Hard Disk Drive Gimbal Design with High Torsional Frequency

Abstract

A trace gimbal is described herein. In some embodiments, the trace gimbal includes an outer strut including a forward outrigger at a distal end of the trace gimbal and an aft outrigger at a proximal end of the trace gimbal. The forward outrigger includes a distal forward outrigger and a proximal forward outrigger, and the aft outrigger includes a distal aft outrigger and a proximal aft outrigger. The trace gimbal further includes a middle strut that extends across the width of the trace gimbal and adjoins the proximal forward outrigger to the aft outrigger, and an inner strut that connects the middle strut to a slider tongue. The inner strut and the middle strut adjoin the outer gimbal strut to the slider tongue.

Description

[Technical field]

[0001] FIELD OF THE DISCLOSURE The present disclosure relates to the field of suspensions for hard disk drives. More particularly, the present disclosure relates to the field of gimbal assemblies for suspensions. [Background technology]

[0002] Disk storage devices use rotating disks to store information. Disk storage devices typically include a frame that provides mounting points and orientation for other components, and a spindle motor attached to the frame to rotate the disk. A head slider includes a read / write head for writing data to and reading data from the disk surface. The head slider is supported and properly oriented relative to the disk by a suspension that provides both the force and resilience required for proper head slider operation. As the disk in the storage device rotates under the head slider and head suspension, the air above the disk also rotates, creating an air bearing. The air bearing works with the aerodynamic design of the suspension to create a lift force. The lift force is opposed by the spring force of the suspension to position the head slider at a desired height and alignment above the disk, called the flying height.

[0003] A suspension for a disk drive includes a load beam and a flexure. The load beam typically includes a mounting region for mounting the suspension to an actuator of the disk drive, a rigid region, and a spring region between the mounting region and the rigid region. The spring region provides a spring force to counteract the aerodynamic lift force generated on the suspension during the drive operation described above. The flexure typically includes a gimbal region having a slider mounting surface to which a head slider is attached. The gimbal region is elastically movable relative to the rest of the flexure in response to the aerodynamic force generated by the air bearing. The gimbal region can move the head slider in pitch and roll directions to follow variations in the disk surface.

[0004] Disk drive manufacturers continue to develop smaller and higher storage capacity drives. The increased storage capacity is achieved in part by increasing the density of the information tracks on the disk (i.e., by using narrower and / or more closely spaced tracks). However, as track density increases, it becomes increasingly difficult for the motor and servo control systems to quickly and accurately position the read / write head over the desired track. In an attempt to remedy this situation, separate or secondary actuators have been provided, such as piezoelectric actuators, electrostatic actuators, electromagnetic actuators or fine tracking motors attached to the head suspension itself. These types of actuators are also known as microactuation devices and may be located on the base plate, load beam, or flexure.

[0005] In some of these attempts to improve tracking and head slider positioning control, actuators have been placed simultaneously on both the base plate and the flexure tongue. Typically, this type of suspension uses a voice coil and actuator located in the base plate area for large movements of the read / write head, while an actuator located on the flexure tongue is used for the fine movements required to position the read / write head over the track of the disk drive. Summary of the Invention

[0006] Described herein is a trace gimbal. According to some embodiments of the present disclosure, the trace gimbal includes an outer strut including a forward outrigger at a distal end of the trace gimbal and an aft outrigger at a proximal end of the trace gimbal. The forward outrigger includes a distal forward outrigger and a proximal forward outrigger, and the aft outrigger includes a distal aft outrigger and a proximal aft outrigger. The trace gimbal further includes a middle strut extending across the width of the trace gimbal and adjoining the proximal forward outrigger to the aft outrigger, and an inner strut connecting the middle strut to a slider tongue. The inner strut and the middle strut adjoin the outer gimbal strut to the slider tongue.

[0007] According to some embodiments of the present disclosure, the trace gimbal further comprises one or more micro-actuators attached to the slider tongue, the inner struts supporting the slider tongue.

[0008] According to some embodiments of the present disclosure, the proximal front outrigger includes a first cross-section and the distal front outrigger includes a second cross-section, the width of the second cross-section being approximately the same dimension as the first cross-section of the proximal front outrigger.

[0009] According to some embodiments of the present disclosure, the first and second cross sections of the front outrigger are between 0.05 mm (millimeters) and 0.10 mm. According to some embodiments of the present disclosure, the distal aft outrigger includes a first cross-section and the proximal aft outrigger includes a second cross-section that is larger than the first cross-section.

