JPH08205479A - Securing method for rotary disc in rotary encoder - Google Patents

Abstract

PURPOSE: To shorten the axial length of a rotary encoder for detecting the rotary angle of a motor or the like. CONSTITUTION: A rotary disc 2 is fitted, at the central hole 2a thereof, over a first hollow cylindrical core metal 13 having a flange part 13a at one end thereof. A stop ring 14 provided with a plurality of tongues 14a, having inner end part on a circle slightly smaller than the outside diameter of the first tubular core metal 13, is press fitted over the first core metal 13. Consequently, the rotary disc 2 is secured temporarily between the flange part 13a and the first core metal 13. The first core metal is then press fitted with a second hollow tubular core metal 15 having inside diameter nearly equal to the outer diameter of the first tubular core metal 13. The center of a circle arranged with the slit of the rotary disc 2 is matched, as required, with the center of rotation of the second core metal. Subsequently, the rotary disc 2 is bonded, through adhesive or the like, to the first core metal, and a rotary shaft 7 is passed through the central hole 15a of the second core metal 15 before being secured using a stop screw 16 or the like.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary encoder which is mounted on a rotary machine such as a servomotor and generates an electric signal for controlling the position and speed of an output shaft of the rotary machine.
More specifically, it relates to a method of fixing the rotating disk.

FIG. 1 is an example of a rotary encoder. In this example, the light from the light source 1 is applied to the rotating disk 2, the rotating disk 2 is provided with slits 2a and 2b on the circumference, and the light passing through the slits 2a and 2b is fixed at a predetermined position. Light receivers 4a, 4 passing through the slits 3a, 3b
When light is received by b, pulse signals 5a and 5b corresponding to rotation are obtained as two-phase digital signals.

FIG. 2 is a front view of another example of the rotary disk.

[0004]

2. Description of the Related Art FIG. 3 is an exploded view of a conventional rotary disk of a rotary encoder mounted on a rotary shaft of a motor.

FIG. 4 is a cross-sectional view when a rotary disk is attached to a rotary shaft of a motor according to the conventional technique of FIG.

A rotating disk is fixed to a rotating shaft 7 of the motor projecting from a chassis 6 on the back side of the motor. The installation procedure is as follows. The rotary disk 2 is fitted into the small-diameter portion 8a of the hollow cored bar 8 having two different diameters. Then, a retaining ring 9 is press-fitted on the outer side thereof to fix the rotary disc 2 between the portion 8 b having a large diameter of the cored bar 8 and the retaining ring 9. Then, the rotary shaft 7 of the motor is passed through the center hole 8c of the core metal 8, and if necessary, the rotary shaft of the rotary disk 2 and the rotary shaft of the core metal 8 are aligned, and the core screw 8 is used for core alignment. The gold 8 is fixed to the rotating shaft 7 of the motor.

[0007]

In recent years, miniaturization of devices has become an issue in various fields, but the same applies to rotary machines. In particular, since rotary encoders are often mounted in series on the side opposite to the output shaft of the rotary machine, the rotary machine with the encoder becomes longer in the axial direction. Therefore, it is an important issue to reduce the size of the rotary encoder especially in the axial direction.

However, the conventional rotary disk fixing method as shown in FIGS. 3 and 4 has the following problems. Since the press-fitting width of the snap ring is at least 2 mm in order to obtain the fixed strength, the length of the small diameter part of the cored bar 8 is the sum of the press-fitting width of the snap ring and the thickness of the rotating disc (2 mm + disc Thickness) is required. Therefore,
With the core metal 8, the rotating disk 2 and the retaining ring 9 fixed,
The core metal 8 protrudes by 2 mm or more from the side where the retaining ring of the rotating disk is mounted. Therefore, the protruding portion of the cored bar 8 approaches the circuit board 11 facing the rotating disk, and the electronic component cannot be mounted on that portion.

Further, as shown in FIG. 4, the light receiving portion 12 needs to be brought close to the rotating disk 2, but the retaining ring 9 interferes with the light receiving portion 12 and cannot be brought sufficiently close to the rotating disk 2. Further, in order to avoid the retaining ring 9, the light receiving portion 12 must be arranged away from the axis, and the rotating disk diameter must be increased accordingly.

