The present invention relates to disk drives, and more particularly to a method and system for providing a pivot assembly utilizing solid lubrication.
The head stack assembly 6 includes a swing arm 7 having a cylindrical bore 8, a conventional pivot assembly 10 having a shaft 9. The heads 5 reside at the distal end of the swing arm 7. The conventional pivot assembly 10 includes ball bearings (not shown in
Although the conventional pivot assembly 10 functions, one of ordinary skill in the art will readily recognize that there are several drawbacks to its use that adversely affect performance and scalability. During use, dynamic vibrations are generated by physical contact between the balls 15 and 16 and races 12A, 12B, 13A, and 13B as the balls 15 and 16, respectively, roll in the races 12A, 12B, 13A, and 13B. Typically, lubrication is provided by bearing oil and grease. As a result, the balls 15 and 16 typically run macroscopically even and smooth in the races 12A, 12B, 13A, and 13B, respectively. However, on a microscopic level, the races 12A, 12B, 13A, and 13B may be uneven and rough. In addition, the shapes of the balls 15 and 16 may vary from spheres. These microscopic imperfections in the races 12A, 12B, 13A, and 13B, as well as imperfections in the sphericity of the balls 15 and 16, respectively, may cause vibrations. These vibrations adversely affect the performance of the conventional pivot assembly 10. Further, damage to the balls 15 and 16 may be incurred during shocks to the bearings 12 and 13. In particular, contact surfaces for the balls 15 and 16 are small. Pressures resulting from contact between the races 12A, 12B, 13A and 13B and the corresponding balls 15 and 16, respectively, may thus exceed the yield strength of the ball material. As a result, permanent deformation of the balls 15 and 16 and/or the races 12A, 12B, 13A, and 13B may occur. Such deformations adversely affect performance of the conventional pivot assembly 10. Moreover, the conventional pivot assembly 10 may be subject to non-repeatable error in writing and reading information at predetermined positions of the disks 4. In particular, misalignment of the bearings 12 and 13 around the shaft 9 induces runout of the swing arm 7 that is not repeatable. As a result, non-repeatable errors may occur in the position of the magnetic heads 5. Further, the physical size of the bearings 13 and 13 is also limited in scalability. In particular, the use of mechanical bearings 12 and 13 may be limited to fixed dimensions. As a result, it is difficult to reduce the size of the conventional pivot assembly 10 to be used in applications requiring smaller disk drives.
Accordingly, what is needed is a method and system for providing a pivot assembly that has improved performance and/or scalability. The present invention addresses such a need.
The present invention provides a method and system for providing a disk drive pivot assembly. The method and system comprise providing a sleeve, a shaft, and a solid lubrication. The sleeve includes a sleeve bearing surface that defines at least a portion of an aperture within the sleeve. The shaft has a shaft bearing surface and is rotatable with respect to the sleeve. The shaft bearing surface abuts the sleeve bearing surface. The solid lubrication resides between the shaft bearing surface and the sleeve bearing surface.
According to the method and system disclosed herein, the present invention provides a disk drive pivot assembly that has reduced vibration, reduced shock damage, and improved alignment.
The present invention relates to disk drive assemblies. The following description is presented to enable one of ordinary skill in the art to make and use the invention and is provided in the context of a patent application and its requirements. Various modifications to the preferred embodiments and the generic principles and features described herein will be readily apparent to those skilled in the art. Thus, the present invention is not intended to be limited to the embodiments shown, but is to be accorded the widest scope consistent with the principles and features described herein.
The present invention provides a method and system for providing a disk drive pivot assembly. The method and system comprise providing a sleeve, a shaft, and a solid lubrication. The sleeve includes a sleeve bearing surface that defines at least a portion of an aperture within the sleeve. The shaft has a shaft bearing surface and is rotatable with respect to the sleeve. The shaft bearing surface abuts the sleeve bearing surface. The solid lubrication resides between the shaft bearing surface and the sleeve bearing surface.
The present invention will be described in terms of particular embodiments of the disk drive pivot assembly. However, one of ordinary skill in the art will readily recognize that the method and system are consistent with other components having analogous components and/or functions.
Because of the use of the solid lubrication 130 in conjunction with the shaft 120 and sleeve 110, the use of ball bearings can be avoided. Consequently, the problems of runout, vibration, and/or deformation of the balls or races may be avoided. In addition, the pivot assembly 100 may have be made smaller and, therefore, my be capable of being used in smaller disk drives. Consequently, performance and scalability of the pivot assembly 100 may be improved. Moreover, the pivot assembly 100 is relatively simple in the design, thereby facilitating manufacturing and assembly. The number of parts 110, 120, and 130 of the pivot assembly 100 is also relatively low. Thus, cost and assembly time may be reduced.
