JP2500452B2 - Magnetic disk drive - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic disk device, and more particularly to a magnetic disk device having a plurality of magnetic heads corresponding to a plurality of magnetic disks.

[0002]

2. Description of the Related Art Generally, in a magnetic disk device of this type, a magnetic head is mounted on a rotary type carriage,
On the surface of a magnetic disk that rotates at high speed, air pressure generated between the magnetic head and the magnetic head causes the magnetic head to float at a minute interval, thereby reading and writing magnetic recording. In the carriage of this magnetic disk device, a positioning pattern written on the magnetic disk is read by a servo head and a servo loop is formed for positioning.

Further, research and development of this magnetic disk device have been promoted in the direction of improving the recording density. As a method of improving the recording density, a method of increasing the bit density of the track and a method of increasing the track width are used. There is a method of reducing the track density to increase the track density. Recently, the track width has been reduced to the point of less than 10 [μm].

Conventionally, in a magnetic disk device,
The magnetic disk 51 has a spindle shaft 5 as shown in FIG.
7, the spindle hub 54 and the bearing 55 are attached to the substrate 53 at both ends.
It is rotatably supported via a and 55b. On the other hand, the magnetic head 59 corresponding to the magnetic disk 51 is supported by the arm holder 62 via the arm portion. The arm holder 62 is provided with a cylindrical holder body 62A at the center, and the head rotation support shaft 63 is provided via bearings 64a and 64b.
It is supported by rotation. Then, the reciprocating movement along the magnetic disk is urged to the magnetic head 59 by the torque generated by the head moving drive motor 67 provided at the right end portion of FIG.

The magnetic head 59 comprises at least one servo head 59A used for positioning and a plurality of data heads 50B for reading and writing data. Correspondingly, the arm holder 62 also has at least one servo arm 62a. And a plurality of data arms 62b.

[0006]

By the way, in order to improve the performance of the apparatus as the speed and capacity of computers increase, the flying height of the magnetic head is set smaller and smaller. At present, head flying heights of 0.1 [μm] or less are also announced.

However, when the flying height of the magnetic head 59 is reduced, the electromagnetic conversion characteristics are improved, but the probability that the magnetic head rotating at a high speed collides with the magnetic head increases, and in the worst case, so-called head crash occurs and recording occurs. The inconvenience that the created data is destroyed occurs.

On the other hand, in the conventional magnetic disk drive, the arm holder 62 supported by a plurality of bearings 64A and 64B around the head rotation support shaft 63 fixed to the substrate at both ends is a head moving drive motor. The force generated by 67 causes the rocking motion at high speed. At this time, the assembly of the arm holder 62 and the bearings 64A and 64B is fixed by a method such as close contact, press fitting, or shrink fitting. Therefore, the arm holder 62 is likely to be deformed by the assembly distortion, which causes the arm portion 62 of the arm holder 62 to be deformed.
The relative heights of a and 62b and the magnetic disk 51 may change with time. When such a situation occurs, the flying height of the magnetic head 59 fluctuates to cause a data reading error, and in the worst case, a head crash occurs.

Further, due to the thermal stress generated by the difference in the linear expansion coefficient between the arm holder 62 and the bearings 64A and 64B due to changes in the ambient temperature and the temperature inside the apparatus, the arm holder 6
2 is deformed, the magnetic head 59 is displaced accordingly, so-called thermal off-track occurs, and the written data cannot be read.

[0010]

It is an object of the present invention to improve the disadvantages of the prior art, particularly to effectively eliminate the time-dependent deformation of the arm holder, thereby effectively reducing the displacement of the magnetic head and the occurrence of head crash. It is an object of the present invention to provide a magnetic disk device having good durability.

