US 11,898,604 B2
Ball bearing
Tadahiko Karaki, Nagano (JP); Hirotaka Tohyama, Nagano (JP); and Kunihiro Matsumoto, Nagano (JP)
Assigned to MINEBEA MITSUMI Inc., Nagano (JP)
Filed by MINEBEA MITSUMI Inc., Nagano (JP)
Filed on Jul. 23, 2021, as Appl. No. 17/383,584.
Application 17/383,584 is a continuation in part of application No. PCT/JP2020/023138, filed on Jun. 12, 2020.
Claims priority of application No. 2019-117325 (JP), filed on Jun. 25, 2019.
Prior Publication US 2021/0348649 A1, Nov. 11, 2021
Int. Cl. F16C 33/44 (2006.01); F16C 33/38 (2006.01); F16C 33/41 (2006.01); F16C 19/06 (2006.01); C08L 71/00 (2006.01); C08K 7/06 (2006.01); F16C 19/16 (2006.01)
CPC F16C 33/44 (2013.01) [C08K 7/06 (2013.01); C08L 71/00 (2013.01); F16C 33/3856 (2013.01); F16C 33/416 (2013.01); F16C 19/06 (2013.01); F16C 19/16 (2013.01); F16C 2208/02 (2013.01); F16C 2208/36 (2013.01); F16C 2316/13 (2013.01)] 7 Claims
OG exemplary drawing
 
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%.