JP2007149330A - Head gimbal assembly and disk drive unit including the head gimbal assembly - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance vibration-proof capacity by preventing conflict of a micro-actuator. <P>SOLUTION: The constitution includes a slider 302, the micro-actuator 304 having two thin film piezoelectric pieces, and a suspension mounting the slider 302 and the micro-actuator 304. The suspension includes a flexure 306 including an actuator mounting part 412 in which a slot 415 corresponding to a concave groove 341 of the micro-actuator 304 is formed and a slider mounting part 411 supporting partially the slider 302, and a load beam 315 including a first dimple 318 supporting the flexure 306 at a position opposing to a center region of the slider 302 and a second dimple 303 which is pierced through the slot 415 of the flexure 306 and the concave groove 341 of the micro-actuator, extended to a moving end of the slider 302, and forms a gap between the slider 302 and the second dimple. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a disk drive unit, and more particularly to a head gimbal assembly (HGA) for protecting a microactuator mounted on the disk drive unit.

A disk drive unit is generally widely used as an information recording apparatus. The disk drive unit executes writing or reading of data on a magnetic disk or the like by arranging a magnetic recording / reproducing head on a rotating magnetic medium. As shown in FIGS. 1 a and 1 b, the conventional disk drive includes a drive arm 105 and a magnetic disk 106. This drive arm 105 is applied to drive the head gimbal assembly 104. A slider 202 is attached to the head gimbal assembly 104. The magnetic disk 106 is mounted on a spindle motor 103 and is driven to rotate by the spindle motor 103. A voice coil motor (VCM) 102 controls the operation of the driving arm 104 and further drives the head gimbal assembly 104 to move a slider 202 having a recording / reproducing sensor to a track on the surface of the magnetic disk 106. Thus, information can be recorded / reproduced on / from the magnetic disk 106.
However, since the inherent error of the voice coil motor 102 exists in the displacement of the slider 202, the slider 202 cannot perform accurate position adjustment.

  In order to solve the above problem, the position of the slider is adjusted using a piezoelectric microactuator. That is, the tolerance of the voice coil motor and the manufacturing error of the internal module of the drive arm can be corrected by using the piezoelectric microactuator and adjusting the position of the slider 202 with a smaller width. Accordingly, the present invention can be applied to a recording width of a smaller track, and the TPI value (tracks per inch) of the disk drive unit can be increased by about 50% (at the same time, the surface recording density can be increased. ).

  2A and 2B, the conventional head gimbal assembly 200 has a suspension 208, a recording / reproducing sensor (not shown), a slider 202 attached to the tip of the suspension 208, and the suspension 208. And a microactuator 204 for finely adjusting the position of the slider 202. The suspension 208 includes a substrate 219 assembled together, a flexure 206, a load beam 215, and a hinge 213. 2A to 2C, the flexure 206 includes a flexure main body 261, a slider support plate 212, and a conductor support plate 213 for supporting the flexure main body 261. Further, the flexure 206 includes a slider mounting portion 211 that partially fixes the slider 202, and the moving end 272 of the slider 202 is exposed to the microactuator 204. The load beam 215 has dimples 218 and supports the flexure 206 at a position facing the center area of the slider 202. However, when an impact or vibration is applied to the head gimbal assembly 200 or the disk drive unit including the head gimbal assembly 200, the slider 202 rotates in the direction 220 in the direction 220 around the dimple 218 toward the microactuator 204. For this reason, the moving end 272 of the slider 202 may collide with the microactuator 204, and the microactuator 204 may be damaged by the collision.

  Also, as shown in FIG. 2b, the microactuator 204 is electrically connected to the flexure 206 via a wire-bonding method. However, line connection bumps are likely to occur according to the line connection method. This line connection bump adversely affects the electrical connection between the microactuator 204 and the flexure 206. In addition, such a line connection method is difficult to operate and expensive. Further, since there is no reference structure for mounting, it is very difficult to accurately mount the microactuator to the suspension of the head gimbal assembly.

  In view of the above problems, it has been desired to provide a head gimbal assembly and a disk drive unit that have improved the problems of the prior art.

