JPH05151723A - Disk device actuator - Google Patents

Abstract

PURPOSE:To reduce the size of the device and to provide a thinner configuration keeping a good vibration characteristic by dividing an actuator shaft(AS) into a first and a second AS, making one of the AS's tip a smaller radius section and providing a radial bearing. CONSTITUTION:The first AS 52 is vertically installed on a base 51a of a housing 51 and second AS 53 is vertically installed on a top surface 51b concentrically with the AS52. On the AS52, a first thrust bearing (SB) 54 is provided so that its inner race and on the AS53, a second SB55 is provided so that its inner races freely bit. A smaller radius section 52a is formed at the tip section of the AS52 and the inner races of a radial bearing (RB) 56 are freely fitted. Near the opening of an actuator block(AB) 57, large opening sections 58a and 58b are formed and a through-hole 58 is provided on which a small radius section 58c is formed facing the small radius section 52a of the AS52 in the middle section. Outer races of the SB54 and 55 are force-fitted into the large opening sections 58a and 58b, respectively and the outer races of the RB56 are freely fitted into the small radius section so that the AB57 freely rotates against the AS52 and 53.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is rotatably mounted on a base of a housing, has a head attached to a rotary end thereof, and swings with respect to a disk driven to rotate with respect to the base of the housing. The present invention relates to an actuator of a disk device that moves the head to a desired track on the disk.

In recent years, with the improvement of the areal recording density by improving the characteristics of the head and the recording medium in the disk device, there is a demand for downsizing and thinning of the disk device.

[0003]

2. Description of the Related Art Next, a conventional example will be described with reference to the drawings.
FIG. 4 is a main part configuration diagram of an actuator of a magnetic disk device disclosed in Japanese Patent Laid-Open No. 3-168980.

In the figure, reference numeral 1 is a housing for sealing the inside of the apparatus. Base 1a and top surface 1 of this housing 1
The actuator shaft 2 is attached to b by using screws 3 and 4. Small diameter portions 2a and 2b are formed at both ends of the actuator shaft 2, and a large diameter portion 2c having a diameter larger than those of the small diameter portions 2a and 2b is formed at an intermediate portion. The inner ring of the first thrust bearing 5 is loosely fitted to the small diameter portion 2a of the actuator shaft 2, and the inner ring of the second thrust bearing 6 is loosely fitted to the small diameter portion 2b. The inner ring of the radial bearing 7 is loosely fitted in the large diameter portion 2c.

A through hole 8a into which the actuator shaft 2 is fitted is formed in the central portion of 8, and a head arm extending in the direction of the recording surface of the rotationally driven magnetic disk 10 is formed at one rotating end portion. 9 is the formed actuator block. A magnetic head (not shown) is provided at the tip of the head arm 9 to read / write data from / to the recording surface of the magnetic disk 10 via a head support mechanism.

Large-diameter portions 8b and 8c facing the small-diameter portions 2a and 2b of the actuator shaft 2 are formed at both ends of the through-hole 8a, and the large-diameter portion 2c of the actuator shaft 2 is formed at an intermediate portion. Opposing small diameter portions 8d are formed.

The outer ring is the actuator block 8
Of the through hole 8a of the actuator shaft 2, the inner ring loosely fits into the large diameter portion 2c of the actuator shaft 2, and the outer ring of the through hole 8 of the actuator block 8.
The first thrust bearing 5 and the second thrust bearing 6 in which the inner ring is press-fitted into the large-diameter portions 8b and 8c of a and the inner ring is loosely fitted in the small-diameter portions 2a and 2c of the actuator shaft 2 cause the actuator block 8 to move. Is rotatably attached to.

Further, on the base 1a on the other rotating portion side of the actuator block 8, there are arranged yokes 11 facing each other.
12 and a magnet 1 attached to the opposing surfaces of these yokes
A magnetic circuit 15 composed of 3 and 14 is provided.

A coil 16 arranged in the magnetic gap G of the magnetic circuit 15 is provided at the other rotating end of the actuator block 8. Next, the preload mechanism of the first and second thrust bearings 5 and 6 will be described. Reference numeral 17 is a first spacer that comes into contact with the inner ring of the first thrust bearing 5, and 18 is a second spacer that comes into contact with the inner ring of the second thrust bearing 6. Then, in the space between the first spacer 17 and the top surface 1b of the housing 1, the two stacked disc springs 19 and 20 are inserted in a compressed state, and the inner ring of the first thrust bearing 5 is inserted. It is pressed in the axial direction of the actuator shaft 2. This pressing force is applied to the first spacer 17, the ball of the first thrust bearing 5, the outer ring, the actuator block 8, the outer ring of the second thrust bearing 6, the ball, the inner ring of the second thrust bearing 6, and the second spacer. Through 18,
It is transmitted to the base 1a of the housing 1 and preloads the rattling of the first and second thrust bearings 5 and 6.

