JP3124650B2 - Spindle motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spindle motor for rotating a recording disk.

[0002]

2. Description of the Related Art In general, there are a spindle motor of a fixed shaft type and a shaft rotation type. The fixed-shaft type includes a stationary shaft member, a hub rotatably supported on the shaft member via a bearing member, a rotor magnet mounted on the hub, and a facing magnet. It has a stator. In addition, the shaft rotation type
A stationary member, a hub rotatably disposed with respect to the stationary member, a rotating shaft member provided on the hub, a bearing member interposed between the rotating shaft member and the stationary member, and a mounting member mounted on the hub. And a stator disposed opposite to the rotor magnet.

[0003] In these spindle motors, a magnetic fluid sealing means is provided outside the bearing member in order to prevent impurities (for example, grease used in the bearing member) inside the motor from scattering outside. ing. The magnetic fluid sealing means includes an annular mounting member and a magnetic fluid holding means mounted on the mounting member. For example, the mounting member is mounted on a hub (or a stationary member), and the magnetic fluid holding means and the stationary shaft member are provided. (Or a rotating shaft member) is filled with a magnetic fluid.

[0004]

However, this kind of spindle motor has the following problems to be solved. That is, the attachment member of the magnetic fluid sealing means is usually attached to the hub (or the stationary member) using an adhesive, but when the fixation by the adhesive is insufficient (for example, the adhesive is not sufficiently applied), this attachment is performed. A small space is created between the member and the hub (or stationary member). On the other hand, grease used for bearing members generally tends to release oil when used for a long time. Therefore, when oil is released from the grease by use in a motor with an insufficiently fixed mounting member, the released oil flows to the outside through a minute space between the mounting member and the hub (or a stationary member), This causes a problem that the oil adheres to the surface of the recording disk.

An object of the present invention is to provide a spindle motor capable of reliably preventing oil released from grease from flowing out to the outside.

[0006]

In the spindle motor according to the present invention, oil absorbing means for absorbing free oil from grease filled in the bearing member is provided outside the bearing member.

[0007]

In the above spindle motor, since the oil absorbing means is provided outside the bearing member, when the oil released from the grease flows to the outside, the flowing oil is absorbed by the oil absorbing means. It does not flow out. Accordingly, the oil absorbing means reliably prevents the released oil from flowing out to the outside.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a spindle motor according to the present invention will be described below with reference to the accompanying drawings. In FIG. 1, the illustrated spindle motor includes a stationary shaft member 2 and a hub 4 that is rotatable relative to the stationary shaft member 2. A cup-shaped member 6 is fixed to the lower end of the shaft member 2, and the cup-shaped member 6 is attached to a lower frame (not shown) of the disk drive.

Bearing members 8 and 10 are provided at both ends of the shaft member 2.
The hub 4 is rotatably supported by the bearing members 8 and 10. The hub 4 includes a cylindrical hub body 12,
It has an end wall 14 provided at one end of the hub main body 12 and an annular holding member 16 attached to the other end of the hub main body 12. The end wall 14 is supported by one bearing member 8, The other end of the main body 12 is supported by the other bearing member 10 via the holding member 16.

A stator 18 is mounted on an intermediate portion of the shaft member 2 (a portion between the pair of bearing members 8 and 10).
The stator 18 includes a stator core 2 fixed to the shaft member 2.
0 and an armature coil 22 wound around the teeth of the stator core 20 as required. on the other hand,
An annular rotor magnet 2 is provided on the inner peripheral surface of the hub body 12.
4 is attached. The rotor magnet 24 faces the stator 18 and is located on the outside in the radial direction.

A flange 26 is provided on the outer peripheral surface of the open end of the hub body 12, and a recording disk (not shown) such as a magnetic disk is disposed on the upper surface of the flange 26 via a spacer in the vertical direction. Are placed at intervals.

Magnetic fluid sealing means 30 and 32 are provided outside the pair of bearing members 8 and 10. The magnetic fluid sealing means 30 and 32 have substantially the same configuration, one of which will be described below. Referring also to FIG. 2, the illustrated magnetic fluid sealing means 30 (32) includes an annular mounting member 34 and a magnetic fluid holding means 36 attached thereto. The magnetic fluid holding means 36 has an annular permanent shape. It comprises a magnet 38 and a pair of pole pieces 40 and 42 arranged on both sides of the permanent magnet 36. Further, the mounting member 34 has an inner flange 44 protruding inward in the radial direction, and the magnetic fluid holding means 36 is mounted so as to be mounted on the inner flange 44. Then, the inner peripheral surface of the mounting member 34 and the outer peripheral surface of the magnetic fluid holding means 36 are fixed with an adhesive.

