JP2580393Y2 - 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 hub on which a magnetic disk or the like is mounted by a motor.

[0002]

2. Description of the Related Art FIG.
As shown in FIG. In this motor, a shaft 2 is fixed to a frame 1, and two ball bearings 3 are fixedly arranged on the outer periphery of the shaft 2. A hub 4 is attached to the outer periphery of the ball bearings 3,3. The central portion of the hub 4 is formed in a cylindrical shape, and the upper and lower ends of the cylindrical central portion are open, so that the magnetic disk 5 is mounted on the outer periphery of the cylindrical central portion. A floating magnetic head 11 sought by an actuator (not shown) faces the magnetic disk 5. The upper end side opening of the hub 4 is covered with a seal cover 6 and fixed with an adhesive 7.

[0003] A stator core 8 is fixed to the frame 1, and a drive magnet 9 is fixed to the inner periphery of the hub 4. The stator core 8 has a plurality of salient poles, and a coil 10 is wound around each salient pole. The outer peripheral surface of the stator core 8 faces the inner peripheral surface of the rotor magnet 9 with a gap. A motor is constituted by the stator core 8, the rotor magnet 9, and the like, and the hub 4 is integrally rotated by urging the rotor magnet 9 to rotate. Between the outer periphery of the hub 4 to which the rotor magnet 9 is fixed and the frame 1, there is formed a labyrinth seal portion 12 in which concave and convex portions are intertwined with each other. The labyrinth seal portion 12 is provided to separate the space in which the magnetic disk 5 is mounted and the space of the motor.

[0004]

In the above spindle motor, when the hub 4 rotates, the lubricating oil of the ball bearings 3 and 3 becomes oil mist, and other dust scatters around. Labyrinth seal part 12
The dust such as oil mist is outside, especially the magnetic disk 5
The labyrinth seal portion 12 is formed to prevent dust such as oil mist from being scattered.

However, since the labyrinth seal portion 12 has a substantial space, the ball bearings 3, 3
Dust such as minute oil mist generated from the air cannot be completely shut off and may scatter on the magnetic disk 5. When dust such as oil mist scatters on the magnetic disk 5, the probability that a head crash occurs due to the dust, particularly in a high-density fixed magnetic disk device, since the flying height between the floating magnetic head 11 and the magnetic disk 5 is extremely small And the labyrinth seal portion 12 becomes insufficient in function.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem. By improving the sealing structure, it is possible to completely shut off the space as a dust source and the space on the magnetic disk surface. It is an object of the present invention to provide a spindle motor that can be used.

[0007]

The present invention provides a hub (25) on which a magnetic disk or the like is mounted and a pair of ball bearings (23, 2 ) rotatably supporting the hub (25).
4) and a fixed shaft (21).
Supports (21, 22) for holding rings (23, 24 )
A motor unit disposed in a space (A) surrounded by the support units (21, 22) and the hub (25) ;
Ball bearing (2) at the base side of the fixed shaft (21)
4) and the hub (25).
Between the supporting portion (21) and the supporting portion (21).
To form opposed flat portions (32, 33) extending in the radial direction with
A holder (30) for rotating the hub (25).
Therefore, an air flow directed toward the inside of the space (A) is generated.
The spiral groove (34) is connected to the opposed flat portion (3).
2, 33) formed on at least one of the members
I have.

[0008]

A spiral groove is formed on one of the opposing flat surfaces between the hub and the support so as to generate an air flow directed toward the inside of the space in which the motor and the like are disposed by the rotation of the rotor. With this configuration, it is possible to completely shut off the space serving as the dust generation source and the space on the magnetic disk surface, and even if the air flow containing the dust tries to flow out to the magnetic disk side, it is pushed back,
The scattering of dust such as oil mist generated from a ball bearing or the like into the space of the magnetic disk surface is prevented.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the spindle motor according to the present invention will be described below with reference to the drawings. In FIG. 1, a frame 21 constitutes a supporting portion.
A fixed shaft 22 is integrally formed in the center in the vertical direction. Further, inner rings of a pair of ball bearings 23 and 24 are fitted and fixed to the fixed shaft 22 while being vertically separated from each other. An inner peripheral surface of a center portion of a hub 25 formed in a substantially bell shape is fitted and fixed to the outer periphery of the outer ring of the ball bearing 23, and the hub 25 is rotatably supported on the fixed shaft 22. A magnetic disk is mounted on the outer periphery of the cylindrical central portion of the hub 25 in the same manner as in the above-described example. A floating magnetic head (not shown) faces the magnetic disk.

A stator core 26 is fixed between the pair of ball bearings 23, 24 of the frame 21.
A drive magnet 28 is fixed to the inner peripheral surface of the hub 25 via a rotor yoke 27. The rotor yoke 27
The outer periphery of the holder 30 is fixed to the lower end of the holder 30. The inner periphery of the holder 30 is fitted and fixed to the outer ring of the lower ball bearing 24. As described above, the enclosed space A is formed by the hub 25, the holder 30, and the frame 21. The lower surface of the holder 30 is opposed to the inner surface of the frame 21 so as to face the inner surface of the frame 21. A first opposed flat portion 32 is formed on the inner periphery of the lower ball bearing 24 side, and the outer peripheral side is formed. Has a second planar facing portion 33 formed at a position higher than the first facing planar portion 32.

