KR100630743B1 - Yolk assembly with magnetic proximity latch and optional magnetic contact latch for contact start/stop hard disk drive, voice coil motor assembly having the same, and method of operating voice coil motor assembly - Google Patents

Abstract

The present invention provides a yoke assembly of a CSS hard disk drive having upper and lower proximal latch magnets and a voice coil motor assembly having the same. The yoke assembly includes a voice coil bias steel attached to the voice coil. Magnetic proximity latches are formed by attractive forces acting on the voice coil bias steel from the upper and lower proximity latch magnets. The present invention may include a magnetically weakened contact latch together with a magnetic proximity latch. In addition, the present invention provides a method of operating a voice coil motor assembly having at least a magnetic proximity latch. The crash stop, which is a combination of a magnetic proximity latch and a magnetically weakened contact latch according to the present invention, requires a significantly smaller initial release force than conventional crash stops, and satisfies rotational shock performance requirements.

Description

Yoke assembly of a contact start / stop hard disk drive having a magnetic proximity latch and an optional magnetic contact latch and a voice coil motor assembly and a method of operating the voice coil motor assembly with the same start / stop hard disk drive, voice coil motor assembly having the same, and method of operating voice coil motor assembly}

1A shows a voice coil interacting with a crash stop in a conventional CSS hard disk drive;

1B shows a voice coil contacting a magnetic proximity latch and an impact repelling member away from bias steel in a CSS hard disk drive according to the present invention;

1C shows the voice coil of FIG. 1B constrained by a magnetic proximity latch and in contact with the crash stop;

FIG. 1D shows the voice coil of FIGS. 1B and 1C positioned between the impact repelling member and the crash stop to begin to restrain the magnetic proximity latch;

FIG. 2A shows the head gimbal assembly of the actuator assembly located near the outer diameter of the disk, based on the condition shown in FIG. 1B;

FIG. 2B shows the head gimbal assembly of the actuator assembly positioned near the inner diameter of the disk, based on the condition shown in FIG. 1C;

FIG. 2C shows the head gimbal assembly of the actuator assembly located between the inner and outer diameters of the disk, based on the condition shown in FIG. 1D;

FIG. 2D summarizes the mechanical relationships related to the operation of the CSS hard disk drive according to the present invention partially shown in FIGS. 2A to 2C;

3A is a front perspective view of a yoke assembly of a CSS hard disk drive according to the present invention;

3B is a rear perspective view of the yoke assembly of the prior art;

3C is a rear perspective view of the yoke assembly according to the present invention;

4A shows a typical initial release force pattern in a prior art CSS hard disk drive;

4B shows a first initial release force pattern in a CSS hard disk drive employing only a magnetic proximity latch in accordance with the present invention as a crash stop;

4C shows a second initial release force pattern in a CSS hard disk drive employing a magnetic proximity latch and a magnetically weakened contact latch according to the present invention as a crash stop;

5 shows an actuator assembly according to the present invention comprising one or more actuator arms each having at least one head gimbal assembly;

6 is an exploded perspective view of the components used to assemble a CSS hard disk drive employing a voice coil motor assembly including various embodiments according to the present invention as a crash stop;

7 schematically illustrates the electrical operation of a typical CSS hard disk drive employing the present invention;

8a shows the actuator assembly according to the invention coupled to a disc bottom plate with a lower yoke mounting coupling;

8B shows a prior art OD (outer diameter) hard disk drive including a ramp in which the head gimbal assembly is parked;

9A shows in detail the program steps of a servo controller program system residing in the servo memory shown in FIG. 7 showing a method of operating a voice coil motor assembly according to the invention;

FIG. 9B details the unparking step of FIG. 9A using the first initial release force pattern as shown in FIG. 4B;

FIG. 9C shows in detail the de-parking step of FIG. 9A using the second initial release force pattern as shown in FIG. 4C.

