JPH08103049A - Motor and its assembly method - Google Patents

Abstract

PURPOSE: To provide a method of assembling a motor by which the assembling can be performed, avoiding cost up. CONSTITUTION: A spring whose diameter is larger than the inside diameter of the bearing retaining recess 9b of a second cover 9 is larger than its outside diameter is used as a pressure spring 14. A second spring 11 is inserted into the bearing retaining recess 9b of a second end cover 9, in condition that the pressurizing spring 14 is press-fit and locked in the bearing retaining recess 0b of the second end cover 9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric motor having a structure in which a rotary shaft is supported by bearings on end covers for closing both ends of a cylindrical stator yoke, and an assembling method thereof.

[0002]

2. Description of the Related Art In this type of electric motor, a stator is composed of a cylindrical stator yoke and a fixed field attached to the inner circumference of the stator yoke, and a rotor is provided inside the stator. Are placed. One end side and the other end side in the axial direction of the stator yoke are closed by a first end cover and a second end cover, respectively, and the stator yoke and the first and second end covers are closed.
The housing of the electric motor is constituted by the end cover of.

One end and the other end of the rotary shaft supporting the rotor are supported by a first bearing and a second bearing attached to the first end cover and the second end cover, respectively. One end serves as an output end and extends through the first end cover to the outside.

In this type of electric motor, the outer ring of the first bearing is fixed to the first end cover in order to prevent the outer ring of the first bearing supporting the output end side of the rotary shaft from creeping. Also, in order to facilitate the assembly of the electric motor, the second bearing is slidably inserted into the bearing holding recess provided in the second end cover,
A preload spring composed of a wave washer is arranged in the bearing holding recess, and the outer ring of the second bearing is biased toward the first bearing by the preload spring.

This type of electric motor was assembled in the following manner.

That is, after the first bearing and the second bearing are attached to both ends of the rotary shaft holding the rotor, the first bearing is inserted into the recess of the first end cover to mount the rotor. An assembly is formed by integrating the held rotating shaft and the first end cover.

Next, the assembly is placed on the assembly work table with the first end cover down and the rotation axis in the vertical direction.

Next, one end of the stator yoke is fitted on the outer circumference of the first end cover.

Next, as shown in FIG. 4, the second bearing 11 is attached to the second bearing 11 mounted on the rotary shaft 5 with the preload spring 14 formed of a wave washer being placed on the second bearing 11. Bearing holding recess 9b of the end cover 9 of
The second end cover 9 is inserted into the inside and attached to the other end of a stator yoke (not shown).

When assembling in this way,
When the outer diameter of the second bearing 11 is D1, the outer diameter of the preload spring 14 is D2, and the inner diameter of the bearing holding recess 9b is D3, these dimensional relationships are set to D2 <D1 ≤ D3.

However, in such an electric motor assembling method, the preload spring 14 mounted on the second bearing 11 moves a little during the assembling so that the preload spring 14 moves to the second position.
If it protrudes from the outer periphery of the bearing 11, the second end cover 9 cannot be attached, and the position of the preload spring 14 is corrected again, which is not suitable for mass production of electric motors.

Therefore, the present applicant has proposed an electric motor having a structure suitable for mass production as shown in FIG. 5 (Japanese Patent Application No. 4-79).
099).

This electric motor is provided with a cylindrical stator yoke 1, a fixed field 2 made of a permanent magnet is fixed to the inner circumference of the stator yoke 1, and the stator yoke 1 and the fixed field 2 form a fixed field. The stator 3 is configured.

Inside the stator 1, a rotor 4 is provided concentrically with the stator. The rotor 4 has an armature winding 7 in a slot of a rotor core 6 supported by a rotating shaft 5.
It consists of a wound.

A first end cover 8 and a second end cover 9 that close one end side and the other end side of the stator yoke 1 are provided at both ends of the stator yoke 1 in the axial direction. A first bearing 10 held by each of the first end cover 8 and the second end cover 9
The rotating shaft 5 is supported by the second bearing 11. First bearing 10 and second bearing 11
Each of them comprises a well-known ball bearing in which a ball is held between an inner ring and an outer ring, and a rotary shaft 5 is press-fitted into each inner ring 10a, 11a.

