| 摘要 |
PURPOSE:To keep the needle valve under a no-load condition at all times by a method wherein the length of an arm, which is formed between a rotating shaft and a contact point of a wire, is made long at a position whereat a force in the opening direction of the valve becomes large and the same is made short at a position whereat the force in the same direction becomes small. CONSTITUTION:The variable radius arm 14 is formed into the shape of a cam plate, in which the rotating radius thereof is changed continuously. The rotating radius, connecting the contact point P1 of the wire and a rotating center O, becomes the maximum value R1 at the fully closed position of the needle valve 3 while the contact point with the second connecting wire 16 moves on a route shown by the points P2, P3 in accordance with the movement to open the needle valve 3. Then the rotating radius decreases gradually as shown by the signs R2, R3 and the rotating radius R6 becomes the minimum valve at the fully opened position of the needle valve 3. According to this method, the needle valve may be kept under no-load condition substantially. |