<Explanation of symbols for the main parts of the drawings>

6 ... magnetic proximity latch 8 ... yoke assembly

10 ... CSS hard disk drive 12 ... base plate

14 ... Voice Coil 16 ... Actuator Pivot

18.Voice coil motor assembly 20 ... Upper yoke plate

22 Lower yoke plate 24 Upper voice coil retainer

26.Lower voice coil fixed magnet 28 ... York mounting coupling

30 ... yoke crash stop 32 ... upper proximity latch magnet

34 ... Lower proximity latch magnet 36 ... Voice coil bias steel

38.Self-weakened voice coil crash stop

39 ... Magnetically weakened contact latch 40 ... Shock rebound member

48 ... Lower yoke-mounted coupling 50, 52, 54, 56 ... Actuator arm

58 ... actuator assembly 60,62,64,66 ... head gimbal assembly

68 ... spindle rotation 70 ... spindle motor

72 ... disc spacer 74 ... disc clamp

76 ... disc separator 78 ... spindle motor hub

80,82 ... disc 84 ... printed circuit board

86 ... main flexible circuit 90 ... track

92 ... inner diameter 94 ... outer diameter

96 ... medium diameter 98 ... preamplifier

100 ... flexible connector 110 ... cover plate

208 ... slider 210 ... read-write head

212 ... Micro-actuator

The present invention relates to a contact start / stop (CSS) hard disk drive, and more particularly to a crash stop for parking a read-write head near a hub of a spindle motor.

Current hard disk drives include an actuator assembly for positioning a read-write head near a track on a rotating disk surface, a voice coil acting on the actuator assembly, and a servo controller for driving the voice coil. The read-write head is in communication with the servo controller and provides feedback, which is used to control the positioning of the read-write head near the track. The read-write head is mounted on a slider which floats on a thin air bearing with a very short distance over the rotating disk surface.

The voice coil motor assembly typically includes a voice coil that rotates at least one actuator arm in response to a servo controller. Each actuator arm typically includes at least one head gimbal assembly having at least one slider. In the voice coil motor assembly, the head gimbal assembly is coupled to an actuator arm.

The hard disk drive may have one or more disks. Each disc may have two surfaces used. For each disk surface used there is provided a slider and an actuator arm for supporting the slider. Hard disk drives typically have one voice coil actuator. The disks are mounted to the spindle motor and rotate with the hub of the spindle motor.

When the hard disk drive is not working, the actuator arm supporting the read-write head is parked near the hub of the spindle motor or away from the hub of the spindle motor. This is to minimize the contact and collision damage between the read-write head and the disk surface.

The present invention relates to a hard disk drive for parking a read-write head close to a hub of a spindle motor. Such hard disk drives are commonly known as "Contact Start / Stop" hard disk drives.

On the other hand, some hard disk drives use another crash stop mechanism that parks the read-write head off the hub of the spindle motor, essentially outside the disk 80, as shown in FIG. 8B. At this time, the head gimbal assembly 60 is parked on a ramp 46 installed outside the disk 80. Such hard disk drives are commonly referred to as "Outside Diameter" (OD) hard disk drives.

The two crash stop mechanisms must withstand rotational shocks in the plane of the disk to prevent damage to the actuator assembly, especially the read-write head. Today's hard disk drives must withstand a rolling shock that lasts for one millisecond or more. At this time, the radial impact strength is approximately 30,000 radians per second.

In conventional CSS hard disk drives, a magnetic latch mechanism has been used as the crash stop mechanism. However, the conventional magnetic latch mechanism has the following problems. A conventional latch mechanism that is commonly used is a magnetic contact latch, which requires a strong initial release force to unpark the actuator assembly. This strong initial release force may be in the range of about 100 to 120 grams. The magnetic contact latches require this strong initial release force for only a short time to unpark the actuator assembly. Thus, since the actuator assembly is initially strongly and rapidly rotating, difficulties arise in controlling it immediately after the initial release of the actuator assembly.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems of the prior art, in particular a yoke assembly of a CSS hard disk drive having a latch mechanism that satisfies rotational shock performance while requiring much smaller initial release force and a voice coil having the same It is an object of the present invention to provide a method of operating a motor assembly and a voice coil motor assembly.

The yoke assembly of the contact start / stop (CSS) hard disk drive according to the present invention for achieving the above technical problem,

An upper yoke plate and a lower yoke plate coupled to face each other;

An upper voice coil fixing magnet and a lower voice coil fixing magnet attached to opposite surfaces of the upper yoke plate and the lower yoke plate, respectively;

An upper proximity latch magnet attached to a side of the upper yoke plate;

A lower proximity latch magnet attached to a side of the lower yoke plate corresponding to the upper proximity latch magnet; And

And a voice coil bias steel provided in a voice coil positioned between the upper voice coil fixing magnet and the lower voice coil fixing magnet.

