Bearing device with pre-load configuration, method for producing same, and hard disk drive device

Patent metadata

Field	Value
Publication number	US-11798584-B2
Application number	US-202217656910-A
Country	US
Kind code	B2
Filing date	Mar 29, 2022
Priority date	Apr 1, 2021
Publication date	Oct 24, 2023
Grant date	Oct 24, 2023

Abstract

There is provided a bearing device including: a tubular sleeve; a shaft held inside the sleeve; and a first bearing, a second bearing, a third bearing, and a fourth bearing, rotatably holding the shaft with respect to the sleeve and arranged in this order in an axial direction. An outer circumferential surface of an outer ring of each of the first to fourth bearings is fixed to an inner circumferential surface of the sleeve, a gap is provided between inner circumferential surfaces of inner rings of the second and third bearings and the shaft, and a spring applying a constant pre-load is provided between the inner rings of the second and third bearings.

First claim

The invention claimed is:

1. A bearing device comprising:
an outer member having a tubular shape;
a shaft member held inside the outer member; and
a first bearing, a second bearing, a third bearing, and a fourth bearing, rotatably holding the shaft member with respect to the outer member and arranged in this order in an axial direction, wherein
an outer circumferential surface of an outer ring of each of the first bearing, the second bearing, the third bearing, and the fourth bearing is fixed to an inner circumferential surface of the outer member, and
a spring applying a constant pre-load is provided between inner rings of the second bearing and the third bearing.

2. The bearing device according to claim 1 , wherein the outer circumferential surface of the outer ring of each of the first bearing, the second bearing, the third bearing, and the fourth bearing is adhered to the inner circumferential surface of the outer member with an adhesive.

3. The bearing device according to claim 2 , wherein the adhesive is an anaerobic adhesive.

4. The bearing device according to claim 1 , wherein a step portion protruding inward in a radial direction is formed in a central portion of the inner circumferential surface of the outer member, and
an outer ring of each of the second bearing and the third bearing is in contact with the step portion.

5. The bearing device according to claim 4 , wherein the spring is disposed inside the step portion of the outer member.

6. The bearing device according to claim 1 , wherein a sealing member is provided between the shaft member and at least one of the inner rings of the second bearing and the third bearing.

7. The bearing device according to claim 6 , wherein the sealing member is an elastic adhesive.

8. The bearing device according to claim 7 , wherein the sealing member is provided between an inner ring of the third bearing and the shaft member, and
no sealing member is provided between an inner ring of the second bearing and the shaft member.

9. The bearing device according to claim 7 , wherein the elastic adhesive has a hardness set to Shore A 70 or less.

10. The bearing device according to claim 9 , wherein the elastic adhesive has the hardness set to Shore A 60 or less.

11. The bearing device according to claim 10 , wherein the elastic adhesive has the hardness set to Shore A 50 or less.

12. The bearing device according to claim 1 , wherein the spring is a compression spring.

13. The bearing device according to claim 12 , wherein the compression spring is selected from a compression coil spring, a coiled wave spring, and a wave washer.

14. A hard disk drive device comprising:
the bearing device described in claim 1 ;
a swing arm swingably supported by the bearing device and configured to move a magnetic head on a magnetic disk; and
a base plate to which the shaft member of the bearing device is fixed.

15. The hard disk drive device according to claim 14 , wherein a step portion protruding inward in a radial direction is formed in a central portion of the inner circumferential surface of the outer member,
a through hole into which the bearing device is fitted is provided in a shaft portion of the swing arm,
a screw hole reaching the through hole is provided in the shaft portion of the swing arm,
in a state where the bearing device is fitted into the through hole of the swing arm, a screw is threaded into the screw hole and tightened to attach the swing arm to the bearing device,
a tip of the screw contacts with the bearing device, and
a contact position of the screw with the bearing device is the step portion.

16. A method for producing a bearing device including a shaft member rotatably held inside an outer member having a tubular shape via a first bearing, a second bearing, a third bearing, and a fourth bearing, the method comprising:
inserting the third bearing into the outer member to adhere an outer ring of the third bearing to an inner circumferential surface of the outer member;
inserting a spring into the outer member to bring an end surface of the spring into contact with an inner ring of the third bearing directly or via a washer;
inserting the second bearing into the outer member, pressing an inner ring of the second bearing against the spring, and adhering an outer ring of the second bearing to the inner circumferential surface of the outer member;
inserting the first bearing into the outer member and adhering an outer ring of the first bearing to the inner circumferential surface of the outer member;
adhering an inner ring of the fourth bearing to an outer circumferential surface of the shaft member; and
inserting the shaft member into the inner rings of the first to third bearings, adhering an outer ring of the fourth bearing to the inner circumferential surface of the outer member, and adhering the inner ring of the first bearing to the outer circumferential surface of the shaft member.

17. A method for producing a bearing device including a shaft member rotatably held inside an outer member having a tubular shape via a first bearing, a second bearing, a third bearing, and a fourth bearing, the method comprising:
inserting the third bearing into the outer member to adhere an outer ring of the third bearing to an inner circumferential surface of the outer member;
inserting a spring into the outer member to bring an end surface of the spring into contact with an inner ring of the third bearing directly or via a washer;
inserting the second bearing into the outer member, pressing an inner ring of the second bearing against the spring, and adhering an outer ring of the second bearing to the inner circumferential surface of the outer member;
adhering an inner ring of the fourth bearing to an outer circumferential surface of the shaft member;
inserting the shaft member into the inner rings of the second bearing and the third bearing, adhering an outer ring of the fourth bearing to the inner circumferential surface of the outer member; and
inserting the first bearing into the outer member and onto the shaft member, adhering an outer ring of the first bearing to the inner circumferential surface of the outer member and adhering the inner ring of the first bearing to the outer circumferential surface of the shaft member.

18. The method for producing a bearing device according to claim 16 , further comprising:
adhering at least one of the inner rings of the second bearing and the third bearing to the outer circumferential surface of the shaft member with an elastic adhesive.

19. The method for producing a bearing device according to claim 17 , further comprising:
adhering at least one of the inner rings of the second bearing and the third bearing to the outer circumferential surface of the shaft member with an elastic adhesive.

Assignees

• Minebea Mitsumi Inc

Inventors

• Tsuchiya Kunihiro

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

• F16C19/54 Primary

  Systems consisting of a plurality of bearings with rolling friction (spindle bearings F16C35/08) · CPC title

• F16C25/083

  with resilient means acting axially on a race ring to preload the bearing · CPC title

• F16C2370/12

  Hard disk drives or the like · CPC title

• G11B5/4806 Primary

  specially adapted for disk drive assemblies, e.g. assembly prior to operation, hard or flexible disk drives (G11B5/488 - G11B5/54 take precedence) · CPC title