JPS5561269A - Commutatorless motor - Google Patents

Abstract

PURPOSE:To accurately detect the speed of a commutator motor without adverse effect of variation of magnetic flux when changing a current by providing separately a rotating speed detecting member at the outer periphery of a rotor drive member. CONSTITUTION:A doughnut-like rotary driving main magnet 3 magnetized with N and S poles alternatively in its thickness direction is fixed to a rotor disk-like yoke 1, and doughnut-like rotating speed detecting sub-magnet 4 magnetized with a number of N and S poles in its thickness direction alternatively is fixed to the outer peripheral collar 1a of the yoke 1. Drive polyphase armature windings W1-W4 are so fixed to the back surface of base plate 7 fixed at predetermined interval from the stator disk-like yoke 5 as to face oppositely with the main magnet 3, and a speed detecting winding 8 formed in print in gear state facing opoositely with the sub-magnet 4 is fixed onto the outer periphery on the surface of the base plate 7. Rotary position detectors HG1, HG2 disposed at different electric angle of pi/2 each other are fixed to the base plate 7 and other sub base plate 7', respectively.