A magnetic proximity latch is provided by an attractive force applied to the voice coil bias steel from the upper proximity latch magnet and the lower proximity latch magnet.

In the present invention, the upper proximity latch magnet and the lower proximity latch magnet are preferably configured to restrain the voice coil bias steel with an initial release force not greater than 80 grams.

The yoke assembly according to the present invention may further include a yoke crash stop provided on the upper yoke plate and a magnetically weakened voice coil crash stop provided on the voice coil and in contact with the yoke crash stop.

In this case, the magnetically weakened voice coil crash stop may contact the yoke crash stop to provide a magnetically weakened contact latch. In this case, the magnetically weakened voice coil crash stop may be made of a material having a lower permeability than stainless steel.

On the other hand, the magnetically weakened voice coil crash stop may be insulated from contact with the yoke crash stop, thus providing no magnetic contact latch.

In addition, the voice coil motor assembly of a contact start / stop (CSS) hard disk drive according to the present invention for achieving the above technical problem,

An actuator assembly mounted to a base plate by an actuator pivot, the actuator assembly comprising a voice coil coupled to the actuator pivot and a voice coil bias steel attached to the voice coil; And

An upper yoke plate and a lower yoke plate mounted on the base plate, the upper voice coil fixing magnets and the lower voice coil fixing magnets attached to opposite surfaces of the upper yoke plate and the lower yoke plate, respectively; And a yoke assembly including an upper proximity latch magnet attached to a side of the upper yoke plate and a lower proximity latch magnet attached to a side of the lower yoke plate and corresponding to the upper proximity latch magnet.

The upper proximity latch magnet and the lower proximity latch magnet share a magnetic N pole;

The voice coil is located between the upper voice coil fixed magnet and the lower voice coil fixed magnet;

A magnetic proximity latch is provided by an attractive force applied to the voice coil bias steel from the upper proximity latch magnet and the lower proximity latch magnet.

In addition, the operation method of the voice coil motor assembly according to the present invention for achieving the above technical problem,

Instructing a voice coil driver to apply an unparking signal to the voice coil from a voice coil driver electrically connected to the voice coil; And

And triggering the voice coil to unpark the actuator assembly by interacting with the upper voice coil fixed magnet and the lower voice coil fixed magnet.

In the method of operation, the voice coil interacting with the upper voice coil retaining magnet and the lower voice coil retaining magnet may generate a first initial release force pattern to unpark the actuator assembly.

On the other hand, in the method of operation, the voice coil interacting with the upper voice coil fixing magnet and the lower voice coil fixing magnet may generate a second initial release force pattern to unpark the actuator assembly.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. Like reference numerals in the following drawings indicate like elements.

Referring to FIG. 3C, the yoke assembly 8 according to the invention has an upper yoke plate 20 and a lower yoke plate 22 coupled to face each other. The upper voice coil fixing magnet 24 and the lower voice coil fixing magnet 26 are attached to the mutually opposing surfaces of the upper yoke plate 20 and the lower yoke plate 22, respectively. In addition, the yoke assembly 8 according to the present invention has an upper proximity latch magnet 32 and a lower proximity latch magnet 34. The upper proximity latch magnet 32 is attached to the side of the upper yoke plate 20, as shown in FIGS. 1B, 1C, 1D and 3C. The lower proximity latch magnet 34 is attached to a position corresponding to the upper proximity latch magnet 32 on the side of the lower yoke plate 22. The upper proximity latch magnet 32 and the lower proximity latch magnet 34 share a common magnetic N pole.

The yoke assembly 8 according to the invention also comprises a voice coil bias steel 36 attached to the voice coil 14, as shown in FIGS. 1B-1D and 8A. The yoke assembly 8 includes a magnetic proximity latch 6 as a crash stop, as shown in FIG. 1C. The magnetic proximity latch 6 includes the upper coil latch steel 32 and the lower proximity latch magnet 32 in which the voice coil bias steel 36 is disposed in the yoke assembly 8, as shown in FIGS. 1C and 1D. It is formed by being constrained by 34). When such a magnetic proximity latch 6 is used, a relatively small initial release force 198 is required for unparking, as shown in FIG. 4B.