[0010] According to some embodiments of the present disclosure, the first cross section of the distal rear outrigger is between 0.10 mm and 0.20 mm. According to some embodiments of the present disclosure, the inner struts include a distal end and a proximal end, the distal end of the middle strut connects to the distal end of the inner strut and the proximal end of the inner strut connects to the slider tang.

[0011] According to some embodiments of the present disclosure, the inner struts generally extend from the distal end of the middle strut toward the proximal end of the trace gimbal to connect to the slider tang.

[0012] According to some embodiments of the present disclosure, the forward outriggers and the middle struts are generally formed in a C-shape or U-shape. According to some embodiments of the present disclosure, the cross-section of the middle strut is approximately the same as the first and second cross-sections of the forward outrigger.

[0013] A suspension with a trace gimbal according to some embodiments of the present disclosure is also provided. According to some embodiments of the present disclosure, the trace gimbal further comprises one or more micro-actuators attached to the slider tongue, the inner struts supporting the slider tongue.

[0014] According to some embodiments of the present disclosure, the proximal front outrigger includes a first cross-section and the distal front outrigger includes a second cross-section, the width of the second cross-section being approximately the same dimension as the first cross-section of the proximal front outrigger.

[0015] According to some embodiments of the present disclosure, the first and second cross sections of the front outrigger are between 0.01 mm and 0.10 mm. According to some embodiments of the present disclosure, the distal aft outrigger includes a first cross-section and the proximal aft outrigger includes a second cross-section that is larger than the first cross-section.

[0016] According to some embodiments of the present disclosure, the first cross section of the distal rear outrigger is between 0.01 mm and 0.10 mm. According to some embodiments of the present disclosure, the inner struts include a distal end and a proximal end, the distal end of the middle strut connects to the distal end of the inner strut and the proximal end of the inner strut connects to the slider tang.

[0017] According to some embodiments of the present disclosure, the inner struts generally extend from the distal end of the middle strut toward the proximal end of the trace gimbal to connect to the slider tang.

[0018] According to some embodiments of the present disclosure, the forward outriggers and the middle struts are generally formed in a C-shape or U-shape. According to some embodiments of the present disclosure, the cross-section of the middle strut is approximately the same as the first and second cross-sections of the forward outrigger.

[0019] While multiple embodiments are disclosed, still other embodiments of the present disclosure will become apparent to those skilled in the art from the following detailed description, which shows and describes illustrative embodiments of the present disclosure. Accordingly, the drawings and detailed description are to be regarded as illustrative in nature and not restrictive.

[0020] To illustrate how the above and other advantages and features of the present disclosure may be obtained, a more detailed description of the principles described above will be given by reference to specific examples illustrated in the accompanying drawings. These drawings are merely illustrative of exemplary aspects of the present disclosure and should not be construed as limiting its scope. The principles will be described and explained with additional specificity and detail using the following drawings: [Brief description of the drawings]

[0021] [Figure 1] FIG. 2 illustrates a gimbal assembly of a suspension according to some embodiments of the present disclosure. [Diagram 2] FIG. 13 illustrates roll stiffness and torsional frequency of a gimbal according to some embodiments of the present disclosure. [Figure 3A] FIG. 13 is a perspective view of an example mode shape of a first gimbal twist according to some embodiments of the present disclosure. [Figure 3B] FIG. 13 is a perspective view of an example mode shape of a second gimbal twist according to some embodiments of the present disclosure. [Figure 3C] FIG. 13 is a perspective view of an example mode shape of a third gimbal twist according to some embodiments of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] An improved trace gimbal is described herein. The improved trace gimbal according to some embodiments of the present disclosure is part of a suspension for a magnetic or optical disk drive unit. The disk drive unit includes a rotating magnetic or optical disk having a pattern of magnetic ones and zeros that constitute data stored on the disk drive. The disk is driven by a drive motor. The disk drive unit according to some embodiments includes a suspension having a load beam, a base plate, and a trace gimbal, with a head slider attached to the trace gimbal proximate to a distal end of the trace gimbal. The proximal end of the suspension or load beam is the end that is supported, i.e., the end closest to the base plate, which is swaged or otherwise attached to an actuator arm. The distal end of the suspension or load beam is the end opposite the proximal end, i.e., the distal end is a cantilever end.

