Patent ID: 7004861

Claim:
A pulley unit comprising: a hollow shaft; an outer ring member disposed concentrically about said hollow shaft and defining an annular space therebetween; a one-way clutch interposed in said annular space between said hollow shaft and said outer ring member; a ball bearing disposed in said annular space at one side of said one-way clutch; and a roller bearing disposed in said annular space at another side of said one-way clutch; wherein: said hollow shaft is formed as an inner ring of each of said one-way clutch, said ball bearing and said roller bearing, said hollow shaft has a first outer surface region formed as the inner ring of said ball bearing, said first outer surface region having an inner raceway shaped as a groove in said first outer surface region in which balls of said ball bearing roll and a shoulder having a first diameter, said hollow shaft has a second outer surface region formed as said inner ring of said one-way clutch having cam surfaces, a second diameter corresponding to an inner diameter of said cam surfaces, and an inter-cam surface diameter, defined by inter-cam surface regions circumferentially interposed between said cam surfaces, which is greater than said second diameter, said hollow shaft has a third outer surface region formed as said inner ring of said roller bearing, said third outer surface region having a third diameter corresponding to a diameter of an inner raceway of said roller bearing, said first diameter is greater than said second diameter, and said second diameter is not less than said third diameter, and said inter-cam surface diameter is substantially equal to said first diameter of said shoulder of said ball bearing, said second diameter is substantially equal to said third diameter of said inner ring of said roller bearing, said hollow shaft is formed by plastic processing and said outer surface of said hollow shaft is cemented and said hollow shaft has a threaded portion on an inner surface of said hollow shaft which is protected from cementation and thereby not cemented; and said first, second and third outer surface regions adjoin one another and no portions of said first, second and third outer surface regions have an increasing radius in a direction from said groove of said first outer surface region to a further area of contact of rollers of the roller bearing of said third outer surface region.