Study on a Stator Yoke Structure of a Magnetic Screw Motor

Linear actuators mounted on collaborative robots that work in the same space as humans are required to have high thrust density and back drivable characteristics. Therefore, a series elastic actuator with elasticity using a mechanical spring has been proposed, but the problem is that the structure is complicated and the size is increased. Therefore, we proposed a magnetic screw motor that integrates a magnetic screw and a motor, but there was a problem that the thrust was small. This paper describes the influence of a step skew structure in the stator yoke on the motor characteristics. A magnetic screw motor with a spiral stator is proposed. However, it is difficult to achieve the spiral stator in terms on the cost and manufacturing. In order to solve the problem, a step skew structure is proposed, and its torque characteristics are investigated using 3-D finite element analysis.