JPH01303622A - Magnetic head device - Google Patents

Abstract

PURPOSE:To maintain the positioning with a high accuracy by fitting an electromagnetic shield plate directly to a supporting arm without contacting it to a head assembly fitting part. CONSTITUTION:An electromagnetic shield plate 1 is directly fitted to the tip of a supporting arm 51 so as not to exert the electromagnetic influence of a data head to a servohead. For this reason, between a magnetic head part 52 positioned at the inner circumferential side of a magnetic disk and a magnetic head part 52 positioned at the outer circumferential side of a magnetic disk, the influence due to the thermal expansion of the electromagnetic shield plate 1 having a linear expansion coefficient different from the raw material of the supporting arm 51 can be suppressed to the minimum. Thus, the relative position error with the servohead and the data head due to the temperature rise or the change of the environmental temperature of a device is made smaller and the positioning accuracy is increased.

Description

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

[Conventional technology]

In general, in a movable head type magnetic disk drive, as soon as there is a request to read specific information on the magnetic disk, the movable head must be rapidly positioned in the radial direction of the magnetic disk to minimize the read time. It won't happen.

A conventional example is shown in FIGS. 2 and 3. In Figure 3,
A head assembly as a magnetic head mounted on the support arm 51 and equipped with a plate spring 52 and a slider 54 is floating at a position facing the magnetic disk 100 as shown in FIG. It is configured to move in the radial direction on the magnetic disk 100 by dynamic motion.

Thereby, the magnetic head section 62 is positioned at a predetermined position on the magnetic disk 100. Here, the position control of the magnetic head 62 is performed by a predetermined servo circuit system.

That is, when positioning the magnetic head 62,
The position of the magnetic head section 62 is detected by a servo head that forms part of the magnetic head section and has a position detection function. Thereafter, the voice coil motor control circuit energizes the voice coil motor coil 60, and the magnetic circuit section 5
The magnetic circuit section 5 is
8 and the coil 60 to generate an electromagnetic force. Then, the support arm 51, which is integrally assembled with the coil 60 and can swing, is swung by the electromagnetic force generated in the coil 60,
As a result, a closed loop (servo circuit system) is formed and functions in which the head assembly mounted on the support arm 51 is moved and the position of the magnetic head section 62 is subsequently detected in the same manner.

Incidentally, in order to improve the recording density of a magnetic disk device and increase the storage capacity of the device, it is necessary to improve the positioning accuracy of the magnetic head section with respect to the magnetic disk. The magnetic head positioning device in current magnetic disk drives has a servo head dedicated to positioning, and this servo head reads positioning information recorded in advance on the magnetic disk surface and performs positioning based on the read information. There is. Therefore, the relative positional error between the servo head and the data head in the magnetic head section that writes and reads other information, and the relative amount of change between the servo disk on which positioning information is written and the other data head are , becomes the deviation amount from the track amount that should be followed, that is, the off-track amount.

The smaller the off-track amount, the higher the positioning accuracy. However, in reality, various factors may cause an amount of off-track that is more than permissible. Among these off-track amounts, off-track caused by a rise in the temperature of the equipment or a change in the environmental temperature is called thermal off-track. The main reason is thought to be the difference in linear expansion coefficients among the various mechanical parts that make up the magnetic disk drive.

Here, the codes 201 and 202 respectively represent the magnetic disk 1.
The lower main board and the upper main board that house the entirety of the magnetic head 62 and the like are shown. Further, each support arm 51 is supported by the housing 80, and the other end thereof can be externally controlled and rotated about the central axis 81.

Moreover, this housing 80 and the above-mentioned magnetic circuit section 58
is fixed on the lower auxiliary board 85 and the upper auxiliary board 86
It is fixed to the lower main board 201 mentioned above in such a way that it is sandwiched between the two.

[Problem to be solved by the invention]

In the conventional magnetic head unit described above, an electromagnetic shielding plate 53° is provided to surround the servo head in order to enable accurate positioning without the servo head dedicated to positioning being affected by the electromagnetic effects of the data head. ing. As shown in FIG. 2, this electromagnetic shielding plate 53 has a mounting portion 51a of the magnetic head portion located on the inner circumferential side of the magnetic disk 100 at the tip of the support arm, and a portion 51a located on the outer circumferential side of the magnetic disk 100. The magnetic head section is mounted directly on the beam 101 connecting the section 51b.

