| 摘要 |
PROBLEM TO BE SOLVED: To discontinue an automatic closing spring and a position detecting sensor by making a stepping motor switched from a nonenergization state to an energization state execute an operation corresponding to the detection of an initial position, to reduce the driving current of the stepping motor and to miniaturize the stepping motor and moreover, a diaphragm. SOLUTION: The diaphragm is provided with a stepping motor 1 actuated to a fixed actuating position by switching from a nonenergization state to an energization state and diaphragm members 4 and 5 driven in opening/closing directions by the stepping motor and constituted so that when the stepping motor is actuated to the fixed actuating position, the diaphragm members are driven to a reference position (for instance, a fully closed diaphragm position) in the opening/closing directions.
|
