| 摘要 |
The present invention is provided with: a control shaft (60) connected to a control subject (as one example, a variable valve mechanism of an engine (E)); an electric motor (73) that rotates the control shaft via a worm gear mechanism (72); a stopper (80) disposed over the operational trajectory of a worm wheel (74); an angle sensor (94) that can detect the angle of rotation of the control shaft (60); and a controller (90). The stopper (80) has a spring member (for example, a torsion coil spring (84)) that can elastically deform in the direction of operation of the worm wheel (74). The controller (90) drives the electric motor (73) in a manner so that the worm wheel (74) moves towards the stopper (80), and records as a baseline angle (?0) the angle of rotation at the point in time that the rate of change (?) of the angle (?) of rotation detected by the angle sensor (94) falls below a predetermined threshold (?1). As a result, it is possible to precisely detect the baseline angle of angular control of the control shaft. |
