BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1
a is a perspective view of a conventional disk drive unit;
FIG. 1
b is a partial perspective view of the disk drive unit shown in FIG. 1a;
FIG. 2
a is an exploded, perspective view of a conventional HGA;
FIG. 2
b is a partial top plan view of the assembled HGA shown in FIG. 2a;
FIG. 2
c is a partial, side elevational view of the assembled HGA shown in FIG. 2a;
FIG. 2
d is a diagrammatic view illustrating a leading edge of a slider shown in FIG. 2c hitting PZT elements during a vibration or shock event;
FIG. 3
a is an assembled, perspective view of a first embodiment of a HGA according to the present invention;
FIG. 3
b is a partial, enlarged perspective view of the HGA of FIG. 3a;
FIG. 3
c is an exploded, perspective view of the HGA of FIG. 3a;
FIG. 3
d is a partial side elevational view of the HGA of FIG. 3a, showing the relationship between the positions of a transition surface of the slider and the PZT elements when a vibration or shock happens;
FIG. 3
e is a plan view of the slider shown in FIG. 3d seen from a slider mounting surface of the slider;
FIG. 4 is a perspective view of a second embodiment of a slider according to the present invention;
FIG. 5
a illustrates a testing system for testing the shock performance of the disk drive unit;
FIG. 5
b shows a testing data acquired by testing the conventional disk drive unit and a disk drive unit incorporating the present slider respectively by the testing system shown in FIG. 5b;
FIG. 6 is a flow chart of manufacturing the HGA according to the present invention;
FIGS. 7
a-7b are views illustrating steps of manufacturing the slider according to an embodiment of the present invention;
FIG. 8
a-8b are views illustrating steps of manufacturing the slider according to another embodiment of the present invention; and
FIG. 9 is a perspective view of a disk drive unit according to the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Various preferred embodiments of the instant invention will now be described with reference to the figures, wherein like reference numerals designate similar parts throughout the various views. As indicated above, the instant invention is designed to provide an improved slider for a head gimbal assembly. The slider has a leading edge, a trailing edge opposite to the leading edge, an air-bearing surface connecting the leading edge and the trailing edge, and a slider mounting surface opposite to the air-bearing surface. A sharpened edge intersected by the leading edge and the slider mounting surface is machined to form a transition surface, such as a step-like surface recessed into the slider, or a smooth curved transition surface. The transition surface intersects the leading edge at a first cross line, and the distance between the first cross line and the air-bearing surface is less than that between the slider mounting surface and the air-bearing surface. The transition surface intersects the slider mounting surface at a second cross line, and the distance between the second cross line and the trailing edge is less than that between the leading edge and the trailing edge. Compared with a conventional slider with sharpened edge, the transition surface of the slider of the invention spaces the PZT elements farther, so the transition surface of the slider of the invention is not easy to hit the PZT elements when a vibration or shock happens. Even if the transition surface hits the PZT elements, the damage to the PZT elements from the transition surface is far less than that from the sharpened edge of the conventional slider because the contact area between the transition surface and the PZT elements of the invention becomes larger than that of the prior art.
FIGS. 3
a-3c illustrate a head gimbal assembly (HGA) 200 incorporating the slider according to an exemplary embodiment of the present invention. The HGA 200 comprises a suspension 280 and a slider 203 held on the suspension 280. The suspension 280 includes a base plate 232, a hinge 231, a flexure 222, and a load beam 224, which are assembled together.
The flexure 222 has a PZT element mounting area 228, and a slider mounting area 207 at an end thereof. A plurality of electrical pads, such as four electrical pads 237 are formed on the PZT element mounting area 228. Two PZT elements 235 are mounted on the PZT element mounting area 228, each of which has a plurality of connection pads 236 to electrically connect with the electrical pads 237. A plurality of electrical pads, such as four electrical pads 211 are formed on the slider mounting area 207. The slider 203 is mounted on the slider mounting area 207, which has a plurality of connection pads 215 (shown in FIG. 3d ) to electrically connect with the electrical pads 211. The electrical pads 211 and the connection pads 215 are connected by electrical connection balls (gold ball bonding or solder ball bonding, GBB or SBB) 216 (shown in FIG. 3d ).
In the embodiment, the flexure 222 further comprises a plurality of multi-traces 212, one end of which connect with a control system (not shown), and the other end of which connect with the electrical pads 237, 211, respectively. Thus the control system can respectively control the slider 203 and the PZT elements 235 through the multi-traces 212. In addition, a dimple 225 is formed on the load beam 224. When the slider 203 is flying above the disk, the dimple 225 supports a center area of the bottom of the slider 203, which keeps the load force from the load beam 224 always being applied to the center of the slider 103 evenly, thus ensuring the slider 103 have a good flying performance.
Referring to FIGS. 3c-3e, the slider 203 has a leading edge 219, a trailing edge 218 opposite to the leading edge 219, an air-bearing surface 217 connecting the leading edge 219 with the trailing edge 218, and a slider mounting surface 230 opposite to the air-bearing surface 217. The trailing edge 218 has a read/write element and the above-mentioned connection pads 215. The slider mounting surface 230 is partially mounted on the slider mounting area 207 of the flexure 222. The slider 203 further comprises a transition surface 238 which connects the leading edge 219 with the slider mounting surface 230. The transition surface 238 intersects the leading edge 219 at a first cross line 243 and intersects the slider mounting surface 230 at a second cross line 242. The distance between the first cross line 243 and the air-bearing surface 217 is less than that between the slider mounting surface 230 and the air-bearing surface 217, that is, the width T of the slider 203. The distance between the second cross line 242 and the trailing edge 218 is less than that between the leading edge 219 and the trailing edge 218, that is, the length L of the slider 203. In the present embodiment, the transition surface 238 is a smooth curved surface to connect the slider mounting surface 230 with the leading edge 219.
