Pulley unit having one-way clutch
A pulley unit comprises a pulley, a shaft relatively rotatable with the pulley and concentrically arranged inner side of the pulley, a one-way clutch interposed in an annular space between the pulley and the shaft, and a ball bearing arranged adjacent to the one-way clutch in an axial direction in the annular space. The ball bearing has an inner ring and an outer ring. Raceway curvatures of the inner and outer rings of the ball bearing are set to not less than 50.5% and not more than 52.0%.
1. A pulley unit comprising:
a pulley having an inner circumferential surface defining a through hole;
a shaft having an outer circumferential surface and disposed relatively rotatable with said pulley and said shaft being concentrically arranged inside said through hole of said pulley;
a one-way clutch interposed in an annular space between said inner circumferential surface of said pulley and said outer circumferential surface of said shaft said one-way clutch having an inner ring and an outer ring respectively formed by said outer circumferential surface of said shaft and said inner circumferential surface of said pulley;
a ball bearing arranged adjacent to said one-way clutch in art axial direction in said annular space, said ball bearing having an inner ring and an outer ring respectively formed by said outer circumferential surface of said shaft and said inner circumferential surface of said pulley; and
a roller bearing arranged adjacent to said one-way clutch in said axial direction in said annular space, said roller bearing having an inner ring and an outer ring respectively formed by said outer circumferential surface of said shaft and said inner circumferential surface of said pulley;
wherein a radial internal clearance after mounting of said ball bearing is set to less than 20 μm and raceway curvatures of said inner and outer rings of said ball bearing are set to not less than 50.5% and less than 51.0%.
2. The pulley unit according to claim 1 wherein an axial clearance of said ball hearing is in the range of 0–85 μm.