| 摘要 |
PROBLEM TO BE SOLVED: To reduce a heat load of a piston by contriving a piston cooling structure in an engine having the pent roof-shaped piston. SOLUTION: Oil passages 12b, 12b are formed on an inlet side and exhaust side of piston pin holes 12a, 12a provided in pin boss parts 12, 12 of the piston 1 to extend in a barrel axis direction of the piston 1. Each oil passage 12b communicates with an annular cooling channel 11f formed inside the piston 1 and extends into a ridge portion 11a of a crown part 11 lying above the pin boss part 12. The oil passage 12b is opened in an inner peripheral surface of the piston pin hole 12a to communicate with the piston pin hole 12a. COPYRIGHT: (C)2008,JPO&INPIT
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