JP2009223965A - Actuator, magnetic head assembly, and magnetic disk device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic head assembly for slightly displacing a magnetic head accurately in a plane parallel to the surface of a magnetic disk, exhibiting excellent high-speed follow-up performance, and having almost no restrictions on space of a direction vertical to the surface of the magnetic disk. <P>SOLUTION: The magnetic head assembly includes a pair of piezoelectric elements 30 disposed in both sides of a slider 13 to elongate/shrink in a back and forth direction of the slider, and a hinge 40 disposed on the piezoelectric element 30 and the slider 13. The hinge 40 includes beam members 42 and 43 disposed to support the piezoelectric element 30 at the tip and base end sides, and a column member 41 having a crank part 41b bent into a crank shape, formed to be point-symmetrical with respect to the center of the crank part 41b, and interconnecting the beam members 42 and 43. The slider 13 is bonded to the hinge 40 by the crank part 41b, and the hinge 40 is bonded to a suspension 14b on the upper surface of the beam member 42. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an actuator suitable for controlling a minute displacement of a magnetic head used in a magnetic disk device, a magnetic head assembly using the actuator, and a magnetic disk device.

  In recent years, actuators have been used in many information devices for movement control of small parts at a minute distance. For example, in information equipment equipped with an optical system, an actuator is used for focus correction and tilt angle control. In an ink jet printer or a magnetic disk device, an actuator is used for movement control of the printer head or the magnetic head. In recent years, miniaturization and high performance of these information devices have been promoted, and accordingly, an actuator capable of controlling movement of a minute distance with high accuracy is desired.

  In the case of a magnetic disk device, the recording capacity per magnetic disk has been remarkably increased with the demand for larger capacity. In order to increase the recording capacity without changing the size of the magnetic disk, the number of tracks per unit length (Track Per Inch: TPI) should be increased, that is, the track width should be narrowed and arranged at a high density. Is essential. For this reason, it is necessary to precisely control the position of the magnetic head in the radial direction of the magnetic disk.

  The magnetic head (recording element and reproducing element) is disposed at the tip of a substantially rectangular parallelepiped member called a slider. In a conventional magnetic disk apparatus, a suspension arm that supports a slider is rotated within a predetermined angle range in a direction parallel to the surface of the magnetic disk by an electromagnetic actuator (voice coil motor) to position the magnetic head. However, as the track density increases, it has become difficult to precisely control the positioning of the magnetic head by simply rotating the suspension arm with an electromagnetic actuator.

  For this reason, in order to increase the positioning accuracy in the track width direction, a method has been proposed in which a microactuator is disposed between the slider and the suspension and the slider is driven by the microactuator to position the magnetic head minutely.

  Patent documents 1 and 2 exist as documents considered to be related to the present invention.

  Patent Document 1 describes an actuator that positions in the track direction by disposing a piezoelectric actuator so as to be sandwiched between a slider and a suspension and applying a rotational motion to the slider.

Patent Document 2 describes an actuator that performs positioning by displacing the slider in the track direction by a piezoelectric element disposed on the side of the slider.
JP 2003-284362 A Japanese Patent Laid-Open No. 2004-188587

  However, since the actuator described in Patent Document 1 has a piezoelectric element disposed between the slider and the suspension, the thickness in the direction perpendicular to the surface of the magnetic disk increases. For this reason, there is a possibility that it is necessary to reduce the number of mounted magnetic disk devices in which a plurality of magnetic disks (magnetic recording media) are mounted.

  On the other hand, in the actuator described in Patent Document 2, when the slider is moved in translation, the vibration of the suspension increases due to the movement of the center of gravity of the slider, the control band decreases due to the resonance frequency of the suspension, and the high-speed followability becomes insufficient. There is a fear. Further, in the actuator having the structure described in Patent Document 2, there is a possibility that a sufficient amount of displacement cannot be ensured if a rotational motion is applied to the slider.

  An object of the present invention is to provide an actuator that can accurately displace a target object within a predetermined plane with high accuracy and is excellent in high-speed tracking.

