OUTSIDE SCREW TYPE HIGH EFFICIENT OPENING AND CLOSING DEVICE OF ROTARY RESISTANCE TYPE

摘要

PROBLEM TO BE SOLVED: To obtain larger thrust force than thrust force generated owing to rotation resistance between a female screw and a male screw by rotating the male screw which is screw-fitted in the female screw without using the female screw by the same force and open and close a valve element by the thrust force. ;SOLUTION: This is an opening and closing device which opens and closes a valve element by moving a valve rod screw 2 in the axial direction. A pinion 4 which rotates integrally with an input shaft 3 is provided, and a bevel gear 5 which meshes with the pinion 4 and rotates around the shaft core of the valve rod screw 2 is fitted in play in the valve rod screw 2. A free rotating gear 6 in the shape of male screw which meshes with the valve rod screw 2 and rotates around the shaft core which is parallel with the valve rod screw 2 is attached on the bevel gear 5 in such a manner that it can rotate freely. The free rotating gear 6 is turned around the valve rod screw 2 in accordance with the rotation of the bevel gear 5, and the valve rod screw 2 advances and retracts and is driven by thrust force generated due to rotation resistance of the valve rod screw 2 and the free rotating gear 6.;COPYRIGHT: (C)1997,JPO