Abstract

To address the issue of fatigue failure in conventional coil springs applied in automotive suspensions, a design method for a permanent magnet eddy current damper (PMECD) is proposed. Firstly, the working principle of the proposed method is introduced, and its dynamic model is established to identify the key parameters that affect its primary performance. Subsequently, numerical models for repulsive force and eddy current damping force are established. Simulation results show that the system has the characteristics of axial and radial symmetry, and the magnetic yoke and copper sleeve reduce magnetic leakage, thereby verifying the rationality of the structural design of the proposed method. The thicker the permanent magnet, the greater the magnetic force produced, and there exists a nonlinear relationship between the magnetic force and displacement. In comparison, the magnetic force generated increases with the thickness of the copper sleeve, exhibiting a trend of first increasing and then decreasing. With the increase in the air gap, its impact on the magnetic force presents a variation trend of first decreasing, then increasing, and finally decreasing again. Although the increase in speed leads to little change in the magnetic force, the eddy current damping force gradually increases, which in turn results in an increase in solid losses. Test results show that the differences between theoretical and simulation calculations and experimental results are less than 5%, which verifies the correctness of the method; compared with the eddy current damper without a copper sleeve, the equivalent damping ratio of the eddy current damper with a copper sleeve increases by 103.7%. This study provides a theoretical basis for the future design and optimization of PMECDs.

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