JPH048864B2 - - Google Patents

Description

[Detailed Description of the Invention] [Summary] An actuator structure for a magnetic disk device, in which the actuator is first fixed to a holding block having approximately the same coefficient of thermal expansion as the base within the center plane of the core of a magnetic circuit, and then the holding block is By fixing the block to the frame, temperature stress on the actuator is suppressed, rigidity is maintained, and off-track/vibration is prevented.

[Industrial application field]

The present invention relates to an actuator for a magnetic disk device, and more particularly to an actuator structure that suppresses temperature stress and maintains rigidity when the magnetic circuit of the actuator is attached to a frame made of aluminum or the like.

A magnetic disk device is used as a peripheral device for computers and the like, and records/reproduces data by holding a magnetic head with a small gap between a disk disk rotating at high speed.

In recent years, magnetic disk drives have been required to be more temperature resistant.At the same time, with the trend toward smaller sizes, larger capacities, and higher speeds, the read/write characteristics of heads have become stricter, and the requirements for higher rigidity of actuators have also become stricter. ing. There, no temperature stress occurs.
A disk enclosure (DE) structure with high rigidity is required.

[Conventional technology]

Conventionally, the structure of a rotary actuator has a third
There are those shown in Figs.

In FIG. 3, the side surface of a magnetic circuit 4 is brought into close contact (contact surface A) with the side surface of a housing 3 holding an arm 2 having a magnetic head 1, and a presser plate 5 is fixed with screws 6. Reference numeral 11 represents a disk disk facing the magnetic head 1, and reference numeral 12 represents a swing shaft for rotating the arm.

Figure 4 shows arm 2 (the magnetic head is omitted in the figure).
A structure in which the housing 7 holding the magnetic circuit 8 and the magnetic circuit 8 are completely separated and separately fixed to the base 9, and the contact surface of the magnetic circuit 8 at this time is B. Note that 10 is a screw for fixing the magnetic circuit 8 to the base 9 on the lower side.

Figure 5 shows arm 2 (the magnetic head is omitted in the figure).
The housing 13 holding the magnetic circuit 14 is completely separated and fixed to the base 16 separately, and the coupling between the housing 13 and the magnetic circuit 14 is as follows.
One end is fixed (fixed surface C), and the other end is brought into contact with the D surface via the rollers 15 (there is a gap with the housing 13 on the D surface) to prevent the housing 13 from deforming due to temperature. The magnetic circuit 14 is fixed to the housing 13 by the screws 6 and the holding plate 5, and further fixed to the base 16 by the screws 10.

[Problem that the invention seeks to solve]

In the conventional actuator structure, the combination of the magnetic circuit 4 and the housing 3 shown in FIG. 3 is rigid because they are fixed together. However, since the housing 3 is made of aluminum and the magnetic circuit 4 is made of iron, their coefficients of linear expansion are different. Temperature changes cause temperature stress, deforming the housing 3, and causing the magnetic head 1 on the arm 2 held by the housing 3 to move off-track. There was a drawback that caused this.

The combination of the magnetic circuit 8 and the housing 7 shown in FIG. 4 has the drawback that rigidity is reduced by fixing them separately to the base 9, which lowers the resonance frequency and causes instability of the servo loop.

In the connection between the magnetic circuit 14 and the housing 13 shown in FIG. 5, the magnetic circuit 14 is fixed to the base 16 on the lower side, and further screwed to the housing 13 via the rollers 15 on the side. Temperature stress is the third
Although it is improved over the structure shown in Figures 4 and 4, since the rollers 15 are parallel pins and do not have spring properties, repeated temperature stress may cause the rollers 15 to fall off due to the slight gap created on the D side. There was a problem that it was not possible.

[Means for solving problems]

FIG. 1 is a diagram explaining the principle of the present invention.

FIG. 1 shows a sectional view of the magnetic circuit attached to the frame, with the arm having the magnetic head omitted.

Figure 1 shows the E-type magnetic circuit and frame (base) used in a swing-type actuator for magnetic disks.
17 is an aluminum frame, and the frame 17 is a U-shaped housing to which the movable part is directly attached. At this time, in order to prevent the magnetic circuit 18 from being affected by temperature, an aluminum holding block 22 is placed so that a coupling point 21 is provided on the back surface of the yoke 20 on the central plane of the magnetic circuit center pole 19. After fixing to the block 22 with screws 27, a magnetic circuit is inserted through a magnetic circuit insertion opening 23 provided in advance on the side of the frame, and the outer circumference of the block 22 is fixed to the frame 17 with screws 24. The holding block 22 is made of a material having substantially the same coefficient of thermal expansion as the frame 17 so as not to cause temperature stress. 25 represents a coil, and 26 represents a magnet.

