JPH1198751A - Motor, and its setup method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high-performance motor which enhances accuracy in centering of a rotor and is thinned, and its setup method. SOLUTION: A rotor shaft 17 is supported by a front bearing 1 and a rear bearing 12. The rear bearing 12 is fixed so as not to project from the bottom of a rear plate 14. The bottom of the rotor shaft 17 is positioned in the middle of a shaft hole of the rear bearing 12, and a vacant space 11 is made under it. At setup, the centering of the rotor shaft 17 is performed, by setting the vacant space 11 of the rear bearing 12 on the guide pin 26 erected on a lower jig 25, and the outside periphery of front bearing 1 in the upper guide hole 22 of an upper jig 20.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a motor such as a PM type stepping motor and a method for assembling the same.

[0002]

2. Description of the Related Art FIG.
It is shown in the side sectional view of FIG. In FIG. 1, reference numeral 1 denotes a front bearing, which is fixed to a front plate 3; and 2, a rear bearing, which is fixed to a rear plate 4 by press-fitting or caulking. Reference numeral 7 denotes a rotor shaft which is supported by the pair of front bearings 1 and rear bearings 2 and rotates. When assembling this motor, as shown in FIG. 3B, necessary components shown in FIG. 4 are placed on the lower jig 21 by a rear assembly 30, a slider 31, a spring 32, a rotor 33, a slider 31, a front assembly 34. After loading and inserting in the order of, the upper jig 20 is covered,
The outer peripheral portion of the front bearing 1 fits into an upper guide hole 22 as a position determining means of the upper jig 20, and the outer peripheral portion of the rear bearing 2 fits into a lower guide hole 23 as a position determining means of the lower jig 21. Then, the centering of the rotor 33 and confirmation of the axial gap are performed. Then, the front plate 3 is fixed to the outer yoke 5 of the rear assembly 30 by welding or the like, and the assembly is completed. The rear assembly 30 is an intermediate assembly part in which centering between the inner circumferences of the outer yoke 5 and the inner yoke 6 containing the pair of coils 10 and the shaft hole of the rear bearing 2 has been completed in advance, and fixedly formed by welding or the like. The front assembly 34 is an intermediate assembly in which the front bearing 1 is fixed to the front plate 3 in advance.

[0003]

However, the motor according to the conventional configuration described above has a smaller size, a higher performance,
The demand for lower prices has tended to increase in recent years.
It has been desired to improve the performance by increasing the centering accuracy of the rotor while reducing the thickness.

Accordingly, the present invention focuses on a bearing structure of a motor in order to solve the above-mentioned problems of the prior art, and does not project a bearing portion from an outer surface of the motor, and furthermore, a shaft of the bearing. It is an object of the present invention to provide a motor capable of reducing the thickness of the motor by using the holes as a reference at the time of assembling the motor, and further improving the centering accuracy of the rotor and improving the performance, and a method of assembling the motor.

[0005]

Means for Solving the Problems In order to achieve the above object, the present invention provides a motor having a rotor shaft rotatably supported by a pair of bearings. However, the other bearing does not support the rotor shaft in the entire range of the shaft hole, the rotor shaft end is located in the middle of the shaft hole, and the remaining portion is a gap. The gap is fitted to the position determining means of the assembly jig.

According to the present invention, since the rotor is configured as described above, the centering accuracy between the rotor and the yoke is improved by one rank, which contributes to higher performance of the motor and protrudes from the outer surface of the motor. By moving the effective portion of the bearing into the interior, it is possible to achieve a reduction in thickness.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. In addition, the code in the drawing
The same parts as those in the conventional example are denoted by the same reference numerals. FIG. 1A is a side sectional view of an embodiment of the motor according to the present invention. Referring to FIG. 1, reference numeral 1 denotes a front bearing, which is a conventional structure fixed to the front plate 3 by press-fitting or caulking. The rear bearing 12 has a rear plate having a central portion formed slightly inward of the motor. 14 is fixed to the center hole of the motor by press-fitting, caulking, etc.
The rear bearing 12 does not protrude from the bottom surface of the rear plate 14 and retains most of its effective portion inside the motor. Further, the end of the rotor shaft 17 on the side supported by the rear bearing 12 does not protrude from the shaft hole of the rear bearing 12 as shown in FIG. 1
1 are formed.

