To provide a piston capable of reducing deviation of surface pressure of each skirt part with respect to a cylinder wall face and reducing friction by reducing a surface pressure load.
This piston 1 made of an aluminum alloy includes a crown part 7 defining a combustion chamber, a pair of arc-shaped skirt parts 8, 9 on a thrust side and the opposite side thereof provided integrally with the crown part 7 and sliding on the cylinder wall face 3, and a pair of curved apron parts 11, 12 connected to both side ends in the circumferential direction of each skirt part 8, 9 via connection portions 10 and having pin bosses 13, 14. Recesses 19, 20 are formed in upper end portions of the apron parts 11, 12 and constricted parts 11d and 12d are formed in lower portions of the recesses 19 and 20, rigidity of at least a part on the crown part 7 side in each skirt part 8, 9 is lowered, and strong abutting contact with the cylinder wall on the crown part 7 side is suppressed to reduce friction.
SUE SEIICHI
KONO KEISUKE
| JPH0392544U | 1991-09-20 | |||
| JPH0389958U | 1991-09-12 | |||
| JPS6392867U | 1988-06-15 |