JP2558213Y2 - Motor and magnetic disk drive using this 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 motor and a magnetic disk drive using the motor, and more particularly to a structure of a rotary bearing.

[0002]

2. Description of the Related Art As a conventional magnetic disk drive of this type, for example, there is one as shown in FIG. That is,
This magnetic disk drive is composed of a rotating magnetic disk medium 1.
01, a magnetic head 1 floated through a minute gap
02 is a storage device for recording and reading data on the magnetic disk medium 101 by moving the magnetic disk medium 101, a mechanism for rotating the magnetic disk medium 101, and a magnetic head 1
02 is driven.

A mechanism for rotating the magnetic disk medium 101 includes a disk drive motor 103 such as a spindle motor.
, A rotating shaft 104, and a rolling bearing 105 supporting the rotating shaft 104.
Seal 108 that seals dust and mist of the rolling bearing 105 entering the inside with a magnetic fluid 107
It has.

Similarly, a mechanism for driving the magnetic head 102 includes a head driving motor 109 such as a voice coil motor, a rotating shaft 104 ', and a rolling bearing 105'.
And a magnetic fluid seal 108 '.

[0005]

However, the above-mentioned conventional magnetic disk drive has the following problems.

That is, the rolling bearings 105, 105 '
Is used, there is a problem that the deflection of the rotating shafts 104 and 104 'is large, there is a problem in reliability, and an abnormal sound is easily generated by the vibration.

Further, since the rolling bearings 105, 105 'and the magnetic fluid seals 108, 108' are arranged in the longitudinal direction of the shaft, there is a problem that it is difficult to reduce the thickness of the device.

Further, as shown in FIG. 5, a general motor having a permanent magnet 111 and an armature 112 is used as the disk driving and head driving motors 103 and 109. The rolling bearing 114 was used as the bearing for the above. Therefore, it is difficult to increase the rotational accuracy of the drive shaft 113, and a problem occurs that the drive of the magnetic disk medium 101 and the magnetic head 102 is adversely affected.

There are also problems such as mist generated in the rolling bearing 114 and dust in the motor flowing out, and conversely, intrusion of dust into the motor.

The present invention has been made to solve the above-mentioned problems of the prior art, and an object of the present invention is to improve the sealing performance and rotation accuracy of a motor by using a magnetic fluid bearing. .

Further, by using this motor for the magnetic disk drive and using a magnetic fluid bearing for the rotation mechanism of the magnetic disk medium and the drive mechanism of the magnetic head, vibration during rotation driving of the magnetic disk and the magnetic head can be prevented. To improve the reliability and reduce the size of the device.

[0012]

In order to achieve the above object, according to the present invention, an armature, a stator having a permanent magnet disposed so as to surround the armature, and an integral part of the armature are provided. a drive shaft which is provided, in a motor provided with the bearing instructing rotatably to the drive shaft, Rutotomoni using a magnetic fluid bearing as the bearing, the magnetic flow of the magnetic fluid bearing
The permanent magnet of the stator works as a magnetic source for holding the body.
The feature is to use a magnetic field .

[0013]

It is effective that the magnetic fluid of the magnetic fluid bearing is filled in a radial gap between the stator and the drive shaft and a thrust gap between the armature and the stator.

[0015] Another invention is a magnetic disk medium,
In a magnetic disk device including a magnetic head, a mechanism for rotating the magnetic disk medium, and a mechanism for driving the magnetic head, as a drive source of a mechanism for rotating the magnetic disk medium and a mechanism for driving the magnetic head, And the motor described above .

[0016]

In the motor having the above structure, the drive shaft is supported by the magnetic fluid bearing via the magnetic fluid, so that the rotation is smooth with respect to the rolling bearing, and the shaft runout and the like can be suppressed. Further, the rotating surface is sealed by the magnetic fluid, so that the motor can be sealed.

Further, by using the magnetic field generated by the permanent magnet of the stator as a magnetic force source for holding the magnetic fluid, the motor can be reduced in size and weight.

Further, the magnetic disk drive of the present invention uses a magnetic fluid bearing for both the mechanism for rotating the magnetic disk medium and the mechanism for driving the magnetic head, thereby preventing generation of dust and reducing noise. Becomes

Further, when a magnetic fluid bearing is used as a mechanism for driving the magnetic head, not only generation of dust is prevented, but also positioning accuracy and speed of the magnetic head are improved by reducing friction, and damping of the magnetic fluid is further performed. The effect suppresses the vibration of the driving unit and improves the reliability.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the illustrated embodiment. In FIG. 1 showing a magnetic disk device according to an embodiment of the present invention, the magnetic disk device includes a magnetic disk medium 1, a mechanism for rotating the magnetic disk medium 1, a magnetic head 2, and a magnetic head 2. And a driving mechanism.

