Patent ID: 12211528

DETAILED DESCRIPTION

In general, according to one embodiment, a disk device includes a magnetic disk, a magnetic head, a flexure, a piezoelectric element, a first bonding material, a second bonding material, and a protrusion. The magnetic head is configured to read and write information from and to the magnetic disk. The magnetic head is mounted on the flexure. The flexure includes a first outer surface, a first pad, and a second pad. The first pad is on the first outer surface. The second pad is on the first outer surface apart from the first pad in a first direction along the first outer surface. The piezoelectric element includes a second outer surface, a first electrode, and a second outer surface. The second outer surface faces the first outer surface. The first electrode is on the second outer surface. The second electrode is on the second outer surface apart from the first electrode in the first direction. The first bonding material, which is conductive, bonds the first pad and the first electrode. The second bonding material, which is conductive, bonds the second pad and the second electrode. The protrusion is provided on the flexure, is located at least partially between the first bonding material and the second bonding material, and protrudes from the first outer surface.

First Embodiment

Hereinafter, a first embodiment will be described with reference toFIGS.1to7. Note that, in the present specification, the components according to embodiments and descriptions of the components may be described in a plurality of expressions. The components and the description are examples, and are not limited by the expression of the present specification. The components may also be identified with names different from those in the present specification. 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 an exploded hard disk drive (HDD)10according to a first embodiment. 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.

The HDD10includes a housing11, a plurality of magnetic disks12, a spindle motor13, a plurality of magnetic heads14, an actuator assembly15, a voice coil motor (VCM)16, a ramp load mechanism17, a flexible printed wiring board (FPC)18, and a printed wiring board (PCB)19. The magnetic head14may also be referred to as a slider.

The housing11includes a base21, an inner cover22, and an outer cover23. The base21is a bottomed container and has a bottom wall25and a side wall26. The bottom wall25has a substantially rectangular (quadrangular) plate shape. The side wall26protrudes from an edge of the bottom wall25.

The inner cover22is attached to the end of the side wall26with, for example, screws. The outer cover23covers the inner cover22and is airtightly fixed to the end of the side wall26by welding, for example.

The inside of the housing11is sealed. The magnetic disks12, the spindle motor13, the magnetic heads14, the actuator assembly15, the VCM16, the ramp load mechanism17, and the FPC18are disposed inside the housing11.

The inner cover22is provided with a vent22a. The outer cover23is provided with a vent23a. After the components are attached to the inside of the base21and the inner cover22and the outer cover23are attached to the base21, the air inside the housing11is removed from the vents22aand23a. 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 that of air, an inert gas having low reactivity, and the like. For example, the housing11is filled with helium inside. Note that the inside of the housing11may be filled with another fluid. In addition, the inside of the housing11may be maintained at vacuum, low pressure close to vacuum, or negative pressure lower than atmospheric pressure.

The vent23aof the outer cover23is closed by a seal28. The seal28airtightly seals the vent23aand prevents the fluid filling the housing11from leaking from the vent23a.

The magnetic disk12is, for example, a disk-shaped recording medium having a magnetic recording layer provided on a recording surface12asuch as an upper surface and a lower surface. The diameter of the magnetic disk12in the example ofFIG.1is, for example, 3.5 inches, but is not limited to this example.

The spindle motor13supports and rotates the plurality of magnetic disks12stacked at intervals in the direction in which the recording surface12afaces. The plurality of magnetic disks12is held by the hub of the spindle motor13by, for example, a clamp spring.

The magnetic head14records and reproduces information on and from the recording layer of the magnetic disk12. In other words, the magnetic head14reads and writes information from and to the magnetic disk12. The magnetic head14is mounted on the actuator assembly15.

The actuator assembly15is rotatably supported by a support shaft31disposed apart from the magnetic disk12. The VCM16rotates and disposes the actuator assembly15at a desired position. The ramp load mechanism17holds the magnetic head14moved to the outermost periphery of the magnetic disk12at an unload position spaced apart from the magnetic disk12.

The actuator assembly15includes an actuator block35, a plurality of arms36, and a plurality of head suspension assemblies (suspensions)37. The suspension37may also be referred to as a head gimbal assembly (HGA).

The actuator block35is rotatably supported by the support shaft31via a bearing, for example. The plurality of arms36protrude from the actuator block35in a direction substantially orthogonal to the support shaft31. The actuator block35and the plurality of arms36are integrally formed.

The plurality of arms36is disposed at intervals in the direction in which the support shaft31extends. Each of the arms36has a plate shape to enter between the adjacent magnetic disks12. The arms36extend substantially in parallel.

A voice coil of the VCM16is provided on a protrusion protruding from the actuator block35to the opposite side of the arm36. The VCM16includes a pair of yokes, a voice coil disposed between the yokes, and a magnet provided on the yoke.

As described above, the VCM16rotates the actuator assembly15. In other words, the VCM16integrally rotates (moves) the actuator block35, the arm36, and the suspension37.

The suspension37is attached to a distal end of the corresponding arm36and protrudes from the arm36. As a result, the plurality of suspensions37is disposed at intervals in the direction in which the support shaft31extends.

FIG.2is an exemplary perspective view illustrating a part of the suspension37of the first embodiment. As illustrated in the drawings, 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 suspension37. The Y axis is provided along the length of the suspension37. The Z axis is provided along the thickness of the suspension37.

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 the arrow of the X axis and a −X direction that 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 the arrow of the Y axis and a −Y direction that 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 the arrow of the Z axis and a −Z direction that is an opposite direction of the arrow of the Z axis.

