| 摘要 |
PROBLEM TO BE SOLVED: To uniformize the surface temperature of a core pin by suppressing the stagnation in the flow of a cooling medium. SOLUTION: The core pin 1 molding a linear-less cylinder bore has a hollow structure, and a cooling tube 3 is insertedly arranged at the inside thereof. The central part of the cooling tube 3 is provided with an internal cooling water passage 31, and spiral grooves 33 are formed at the inner circumferential face of the core pin 1 confronted with the outer circumferential face of the cooling tube 3 so as to be a spiral cooling water passage 35. Cooling water is fed from the internal cooling water passage 31 in the cooling tube 3 and cools the core pin 1 when being made to flow through the radial cooling water passage 35. COPYRIGHT: (C)2010,JPO&INPIT |
