JPH02220274A - Data storage device - Google Patents

Abstract

PURPOSE:To detect a track position with simple and small constitution by detecting multipolar magnetization of a rotary body provided to a rotary shaft of a rotary type actuator with magnetic resistor (MR) element. CONSTITUTION:A track of a magnetic disk 3 is detected by a magnetic head 1 provided on the rotary type actuator 4. The rotary shaft of this actuator 4 is provided with a multipolar-magnetized disk 8, and this magnetization information is read out by the MR element 9, and the track position on the disk 3 is detected out in simple and small constitution, and then the inertia of the actuator is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a data storage device with a rotary actuator equipped with a magnetic encoder.

[Prior art and its problems]

Recently, the density of data storage devices has been increasing, and as a means for achieving this, devices equipped with track positioning servos are being used more frequently.

In these devices, as a means for obtaining track position information, for example, in the case of a magnetic recording disk device, 1) a so-called servo surface servo method having a dedicated servo surface on which track position information is continuously recorded on the disk surface; ) Data surface servo method (sector servo method) in which position information is intermittently recorded on the data surface 3) Optical encoder servo method in which the actuator is equipped with an optical encoder (for example, see US Pat. However, they all have the following problems.

That is, method 1) allows continuous position information to be obtained, but requires a dedicated servo surface, which has the drawback of reducing the total storage capacity.

Although the method 2) compensates for this drawback, since the position information is intermittent, it takes time to recognize the position information, which increases the head access time, and has the disadvantage that it takes time to input and output data.

Furthermore, 3) is intended to compensate for the drawbacks of both, but the configuration of the optical encoder is complicated and requires a distance in the optical axis direction.

Alternatively, there is a drawback that the inertia of the actuator is increased due to its configuration.

It is also necessary to pay attention to environmental resistance.

[Problems to be Solved by the Invention] The present invention has a space-saving and simple configuration, and provides data storage that allows continuous acquisition of actuator and track position information without reducing storage capacity. The aim is to provide equipment.

[Means to solve the problem]

The present invention was made to solve the above problems,
A rotating body with multi-pole magnetization is installed in the circumferential direction around the rotation axis of the actuator, and a so-called MR element whose electrical resistance changes depending on the strength of the magnetic field is installed opposite to this to detect the position of the actuator. It is equipped with a magnetic encoder.

The structure of the rotating body, which is multi-pole magnetized in the circumferential direction, can be in the shape of a disk, a broken disk, or a drum.

(Example) Example 1j1- Figure 1 is a diagram showing the overall configuration of Example 1 of the present invention, and Figure 2 is a diagram showing the overall configuration of Example 1 of the present invention.
The figure is a cross-sectional view taken along line A-A. 1 is a magnetic head provided at the tip of a head arm 2, 3 is a magnetic disk, 4 is a head actuator consisting of a helad arm 2 and a voice coil 4a, and 5 is a motor drive circuit 6. An amplifier 7 for amplifying the control signal is a helad arm 2. A magnetic encoder consisting of a magnetized disk 8 and a magnetic sensor 9 fixed to the
0 is an amplifier that amplifies the detection signal of the magnetic sensor 9, 11 is a CPU, 12 is a D/A converter, 13 is a motor system servo circuit, 14 is a servo amplifier that receives the head signal as input, 15
is a V/T conversion burst demosimulator.

In FIG. 2, 16 is a disk clamp, 17 is a disk spacer, 18 is a bearing, 19 is a bearing spacer, 20
21 is a spindle motor, 21 is a preload disc spring, 22 is a deck, and 23 is a top cover.

The magnetized disk 8 is magnetized on the lower surface as shown in FIG. 3, and the magnetic sensor 9 includes four magnetoresistive elements R1, R1,
Rs and Ra are provided, and these magnetoresistive elements are arranged in a relationship with the magnetized surface of the magnetized disk 8 as shown in FIG.

Further, the four magnetoresistive elements are connected to form a bridge circuit as shown in FIG. 5, and the detection terminal e0 is connected to the amplifier 10.

The magnetized disk 8 is made of a non-magnetic material such as aluminum,
A thin magnetic film is formed on the lower surface and magnetized to form a large number of magnetic poles as shown in FIG.

The magnetic sensor 9 has a plurality of magnetoresistive elements (MR elements) deposited on a non-magnetic substrate such as glass.The MR elements are made of a thin film such as permalloy, and when the magnetic disk 8 rotates, a magnetic field is applied to the MR elements. changes, and the resistance of the MR element changes as shown in FIG.
rotation angle can be detected.

Therefore, when the bed actuator 4 operates and the head arm 2 rotates, the multi-pole magnetized magnetic disk 8
rotates, and the rotational angular displacement of the head arm corresponds to the magnetic disk 8.
and a magnetic encoder 7 consisting of a magnetic sensor 9.

The magnetized body is not disc-shaped as in Example 1, but
It may be in the shape of a disc, a fan, or a drum.

Figure 7 shows a second embodiment, in which a magnetized part 8a for a magnetic encoder is projected from a part of the head arm.

1. Figures 8 and 9 show Embodiment 3, in which a separate piece of magnetized body 81 is provided at the center of rotation of the head arm 2, multi-pole magnetization is performed on the side surface of the magnetized body 81, and a sensor is mounted opposite to it. Holder 24
A magnetic sensor 9 is provided which is fixed to the deck 22 via.

Figure 10 shows a fourth embodiment, in which a double-row magnetized body 82 having a gray code on the outer periphery is provided on the rotating shaft of the head arm.

In the figure, 91 is a magnetic sensor, and 101 is an amplifier.

1 Arashi 1 Figures 11 and 12 show the configuration of Example 5,
A disc-shaped multi-pole magnetized body 83 is provided at the lower part of the head arm 2, allowing for space saving and miniaturization.

〔Effect of the invention〕

According to the present invention, it is excellent as a means for solving all the problems of the above-mentioned method of recording positional information on a disk, and since the structure is simple and compact, it has the effect of reducing the inertia of the head arm.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing the overall configuration of Embodiment 1, FIG. 2 is a sectional view taken along line A-A in FIG. 1, FIGS. 3 and 4 are explanatory diagrams showing the configuration of a magnetic encoder, and FIG. 6 is a diagram showing the magnetic field change and resistance change curve of the magnetic encoder, FIG. 7 is a cross-sectional view of Example 2, FIG. 8 is a plan view of Example 3, and FIG. 9 is a sectional view taken along line B-B in FIG. 8, FIG. 10 is a perspective view of the main parts of Example 4, and FIG. 11 is Example 5.
FIG. 12 is a sectional view taken along the line C--C in FIG. 11. 1... Magnetic head 2... Head arm 3... Magnetic disk 4... Head actuator 4a... Voice coil 5... Amplifier 6... Motor drive circuit 7... Magnetic encoder 8... Magnetized disk 9... Magnetic sensor 10... Magnifier 11... CPU 12... D/A converter 13... Motor system servo circuit 14... Servo amplifier 15...・・V/T conversion burst demodulation”

Claims (3)

[Claims] (1) A data storage device having a rotary actuator, comprising a multipolar magnetized body centered on the rotation axis of the rotary actuator, and a magnetoresistive element for detecting rotational displacement of the actuator. Storage device. (2) The data storage device according to claim 1, wherein the magnetized body has a disk shape, a missing disk shape, a fan shape, or a drum shape. (3) The data storage device according to claim 1 or 2, wherein the magnetized body is magnetized to have a gray code.