| 摘要 |
PURPOSE:To harden a cam surface over its whole width, by selecting a heat input amount which is well suited for treatment in that the center part of the cam surface is fused again and hardened along the direction of its peripheral edge over the range of practically 2/3-3/4 the whole width of the cam surface by a high-density energy source and simultaneously, the other part of the cam surface is brought to a martensite transformation by a heat influence caused due to a re-fusing treatment and is hardened. CONSTITUTION:If a heat input amount for re-fusing a cam surface 3 of a cam shaft 1 by means of a high-density energy source increases, the range of a heat- influnced part round a re-fused part 14 increases, but conversely, a range 15, being hardened by a martensite transformation, sometimes decreases. The re- fusing width of the cam surface is needed to be set to more than substantially 2/3 the whole width of the cam surface. In order that both edges of the cam surface are hardened by bringing them into a martensite transformation occasioned by the heat influence of the input heat, and shoulder sagging and fusing are prevented from occurring to both ends of the cam, it is desirable that the maximum value of the re-fusing width of the cam surface is set to substantially less than 3/4 the whole width of the cam surface. |
