JPS57151261A - Linear motor - Google Patents

Abstract

PURPOSE:To reduce the weight and the size of a magnetic circuit for a linear motor and to average the power constant of the motor by shortening the segment width of a permanent magnet segment of the magnetic circuit, dividing the moving coil per one phase, and winding the divided coils in opposite direction of winding at every winding zone. CONSTITUTION:A permanent magnet segments 10 magnetized in a thicknesswise direction are disposed so that the direction of the pole varies at every segment, and are bonded fixedly to an outside yoke 11. Two outside yokes 11 fixed with the segments are disposed at both sides of a central yoke 12 so that the same type of poles of the segments 10 are faced. Since the magnetic flux 17 becomes excessively dense at the center and outside yokes 12, 11 proportionally to the segment width of the segments 10, the segment width of the segments 10 is finely formed, and the thicknesses of the center and outside yokes 12, 11 are reduced. A hollow bobbin 13 is inserted into the central yoke 12 is movable longitudinally without contacting with the segments 10 or the central yoke 13, and a segment plate 14 is secured at 1/2 pitch of the segment width of the permanent magnet at the bobbin 13.