JPH02287982A - Magnetic disk device - Google Patents

Abstract

PURPOSE:To suppress the occurrence of a warp in a connecting part between a yoke and a base plate by using one washer having the same linear expansion coefft. as the yoke for plural screws when the yoke in a magnetic circuit is fixed to the base plate with screws. CONSTITUTION:The washer 12 capable of fitting commonly to plural fixing screws 11 is embedded into the back side of the base plate 10, and the fixing screws 11 are screwed from the lower side via this washer 12 into a carriage housing 9 which is integrated with the yoke 7. The housing 9 is made of the same magnetic material a the yoke, while the washer 12 is made of a material having the same linear expansion coefft. as the housing 9. Consequently, an interval between plural fixed screws in the washer 12 is expanded and shrunk in accordance with a temp. change to keep the same interval as the screwed part of the housing 9. By this method, a warpage of the connecting part between the housing 9 and the base plate 10 is suppressed.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a magnetic disk device.

[Conventional technology]

FIG. 2 shows the general configuration of a magnetic disk device to which the present invention is applied, in which (a) is a view seen from the front on the flat side of the magnetic disk; ) is a view seen from the side next to the arrow. In FIG. 2, the arm 3 is rotatable by a rotating shaft 5, and a magnetic head 2 is attached to the tip of the arm 3, and the magnetic head rotates at high speed. Any track can be accessed by rotating the arm 3 with respect to the disk 1.A plurality of arms 3 are stacked along the rotation axis 5, and a magnetic head 2 is attached to the tip of each arm 3. The entire structure moves as one.

Further, a coil 4 is integrally formed at the rear end of the arm 3, and this coil 4 includes a yoke 7, a magnet 8A,
The arm 3 is placed in the magnetic path of the magnetic circuit formed by the magnets 8A and 8B, and is rotated to a desired position by the attraction or attractive force between the magnetic flux generated by energizing the coil 4 and the magnetic flux of the magnets 8A and 8B. It is possible to move.

The yoke 7 is formed integrally with the carriage housing 9, as shown in FIG.
The other end is held by the upper support plate 6.

On the other hand, FIG. 3 shows a view viewed from the direction of arrow B in FIG. It has become.

[Problem to be solved by the invention]

Conventional magnetic disk drives are configured as described above, and there were no problems with basic functions such as writing and reading data, but mechanical deformation due to changes in environmental temperature caused the magnetic head 2 to There was a drawback that positioning was difficult.

That is, as described above, since the carriage housing 9 is formed integrally with the yoke 7, a magnetic iron-based material is used. Further, the base plate 10 is made of aluminum alloy or the like for ease of molding and weight reduction of the device. Therefore, when a large difference in environmental temperature occurs, a difference in expansion occurs between both members of the carriage housing 9° base plate 10 fixed with a plurality of fixing screws 11 depending on the difference in coefficient of linear expansion, and both or one of the members Warping occurs, which affects the positioning of the arm 3 and, ultimately, the magnetic head 2. If such a condition occurs when writing and reading data, there is a risk that data cannot be read or written normally due to off-track. There is.

Although it is possible to correct a certain degree of positional deviation using a servo mechanism, there is a limit to tracking when the recording density becomes higher.

The present invention has been devised in view of the above points, and its purpose is to reduce the occurrence of warpage at the joint between the carriage housing (yoke) and the base plate in response to changes in environmental temperature, and to An object of the present invention is to provide a magnetic disk device that can stably read and write data by making the track smaller.

[Means to solve the problem]

In order to achieve the above object, the present invention has a structure in which a yoke of a magnetic circuit that drives an arm having a magnetic head attached to its tip is directly fixed to a base plate by a plurality of screws, and the yoke and the base plate are made of different materials. In the magnetic disk drive, a washer made of a material having the same coefficient of linear expansion as the yoke is fitted on the non-yoke side of the screws in common to the plurality of screws.

