JPS6259389B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic disk device that prevents overloading of a magnetic disk rotation motor and damage to the magnetic disk and magnetic head due to sticking of the magnetic disk and magnetic head.

In magnetic disk devices, in order to maintain a constant gap between a magnetic disk that rotates at high speed and a magnetic head in contact with it, we focus on the lift force generated on the magnetic head due to the hydrodynamic action between them. A widely used method is to balance the lifting force with the pressing force of a spring or the like. Recently, as the capacity, speed, and miniaturization of magnetic disk devices have increased, there has been an increasing demand for increased recording density. The gap between the head and the head is now smaller. For example, when the linear velocity of the magnetic disk is 30 m/s, a pressing force of 6 g is applied to maintain the gap between the magnetic disk and the magnetic head at 1 μ. Assuming that the area of the magnetic head surface is 3 mm ² , this pressing force reaches 200 g/cm ² per unit area. In addition to this, the surfaces of the magnetic disk and magnetic head both began to have a mirror finish. For these reasons, contact
In start-stop (CSS) type magnetic disk drives, when the magnetic disk remains in contact with the magnetic head for a long period of time, a so-called attraction phenomenon occurs between the magnetic disk and the magnetic head. This is a major cause of making it difficult to start up the magnetic disk device or damaging the magnetic disk and magnetic head. Until now, various types of magnetic disk devices have been proposed that are equipped with means to solve these problems, but most of them have the disadvantages of having complex structures, being expensive, and lacking in reliability. .

The present invention was made in response to the current situation, and its purpose is to have a simple and inexpensive structure, and also to be able to release the adhesion between the magnetic disc and the magnetic head by a highly reliable means. The purpose of the present invention is to provide a magnetic disk device.

In order to achieve the above object, the present invention provides a contact start/stop type magnetic head in which the magnetic head slides on the magnetic disk when the magnetic disk starts and stops rotating. The magnetic disk device is configured to cause the radial current of the magnetic disk to vibrate minutely at the start, and when causing the magnetic head to vibrate minutely, the driving force of the magnetic head is controlled so that it is weak at first and gradually becomes stronger. It was designed to do so.

The present invention also provides a magnetic disk device that employs a contact start/stop method in which a magnetic head slides on a magnetic disk when the magnetic disk starts and stops rotating, The relationship between the magnetic disc and the magnetic head is established by causing the magnetic head to minutely vibrate, monitoring the current flowing through the magnetic head drive motor during the minute vibration, and detecting a sudden decrease in the motor current. It is determined that the adsorption is released, and the minute vibrations are stopped.

