JPH07209023A - Encoder and its manufacture device - Google Patents

Abstract

PURPOSE:To provide an encoder which does not deteriorate in measuring accuracy even if its overall size is reduced by reducing the number of component part items so as to reduce the error of assembly. CONSTITUTION:A light beam is applied on a scale part 14 which is formed by arranging reflection parts 16a and non-reflection parts 16b of specified widths alternately in specified directions, and the light signal reflected on or transmitted through the scale part 14 is detected by a light sensor 16 arranged oppositely on the scale part 14. Also, on an encoder to detect a relative movement amount between the scale part 14 and the light sensor 16, the scale part 14 is formed directly on the surface of a moving body 11 of which movement amount is to be measured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an encoder and its manufacturing apparatus.

[0002]

2. Description of the Related Art An encoder is widely known as a device for measuring the displacement of a moving body that makes a rotary motion or a linear motion.

For example, an optical rotary encoder for measuring a rotational displacement has a structure in which the displacement of a rotating body having an optical slit is detected by an optical sensor.
An example thereof is shown in FIG.

In FIG. 4, the scale 1 rotates about an axis 2, and an optical slit 5 is formed on the outer peripheral edge of the scale 1. The scale 1 is adhesively fixed to the shaft 2 by using a ring 3. The optical sensor 4 has an optical slit 5
Is formed of a transmissive optical sensor or a reflective optical sensor, and is arranged at a position close to and facing the rotational trajectory of the optical slit 5 in the axial direction of rotation.

[0005]

However, in the conventional encoder configured as described above, the scale 1, the shaft 2 and the ring 3 are individually manufactured, and the ring 1 is used to accurately move the scale 1 to the shaft 2. It had to be adjusted and fixed.

That is, the optical slit 5 was not directly formed on the surface of the rotating body to be measured. Therefore, the scale 1 in which the optical slit 5 is formed
Using a ring 3 etc. that is separate from
Since it is necessary to position and attach to, there is a problem that it takes time to position.

Further, in order to miniaturize the encoder, it is necessary to reduce the diameter of the scale 1 and the diameter of the shaft 2, but it takes time and effort to adjust and fix the minute parts with high accuracy, and from the outside. There has been a problem that the measurement accuracy as an encoder is deteriorated as a result of the decrease in the positioning accuracy due to the applied vibration.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to solve the above-mentioned problems of the prior art, to reduce the labor for positioning the scale and the shaft, to provide a compact encoder which is resistant to vibrations and a manufacturing apparatus thereof. Is.

[0009]

In order to achieve the above object, an encoder according to the present invention irradiates a scale portion formed by alternately arranging a reflecting portion and a non-reflecting portion having a predetermined width with light, In an encoder that detects an optical signal reflected or transmitted by the scale unit by a sensor arranged facing the scale unit, and detects a relative movement amount between the scale unit and the sensor, the scale unit is a moving unit. It is characterized in that it is formed directly on the surface of the moving body whose quantity is to be measured.

Further, the moving body is a rotating body, and the reflecting portion and the non-reflecting portion of the scale portion are arranged concentrically with respect to the shaft center on an end face perpendicular to the shaft center of the rotor. It is characterized by being.

Further, the scale portion formed by alternately arranging the reflecting portions and the non-reflecting portions having a predetermined width is irradiated with light, and the optical signal reflected or transmitted by the scale portion is opposed to the scale portion. In an encoder manufacturing apparatus that manufactures an encoder that detects a relative rotational movement amount of the scale unit and the sensor, which is detected by a provided sensor, the reflecting unit and the non-reflecting unit of the scale unit are Arranged concentrically with respect to the axis on the end face perpendicular to the axis of the rotary shaft, the encoder manufacturing apparatus,
A calibration reference encoder having a rotation axis coaxially coupled to the rotation axis of the encoder for generating a clock signal for calibration; rotating means for rotating the encoder and the rotation axis of the calibration reference encoder; Means for rotating the rotary shafts of the encoder and the calibration reference encoder by means for comparing the pulse signal from the encoder with the clock signal; and position adjusting means for adjusting the positional relationship between the sensor and the scale unit. ,
It is characterized by including.

[0012]

According to the present invention, since the scale portion is formed directly on the surface of the moving body, it is possible to save the labor for positioning and mounting the scale portion on the moving body.
Further, the number of parts can be reduced, an error due to assembly can be reduced, and the measurement accuracy of the encoder is less likely to deteriorate.

