Hitachi Powdered Metals Co., Ltd.

Nissan Motor Company Limited

Honda Giken Kogyo Kabushiki Kaisha

Jyun-ichi Yamada

Kei Ishii

Tadayuki Tsutsui

Yutaka Mabuchi

Takashi Murata

Akira Fujiki

Yukihiro Maekawa

Akira Fujiwara

Tomoaki Arakawa

Yuji Yamanishi

Ryoji Sato

Disclosed is a sintered gear composed of a sintered alloy having a metal matrix and pores. The tooth surface () of the tooth and the bottom land () have a densified layer () in which the porosity is reduced to 10% or less from the sintered alloy. The densified layer at the tooth surface is formed with a thickness of 300 to 1,000 microns, and the densified layer at the bottom land is formed with a thickness of 10 to 300 microns. The boundary surface of the densified layer is continuous from the tooth surface side to the bottom land side so as not to have a substantial level difference.

Sintered gear

A sintered sprocket for a silent chain is obtained from a material with few addition elements by a simple densifying method. The sintered sprocket is made of an ferrous material having an ovarall composition containing Cu at 1 to 2%, C at 0.5 to 0.8%, Mn as an inevitable impurity at 0.10% or less, and balance of Fe and other inevitable impurities by mass and has a density of 7.1 Mg/mor higher, 65 HRA or higher as a hardness in the gear teeth, and a martensite, sorbite, bainite, or their mixed structure as a cross-sectional microscopic structure in at least the gear teeth and the peripheral area of the gear teeth.

Sintered sprocket for silent chain and production method therefor

A sintered sprocket has a high overall density and excellent contact pressure resistance. The sprocket is produced from a sintered alloy selected from the following alloys ((1) to (3)), is densified to have a relative density of 95% or higher in the surface layer of the gear teeth by forming by rolling, having a surface hardness of 700 HV or higher, and is useful for a crankshaft, a cam shaft, a balancer shaft, or a water pump shaft of an internal combustion engine:

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Matsudo, Japan

Jyun-ichi Yamada