Ntn Corporation

Kohei Mizuta

Chikara Ohki

A first step of setting a steel material heated to a temperature not lower than an Atransformation point on a forming table and a second step of punching a ring-form member from the steel material and thereafter forming and quenching the ring-form member on the forming table are included. A press die is constructed to be dividable into an inner cylinder and an outer cylinder. In the second step, the ring-form member is punched from a coil material by pressing a tip end portion of the inner cylinder and a tip end portion of the outer cylinder against the coil material. The punched ring-form member is formed and quenched by further pressing a tip end of the inner cylinder against the ring-form member while the ring-form member is held between the outer cylinder and a forming die.

Method of manufacturing rolling bearing ring

A method of manufacturing a rolling bearing ring includes preparing a coil material and a press machine for obtaining a rolling bearing ring from the coil material, setting the coil material on the press machine, and obtaining the rolling bearing ring by heating the coil material on the press machine to a temperature not lower than an Atransformation point, thereafter punching a part of the coil material into a ring form, and thereafter quenching a formed object on the press machine.

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Kuwana, Japan

Kohei Mizuta