JPS63187477A - Magnetic head controller - Google Patents

Abstract

PURPOSE:To set the floating quantity of a magnetic head to a proper value by supplying a driving voltage decided based on a floating quantity detected by a floating quantity detection means to a piezoelectric member from a piezoelectric control means so as to apply the driving control of the piezoelectric member. CONSTITUTION:An output voltage signal outputted from a magnetic head 10 is amplified by an amplifier 11 and outputted to a floating quantity detection circuit 12, which detects the floating quantity of the magnetic head 10 to a disk 23 and outputs its detecting signal. A piezoelectric control circuit 13 obtains an error to a proper floating quantity decided in advance and applies the driving voltage in response to the error to a piezoelectric film 14. The piezoelectric film 14 is, e.g., elongated to drive a head arm 20 to approach the core slider 22 of the magnetic head 10 to the disk 23. Thus, the floating quantity of the magnetic head 10 with respect to the disk 23 is set to a proper value based on a proper output voltage as a reference and the proper floating quantity of the magnetic head 10 is always ensured.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention particularly relates to a magnetic head control device used in a hard disk drive.

(Prior Art) Conventionally, in a hard disk drive, a magnetic head approaches a disk, which is a magnetic recording medium, and the magnetic head performs a read/write operation that magnetically records data on the disk and reproduces the data. . This lead/
In a write operation, the flying height of the magnetic head relative to the disk must be set to an appropriate value.

The flying height of a magnetic head is determined by the shape of the disk contact surface of a core slider that constitutes the magnetic head and the magnitude of the load on the core slider.

Therefore, the accuracy of the flying height of the magnetic head depends on the manufacturing accuracy of the core slider and the stability of the spring structure of the suspension in the head support mechanism for generating the load. The shape of the core slider can be manufactured with relatively high precision, but the spring structure of the suspension is realized by giving the suspension a predetermined angle, so it is possible to obtain high-precision sustained stability and reproducibility. has its limits.

(Problems to be Solved by the Invention) In the conventional magnetic head support mechanism, since there is a limit to the accuracy of the spring structure of the suspension, it is difficult to set the flying height of the 7 Vitl air head with high precision. This is a major obstacle in achieving higher recording density in hard disk drives.

SUMMARY OF THE INVENTION An object of the present invention is to provide a magnetic head control device that can set the flying height of a magnetic head with respect to a disk with high precision in a hard disk device, thereby realizing a high recording density of the magnetic disk device. There is a particular thing.

[Structure of the Invention] (Means and Effects for Solving Problems) The present invention provides a piezoelectric member provided in a head support mechanism, a flying height detection means for detecting the flying height of a magnetic head, and a drive for the piezoelectric member. This is a magnetic head control device equipped with a piezoelectric υ+tin means for performing control.

The piezoelectric member is a member for driving the head support mechanism by expanding or contracting in response to a driving voltage, and adjusting the flying height of the magnetic head relative to the magnetic recording medium.

The flying height detection means is means for detecting the flying height based on the output voltage output from the magnetic head when reading data from the magnetic recording medium. The piezoelectric control means supplies a drive voltage determined based on the flying height detected by the flying height detection means to the piezoelectric member, and controls the drive of the piezoelectric member in order to set the flying height of the magnetic head to an appropriate value. It is a means.

Such a device makes it possible to adjust the operation of the head support mechanism and set the flying height of the magnetic head relative to the magnetic recording medium to an appropriate value.

(Example) The present invention will be described in detail below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of the magnetic head control m+ device of the same embodiment, FIG. 2 is a side sectional view showing the configuration of the head support mechanism of the same example, and FIG. 3 is a diagram of the magnetic head support mechanism. FIG. 3 is a plan view showing the configuration.

In FIG. 1, an amplifier 11 is a circuit that amplifies an output voltage signal output from the magnetic head 10, and is an amplifier that constitutes a read circuit of a hard disk device. As shown in FIGS. 2 and 3, the magnetic head 10 includes a core slider 22 attached via a gimbal 21 to the tip of a head arm (load arm) 20 that constitutes a suspension. The core slider 22 has a read/write coil and a read/write gap.

The flying height detection circuit 12 is a circuit that detects the flying height of the magnetic head 10 with respect to the disk (23 in FIG. 2) based on the output voltage signal output from the amplifier 11. Specifically, the flying height detection circuit 12 includes, for example, a circuit that averages the output voltage signal from the amplifier 11 and a detection signal (or data) corresponding to the flying height determined according to the averaged output voltage signal level. Equipped with an output circuit. The piezoelectric control circuit 13 outputs a drive voltage to the piezoelectric film 14 for setting the flying height of the magnetic head 10 to an appropriate value based on the detection signal output from the flying height detection circuit 12.

