JPH0614490A - Spindle motor - Google Patents

Abstract

PURPOSE:To provide a thin-type spindle motor very much suitable for a hard disc drive which has no leakage of grease and no generation of dust by incorporating no sealing mechanism into both end faces of each ball bearing and by fastening on an inner face of a bearing housing a disc-type sealing mechanism which has the same shielding effect as the sealing mechanism of the ball bearings. CONSTITUTION:In a spindle motor which has a bearing housing 4, ball bearings 1, 2, an outer ring of which is fastened to an inner face of the bearing housing, and a rotary shaft to which an inner ring of the ball bearings is fastened, no sealing mechanism is incorporated into both end faces of each ball bearing and a disc-type sealing mechanism 10 which shields one end of the ball bearings is installed with a little space formed between the rotary shaft and the sealing mechanism 10. At the same time, the disc-type sealing mechanism 10 is fastened to an inner face of the bearing housing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spindle motor, and particularly for a hard disk drive capable of suppressing leakage and dust generation of grease to maintain cleanliness in the hard disk drive and realizing an ultra-thin structure. Of the spindle motor.

[0002]

2. Description of the Related Art A conventional spindle motor for a hard disk drive will be described with reference to the drawings. FIG. 5 is a sectional view of a conventional spindle motor, and FIG. 6 is an enlarged sectional view of a bearing housing portion in which the ball bearing of FIG. 5 is mounted.

Referring to FIGS. 5 and 6, a conventional spindle motor has a stator including an iron core around which a winding is wound and a bearing housing 53 for fixing outer rings of ball bearings 51 and 52 at their inner circumferences. Ball bearings 51, 5
The second inner ring is rotatably supported by a fixed rotating shaft 54 and also has a rotor having a permanent magnet fixed to a back yoke. Ball bearings 51, 52
The seal mechanisms 51a and 52a are provided on at least one end surface of the machine to prevent grease from flowing out and generating dust.

7A and 7B are sectional views comparing the heights b and c of a ball bearing with a built-in seal mechanism and a ball bearing without a seal mechanism. Sealing mechanism 51 on one end face
The ball bearings 51 and 52 provided with a and 52a have the sealing mechanism 51a and
Since the groove portions for mounting 52a are required on both end surfaces, the ball bearings 61 and 62 having no seal mechanism are thinner by twice the depth a of the groove portions on one end surface.

[0005]

SUMMARY OF THE INVENTION The present invention has been proposed in view of the above problems of the prior art. As a ball bearing, a seal mechanism is not built in each end surface of the ball bearing, and a seal mechanism for the ball bearing is used. By providing a disk-shaped sealing mechanism with the same shielding effect to the inner circumference of the bearing housing, the objective is to provide a thin spindle motor that is suitable for hard disk drives that suppresses grease leakage and dust generation. To do.

[0006]

Means for Solving the Problems As a result of intensive research and development and trial production, the inventors of the present invention have achieved the above-mentioned object, and as a result, a bearing housing and a two-stage stack in which an outer ring is fixed to the inner circumference of the bearing housing In a spindle motor having a ball bearing arranged in the above and a rotary shaft to which an inner ring of the ball bearing is fixed, the two-tiered ball bearing does not have a seal mechanism built in each end surface, The first disk-shaped sealing mechanism that shields one end of the bearing is arranged with a slight gap between the first circular seal mechanism and the rotating shaft, and the second circle that shields the other end of the ball bearing. The plate-shaped sealing mechanism has a structure for sealing the ball bearing, and the first and second disc-shaped sealing mechanisms are fixed to the inner circumference of the bearing housing. Ndorumota is, has been led to completion of the present invention found that it is suitable for the purpose of the present invention.

[0007]

According to the present invention, the use of the ball bearings without the seal mechanism on both end surfaces makes it possible to reduce the thickness, and the necessary disc-shaped seal mechanism is provided at a place other than the ball bearing. Therefore, it is possible to provide a highly reliable spindle motor that is resistant to grease outflow and dust generation.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a spindle motor to which the present invention is applied will be described below with reference to the drawings. Needless to say, the present invention is not limited to this embodiment. Figure 1
FIG. 4 is a sectional view of an embodiment of the spindle motor of the present invention. FIG. 2 is an enlarged sectional view of a bearing housing portion in which the ball bearing of FIG. 1 is mounted.

1 and 2, the spindle motor of the present invention is a stator comprising an iron core 3 around which windings are wound, and a bearing housing 4 for fixing outer rings of ball bearings 1 and 2 at their inner circumferences. 5 and a rotor 9 having a permanent magnet 8 fixed to a back yoke 7 while being rotatably supported by a rotary shaft 6 to which inner rings of ball bearings 1 and 2 are fixed. The rotor 9 also serves as a hub for clamping the hard disk.