Referring to FIG. 3d, a parallel gap is formed between the slider mounting surface 230 and the PZT elements 235. The parallel gap keeps the flying slider 203 from interfering with the PZT elements 235. When the disk drive unit is suffered from vibration or shock, the slider 203 rotates against the dimple 225 toward the trailing edge 218 or the leading edge 219. When the slider 203 rotates toward the leading edge 219, the leading edge 219 gradually approaches the PZT elements 235. Since the transition surface 238 is recessed into the slider 203, the transition surface 238 is not easy to hit the PZT elements 235. Even if the transition surface 238 hits the PZT elements 235, the damage to the PZT elements 235 from the transition surface 238 is far less than that from the sharpened edge of the conventional slider because the contact area between the transition surface 238 and the PZT elements 235 is far larger.
FIG. 4 illustrates a slider 303 according to a second embodiment of the invention. The slider 303 has a step-like transition surface 338. Similar to the curved transition surface 238 of the slider 203, the step-like transition surface 338 intersects the slider mounting surface 230 at a second cross line 342, and the distance between the second cross line 342 and the trailing edge 218 is less than the length of the slider 303. The step-like transition surface 338 intersects the leading edge 219 at a first cross line 343, and the distance between the first cross line 343 and the air-bearing surface 217 is less than the width of the slider 303. The step-like transition surface 338 functions comparably with the curved transition surface 238, and the step-like transition surface 338 is easier to be formed.
FIG. 5
a illustrates a lilt drop testing system 400 (such as a lilt drop testing system) for testing the shock performance of the disk drive unit. As shown in FIG. 5a, the testing system 400 comprises a horizontal bottom plate 401 and a support plate 402 vertically mounted on the bottom plate 401. The support plate 402 has a pivot hinge 405 formed at its top end. During testing the disk drive unit 403, one end of the disk drive unit 403 is pivotally connected with the hinge 405, and the other end is lifted to a height H from the bottom plate 401. The height H is drop height of the disk drive unit 403. In an embodiment, ten groups of conventional disk drive units and ten groups of present disk drive units are respectively tested, the drop height is selectively set to 3 inch, 4 inch, or 5 inch, the drop end of the disk drive unit is selectively set to the connector end or the no connector end, and the disk drive unit is selectively set as facing up or facing down. During every testing, the disk drive unit is freely rotated and drops to the bottom plate 401. After every drop shock after each drop height, the tester checks the PZT elements to see if there are any damage to the disk drive unit. The testing data are listed in FIG. 5b wherein the symbol 0 denotes the disk drive unit past the test, and the symbol X denotes the disk drive unit did not pass the test. It can be seen from FIG. 5b, when the drop height is gradually increased, such as increased to 5 inch, most conventional disk drive units did not pass the test, while all of the present disk drive units past the test. This shows that the present disk drive unit has a better shock performance that the conventional disk drive unit.
Referring to FIG. 6, a method of manufacturing the HGA according to the present invention comprises the steps of: 1) providing a row bar constituted by a group of juxtaposed sliders, each slider having a leading edge, a trailing edge opposite to the leading edge, an air-bearing surface connecting the leading edge and the trailing edge, and a slider mounting surface opposite to the air-bearing surface (step 701); 2) machining the row bar at intersection of the leading edge and the slider mounting surface to form a transition surface (step 702); 3) cutting the row bar into individual sliders (step 703); 4) providing a suspension and a micro-actuator having PZT elements (step 704); and 5) assembling one of the sliders, the micro-actuator and the suspension together with the micro-actuator positioned between the slider and the suspension, and the PZT elements facing the slider mounting surface (step 705). Preferably, the transition surface is machined by lapping.
FIGS. 7
a-7b illustrate steps of manufacturing the slider according to an embodiment of the present invention. As shown in FIG. 7a, a row bar 501 is constituted by a group of juxtaposed sliders 505. Each slider 505 has a slider mounting surface 504 and a leading edge 503 intersecting with the slider mounting surface 504. Between every two adjacent sliders 505 there is a cutting surface 506. In the present embodiment, a lapping device, such as a lapping wheel with a slap edge 502 is used for lapping the intersection of the slider mounting surface 504 and the leading edge 503 to form a transition surface 507. In the embodiment, the transition surface 507 is an inclined surface. Then, referring to FIG. 7b, the row bar 501 is cut into individual sliders 505 along the cutting surfaces 506 after the transition surface 507 is formed.
FIGS. 8
a-8b illustrate steps of manufacturing the slider according to another embodiment of the present invention which is similar to that shown in FIGS. 7a-7b. The difference is in that the transition surface 605 in the embodiment is lapped into a step-like surface.
Referring to FIG. 9, according to an embodiment of the present invention, a disk drive unit can be attained by assembling a housing 205, a disk 201, a spindle motor 202 for spinning the disk 201, a VCM 209, and a drive arm 204 with the HGA 200 of the present invention. The HGA 200 may include the suspension 280 and the slider 203, 303 or 505 held on the suspension 280. Because the structure and/or assembly process of disk drive unit of the present invention are well known to persons ordinarily skilled in the art, a detailed description of such structure and assembly is omitted herefrom. In addition, any other suitable type disk drive unit can also be applied to the present invention, so long as it has an improved HGA of the present invention.
The foregoing description of the present invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed, and obviously many modifications and variations are possible in light of the above teaching. Such modifications and variations that may be apparent to those skilled in the art are intended to be included within the scope of this invention as defined by the accompanying claims.
Patent Application
20080024920
