Ntn Corporation

Taichiro Furukawa

Atsushi Yamashita

Tadayoshi Yoshioka

Masanori Ichikawa

Kyouzi Maeda

Kohhei Kondoh

Yukio Hashimoto

Shingo Mizoguchi

Seiji Kanbori

A carburization and quenching apparatus includes: a plurality of carburizing chambers for carburizing thin plate parts; a gas cooling chamber for cooling the thin plate parts carburized in the carburizing chambers; and a reservoir tank 3 connected to the gas cooling chamber for delivering a cooling gas into the gas cooling chamber. The plurality of carburizing chambers are positioned at an approximately equal distance from the gas cooling chamber to surround the gas cooling chamber. In a continuous furnace, thin plate parts can be transported successively at least between a carburizing chamber and a pressurized cooling chamber. The thin plate parts are carburized in the carburizing chamber and then rapidly quenched in the pressurized cooling chamber by cooling the thin plate parts with a pressurized gas which can be e.g. inert gas.

Carburization and quenching apparatus

A retainer and method of manufacturing the same which makes it possible to form roller stopper lugs reliably on broken surfaces on the side faces of the crossbars formed by punching and also guide surfaces which can guide rollers with high accuracy. A plurality of protrusions are formed on both sides of the crossbars. The surfaces of the protrusions are ironed in both thickness directions to form roller stopper lugs at both ends of the protrusions. The flat surfaces formed on the protrusions by ironing serve as the roller guide surfaces. Thus, the rising and sinking amount of the rollers can be controlled with high accuracy.

Retainer for roller bearing and method for manufacturing the same

The present invention is intended to dispense with the post-processing of the pocket guide surfaces while securing the precision thereof, to improve the precision of the cage and to reduce the manufacturing cost. A cage (1) according to the present invention is formed such that the inner wall surfaces of the thin-walled and thick-walled portions (1a) and (1b) are continuous with each other through taper surfaces (1d) inclined toward the centers and the guide surfaces (1c1) of the pocket (1e) are shearing surfaces q on the pitch circle PCD.

Cage for needle roller bearings and method of producing same

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Hamamatsu, Japan

Taichiro Furukawa