In the present invention, the rotating shafts of the encoder and the calibration reference encoder are rotated by the rotating means, and the pulse signal detected by the sensor of the encoder to be manufactured is compared with the clock signal for calibration from the calibration reference encoder, Based on the comparison result, the positional adjustment means adjusts the positional relationship between the sensor and the scale portion. Since the rotary shaft of the encoder and the rotary shaft of the calibration reference encoder are coaxially coupled to each other, the positional relationship between the sensor and the scale part can be adjusted irrespective of the presence or absence of fluctuations in the rotation speed due to the rotation by the rotating means. it can.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a block diagram showing a first embodiment of an encoder of the present invention. Rotating body 11 as a moving body
Is composed of a cylindrical rotary shaft 12 and a flat plate-shaped disc 13 which is integrally formed with the rotary shaft 12 and spreads at the tip end thereof in a direction perpendicular to the axis. The scale member 14 is directly formed on the surface of the extending plate 13 integrally with the disc 13. On the surface of the scale member 14, there are formed optical slits 15 in which reflecting portions 15a and non-reflecting portions 15b are alternately arranged at a predetermined interval and are concentrically arranged with respect to the axis of the rotating shaft 12. There is. In addition, the optical sensor 16 faces the optical slit 15.
Is provided. Although not specifically shown, the optical sensor 16 includes a light emitting and receiving unit 16a and an optical fiber 16b,
It is connected to a signal control device 17 in which a light source and a signal processor are housed.

The scale member 14 formed integrally with the disk 13 directly on the surface of the disk 13 is manufactured as follows. The scale member 14 is directly formed on the surface of the disk 13 integral with the rotating shaft 12 by using a photoetching process. For this purpose, first, the surface of the disk 13 is polished and a metal material such as aluminum is deposited on the surface by sputtering.

Next, the disk 13 is aligned with the optical system so that the optical axis of the optical system (not shown) in the photoetching process coincides with the axis of the rotary shaft 12. This optical system contains the original plate of the optical slit,
This original plate is previously positioned with high accuracy with respect to the optical axis of the optical system.

Next, a photo-etching agent is applied on the surface of the metal material in advance, and exposure is performed using the above-mentioned optical system. As a result, the reflective portion 15a and the non-reflective portion 15b are formed on the metal material surface.

Since the optical system is preliminarily aligned with the axis of the rotary shaft 12 with high accuracy, the optical slit 15 should be formed in a state of being accurately positioned with respect to the axis of the rotary shaft 12. You can

Further, since the optical slit 15 is directly formed on the surface of the disk 13 through the metallic material deposited by sputtering, in the prior art, the scale 1 is set on the axis 2 by using the ring 3 or the like. Unlike the case of positioning and mounting, there is no need to use the ring 3 etc.
Further, the alignment between the scale 1 and the shaft 2 may not be required for each rotary encoder manufactured.

The optical slit 15 may have any shape as long as the reflected light alternately changes in intensity, and its shape may be uneven.

The step of forming the optical slit 15 is not limited to the photoetching process, and other means capable of fine processing may be used. For example, direct cutting by ion beam processing may be used. Also,
Instead of the photo-etching process, it is also possible to draw an optical slit by using an electron beam or the like on the surface of a metal material formed by deposition by sputtering or the like.

What should be noted here is that the formation of the optical slit 15 is directly performed integrally with the rotating body 11. That is, in the step of forming the optical slit 15 such as the photo etching process, the lens optical axis of the transfer device for forming the optical slit 15 is set to the rotation axis 1.
Positioning is performed with high accuracy with respect to the axis of the second shaft, and the optical slits 15 are formed in this positioned state, so that the individual reflecting portions 15a and non-reflecting portions 15b to be manufactured are rotated about the rotation axis of the rotating body 11. It can be easily formed into a concentric circle with high precision.

In the encoder thus constructed, light is emitted from the light emitting / receiving section 16a of the optical sensor 16 to the optical slit 15. When the rotating shaft 12 rotates, the optical signal reflected by the reflecting portion 15a of the optical slit 15 changes periodically. The optical signal reflected by the reflector 15a is detected by the light emitter / receiver 16a, processed by the signal controller 17 via the optical fiber 16b, and an output signal corresponding to the rotation amount is obtained.

According to the configuration of this embodiment, the optical slit 15 is directly formed on the surface of the rotating body 11 integrally with the rotating body 11. Therefore, the optical slit 15 of the scale member 14 is positioned on the rotating body 11. It is possible to save the trouble of attaching it. Further, the number of parts can be reduced, an error due to assembly can be reduced, and deterioration of the measurement accuracy of the encoder hardly occurs.

