JPH0442754A - How to install the motor encoder - Google Patents

Abstract

PURPOSE:To reduce manpower required for mounting an encoded disc, e.g. a slit disc, on a motor shaft by sandwiching the encoded disc between the outer circumference of a retainer ring and the receiving face of a receiving member and then press fitting and positioning three members simultaneously on the motor shaft. CONSTITUTION:An encoded disc 32 is provided with a central hole to be press fitted with a motor shaft 17. The encoded disc 32 is sandwiched between the outer circumference of a retaining ring 40 comprising resilient part 40A inclining in the axial anti-slip direction having tip part to be press fitted over the motor shaft 17 and the receiving face 39A of a receiving member 39 having the receiving face 39A perpendicular to the motor shaft 17 to be press fitted over the motor shaft 17, and then these three members are press fitted and positioned on the motor shaft 17 simultaneously. Consequently, manpower required for fixing the encoded disc 32 such as a slit disc to the motor shaft 17 can be reduced resulting in simplification of structure and cost reduction.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an encoder mounting method for positioning and fixing an encoder encoding disc, such as a slit disc, on a motor shaft.

[Conventional technology]

In motors such as stepping motors, an encoder is installed to detect the rotation angle of the motor, and feedback control of the motor drive is performed based on the detection information from the encoder. This prevents rotational accuracy from decreasing due to step-out, especially during high-speed rotation. Efforts are being made to prevent such things.

In this encoder-equipped motor, a sensor such as a photointerrupter is positioned and fixed on the stationary side of a motor case, and a coding disk such as a slit disk is positioned and fixed on the motor shaft.

By the way, in conventional encoder-equipped motors, when attaching a coding disk such as a slit disk to the motor shaft, first attach a receiving member having a receiving surface for positioning the coding disk and a center boss to the motor shaft. The method of attachment was to press fit the coded disc into the receiving member, and then fasten the screws to the receiving member with screws or the like to fix the coded disc.

[Technical Problems to be Solved by the Invention] However, with this conventional encoder mounting method, there is a problem that it takes a lot of man-hours to attach a coding disk such as a slit disk, which makes the work complicated and increases the cost. there were.

The present invention has been made in view of these technical problems, and can significantly reduce the number of man-hours required to attach a coded disk such as a slit disk to a motor shaft, simplifying the structure and The object of the present invention is to provide a method for attaching an encoder to a motor that can reduce costs.

[Means for Solving the Problems] A method for attaching an encoder to a motor according to the present invention includes forming a center hole in a coding disk into which a motor shaft is press-fitted;
a retainer ring having a spring part that is inclined in the axial direction to prevent it from coming off and whose tip is press-fitted into the motor shaft, and a flat outer peripheral part;
A receiving member having a receiving surface perpendicular to the motor shaft and press-fitted to the motor shaft is used, and the coded disc is sandwiched between the outer periphery of the holding ring and the receiving surface of the receiving member. By configuring these three members to be press-fitted and positioned simultaneously on the motor shaft, the number of man-hours required to attach a coding disk such as a slit disk to the motor shaft can be significantly reduced, simplifying the structure and The present invention provides a method for attaching an encoder to a motor that can reduce costs.

〔Example〕

Hereinafter, the present invention will be specifically explained with reference to the drawings.

FIG. 1 is a longitudinal sectional view showing the structure of a stepping motor in which the encoder mounting method according to the present invention is implemented.

In FIG. 1, a bearing housing 11 is formed in the center of a drum-shaped motor case 10 with one end open, and a mounting plate 12 is formed on the open end surface of the motor case 10.
is fixed by fixing means such as caulking 13, and another bearing housing 14 is formed at the motor shaft center of the mounting platework 2.

The attachment root 12 also serves as an end plate that seals the open end surface of the motor case 10.

Bearing 1 press-fitted into each bearing housing 11.14
5.16, the motor shaft 17 is pivotally supported.

A rotor 18 is press-fitted and fixed to the motor shaft 17 in the motor case 10, and rotor magnets 19 magnetized to N and S poles are formed at a predetermined pitch in the circumferential direction on the outer periphery of the rotor 18. There is.

A yoke having pole teeth facing the rotor magnet 19 is disposed inside the motor formed by the motor case 10 and the mounting plate 12.
A stack of excitation coils 20, 21 is arranged.

