| 摘要 |
PURPOSE:To suppress torque ripple in a three-phase coreless motor by containing higher harmonics in the distribution of the widthwise distance of the magnetizing region of a pole at a field section comprising permanent magnets. CONSTITUTION:A coreless motor comprises a field section 1, air core coils 4, and the like. Assuming the number of pole at a field section 1 is (m), the number of air core coil 4 is (p) and a pair of N and S poles occupy one period T in the rotary angle direction of the motor, the widthwise distance h(theta) of the maguetizing region 1B of the pole can be expressed in term of the rotary angle (theta) by a formula shown on the drawing where the coefficients (an) or (bn) have values not equal to zero for one or more n=i+ or -1. Here, ho=H(0<=theta<pi), ho=-H(pi<theta<=2pi), and negative sign is considered variation of the polarity. When (q) is the greater common measure of m/2 and p, i=p/q. When the number of the pole is 4 and the number of the air core is 3, the profile at the magnetizing region 1B is determined by adding a positive 4th sinusoidal higher harmonic by 10% to a normal profile in the widthwise direction thus achieving torque ripple reduction effect. |