The magnetic disk 1 and the magnetic head 2
Is arranged in a hollow box 11 which is sealed so that dust and the like do not enter.

The mechanism for rotating the magnetic disk medium 1 is as follows.
It comprises a disk drive motor 3 such as a spindle motor and a rotary shaft 4 for operatively connecting the disk drive motor 3 and the magnetic disk medium 1. The disk drive motor 3 is disposed outside the box, and the rotating shaft 4 is
It is rotatably supported via a magnetic fluid bearing 10 in a hole 12 provided in one wall.

This magnetic fluid bearing 10 has a sealing function,
An annular case 13 having a dynamic bearing function.
A permanent magnet 15 mounted in an annular groove 14 formed on the inner peripheral surface of the case 13, a magnetic fluid 7 magnetically attracted in a radial gap between the permanent magnet 15 and the rotating shaft 4,
It is composed of In this case, the rotating shaft 4 is a non-magnetic material
Preferably, it may be a magnetic material.

Similarly, a mechanism for driving the magnetic head 2 includes a head driving motor 9 such as a voice coil motor, and the like.
The head drive motor 9 and the magnetic head 2 are constituted by a rotating shaft 4 ′ for operative connection. The head drive motor 9 is disposed outside the box, and the rotating shaft 4 ′ is
Is rotatably supported via a magnetic fluid bearing 10 ′ in a hole 12 provided in the wall of the device.

Since the magnetic fluid bearing 10 'has exactly the same configuration as the magnetic fluid bearing 10 on the magnetic disk medium 1, the same components are denoted by the same reference numerals and description thereof will be omitted.

The magnetic fluid bearings 10, 10 'use magnetic fluids 7, 7' as a medium of a dynamic pressure bearing, and the magnetic fluids 7, 7 'are held by permanent magnets 14.

Therefore, the run-out of the rotary shafts 4 and 4 'can be reduced as compared with the case where the rolling bearing is used, and
High reliability and no noise.

The magnetic fluid bearings 10, 10 '
Since it has a sealing function, that is, a function of a magnetic fluid seal, it is not necessary to use a magnetic fluid seal separately from the bearing.

Therefore, the rotating shafts 4 and 4 'can be shortened, and the magnetic disk device can be made thin.

The magnetic fluid bearings 10, 10 used in this embodiment
Reference numeral 10 'denotes an ordinary sleeve bearing which does not use a step groove, a spiral groove, a herringbone groove, or the like. In order to enhance the load capacity, these sleeves are provided with the outer peripheral surfaces of the rotating shafts 4, 4' or the magnetic fluid bearing. It may be provided on the inner peripheral surface of 10, 10 '.

FIG. 2 shows the internal structure of the disk drive and head drive motors 3 and 9.

Each of the motors 3 and 9 has the same internal configuration. An armature 17 having a coil wound rotatably inserted into an inner hollow housing 16 is connected in series with the armature 17 in the axial direction. And a drive shaft 19 fixed to the armature 17. The drive shaft 19 is rotatably mounted on the housing 16 via the magnetic fluid bearing 20. Supported.

The magnetic fluid bearing 20 has the same configuration as that of the magnetic fluid bearing 10 for the rotating shaft of the magnetic disk medium 1 described above, and has an annular groove 2 provided on the inner peripheral surface of an annular case 21.
An annular permanent magnet 23 is mounted inside the permanent magnet 2.
A magnetic fluid 24 is filled in a gap between the inner circumference 3 and the outer circumference of the drive shaft 19.

The motors 3 and 9 constitute a magnetic fluid bearing 20 by providing a permanent magnet 23 in a bearing portion separately from the permanent magnet 18 which is a driving source of the motors 3 and 9. As shown, the permanent magnet 1 which is the driving source of the motor
8 by directly utilizing the magnetic field created by
0 ′ may be configured.

That is, in this motor, the inner periphery of the permanent magnet 18 is close to the outer periphery of the drive shaft 19, and the outer diameter of the motor is reduced by the space of the permanent magnet 23 of the magnetic fluid bearing 20 of the motor of FIG. I have. A magnetic fluid 24 is filled in a radial gap 25 between the inner periphery of the permanent magnet 18 and the outer periphery of the drive shaft 19.

Further, in this embodiment, the magnetic fluid 24 is also filled in the thrust gap 26 between the permanent magnet 18 and the armature 17, so that it also functions as a thrust bearing. In the illustrated example, a flange 27 is provided integrally with the drive shaft 19 so as to cover the armature surface, and a thrust gap 26 for filling a magnetic fluid is formed between the flange 27 and the permanent magnet 18. When the thrust bearing is used in this way, it is suitable for a vertical motor such as a spindle motor.