The suspension37extends from the arm36in the +Y direction. Note that the arm36also extends from the actuator block35in the +Y direction. The Y direction is a longitudinal direction of the arm36and the suspension37.

Each of the plurality of suspensions37includes a base plate41, a load beam42, and a flexure43. Further, the magnetic head14is disposed at a distal end37aof the suspension37. The distal end37ais the end of the suspension37in the +Y direction. Note that the end of suspension37in the −Y direction is attached to the arm36. In addition, in the present specification, the end refers to not only an end of the element but also a portion near the end.

The base plate41and the load beam42are made of, for example, stainless steel. Note that the materials of the base plate41and the load beam42are not limited to this example. The base plate41has a plate shape and is attached to the distal end of the arm36. The load beam42has a plate shape thinner than the base plate41. The load beam42is attached to the distal end of the base plate41and protrudes from the base plate41.

The flexure43has an elongated belt shape. Note that the shape of the flexure43is not limited to this example. The flexure43is a flexible multi-layer plate including an insulating layer and a conductive layer on which wiring is arranged.

The flexure43includes a gimbal (elastic support portion)45at an end in the +Y direction. The gimbal is displaceable and located above the load beam42. The gimbal45is provided at the distal end37aof the suspension37. The magnetic head14is mounted on the gimbal45of the flexure43.

The end of the flexure43in the −Y direction is connected to the FPC18on the actuator block35, for example. As a result, the FPC18is electrically connected to the magnetic head14via the wiring of the flexure43.

A pair of first microactuators (MAs)47and a pair of second microactuators (MAs)48are mounted on the suspension37. The first MAs47and the second MAs48are piezoelectric elements. The first MAs47and the second MAs48are, for example, bulk piezoelectric elements. Note that the first MAs47and the second MAs48may be bulk and multilayer or thin-film piezoelectric elements. The first MAs47and the second MAs48are not limited to this example.

Each of the pair of first MAs47connects, for example, the base plate41and the load beam42. The end of the first MAs47in the +Y direction is attached to the load beam42, and the end of the first MAs47in the −Y direction is attached to the base plate41. Note that the first MAs47are not limited to this example. The pair of first MAs47is disposed apart from each other in the X direction.

The first MAs47can expand and contract in the Y direction according to the applied voltage. As the pair of first MAs47individually expand and contract, a portion of the suspension37closer to the distal end37athan the first MAs47elastically bends in the width direction. As a result, the first MAs47moves the magnetic head14mounted on the distal end37aof the suspension37.

The pair of second MAs48is disposed near the distal end37aof the suspension37. For example, the second MAs48are mounted on the gimbal45. The pair of second MAs48is disposed apart from each other in the X direction.

The second MAs48can expand and contract in the Y direction according to the applied voltage. As the pair of second MAs48individually expand and contract, the distal end37aof the suspension37elastically bends in the X direction. As a result, the second MAs48moves the magnetic head14mounted on the distal end37aof the suspension37.

As described above, the HDD10of the present embodiment adjusts the position of the magnetic head14by a so-called triple stage actuator (TSA) method in which the magnetic head14is moved by the VCM16, the first MAs47, and the second MAs48.

The PCB19illustrated inFIG.1is, for example, a rigid board such as a glass epoxy board, a multilayer board, a build-up board, or the like. The PCB19is disposed outside the housing11and is attached to the outside of the bottom wall25of the base21.

Various electronic components such as a relay connector connected to the FPC18, an interface (I/F) connector connected to the host computer, and a controller that controls the operation of the HDD10are mounted on the PCB19. The relay connector is electrically connected to the FPC18via a connector provided on the bottom wall25.

The flexure43has an outer surface43a. The outer surface43ais an example of the first outer surface. The outer surface43ais approximately flat and faces substantially the +Z direction. Note that the outer surface43amay be provided with minute unevenness. When the magnetic head14is located on the magnetic disk12, the outer surface43afaces the recording surface12aof the magnetic disk12.

The magnetic head14is mounted on the outer surface43a. For example, a plurality of pads is provided on the outer surface43a. The electrodes of the magnetic heads14are connected to pads on the outer surface43aby, for example, solder. Furthermore, the magnetic head14is fixed to the outer surface43aby, for example, an adhesive.

The gimbal45of the flexure43has two MA mounts49. Each of the two second MAs48is attached to the outer surface43aof the flexure43on the corresponding one of the two MA mounts49.

FIG.3is an exemplary plan view illustrating a part of the suspension37of the first embodiment. As illustrated inFIG.3, each of the two MA mounts49includes a periphery50, a first connection51, and a second connection52. The periphery50includes a first band portion55, a second band portion56, a third band portion57, and a fourth band portion58.

The first band portion55is spaced apart from the corresponding second MA48in the +Y direction and extends substantially in the Y direction. The second band portion56extends from the end of the first band portion55in the −Y direction toward the outside of the flexure43in the X direction.

The third band portion57is spaced apart from the corresponding second MA48in the −Y direction. The fourth band portion58is apart from the corresponding second MA48in the substantially X direction and extends in the substantially Y direction along the second MA48. The fourth band portion58is connected to an end of the second band portion56in the X direction and an end of the third band portion57in the X direction. In other words, the fourth band portion58connects the second band portion56and the third band portion57.

The first band portion55, the second band portion56, the third band portion57, and the fourth band portion58are spaced apart from the corresponding second MA48and surround the second MA48from three sides. As such, the periphery50has a substantially C shape. In the direction orthogonal to the Z direction, the second MA48is located apart from the periphery50and surrounded by the periphery50.

