| 摘要 |
PURPOSE:To prevent a suction valve or an exhaust valve from being pushed up by a lash adjuster and consequently prevent blow bye and noise from developing by a structure wherein the fulcrum of a rocker arm is composed of a lever, the inclination angle of which is adjustable, and the back surface, which is made into a specified form, of the rocker arm. CONSTITUTION:The rocking fulcrum S of a rocker arm 2 is composed of a lever 5, the one end of which is supported by a lash adjuster 7 and the other end of which by a control cam 8. By pivoting the control cam 8, the inclination angle of the lever 5 is controlled, resulting in changing a valve lift. The back surface 10 of the rocker arm 2 is made of the inner envelope of a group of curves made by the supporting surface 11 of the lever 5, when the lever 5 is moved from a position, where the maximum lift is obtained, to a position where the minimum lift is obtained, under the condition that the total length of the lash adjuster 7 is kept constant in the co-ordinate system, in which the rocker arm 2 stands still. Consequently, no pushing up of a valve by the lash adjuster 7 occurs, when the lift is changed and the noise and blow bye are prevented from developing. |
