| 摘要 |
PURPOSE:To prevent partial wear of an apex seal caused by thermal deformation of that portion, by forming softening areas with hardness smaller than that of the apex seal on the hard layer at the periphery of plug hole openings. CONSTITUTION:Softening areas X composed of softening layer 15 with hardness smaller than that of an apex seal are formed on the hard chromium plating layer at the vicinity of respective plug hole openings 12a, 13a in the inner circumference 2a of a rotor housing, respectively. The softening layer 15 is formed by the heat treatment effected by irradiating high energy beam with excellent convergence to the hard chromium plating layer 14. With this arrangement, the decline of a gas sealing property due to partial wear of the apex seal caused by thermal deformation of the circumference of the lug hole openings 12a, 13a can be prevented in advance without sacrificing the wear resistance of the inner circumference 2a of the rotor housing on which the hard chromium layer is formed. |
