JP2002163870A - Magnetic disc device and head supporting mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an actuator for setting a position possible to form with low driving pressure and without producing vertical vibration accompanied with the movement of a head supporting component and dust and using a complicated assembly process and improve precision for setting a head position of a revolving disc-typed information storing device and, and highten recording density. SOLUTION: A second actuator 100 that has two polarizing areas separated in a non-polarizing area and plate type structure laminating piezoelectric plates in a thickness direction of a polarizing direction and an electric field direction that is impressed is fixed like bridging a surface of a suspension 200 and a surface of a suspension supporting component 230 supporting the suspension and it is coated with a resin coating 101.

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 and a head support mechanism for the magnetic disk drive, and more particularly, to a head for writing and reading information at a predetermined position on a magnetic disk where information is stored. The present invention relates to coating of an actuator for high-precision positioning.

[0002]

2. Description of the Related Art Heretofore, a voice coil motor has been used as an actuator for moving a magnetic head to a desired position on a disk. However, in this method, there is a limit in improving the positioning accuracy. Therefore, as a method for performing the positioning operation with higher accuracy, a configuration in which a second actuator for finely adjusting the position of the magnetic head is arranged between the voice coil motor and the magnetic head has been proposed.

For example, the structure of a second actuator described in Japanese Patent Application Laid-Open No. 12-113615 has a magnetic head for writing and reading information, a magnetic disk for storing information, and an elastic disk for supporting the head. A member, a fixing member supporting the elastic member, a first actuator for coarse movement for moving the magnetic head to a predetermined position on a magnetic disk, and a portion between the first actuator and the magnetic head. A second actuator for fine movement arranged at a position where the second actuator has electrodes on the upper surface and the lower surface and has one or two or more polarized regions inside, A plate-like structure composed of a plurality of piezoelectric flat plates, wherein the upper surface or the lower surface of the fixed member and the elastic member is the second plate-like structure. In which were arranged so as to bridge with an upper surface or lower surface of the actuator.

Further, the second actuator is a plate-like structure composed of one or a plurality of laminated piezoelectric flat plates made of a material having piezoelectricity and having electrodes on upper and lower surfaces, The electrodes on at least one of the electrodes on the upper surface and the lower surface are separated into two or more, and the piezoelectric flat plate is separated by a non-polarized region and a part of the non-polarized region. The piezoelectric plate has two or more polarization regions polarized in the thickness direction of the piezoelectric plate inside, and the two or more polarization regions in the piezoelectric plate are on the upper surface and the lower surface of the piezoelectric plate. By applying an electric field in the thickness direction of the piezoelectric flat plate using the electrodes, the piezoelectric flat plate is displaced in the in-plane direction of the piezoelectric flat plate.

[0005]

The second actuator in the above-mentioned prior art is fragile because it is made of a ceramic such as PZT, which is a piezoelectric element, and has a problem in mechanical strength. In addition, this actuator is metallized with Au or the like to attach electrodes, and when a voltage is applied to expand and contract the element, fine particles of PZT and Au are generated. Then, there is a problem that the particles adhere to a magnetic head or a disk or contaminate the inside of the apparatus, which causes a reduction in reliability in writing and reading of information.

[0006]

As a result of an experimental study conducted by the present inventors to solve the above problems, it has been found that the problems can be solved by the following means. That is, in a magnetic disk drive having a second actuator composed of a piezoelectric element, a liquid adhesive is applied to the surface of the second actuator, cured and resin-coated, whereby the element expands and contracts when a voltage is applied. At this time, they have found that fine particles of PZT or metallized Au as a material of the actuator can be prevented from generating dust.

Hereinafter, the present invention will be described in detail. The liquid adhesive used for the resin coating is preferably a low-viscosity resin having a viscosity before curing of 1000 mPas or less in order to uniformly apply a film thickness of 10 μm or less by means such as a dispenser or an ink jet. The resin for application may be a photo-curing (UV, visible light) type, but in the case of thermal curing, it must be a type that cures at a temperature lower than the heat resistance temperature of the piezoelectric element.
In the case of a type that cures at a temperature lower than the heat resistance temperature of the piezoelectric element, a combination of heat and light curing is also possible.

