| 摘要 |
PROBLEM TO BE SOLVED: To provide a linear drive device which prevents screws from biting each other in a feed screw mechanism even when an output shaft is driven and suddenly stopped at a movement limit position by an urging member while stopping power supply to a stator. SOLUTION: In a valve element drive unit 1, although the force applied to a rotor 50 is small, the position of an axial direction L is secured because a bearing member 6 is a sliding bearing. Therefore, when the output shaft 8 is driven by a coil spring in the closing direction, and suddenly stopped at the movement limit position while the power supply to the stator 20 is stopped, and when the rotor 50 is moved downward, and rotated by its own inertia, the movement is prevented, but clearances d1, d2 between the bearing member 6 and the rotor 50 is sufficiently wide in the thrust direction. Therefore, the rotor 50 is not prevented from moving downward. The rotational force due to the inertia force of the rotor 50 does not acts as a force causing a male screw 88 and a female screw 58 constituting the feed screw mechanism to bite each other. COPYRIGHT: (C)2010,JPO&INPIT
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