JPH0591704A - Spindle motor - Google Patents

Abstract

PURPOSE:To provide a spindle motor which can be sealed without providing the sealing device using a magnetic fluid and whose cost can be reduced. CONSTITUTION:A member for giving pre-loads to bearings 8, 8 when assembling a spindle motor is provided on the shaft of the motor. As a labyrinth member 14 for performing a labyrinth action to a rotating hub 6, the member for giving pre-loads is used (is made to serve for a double purpose).

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 the conventional assembly of a spindle motor, after a bearing is fixed to a shaft and a hub in a state where a preload is applied to the bearing, an annular ring (between the hub and the shaft) near the bearing is provided. A magnetic fluid seal device was attached to the gap to prevent the grease in the bearing from flowing out of the motor.

As described above, the step of mounting the bearing by applying a preload and the step of mounting the magnetic fluid seal device are separate.

[0004]

However, when the magnetic fluid seal device is provided, there is a problem that the cost becomes high, and
It was not suitable for thin motors.

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

[0006]

In order to achieve the above object, the present invention combines a member for applying a preload to a bearing during assembly and a labyrinth member for performing a labyrinth action on a rotating hub. And is fixed to the shaft 1.

A labyrinth groove forming unit is formed by a pair of an annular first member and an annular second member having a substantially L-shaped or T-shaped cross section, and a plurality of these labyrinth groove forming units are stacked. , Is provided in the annular gap between the shaft and the hub.

[0008]

With the labyrinth member, the grease or the like flowing out from the bearing due to the rotation of the hub can be sealed without using the magnetic fluid sealing device to prevent the grease or the like from scattering or flowing out to the outside of the motor. ..

Further, since the labyrinth member which performs a labyrinth action on the rotating hub can be used as a pressing member for applying a preload to the bearing, the labyrinth member is attached to the shaft when the step of applying the preload to the bearing is completed. The process is complete.

Further, in a case where a plurality of labyrinth groove forming units are provided in a stacked shape in the annular gap portion between the shaft and the hub, the gap formed by the first member and the second member (that is, the labyrinth groove) is It becomes a meandering shape with a minute predetermined interval. Therefore, the gap distance from the bearing portion to the outside of the motor is substantially increased, the sealing performance is improved, and the grease and the like can be reliably prevented from flowing out to the outside of the motor.

[0011]

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 shaft, and the shaft 1 has a connecting portion 2 integrally formed at a lower end portion thereof.

Reference numeral 3 denotes a stator fixedly attached to the outer periphery of the connecting portion 2. The stator 3 comprises a stator core 4 and a stator coil 5 wound around the stator core 4.

Reference numeral 6 denotes a hub on which a magnetic disk or the like is mounted, and an annular rotor magnet 7 is mounted on the inner peripheral surface of the hub.

The stator 3 faces the inner peripheral surface of the rotor magnet 7 with a small predetermined distance.

Reference numerals 8 and 8 denote bearings, and the hub 6 is rotatably attached to the shaft 1 via the bearings 8 and 8.

Specifically, as shown in FIG. 2, the bearings 8,
Inner rings 9a and 9b of 8 are fitted onto the shaft 1, and a hub 6 is fixed to the outer rings 10a and 10b.
A spacer 11 is interposed between the inner rings 9a and 9b of both bearings 8 and 8. The inner ring 9a on the upper side of the figure is loosely fitted onto the shaft 1.

A thin, annular labyrinth member 14 is fixed to the shaft 1 at the upper portion of the upper bearing 8 (annular gap 12 between the shaft 1 and the hub 6) in FIG. The labyrinth member 14 has a collar portion 13, and the collar portion 13 has a hub 6.
It faces the inner peripheral surface of the device with a minute predetermined distance. Moreover, the lower end surface (in the figure) of the labyrinth member 14 directly presses the upper inner ring 9a (in the figure).

Therefore, the bearings 8 and 8 are preloaded in the direction of arrow A to the upper inner ring 9a through the labyrinth member 14 in order to prevent rattling when the hub 6 rotates.

Reference numeral 16 is a pressing member such as a weight for applying a preload to the bearings 8 and 8 at the time of assembly. The pressing member 16 directly contacts the labyrinth member 14 described above, and through the labyrinth member 14, A force for preload is applied to the upper inner ring 9a (in the figure).

Next, a procedure for applying a preload during assembly will be described.

First, the spacers 11 are interposed between the bearings 8 and 8, and the upper and lower outer rings 10a and 10b are adhered and solidified on the inner peripheral surface of the hub 6.

After that, the upper and lower inner rings 9a and 9b shown in FIG. At this time, the upper and lower inner rings 9a,
An adhesive is applied to the inner peripheral surface of each 9b. Next, an adhesive is applied to the inner peripheral surface of the labyrinth member 14 so that the shaft 1
Then, a preload is applied in the direction A by the pressing member 16 to the (loose) upper inner ring 9a portion via the labyrinth member 14.

Then, until the adhesives applied to the labyrinth member 14 and the upper and lower inner rings 9a and 9b are solidified,
A state in which a preload is applied by the pressing member 16 is maintained.

At this time, since the upper and lower outer rings 10a and 10b are solidified, the upper inner ring 9a contacts at an obliquely upper portion of the upper spherical body 15a (upper left diagonally in the illustrated example), and the upper outer ring 10a makes an oblique lower portion of the upper spherical body 15a. (In the illustrated example, diagonally downward to the right), and the preload in the A direction is applied to the hub 6 via the upper sphere 15a as indicated by arrow E, and the lower inner ring 9b comes into contact at the diagonally lower portion of the lower sphere 15b.
The lower outer ring 10b contacts at an obliquely upper portion of the lower sphere 15b.

