| 主权项 |
1. A stepping motor motorized valve comprising;
a valve main body having a valve chamber and a valve port opening to the valve chamber, a valve body disposed movably up and down in the valve chamber for opening and closing the valve port, said valve body being driven by a stepping motor, the stepping motor comprising a stator and a rotor rotationally driven by the stator, the valve body being attached to the rotor, a detection rotor attached to the rotor for detecting a rotation position of the rotor, wherein the detection rotor is rotatably disposed on a co-axial center with the rotor, and rotationally driven by the rotor via a rotation drive mechanism provided between the rotor and the detection rotor, and wherein the rotation drive mechanism has a drive play angle in a rotation direction of the rotor to such an extent as to allow the detection rotor to be moved in a direction opposite to the rotation direction of the rotor, when the detection rotor is rotated by the rotor; a conversion mechanism for converting rotational movement of the rotor of the stepping motor to the up and down movement of the valve body, and a rotation stop mechanism for stopping the rotation of the rotor in one direction, when the rotor is rotated by the stator in said one direction and the valve body is moved up and down by the conversion mechanism to reach a predetermined position, wherein said angle of the drive play is defined to be equal to or greater than an angle to which the rotor is attracted in a direction opposite to said one direction due to change in magnetic pole of the stator by a subsequent drive pulse signal, when rotation of the rotor in said one direction is stopped by the rotation stop mechanism. |
