Rolling bearings

Abstract

An inexpensive rolling bearing is proposed which can be used stably for a long time where the lubricating conditions are severe or bending stresses act. Inner and outer rings of rolling bearings mounted in a rocker arm of an automobile are made of high-carbon chrome bearing steel. They are subjected to heat treatment in which after carbonitriding, high-temperature tempering is carried out. Then they are induction hardened to impart resistance to material quality change and a compressive stress of not less than 200 MPa to the surface layer, thereby markedly improving the rolling contact fatigue life and the tension-compression fatigue strength while keeping the material cost as before. Thus, this bearing can be used stably for a long time even though it is a full complement type bearing, lubricating conditions tend to worsen and the outer ring is repeatedly subjected to bending stress from the cam.

1 .- 6 . (canceled) 
   
   
       7 . A method of manufacturing a rolling bearing, said method comprising:
 forming the inner and outer rings from a chrome bearing steel, a carburized steel or a carbon steel for mechanical structures;   carbonitriding at least one of an inner ring and an outer ring, followed by oil quenching and then induction hardening the at least one of the inner and outer rings, such that a surface layer of the at least one of the inner and outer rings has a compressive strength of not less than 200 MPa and a tempering hardness at 500° C. of not less than Hv 550; and   mounting a plurality of rolling elements between the inner and outer rings.   
   
   
       8 . The method of manufacturing a rolling bearing in accordance with  claim 7  further comprising
 after said carbonitriding and before said induction hardening, tempering the at least one of the inner and outer rings.   
   
   
       9 . The method of manufacturing a rolling bearing in accordance with  claim 7 , wherein the tempering is carried out at a temperature of 600° C.