Patent ID: 8424205

Claim:
A manufacturing method for a bearing ring member comprising a cylindrical member having an inner peripheral surface and an outer peripheral surface, a double-row of back-to-back arrangement outer-ring raceways at two locations in an axial direction of the cylindrical member around the inner peripheral surface, and an outward facing flange around the outer peripheral surface, the method comprising: performing an upsetting process to compress a circular column shaped metal raw material in an axial direction thereof to obtain a preliminary stage intermediate member having two ends in an axial direction and a middle section therebetween in the axial direction, the middle section having an outer diameter that is greater than outer diameters of the ends; surrounding the preliminary stage intermediate member with dies having a flange formation space; pressing the preliminary stage intermediate member from both of the ends thereof in the axial direction with punches to plastically deform the preliminary stage intermediate member such that each of the ends in the axial direction are formed into cylindrical sections each having an outer peripheral surface and an inner surface shape that fits an outer surface shape of the punches; and forming the outward facing flange of the bearing ring member with the flange formation space of the dies to obtain a later stage intermediate member; wherein the metal raw material has a volume that is larger than that necessary for forming the later stage intermediate member, the dies comprise a stationary die and a movable die, the stationary die has a tip end surface and is fixed around one of the punches, the movable die has a tip end surface and is located around another of the punches such that it applies an elastic force in a direction toward the stationary die, the tip end surface of the movable die and the tip end surface of the stationary die face each other, and during the pressing step the punches compress the preliminary stage intermediate member from both of the ends thereof in the axial direction thereof causing the metal raw material of the preliminary stage intermediate member to fill into a cavity that is surrounded by the stationary and movable dies and both of the punches, after which the metal raw material presses the movable die causing the movable die to move away from the stationary die against the elastic force such that an extra portion of the metal raw material moves into a space that occurs between the tip end surfaces of the stationary and movable dies.