Nsk Corporation

Shuji Wada

Kyozaburo Furumura

Kenji Yamamura

Hiroshi Narai

In a rolling bearing in which at least one member of an inner race, outer race and rolling elements is made of an alloy steel containing 0.2 to 1.0 wt % of C, 3.0 to 14.0 wt % of Cr and 0.8 to 3.0 wt % of V, the balance being Fe, the member being carburized or carbonitrided, followed by hardening and tempering to secure that the surface carbon concentration C% and the concentrations Cr%+V% of Cr and V satisfy a relationship of C%.ltoreq.0.13 (Cr%+V%)+1.10 and that carbides existing on a surface of the member have an area fraction of 15 to 50%, the rolling bearing has an extending service life even if it is used under lubrication in the presence of foreign matter and exhibits superior wear resistance to be hard to wear even if there occurs a breakage of oil film.

Rolling bearing with long service life and high wear resistance

An object of this invention is to provide a rolling bearing which is long enough in serve life even when it is applied with a lubricant mixed with foreign matters, simply by quenching or by carbonitriding it for a short period of time, and which can be formed at a relatively low manufacturing cost. A rolling bearing is formed as follows: The quantities of elements such as C, Si, Mn, Cr and Mo forming a bearing alloy steel, and the quantity of retained austenite are adjusted to be in predetermined ranges, and the steel is quenched and tempered or carbonitrided so that its hardness is in the following range:

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Kanagawa, Japan

Shuji Wada