[0011]

According to the present invention, a plurality of magnetic heads provided corresponding to a plurality of magnetic disks and a central portion for supporting each magnetic head via an arm portion are formed in a cylindrical shape. Arm holder, a head moving drive motor for urging reciprocating movement of the plurality of magnetic heads through the arm holder in the radial direction of the magnetic disk, and a head rotation spindle for supporting the arm holder. In the magnetic disk device including the head rotation support shaft and the plurality of bearings mounted between the arm holder and the arm holder, the outer ring members of the plurality of bearings are integrated by the same member.

Further, a predetermined space is provided between the outer periphery of the outer ring member and the inner peripheral surface of the arm holder.
Further, the outer ring member is fixed to the arm holder via both ends of the outer ring member. This aims to achieve the above-mentioned object.

[0013]

[Operation] Since the outer ring member of the bearing is integrated into the arm holder without directly assembling it by press-fitting or the like, the outer ring member of the bearing and the inner diameter part of the arm holder are generated. Almost no deformation of the holder arm caused by pressurizing assembly strain or difference in linear expansion coefficient can be eliminated, and therefore fluctuation in flying height of the magnetic head can be reduced, and position deviation of the magnetic head and occurrence of head crash can be effectively performed. It can be reduced.

[0014]

An embodiment of the present invention will be described below with reference to FIG. Here, the same reference numerals are used for the same components as those of the conventional example described above.

In the embodiment shown in FIG. 1, a plurality of magnetic heads 59 are provided corresponding to a plurality of magnetic disks 51.
And an arm holder 1 having a cylindrical central portion for supporting the magnetic heads 59 via the arm portions 1a and 1b.
A head moving drive motor 67 for urging reciprocating movement along the radial direction of the magnetic disk 51 over the plurality of magnetic heads 59 via the arm holder 1, and a head rotation support for supporting the arm holder 1. A shaft 63 and bearings 2 and 3 provided at two positions between the head rotation support shaft 63 and the arm holder 1 are provided. The arm holder 1 includes a cylindrical holder body 1A at the center thereof.

The plurality of bearings 2 and 3 have an outer ring member 4 whose outer ring portions are integrated by the same member. Further, a predetermined gap 5 is set between the outer periphery of the outer ring member 4 and the inner peripheral surface of the holder body 1A of the arm holder 1. Further, the outer ring member 4 is fixed to the arm holder 1 via both end portions (upper and lower end portions in FIG. 1) of the outer ring member 4.

The void 5 (= ε) is set as follows.

The diameter of the outer ring member 4 of the bearings 2, 3 is D, the linear expansion coefficient is α1, the linear expansion coefficient of the arm holder 1 is α2, and the temperature change in the substrate including the magnetic head including the environmental temperature change. Is ΔT, the gap ε is expressed as “ε = | α2
-Α1 | × D × ΔT ”or more. In the case of a 3.5-inch magnetic disk device, a value of about 20 [μm] should be calculated, but with a margin, it is usually 100 to 200 [μm].
m] value is adopted.

The plurality of disk-shaped magnetic disks 51 described above
Are centrally supported by a cylindrical spindle hub 54. More specifically, the spindle hub 54 is fixedly mounted around the outer periphery of the spindle hub 54 with a predetermined space therebetween. The spindle hub 54 is configured to rotate at high speed via bearings 55a and 55b by a spindle motor (not shown).

On the other hand, the magnetic head 59 equipped corresponding to the magnetic disk 51 has the arm holder 1 as described above.
Supported by. This arm holder 1 includes bearings 2 and 3
It is rotatably supported by the rotary support shaft 63 via. Bearing 2,
3, the outer ring 3, that is, the outer ring member 4, has a collar-shaped protrusion 4A
The holder main body 1A of the holder arm 1 is fixed to the flange projection 4A by an arm clasp 4B.

