JPH02230566A - Positioning mechanism for magnetic disk device - Google Patents

Abstract

PURPOSE:To improve the positioning accuracy of a head by always bringing a viscoelastic member mounted by using the inner wall of an actuator into contact with the outer diameter of a compression coil spring which applies a thrust pre-load force on a ball bearing. CONSTITUTION:The viscoelastic member 19 is mounted on the inner wall of the actuator 7, and the viscoelastic member 19 always comes in contact with the outer diameter of a pre-load compression spring 18 in a thrust direction, and when oscillation occurs in the compression direction of the spring 18, oscillation energy is absorbed by the viscoelastic member 19. Therefore, the occurrence of the oscillation affecting on the thrust direction of the actuator and the positioning direction of the head can be suppressed. In such a way, the positioning of the head can be performed with high accuracy.

Description

[Detailed Description of the Invention] [Object of the Invention] (Field of Application in Industry) This invention relates to a magnetic disk device, and in particular, it relates to a magnetic disk device in which a head is moved along the circumference of a disk medium on which information is recorded. The present invention relates to a positioning mechanism for a magnetic disk drive having an actuator that can be reciprocated and positioned.

(Prior Art) Recently, there has been an increasing demand for a compact, large-capacity magnetic disk drive in the Winchester type magnetic disk drive. As a result of recent developments, it has become possible to increase track density, and attempts have therefore been made to provide actuators that are compact and can be accessed at extremely high speeds.

Conventional techniques used for this purpose are shown in FIGS. 3 and 4. A head suspension system 25 equipped with a magnetic head 24 capable of recording and reproducing is attached to an arm assembly 2.
It is attached by 9. This arm assembly 2
9 is mounted on and supported by the actuator body 27, which is supported by two ball bearings 36a, 36b attached to both ends of a fixed shaft 28, which is fixed to plates 34a, 34b connected to the magnetic circuit 35. has been done.

This actuator 27 is rotated and oscillated by a voice coil motor 30.

A position signal written on the magnetic disk 21 is read by the magnetic head 24, this position signal is fed back to the voice coil motor 30, and the magnetic head 24 is positioned by the operation of a positioning servo system.

Here, the fixed shaft 28 and the rotatable actuator body 27
The support (fixation) and structure of this is shown in Figure 4. The fixed shaft 28 is supported by two lower connecting plates 34a and 34b which are supported by a magnetic circuit. This fixed shaft 2
8. On the outer diameter part, there are ball bearings 36a, 3 in the downward direction.
The inner ring of 6b is attached. The outer ring of one of the lower bearings 36a in the figure is fixed to the inner periphery of the actuator main body 27. The other ball bearing 36b has an outer ring holder 37 that is always in contact with the outer ring of the ball bearing, and an actuator main body 27.
A compression spring 38 is installed between the ball bearing 36b and a portion provided on the inner peripheral side, so that a thrust preload is applied to the outer ring of the ball bearing 36b. Also, this hall bearing 36
b In order to apply a preload force in the radial direction to the outer ring, a compression spring 40 is provided in the same direction as the magnetic gap direction of the head.

(Problem to be solved by the invention) However, the conventional ball bearing outer ring has a thrust
- In the method of providing a compression spring to apply preload, if this compression spring causes its own vibration, the magnetic disk drive is High speed and high viscosity positioning have made it difficult.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a positioning mechanism for a magnetic disk device that can increase speed and improve head positioning accuracy.

[Structure of the Invention] (Means for Solving the Problems) In order to solve such problems, the present invention provides a magnetic head for reading and writing information to and from an information recording medium, and a magnetic head that supports the magnetic head. and a rotary-oscillating actuator supported by ball bearings at one end and the lower end of a fixed shaft in order to support the arm and move the magnetic head to a position for reading and writing information. In a magnetic disk drive, one ball bearing is fixed to the inner peripheral surface of the actuator, and the other ball bearing is preloaded in the thrust direction by a compression spring, and the gap between the compression spring and the inner wall of the actuator is filled with viscoelastic material. The viscoelastic member is filled with a member so that the viscoelastic member contacts the compression spring.

(Function) The function of the present invention will be explained. By attaching a viscoelastic member to the inner wall of the actuator and constantly contacting the outer diameter of the preload compression spring in the thrust direction, when vibration occurs in the compression direction of the spring, the vibration energy of the spring is absorbed. The elastic profit is absorbed. Therefore, the occurrence of vibrations that affect the thrust direction of the actuator and the head positioning direction can be suppressed. As a result, highly accurate head positioning becomes possible.

(Example) Hereinafter, this invention will be explained based on the drawings.

1 and 2 are diagrams showing an embodiment of a magnetic disk device according to the present invention. In this embodiment, a swing type magnetic disk device for an inline type head assembly system is shown.

First, the configuration will be explained.

In the figure, reference numeral 1 denotes a substantially disk-shaped magnetic disk for recording or reproducing information, and a large number of magnetic disks 1 are stacked and arranged in a spindle motor 3 in a case 2. As shown in FIG. Magnetic heads 4a and 4b that access the magnetic disk 1 to read and write information are arranged on both sides of the magnetic disk 1. The magnetic heads 4a and 4b are attached to a board-shaped suspension 5a5b in order to float and face the surface of the magnetic disk 1 (slightly floating above the surface of the magnetic disk 1). The suspensions 5a, 5b are attached to an arm 6, and the arm 6 is attached to an actuator body 7.

