Patent ID: 12198736

DETAILED DESCRIPTION

In general, according to one embodiment, a disk device includes a magnetic disk, an arm, a base, a flexure, a magnetic head, and damper. The arm is configured to rotate about a rotation axis. The base plate has a first surface facing the arm, and is attached to the arm away from the rotation axis in a first direction orthogonal to the rotation axis. The load beam is attached to the base plate, and has a second surface and a third surface. The second surface faces the magnetic disk. The third surface is opposite the second surface and is inclined with respect to the first surface so as to be closer to the magnetic disk as is further away from the arm. The flexure is attached to the second surface. The magnetic head is mounted on the flexure further away from the rotation axis than the base plate in the first direction, and is configured to read and write information from and to the magnetic disk. The damper is attached to the third surface, and includes a first constrained layer and a second constrained layer. The second constrained layer is located further away from the load beam than the first constrained layer. An end of the second constrained layer is located further away from the rotation axis than an end of the first constrained layer in the first direction, the ends of the first constrained layer and the second constrained layer being in a second direction opposite to the first direction.

First Embodiment

Hereinafter, a first embodiment will be described with reference toFIGS.1to7. In the present specification, components according to embodiments and descriptions of the components may be described in a plurality of expressions. The components and the description thereof are examples, and are not limited by the expression of the present specification. Components may also be identified with names different from those herein. In addition, the component may be described by an expression different from the expression in the present specification.

FIG.1is an exemplary perspective view illustrating a hard disk drive (HDD)10according to a first embodiment in an exploded manner. The HDD10is an example of a disk device, and may also be referred to as an electronic device, a storage device, an external storage device, or a magnetic disk device.

As illustrated inFIG.1, in the present specification, an X axis, a Y axis, and a Z axis are defined for convenience. The X axis, the Y axis, and the Z axis are orthogonal to each other. The X axis is provided along the width of the HDD10. The Y axis is provided along the length of the HDD10. The Z axis is provided along the thickness of the HDD10.

Furthermore, in the present specification, an X direction, a Y direction, and a Z direction are defined. The X direction is a direction along the X axis and includes a +X direction indicated by an arrow of the X axis and a −X direction which is an opposite direction of the arrow of the X axis. The Y direction is a direction along the Y axis and includes a +Y direction indicated by an arrow of the Y axis and a −Y direction which is an opposite direction of the arrow of the Y axis. The Z direction is a direction along the Z axis and includes a +Z direction indicated by an arrow of the Z axis and a −Z direction which is an opposite direction of the arrow of the Z axis.

As illustrated inFIG.1, the HDD10includes a housing11, a plurality of magnetic disks12, a spindle motor13, a head stack assembly (HSA)14, a voice coil motor (VCM)15, a ramp load mechanism16, and a printed circuit board (PCB)17. The HDD10is not limited to this example.

The housing11includes a base21, an inner cover22, and an outer cover23. Each of the base21, the inner cover22, and the outer cover23is made of metal such as aluminum alloy, for example.

The base21has a substantially rectangular parallelepiped box shape opened in the +Z direction. The plurality of magnetic disks12, the spindle motor13, the HSA14, the VCM15, and the ramp load mechanism16are housed inside the base21.

The base21has a bottom wall25and a side wall26. The bottom wall25has a substantially rectangular (quadrangular) plate shape and stands substantially orthogonal to the Z direction. The side wall26protrudes in the substantially +Z direction from the edge of the bottom wall25and has a substantially rectangular frame shape. The bottom wall25and the side wall26are integrated together.

The inner cover22is attached to the end of the side wall26in the +Z direction with, for example, a screw. The outer cover23covers the inner cover22and is attached to the end of the side wall26in the +Z direction by welding, for example.

The inner cover22is provided with a vent27. The outer cover23is provided with a vent28. After the components are attached to the inside of the base21and the inner cover22and the outer cover23are attached to the base21, the air is removed from inside the housing11through the vents27and28. Furthermore, the housing11is filled with a gas different from air.

The gas filling the housing11is, for example, a low density gas having a density lower than air, an inert gas having low reactivity, or the like. For example, the housing11is filled with helium inside. The inside of the housing11may be filled with another fluid. The inside of the housing11may be maintained at vacuum, low pressure close to vacuum, or negative pressure lower than atmospheric pressure.

The vent28of the outer cover23is closed by a seal29. The seal29airtightly seals the vent28and prevents the fluid filling the housing11from leaking from the vent28.

The plurality of magnetic disks12are arranged orthogonally to the Z direction. The diameter of the magnetic disk12is, for example, about 3.5 inches. The HDD10according to the present embodiment includes, for example, 10 or more magnetic disks12. The diameter and the number of the magnetic disks12are not limited to this example.

Each of the plurality of magnetic disks12has, for example, at least one recording surface31. The recording surface31is provided on at least one of the upper surface and the lower surface of the magnetic disk12. In other words, each of the plurality of recording surfaces31is a surface of the magnetic disk12facing substantially the +Z direction or a surface of the magnetic disk12facing substantially the −Z direction. The recording surface31is a substantially flat surface orthogonal to the Z direction. The magnetic recording layer of the magnetic disk12is provided on the recording surface31.

