JPS57206263A - Two phase switching type brushless motor - Google Patents

Abstract

PURPOSE:To contrive to unify the overlappedly current carrying period and to prevent abrupt variation of torque of a two phase switching type brushless motor by a method wherein the non-magnetized or non-saturatedly magnetized regions are provided at the parts being a part of pair of the main poles, and being the parts at the neiggborhood of the prescribed electric angle, and moreover at the parts to correspond with a magnetism sensing position detecting element when magnets are rotating. CONSTITUTION:Nearly rectangular commutating poles 3a, 3b, 3c, 3d, and 3e, 3f constituting respectively a pair of N-S poles are formed respectively between the main poles 2a, 2b, 2c, 2d, and 2e, 2f constituting the electric angle of 360 deg. at both the sides of center lines l in the radial directions at the 180 deg. electrically angular positions, and being in parallel with the lines thereof. Moreover the non- saturatedly magnetized regions 18a-18f having the same shape mutually are formed in the pairs of main poles at the neighboring parts of the electric angles 0 deg. and 360 deg. and moreover to correspond with the Hall element 10 when the rotor magnet 1 is rotating, and the main poles 2a-2f and the commutating poles 3a-3f excluding the non-saturatedly magnetized regions are magnetized saturatedly to the N or S pole.