| 摘要 |
PURPOSE:To easily form an annular cooling passage with high precision, by a method wherein a piston crown in constituted such that the piston crown is divided by 2 crossing planes of an annular surface, extending from the mounting part side of its base end to an internal annular cooling passage, and a plane running from an outer peripheral part to the passage. CONSTITUTION:A piston crown 1 is provided at its base end side with a mounting part 2 to a piston, at the forward end side with a top part 3, and at the interior with an annular cooling passage 4. In which case, the piston crown 1 is constituted in a manner that it is divided into 2 division bodies 7 and 8 by means of 2 surfaces 5 and 6 crossing each other at the internal part of the annular passage 4. The one surface forms the annular surface 5 leading from the mounting part 2 side to the annular cooling passage 4, and the other surface forms the plane 6 extending from the outer peripheral part of the piston crown 1 to the annular cooling passage 4. Thereafter, joining of the division bodies 7 and 8 by are weld manufactures the piston crown 1. |
