JPH0442749A - Motor sensor fixing structure - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a sensor mounting structure for positioning and fixing a sensor to a motor case side with respect to a coding disk on a motor shaft in a stepping motor or the like. .

[Prior art] Motors such as stepping motors are equipped with an encoder 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 to prevent slippage, especially during high-speed rotation. Measures are being taken to prevent rotational accuracy from decreasing due to rotational adjustment.

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 a conventional encoder-equipped motor, a sensor such as a photointerrupter is generally positioned and fixed on a mounting plate fixed to a motor case by fastening means such as screws.

[Technical Problem to be Solved by the Invention] However, in such a conventional motor encoder sensor mounting structure, in addition to the positional tolerance between the motor case and the motor shaft, there is also a difference in the positional tolerance between the motor case and the mounting plate. There was a technical problem in that it was difficult to sufficiently improve the detection accuracy of the motor rotational position because positional tolerances were accumulated between the coding disk and the sensor, and the accumulated error in the relative position between the coding disk and the sensor became large.

The present invention has been made in view of these technical problems, and it is possible to easily improve the accuracy of the mounting position of a sensor such as a photo ink clubtor with respect to the coding disk on the motor shaft, and to make it simple. It is an object of the present invention to provide a sensor mounting structure for a motor that can fix a sensor with an inexpensive structure.

[Means for solving problems]

The sensor mounting structure of the present invention is such that in a motor having a coded disc fixed to a motor shaft and a sensor fixed to a motor case, the sensor can be mounted by a positioning hole formed in the motor case and a mounting part. By positioning and fixing the sensor to the motor case, it is possible to easily improve the accuracy of the mounting position of the sensor such as the photoink clubtor with respect to the coding disk on the motor shaft, and the sensor can be mounted with a simple and inexpensive structure. The present invention provides a motor sensor mounting structure that can fix the motor.

〔Example〕

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

FIG. 1 is a longitudinal cross-sectional view showing the structure of a stepping motor incorporating a sensor mounting structure according to the present invention.

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 plate 12.

The mounting plate 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 attached to the inside of the first inner and outer yokes 22.23 via a pobbin 26, and a second excitation coil 20 is attached to the inside of the second inner and outer yokes 24.25 via a pobbin 27. A coil 21 is attached.

The pobbins 26 and 27 are made of an insulating material such as Plasti-2, and parts 26A and 27A of the pobbins protrude from the side surface of the motor case 10, and the excitation coils 20 and 21 are attached to the protrusions. motor-terminal member 2 connected to
8.29 (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 shafts 1 and 7.

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 includes a coding disk (a slit disk in the illustrated example) 3 that is positioned and fixed on the motor shaft 17.
2 and a sensor (photo ink probe 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.

On the motor shaft 17, a plastic bearing member 39 having a carefully perpendicular bearing surface 39A is press-fitted and fixed in a predetermined position in the axial direction, and a coded disc whose center hole is press-fitted into the motor shaft 17. 32, the receiver of the receiver member 39 is pressed against the surface 39A by a spring presser ring 40 which is also press-fitted, 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 disk 32 against the receiving surface 39A.

That is, the coded disk 32 is press-fitted into the center hole formed in itself to ensure coaxiality with the motor shaft 17, and furthermore, the receiver of the member 39 has a spring property with the surface 39A. The surface angle and axial position with respect to the motor shaft 17 are accurately ensured by being pressed between the retainer ring 40 and the retainer ring 40 having a diameter.

On the other hand, as will be described later, the sensor 33 has positioning protrusions formed at two locations on the mating surface thereof fitted into positioning holes formed at two locations on the end surface of the motor case 10, and The other two locations are positioned and fixed by a female screw 37 tapped into the burring portion of the motor case 10 and a screw 38 fastened to the female screw.

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 coded portion (slit pattern, striped pattern, etc.) formed on the coded disk 32 of the dustproof cover 36 becomes clogged with dust, etc., and the feedbank control of the rotation angle of the stepping motor becomes unstable and inaccurate. This is to prevent this from happening.

FIG. 2 is a plan view of the motor case 10 seen from the open end side, FIG. 3 is a longitudinal sectional view taken from the line ■■ in FIG. 2, and FIG. -) 33 as seen from the mounting surface side, and FIG. 5 is a side view seen from the line TV--TV in FIG. 4.

The mounting structure of the sensor 33 will be described below with reference to FIGS. 2 to 5.

2 to 5, the mounting surface of the sensor 33 is formed with positioning protrusions 52 (two locations) and mounting elongated holes 53 (two WJ locations).

