JP2001304254A - Pre-loading member for radial ball bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pre-loading member for a radial ball bearing scarcely deteriorated by heat, miniaturizing the size, and improving yield. SOLUTION: A wave ring 11 as a pre-loading member for the radial ball bearing 10 is so formed that a metal wire rod is bent annually in the length approximately same as the circumferential length of a bearing outer ring 10a and formed into a wave shape circumferentially.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a preload applying member for a radial ball bearing.

[0002]

2. Description of the Related Art As shown in FIG. 4, a rotating shaft 22 of a motor 21 is, for example, a bearing holding portion 23 of a motor housing 23.
a and 23b are rotatably supported by a pair of radial ball bearings 24 and 25.

[0003] Such radial ball bearings 24, 25 are
There is a gap between the inner and outer rings 24a, 24b, 25a, 25b and the steel balls 24c, 25c.
The rotation shaft 22 supported by the rotation shafts 4 and 25 rattles in the thrust direction due to a load change during rotation. This rattling is a factor of noise generation, and the inner and outer wheels 24a,
24b, 25a, 25b and steel balls 24c, 25
This is one factor that shortens the life of the bearings 24 and 25 by accelerating damage to the bearings c.

For this reason, as shown in FIG. 5, the motor 21 has one bearing 25 fitted in the bearing holding portion 23b so as to be movable in the thrust direction.
An annular wave washer 26 made of metal is interposed between the bearing 5a and the bearing holding portion 23b. The wave washer 26 applies a preload to the outer race 25a in one direction in the thrust direction, thereby preventing the above-described rattling in the thrust direction.

[0005] In addition to the wave washer 26, it is conceivable to use a rubber damper 27 as shown in FIG. 7 or a metal compression spring 28 as shown in FIG. However,
The rubber damper 27 is weak to heat and easily deteriorates. Compression spring 28
Is hard to be deteriorated by heat.
Although it is more excellent, since it is a member that is long in the direction of expansion and contraction, the overall length of the motor 21 in the thrust direction becomes long, and there is a problem that the motor 21 becomes large.

However, the wave washer 26
Is hardly deteriorated by heat and is plate-shaped, so that the total length of the motor 21 in the thrust direction can be shortened.
Can be reduced in size.

[0007]

By the way, the above-mentioned wave washer 26 is formed by punching a band-shaped hoop material 29 as shown in FIG. 6A into an annular shape and punching the intermediate member 30 as shown in FIG. 6B. Is formed so as to be circumferentially wavy as shown in FIG. 6 (c).

Accordingly, the shape of the intermediate member 30
A large amount of blank space remains in the hoop material 29 punched with 0, and the material yield is poor. Therefore, there is a problem in that the cost of the wave washer 26 and, consequently, the cost of the motor 21 increase.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a preload applying member for a radial ball bearing which can reduce deterioration due to heat, reduce the size, and improve the yield. Is to provide.

[0010]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, an invention according to claim 1 is provided between a bearing holding portion and a bearing outer ring movably fitted to the bearing holding portion. ,
In a preload applying member of a radial ball bearing for applying a preload to the bearing outer ring in one of the thrust directions and preventing rattling in the thrust direction of the rotating shaft, a metal wire is provided with a length in a circumferential direction of the outer ring. It was bent in an annular shape with substantially the same length, and formed in a wavy shape in the circumferential direction.

According to the invention described in claim 2, the cross section of the wire is substantially circular. The invention according to claim 3 has a polygonal annular shape. According to a fourth aspect of the present invention, the dimensions are set so as to be pressed into the bearing holding portion.

(Operation) According to the first aspect of the present invention,
The preload applying member of the radial ball bearing is formed by bending a metal wire into a ring having a length substantially similar to the length in the circumferential direction of the bearing outer ring, and forming a wavy shape in the circumferential direction. Therefore, since it is made of metal, deterioration due to heat is small, and the length in the thrust direction can be small. Moreover, in forming the preload applying member, the preload applying member of the present invention does not leave a blank space unlike the conventional case, so that the yield is greatly improved.

According to the second aspect of the present invention, since the cross section of the wire is substantially circular, the contact position with the bearing outer ring does not significantly shift even if the diameter is increased to secure a preload. Therefore, when such a preload applying member is used for a radial ball bearing provided with a seal member for closing the opening between the inner and outer rings, it is possible to prevent the preload applying member from interfering with the seal member, and to prevent the seal member from being used. Damage can be prevented.

According to the third aspect of the present invention, since the polygonal ring is formed, the springback (returning in the opposite direction to the bending direction at the time of bending) is smaller than that formed by bending into an annular shape. easy.