The first connection51protrudes from the third band portion57in the +Y direction. The first connection51is spaced apart from the first band portion55, the second band portion56, and the fourth band portion58. A first pad61is placed in the first connection51on the outer surface43a.

The second connection52protrudes from the first band portion55in the −Y direction. The second connection52is spaced apart from the third band portion57and the fourth band portion58. In addition, the second connection52is spaced apart from the first connection51in the +Y direction. The +Y direction is a direction along the outer surface43a, and is an example of the first direction.

A second pad62is placed in the second connection52on the outer surface43a. That is, the second pad62is spaced apart from the first pad61in the +Y direction on the outer surface43a.

One end of the corresponding second MA48is joined to the first pad61with a first adhesive65. The first adhesive is an example of the first bonding material. The other end of the corresponding second MA48is joined to the second pad62with a second adhesive66. The second adhesive66is an example of the second bonding material.

In the present embodiment, the first adhesive65and the second adhesive66are conductive adhesives. For example, the first adhesive65and the second adhesive66are epoxy-based adhesives mixed with a conductive filler such as silver. Note that the first bonding material and the second bonding material may be other conductive bonding materials such as solder.

The first connection51and the second connection52protrude from the substantially C-shaped periphery50toward the inside of the periphery50. The flexure43is provided with a gap G separating the first connection51and the second connection52.

The gap G is a hole or a cutout penetrating the flexure43in the substantially Z direction. The gap G is in alignment with part of the corresponding second MA48in the substantially Z direction between the first connection51and the second connection52. The Z direction is an example of a direction orthogonal to the first outer surface.

Along with an expansion or contraction of the second MA48in the Y direction, the distance between the first connection51and the second connection52changes. For example, the distal end37aof the suspension37is elastically bent along with a decrease in the distance between the first connection51and the second connection52in one of the MA mounts49, and an increase in the distance between the first connection51and the second connection52in the other MA mount49.

FIG.4is an exemplary cross-sectional view illustrating a part of the suspension37of the first embodiment along line F4-F4ofFIG.3. As illustrated inFIG.4, the second MA48includes a piezoelectric body70, a first electrode71, and a second electrode72.

The piezoelectric body70has a substantially rectangular parallelepiped shape extending in the Y direction. The piezoelectric body70has a bottom surface70a, a first end surface70b, and a second end surface70c. The bottom surface70ais an example of the second outer surface.

The bottom surface70ais located at the end of the piezoelectric body70in the −Z direction. The bottom surface70ais substantially flat and faces the −Z direction. The bottom surface70afaces the outer surface43aof the flexure43through a gap.

The bottom surface70afaces the outer surface43aof the first connection51and faces the outer surface43aof the second connection52. The bottom surface70aand the outer surface43aare disposed substantially parallel to each other. Note that the bottom surface70amay be inclined with respect to the outer surface43a.

The first end surface70bis provided at the end of the piezoelectric body70in the −Y direction. The second end surface70cis opposite the first end surface70b, and is provided at the end of the piezoelectric body70in the +Y direction.

As illustrated inFIG.3, the piezoelectric body70further includes two side surfaces70d. The side surfaces70dare an example of both ends of the piezoelectric element. The two side surfaces70dare provided at both ends of the piezoelectric body70in the X direction.

The first electrode71inFIG.4is, for example, a positive electrode of the second MA48. The first electrode71is placed on the bottom surface70aand the first end surface70b. The first electrode71is spaced apart from the second end surface70c.

The second electrode72is, for example, a negative electrode of the second MA48. The second electrode72is placed on the bottom surface70a. The second electrode72is adjacent to the second end surface70cand apart from the first electrode71in the +Y direction.

At least a part of the first electrode71overlaps the first pad61in the Z direction. The first adhesive65works to bond the first pad61and the first electrode71together. In other words, the first adhesive65physically and electrically connects between the first pad61and the first electrode71.

At least a part of the second electrode72overlaps the second pad62in the Z direction. The second adhesive66bonds the second pad62and the second electrode72. In other words, the second adhesive66physically and electrically connects the second pad62and the second electrode72.

The flexure43includes a backing layer81, a base layer82, a conductive layer83, and a cover layer84. The backing layer81is an example of a metal plate. The base layer82is an example of a second insulating layer. The cover layer84is an example of a first insulating layer. The backing layer81, the base layer82, the conductive layer83, and the cover layer84are laminated in the Z direction.

The backing layer81is, for example, a metal plate made of metal such as stainless steel. The backing layer81has two surfaces81aand81b. The surface81ais an example of the third surface. The surface81asubstantially flat and faces the +Z direction. The surface81bis opposite the surface81a. The surface81bis substantially flat and faces the −Z direction. The surface81bis exposed to the outside and forms the surface of the flexure43opposite the outer surface43a.

The base layer82and the cover layer84are made of an insulator such as polyimide (PI). The material of the base layer82is the same as the material of the cover layer84. Note that the material of the base layer82and the material of the cover layer84may be different from each other.

The base layer82covers the surface81aof the backing layer81and is fixed to the surface81a. The base layer82may be joined to the surface81avia, for example, an adhesive layer, or may be directly attached to the surface81a.

The base layer82has two surfaces82aand82b. The surface82ais substantially flat and faces the +Z direction. The surface82bis opposite the surface82a. The surface82bis substantially flat and faces the −Z direction. The surface82bis fixed to the surface81aof the backing layer81.