The first end cover 8 is formed in a disk shape, and an annular spigot portion 8a is projectingly provided at a position near the outer periphery of the inner end surface of the first end cover 8, and the spigot portion 8a is provided at one end of the stator yoke 1. It is fitted to the inner circumference. The first end cover 8 is provided with a recess 8b that opens to the inner end surface thereof, and the outer ring 1 of the first bearing 10 is provided in the recess 8b.
0b is fitted, one end of the rotary shaft 5 is the output end 5a,
It penetrates through the first end cover 8 and is led out to the outside. A bearing pressing plate 12 is fixed to the inner end surface of the first end cover 8 with a screw 13, and the outer ring 10b of the first bearing 10 is fixed so as not to rotate by the bearing pressing plate 12.

The second end cover 9 is formed in a cup shape, and has an annular spigot portion 9a provided so as to project in the axial direction from a portion of the peripheral wall portion of the end cover 9 near the inner periphery of the open end surface. Is fitted to the inner circumference of the other end of the stator yoke 1. A bearing holding recess 9b is formed in the center of the bottom wall of the second end cover 9, and the outer ring 11b of the second bearing 11 is slidably fitted in the bearing holding recess 9b. Bearing holding recess 9
A preload spring 14 is arranged at a position near the bottom in b, and a washer holding plate 15 is arranged between the preload spring 14 and the second bearing 11.

In this case, the preload spring 14 has a thickness of 0.3 mm.
Made of spring steel, the washer holding plate 15 has a thickness
It is made of brass plate of about 0.05 mm. FIG. 6 (A),
As shown in (B), the washer holding plate 15 is formed by forming three protrusions 15a at 120 degree intervals on the outer peripheral portion of a ring-shaped plate, and the outer diameter r of the ring-shaped portion is the bearing holding recess. It is set to be substantially equal to the inner diameter of 9b, and the distance r'from its center to the tip of the projection 15a is set to be larger than the inner diameter of the bearing holding recess 9b. The washer holding plate 15 is inserted into the recess 9b after the preload spring 14 is inserted into the bearing holding recess 9b. When the washer holding plate 15 is inserted into the bearing holding recess 9b, the protrusion 15a is bent to the side opposite to the preload spring 14 and comes into frictional contact with the inner circumference of the recess 9b. The washer holding plate 15 is held in the concave portion 9b by the contact of.

A commutator 16 connected to the armature winding 7 is attached to the other end of the rotary shaft 5, and a brush 18 held in a brush holder 17 attached to the second end cover 9 is commutated. It is in contact with the child 16.

A through bolt 19 inserted into a hole provided in the bottom wall portion of the second end cover 9 is screwed into a screw hole provided in the first end cover 8 through the inside of the stator yoke 1. The through bolts fasten the second end cover 9, the stator yoke 1 and the first end cover 8 to assemble the electric motor.

In assembling the above-mentioned electric motor, the commutator 16 and the bearing 10 are attached to the rotary shaft 5 holding the rotor 4.
, 11 and, the outer ring of the first bearing 10 is inserted into the recess 8b of the first end cover 8, the bearing retainer plate 12 is further attached, and the rotating shaft 5 holding the rotor 4 and The end cover 8 of No. 1 is integrated to form an assembly. Further, the preload spring 14 and the washer holding plate 1 are previously provided in the bearing holding recess 9b of the second end cover 9.
Insert 5 and.

In this state, the assembly is placed on the assembly work table with the first end cover 8 facing downward and the rotary shaft 5 oriented in the vertical direction. One end of the stator yoke 1 is fitted into the portion 8a.

Then, the spigot portion 9a of the second end cover 9 is fitted to the other end of the stator yoke 1, and the outer ring 11b of the second bearing 11 is inserted into the bearing holding recess 9b of the second end cover. At the same time, the brush 18 is brought into contact with the commutator 16.

After that, the second end cover 9, the stator yoke 1 and the first end cover 8 are fastened with the through bolts 19 to complete the assembly of the electric motor.

When the second end cover 9 is fitted to the other end of the stator yoke 1, the opening of the bearing holding recess 9b faces downward, but the washer holding plate 15 is placed in the bearing holding recess 9b. Since the washer holding plate 15 is inserted and the preload spring 14 is prevented from falling off, there is no risk of the preload spring 14 dropping when the second end cover 9 is attached.

When the electric motor is assembled, the preload spring 14
Although the washer holding plate 15 is interposed between the preload spring 14 and the outer ring 11b of the second bearing 11, the washer holding plate 15 is made of a material that is sufficiently thinner than the preload spring 14, and thus the preload spring 14 and the Since the second bearing 11 is easily deformed by following the axial displacement of the second bearing 11, the transmission of the spring force from the preload spring 14 to the second bearing 11 is not hindered.

