Ntn Corporation

Noriyoshi Yoshizuka

Fuminori Satoji

Yousuke Sugai

Toshihiko Mouri

Yoshinobu Akamatsu

Kazuyoshi Harimoto

Provided is a sintered bearing () including an inner layer () and an outer layer () formed by integral molding, the sintered bearing () having a bearing surface (A) formed on an inner peripheral surface () of an inner layer (). The inner layer () is made of sintered metal containing Fe and a hardness increasing element (such as Ni or Mo). The outer layer () is made of sintered metal containing Fe and no hardness increasing element. A concentration gradient of the hardness increasing element is present at an interface between the inner layer () and the outer layer ().

Sintered bearing

A rolling member which has improved strength and permits stable formation of oil films between its rolling surface and its mating surface and which shows a long life even under unfavorable lubricating conditions. The surface of the rolling member is subjected to heat treatment while nitriding. The rolling member is then treated to form minute recesses in its surface so that such surface has a surface roughness parameter RMS of not less than 0.10 .mu.m and a negative SK value. Thus, the surface strength of the rolling element increases and the oil film forming rate improves. The surface of the rolling member is less likely to suffer peeling damage and wear. Its life is prolonged.

Growing community of inventors

Aichi, Japan

Noriyoshi Yoshizuka