The magnetic fluid sealing means 30 and 32 are mounted as follows. That is, the magnetic fluid sealing means 30
In the above, the mounting member 34 is positioned at a predetermined position by abutting the shoulder formed on the end wall 14 of the hub 4, and the outer peripheral surface of the mounting member 34 and the inner peripheral surface of the end wall 14 are bonded with an adhesive. Is fixed by In the other magnetic fluid sealing means 32, the mounting member 34 is positioned at a predetermined position by being brought into contact with a shoulder formed on the holding member 16, and the outer peripheral surface of the mounting member 34 and the inside of the holding member 16. The peripheral surface is fixed with an adhesive. The space between the magnetic fluid holding means 36 (the pair of pole pieces 40 and 42) of the magnetic fluid sealing means 30 and 32 and the shaft member 2 is filled with the magnetic fluid 46.

Since the magnetic fluid sealing means 30 and 32 are disposed as described above, the magnetic fluid is sealed between the inside and the outside of the motor and both sides of the bearing members 12 and 14, and impurities inside the motor, for example, the bearing members 12 and 14 are sealed. Grease or the like used for the above is prevented from scattering to the outside.

In the illustrated spindle motor, oil absorbing means is further provided outside the bearing members 8 and 10. In the embodiment, an annular concave portion 50 is formed on the inner peripheral surface of the end wall 14 of the hub 4 corresponding to the bearing member 8. Further, an annular concave portion 52 is formed on the inner peripheral surface of the holding member 16 corresponding to the other bearing member 10. Oil absorbing means is accommodated in these annular concave portions 50 and 52. Although the concave portions 50 and 52 may have an appropriate cross-sectional shape, they are substantially V-shaped in the embodiment. The oil absorbing means may be any one that absorbs oil, and may be conveniently formed of a material such as cellulose, foamed resin or foamed rubber. This oil absorbing means is preferably comprised of a ring-like member 54 having some elasticity. When the magnetic fluid sealing means 30 (or 32) is mounted as required, it undergoes some elastic deformation and the end wall of the hub 4 is formed. It is desirable that the space between the mounting member 34 and the holding member 14 be substantially closed.

In the spindle motor having the above structure,
When oil is released from the grease filled in the bearing member 8, the released oil flows outward between the inner ring 56 and the outer ring 58 by the action of centrifugal force or the like when the hub 4 rotates. At this time, the mounting member 34 and the end wall 1 of the hub 4
As long as the oil is adhered to the end portion 4, the released oil does not flow between the end wall 14 and the mounting member 34, and therefore, the oil does not flow outside. on the other hand,
If the adhesion between the mounting member 34 and the end wall 14 is insufficient, the oil that has flowed out further passes between the outer ring 58 and the mounting member 34 and between the mounting member 34 and the hub 34 and outwards. It tends to flow toward. However, the end wall 14 of the hub 4
Since the ring-shaped member 54 is provided on the
Free oil flowing between the end wall 4 and the end wall 14 is absorbed by the ring-shaped member 54 and is prevented from flowing out.

The same applies to the other bearing member 10. That is, when oil is released from the grease filled in the bearing member 10, the released oil flows outward between the inner ring 60 and the outer ring 62 by the action of centrifugal force or the like when the hub 4 rotates. If the adhesion between the mounting member 34 and the holding member 16 is insufficient, the oil thus flowing further passes between the outer ring 58 and the mounting member 34 and between the mounting member 34 and the holding member 34. Tend to flow outward. However, since the ring-shaped member 54 is provided on the holding member 34, the free oil flowing between the mounting member 34 and the holding member 34 is absorbed by the ring-shaped member 54 and is prevented from flowing out. Is done.

FIG. 3 shows a part of a modification of the spindle motor. In this modification, the oil absorbing means is mounted on the mounting member of the magnetic fluid sealing means. 3, the same members as those in FIGS. 1 and 2 are described with the same reference numerals. In FIG. 3, one bearing member 8 side is deformed, and the mounting member 3 of the magnetic fluid sealing means 30 is mounted.
An annular concave portion 70 is formed on the outer peripheral surface of 4, and a ring-shaped member 72 as oil absorbing means is housed in the annular concave portion 70.

