JPH04360082A - Magnetic disk device - Google Patents

Abstract

PURPOSE:To contrive accuracy of the device, a stable operation and improvement of the reliability by reading in a drive electric current value of a spindle motor at every load of a magnetic head and comparing this with the electric current stored by loading all heads. CONSTITUTION:A driving current value of a spindle 7 in a state that the magnetic head was loaded preliminarily is stored in a spindle motor driving current comparison circuit 10 and variation in the driving current value of the present spindle 7 is read out before the operation of the magnetic disk device and if the value is larger than driving current value preliminarily stored, the signal is so transmitted to a drive control circuit 9 of the device and operation of the device is worked. Hence with the wind loss generating when a slider 1 is loaded on the magnetic disk 2 that an electric current of the spindle motor increases, is detected and that the slider 1 is loaded is confirmed without a special load detecting sensor, etc.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic disk drive.

0002

2. Description of the Related Art Conventionally, magnetic heads used in magnetic disk drives for recording and reproducing data generally employ a flying slider type. In order to move the magnetic head to a desired position on the magnetic disk, a flexure is fixed to an arm that is movable in a direction transverse to the direction of rotation of the magnetic disk, and a floating slider is attached to the tip of the flexure. There is. Generally, a positive pressure slider is used as a floating slider. The operation will be explained below. When the magnetic disk is not operating, the slider is pressed against the magnetic disk surface by the load of the flexure, and even when the magnetic disk starts rotating, it remains in contact with the magnetic disk surface for a while. and,
When the rotation of the magnetic disk exceeds a certain number of rotations, the slider maintains a position where the positive pressure (upward force) generated on the slider by the air flow generated on the surface of the magnetic disk is balanced with the load due to the flexure acting on the slider. surface. And when the rotation speed of the magnetic disk slows down,
The positive pressure acting on the slider becomes smaller, and the slider comes into contact with the magnetic disk surface again due to the load of the flexure, and the magnetic disk stops. However, when such an operation is performed, wear particles and scratches are generated due to friction between the slider and the magnetic disk surface, and adhesion between the slider and the magnetic disk occurs.

In recent years, a method has been proposed in which a negative pressure type slider is used as a floating slider to levitate the slider and a magnetic disk without contact. A magnetic disk device using this negative pressure slider will be described below with reference to FIGS. 3 and 4. The direction perpendicular to the magnetic disk surface that approaches the magnetic disk is defined as a negative direction, and the direction that moves away from the magnetic disk is defined as a positive direction. In FIG. 3, reference numeral 5 denotes an arm that is movable in a direction across the data tracks recorded on the magnetic disk 2, and a flexure 3, which is constituted by a leaf spring and exerts a restoring force in the positive direction, is fixed to this arm. The slider 1 is attached to a flexure 3 via a gimbal 4 formed of a thin plate. Gimbal 4 is slider 1
Twisting occurs during the rolling motion and pitching motion of the slider 1, and the slider 1 flies while following the magnetic disk 2. An external actuator 6 is fixed to the arm 5 and operates to apply a negative load to the flexure 3 to levitate the slider 1 above the surface of the magnetic disk 2. A spindle 7 rotates the magnetic disk 2.

[0004] The operation of the magnetic disk device configured as described above will be explained below with reference to FIGS. 4(A), (B), and (C). In FIG. 4A, after the number of rotations of the magnetic disk 2 becomes constant, the external actuator 6 is operated to apply a negative load to the flexure 3 to displace the slider 1 in a direction closer to the magnetic disk 2. When the flexure 3 is displaced to a certain extent, positive pressure begins to be generated on the slider 1. This state is shown in FIG. 4(B). At this time, the surfaces of the slider 1 and the magnetic disk 2 are kept almost parallel, and even if the magnetic disk 2 vibrates or the arm 5 vibrates, the slider 1 follows the magnetic disk 2. I come to do it. As the flexure 3 further displaces, the positive pressure applied to the slider 1 gradually increases.
On the other hand, when the slider 1 and the magnetic disk 2 approach to a certain distance, negative pressure is generated in the slider 1. The slider 1 is attracted to the magnetic disk 2 by the negative pressure generated on the slider 1, and when the negative pressure generated on the slider 1 is balanced with the positive pressure and the restoring force in the positive direction of the flexure 3, the slider 1 is attracted to the magnetic disk 2. It levitates at regular intervals and enters the loading state. This is the state shown in FIG. 4(C).

[0005]

However, in the conventional configuration, the distance between the slider 1 and the magnetic disk 2 varies due to assembly errors when assembling each component, and the restoring force of the flexure 3 in the positive direction varies. Due to variations in the load applied by the external actuator 6 to the flexure 3, etc., the magnetic disk device may enter an operating state without the slider 1 being loaded. If the slider 1 is not loaded, the flexure 3 becomes cantilever-like, so when the magnetic disk drive enters the operating state and the slider 1 is sought, the slider 1 comes into contact with the magnetic disk 2, damaging the magnetic disk 2 and making the data unreliable. However, there was a problem in that the magnetic disk drive itself became unusable.

The present invention has been made to solve the above-mentioned conventional problems, and an object of the present invention is to provide a magnetic disk device that operates safely even if the balance of forces applied to a slider changes when the slider is loaded.

[0007]

[Means for Solving the Problem] In order to achieve this objective, the spindle drive current value with the magnetic head loaded is memorized in advance, and the current spindle drive current value is stored before operating the magnetic disk drive. Changes in the drive current value are read, and if the drive current value is greater than or equal to a pre-stored drive current value, a signal to that effect is sent to the drive control means of the magnetic disk drive to start operating the magnetic disk drive.

