Patent ID: 7189171
Filing Date: 2007-03-13
Classification: C21D,C22C,C23C,F16C,F16H

Abstract:
1. A rolling bearing for a belt-driven continuously variable transmission comprising: an outer race having an inner peripheral surface formed with an outer raceway, an inner race having an outer peripheral surface formed with an inner raceway, and a plurality of rolling elements rollably provided between the outer raceway and the inner raceway, the outer race being fitted into and supported by a fixed section, the inner race being fitted onto and supported by a section which rotates together with the pulley of the belt-driven continuously variable transmission, so that the pulley is rotatably supported by the fixed section, the rolling bearing for the belt-driven continuously variable transmission being characterized in that at least the outer race is made from an iron-base alloy material containing C from 0.15 weight % to 0.5 weight %, Si from 0.1 weight % to 1.5 weight %, Mn from 0.1 weight % to 1.5 weight %, and Cr from 0.5 weight % to 3.0 weight %, and undergoing carbonitriding, quenching, tempering process and grinding finish, so that the surface portion of the outer raceway has a surface layer that contains C from 0.8 weight % to 1.2 weight %, and N from 0.05 weight % to 0.50 weight %, wherein the amount of retained austenite at 50 μm under the surface of the outer raceway is from 20 volume % to 45 volume %, and wherein the residual compression stress at 50 μm under the surface of the outer raceway is from 150 MPa to 500 MPa.