Further, when volatile organic molecules are generated as outgas from the cured resin, it adheres to a magnetic head or a disk or contaminates the inside of the apparatus, and the reliability of writing and reading of information is reduced. The adhesive must be a resin that hardly outgases after curing because it causes deterioration of the properties. Further, the cured resin is flexible, has a low elastic modulus, a high elongation rate, and has a high adhesive strength to the metallized Au and does not cause cracks or the like when the piezoelectric element to which a voltage is applied expands and contracts. It must be a low hardness adhesive.

As a result of investigations by the present inventors on resins satisfying such characteristics, it has been found that a low-viscosity epoxy resin-based adhesive is most suitable. Low viscosity epoxy resin adhesive
Epoxy oligomer having a content of less than 20% and a content of 80%
It comprises the above-mentioned epoxy monomer and contains at least a polymerization initiator, a catalyst and an additive which react by heat or light. The polymerization initiator and the catalyst which react by heat or light may be any of an amine type, an acid anhydride type and a cationic type. Additives can be added in a range that does not adversely affect the adhesion and other properties, and a surfactant for improving the wettability of the adhered surface and a filler for improving the physical properties of the cured product. And so on.

[0010] As such a low-viscosity epoxy resin-based adhesive, for example, World Rock XOC- manufactured by Kyoritsu Chemical Industry Co., Ltd.
11CKF-3 and XOC-11CKF-3H. However, the present invention is not limited thereto, and may be appropriately adjusted from an epoxy oligomer having a content of less than 20% and an epoxy monomer having a content of 80% or more, and a polymerization initiator, a catalyst, and an additive which react with heat or light. Is also good.

On the other hand, adhesives other than low-viscosity epoxy resin adhesives are not suitable as the resin of the present invention. For example,
Since a general low-viscosity coating agent contains a solvent or is an acrylic resin, a large amount of outgas is generated from the cured resin, which is not preferable. Also, in general,
Epoxy-based resins have a high content of epoxy oligomers, have high viscosities, and are difficult to apply uniformly with a film thickness of 10 micrometers or less. In addition, since the cured resin has no flexibility and is hard, cracks and the like occur when the voltage is applied to expand and contract the piezoelectric element, which is not preferable because it causes dust.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described.
This will be described with reference to the drawings. FIG. 1 is a top view showing the structure of a magnetic disk drive according to an embodiment of the present invention. In this embodiment, a magnetic recording disk 310 in which information having a magnetic film formed on the surface is stored, and a spindle motor 300 for rotating the magnetic recording disk 310 are provided. Further, a magnetic head (not shown) comprising an electromagnetic transducer for reading and writing information from and on the magnetic recording disk 310 is provided, and a slider (not shown) for floating at a predetermined interval on the magnetic disk is provided. It has.

The slider is provided on a gimbal 210 for passively correcting the attitude of the slider relative to the magnetic disk. The gimbal 210 is connected to one end of a suspension 200 that is an elastic member that elastically supports the magnetic head and the slider. The other end of the suspension 200 is connected to a suspension support member 230 that is a fixed member. The suspension support member 230 is provided with a first actuator for moving the magnetic head to a predetermined position on the magnetic disk and roughly positioning the magnetic head.

The first actuator includes a voice coil motor 250, a magnet 251 constituting the voice coil motor, a coil 252, and a suspension support member rotating shaft serving as a center of rotation when positioning the magnetic head by the voice coil motor. 241 and a bearing 240. Also, between the voice coil motor and the magnetic head,
A second actuator 100 for fine movement is provided for high-precision positioning.
1. Coat the surface.

FIG. 2A is a top view showing the entire magnetic head supporting mechanism from the suspension supporting member 230 to the magnetic head according to the embodiment of the present invention in more detail. FIG.
FIG. 2B is a cross-sectional view illustrating a cross section A of the entire magnetic head support mechanism illustrated in FIG. Second actuator 10
Reference numeral 0 denotes a plate-like structure in which piezoelectric flat plates described later are stacked. In this embodiment, the suspension support member 230 and the upper surface of the suspension 200 are arranged so as to bridge each other by using the lower surface of the second actuator 100. The lower surface of the second actuator 100 and the upper surface of the suspension 200 are fixed with an adhesive layer 501.
Similarly, the lower surface of the second actuator 100 and the upper surface of the suspension support member 230 are fixed by an adhesive layer 502.