The conductive layer83is disposed on the surface82aof the base layer82. The conductive layer83is made of a conductor such as copper. The conductive layer83is thinner than the backing layer81. Note that the thicknesses of the backing layer81and the conductive layer83are not limited to this example.

The conductive layer83includes, for example, a plurality of wiring patterns and pads. The conductive layer83has the first pad61and the second pad62. Further, the conductive layer83includes a pad connected to the magnetic head14, a pad connected to the FPC18, and a wiring pattern that connects the plurality of pads to each other. Note that the conductive layer83is not limited to this example.

The cover layer84covers the surface82aof the base layer82and at least a part of the conductive layer83, and is fixed to the base layer82and the conductive layer83. That is, the cover layer84covers at least a part of the conductive layer83and covers the base layer82at a position where the conductive layer83is not provided. The cover layer84may be joined to the surface82aby, for example, an adhesive layer, or may be directly attached to the surface82a.

In the flexure43, the base layer82is located between the backing layer81and the cover layer84. The conductive layer83is located between the base layer82and the cover layer84. Note that the flexure43may be a multilayer board having a plurality of insulating layers and a plurality of conductive layers instead of the base layer82.

The cover layer84has two surfaces84aand84b. The surface84ais exposed to the outside and forms a part of the outer surface43aof the flexure43. The surface84bis opposite the surface84a. The surface84bis fixed to the surface82aof the base layer82and the conductive layer83.

The cover layer84is provided with a first hole85and a second hole86. The first hole85and the second hole86penetrate the cover layer84in the substantially Z direction and open to the surfaces84aand84b, respectively.

The first hole85is located in the first connection51to expose at least a part of the first pad61to the outside of the flexure43. The surface of the first pad61exposed through the first hole85forms a part of the outer surface43aof the flexure43.

The first adhesive65bonds the first pad61and the first electrode71via the first hole85. The first adhesive65covers the first pad61exposed through the first hole85. That is, the first pad61is exposed to the outside of the flexure43through the first hole85, but may be covered with an element different from the flexure43such as the first adhesive65.

The second hole86is located in the second connection52to expose at least a part of the second pad62to the outside of the flexure43. The surface of the second pad62exposed through the second hole86forms a part of the outer surface43aof the flexure43. That is, the outer surface43aincludes the surface84aof the cover layer84, the surface of the first pad61exposed through the first hole85, and the surface of the second pad62exposed through the second hole86.

The second adhesive66bonds the second pad62and the second electrode72via the second hole86. The second adhesive66covers the second pad62exposed through the second hole86. That is, the second pad62is exposed to the outside of the flexure43through the second hole86. Alternatively, the second pad62may be covered with an element different from the flexure43such as the second adhesive66.

In the present embodiment, the thickness of the cover layer84is substantially constant. Of the cover layer84, thus, the part covering the conductive layer83and the part covering the base layer82can be different in position in the Z direction.

The surface84ahas a first region84aa, a second region84ab, and a third region84ac. The first region84aais an example of the first surface. The second region84abis an example of the second surface. The first region84aa, the second region84ab, and the third region84acare a part of the outer surface43aand are included in the outer surface43a.

The first region84aais located in a part covering the first pad61, of the cover layer84. Therefore, the first hole85opens to the first region84aa. The second region84abis provided in a part of the cover layer84that covers the second pad62. The second hole86thus opens to the second region84ab.

The third region84acis provided in a portion of the cover layer84covering the base layer82. Therefore, the third region84acis closer to the base layer82than the first region84aaand the second region84ab. On the other hand, each of the first region84aaand the second region84abis closer to the second MA48than the third region84ac.

Note that the thickness of the cover layer84may not be constant. For example, in the Z direction, the position of the first region84aa, the position of the second region84ab, and the position of the third region84acmay be substantially the same.

In the direction orthogonal to the Z direction, the backing layer81and the base layer82are approximately the same in terms of shape and size. Thus, the backing layer81overlaps the first connection51and the second connection52in the Z direction, thereby improving the rigidity of the first connection51and the second connection52. The surface81aof the backing layer81faces the first pad61and the second pad62via the base layer82.

The flexure43is provided with two protrusions90. The protrusions90may also be referred to as, for example, walls or stops. The two protrusions90include a first protrusion91and a second protrusion92. In other words, one of the two protrusions90is the first protrusion91, and the other of the two protrusions90is the second protrusion92. Hereinafter, the description common to the first protrusion91and the second protrusion92will be described as the description of the protrusion90.

The two protrusions90both protrude substantially in the +Z direction from the outer surface43aof the flexure43. The first protrusion91protrudes from the outer surface43ain the first connection51. The second protrusion92protrudes from the outer surface43ain the second connection52. The first protrusion91and the second protrusion92are thus juxtaposed to each other with a gap in the Y direction.

The two protrusions90are both located at least partially between the first adhesive65and the second adhesive66. The two protrusions90are also located between the first pad61and the second pad62in the Y direction (+Y direction).

Each of the two protrusions90has an end surface90a. The end surface90ais located at the end of the protrusion90in the +Z direction and faces substantially the +Z direction. The position of the end surface90ais substantially unchanged in the Z direction. In other words, the distance between the end surface90aand the first region84aaor the second region84abin the Z direction is substantially constant. Note that the end surface90ais not limited to this example, and may have unevenness or inclination.

The first protrusion91is located between the first electrode71and the second electrode72in the Y direction. The end surface90aof the first protrusion91faces the bottom surface70aof the piezoelectric body70. In the present embodiment, the end surface90aof the first protrusion91is in contact with the bottom surface70a. Note that the end surface90aof the first protrusion91may be spaced apart from the bottom surface70a.

