| 摘要 |
PURPOSE:To eliminate the need for drilling, press fitting of guides, centering, etc. after casting, by forming a supporting pin which regulates the normal position relation of a valve guide and a valve seat integrally to a core in the stage of casting cylinder heads. CONSTITUTION:A valve guide 9 is inserted onto the stem-shaped part 3 of a supporting pin 2 for casting and a valve seat 10 is fitted onto a valve shaped part 5 in order to constitute a core 15 for casting of cylinder heads. The parts 3, 5 are formed into one body by a coupling part 4 in such a way that the normal position relation of the guide 9 and the seat 10 is regulated. The part 4 has a function of coupling and supporting a sand mold core 14 for the purpose of forming the intake and exhaust passages to be provided in a cylinder head. Such core 15 is positioned and assembled by a mechanism 31 in casting molds 38 consisting of a top mold 20, a right mold 21, a bottom mold 22, and a bottom mold core 23, and a fixing device 24 is advanced to the cavity 37 side; at the same time, the casting molds are clamped. The inside of the cavity 37 formed in such a way is packed and cast with molten metal, and after the casting, the pin 2 is removed, whereby the casting is obtained. |