  Another object of the present invention is to provide a magnetic head assembly and a magnetic disk device that are capable of finely displacing a magnetic head in a plane parallel to the surface of the magnetic disk with high precision and excellent in high-speed tracking. That is.

  According to one aspect of the present invention, a pair of piezoelectric elements that are disposed on both sides in the width direction of an object and expand and contract in the front-rear direction of the object by applying a voltage, and the pair of piezoelectric elements in one of the expansion and contraction directions The first beam member fixed to the support member and the pair of piezoelectric elements are held at the other end in the expansion / contraction direction, and the first and second piezoelectric elements are expanded and contracted to extend the first A second beam member that is displaced so as to approach or leave the beam member side; and a columnar member that has a crank-shaped bent portion, connects the first and second beam members, and supports the object. An actuator characterized by comprising:

  According to the actuator of the above aspect, when a voltage is applied to the piezoelectric element to displace the second beam member so as to approach or leave the first beam member side, the column member is deformed within a predetermined plane. Since this column member has a crank-like bent portion and is formed in point symmetry with respect to the center of the bent portion, a force that rotates around the center acts on the bent portion. Thereby, the displacement of the piezoelectric element is converted into the displacement in the rotational direction by the bent portion of the column member. In the actuator of this aspect, since the center of gravity of the object is joined so as to coincide with the center of the bent part, the object rotates around the center of gravity due to the rotational displacement of the bent part. As a result, the tip of the object is displaced in the width direction along the predetermined surface, but the center of gravity of the object does not move in translation, so that an actuator having a high control band and excellent high-speed tracking is obtained. In addition, since the expansion and contraction motion of the piezoelectric element is expanded through the column member, a large amount of displacement can be obtained.

  In the actuator according to the above aspect, it is preferable that the first beam member, the second beam member, and the column member are formed to a thickness of 50 μm or less. By setting these members to 50 μm or less, the size of the actuator can be reduced in the direction perpendicular to the predetermined plane. In addition, it is preferable to make these members thin to increase the amount of displacement of the bent portion.

  In the above aspect, the piezoelectric element has an active part that the interlayer electrodes of different polarities face each other and expands and contracts when a voltage is applied, and an inactive part that does not expand and contract when a voltage is applied, and the first beam member and It is preferable that the second beam member is configured to hold the piezoelectric element in the inactive portion. In this case, since the joint portion between the first and second beam members and the piezoelectric element does not expand or contract even when a voltage is applied, it can be favorably joined with an adhesive or the like.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In this embodiment, an example in which the actuator according to the present invention is applied to a magnetic head assembly of a magnetic disk device will be described.

(Magnetic disk unit)
FIG. 1 is a plan view showing a magnetic disk device 10 including a magnetic head assembly according to an embodiment of the present invention. As shown in FIG. 1, a magnetic disk device 10 includes a disk-shaped magnetic recording medium (magnetic disk) 11, a spindle motor (not shown) that rotates the magnetic recording medium 11, A slider 13 provided with a head (recording element and reproducing element) 16 (see FIG. 2 described later), a suspension arm (support member) 14 that supports the slider 13, and an electromagnetic actuator (voice coil motor) that drives the suspension arm 14 ) 15 and an electronic circuit (not shown) for recording and reproducing information on the magnetic recording medium 11 via the magnetic head 16.

  The magnetic recording medium 11 is fixed to a rotating shaft 12a of a spindle motor and is rotated at a high speed by the spindle motor. The suspension arm 14 includes a carriage arm 14a on the base end side (center axis 15a side) and a suspension 14b on the tip end side. The slider 13 is disposed on the magnetic recording medium 11 side of the gimbal 14c (see FIG. 2 described later) at the tip of the suspension 14b. The suspension arm 14 is driven and controlled by an electromagnetic actuator 15 and rotates within a predetermined angular range about a central axis 15a.

(Actuator)
FIG. 2 is a schematic diagram showing the slider 13, the actuator 20, and the suspension 14b. 3A to 3C are three views showing the shapes of the actuator 20 and the slider 13, FIG. 3A is a top view seen from the suspension 14 b side, and FIG. 3B is a view of the slider 13. FIG. 3C is a front view seen from the distal end side, and FIG. 3C is a side view of the actuator 20 seen from the right end side of FIG. In addition, in FIG. 2, the dashed-dotted line has shown the location where members are joined. In the following description, the direction of the arrow T in the figure is referred to as the upward (or downward) direction, the direction of the arrow W as the track width direction, and the arrow L as the length direction.

