JPS56157251A - Motor - Google Patents

Abstract

PURPOSE:To enable the suppression of the occurrence of an iron loss irrespective of the material of the armature core of a motor and to prevent the pulsation of the rotating torque of the rotor of the motor by forming a structure that the armature core and the rotor are integrally rotated and the relative position between the core and the rotor does not vary. CONSTITUTION:A cylindrical armature core 14 is so formed as to be disposed concentrically with field poles 9 from a rotor yoke 7 and to be integrally risen and is disposed within the air gap 11d of a bobbin 11. Eight valleys 14a are formed on the outer peripheral surfce of the core 11, extend elevationally, eight edges 14b are confronted with the magnetic neutral point 9a among the magnetic poles 9, the width of the air gap 15 is thus circumferentially altered, and is minimized at the neutral point 9a. Thus, the magnetic flux density at the gap 15 can be varied in trapezoidal wavy shape and can be maintained constantly regardless of the rotating position of the rotor 4. A driving circuit 18 then energizes the armature coil 13, thereby producing a torque between the coil 13 and the magnetic poles 9 and rotating the rotor 4 in a predetermined direction.