| 摘要 |
PURPOSE:To provide optimum operative and inoperative conditions of valves by providing an arm drivably engaging at a predetermined time according to the running condition of an engine with another arm normally driven by a rocker arm contacting slidably a cam for driving intake and exhaust valves. CONSTITUTION:A rocker arm 4 for opening and closing a valve is supported on one end by a hydraulic lash adjuster 8, bears on the other end against the upper end of valve shaft and is driven on the back of intermediate portion by a cam 3. The cam 3 has on the intermediate portion a projecting surface 3b both sides of which are provided with cylindrical surfaces 3a respectively. The intermediate portion 6a of the rocker arm 1 is opposed to the projecting surface 3b of the cam 3. One end of the intermediate portion 6a is supported by a spring 26 and the other end disengageably engages the side edge 4a of the rocker arm through a pin 12. The pin 12 can be slided by a hydraulic piston 16 so that the hydraulic piston 16 is operated according to the running condition of an engine to provide the engagement and disengagement of the intermediate portion for providing the operative and inoperative conditions of valves.
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