Steel ball rolling configuration and constant velocity universal joint
AssigneeNtn Corporation
InventorsYoshimasa Ushioda, Hiroki Ooe, Kazuhiro Muramatsu
Life of this patent
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Abstract
A steel ball rolling configuration and a constant velocity universal joint have a superior oil retention effect between a surface of a steel ball and a partner rolling surface, and can form a thick oil film, improve lubrication, and extend life of the steel ball. The constant velocity universal joint includes a rolling surface and a steel ball that is lubricated by grease and rolls over the rolling surface. A surface roughness of the steel ball is roughened to become more similar to a surface roughness of a partner rolling surface. Numerous miniscule recesses roughly tens of micrometers in size are randomly disposed on the surface of the steel ball.
Claims3
A steel ball rolling configuration comprising:
- a rolling surface;
- and
- a steel ball that is lubricated by grease and rolls over the rolling surface, wherein
- a surface of the steel ball has numerous miniscule recesses roughly tens of micrometers in size randomly disposed therein, and
- a surface roughness of the surface of the steel ball, except for the numerous miniscule recesses, is similar to a surface roughness parameter of the rolling surface and larger than 0.4 μmRa.
A constant velocity universal joint comprising:
- an outer joint component having an inner diameter surface on which track grooves are formed;
- an inner joint component having an outer diameter surface on which track grooves are formed;
- a plurality of steel balls interposed between the track grooves on the outer joint component and the track grooves on the inner joint component that transmit torque;
- and
- a cage interposed between the inner diameter surface of the outer joint component and the outer diameter surface of the inner joint component that holds the steel balls, wherein
- a surface of each of the steel balls has numerous miniscule recesses roughly tens of micrometers in size randomly disposed therein, and
- a surface roughness of the surface of each the steel balls, except for the numerous miniscule recesses, is similar to a surface roughness parameter of the track grooves of the outer joint component and the track grooves of the inner joint component and larger than 0.4 μmRa.
A constant velocity universal joint comprising:
- an outer joint component having an inner diameter surface on which a track groove is formed;
- an inner joint component having an outer diameter surface on which a track groove is formed;
- a steel ball interposed between the track groove on the outer joint component and the track groove on the inner joint component that transmits torque;
- and
- a cage interposed between the inner diameter surface of the outer joint component and the outer diameter surface of the inner joint component that holds the steel ball, wherein
- a surface of the steel ball has numerous miniscule recesses roughly tens of micrometers in size randomly disposed therein, and
- a surface roughness of the surface of the steel ball, except for the numerous miniscule recesses, is similar to a surface roughness parameter of the track groove of the outer joint component and the track groove of the inner joint component and larger than 0.4 μmRa.
Dependencies are inferred from the claim text.