In the Y direction, the second protrusion92is located between both ends of the second electrode72. The end surface90aof the second protrusion92thus faces the second electrode72. In other words, the end surface90aof the second protrusion92faces the bottom surface70aon which the second electrode72is mounted. In the present embodiment, the end surface90aof the second protrusion92is in contact with the second electrode72. Note that the end surface90aof the second protrusion92may be spaced apart from the second electrode72.

For example, the protrusion90protrudes from the third region84acof the outer surface43aof the flexure43. The protrusion90protrudes from the third region84acbeyond the first region84aaand the second region84ab. Because of this, the end surface90aof the protrusion90is closer to the bottom surface70aof the piezoelectric body70than the first region84aaand the second region84abof the cover layer84.

The end surface90ais a portion of the flexure43closest to the second MA48. Note that the flexure43may have a portion close to the second MA48as much as the end surface90a, or may have a portion closer to the second MA48than the end surface90a.

As illustrated inFIG.3, the two protrusions90extend linearly in the substantially X direction. The two protrusions90thus extend substantially in parallel. Note that the protrusions90may extend in other directions or may extend in a curved form.

In the X direction the two protrusions90are longer than the second MA48. Further, in the X direction the two protrusions90extend across the two side surfaces70dof the piezoelectric body70. The X direction is a direction along the outer surface43aand orthogonal to the Y direction (+Y direction), and is an example of the second direction. Note that the length of the protrusion90in the X direction is not limited to this example.

As illustrated inFIG.4, in the present embodiment, the protrusions90are provided on the base layer82and the cover layer84. Note that the protrusions90may be provided on one of the base layer82and the cover layer84.

Specifically, at the end of the first connection51in the +Y direction, a part of the base layer82and a part of the cover layer84are bent to protrude from the outer surface43ain the +Z direction. As a result, the part of the base layer82and the part of the cover layer84form the first protrusion91.

Further, at the end of the second connection52in the −Y direction, a part of the base layer82and a part of the cover layer84are bent to protrude from the outer surface43ain the +Z direction. As a result, the part of the base layer82and the part of the cover layer84form the second protrusion92.

The first adhesive65adheres to the first pad61, the first electrode71, and the first protrusion91. Thus, the first adhesive65allows a part of the base layer82and a part of the cover layer84included in the first protrusion91to be maintained in a protruding posture from the outer surface43a.

The second adhesive66adheres to the second pad62, the second electrode72, and the second protrusion92. Thus, the second adhesive66allows a part of the base layer82and a part of the cover layer84included in the second protrusion92to be maintained in a protruding posture from the outer surface43a.

Hereinafter, an example of a method of mounting the second MA48on the flexure43as a part of the method of manufacturing the suspension37will be described with reference toFIGS.4to6. Note that the method of mounting the second MA48is not limited to the following method, and other methods may be used.

FIG.5is an exemplary cross-sectional view illustrating the flexure43and a jig J of the first embodiment. First, a part of the flexure43is bent using the jig J to form the protrusion90. That is, a part of the base layer82and a part of the cover layer84are bent at the end of the first connection51in the +Y direction and the end of the second connection52in the −Y direction.FIG.5virtually illustrates a part of the base layer82and a part of the cover layer84before being bent by a two-dot chain line.

A part of the base layer82and a part of the cover layer84are elastically deformed by being bent. The jig J holds the bent parts of the base layer82and the cover layer84. As a result, the jig J prevents the part of the base layer82and the part of the cover layer84from being restored to the original forms.

FIG.6is an exemplary cross-sectional view illustrating the flexure43and the second MA48of the first embodiment. Next, the first adhesive65is applied to the first pad61, and the second adhesive66is applied to the second pad62. At this point, the first adhesive65and the second adhesive66are not cured and have fluidity. Note that the first adhesive65may be applied to the first electrode71. In addition, the second adhesive66may be applied to the second electrode72.

Next, the second MA48is placed on the flexure43by, for example, a mounter. The mounter moves the second MA48close to the flexure43until the second MA48abuts on the protrusion90. As the second MA48approaches the flexure43, the first adhesive65and the second adhesive66are pressed between the outer surface43aof the flexure43and the bottom surface70aof the piezoelectric body70.

The first adhesive65and second adhesive66are pressed and spread along the outer surface43aand the bottom surface70a. For example, the first adhesive65and the second adhesive66spread in the X direction and the Y direction.

The edge of the pressed first adhesive65approaches, for example, the second pad62, the second adhesive66, and the second electrode72. However, as illustrated inFIG.4, the first protrusion91blocks the first adhesive65. In other words, the first protrusion91adheres to the first adhesive65to restrict the first adhesive65from further approaching the second pad62, the second adhesive66, and the second electrode72.

The first protrusion91is located between the first electrode71and the second electrode72in the Y direction. Therefore, the first adhesive65attached to the first protrusion91is spaced apart from the second electrode72. Further, the first adhesive65is spaced apart from the second pad62and the second adhesive66.

In the Y direction, the second protrusion92is located between both ends of the second electrode72in the Y direction. Therefore, the second adhesive66attached to the second protrusion92is spaced apart from the first electrode71. Further, the second adhesive66is spaced apart from the first pad61and the first adhesive65.

