Abstract: With reference to the result of research and experiments done at home and abroad since 1972, in particular our own achievement in research since 1977, this article promotes a rational and practical scheme for the construction of large scale cycloid Bearings and additionally presents a modification method for tooth profile on cycloid disk of a cycloid speed reducer using common techniques that will obtain a novel and ideal tooth profile .Thus, it could not only totally avoid the scoring of the teeth, but also would considerably increase the transmitting power and the life of the bearing of the rotational arm bearings without increasing the radial size.

Key words: 摆线针轮行星传动, 齿形, 结构设计