JPH0421979A - Method and device for driving magnetic head - Google Patents

Abstract

PURPOSE:To prevent a magnetic head from being damaged by adsorbing a core slider onto the surface of a recording medium by displacing a negative pressure slider to be set at a second stable position, where force operated onto the negative pressure slider can be balanced with restoring force by positive pressure and negative pressure, when the rotating speed of the recording medium reaches the normal rotating speed. CONSTITUTION:When the rotation of the recording medium is stopped, the negative pressure slider is held at the first stable position (away from the surface of the recording medium by 100mum, for example) sufficiently separated from the recording medium surface where the positive pressure and the negative pressure is not operated. When the rotation of the recording medium is started, a signal is transmitted at suitable timing to impress a voltage to a piezoelectric element 22, and the surface of the piezoelectric element 22 on the recording medium side is displaced to be close to the recording medium surface. With this displacement, a spring arm 26 is elastically deformed, and the negative pressure slider 4 is displaced from the first stable position to the second stable position (away from the recording medium surface by 0.1mum, for example). When the negative pressure slider 4 is displaced to the second stable position, at this second stable position, the positive pressure and the negative pressure is operated onto the negative pressure slider 4, and the force composed of this negative and positive pressure is balanced with the elastic force (restoring force) of the spring arm 26.

Description

[Detailed Description of the Invention] Table of Contents Overview Industrial Field of Application Conventional Technology Problems to be Solved by the Invention Means for Solving the Problems Implementation Example Summary of Effects of the Invention Regarding the driving method and drive device for a magnetic head, the purpose is to improve the durability of the magnetic head and the recording medium, and the method includes applying positive pressure in the direction away from the recording medium when the head is located near the recording medium, and A negative pressure slider, on which a negative pressure in a direction approaching the recording medium acts in accordance with the rotational speed of the recording medium, is held at a first stable position where the positive pressure and negative pressure do not act; A restoring force corresponding to the displacement from the stable position is applied to the negative pressure slider, and when the recording medium starts rotating and the rotation speed reaches a steady rotation speed, the positive pressure and negative pressure are The negative pressure slider is moved from the first stable position to the second stable position so that the negative pressure slider is located at a second stable position where the force acting on the negative pressure slider and the restoring force are balanced. The structure is configured so that it is displaced.

INDUSTRIAL APPLICATION FIELD The present invention relates to a method and device for driving a magnetic head in a direction perpendicular to the surface of a recording medium in a magnetic disk device.

For example, a magnetic disk drive used as a storage device for a computer writes information in the form of binary numbers necessary for computer operations to a specified position on the recording medium according to the principle of magnetic recording, and vice versa. It functions to read information written at a specified location on a recording medium from the recording medium. Writing information to or reading information from a specified position on a recording medium is performed by moving a magnetic head along a plane parallel to the surface of the recording medium. In this type of magnetic disk device, the gap between the core gap of the magnetic head and the surface of the recording medium directly affects performance such as recording density, and from this point of view, it is better for the gap to be as small as possible. This is a technique for moving the magnetic head along a plane parallel to the recording medium surface while keeping the gap between the core gap of the magnetic head and the recording medium surface 5 as small as possible. There is one in which a core slider of a magnetic head is made to float through an air layer. In this case, when the recording medium starts to accelerate or stops and decelerates, the gap is extremely small, so the core slider tends to come into contact with the surface of the recording medium, and there is concern that the durability of the magnetic head or the recording medium will deteriorate. . Therefore, it is desired to improve the durability of magnetic heads and recording media.

Prior Art FIG. 7 shows the configuration of a conventional magnetic head for a magnetic disk device. FIG. 5A is a bottom view of the magnetic head viewed from the recording medium side, and FIG. 1B is a side view thereof. This magnetic head consists of a spring arm 42 made of an elastic body connected to a horizontal drive mechanism (not shown), a gimbal 44 provided on the free end side of the spring arm 42, and a core slider 46 attached to the gimbal 44. It is configured. When writing information to or reading information from a recording medium, the magnetic head is driven along a plane parallel to the recording medium surface by the horizontal drive mechanism to move the magnetic head to a specified position on the recording medium surface. information can be written or read.