Specifically, the piezoelectric control circuit 13 includes, for example, a circuit that calculates an error between a flying height determined based on a detection signal and an appropriate flying height, and a table and a table storing drive voltage data for correcting the error. It is equipped with an A/D converter circuit that converts the drive voltage data read out from the converter into an analog voltage signal.

The piezoelectric film 14 is a piezoelectric element on a film made of polyfluoroethylene, for example, and has a characteristic of expanding or contracting in response to changes in the applied driving voltage. As shown in FIGS. 2 and 3, the piezoelectric film 14 is attached to a bent portion of the head arm 20, that is, a connecting portion with a fixing portion 24 for fixing the head arm 20 to the carriage.

Next, the operation of this embodiment will be explained. First, in the hard disk drive, when the disk 23 rotates, the core slider 22 of the magnetic head 10 is lifted from the C8S area of the disk 23 by the drive of the head arm 20, and a seek operation is performed to a predetermined track. magnetic head 10
performs a data reading operation from the disk 23 at a position having a predetermined flying height from the disk 23. The output voltage signal output from the magnetic head 10 is amplified by an amplifier 11 and then output to a flying height detection circuit 12.

The flying height detection circuit 12 detects the flying height of the magnetic head 10 with respect to the disk 23 based on the output voltage signal output from the magnetic head 10, and outputs the detection signal.

Here, the relationship between the output voltage level of the magnetic head 10 and the flying height can be measured experimentally in advance, and there is a characteristic that the output voltage level decreases almost linearly as the flying height increases. The piezoelectric control circuit 13 determines an error with respect to a predetermined appropriate flying height based on the detection signal from the flying height detection circuit 12, and applies a drive voltage to the piezoelectric film 14 according to the error.

The piezoelectric film 14 has a property of expanding (or contracting) in response to an increase (or decrease) in the drive voltage level, for example.

In response to the drive voltage output from the piezoelectric control circuit 13, the piezoelectric film 14 extends, for example, and drives the head arm 20, moving the core slider 22 of the magnetic head 10 toward the disk 2.
Close to 3. As a result, for example, the flying height of the magnetic head 10 is relatively reduced, and an appropriate flying height corresponding to an appropriate output voltage is set.

In this way, the flying height is detected based on the output voltage of the magnetic head 10, and the head arm 20 is driven using the piezoelectric film 14 so that the flying height becomes an appropriate value. As a result, the magnetic head 10 relative to the disk 23
The flying height can be set to an appropriate value based on an appropriate output voltage. Therefore, a suitable magnetic head 1
A flying height of 0 can always be ensured, and stable, reliable, and stable read/write operations can be realized.

In the same embodiment, the piezoelectric control circuit 13 is configured as a digital circuit having a table storing drive voltage data, but the piezoelectric control circuit 13 is not limited to this, and may be configured as an analog circuit having a comparator. . In this case, the comparator compares the detection signal (N pressure signal) from the flying height detection circuit 12 with a reference voltage corresponding to an appropriate flying height in advance, and outputs this error signal to the piezoelectric film 14 as a drive voltage. By repeating this operation until the error signal from the comparator becomes O, the flying height of the magnetic head 10 is set to an appropriate value.

[Effects of the Invention] As detailed above, according to the present invention, in a hard disk drive, the flying m of the magnetic head is set to an appropriate value corresponding to an appropriate output voltage, based on the output voltage from the magnetic head. be able to.

Therefore, even if the precision of a head support mechanism such as a suspension is somewhat low, the flying height of the magnetic head can be set with high precision.

This makes it possible to relatively reduce the flying height of the magnetic head and stabilize read/write operations on high-density disks, resulting in the realization of higher recording densities in hard disk drives. This is the result.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the structure of a magnetic head control device according to an embodiment of the present invention, FIG. 2 is a side sectional view showing the structure of a head support mechanism of the same embodiment, and FIG. 3 is a head diagram of the embodiment. FIG. 3 is a plan view showing the configuration of a support mechanism. 10...Magnetic head, 12...Flying height detection circuit, 1
3... Piezoelectric control circuit, 14... Piezoelectric film, 20
...Head arm, 22...Core slider, 23.
··disk.

Claims (1)

[Claims] a head support mechanism for setting the magnetic head at a predetermined position with respect to the magnetic recording medium; and a head support mechanism for setting the magnetic head at a predetermined position with respect to the magnetic recording medium; a flying height detection means for detecting the flying height of the head; a piezoelectric member provided at a predetermined position of the head support mechanism to adjust the flying height of the magnetic head by an expansion or contraction operation according to a driving voltage; Supplying a drive voltage determined based on the flying height detected by the flying height detection means to the piezoelectric member to set the flying height of the magnetic head to an appropriate value corresponding to an appropriate output voltage of the magnetic head. and piezoelectric control means for controlling the drive of the piezoelectric member.