  As shown in FIGS. 2 and 3, the actuator 20 of the present embodiment includes a pair of piezoelectric elements 30 disposed on both sides of the slider 13, and a hinge (plate-like shape) disposed above the piezoelectric elements 30 and the slider 13. Member) 40. The slider 13 is disposed below the gimbal 14c provided at the tip of the suspension 14b via the hinge 40. The actuator 20 is joined to the lower surface of the gimbal 14c. Reference numeral 16 in FIG. 2 schematically shows a magnetic head (recording element and reproducing element) provided on the end surface of the slider 13 on the tip side. As the recording element, for example, a single pole head is used, and as the reproducing element, for example, an MR (Magneto Resistive) element, a GMR (Giant Magneto Resistive) element, or a TMR (Tunnel Magneto Resistive) element is used. These recording elements and reproducing elements are manufactured by repeating a film forming process and a patterning process.

  The piezoelectric element 30 has a stacked structure in which an interlayer electrode 32 is sandwiched between a plurality of piezoelectric films 31 as shown in FIGS. 2 and 3C. On both end faces of the piezoelectric element 30 in the length direction, there are formed common electrodes 35 connected to power supplies of different polarities (or one connected to the power supply and the other connected to the ground). . The common electrode 35 on one side (front end side, left side in FIG. 3C) is electrically connected to the even-numbered interlayer electrode 32 counted from the top, and the other side (base end side, FIG. 3C). The right common electrode 35 is electrically connected to the odd-numbered interlayer electrodes 32 counted from above. These common electrodes 35 are electrically connected to wiring (not shown) formed on the surface of the suspension 14b via an insulating material through a thin metal wire (not shown).

  As shown in FIG. 3C, the piezoelectric element 30 has an interlayer electrode 32 connected to different common electrodes 35 facing each other, and an active region D2 that expands and contracts in the length direction by application of voltage, and does not contribute to expansion and contraction. An active region D1 is formed. This inactive region D1 is located below a joint portion (shaded portions j and k in FIG. 2) of beam members 42 and 43 of the hinge 40 described later. The piezoelectric elements 30 are arranged on both sides of the slider 13 (both sides in the track width direction) with a predetermined interval (an interval that does not obstruct the rotational movement of the slider 13).

  The hinge 40 is made of a metal plate such as stainless steel. As shown in FIGS. 2 and 3, the hinge 40 includes a beam member 42 and a beam member 43 that extend in the track width direction, and a column member 41 that connects the beam member 42 and the beam member 43. As shown in FIGS. 2 and 3B, the beam member 42 is bonded to the pair of piezoelectric elements 30 by a bonding agent 33c at a proximal end side bonded portion (shaded portion j in FIG. 2). Further, the beam member 43 is joined to the pair of piezoelectric elements 30 by a bonding agent 33a at a joint portion on the front end side (shaded portion k in FIG. 2). Since the joint between the piezoelectric element 30 and the hinge 40 is provided in the inactive region D1 that does not expand or contract even when a voltage is applied to the piezoelectric element 30, it can be satisfactorily joined by the adhesives 33a and 33c.

  The column member 41 includes a distal end side column portion 41a and a proximal end side column portion 41c extending in a direction perpendicular to the beam members 42 and 43, and a crank connected to the end portions of the distal end side column portion 41a and the proximal end side column portion 41c. Part 41b. As shown in FIG. 3A, the distal side column part 41 a extends from the beam member 43, and the proximal side column part 41 c extends from the beam member 42. The crank portion 41b extends in the track width direction when stopped. As shown in FIG. 3A, the column member 41 is formed to be point-symmetric with respect to the center of the crank portion 41b. The column member 41 and the slider 13 are joined together by an adhesive 33b below the crank portion 41b (shaded portion 1 in FIG. 2). When the actuator 20 is viewed from above, the center of the crank portion 41 b overlaps the center of gravity of the slider 13.