[Effect]

That is, the coupling point 21 between the magnetic circuit 18 and the holding block 22 is provided on the back surface of the yoke on the center surface of the magnetic circuit center ball 19, and the change in the magnetic circuit 18 and the holding block 22 due to temperature is as shown in the figure. There is a degree of freedom for expansion and contraction in the vertical direction, and the holding block 22 is not subjected to temperature stress.
Furthermore, since the joint surfaces of the holding block 22 and the frame 17 are also made of the same aluminum, no temperature stress occurs between them.

The fork bobbin (coil 25) receives a force in the direction of arrow a as a reaction to the force that moves it. Magnetic circuit center ball 19 Yoke 20 on the center plane Back side is screw 2
7, the force in the direction of the arrow a acts as compression, increasing the rigidity and increasing the resonant frequency.

By coupling the magnetic circuit 18 and the frame 17 via the holding block 22, off-track due to temperature of the actuator can be prevented.

〔Example〕

Figures 2A to 2D show diagrams illustrating an embodiment of the present invention, in which A is an internal view of a magnetic disk device, B is a partial view of the magnetic circuit section, C is a view in the direction of arrow P in Figure A, and D is a diagram of the magnetic circuit section. It is a Q arrow view of A. Note that common symbols throughout all figures indicate the same objects.

In Figure 2 A, 17 is the frame (aluminum)
The frame 17 is a U-shaped housing to which the movable parts are directly attached. At this time, in order to prevent the magnetic circuit 18 from being affected by temperature, a holding block (aluminum ) 22 and fixed the magnetic circuit 18 to the holding block 22 with the screws 27, the magnetic circuit 18 is inserted through the magnetic circuit insertion opening 23 provided in advance on the side of the frame 17, as shown in FIG. , the outer periphery of the holding block 22 is fixed to the frame 17 with screws 24. In addition, 1 is a magnetic head, 2 is an arm, 11 is a disk disk,
12 is a swing shaft for rotating the arm, 25 is a coil, 26 is a magnet, and 28 is a spindle for rotating a disk.

The magnetic circuit 18 and the holding block 22 are connected by screws at a connecting point 21 on the back surface of the yoke on the central plane of the magnetic circuit center ball 19. Therefore, changes in the magnetic circuit 18 and the holding block 22 due to temperature have a degree of freedom in expanding and contracting in the vertical direction in the figure, and no temperature stress occurs. Since the fork holding block 22 and the frame 17 are made of the same aluminum, no temperature stress occurs at the joint surfaces.

The reaction force to the force that moves the fork bobbin (coil 25) is a force in the direction of arrow a, which acts as compression at the position where the magnetic circuit 18 and the holding block 22 are fixed with the screw 27, thereby increasing the rigidity. Therefore, the resonant frequency becomes high.

Furthermore, since the holding block 22 is fixed to the same aluminum frame 17, the temperature stress of the magnetic circuit 18 is not applied to the frame 17, so off-track can be prevented.

〔Effect of the invention〕

As explained above, according to the present invention, the core of the magnetic circuit is once fixed to a holding block made of the same material as the frame, and then the holding block is fixed to the frame to prevent temperature stress. This suppresses vibration and maintains rigidity, making it possible to prevent off-track/vibration.

[Brief explanation of drawings]

FIG. 1 is a diagram for explaining the principle of the present invention, FIGS. 2A to 2D are diagrams for explaining an embodiment of the present invention, and FIGS. 3 to 5 are diagrams for inventing a conventional actuator structure. In the figure, 12 is a swing axis, 17 is a frame,
18 is a magnetic circuit, 19 is a center pole, 20 is a yoke, 21 is a connecting point, 22 is a holding block,
23 is a magnetic circuit insertion port, 24 and 27 are screws, 25
26 is a coil, 26 is a magnet, and 28 is a spindle.

Claims (1)

[Claims] 1. In a magnetic disk swing type actuator configured by fixing an E-type magnetic circuit to a frame, a coupling point 21 is provided on the back surface of the yoke 20 on the center plane of the center pole 19 of the E-type magnetic circuit 18. After arranging a holding block 22 having substantially the same coefficient of thermal expansion as the frame 17 and fixing the holding block 22 to the frame 17,
The outer periphery of the holding block 22 is attached to the frame 17.
An actuator structure characterized in that it is configured to be fixed to.