JPH04302873A - Voice-coil motor for magnetic disk device - Google Patents

Abstract

PURPOSE:To simplify the structure of a voice-coil motor for driving a magnetic head of a magnetic disk device and to simplify its assembly. CONSTITUTION:One end of a shaft 32 for mounting freely rotatably a voice-coil supporting frame 50 is fixed to a yoke 22 on the side of a pedestal of the voice- coil motor. A yoke 24 on the opposite side is positioned to the yoke 22 on the side of the pedestal by a side yoke 26 which is integral with the yoke 24. A screw 44 is inserted into a small hole 42 of this opposite side yoke 24, and this screw 44 is tightened in a screw hole 40 formed on the other end of the shaft 32.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a voice coil motor for a magnetic disk device that moves a magnetic head along a recording surface of a magnetic disk.

0002

2. Description of the Related Art Generally, in small magnetic disk drives used as hard disk drives for personal computers or word processors, a carriage mechanism has been developed in which a voice coil motor swings a magnetic head in an arc along the recording surface of the magnetic disk. There is.

FIG. 4 schematically shows an example of this type of carriage mechanism.

[0004] This carriage mechanism includes a voice coil motor (hereinafter also referred to as VCM in this specification) 1 and a VCM.
Swing arm 2 swung in the direction of arrow A by CM1
A suspension 2a is attached to this swing arm 2.
A magnetic head 3 is mounted via the magnetic head 3 .

The VCM 1 that moves the magnetic head 3 also includes a pair of flat yokes 7, 7 fixed in parallel by a pair of supports 6, 6, and a flat permanent yoke fixed to the inner surfaces of these yokes 7, 7. It includes magnets 8, 8. These magnets 7a,
Voice coil 8 that forms a magnetic field that intersects the magnetic flux between 7a
is pivotally connected to the shaft 9 via a support frame integral with the swing arm 2. The upper end of this shaft 9 is pressed against and supported by the upper yoke 7 by a support member 9a shaped like a leaf spring.

[0006] This carriage mechanism is compactly mounted on the base of a magnetic disk device together with a spindle motor 5 for driving a magnetic disk 4.

When the magnetic disk device is not in operation, the magnetic head 3 is in contact with the magnetic disk 4 at a contact stop start (CSS) area provided on the inner circumference of the recording surface of the magnetic disk 4, and the magnetic head 3 is in contact with the magnetic disk 4 at this position. Retained. When the magnetic disk 4 is rotated at high speed in the direction of arrow B by the spindle motor 5, the wind pressure causes the magnetic head 3 to rotate.
floats up and can be moved to the required position by VCM1. The holding position of the magnetic head 3 is determined by the inner stopper, and even if the magnetic head 3 runs out of control for some reason, the outer stopper prevents it from falling off the magnetic disk.

[0008]

The VCM 1 of the carriage mechanism described above is directly attached to a base after a voice coil support frame integral with the swing arm 2 is attached to the shaft 9. Further, the pair of yokes 7, 7 are also attached to the base separately from the shaft 9. Therefore, many steps are required to attach the carriage mechanism. Furthermore, since the upper end of the shaft 9 is supported by a support member 9a shaped like a leaf spring, a large number of parts are required.

The present invention has been made in view of the above, and an object of the present invention is to provide a voice coil motor that has a simple structure and is easy to assemble into a magnetic disk drive.

0010

[Means for Solving the Problems] A voice coil motor for a magnetic disk device according to the present invention includes a base-side yoke of the voice coil motor formed in a flat plate shape and mounted on a base of the magnetic disk device, and a A shaft having one end fixed to the side yoke and the other end protruding from the base side yoke, a voice coil support frame rotatably attached to this shaft, supported by the base side yoke, and this It is characterized by comprising an opposing yoke that sandwiches the support frame together with the base-side yoke, and a coupling means that firmly couples the opposing yoke to the other end of the shaft.

[0011]

[Operation] In this voice coil motor, one end of the shaft is fixed to the base side yoke, and a voice coil support frame is attached to this shaft. Thereafter, the opposing yoke is firmly coupled to the other end of the shaft. As a result, the base side yoke and the opposing side yoke are placed on both sides of the voice coil support frame,
A voice coil motor assembly is formed by integrally connecting these two yokes with a shaft.

0012

Embodiment FIG. 2 shows an entire magnetic disk drive 10 using a voice coil motor according to an embodiment of the present invention.