  The hinge 40 is joined to the joint portion (shaded portion m in FIG. 2) of the suspension 14b (gimbal 14c) via the adhesive 33d above the beam member 42, whereby the actuator 20 is supported by the suspension 14b.

(Actuator and slider operation)
4A and 4B are schematic views showing the displacement of the slider accompanying the operation of the actuator.

  As shown in FIG. 4A, when no voltage is applied to the piezoelectric element 30, the distal end side column part 41 a and the proximal end side column part 41 b extend in a direction perpendicular to the beam member 42. In this case, the central axis of the slider 13 coincides with the direction in which the track of the magnetic disk extends (chain line EE ′).

  When a voltage is supplied to both the piezoelectric elements 30 via the common electrode 35, both the piezoelectric elements 30 contract in the length direction as indicated by an arrow A in FIG. The contraction length of the piezoelectric element 30 corresponds to the applied voltage.

  Since the proximal-side beam member 42 is fixed to the suspension 14 b, it is not displaced by the contraction of the piezoelectric element 30. On the other hand, since the beam member 43 on the distal end side is not fixed to the suspension 14b, the beam member 43 is pulled toward the beam member 42 side by contraction of the piezoelectric element 30 as shown in FIG. Although the column member 41 is deformed by the displacement of the beam member 43, the column member 41 is formed point-symmetrically with respect to the center of the crank portion 41b (which coincides with the center of gravity G of the slider 13). Forces in the opposite directions (arrow A1 and arrow A2) act on the respective end portions of 41b from the distal end side column portion 41a and the proximal end side column portion 41c. As a result, the crank portion 41b is displaced in the direction of rotation around the center (the center of gravity G of the slider 13) as indicated by an arrow B. Since the slider 13 is joined by the crank portion 41b, the slider 13 rotates around the center of gravity G due to the displacement of the crank portion 41b, and the center axis thereof changes as indicated by a chain line FF ′. As a result, the magnetic head 16 attached to the front end side of the slider 13 is displaced in the track width direction by a displacement amount C.

  That is, the column member 41 converts the expansion / contraction motion by the piezoelectric element 30 into a rotational motion centered on the center of gravity G of the slider 13. Further, since the driving by the column member 41 is performed in the vicinity of the center of gravity G (rotation center) of the slider 13, the displacement of the tip portion of the slider 13 on which the magnetic head is formed is enlarged. Thereby, a displacement amount (symbol C in FIG. 4B) larger than the conventional one can be obtained.

  In the above-described example, the case where the piezoelectric element 30 contracts has been described. However, when the piezoelectric element 30 extends, the slider 13 can be rotated in the opposite direction to the contraction.

  In the present embodiment, the suspension arm 14 is driven by the electromagnetic actuator 15 to determine the position of the slider 13, and the actuator 20 (consisting of a pair of piezoelectric elements 30 and a hinge 40) interposed between the suspension 14 b and the slider 13. ), The position of the magnetic head 16 is finely adjusted, so that the magnetic head can follow the track of the magnetic recording medium having a high track density.

  Further, in the present embodiment, the actuator 20 fixed to the suspension 14b (gimbal 14c) is displaced without rotating the center of gravity by rotating the slider 13 around the center of gravity, so that resonance is not excited. For this reason, it is possible to improve the high-speed followability by increasing the control band.

  Furthermore, in the present embodiment, the displacement of the piezoelectric element 30 is enlarged and converted to the rotational displacement of the tip of the slider 13 by the column member 41 that constitutes a part of the actuator 20, so that a larger amount of displacement than before can be obtained. it can.

  Further, in this embodiment, since the pair of piezoelectric elements 30 constituting a part of the actuator 20 are disposed on both sides of the slider 13, a space required in a direction perpendicular to the magnetic recording medium can be reduced, and the magnetic field can be reduced. It is not necessary to reduce the number of magnetic recording media to be mounted even in a magnetic disk device having a plurality of recording media.

(Production method)
Hereinafter, the manufacturing method of the actuator and the magnetic head assembly according to the present embodiment will be described with reference to FIG.

