Design of a Coaxially Magnetic-Geared Linear Actuator for Electric Power Steering System Applications

摘要

This paper will present the designs and feasibility assessments of a linear electromagnetic actuator for providing the required power steering forces directly [1]. A systematic scheme for designing the coaxially magnetic-geared linear actuator will be established and the specifications of electric power steering (EPS) system for an economy-sized vehicle will be adopted to the system structural designs. Within the physical and operational constraints, the device is coaxially composed by a tubular linear PM motor and a tubular magnetic gears set as conceptually shown in Fig. 1. Determinations of the optimized geometrical compositions of the motor and the gears set based on the fluxes and thrust forces that can be conveyed will be assessed in detail. By considering the vehicle operational speeds, the corresponding dynamic performances of the proposed EPS system, as illustrated in Fig. 2, and the resulting radii of turning circles are also evaluated. It is thus confirmed that the adoptions of such electromagnetic systems for those common EPS systems in the vehicles are technically feasible.