| 摘要 |
PURPOSE:To obtain a good airtight characteristic by a method wherein chamferings for the edges of abutting surfaces between the protruded section and the recessed section of the outer periphery of the ring at the joining part thereof are made unnecessary in the piston ring having double angle joining part construction. CONSTITUTION:The protruded part 5 protruding into the peripheral direction of the piston ring is provided at the corner part 2 of the outer peripheral surface 3 nearer to the side surface 4 of one of the joining edge part while the recessed part 7 receiving the protruded part 5 is provided on the other joining edge part 6 at a position opposing to said protruded part 5. Subsequently, the joining parts are closed under a condition that an electrical insulating thin plate 11 such as 4-ethylene fluoride resin, for example, or the like is interposed between the abutting surface of the protruded part 5 and the recessed part 7, and a chrome plating treated layer 12 is formed on the outer peripheral surface 3. Thereafter, the thin plate 11 is removed and a finishing work is applied to the outer peripheral surface 3, if necessary, to complete the piston ring A. According to this method, chamfering for the joining part is not necessitated and the airtight characteristic may be improved. |
