对新型电动自行车的关键动力部件———直流无刷电机作了深入的剖析与设计。本文所介绍的电动自行车中使用的直流无刷电机,系参考英国Patscentre 国际实验室协作设计产品,采用全电子操纵系统,电动自行车的最高时速可达25km/ h ,一次充电行程为64km。该电机的功率为350W,重6kg ,具有自充电与过压过流全保护功能,效率可达85 % ,性能综合指标远优于传统的以有刷电机为动力的电动自行车。 关 键 词:位置传感器;无接触换向;气隙磁密 Abstract : This paper intends to make a better design on the D. C. motor , the key part of the new style electric bicycle , after the detailed analysis. The D. C. motor without coal brushes is in a new style , with higher work rate , less wear and tear and lower noise. This kind of motor discussed in this paper , is designed in reference to the product designed by Patscentre International Lab , μK, which is operated with electronic system completely , in the top speed of 25km per hour , covering the distance of 64km each time it’s charged. The motor is 6kg in weight , with the power of 350W, which has the function of self2charge , and complete pro2 tection when the electric current and voltage is over the normal levels in the rate close to 85 %. The comprehensive index of the functions of this kind of motor is much better than that of all the traditional ones with coal brushes. Key words : positional sensor ; exchange of A. C. and D. C. ; the air2space inside and the thickness of magnetic field intensity