The yokes include a first outer yoke 22 fixed to the end surface of the motor case 10, a first inner yoke 23 and a second inner yoke 24 joined back to back, and a second inner yoke fixed to the inner surface of the mounting plate 12. It consists of an outer yoke 25.

A first excitation coil 20 is installed inside the first inner and outer yokes 22.23 via a bobbin 26, and a second excitation coil 20 is installed inside the second inner and outer yokes 24.25 via a bobbin 27. A coil 21 is attached.

The bobbin 26.27 is made of an insulating material such as plastic, and parts 26A and 27A of the bobbin 26.27 protrude from the side surface of the motor case 10. Motor one terminal member 28
．． 29 (4 or 6 in total) are led out.

A rotational force extraction means such as a pulley is fixed to the output side protrusion of the motor shaft 17.

An encoder 31 for detecting the angle and speed of rotation of the motor is attached to the outside of the motor case 10 on the side opposite to the output side of the motor.

This encoder 31 consists of a coding disk (slint circle 1 in the illustrated example) 3 that is positioned and fixed on the motor shaft 17.
2 and a sensor (photointerrupter in the illustrated example) 33 that is positioned and fixed on the outer surface of the motor case 10.

The sensor 33 is connected to the motor one terminal member 28.29.
The sensor terminal member 34 of the sensor 33 (consisting of a total of four encoder terminal members for power supply and signal use in the illustrated example) is located on the same side as the motor terminal member 28 and 29. They protrude in approximately the same direction.

Each of the terminal members protruding on substantially the same side in the circumferential direction of the motor, that is, a total of four or six motor terminal members 28, 29 and a total of four sensor terminal members 34, has a predetermined shape. It is made of rigid, conductive rod-shaped or plate-shaped metal.

Therefore, the motor one terminal members 28, 29 and the sensor one terminal member 34 are all fixed to the same substrate 35, and all the terminals formed at their tips, that is, the motor one terminals 28A, 29A. and sensor terminal 3
4A is provided on this common substrate 35.

The sensor 33 connects positioning protrusions (not shown) formed at two locations on the mating surface to the motor case 10.
Positioning holes (not shown) formed at two locations on the end surface of
At the same time, screws 3 are inserted into female threads 37 formed by tapping (thread processing) on the inner diameter of the motor case 10 by burring at the other two locations.
By fastening at 8, the position is fixed.

On the other hand, the motor shaft 17 has a receiving surface 3 perpendicular to the shaft center.
A plastic receiving member 39 having a diameter of 9A is press-fitted and fixed at a predetermined position in the axial direction, and the coded disk 32 whose center hole is press-fitted into the motor shaft 17 is also pressed against the receiving surface 39A of the receiving member 39. It is pressed into contact with a press-fitted spring press ring 40, and is positioned and fixed.

The retainer ring 40 includes a spring portion 40 that is inclined in a direction to prevent removal and whose tip end is press-fitted into the motor shaft 17.
A and a flat annular plane portion 40B for evenly pressing the coded disc 32 against the receiving surface 39A.

That is, the coded disc 32 ensures coaxiality with the motor shaft 17 by press-fitting the center hole formed in itself, and also has spring properties with the receiving surface 39A of the receiving member 39. By being pressed between the retainer ring 40 and the retainer ring 40, the surface angle and axial position relative to the motor shaft 17 are accurately ensured.

A dustproof cover 36 for covering the encoder 31 is removably attached to the outer peripheral surface of the motor case 10.

This dustproof cover 36 is made of plastic molding, and is detachably fixed to the motor case 10 by a concave-convex engagement means (not shown) that utilizes its elasticity.

The dustproof cover 36 prevents the code portion (slits, striped patterns, etc.) formed on the coded disk 32 from becoming clogged with dust, making feedback control of the rotation angle of the stepping motor unstable and inaccurate. This is to prevent

FIG. 2 is a longitudinal sectional view showing a press-fitting process for positioning and fixing the coded disk (slit disk, etc.) 32 to the motor shaft 17.

In FIG. 2, a press-fitting jig 45 for positioning and fixing the coding disk 17 includes a movable mold 46 fixed to a movable part of a press machine, and a fixed mold 47 fixed to a fixed part of the press machine. It consists of

These movable mold 46 and fixed mold 47 are arranged in a coaxial position.

Therefore, the motor body (the motor assembly before attaching the encoder 31 or the coding disc 32) is attached to the movable mold 46, and the holding ring 40, the coding disc 32, and the With the receiving members 39 overlapped! ! After placing the motor body, the motor shaft 17 is attached to these members 39.
32 and 40 and is pushed down to a predetermined position in the axial direction, the coding disk 32 is positioned and fixed.

