Evaluation of the Thrust Constant of a Linear DC Motor for a Pen Recorder

Pen recorders with moving-coil-type linear dc motors (LDMs) have already been used in practical applications. However, an optimal design has not yet been established within the dimensional limitations of such devices. This paper provides a guideline for optimum design through characteristic analysis of pen recorder units, using a thin, long-stroke LDM. In the LDM, the flux density acting on the coil is equal to the flux density in the gap. The LDM thrust constant consists of N, 1 and B, where N and 1 are known as design values. However, B is determined by the magnetic design. The finite element method (FEM) is used to analyze the three-dimensional magnetic fields of the magnetic circuit, which consists of a permanent magnet and yokes.