  First, a method for manufacturing the piezoelectric element 30 will be described. PNN (lead niobate niobate) -PT (lead titanate) -PZ (lead zirconate) can be used as the material of the piezoelectric film 31, and Pt (platinum) can be used as the material of the interlayer electrode 32. In addition to the above, the piezoelectric film 31 may be made of a piezoelectric material such as PZT (lead zirconate titanate). First, a PNN-PT-PZ ceramic green sheet is prepared, and a conductive paste containing Pt as a main component is screen-printed on the surface of the PNN-PT-PZ ceramic green sheet.

  Thereafter, a predetermined number of PNN-PT-PZ ceramic green sheets printed with this conductive paste are laminated and fired at 1050 ° C. in the atmosphere to form a piezoelectric laminated ceramic sheet. Next, this piezoelectric other laminated ceramic sheet is cut into a desired size to obtain a piezoelectric laminate. Finally, a conductor film such as Pt is formed on both end faces of the piezoelectric laminate to form the common electrode 35, thereby obtaining the piezoelectric element 30 shown in FIG. Note that PNN-PT-PZ is a piezoelectric material that is easily polarized by application of a voltage. Therefore, when this material is used for the piezoelectric film 31, it is not necessary to perform polarization treatment in advance. When this material is used for the piezoelectric film 31, the polarization direction is easily reversed, so that the piezoelectric element 30 changes only in the contraction direction even if the polarity of the voltage is changed.

  Next, the stainless steel plate is processed into a predetermined shape to form the hinge 40. The hinge 40 and the hatched portions j and k (see FIG. 2) of the piezoelectric element 30 are joined by the adhesive 33a and the adhesive 33c, and the hinge 40 (crank portion 41b) and the hatched portion 1 of the slider 13 (see FIG. 2). Are bonded with an adhesive 33b. Thereby, the actuator according to the present embodiment is completed.

  Then, the hinge 40 (beam member 42) and the hatched portion m (see FIG. 2) of the suspension 14b (gimbal 14c) are joined together by an adhesive 33d. In this way, a magnetic head assembly including the actuator 20 according to this embodiment is completed.

(Verification of displacement)
Hereinafter, the result of examining the displacement amount of the magnetic head of the magnetic head assembly according to the present embodiment will be described. A magnetic head assembly provided with the actuator and slider having the structure shown in FIG. 3 was designed with each part set as follows.

  The slider 13 has a length L1 of 850 μm, a width W5 of 700 μm, and a height T3 of 240 μm. The piezoelectric element 30 has a length L1 of 850 μm, a width W4 of 200 μm, and a height T2 of 200 μm. The piezoelectric element 30 is formed by laminating 11 layers of this piezoelectric film 31 and 10 layers of interlayer electrodes 32. The material of the piezoelectric film 31 was PNN-PT-PZ, and the thickness T4 of each layer was 20 μm. The thickness of the interlayer electrode 32 was 2 μm.

  The material of the hinge 40 was SUS (stainless steel), and the size thereof was 850 μm in length L1, 1110 μm in width W1, and 20 μm in thickness T1. In addition, the thickness of the hinge 40 should just be 50 micrometers or less. The smaller the thickness T1 of the hinge 40, the larger the displacement of the slider. However, the thickness is set to 20 μm in consideration of the ease of handling during manufacturing. Both the width L2 of the beam member 42 and the width L3 of the beam member 43 were 100 μm. The length L4 of the front end side column portion 41a and the length L4 ′ of the proximal end side column portion 41c of the column member 41 are both 300 μm, and the length W2 of the crank portion 41b is 150 μm. Further, the width W3 of the distal end side column portion 41a and the proximal end side column portion 41c and the width L5 of the crank portion 41b were both set to 50 μm.

  A simulation calculation was performed on the magnetic head assembly designed as described above, and the amount of displacement of the magnetic head arranged on the end face of the slider 13 was calculated. FIG. 5 is a diagram illustrating a result of simulating the displacement amount of the slider. From this simulation, it was confirmed that when a voltage of 30 [V] was supplied to both piezoelectric elements 30, the displacement of the magnetic head was 177 nm to 200 nm in the track width direction.

