A linear de motor (LDM) with an excellent high-speed response was designed and studied by magnetic field analysis using the finite element method (FEM). In a thin type of determined LDM, the thickness of the yoke on a unipolar- type LDM was selected according to the magnetic saturation. In a multipolar-type LDM, on the other hand, the magnetic flux density in the gap could be increased, and in this case the magnetic attraction force also increased. The thickness of the yoke was therefore selected according to the mechanical strength of the yoke in relation to the magnetic attraction. Thus, the yoke of a LDM was assumed to be a simple beam which a uniform by distributed load was applied. The limit of the LDM thickness was calculated from the bend of the yoke. For a stroke of 112 [mm], the LDM was designed to have a yoke with a thickness of 5.7 [mm] and permanent magnet with a thickness of 1.2 [mm].