The present invention may also include a magnetically weakened contact latch 39 with a magnetic proximity latch 6, as shown in FIG. 1C. The contact latch 39 includes a yoke crash stop 30 provided in the upper yoke plate 20 and a magnetically weakened voice coil crash stop provided in the voice coil 14 to contact the yoke crash stop 30. (38). Preferably, the yoke crash stop 30 is formed on an upper yoke plate 20 made of stainless steel with permeability. Magnetically weakened voice coil crash stop 38 may be formed of a less permeable material or include an insulating layer. This configuration weakens the initial release force 198 required to release the magnetic contact latch 39. This weakened initial release force 198 is shown in FIGS. 4B and 4C. Insulating the magnetically weakened voice coil crash stop 38 from contact with the yoke crash stop 30 can prevent the magnetic contact latch 39 from being formed. 4B shows the result when the magnetic contact latch is not formed.

1A shows a voice coil crash stop 37 in contact with a yoke crash stop 30 in a conventional CSS hard disk drive. 4A shows a typical initial release force pattern 200 for a conventional CSS hard disk drive. Typical initial release force 198 is between 100 and 120 grams in a conventional 3.5 inch CSS hard disk drive. The initial release force pattern 200 requires interaction between the voice coil 14 and the fixed magnets 24, 26 to provide a force to unpark the actuator assembly 58. At this time, as described above, when unparking, the signals 242 for driving the voice coil 14 should be changed quickly and strongly to bring the operation of the actuator assembly 58 in a controlled state. This consumes significant time and energy, especially for devices using batteries.

1C shows a magnetic proximity latch 6, which is constrained by voice coil bias steel 36 by magnetic proximity latch magnets 32 and 34, and a magnetically weakened voice coil crash in contact with yoke crash stop 30. Show stop 38. In this state, as shown in FIG. 2A, the head gimbal assembly 60 of the voice coil motor assembly 18 is parked near the inner diameter 92.

1B shows the voice coil 14 in contact with the impact repelling member 40 and magnetic proximity latch magnets 32, 34 deviating from the voice coil bias steel 36 in a CSS hard disk drive. In this state, as shown in FIG. 2B, the head gimbal assembly 60 is located near the outer diameter 94.

FIG. 1D shows a state in which the voice coil 14 is positioned between the impact repelling member 40 and the crash stop 30 so that the voice coil bias steel 36 starts to be constrained by the magnetic proximity latch magnets 32 and 34. Shows. In this state, as shown in FIG. 2C, the head gimbal assembly 60 of the actuator assembly 58 is located at an intermediate diameter 96 between the inner diameter 92 and the outer diameter 94.

2D summarizes the mechanical relationships related to the operation of the CSS hard disk drive 10 partially shown in FIGS. 2A to 2C. The CSS hard disk drive 10 includes an actuator assembly 58 mounted on a base plate 12. The actuator assembly 58 is included in the voice coil motor assembly 18, as shown in FIGS. 2A-2C. The actuator assembly 58 includes a voice coil 14 coupled to at least one actuator arm 50. The actuator arm 50 engages a head gimbal assembly 60 that includes at least one slider 208. Each slider 208 includes at least one read-write head 210. The head gimbal assembly 60 may further include at least one micro-actuator 212 that provides fine positioning of the read-write head 210 to follow the track 90 on the rotating disk 80 surface. have. The read-write head 210 interacts with the track 90 to access data stored on the surface of the rotating disk 80. Data access can include any combination of read and write operations involving data stored in track 90.

Meanwhile, as shown in FIG. 5, the CSS hard disk drive 10 may be provided with a plurality of actuator arms 50, 52, 54, 56 and a plurality of head gimbal assemblies 60, 62, 64, 66. have.

2A and 2D, the inner diameter 92 is the disk 80 such that the slider 208, consequently the read-write head 210 is essentially as close as possible to the hub 78 of the spindle motor 70. It is located on the surface of the. When the CSS hard disk drive 10 is not in operation, the actuator assembly 58 is parked. 1C shows voice coil bias steel 36 constrained by upper and lower near latch magnets 32 and 34 in the present invention. In a conventional CSS hard disk drive, as shown in FIG. 4A, the initial release force 198 is large and at least approximately 100 grams. In the embodiment of the present invention using only the magnetic proximity latch 6, as shown in FIG. 4B, the initial release force 198 may be less than approximately 50 grams, for example less than 40 grams. In the present invention, when the magnetic proximity latch 6 and the magnetically weakened contact latch 39 are employed together, as shown in Fig. 4C, the initial release force 198 is about 80 grams or less, for example, It was experimentally confirmed that it is approximately 75 grams.

