PURPOSE: To reduce the weight of a piston by shaping a ring groove by the lower end of the periphery of an upper piston and the upper end of the periphery of a lower piston for fitting a seal member.
CONSTITUTION: An upper piston 24 with a piston crown part 27 is fitted to a piston pin 35 by foot parts 30 and 31 projected downward from the piston crown part 27 and provided with holes 28 and 29, while a lower piston 25 with a periphery part 34 projected upward is fitted to the piston pin 35 by a pin boss part 33 provided with a piston pin hole 32 positioned on the same axis of the holes 28 and 29. The first ring groove 38 is provided on the crown part 27, on whose lower end a ring-shaped projection 39 is provided to be projected downward. The projection 39 is combined with a ring-shaped projection 42 projected upward from the upper end of the periphery 34 of the lower piston 25 for shaping a ring groove 38, in which a seal member 44 is fitted.
| JP4597997 | How to make a piston for an internal combustion engine |
| WO/1992/005355 | LIGHT-ALLOY PLUNGER PISTON FOR SPARK-IGNITION ENGINES |
| JPH0427745 | PISTON FOR ENGINE |
USHIMURA MASAHARU
NISHIMURA TOSHIFUMI
