| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a cage for a needle roller bearing and the needle roller bearing capable of securing the durability without increasing the cost. <P>SOLUTION: In this cage 12 for the needle roller bearing composed of a pair of annular parts 12a and a plurality of pillar parts 12b connecting the annular parts 12a, the pillar parts 12b are formed by shearing and punching an iron plate material having carbon concentration of 0.08-0.3%. As the hardness of the base of at least the pillar parts 12b after processing is increased in comparison with that before the processing, by work hardening in shearing and punching work, the fatigue strength can be improved. On the other hand, by processing a material of the cage 12 under a temperature lower than A<SB>1</SB>transformation point excluding a case of welding processing, for example, the grain boundary oxidation occurring during high-temperature processing such as quenching processing is inhibited, and the cracking of the pillar parts 12b and the like can be prevented. <P>COPYRIGHT: (C)2004,JPO&NCIPI |