2B and 2D, the outer diameter 94 is such that the slider 208 with the read-write head 210 is essentially away from the hub 78 of the spindle motor 70, ie the rotating disk 80. ) Near the outside of the surface. In order to keep the actuator assembly 58 operated over the surface of the disk 80, the impact repelling member 40 is provided with an upper yoke plate, as shown in FIGS. 1A-1D, 3B and 3C. 20 is installed. 1B shows the voice coil 14 in contact with the impact repelling member 40.

In FIG. 2D, the median diameter 96 indicates that the slider 208 and the read-write head 210 are located above the track 90. 2C and 2D, the intermediate diameter 96 is located between the inner diameter 92 and the outer diameter 94 in an area utilized for substantially data storage on the disk 80 surface. Within this utilization area, as shown in FIGS. 4B and 4C, the magnetic proximity latch 6 is released.

2A and 2B, a disk separator 76 is shown. The CSS hard disk drive 10 may preferably include the disk separator 76. Moreover, the CSS hard disk drive 10 may have two disks 80, 82 positioned on the base plate 12, with the disk separator 76 between the two disks 80, 82. Located. In addition, the cover plate 110 illustrated in FIG. 6 may be positioned on the disk 80. In such CSS hard disk drive 10, the distance between the disk separator plate 76 and the surface of each disk 80, 82, rather than the thickness of the boundary layer of air formed when the disks 80, 82 rotate during normal operation This small one is preferable. In addition, the distance between the cover plate 110 and the disk 80 and the distance between the base plate 12 and the disk 82 are also preferably smaller than the thickness of the boundary layer.

2A to 2D, reference numeral 68 denotes a disk rotation axis, reference numeral 86 denotes a main flexible circuit, and reference numeral 100 denotes a flexible connector. The main flexible circuit 86 is connected to the preamplifier 98 provided on the actuator arm 50, as shown in FIG. 5.

3A is a front perspective view of the yoke assembly 8 of the CSS hard disk drive 10 according to the present invention. 3B is a rear perspective view of the yoke assembly of the prior art. 3c is a rear perspective view of the yoke assembly 8 according to the invention.

As shown in FIGS. 3A-3C, the yoke assembly 80 and prior art yoke assembly according to the present invention includes an upper yoke plate 20 attached to a lower yoke plate 22. The upper voice coil fixing magnet 24 is attached to the upper yoke plate 20. The lower voice coil fixing magnet 26 is attached to the lower yoke plate 22. The upper yoke plate 20 typically includes a yoke crash stop 30 and an impact repelling member 40. Lower yoke plate 22 includes a yoke mounting coupling 28.

The voice coil motor assembly 18 according to the invention is manufactured as follows. As shown in FIG. 8A, the actuator assembly 58 is mounted to the base plate 12 via an actuator pivot 16. The voice coil 14 is disposed between the upper voice coil fixed magnet 24 and the lower voice coil fixed magnet 26, as shown in FIGS. 1B to 1D. The magnetic proximity latch 6 is generated by an attractive force acting on the voice coil bias steel 36 from the upper proximity latch magnet 32 and the lower proximity latch magnet 34, as shown in FIG. 1C. The yoke assembly 8 is fixedly attached to the base plate 12, as shown in FIGS. 1B-2C.

The yoke mount coupling 28 shown in FIGS. 1B-1D and 3C is fastened to the lower yoke mount coupling 48 shown in FIG. 8A to align the yoke assembly 8 and the actuator assembly 58. . The yoke assembly 8, in which the voice coil 14 is disposed, is mounted to the base plate 12 via the couplings 28, 48.

The present invention applies to a CSS hard disk drive 10 having at least one disk 80. As shown in FIG. 6, the CSS hard disk drive 10 may include one or more disks 80 and 82. And, as shown in the exploded perspective view of FIG. 6, the CSS hard disk drive 10 is manufactured by mounting another component to the base plate 12 together with the voice coil motor assembly 18.