This magnetic disk device 10 has a base 12 that also serves as a housing, and a spindle motor 15 that drives a magnetic disk, commonly known as a hard disk 14, and a carriage mechanism that drives a magnetic head 18 via a swing arm 16 and a suspension 17. 20 are fixed and sealed with a cover 13. This carriage mechanism 20
The magnetic head 18 includes a VCM and is mounted on the tips of a swing arm 16 and a suspension 17, and swings in an arc between the inner and outer circumferential sides of the magnetic disk 14 along the recording surface of the magnetic disk 14.

As shown in FIG. 1, the VCM 21 that swings the swing arm 16 of the carriage mechanism 20 is mounted on the base 12
(FIG. 2) has a flat base-side yoke 22 mounted on the base-side yoke 22, and an opposing-side yoke 24 disposed opposite to this base-side yoke 22. This opposing side yoke 24 has a substantially fan-shaped shape, and side yokes 26, 26 extend from both side edges thereof toward the base side yoke 22. Positioning protrusions 28, 2 are provided at the lower ends of these side yokes 26, 26.
8 are formed, and positioning holes 30, 30 are formed in the base side yoke 22 at positions corresponding to these positioning protrusions 28, 28. These opposing yokes 24
The base side yoke 22 can be formed at extremely low cost by press molding.

The upper and lower yokes 22 and 24 thus formed are integrally connected by a shaft 32. This shaft 32 has a small diameter lower end portion 34 and a flange portion 36.
, a shaft portion 38 , and a screw hole 40 formed in the upper end surface of the shaft portion 38 . The lower end portion 34 of the shaft 32 is inserted into a mounting hole 44 formed in the base side yoke 22, and is disposed perpendicularly to the base side yoke 22. This lower end portion 34 is formed to a dimension that projects from the lower surface of the base-side yoke 22, and is preferably press-fitted into the attachment hole 44 or firmly fixed using an adhesive. Further, a screw 44 is inserted into the screw hole 40 of the shaft 32 through a small hole 42 of the upper yoke 24.
is screwed in. In order to prevent the head of the screw 44 from protruding from the upper surface of the opposing yoke 24 when the screw 44 is screwed into the screw hole 40, it is desirable that the circumference of the small hole 42 be recessed.

The magnet 46 of the VCM is fixed to the back surface of the opposing yoke 24 with adhesive, for example. This magnet 46 has permanent magnets 46a and 46b that form magnetic fluxes in opposite directions. A magnetic flux deriving portion 47 protrudes from the left outer peripheral portion of the permanent magnet 46a, and this magnetic flux deriving portion 47 protrudes to the outside of a moving path of a voice coil, which will be described later.

Furthermore, the base side yoke 22 and the opposing side yoke 2
The voice coil 48 that swings between the swing arm 16 and the swing arm 16 is attached to a support frame 50 that is integrally formed with the swing arm 16. This support frame 50 is attached to the shaft portion 38 of the shaft 32 via a ball bearing 52, and
and the base side yoke 22. As shown in FIG. 3, a magnetic head 18 mounted on a swing arm 16 via a suspension 17 swings along the recording surface of the magnetic disk 14 as shown in FIG. Note that the magnetic disk device 10 of this embodiment has two magnetic disks 14 arranged coaxially, and for this reason, three swing arms 16 are provided on the support frame 50, and two swing arms 16 are provided on the central swing arm 16. A magnetic head 18 is mounted.

As shown in FIG. 1, a rectangular locking member 54 made of a magnetic material is provided at the free end of the support frame 50, that is, at the end remote from the ball bearing 52. As shown in FIG. This locking member 54 is attracted to the magnetic flux deriving portion 47 when the magnetic disk device 10 is inactive and retreats to the contact stop start (CSS) area 14a (FIG. 2) on the inner circumferential side of the magnetic disk 14. The magnetic head 18 and therefore the support frame 50 are locked, and the magnetic head 18 is locked.
protect from external vibrations and shocks.

In order to maintain a constant locking force between the lock member 54 and the magnetic flux leakage portion 47, a contact portion 56 is provided that protrudes from the side of the support frame 50, and a contact portion 56 is provided inside the side yoke 26 through an insertion hole 58. A circumferential stopper member 60 is attached.

The inner stopper member 60 is attached to the side yoke 2.
6 and the side yoke 26.
a truncated conical locking portion 66 that locks on the outer surface of the insertion hole 58;
It has a shaft portion 64 disposed within. The inner stopper member 60 is made of an elastic material such as resin, and the tip of its head 62 is curved. Further, a reduced diameter portion 68 is formed in the shaft portion 64 at a portion adjacent to the locking portion 66 . By providing the reduced diameter portion 68 adjacent to the locking portion 66, the material of the locking portion 66 flows into the reduced diameter portion 68 when the inner stopper member 60 is inserted into the insertion hole 58. , the shaft portion 64 can be easily inserted.

