are different by 90 deg. to each other into exclusive OR circuits. CONSTITUTION:A rotary disk 2 is rotated in the direction of an arrow A together with a rotary shaft 1. The light emitted from each light emitting body 4 passes a rotation detecting pattern and reaches light receiving parts 5a, 5b, 5c and 5d after sequentially passing through slits 7a - 7d. Detected rotation signals (a) - (d) are inputted into a pair of exclusive OR circuits. The sets of the detected rotation signals (a) and (c) and (b) and (d) whose phases are different by 90 deg. to each other among the detected rotation signals (a) - (d) are inputted into the exclusive OR circuits and the signals are processed. Thus, a one- time-count detected rotation signal 11 based on the detected rotation signal (a) and (c) and a double-count detected rotation 12 based on the detected rotation signals (b) and (d) are obtained. Thus, the multiplied-count detected rotation signals 11 and 12 having the double frequencies can be obtained only by electric logical processing.

Description

DETAILED DESCRIPTION OF THE INVENTION a. Industrial Application Field The present invention relates to an encoder, and more particularly, to converting a rotation detection signal obtained from a rotation detection pattern into a double count rotation detection signal having twice the frequency by logic circuit processing. Concerning new improvements to.

b. Prior Art There are various types of optical encoders of this kind that have been used in the past, but a representative one is, for example, the one disclosed in Japanese Utility Model Application Publication No. 1-173625. , rotation detection was performed using a rotation detection signal obtained from a rotation detection pattern of a rotating disk.

C1 Problems to be Solved by the Invention Since the conventional encoder is configured as described above, the following problems existed.

In other words, in the conventional configuration described above, in order to increase the frequency of the rotation detection signal, the rotation detection pattern of the rotating disk must be made denser, and the pattern of the grating that guides the light on the light receiving section side must be made denser. As a result, the process became extremely complicated, resulting in a significant increase in manufacturing costs and a decrease in yield.

The present invention has been made to solve the above-mentioned problems, and in particular, it processes a rotation detection signal obtained from a rotation detection pattern into a double-count rotation detection signal having twice the frequency by processing the rotation detection signal using a logic circuit. The purpose is to provide an encoder with

61 Means for Solving the Problems An encoder according to the present invention detects a rotation detection pattern of a rotating disk disk by a rotation detecting section consisting of a light emitter and a light receiver, and detects rotation of a rotation axis of the rotating disk disk. In the encoder, the rotation detecting section includes first and second detecting sections provided independently from each other to constitute the rotation detecting section, and a first light receiving body provided in the first detecting section and having a pair of light receiving sections. , for inputting a second photoreceptor provided in the second detection section and having a pair of light receivers, each pair of rotation detection signals obtained from the photoreceptor and having a phase difference of 90 degrees from each other, and each of the rotation detection signals; This configuration includes an exclusive OR circuit.

01 action In the encoder according to the present invention, the phase is 90 degrees with respect to each other.
° Since a different pair of rotation detection signals are input to the exclusive OR circuit, the output from the exclusive OR circuit can obtain a double count rotation detection signal having twice the frequency of the rotation detection signal. without any processing on the rotation detection pattern or grating.
The frequency can be easily doubled.

f. Embodiments Hereinafter, preferred embodiments of the encoder according to the present invention will be described in detail with reference to the drawings.

Figures 1 to 4 are for showing the encoder according to the present invention. Figure 1 is a configuration diagram showing the detection state, Figure 2 is a waveform diagram, and Figure 3 shows the logic of the exclusive OR circuit. FIG. 4 is a configuration diagram showing a light receiving state.

In the figure, the reference numeral 1 denotes a rotating shaft that is rotatably held by a bearing (not shown) and has a rotating disk disk 2. A transparent rotation detection pattern 3 is formed on the rotating disk disk 2. A first and second detection section 30.31 has a light emitting body 4 such as an LED above the rotating disc 2, and has a first photoreceptor 20 and a second photoreceptor 21 below it. A rotation detection section 6 consisting of the following is provided.

Each of the detection sections 30, 31 has a substantially U-shaped overall shape and is spaced apart from each other. The first fixed slit plate 7 provided at 30
Each slit 7a.

7b, the light passes through the
A pair of rotation detection signals a with 0° different phases.

It is configured so that C can be obtained.

