| 摘要 |
A piston has a one-piece, preferably cast aluminum, piston head with a cooling oil gallery completely surrounded by and within the head. The piston head has a pin bore for a piston pin that does not intersect with the cooling oil gallery. The pin bore is sized to maintain a substantially uniform clearance between the piston pin and the piston head. The piston head has a passage extending from the pin bore to the cooling oil gallery to allow cooling oil from the gallery to lubricate the piston pin. The passage is preferably drilled after the piston head is cast. Preferably, the pin bore does not have a recess at the passage. A method of manufacturing a piston includes casting the one-piece piston head and drilling a passage from the pin bore to the cooling oil gallery.
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