Patent ID: 7056247

Claim:
A pulley unit comprising: a pulley; a shaft body concentrically disposed inside of an inner diametrical surface of said pulley and in a relatively rotatable relationship with said pulley; a one-way clutch interposed in an annular space between the inner diametrical surface of said pulley and an outer diametrical surface of said shaft body; at least one rolling bearing disposed in said annular space, said at least one rolling bearing including a roller bearing on at least axially one side of said one-way clutch; and seal rings disposed on each of axially one end and axially other end of said annular space for sealing said annular space; said inner diametrical surface of said pulley forming an outer ring raceway of each of said one-way clutch and said roller bearing; said outer diametrical surface of said shaft body forming an inner ring raceway of each of said one-way clutch and said roller bearing; said one-way clutch and said roller bearing each including a plurality of rollers interposed between said outer ring raceway and the inner ring raceway in the circumferential direction, and a retainer having a plurality of pockets each accommodating said rollers one each; said retainer of said roller bearing having an annular portion facing to a side of a first seal ring of said seal rings, an outer cylindrical circumferential surface extending axially inward from said annular portion and having a first retainer diameter, a second retainer diameter greater than said first retainer diameter, and at least one radially planar surface extending from said outer cylindrical circumferential surface to said second retainer diameter thereby defining a step between said annular portion and said second retainer diameter, so as to increase a storage volume for lubricating oil between said roller bearing and said first seal ring; and said inner diametrical surface of said pulley between said one-way clutch and a given one of said at least one rolling bearing being provided with a recess which increases said storage volume for the lubricating oil in said annular space.