Abstract：To solve the manufacture problem of helical-shape magnetic poles ( HSMP) in linear-rotary magnetic gear ( LRMG) , a technical scheme of using semi-oblique ring magnetic poles ( SORMP) to replace HSMP was proposed. The static characteristics of three schemes ( both in screw and nut were HSMPs ( G1) , HSMPs in screw and ORMPs in nut ( G2) , and both in screw and nut were SORMP ( G3) ) were simulated with FEM. According to the maximum thrust force and torque, G2 was slightly larger than the half of G1, which was 57. 7%and 53. 9% respectively, and G3 was only 4% and 0. 6% smaller than G1. It was proved that the transmission characteristics of SORMP was almost same as HSMP. In order to describe the relationship of pole width and pitch of SORMP, a concept of pole pitch ratio ( k) was proposed. The static characteristics of LRMG with SORMP were simulated for K = 0 ~ 0. 7, and it was found that when K = 0. 3, the thrust force and torque of unit volume pole had the largest value. To improve the pole utilization rate, it was suggested that K = 0. 3.

Keyword：semi-oblique ring permanent magnet;helical-shape magnetic pole;screw;