According to the fourth aspect of the present invention, since the dimensions are set so as to be press-fitted into the bearing holding portion, the preload applying member does not fall even if the opening of the mounted bearing holding portion is directed downward. . Therefore, the degree of freedom of attachment is improved.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a DC motor 1 of the present embodiment. The DC motor 1 has a cylindrical yoke housing 2 with a bottom, and a plurality of magnets 3 are fixed to an inner surface of the yoke housing. In the center of the bottom (upper side in FIG. 1) of the yoke housing 2, a bearing holding portion 2a extending substantially in a cylindrical shape with a bottom is provided, and a radial ball bearing 4 is press-fitted into the bearing holding portion 2a. .
An armature 5 is housed inside the magnet 3, and a rotation shaft 6 of the armature 5 has a base end portion of a radial ball bearing 4.
Are supported rotatably. The radial ball bearing 4 includes an outer ring 4a, an inner ring 4b, a steel ball 4c,
A pair of seal members 4d and the like are provided. The outer ring 4a is press-fitted into the bearing holding portion 2a, and the inner ring 4b is press-fitted into the rotating shaft 6. The seal member 4d is fixed to the outer ring 4a, and is provided for closing an opening between the inner and outer rings 4a and 4b to prevent foreign matter from entering between the inner and outer rings 4a and 4b.

An end housing 7 is mounted on an opening (the lower side in FIG. 1) of the yoke housing 2. The end housing 7 is integrally formed with a brush holding portion 7a for holding a brush 9 that slides on the commutator 8 of the armature 5. At the center of the end housing 7, there is provided a bearing holding portion 7b extending substantially in a cylindrical shape with a bottom. A radial ball bearing 10 is fitted into the bearing holding portion 7b so as to be movable in the thrust direction. ing.
The radial ball bearing 10 rotatably supports the rotary shaft 6, and the rotary shaft 6 is inserted into an insertion hole 7c provided at the center of the bottom of the bearing holding portion 7b. Note that this radial ball bearing 10
Is provided with an outer ring 10a, an inner ring 10b, a steel ball 10c, a pair of seal members 10d, and the like, like the bearing 4, and the outer ring 10a is fitted to the bearing holding portion 7b so as to be movable in the thrust direction. Are press-fitted into the rotating shaft 6. The sealing member 10d is fixed to the outer ring 10a,
By closing the opening between the inner and outer rings 10a, 10b, the inner and outer rings 10a,
It is provided to prevent foreign matter from entering between the spaces 10b.

As shown in FIG. 2, a wave ring 11 as a preload holding member is inserted between the bottom of the bearing holding portion 7b and the surface of the bearing 10 facing the outer ring 10a. In the present embodiment, the wave ring 11 is formed in a dodecagonal (polygonal) ring shape so that the length in the circumferential direction is substantially the same as that of the outer ring 10a, and is further formed in a circumferential wave shape. The outer diameter of the wave ring 11 is
In the present embodiment, it is set to be the same as the inner diameter of the bearing holding portion 7b.

In the present embodiment, the wave ring 11 is formed such that a wire 12 composed of a single piano wire having a circular cross section as shown in FIG. 3A has substantially the same length as the circumferential length of the outer ring 10a. To a predetermined length, and the cut wire 1
2 is formed into a dodecagonally shaped intermediate member 13 as shown in FIG.
It is formed by pressing so as to be wavy in the circumferential direction as shown in FIG.

The wave ring 11 has an elastic force in the thrust direction, and applies a preload to the outer ring 10a (the bearing 10) in one of the thrust directions by the elastic force. Shaking in the direction is prevented.

As described above, according to the present embodiment,
It has the following effects. (1) The wave ring 11 as a preload applying member is formed by bending a metal wire 12 into a polygonal ring with a length substantially equal to the length in the circumferential direction of the outer ring 10a of the bearing 10 and forming a wavy shape in the circumferential direction. It comes from things. Therefore, the wave ring 11
Since it is made of metal, it is hardly deteriorated by heat, and its length in the thrust direction can be small. Moreover, when forming the wave ring 11, the conventional wave washer 26
As described above, no blank space remains, so that the yield can be greatly improved. As a result, the wave ring 11,
Consequently, the cost of the motor 1 can be reduced.

(2) Since the wave ring 11 has a polygonal ring shape, springback (returning in the direction opposite to the bending direction at the time of bending) is smaller than bending in an annular shape, and the wave ring 11 is easy to form.

