JPS6199977A - Magnetic disk device - Google Patents

Abstract

PURPOSE:To constitute a titled device so that thermal distortion of a bearing and an arm supporting body is not concentrated on a specified head by providing a rotary type positioning mechanism in which a cylindrical sleeve by which a distance of the axial direction of a rotation coincides with the arm supporting and fixing an arm group on which a magnetic head group has been loaded, and plural bearings. CONSTITUTION:When a sleeve 6 whose material quality is different from that of an arm supporting body 3 is interposed between the arm supporting body 3 and a bearing 2, and that of a coefficient of linear expansion equal to that of a bearing steel is used as the material quality of the sleeve 6, a thermal stress is generated in a fitting part of the bearing 2 and the sleeve, and also since a contact part of the sleeve 6 and the arm supporting body 3 is equidistant in the axial direction, a uniform thermal stress is generated in the arm supporting body 3. This face gives the same motion to all arms 5 held fast by the arm supporting body 3, and as a result, relative displacement of a data head and a servo-head is not generated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic disk device, and more particularly to a magnetic disk device having a rotary type magnetic head positioning mechanism.

[Conventional technology]

The positioning mechanism of magnetic disk devices can be roughly divided into two types: a page line type and a rotation type.The latter is often used in general KFi mid-capacity positioning. Some high-density recording requires 1k of iJl amplifiers in the device, so increasing Ktf positioning accuracy is a major concern.

Currently, the most common magnetic head positioning method found in magnetic disk devices is that a servo head dedicated to positioning is provided, and the servo head reads positioning information pre-recorded on the magnetic disk surface facing the servo head, and the positioning mechanism It depends on how it works. Therefore, the relative positional difference between the servo head and other data heads (%/1) is the relative displacement between the servo disk on which positioning information is written and the other data disks, and the deviation from the track that is originally supposed to be followed. This is the off-track amount. The smaller the off-track amount is, the higher the positioning accuracy will be. However, in reality, more off-track urine than permissible may occur due to various factors. Offtrack Co., Ltd. also deals with temperature rises in equipment.Offtracks caused by changes in environmental temperature are called thermal offtracks, and are caused by differences in linear expansion coefficients between the various mechanical parts that make up magnetic disk drives. considered to be the main factor.

The main parts of the conventional general structure of the above-mentioned rotary positioning mechanism are shown in Figure 2 (a) and (bl). In the figure, the coil and magnetic circuit that generate the driving force of the positioning mechanism are shown. It is drawn with parts such as omitted.

A fixed shaft 1 rotates an arm support 3 via a bearing 2. The arm support 3 supports and fixes an arm 5 on which a magnetic head 4 is mounted. The method of supporting and fixing it is arm 5.
Generally, the end face of the arm support member 3 is pressed against the arm support member 3, and the arm support member 3 is firmly held with a special bolt.

[Problems to be solved]

In the case of such a positioning mechanism in the above-mentioned conventional magnetic disk drive, the IC is made of aluminum or the like for the arm support 3 or the arm 5 in order to reduce the weight. Since the bearing is made of 2Fi bearing steel, thermal stress may occur at the fitting portion between the two due to the difference in linear expansion coefficient between the two.

This leads to deformation of the arm support 3, ie the behavior of the arm 5 close to the bearing 2 becomes different compared to the behavior of the arm 5 remote from the bearing 2. To state the phenomenon more simply, if there is a change in ambient temperature, the movement of arm 5 will be about 1 degree lower than that of bearing 2.
There is a problem that the magnetic heads 4 are not uniform due to the difference in the relationship, resulting in relative displacement between the magnetic heads 4, and an improvement in this point has been desired.

[Means for solving problems]

The present invention aims to solve the above-mentioned conventional problems, and as a means for solving the problem, a magnetic disk in which a group of magnetic heads positioned facing a plurality of magnetic disks is operated by a rotary positioning mechanism. In the device, between an arm support that supports and fixes the arm group on which the magnetic head group is mounted and a plurality of bearings, the material is different from that of the arm support, and the distance in the axial direction of rotation is the same as that of the arm support. It is an object of the present invention to provide a magnetic disk device characterized by having a rotary positioning mechanism in which a cylindrical sleeve is interposed.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings. Figure 1 (a), (bl is Figure 2 (al, (b)
), it shows the main parts of the rotary positioning mechanism according to the present invention. Basically, it is substantially the same as the conventional example, but the difference from the conventional example is that a sleeve 6 made of a different material from that of the arm support 3 is interposed between the arm support 3 and the bearing 2. That is, the unusual deformation of the arm support 3 near the bearing 2 caused by temperature changes observed in the conventional example, that is, the thermal strain caused by the fitting of the outer ring portion of the bearing 2, can be avoided by the sleeve, which is a feature of the structure of the present invention. 6 causes the arm support 3 to deform uniformly in the axial direction. More specifically, for example, if the sleeve 6 is made of a material with a coefficient of linear expansion equivalent to that of bearing steel, thermal stress will not occur at the fitting portion between the bearing 2 and the sleeve 6, and the sleeve 6 and arm support Since the contact portions with the arm support 3 are equidistant in the axial direction, a uniform thermal stress is generated on the arm support 3. This gives the same movement to all of the arms 5 that are firmly supported on the arm support 3, resulting in no relative displacement between the data head and the servo head.

〔Effect of the invention〕

As described above, the present invention provides a magnetic disk drive in which a group of magnetic heads located facing a plurality of magnetic disks operates by a rotating dust positioning mechanism, in which a group of arms on which the group of magnetic heads is mounted is provided. A cylindrical sleeve is interposed between the arm support to be supported and fixed and the plurality of bearings, and is made of a different material from the arm support and whose distance in the axial direction of rotation matches that of the arm support. Since the configuration has a rotary positioning mechanism, it is possible to prevent the thermal strain between the bearing and the arm support from concentrating on a specific head, which has the effect of reducing the amount of thermal off-track, which in turn improves the magnetic disk drive. This has the effect of contributing to higher performance.

[Brief explanation of the drawing]

FIGS. 1(a) and 1(b) are a side view and a plan view showing the main parts of a rotational positioning mechanism of a magnetic disk device according to an embodiment of the present invention, and FIG. 1 is a side view and a plan view showing main parts of a rotational positioning mechanism of a magnetic disk device as a conventional example.

Claims (1)

[Claims] In a magnetic disk drive in which a group of magnetic heads positioned facing a plurality of magnetic disks operates by a rotary positioning mechanism, an arm support and a plurality of bearings support and fix an arm group on which the group of magnetic heads is mounted. and a rotary positioning mechanism in which a cylindrical sleeve is interposed between the arm support and a cylindrical sleeve made of a material different from that of the arm support and whose rotational distance in the axial direction matches that of the arm support. Features of magnetic disk device.