| 摘要 |
Provided is a hollow poppet valve for which the heat-drawing effect is improved by providing a stepped part for generating turbulent flow at a prescribed location of a small-diameter hollow part (S2) of the valve shaft part in the axial direction. This hollow poppet valve (10) has an umbrella part (14) integrally formed on one end of a shaft part of the poppet valve, with a hollow part (S) being formed from the umbrella part (14) to the shaft part (12) of the poppet valve, and the hollow part (S) being filled with a cooling material (19). The small-diameter hollow part (S2) within the shaft part (12) communicates with a large-diameter hollow part (S1) inside the umbrella part (14), and the inner diameter of a hollow part (S21) of the small-diameter hollow part, which is closer to the shaft end, is greater than that of a hollow part (S22), which is closer to the umbrella part, thereby providing a stepped part (17) in the small-diameter hollow part (S2), and the coolant material (19) fills the interior past the stepped part (17). When the coolant material (19) moves inside the small-diameter hollow part (S2) in conjunction with the up/down operation of the valve (10), a turbulent flow is generated near the stepped part (17), thereby promoting the stirring of the coolant material (19). |