Next, a second embodiment of the encoder according to the present invention will be described with reference to FIG. The same components as those in the first embodiment are designated by the same reference numerals, and the duplicated description will be omitted.

In FIG. 2, the disc 1 is on the surface of the disc 13.
A disc-shaped light-transmissive member 20 made of a light-transmissive material is mounted integrally with the member 3. The light transmissive member 20 is made of, for example, quartz glass. The light transmissive member 20 is formed by directly depositing quartz glass on the surface of the disk 13 by sputtering or the like. The scale member 14 is a light transmissive member 20.
It is formed integrally with. As in the case of the first embodiment, the scale member 14 is formed by depositing a metal material such as aluminum by sputtering or the like, and thereafter, the reflective portion 15a and the non-reflective portion 15b are formed on the surface of the metal material by a photoetching process. Then, the optical slit 15 is formed integrally with the light transmissive member 20. By this, disk 1
The scale member 14 is directly formed on the surface of No. 3.

In addition to the above embodiment, a flat encoder as a whole can be manufactured by forming an optical slit 15 at the outer peripheral end of the scale member 14.

An embodiment of the encoder manufacturing apparatus according to the present invention will be described with reference to FIG. The encoder manufacturing apparatus includes a calibration reference encoder 32 for calibrating a manufactured encoder 31, which is a manufacturing target.

The scale member 44 of the encoder 31 to be manufactured
The reflective portion and the non-reflective portion are arranged concentrically with respect to the axial center of the rotary shaft 33 of the encoder 31 to be manufactured, on the end face perpendicular to the axial center.

The calibration reference encoder 32 has a rotary shaft 34 protruding to both sides of the main body, and the rotary shaft 34 protruding to one side.
Are coaxially coupled to the rotary shaft 33 of the encoder 31 to be manufactured via a coupler 37. The rotary shaft 34 protruding to the other side is coaxially coupled to the rotary shaft 35 of the drive motor 36 via a coupler 37. Manufacturing encoder 3
1, the calibration reference encoder 32, and the drive motor 36 are supported by support members 39, 40, and 41 installed on a base 38, respectively.

The light emitting / receiving unit 43a of the optical sensor 43 of the encoder 31 to be manufactured is attached to the position / orientation adjusting means 42 installed on the base 38. Position / orientation adjusting means 42
Includes a position moving means in each axial direction of the x, y, and z axes, and a tilt mechanism. By the position and orientation adjusting means 42,
The attitude of the light emitting / receiving unit 43a is adjusted so that the light emitting / receiving surface of the light emitting / receiving unit 43a is parallel to the surface of the scale member 44. Further, the position of the light emitting / receiving unit 43a is adjusted so that the light emitting / receiving unit 43a is positioned so as to face the reflection portion and the non-reflection portion of the scale member 44. In this way, the position / orientation adjusting means 42 can adjust the position and orientation of the light emitting / receiving unit 43a with respect to the scale member 44 of the encoder 31 to be manufactured. The position / orientation adjusting means 42 is the signal accuracy measuring device 4
8 is driven via a position / orientation adjustment drive unit 46 connected to the control unit 8.

The light emitting / receiving section 43a of the optical sensor 43 is connected to the signal control device 45 via the optical fiber 43b, and a pulse signal corresponding to the rotation amount is obtained from the signal control device 45. This pulse signal is a signal accuracy measuring device. Sent to 48. The signal accuracy measuring device 48 is also fed with the clock signal of the calibration reference encoder 32.

An observation device 47, which is a microscope, is provided above the encoder 31 to be manufactured in order to observe the relative position between the light emitting / receiving unit 43a and the scale member 44.

Next, the operation of this embodiment will be described. When the rotary shaft 35 of the drive motor 36 rotates, the rotary shaft 34 and the rotary shaft 33 rotate. The calibration reference encoder 32 outputs a reference clock signal according to the rotation amount, and at the same time, the manufactured encoder 31 outputs a pulse signal. In the signal accuracy measuring device 48, the clock signal and the pulse signal are subjected to comparative measurement of the period of the reference clock signal from the reference encoder 32 and the pulse signal of the encoder 31 to be manufactured. Based on the result of this comparison, the position / orientation adjustment driving unit 46 receives an instruction from the signal accuracy measuring device 48, and the position / orientation adjusting unit 42 causes the light emitting / receiving unit 43a to / from the scale member 44 so that their cycles and the like match.
Adjust the position and posture of the.

According to the structure of this embodiment, the rotary shaft 33 of the encoder 31 to be manufactured and the rotary shaft 34 of the calibration reference encoder 32 are coaxially coupled to each other.
Even if the rotation speed changes due to the rotation by 6, the positional relationship between the light emitting / receiving unit 43a of the optical sensor 43 and the scale member 44 can be adjusted with high accuracy without being affected by the rotation speed fluctuation.