Further, from the pair of light receiving sections 5C5d of the second photoreceptor 21, the second detecting section 31 forms a grating.
Each slit 7c of the second fixed slit plate 7A provided in
, 7d, a pair of rotation detection signals b and d having a phase difference of 90 degrees shown in FIG. 2 are obtained.

Each photoreceptor 20.21 of each detection unit 30.31 has a first
As shown in the figure, it is configured to detect a rotation detection pattern 3 of one rotating disk disc 2, and each of the rotation detection signals a to d is arranged at an electrical angle of 45 degrees with respect to each other as shown in FIG.
The light receiving sections 5a to 5d constitute a 45° phase difference signal detector.

The encoder according to the present invention is configured as described above, and its operation will be explained below.

First, the rotating disk disc 2 rotates in the direction of the arrow A together with the rotating shaft 1, and the light emitted from each light emitter 4 passes through the rotation detection pattern 3 and sequentially passes through each of the slits 7a to 7d.
The light enters each light receiving section 5a, 5b, 5c5d.

The four rotation detection signals a, b, c, and d obtained from each of the light receiving sections 5a to 5d are rectangular waves whose phases are shifted by 45 degrees from each other, as shown in FIG. The rotation detection signals a to d are input to a pair of well-known exclusive OR circuits 10 shown in FIG.

By inputting the rotation detection signals a, c, b, and d, which are different in phase by 90 degrees from each other among the rotation detection signals a to d, to this exclusive OR circuit 10, the logical configuration shown in FIG. Processed according to the diagram, rotation detection signal a,
A first double count rotation detection signal 1 based on rotation detection signals b and d and a second double count rotation detection signal 12 based on rotation detection signals b and d are obtained.

Each of these double count rotation detection signals 11 and 12 has a frequency that is twice the frequency of the rotation detection signals a to d, and the double count rotation detection signal 11 with double frequency can be obtained by only electrical logic processing. .12 can be obtained.

g1 Effects of the Invention Since the encoder according to the invention is configured as described above, the following effects can be obtained.

In other words, it is possible to obtain a double-count rotation detection signal with twice the frequency by logical processing of four rotation detection signals that differ from each other by 45 degrees in electrical angle, which requires complicated and advanced processing technology unlike the conventional method. It is possible to extremely easily obtain a double-count rotation detection signal with a double wave number without creating a rotating disk having a rotation detection pattern, and it is possible to significantly improve reliability and reduce costs. can.

[Brief explanation of drawings]

1 to 41 are for showing the encoder according to the present invention. FIG. 1 is a configuration diagram showing a detection state, FIG. 2 is a waveform diagram, and FIG. 3 is a logic diagram of an exclusive OR circuit. FIG. 4 is a configuration diagram showing a light receiving state. 1 is a rotating shaft, 2 is a rotating disk disc, 3 is a fixed rotation detection pattern, 4 is a light emitter, 5 is a photoreceptor, 6 is a rotation detection unit, a~
d is a rotation detection signal, 5a to 5d are light receiving units (45° phase difference 4-signal detectors), 10 is an exclusive OR circuit, 1
1.12 is a double count rotation detection signal, 20 is a first photoreceptor, 21 is a second photoreceptor, 30 is a first detection section, and 31 is a second detection section. Kin 1 Figure 2 Figure 3 Figure patent applicant Tamagawa Seiki Co., Ltd. Figure 4

Claims (1)

[Claims] The rotation detection pattern (3) of the rotating disk disk (2) is detected by a rotation detecting section (6) consisting of a light emitter and a photoreceptor, and the rotation detection pattern (3) of the rotating disk disk (2) is In an encoder configured to detect rotation of a rotating shaft (1), first and second detecting sections (30, 31) provided independently of each other to constitute the rotation detecting section (6); 1
A pair of light receiving parts (5a, 5b) provided in the detection part (30)
a first photoreceptor (20) having a
) and has a pair of light receiving parts (5c, 5d).
A photoreceptor (21) and each pair of rotation detection signals (a
, c, b, d) and an exclusive OR circuit (10) for inputting each of the rotation detection signals (a to d). The first photoreceptor (20) and the second photoreceptor (21) are connected to one of the rotating disks while obtaining double-count rotation detection signals (11, 12) with twice the frequency of the detection signals (a to d). An encoder characterized by being compatible with a disk (2).