The shaft 141 preferably has thrust plates 142 and 143 mounted on each end. The shaft 141 preferably includes a threaded mounting end 141A that is configured to through an opening in the base plate of a disk drive (not shown). In such an embodiment, a nut (not shown) may be threaded on the extension 141A to affix the shaft 141 to the base plate. In another embodiment, other means of attaching the extension 141A and/or the shaft 141 to the base plate are available. For example an interference fit, retaining clip, glue, or other mechanisms might be used. At this end, the shaft 141 also preferably includes a shoulder 141B which preferably rests on an upraised portion (not shown) of a base plate (not shown), such as the base plate 2 depicted in
The sleeve 144 is preferably cylindrical in shape. A swing arm (not shown), such as the swing arm 7 depicted in
In the configuration shown, the contact surfaces 141C and 144A of the shaft 141 and the sleeve 144 define where the shaft 141 and sleeve 144 might contact at a gap 145. The gaps 146 and 147 exist between the thrust plates 142 and 143, respectively, and the sleeve 144. Consequently, solid lubrication 148 and 149 resides between the contact surfaces 141C and 144A, as well as in the gaps 146 and 147. Alternatively, the solid lubrication can be applied in the form of film, as with techniques such as sputter deposition, diffusion, and surface treatments, to one (or both) of the contact surfaces 141C and 144A between the pivot shaft 141 and the surrounding sleeve 144. The solid lubrication may also be applied to at least one of the contact surfaces 142A and 144B between thrust plate 142 and sleeve 144, respectively, and/or to at least one of the contact surfaces 143A and 144C between the thrust plate 143 and the sleeve 144, respectively.
Thus, the pivot assembly 140 need not use ball bearings. Instead, the combination of the shaft 141, the sleeve 144, the thrust plates 142 and 143, and the solid lubrication 148 and 149 are used. Consequently, the problems of runout, vibration, and/or deformation of the balls or races may be avoided. In addition, the pivot assembly 140 may have be made smaller and, therefore, my be capable of being used in smaller disk drives. Consequently, performance and scalability of the pivot assembly 140 may be improved. Moreover, the pivot assembly 140 is relatively simple in the design, thereby facilitating manufacturing and assembly. The number of parts 141, 142, 143 and 144 of the pivot assembly 140 is also relatively low. Thus, cost and assembly time may be reduced.
Referring back to
The sleeve 154 is preferably cylindrical in shape. The sleeve 154 is also coupled to the counterplate 159. Although the counterplate 159 is preferably affixed to the sleeve 54 using glue, other mechanisms can be used. A swing arm (not shown), such as the swing arm 7 depicted in
In the configuration shown, the contact surfaces 151C and 154A of the shaft 151 and the sleeve 154 define where the shaft 151 and sleeve 154 might contact. Moreover, the sleeve 154 and thrust plate 152, as well as the counterplate 159 and thrust plate 152 may contact. Consequently, solid lubrication 160 resides between the contact surfaces 151C and 154A, in the gap 155. The solid lubrication 161 preferably also resides in gaps 156 and 157, which exist between the thrust plate 152 and the counterplate 159 and between the thrust plate 152 and the sleeve 154, respectively.
As discussed above, the solid lubrication preferably resides in one or more the areas described. The solid lubrication might also be applied, for example in the form of film. Techniques for providing such films include sputter deposition, diffusion, and surface treatments, to one (or both) of the contact surfaces 151C and 154A between the shaft 151 and the surrounding sleeve 154, and to one (or both) of the contact surfaces 152A and 154B between thrust plate 152 and the sleeve 154, and to one (or both) of the contact surfaces 152B and 159C between thrust plate 152 and counterplate 159.
Thus, the pivot assembly 150 need not use ball bearings. Instead, the combination of the shaft 151, the sleeve 154, the thrust plate 152 and counterplate 159, and the solid lubrication 160 and 161 are used. Consequently, the problems of runout, vibration, and/or deformation of the balls or races may be avoided. In addition, the pivot assembly 150 may have be made smaller and, therefore, my be capable of being used in smaller disk drives. Consequently, performance and scalability of the pivot assembly 150 may be improved. Moreover, the pivot assembly 150 is relatively simple in the design, thereby facilitating manufacturing and assembly. The number of parts of the pivot assembly 150 is also relatively low. Thus, cost and assembly time may be reduced.
