Patent ID: 6121712
Filing Date: 2000-09-19
Classification: H02K

Abstract:
A driving method of a three-phase annular winding cascade claw-pole type stepping motor comprising (1) a rotor consisting of a cylindrical magnet magnetized in the circumferential direction so as to form M pieces of N pole and M pieces S pole alternately, where M is an integer and .gtoreq.2, and (2) a stator having annular three stator units arranged in the axial direction of the rotor concentrically with the rotor axis, each of said stator unit consisting of two opposite stator cores having claw poles extending axially on the inner peripheral surface thereof, and of one of three stator windings of U, V and W phases held between said two stator cores, said windings of U, V and W phases being arranged in this order in the axial direction, said claw poles being separated by 180.degree./M from one another and magnetized by said stator winding in opposite polarities alternately, said three stator windings being connected to form a star or delta connection, adjacent claw poles magnetized by the stator windings of U phase and V phase are deviated by 60.degree./M from each other in the circumferential direction, and adjacent claw poles magnetized by the stator windings of V phase and W phase are deviated by 60.degree./M from each other in the circumferential direction, said annular stator windings being excited so that a magnetic flux generated by the annular stator windings of one phase in the axial direction becomes always opposite to that by annular stator windings of the other phase, in case of two phase exciting driving.