JP4319616B2 - Actuator, slider unit, suspension and hard disk drive - Google Patents

Description

  The present invention relates to an actuator, a slider unit, a suspension, and a hard disk device.

Conventionally, an actuator in the field of this technology is disclosed in, for example, Patent Document 1 below. The actuator described in this publication includes a pair of movable parts (arm parts), a fixed part (coupled part) coupled to each other on one end side of both movable parts, and a piezoelectric / electrostrictive element disposed outside the movable part. Device. And it attaches to the other end part side of a movable part so that a predetermined component may be clamped. In this actuator, the position of the fixed part is fixed by a predetermined method, and the piezoelectric / electrostrictive element is driven to bend the movable part to follow the movement of one end side of the movable part. Is displaced. In addition, the displacement of this component is a displacement along the direction orthogonal to the extending direction of a movable part, and is a substantially linear displacement.
JP 2002-299713 A

  Here, the greater the amount of displacement of the actuator, the smaller the drive power required to displace a component such as the head slider by a predetermined length. Therefore, from the viewpoint of power saving and energy saving, there has been a demand for an actuator that can obtain a large displacement with little power consumption.

  Accordingly, the present invention has been made to solve the above-described problems, and an object thereof is to provide an actuator, a slider unit, a suspension, and a hard disk device in which the displacement amount of the head slider is increased.

  The actuator according to the present invention includes a pair of arm portions extending substantially in parallel, a connecting portion connecting the pair of arm portions on one end side of each arm portion, and a pair extending substantially parallel to the arm portion from the connecting portion. And a pair of sliders mounted on the outer surface of each arm part and extending along the extending direction of the arm part. And a piezoelectric element.

  In this actuator, the head slider attached to the slider mounting portion is displaced when the piezoelectric element attached to the outer surface of the arm portion is driven. In this actuator, when the head slider is displaced, the other end portion side of the arm portion, that is, the side away from the connecting portion is fixed. Therefore, when the piezoelectric element is driven, the one end side of the arm portions connected to each other by the connecting portion is displaced. Then, the displacement of the head slider is realized by the displacement of the slider mounting portion extending from the connecting portion along with the displacement of the one end portion side of the arm portion. That is, this actuator can drive the head slider in a state where the arm portion on the side away from the connecting portion is fixed. Such an actuator has a larger displacement of the head slider than a conventional actuator.

  Further, when the outer width of the pair of arm portions is W (mm) and the length of each arm portion is L (mm), L / W is preferably 1.0 to 3.0. In this case, the actuator can obtain a sufficient amount of displacement.

  The piezoelectric element preferably has a plurality of piezoelectric layers and a plurality of electrode layers, and the piezoelectric layers and the electrode layers are preferably laminated alternately.

  Moreover, the arm part and the connection part may be made of single crystal silicon or may be made of a metal material.

  The slider unit according to the present invention includes a pair of arm portions extending substantially in parallel, a connecting portion connecting the pair of arm portions on one end side of each arm portion, and extending substantially parallel to the arm portion from the connecting portion. An actuator having a slider mounting portion interposed between the pair of arm portions, a pair of piezoelectric elements attached to the outer surface of each arm portion and extending along the extending direction of the arm portion, and a thin film magnetic head, And a head slider attached to the slider mounting portion of the actuator.

  In this slider unit, the head slider attached to the slider mounting portion is displaced by driving the piezoelectric element attached to the outer surface of the arm portion of the actuator. In this actuator, when the head slider is displaced, the other end portion side of the arm portion, that is, the side away from the connecting portion is fixed. Therefore, when the piezoelectric element is driven, the one end side of the arm portions connected to each other by the connecting portion is displaced. Then, the displacement of the head slider is realized by the displacement of the slider mounting portion extending from the connecting portion along with the displacement of the one end portion side of the arm portion. That is, this actuator can drive the head slider in a state where the arm portion on the side away from the connecting portion is fixed. A slider unit including such an actuator has a larger displacement of the head slider than a slider unit including a conventional actuator.