SUMMARY OF THE INVENTION An object of the present invention is to provide a head gimbal assembly and a disk drive unit capable of preventing the collision between a slider and a microactuator mounted in the head gimbal assembly and improving the vibration isolation performance.
Another object of the present invention is to provide a head gimbal assembly and a disk drive unit that can reduce the manufacturing cost of the head gimbal assembly and further increase the reliability of the electrical connection of the head gimbal assembly.
Furthermore, another object of the present invention is to provide a head gimbal assembly and a disk drive unit that can improve the assembly accuracy of the head gimbal assembly.

  In order to achieve the above object, a head gimbal assembly according to the present invention includes a slider, a microactuator having two thin film piezoelectric pieces, and a suspension on which the slider and the microactuator are mounted. Among them, the microactuator has a concave groove formed between two thin film piezoelectric pieces, the suspension includes a flexure including an actuator mounting portion and a slider mounting portion, and a load beam including a first dimple and a second dimple. And a slot corresponding to the concave groove of the microactuator is formed in the actuator mounting portion, the slider mounting portion partially supports the slider, and the first dimple is located at a position facing the central area of the slider. The second dimple is configured to pass through the slot of the flexure and the concave groove of the microactuator and extend to the moving end of the slider to form a gap between the slider.

  In the embodiment of the present invention, the width of the gap formed between the slider and the second dimple is preferably 20 to 60 μm. The second dimple preferably includes a soft top for absorbing shock or vibration.

  Furthermore, in another embodiment of the present invention, an actuator mounting hole is formed at a position corresponding to the second dimple of the concave groove of the microactuator, and a flexure mounting hole is formed at a position corresponding to the second dimple of the flexure slot. When the microactuator, the flexure, and the load beam are assembled together, it is preferable that the second dimple is inserted through the flexure mounting hole and the actuator mounting hole in order to ensure high assembly accuracy.

  In the embodiment of the present invention, the thin film piezoelectric piece can be configured to be attached to the flexure via an anisotropic conductive film. Here, each thin film piezoelectric piece includes a conductive layer, an insulating layer, and a piezoelectric layer sandwiched between the conductive layer and the insulating layer, a microactuator is attached to the flexure, and the conductive layer faces the flexure. It is preferable.

  In order to achieve the above object, a disk drive unit of the present invention includes a head gimbal assembly, a drive arm connected to the head gimbal assembly, a magnetic disk, and a spindle motor that rotates the magnetic disk. . Among them, the head gimbal assembly includes a slider, a microactuator having two thin film piezoelectric pieces, and one concave groove is formed by the two thin film piezoelectric pieces, and a suspension on which the slider and the microactuator are mounted. The suspension includes a flexure including an actuator mounting portion and a slider mounting portion, and a load beam including a first dimple and a second dimple, and a slot corresponding to the concave groove of the microactuator is formed in the actuator mounting portion. The slider mounting portion partially supports the slider, the first dimple supports the flexure at a position facing the center area of the slider, the second dimple passes through the slot of the flexure and the concave groove of the microactuator, and Extends to the moving end, and with the slider It is configured to form a gap.

  In the present invention, the second dimple formed on the load beam is closer to the slider than the microactuator, and can be used as a limiting device for preventing operations such as rotational movement of the slider. For this reason, it is possible to prevent the slider and the microactuator from colliding with each other, and thus to protect the microactuator. Further, since the added dimple can limit the inappropriate operation of the slider, the vibration isolation performance of the head gimbal assembly and the disk drive unit can be improved. Furthermore, the head gimbal assembly of the present invention uses an anisotropic conductive film instead of a line connection method to physically connect and electrically connect the microactuator to the flexure to realize a good connection. Bumps due to the connection method can be prevented. Further, a connection method using an anisotropic conductive film is inexpensive and easy to operate. In addition, since the thin film piezoelectric piece of the microactuator faces the insulating layer of the slider, the microactuator is protected from damage due to the protection of the piezoelectric layer even when impact or vibration occurs from the slider. The