Next, the preload mechanism of the radial bearing 7 will be described. A hole 2d is formed in the large diameter portion 2c of the actuator shaft 2. One end is in contact with the bottom of the hole 2d, and the other end is provided with a spring 21 for urging the inner ring of the radial bearing 7 in the radial direction of the actuator shaft 2 via the ball 20. Due to the bias of the spring 21, the radial bearing 7 and the actuator block 8 are deviated, and thermal off-track can be reduced.

Next, the operation of the above configuration will be described. When a control unit (not shown) supplies a current to the coil 16, a thrust force is generated in the coil 16 to rotate (swing) the actuator block 8 about the actuator shaft 2. When the actuator block 8 rotates, a magnetic head (not shown) moves to a desired track on the magnetic disk 10, and data reading / writing is performed.

[0012]

However, in the actuator configured as described above, the diameter of the inner ring of the radial bearing 7 is larger than the diameters of the inner rings of the first and second thrust bearings 5 and 6, and the radial bearing 7 has a larger diameter. If the diameter of the outer ring is smaller than the diameter of the outer ring of the first and second thrust bearings 5 and 6, the outer ring cannot be assembled.

On the other hand, when the disk device having such a structure is made smaller and thinner, it is conceivable to reduce the outer diameter (horizontal width direction) of the actuator block 8. However, increasing the diameter of the inner ring of the radial bearing and reducing the diameter of the outer ring have a structural limit of the bearing, so if the outer diameter of the actuator block 8 is reduced,
There is no choice but to reduce the diameter of the actuator shaft 2.

When the diameter of the actuator shaft is made small, the vibration rigidity becomes low and the resonance frequency of each mode (lateral vibration / torsional vibration) becomes low. As a result, there is a problem that the vibration characteristics of the actuator system including the actuator block 8, the head arm 9, the coil 16 and the like deteriorate, and the head cannot be positioned stably with respect to the disk.

The present invention has been made in view of the above problems, and an object of the present invention is to provide an actuator for a disk device which can be downsized and thinned while maintaining good vibration characteristics. It is in.

[0016]

FIG. 1 is a principle view of the invention described in claim 1. In the figure, 31 is a housing 32
It is a disk that is rotationally driven with respect to the base 33 of the.
34 is the base 33 of the housing 32,
Is a first actuator shaft standing upright toward the top surface 35 of the housing 31 and is a second actuator shaft standing upright toward the base 32 coaxially with the first actuator 34 on the top surface 35 of the housing 31. is there.

The first actuator shaft 34 includes:
A first thrust bearing 37 having an inner ring loosely fitted to the first actuator shaft 34 and a second thrust bearing 3 having an inner ring loosely fitted to the second actuator shaft 36 are provided on the second actuator shaft 36.
8 are provided.

Reference numeral 39 designates large diameter portions 40a and 40 near the opening.
b, a through hole 40 having a small diameter portion 40c formed in an intermediate portion is formed, and the large diameter portions 40a and 40b and the small diameter portion 4 of the through hole 40 are formed.
The outer ring of the first thrust bearing 37 and the second thrust bearing 38 is in contact with the step portion formed at the boundary with 0c, and the head arm 41 is formed at the rotating end portion of the actuator block.

Either one of the first actuator shaft 34 and the second actuator shaft 36 (the first actuator shaft 34 in the principle diagram).
A small diameter portion 34a is formed on the tip end side, and the small diameter portion 3a
A hole 42 is formed on the circumferential surface of 4a.

Reference numeral 43 designates a radial in which the inner ring is loosely fitted in the small diameter portion 34a of the shaft (the first actuator shaft 34 in the present principle view) provided with the hole 42, and the outer ring is also loosely fitted in the through hole 40 of the actuator block 39. It is a bearing.

Reference numeral 45 denotes a first elastic member which is disposed in the hole 42 and presses the inner ring of the radial bearing 43 in the radial direction of the actuator shaft 34 to preload the radial bearing 43. One end of 46 is pressed against the housing 31. The other end has the first and second thrust bearings 37,
One of the bearings 38 (in the principle diagram, the second bearing
The outer ring of the thrust bearing 38) is pressed toward the outer ring of the other bearing (the first thrust bearing 37 in the present principle diagram), and the first and second thrust bearings 3
This is a second elastic body that preloads 7,38.

