Design and Analysis of Discrete Halbach Magnetic Lead Screws Using Nonskewed PMs

Abstract

A magnetic lead screw (MLS) is a device that uses the magnetic field of permanent magnets (PMs) to convert between translational and rotational motions while achieving a gearing action. The gearing action indicates that the device can convert between a high-speed, low-torque rotational motion and a low-speed, high-force translational motion, making it ideal for various applications, including vehicle active suspension systems. This article proposes a new MLS configuration based on discrete Halbach PMs. In comparison to previous designs, the proposed configuration simplifies manufacturing using nonskewed, arc-shaped PMs. However, the proposed configuration introduces harmonics in the torque and force waveforms. This article presents a detailed analysis that explores the impact of varying the number of segments of the proposed discrete Halbach MLS, as well as the PM thickness, radial, and axial PM lengths while maintaining the same lead. A design procedure is presented to balance the system’s complexity with the harmonic contents in the torque and force resulting from the discretization of the PMs. The design and analysis were carried out using 3-D finite element analysis (FEA), and an experimental prototype was constructed to validate the design.