The ball bearings 1 and 2 are arranged in two layers, and no seal mechanism is built in both end surfaces of the ball bearings 1 and 2. Ball bearings that do not have a built-in sealing mechanism are extremely thin compared to ball bearings that have a built-in sealing mechanism.

Moreover, the first disk-shaped seal mechanism 10 for shielding one end of the ball bearing 1 is arranged with a slight gap from the rotary shaft 6 and the other end of the ball bearing 2. The second disk-shaped sealing mechanism 11 that shields the portion is not provided with an opening so as to seal the ball bearings 1 and 2. In addition, the first and second disc-shaped sealing mechanisms 10 and 11 are provided in the bearing housing 4
It is fixed to the inner circumference of.

FIG. 3 is a sectional view showing an embodiment of a hard disk drive to which the present invention is applied. FIG. 4 shows FIG.
FIG. 3 is an enlarged cross-sectional view of a bearing housing part in which the ball bearing of FIG. The same parts as those in FIGS. 1 and 2 are designated by the same reference numerals and the description thereof will be omitted. The disk-shaped hard disk 21 is
It is screwed to the rotor (hub) 9 via a clamper 24. When a predetermined current is applied to the winding wound around the iron core 3 of the stator 5, it acts on the permanent magnet 8 of the rotor 9 and the hard disk 21 rotates together with the rotor 9.

Heads 22 and 23 for reading signals and performing the following are arranged on both sides of the hard disk 21,
When the hard disk 21 is stopped, it is in contact with the hard disk 21, but when it is rotating, it floats a very small distance due to the pressure of air. Cleanliness within the hard disk drive must be maintained to compensate for this levitation.

[0014]

As is apparent from the above description, the spindle motor of the present invention uses a thin ball bearing as the ball bearing, which does not have a seal mechanism built in at both end surfaces thereof, and which is arranged in the circumferential direction of the rotary shaft. A disc-shaped sealing mechanism is provided with a slight gap between the rotary shaft and the rotary shaft, and the disc-shaped sealing mechanism is fixed to the inner circumference of the bearing housing other than the ball bearings so that the ultra-thin spindle motor Can be realized as a mold. Of course, since the cleanliness of the hard disk drive is maintained, it is possible to suppress the outflow and dust generation of grease.

[Brief description of drawings]

FIG. 1 is a sectional view of an embodiment of a spindle motor of the present invention.

2 is an enlarged cross-sectional view of a bearing housing part in which the ball bearing of FIG. 1 is mounted.

FIG. 3 is a sectional view of an embodiment of a hard disk drive to which the present invention is applied.

4 is an enlarged cross-sectional view of a bearing housing part in which the ball bearing of FIG. 3 is mounted. It

FIG. 5 is a sectional view of a conventional spindle motor.

6 is an enlarged cross-sectional view of a bearing housing part in which the ball bearing of FIG. 5 is mounted.

FIG. 7 is a cross-sectional view comparing the heights b and c of a ball bearing with a built-in seal mechanism and a ball bearing without a built-in seal mechanism. A shows a ball bearing with a built-in seal mechanism, and B shows a ball bearing without a built-in seal mechanism. .

[Explanation of symbols]

 1, 2 Ball bearing 3 Iron core 4 Bearing housing 5 Stator 6 Rotating shaft 7 Back yoke 8 Permanent magnet 9 Rotor (hub) 10, 11 Disc-shaped sealing mechanism 21 Hard disk 22, 23 Head 24 Clamper 51, 52 Ball bearing 51a , 52a One end face seal mechanism 53 Bearing housing 54 Rotating shaft 61, 62 Ball bearing without a built-in seal mechanism

Claims (3)

[Claims] 1. A spindle motor comprising a bearing housing, a ball bearing having an outer ring fixed to an inner circumference of the bearing housing, and a rotary shaft having an inner ring fixed to the ball bearing. The disk-shaped seal mechanism, which does not have a seal mechanism built in at both end faces thereof and shields one end of the ball bearing, is arranged with a slight gap provided between the rotary shaft and the rotary shaft. A spindle motor characterized by being fixed to the inner circumference of a housing. 2. The spindle motor according to claim 1, wherein the ball bearings that do not include the seal mechanism are arranged in a plurality of stacked layers. 3. A spindle motor comprising a bearing housing, ball bearings arranged in a two-tiered manner in which an outer ring is fixed to the inner periphery of the bearing housing, and a rotary shaft to which the inner ring of the ball bearing is fixed. The two-stage ball bearing does not have a seal mechanism built in at each end face, and the first disk-shaped seal mechanism that shields one end of the ball bearing has a slight gap between the rotary shaft and the rotary shaft. A second disk-shaped sealing mechanism, which is provided with a gap and shields the other end of the ball bearing, has a structure for sealing the ball bearing,
The first and second disc-shaped sealing mechanisms are fixed to the inner periphery of the bearing housing.