[0022]

In the actuator of the disk device of the present invention, the actuator shaft is divided into the first actuator shaft 34 and the second actuator shaft 3.
6, and the radial bearing 43 is attached to the small diameter portion 34a of the first actuator shaft 34, so that the diameter of the inner ring of the radial bearing 34 is the diameter of the inner rings of the first and second thrust bearings 37, 38. Can be smaller than. Therefore, even if the outer diameter of the actuator block 39 is reduced, the first and second
The diameters of the actuator shafts 34, 36 can be set large, and the disk device can be made smaller and thinner while maintaining good vibration characteristics.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described with reference to the drawings. FIG. 2 is a main part configuration diagram illustrating an embodiment of the present invention, and FIG. 3 is an overall cross-sectional configuration diagram of a magnetic disk device provided with the actuator shown in FIG.

In these figures, 51 is a housing for sealing the inside of the apparatus. A first actuator shaft 52 is erected on the base 51a of the housing 51 toward the top surface by shrink fitting. On the other hand, a second actuator shaft 53 is erected on the top surface 51b of the housing 51 coaxially with the first actuator shaft 52 by shrink fit.

On the first actuator shaft 52,
The first actuator shaft 52 is provided with a first thrust bearing 54 in which the inner ring is loosely fitted.
In addition, the second actuator shaft 53 has the second
A second thrust bearing 55 is provided on the actuator shaft 53 of which the inner ring is loosely fitted.

A small diameter portion 52a is formed at the tip of the first actuator shaft 52, and the small diameter portion 52a is formed.
The inner ring of the radial bearing 56 is loosely fitted in the.
Reference numeral 57 is an actuator block in which large-diameter portions 58a and 58b are formed in the vicinity of the opening, and a through-hole 58 is formed in the middle portion of which a small-diameter portion 58c that faces the small-diameter portion 52a of the first actuator shaft 52 is formed.

The outer ring of the first thrust bearing 54 is press-fitted into the large diameter portion 58a of the through hole 58, the outer ring of the second thrust bearing 55 is press fit into the large diameter portion 58b, and the radial bearing 56 is fitted into the small diameter portion. The outer ring of the actuator block 57 is loosely fitted, and the actuator block 57 is connected to the first actuator shaft 52 and the second actuator shaft 5 through the first thrust bearing 54, the second thrust bearing 55 and the radial bearing 56.
It is rotatable with respect to 3. At this time, the through hole 58
The outer rings of the first thrust bearing 54 and the second thrust bearing 55 are in contact with the stepped portion formed at the boundary between the large diameter portions 58a and 58b and the small diameter portion 58c.
A head arm 59 is formed at one rotating end of the actuator block 57. Head arm 59
The head 51 is attached to the tip of the base 51 through the head support mechanism 61.
A magnetic head 62 that is arranged in a layer a and reads / writes data from / to the recording surface of the magnetic disk 60 that is rotationally driven (for example, 3600 rpm) by a disk drive motor (not shown) is provided.

A hole 63 is formed on the circumferential surface of the small diameter portion 52a of the first actuator shaft 52.
First, the inner ring of the radial bearing 56 is pressed in the radial direction of the first actuator shaft 52 via the ball 64 to preload the radial bearing 56.
A spring 65 as an elastic member is provided.

Reference numeral 70 is a first spacer that abuts on the inner ring of the first thrust bearing 54, and 71 is a second spacer that abuts on the inner ring of the second thrust bearing 55. Then, in the space between the second spacer 72 and the top surface 1b of the housing 51, two disc springs 73, 74 laminated as a second elastic member are inserted in a compressed state, The inner ring of the thrust bearing 55 is pressed in the axial direction of the actuator shaft. This pressing force is
Via the second spacer 72, the ball of the second thrust bearing 55, the outer ring, the actuator block 57, the outer ring of the first thrust bearing 54, the ball, the inner ring of the first thrust bearing 54, and the first spacer 71, The pressure is transmitted to the base 51a of the housing 51 and preloads the rattling of the first and second thrust bearings 54 and 55.

Further, the base 51a on the other rotating portion side of the actuator block 57 includes an upper yoke 81 and a lower yoke 82 which are arranged to face each other, and magnets 83 and 84 which are attached to the facing surfaces of these yokes 81 and 82. A configured magnetic circuit 85 is provided.

At the other rotating end of the actuator block 57, the magnetic gap G of the magnetic circuit 85 is
A coil 86 to be arranged is provided. Next, the operation of the above configuration will be described. When a control unit (not shown) supplies a current to the coil 86, a thrust is generated in the coil 86 to rotate (swing) the actuator block 57 about the first and second actuator shafts 52 and 53. When the actuator block 57 rotates, the magnetic head 62 moves to a desired track on the magnetic disk 60, and data reading / writing is performed on the magnetic disk 60.