The present invention relates to a method of fixing a rotary disk of a rotary encoder to a rotary shaft, and a fixing method capable of shortening the axial length both near the center of the rotary disk and in the peripheral area. The challenge is to propose.

[0011]

The above-mentioned problem is solved by fitting the center hole of the rotating disk into the hollow cylindrical first cored bar having a flange-shaped portion at one end, and then determining the outer diameter of the cylinder of the first cored bar. The rotating disc is fixed between the collar-shaped portion and the retaining ring by press-fitting a retaining ring having a plurality of tongues having inner ends on a slightly smaller circumference into the first core metal, and This has been solved by a method for fixing a rotary disk of a rotary encoder, characterized in that the core metal 1 is fixed to a rotary shaft.

In a preferred embodiment of the present invention, a hollow core having an inner diameter substantially equal to an outer diameter of a cylinder of the first core metal is provided on a first core metal having a rotary disk fixed between a collar portion and a retaining ring. The cylindrical second cored bar is press-fitted, and the second cored bar is fixed to the rotary shaft by using a potato screw or the like.

[0013]

The rotating disk is supported from the outside only by the collar portion. Therefore, by thinning the collar portion, the length required for fixing the rotating disk can be shortened.

Since the retaining ring is arranged inside the rotating disk, it does not interfere with the arrangement of electronic parts such as the light receiving portion.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 5 is an exploded perspective view for explaining the implementation of the method for fixing a rotary disk according to the present invention.

The center hole 2a of the rotary disk 2 is fitted into the hollow cylindrical first cored bar 13 having a collar-shaped portion 13a at one end. The thickness of the collar portion 13a is 1 mm in consideration of strength.
Around the front is appropriate. The diameter of the center hole 2a is slightly larger than the diameter of the cylinder of the cored bar 13. Then the first core metal 1
The retaining ring 14 having a plurality of tongue pieces 14a having inner ends on the circumference slightly smaller than the outer diameter of the cylinder of No. 3 has the first core metal 1
Press into 3. As a result, the rotary disc 2 has the collar-shaped portion 1
It is fixed between 3a and the first core metal 13. The first core metal 13 is fixed to the rotary shaft 7 by using a screw or the like.

FIG. 6 is an exploded perspective view for explaining a preferred embodiment of the method for fixing a rotating disk according to the present invention.

The center hole 2a of the rotary disk 2 is fitted into the hollow cylindrical first cored bar 13 having a collar-shaped portion 13a at one end. The thickness of the collar portion 13a is 1 mm in consideration of strength.
Around the front is appropriate. The diameter of the central hole 2a is the first
It is slightly larger than the diameter of the cylinder of the core metal 13. Next, the retaining ring 14 having a plurality of tongue pieces 14a having inner ends on the circumference slightly smaller than the outer diameter of the cylinder of the first core 13 is press-fitted into the first core 13. As a result, the rotary disk 2 is temporarily fixed between the collar-shaped portion 13a and the first core metal 13.

A hollow cylindrical second core metal 1 having an inner diameter substantially equal to the outer diameter of the cylinder of the first core metal 1 is added to the first core metal 1.
Press in 5. If necessary, the second mandrel 15 is temporarily fixed to a temporary rotating shaft, and the second rotating shaft 15 is temporarily fixed so that the center of rotation of the temporary rotating shaft coincides with the center of the circle in which the slit of the rotating disk is arranged. The position of the rotary disk with respect to the first core metal is adjusted to align the cores, and the rotary disk is fixed to the first core metal with an adhesive or the like.

Next, the temporary rotary shaft is removed, the rotary shaft 7 is inserted through the center hole 15a of the second core metal 15, and the potato screw 1
Both are fixed to each other using 6 or the like.

FIG. 7 is a sectional view when the rotary disk 2 is attached to the rotary shaft 7 by the method shown in FIG.

The rotating disk 2 is attached to the rotating shaft 7 of the motor protruding from the rear chassis 6 of the motor by the method shown in FIG.

The rear chassis 6 of the motor and the rotating disk 2
A light source 1 such as a laser diode or an LED is arranged between them, and the housing 1a of the light source 1 is fixed to the back chassis 6 of the motor by an appropriate method.