FIG. 8 is a perspective view of the core slider with the surface facing the recording medium facing upward. 46a is the base of the core slider, 46
b is a flat air bearing surface from which both edges of the base 46a in the recording medium movement direction protrude, and 46c is a gap portion inclined at an appropriate angle (for example, 15') with respect to the air bearing surface 46b. Although a core gap for writing and reading information is not shown, the core gap is usually formed so as to be located on the same plane as the air bearing surface 46b. The core slider 46 is inserted into the air bearing surface 4 from above the recording medium being rotationally driven.
6b and the gap 46G facing downward and pressed against the surface of the recording medium by its own weight or the elastic force of the spring arm.
A gap portion 46c located on the first stream side in the recording medium surface movement direction.
The air that has entered between the air bearing surface 46b and the recording medium surface is compressed, and an air film is constantly formed between the air bearing surface 46b and the recording medium surface. The core slider is positioned at a position where the forces are balanced, and a required minute gap is formed between the core gap and the surface of the recording medium.

FIG. 9 shows the force acting on the core slider floating above the recording medium surface. In the illustrated example, the elastic force of the spring arm is used to press the core slider against the recording medium surface, and the weight of the core slider is ignored. Reference numeral 48 denotes a pressing force exerted downwardly by the core slider 46 from the head arm 50 to which the spring arm is fixed, and 52 interposes between the recording medium surface 54 and the air bearing surface 46b and gap portion 46C of the core slider. The core slider 46 represents a floating blade that is pushed upward by an air spring of an air film. The pressing force 48 is determined according to the spring constant of the spring arm and the amount of deformation of the spring arm, and the floating blade 52 is determined depending on the shape of the core slider 46, the moving speed of the recording medium surface 54 (rotational speed of the recording medium), and the floating blade 52. It is decided according to the amount etc. Therefore, by adjusting the spring constant of the spring arm and the shape of the core slider,
A required flying height (for example, 0.1 to 0.5 μm) can be obtained.

Problems to be Solved by the Invention By the way, the balance of forces acting on the slider explained with reference to FIG. 9 is when the recording medium is rotating steadily. For example, when the recording medium is stopped, no floating blade is generated by the air spring, and the core slider is in contact with the recording medium.

Furthermore, when the rotational speed increases and decreases when the recording medium starts and stops rotating, the floating blade becomes unstable and the core slider tends to come into contact with the recording medium. For this reason, in this type of so-called CSS (Contact Start Stop) type magnetic disk drive, damage to the core slider or recording medium is likely to occur, and in the worst case, the core slider may stick to the surface of the recording medium and the magnetic head may be damaged. There was a problem with it being damaged.

Therefore, an object of the present invention is to improve the durability of a magnetic head and a recording medium.

Means for Solving the Problems In view of the above-mentioned technical problems, the present invention provides a method and a driving device for driving a magnetic head in a direction perpendicular to the surface of a recording medium.

FIG. 2 is a perspective view of the negative pressure slider used in the practice of the present invention, with the surface facing the recording medium facing upward. This negative pressure slider 4 is formed with a U-shaped air bearing surface 4a shown with diagonal lines, and a gap portion 4b formed on the upstream side of the air bearing surface 4a in the direction of movement of the recording medium surface. . In the following explanation, the moving direction of the recording medium surface relative to the negative pressure slider is referred to as the length direction of the negative pressure slider, and the direction parallel to the recording medium surface and perpendicular to the length direction is referred to as the width direction of the negative pressure slider. .

FIG. 3 is a diagram showing the pressure distribution in the length direction of the air film generated in the vicinity of the negative pressure slider. The horizontal axis represents the position in the length direction of the negative pressure slider (the right side is the downstream side in the direction of movement of the recording medium surface), and the vertical axis represents the pressure. On the pressure axis, the (+) side indicates that positive pressure is occurring in the direction away from the recording medium, and the (-) side indicates that negative pressure is occurring in the direction toward the recording medium. A curve 12 indicated by a broken line is the pressure distribution in the vicinity of the negative pressure slider 4 in the plane including the A-A cross section and the C-C cross section of the widthwise end of the negative pressure slider 40, and is indicated by a solid line. A curve 14 is a pressure distribution in the vicinity of the negative pressure slider 4 on a plane including the BB cross section at the approximate center in the width direction of the negative pressure slider 40 .

Further, point E on the horizontal axis indicates the position of the upstream end of the air bearing surface 4a in the direction of movement of the recording medium surface, and point F indicates the position of the downstream end of the air bearing surface 4a. In the vicinity of the A-A cross section and the C-C cross section, as in the case of the conventional slider,
Only the positive pressure that reaches the maximum pressure at point E is acting.