Hereinafter, specific embodiments of the present invention will be described with reference to the drawings. In the attached drawings, the same or corresponding parts are denoted by the same reference numerals.
As described above, the present invention provides a head gimbal assembly having a microactuator protection structure. This protective structure can protect the microactuator when an impact or vibration occurs in the disk drive unit including the head gimbal assembly. For example, damage to the thin film piezoelectric microactuator can be avoided.
Specifically, dimples are formed on the load beam of the suspension of the head gimbal assembly in the present invention. The dimple passes through the flexure of the suspension and the microactuator and extends to the moving end of the slider of the head gimbal assembly to form a gap between the slider and the second dimple.
In the present invention, the flexure further includes a slider mounting portion that partially supports the slider, and the moving end of the slider is exposed to the microactuator. The load beam has a first dimple that supports the flexure at a position facing the central area of the slider.
Conventionally, when an impact or vibration occurs in the head gimbal assembly or the disk drive unit including the head gimbal assembly, the slider rotates around the first dimple, so that the moving end of the slider collides with the microactuator. There was a risk of damage.
In the present invention, the second dimple is further brought closer to the slider than the microactuator, so that an operation such as a rotary motion of the slider can be prevented. Therefore, it is possible to protect the microactuator by preventing the slider from colliding with the microactuator. Further, since the added second dimple can limit an inappropriate operation of the slider, the vibration isolation performance of the head gimbal assembly and the disk drive unit can be enhanced.

Hereinafter, embodiments of the head gimbal assembly according to the present invention will be described.
3A and 4A, in the embodiment of the present invention, the head gimbal assembly 300 includes a slider 302, a microactuator 304, and a suspension 308 on which the slider 302 and the microactuator 304 are mounted. .
The slider 302 includes a recording / reproducing sensor (not shown) provided during manufacture and a plurality of connection pads 352 formed on the base end edge of the slider 302.
The suspension 308 includes a substrate 319, a hinge 313, a flexure 306, and a load beam 315 assembled together.
The flexure 306 includes a plurality of conductive wires 309, one end of each of the conductive wires 309 is electrically connected to the microactuator 304, and the other end is electrically connected to the plurality of electric pads 311.
In this embodiment, these electric pads 311 are connected to one control system (not shown), and a control signal generated from the control system is input to the microactuator 304 via these electric pads 311. The microactuator 304 is controlled.
These conductors 309 are also electrically connected to the slider 302, allowing the slider 302 to be controlled by the control system through the electrical pad 311.

As shown in FIG. 4 a, the flexure 306 includes a flexure body 361, a slider support plate 362, and a conductor support plate 363. The flexure 306 further includes an actuator mounting portion 412 and a slider mounting portion 411 that is located at one end of the flexure 306 and partially supports the slider 302, and a slot 415 is formed in an intermediate area of the actuator mounting portion 412. Has been.
Further, a plurality of electric pads 408 are formed at a location near the actuator mounting portion 412 of the flexure 306. At the same time, the flexure 306 has an electrical pad 471 corresponding to the electrical connection pad 352 of the slider 302.
In this embodiment, the slider support plate 362 and the conductor support plate 363 are attached to the back of the flexure body 361 and are used to increase the hardness of the flexure body 361 and the flexure 306.
As another embodiment of the present invention, the slider support plate 362 and the conductor support plate 363 may be formed through local etching of the flexure 306 during the flexure 306 manufacturing process.

As shown in FIG. 4a, the microactuator 304 includes two piezoelectric pieces 304a and 304b, each of which is sandwiched between the conductive layer 402, the insulating layer 404, and the conductive layer 402 and the insulating layer 404, respectively. The piezoelectric layer 403 has a three-layer structure.
Further, the two piezoelectric pieces 304a and 304b are interconnected at one end, and therefore, a concave groove 341 is formed between the two, and an electric pad 408 corresponding to the electric pad 408 is formed at the same end of the piezoelectric pieces 304a and 304b. A pad 406 is formed.
In the present embodiment, the concave groove 341 is formed corresponding to the slot 415 of the flexure 306.