After the adhesive is solidified, if only the pressing member 16 is removed, the assembling work is completed. In this embodiment, the inner rings 9a and 9b of the bearings 8 and 8 and the shaft 1 are fixed to each other with an adhesive in order to ensure that the preload state is maintained. However, even if these adhesives are not applied, at least the pressing by the labyrinth member 14 and the adhesion with the shaft 1 are surely acceptable.

In this way, by applying the preload, both bearings 8 and 8 are, as shown in the drawing, the direction of the angle at which the upper sphere 15a and the upper and outer inner rings 9a and 10a come into contact with each other, and the lower sphere 15b and the lower inner and outer spheres. The directions of the angles at which the wheels 9b and 10b contact each other are opposite to each other, and the load direction lines B and C intersect the axis D at an angle.

The labyrinth member 14 seals grease or the like scattered or flowing out from the upper bearing 8 with the rotation of the hub 6 by a labyrinth action to prevent grease or the like from the annular gap portion 12 to the outside of the motor. It is possible to prevent outflow.

Then, as described above, the labyrinth member 14
Serves both as a labyrinth for the rotating hub 6 and as a member for applying a preload.

Therefore, unlike the conventional case, a magnetic fluid seal is not required to prevent the grease or the like from scattering and flowing out to the outside of the motor. Therefore, the step of fitting the magnetic fluid seal can be omitted, and at the same time in the step of applying preload. Since the labyrinth member 14 having a sealing action can be provided, the assembly time can be shortened and the cost can be reduced. Further, since the labyrinth member 14 is thin, it is suitable for an ultra-small (thin) motor.

Next, FIG. 3 shows a cross section of a main part of a spindle motor of another embodiment. In this motor, a plurality of (in the illustrated example, 2
The individual labyrinth groove forming units 20 ... Are interposed as a stack.

The labyrinth groove forming unit 20 is made of a plastic molded product or a metal, and has a pair of annular first members 21 and annular second members each having a substantially L-shaped or T-shaped cross section.
It is formed with 22. In FIG. 3, the first member 21
Is a substantially L-shaped cross section, and the second member 22 is a substantially T-shaped case.

Therefore, the upper portion of the bearing 23 pivotally mounted between the shaft 17 and the hub 18 (the annular gap portion between the shaft 17 and the hub 18).
19), the second member 22, 22 is attached to the shaft 17, and the hub 18
The first members 21 and 21 are fitted to the inner peripheral surface of each by press-fitting or adhesion or the like.

At this time, the first members 21, 21 and the second member 2
The gap formed by 2 and 22 (that is, the labyrinth groove) is in a meandering shape and has a communicating shape with a minute predetermined distance.

The units 20 and 20 seal the grease or the like flowing out from the bearing 23 with the rotation of the hub 18 by a labyrinth action to prevent the grease or the like from flowing out of the annular gap portion 19 to the outside of the motor. You can

Particularly, since the labyrinth groove has a meandering shape, the annular gap portion communicating from the bearing 23 to the outside of the motor is formed.
The void distance of 19 is substantially increased, which improves the sealing performance and reliably prevents scattering and outflow.

The present invention is not limited to the above-mentioned embodiment, and the design can be freely changed without departing from the gist of the present invention. In FIG. 3, the unit 20 can be laminated in two or more stages. It is also desirable to have unit 20 as follows.

For example, as shown in FIG. 4, the first member 21 and the second member 22 are vertically inverted with respect to FIG. 3, or are interposed, or, as shown in FIG. 5, the first member 21 and the second member 22. Each of the two members 22 has a substantially L-shaped cross section, or, as shown in FIG. 6, both the first member 21 and the second member 22 have a substantially T-shaped cross section.

3 to 6, the uppermost second member 22 may be pressed to apply a preload to the inner ring of the bearing 23. That is, it is also preferable that the second members 22 of the labyrinth groove forming units 20 shown in FIGS. 3 to 6 are also used as members for applying a preload to the bearing 23 during assembly.

[0040]

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

In the motor according to the first aspect, the magnetic fluid seal can be omitted, and the labyrinth member 14 having the sealing action can be provided at the same time in the step of applying the preload, so that the assembling time can be shortened and the cost can be reduced.

Since the labyrinth member 14 is thin, it is suitable for an ultra-small (thin) motor.

In the motor of claim 2, the units 20, 20
Can seal the grease or the like flowing out from the bearing 23 with the rotation of the hub 18 by the labyrinth action to prevent the grease or the like from flowing out of the annular gap portion 19 to the outside of the motor.

In particular, since the labyrinth groove has a meandering shape, the sealing performance is high and the outflow can be reliably prevented.

[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 cross-sectional view of essential parts of another embodiment of the spindle motor of the present invention.

FIG. 4 is a cross-sectional view of main parts showing a modified example of FIG.

FIG. 5 is a cross-sectional view of an essential part showing another modification.

FIG. 6 is a cross-sectional view of an essential part showing another modification.

[Explanation of symbols]

 6 hub 8 bearing 14 labyrinth member 17 shaft 18 hub 19 annular gap 21 first member 22 second member

Claims (2)

[Claims] 1. A member for applying a preload to the bearings 8, 8 during assembly and a labyrinth member 14 for performing a labyrinth action on the rotating hub 6 are also fixed to the shaft 1. Spindle motor. 2. A labyrinth groove forming unit 20 is formed by a pair of an annular first member 21 and an annular second member 22 having a substantially L-shaped or T-shaped cross section, and a plurality of the labyrinth groove forming units 20 are formed. A spindle motor in which the shaft 17 and the hub 18 are interposed in an annular gap portion 19 in a stacked state.