On the other hand, in the vicinity of the -B cross section, which is unique to negative pressure sliders, the maximum positive pressure is reached at point E, but the pressure rapidly decreases from there toward the downstream side in the direction of movement of the recording medium surface, and negative pressure is applied. I come to do it.

For reference, the operation when a negative pressure slider is generally used will be explained with reference to FIG. In the figure, numeral 16 shows the relationship between the flying height and the rotational circumferential speed of the recording medium in a conventional slider, and 18 shows the same relationship in a negative pressure slider. In conventional sliders, the flying height increases as the circumferential speed increases, whereas with negative pressure sliders, the flying height increases as the circumferential speed increases in areas where the circumferential speed is low. However, in a region where the circumferential speed is high, the flying height is almost constant regardless of the circumferential speed. This effect occurs because in the negative pressure slider,
This is thought to be because the circumferential velocity dependence of the floating blade, which is given as an integral value of positive pressure, and the circumferential velocity dependence of suction force, which is given as an integral value of negative pressure, are different.

By the way, positive pressure and negative pressure act on the negative pressure slider only when the negative pressure slider is located near the recording medium.If the negative pressure slider is not located near the recording medium, positive pressure and negative pressure act on the negative pressure slider. and negative pressure does not work. Based on this fact,
When the recording medium stops rotating, the negative pressure slider is kept sufficiently away from the recording medium, and only when the recording medium is steadily rotating, a predetermined minute gap is formed between the negative pressure slider and the recording medium. It becomes possible to perform good write and read operations. The present invention embodies this idea.

FIG. 1 is a diagram showing the principle of the present invention, and shows the configuration of a magnetic head driving device in a direction perpendicular to the surface of a recording medium. When this device is located near the recording medium 2, positive pressure in the direction away from the recording medium 2 and negative pressure in the direction toward the recording medium 2 act according to the rotational speed of the recording medium 2. Negative pressure slider 4;
negative pressure slider holding means 6 for holding the slider at a first stable position where the positive pressure and negative pressure do not act so that a restoring force is applied according to the displacement from the stable position, and the recording medium 2 starts to rotate. When the rotational speed reaches a steady rotational speed, the negative pressure slider 4 is located at a second stable position where the force acting on the negative pressure slider 4 due to the positive pressure and the negative pressure and the restoring force are balanced. The negative pressure slider driving means 8 displaces the negative pressure slider 4 from the first stable position to the second stable position.

Further, a method for driving a magnetic head according to the present invention is a method for driving a magnetic head in a direction perpendicular to the surface of a recording medium, comprising:
A negative pressure slider 4 that, when located near the recording medium 2, applies positive pressure in the direction away from the recording medium 2 and negative pressure in the direction toward the recording medium 2, depending on the rotational speed of the recording medium 2. is held at a first stable position where the positive pressure and negative pressure do not act, and a restoring force corresponding to the displacement from the first stable position is applied to the negative pressure slider 4, When the rotation speed of the recording medium 2 starts to reach a steady rotation speed, the recording medium 2 reaches a second stable position where the force acting on the negative pressure slider 4 due to the positive pressure and the negative pressure and the restoring force are balanced. The negative pressure slider 4 is displaced from the first stable position to the second stable position so that the negative pressure slider 4 is positioned.

According to the present invention, the negative pressure head is held at the first stable position when the recording medium stops rotating, so that the negative pressure head is prevented from coming into contact with the recording medium and being damaged. Ru. Furthermore, when the rotational speed of the recording medium reaches a steady rotational speed, a second stable state is reached in which the force acting on the negative pressure slider due to positive pressure and negative pressure is balanced by the restoring force according to the displacement from the first stable position. Since the negative pressure slider is located at this position, by specifying the magnitude relationship of the answers so as to obtain a second stable position where a minute gap is formed between the negative pressure slider and the recording medium, Good write and read operations are achieved. In addition, in order for the second stable position to exist, the restoring force acting on the negative pressure slider in the direction of the levitation force and the force acting on the negative pressure slider due to positive pressure and negative pressure must be balanced at the second stable position. First, the forces acting on the negative pressure slider due to positive pressure and negative pressure are required to act in the direction of suction force. In this respect, it differs from the general usage of negative pressure sliders in which the force acting on the negative pressure slider due to positive pressure and negative pressure acts in the direction of the levitation force. By adjusting the ratio of the surface to the total bottom surface and the steady rotation speed of the recording medium, the force acting on the negative pressure slider due to positive pressure and negative pressure can be made to act in the direction of the suction force.

Example The present invention will be explained in detail below.

