SCREW PUMP AND START POSITION SETTING METHOD OF SCREW PUMP

摘要

PROBLEM TO BE SOLVED: To provide a screw pump capable of preventing or suppressing fracture of an inner rotor even when a device is miniaturized, and making an outer rotor smoothly rotated while following up the inner rotor.SOLUTION: A screw pump 1 is a screw pump in which an outer rotor 30 is corotated and driven at a rotation angle of 1/2 of an inner rotor 40, and includes an inner rotor driving portion 45 for rotating and driving the inner rotor 40, an outer rotor driving portion 35 for rotating and driving the outer rotor 30, and a controller 60 for controlling two driving portions 35, 45. The controller 60 auxiliarily drives the outer rotor driving portion 35 by a rotation control signal to have a rotational frequency of 1/2 of a rotational frequency of the inner rotor 40, and an output control signal to drive with rotational resistance of the outer rotor 30 or more and summed resistance obtained by adding frictional resistance between the rotors and viscosity resistance received by the outer rotor 30 to the rotational resistance of the outer rotor or less, on the basis of driving information of the inner rotor driving portion 45.SELECTED DRAWING: Figure 1