On the other hand, the sensor 3 is mounted on the end face of the motor case 10.
The positioning hole 5 corresponds to the protrusion 52 and the elongated hole 53 of 3.
4 and a burring 55 are formed.

The positioning holes 54 are formed at two locations at a predetermined interval in the radial direction of the motor, and are formed on both sides of a line connecting the positioning holes 54 at the two locations of the burring 55.

The screws 37 (FIG. 1) are formed on the inner diameter of each bur ring 55 by tapping, and the screws 37 (FIG. 1) are formed by tapping.
8 (FIG. 1), the sensor 33 is positioned and fixed on the outside of the end surface of the motor case 10 by fastening the portions of each of the elongated holes 53.

That is, in this embodiment, the two projections 52 are fitted into the two positioning holes 54, and the two elongated holes 53 are fitted into the two long holes 53 on both left and right sides (approximately on both sides in the circumferential direction). The sensor 33 is configured to be directly positioned and fixed to the motor case 10 by fitting into the bar ring 55 and screwing the screw 38 from above each elongated hole 53 to the female thread 37 in each bar ring 55. ing.

According to the embodiment described above, the sensor 33 of the encoder 31 is directly attached and positioned and fixed to the motor case IO, so that it is possible to reduce the accumulation error with respect to the coding disk 32 fixed to the motor shaft 17. This makes it possible to easily improve the relative positional accuracy (coaxiality, flatness, axial position, etc.) between the sensor 33 and the coding disk 32.

Furthermore, unlike in the past, separate members such as a mounting plate are not required, so the number of parts and processing steps are reduced, making it possible to downsize the motor and reduce costs.

In addition, the reference numeral 56 in FIGS. 2 and 3 indicates bar rings (3 locations) for caulking and fixing the first outer yoke 22 to the inner side of the end surface of the motor case IO.
Reference numeral 7 indicates a notch for causing the motor terminal members 28 and 29 to protrude to the outside of the motor case 10.

In the above embodiments, the case where the sensor mounting structure of the present invention is applied to a stepping motor has been described, but the present invention can be similarly implemented in other types of motors as long as they are small motors. Similar effects can be achieved.

Furthermore, the present invention can be widely implemented regardless of the type of sensor that constitutes the encoder, such as a photo ink converter, a reflective photoelectric sensor, or a magnetic sensor, and can achieve similar effects. It's something you get.

Further, in the above embodiments, the positioning hole 54 is formed as a through hole, but it may be formed as a recessed hole that does not penetrate as long as it forms a concave-convex fit that allows positioning.

Furthermore, in the above embodiment, the positioning protrusion 52, the fitting hole 54, the mounting hole 53, and the burring 5
5 are provided at two locations each, but these may be provided at one location, or may be three or more locations, and their positions, shapes (especially the shapes of positioning holes and protrusions), and numbers are determined as appropriate. be able to.

(Effects of the Invention) As is clear from the above description, according to the motor sensor mounting structure of the present invention, in a motor having a coded disc fixed to the motor shaft and a sensor fixed to the motor case, The sensor is positioned and fixed to the motor case using the positioning hole formed in the case and the mounting part.
Provided is a sensor mounting structure for a motor that can easily improve the accuracy of the mounting position 1 of a sensor such as a photo ink clubtor with respect to a coded disk on a motor shaft, and can also fix the sensor with a simple and inexpensive structure. Ru.

[Brief explanation of drawings]

Fig. 1 is a vertical cross-sectional view showing an example of the structure of a motor having a sensor mounting structure according to the present invention, Fig. 2 is a front view of the motor case in Fig. 1, and Fig. 3 is a line - - - in Fig. 2. 4 is a bottom view of the sensor in FIG. 1, and FIG. 5 is a side view taken from line V--■ in FIG. 4. Below, symbols representing main components in the drawings are listed. 10----Motor case, 12----One mounting plate, 17----Motor shaft, 18----One rotor, 20.21----Excitation coil, 22.23
．． 24.25 yoke, 28.29-motor one terminal member,
31-1 encoder, 32-m-encoding disk (slit disk), 33----sensor (photo ink converter), 34-1 encoder one terminal, 35 board,
36---Dust-proof cover, 37--female screw (sensor installation), 38---screw (sensor installation), 39
-・-11--Receiver is member, 40...--Press ring, 52...-11--Protrusion for positioning, 53--
---Hole for mounting (long hole L54--Positioning hole (positioning hole), 55--Burring.

Claims (1)

[Claims] (1) In a motor having a coded disc fixed to the motor shaft and a sensor fixed to the motor case, the sensor is positioned in the motor case by a positioning hole and a mounting part formed in the motor case. A motor sensor mounting structure characterized by being fixed.