In the above embodiment, the arm holder 1 is directly attached to the outer ring portions of the bearings 2 and 3 as in the conventional case.
The outer ring portions of the bearings 2 and 3 are integrally formed with the outer ring member 4 as described above without assembling such as press fitting, and the collar-shaped protrusion 4A is provided, and the holder arm 1 is supported by the collar-shaped protrusion 4A. Then, as described above, the arm clamp 4B is used for fixing. For this reason, there is no deformation of the holder arm 1 due to the assembly strain generated in the outer diameter portion of the outer ring member 4 of the bearings 2 and 3 and the inner diameter portion of the arm holder 1 or the difference in the linear expansion coefficient, and therefore the magnetic head. It is possible to reduce fluctuations in the flying height of the magnetic head, and to effectively reduce the positional deviation of the magnetic head and the occurrence of head crash.

Next, another embodiment will be described with reference to FIG. In the embodiment shown in FIG. 2, the outer ring member 4 of the bearings 2 and 3 is used.
And the outer ring member 4
However, it is formed of a material having a linear expansion coefficient substantially the same as the linear expansion coefficient of the arm holder 1. And in this case,
The outer ring member 4 is closely fitted inside the holder body 1A of the arm holder 1. Also, of the bearings 2 and 3, the other bearing 3
Has a structure in which the rotary support shaft 63 is used as an inner ring member thereof. The other structure is the same as that of the embodiment shown in FIG.

Therefore, in this case as well, similar to the case of the embodiment shown in FIG. 1 described above, even if the environmental temperature and the device temperature change, the space between the outer ring member 4 of the bearings 2 and 3 and the arm holder 1 is changed. Causes almost no thermal stress, and the deformation of the arm holder 1 is almost eliminated. Therefore, the fluctuation of the flying height of the magnetic head can be reduced, and the displacement of the magnetic head and the occurrence of head crash can be effectively reduced. it can.

[0024]

Since the present invention is constructed and functions as described above, it is possible to effectively suppress the deformation of the arm holder due to internal strain, temperature change, and the like that occur during assembly, and thus the magnetic head It is possible to provide a highly reliable magnetic disk device in which the positional deviation is small, the occurrence of head crash is effectively suppressed, and the durability is increased at the same time.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is a partial sectional view showing another embodiment.

FIG. 3 is a cross-sectional view showing a conventional example.

[Explanation of symbols]

 1 Arm Holder 1A Holder Main Body 1a, 1b Arm Part 2, 3 Bearing 4 Outer Ring Part 5 Magnetic Head 51 Magnetic Disk 59 Magnetic Head 63 Head Rotating Spindle 67 Head Moving Drive Motor Part

Claims (2)

(57) [Claims] 1. A plurality of magnetic heads provided for a plurality of magnetic disks, an arm holder having a cylindrical central portion for supporting each magnetic head via an arm portion, and the arm holder. A head moving drive motor for urging reciprocating movement of the entire plurality of magnetic heads along the radial direction of the magnetic disk, a head rotation spindle supporting the arm holder, and the head rotation spindle. In a magnetic disk device including a plurality of bearings mounted between the arm holder and the arm holder, outer ring members of the plurality of bearings are integrated by the same member, and an outer periphery of the outer ring member and an inner peripheral surface of the arm holder. A magnetic disk device characterized in that a predetermined gap is provided between the outer ring member and the arm holder, and the outer ring member is fixed to the arm holder via both end portions of the outer ring member. 2. A plurality of magnetic heads equipped to correspond to a plurality of magnetic disks, an arm holder having a cylindrical central portion for supporting each magnetic head via an arm portion, and the arm holder. A head moving drive motor for urging reciprocating movement of the entire plurality of magnetic heads along the radial direction of the magnetic disk, a head rotation spindle supporting the arm holder, and the head rotation spindle. In a magnetic disk device including a plurality of bearings mounted between the arm holder and outer ring members of the plurality of bearings, the outer ring members are integrated by the same member, and the outer ring member has a linear expansion coefficient of the arm holder. A magnetic disk device characterized by being formed of a material having a coefficient of linear expansion substantially the same as