Also in this modified example, when oil released from the grease of the bearing member 8 flows between the hub 4 and the mounting member 34, the released oil is released from the ring-shaped member 72.
Is absorbed into the water and does not flow out. Therefore, also in this modified example, the same effect as that of the embodiment of FIGS. 1 and 2 is achieved.

Although the embodiment of the spindle motor according to the present invention has been described above, the present invention is not limited to such an embodiment, and various modifications and corrections can be made without departing from the scope of the present invention. .

For example, in the above-described embodiment, the bearing member 8
One ring-shaped member 54 is provided on the outside of (10), but a plurality of such ring-shaped members 54 are provided at intervals to increase the amount of free oil absorbed. You may.

Further, in the above-described embodiment, the description has been given by applying the present invention to a fixed shaft type spindle motor in which the hub 4 rotates with respect to the shaft member 2. However, the present invention can be similarly applied to a shaft rotating type spindle motor. it can. In this shaft rotation type spindle motor, a hub is rotatably supported with respect to a stationary member, and a shaft member provided on the hub is supported by the stationary member via a bearing member. Is mounted on a stationary member or a rotating shaft member.

Further, for example, in the above-described embodiment, the magnetic fluid sealing means 30 and 3 are provided outside the bearing members 8 and 10.
Although the present invention has been described as applied to the spindle motor having the form 2, the present invention can be similarly applied to a spindle motor having a labyrinth seal structure or a form having a sealing cap member.

[0024]

As described above, in the spindle motor of the present invention, since the oil absorbing means is provided outside the bearing member, when the oil released from the grease flows to the outside, the oil flows. The oil is absorbed by the oil absorbing means and does not flow out. Accordingly, the oil absorbing means reliably prevents the released oil from flowing out to the outside.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a partial section of an embodiment of a spindle motor according to the present invention.

FIG. 2 is a partially enlarged sectional view showing a part of the spindle motor of FIG. 1 in an enlarged manner.

FIG. 3 is a partially enlarged sectional view showing a part of a modification of the spindle motor in an enlarged manner.

[Explanation of symbols]

 2 Shaft member 4 Hub 8, 10 Bearing member 18 Stator 24 Rotor magnet 30, 32 Magnetic fluid sealing means 34 Mounting member 36 Magnetic fluid holding means 46 Magnetic fluid 50, 52 Annular recess 54 Ring-shaped member

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G11B 19/20 H02K 5/00-5/26 H02K 29/00-29/14

Claims (2)

(57) [Claims] A stationary shaft member, a hub on which a recording disk is mounted, a bearing member disposed between the stationary shaft member and the hub, a rotor magnet attached to the hub,
In a spindle motor including a stator disposed to face the rotor magnet, a magnetic fluid sealing means is disposed outside the bearing member,
The magnetic fluid sealing means includes an annular mounting member, and the mounting member.
Magnetic fluid holding means mounted on a magnetic fluid holding means
And a magnetic fluid held in the annular mounting member.
The magnetic shaft is attached to one of the stop shaft member and the hub.
Body filled between the other of them and the magnetic fluid holding means.
And the stationary shaft member on which the mounting member is mounted and the housing.
An annular recess is provided in the one of the bosses and / or the mounting member.
And the oil absorbing means is housed in the annular recess.
Spindle motor, characterized in that. 2. A stationary member and a recording disk mounted thereon.
A hub, a rotating shaft member provided on the hub, and the rotating shaft portion
A bearing member disposed between a member and the stationary member, and the hub
Rotor magnet attached to the rotor and the rotor magnet
Having a stator disposed opposite to the spindle
In the motor, magnetic fluid sealing means is provided outside the bearing member,
The magnetic fluid sealing means includes an annular mounting member, and the mounting member.
Magnetic fluid holding means mounted on a magnetic fluid holding means
And a magnetic fluid held in the annular mounting member.
The magnetic member is attached to one of the stop member and the rotating shaft member,
Fluid between the other and the magnetic fluid holding means.
The stationary member to which the mounting member is attached and
The one of the rotating shaft members and / or the mounting member has the annular shape.
A recess is provided, and the oil absorbing means is housed in the annular recess.
A spindle motor.