The spindle motor13supports the plurality of magnetic disks12stacked at intervals in the Z direction. The spindle motor13rotates the plurality of magnetic disks12around an axis Ax1 of the spindle motor13. The axis Ax1 extends in the Z direction. The plurality of magnetic disks12is held by the hub of the spindle motor13with, for example, a clamp spring.

The HSA14is rotatably supported by a support shaft35. The support shaft35is provided away from the magnetic disk12in a direction orthogonal to the axis Ax1. The support shaft35extends, for example, in the substantially +Z direction from the bottom wall25of the housing11.

The HSA14can rotate about an axis Ax2. The axis Ax2 is an example of a rotation axis and is a virtual axis extending in the Z direction. The axis Ax2 is, for example, the center of rotation of the HSA14and coincides with the axis of the support shaft35.

Hereinafter, an axial direction, a radial direction, and a circumferential direction are defined for convenience. The axial direction is a direction along the axis Ax2. In the present embodiment, the axis Ax2 extends in the Z direction. Therefore, the axial direction includes the Z direction. The radial direction is a direction orthogonal to the axis Ax2, and includes a plurality of directions orthogonal to the axis Ax2. The circumferential direction is a rotational direction around the axis Ax2, and includes a clockwise direction around the axis Ax2 and a counterclockwise direction.

The HSA14includes a carriage41, a plurality of head gimbal assemblies (HGA)42, and a flexible printed circuit board (FPC)43. The carriage41includes an actuator block51, a plurality of arms52, and a frame53.

The actuator block51, the plurality of arms52, and the frame53are integrally formed of, for example, an aluminum alloy. The materials of the actuator block51, the arms52, and the frame53are not limited to this example.

The actuator block51is supported by the support shaft35via, for example, a bearing so as to be rotatable about the axis Ax2. The plurality of arms52protrude radially outward from the actuator block51. Therefore, the plurality of arms52is rotatable about the axis Ax2. The HSA14may be divided, and the arm52may protrude from each of the plurality of actuator blocks51.

The plurality of arms52is disposed at intervals in the axial direction. Each of the arms52has a plate shape to enter a gap between two adjacent magnetic disks12. The plurality of arms52extend substantially in parallel.

In the present embodiment, the carriage41includes 11 arms52. The number of the arms52is larger by one than the number of the magnetic disks12. The number of the arms52is not limited to this example.

The frame53protrudes from the actuator block51in a direction opposite to the direction in which the arm52protrudes. The frame53holds a voice coil of the VCM15. The VCM15includes the voice coil, a pair of yokes, and a magnet provided on the yoke.

FIG.2is an exemplary cross-sectional view illustrating the HGA42and the arm52of the first embodiment. As illustrated inFIG.2, in the present specification, a first direction D1 and a second direction D2 are defined. The first direction D1 is one of a plurality of directions included in the radial direction, and is a direction facing outward in the radial direction. Therefore, the first direction D1 is a direction orthogonal to the axis Ax2. The second direction D2 is a direction opposite to the first direction D1. The first direction D1 is also an example of a first creeping direction. The second direction D2 is also an example of a second creeping direction.

The plurality of arms52protrude from the actuator block51in the first direction D1. That is, the first direction D1 and the second direction D2 are longitudinal directions of the arm52. As the arm52rotates about the axis Ax2, the first direction D1 and the second direction D2 also rotate about the axis Ax2. The frame53protrudes from the actuator block51in the second direction D2.

Each of the plurality of arms52has two attachment surfaces52a. The two attachment surfaces52aare located at the end of the arm52in the first direction D1 and are flat substantially orthogonal to the axis Ax2. One of the attachment surfaces52afaces the +Z direction, and the other attachment surface52afaces the −Z direction. When the arm52is located between two adjacent magnetic disks12, the attachment surface52afaces the recording surface31of the magnetic disk12.

Each arm52is provided with a through hole55. The through hole55is a substantially circular hole penetrating the arm52in the axial direction. Thus, the through hole55opens to the two attachment surfaces52a.

The plurality of HGAs42is attached to the end of the corresponding arms52in the first direction D1, and extends from the arms52in the first direction D1. As a result, the plurality of HGAs42is arranged at intervals in the axial direction.

FIG.3is an exemplary perspective view illustrating the HGA42of the first embodiment in an exploded manner.FIG.4is an exemplary perspective view illustrating a part of the HGA42of the first embodiment. As illustrated inFIG.3, each of the plurality of HGAs42includes a base plate61, a load beam62, a flexure63, a magnetic head64, and two piezoelectric elements65. The magnetic head64may also be referred to as a slider. The piezoelectric element65may also be referred to as an actuator.

The base plate61and the load beam62are made of, for example, stainless steel. The base plate61and the load beam62may be made of other materials or may be made of materials different from each other.

