Variable valve e.g. intake valve, mechanism for e.g. V-type six cylinder internal combustion engine, has moving unit moved to and held at intermediate position between stop positions when actuation mechanism fails to control shaft turning

摘要

The mechanism (100) has stopper structures to stop an axial movement of a moving unit e.g. ball nut unit (46), when the unit moves to maximum stop positions in two directions to respectively increase and reduce a valve lift degree. The moving unit is moved to and held at an intermediate position between the stop positions by a biasing force produced by combining the biasing force of a biasing unit e.g. coil spring (61), and a load applied to a control shaft (32) in a direction to reduce the degree, when an actuation mechanism (6) fails to operate to control turning of the shaft.