Meanwhile, in FIG. 6, reference numeral 72 denotes a disk spacer for maintaining a gap between the disks 80 and 82, and reference numeral 74 designates the disks 80 and 82 to the hub 78 of the spindle motor 70. Reference numeral 84 denotes a printed circuit board 84 for operating the CSS hard disk drive 10.

The crash stop constructed by combining the magnetic proximity latch 6 and the magnetically weakened contact latch 39 of the present invention requires an initial release force 198 that is significantly reduced than prior art crash stops. As a result of the experiment, the release force pattern 204 is shown in FIG. 4C. These experiments confirm that the CSS hard disk drive 10 using the magnetic proximity latch 6 and the magnetically weakened contact latch 39 satisfies the rotational shock performance requirements sufficiently.

In embodiments that are essentially free of magnetic contact latches 39, it is preferred that the magnetically weakened voice coil crash stop 38 be formed of a non-investable material or insulating layer. This magnetically weakened voice coil crash stop 38 essentially prevents the formation of the magnetic contact latch 39.

On the other hand, in embodiments where essentially no magnetic contact latches 39 are present, the yoke crash stop 30 may be formed of a material or insulating layer that is not permeable. This yoke crash stop 30 essentially prevents the formation of the magnetic contact latch 39.

The present invention provides a method of operating the voice coil motor assembly 18 of a CSS hard disk drive 10 having at least a magnetic proximity latch 6. Referring to FIG. 7, the unlocking signal 242 is applied from the voice coil driver 500 to the voice coil 14, whereby the actuator assembly 58 is unparked. The voice coil 14 is electrically connected to the voice coil driver 500. The servo controller 1030 instructs the voice coil driver 500 to apply a unlocking signal to the voice coil 14. This triggers the voice coil 14 to interact with the upper voice coil fixing magnet 24 and the lower voice coil fixing magnet 26 to unpark the actuator assembly 58. 1C and 1D show the actuator assembly 58 unparked. In the voice coil motor assembly 18, the voice coil 14 interacts with the stationary magnets 24, 26 to generate the first initial release force pattern 202 shown in FIG. 4B.

On the other hand, when the CSS hard disk drive 10 has the magnetic proximity latch 6 and the magnetically weakened contact latch 39 together, the interaction of the voice coil 14 is the second shown in FIG. 4C. Generate an initial release force pattern 204.

9a to 9c show a flow chart of a method of operating the voice coil motor assembly 18 according to the invention carried out along the arrows. Here, the arrows indicate the flow of control or at least one program operation or program thread that is sometimes executed on a computer, a speculative link in an inferential engine, a state in a finite state machine. It refers to the flow of data supporting a device including state tranisitions, and dominant learned responses within a neural network.

The computer used herein may include an instruction processor, but is not limited to this instruction processor. The instruction processor includes at least one instruction processing element and at least one data processing element, each data processing element being controlled by at least one instruction processing element.

9A shows in detail the program steps of the servo controller program system 2000 residing in the servo memory 1040 shown in FIG. 7 for operating the voice coil motor assembly 18. Step 2012 is the step of parking the actuator assembly 18 by instructing the voice coil 14 to apply the parking signal 242. As a result, the head gimbal assembly 60 is parked as shown in FIGS. 1C, 2A, and 2D. As the head gimbal assembly 60 is parked, the actuator assembly 58 is also parked. Step 2022 is to unpark the actuator assembly 58. The servo controller 1030 instructs the voice coil driver 500 to apply the unlocking signal 242 to the voice coil 14. Accordingly, voice coil motor assembly 18 generates an initial release force 198 that acts on actuator assembly 58.

9B details the unparking step 2022 of FIG. 9A. In step 2032, the first initial release force pattern 202 of FIG. 4B is used to command the unparking signal to unpark the actuator assembly 58.

9C details the unparking step 2022 of FIG. 9A. In step 2052, the second initial release force pattern 204 of FIG. 4C is used to command the unparking signal to unpark the actuator assembly 58.

As described above, the present invention has a crash stop composed of a combination of a magnetic proximity latch and a magnetically weakened contact latch, and the crash stop requires an initial release force that is significantly smaller than a conventional crash stop and is rotated. There is an advantage to satisfy the impact performance requirements.