As illustrated inFIG.2, the base plate61is attached to the attachment surface52aof the arm52. Specifically, the base plate61is attached to the arm52away from the axis Ax2 in the first direction D1.

The base plate61includes a plate71and a boss72. The plate71has a substantially rectangular plate shape. The plate71has an inner side surface71aand an outer side surface71b. The inner side surface71ais an example of a first surface and a first outer surface. The outer side surface71bis an example of a second outer surface. The boss72is an example of the protrusion.

The inner side surface71ais substantially flat and faces the attachment surface52aof the corresponding arm52. The inner side surface71ais supported by the attachment surface52a. The outer side surface71bis opposite the inner side surface71a. The outer side surface71bis substantially flat and faces the recording surface31of the corresponding magnetic disk12. The inner side surface71aand the outer side surface71bare arranged substantially orthogonally to the axis Ax2. Thus, the first direction D1 and the second direction D2 are directions along the inner side surface71aand along the outer side surface71b.

The boss72protrudes from the inner side surface71ato be inserted into the through hole55. The base plate61is provided with a through hole75axially penetrating the plate71and the boss72. The boss72is fixed to the inner surface of the arm52forming the through hole55by, for example, caulking. Thus, the base plate61is attached to the arm52.

The load beam62illustrated inFIG.3has a plate shape thinner than the plate71of the base plate61. The load beam62is attached to an end of the plate71in the first direction D1 and extends from the plate71approximately in the first direction D1.

The load beam62includes an attachment part81, an extending part82, a lift tab83, and a dimple84. The attachment part81is attached to the plate71by welding, for example. The extending part82extends from an end of the attachment part81in the first direction D1.

The extending part82has a substantially triangular plate shape tapered in the first direction D1. As illustrated inFIG.2, the extending part82extends obliquely with respect to the inner side surface71aof the plate71from the attachment part81toward the corresponding magnetic disk12. In other words, the extending part82extends from the plate71in a direction between the first direction D1 and a direction which the outer side surface71bof the plate71faces. That is, the load beam62is bent at the boundary85between the attachment part81and the extending part82. The load beam62is not limited to this example.

The extending part82has an inner side surface82aand an outer side surface82b. The inner side surface82ais an example of a third surface and a third outer surface. The outer side surface82bis an example of a second surface and a fourth outer surface. The inner side surface82aand the outer side surface82bare substantially flat and are opposite to each other.

The inner side surface82aand the outer side surface82bare inclined with respect to the inner side surface71aof the plate71so as to be closer to the magnetic disk12as is further away from the arm52. The inner side surface82afaces in a direction between the first direction D1 and the direction in which the inner side surface71aof the plate71faces. The outer side surface82bfaces in a direction between the second direction D2 and a direction in which the outer side surface71bof the plate71faces. The outer side surface82bfaces the recording surface31of the corresponding magnetic disk12.

The lift tab83is provided at an end of the extending part82in the first direction D1. As illustrated inFIG.3, the dimple84is located near the lift tab83. The dimple84is a substantially hemispherical protrusion protruding from the outer side surface82bof the extending part82.

As illustrated inFIG.4, the flexure63has an elongated belt shape, and extends substantially in the radial direction along the arm52, the base plate61, and the load beam62. The flexure63includes, for example, an FPC91and a backing layer92.

The FPC91of the flexure63includes, for example, an insulating base layer, a conductive layer stacked on the base layer, and an insulating cover layer covering the conductive layer. The conductive layer of the FPC91includes a plurality of sets of wiring and a plurality of terminals. The FPC91is not limited to this example. The backing layer92is, for example, a flexible plate made of stainless steel. The backing layer92is attached to the base layer of the FPC91with, for example, an adhesive.

The flexure63includes a gimbal95(elastic support). The gimbal95is provided at an end of the flexure63in the first direction D1. The gimbal95is attached to the load beam62and is displaceable relative to the load beam62. The gimbal95includes a part of the FPC91and a part of the backing layer92. In the gimbal95, the backing layer92is located between the FPC91and the load beam62.

FIG.5is an exemplary cross-sectional view illustrating a part of the HGA42of the first embodiment. As illustrated inFIG.5, the backing layer92of the flexure63is attached to the outer side surface82bof the extending part82at the plurality of joints96. At the joints96, the load beam62and the backing layer92of the flexure63are joined together by spot welding, for example.

As illustrated inFIG.1, an end of the flexure63in the second direction D2 is connected to one end of the FPC43, for example, on the actuator block51. The other end of the FPC43is connected to a connector provided on the bottom wall25.

As illustrated inFIG.4, the magnetic head64is mounted on the gimbal95. In other words, the magnetic head64is mounted on the flexure63away from the axis Ax2 in the first direction D1 with respect to the base plate61.

For example, the terminal of the FPC91is exposed in the gimbal95. An electrode of the magnetic head64is bonded to the terminal by, for example, soldering. Thus, the FPC91of the flexure63is electrically connected to the magnetic head64. For example, the bonding between the magnetic head64and the gimbal95may be reinforced with an adhesive. Further, the FPC43is electrically connected to the magnetic head64via the FPC91of the flexure63.

