VARIABLE VALVE TIMING MECHANISM

摘要

A drive mechanism is described for transmitting driving torque from the crankshaft to a camshaft of an internal combustion engine. The mechanism incorporates means for permitting a limited degree of rotation of one of the shafts relative to the other and comprises concentric drive and driven members (14, 10) connected respectively to the crankshaft and the camshaft. At least one lever (20) is pivotably supported on one of the members (10) and has a force transmitting surface that is biassed by a spring (22) to remain in contact at all times with a reaction surface (24) on the other member. The position of the point of contact between the two surfaces is dependent upon the relative angular position of the drive and driven members (14, 10) and moves progressively to vary the mechanical advantage of the lever as the shafts rotate relative to one another under the action of the torque reversals on the camshaft (12).