As described above, the first protrusion91and the second protrusion92restrict the first adhesive65and the second adhesive66from approaching each other. However, the first adhesive65and the second adhesive66may flow beyond the first protrusion91and the second protrusion92. However, the first protrusion91and the second protrusion92can reduce the amount of the first adhesive65and the second adhesive66flowing out beyond the first protrusion91and the second protrusion92.

Next, the first adhesive65and the second adhesive66are cured. As a result, the first adhesive65keeps the first protrusion91in a posture protruding from the outer surface43a. Further, the second adhesive66keeps the second protrusion92in a posture protruding from the outer surface43a.

Next, the jig J is removed from the flexure43. This completes the mounting of the second MA48on the flexure43. Note that the jig J may position the second MA48in the Z direction.

In the above example, the protrusions90are formed by bending the base layer82and the cover layer84. Alternatively, the protrusions90may be formed by another method. For example, the protrusions90may be formed by etching at the time of manufacturing the flexure43.

FIG.7is an exemplary cross-sectional view illustrating a part of the suspension37according to a modification of the first embodiment. As illustrated inFIG.7, in the modification, the flexure43includes a base layer182instead of the base layer82, and includes a cover layer184instead of the cover layer84. The base layer182is equivalent to the base layer82except for the features as below. The cover layer184is equivalent to the cover layer84except for the features as below. The base layer182and the cover layer184do not include a bent part to form the protrusions90.

For example, in forming the base layer182, the base layer182is decreased in thickness by etching. This forms the surface82aon the base layer182. The rest of the base layer182with no decrease in thickness protrudes from the surface82ato form a protruding end182c.

The flexure43has protrusions190instead of the protrusions90. The protrusions190are equivalent to the protrusions90except for the features as below. A portion of the cover layer184covering the protruding end182cprotrudes from a portion of the cover layer184covering the surface82ain the +Z direction. As a result, a portion of the cover layer184covering the protruding end182chas a stepwise form, forming the protrusion190.

In addition, in forming the cover layer184, the cover layer184is partially decreased in thickness by etching. This forms the surface84aon the cover layer184. The rest of the cover layer184with no decrease in thickness protrudes from the surface84ato form a protruding end184c. That is, the protruding end184cprotrudes from the outer surface43aof the flexure43. The protruding end184cthus has a stepwise form to form the protrusion190.

In the HDD10according to the first embodiment described above, the first conductive adhesive65bonds the first pad61and the first electrode71. The second conductive adhesive66bonds the second pad62and the second electrode72. The flexure43is provided with the protrusions90. The protrusions90are located at least partially between the first adhesive65and the second adhesive66, and protrude from the outer surface43a. For example, in mounting the second MA48on the flexure43, the first adhesive65and the second adhesive66are pressed between the second MA48and the flexure43and spread along the outer surface43aand the bottom surface70a. The protrusions90can restrict the first adhesive65and the second adhesive66from approaching each other beyond the protrusions90by blocking at least one of the first adhesive65and the second adhesive66spreading along the outer surface43aand the bottom surface70a. As a result, the HDD10can restrain the first adhesive65and the second adhesive66from spreading in an undesirable direction, leading to avoiding the first electrode71and the second electrode72from short-circuiting due to the first adhesive65and second adhesive66. Thereby, the HDD10can provide stable electrical characteristics.

The cover layer84is provided with the first hole85for exposing the first pad61and the second hole86for exposing the second pad62. The cover layer84has the first region84aato which the first hole85is open, and the second region84abto which the second hole86is open. The first region84aaand the second region84abare included in the outer surface43a. A part of the cover layer84including the first region84aaand the second region84abcovers a part of the conductive layer83including the first pad61and the second pad62. Because of this, the first region84aaand the second region84abare closer to the bottom surface70athan a part of the cover layer84, the part not covering the conductive layer83. The protrusions90each have an end surface90afacing the bottom surface70a. The end surface90ais closer to the bottom surface70athan the first region84aaand the second region84ab. That is, the protrusions90protrude from the outer surface43ahigher than the first region84aaand the second region84ab. As a result, the protrusions90can restrict the first adhesive65and the second adhesive66from approaching each other beyond the protrusions90by blocking at least one of the first adhesive65and the second adhesive66spreading along the outer surface43aand the bottom surface70a.

The protrusions90include the first protrusion91. The first protrusion91is located between the first electrode71and the second electrode72in the +Y direction and protrudes from the outer surface43a. As a result, the first protrusion91can restrict the first adhesive65adhering to the first electrode71and the second adhesive66adhering to the second electrode72from approaching each other beyond the first protrusions91.

The protrusions90include the second protrusion92. The second protrusion92is located between the first pad61and the second pad62in the +Y direction, and protrudes from the outer surface43a. As a result, the second protrusion92can restrict the first adhesive65adhering to the first pad61and the second adhesive66adhering to the second pad62from approaching each other beyond the second protrusion92.

The end surfaces90aare closest to the second MA48in the flexure43. As a result, the protrusions90can restrict the first adhesive65and the second adhesive66from approaching each other beyond the protrusions90by blocking at least one of the first adhesive65and the second adhesive66spreading along the flexure43.

The protrusions90are provided on at least one of the cover layer84and the base layer82. This eliminates the necessity for the HDD10to add members and components to form the protrusions90, avoiding an increase in cost.

In the Z direction orthogonal to the outer surface43a, a distance between the first region84aaand the end surface90ais constant. In other words, the protrusion90has a constant height. As a result, the protrusion90can restrict the first adhesive65and the second adhesive66from approaching each other beyond the protrusion90.