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, 1 is a magnetic head, 2 is a magnetic disc, and 3 holds the magnetic head 1 and presses it against the magnetic disc 2, so that the rotation of the magnetic disc 2 causes a magnetic force to be generated on the magnetic head 1. Arm with elastic force necessary to balance lifting force, 4 is arm 3
A servo motor controls the position of the magnetic head 1 in the radial direction of the magnetic disc 2 via a servo motor, 5 a rotary motor that rotates the magnetic disc 2, and 6 a control circuit that controls the servo motor 4 and the rotary motor 5. be. 1st
In the figure, the main parts of the present invention mainly relate to a servo motor 4 and a part of a control circuit 6. Second
The figure is a block diagram of the related parts, where 7 is an irregular signal generator that obtains a signal for applying vibrations whose frequency and/or amplitude changes irregularly to the magnetic head via the servo system described later, and 8 is a sensor described later. A switch 9 switches between the signal generated by the irregular signal generator 7 and the magnetic head positioning signal A in accordance with the detection signal of the servo amplifier 9, which forms a servo system together with the servo motor 4 and amplifies the control signal. 10 is a sensor that detects the load current of the servo motor 4. In the above configuration, the switch 8 initially cuts off the magnetic head positioning signal A and accepts the signal generated by the irregular signal generator 7, and releases the fixation between the magnetic head 1 and the magnetic disk 2. The startup of the magnetic disk device is performed as follows. Irregular signal generator 7
The irregular signal generated by the servo amplifier 9 is amplified by the servo amplifier 9 and applied to the servo motor 4. For this reason, the servo motor 4 generates vibrations whose frequency and/or vibrations vary irregularly, which are transmitted to the magnetic head 1 via the arm 3. As a result, the magnetic head 1
When the fixation of the magnetic disk 2 is released, the load current of the servo motor 4 decreases rapidly. When the sensor 10 detects this, the switch 8 is switched to cut off the signal from the irregular signal generator 7, connect the magnetic head positioning signal A to the servo amplifier 9, and start the rotation of the rotary motor 5. Hereinafter, we will move on to the normal operation of the magnetic disk device. The signal generated by the irregular signal generator 7 varies depending on the magnetic disk device, and is generated by the servo amplifier 9 and the signal so that the signal is initially weak and gradually increases in strength so as not to cause undue force on the fixed magnetic head. It is determined experimentally while considering the dynamic characteristics of the servo system including the servo motor 4 and the arm 3.
In addition, it goes without saying that certain frequencies should be excluded in order to avoid damage due to resonance in each part of the mechanism. In this way, when the magnetic head 1 is vibrated in the radial direction of the magnetic disc 2, it simultaneously passes through the vicinity of the connection point between the arm 3 and the magnetic head 1, is parallel to the magnetic disc 2, and is parallel to the radial direction of the magnetic disc 2. Since rotational vibrations centered on orthogonal straight lines (perpendicular to the plane of the paper in FIG. 1) are applied to the magnetic head 1, this is effective in releasing the fixation between the magnetic head 1 and the magnetic disc 2.

As explained above, according to the present invention, when the magnetic head is caused to minutely vibrate at the start of rotation of the magnetic disk, the driving force of the magnetic head is controlled so that it is weak at first and gradually increases in strength, so that the magnetic disk and the magnetic It becomes possible to safely and easily release the adhesion (adsorption) caused by adsorption of the head without destroying the magnetic head.

Further, according to the present invention, the magnetic head is slightly vibrated when the magnetic disc starts rotating, and the current flowing through the magnetic head drive motor during the minute vibration is monitored.
Fixation (adsorption) between the magnetic disc and the magnetic head by detecting a sudden decrease in motor current
Since it is determined that the magnetic disc and the magnetic head have been released and the minute vibrations are stopped, it is possible to accurately know that the adhesion between the magnetic disc and the magnetic head has been released, and the operation of the magnetic disk device can be started quickly. I can do it.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of an embodiment of the present invention, and Fig. 2 is a block diagram of its main parts, where 1 is a magnetic head, 2 is a magnetic disk, 3 is an arm, 4 is a servo motor, and 5 is a rotating part. 6 is a control circuit, 7 is a random signal generator, 8 is a switch, 9 is a servo amplifier, and 10 is a sensor.

Claims (1)

[Scope of Claims] 1. A contact start/stop type magnetic head in which the magnetic head slides on the magnetic disk when the rotation of the magnetic disk starts and stops. The magnetic disk device is configured to cause minute vibrations in the radial direction of the magnetic head, and the driving force of the magnetic head is controlled such that when the magnetic head is caused to minutely vibrate, it is weak at first and gradually becomes stronger. Features of magnetic disk device. 2. A magnetic disk device that employs a contact start-stop method in which a magnetic head slides on a magnetic disk when the magnetic disk starts and stops rotating, and the magnetic head slides when the magnetic disk starts rotating. The adhesion between the magnetic disc and the magnetic head is released by making a minute vibration, monitoring the current flowing through the magnetic head drive motor during the minute vibration, and detecting a sudden decrease in the motor current. 1. A magnetic disk device characterized in that it determines that a magnetic disk is a magnetic disk, and stops minute vibrations.