The magnetic heads64record and reproduce information on and from the corresponding recording surfaces31of the plurality of magnetic disks12. In other words, the magnetic heads64read and write information from and to the magnetic disks12.

Each magnetic head64is supported by the dimple84. As a result, the magnetic head64mounted on the gimbal95can rotate around the dimple84with respect to the load beam62.

The piezoelectric element65is mounted on the gimbal95. For example, the piezoelectric element65is bonded to a terminal provided on the FPC91of the gimbal95by soldering or with a conductive adhesive. Thus, the FPC91of the flexure63is electrically connected to the piezoelectric element65.

FIG.6is an exemplary plan view illustrating the HGA42of the first embodiment. As illustrated inFIG.6, at least a part of the piezoelectric element65is located between the base plate61and the magnetic head64in the first direction D1. The piezoelectric element65may be aligned with the magnetic head64in a width direction Dw along the inner side surface82aand orthogonal to the first direction D1. The plurality of joints96are located between the base plate61and the piezoelectric element65in the first direction. The position of the piezoelectric element65is not limited to this example.

The piezoelectric element65can expand and contract in the first direction D1 or the second direction D2 according to the applied voltage. Along with expansion and contraction of the two piezoelectric elements65, the magnetic head64mounted on the gimbal95rotates, for example, in a substantially circumferential direction (seek direction).

The VCM15illustrated inFIG.1rotates the carriage41about the axis Ax2. As the carriage41rotates, the HGA42attached to the arm52rotates. The carriage41rotates about the axis Ax2 to move the magnetic head64to a desired position along the recording surface31of the magnetic disk12.

The magnetic head64moves to the outermost periphery of the magnetic disk12by the rotation of the carriage41by the VCM15, and the ramp load mechanism16holds the magnetic head64at the unload position by supporting the lift tab83. At the unload position, the magnetic head64is separated from the magnetic disk12.

The PCB17is, for example, a rigid board such as a glass epoxy board, a multilayer board, or a build-up board. The PCB17is attached to the bottom wall25of the base21outside the housing11.

Various electronic components such as a relay connector connected to the FPC43, an interface (I/F) connector connected to the host computer, and a controller that controls the operation of the HDD10are mounted on the PCB17. The relay connector is electrically connected to the FPC43via a connector provided on the bottom wall25.

As illustrated inFIG.6, the HGA42further includes a damper100. The damper100is attached to the inner side surface82aof the extending part82. As illustrated inFIG.5, the damper100includes a first damper101and a second damper102overlaid on the first damper101.

The first damper101is attached to the inner side surface82aof the extending part82to attenuate vibration of the extending part82. The second damper102is attached to the first damper101to attenuate vibration of the first damper101and vibration of the extending part82via the first damper101.

As illustrated inFIG.5, the first damper101includes a first constrained layer105and a first viscoelastic material (VEM)106. The second damper102includes a second constrained layer107and a second viscoelastic material108.

The first constrained layer105and the second constrained layer107are, for example, plates made of resin or metal and disposed along the inner side surface82aof the extending part82. The material of the first constrained layer105may be different from or the same as the material of the second constrained layer107.

In the direction orthogonal to the inner side surface82a, the first constrained layer105is different in thickness from the second constrained layer107. The first constrained layer105and the second constrained layer107may have the same thickness.

The first viscoelastic material106and the second viscoelastic material108are made of, for example, a polymer material. Each of the first viscoelastic material106and the second viscoelastic material108has lower rigidity than either of the first constrained layer105and the second constrained layer107.

The first viscoelastic material106is made of a different material from the second viscoelastic material108. For example, the first viscoelastic material106has more excellent damping characteristics than the second viscoelastic material108at a relatively low temperature. On the other hand, the second viscoelastic material108has more excellent damping characteristics than the first viscoelastic material106at a relatively high temperature. The damping characteristics of the first viscoelastic material106and the second viscoelastic material108are not limited to this example.

A difference in viscosity between the first viscoelastic material106and the second viscoelastic material108differ at a predetermined, relatively low temperature and at a predetermined, relatively high temperature. The predetermined, relatively low temperature is an example of a first temperature. The predetermined, relatively high temperature is an example of a second temperature.

In the direction orthogonal to the inner side surface82a, the thickness of the first viscoelastic material106is different from the thickness of the second viscoelastic material108. The first viscoelastic material106and the second viscoelastic material108may be made of the same material and/or have the same thickness.

The first viscoelastic material106is interposed between the first constrained layer105and the inner side surface82aof the extending part82. The first viscoelastic material106adheres to the first constrained layer105and to the inner side surface82a.

The second viscoelastic material108is interposed between the first constrained layer105and the second constrained layer107. The second viscoelastic material108adheres to the first constrained layer105and to the second constrained layer107.

The first constrained layer105and the second viscoelastic material108are located between the first viscoelastic material106and the second constrained layer107. The second constrained layer107is more spaced apart from the load beam62than the first constrained layer105.