Those skilled in the art will recognize that various applications and modifications to the described preferred embodiments can be made without departing from the scope and spirit of the invention. It is, therefore, to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein.

Claims (18)

In a yoke assembly of a contact start / stop (CSS) hard disk drive, An upper yoke plate and a lower yoke plate coupled to face each other; An upper voice coil fixing magnet and a lower voice coil fixing magnet attached to opposite surfaces of the upper yoke plate and the lower yoke plate, respectively; An upper proximity latch magnet attached to a side of the upper yoke plate; A lower proximity latch magnet attached to a side of the lower yoke plate corresponding to the upper proximity latch magnet; And And a voice coil bias steel provided in a voice coil positioned between the upper voice coil fixing magnet and the lower voice coil fixing magnet. And the magnetic proximity latch is provided by an attractive force applied to the voice coil bias steel from the upper proximity latch magnet and the lower proximity latch magnet. The method of claim 1, And the upper proximity latch magnet and the lower proximity latch magnet are configured to restrain the voice coil bias steel with an initial release force no greater than 80 grams. The method of claim 2, And the initial release force is not greater than 50 grams. The method of claim 1, And a yoke crash stop provided on the upper yoke plate and a magnetically weakened voice coil crash stop provided on the voice coil and in contact with the yoke crash stop. The method of claim 4, wherein And the magnetically weakened voice coil crash stop contacts the yoke crash stop to provide a magnetically weakened contact latch. The method of claim 5, And said magnetically weakened voice coil crash stop is comprised of a material having a less permeability than stainless steel. The method of claim 4, wherein And the magnetically weakened voice coil crash stop is insulated from contact with the yoke crash stop, providing no magnetic contact latch. In a voice coil motor assembly of a contact start / stop (CSS) hard disk drive, An actuator assembly mounted to a base plate by an actuator pivot, the actuator assembly comprising a voice coil coupled to the actuator pivot and a voice coil bias steel attached to the voice coil; And An upper yoke plate and a lower yoke plate mounted on the base plate, the upper voice coil fixing magnets and the lower voice coil fixing magnets attached to opposite surfaces of the upper yoke plate and the lower yoke plate, respectively; And a yoke assembly including an upper proximity latch magnet attached to a side of the upper yoke plate and a lower proximity latch magnet attached to a side of the lower yoke plate and corresponding to the upper proximity latch magnet. The upper proximity latch magnet and the lower proximity latch magnet share a magnetic N pole; The voice coil is located between the upper voice coil fixed magnet and the lower voice coil fixed magnet; And a magnetic proximity latch is provided by an attractive force applied to the voice coil bias steel from the upper proximity latch magnet and the lower proximity latch magnet. The method of claim 8, And the yoke assembly includes a yoke mounting coupling inserted into a lower yoke mounting coupling provided on the base plate. The method of claim 8, And the upper proximity latch magnet and the lower proximity latch magnet are configured to confine the voice coil bias steel with an initial release force no greater than 80 grams. The method of claim 10, And said initial release force is not greater than 50 grams. The method of claim 8, And a yoke crash stop provided on the upper yoke plate and a magnetically weakened voice coil crash stop provided on the voice coil and in contact with the yoke crash stop. The method of claim 12, And the magnetically weakened voice coil crash stop is in contact with the yoke crash stop to provide a magnetically weakened contact latch. The method of claim 13, And said magnetically weakened voice coil crash stop is comprised of a material having a less permeability than stainless steel. The method of claim 12, And the magnetically weakened voice coil crash stop is insulated from contact with the yoke crash stop, providing no magnetic contact latch. The method of operating the voice coil motor assembly of claim 8, Instructing a voice coil driver to apply an unparking signal to the voice coil from a voice coil driver electrically connected to the voice coil; And Triggering the voice coil to interact with the upper voice coil fixing magnet and the lower voice coil fixing magnet to unpark the actuator assembly. The method of claim 16, And wherein said voice coil interacting with said upper voice coil retaining magnet and said lower voice coil retaining magnet generates a first initial release force pattern for unparking said actuator assembly. The method of claim 16, And the voice coil interacting with the upper voice coil retaining magnet and the lower voice coil retaining magnet generates a second initial release force pattern for unparking the actuator assembly.

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