JPH08140323A - Spindle motor for disk drive - Google Patents

Abstract

PURPOSE: To provide a spindle motor, for a disk drive, which is low-cost, by which the recording and reproducing operation of a disk can be performed stably and whose reliability is excellent. CONSTITUTION: A spindle motor for a disk drive is provided with a shaft 1 and with a housing 4 which supports and bears the shaft 1 via bearings 2, 3. In the spindle motor, a side pressure adding means 9 which biases the shaft 1 in its radial direction so as to bring the shaft 1 into contact with prescribed parts of the bearings 2, 3 is installed, and a prescribed contact state is maintained at the shaft and the bearings.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disk drive, for example, a disk drive spindle motor in a CD-ROM drive or a magneto-optical disk drive.

[0002]

2. Description of the Related Art A conventional disk drive device such as a CD
In a disk drive spindle motor used in a ROM drive, a magneto-optical disk drive, or the like, a shaft arranged at the center thereof is rotatably supported by a housing or the like via a bearing. Usually, some of these motors use bearings such as ball bearings at two positions in the axial direction, and a method of suppressing play between the shaft and the bearing by applying a preload to the ball bearing itself has been adopted. In addition, recently, there are some which use a dynamic pressure bearing in order to suppress the looseness between the shaft and the bearing.

[0003]

However, even if a preload is applied to the ball bearing itself in order to suppress the play between the shaft and the bearing, the play cannot always be suppressed to zero, and the spindle of a CD-ROM drive or the like cannot be suppressed. In the motor, if this backlash is present, vibration is generated during rotation, and this vibration adversely affects reading of the disk and the like. Also, when oil-less metal is used as the bearing, if there is looseness between the shaft and the bearing, the oil will not be lubricated smoothly and the contact noise between the shaft and the bearing will occur. However, the life of the motor is also negatively affected. Further, the use of a dynamic pressure bearing is very costly and difficult to handle, which is practically disadvantageous.

SUMMARY OF THE INVENTION It is, therefore, an object of the present invention to solve the above problems and provide a highly reliable disk drive spindle motor capable of stably recording and reproducing a disk at low cost.

[0005]

DISCLOSURE OF THE INVENTION A disk drive spindle motor according to the present invention is a disk drive spindle motor having a shaft and a housing for supporting the shaft via a bearing. A lateral pressure applying means for urging the bearing into contact with a predetermined portion of the bearing is provided. The side pressure applying means is attached to the hollow disk-shaped auxiliary plate fixed to the housing in a state where the shaft is inserted, a rising portion protruding from a flat surface portion of the auxiliary plate, and the rising portion. The recess may be provided and a side pressure member that is elastic while engaging with the recess. The lateral pressure member is preferably a piano wire coated with a resin. Further, the lateral pressure applying means may be a hollow cylindrical elastic body arranged in a space defined by the bearing and the housing. The elastic body is preferably a porous oil-containing resin.

[0006]

By providing the side pressure applying means for urging the shaft in the radial direction to bring it into contact with a predetermined portion of the bearing, the shaft and the bearing can be kept in a predetermined contact state.

[0007]

[First Embodiment] FIG. 1 is a sectional view of a main part of a disk drive spindle motor showing a first embodiment of the present invention.
FIG. 2 is a perspective view showing the lateral pressure adding means in FIG.

In FIG. 1, reference numeral 1 is a shaft, and bearings 2 and 3 composed of two ball bearings are respectively fitted in the shaft 1 in the axial direction, and the shaft 1 is housing through the bearings 2 and 3. 4 is rotatably supported. An iron core 5 formed by laminating a plurality of thin plates such as silicon steel plates is fixed to the housing 4, and the iron core 5 is provided with a coil 6 formed by winding a winding a plurality of times. On the other hand, a cup-shaped yoke 7 is fixed to a predetermined portion of the shaft 1 via a boss. A magnet 8 is attached to the yoke 7, and the magnet 8 is arranged in the yoke 7 so as to be separated from the iron core 5 having the coil 6 by a predetermined gap.

Here, a lateral pressure adding means 9 for applying a lateral pressure to the shaft 1 is provided above the bearing 3. The side pressure adding means 9 has a structure as shown in FIG. Figure 2
In the above, reference numeral 9a is an auxiliary plate formed in the shape of a hollow disk, and a part thereof is provided with a rising portion 9b formed at a right angle to the flat surface portion of the auxiliary plate 9a by bending. The rising portion 9b is formed with a recess 9c whose one end is open up to a predetermined portion of the rising portion 9b. The rising portion 9b may be configured as a member different from the auxiliary plate 9a. Further, 9d is a lateral pressure member, and the lateral pressure member 9d includes, for example, an elastic wire, but in consideration of low friction, a piano wire coated with a resin is preferable.

The side pressure member 9d is attached to the recess 9c formed in the rising portion 9b of the auxiliary plate 9a, but the side pressure member 9d inserted from the open end is regulated midway. ing. Note that the recess 9c does not have to be particularly open, and may be, for example, a circular hole. In attaching the lateral pressure applying means 9 having such a configuration, first, the lateral pressure member 9d is engaged with the recess 9c, and the shaft 1 is inserted into the hollow portion of the auxiliary plate 9a.
And the auxiliary plate 9a is fixed to the housing or the like by adhesion or the like. On the other hand, the lateral pressure member 9d maintains its stationary state because its radial movement is restricted by the shaft 1 and the rising portion 9b.

