To provide a torque motor which can be assembled easily and has a smooth flat torque characteristic.
Outer peripheral circular arcs 42b and 43b of permanent magnets 42 and 43 are made off-centered from a rotor core 41 by a distance (d) and the thicknesses of the magnets 42 and 43 become larger towards both ends in the peripheral direction. The peripheral thicknesses of the magnets 42 and 43 and the eccentricities of the circular arcs 42b and 43b from the rotor core 41 are set so as to satisfy the relation, B1=B3=B2cosθ, where B1, B2, and B3 respectively represent the magnetic flux density in the radial direction at the central parts of the arcs 42b and 43b in the peripheral direction, the magnetic flux densities at the positions on the arcs 42b and 43b, in the direction of magnetization forming an angle θ with the center 60 of the rotor core 41 and the centers of the arcs 42b and 43b in the peripheral direction, and the magnetic flux densities in the radial direction at the positions on the arcs 42b and 43b in the peripheral direction which forms the angle θ with the central parts of the arcs 42b and 43b in the peripheral direction.
KAJITA YUKINOBU
TANIMURA HIROSHI
SAKASHITA HIDEYUKI
SHINETSU CHEMICAL CO