On the other hand, the stator core 26 has a plurality of salient poles, and a coil 29 is wound around each salient pole. The outer peripheral surface of the stator core 26 faces the inner peripheral surface of the drive magnet 28 with a gap. These stator cores 2
6. A motor is constituted by the driving magnet 28, the coil 30, and the like. When the coil 30 is excited to urge the drive magnet 28 to rotate, the hub 25 rotates integrally.

An outer peripheral edge of an annular seal cover 31 is fitted and fixed to the inner periphery of the upper end of the upper end of the hub 25 so as to approach the upper end surface of the ball bearing 23. Further, a small gap is provided between the inner peripheral edge portion of the seal cover 31 and the fixed shaft 22 to form a labyrinth structure. Further, the ball bearing 2 of the seal cover 31 is used.
A spiral groove 35 is formed on the facing surface facing 3 as shown in FIG. The seal cover 31 formed with the spiral groove 35 is configured to rotate integrally with the hub 25, thereby generating an airflow toward the space A. Therefore, dust such as oil mist generated from the ball bearing 23 is prevented from scattering from the opening on one end side of the hub 25.

On the other hand, a spiral groove 34 as shown in FIG. 2 is formed in a first opposed flat surface portion 32 of the holder 30 which rotates integrally with the hub 25 and is opposed to the support portion formed of the frame 21. . The spiral groove 34 is configured such that the rotation of the holder 30 generates an airflow directed toward the space A via the lower ball bearing 24. Therefore, the space A having the dust generation sources such as the ball bearings 23 and 24
And the space having the magnetic disk can be completely shut off. Of course, even if the air flow containing dust tries to flow out to the magnetic disk side, it is pushed back by the action of the spiral groove 34 and the magnetic disk is Dust such as oil mist generated from the ball bearings 23 and 24 is prevented from being scattered in the space.

The spiral groove 34 described above can be formed on the second opposed flat portion 33 in addition to the first opposed flat portion 32. The spiral groove 34 may be formed on both the first and second opposed flat portions 32 and 33. Further, the spiral groove 34 is attached to the holder 30.
May be formed directly on a rotating member such as by milling, but as long as the air flow can be controlled in the space A direction as described above, no particular accuracy is required. It may be formed by a resin member.

[0015]

As is clear from the above description, the spindle motor of the present invention is provided with opposing flat portions that are close to and opposed to each other between the hub and the support portion, and constitutes the opposing flat portions.
A spiral groove is formed on at least one of the members to be rotated, and the rotation of the rotor generates an airflow directed toward the interior of the space in which the motor and the like are disposed. Not only can the surface space be completely blocked, but also the dust is pushed back by the air flow, and there is an advantage that the dust can be prevented from scattering into the space having the magnetic disk. Also support the hub by using the holder
Ball bearings can be separated from each other.
As a result, stable rotation performance can be obtained.
Furthermore, the opening side of the hub is closed by the holder.
The dust inside the motor is
It is possible to further prevent the particles from scattering between them.

[0016]

[0017]

[Brief description of the drawings]

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

FIG. 2 is a plan view showing a spiral groove formed in a facing flat portion of the hub.

FIG. 3 is a plan view showing a spiral groove formed on an opposing surface of a seal cover.

FIG. 4 is a sectional view showing a conventional spindle motor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 21 Frame (support part) 22 Fixed shaft 23, 24 Ball bearing 25 Hub 26 Stator core 27 Rotor yoke 28 Drive magnet 30 Holder 32, 33 Plane opposing part 34, 35 Spiral groove A space

Claims (2)

(57) [Scope of request for utility model registration] A hub (2 ) on which a magnetic disk or the like is mounted.
5) and a pair of rotatably supporting hubs (25) .
Ball bearings (23, 24) and fixed shaft (21)
And retain the ball bearings (23, 24).
Holding parts (21, 22) and the supporting parts (21 , 22).
A space (A) surrounded by 2) and the hub (25 )
And a root of the fixed shaft (21).
Side ball bearing (24) and the hub (25)
Coupled with each other, closely facing the support portion (21),
Opposing flat portion extending radially between the support portion and the support portion.
A holder (30) forming (32, 33);
Due to the rotation of the hub (25), the inside of the space (A)
Spiral groove (3
4) of the members constituting the opposed flat portions (32, 33)
A spindle motor formed on at least one side . 2. A side on which said holder (30) is provided.
Is a seal cover (3) at the opening of the hub (25) on the opposite side.
1) and fix the seal cover (31) to the fixed shaft.
On the end face of the ball bearing (23) on the tip side of (21)
The seal cover (31) is turned
The air flow that flows toward the inside of the space (A) is generated by rolling.
Spiral spiral groove (35) is attached to the seal cover
2. The method according to claim 1, wherein the first surface is formed on the bearing-side facing surface.
The spindle motor as described.