As shown in FIG. 4a, the load beam 315 is provided with two restriction devices 317 extending from both sides of one end of the main body.
This limiting device 317 is used to limit excessive bending of the flexure 306 relative to the load beam 315.
As shown in FIGS. 3 b, 4 a and 4 b, the load beam 315 has a first dimple 318 and supports the flexure 306 at a position corresponding to the central area of the slider 302. Thus, when the slider 302 floats on the surface of the magnetic disk (not shown), a load is applied to the center area of the slider 302 via the first dimple 318.
Further, the load beam 315 includes one or two second dimples 303 near the first dimple 318. When the head gimbal assembly 300 is assembled, the second dimple 303 passes through the slot 415 of the flexure 306 and the concave groove 341 of the microactuator 304, and then extends to the moving end 321 of the slider so as to be in contact with the slider. A gap 500 is formed.
The gap 500 can avoid the influence from the second dimple 303 and ensure the flying performance of the slider 302 on the surface of the magnetic disk (not shown). The gap 500 serves as a space cushion. When the slider 302 rotates toward the microactuator 304 due to external impact or vibration, the gap 500 causes the slider 302 to collide with the second dimple 303. Can be buffered. In the present embodiment, the width of the gap 500 is 20 to 60 μm.

  In the present embodiment, the second dimple 303 has a configuration with a soft top (not shown) for absorbing shock and vibration. The second dimple 303 has an appropriate shape that can be inserted into the slot 415 of the flexure 306 and the concave groove 341 of the microactuator 304, such as a dome shape or a nail shape, and is a polymer, for example. A good cushioning performance can be obtained by forming from any suitable soft material.

Also, as shown in FIGS. 4a, 4c and 4d, the microactuator 304 in this embodiment is attached to the flexure 306 according to the following steps. That is, first, an anisotropic conductive film (ACF) sheet 502 is disposed on the flexure 306 so as to cover the electrical pad 408 of the flexure 306.
Next, the microactuator 304 is placed on the flexure 306, and the electrical pad 406 of the microactuator 304 and the electrical pad 408 of the flexure 306 are aligned, and at the same time, the groove 341 of the microactuator 304 and the slot 415 of the flexure 306 are aligned. Thereby, the sheet 502 of the anisotropic conductive film is sandwiched between the microactuator 304 and the flexure 306, and physical connection between the microactuator 304 and the flexure 306 is realized.
Further, the electrical pad 408 of the flexure 306 is electrically connected to the electrical pad 406 of the microactuator 304 via the anisotropic conductive film sheet 502, and electrical connection between the microactuator 304 and the flexure 306 is realized.
Unlike the line connection method of the prior art, the head gimbal assembly in the present invention uses an anisotropic conductive film to physically and electrically connect the microactuator and the flexure to achieve a good connection. It is possible to prevent the occurrence of bumps. In addition, a connection method using an anisotropic conductive film is inexpensive and easy to operate.

Specifically, as shown in FIGS. 4 c and 4 d, each piezoelectric piece 304 a and 304 b includes a conductive layer 402 that faces the flexure 306 and is electrically connected to the flexure 306. This allows the insulating layer 404 of the piezoelectric piece to face the slider 302 (see FIG. 4a), and avoids damage to the piezoelectric layer 403 even when the second dimple 303 is not formed on the head gimbal assembly 300. Can do.
That is, when an impact or vibration occurs, the slider rotates toward the microactuator 304 and only collides with the surface (insulating layer 404) of the piezoelectric piece 304a or 304b, and the piezoelectric layer 403 is not damaged. With such a configuration, the collision with the microactuator 304 hardly affects the physical and electrical characteristics of the microactuator 304.

As shown in FIGS. 3a, 3b, and 4a, in the present embodiment, the slider 302 is partially formed on the slider mounting portion 411 of the flexure 306 using an adhesive or epoxy-resin glue. Mounted. Here, the electrical pads 471 of the flexure 306 and the connection pads 352 of the slider 302 are connected via a plurality of metal balls (gold ball bonding or solder ball bonding; GBB or SBB, not shown). There is an electrical connection, and thus the slider 302 is connected to the control system through a conductor 309.
According to this embodiment, as shown in FIG. 3a, the load beam 315, the flexure 306, the substrate 319, and the hinge 313 are assembled by a conventional method such as laser welding to form a suspension 308. Thereafter, the slider 302 and the microactuator 304 are attached to the suspension 308 to form the head gimbal assembly 300.