In the present embodiment, the above-mentioned bonding uses an epoxy-based adhesive. Here, the side of the suspension 200 to which the slider 220 is fixed is defined as the lower surface, and the opposite side is defined as the upper surface. On the lower surface of the second actuator 100, a connection electrode 11 for supplying power to the second actuator is provided.
1 and 112 are formed, and are electrically connected to lead electrodes 261 and 262 formed on the upper surface of the suspension support member 230 by using solder. The connection by the solder also contributes to the mechanical connection between the second actuator and the suspension holding arm.

Further, the surface of the second actuator 100 is coated with a coating resin 101. As the coating resin, a low-viscosity epoxy resin-based adhesive is evenly applied to a thickness of 10 μm or less by a method such as a dispenser or ink jet, and is heated by light irradiation (UV, visible light) or an oven furnace or a hot plate. To form and harden. In addition, a combination of heat and light curing is also possible.

FIG. 3A is a top view showing the detailed structure of the second actuator 100 used in the present embodiment.
FIG. 3B is a cross-sectional view illustrating a cross section B of the second actuator illustrated in FIG. The second actuator of this embodiment is a piezoelectric flat plate 105 having a plate-like structure made of a material having piezoelectricity. Piezoelectric flat plate 105
Has two electrodes 118a and 118b on the upper surface and two electrodes 118c and 118d on the lower surface. Here, in the thickness direction of the piezoelectric flat plate, the left side in FIG. 3B is the upper surface side, and the right side is the lower surface side. The piezoelectric flat plate 105 has the electrode 1
Region 60 polarized in the region between 18a and 118c
1 and a region 602 polarized in a region sandwiched between the electrodes 118b and 118d. That is, two polarization regions are provided in one piezoelectric flat plate. As described above, the second actuator according to the present embodiment is a plate-shaped structure including the piezoelectric flat plate 105 having electrodes on the upper surface and the lower surface and having two polarization regions therein.

Next, the operation of the second actuator in this embodiment will be described. FIG. 4 is a cross-sectional view showing an example of the direction of polarization in the piezoelectric flat plate constituting the second actuator and the state of an electric field when the present actuator is driven. The polarization directions of the two polarization regions of the piezoelectric flat plate 105 are in the thickness direction of the piezoelectric flat plate and opposite to each other. An electric field is applied to the piezoelectric flat plate in such a polarized state as shown in FIG. That is, the polarization region 6
01, an electric field is applied so that the direction of polarization is the same as the direction of the electric field, and an electric field is applied to the polarization region 602 such that the direction of polarization is opposite to the direction of the electric field.

FIG. 5A is a top view showing the state of displacement of the second actuator 100 in the plane (positioning direction) when such an electric field is applied. FIG. 5 (b)
FIG. 6C is a sectional view illustrating a displacement of the second actuator illustrated in FIG. 5A in a thickness direction (a direction perpendicular to the upper surface of the actuator). Since the direction of polarization and the direction of the electric field are the same, the polarization region 601 is displaced so as to contract in the in-plane direction and expand in the thickness direction. On the other hand, the polarization region 602 is displaced so as to extend in the in-plane direction and contract in the thickness direction since the polarization direction and the electric field direction are opposite.

Therefore, by applying the above-described electric field to the second actuator, the second actuator 1
The suspension 200 fixed to 00 can be displaced in-plane (in the positioning direction) with respect to the suspension support member 230. By changing the intensity and direction of the applied electric field, the magnetic head fixed to the tip of the suspension 200 can be finely moved in the positioning direction with high accuracy. At this time, as shown in FIG. 5B, the second actuator 100 is also displaced in the thickness direction of the actuator.

In the magnetic disk drive of this embodiment, it is only necessary to fix the second actuator between the suspension and the suspension support member, so that a magnetic disk drive with high productivity can be obtained, and the reliability is high. Instead, a magnetic disk device in which reading and writing of the magnetic head are stable can be achieved.

In this embodiment, since the thickness of one piezoelectric flat plate can be reduced by laminating the piezoelectric flat plates, the strength of the electric field applied to the piezoelectric flat plate (applied to the second actuator) can be reduced. Voltage / thickness of the piezoelectric flat plate) can be increased. Since the displacement of the second actuator is proportional to the strength of the electric field, a large displacement can be obtained with a low voltage. Furthermore, since the second actuator is coated with a resin, it is possible to prevent fine particles of PZT or metallized Au, which is a material of the actuator, from generating dust when the element expands and contracts when a voltage is applied. When the dust generation was actually measured by a particle counter, no particles larger than 1 micrometer were detected in the apparatus, and no information writing / reading error occurred.

