JPH0376060A - Head positioning device for magnetic disk device - Google Patents

Abstract

PURPOSE:To prevent the attitude variation of a magnetic head and a head crash caused by dust by giving a pre-load of a bearing part by the magnetic force of a pair of permanent magnets. CONSTITUTION:A shaft 1 is supported by the upper base 6 and the lower base 12, and an arm holder 2 is supported through a bearing 5 by the shaft 1. Also, a permanent magnet 3 is movable in the axial direction of the shaft 1 and brought into contact with the rotary bearing 5 of the upper base 6 side, and the permanent magnet 4 is fixed to the upper base 6 so as to hold the suitable interval of a prescribed value to the permanent magnet 3, and gives a pre-load in the axial direction to the bearing 5 by the repulsion of the permanent magnets 3, 4. In such a manner, the variation of attitude of a magnetic head and a head crash caused by dust at the time of assembly and at the time of operation can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a head positioning device for a magnetic disk device.

[Conventional technology]

In a head positioning device for a magnetic disk device, an arm assembly including an arm that holds a magnetic head and an arm holder that supports this arm is fixed via a bearing and fixed to a shaft (shaft) by an electromagnetic force generated by a coil and a permanent magnet. ) rotates at high speed around the magnetic disk, and reads and writes information to and from the magnetic disk using a magnetic head. A normal bearing is a ball bearing consisting of an inner ring, an outer ring, and a ball retainer, but because it has a gap (backlash) called a radial clearance, it is extremely difficult to use, such as in the head positioning device (carriage) of a magnetic disk drive. When precision is required, a preload is applied to the inner or outer ring to eliminate the above-mentioned play.

In the conventional head positioning device, as illustrated in FIG. 3, a load is applied by a coiled thrust spring 36 that presses the shaft 21 in the axial direction. However, the conventional preloading method as described above has problems such as contact areas that occur when the thrust spring 36 contacts a preloaded part such as the inner support 35 during assembly, and slippage during high-speed rotational movement.

There are minute dusts generated due to the vibrations caused by the natural frequency of the strike spring 36, which has the disadvantage that they may get between the magnetic head and the magnetic disk (medium) and cause a head crash. There is.

[Problem to be solved by the invention]

As mentioned above, the preload system of the conventional swing arm type head positioning device for magnetic disk drives has a complicated structure from the viewpoint of miniaturization and weight reduction of magnetic disk drives. This is the upper limit. As described above, the head positioning device of conventional e-magnetic disk drives has the problem that the posture of the magnetic head changes due to dust during assembly and operation, causing a head crash in the worst case, and its structure is complicated. Therefore, there is a problem that there is a limit to the progress of miniaturization.

[Means to solve the problem]

A head positioning device for a magnetic disk device according to the present invention is a head positioning device for a magnetic disk device that has an arm assembly that holds a magnetic head that rotates about a fixed shaft. A first magnet magnetized in the direction of the axis is fixed to the inner ring or outer ring of, and a second magnet magnetized in the direction of the axis opposite to the first magnet is fitted into the inner ring or outer ring on the preload side. It is fixed to the shaft or the arm assembly as shown in FIG.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

The embodiment of the head positioning device for the magnetic disk drive shown in FIGS. 1 and 2 has an upper base 6 and a lower base 12.
The shaft 1 is supported by the arm holder 2.
is supported by the shaft 1 via a bearing 5. A swing arm 14 for holding a magnetic head 13 is attached to the tip of the arm holder 2, and a winding 9 is attached to the arm holder 2.
A coil bobbin 10 wound with is fixed. A magnetic circuit including a housing 11, a yoke 7, and a permanent magnet 8 is fixed by an upper base 6 and a lower base 12 so as to maintain an appropriate distance from the coil bobbin 10. The permanent magnet 3 is movable in the axial direction of the shaft 1, and is in contact with a rotary bearing 5 on the upper base 6 side in the figure. A permanent magnet 4 is fixed to the upper base 6 so as to maintain an appropriate distance of a predetermined value from the permanent magnet 3. The repulsive forces of these permanent magnets 3 and 4 apply an axial preload to the bearing 5.

〔Effect of the invention〕

As explained above, in the head positioning device for a magnetic disk drive of the present invention, by applying preload to the bearing section using the magnetic force of a pair of permanent magnets, there is no contact section at the J load application point, and dust generation during assembly is drastically reduced. It has the effect of Therefore, it is possible to prevent a change in the posture of the magnetic head and a head crash due to the generated dust. Furthermore, since the configuration is simple, it is also effective in promoting miniaturization.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing one embodiment of the present invention, and FIG.
FIG. 3 is an enlarged cross-sectional view showing details of the main part of the embodiment shown in the figure, and FIG. 3 is a cross-sectional view showing an example of a conventional head positioning device for a magnetic disk device. 1.21...Shaft, 2.22...Arm holder, 3.4.8.28...Permanent magnet, 5.25...Bearing, 6.26...Upper base, 7.27 ... Yoke, 9.29 ... Winding wire, 10.30 ... Coil bobbin, 11.31 ... Housing, 12.32 ... Lower base, 13.33 ... Magnetic head, 14.34
...Arm, 35...Inner supporter, 36...
thrust spring.

Claims (1)

[Claims] In a head positioning device for a magnetic disk drive having an arm assembly that holds a magnetic head that rotates around a fixed shaft, the inner ring or outer ring on the preload side of the bearing of the shaft is magnetized in the direction of the shaft. A first magnet is fixed, and a second magnet facing the first magnet and magnetized in the direction of the shaft is fixed to the shaft or the arm assembly so as to fit into the inner ring or outer ring on the preload side. A head positioning device for a magnetic disk device, characterized in that: