| 摘要 |
PROBLEM TO BE SOLVED: To surely close a valve, simplify a flow control circuit, and reduce the number of solenoid valves by converting rotation of a stepping motor into vertical movement, connecting a plunger to a vertical converting means, and opening/closing a valve seat by a valve element formed on the plunger. SOLUTION: When a motor 10 is rotated in the direction where an operating coma 13 is moved downward, a plunger 17 is moved downward. On the other hand, the motor 10 is rotated in the opposite direction, the operating coma 13 is moved in the raising direction. In the case where the plunger 17 is vertically moved, a fluid from a flow-in passage 7d is entered into a clearance between the plunger 17 and a supporting body 14 through a clearance between a guide pipe 16 and the plunger 17. Since an opening area by an operating rod 15 penetrated onto the supporting body 14 is nearly same as an opening area by a valve seat 7h vertical force applied on the plunger 17 by the fluid is balanced. It is thus possible to reduce driving force of a motor, it is possible to downsize a motor 10, and it is possible to manufacture a product which is light, compact, and at a low cost.
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