Vibration of the extending part82, if it occurs, is transmitted to the first constrained layer105through the first viscoelastic material106. The vibration of the first constrained layer105with respect to the extending part82causes the first viscoelastic material106to deform between the extending part82and the first constrained layer105and transform energy of the vibration into heat. In this manner, the first damper101attenuates the vibration of the extending part82.

The vibration of the extending part82is transmitted to the second constrained layer107through the first viscoelastic material106, the first constrained layer105, and the second viscoelastic material108. The vibration of the second constrained layer107with respect to the first constrained layer105causes the second viscoelastic material108to deform between the first constrained layer105and the second constrained layer107and transform energy of the vibration into heat. In this manner, the second damper102attenuates the vibration of the extending part82via the first damper101.

The first constrained layer105has a first attached surface105a. The first attached surface105ais substantially flat and faces the inner side surface82aof the extending part82. The first viscoelastic material106is attached to the first attached surface105a.

The second constrained layer107has a second attached surface107a. The second attached surface107ais substantially flat and faces the first constrained layer105. Further, the second attached surface107afaces the inner side surface82avia the first constrained layer105.

When viewed in a direction orthogonal to the inner side surface82a, the projection surface of the first constrained layer105substantially matches the first attached surface105a. The projection surface of the second constrained layer107substantially matches the second attached surface107a.

In the first embodiment, the second constrained layer107is smaller in size than the first constrained layer105. The second attached surface107ais thus smaller in size than the first attached surface105a. The sizes of the first constrained layer105and the second constrained layer107are not limited to this example.

When viewed in a direction orthogonal to the inner side surface82a, the projection surface of the first constrained layer105substantially matches the projection surface of the first viscoelastic material106. The projection surface of the second constrained layer107substantially matches the projection surface of the second viscoelastic material108.

The projection surfaces of the first constrained layer105, the first viscoelastic material106, the second constrained layer107, and the second viscoelastic material108have a substantially trapezoidal shape tapered in the first direction D1. The shapes of the first constrained layer105, the first viscoelastic material106, the second constrained layer107, and the second viscoelastic material108are not limited to this example.

As illustrated inFIG.6, the end105bof the first constrained layer105in the second direction D2 extends substantially linearly in the width direction Dw. The end107bof the second constrained layer107in the second direction D2 also extends substantially linearly in the width direction Dw.

The end107bof the second constrained layer107is located further away from the base plate61than the end105bof the first constrained layer105in the first direction D1. In other words, the end107bof the second constrained layer107is more separated from the axis Ax2 than the end105bof the first constrained layer105in the first direction D1. Further, the end108aof the second viscoelastic material108in the second direction D2 is located further away from the axis Ax2 in the first direction D1 than the end106aof the first viscoelastic material106in the second direction D2. As such, between the end107bof the second constrained layer107and the end105bof the first constrained layer105, the first constrained layer105is not covered with either the second constrained layer107or the second viscoelastic material108but exposed.

At the end100aof the damper100in the second direction D2, the number of the individual dampers (the first damper101and the second damper102) included in the damper100and overlapping the load beam62is smaller than the total number of the individual dampers included in the damper100. That is, the total number of the individual dampers (the first damper101and the second damper102) included in the damper100is two, and the number of dampers (the first damper101) overlapping the load beam62at the end100aof the damper100is one.

The end105bof the first constrained layer105and the end107bof the second constrained layer107may not extend linearly. In this case, a portion of the end107bof the second constrained layer107closest to the axis Ax2 is further away from the axis Ax2 in the first direction than a portion of the end105bof the first constrained layer105closest to the axis Ax2.

The second constrained layer107covers a closest one of the plurality of joints96relative to the piezoelectric element65via the first constrained layer105, the first viscoelastic material106, and the second viscoelastic material108. The damper100may further cover another one of the joints96.

In the HDD10described above, for example, a controller of the PCB17controls the VCM15via, for example, the FPC43, and controls the magnetic head64and the piezoelectric element65via the FPC43and the flexure63.

The controller of the PCB17rotates the carriage41by the VCM15to move the magnetic head64to a desired position on the recording surface31of the magnetic disk12. Furthermore, the controller of the PCB17adjusts the position of the magnetic head64by causing the two piezoelectric elements65to expand and contract.

By expanding and contracting, the piezoelectric elements65transmit the excitation force to the load beam62via the joint96. Due to the excitation force, the load beam62may vibrate in a twisted manner. The damper100, however, attenuates the vibration of the load beam62.

Hereinafter, a method of attaching the HGA42to the arm52, which is a part of the method of manufacturing the HDD10, will be exemplified with reference toFIG.7. The method of attaching the HGA42to the arm52is not limited to the following method, and other methods may be used.

FIG.7is an exemplary cross-sectional view illustrating the HGA42and the arm52in the manufacturing process of the first embodiment. As illustrated inFIG.7, when the HGA42is attached to the arm52, the base plate61is disposed on the attachment surface52aof the arm52.