  The suspension according to the present invention includes a head slider on which a thin film magnetic head is formed, a pair of arm portions extending substantially in parallel, a connecting portion that connects the pair of arm portions on one end side of each arm portion, and a connecting portion. Extending substantially parallel to the arm part and interposed between the pair of arm parts, the slider mounting part to which the head slider is attached, and the outer side surface of each arm part, respectively, and along the extending direction of the arm part An actuator having a pair of extending piezoelectric elements, a spring plate on which the actuator is mounted on the main surface and the arm portion is fixed on the other end side of each arm portion of the actuator, and a predetermined distance from the spring plate And a load beam for cantilevering the spring plate.

  In this suspension, the head slider attached to the slider mounting portion is displaced by driving the piezoelectric element attached to the outer surface of the arm portion of the actuator. In this actuator, the other end portion side of the arm portion, that is, the side away from the connecting portion is fixed to the spring plate. Therefore, when the piezoelectric element is driven, the one end side of the arm portions connected to each other by the connecting portion is displaced. Then, the displacement of the head slider is realized by the displacement of the slider mounting portion extending from the connecting portion along with the displacement of the one end portion side of the arm portion. That is, this actuator can drive the head slider in a state where the arm portion on the side away from the connecting portion is fixed. A suspension having such an actuator has a larger displacement of the head slider than a suspension having a conventional actuator.

  Moreover, it is preferable that the load beam has a surface portion facing the back surface of the spring plate, and a protrusion protruding toward the slider mounting portion is formed at a position corresponding to the slider mounting portion of the actuator of the surface portion. That is, even if the spring plate on which the actuator is mounted is bent and force is applied from the protrusion formed on the load beam to the slider mounting portion, this suspension can reduce the stress concentration at the arm portion. Therefore, the situation where the actuator is damaged is significantly reduced.

  A hard disk device according to the present invention is a hard disk device including a recording medium, a head slider on which a thin film magnetic head facing the recording medium is formed, and an actuator for driving the head slider, and the actuator extends substantially in parallel. A pair of arm portions, a connecting portion for connecting the pair of arm portions on one end side of each arm portion, a head slider extending substantially parallel to the arm portion from the connecting portion and interposed between the pair of arm portions; And a pair of piezoelectric elements that are attached to the outer surface of each arm part and extend along the extending direction of the arm part.

  In this hard disk device, the head slider attached to the slider mounting portion is displaced by driving the piezoelectric element attached to the outer surface of the arm portion of the actuator. In this actuator, when the head slider is displaced, the other end portion side of the arm portion, that is, the side away from the connecting portion is fixed. Therefore, when the piezoelectric element is driven, the one end side of the arm portions connected to each other by the connecting portion is displaced. Then, the displacement of the head slider is realized by the displacement of the slider mounting portion extending from the connecting portion along with the displacement of the one end portion side of the arm portion. That is, this actuator can drive the head slider in a state where the arm portion on the side away from the connecting portion is fixed. A hard disk device provided with such an actuator has a larger displacement of the head slider than a hard disk device provided with a conventional actuator.

  According to the present invention, there are provided an actuator, a slider unit, a suspension, and a hard disk device in which the displacement amount of the head slider is increased.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, embodiments that are considered to be the best for carrying out an actuator, a slider unit, a suspension, and a hard disk device according to the invention will be described in detail with reference to the accompanying drawings. In addition, the same code | symbol is attached | subjected about the same or equivalent element, and the description is abbreviate | omitted when description overlaps.

  FIG. 1 is a schematic configuration diagram showing the hard disk device of the present embodiment. The hard disk device 1 includes a hard disk 12 as a recording medium and a head stack assembly (HSA) 20 having a head slider (hereinafter simply referred to as a slider) SL in a housing 10. The slider SL is a component for reading the magnetic recording information from the hard disk 12 and recording the magnetic recording information on the hard disk 12, and illustration of a slider rail and the like for adjusting the flying height from the hard disk 12 is omitted. ing. Further, the hard disk device 1 is provided with a control unit 14 that performs various controls such as recording and reproduction of information on the hard disk 12 and a ramp mechanism 16 for retracting the slider SL from the hard disk 12. Further, the hard disk 12 is rotated by a spindle motor (not shown).

  The head stack assembly 20 is an assembly composed of an actuator arm 22 rotatably supported around a spindle 18 by a voice coil motor (VCM), and a suspension 24 connected to the actuator arm 22. A plurality of layers are stacked in the depth direction. A slider SL is attached to the tip of the suspension 24 so as to face the hard disk 12.

  Next, the holding state of the slider SL in the hard disk device 1 will be described with reference to FIGS.

