JP2002054639A - Rolling bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent noise and rotation accuracy deterioration of a motor by improving impact resistance of a bearing. SOLUTION: In a ball bearing 20 having a number of balls B put between an outer ring 29 and an inner ring 28 along a circumference direction, a thickness (a) in a diameter direction of a part contacting balls B of the outer ring 29 is thinner than a thickness (b) in a diameter direction of a part contacting balls B of the inner ring 28.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rolling bearing in which a number of rolling elements are interposed between an outer ring and an inner ring along a circumferential direction, for example, a motor for a video tape recorder (VTR), a laser beam printer ( The present invention relates to a rolling bearing incorporated in a rotation support portion of an LBP) motor, a magnetic disk device motor, or the like, or a swing support portion of a swing arm of a magnetic disk device.

[0002]

2. Description of the Related Art FIG. 5 shows a state in which a ball bearing (rolling bearing) is incorporated in a rotation supporting portion of a motor of a magnetic disk drive. In the figure, reference numeral 1 denotes a rotating shaft, 2 denotes a hub concentrically fixed to the upper end of the rotating shaft 1, 3 denotes a rotor (magnet portion) attached to an inner peripheral portion of the hub 2, and an outer peripheral portion of the hub 2 A disk (not shown) is mounted.

[0003] The rotating shaft 1 is rotatably supported by a sleeve 5 provided integrally with the motor base 4 via two ball bearings 6. A stator 7 is attached to the outer periphery of the sleeve 5 so as to face the rotor 3. Two ball bearings 6
Are numerous balls (rolling elements) between the inner ring 8 and the outer ring 9
B is interposed along the circumferential direction, and is spaced apart from each other in the axial direction of the rotating shaft 1, and a spacer 10 is interposed between each outer ring 9. Shield plates 11 are arranged at both axial ends of the ball bearing 6, thereby preventing dust and the like from entering the bearing from the outside and preventing grease or the like filled in the bearing. Lubricants are prevented from scattering to the outside. The outer peripheral edge of the shield plate 11 is locked on the inner diameter surface of the outer ring 9, and the inner peripheral edge is arranged close to the outer diameter surface of the inner ring 8.

[0004] Rotating members such as the rotating shaft 1 and the hub 2 are radially supported via two ball bearings 6 and rotatably supported around a stator 7. The rotating member rotates integrally.

[0005]

As described above, in the ball bearing 6 incorporated in a magnetic disk drive or the like as described above, the ball B is disposed at the center of the inner and outer rings 8, 9, and therefore, the ball B of the inner ring 8 is provided. Of the outer ring 9 and the radial thickness of the portion where
In general, the thickness in the radial direction of the portion where the contact is made is equal.

However, in such a ball bearing in which the inner and outer rings 8 and 9 have the same thickness, when a shock is applied to the motor by, for example, dropping the magnetic disk device or the like in the direction A, the rotating member of the motor may be damaged. A large acceleration acts in a short time, and forces Ai and A0 act on the inner ring 8 and the outer ring 9 in the contact angle direction through the rotating member. When this force (load) exceeds the elastic range of the bearing material, plastic deformation occurs in the bearing race or the ball, causing problems such as deterioration of the sound and rotation accuracy of the motor.

SUMMARY OF THE INVENTION The present invention has been made to solve such inconveniences, and an object of the present invention is to provide a rolling bearing capable of suppressing deterioration of sound and rotational accuracy even when a shock is applied to a motor. And

[0008]

In order to achieve the above object, a rolling bearing according to the present invention is a rolling bearing in which a number of rolling elements are interposed between an outer ring and an inner ring along a circumferential direction. A radial thickness of a portion of the outer ring contacting with the rolling element is made smaller than a radial thickness of a portion of the inner ring contacting with the rolling element.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view of an essential part for explaining a ball bearing which is an example of an embodiment of the present invention, and FIGS.
FIG. 4 is a cross-sectional view of a principal part for describing a ball bearing according to another embodiment of the present invention. In each of the embodiments, a ball bearing is taken as an example of a rolling bearing, and a case where the ball bearing is incorporated in a rotation support portion of a motor of a magnetic disk drive is taken as in the conventional example (FIG. 5). Therefore, FIG.
Only the parts different from the above are shown, and the illustration and description of the overlapping parts are omitted.