Therefore, if the temperature of the device increases or the environmental temperature changes due to the influence of the electromagnetic shielding plate 53, which is generally made of ferrite or permalloy, which has a different coefficient of linear expansion than the material of the support arm 51, the magnetic disk There has been an inconvenience that a relative positional error between the magnetic head portion, that is, the servo head and the data head located on the inner or outer circumferential side causes thermal off-track.

[Purpose of the invention]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a magnetic head device which improves the disadvantages of the conventional example and in particular reduces the influence of temperature changes on head position control.

[Means to solve the problem]

The present invention includes a support arm formed in a plate shape, a plurality of magnetic head sections attached to the tip of the support arm, and an electromagnetic shielding plate equipped to protect a part of the magnetic head sections. It is equipped with The electromagnetic shielding plate is arranged so as not to come into contact with the magnetic head part and its attachment part, and one end of the electromagnetic shielding plate is fixed to the center side of the support arm. This aims to achieve the above-mentioned purpose.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIG.

Here, the same reference numerals are used for the same constituent members as in the conventional example described above.

The embodiment shown in FIG. 1 includes a support arm 51 formed in a plate shape, a plurality of magnetic head sections 62 attached to the tip of the support arm 51, and a device for protecting a part of the magnetic head sections 62. The electromagnetic shielding plate 1 is equipped with an electromagnetic shielding plate 1. The electromagnetic shielding plate 1 is arranged without coming into contact with the magnetic head part 62 and its attachment part, and one end of the electromagnetic shielding plate 1 is directly fixed to the central part of the support arm. There is.

The magnetic head section 62 includes a servo head and a data head, each of which includes a slider 54 and a leaf spring 52. The electromagnetic shielding plate l is disposed so as to surround the servo head, and as described above, the electromagnetic shielding plate l is arranged so as to surround the servo head.
The support arm 51 is deep in the recess formed at the tip of the
is fixed to the center side.

The servo head reads positioning information recorded in advance on the surface of the magnetic disk, and performs positioning based on the read information. The data head writes and reads information. The electromagnetic shielding plate 1 is directly attached to the tip of the support arm 51 so that the electromagnetic influence of the data head does not affect the servo head. Therefore, the support arm 5
The effect of thermal expansion of the electromagnetic shielding plate, which has a different coefficient of linear expansion from the material of 1, can be minimized, and the relative positional error between the servo head and data head due to increases in device temperature or changes in environmental temperature can be minimized. This has the advantage of increasing positioning accuracy.

Other configurations and effects are the same as those of the conventional example described above.

〔Effect of the invention〕

As described above, according to the present invention, the electromagnetic shielding plate is attached to the head assembly directly on the support arm without contacting the parts, instead of installing a beam connecting the parts and attaching it on the beam. This structure minimizes the effects of thermal expansion of the electromagnetic shield plate, which has a different coefficient of linear expansion than the material of the support arm, and prevents the servo head and data head from collapsing due to a rise in device temperature or changes in environmental temperature. It is possible to provide an unprecedented and excellent magnetic head device that can suppress the relative positional error of , that is, the amount of thermal off-track, to a small value, and thereby maintain high positioning accuracy even when the temperature changes. can.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is a partially omitted perspective view showing an embodiment of the present invention;
FIG. 2 is a perspective view showing a conventional example, and FIG. 3 is an explanatory diagram showing the entire disk device incorporating the conventional example of FIG. 1... Electromagnetic shielding plate, 51... Support arm, 62...
...Magnetic head section. Patent applicant Nippon Electric Co., Ltd. Agent Patent attorney Isamu Takahashi Figure 1 tb Figure 2

Claims (1)

[Claims] (1) A support arm formed in a plate shape, a plurality of magnetic heads attached to the tip of this support arm, and an electromagnetic shielding plate equipped to protect a part of this magnetic head. In the magnetic head device, the electromagnetic shielding plate is disposed without contacting the magnetic head part and its mounting part, and one end of the electromagnetic shielding plate is placed on the side of the central part of the support arm. A magnetic head device characterized by being fixed.