  The slider SL has a substantially rectangular parallelepiped shape with a width of 0.7 mm, a length of 0.85 mm, and a thickness of 0.23 mm, and the thin film magnetic head H formed in the slider SL faces the hard disk 12 with air. It is exposed on the bearing surface (ABS). The position of the slider SL in this embodiment is controlled by a two-stage servo control system, and the position is controlled not only by the VCM but also by the actuator 30. The actuator 30 is a device that controls the position of the slider SL more finely than the VCM, and displaces the slider SL relative to the load beam 26 of the suspension 24. That is, the suspension 24 is rotated by the voice coil motor when the slider SL is moved relatively large, and the actuator 30 is driven when the slider SL is slightly moved.

  The actuator 30 includes a silicon frame 32 and a pair of piezoelectric elements 34A and 34B.

  The silicon frame 32 is integrally formed of single crystal silicon, and has a substantially E-shaped cross section in which two parallel slits are formed from one end face of the rectangular parallelepiped. Specifically, the silicon frame 32 includes a pair of arm portions 36A and 36B extending in parallel, a connecting portion 38 connecting the arm portions 36A and 36B, and a connecting portion so as to be interposed between the arm portions 36A and 36B. The slider mounting part 40 extended from 38 is comprised.

  Each arm portion 36A, 36B has a strip shape of length (L) 1.5 mm × width 0.1 mm × thickness 0.2 mm, and the main surfaces 36a face each other. A connecting portion 38 having a rectangular parallelepiped shape of width 0.75 mm × length 0.5 mm × thickness 0.2 mm is interposed between one end portion 36b of each arm portion 36A, 36B, and this connecting portion 38 is an arm. The one end portions 36b and 36b of the portions 36A and 36B are connected to each other. The slider mounting portion 40 having a rectangular parallelepiped shape having a width of 0.45 mm, a length of 1.0 mm, and a thickness of 0.2 mm is provided in the same direction as the extending direction of the arm portions 36A and 36B from the connecting portion 38. It extends to the other end 36c of 36B. The slider SL is mounted at a position from the free end of the slider mounting portion 40 so that it slightly protrudes (for example, 0.3 mm) from the free end of the slider mounting portion 40, and by an adhesive. It is fixed.

  The piezoelectric elements 34A and 34B of the actuator 30 cover the entire outer surface 36d of the arm portions 36A and 36B over the entire length of the arm portions 36A and 36B on the outer surfaces (opposite surfaces of the main surface 36a) 36d of the arm portions 36A and 36B. In this way, it is bonded with an adhesive such as epoxy, silicone or acrylic. The piezoelectric elements 34A and 34B have a single plate structure with a width of 0.15 mm, a length of 1.5 mm, and a thickness of 0.2 mm. Electrodes 34b and 34b are respectively provided on the front and back surfaces of a piezoelectric ceramic body 34a such as PZT. Is formed. The piezoelectric elements 34A and 34B are rectangular plates extending in one direction, and are attached so that the longitudinal direction thereof is along the extending direction (longitudinal direction) of the arm portions 36A and 36B. Thereby, the displacement of the piezoelectric elements 34A and 34B when a predetermined voltage is applied between the electrodes 34b and 34b can be effectively transmitted to the arm portions 36A and 36B.

  The slider unit 42 with the slider SL attached to the actuator 30 is installed on a gimbal (spring plate) 28 that is cantilevered by the load beam 26 of the suspension 24 as shown in FIGS. . More specifically, the slider unit 42 is mounted on the mounting surface 28 b of the tongue portion 28 a of the gimbal 28 and is fixed by an adhesive 44. The adhesive 44 is applied only to the other end portion 36c of each of the arm portions 36A and 36B and a part of the piezoelectric elements 34A and 34B around the other end portion 36c. The back surface 28c of the tongue portion 28a of the gimbal 28 and the gimbal facing surface portion (surface portion) 27 of the load beam 26 face each other with a predetermined distance therebetween, and the slider mounting portion 40 of the gimbal facing surface portion 27 faces the slider mounting portion 40. A dimple (projection) 26 a for restricting excessive displacement of the tongue portion 28 a of the gimbal 28 in the direction of the load beam 26 is formed at a corresponding position so as to protrude in the direction of the slider mounting portion 40.

  Next, the driving of the actuator 30 will be described with reference to FIG.