Referring to FIG. 1, this ball bearing 20 has a large number of balls (rolling elements) B interposed between an inner ring 28 and an outer ring 29 along a circumferential direction. It is arranged at two places with the sleeve 5 apart from each other in the axial direction. In the drawing, reference numeral 30 denotes a locking groove formed on the inner diameter surface of both ends of the outer ring 29 and locking the outer peripheral edge of the shield plate 11.

In this embodiment, the radial thickness a of the portion of the outer ring 29 which contacts the ball B is determined by the ball B of the inner ring 28.
Is thinner than the radial thickness b of the portion in contact with. Thus, when the magnetic disk device falls and an impact force is applied to the motor, the outer ring 29 expands radially outward due to the contact angle direction force A0 acting on the outer ring 29 through the rotating member. And the outer ring 29 is greatly expanded radially outward, so that the dispersion of the force A0 is suppressed.

Therefore, when the same impact force is applied to the motor of the magnetic disk drive, the force acting on the inner and outer rings 28 and 29 and the ball B is reduced as compared with the conventional case, and as a result, the impact resistance of the bearing is improved. Thus, it is possible to prevent the sound and rotation accuracy of the motor from deteriorating. In the above embodiment, the thickness of the outer ring 29 in the radial direction
Although the case where the radial thickness a of the contacting portion is reduced is taken as an example, instead of this, as shown in FIGS. May be made thinner.

In this case, in addition to the above-described operation and effect, the outer ring outer diameter surface of the portion of the outer ring 29 where the ball B comes into contact is separated from the sleeve 5 inner diameter surface, so that the deformation of the outer ring bonding portion at the contact angle position is prevented. can do. In this case, the outer ring 29
The fitting state between the sleeve 5 and the sleeve 5 may be either bonding alone or press-fitting + bonding.

[0014]

As is apparent from the above description, according to the present invention, when an impact force is applied to a motor of a magnetic disk drive or the like, the forces acting on the inner and outer races and the rolling elements are reduced as compared with the prior art. Therefore, it is possible to obtain an effect that the impact resistance of the bearing is improved and the sound and rotation accuracy of the motor can be prevented from deteriorating.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a principal part for explaining a ball bearing which is an example of an embodiment of the present invention.

FIG. 2 is an explanatory cross-sectional view of a principal part for describing a ball bearing according to another embodiment of the present invention.

FIG. 3 is a cross-sectional view of a principal part for describing a ball bearing according to another embodiment of the present invention.

FIG. 4 is an explanatory main part sectional view for explaining a ball bearing according to another embodiment of the present invention.

FIG. 5 is a cross-sectional view showing a state where a conventional ball bearing is incorporated in a rotation support portion of a motor of a magnetic disk drive.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Rotating shaft 5 ... Sleeve 10 ... Spacer 20 ... Ball bearing (rolling bearing) 28 ... Inner ring 29 ... Outer ring B ... Ball (rolling element) a ... Radial wall thickness of the portion of the outer ring 29 where the ball B comes into contact b … The radial thickness of the portion of the inner ring 28 that contacts the ball B

Continued on the front page (72) Inventor Takayuki Miyagawa 1-5-50 Kugenuma Shinmei, Fujisawa-shi, Kanagawa Nippon Seiko Co., Ltd. (72) Inventor Nobuhiko Nishimura 1-150 Kugenuma Shinmei, Fujisawa-shi, Kanagawa Nippon Seiko Shares In-house F term (reference) 3J101 AA02 AA42 AA54 AA62 BA53 BA54 BA56 FA31 GA24 GA53 5H605 BB05 BB19 CC04 EB10 EB28 GG04

Claims (1)

[Claims] In a rolling bearing in which a number of rolling elements are interposed between an outer ring and an inner ring along a circumferential direction, a radial thickness of a portion where the rolling elements of the outer ring come into contact with each other is adjusted by the rolling element of the inner ring. A rolling bearing characterized in that it is thinner than a radial thickness of a contacting part.