(Function) In the magnetic disk drive of the present invention, a material having the same coefficient of linear expansion as the yoke is fitted on the non-yoke side of the screws fixing the yoke and the base plate in common to a plurality of screws. The washer expands at the same rate as the yoke as the environmental temperature changes.

It contracts, equalizing the displacement at both ends of the screws, and suppressing the occurrence of warpage at the joint between the yoke and the base plate.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a configuration diagram showing an embodiment of a magnetic disk device of the present invention. Note that the other configuration is an interpolation of FIG. 2 explained in the section of the conventional example, and FIG. 1 is a view seen from the direction of arrow B in FIG. 2(a), and FIG. 3 of the conventional example corresponds to

The difference in FIG. 1 from the conventional example (FIG. 3) is that a washer 12 made of a material having the same linear expansion coefficient as the yoke 7 is provided on the head side (non-yoke side) of the fixing screw 11. That is, a washer 12 to which a plurality of fixing screws 11 can be commonly fitted is embedded in the back side of the base plate 10, and the fixing screw 11 is screwed into the carriage housing 9 integrated with the yoke 7 from below through the washer 12. There is.

Note that the shape of the washer 12 is not particularly limited as long as it can fit with the plurality of fixing screws 11 without any gaps.

Therefore, when a large difference in environmental temperature occurs, the intervals between the portions of the plurality of fixing screws 11 screwed into the carriage housing 9 expand and contract in accordance with the linear expansion coefficient of the iron-based material that is the material of the carriage housing 9. . On the other hand, the base plate 10 expands and contracts depending on the linear expansion coefficient of its material, such as aluminum alloy, and tends to warp at the joint with the carriage housing 9. However, since the washer 12 into which the head side of the fixing screw 11 is screwed is formed of a material with the same coefficient of linear expansion as the carriage housing 9, the intervals between the plurality of fixing screws 11 on the washer 12 side are It expands to the same spacing as the inserted part.

Shrink. As a result, the warpage that would occur at the joint between the carriage housing 9 and the base plate 10 is suppressed.

Therefore, even if there is a large difference in the environmental temperature between when data is written to the magnetic disk 1 and when data is read, the positional deviation of the magnetic head 2 is as small as the linear expansion of each component. Since the positional deviation is not large due to warping of the carriage housing 9 or the base plate 10, off-track does not occur to the extent that it affects reading, and therefore stable data reading and writing can be performed.

It goes without saying that the present invention can be applied not only to the case of fixing with the fixing screw 11 but also to other fixing means such as rivets.

〔Effect of the invention〕

As explained above, in the magnetic disk drive of the present invention, a washer is fitted in common to a plurality of screws on the non-yoke side of the screws that fix the yoke and the base plate, and this washer is fitted in the same way as the yoke. Since the washer is made of a material with a coefficient of linear expansion, the washer expands and contracts at the same rate as the yoke as the environmental temperature changes, and the displacement at both ends of the screws is the same to prevent warping at the joint between the yoke and the base plate. This has the effect of suppressing occurrences, reducing off-trunk space, and stabilizing data reading and writing.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing an embodiment of a magnetic disk device of the present invention, FIG. 2 is a configuration diagram of a magnetic disk device to which the present invention is applied, and FIG. 3 is a configuration diagram of a conventional magnetic disk device. In figure A, l...Magnetic disk 2...Magnetic head 3...Arm 4...Coil 5...Rotary shaft 6... ... Upper support plate 7 ... Yoke 8A, 8B ... Magnet 9 ... Carriage housing 10 ... Base plate 11 ... Fixing screw 12 ... One-shaft man 1 Patent applicant: Ibaraki NEC Co., Ltd.

Claims (1)

[Scope of Claims] A magnetic disk drive in which a yoke of a magnetic circuit that drives an arm having a magnetic head attached to its tip is directly fixed to a base plate by a plurality of screws, and the yoke and the base plate are made of different materials. . A magnetic disk device, wherein a washer made of a material having the same coefficient of linear expansion as the yoke is fitted on a non-yoke side of the screws in common to the plurality of screws.