  In the present embodiment, the second dimple 303 is formed at a height higher than the ceiling surface of the microactuator 304 and lower than the bottom surface of the slider 302. Thus, when the slider 302 rotates toward the microactuator 304 due to impact or vibration, the second dimple 303 can prevent the slider 302 from colliding with the microactuator 304 and protect the microactuator 304.

[Other Embodiments]
Hereinafter, a head gimbal assembly 300 ′ according to another embodiment of the present invention will be described with reference to FIGS. 5a and 5b. The head gimbal assembly 300 ′ has almost the same configuration as the head gimbal assembly 300 described above, except that the microactuator and flexure are different.
That is, the head gimbal assembly 300 ′ includes a microactuator 304 ′ composed of two thin film piezoelectric pieces 304′a and 304′b, and each piezoelectric piece forms a semicircular hole (not shown) inside. is doing. As a result, a circular reference hole 503 is formed in an intermediate area of the concave groove 341 of the microactuator 304 ′, and this circular reference hole 503 is engaged with the second dimple 303 on the load beam 315. .
The head gimbal assembly 300 ′ has a flexure body 361 and a flexure 306 ′ composed of a slider support plate 362 and a conductor support plate 363. A circular reference hole 504 is also formed in the slot 415 of the flexure 306 ′, and this reference hole 504 is engaged with the second dimple 303 and the circular reference hole 503.
When assembling the microactuator, flexure, and load beam, the second dimple 303 is inserted through the circular reference holes 503 and 504 in order, so that higher assembly accuracy of the head gimbal assembly 300 ′ can be ensured.

  Of course, the head gimbal assembly according to the present invention is not limited to the structure of the above embodiment, and the present invention can be applied to a head gimbal assembly including any appropriate flexure and load beam. .

Hereinafter, a disk drive unit including the head gimbal assembly described above will be described with reference to FIG.
A disk drive unit 900 according to an embodiment of the present invention includes a case 901, a magnetic disk 906, a spindle motor 903, a flexible printed circuit 907, a voice coil motor 902, a drive arm 905, the head gimbal assembly 300, and the like. It is the structure containing.
The head gimbal assembly 300 has a microactuator protection structure, and this structure improves the vibration isolation performance of the disk drive unit 900. It should be noted that the structure of the disk drive unit and the assembly process of the head gimbal assembly in the embodiment of the present invention are techniques well known to those skilled in the art, and a detailed description thereof will be omitted. Of course, the disk drive unit can also be applied to head gimbal assemblies having other structures suitable for the present invention.

  The present invention has been described above with the best embodiment. However, the present invention is not limited to the above-described embodiment, and various modifications are of course possible.

It is a perspective view of the conventional disk drive unit. FIG. 1b is an enlarged local view of FIG. 1a. It is a perspective view of the head gimbal assembly of the present invention. 2b is an exploded perspective view of a portion of the head gimbal assembly shown in FIG. 2a. FIG. 2b is a cross-sectional view of the head gimbal assembly shown in FIG. 2a. FIG. It is a perspective view of the head gimbal assembly in the embodiment of the present invention. FIG. 3b is a cross-sectional view of the head gimbal assembly shown in FIG. 3a. 3B is an exploded perspective view of the head gimbal assembly shown in FIG. 3A. FIG. 3B is a top view after the slider is removed from the head gimbal assembly shown in FIG. 3A. FIG. It is the figure which showed the connection relation of the microactuator and the flexure of the head gimbal assembly shown in FIG. 3a, and the structure of the thin film piezoelectric piece of the microactuator. FIG. 3c is an exploded view of FIG. 3c. It is a perspective view of the head gimbal assembly in another embodiment of the present invention. FIG. 5b is a top view after the slider is removed from the head gimbal assembly shown in FIG. 5a. 1 is a perspective view of a disk drive unit in an embodiment of the present invention.