FIG. 5 is an exploded perspective view of a magnetic head constructed to which the present invention is applied. 20 is a head arm connected to a horizontal drive mechanism (not shown), and a hole 20a formed in this head arm 20 has a piezoelectric element 22 that can be deformed in a direction perpendicular to the surface of the recording medium according to an input electric signal. is embedded and fixed. A spring arm 2 made of an elastic body is attached to the lower surface of the head arm 20 via a spacer 24.
6 is fixed at one end. The head arm 20 and the spacer 24 are fixed by screws, and the spacer 24
The spring arm 26 is fixed by laser welding. 26a is a dowel protrusion that protrudes from the upper surface side of the spring arm 26, and this dowel protrusion 26a is connected to the piezoelectric element 22.
By contacting the lower surface side of the piezoelectric element 22
The spring arm 26 can be elastically deformed by the deformation. A gimbal 28 is fixed to the lower surface of the free end side of the spring arm 26 by laser welding, and the gimbal 28 is formed by punching and bending a thin metal plate. The negative pressure slider 4 is fixed with adhesive to the lower surface side of the tongue-shaped piece 28a of the gimbal left after the punching process.

According to such a configuration of the gimbal 28, the tongue-shaped piece 28a
Based on the twisting deformation and deflection deformation of the negative pressure slider 4, it becomes possible to hold the negative pressure slider 4 rotatably within a minute angle range around two mutually orthogonal axes on a plane approximately parallel to the recording medium surface. , regardless of manufacturing errors such as undesired inclination of the negative pressure slider 4 in a particular direction, positive pressure and negative pressure are stably generated and the air bearing surface of the negative pressure slider and the recording medium surface at the second stable position are connected. It becomes possible to obtain a good minute gap between the two.

The head arm 20 is a recording medium in which the negative pressure slider 4 is in a first stable position when the spring arm 26 is not elastically deformed due to the deformation of the piezoelectric element 22, that is, in which positive pressure and negative pressure do not act on the negative pressure slider 4. It is provided at a predetermined distance from the surface of the recording medium so as to be located at a position sufficiently away from the surface of the recording medium. Thereby, the negative pressure slider 4 can be held at the first stable position so that a restoring force is applied depending on the displacement from the stable position.

The negative pressure slider driving means including the piezoelectric element 22 includes, in addition to the piezoelectric element 22, a control circuit for adjusting a signal sent to the piezoelectric element 22. The driving operation of the magnetic head in this embodiment based on the operation of this control circuit will be explained with reference to FIG. In the figure, the vertical axis is the flying height of the slider, and the horizontal axis is the elapsed time. A solid line 30 represents the change over time in the flying height of the negative pressure slider 4 in this embodiment, and a broken line 3
2 is a conventional slider that is not driven in the direction perpendicular to the surface of the recording medium (regardless of whether it is a negative pressure slider or not).
It shows the change in floating height over time.

When using a conventional slider, the slider contacts the surface of the recording medium when the recording medium stops rotating, and the flying height is not determined when the rotational speed of the recording medium increases or decreases, so there is a risk of damage to the magnetic head or the recording medium. As mentioned above, there is.

In this embodiment, the negative pressure slider is driven and controlled in the direction perpendicular to the surface of the recording medium as follows.

First, when the rotation of the recording medium is stopped, the negative pressure slider is held at a first stable position (for example, a position 100 μm from the recording medium surface) that is sufficiently distant from the recording medium surface where positive pressure and negative pressure do not act. . When the recording medium starts to rotate, a signal is sent to apply a voltage to the piezoelectric element 22 at an appropriate timing, and the surface of the piezoelectric element 22 on the recording medium side is displaced so as to approach the recording medium surface. Accordingly, the spring arm 26 is elastically deformed, and the negative pressure slider 4 is displaced from the first stable position to the second stable position (for example, a position 0.1 μm from the recording medium surface). When the negative pressure slider 4 is displaced to the second stable position, positive pressure and negative pressure act on the negative pressure slider 4 in this second stable position, and the force due to this positive pressure and negative pressure and the elastic force of the spring arm 26 (Resilience)
will be balanced. Therefore, after the time when the recording medium starts to rotate at a steady rotational speed, the voltage application to the piezoelectric element 22 is stopped, and the contact state between the piezoelectric element 22 and the dowel protrusion 26a of the spring arm is released. However, the negative pressure slider 4 is located in the second stable position. When the rotational speed of the recording medium is decreased from the steady rotational speed in order to stop the recording medium, the suction force acting on the negative pressure slider 4 due to the positive pressure and negative pressure in the direction of the surface of the recording medium gradually decreases. Therefore, the restoring force of the spring arm 26 is stronger than this suction force, and the negative pressure slider 4
is displaced to the original first stable position by the restoring force.