(Modification)
In the above-described embodiment, the example in which the actuator according to the present invention is applied to the magnetic head assembly has been described. However, the actuator according to the present invention is used for movement control of a minute range of a printer head of an ink jet printer or other information equipment components. May be.

  Moreover, although the case where the polarization process is not performed on the piezoelectric film 31 of the piezoelectric element 30 has been described as an example in the above-described example, the piezoelectric film 31 is driven in the expansion / contraction direction by performing the polarization process using a different material. You may do it.

  Hereinafter, various aspects of the present invention will be collectively described as supplementary notes.

  (Supplementary note 1) A pair of piezoelectric elements that are arranged on both sides in the width direction of an object and expand and contract in the front-rear direction of the object by applying a voltage, and hold the pair of piezoelectric elements at one end in the expansion and contraction direction In addition, the first beam member fixed to the support member and the pair of piezoelectric elements are held at the other end in the expansion / contraction direction, and the piezoelectric element expands and contracts to the first beam member side. A second beam member that is displaced so as to approach or leave, and a columnar member that has a crank-shaped bent portion, connects the first and second beam members, and supports the object. An actuator characterized by that.

  (Appendix 2) The actuator according to appendix 1, wherein the first beam member, the second beam member, and the column member are formed to a thickness of 50 μm or less.

  (Appendix 3) The actuator according to appendix 2, wherein the first beam member, the second beam member, and the column member are integrally formed of a metal plate.

  (Additional remark 4) The said piezoelectric element has a structure which laminated | stacked the sheet-like piezoelectric film and the interlayer electrode alternately, The actuator of Additional remark 1 characterized by the above-mentioned.

  (Supplementary Note 5) The piezoelectric element includes an active part that is opposed to an interlayer electrode having different polarities and expands and contracts when a voltage is applied, and an inactive part that does not expand and contract when a voltage is applied. The actuator according to appendix 1, wherein the second beam member holds the piezoelectric element in the inactive portion.

  (Appendix 6) A slider having a magnetic head for recording and reproducing information on a magnetic recording medium, a suspension for holding the slider, and a slider interposed between the slider and the suspension so that the slider is centered on the center of gravity. And a pair of actuators that are arranged on both sides in the width direction of the slider and expand and contract in the front-rear direction of the slider when a voltage is applied. The piezoelectric element, the pair of piezoelectric elements are held at one end in the expansion / contraction direction, the first beam member fixed to the suspension, and the pair of piezoelectric elements at the other end in the expansion / contraction direction And is displaced so as to approach or leave the first beam member side by expansion and contraction of the piezoelectric element. A second beam member, a crank-shaped bent portion, formed symmetrically with respect to the center of the bent portion, connecting the first and second beam members, and the center of the bent portion; A magnetic head assembly comprising: a columnar member that supports the slider at the bent portion so that a center of gravity of the slider coincides.

  (Appendix 7) A magnetic recording medium capable of magnetically recording information, a slider including a magnetic head for recording and reproducing information on the magnetic recording medium, a suspension holding the slider, the slider, and the suspension And an actuator for rotating the slider within a predetermined angle range about its center of gravity, and an activation means for driving the suspension to move the slider in the radial direction of the magnetic recording medium. The actuator is disposed on both sides in the width direction of the slider, and a pair of piezoelectric elements that expand and contract in the front-rear direction of the slider when a voltage is applied, and the pair of piezoelectric elements in the expansion and contraction direction. And a first beam member fixed to the suspension, A second beam member that holds the pair of piezoelectric elements at the other end in the front-rear direction, and that is displaced so as to approach or leave the first beam member side by expansion and contraction of the piezoelectric element; It has a bent portion, is formed point-symmetrically with respect to the center of the bent portion, connects the first and second beam members, and the center of the bent portion and the center of gravity of the slider coincide with each other. And a columnar member that supports the slider at the bent portion.