Explanation of symbols

200: head gimbal assembly, 202: slider, 204: microactuator, 206: flexure, 208: suspension, 215: load beam, 218: dimple, 261: flexure body, 272: moving end,
300: head gimbal assembly, 302: slider, 303: second dimple, 304: microactuator, 306: flexure, 308: suspension, 309: conductor, 315: load beam, 318: first dimple, 341: concave groove, 361 : Flexure body, 362: slider support plate, 363: conductor support plate,
402: conductive layer, 403: piezoelectric layer, 404: insulating layer, 415: slot,
500: gap, 503, 504: reference hole

Claims (12)

A head gimbal assembly,
A slider,
A microactuator having two thin film piezoelectric pieces and having a groove formed between the two thin film piezoelectric pieces;
A suspension on which the slider and the microactuator are mounted,
The suspension is
An actuator mounting portion in which a slot corresponding to the concave groove of the microactuator is formed, and a flexure including a slider mounting portion that partially supports the slider;
A first dimple that supports the flexure at a position facing a central area of the slider, and extends through the slot of the flexure and a concave groove of the microactuator to the moving end of the slider; and A load beam provided with a second dimple that forms a gap therebetween,
A head gimbal assembly characterized by that. The width of the gap formed between the slider and the second dimple is 20 to 60 μm.
The head gimbal assembly according to claim 1. The second dimple includes a soft top for shock or vibration absorption,
The head gimbal assembly according to claim 1. An actuator mounting hole is formed at a position corresponding to the second dimple of the concave groove of the microactuator, and a flexure mounting hole is formed at a position corresponding to the second dimple of the slot of the flexure,
When assembling the microactuator, the flexure and the load beam together, the second dimple ensures high assembly accuracy by sequentially inserting the flexure mounting hole and the actuator mounting hole.
The head gimbal assembly according to claim 1. The thin film piezoelectric piece is attached to the flexure through an anisotropic conductive film.
The head gimbal assembly according to claim 1. Each thin film piezoelectric piece includes a conductive layer, an insulating layer, and a piezoelectric layer sandwiched between the conductive layer and the insulating layer, and the microactuator is attached to the flexure, and the conductive layer is attached to the flexure. opposite,
The head gimbal assembly according to claim 1. A disk drive unit including a head gimbal assembly, a drive arm connected to the head gimbal assembly, a magnetic disk, and a spindle motor for rotating the magnetic disk;
The head gimbal assembly is
A slider,
A microactuator having two thin film piezoelectric pieces and having a groove formed between the two thin film piezoelectric pieces;
A suspension on which the slider and the microactuator are mounted,
The suspension is
An actuator mounting portion in which a slot corresponding to the concave groove of the microactuator is formed, and a flexure including a slider mounting portion that partially supports the slider;
A first dimple that supports the flexure at a position facing a central area of the slider, and extends through the slot of the flexure and a concave groove of the microactuator to the moving end of the slider; and A load beam provided with a second dimple that forms a gap therebetween,
A disk drive unit characterized by that. The width of the gap formed between the slider and the second dimple is 20 to 60 μm.
The disk drive unit according to claim 7, wherein: The second dimple includes a soft top for shock or vibration absorption,
The disk drive unit according to claim 7, wherein: An actuator mounting hole is formed at a position corresponding to the second dimple of the concave groove of the microactuator, and a flexure mounting hole is formed at a position corresponding to the second dimple of the slot of the flexure,
When assembling the microactuator, the flexure and the load beam together, the second dimple ensures high assembly accuracy by sequentially inserting the flexure mounting hole and the actuator mounting hole.
The disk drive unit according to claim 7, wherein: The thin film piezoelectric piece is attached to the flexure through an anisotropic conductive film.
The disk drive unit according to claim 7, wherein: Each thin film piezoelectric piece includes a conductive layer, an insulating layer, and a piezoelectric layer sandwiched between the conductive layer and the insulating layer, the microactuator is attached to the flexure, and the conductive layer is the flexure. Opposite
The disk drive unit according to claim 7, wherein:

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