[0023] The trace gimbal is coupled to a base plate, which is coupled to a voice coil motor. The voice coil motor is configured to move the suspension in an arc to position the head slider over the correct data track of the magnetic disk. The head slider is supported on a gimbal that allows the slider to pitch and roll to follow the appropriate data track on the rotating disk, and thus can accommodate such variations without degrading performance. The variations typically include disk vibrations, inertial events such as collisions, and irregularities in the disk surface.

[0024] In some embodiments, the trace gimbal described herein is part of a DSA (dual stage actuation), triple stage, or other type of actuated suspension. The suspension may include a base plate and a load beam. The load beam includes a trace gimbal. The trace gimbal may include an attached actuator and a gimbal assembly. The actuator is operable to directly act on the gimbal assembly of the suspension configured to include a read / write head slider.

[0025] In some embodiments, the trace gimbal may include one or more actuator joints configured to receive an actuator. The trace gimbal, according to some embodiments, includes two actuator joints located on opposite sides of the trace gimbal. Each actuator joint includes an actuator mounting shelf.

[0026] In some embodiments, each actuator spans a respective gap at the actuator joint. The actuators are secured to the slider tongue by adhesive. The adhesive may include conductive or non-conductive epoxy appropriately applied to each end of the actuator. Positive and negative electrical connections can be made from the actuators to the trace gimbal by a variety of techniques. An actuated actuator expands and contracts to move a read / write head attached to the distal end of the suspension, thereby changing the length of the gap between the attached ends.

[0027] In some embodiments, the suspension may be configured as a one-stage actuation suspension, a two-stage actuation device, a three-stage actuation device, or other configurations. In some embodiments, the three-stage actuation suspension includes actuators disposed on the mount plate area and the trace gimbal, respectively. Any modification of the actuators may be incorporated into the suspension of the embodiments disclosed herein. In other words, the suspension may include more or less components than those shown without departing from the scope of the present disclosure. However, the components shown are sufficient to disclose an exemplary embodiment for implementing the disclosed principles.

[0028] FIG. 1 illustrates a trace gimbal 100 according to some embodiments of the present disclosure. The trace gimbal 100 includes one or more microactuators 450 attached to a slider tongue 130. The trace gimbal 100 includes an outer gimbal strut. The outer gimbal strut includes a forward outrigger 110 at a distal end of the trace gimbal 100. In some embodiments, the forward outrigger includes a proximal forward outrigger 114 and a distal forward outrigger 112. In some embodiments, the distal forward outrigger 112 and the proximal forward outrigger 114 are defined by a bent or non-linear feature of the forward outrigger 110. In some embodiments, the distal forward outrigger 112 and the proximal forward outrigger 114 may be indistinguishable and adjacent in a linear feature where the two features are not physically separate.

[0029] In some embodiments, the proximal front outrigger 114 includes a first cross-section and the distal front outrigger 112 includes a second cross-section, the second cross-section width having a width that is approximately the same dimension as the first cross-section of the proximal front outrigger. In some embodiments, the first and second cross-sections of the front outrigger are between 0.01 mm and 0.10 mm.

[0030] In some embodiments, the outer struts also include an aft outrigger 140 at a proximal end of the trace gimbal 100. In some embodiments, the aft outrigger 140 includes a proximal aft outrigger 144 and a distal aft outrigger 142. In some embodiments, the length direction of the trace gimbal 100 is defined as the direction extending from the proximal end to the distal end of the trace gimbal 100.

[0031] In some embodiments, the distal aft outrigger 142 and the proximal aft outrigger 144 are defined by a bent or non-linear feature of the aft outrigger 140. In some embodiments, the aft outrigger 140 is a linear feature. In some embodiments, the distal aft outrigger 142 and the proximal aft outrigger 144 may be indistinguishable and adjacent in a linear feature where the two features are not physically separated.

[0032] In some embodiments, the distal aft outrigger 142 includes a first cross-section and the proximal aft outrigger 144 includes a second cross-section that is larger than the first cross-section. In some embodiments, the first cross-section of the distal aft outrigger is between 0.01 mm and 0.10 mm. In some embodiments, the first cross-section of the distal aft outrigger is approximately the same as the first and second cross-sections of the front outrigger.