The rotary disk 2 has slits 2a and 2b as shown in FIGS. 1 and 2, and the light passing through the slits 2a and 2b is received by the light receiving portion 17. The light receiving unit 17 includes the fixed slits 3a and 3b and the light receivers 4a and 4b shown in FIG.

As can be seen from FIG. 7, only the thickness of the collar-shaped portion 13a of the first cored bar 13 is required on the outer side of the rotary disk 2, so that the thickness of the collar-shaped portion reduces the thickness of the light receiving portion 1.
7 can be brought closer to the rotating disc 2.

The circuit board 19 on which the light receiving portion 17 and the electronic circuit portion 18 are mounted is fixed to the chassis of the motor or other members as required.

[0027]

Since the retaining ring does not become an obstacle, the light receiving portion can be arranged sufficiently close to the rotating disk and can also be arranged close to the shaft. Therefore, the diameter of the rotating disk can be reduced. Therefore, since the distance between the slits 2a and 2b and the fixed slits 3a and 3b can be reduced, the noise caused by the optical system can be reduced, and the electronic circuit 18 attached to the light receiving unit 17 can be brought close to the rotary disk 2. You can In addition, the electronic component can be mounted on the entire surface of the circuit board without the protruding portion of the core bar hindering the component mounting on the circuit board. From the above, according to the present invention, not only the rotary encoder can be downsized in the axial direction, but also the radial encoder can be downsized.

[Brief description of drawings]

FIG. 1 is a perspective view of an example of a rotary encoder.

FIG. 2 is a front view of another example of a rotating disk.

FIG. 3 is an exploded view of a rotary disk of a rotary encoder mounted on a rotary shaft of a motor according to a conventional technique.

FIG. 4 is a cross-sectional view when a rotary disk is attached to a rotary shaft of a motor according to the conventional technique of FIG.

FIG. 5 is an exploded perspective view for explaining the implementation of the method for fixing a rotating disc of the present invention.

FIG. 6 is an exploded perspective view for explaining the best mode for carrying out the method for fixing a rotating disk according to the present invention.

FIG. 7 is a cross-sectional view when the rotary disk is attached to the rotary shaft by the method of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 light source 2 rotating discs 3a, 3b fixed slits 4a, 4b light receiver 6 motor back chassis 7 rotating shaft 8 core metal 9 snap ring 10 potato screw 11 circuit board 12 light receiving part 13 first core metal 13a collar portion 14 stopper Wheel 14a Tongue piece 15 Second core metal 16 Imo screw 17 Light receiving part 18 Electronic circuit part 19 Circuit board

Claims (3)

[Claims] 1. A hollow cylindrical first cored bar having a collar-shaped portion at one end thereof is fitted with a center hole of a rotary disk, and then an inner end is formed on a circumference slightly smaller than the outer diameter of the cylinder of the first cored bar. A retaining ring having a plurality of tongues each having a portion is press-fitted into the first core metal to fix the rotating disk between the collar-shaped portion and the retaining ring, and the first core metal is attached to the rotating shaft. A method for fixing a rotary disk of a rotary encoder, characterized by fixing. 2. A hollow cylinder having an inner diameter substantially equal to the outer diameter of the cylinder of the first cored bar on a first cored bar in which a rotary disk is fixed between the collar-shaped portion and the retaining ring by the method of claim 1. A method for fixing a rotary disk of a rotary encoder, comprising press-fitting a second core metal in the form of a ring, and then fixing the second core metal to a rotary shaft. 3. A hollow cylinder having a first core having a rotary disk fixed between the collar-shaped portion and a retaining ring according to the method of claim 1 and having an inner diameter substantially equal to the outer diameter of the cylinder of the first core. -Shaped second cored bar is press-fitted, this second cored bar is temporarily fixed to a temporary rotation shaft, and the first center is arranged so that the rotation center of the temporary rotation shaft coincides with the rotation center of the slit of the rotary disk. Adjusting the position of the rotary disc with respect to the core metal, fixing the rotary disc to the first core metal with an adhesive or the like, and then removing the temporary rotary shaft and fixing it to the target rotary shaft. How to fix the rotating disk of the rotary encoder.