Furthermore, openings 78 and 80 are formed in the opposing yoke 24 and the base yoke 22. The outer circumferential stopper member 70 is inserted through these openings 78 and 80.

The outer stopper member 70 has a sleeve 72 made of an elastic material such as resin and a sleeve 74 made of a rigid material such as metal that is fitted inside the sleeve 72 and is firmly fixed to the base 12 by a fixing screw 76. be done. When the magnetic head 18 approaches the outer periphery of the magnetic disk 14 as shown in FIG.
As shown in FIG.
comes into contact with this outer peripheral side stopper member 70.

Carriage mechanism 2 having the above VCM 21
0 is assembled as follows.

First, the shaft 32 is fixed to the base side yoke 22, and the shaft portion 38 of this shaft 32 is attached to the base side yoke 22.
It is placed in such a way that it protrudes perpendicularly from 2. A support frame 50 formed integrally with the swing arm 16 is attached to a ball bearing 5.
2 to the shaft portion 38 of the shaft 32. This state is shown in FIG.

On the side yoke 26 of the opposing yoke 24,
The inner stopper member 60 is inserted through the insertion hole 58 shown in FIG.
Attach. Next, the positioning protrusions 28, 28 protruding from the side yokes 26, 26 are inserted into the positioning holes 30, 30 of the base side yoke 22, and these opposing yokes 2
4 and the base side yoke 22 are positioned, and the screw 44 is inserted into the small hole 42 of the opposing side yoke 24 and screwed into the screw hole 40 of the shaft 32. As a result, the base side yoke 22
An assembly in which the opposite yoke 22 is integrally fixed is completed. This completed assembly is then assembled onto the base 12. To assemble the base 12 to the base 12, a hole is made in advance at a predetermined position of the base 12 to fit into the lower end 34 of the shaft 32, and the shaft 32 is inserted into this hole so that the shaft 32 protrudes from the lower surface of the base side yoke 22. It is desirable to fit the lower end portion 34 of the. This allows accurate positioning with respect to the spindle motor 15. Finally, the outer stopper member 70 is inserted through the openings 78, 80 of the base side yoke 22 and the opposing side yoke 24 and fixed to the base with the screws 76, thereby completing the installation of the carriage mechanism 20.

Carriage mechanism 20 including this VCM 21
According to the method, the lower end portion 34 of the shaft 32 is
2 can be fixed in advance, making it easy to handle during assembly. Furthermore, since the opposing yoke 24 is attached to a predetermined position on the base side yoke 22 by means of a side yoke 26 integrated therewith, and is fixed to the upper end of the shaft 32 with a screw 44, assembly onto the base 12 is easy. It can be assembled in advance as a subassembly, making attachment to the base 12 easy. The shaft 32 is firmly supported at both ends by the base side yoke 22 and the opposing side yoke 24, and the support frame 50 and swing arm 16 can swing stably on the shaft portion 38 of the shaft 32. Can be done.

[0027]

[Effects of the Invention] As is clear from the above, according to the present invention,
A voice coil motor that is simple in structure, highly reliable in operation, and easy to assemble into a magnetic disk device can be formed at low cost.

[Brief explanation of drawings]

FIG. 1 is an exploded schematic perspective view of a voice coil motor for a magnetic disk device according to an embodiment of the present invention.

FIG. 2 is a perspective view showing the inside of a magnetic disk device incorporating the voice coil motor of FIG. 1;

FIG. 3 is a perspective view showing the voice coil motor of FIG. 1 in a partially assembled state.

FIG. 4 is a schematic perspective view of a conventional carriage mechanism.

[Explanation of symbols]

10...Magnetic disk device, 14...Magnetic disk, 18...
Magnetic head, 20... Carriage mechanism, 21... Voice coil motor, 22... Base side yoke, 24... Opposing side yoke,
32...Shaft, 40...Screw hole, 46...Magnet, 50...Support frame.

Claims (1)

[Claims] 1. A voice coil motor for a magnetic disk device that moves a magnetic head along a recording surface of a magnetic disk, the base of the voice coil motor being formed into a flat plate and mounted on the base of the magnetic disk device. a base-side yoke; a shaft having one end fixed to the base-side yoke and the other end protruding from the base-side yoke; a voice coil support frame rotatably attached to the shaft; A voice voice characterized by having an opposing yoke supported by a base side yoke and sandwiching this support frame together with the base side yoke, and a coupling means for firmly coupling the opposing side yoke to the other end side of the shaft. coil motor.