[0033] In some embodiments, the trace gimbal 100 also includes a middle strut 120 that extends across the width of the trace gimbal 100 (in some embodiments, substantially perpendicular to the length of the trace gimbal 100) and connects the forward outrigger 110 to the aft outrigger 140. In other words, the forward outrigger 110 and the aft outrigger 140 are adjacent at the proximal end of the middle strut 120. In some embodiments, the forward outrigger 110 and the middle strut 120 are generally formed in a generally C-shape or U-shape. In some embodiments, the cross section of the middle strut 120 is between 0.01 mm and 0.10 mm. In some embodiments, the cross section of the middle strut 120 is approximately the same as the first and second cross sections of the forward outrigger.

[0034] In some embodiments, the trace gimbal 100 also includes an inner strut 150 that extends from the slider tongue 130 and connects the middle strut 120 to the slider tongue 130. The inner strut 150 (and the middle strut 120) support the slider tongue 130 on which the read / write head is assembled. In some embodiments, the inner strut 150 includes a distal end 152 and a proximal end 154. In some embodiments, the distal end of the middle strut 120 connects to the distal end 152 of the inner strut 150, and the proximal end 154 of the inner strut 150 connects to the slider tongue 130. In some embodiments, the inner strut 150 connects to the slider tongue 130 by generally extending from the distal end of the middle strut 120 towards the proximal end of the trace gimbal 100.

[0035] In some embodiments, the cross-sectional width of the central portion of the inner strut 150 is greater than the cross-sectional width of the proximal forward outrigger 114, the distal forward outrigger 112, and the middle strut 120. In some embodiments, the first and second cross-sections of the forward outrigger are between 0.01 mm and 0.10 mm. In some embodiments, the first cross-section of the distal rear outrigger is between 0.01 mm and 0.10 mm. In some embodiments, the cross-section of the middle strut 120 is between 0.01 mm and 0.10 mm. In some embodiments, the cross-sectional width of the central portion of the inner strut is between 0.10 mm and 0.25 mm.

[0036] Without being bound to a particular theory, gimbal twisting frequency may be related to the mass and stiffness of the gimbal configuration (e.g., outriggers, middle struts, and inner struts). A stiffer gimbal structure may generally provide a higher gimbal twisting frequency, but high stiffness is undesirable because it reduces the flexibility of the gimbal tongue to pitch and roll freely. A shorter and narrower forward outrigger according to some embodiments of the present disclosure may allow the gimbal twisting frequency to be increased in a section where there is more movement at the gimbal twisting frequency, while the roll stiffness may be maintained. The narrower width may lower the mass of the outriggers and increase the gimbal twisting frequency. The narrower width may also maintain the gimbal roll stiffness in an appropriate range. The middle struts connecting the outriggers may increase the stiffness of the gimbal, increase the gimbal twisting frequency, and maintain the gimbal roll stiffness.

[0037] As shown in Figure 2, gimbals according to some embodiments of the present disclosure exhibit improved gimbal twist frequencies: the first gimbal twist is 14.1 kHz (kilohertz) (a 1.5 kHz increase over the gimbal twist of the present gimbal configuration), the second gimbal twist is 17.0 kHz (a 1.5 kHz increase over the second gimbal twist of the present gimbal configuration), and the third gimbal twist is 28.6 kHz (a 4.3 kHz increase over the third gimbal twist of the present gimbal configuration).

[0038] 3A-3C show example mode shapes for first gimbal twist, second gimbal twist, and third gimbal twist. Although multiple embodiments have been disclosed, further embodiments within the scope of the present disclosure will become apparent to those skilled in the art from the detailed description set forth herein, which shows and describes exemplary embodiments. Accordingly, the drawings and detailed description should be considered as illustrative in nature and not restrictive. Features and modifications of the various embodiments have been discussed herein and shown in the drawings. Although multiple embodiments have been disclosed, further embodiments of the present disclosure will become apparent to those skilled in the art from the following detailed description, which shows and describes exemplary embodiments of the present disclosure. Accordingly, the drawings and detailed description should be considered as illustrative in nature and not restrictive.