  As described above, in the actuator 30, the arm portions 36A and 36B and the piezoelectric elements 34A and 34B on the other end portion 36c side of the arm portions 36A and 36B are connected to the gimbal 28 (see FIG. 5A). When a voltage is applied so as to extend with respect to one piezoelectric element 34A and a voltage is applied so as to shorten with respect to the other piezoelectric element 34B, the one end 36b side of the arm parts 36A, 36B is in the same direction ( It is displaced in the direction of arrow A in the figure (see FIG. 5B). Then, a force in a direction from the piezoelectric element 34A to the piezoelectric element 34B is applied to the connecting portion 38 of the silicon frame 32, and the connecting portion 38 is also displaced in the same direction as the displacement direction of the arm portions 36A and 36B. At this time, the connecting portion 38 is inclined by an angle θ with respect to the original state.

  When the connecting portion 38 is inclined in this way, the slider mounting portion 40 that is not bonded to the gimbal 28 is inclined by the angle θ according to the inclination of the connecting portion 38. Accordingly, the slider SL mounted on the slider mounting portion 40 is displaced so as to rotate, and the center position of the tip of the slider SL moves from the point P to the point Q by the distance D1. Thus, in this actuator 30, the head slider SL can be driven by fixing the arm portions 36A, 36B on the side away from the connecting portion 38 (that is, the other end portion 36c side). .

  Here, the driving of the conventional actuator will be described with reference to FIGS.

  The conventional actuator 50 includes a silicon frame 52 and the pair of piezoelectric elements 34A and 34B described above. The silicon frame 52 is integrally formed in a substantially U shape, and connects the pair of arm portions 54A and 54B extending in parallel to the pair of arm portions 54A and 54B on the one end portion 54a side of the arm portions 54A and 54B. It is comprised with the connection part 56 to do. Each arm part 54A, 54B has a strip shape of length (L) 1.5 mm × width 0.05 mm × thickness 0.2 mm. The connecting portion 56 has a rectangular parallelepiped shape with a width of 0.75 mm, a length of 0.5 mm, and a thickness of 0.2 mm, and the arm portions 54A and 54B protrude in parallel from both sides thereof. . The slider SL is fixed to the inner side surface 54c of each arm portion 54A, 54B by an adhesive 55 so that the slider SL is sandwiched between the other end portions 54b of the arm portions 54A, 54B. In the actuator 50, the adhesive 44 is applied only to the connecting portion 56 in order to drive the slider SL (see FIG. 7A).

  When a voltage is applied to the one piezoelectric element 34A so as to be shortened and a voltage is applied to the other piezoelectric element 34B so as to extend, the slider SL held between the arm portions 54A and 54B The arm portions 54A and 54B are translated in the direction of arrow C in FIG. 7 (direction substantially perpendicular to the longitudinal direction of the arm portions 54A and 54B in the arrangement plane of the two arm portions 54A and 54B). At this time, the center position of the tip of the slider SL moves from the point R to the point S by a distance (displacement amount) D2.

  The inventors have found that the amount of displacement of the slider SL by the actuator 30 according to the present embodiment can be increased more than the amount of displacement of the slider SL by the conventional actuator 50 after intensive studies. That is, it has been found that the displacement amount D1 of the actuator 30 is larger than the displacement amount D2 of the actuator 50 when a predetermined voltage is applied to the piezoelectric elements 34A and 34B. Specifically, as shown in FIG. 8, a slider SL displacement amount comparison test was performed using actuators 30 </ b> A to 30 </ b> D having different dimensions and a conventional actuator 50. Here, each of the actuator 30A shown in FIG. 8A, the actuator 30B shown in FIG. 8B, the actuator 30C shown in FIG. 8C, and the actuator 30D shown in FIG. , 36B has a length L of 1.50 mm. In addition, the actuator 30A and the actuator 30B have a connecting portion 38 having a length of 0.30 mm, and the actuator 30C and the actuator 30D have a connecting portion 38 having a length of 0.50 mm. Furthermore, the actuator 30A and the actuator 30C have a separation distance (outer width) W of the outer surfaces of the piezoelectric elements 34A and 34B of 1.05 mm and a width of the slider mounting portion 40 of 0.35 mm. In the actuator 30D, the outer width W of the piezoelectric elements 34A and 34B is 0.90 mm, and the width of the slider mounting portion 40 is 0.20 mm.