The shaft 171 has thrust plates 172 and 173 mounted on both ends. The shaft 171 also includes an extension 171A on which swing arm (not shown), such as the swing arm depicted in
The shaft 171 rotates relative to the fixed cylindrical sleeve 174. The sleeve 174 is mounted to a base plate (not shown) by glue, interference fit, or the like. The sleeve 174 is also coupled to a base plate (not shown), such as the base plate 2 depicted in
In the configuration shown, the contact surfaces 171C and 174A of the shaft 171 and the sleeve 174 define where the shaft 171 and sleeve 174 might contact at a gap 175. The gaps 176 and 177 exist between the thrust plates 172 and 173, respectively, and the sleeve 174. Consequently, solid lubrication 178 and 179 resides between the contact surfaces 171C and 174A, as well as in the gaps 176 and 177. In one embodiment, solid lubrication 178 and 179 might be applied in the form of film, for example using techniques such as sputter deposition, diffusion, and surface treatments. Thus, the solid lubrication 178 and 179 may be applied to at least one of the following: one or both of the contact surfaces 171C and 174A, between the pivot shaft 171 and the sleeve 174, and one or more of the contact surfaces 172A and 174C between thrust plate 172 and sleeve 174, and to one or both of the contact surfaces 173A and 174C between the thrust plate 173 and the sleeve 174.
Thus, the pivot assembly 170 need not use ball bearings. Instead, the combination of the shaft 171, the sleeve 174, the thrust plates 172 and 173, and the solid lubrication 178 and 179 are used. Consequently, the problems of runout, vibration, and/or deformation of the balls or races may be avoided. In addition, the pivot assembly 140 may have be made smaller and, therefore, my be capable of being used in smaller disk drives. Consequently, performance and scalability of the pivot assembly 140 may be improved. Moreover, the pivot assembly 170 is relatively simple in the design, thereby facilitating manufacturing and assembly. The number of parts 171, 172, 173 and 174 of the pivot assembly 170 is also relatively low. Thus, cost and assembly time may be reduced.
Referring back to
The shaft 181 rotates relative to the fixed cylindrical sleeve 184. The sleeve 184 is also coupled to a base plate (not shown), such as the base plate 2 depicted in
In the configuration shown, the contact surfaces 181C and 184A of the shaft 181 and the sleeve 184 define where the shaft 181 and sleeve 184 might contact at gap 185. The gaps 186 and 187 exist between the thrust plate 182 and the counterplate 189 and the thrust plate 182 and the sleeve 184, respectively. Moreover, the sleeve 184 and thrust plate 182, as well as the counterplate 189 and thrust plate 182 may contact. Consequently, solid lubrication 190 resides between the contact surfaces 181C and 184A, in the gaps 155. The solid lubrication 191 preferably also resides in gaps 186 and 187, which exist between the thrust plate 182 and the counterplate 189 and between the thrust plate 182 and the sleeve 184, respectively.
As discussed above, the solid lubrication preferably resides in one or more the areas described. The solid lubrication might also be applied, for example in the form of film. Techniques for providing such films include sputter deposition, diffusion, and surface treatments, to one (or both) of the contact surfaces 181C and 184A between the shaft 181 and the surrounding sleeve 184, and to one (or both) of the contact surfaces 182A and 184B between thrust plate 182 and the sleeve 184, and to one (or both) of the contact surfaces 182B and 189A between thrust plate 182 and counterplate 189.
Thus, the pivot assembly 180 need not use ball bearings. Instead, the combination of the shaft 181, the sleeve 184, the thrust plate 182, the counter plate 189, and the solid lubrication 190 and 191 are used. Consequently, the problems of runout, vibration, and/or deformation of the balls or races may be avoided. In addition, the pivot assembly 180 may have be made smaller and, therefore, my be capable of being used in smaller disk drives. Consequently, performance and scalability of the pivot assembly 140 may be improved. Moreover, the pivot assembly 180 is relatively simple in the design, thereby facilitating manufacturing and assembly. The number of parts of the pivot assembly 180 is also relatively low. Thus, cost and assembly time may be reduced.
A sleeve 110 including an aperture 112 is provided, via step 302. The aperture 110 is defined to include at least one bearing surface. In one embodiment, step 302 includes providing a counterplate (not shown in
Thus, the pivot assembly 100, 140, 150, 170, and/or 180 may be provided using the method 300. As a result, the benefits of the pivot assembly 100, 140, 150, 170, and/or 180 may be achieved.
A method and system for providing a disk drive pivot assembly has been disclosed. The present invention has been described in accordance with the embodiments shown, and one of ordinary skill in the art will readily recognize that there could be variations to the embodiments, and any variations would be within the spirit and scope of the present invention. Accordingly, many modifications may be made by one of ordinary skill in the art without departing from the spirit and scope of the appended claims.
This application is claiming under 35 USC 119(e) the benefit of provisional Patent Application Ser. No. 60/538,157, filed Jan. 22, 2004.
Number | Date | Country | |
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60538157 | Jan 2004 | US |