The boss72of the base plate61is at least partially inserted into the through hole55of the arm52. At least an end of the boss72in the first direction D1 is hooked on the inner surface of the arm52. Furthermore, at least the end of the attachment surface52ain the first direction D1 supports the inner side surface71aof the plate71.

Each of the HGAs42is supported by a separate pin SP. The separate pin SP is, for example, a bar-shaped jig extending in the width direction Dw. The separate pin SP is in contact with, for example, the flexure63to support the HGA42.

The separate pins SP maintain an interval between the two HGAs42arranged on the two arms52. Thereby, the separate pins SP prevent the magnetic heads64of the two HGAs42arranged on the two arms52from interfering with each other.

Being supported by the separate pin SP, the HGA42may be inclined with respect to the attachment surface52aof the arm52. For example, the plate71of the base plate61is inclined with respect to the attachment surface52aof the arm52in such a manner that it is closer to another HGA42placed on the same arm52as is further away from the arm52.

Due to the inclination of one of the two HGAs42on the same arm52, for example, the two HGAs42become closest to each other in the vicinity of the boundary85between the attachment part81and the extending part82of the load beam62. In the present embodiment, the end100aof the damper100in the second direction D2 is located near the boundary85. Thus, the two HGAs42are closest to each other at the end100aof the damper100in the second direction D2. The two HGAs42may be closest to each other in another location.

At the end100aof the damper100in the second direction D2, the first constrained layer105is not covered with either of the second constrained layer107and the second viscoelastic material108but exposed. Because of this, the end100aof the damper100has a relatively small thickness in the direction orthogonal to the inner side surface82aof the extending part82.

The small thickness of the end100aof the damper100allows a relatively long distance between the dampers100of the two HGAs42to be set. This makes it possible to prevent the dampers100of the two HGAs42arranged on the same arm52from interfering with each other.

Next, for example, the plate71is pressed against the attachment surface52aof the arm52with a jig to insert the entire boss72into the through hole55. Further, by inserting another jig into the through hole75of the base plate61, the boss72is caulked to the inner surface of the arm52. As a result, the HGA42is attached to the arm52. After the HGA42is attached to the arm52, the separate pin SP is removed from the HDD10.

In the HDD10according to the first embodiment described above, the base plate61is attached to the arm52away from the axis Ax2 of the arm52in the first direction D1 orthogonal to the axis Ax2. The base plate61has the inner side surface71afacing the arm52. The load beam62is attached to the base plate61and has the outer side surface82band the inner side surface82a. The outer side surface82bfaces the magnetic disk12. The inner side surface82ais opposite the outer side surface82b, and is inclined with respect to the inner side surface71aso as to be closer to the magnetic disk12as is further away from the arm52. The damper100includes the first constrained layer105and the second constrained layer107and is attached to the inner side surface82aof the load beam62. The second constrained layer107is spaced further apart from the load beam62than the first constrained layer105. The end107bof the second constrained layer107and the end105bof the first constrained layer105are in the second direction D2 opposite to the first direction D1. The end107bof the second constrained layer107is located further away from the axis Ax2 than the end105bof the first constrained layer105in the first direction D1. To attach two HGAs42to the arm52, the HGAs42are disposed on both attachment surfaces52aof the arm52. At a position apart from the arm52in the first direction D1, the separate pins SP hold the load beams62of the two HGAs42in a manner that the load beams62approach each other. There may be a situation that the two HGAs42may become closest to each other at the end100aof the damper100in the second direction D2. However, at the end100aof the damper100in the second direction D2, the second constrained layer107does not cover the first constrained layer105, therefore, the damper100decreases in thickness at the end100a. Because of this, the HDD10can prevent the dampers100of the two HGAs42from interfering with each other.

The first viscoelastic material106is interposed between the first constrained layer105and the inner side surface82aof the load beam62. The second viscoelastic material108is interposed between the first constrained layer105and the second constrained layer107. The end106aof the first viscoelastic material106and the end108aof the second viscoelastic material108are in the second direction D2. The end108aof the second viscoelastic material108is located further away from the axis Ax2 than the end106aof the first viscoelastic material106in the first direction D1. At the end100aof the damper100in the second direction D2, the second viscoelastic material108does not cover the first constrained layer105, therefore, the damper100decreases in thickness at the end100a. This makes it possible to prevent the dampers100of the two HGAs42from interfering with each other in the HDD10.

The first constrained layer105has a first attached surface105afacing the inner side surface82a. The second constrained layer107has a second attached surface107afacing the first constrained layer105and being smaller in size than the first attached surface105a. That is, in the direction orthogonal to the inner side surface82a, the second constrained layer107has a smaller projected area than the first constrained layer105. Thereby, the HDD10enables downsizing of the damper100.

The piezoelectric element65is mounted on the flexure63. The expansion and contraction of the piezoelectric element65may cause the load beam62to vibrate via the flexure63. However, the damper100can attenuate the vibration of the load beam62. According to the HDD10, thus, the vibration caused by the piezoelectric element65can be attenuated by the damper100, and the dampers100of the two HGAs42can be prevented from interfering with each other.

