| 摘要 |
PURPOSE:To aim at improvement in accuracy of the position control of a valve member by oppositely acting the rotational powers caused by a first spring, which acts to return the one-way movement of the valve member, and a second spring, which acts to return the one-way rotation of a rotational transmitting member, on a motor shaft. CONSTITUTION:A displacement member 15 is provided in such a way as to be fitted in contact at a contact point Y with the outer peripheral surface of a roller member 7, in order to produce the rotational power in the direction of an arrow F when it receives the elastic force of a first spring 4 exerting on a valve member 3. A rotation transmitting member 17 integrally rotates with an output shaft 10 because of the engagement with a pin member 16 only when the output shaft 10 rotates counterclockwise. The rotational transmitting member 17 produces the rotational power when the elastic force of a second spring 20 is exerted through a piston member 19. In the rotational power on a motor shaft 11 caused by the elastic forces of the respective springs wherein the rotational power of the second spring 20 is greater than that of the first spring 4.
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