Claims

1. A trace gimbal, an outer strut including a forward outrigger at a distal end of the tracing gimbal and an aft outrigger at a proximal end of the tracing gimbal, the forward outriggers including a distal forward outrigger and a proximal forward outrigger, the aft outriggers including a distal aft outrigger and a proximal aft outrigger, and a length direction of the tracing gimbal is defined as a direction extending from the proximal end to the distal end; an intermediate strut extending in a width direction of the trace gimbal and extending toward a slider tongue, the width direction being perpendicular to the length direction, the intermediate strut including a first end that adjoins the proximal forward outrigger to the aft outrigger; an inner strut connecting the intermediate strut to the slider tang such that a second end of the intermediate strut connects to the inner strut; the inner strut and the middle strut adjacent the outer strut to the slider tongue; A trace gimbal, wherein a cross-sectional width of a central portion of the inner strut is greater than a cross-sectional width of the proximal forward outrigger, the distal forward outrigger, and the middle strut.

2. The trace gimbal of claim 1 , comprising one or more microactuators attached to the slider tongue, the inner struts supporting the slider tongue.

3. 2. The tracing gimbal of claim 1, wherein the proximal forward outrigger includes a first cross-section and the distal forward outrigger includes a second cross-section, the second cross-section width having a width approximately the same dimension as the first cross-section of the proximal forward outrigger.

4. The tracing gimbal of claim 3 , wherein the first cross-section and the second cross-section of the front outrigger are between 0.01 millimeters and 0.10 millimeters.

5. The tracing gimbal of claim 1 , wherein the distal aft outrigger includes a first cross-section and the proximal aft outrigger includes a second cross-section that is larger than the first cross-section.

6. The tracing gimbal of claim 5 , wherein the first cross-section of the distal aft outrigger is between 0.01 millimeters and 0.10 millimeters.

7. The tracing gimbal of claim 1 , wherein the inner strut includes a distal end and a proximal end, the middle strut connects to the distal end of the inner strut, and the inner strut connects to the slider tang.

8. The trace gimbal of claim 7 , wherein the inner strut extends from the middle strut toward a proximal end of the trace gimbal to connect to the slider tang.

9. The tracing gimbal of claim 1 , wherein the forward outrigger and the middle strut are formed in a C-shape or a U-shape.

10. The tracing gimbal of claim 1 , wherein the cross section of the middle strut is the same as the first cross section and the second cross section of the forward outrigger.

11. A suspension including a trace gimbal, The trace gimbal an outer strut including a forward outrigger at a distal end of the tracing gimbal and an aft outrigger at a proximal end of the tracing gimbal, the forward outriggers including a distal forward outrigger and a proximal forward outrigger, the aft outriggers including a distal aft outrigger and a proximal aft outrigger, the direction extending from the proximal end to the distal end being defined as a length direction; an intermediate strut extending in a width direction perpendicular to the length direction and extending toward a slider tang, the intermediate strut including a first end that abuts the proximal forward outrigger to the aft outrigger; an inner strut connecting the intermediate strut to the slider tang such that a second end of the intermediate strut connects to the inner strut; the inner strut and the middle strut adjacent the outer strut to the slider tongue; A suspension wherein a cross-sectional width of a central portion of the inner strut is greater than cross-sectional widths of the proximal forward outrigger, the distal forward outrigger, and the middle strut.

12. The suspension of claim 11 comprising one or more micro-actuators attached to the slider tongue, the inner struts supporting the slider tongue.

13. 12. The suspension of claim 11, wherein the proximal front outrigger includes a first cross-section and the distal front outrigger includes a second cross-section, and wherein a width of the second cross-section width is the same dimension as the first cross-section of the proximal front outrigger.

14. The suspension of claim 13 , wherein the first and second cross sections of the front outrigger are between 0.01 millimeters and 0.10 millimeters.

15. The suspension of claim 11 , wherein the distal rear outrigger includes a first cross-section and the proximal rear outrigger includes a second cross-section that is larger than the first cross-section.

16. The suspension of claim 15, wherein the first cross-section of the distal rear outrigger is between 0.01 millimeters and 0.10 millimeters.

17. The suspension of claim 11 , wherein the inner strut includes a distal end and a proximal end, the middle strut connects to the distal end of the inner strut, and the proximal end of the inner strut connects to the slider tang.

18. The suspension of claim 17 , wherein the inner strut extends from the middle strut toward a proximal end of the trace gimbal to connect to the slider tang.

19. The suspension of claim 11 , wherein the forward outrigger and the middle strut are formed in a C-shape or a U-shape.

20. The suspension of claim 11 , wherein a cross-section of the middle strut is approximately the same as the first cross-section and the second cross-section of the front outrigger.

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