Further, the cured film of the resin coated by the method described in this embodiment is a uniform film having a thickness of 5 μm or less, and the cured film has an elastic modulus of 700 or less.
MPa, elongation percentage is 50%, Shore D hardness is 70, and it is flexible. Therefore, by applying a voltage of 5 V, the piezoelectric element
Cracks did not occur even after stretching 100 million times.

On the other hand, when the cured resin was analyzed by GC-MS, outgas (volatile organic molecules) was detected at 0.005 micrograms per milligram of the resin. / No read error occurred. Note that, in addition to the above-described embodiments, many methods for applying an electric field to two polarization regions in the piezoelectric flat plate can be considered. When different electric fields are applied to the two polarization regions, the same in-plane displacement can be generated. Further, although the number of polarization regions in the piezoelectric flat plate is two, three or more polarization regions may be provided.

In the above embodiment, the second actuator is arranged so as to bridge the upper surfaces of the suspension and the suspension support member. However, the second actuator may be arranged so as to bridge the lower surfaces. In addition, one element, which is a piezoelectric flat plate, is fixed as the second actuator so as to bridge the upper surfaces of the suspension and the suspension support member. You may fix so that lower surfaces may be bridge | crosslinked. In this case, one element is fixed so as to bridge the upper surfaces of the suspension and the suspension support member, and the other element is fixed so as to bridge the lower surfaces of the suspension and the suspension support member.

Further, in the above embodiment, the second actuator is disposed between the suspension and the suspension support member. However, the second actuator may be disposed within the suspension support member or may be disposed within the suspension. Good. Further, all of the above embodiments relate to a magnetic disk device, but may be used for a magnetic disk array device in which a plurality of magnetic disk devices are arranged, or a storage device using a rotary recording medium other than a magnetic disk, for example, Of course, it may be used for an optical disk device, a magneto-optical recording device, or the like.

Next, another embodiment of the present invention will be described with reference to the drawings. The resin coating of the second actuator described in the first embodiment was applied to the Journal of the Institute of Electrical Engineers of Japan 1
This is applied to a head support mechanism (FIG. 6) as described in FIG. 3 on page 691 of Vol. 20, No. 11, November 2000.
That is, two elements 100a, 100b arranged horizontally
And a φ-type hinge 700 for connecting a suspension 200 and a suspension support member 210 to a magnetic head supporting mechanism (FIG. 6), a magnetic disk device using the above magnetic head supporting mechanism, and a rotary recording medium other than a magnetic disk. The same effect as in the first embodiment described above can be obtained by using the same storage device.

In this case, the resin coating is applied after the two elements 100a and 100b are electrically and mechanically connected to the suspension 200 and the suspension support member 210. At this time, the φ type hinge 70
There is a small possibility that the gap 800 between 0 and the two elements 100a and 100b will be filled with resin. However, even if the gap is filled with resin, the second actuator 100, that is, the displacement of the head that can be generated by the two elements 100a and 100b is not affected.

As a result of the experiment, the displacement when the gap was filled with the resin used in the first embodiment (the elastic modulus after curing was 700 MPa) was the same as the displacement when the gap 800 was not filled with the resin. It was 99.9% or more.

Next, a comparative example for comparison with the above-described embodiment will be described. As Comparative Example 1, JP-A-12-113
According to the method described in Japanese Patent Application Laid-Open No. 615, a magnetic disk drive manufactured without performing resin coating detects 131 dust particles of 1 μm or more in the drive by measuring with a particle counter, and detects information write / read errors. There has occurred.

As Comparative Example 2, a resin coating 101 having a general viscosity of 10 was prepared by the method described in this example.
000mPas epoxy adhesive,
The film had a high viscosity and did not become a uniform film having a thickness of 10 μm or less after coating and curing. The cured film had an elastic modulus of 2000 MPa, an elongation of 3%, a Shore D hardness of 90, and was hard. When a 5 V voltage was applied to expand and contract the piezoelectric element 10,000 times, cracks occurred.

As Comparative Example 3, a resin coating was applied to a resin having a general viscosity of 8000 m by the method described in this example.
When using Pas acrylic adhesive, volatile organic molecules were generated as outgas from the cured resin, and G
When analyzed by C-MS, 1.1 micrograms per milligram of resin were detected, and an information write / read error occurred.