As described above, according to this embodiment, the negative pressure slider does not come into contact with the surface of the recording medium, thereby preventing damage to the magnetic head and the recording medium. Furthermore, when the recording medium is rotating at a steady rotational speed, the negative pressure slider can be positioned at a second stable position at an extremely small distance from the surface of the recording medium, allowing for good writing and reading of recorded information. becomes possible.

In this embodiment, the negative pressure slider driving means includes a piezoelectric element, but the present invention is not limited to this configuration. For example, the negative pressure slider may be driven in a direction perpendicular to the surface of the recording medium using fluid pressure such as air pressure.

Furthermore, in this embodiment, a winchiesta type structure is used as the basic support system for the slider.
A Watrous type or an in-line type may be used.

As described in detail, according to the magnetic head driving method or drive device of the present invention, the slider does not come into contact with the surface of the recording medium when the recording medium stops rotating, so the durability of the magnetic head and the recording medium is improved. It has the effect of improving sexual performance.

[Brief explanation of drawings]

Fig. 1 is a diagram showing the principle of the present invention, Fig. 2 is a perspective view of a negative pressure slider used to implement the present invention, Fig. 3 is a diagram showing the pressure distribution of the air film in the negative pressure slider, and Fig. 4 is a diagram showing the slider. 5 is an exploded perspective view of a magnetic head constructed by applying the present invention, and FIG. 6 is a graph showing the relationship between the flying height of the slider and the circumferential speed of the recording medium. Fig. 7 is a diagram showing the configuration of a conventional magnetic head, Fig. 8 is a perspective view of the slider shown in Fig. 7, and Fig. 9 is a diagram comparing the change over time with that of a conventional magnetic head. It is an explanatory diagram of force. 2... Recording medium, 4... Negative pressure slider, 6... Negative pressure slider holding means, 8... Negative pressure slider driving means, 20... Head arm, 22... Piezoelectric element, 26 ...Spring arm, 28...Gimbal.

Claims (1)

[Claims] 1. A method for driving a magnetic head in a direction perpendicular to the surface of a recording medium, which comprises:
) and negative pressure in the direction toward the recording medium (2) act on the negative pressure slider (4) according to the rotational speed of the recording medium (2). The negative pressure slider (4) is held at a first stable position where no pressure is applied, and a restoring force is applied to the negative pressure slider (4) according to the displacement from the first stable position, and the recording medium (2) is When the rotation of the slider (4) starts and the rotational speed reaches a steady rotational speed, the slider (4) is moved to a second stable position where the restoring force is balanced with the force acting on the negative pressure slider (4) due to the positive pressure and negative pressure. A method for driving a magnetic head, comprising displacing the negative pressure slider (4) from the first stable position to the second stable position so that the negative pressure slider (4) is positioned. 2. Positive pressure in the direction away from the recording medium (2) when the recording medium (2) is located near the recording medium (2);
) a negative pressure slider (4) on which a negative pressure acts in accordance with the rotation speed of the recording medium (2), and a first slider (4) on which the negative pressure and negative pressure do not act Negative pressure slider holding means (6) for holding the slider in a stable position so that a restoring force is applied in accordance with the displacement from the stable position.
and when the rotation speed of the recording medium (2) starts to reach a steady rotation speed, the force acting on the negative pressure slider (4) due to the positive pressure and negative pressure and the restoring force. Negative pressure slider driving means (for displacing the negative pressure slider (4) from the first stable position to the second stable position so that the negative pressure slider (4) is located at a balanced second stable position; 8) A magnetic head drive device comprising: 3. The apparatus according to claim 2, wherein the negative pressure slider holding means (6) includes a head arm (20) provided at a predetermined distance from the recording medium surface;
A spring arm (26) made of an elastic body whose one end side is fixed to the head arm (20), and a spring arm (26) provided at the free end side of the spring arm (26), which are connected to each other on a plane approximately parallel to the surface of the recording medium. The negative pressure slider driving means (8) includes a gimbal (28) that holds the negative pressure slider (4) rotatably within a minute angle range about two orthogonal axes, and the negative pressure slider driving means (8) 1. A magnetic head driving device comprising: a piezoelectric element (22) fixed to the spring arm (22) and abutting the spring arm (26).