JPH06165434A - Spindle motor - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a spin-trail motor that can reduce leakage of lubricant as much as possible. [Configuration] The motor has a bracket 10 and a rotor hub 28. The rotor hub 28 includes the first and second bearings 3
4,36 are mounted and rotatably supported with respect to the bracket 10. The first and second bearings 34 and 36 are spacers 38
It is mounted in the fitting hole 30 with the intervening. The first bearing 34 is provided with a seal ring 40 on the inner peripheral surface side of the outer ring 34c and in close proximity to the outer peripheral surface of the inner ring 34a with a minute gap,
A washer 42 is provided on the lower surface side. In the rotation support portion of the rotor hub 28 thus configured,
A labyrinth-like space is formed between the upper and lower surfaces of the seal ring 40 and the upper surface of the washer 42, and this portion serves as a labyrinth seal portion. Near the lower part of the labyrinth seal, an inwardly projecting annular protrusion 44a is formed at the lower inner peripheral portion of the base portion 28a of the rotor hub. Seal part
44 are formed.

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 device, a spindle motor driven by a DC power source is known. In this type of spindle motor, a fixed member and a rotating member rotatably supported by the fixed member are provided, a stator having a coil is provided on the fixed member side, and a magnet facing the stator is provided as a rotating member. A configuration in which a rotating member is rotated on the side by rotating a rotating member by an electromagnetic induction action between a magnetic field induced in the coil and a magnet by applying a direct current to the coil is relatively widely adopted.

In such a spindle motor, a ball bearing is generally used as a mechanism for rotatably supporting a rotating member, and in such a bearing, lubrication such as grease is applied in order to ensure smooth operation. It is filled with agent. However, when the bearing is filled with lubricant,
Due to the rotation of the rotating member, the 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 bearing is provided with a labyrinth seal portion to prevent the lubricant from leaking. However, such lubricant leakage prevention means has the technical problems described below.

[0005]

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

The present invention has been made in view of such conventional problems, and an object of the present invention is to provide a spin-trail motor capable of reducing leakage of lubricant as much as possible. .

[0007]

In order to achieve the above object, the present invention has a rotating member having a magnet on which a recording medium is mounted, and a fixing member having a stator facing the magnet. In a spindle motor provided with a bearing having a labyrinth seal portion, which is interposed between the rotary member and the fixed member, in the vicinity of the labyrinth seal portion, the rotary member and the fixed member are separated by a minute interval. It is characterized in that opposing seal portions are provided.

The fixing member may be provided with an annular protrusion for preventing the flow of the 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 in the bearing, and the rotary member and the fixed member are provided in the vicinity thereof with the seal portion facing each other with a minute gap therebetween. The lubricant leaking from the seal portion is further prevented from leaking at the seal portion, and the leak of the lubricant can be extremely reduced.

Further, according to the second aspect of the present invention, the curable synthetic resin absorbs the vibration when the coil is energized, the electrical insulation is improved, and the annular projection allows the curable synthetic resin to flow. This prevents the resin from flowing to the rotating member.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described in detail below 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 the figure has a bracket (fixing member) 10 having a substantially concave cross section, and the bracket 10 is located at the innermost ring-shaped flange portion 10a provided on the outermost periphery. Outer peripheral wall portion 10b and its outer peripheral wall portion 10b
It has an annular first bottom portion 10c formed on the inner lower part of the above, and an annular projection portion 10d provided on the inner peripheral side of this annular first bottom portion 10c.

An annular second bottom portion 10e is formed on the inner peripheral side of the annular protrusion 10d, and 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. It is provided. 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 recesses 12a and 12b that are open upward are formed between b and 10f. At the center of the inner peripheral wall portions 10f and 10g of the bracket 10, the columnar fixed column 1
The lower end side of 4 is fitted and fixed. The fixed column 14 has a lower end portion having a large diameter and a small diameter inner peripheral wall portion 1 of the bracket 10.
Approximately ½ of the entire length is fitted and fixed in the through holes 16 formed in the holes 0f and 10g, and is projected upward from the bracket 10.

On the other hand, the large-diameter inner peripheral wall portion 10 of the bracket 10
A stator core 22 is fixedly provided on 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 thereof and the tip of the annular projection 10d of the bracket 10, and the stator coil 22 has a large-diameter inner peripheral wall portion. It is fixed by a thermosetting synthetic resin 26 filled between 10f and the annular protrusion 10d.

In this case, the annular protrusion 10d is provided to prevent the thermosetting synthetic resin 26 from leaking out, and the thermosetting synthetic resin 26 is applied to the coil of the stator coil 24 when the stator coil 24 is energized. While absorbing the vibration of 24,
The coil 24 and the second bottom portion 10e are interposed to ensure electrical insulation. In FIG. 1, reference numeral 2
Reference numeral 8 denotes a rotor hub (rotating member) formed in a substantially bowl shape, and the rotor hub 28 has a base portion 28a through which the fitting hole 30 penetrates in the central portion, and a flange portion 28b formed on the outer periphery of the base portion 28a. It has an outer wall portion 28c formed so as to hang down from the outer end of the flange portion 28b, and a hollow cylindrical portion 28d formed on the upper side of the inner periphery of the base portion 28a.