  Further, as shown in the table of FIG. 9, a total of 12 actuator samples are prepared by varying the outer width W of the piezoelectric elements 34A and 34B, the lengths (L) of the arm portions 36A and 36B, and the connecting portion lengths. The displacement amount was compared with the comparative sample which is the actuator 50. Specifically, the same amount of voltage was applied to each sample, and the amount of displacement at the center position (point P, point S) of the slider SL tip was measured. The results are as shown in the table of FIG. 9 and the graph of FIG. Here, FIG. 10 is a graph showing the relationship between the displacement of each actuator, the arm length L, and the ratio (L / W) between the outer widths of the piezoelectric elements 34A and 34B. In the graph of FIG. 10, the vertical axis represents the displacement (μm), and the horizontal axis represents the L / W ratio.

  From the table of FIG. 9 and the graph of FIG. 10, an actuator similar to the actuator 30 described above (that is, samples 1 to 12) is compared with the conventional actuator 50 (even if the L / W ratio is the same). It can be seen that the displacement amount is large. It can also be seen that the actuator 30 having a higher L / W ratio exhibits a larger displacement. This is because the value obtained by dividing the minute extension amount ΔL proportional to the arm length L by the outer width W of the piezoelectric element is sin θ, and this sin θ and the displacement amount D1 of the slider SL are in a proportional relationship. This is because the displacement amount D1 and the L / W ratio are approximately proportional to each other. Therefore, in order to increase the amount of displacement, it is preferable to increase the L / W ratio, and more preferably in the range of 1.0 to 3.0. That is, when the L / W ratio is in the range of 1.0 to 3.0, the displacement of the actuator having the above dimensions becomes 0.50 μm or more, and the track density reaches 50 KPTI (50,000 tracks in 1 inch width). The actuator can be used.

  In the graph of FIG. 10, an approximate line of a sample having a connecting portion length of 0.5 mm is indicated by a solid line, and an approximate line of a sample having a connecting portion length of 0.3 mm is indicated by a broken line. From these two approximate lines, it can be seen that the shorter the connecting portion length, the larger the inclination (that is, the rate of increase of the displacement amount with respect to the L / W ratio is higher).

  As described in detail above, in the actuator 30 and the actuators 30A to 30D, the other end portion 36c side of the arm portions 36A and 36B is fixed to the gimbal 28 and attached to the outer side surface 36d of the arm portions 36A and 36B. By driving the piezoelectric elements 34A and 34B, the head slider SL attached to the slider mounting portion 40 is displaced. And as above-mentioned, such an actuator 30, 30A-30D can increase the displacement amount of the slider SL compared with the conventional actuator 50. As shown in FIG. The reason for this is that the displacement in the conventional actuator 50 is mainly due to the parallel movement, whereas the displacement in the actuators 30, 30A to 30D according to the present embodiment is mainly around the coupling portion 38 as the rotation center. This is considered to be due to rotational movement. That is, by switching the micro drive of the piezoelectric elements 34A and 34B to the rotational drive of the connecting portion 38, the slider SL mounted away from the connecting portion 38 on the slider mounting portion 40 interlocking with the connecting portion 38 is greatly displaced. . Therefore, the amount of displacement can be further increased by appropriately increasing the amount of protrusion of the slider SL from the slider mounting portion 40.

  Incidentally, the conventional actuator 50 also has the following technical problems.

  That is, since the conventional actuator 50 has a structure in which the slider SL is bonded and fixed to the inner side surface 54c of the arm portions 54A and 54B, the amount of the adhesive used for the bonding varies and the application position of the adhesive varies. In other words, the dynamic characteristics of the actuator 50 vary, making it difficult to control the actuator 50 with high accuracy. Therefore, in order to obtain the highly accurate actuator 50, a robot system provided with a precise dispenser is required, and installation thereof requires a great deal of labor and cost. On the other hand, since the actuator 30 employs a mounting method of mounting on the slider mounting portion 40, the influence of the adhesive supply amount is less than that of a conventional mounting method in which the actuator 30 is bonded to the inner surface of the arm portion. Therefore, it is no longer necessary to use a highly accurate adhesive supply device such as the robot system.