As described above, the permanent magnet 18 for driving the motor
Is used as a magnetic force source of the magnetic fluid bearing 20 ', so that the motor can be reduced in size and weight.

According to the magnetic disk drive of the present invention, the motors 3 and 9 using the above-described magnetic fluid bearings 20 and 20 'are used as a drive source and a magnetic head of a mechanism for rotating the magnetic disk medium 1 of the magnetic disk drive. By using the magnetic fluid bearings 10 and 10 ′ as a driving source for driving the magnetic disk medium 1 and a bearing for a mechanism for rotating the magnetic disk medium 1 and a mechanism for driving the magnetic head 2, the shafts of the rotating shafts 4 and 4 ′ are formed. The deflection can be made extremely small and the generation of dust can be prevented, and the reliability of the magnetic disk drive can be improved.

Further, since no rolling bearing is used, a device with lower noise can be realized.

When the magnetic fluid bearing 10 'is used as a mechanism for driving the magnetic head 2, not only the generation of dust is prevented, but also the positioning accuracy and the speed of the magnetic head 2 are improved by reducing the friction. Due to the damping effect of the magnetic fluid 10 ', the vibration of the drive unit is suppressed.

In this embodiment, the case where the motors 3 and 9 are used in a magnetic disk device has been described as an example. However, the present invention is not limited to the magnetic disk device, and various devices such as a drive unit in a clean room, a robot, etc. Of course, it can be applied to

[0042]

[Effects of the Invention] The present invention has the above configuration and operation, and uses a magnetic fluid bearing having a sealing function and a dynamic pressure bearing function as a bearing for a motor drive shaft, thereby improving the rotation accuracy of the rotating shaft. In addition, a motor that does not generate dust can be obtained.

If the magnetic fluid is held by directly utilizing the magnetic field generated by the permanent magnet which is the driving source of the motor as the bearing, the motor can be reduced in size and weight.

This motor is used as a drive source for a mechanism for rotating a magnetic disk of a magnetic disk drive and a drive source for driving a magnetic head, and further, a mechanism for rotating a magnetic disk medium and a bearing for a mechanism for driving a magnetic head. By using a magnetic fluid bearing, the run-out of the rotating shaft can be extremely reduced, dust can be prevented, and the reliability of the magnetic disk drive can be improved. Furthermore, since no rolling bearing is used, a device with lower noise can be realized.

When a magnetic fluid bearing is used as a mechanism for driving the magnetic head, not only generation of dust is prevented, but also positioning accuracy and speed of the magnetic head are improved by lowering friction, and furthermore, damping of the magnetic fluid is performed. The effect suppresses the vibration of the driving unit and improves the reliability.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a schematic configuration of a magnetic disk drive according to an embodiment of the present invention.

FIG. 2 is a half sectional view of the motor of FIG. 1;

FIG. 3 is a half sectional view of another embodiment of the motor of FIG. 1;

FIG. 4 is a perspective view showing a schematic configuration of a conventional magnetic disk drive.

FIG. 5 is a half sectional view of the motor of FIG. 4;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Magnetic disk medium 2 Magnetic head 3,9 Motor 4,4 'Rotating shaft 7,7' Magnetic fluid 10,10 'Magnetic fluid bearing 11 Box 12 Hole 13 Case 14 Annular groove 15 Permanent magnet 16 Housing 17 Armature 18 Permanent Magnet 19 Drive shaft 20, 20 'Magnetic fluid bearing 21 Case 22 Annular groove 23 Permanent magnet 24 Magnetic fluid 25 Radial groove 26 Thrust direction groove 27 Flange

Claims (3)

(57) [Scope of request for utility model registration] 1. An armature, a stator having a permanent magnet disposed so as to surround the armature, a drive shaft provided integrally with the armature, and a bearing for rotatably pointing the drive shaft. When, in the motor provided with the, Rutotomoni using a magnetic fluid bearing as the bearing, the magnetic flow
The above-mentioned stator is used as a magnetic force source for holding a magnetic fluid of a body bearing.
A motor using the magnetic field created by a permanent magnet . 2. The magnetic fluid of the magnetic fluid bearing is provided between the stator and the drive.
And-radial clearance between the shaft, the armature and stator
2. The gap between the thrust direction and the gap in the thrust direction is filled.
Motor. 3. A magnetic disk medium, a magnetic head,
A mechanism for rotating the magnetic disk medium and the magnetic head;
And a mechanism for driving the magnetic disk drive.
Oite, mechanisms and magnetic heads for rotating said magnetic disk medium
Claim 1 or Claim 2 as a drive source of a mechanism for driving a drive.
A motor according to any one of the above.
Magnetic disk drive.