JP3174173B2 - 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 used for rotating a recording medium.

[0002]

2. Description of the Related Art As a motor used for driving a recording medium, for example, a magnetic disk drive, a spindle motor driven by a DC power supply is known. In this type of spindle motor, the rotation fixing member, and a rotary member which is rotatably supported with respect to the fixed member, provided with a stator having a coil on the fixed member side, the magnet opposing the stator A relatively widely adopted configuration is provided on the member side, in which a direct current is applied to the coil, and the rotating member is rotated by an electromagnetic induction effect between a magnetic field induced in the coil and a magnet.

[0003] In such a spindle motor, a mechanism for rotatably supporting a rotating member generally uses a ball bearing. In such a bearing, lubrication such as grease is performed in order to ensure smooth operation. The agent is filled. However, when the bearing is filled with lubricant,
Due to the rotation of the rotating member, fine particles of the lubricant leak to the outer periphery of the rotating member on which the magnetic disk is mounted, and adhere to the surface of the magnetic disk, causing head stiction.

Therefore, conventionally, for example, Japanese Patent Publication No. 4-22
As disclosed in Japanese Patent Publication No. 297, a labyrinth seal portion is provided on the bearing to prevent leakage of the lubricant. However, such a means for preventing leakage of the lubricant has the following technical problems.

[0005]

That is, in the spindle motor disclosed in the above publication, a labyrinth-shaped labyrinth seal portion is provided by attaching a metal or rubber ring member to a bearing portion. Since the seal portion is maze-shaped, leakage of the lubricant can be suppressed for a relatively long time, but leakage cannot be completely prevented.

[0006] The present invention has such has been made in view of the conventional problems, and an object is to provide a spindle motor which leakage of lubricant can be reduced as much as possible .

[0007]

In order to achieve the above object, the present invention provides a rotating member having a magnet and a recording medium mounted on an outer periphery, a fixed member having a stator facing the magnet, A spindle motor interposed between the rotating member and the solid member, the bearing having a labyrinth seal portion ;
An annular protrusion protruding inward is provided on the inner periphery of the labyrinth.
An inner peripheral end of the annular projection provided near the seal portion.
And the outer peripheral surface of the fixing member face each other with a minute gap therebetween.
In this case, the labyrinth seal portion is provided with a continuous seal portion .

[0008] The fixing member may be provided with an annular projection for preventing the flow of a curable synthetic resin for fixing the coil of the stator.

[0009]

According to the spindle motor having the above construction, the labyrinth seal portion is provided on the bearing, and the labyrinth seal portion is provided in the vicinity of the labyrinth seal portion so that the rotating member and the fixed member face each other at a small interval. The lubricant leaking from the seal portion is further prevented from leaking at the seal portion, so that it is possible to greatly reduce the leakage of the lubricant.

According to the second aspect of the present invention, the curable synthetic resin absorbs the vibration when the coil is energized, improves the electrical insulation, and reduces the flow of the curable synthetic resin by the annular projection. This prevents the resin from flowing to the rotating member.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 shows an embodiment of a spindle motor according to the present invention. The spindle motor shown in FIG. 1 has a bracket (fixing member) 10 having a substantially concave cross-section, and the bracket 10 is located inside a ring-shaped flange portion 10a provided on the outermost periphery. Outer peripheral wall portion 10b and outer peripheral wall portion 10b
Has an annular first bottom portion 10c formed at the lower portion inward, and an annular projection portion 10d provided on the inner peripheral side of the annular first bottom portion 10c.

An annular second bottom portion 10e is formed on the inner peripheral side of the annular projection 10d. A large-diameter inner peripheral wall portion 10f and a small-diameter inner peripheral wall portion 10g are formed on the inner peripheral side of the second bottom portion 10e. Is provided. And the outer peripheral wall portion 10b and the bottom portions 10c, 1
0e and the large-diameter inner peripheral wall 10f, the inner and outer peripheral wall 10
First and second annular concave portions 12a, 12b opened upward are formed between b, 10f. At the center of the inner peripheral wall portions 10f and 10g of the bracket 10, a cylindrical fixed support 1 is provided.
The lower end of 4 is fitted and fixed. The lower end of the fixed support 14 has a large diameter and a small diameter inner peripheral wall 1 of the bracket 10.
It projects upward from the bracket 10 in a state in which approximately 嵌合 of the entire length thereof is fitted and fixed in a through hole 16 formed in 0f and 10g.

On the other hand, the large-diameter inner peripheral wall 10 of the bracket 10
A stator core 22 is fixed to the outer peripheral surface of f, and a stator coil 24 is wound around the stator core 22. In this embodiment, the stator core 22 is installed so that there is some gap between the lower surface on the outer end side and the tip of the annular projection 10d of the bracket 10, and the stator coil 22 is provided with a large-diameter inner peripheral wall portion. It is fixed by thermosetting synthetic resin 26 filled between 10f and annular projection 10d.

In this case, the annular protrusion 10d is provided to prevent the leakage of the thermosetting synthetic resin 26. When the thermosetting synthetic resin 26 is energized, While absorbing the vibration of 24,
It is interposed between the coil 24 and the second bottom portion 10e to ensure electrical insulation. In FIG.
Reference numeral 8 denotes a rotor hub (rotating member) formed in a substantially bowl shape. The rotor hub 28 includes a base 28a through which a fitting hole 30 penetrates in the center, a flange 28b formed on the outer periphery of the base 28a, An outer wall portion 28c is formed to hang down from an outer end of the flange portion 28b, and a hollow cylindrical portion 28d is formed on an inner peripheral upper portion of the base portion 28a.

