A New Approach to Increase the Thrust Force of Tubular Linear Voice Coil Motor

In recent years, design studies of tubular linear voice coil motors for linear movement have been increasing. This is because the motor has performance criteria, such as high thrust force, high thrust density, and low thrust ripple. Therefore, different motor models and magnetic modeling have been studied. In these studies, especially the solutions that increase the air-gap magnetic flux density were emphasized. One of the most striking of these motor models is surely the end-iron-free structure. In this study, a single-layer (SL) (two-magnet) end-iron-free structure from a reference study was examined. A double-layer (DL) end-iron-free structure that has higher thrust force in the same motor volume, magnet volume, and parameters was proposed. An analytical approach is first developed, and then, a verification based on finite element analysis was performed. As a result of comparison with the reference study, the proposed motor provided a 10.5% increase in the thrust force and a 9.1% decrease in the thrust ripple. In addition, a design approach developed offers a practical and useful analogy between the DL and the SL.