In the illustrated example, the movable mold 46 is provided with a hole 48 that fits into the pulley 30 of the motor body and a pin 49 for pressing down the tip of the motor shaft 17.

Meanwhile, a guide hole 50 is formed in the fixed mold 47 for guiding the outer peripheral surface of the motor case 10 of the motor body.

Further, at the center of the bottom of the guide hole 50, the receiving member 39, the coded disc 32, and the holding ring 40 are positioned and mounted, and a center guide portion having an inner diameter into which the tip of the motor shaft 17 fits. 51 are provided.

According to the press-fitting jig 45 shown in FIG. 2, the holding ring 40, the coded disk 32, and the receiving member 39 are placed in an overlapping state on the guide portion 51 in the fixed mold 47, and the motor body is set. The coding disc 32 can be positioned and fixed on the motor shaft 17 by simply rolling down the movable mold 46 to a predetermined position in the axial direction.

In that case, the coded disk 32 is coaxially controlled by its own center hole, perpendicularity is controlled by the receiving surface 39A of the receiving member 39 and the press ring 40, and the press-fitting position of the receiving member 39 ( Since the axial position is regulated by the amount of reduction regulated by a stopper or the like, positioning and fixing can be achieved only by the press-fitting process.

Note that the retaining ring 40 is provided with the spring portion 40A that tapers in the direction of preventing removal, so that it is possible to prevent springback after press-fitting, and to accurately position the coded disk 32 in the axial direction. can be regulated.

Further, since the annular flat portion 40B having a completely circular shape is provided on the outer circumferential portion of the holding ring 40, the coded disk 32 can be uniformly pressed against the receiving surface 39A, and the coded disk The squareness and flatness of the plate 32 can be easily maintained.

In the above embodiments, the encoder mounting method of the present invention was applied to a stepping motor, but the present invention can be similarly applied to other types of motors as long as they are small motors. and similar effects can be achieved.

〔Effect of the invention〕

As is clear from the above description, according to the method for attaching a motor encoder of the present invention, a center hole is formed in the coding disk to be press-fitted with the motor shaft, and the tip is inclined in the axial direction to prevent the motor from coming off. A retainer ring having a spring portion and a flat outer circumference that is press-fitted onto the shaft, and a receiving member that has a receiving surface perpendicular to the motor shaft and is press-fitted to the motor shaft, and the outer circumference of the retainer ring is and the receiving surface of the receiving member, sandwiching the coded disc between these three
Since the two members are simultaneously press-fitted and positioned on the motor shaft, the number of man-hours required to attach a coding disk such as a slit disk to the motor shaft can be significantly reduced.
A method for attaching an encoder to a motor is provided that can simplify the structure and reduce costs.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view illustrating a motor suitable for carrying out the encoder mounting method according to the present invention, and FIG. 2 is a longitudinal sectional view showing steps for carrying out the encoder mounting method according to the present invention. Below, symbols representing main components in the drawings are listed. 1 (1----Motor case, 12・-1----
Mounting plate, 17--motor shaft, 18--1---
Rotor, 20.21--Single moving magnetic coil, 22.23.
24.25 Yoke, 28.29---Motor one terminal member, 31-1111 encoder, 32---Coding disk (slit disk), 33---------Sensor ( Photo interrupter), 34---Encoder one terminal, 35 Board, 36---Dust cover, 37---
Female screw, 38- Screw, 39--One receiving member, 39
A-1111 receiving surface, 40-pressing ring, 40
A-----Spring part, 40B--Annular plane part, 45
---One press fit jig, 46 movable type, 47- fixed type, 50
------Guide hole, 51--center guide part.

Claims (1)

[Claims] (1) A retaining ring that has a center hole formed in the coded disc to be press-fitted with the motor shaft, a spring part that is inclined in the axial direction to prevent it from coming off, and whose tip part is press-fitted into the motor shaft, and a flat outer peripheral part. , using a receiving member having a receiving surface perpendicular to the motor shaft and press-fitted to the motor shaft, and placing the coded disk between the outer periphery of the holding ring and the receiving surface of the receiving member. A method for attaching an encoder to a motor, which is characterized by simultaneously press-fitting and positioning these three members onto the motor shaft by sandwiching them.