Ball bearing

Patent metadata

Field	Value
Publication number	US-11898604-B2
Application number	US-202117383584-A
Country	US
Kind code	B2
Filing date	Jul 23, 2021
Priority date	Jun 25, 2019
Publication date	Feb 13, 2024
Grant date	Feb 13, 2024

Abstract

A ball bearing includes an inner ring; an outer ring placed outside of the inner ring; a plurality of rolling bodies intervening between the inner ring and the outer ring; and an annular cage including pockets rotatably holding the rolling bodies in a circumferential direction at intervals determining a rotation axis to be a center. The cage comprises a resin composition comprising a polyetherketone-based resin, graphite, and a carbon fiber. The resin composition comprises the polyetherketone-based resin in an amount of 60% by weight or more and 80% by weight or less, the graphite in an amount of 10% by weight or more and 30% by weight or less, and the carbon fiber in an amount of 5% by weight or more and 20% by weight or less when the entire resin composition is determined to be 100% by weight.

First claim

What is claimed is:

1. A ball bearing comprising:
an inner ring;
an outer ring placed outside of the inner ring;
a plurality of rolling bodies intervening between the inner ring and the outer ring; and
an annular cage having a rotation axis, the cage including pockets rotatably holding the rolling bodies in a circumferential direction at intervals, wherein
the cage comprises a resin composition comprising a polyetherketone-based resin, graphite, and a carbon fiber;
the resin composition comprises the polyetherketone-based resin in an amount of 60% by weight or more and 80% by weight or less, the graphite in an amount of 10% by weight or more and 30% by weight or less, and the carbon fiber in an amount of 5% by weight or more and 20% by weight or less when the entire resin composition is determined to be 100% by weight; and
an area ratio is defined by a ratio of an area occupied by graphite having a diameter of a circle to which a particle internally contacts of 30 μm or more relative to a total area occupied by the graphite,
wherein the area ratio is 10% to 20%.

2. The ball bearing according to claim 1 , wherein the polyether ketone-based resin has a melting point of 370° C. or more and a glass transition point of 150° C. or more.

3. The ball bearing according to claim 1 , wherein the polyetherketone-based resin comprises polyetheretherketone.

4. The ball bearing according to claim 1 , wherein the polyetherketone-based resin comprises a copolymer containing a structure unit represented by a following formula (1) and a structure unit represented by a following formula (2):

5. The ball bearing according to claim 4 , wherein 50 mol% or more of the structure unit represented by the above formula (2) is contained in 100 mol% of the structure units constituting the copolymer.

6. The ball bearing according to claim 5 , wherein the copolymer has a melting point of 370° C. or more and a glass transition point of 150° C. or more.

7. The ball bearing according to claim 1 , wherein the carbon fiber is oriented in a direction corresponding to the axial direction in the cage.

Assignees

• Minebea Mitsumi Inc

Inventors

• Karaki Tadahiko
• Tohyama Hirotaka
• Matsumoto Kunihiro

Classifications

• F16C33/44 Primary

  Selection of substances (F16C33/40, F16C33/41 take precedence) · CPC title

• C08K7/06

  Elements · CPC title

• C08L71/00

  Compositions of polyethers obtained by reactions forming an ether link in the main chain (of polyacetals C08L59/00; of epoxy resins C08L63/00; of polythioether-ethers C08L81/02; of polyether-sulfones C08L81/06); Compositions of derivatives of such polymers · CPC title

• F16C33/3856

  made from plastic, e.g. injection moulded window cages · CPC title

• F16C33/416 Primary

  made from plastic, e.g. injection moulded comb cages · CPC title