摘要 |
<p>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.</p> |