A method for manufacturing a gear which effectively prevent a crack from occurring inside a tooth part when rolling processing is performed on a teeth part of a gear raw material is achieved. A method according to one embodiment for manufacturing a gear by performing rolling processing on a tooth part of a sintered gear raw material. The method includes, when the rolling processing is performed on the tooth part of the gear raw material, pressing the gear raw material toward a center of rotation of the gear raw material by a rolling machine and, when at least the rolling processing is performed on the tooth part of the gear raw material toward a center of a thickness thereof by a pressing machine, pressing a region where an internal density of the tooth part of the gear raw material decreases.

A method for manufacturing a gear which effectively prevent a crack from occurring inside a tooth part when rolling processing is performed on a teeth part of a gear raw material is achieved. A method according to one embodiment for manufacturing a gear by performing rolling processing on a tooth part of a sintered gear raw material. The method includes, when the rolling processing is performed on the tooth part of the gear raw material, pressing the gear raw material toward a center of rotation of the gear raw material by a rolling machine and, when at least the rolling processing is performed on the tooth part of the gear raw material toward a center of a thickness thereof by a pressing machine, pressing a region where an internal density of the tooth part of the gear raw material decreases.

A method for manufacturing a rolling bearing unit is provided to periodically reciprocate a stage (38) in a vertical direction by rotating and driving a servo motor (44) while rotating a roll about a central axis of a hub main body using a roll driving motor (43) in a state in which a processing surface of the roll is pressed against other end surface of a caulking section in an axial direction. A period of the reciprocation is restricted by a relation between a rotation position of the roll about the central axis of the hub main body and an engaged state between concave sections, which are sections between a plurality of processed teeth formed in the processing surface of the roll, and a face spline tooth formed by the concave section.

A method for manufacturing a rolling bearing unit is provided to periodically reciprocate a stage (38) in a vertical direction by rotating and driving a servo motor (44) while rotating a roll about a central axis of a hub main body using a roll driving motor (43) in a state in which a processing surface of the roll is pressed against other end surface of a caulking section in an axial direction. A period of the reciprocation is restricted by a relation between a rotation position of the roll about the central axis of the hub main body and an engaged state between concave sections, which are sections between a plurality of processed teeth formed in the processing surface of the roll, and a face spline tooth formed by the concave section.

A method and a system for producing a ring-shaped member. A punching process is carried out on an axial intermediate part of a first intermediate annular material so as to produce a pair of ring-shaped members. A punching step includes a step in which a first punching process is carried out over a first range of the axial intermediate part in the circumferential direction, and a step in which a second punching process is carried out over a second range of the axially-oriented intermediate part, which is at least partially different than the first range, in the circumferential direction. The first punching process is carried out such that at least one tab is formed. The second punching process is carried out such that at least one separate tab is formed, thereby producing the pair of ring-shaped members.

A method and a system for producing a ring-shaped member. A punching process is carried out on an axial intermediate part of a first intermediate annular material so as to produce a pair of ring-shaped members. A punching step includes a step in which a first punching process is carried out over a first range of the axial intermediate part in the circumferential direction, and a step in which a second punching process is carried out over a second range of the axially-oriented intermediate part, which is at least partially different than the first range, in the circumferential direction. The first punching process is carried out such that at least one tab is formed. The second punching process is carried out such that at least one separate tab is formed, thereby producing the pair of ring-shaped members.

The forging apparatus includes: a fixed punch 21 in which a tapered part 21a for molding the diameter enlarged part is formed; a die 30 arranged so as to surround an outer periphery of the fixed punch 21; and a movable punch 10 that is arranged above the fixed punch 21 so as to be opposed to the fixed punch 21. The die 30 is floatingly supported and includes a protruding part 33a for molding the groove on an inner peripheral surface thereof, and when the movable punch 10 is lowered, an annular blank 40 set between the fixed punch 21 and the die 30 is pressed, and the annular member is molded, the die 30 is lowered along with the movable punch 10, and the groove is molded on the outer peripheral surface of the diameter enlarged part while molding the diameter enlarged part.

A gear for a torque transmission device includes a gear member and a support member with a weld formed therebetween, and the gear member has a first surface and a second surface. The first surface has teeth. The support member has a support surface. The weld attaches the second surface of the gear member and the support surface. Portions of the second surface of the gear member and the support surface which contact the weld are ungrooved.

A gear for a torque transmission device includes a gear member and a support member with a weld formed therebetween, and the gear member has a first surface and a second surface. The first surface has teeth. The support member has a support surface. The weld attaches the second surface of the gear member and the support surface. Portions of the second surface of the gear member and the support surface which contact the weld are ungrooved.

A rotary press device (33) includes a restriction section (36) configured to restrict a motion of a roll (30) around a central axis of a roll (30) against movement of the roll (30) around a central axis of a hub main body (8) during rotary forging. In an example, the restriction section (36) has guide teeth (44) meshed with teeth formed on a processing surface of the roll (30).