In this embodiment, a plurality of hard disks are externally fitted and fixed on the upper side of the flange portion 28b on the outer periphery of the base portion 28a with a spacer interposed therebetween. In addition, a cylindrical rotor magnet 32 is disposed on the inner peripheral side of the outer wall portion 28c and opposed to the stator core 22, and the rotor magnet 32 is fixed to the inner surface of the outer wall portion 28c.

The rotor hub 28 configured as described above is
By mounting the first and second bearings 34 and 36 in the fitting holes 30 and inserting the fixed columns 14 into the bearings 34 and 36, the fixed columns 14 are rotatably supported by the bracket 10. In this embodiment, the bearings 34 and 36 are constituted by ball bearings. Each of the bearings 34 and 36 has an inner ring 34a, 36a and a ball 34b,
36b and outer rings 34c and 36c.

The first and second bearings 34, 36
A cylindrical spacer 38 is interposed between them so that the fitting hole 3
It is mounted in 0. In the first bearing 34 located on the lower side in this mounted state, a seal ring 40 is provided on the inner peripheral surface side of the outer ring 34c and adjacent to the outer peripheral surface of the inner ring 34a at a small interval. When mounting the rotor hub 28 on the bracket 10,
The rotor hub 28 is attached to the fixed support 14 after a metal washer 42 is fitted to the outer periphery of the fixed support 14.

In the rotation support portion of the rotor hub 28 thus configured, a maze space is formed between the upper and lower surfaces of the seal ring 40 and the upper surface of the washer 42, and the bearings 34 and 36 are filled. The labyrinth seal prevents leakage of the lubricant. Further, in this embodiment, a seal portion 44 is provided near the lower part of the labyrinth seal portion.

The seal portion 44 has an annular projecting portion 44a projecting inward at a lower portion of the inner periphery of the base portion 28a of the rotor hub 28.
It is constituted by facing the outer peripheral surface of the small-diameter inner peripheral wall portion 10g at a small interval. In this case, the size of the minute interval is, for example, about 0.2 mm, which is such that smooth rotation of the rotor hub 28 is not alienated. In FIG. 1, a member indicated by reference numeral 46 is a cap fitted over and fixed to the hollow cylindrical portion 28d in order to cover the upper part of the second bearing 36 and prevent the lubricant from leaking from the upper side. is there.

In the spindle motor configured as described above, a DC current is applied to the stator coil 24, and the rotor hub 28 is rotated by the electromagnetic induction between the magnetic field generated in the coil 24 and the magnet 32.
With this rotation, the lubricant filled in the bearings 34, 36 is removed from the first and second annular spaces 12a, 12a.
b, the rotor hub 28 on which the disk is mounted
At this time, the seal ring 40 and the washer 4
Since the labyrinth seal portion composed of the above 2 is interposed, first, the leakage of the lubricant is prevented by the labyrinth seal portion.

Even if the lubricant gradually leaks through the labyrinth seal with the passage of time, since the seal 44 is provided near the lower part of the labyrinth seal, the lubricant leaking from the labyrinth seal is provided. The agent is prevented from leaking at the seal portion 44. In this case, since the seal portion 44 is configured such that the inner peripheral end of the annular protrusion 44a is opposed to the outer peripheral surface of the small-diameter inner peripheral wall portion 10g of the bracket 10 at a small interval, the seal portion 44 passes through the minute interval. No lubricant flows.

In the above embodiment, the stator coil 2
4 is fixed to the second bottom portion 10e by the thermosetting synthetic resin 26, so that when the coil 24 is energized, its vibration is absorbed and reduced by the synthetic resin 26, and the coil 24 and the second bottom portion 10e are connected to each other. The electrical insulation between the two is also synthetic resin 26
And can be kept good. Further, in the above embodiment,
Since the annular projection 10 d is provided on the bracket 10, when the stator coil 24 is fixed with the synthetic resin 26, it is also possible to prevent the leakage of the synthetic resin before being hardened.

In the above embodiment, the rotor hub 28 is rotatably supported on the bracket 10 by the two bearings 34 and 36. However, the present invention is not limited to this. The present invention can also be applied to a configuration in which the unit is supported by one unit bearing. Further, a flat ring member made of synthetic resin may be used instead of the metal washer 42.

[0024]

As described above in detail in the embodiments,
ADVANTAGE OF THE INVENTION According to the spindle motor concerning this invention, it becomes possible to reduce the possibility of the leakage of the lubricant filled in a bearing as much as possible.

[Brief description of the drawings]

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

[Explanation of symbols]

 Reference Signs List 10 bracket (fixing member) 24 stator coil 28 rotor hub (rotating member) 32 rotor magnet 34 first bearing 36 second bearing 40 seal ring 42 washer 44 seal portion

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-1-157255 (JP, A) JP-A-2-309066 (JP, A) JP-A-4-76149 (JP, U) JP-A-3-157066 50955 (JP, U) (58) Fields surveyed (Int. Cl. ⁷ , DB name) H02K 5/173 H02K 5/10

Claims (2)

(57) [Claims] A labyrinth interposed between the rotating member and the fixed member, a rotating member having a magnet and having a recording medium mounted on an outer periphery thereof, a fixed member having a stator facing the magnet, and a rotating member interposed between the rotating member and the fixed member. In a spindle motor including a bearing having a seal portion, an annular projection protruding inward is formed on an inner peripheral portion of the rotating member.
The annular protrusion is provided near the labyrinth seal portion.
A minute gap is formed between the inner peripheral end of the raised portion and the outer peripheral surface of the fixing member.
The labyrinth seal portion is opposed by a distance.
A spin torque motor characterized in that a continuous seal portion is provided on the motor. 2. The spintor according to claim 1, wherein the fixing member is provided with an annular protrusion for preventing a flow of a curable synthetic resin for fixing the coil of the stator. motor.