(3) Since the cross section of the wave ring 11 is circular, the contact position of the bearing 10 with the outer ring 10a does not significantly shift even if the diameter is increased to secure a preload. Here, the conventional wave washer 26 shown in FIG.
In order to secure a preload, the plate thickness and width of the washer 26 must be increased. However, if the width of the washer 26 is increased, the washer 26 may interfere with the seal member 25d provided on the bearing 25 due to a bending accuracy error or the like. Then, the washer 26 presses the seal member 25d toward the inner ring 25b, and the seal member 25d
Is in sliding contact with the inner ring 25b that rotates with the rotating shaft 22. Therefore, the wave washer 26 is attached to the sealing member 25.
When used for the radial ball bearing 25 provided with d, the seal member 25d and the inner ring 25b may be damaged earlier, and the life of the bearing 25 may be shortened.

On the other hand, even if the diameter of the wave ring 11 of this embodiment is increased in order to secure a preload, the contact position of the bearing 10 with the outer ring 10a is not largely shifted. Interference can be prevented, and damage to the seal member 10a and the like can be prevented.

The embodiment of the present invention may be modified as follows. In the above embodiment, the wave ring 11 is formed in a dodecagonal ring, but may be formed in another polygonal ring. Further, the wave ring 11 may be annular.

In the above embodiment, the wave ring 11
Although the cross-section of the wire rod 12 is circular, the cross-section may be a substantially circular shape such as an elliptical shape. In addition, when the wire does not interfere with the seal member even when the wire is thickened, or when used for a radial ball bearing without a seal member, a wave having a cross section other than a substantially circular shape, for example, a wire having a rectangular cross section is used. A ring may be formed. It may be.

In the above embodiment, the wave ring 11
Is set to be the same as the inner diameter of the bearing holding portion 7b.
Dimensions such as wave ring 1
One gap may be enlarged. In this way, even if the opening of the bearing holding portion 7b to be mounted is directed downward, the wave ring 11 does not fall. Therefore, the degree of freedom of attachment is improved.

In the above embodiment, the wave ring 11
Is used as one piano wire, but the wave ring 11 may be formed using a wire as a wire.

In the above embodiment, the wave ring 11
Is used for the bearing device of the motor 1, but may be used for other bearing devices. The technical ideas other than the claims that can be grasped from the above embodiments will be described below together with their effects.

(A) A motor comprising the radial ball bearing preload applying member according to any one of claims 1 to 4. By doing so, it is possible to reduce the size and cost of the motor.

[0031]

As described in detail above, according to the present invention,
It is possible to provide a radial ball bearing preload applying member that is less likely to deteriorate due to heat, can be reduced in size, and can improve the yield.

[Brief description of the drawings]

FIG. 1 is a sectional view of a DC motor according to an embodiment.

FIG. 2 is a sectional view of a bearing portion of the motor.

FIG. 3 is a diagram for explaining a manufacturing process of a wave ring.

FIG. 4 is a sectional view of a conventional DC motor.

FIG. 5 is a sectional view of a bearing portion of the motor.

FIG. 6 is a diagram for explaining a manufacturing process of the wave washer.

FIG. 7 is a sectional view of a bearing portion of a conventional motor.

FIG. 8 is a sectional view of a bearing portion of a conventional motor.

[Explanation of symbols]

7b: bearing holder, 10: radial ball bearing, 10a: outer ring, 11: wave ring as a preload applying member.

Continued on the front page (72) Inventor Yoshimasa Tomita 390 Umeda, Kosai-shi, Shizuoka Prefecture Asmo Corporation (72) Inventor Sumika Kamogawa 390 Umeda, Kosai-shi, Shizuoka Prefecture Asmo Corporation (72) Inventor Tetsuro Niimura Shizuoka Shizuoka 390 Umeda, Kosai Prefecture, Japan Asmo Co., Ltd. F-term (reference)

Claims (4)

[Claims] 1. A preload is interposed between a bearing holding portion and a bearing outer ring movably fitted to the bearing holding portion, and a preload is applied to the bearing outer ring in one of the thrust directions. In a preload applying member of a radial ball bearing for preventing rattling, a metal wire rod is bent annularly in a length substantially similar to a length in a circumferential direction of the outer ring, and formed in a wavy shape in a circumferential direction. Characteristic preload applying member for radial ball bearings. 2. The preload applying member for a radial ball bearing according to claim 1, wherein a cross section of the wire is substantially circular. 3. The preload applying member for a radial ball bearing according to claim 1, wherein the preload applying member is a polygonal ring. 4. The apparatus according to claim 1, wherein dimensions are set so as to be press-fitted into said bearing holding portion.
A preload applying member for a radial ball bearing according to item 8.