| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To form a continuous and good hardened layer on the whole peripheral surface containing the tooth surface and the back surface of a rack bar as a body to be hardened and on the outer peripheral surface of a shaft part having round shape in the cross-sectional surface continuously extended from the whole peripheral surface containing the above tooth surface and the back surface. <P>SOLUTION: A hardening process, in which the outer peripheral surface of the shaft part 5 in the rack bar 1 is induction-heated and cooled while rotating the rack bar 1 by centering the axis P and relatively shifting along the axis P direction of the rack bar 1, and a hardening process, in which the whole surface containing the tooth surface 3 and the back surface 4 of the rack bar 1, is induction-heated and cooled while relatively shifting the rack bar along the axis P direction under state of holding the rack bar 1 so that a main conductive body disposed along the axis P direction of the rack bar 1 oppositely disposes to each of the tooth surface 3 and the back surface 4 of the rack bar 1 without rotating the axis P of the rack bar 1, are continuously performed without stopping the induction-heating, cooling and the relative shifting in the axis direction of the rack bar. <P>COPYRIGHT: (C)2004,JPO</p> |