The plurality of joints96is located between the base plate61and the piezoelectric element65. At the joints96, the load beam62and the flexure63are joined together. The second constrained layer107covers a closest one of the plurality of joints96relative to the piezoelectric element65via the first constrained layer105, the first viscoelastic material106, and the second viscoelastic material108. Vibration caused by the piezoelectric element65is transmitted from the flexure63to the load beam62through the joint96closest to the piezoelectric element65. Furthermore, the nodes of vibration caused by the piezoelectric element65are in the periphery of the joint96closest to the piezoelectric element65. In this regard, the two-layered damper100including the first constrained layer105, the first viscoelastic material106, the second constrained layer107, and the second viscoelastic material108covers the joint96closest to the piezoelectric element65, to be able to more effectively attenuate the vibration due to the piezoelectric element65.

The first viscoelastic material106is made of a different material from the second viscoelastic material108. As a result, the damper100can more efficiently attenuate vibration under different conditions, for example.

The difference in viscosity between the first viscoelastic material106and the second viscoelastic material108differs at a predetermined low temperature (first temperature) and at a predetermined high temperature (second temperature) different from the first temperature. Thus, the first viscoelastic material106and the second viscoelastic material108exhibit different characteristics, for example, at higher temperatures and at lower temperatures. As a result, the damper100can more efficiently attenuate the vibration in a wider range of temperature.

In the direction orthogonal to the inner side surface82a, the first viscoelastic material106and the second viscoelastic material108have mutually different thicknesses. The performance of the damper100can be affected by the thicknesses of the first viscoelastic material106and the second viscoelastic material108. In this regard, the HDD10enables appropriate setting of the performance of the damper100.

In the direction orthogonal to the inner side surface82a, the first constrained layer105and the second constrained layer107have mutually different thicknesses. The performance of the damper100can be affected by the thicknesses of the first constrained layer105and the second constrained layer107. In this regard, the HDD10enables appropriate setting of the performance of the damper100.

Second Embodiment

Hereinafter, a second embodiment will be described with reference toFIGS.8to10. In the following description of the embodiment, components having functions similar to those of the components already described are denoted by the same reference numerals as those of the components already described, and the description thereof may be omitted. In addition, the plurality of components denoted by the same reference numerals do not necessarily have all the functions and properties in common, and may have different functions and properties according to each embodiment.

FIG.8is an exemplary plan view illustrating the HGA42of a second embodiment. As illustrated inFIG.8, the HGA42of the second embodiment includes a damper200instead of the damper100. The damper200is substantially equal to the damper100except as described below.

FIG.9is an exemplary cross-sectional view illustrating a part of the HGA42of the second embodiment. As illustrated inFIG.9, in the second embodiment, the first constrained layer105is divided into a first member211and a second member212. That is, the first constrained layer105includes the first member211and the second member212.

The first member211and the second member212are, for example, plates made of resin or metal and disposed along the inner side surface82aof the extending part82. The material of the first member211may be different from or the same as the material of the second member212. The second member212is separated from the first member211in the first direction D1 via a gap.

In the direction orthogonal to the inner side surface82aof the extending part82, the thickness of the first member211is different from the thickness of the second member212. The thickness of the first member211and the thickness of the second member212may be the same.

In the second embodiment, the first viscoelastic material106is divided into a first intermediate material215and a second intermediate material216. That is, in the damper200, the first viscoelastic material106includes the first intermediate material215and the second intermediate material216.

The first intermediate material215and the second intermediate material216are viscoelastic materials (VEM). The first intermediate material215is interposed between the first member211and the inner side surface82aof the extending part82. The second intermediate material216is interposed between the second member212and the inner side surface82a. Therefore, the second intermediate material216is separated from the first intermediate material215in the first direction D1 via a gap.

The second damper102is attached to the second member212of the first damper101. That is, the second viscoelastic material108is interposed between the second member212and the second constrained layer107. The second viscoelastic material108is separated from the first member211and the first intermediate material215.

In the direction orthogonal to the inner side surface82aof the extending part82, the thickness of the first intermediate material215is different from the thickness of the second intermediate material216. The thickness of the first intermediate material215and the thickness of the second intermediate material216may be the same.

The damper200is divided into a single-layer damper221and a multilayer damper222by dividing the first constrained layer105and the first viscoelastic material106. In other words, the damper200includes the single-layer damper221and the multilayer damper222.

The single-layer damper221includes the first member211and the first intermediate material215. That is, the single-layer damper221includes a part of the first damper101but does not include the second damper102. Therefore, the first member211is exposed without being covered with either the second constrained layer107or the second viscoelastic material108.

The multilayer damper222includes the second member212, the second intermediate material216, the second constrained layer107, and the second viscoelastic material108. That is, the multilayer damper222includes a part of the first damper101and the second damper102. The multilayer damper222is separated from the single-layer damper221in the first direction D1.