According to the above construction, the actuator shaft is divided into the first actuator shaft 52 and the second actuator shaft 52.
Actuator shaft 53, and the radial bearing 56 is attached to the small diameter portion 52a of the first actuator shaft 52, so that the diameter of the inner ring of the radial bearing 56 can be made smaller than that of the first and second thrust bearings 54, 55. It can be made smaller than the diameter of the inner ring. Therefore, even if the outer diameter of the actuator block 57 is made small, the diameters of the first and second actuator shafts 52, 53 can be set large, and the disk device can be made compact and thin while maintaining good vibration characteristics. It will be possible.

The present embodiment is not limited to the above construction. The radial bearing 56 may be provided with a small diameter portion at the tip end portion of the second actuator shaft 53 and may be arranged in this small diameter portion. Further, the disc springs 53, 54 for preloading in the thrust direction are provided on the top surface 51b side of the housing 51, but may be provided on the base 51a side.

Further, although the first and second actuator shafts 52, 53 are attached to the housing 51 by shrink fit, the present invention is not limited to this, and may be screwed or the like.

Further, although the above-mentioned embodiment is a magnetic disk device, the present invention is not limited to this, and may be, for example, an optical disk device.

[0036]

As described above, according to the present invention, the actuator shaft is divided, the tip end of one actuator shaft is made into a small diameter portion, and the radial bearing is provided in this small diameter portion. It is possible to realize an actuator for a disk device that can be made smaller and thinner while maintaining the above.

[Brief description of drawings]

FIG. 1 is a principle diagram of the invention according to claim 1;

FIG. 2 is a configuration diagram of main parts for explaining an embodiment of the present invention.

FIG. 3 is an overall cross-sectional configuration diagram of a magnetic disk device provided with the actuator shown in FIG.

FIG. 4 is a main part configuration diagram of an actuator of the magnetic disk device disclosed in Japanese Patent Laid-Open No. 3-168980.

[Explanation of symbols]

 31 Disc 32 Housing 33 Base 34 First Actuator Shaft 35 Top Surface 36 Second Actuator Shaft 37 First Thrust Bearing 38 Second Thrust Bearing 39 Actuator Block 40 Through Holes 40a, 40b Large Diameter Portion 40c Small Diameter Portion 41 Head Arm 42 hole 43 radial bearing 45 first elastic member 46 second elastic member

Claims (2)

[Claims] 1. A disk () which is rotatably provided on a base (33) of a housing (32), has a head attached to a rotary end thereof, and is rotationally driven with respect to the base (33) of the housing (32). 31) In an actuator of a disk device that swings with respect to 31) and moves the head to a desired track of the disk (31), stands on a base (33) of a housing (32) toward a top surface (35). First actuator shaft (3
4) and a second actuator shaft (2) that is erected on the top surface (35) of the housing (32) coaxially with the first actuator shaft (34) toward the base (33).
6), a first thrust bearing (37) having an inner ring loosely fitted to the first actuator shaft (34), and a second thrust bearing (37) having an inner ring loosely fitted to the second actuator shaft (36). 38) and a through hole (40) having a large diameter portion (40a, 40b) in the vicinity of the opening and a small diameter portion (40c) in the middle, and the large diameter portion (40a) of the through hole (40). The outer ring of the first thrust bearing (37) and the second thrust bearing (38) come into contact with the stepped portion formed at the boundary between the small diameter portion (40c) and the small diameter portion (40c), and the rotation end portion has The actuator block (3 having the head arm (41) formed therein
9), and a small diameter portion (34a) is formed on the tip end side of either one of the first actuator shaft (34) and the second actuator shaft (36).
Radial bearing in which the inner ring is loosely fitted in the hole (42) formed in the circumferential surface of 4a) and the small diameter portion (34a), and the outer ring is also loosely fitted in the through hole (40) of the actuator block (39). (43) and a first elastic member (4) disposed in the hole (42) for pressing the inner ring of the radial bearing (43) in the radial direction to preload the radial bearing (43).
5) and one end presses the housing (32) and the other end presses the outer ring of one of the first and second thrust bearings (34, 38) toward the outer ring of the other bearing. The first and second thrust bearings (3
And a second elastic body (46) for preloading (4, 38), and an actuator for a disk device. 2. The first actuator shaft (3
4) and the second actuator shaft (36)
The actuator of the disk drive according to claim 1, wherein the actuator is attached to the housing (32) by shrink fit.