[0027]

However, in such a method of assembling the electric motor, the washer holding plate 15 is required to lock the preload spring 14 in the bearing holding recess 9b of the second end cover 9 during assembly. Therefore, the number of parts is increased, the number of assembling steps is increased, and the cost is increased.

An object of the present invention is to provide an electric motor having a structure capable of reducing cost.

An object of the present invention is to provide an assembling method of an electric motor which can be assembled while avoiding an increase in cost.

[0030]

SUMMARY OF THE INVENTION According to the present invention, a stator having a stator field attached to the inner circumference of a cylindrical stator yoke, and a first end for closing one end side of the stator yoke in the axial direction. One end side is supported by a cover, a second end cover that closes the other end of the stator yoke, and a first bearing fixed to the first end cover, and a bearing holding provided on the second end cover. A rotary shaft whose other end is supported by a second bearing inserted in the recess, a rotor arranged inside the stator and attached to the rotary shaft, and a rotary shaft arranged in the bearing holding recess. An electric motor having a structure including a preload spring for urging the second bearing toward the first bearing is targeted for improvement.

In the electric motor according to the present invention, the preload spring whose outer diameter is larger than the inner diameter of the bearing holding recess of the second end cover is used, and the preload spring is a bearing of the second end cover. It is characterized in that it is arranged in the holding recess with its outer diameter compressed.

Further, according to the present invention, the first bearing and the second bearing are attached to both ends of the rotary shaft holding the rotor, and then the first bearing is inserted into the recess of the first end cover. An assembly in which the rotary shaft holding the rotor and the first end cover are integrated is formed, the assembly is placed with the first end cover downward, and the rotary shaft is oriented in the vertical direction. Place it on the assembly workbench in the state,
One end of the stator yoke is fitted to the outer circumference of the first end cover, then the outer circumference of the second end cover is fitted to the other end of the stator yoke, and the second bearing is attached to the first end cover. An object of the present invention is to improve an assembling method of an electric motor in which the second bearing is inserted into a bearing holding recess of the second end cover through a preload spring biased to the bearing side for assembling.

In the method of assembling the electric motor according to the present invention, the preload spring having an outer diameter larger than the inner diameter of the bearing holding recess of the second end cover is used, and the bearing holding recess of the second end cover is used. The second bearing is inserted into the bearing holding recess of the second end cover in a state where the preload spring is press-fitted and locked therein.

[0034]

As described above, the preload spring whose outer diameter is larger than the inner diameter of the bearing holding recess of the second end cover is used, and the outer diameter of the preload spring is set in the bearing holding recess of the second end cover. When placed in a compressed state,
Since the preload spring itself can be engaged with the bearing holding concave portion, the washer holding plate which is conventionally required is not required.

Therefore, the number of parts can be reduced, the number of assembling steps can be reduced, and the cost can be reduced.

[0036]

EXAMPLES Examples of the present invention will be described below with reference to FIGS.
This will be described in detail with reference to (C).

1A and 1B and FIG. 2 show an embodiment of an electric motor and an assembling method thereof according to the present invention.

In this embodiment, the preload spring 14 shown in FIG.
A spring ring such as a steel wire ring, a stainless wire ring, a brass wire ring, etc., of which a part is opened as shown in (A) and (B) is used, and the preload spring 14 made of this spring ring has both ends facing the opening shown. The structure is such that they are displaced in opposite directions. In addition, the preload spring 14
The outer diameter D4 is the inner diameter D3 of the bearing holding recess 9b.
It is set to be larger. That is, D3 <D4. In this embodiment, D1≤D3.

As shown in FIG. 2, the preload spring 14 is preliminarily press-fitted into the bearing holding recess 9b of the second end cover 9 with its outer diameter being compressed to be engaged with the second bearing. 11 is inserted into the bearing holding recess 9b of the second end cover 9.

Other structures and assembling methods are the same as in the case of FIG. 5 described above.

FIGS. 3A, 3B and 3C show the preload spring 14
The other three examples are shown. In all of these three examples, the preload spring 14 has an outer diameter of the second end cover 9
It is set to be larger than the inner diameter of the bearing holding recess 9b.