That is, since the pulse signal of the reference encoder 32 rotating together with the manufactured encoder 31 is used to measure the accuracy of the pulse signal of the manufactured encoder 31, the rotation speed of the manufactured encoder 31 changes. However, the measurement accuracy is always constant, and the measurement accuracy does not change depending on the rotation speed. Further, even if the manufactured encoder 31 changes in rotation, it rotates together with the reference encoder 32, and therefore the measurement accuracy does not change due to the change in rotation.

In the above description, the optical rotary encoder has been described as an example, but the present invention is not limited to this and can be applied to an optical linear encoder.

Further, in the above description, the moving body to be measured is the main body of the encoder itself, but the present invention is not limited to the main body itself of the rotary encoder or the linear encoder as the moving body, and a conventional encoder is installed. Any moving body whose movement amount is measured and which can be provided with a scale portion may be used.

[0039]

As described above, according to the configuration of the present invention, since the scale portion is directly formed on the surface of the moving body, the labor for positioning and mounting the scale portion on the moving body is omitted. Further, the number of parts can be reduced, an error due to assembly can be reduced, and deterioration of measurement accuracy of the encoder can be suppressed.

Also, the rotating shafts of the encoder and the calibration reference encoder are rotated by the rotating means, and the pulse signal detected by the sensor of the encoder to be manufactured is compared with the clock signal for calibration from the calibration reference encoder. Based on this, the positional relationship between the sensor and the scale portion is adjusted by the position adjusting means. Since the rotary shaft of the encoder and the rotary shaft of the calibration reference encoder are coaxially coupled to each other, the positional relationship between the sensor and the scale part can be adjusted irrespective of the presence or absence of fluctuations in the rotation speed due to the rotation by the rotating means. it can.

[Brief description of drawings]

FIG. 1 is a perspective view showing a first embodiment of an encoder according to the present invention.

FIG. 2 is a perspective view showing a second embodiment of the encoder according to the present invention.

FIG. 3 is a schematic configuration diagram showing an embodiment of an encoder manufacturing apparatus according to the present invention.

FIG. 4 is a perspective view showing a conventional encoder.

[Explanation of symbols]

 11 Encoder 12 Rotating Shaft 13 Disc 14 Scale Member 15 Optical Slit 15a Reflector 15b Non-Reflector 16 Optical Sensor 16a Emitter / Receiver 17 Signal Controller 20 Light Transmitting Member 26 Light Transmitting Member 31 Manufacturing Encoder 32 Calibration Standard Encoder 33, 34, 35 Rotating shaft 36 Drive motor 37 Coupler 42 Position / orientation adjusting means 45 Signal controller 47 Observation device 48 Signal accuracy measuring device

Claims (3)

[Claims] 1. A scale portion formed by alternately arranging reflective portions and non-reflective portions having a predetermined width is irradiated with light, and an optical signal reflected or transmitted by the scale portion is opposed to the scale portion. In an encoder that detects the relative movement amount between the scale unit and the sensor, which is detected by a provided sensor, the scale unit is formed directly on the surface of the moving body whose movement amount is to be measured. Characteristic encoder. 2. The moving body is a rotating body, and the reflecting portion and the non-reflecting portion of the scale portion are arranged concentrically with respect to the axis of the rotating body on an end face perpendicular to the axis of the rotating body. The encoder according to claim 1, wherein the encoder is provided. 3. A scale portion formed by alternately arranging reflective portions and non-reflective portions having a predetermined width is irradiated with light, and an optical signal reflected or transmitted by the scale portion is opposed to the scale portion. In an encoder manufacturing apparatus that manufactures an encoder that detects a relative rotational movement amount of the scale unit and the sensor, which is detected by a provided sensor, the reflecting unit and the non-reflecting unit of the scale unit are Arranged concentrically with respect to the axis on the end face perpendicular to the axis of the rotation axis, the encoder manufacturing apparatus has a rotation axis coaxially coupled to the rotation axis of the encoder for calibration Calibration reference encoder for generating a clock signal of the encoder, rotating means for rotating the rotary shafts of the encoder and the calibration reference encoder, and the encoder and the encoder by the rotating means. A signal comparing means for rotating a rotation axis of the calibration reference encoder and comparing a pulse signal from the encoder with the clock signal; and a position adjusting means for adjusting a positional relationship between the sensor and the scale portion. Characteristic encoder manufacturing equipment.