A voice coil motor 10, which is a type of linear motor, is provided on the base end side of the actuator body 7. The voice coil motor 10 has a structure in which a coil frame 12 around which a drive coil 11 is wound is attached to the base end side of an actuator body 7, and permanent magnets 14a and 14b are installed at both upper and lower ends of the drive coil 11. It has become.

Further, in the vertical direction of the voice coil motor 10, there are connecting plates 14a and 14b for supporting the fixed shaft 8 which becomes the pivot of the actuator. In the actuator body 7, ball bearings 14a and 14b located above and below the fixed shaft 8 are fixed to the fixed shaft 8 as inner rings.
Further, outer rings of these ball bearings 16a, 16b are fixed to the inner diameter portion of the actuator body 7. In this fixing method, the outer ring of one of the ball bearings 16a is fitted into the inner diameter portion of the actuator body 7 or is fixed by bonding. Also, the other ball bearing 16b
Between the outer ring holder 17, which is always in contact with the outer ring part, and a part provided on the inner circumferential side of the actuator main body 7,
A compression coil spring 18 is placed, and a ball bearing 16 is placed at all times.
A preload force in the thrust direction is applied to the outer ring portion of b. Also, on the side surface of this ball bearing outer ring, there is a compression coil spring 20 for applying preload force in the radial direction.
is provided in the same direction as the head magnetic gap.

By the way, a viscoelastic member 19 installed on the inner peripheral wall of the actuator main body 7 is always in contact with the outer diameter portion of the compression coil spring 18 for preloading in the thrust direction. Now, this viscoelastic member 19 utilizes the inner wall of the actuator main body 7, and their surfaces are fixed with adhesive or the like. By subsequently inserting the compression coil spring 18, assembly can be easily performed.

With the configuration method described above, the actuator main body 7 can be rotated and oscillated, and the magnetic head 4 can be moved to a certain position.

The position signal written on the magnetic disk 1 is transferred to the magnetic head 4.
This position signal is fed back to the voice coil motor 10, and the positioning servo system is operated to position the magnetic head 4.

Next, the action will be explained.

The compression coil spring 18 for applying a preload force in the thrust direction to the outer ring portion 16b of the ball bearing has a shape in which a part of the outer diameter portion of the spring 18 is covered by a viscoelastic member 19 that is in constant contact with the outer diameter portion. become. and compression coil spring 1
8 causes vibration in the thrust direction, the viscoelastic member 19
absorbs the vibration energy of the spring 18 and no longer transmits the vibration to the outer ring of the ball bearing 16b. This results in a compression coil spring 18 with any mechanical resonance frequency.
Even when the head is used, vibrations in the thrust direction can be suppressed, so head positioning can be performed with high precision.

In this invention, a method has been shown in which the viscoelastic member attached to the inner wall of the actuator pushes the outer diameter of the preload spring in the thrust direction. There is also a method of inserting it, and the same effect can be obtained in this case as well.

[Effects of the Invention] As described above, according to the present invention, the viscoelastic member attached using the inner wall of the actuator is constantly in contact with the outer diameter of the compression coil spring that applies thrust preload to the ball bearing. By doing so, even if the compression coil spring vibrates in the thrust direction, it is possible to suppress the vibration component in the head positioning direction, and it is possible to obtain a positioning mechanism for a magnetic disk device that is a highly accurate head positioning mechanism. It became.

[Brief explanation of the drawing]

1 and 2 are a perspective view and a sectional view showing an embodiment of the positioning mechanism of a magnetic disk device of the present invention, and FIGS. 3 and 4 are perspective views showing a conventional magnetic disk device positioning mechanism. FIG. 2 is a diagram and a sectional view. 1, 21... Magnetic disk single plate, 2, 22... Housing, 3, 23... Spindle motor, 4.24... Magnetic head F, 5.25... Magnetic head suspension ,
626... Head support arm, 7.27... Actuator body, 8, 28... Fixed shaft, 10.30...
・Voice coil mode, 11.13...Coil, 12
, 32... Coil frame, 13. 33... Magnet, 14.
34...Connection plate, 15.35...Magnetic circuit, 16.
36...Ball bearing, 17.37...Outer ring holder, 18.38...Compression spring for thrust direction preload,
19... Viscoelastic member, 20.40... Compression coil spring for radial direction preload.

Claims (1)

[Claims] An information recording medium for recording or reproducing information, a magnetic head for reading and writing information on this information recording medium,
An arm that supports this magnetic head, and a rotating swing type that is supported by ball bearings at the upper and lower ends of a fixed shaft to support this arm and move the magnetic head to a position where information is read and written. In a magnetic disk drive equipped with an actuator, one ball bearing is fixed to the inner peripheral surface of the actuator, and the other ball bearing is preloaded in the thrust direction by a compression spring. A positioning mechanism for a magnetic disk device characterized by filling a gap with a viscoelastic member.