| 摘要 |
PROBLEM TO BE SOLVED: To solve the problem in a conventional vernier type which makes pitches of small teeth of a rotor unequal to those of a stator so as to reduce cogging torque and current torque distortion of a three-phase hybrid type stepping motor, and in which no sufficient study has not been made on the number of small teeth of 50, thus having not produced so high effect. SOLUTION: This three-phase hybrid type stepping motor is constituted of the stator in which six poles are disposed at an inner periphery of a roughly annular-shaped yoke at equal intervals. A three-phase winding is formed by winding the wire around respective poles with six polar teeth disposed at top ends of the poles. The rotor with two rotor poles having 50 small teeth around the outer periphery at equal pitches are attached at an edge surface of a permanent magnet magnetized to two north and south poles in the axial direction by being displaced by 1/2 pitch of a displacement pitch of the small teeth. In this three-phase hybrid type stepping motor, the rotor is journaled so as to rotate freely and is made to face the stator through a cavity. A permeance distribution of the six polar teeth provided with at the top ends of the stator poles is set at a vernier pitch balanced by sixth or tertiary higher harmonics, and a teeth width ratio is set at 0.35-0.45.
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