Design and Manufacture of a Linear Actuator Based on Magnetic Screw Transmission

This article proposes a practical design guide for a linear electromagnetic actuator based on the concept of magnetic screw transmission, in which manufacturing and assembly technologies are investigated. The surface-inserted design is first used to form a required helical-shape magnetic pole, which exhibits simple processing, high precision, and robust structure. Moreover, different topologies are developed using the 3-D finite-element analysis aided design, with the goal of optimizing thrust force. In addition, different number of permanent-magnet (PM) segments are first proposed to reduce the cogging effect. Afterward, the linear actuator integrates the rotary machine and the magnetic screw together to construct a compact design and decouples the magnetic circuits. The decoupling design focuses on the self-shielding effect of the Halbach PM array, and the special bearing supports are selected to avoid the eccentricity. Finally, a prototype is built using the developed techniques. Experiments are carried out on a linear test bench, verifying the theoretical analysis.