Method for manufacturing a bearing ring member

A manufacturing method for a bearing ring member wherein

• in order to form a bearing ring member having a double-row of back-to-back arrangement outer-ring raceways at two locations in the axial direction around the inner peripheral surface of a cylindrical member, and an outward facing flange around the outer peripheral surface, an upsetting process is performed that compresses a circular column shaped metal raw material in the axial direction to obtain a preliminary stage intermediate member, the outer diameter of the middle section in the axial direction thereof being greater than the outer diameter of both end sections in the axial direction;
• after which with this preliminary stage intermediate member surrounded by dies having a flange formation space for forming an outward facing flange, this preliminary stage intermediate member is pressed from both ends in the axial direction by a pair of punches to plastically deform this preliminary stage intermediate member such that both ends in the axial direction are formed into cylindrical sections having an inner surface shape that fits the outer surface shape of these punches, and forms an outward facing flange around the outer peripheral surface having a shape that fits the flange formation space to obtain a later stage intermediate member;
• wherein a material having a volume that is larger than that necessary for forming this later stage intermediate member is used as the raw material, and dies comprising a stationary die, which is fixed around one of the punches, and a movable die, which is located around the other of the two punches such that it applies an elastic force in the direction toward the stationary die, are used as the dies, where with the tip end surface of the movable die and the tip end surface of the stationary die facing each other, the punches compress the preliminary stage intermediate member from both ends in the axial direction causing the metal material of the preliminary stage intermediate member to fill into a cavity that is surrounded by both of the dies and both of the punches, after which this metal material presses the movable die causing the movable die to move back from the stationary die against the elastic force such that the extra metal material moves into a space that occurs between the tip end surfaces of the dies.