Bearing with magnetic fluid seal

Patent metadata

Field	Value
Publication number	US-9611893-B2
Application number	US-201615332655-A
Country	US
Kind code	B2
Filing date	Oct 24, 2016
Priority date	Apr 26, 2012
Publication date	Apr 4, 2017
Grant date	Apr 4, 2017

Abstract

Provided is a bearing with a magnetic fluid seal reliably maintaining sealing of a rolling element section in the bearing and having a structure ensuring high productivity. In a bearing with a magnetic fluid seal according to the present invention, a plurality of rolling elements 7 are disposed between an inner ring and an outer ring, and a ring-shaped magnet is arranged at an opening side of the inner and outer rings so as to retain magnetic fluid, so that the plurality of rolling elements are sealed. The magnet is magnetized so that magnetic poles are oriented in an axial direction. A ring-shaped pole plate is arranged to be in contact with an outer side surface of the magnet in the axial direction. Outer-ring-side magnetic fluid is retained between the outer ring and the magnet, and inner-ring-side magnetic fluid is retained between the inner ring and the pole plate.

First claim

What is claimed is:

1. A bearing comprising:
an inner ring;
an outer ring;
a plurality of rolling elements positioned between the inner ring and the outer ring;
a ring-shaped magnet positioned between the inner ring and the outer ring at an axially outer side of the plurality of rolling elements and magnetized such that magnetic poles are oriented in an axial direction;
a pole plate arranged so as to be in contact with an axially outer side surface of the ring-shaped magnet, the pole plate having substantially a same shape as the magnet; and
inner-ring-side magnetic fluid retained in a gap formed between an outer peripheral surface of the inner ring and the pole plate,
wherein a step is formed in an inner peripheral surface of the outer ring such that a distance between the inner and outer rings is greater at an axially outer side than at an axially inner side,
the ring-shaped magnet is attached to a step surface of the step by a magnetic force, and
an axially outer side surface of the pole plate is retreated such that at least an inner-ring-side end thereof is axially inside an axially outer side surface of the inner ring.

2. The bearing of claim 1 further comprising outer-ring-side magnetic fluid retained between the outer ring and the pole plate and/or between the outer ring and the magnet.

3. The bearing of claim 2 wherein the outer-ring-side magnetic fluid is arranged between the outer ring and an axially inner side surface of the ring-shaped magnet.

4. The bearing of claim 2 , wherein a gap is formed between an outer peripheral surface of the pole plate and an inner peripheral surface of the outer ring, and the outer-ring-side magnetic fluid is further disposed in the gap.

5. The bearing of claim 1 wherein the pole plate is formed of a magnetic material.

6. The bearing of claim 1 , wherein the ring-shaped magnet is bonded to the pole plate.

7. The bearing of claim 1 further comprising a ring-shaped shield provided on the axially outer side surface of the pole plate.

8. The bearing of claim 1 further comprising a spacer provided between the magnet and the outer ring.

9. The bearing of claim 8 wherein the spacer is formed of a magnetic member.

10. A bearing comprising:
an inner ring;
an outer ring;
a plurality of rolling elements positioned between the inner ring and the outer ring;
a ring-shaped magnet positioned between the inner ring and the outer ring at an axially outer side of the plurality of rolling elements and magnetized such that magnetic poles are oriented in an axial direction;
a pole plate arranged so as to be in contact with an axially outer side surface of the ring-shaped magnet, the pole plate having substantially a same shape as the magnet; and
outer-ring-side magnetic fluid retained in a gap formed between an inner peripheral surface of the outer ring and the pole plate,
wherein a step is formed in an outer peripheral surface of the inner ring such that a distance between the inner and outer rings is greater at an axially outer side than at an axially inner side,
the ring-shaped magnet is attached to a step surface of the step by a magnetic force, and
an axially outer side surface of the pole plate is retreated such that at least an outer-ring-side end thereof is axially inside an axially outer side surface of the outer ring.

11. The bearing of claim 10 further comprising inner-ring-side magnetic fluid retained between the inner ring and the pole plate and/or between the inner ring and the magnet.

12. The bearing of claim 11 wherein the inner-ring-side magnetic fluid is arranged between the inner ring and an axially inner side surface of the ring-shaped magnet.

13. The bearing of claim 11 , wherein a gap is formed between an inner peripheral surface of the pole plate and an outer peripheral surface of the inner ring, and the inner-ring-side magnetic fluid is further disposed in the gap.

14. The bearing of claim 10 wherein the pole plate is formed of a magnetic material.

15. The bearing of claim 10 , wherein the ring-shaped magnet is bonded to the pole plate.

16. The bearing of claim 10 further comprising a ring-shaped shield provided on the axially outer side surface of the pole plate.

17. The bearing of claim 10 further comprising a spacer provided between the magnet and the inner ring.

18. The bearing of claim 17 wherein the spacer is formed of a magnetic member.

Assignees

• Globeride Inc

Inventors

• Ohara Takeshige

Classifications

• F16J15/43

  kept in sealing position by magnetic force · CPC title

• F16C33/7889

  mounted to an inner race and extending toward the outer race · CPC title

• F16C33/7846

  with a gap between the annular disc and the inner race · CPC title

• F16C33/765 Primary

  by a magnetic field · CPC title

• F16C19/06

  with a single row or balls · CPC title