| 摘要 |
PURPOSE:To reduce the inertial mass of a rocker arm, by constituting a rocker arm with two sections, and by enabling the rocker arm to be rested in association with the axial shift of a selector member, and by forming one of the arm sections with a material having a low specific weight. CONSTITUTION:In an arrangement in which two intake valves disposed in each engine cylinder C are operated by two rocker arms 10, 12 while one exhaust valve is operated by a rocker arm 14, the rocker arm 10 for one of the intake valves, is composed of a first arm 24 which abuts against the front end of a valve stem and is made of S45C or the like, and a second arm 28 which abuts against a cam shaft and is made of aluminum or the like. A plunger 32 urged by a spring is fitted onto the first arm 24, and fits the small diameter section 40b of a lock-off plate 38 onto the small diameter section 32b of the plunger 32 to lock the arm 24 at the projecting extremity of the plunger 32 so that the intake valve is set in the operating condition. The above-mentioned plate 38 is integrally incorporated with a selector member 42 which is driven by hydraulic pressure fed into a hydraulic chamber 45. |
