| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a high-frequency hardening method that improves accuracy of a tubular member whose inner surface is subjected to high-frequency hardening through an inner surface mobile hardening. <P>SOLUTION: The high-frequency hardening method includes the steps of: setting a position of one third level of the whole depth level from an opening 3, as a heat input amount switching position P1; setting a first heat input amount in a step (first hardening step) from an opening P0 to the heat input amount switching position P1, as Q1 (Q1>Q0); setting a second heat input amount in a step (second hardening step) from the heat input amount switching position P1 to a deep end P2, as Q2 (Q0>Q2); and setting the first heat input amount Q1 to 3.5-4.0 times of the second heat input amount Q2. Accordingly, an opening level of the opening 3 at a groove width of a roller groove 6 is controlled, thereby securing dimensional tolerance of the groove width of the roller groove 6. <P>COPYRIGHT: (C)2012,JPO&INPIT |
