JPH11215791A - Rotation drive - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce runout in a radial direction while an object is rotating by disposing a magnetic circuit constituted of a plurality of magnets and a plurality of coils between two air bearings. SOLUTION: A rotor 2 and a stator 12, and a plate 3 and the stator 12 are disposed so as to have a slight clearance at a boundary part. By having air supplied from the outside flow into respective boundary parts from the stator 12, an air membrane is formed to attain the function of a bearing. The two air bearings are disposed at a motor housing 13, and a motor part 4 is disposed between the two air bearings 1. The supporting shaft 16 of the motor part 4 is integrally-fixed through another shaft 7, and a rotor yoke 6 formed out of magnetic substance and a plurality of magnets 5 are fixed to a support shaft 16. The disc-shaped scale 11 of an encoder is integrally formed at the end part of one air bearing 1, and the angle of a rotating part including the two air bearings 1 and the motor part 4 is measured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary drive device used in various production devices such as a hard disk inspection device, a servo signal recording device, and an optical disk test device.

[0002]

2. Description of the Related Art Conventionally, as this kind of rotary drive device, there has been known a spindle motor suitably used for a disk test device or the like.

FIG. 5 shows a configuration of a spindle motor, and FIG. 6 shows a configuration of a rotating portion thereof. The air bearing 101 is the rotor 1
02, a stator 112, and two plates 103. The rotor 102 and the stator 112 are disposed with a slight gap at the boundary between the rotor 102 and the stator 112.
Similarly, the stator 3 and the stator 112 are disposed with a slight gap at the boundary. The air supplied from outside flows from the stator 112 into each of the boundary portions to form an air film, thereby achieving a bearing function. Plate 10
3, a support shaft 116 of the motor 104 is integrally fixed, and the support shaft 116 has a rotor yoke 10 made of a magnetic material.
6 and a plurality of magnets 105 are fixed. Support shaft 116
Is integrally provided with a disk-shaped scale 111 of an encoder for measuring the angle of the rotating portion including the support shaft 116. 108 is a motor coil, 109 is a core (magnetic core),
Reference numeral 113 denotes a motor housing, and 117 denotes a table on which a disk is mounted.

[0004]

However, in the above-mentioned conventional example, there is a drawback that radial deflection occurs during rotation of the object due to insufficient rigidity of the air bearing for supporting the rotation. SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems in the conventional example, and has as its object to reduce radial deflection during rotation of an object.

[0005]

Therefore, in the rotary driving device according to the present invention, two air bearings are provided, and a plurality of magnets and a plurality of coils are provided between the two air bearings. This problem is solved by disposing a magnetic circuit.

[0006]

Embodiment 1 Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a configuration of a spindle motor according to an embodiment of the present invention, and FIG. 2 shows a configuration of a rotating portion thereof. The air bearing 1 includes a rotor 2, a stator 12, and two plates 3 (3
a, 3b). The rotor 2 and the stator 12 are disposed so as to have a small gap at the boundary, and the plate 3 and the stator 12 are also disposed so as to have a small gap at the boundary. An air film is formed by flowing air supplied from the outside from the stator 12 into each of the above-mentioned boundaries, thereby achieving a bearing function. The two air bearings 1 are provided in the motor housing 13, and the motor unit 4 is provided between the two air bearings 1. A support shaft 16 of the motor unit 4 is integrally fixed to the plate 3 via another shaft 7, and a rotor yoke 6 made of a magnetic material and a plurality of magnets 5 are fixed to the support shaft 16. At one end of the air bearing 1 (lower side in the drawing), a disk-shaped scale 11 of an encoder is integrally provided.
The angle of the rotating part including the air bearing 1 and the motor part 4 is measured. Reference numeral 8 denotes a motor coil, 9 denotes a core (magnetic core), 13 denotes a motor housing, and 117 denotes a table on which a disk is placed.

[0007]

Embodiment 2 FIG. 3 shows a configuration of a spindle motor according to another embodiment of the present invention, and FIG. 4 shows a configuration of a rotating portion thereof. The air bearing includes a rotor 23 (23a or 23b), a stator 22, and one plate 21 (21a or 21b). The rotor 23 and the stator 22 are disposed with a slight gap at the boundary between the rotor 23 and the stator 22.
Similarly, the stator 22 is also provided with a slight gap at the boundary. Air supplied from outside is supplied to the stator 2
The air film is formed by flowing into each of the boundary portions from 2 to achieve the function of the bearing. Two of these air bearings,
The motor unit is disposed on the motor housing 28, and a motor unit is disposed between the two air bearings. At one end of the rotor 23, a support shaft 33 of a motor unit is integrally formed. The support shaft 33 includes a rotor yoke 25 made of a magnetic material and a plurality of magnets 24.
Has been fixed. Plate 21b of one air bearing
A disk-shaped scale 27 of an encoder is integrally provided at an end of the rotary shaft, and measures an angle of a rotating unit including the two air bearing motor units. Reference numeral 32 denotes a table on which a disk is placed.

[0008]

As described in detail above, the rotary drive device according to the present invention has two air bearings and a motor unit between them, thereby doubling the rigidity of the air bearing that supports rotation. It has become possible to sufficiently suppress the radial deflection during rotation of the object.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a spindle motor according to one embodiment of the present invention.

FIG. 2 is a diagram illustrating a configuration of a rotating unit of the spindle motor of FIG. 1;

FIG. 3 is a configuration diagram of a spindle motor according to another embodiment of the present invention.

FIG. 4 is a diagram illustrating a configuration of a rotating unit of the spindle motor of FIG. 3;

FIG. 5 is a configuration diagram of a conventional spindle motor.

FIG. 6 is a diagram illustrating a configuration of a rotating unit of the spindle motor in FIG. 5;

[Explanation of symbols]

1: air bearing, 2, 23 (23a, 23b): rotor, 3 (3a, 3b), 21 (21a, 21b): plate, 4: motor part, 5: magnet, 6: rotor yoke,
7: another axis, 8: motor coil, 9: core (magnetic core), 1
2,22: Stator, 13,28: Motor housing,
16, 33: spindle, 17, 32: table.

Claims (1)

[Claims] In a rotary drive device using a bearing using a fluid as a medium, an electromagnetic motor, and an encoder, two bearings using the fluid as a medium are provided, and two bearings using the fluid as a medium are provided. The motor is arranged between bearings, and the disk-shaped scale for the encoder is arranged on a rotating portion of the bearing opposite to the motor with one of the bearings using the fluid as a medium. And a rotation drive device.