JPH0539813A - Spindle motor - Google Patents

Abstract

PURPOSE:To provide a spindle motor with which grease inside a bearing is prevented from flowing outside a motor. CONSTITUTION:A thin plate-like cover 12 made of metal or hard resin is fixed to a shaft 1 in a slidable contact condition to an outer end face 9a of an outer ring 9 of a bearing 7 and to a recession 3a of a hub 3. Thus, grease 13 oozing from an installation part of a shield plate 8 is sealed.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a spindle motor.

[0002]

2. Description of the Related Art In a conventional spindle motor, in order to prevent grease in the bearing from flowing out of the motor,
Bearings with magnetic fluid seals and rubber seals were used.

[0003]

However, in the magnetic fluid seal device, the magnetic fluid may be scattered due to the high speed rotation of the motor, and the grease cannot be completely prevented from flowing out. The fluid sealing device has a problem of high cost.

Further, in a bearing with a rubber seal, since the width dimension (thickness) of the rubber seal portion is large, the width dimension of the entire bearing is large, and it may not be possible to use it for a thin spindle motor. Further, in the labyrinth, there is a problem that grease leaks out of the motor while the hub is stationary.

Therefore, an object of the present invention is to provide a spindle motor that solves the above-mentioned conventional problems.

[0006]

In order to achieve the above object, the present invention has a thin plate-like cover which is slidably contactable with the outer end surface of a bearing having a shield plate.

[0007]

The outer end surface of the bearing is hermetically sealed to reliably prevent the grease oozing out from the mounting portion of the shield plate from flowing out of the motor even when the hub rotates at a high speed and stops.

Since a thin bearing can be used and the cover is extremely thin, the width dimension (thickness) can be made smaller (compared to the conventional bearing with a rubber seal).

[0009]

The present invention will be described in detail below with reference to the drawings showing the embodiments.

FIG. 1 is a sectional view showing an embodiment of a spindle motor showing the present invention. Reference numeral 1 is a bracket, and a fixed shaft 2 is erected on the bracket 1.

Reference numeral 3 is a hub on which the magnetic disks 4 are mounted, and an annular rotor magnet 5 is mounted on the inner peripheral surface thereof.

Further, a stator 6 is provided at the center of the shaft 2.
Are fixed, and the stator 6 faces the inner peripheral surface of the rotor magnet 5 with a minute predetermined distance.

Reference numerals 7 and 7 denote bearings, and the hub 3 is rotatably mounted on the shaft 2 via the bearings 7 and 7.
Be pivoted to.

The lower bearing 7 has an inner ring 11 fixed to the shaft 2 and an outer ring 9 fixed to the hub 3, as shown in FIG.

Further, the bearing 7 has an annular shield plate 8 having a substantially Z-shaped cross section, and the shield plate 8 has an outer ring 9
It is attached to and fixed by a snap ring 10.

The annular cover 12 is slidably contactable with the outer end surface 9a of the outer ring 9 of the bearing and the recess 3a of the hub 3.
Are fixed to the shaft 2.

However, the thin plate-shaped cover 12 made of a metal plate or a hard resin is used for the outer end surface 9 of the outer ring 9 of the bearing.
By sealing a, the grease 13 oozing out from the mounting portion 15 of the shield plate 8 is surely prevented from flowing out of the motor even when the hub 3 (outer ring 9) is rotating at a high speed and stopped.

Also, the upper bearing 7 shown in FIG.
The bearing 7 of FIG. 2 is mounted upside down on the shaft 2 and the hub 3, and the cover 12 is fixed to the shaft 2 in the same manner as described above to prevent the grease 13 in the bearing 7 from flowing out of the motor.

As shown in FIG. 2, since the cover 12 is extremely thin and the bearing 7 can be thin, the width A can be made thinner than that of a conventional bearing with a rubber seal, which is very small. Suitable for (thin) motors.

As described above, even when the hub 3 (outer ring 9) is rotating at a high speed or stopped, the grease 13, 13 in the bearings 7, 7 on the upper and lower sides can be surely prevented from flowing out, so that the magnetic disk can be read and written. It is possible to stabilize and improve the quality without adversely affecting the operation such as malfunction.

Next, as shown in FIG. 3, the shaft 2 is integrally formed with the hub 3, and the shaft 2 is pivotally attached to the bracket 1 via the bearings 7 to rotate the hub 3 by a spindle. Even in the case of a motor,
It is possible to prevent the grease 13 in the bearing 7 from flowing out of the motor.

As shown in FIG. 4, the lower bearing 7 having the shield plate 8 fixed by the retaining ring 10 has an inner ring 11
Is fixed to the shaft 2, and the bracket 1 is fixed to the outer ring 9.

Thus, the outer end surface of the inner ring 11 of the bearing 7
An annular cover 12 is attached to the bracket 1 so that it can be slidably contacted with 11a.
Fixed to the concave portion 1a of the outer end surface 11a of the inner ring 11 of the bearing.
Is sealed to securely prevent the grease 13 in the bearing 7 from flowing out of the motor even when the shaft 2 (inner ring 11) rotates at high speed or stops.

As in the previous embodiment, the cover 12 is extremely thin and the bearing 7 can be thin, so that the width A can be made thinner than the conventional bearing with a rubber seal.

Next, as in the comparative example shown in FIG.
The shield plate 28 and the outer ring 29 can be fixed to the shield plate 28 by fixing them around the rubber 14 without using snap rings or caulking.
There is a gap with the mounting part 15 of (because the rubber 14 is in close contact)
Even when the bearing outer ring 29 rotates, the mounting part
It is possible to prevent the grease 13 from bleeding out from the 15, and it is possible to have the same performance as a bearing with a rubber seal.
Further, by providing the step portion 30 on the inner ring 31 and disposing the inner peripheral edge of the shield plate 28 close to the step portion 30, the sealing performance can be improved as compared with the conventional shield plate bearing. I can.

Further, since the bearing shown in FIG. 5 can be thin, it is suitable for a thin spindle motor. Moreover, since the shield plate 28 is not fixed by a retaining ring or caulking, the outer ring 29 can be fixed to the outer ring 29 when fixed. The deformation given can be reduced.

[0027]

Since the present invention is constructed as described above, it has the following great effects.

The cover 12 seals the outer end surface of the bearing 7 to ensure that the grease 13 oozing out from the mounting portion 15 of the shield plate 8 flows out of the motor even when the hub 3 rotates at a high speed and stops. Can be prevented.

Therefore, the grease 13 is prevented from leaking to the outside of the motor, so that the reading and writing of the magnetic disk will not be adversely affected by malfunction and the quality can be stabilized and improved.

The total width A of the cover 12 and the bearing 7 can be made thinner than the conventional bearing with a rubber seal, which is suitable for an ultra-small (thin) motor.

[Brief description of drawings]

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

FIG. 2 is an enlarged cross-sectional view of a main part of the spindle motor shown in FIG.

FIG. 3 is a sectional front view of another embodiment of the spindle motor of the present invention.

FIG. 4 is an enlarged cross-sectional view of a main part of the spindle motor of FIG.

FIG. 5 is a cross-sectional view showing a comparative example.

[Explanation of symbols]

 7 Bearing 8 Shield plate 12 Cover

Claims (1)

[Claims] 1. A spindle motor comprising a bearing 7 having a shield plate 8 and a thin plate-like cover 12 slidably attached to an outer end surface of the bearing 7.