A flow control valve, comprising a frame case (2) having a gas inlet (1a) and a gas outlet (1b), an operating shaft (4) disposed so as to be allowed to move close to and away from the inlet (1a), and an orifice packing (3) installed at the tip of the operating shaft and opening and closing the inlet (1a), wherein two permanent magnets (5a, 5b) are installed on the operating shaft (4) through a yoke (22a) in the state where the same electrodes thereof are opposed to each other and three electromagnetic coils (6a, 6b, 6c) are disposed on the outside of the permanent magnets (5a, 5b) in the state where the winding directions of the coils positioned adjacent to each other are reverse to each other and, when a current flows through the electromagnetic coils (6a, 6b, 6c), electromagnetic forces generated by the electromagnetic coils (6a, 6b, 6c) and the permanent magnets (5a, 5b) are combined with each other, the operating shaft (4) is moved leftward by the combination thrust as shown in the figure so that the orifice packing (3) closes the inlet (1a), whereby the flow control valve of small size with less power consumption and less mal-function can be provided by effectively utilizing the thrust by the electromagnetic force while the structure thereof is simple. |