In the X direction along the outer surface43aand orthogonal to the +Y direction, the protrusion90is longer than the second MA48and extends across both side surfaces70dof the second MA48. The protrusion90can restrict the first adhesive65and the second adhesive66from approaching each other beyond the protrusion90by blocking at least one of the first adhesive65and the second adhesive66spreading along the bottom surface70a.

The protrusion90is formed of, for example, a part of the elastically deformed flexure43. At least one of the first adhesive65and the second adhesive66adheres to the protrusion90. Thereby, at least one of the first adhesive65and the second adhesive66allows the protrusion90to be maintained in shape.

The flexure43includes the first connection51and the second connection52. The first connection51is provided with the first pad61. The second connection52is spaced apart from the first connection51in the +Y direction, and is provided with the second pad62. The first connection51and the second connection52are separated from each other with a gap G. The second MA48is located to cover the gap G in the Z direction orthogonal to the outer surface43a. Thereby, of the flexure43, the part including the first connection51can swing with respect to the part including the second connection52along with an expansion or contraction of the second MA48in the −Y direction.

Second Embodiment

Hereinafter, a second embodiment will be described with reference toFIG.8. Note that, in the following description of the plurality of embodiments, 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 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 cross-sectional view illustrating a part of the suspension37according to a second embodiment. In the second embodiment, the suspension37includes a flexure243instead of the flexure43. The flexure243is equivalent to the flexure43except for the features as below.

The flexure243includes a base layer282instead of the base layer82, and includes a cover layer284instead of the cover layer84. The base layer282is equivalent to the base layer82except for the features as below. The cover layer284is equivalent to the cover layer84except for the features as below. The base layer282and the cover layer284do not include a bent part to form the protrusions90.

The flexure243further includes an interlayer281in addition to the backing layer81, the base layer282, the conductive layer83, and the cover layer284. The interlayer281is, for example, an insulating layer made of an insulator such as PI. Note that the interlayer281may be made of a conductor.

The interlayer281is located between the backing layer81and the cover layer284in the Z direction. In the present embodiment, the interlayer281is located between the base layer282and the cover layer284. Note that the interlayer281is not limited to this example, and may be located between the backing layer81and the base layer282, for example. The thickness of the interlayer281is larger than the thickness of the conductive layer83.

The interlayer281is located at least partially between the first adhesive65and the second adhesive66in the Y direction (+Y direction). For example, a part of the interlayer281is located at the end of the first connection51in the +Y direction. In addition, the other part of the interlayer281is located at the end of the second connection52in the −Y direction.

The flexure243has two protrusions290instead of the two protrusions90. The protrusions290are equivalent to the protrusions90except for the features as below. A part, of the cover layer284, covering the interlayer281protrudes in a stepwise form from the rest. As a result, the part covering the interlayer281protrudes from the outer surface43aof the flexure243to form the protrusions290. In other words, the protrusions290include the overlapping part of the cover layer284with the interlayer281in the Z direction.

In the HDD10of the second embodiment described above, the flexure243further includes the interlayer281. The interlayer281is located between the backing layer81and the cover layer284in the Z direction orthogonal to the outer surface43a, and between the first adhesive65and the second adhesive66in the +Y direction. The protrusions290include a part of the cover layer284, the part overlapping the interlayer281in the Z direction. That is, the overlapping part of the cover layer284with the interlayer281protrudes from the rest by the thickness of the interlayer281to form the protrusions290. Thereby, forming the protrusions290in the HDD10can be facilitated.

For example, in the case of the interlayer281being a conductor, the interlayer281may cause short circuit or noise. However, the interlayer281of the present embodiment is an insulating layer. As a result, the HDD10can restrain the interlayer281from electrically affecting the flexure243as compared with the interlayer281being a conductor.

Third Embodiment

Hereinafter, a third embodiment will be described with reference toFIG.9.FIG.9is an exemplary cross-sectional view illustrating a part of the suspension37according to a third embodiment. In the third embodiment, the flexure43has a backing layer381instead of the backing layer81, a base layer382instead of the base layer82, and a cover layer384instead of the cover layer84. The backing layer381is equivalent to the backing layer81except for the features as below.

The base layer382is equivalent to the base layer82except for the features as below. The cover layer384is equivalent to the cover layer84except for the features as below. The base layer382and the cover layer384do not include a bent part to form the protrusions90.

The backing layer381further includes two inner protrusions381c. The two inner protrusions381care both located at least partially between the first adhesive65and the second adhesive66in the Y direction (+Y direction), and protrude from the surface81aof the backing layer381toward the second MA48.

The inner protrusions381care formed of, for example, a part of the bent backing layer381. Note that the inner protrusion381cis not limited to this example, and may be formed by, for example, etching, press molding, cutting, or another method.

The flexure43has two protrusions390instead of the two protrusions90. The protrusions390are equivalent to the protrusions90except for the features as below. A part, of the cover layer384, covering the inner protrusions381cprotrudes in a stepwise form from the rest. As a result, the part covering the inner protrusions381cprotrudes from the outer surface43aof the flexure43to form the protrusions390. In other words, the protrusions390include a part of the cover layer384, the part overlapping the inner protrusions381cin the Z direction.

In the HDD10of the third embodiment described above, the backing layer381has the front surface81aand the inner protrusions381c. The surface81afaces the first pad61and the second pad62via the base layer382. The inner protrusions381care located at least partially between the first adhesive65and the second adhesive66in the +Y direction, and protrude from the surface81atoward the second MA48. The protrusions390include a part of the cover layer384, the part overlapping the inner protrusions381cin the Z direction. That is, the overlapping part of the cover layer384with the inner protrusions381cprotrudes from the rest by the height of the inner protrusions381cto form the protrusions390. This can facilitate the formation of the protrusions390in the HDD10. This further eliminates the necessity for the HDD10to add members and components to form the protrusions390, thereby avoiding an increase in cost.