  As shown in FIGS. 4 and 11A, a dimple 26a for stabilizing the flying of the slider SL is formed on the gimbal facing surface portion 27 of the load beam 26 facing the lower surface 28c of the gimbal 28. When an impact is applied to the slider SL from the ABS side, the slider SL is displaced in the direction of the load beam 26. At this time, a large force due to the dimple 26a acts on the portion corresponding to the dimple 26a of the slider SL, and a bending moment is generated at the ends of the arm portions 54A and 54B to which the slider SL is bonded and fixed. , 54B warp to the load beam 26 side (see FIG. 11B). That is, in the conventional actuator 50, when an impact is applied to the slider SL from the ABS side, the arm portions 54A and 54B are bent with the dimple 26a as a fulcrum, and in the vicinity of the bonded portion between the slider SL and the arm portions 54A and 54B. As a result, a very large stress is generated, and in some cases, the arm portions 54A and 54B and the piezoelectric elements 34A and 34B may be destroyed. Although it is conceivable to reduce the stress in the arm portions 54A and 54B by increasing the thickness of the arm portions 54A and 54B and the piezoelectric elements 34A and 34B, the displacement amount of the slider SL is reduced due to the increase in rigidity. I will. On the other hand, in the actuator 30, even when a force is applied to the slider mounting portion 40 corresponding to the dimple 26a, the unconstrained connecting portion 38 side floats as shown in FIG. No moment is generated. Therefore, the stress concentration in the arm portions 36A and 36B at the time of impact is sufficiently relaxed, and the situation where the actuator 30 is damaged is significantly reduced. Further, the portions where the maximum stresses of the arm portions 36A and 36B are generated are the boundary portions between the arm portions 36A and 36B and the connecting portion 38, and the position from the dimple 26a is far away. Therefore, the stress generated in the slider mounting portion 40 is smaller than in the conventional case. That is, the impact resistance of the actuator 30 is greatly improved as compared with the prior art.

  The actuator 30 described above can be manufactured by, for example, the manufacturing method shown below.

First, in manufacturing the actuator 30, a single crystal silicon substrate 60 is prepared (see FIG. 13A). This silicon substrate 60 is to be the silicon frame 32 described above, and the surface orientation of the surface 60a is the (110) plane. For simplicity of explanation, only a part of the silicon substrate 60 is shown in the figure. Next, a SiN film 62 is formed on the front surface 60a and the back surface 60b of the silicon substrate 60 by using any one of a thermal oxidation method, a CVD method, and sputtering (see FIG. 13B). Incidentally, before forming the SiN film 62 may be a SiO ₂ film on the surface 60a and rear surface 60b.

  Then, using a known photolithography technique and etching technique, the SiN film 62 formed on the surface 60a of the silicon substrate 60 is partially removed, and slits 64A to 64D extending in a direction parallel to the (111) plane are formed. It forms (refer FIG.13 (c)). The width of the slider mounting portion 40 is defined by the distance between the two inner slits 64B and 64C, and the width of each of the two slits 64B and 64C is between the slider mounting portion 40 and the arm portions 36A and 36B. The separation distance is defined. Further, the widths of the arm portions 36A and 36B are defined by the distance between the inner two slits 64B and 64C and the outer two slits 64A and 64D. Subsequently, using the SiN film 62 as a mask, the silicon substrate 60 is etched with a KOH solution having a concentration of 40% and a temperature of 60 ° C. to form grooves 66A to 66D in regions corresponding to the slits 64A to 64D (FIG. 13D). )reference).

  This etching process is so-called anisotropic etching in which the etching rate varies depending on the plane orientation of the silicon substrate 60, and the etching rate on the (110) plane is much higher than the etching rate on the (111) plane. Therefore, the etching in the thickness direction of the silicon substrate 60 proceeds at a relatively high speed by the above-described etching process. Thereby, the silicon substrate 60 in a region where the SiN film 62 is not formed is etched away in the thickness direction. On the other hand, since the etching rate on the (111) plane, which is a plane orthogonal to the grooves 66A to 66D, is very slow, the (111) plane becomes the sidewall surface of each of the grooves 66A to 66D.