[0008]

[Operation] With this configuration, it is possible to detect a change in the current of the magnetic disk drive means by windage loss caused by the negative pressure slider floating above the magnetic disk.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a side view of a magnetic disk drive according to an embodiment of the present invention. Reference numeral 1 is a slider, 2 is a magnetic disk, 3 is a flexure, 4 is a gimbal, 5 is an arm, 6 is an external actuator, and 7 is a spindle, and these structures are the same as before. 8 is an external actuator control circuit that controls the operation of the external actuator 6;
is a magnetic disk device operation control circuit that controls the operations of the spindle 7 and arm 5. Reference numeral 10 denotes a spindle motor drive current comparison circuit that compares the current drive current value of the spindle motor with a reference current value stored in advance, and the reference current value is determined as follows. When the slider 1 is loaded onto the magnetic disk 2, windage loss occurs and the drive current of the spindle motor increases. This is because the rotational speed of the spindle motor is controlled so as not to drop due to windage loss due to the loading of the slider 1. Therefore, the relationship between the number of loaded magnetic heads and the spindle motor drive current value is as shown in Figure 2, so check in advance the spindle motor drive current value when all the magnetic heads of the magnetic disk drive are loaded. If, as shown in the figure, the current value that is immediately before the drive current value at this time, at which it can be determined that all the magnetic heads are loaded, is selected as the reference current value, then the current drive current value of the spindle motor will be the same as the reference current value. If the value is greater than or equal to this value, it can be determined that all the magnetic heads of the magnetic disk device are loaded and in a constant flying state.

The operation of the magnetic disk device configured as described above will be described below. First, when the power is turned on, the arm 5 operates in response to a signal from the magnetic disk device operation control circuit 9 to move the slider 1 to a predetermined loading position, and then the magnetic disk 2 starts rotating by the spindle 7. At the same time, the spindle motor drive current value is input to the spindle motor drive current comparison circuit 10. When the rotational speed of the magnetic disk 2 becomes constant, the external actuator 5 loads the slider 1 onto the magnetic disk 2. When the spindle motor drive current value exceeds the reference current value stored in advance in the spindle motor drive current comparison circuit 10, the spindle motor drive current comparison circuit 10 sends a signal S1 to the magnetic disk drive operation control circuit 9. If the spindle motor drive current value does not exceed the reference current value even after the load operation is completed, the spindle motor drive current comparison circuit 10 sends a signal S2 to the external actuator control circuit 8. The external actuator control circuit 8 to which the signal S2 is input returns the external actuator 6 to the state before operation, and then performs the loading operation again. This operation is repeated until the spindle motor drive current value input to the spindle motor drive current comparison circuit 10 becomes equal to or greater than the reference current value, and when the drive current value becomes equal to or greater than the reference current value, the spindle motor drive current is compared. The circuit 10 sends a signal S1 to the magnetic disk drive operation control circuit 9. The magnetic disk device starts normal recording/reproducing operations by the operation of the magnetic disk device operation control circuit 9 to which the signal S1 is input.

As described above, in this embodiment, windage loss occurs when the slider 1 is loaded onto the magnetic disk 2, and as a result of the windage loss, the rotational speed of the spindle motor decreases, so that the flow to the spindle motor is reduced. Since it is possible to detect that the current increases and confirm that slider 1 is loaded, there is no need to provide a special load detection sensor, etc., and data recording and recording is possible when slider 1 is not loaded. Since no reproduction is performed, the slider 1 and the magnetic disk 2 do not come into contact with each other.

0012

Effects of the Invention The present invention reads changes in the driving current value of the spindle motor that rotates the magnetic disk every time the magnetic head loads, and after loading all the magnetic heads of the magnetic disk device in advance, reads and stores the change. By providing a means for comparing the drive current value with the previously set drive current value,
The magnetic disk device starts operation after confirming that all magnetic heads of the magnetic disk device are loaded correctly, so even if the load applied to the slider changes during loading and the slider is not loaded correctly, it can be corrected. By loading the information, the magnetic disk device can be operated accurately and safely, and reliability can be improved.

[Brief explanation of the drawing]

FIG. 1 is a side view showing a magnetic disk device according to an embodiment of the present invention.

[Figure 2] Graph showing the relationship between the drive current value of the spindle motor and the number of loaded magnetic heads

[Fig. 3] A perspective view showing a magnetic head support device of a magnetic disk device.

FIG. 4 (A) is a side view showing the movement of the magnetic head support device; (B) is a side view showing the movement of the magnetic head support device; FIG.
is a side view showing the movement of the magnetic head support device.

[Explanation of symbols]

1 Slider 2 Magnetic disk 3 Flexure 4. Gimbal 5 Arm 6 External actuator 7 Spindle 8 External actuator control circuit 9 Magnetic disk device operation control circuit

Claims (1)

[Claims] 1. A magnetic disk, a driving means for rotationally driving the magnetic disk, a negative pressure slider having an electromagnetic transducer and facing the magnetic disk, and a negative pressure slider positioned at a predetermined position on the magnetic disk. a moving means for moving the negative pressure slider toward the magnetic disk; a loading means for bringing the negative pressure slider closer to the magnetic disk; and a current change in the driving means caused by windage when the negative pressure slider is levitated above the magnetic disk. What is claimed is: 1. A magnetic disk drive comprising: a detecting means for detecting, and performing a recording/reproducing operation when the detecting means detects a change in current exceeding a predetermined value.