JPS621177A - Magnetic head floating quantity testing device - Google Patents

Abstract

PURPOSE:To obtain the titled device which can be handled easily, is inexpensive and free from an error by depending on a measuring person, also to execute a test under the same condition as the case of an actual machine, and to improve the measuring accuracy, by applying a DC voltage between a magnetic head and a magnetic recording medium, generating a coulomb force, and executing the measurement of a floating quantity. CONSTITUTION:At first, the DC voltage applied to the magnetic head 1 is set to zero, a magnetic disk 2' is rotated at normal speed and the magnetic head 1 is floated, and thereafter, the voltage applied to the magnetic head 1 is increased gradually by a voltage regulator 42, and the applied voltage of the time when the magnetic head 1 contacts to the magnetic disk 2' is measured. Also, by using the conversion table of the applied voltage and the floating quantity prepared in advance, the floating quantity of the magnetic head 1 in a case the applied voltage is zero is derived. Or a voltage corresponding to the reference value (design value) of the floating quantity of the magnetic head 1 is applied, and by whether the magnetic head 1 and the magnetic disk 2' contact or not, the floating quantity of the magnetic head 1 is checked.

Description

DETAILED DESCRIPTION OF THE INVENTION [Summary] A magnetic head flying height measuring device for a magnetic recording device including a contact start-stop type magnetic disk device and a magnetic recording device equipped with a floating magnetic head.

Applying a DC voltage between the magnetic head and the magnetic recording medium,
A device configured to test the flying height of a magnetic head using Coulomb force.

[Industrial application field]

The present invention relates to a magnetic head flying height testing device for a magnetic recording device equipped with a flying type magnetic head.

For example, C is used as an external recording device for electronic needle counters.
SS The magnetic head of a contact start/stop type magnetic disk device is in contact with the magnetic disk surface while the magnetic disk is not rotating, but when the magnetic disk rotates, a magnetic head is generated between the magnetic head and the magnetic disk. It is designed to float above the magnetic disk surface due to the hydrodynamic effect of the resulting airflow.

For this reason, generally, a gimbal that holds the magnetic head so that it can rotate in two orthogonal axes parallel to the magnetic disk surface, a spring that acts to press the magnetic head against the magnetic disk surface, and a gimbal and/or a spring are used. The main component is an access arm that holds a magnetic head, and these structures including the magnetic head are called a magnetic head assembly.

A gimbal is usually made of an elastic thin metal plate along with a spring, and the magnetic nose rotates about the two axes against these elastic forces, and moves perpendicularly to the surface of the magnetic disk. .

As a result, the magnetic head flies above the magnetic disk surface while maintaining a certain attitude and flying height in a state where a balance is maintained between these elastic forces and the flying blade generated by the rotation of the magnetic disk.

However, the floating height is generally less than microns.

It is inevitable that hourly fluctuations and product-to-product variations occur due to the finishing conditions of the magnetic disk surface and magnetic head air bearing surface, the dimensional accuracy of the magnetic head gimbal, springs, etc.

For this reason, magnetic head assemblies are sometimes tested for flying height on a product-by-product basis before being incorporated into a magnetic disk drive.In this case, it is desirable that the flying height test be performed efficiently and with high accuracy. .

[Conventional technology]

Conventionally, a device applying optical interference method has been used to test the flying height of a magnetic head.

This device focuses on the mirror finish of the magnetic head air bearing surface, that is, the air bearing rail surface, and uses a glass disk as a simulated magnetic disk instead of a magnetic disk, and uses a glass disc as a simulated magnetic disk instead of a magnetic disk. The flying height is determined by observing interference fringes caused by interference with the object.

[Problem that the invention seeks to solve]

The apparatus having the above structure is complicated, requires skill to handle, and is expensive. Individual differences occur in measurement results depending on the measurer. Further, there are problems such as measurement errors caused by the difference between the magnetic disk and the glass disk.