Next, a specific side pressure applying structure will be described. When the side pressure applying means 9 is attached as described above, the elastic side pressure member 9d is deformed into an arc shape by the shaft 1,
In this state, a force for radially urging the shaft 1 is generated in the lateral pressure member 9d. Due to this urging force, the shaft 1 always maintains a state of being in contact with the inner rings of the bearings 2 and 3. It should be noted that upon mounting, a force that finally biases the shaft 1 in the radial direction may be generated, and the mounting method is not particularly limited.

[0012]

[Second Embodiment] FIG. 3 is a sectional view of a main portion of a disk drive spindle motor showing a second embodiment of the present invention.
In FIG. 3, the same parts as those in FIG. 1 are denoted by the same reference numerals. A difference from FIG. 1 is a mounting position of the lateral pressure applying means 9, and the lateral pressure applying means 9 is arranged in a space defined by the bearings 2 and 3 and the housing 4. In this way, the lateral pressure adding means 9 is not affected by the outside, so that a highly accurate lateral pressure adding mechanism can be provided. Besides, the lateral pressure applying means 9 may be provided at two locations in the axial direction.

[0013]

[Third Embodiment] FIG. 4 is a sectional view of a main portion of a disk drive spindle motor showing a third embodiment of the present invention.
Further, FIG. 5 is a perspective view showing the lateral pressure adding means in FIG.

In FIG. 4, parts similar to those in FIG. 1 or 3 are denoted by the same reference numerals. In FIG. 4, FIG.
Instead of the side pressure adding means 9 of No. 3, another side pressure adding means 10 is used. This side pressure adding means 10 is shown in FIG. In FIG. 5A, the lateral pressure adding means 10 is made of a resin-based elastic body formed in a hollow cylindrical shape. As shown in FIG. 4, when the elastic body is arranged in the space formed by the bearings 2 and 3 and the housing 4, the elastic body is deformed by the shaft 1 as shown in FIG. Then, a restoring force in the radial direction is generated in the elastic body in an attempt to restore the original shape. This force acts to urge the shaft 1 in the radial direction, and the shaft 1 maintains the state in which the lateral pressure is applied.

If the elastic body is made of a porous oil-impregnated resin, the life is improved. Further, the elastic body may be provided at two locations in the axial direction. Although the rolling bearings are described in detail in each of the above-mentioned embodiments, the present invention is not limited to this, and can be applied to sliding bearings and the like.

[0016]

As described above, according to the present invention, by providing the side pressure applying means for urging the shaft in the radial direction to bring it into contact with a predetermined portion of the bearing, the play between the shaft and the bearing is prevented. It is possible to provide a spindle motor for driving a disk that is highly reliable in recording and reproduction. Further, if the side pressure adding means is composed of the hollow disk-shaped auxiliary plate and the side pressure member, it is possible to suppress backlash between the shaft and the bearing with a simple structure, so that it can be provided at low cost. If a piano wire coated with resin is used for this side pressure member, loss due to friction can be prevented and a long-life motor can be provided. Further, if the lateral pressure applying means is made of a hollow cylindrical elastic body, it is very easy to handle. If a porous oil-containing resin is used for this elastic body, loss due to friction can be prevented and a long-life motor can be provided.

[0017]

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part of a disk driving spindle motor showing a first embodiment of the present invention.

FIG. 2 is a perspective view showing a lateral pressure adding means in FIG.

FIG. 3 is a cross-sectional view of essential parts of a disk drive spindle motor showing a second embodiment of the present invention.

FIG. 4 is a cross-sectional view of essential parts of a disk drive spindle motor showing a third embodiment of the present invention.

FIG. 5 is a perspective view showing a lateral pressure adding means in FIG.

[Explanation of symbols]

 1 ... Shaft 2, 3 ... Bearing 4 ... Housing 5 ... Iron core 6 ... Coil 7 ... Yoke 8 ... Magnet 9, 10 ... Side pressure applying means

Claims (5)

[Claims] 1. A disk drive spindle motor having a shaft and a housing for supporting the shaft via a bearing, wherein lateral pressure is applied to urge the shaft in the radial direction to abut against a predetermined portion of the bearing. A spindle motor for driving a disk, characterized by comprising means. 2. The side pressure applying means includes a hollow disc-shaped auxiliary plate fixed to the housing in a state where the shaft is inserted, and a rising portion protruding from a flat surface portion of the auxiliary plate. 2. A recess formed in the rising portion, and a side pressure member that is elastic while engaging with the recess.
The disk drive spindle motor described. 3. The disk drive spindle motor according to claim 2, wherein the lateral pressure member is a resin-coated piano wire. 4. The disk drive spindle motor according to claim 1, wherein the lateral pressure applying means is a hollow cylindrical elastic body disposed in a space defined by the bearing and the housing. 5. The disk drive spindle motor according to claim 4, wherein the elastic body is a porous oil-containing resin.