When viewed in the direction orthogonal to the inner side surface82a, the projection surfaces of the second member212, the second intermediate material216, the second constrained layer107, and the second viscoelastic material108are substantially equal to each other and overlap each other in the direction orthogonal to the inner side surface82a. Therefore, the edge107cof the second constrained layer107, the edge108bof the second viscoelastic material108, the edge212aof the second member212, and the edge216aof the second intermediate material216overlap in the direction orthogonal to the inner side surface82a.

The edges107c,108b,212a, and216aof the second constrained layer107, the second viscoelastic material108, the second member212, and the second intermediate material216form the edge222aof the multilayer damper222that is substantially flat in a direction orthogonal to the inner side surface82a. The positions and shapes of the edges107c,108b,212a, and216amay be different from each other.

In the direction orthogonal to the inner side surface82a, the thickness of the first intermediate material215is larger than the thickness of the second intermediate material216. In the direction orthogonal to the inner side surface82a, the thickness of the multilayer damper222is larger than the thickness of the single-layer damper221. In other words, in the direction orthogonal to the inner side surface82a, the sum of the thicknesses of the second member212, the second intermediate material216, the second constrained layer107, and the second viscoelastic material108is larger than the sum of the thicknesses of the first member211and the first intermediate material215.

The end211aof the first member211in the second direction D2 forms the end105bof the first constrained layer105in the second direction D2. Therefore, the end107bof the second constrained layer107in the second direction D2 is separated from the axis Ax2 in the first direction D1 more than the end211aof the first member211in the second direction D2.

FIG.10is an exemplary cross-sectional view illustrating the HGA42and the arm52in the manufacturing process of the second embodiment. As illustrated inFIG.10, when the separate pin SP inclines the HGA42, the two HGAs42are closest to each other at the end200aof the damper200in the second direction D2.

The single-layer damper221is located at the end200aof the damper200in the second direction D2. Therefore, the thickness of the end200aof the damper200is relatively small in the direction orthogonal to the inner side surface82aof the extending part82. Since the thickness of the end200aof the damper200is small, the distance between the dampers200of the two HGAs42is set to be relatively large. Therefore, the two HGAs42arranged on the common arm52can be prevented from interfering with each other.

According to the HDD10of the second embodiment described above, the first constrained layer105includes the first member211and the second member212located apart from the first member211with a gap in the first direction D1. The first viscoelastic material106includes the first intermediate material215and the second intermediate material216. The first intermediate material215is interposed between the first member211and the inner side surface82a. The second intermediate material216is apart from the first intermediate material215with a gap in the first direction D1, and is interposed between the second member212and the inner side surface82a. The second viscoelastic material108is interposed between the second member212and the second constrained layer107and is apart from the first member211. The end211aof the first member211and the end107bof the second constrained layer107are in the second direction D2. The end107bof the second constrained layer107is further away from the axis Ax2 than the end211aof the first member211in the first direction D1. That is, the single-layer damper221including the first member211and the second intermediate material216and the multilayer damper222including the second member212, the second intermediate material216, the second constrained layer107, and the second viscoelastic material108are both attached to the inner side surface82awith spacing therebetween. This makes it possible to separately manufacture the single-layer damper221and the multilayer damper222d. As such, the damper200can be easily formed as compared with the second damper102attached to the first damper101, resulting in facilitating the manufacture of the HDD10.

In the direction orthogonal to the inner side surface82a, the first intermediate material215and the second intermediate material216have mutually different thicknesses. The single-layer damper221and the multilayer damper222can be affected by the thicknesses of the first intermediate material215and the second intermediate material216(viscoelastic materials) in terms of their performance. In this regard, the HDD10enables appropriate setting of the performance of the single-layer damper221and the multilayer damper222.

In the direction orthogonal to the inner side surface82a, the first intermediate material215is larger in thickness than the second intermediate material216. In the direction orthogonal to the inner side surface82a, the total thickness of the second member212, the second intermediate material216, the second constrained layer107, and the second viscoelastic material108is larger than the total thickness of the first member211and the first intermediate material215. As a result, the HDD10allows the single-layer damper221of a relatively large size, resulting in improvement in performance of the single-layer damper221. Furthermore, in the HDD10, the single-layer damper221has a smaller thickness than the multilayer damper222, which leads to preventing the interference between the dampers200of the two HGAs42.

The edge107cof the second constrained layer107and the edge212aof the second member212overlap each other in the direction orthogonal to the inner side surface82a. That is, the projection surface of the second constrained layer107and the projection surface of the second member212substantially coincide with each other in the direction orthogonal to the inner side surface82a. This makes it possible to easily form the multilayer damper222including the second member212, the second intermediate material216, the second constrained layer107, and the second viscoelastic material108by punching, for example. As such, the multilayer damper222can be easily formed, resulting in facilitating the manufacture of the HDD10.

In the above description, “prevent” is defined as, for example, preventing the occurrence of an event, an action, or an influence, or reducing the degree of the event, the action, or the influence. Furthermore, in the above description, the “restrict” is defined as, for example, preventing movement or rotation, or allowing movement or rotation within a predetermined range and preventing movement or rotation beyond the predetermined range.

While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel embodiments described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the inventions.