  Next, using a dicing saw, a slicer, a wire saw or the like, the silicon substrate 60 is cut along the inner side surfaces of the two outer grooves 66A and 66D, and the cross-sectional shape of the silicon substrate 60 is an E-shaped block. 68 is cut out (see FIG. 13E). Then, an elongated strip-shaped piezoelectric element elongated body 70 is attached to the outer wall surfaces 68a on both sides of the block 68 using an epoxy adhesive, and is heated and cured (see FIG. 13F). Finally, by using a wire saw, a dicing saw or the like, the block 68 to which the piezoelectric element long body 70 is attached is cut in a direction perpendicular to the grooves 66B and 66C, thereby completing the production of the actuator 30 described above ( (Refer FIG.13 (g)). That is, by cutting the block 68, the piezoelectric element long body 70 becomes the piezoelectric elements 34A and 34B of the actuator 30, and the portions to which the piezoelectric elements 34A and 34B are attached become the arm portions 36A and 36B and are sandwiched between the grooves 66B and 66C. This portion becomes the slider mounting portion 40, and the remaining portion becomes the connecting portion 38.

  By using single crystal silicon as the constituent material of the actuator 30 as in the manufacturing method described above, crystal defects are reduced in the arm portions 36A and 36B, thereby controlling the arm portions 36A and 36B with high accuracy. can do. In addition, since single crystal silicon elastically deforms without being plastically deformed in the operating temperature range of the hard disk device, an actuator with high controllability can be realized.

  In addition, the actuator 30 uses a photolithographic technique capable of fine processing and a micromachining technique used in a semiconductor manufacturing process or the like, so that the actuator 30 can be reduced in size and used for a pico slider, a femto slider, or the like. I can. Furthermore, since the silicon frame 32 can be integrally formed by using the photolithography technique, the manufacturing is easy. In addition, unlike the case where the metal frame actuator is integrally formed, it can be said that the manufacturing is easy because the arm portion does not need to be bent.

  Further, by manufacturing this structure by etching a single crystal substrate of silicon, it becomes very high precision and inexpensive. If the substrate has a <110> plane orientation of silicon, the <111> plane exists in a direction perpendicular thereto. Therefore, by patterning an etching mask so that this surface becomes the side wall surface of the arm portions 36A and 36B and etching with KOH or TMAH, a highly accurate actuator 30 can be obtained.

  Moreover, the actuator 30E similar to the actuator 30 can also be produced with the metal frame using a metal block. In this case, first, when producing the actuator 30E, a metal block 80 such as stainless steel (SUS430) is prepared (see FIG. 14A). Next, the metal block 80 is processed into a block 82 having a convex cross section by etching, cutting, or the like (see FIG. 14B). On both side surfaces of the block 82, an elongated strip-like thin plate 84 (thickness 50 μm) made of stainless steel to be the arm portions 36A and 36B and the piezoelectric element long body 70 to be the piezoelectric elements 34A and 34B are bonded with an epoxy adhesive. And then heat-cured (see FIG. 14C). Finally, by using a wire saw or the like, the block 82 to which the thin plate 84 and the piezoelectric element long body 70 are attached is cut to complete the production of the actuator 30E (see FIG. 14D).

  Since the actuator 30E having a metal frame is excellent in springiness, it is suitable for increasing the displacement amount of the slider SL. In addition, metals such as stainless steel are easy to manufacture because they have better workability than other materials.

  The present invention is not limited to the above embodiment, and various modifications are possible. For example, the arm portion and the connecting portion of the actuator are not necessarily integrated, and may be separated as appropriate. In addition, the piezoelectric element may be appropriately changed from a single-plate structure piezoelectric element to a multilayer stacked structure piezoelectric element. That is, as shown in FIG. 15, in each of the piezoelectric elements 35A and 35B having a multilayer structure, the internal electrodes 35b and 35c are alternately stacked inside the piezoelectric ceramic body 35a. The end portions of the internal electrodes 35b are exposed at one end face of the piezoelectric ceramic body 35a, and these are connected to the external electrodes 35d. On the other hand, the end of each internal electrode 35c is exposed on the other end face of the piezoelectric ceramic body 35a, and these are connected to the external electrode 35e. Furthermore, the frame of the actuator is not limited to a silicon frame or a metal frame, but may be a zirconia frame or the like.

