Abstract
High-speed and high-precision hydraulic valves are required in industry. The authors have developed a linear servo valve (LSV) with a linear dc motor (LDM). This paper describes methods for designing the magnetic circuit, and for optimizing the mechanical time constant, of a moving-magnet-type LDM. The following results were obtained:
(1) The expression for the mechanical time constant of the LDM is derived by using the permeance analysis method. The proposed stucture of the LDM, which has a minimum mechanical time constant, is obtained by using the permeance analysis method and the finite element method (FEM).
(2) The static thrust of the LDM is calculated also by the permeance analysis method and the FEM. The calculated values of the thrust constant are 61.3 N/A and 62.8 N/A, respectively. The measured value of the thrust constant is 60.7 N/A.
(3) The measured and calculated values of the mechanical time constant obtained by the permeance analysis method, and the values calculated by the FEM, are 1.7 ms, 1.6 ms, and 1.5 ms, respectively.