Fourth Embodiment

Hereinafter, a fourth embodiment will be described with reference toFIG.10.FIG.10is an exemplary cross-sectional view illustrating a part of the suspension37according to a fourth embodiment. In the fourth embodiment, the suspension37includes a flexure443instead of the flexure43. The flexure443is equivalent to the flexure43except for the features as below.

The flexure443includes a base layer482instead of the base layer82, and includes a cover layer484instead of the cover layer84. The base layer482is equivalent to the base layer82except for the features as below. The cover layer484is equivalent to the cover layer84except for the features as below. The base layer482and the cover layer484do not include a bent part to form the protrusions90.

The flexure443further includes a protruding layer481in addition to the backing layer81, the base layer482, the conductive layer83, and the cover layer484. The protruding layer481is an example of a third insulating layer. The protruding layer481is, for example, an insulating layer made of an insulator such as PI. The protruding layer481is provided on the surface84aof the cover layer484. In other words, the protruding layer481covers the outer surface43a.

The protruding layer481is located at least partially between the first adhesive65and the second adhesive66in the Y direction (+Y direction). For example, a part of the protruding layer481is located at the end of the first connection51in the +Y direction. In addition, the other part of the protruding layer481is located at the end of the second connection52in the −Y direction.

The flexure443has two protrusions490instead of the two protrusions90. The protrusions490are equivalent to the protrusions90except for the features as below. The protruding layer481protrudes from the outer surface43ato form the protrusions490. In other words, the protrusions490include the protruding layer481.

In the HDD10according to the fourth embodiment described above, the protrusions490include the protruding layer481covering the outer surface43a. That is, the protrusions490are formed by laminating the protruding layer481on the outer surface43a. Thereby, the protrusions490can be easily formed in the HDD10. Further, the HDD10allows easy adjustment of the height of the protrusions490.

The protruding layer481may be made of an insulating adhesive. For example, at the time of mounting the second MA48on the flexure43, the conductive first adhesive65and second adhesive66are applied to the first pad61and the second pad62, and the protruding layer481serving as an insulating adhesive is applied to the outer surface43a.

The protruding layer481can block the first adhesive65and the second adhesive66spreading along the outer surface43aand the bottom surface70awhile being pressed between the flexure443and the second MA48. The protruding layer481is attached to the second MA48to be able to fix the second MA48to the flexure443.

FIG.11is an exemplary plan view illustrating a part of the suspension37according to a modification of the fourth embodiment. In the modification ofFIG.11, the two protrusions490include a first protrusion491and a second protrusion492instead of the first protrusion91and the second protrusion92. The first protrusion491is equivalent to the first protrusion91except for the features as below. The second protrusion492is equivalent to the second protrusion92except for the features as below.

The first protrusion491is closer to the first pad61than to the second pad62. In other words, the distance between the first protrusion491and the first pad61is shorter than the distance between the first protrusion491and the second pad62.

The first protrusion491is bent in such a manner to be recessed toward the second pad62. In other words, the first protrusion491extends in a curved form to surround the first pad61. The first protrusion491has two side surfaces491aand491b.

In the direction intersecting the Z axis, the side surface491afaces the first pad61. The side surface491ais a curved surface which is recessed toward the second pad62. The side surface491bis opposite the side surface491a. The side surface491bis a curved surface projecting toward the second pad62. Note that the side surface491bmay extend linearly.

The first protrusion491and the second protrusion492are substantially mirror-symmetrical to each other across the gap G. That is, the second protrusion492is closer to the second pad62than to the first pad61. The second protrusion492is bent in such a manner as to be recessed toward the first pad61.

According to the HDD10of the modification ofFIG.11described above, the first protrusion491is closer to the first pad61than to the second pad62. The first protrusion491is bent in such a manner as to be recessed toward the second pad62. In other words, the first protrusion491extends to approximately surround the first pad61. As a result, the first protrusion491can effectively block the first adhesive65spreading along the outer surface43aand the bottom surface70a.

FIG.12is an exemplary plan view illustrating a part of the suspension37according to another modification of the fourth embodiment. In the modification ofFIG.12, the protrusion490includes a first protrusion495and a second protrusion496instead of the first protrusion91and the second protrusion92. The first protrusion495is equivalent to the first protrusion91except for the features as below. The second protrusion496is equivalent to the second protrusion92except for the features as below.

The first protrusion495is closer to the first pad61than to the second pad62. The first protrusion495has a side surface495a. In the direction intersecting the Z axis, the side surface495afaces the first pad61. The side surface495ais tapered toward the first pad61.

The first protrusion495and the second protrusion496are substantially mirror-symmetrical to each other across the gap G. That is, the second protrusion496is closer to the second pad62than to the first pad61. The second protrusion496has a side surface496athat tapers toward the second pad62.

According to the HDD10of the modification ofFIG.12, the first protrusion495is tapered toward the first pad61. As a result, the first protrusion495can restrict the first adhesive65from spreading along the outer surface43aand the bottom surface70atoward the second pad62.

In the above description, the words “prevent” and “restrain” is defined as, for example, preventing occurrence of an event, an action, or an influence, or reducing the degree of an event, an action, or an influence if it occurs. In addition, in the above description, the word “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.