| 摘要 |
PURPOSE:To make both valve timing and valve lift variable by arranging a hydraulic pivot at an end of a swing arm for driving an exhaust/suction valve to make an oil hole position of a hydraulic chamber variable and to make a plunger at an end of the swing arm slidable within the hydraulic chamber. CONSTITUTION:A plunger 2 for supporting an end 1 of a swing arm 6 for opening/closing a suction/exhaust valve is made slidable within a plunger body 4 and is supported by being pressed always with a spring 8. The plunger body 4 is provided at its upper side part with a hole communicating with an oil passage 7 and its bottom is supported with an adjustment cam 3. When the valve opening timing is to be advanced and the valve lift is to be increased, the cam 3 is turned to move the plunger body 4 upward, which causes the plunger 2 to close the hole of the plunger body 4 immediately when a swing arm 6 is depressed with a cam 5 so that the plunger 2 serves as a hydraulic pivot to open the suction/exhaust valve immediately.
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