| 摘要 |
PURPOSE:To ensure prevention of blow by of high pressure gas even when a crevice is generated in dual ringwall boundary ranges, by applying a closing process with plastic working for the crevice in the dual ringwall boundary ranges where a peripheral side of a ring carrier is adjacent to that of a piston itself. CONSTITUTION:Three rollers 30 are set in the upper and lower directions HI that are facing dual ringwall boundary ranges a, b where a peripheral side 11 of a piston itself 10 is adjacent to a peripheral side of a ring carrier 12. At the same time, a rotation axis 28 being rotated, pressure and a plastic working are applied to the dual ringwall boundary ranges a, b, or they were crushed successively by each roller 30 that is pressed and energized in the central direction of the piston, and a closing process is applied to a peripheral end side of a possibilitic part for generation of crevice t in dual ringwall boundary ranges. For the piston manufactured in this way, even when a crevice is generated inside the possibilitic part for generation of crevice t of the dual ringwall facing ranges a, b as time passes by, it is ensured to prevent blow by of high pressure gas round the ring carrier, through the dual ringwall boundary ranges that are correspondent with an entrance and an exit of the crevice, because plastic working and pressure are applied to near the ranges. |
