| 摘要 |
PURPOSE:To provide a flow amount control valve excellent in response characteristics, by using, for example, a pulse motor as a drive source for a spindle through utilizing a thrust exerted on an electric current or a magnetic body placed in a magnetic field. CONSTITUTION:A stator 12 is provided with windings at three poles A, B, C, and when an input is provided in A phase, a rotor 13 is moved to the position indicated by (b). When a pulse input is provided in B phase, the rotor 13 is rotated counterclockwise by 30 deg., and is stopped. When a pulse is inputted into the C-phase winding, the rotor 13 is rotated in the same direction as above by 30 deg., and by repeating these operations, the rotor 13 is maintained at an arbitrary position. The rotor 13 is connected directly to the spindle 10, so that the spindle 10 is moved in the axial direction by the rotation of the rotor 13, and the degree of opening of a nozzle 15 is varied. By sufficiently reducing the pitch angle of a screw 11, reduction ratio of the axial displacement of the spindle 10 to the angle of rotation of the rotor 13 can be enlarged. Accordingly, even when the number of poles of the pulse motor is small, the open area of the nozzle 15 can be varied in a wide range, and a sufficiently high accuracy can be obtained. |