When assembling this motor, FIG.
As shown in (b), first, necessary components shown in FIG. 2 are stacked and inserted on the lower jig 25 in the order of the rear assembly 35, the slider 31, the spring 32, the rotor 36, the slider 31, and the front assembly 34. Here, the gap 11 formed in the rear bearing 12 of the rear assembly 35 is fitted to a guide pin 26 as a position determining means protruding from the lower jig 25. By further covering the upper jig 20, the outer peripheral portion of the front bearing 1 is
Is fitted into the upper guide hole 22 as the position determining means, and the centering of the rotor 36 and the check of the axial gap are performed. Finally, the front plate 3 is fixed to the outer yoke 5 of the rear assembly 35 by welding or the like and assembled. Is completed. Note that the front assembly 34 and the rear assembly 35 are intermediate assembly parts, and are manufactured by substantially the same process as in the related art, and will not be described here.

As described above, when centering the rotor at the time of assembling the motor according to the present invention, instead of fitting the outer peripheral portion of the rear bearing into the guide hole of the lower jig as in the related art, In order to fit the gap 11 formed in the shaft hole of the rear bearing 12 to the guide pin 26 of the lower jig 25, the effect of the eccentric error between the outer peripheral portion of the rear bearing and the shaft hole is eliminated. Therefore, the centering accuracy between the outer periphery of the permanent magnet 9 of the rotor 36 and the inner periphery of the outer yoke 5 and the inner yoke 6 is improved, and the performance of the motor is further improved.

Further, the outer peripheral portion of the rear bearing 12 is fixed to the rear plate 14 and does not protrude from the bottom surface as in the related art, so that the thickness of the motor can be reduced accordingly. The effective portion of the rear bearing 12 extends to the inside of the motor, where the rotor shaft 17 that supports the rotational load of the rotor 36 slides, and the gap 11 that fits into the guide pin 26 of the lower jig 25 during assembly. Is set to a sufficient length, so that the collar 18 of the rotor 36 is shortened by the space as compared with the related art, but there is no problem in performance as a motor.

[0011]

As described above, according to the present invention, the following effects can be obtained. In one bearing of a motor having a rotor shaft rotatably supported by a pair of bearings, one end of the rotor shaft is located in the middle of the shaft hole, and a gap is formed in the shaft hole. The centering accuracy of the rotor of the motor is further improved by adopting a configuration in which the gap is fitted to the position determining means of the assembly jig and the effective part of the bearing that has protruded from the outer surface of the motor has been moved inside. In addition, it is possible to provide a high-performance motor with extremely small noise and vibration and further reduction in thickness, and an assembling method thereof.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing an embodiment of a motor according to the present invention and a side sectional view showing a relationship between an assembling jig and components of the motor in a method of assembling the motor.

FIG. 2 is a side sectional view of each assembly part constituting the motor according to the present invention.

FIG. 3 is a side sectional view showing an embodiment of a conventional motor and a side sectional view showing a relationship between an assembly jig and components of the motor in a method for assembling the motor.

FIG. 4 is a side cross-sectional view of each assembly part constituting a conventional motor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Front bearing 3 Front plate 11 Gap part 12 Rear bearing 14 Rear plate 17 Rotor shaft 20 Upper jig 22 Upper guide hole 25 Lower jig 26 Guide pin 34 Front assembly 35 Rear assembly 36 Rotor

Claims (2)

[Claims] 1. A motor having a rotor shaft rotatably supported by a pair of bearings, wherein one end of the rotor shaft is located in the middle of a shaft hole of one of the bearings. A motor, wherein a gap is provided in the motor. 2. A method for assembling a motor according to claim 1, further comprising a rotor shaft rotatably supported by a pair of bearings, wherein a gap in a shaft hole of one of the bearings is set in a motor assembly jig. A motor assembling method, wherein the motor is fitted to the position determining means.