FIG. 1 is a plan view showing a magnetic disk device including a magnetic head assembly according to an embodiment of the present invention. FIG. 2 is a schematic diagram showing a slider, an actuator, and a suspension. 3A to 3C are three views showing the shape of the actuator, FIG. 3A is a top view seen from the suspension side, and FIG. 3B is a front view seen from the tip side of the slider. FIG. 3 (c) shows a side view as seen from the right end side of FIG. 3 (a). 4A and 4B are schematic views showing the displacement of the slider accompanying the operation of the actuator. FIG. 5 is a diagram illustrating a result of simulating the displacement amount of the slider.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Magnetic disk apparatus, 11 ... Magnetic recording medium (magnetic disk), 12a ... Rotating shaft, 13 ... Slider, 14 ... Suspension arm, 14a ... Carriage arm, 14b ... Suspension, 14c ... Gimbal, 15 ... Electromagnetic actuator, 15a ... Central axis, 16 ... magnetic head, 30 ... piezoelectric element, 31 ... piezoelectric film, 32 ... interlayer electrode, 33a-33d ... adhesive, 35 ... common electrode, 40 ... hinge (plate-like member), 41 ... column member, 41a ... distal end side column part, 41b ... crank part, 41c ... proximal end side column part, 42 ... proximal end side beam member (first beam member), 43 ... distal end side beam member (second beam member) .

Claims (5)

A pair of piezoelectric elements that are arranged on both sides in the width direction of the object and expand and contract in the front-rear direction of the object by application of a voltage;
Holding the pair of piezoelectric elements at one end in the expansion and contraction direction, and a first beam member fixed to the support member;
A second beam member that holds the pair of piezoelectric elements at the other end in the expansion / contraction direction, and that is displaced so as to approach or leave the first beam member side by expansion / contraction of the piezoelectric element;
A columnar member having a crank-shaped bend, connecting the first and second beam members, and supporting the object;
An actuator comprising:   2. The actuator according to claim 1, wherein the first beam member, the second beam member, and the column member are formed to a thickness of 50 μm or less.   The piezoelectric element includes an active part that is opposed to an interlayer electrode having different polarities and expands and contracts when a voltage is applied, and an inactive part that does not expand and contract when a voltage is applied, and the first beam member and the second beam The actuator according to claim 4, wherein the member holds the piezoelectric element in the inactive portion. A slider provided with a magnetic head for recording and reproducing information on a magnetic recording medium, a suspension for holding the slider, and a slider interposed between the slider and the suspension so that the slider is centered on its center of gravity. A magnetic head assembly having an actuator that rotates within a range, the actuator comprising:
A pair of piezoelectric elements disposed on both sides in the width direction of the slider and extending and contracting in the front-rear direction of the slider by application of a voltage;
Holding the pair of piezoelectric elements at one end in the expansion and contraction direction, and a first beam member fixed to the suspension;
A second beam member that holds the pair of piezoelectric elements at the other end in the expansion / contraction direction, and that is displaced so as to approach or leave the first beam member side by expansion / contraction of the piezoelectric element;
It has a crank-like bent part, is formed point-symmetrically with respect to the center of the bent part, connects the first and second beam members, and the center of the bent part and the center of gravity of the slider coincide with each other A columnar member that supports the slider at the bent portion;
A magnetic head assembly comprising: A magnetic recording medium capable of magnetically recording information, a slider including a magnetic head for recording and reproducing information on the magnetic recording medium, a suspension holding the slider, and between the slider and the suspension A magnetic disk device comprising an actuator for interveningly rotating the slider within a predetermined angle range centered on its center of gravity, and an activation means for driving the suspension to move the slider in the radial direction of the magnetic recording medium And the actuator is
A pair of piezoelectric elements disposed on both sides in the width direction of the slider and extending and contracting in the front-rear direction of the slider by application of a voltage;
Holding the pair of piezoelectric elements at one end in the expansion and contraction direction, and a first beam member fixed to the suspension;
A second beam member that holds the pair of piezoelectric elements at the other end in the expansion / contraction direction, and that is displaced so as to approach or leave the first beam member side by expansion / contraction of the piezoelectric element;
It has a crank-like bent part, is formed point-symmetrically with respect to the center of the bent part, connects the first and second beam members, and the center of the bent part and the center of gravity of the slider coincide with each other A columnar member that supports the slider at the bent portion;
A magnetic disk drive comprising:

Images