1 is a diagram showing a configuration of a hard disk device according to an embodiment of the present invention. It is the perspective view which showed the slider unit which concerns on embodiment of this invention. FIG. 3 is an exploded perspective view of the slider unit of FIG. 2. FIG. 4 is a sectional view taken along line IV-IV of the slider unit of FIG. 2. (A) is the figure which showed the actuator before a deformation | transformation, (b) is the figure which showed the actuator after a deformation | transformation. It is the perspective view which showed the conventional actuator. (A) is the figure which showed the actuator before a deformation | transformation, (b) is the figure which showed the actuator after a deformation | transformation. It is the figure which showed the actuator from which the dimension differs from the actuator shown in FIG. It is the table | surface which showed the dimension value of each actuator from which a dimension differs including the actuator shown in FIG. FIG. 10 is a graph showing the results of a comparative test for each actuator shown in FIG. 9. FIG. (A) is the figure which showed the conventional actuator before a deformation | transformation, (b) is the figure which showed the conventional actuator after a deformation | transformation. FIG. 4 is a cross-sectional view taken along line IV-IV showing a state where the actuator shown in FIG. 2 is deformed. It is the figure which showed the manufacturing method using a single crystal silicon. It is the figure which showed the manufacturing method using a metal block. It is the figure which showed the aspect using a lamination type piezoelectric element.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Hard disk apparatus, 12 ... Hard disk, 24 ... Suspension, 26 ... Load beam, 26a ... Dimple, 27 ... Gimbal opposing surface part, 28 ... Gimbal, 30, 30A, 30B, 30C, 30D, 30E ... Actuator, 34A, 34B, 35A, 35B: Piezoelectric element, 36A, 36B: Arm portion, 38: Connection portion, 40: Slider mounting portion, 42: Slider unit, H: Thin film magnetic head, SL: Head slider.

Claims (9)

A pair of arm portions extending substantially in parallel;
A connecting portion for connecting the pair of arm portions on one end side of each of the arm portions;
A slider mounting portion to which a head slider on which a thin film magnetic head is formed is attached, extending between the pair of arm portions and extending substantially parallel to the arm portion from the coupling portion;
An actuator comprising a pair of piezoelectric elements attached to the outer surface of each arm part and extending along the extending direction of the arm part.   The L / W is 1.0 to 3.0, where W (mm) is the outer width of the pair of arm portions and L (mm) is the length of each arm portion. Actuator.   The actuator according to claim 1, wherein the piezoelectric element has a plurality of piezoelectric layers and a plurality of electrode layers, and the piezoelectric layers and the electrode layers are alternately stacked.   The actuator according to any one of claims 1 to 3, wherein the arm portion and the connecting portion are made of single crystal silicon.   The actuator according to claim 1, wherein the arm part and the connection part are made of a metal material. A pair of arm portions extending substantially in parallel, a connecting portion connecting the pair of arm portions on one end side of each of the arm portions, and the pair of arms extending substantially parallel to the arm portion from the connecting portion. An actuator having a slider mounting part interposed between the parts and a pair of piezoelectric elements attached to the outer surface of each arm part and extending along the extending direction of the arm part,
A slider unit having a thin film magnetic head and a head slider attached to the slider mounting portion of the actuator. A head slider on which a thin film magnetic head is formed;
A pair of arm portions extending substantially in parallel, a connecting portion connecting the pair of arm portions on one end side of each of the arm portions, and the pair of arms extending substantially parallel to the arm portion from the connecting portion. An actuator having a slider mounting portion to which the head slider is attached and a pair of piezoelectric elements attached to the outer side surfaces of the arm portions and extending along the extending direction of the arm portions. When,
A spring plate on which the actuator is mounted on a main surface and the arm portion is fixed on the other end side of each arm portion of the actuator;
A suspension comprising a load beam that cantilever-supports the spring plate in a state of being separated from the spring plate by a predetermined distance.   The load beam has a surface portion that faces the back surface of the spring plate, and a protrusion that protrudes toward the slider mounting portion is formed at a position corresponding to the slider mounting portion of the actuator on the surface portion. The suspension according to claim 7. A hard disk device comprising: a recording medium; a head slider on which a thin film magnetic head facing the recording medium is formed; and an actuator for driving the head slider,
The actuator is
A pair of arm portions extending substantially in parallel;
A connecting portion for connecting the pair of arm portions on one end side of each of the arm portions;
A slider mounting portion that extends substantially parallel to the arm portion from the connecting portion, is interposed between the pair of arm portions, and to which the head slider is attached;
A hard disk device having a pair of piezoelectric elements attached to the outer surface of each arm part and extending along the extending direction of the arm part.

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