[0034]

According to the present invention, the actuator can be driven at a low voltage. Since there is no displacement in the vertical direction with respect to the upper surface of the actuator at the time of driving and no dust is generated, it is possible to provide a magnetic disk device with high write / read reliability of the magnetic head and high productivity. Thereby, it is possible to improve the recording density of the rotating disk type information storage device.

[Brief description of the drawings]

FIG. 1 is a top view showing the structure of a magnetic disk drive according to an embodiment of the present invention.

FIG. 2 is a top view and a cross-sectional view showing the entire magnetic head support mechanism used in the magnetic disk drive of the present invention.

3A and 3B are a top view and a cross-sectional view illustrating a structure of a second actuator.

FIG. 4 is a sectional view showing a polarization region of a second actuator.

5A and 5B are a top view and a cross-sectional view showing displacement of a second actuator.

FIG. 6 is a perspective view showing the entire magnetic head support mechanism according to another embodiment.

[Explanation of symbols]

100, 100a, 100b ... second actuator,
101: coating resin, 111, 112: connecting electrodes, 118a, 118b, 118c, 118d: electrodes
105: piezoelectric flat plate, 200: suspension, 210
... Gimbal, 220 ... Slider, 230 ... Suspension support member, 240 ... Bearing, 241 ... Suspension support member rotating shaft, 250 ... Voice coil motor, 251
... permanent magnet, 252 ... coil, 300 ... spindle motor, 261, 262 ... lead-out electrode, 310 ... magnetic disk, 501, 502 ... adhesive layer, 601, 602 ... polarization region, 700 ... φ hinge, 800 ... gap

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shigeo Nakamura 2880 Kozu, Kodawara-shi, Kanagawa Prefecture Within the Storage Systems Division, Hitachi, Ltd. (72) Inventor Osamu Narusawa 2880 Kozu, Kozu, Odawara-shi, Kanagawa Storage, Hitachi, Ltd. F term in the system division (reference) 5D068 AA00 BB01 CC11 EE15 EE19 GG03 5D096 NN03 NN07

Claims (16)

[Claims] A magnetic head for writing and reading information, a magnetic disk for storing information, an elastic member for supporting the magnetic head, a fixed member for supporting the elastic member, and a magnetic head. A first actuator for moving to a predetermined position on the magnetic disk; and a second actuator disposed between the first actuator and the magnetic head, wherein the second actuator is A magnetic disk drive characterized by being coated with a resin. 2. The magnetic disk drive according to claim 1, wherein the viscosity of the resin before curing is a low-viscosity resin of 1000 mPas or less. 3. The magnetic disk drive according to claim 1, wherein said resin is an epoxy resin. 4. A magnetic disk drive according to claim 1, wherein said resin comprises an epoxy oligomer having a content of less than 20% and an epoxy monomer having a content of 80% or more, and is a polymerization initiator or a catalyst which reacts at least by heat or light. And a additive. 5. The magnetic disk drive according to claim 1, wherein the elastic modulus of the resin after curing is 1000 MPa or less. 6. The magnetic disk drive according to claim 1, wherein the Shore D hardness of the resin after curing is 80 or less. 7. The magnetic disk drive according to claim 1, wherein an elongation percentage after curing of the resin is 30% or more. 8. A magnetic disk drive according to claim 1, wherein said resin is applied by means such as a dispenser or an ink jet. 9. A magnetic head for writing and reading information, an elastic member for supporting the magnetic head, a fixed member for supporting the elastic member, and the magnetic head between the elastic member and the fixed member. A head support mechanism provided with an actuator for positioning, wherein the actuator is coated with a resin. 10. The head support mechanism according to claim 9, wherein the viscosity of the resin before curing is a low-viscosity resin of 1000 mPas or less. 11. The head support mechanism according to claim 9, wherein said resin is an epoxy resin. 12. A head support mechanism according to claim 9, wherein said resin comprises an epoxy oligomer having a content of less than 20% and an epoxy monomer having a content of not less than 80%, and a polymerization initiator and a catalyst which react at least by heat or light. And a head support mechanism comprising an additive. 13. The head support mechanism according to claim 9, wherein the elastic modulus of the resin after curing is 1000 MPa or less. 14. The head support mechanism according to claim 9, wherein the Shore D hardness of the resin after curing is 80 or less. 15. The head support mechanism according to claim 9, wherein an elongation percentage after curing of the resin is 30% or more. 16. A head supporting mechanism according to claim 9, wherein said resin is applied by means of a dispenser, ink jet or the like.