| 摘要 |
PURPOSE:To prevent the surging of a spring in the whole operation range of an engine by increasing the installation load of a return spring for a suction or exhaust valve, as the engine revolution speed increases. CONSTITUTION:A suction valve 7 or exhaust valve is urged in the closing direc tion by a return spring 10 whose one edge is supported by a hydraulic piston 22. A portion of the lubricating oil supplied from an oil pump 28 is supplied onto the undersurface of the hydraulic piston 22 through a pipe 25 and a check valve 26. Since the pressure of the lubricating oil increases as an engine is set into the high speed revolution, the piston 22 rises against the spring 10, and the installation load of the spring is increased. Therefore, generation of surging in the valve system is prevented over the whole operation range ranging from the low speed revolution to the high speed revolution of the engine.
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