Therefore, one object of the present invention is to provide a magnetic head flying height testing device that is easy to handle, inexpensive, and highly accurate.

[Means for solving problems]

FIG. 1 is a diagram showing the principle of the present invention, where 1 is a magnetic head, 2 is a magnetic recording medium, 3 is a spring that acts to press the magnetic head 1 against the magnetic recording medium 2, and 4 is a magnetic head 1.
A voltage applying circuit applies a DC voltage between the magnetic head 1 and the magnetic recording medium 2, and / is a detector that detects contact between the magnetic head 1 and the magnetic recording medium 2.

[Effect]

That is, a Coulomb force is generated by applying a DC voltage between the magnetic head 1 and the magnetic recording medium 2, and, for example, the applied voltage is gradually increased to reduce the force applied when the magnetic head contacts the magnetic recording medium 2. Depending on the voltage, the flying height when no voltage is applied is measured or compared with the design value.

〔Example〕

FIG. 2 is a configuration diagram of an embodiment applied to a magnetic disk device, in which 2' is a magnetic disk, 7 is an access arm, and 8
indicates an insulator that insulates between the spring 3 and the access arm 7.

The voltage application circuit 4 is composed of a DC power supply 41 and a voltage regulator 42 , and the magnetic disk 2 is grounded, and the output of the voltage regulator 42 is applied to the magnetic head 1 via the spring 3 .

The detector 5 includes a piezoelectric element 51 glued to the access arm 7.
and an amplifier 52 that amplifies the output thereof, and is configured to detect an impact when the magnetic head 1 and the magnetic disk 2' come into contact and display it on an indicator lamp (not shown).

That is, initially, the DC voltage applied to the magnetic heald 1 is set to zero, and the magnetic disk 2' is rotated at a normal speed to levitate the magnetic heald 2.

The voltage applied to the magnetic head 3 is gradually increased by the voltage regulator 42, the applied voltage when the magnetic head 1 contacts the magnetic disk 2' is measured, and a conversion table between the applied voltage and the flying height prepared in advance is calculated. use.

The flying height of the magnetic head 1 when the applied voltage is zero is determined.

Alternatively, a voltage corresponding to the reference value (design value) of the flying height of the magnetic head 1 is applied, and the magnetic head 1 and the magnetic disk 2 are
The flying height of the magnetic head is checked depending on whether or not .

〔Effect of the invention〕

As explained above, according to the present invention, compared to the conventional example,
It is easy to handle and inexpensive, there is no error caused by the measurer, and it can be tested under the same conditions as the actual machine, improving measurement accuracy.

1. The magnetic head flying height testing device of the present invention can also be used for accelerated life testing of magnetic disk drives. In the case of an accelerated life test, conventionally it was carried out by increasing the pressing force of the spring 3 and reducing the magnetic head flying surface, but by using the magnetic head flying height testing device according to the present invention, it is possible to Various acceleration conditions can be set simply by adjusting the applied voltage.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the principle of the present invention. FIG. 2 is a configuration diagram of the embodiment. Also in the figure. 1 is a magnetic head, 2 is a magnetic recording medium. 2' is a magnetic disk, 3 is a spring. 4 is a voltage application circuit, and 41 is a DC power supply. 42 is a voltage regulator, and 5 is a detector.

Claims (2)

[Claims] (1) An apparatus for testing the flying height of a magnetic head (1) that is pressed by a spring (3) and floats above the surface of a magnetic recording medium (2), the magnetic head (1) and the magnetic recording medium (2) A magnetic head comprising: a voltage application circuit (4) that applies a DC voltage between the magnetic head (1) and a detector (5) that detects contact between the magnetic head (1) and the magnetic recording medium (2). Floating height test device. (2) The magnetic field according to claim (1), wherein the detector (5) detects an impact caused by contact between the magnetic head (1) and the magnetic recording medium (2). Head flying height test device.