| 摘要 |
PROBLEM TO BE SOLVED: To provide an actuator with a feed screw mechanism, having less power consumption. SOLUTION: A valve lift control device 2 controls a valve lift amount depending on the axial position of a control shaft. The actuator 10 for linearly driving the control shaft in the axial direction comprises the feed screw mechanism 21, a motor 24, and a holding permanent magnet 110. The feed screw mechanism 21 consists of a rotating shaft 40 to be rotationally driven by the motor 24, and a screw stem 41 connected to the control shaft. The motor 24 consists of a rotor 80 connected to the rotating shaft 40 and having a magnetizing permanent magnet 84, and a stator 82 having a stator coil 91, the rotor 80 being rotated together with the rotating shaft 40 while receiving a rotating magnetic field from the stator coil 91. The holding permanent magnet 110 is mounted on the stator 82. In the state of holding the valve lift amount constant, the rotor 80 is held at a predetermined angle by attractive force between the magnetizing permanent magnet 84 and the holding permanent magnet 110. COPYRIGHT: (C)2008,JPO&INPIT
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