Disc drive actuator bearing cartridge assembly with temperature induced rotational torque mitigation

Patent metadata

Field	Value
Publication number	US-9620155-B2
Application number	US-201514807546-A
Country	US
Kind code	B2
Filing date	Jul 23, 2015
Priority date	Jul 23, 2015
Publication date	Apr 11, 2017
Grant date	Apr 11, 2017

Abstract

Various aspects of the present disclosure are directed toward a disc drive actuator assembly including an e-block, a bearing, and a sleeve. The bearing includes an inner race, an outer race and a plurality of balls between the inner and outer races. The inner race being coupled to a pivot shaft of a disc drive, and the bearing being configured and arranged to facilitate rotation of the e-block around the pivot shaft. The sleeve coupling the outer race of the bearing to the e-block, and includes a groove along an inner diameter of the sleeve adjacent the outer race. The groove and outer race mitigate rotational torque changes due to thermal effects upon the disc drive actuator assembly by allowing the outer race of the bearing to deform into or away from the groove and therein mitigate or prevent the generation of certain forces in bearings.

First claim

What is claimed is:

1. A disc drive actuator assembly comprising:
an e-block including one or more actuator arms;
a bearing including an inner race, an outer race and a plurality of balls between the inner and outer races, the inner race being coupled to a pivot shaft of a disc drive, the bearing being configured and arranged to facilitate rotation of the e-block around the pivot shaft; and
a sleeve coupling the outer race of the bearing to the e-block, the sleeve including a groove along an inner diameter of the sleeve and adjacent the outer race, the groove being configured and arranged with the bearing to facilitate deformation of the outer race of the bearing relative to the sleeve.

2. The disc drive actuator assembly of claim 1 , wherein the groove is configured and arranged with the bearing to mitigate rotational torque variation upon the disc drive actuator assembly via the relative-deformation of the outer race of the bearing and the sleeve.

3. The disc drive actuator assembly of claim 1 , wherein
the outer race has a coefficient of thermal expansion that is different than a coefficient of thermal expansion of the sleeve, and
the groove is configured and arranged with the bearing to mitigate the generation of forces induced by thermal expansion or thermal contraction of the disc drive actuator assembly, associated with the different coefficients of thermal expansion and changes in temperature during operation of the disc drive, by deforming the outer race of the bearing relative to the sleeve.

4. The disc drive actuator assembly of claim 1 , wherein the groove is configured and arranged with the outer race of the bearing to limit rotational torque variation in the bearing to a target rotational torque over a predefined operational temperature range, by facilitating relative deformation of the outer race of the bearing and the sleeve under thermal expansion and thermal contraction conditions corresponding to upper and lower limits of the temperature range.

5. The disc drive actuator assembly of claim 1 , wherein the groove is further configured and arranged with the outer race to maintain rotational torque of the bearing within 10% of a target rotational torque over a target operational temperature range of the disc drive, by mitigating forces generated due to thermal expansion via the relative deformation of the outer race of the bearing and the sleeve.

6. The disc drive actuator assembly of claim 1 , wherein
the inner and outer races of the bearing are biased relative to inner and outer races of another adjacent bearing, the adjacent inner races being biased toward one another along a length of the pivot shaft and the adjacent outer races being biased away from one another along the length of the pivot shaft,
the inner and outer races are configured and arranged to establish a rotational torque of the e-block relative to the pivot shaft via the biased adjacent inner races and the biased adjacent outer races, and
the groove is configured and arranged with the bearings to mitigate the generation of forces due to increased bearing temperature via deformation of the outer race adjacent the groove.

7. The disc drive actuator assembly of claim 1 , further including an adhesive that couples surfaces of the outer race and the sleeve adjacent the groove, the coupled surfaces being configured and arranged to expand and contract together while surfaces of the outer race and the groove deform relative to one another.

8. The disc drive actuator assembly of claim 1 , wherein
the sleeve exhibits a first coefficient of thermal expansion;
the bearing exhibits a second coefficient of thermal expansion that is different than the first coefficient of thermal expansion, whereby expansion and contraction of the bearing is different than expansion and contraction of the sleeve under common temperature conditions; and
the outer race and groove are designed to mitigate the generation of forces induced by said different expansion and contraction of the bearing, relative to the expansion and contraction of the sleeve.

9. The disc drive actuator of claim 1 , wherein the sleeve is configured and arranged to maintain shape in response to induced forces upon the sleeve under conditions in which the outer race deforms adjacent the groove.

10. An apparatus comprising:
a base deck including a pivot shaft fixed relative to the base deck;
a plurality of storage mediums; and
a disc drive actuator assembly including
a transducer configured and arranged to access data storage locations on one of the plurality of storage mediums,
an e-block configured and arranged to position the transducer over the one of the plurality of storage mediums, and
a bearing including inner and outer races and a plurality of balls therebetween, the inner race of each bearing coupled to a pivot shaft of the disc drive, and the bearing configured and arranged to facilitate rotation of the e-block around the pivot shaft; and
a sleeve coupling the outer race of the bearing to the e-block, the sleeve including a groove along an inner diameter of the sleeve and adjacent at least a portion of the outer race, the groove being configured and arranged with the bearing to mitigate rotational torque variation upon the disc drive actuator assembly by allowing the outer race of the bearing to deform relative to the sleeve.

11. The apparatus of claim 10 , wherein the sleeve is further configured and arranged with the bearing to mitigate the generation of forces induced by thermal expansion and contraction of the disc drive actuator assembly, associated with changes in temperature during operation of the disc drive, by deforming the outer race of the bearing relative to the groove.

12. The apparatus of claim 10 , wherein the sleeve is configured and arranged with the outer race of the bearing to mitigate changes in rotational torque in the bearing by mitigating thermally induced forces in the outer race, exceeding a target rotational torque of the bearing over a predefined operational temperature range, via deformation of the outer race relative to the groove.

13. The apparatus of claim 10 , wherein the groove is further configured and arranged with the outer race to maintain the rotational torque of the bearing within 10% of a target rotational torque over a target operational temperature range of the disc drive, by compensating or preventing excess force induced via thermal expansion or contraction of the disc drive actuator assembly.

14. The apparatus of claim 10 , wherein
the sleeve has a coefficient of thermal expansion that is different than a coefficient of thermal expansion of the bearing, and
the groove is configured and arranged with the sleeve and the bearing to mitigate the generation of forces induced by disparate thermal expansion or thermal contraction characteristics of the sleeve and of the bearing, by deforming the outer race of the bearing relative to the sleeve.

15. The apparatus of claim 10 , wherein the sleeve is configured and arranged to maintain shape in response to induced forces upon the sleeve under conditions in which the outer race deforms relative to the groove.

16. A method for mitigating rotational torque variation of a bearing in a disc drive apparatus having a base deck including a pivot shaft, a disc drive actuator assembly that includes an e-block rotationally fixed relative to the base via the pivot shaft, a plurality of storage mediums, and a transducer coupled to the e-block for accessing data on the plurality of storage mediums, the method comprising:
providing a bearing having inner and outer races and a pl

Assignees

• Seagate Technology Llc

Inventors

• Shi Zheng
• Benson Glenn A
• Lind Jeffrey Robert

Classifications

• G11B5/4813 Primary

  Mounting or aligning of arm assemblies, e.g. actuator arm supported by bearings, multiple arm assemblies, arm stacks or multiple heads on single arm (G11B5/484 takes precedence) · CPC title

• G11B5/5565

  system adaptation for compensation of variations of physical parameters, e.g. temperature · CPC title