In this embodiment, a plurality of hard disks are fitted and fixed on the outer periphery of the base portion 28a on the upper side of the flange portion 28b with spacers interposed. Further, a cylindrical rotor magnet 32 is arranged at a position facing the stator core 22 on the inner peripheral side of the outer wall portion 28c, 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 hole 30 and inserting the fixed column 14 into the bearings 34 and 36, the bracket 10 is rotatably supported with respect to the bracket 10. The bearings 34 and 36 are ball bearings in this embodiment, and each of the bearings 34 and 36 includes an inner ring 34a and 36a, a ball 34b, and a ball 34b.
36b and outer rings 34c and 36c.

The first and second bearings 34 and 36 are
The cylindrical spacer 38 is interposed between these and the fitting hole 3
It is installed in 0. The first bearing 34, which is located on the lower side in this mounted state, is provided with a seal ring 40 on the inner peripheral surface side of the outer ring 34c thereof, which is close to the outer peripheral surface of the inner ring 34a with a minute gap. Further, when the rotor hub 28 is mounted on the bracket 10, the fixed support 14
After fitting the metal washer 42 to the outer periphery of the rotor hub 28, the rotor hub 28 is attached to the fixed column 14.

In the rotation support portion of the rotor hub 28 thus constructed, a space on the maze 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 with the space. It is a labyrinth seal that prevents the lubricant from leaking. Further, in this embodiment, the seal portion 44 is provided near the lower portion of the labyrinth seal portion.

The seal portion 44 is formed with an annular protrusion 44a projecting inward at the lower portion of the inner periphery of the base portion 28a of the rotor hub 28, and the inner peripheral end of the annular protrusion 44a is attached to the bracket 1.
It is configured to face the outer peripheral surface of the small-diameter inner peripheral wall portion 10g of 0 at a small interval. In this case, the size of the minute interval is, for example, about 0.2 mm, which is an interval that does not prevent smooth rotation of the rotor hub 28. In addition, in FIG. 1, a member indicated by reference numeral 46 is a cap which covers the upper side of the second bearing 36 and is fitted and fixed to the hollow cylindrical portion 28d in order to prevent the lubricant from leaking from the upper side. is there.

In the spindle motor constructed as described above, a DC current is passed through the stator coil 24, and the rotor hub 28 is rotated by the electromagnetic induction effect of the magnetic field generated in the coil 24 and the magnet 32.
Along with this rotation, the lubricant filled in the bearings 34, 36 causes the lubricant to fill the first and second annular spaces 12a, 12
The rotor hub 28 to which the disc is mounted via b
Of the seal ring 40 and the washer 4 in the lubricant leakage path.
Since the labyrinth seal portion composed of 2 and 3 is interposed, the lubricant is first prevented from leaking at the labyrinth seal portion.

Even if the lubricant leaks gradually through the labyrinth seal portion with the passage of time, since the seal portion 44 is provided near the lower portion of the labyrinth seal portion, the lubricant leaked from the labyrinth seal portion is lost. 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 portion of the annular protrusion 44a faces the outer peripheral surface of the small-diameter inner peripheral wall portion 10g of the bracket 10 with a minute gap therebetween, the seal portion 44 passes through this minute gap. The lubricant does not flow.

Further, in the above embodiment, the stator coil 2
Since 4 is fixed to the second bottom portion 10e by the thermosetting synthetic resin 26, when the coil 24 is energized, its vibration is absorbed and relaxed by the synthetic resin 26, and the coil 24 and the second bottom portion 10e are The electrical insulation between
Can keep good at. Further, in the above embodiment,
Since the bracket 10 is provided with the annular protrusion 10d, when the stator coil 24 is fixed with the synthetic resin 26, it is possible to prevent the synthetic resin from leaking out before being cured.

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. It can also be applied to a structure that is supported by one unit bearing. Further, a flat ring member made of synthetic resin can be used instead of the metal washer 42.

[0024]

As described above in detail in the embodiments,
According to the spindle motor of the present invention, it is possible to reduce the possibility of leakage of the lubricant filled in the bearing as much as possible.

[Brief description of drawings]

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

[Explanation of symbols]

 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

Claims (2)

[Claims] 1. A labyrinth, which has a magnet, a rotary member on the outer periphery of which a recording medium is mounted, a fixed member having a stator facing the magnet, and a rotary member interposed between the rotary member and the fixed member. A spindle motor provided with a bearing having a seal part, wherein a spinr motor is provided in the vicinity of the labyrinth seal part, wherein the rotary member and the fixed member are opposed to each other with a minute gap therebetween. 2. The spintor according to claim 1, wherein the fixing member is provided with an annular protrusion for preventing the flow of the curable synthetic resin for fixing the coil of the stator. motor.