The preload spring 14 shown in FIG. 3 (A) is similar to the case of FIG. 1 in that it is composed of a spring ring such as a steel wire ring, a stainless wire ring, and a brass wire ring, which are partially opened. In the example, this spring ring has a wavy washer.

The preload spring 14 shown in FIG. 3B has a structure in which both ends of a spring ring such as a steel wire ring, a stainless wire ring and a brass wire ring are overlapped with a predetermined length. Also in this example, the preload spring 14 has a structure in which the spring ring is corrugated as a wave washer.

The preload spring 14 shown in FIG. 3 (C) is mainly composed of a spring ring 14a such as a brass plate ring which is corrugated to form a wave washer, and a plurality of protrusions 14b are provided on the outer circumference of the spring ring 14a. The outer diameter passing through the tips of the protrusions 14b is set to be larger than the inner diameter of the bearing holding recess 9b. The outer diameter of the spring ring 14a is set to be equal to or smaller than the inner diameter of the bearing holding recess 9b.

In the above embodiment, the case where the first end cover 8 and the stator yoke 1 are separate bodies has been described, but the present invention is not limited to this, and the end of the stator yoke 1 is not limited to this. The same can be applied to the type in which the first end cover 8 is integrated in the part.

[0046]

As described above, in the electric motor and the method for assembling the same according to the present invention, a preload spring having an outer diameter larger than the inner diameter of the bearing holding recess of the second end cover is used. Since the outer diameter of the second end cover is arranged in the bearing holding concave portion in a compressed state, the preload spring itself can lock the bearing holding concave portion, and thus the washer holding plate conventionally required is not necessary. Become.

Therefore, according to the electric motor and its assembling method of the present invention, the number of parts can be reduced, the number of assembling steps can be reduced, and the cost can be reduced.

[Brief description of drawings]

1A and 1B are a plan view and a side view of an example of a preload spring used in a method of assembling an electric motor according to the present invention.

FIG. 2 is a cross-sectional view showing a main process of an electric motor assembling method according to the present invention.

3 (A), (B) and (C) are perspective views showing other three types of preload springs used in the method of assembling the electric motor according to the present invention.

FIG. 4 is a cross-sectional view showing a main part process of a conventional electric motor assembling method.

FIG. 5 is a vertical sectional view of a conventional electric motor.

6A and 6B are a plan view and a side view of the washer holding plate used in FIG.

[Explanation of symbols]

 1 Stator Yoke 2 Fixed Field 3 Stator 4 Rotor 5 Rotating Shaft 8 First End Cover 9 Second End Cover 10 First Bearing 11 Second Bearing 14 Preload Spring 15 Washer Holding Plate

Claims (2)

[Claims] 1. A stator in which a stator field is attached to the inner circumference of a tubular stator yoke, a first end cover closing one end side of the stator yoke in the axial direction, and a stator yoke of the stator yoke. A second end cover that closes the other end, and a second bearing that is supported at one end by a first bearing fixed to the first end cover and that is inserted into a bearing holding recess provided in the second end cover. The rotating shaft whose other end is supported by the bearing, the rotor arranged inside the stator and attached to the rotating shaft, and the second bearing arranged in the bearing holding recess. In the electric motor having a preload spring for urging to the bearing side of No. 1, the outer diameter of the preload spring is larger than the inner diameter of the bearing holding recess of the second end cover. The preloaded spring motor, characterized in that it is arranged in a compressed state the outer diameter in the bearing holding recess of the second end cover. 2. The rotor, wherein the first bearing and the second bearing are attached to both ends of a rotary shaft holding the rotor, and then the first bearing is inserted into the recess of the first end cover. An assembly in which the rotating shaft holding the above is integrated with the first end cover, and the assembly is assembled with the first end cover facing downward and the rotating shaft in the vertical direction. The second end cover is placed on a workbench, and then the outer periphery of the second end cover is fitted to the other end of the stator yoke existing on the outer periphery of the first end cover, and the second bearing is attached to the first bearing side. In a method of assembling an electric motor, wherein the second bearing is inserted into the bearing holding recess of the second end cover via a preload spring biased to the front end of the second end cover, the preload spring having an outer diameter of A bearing holding recess of the end cover of the second end cover is used, and the second bearing is attached to the second bearing in a state where the preload spring is press-fitted and locked in the bearing holding recess of the second end cover. A method of assembling an electric motor, characterized by inserting the bearing into a bearing holding recess of an end cover.