| 摘要 |
[Problem] To provide a method for reliably manufacturing a hollow poppet valve containing a refrigerant, with which the cooling effect of the umbrella part can be achieved effectively. [Solution] A valve manufacturing method equipped with: a step wherein a hollow part (S) that opens to the outside and extends from an umbrella part (14) to a shaft part (12) is formed within a valve main body, at the shaft-end part of which the umbrella part (14) is integrally formed; a step wherein a refrigerant and an inert gas are introduced into the hollow part (S) from the aperture part; a step wherein the aperture part is sealed with a separate member (18); and a step wherein the valve main body (W2), in which the refrigerant and the inert gas have been sealed in the hollow part (S), undergoes heat treatment in a heat treatment furnace (40). In the heat treatment step, the valve main body (W) undergoes heat treatment with the umbrella part (14) oriented downward. During the heat treatment the refrigerant (a solid) melts and moves downward within the hollow part (S) toward the umbrella part (14), and when the refrigerant cools down and solidifies it remains in the location to which it has moved. In all of the manufactured valve products the location where the refrigerant (solid) is loaded is a fixed location on the umbrella part (14) side, so the cooling effect of the umbrella part (14) can be achieved effectively. |
