There are many problems in traditional reducers, such as large volume, high quality, low efficiency and high noise when the transmission ratio is large. In order to meet the needs of industry development, engineers and technicians have done a lot of research on the reducer, and put forward a variety of new reducer design schemes. Liang Xichang et al.  divided the existing reducers into high transmission ratio reducers, high power density reducers, high precision reducers, low noise reducers, super power reducers, micro reducers, quality limited reducers, etc., and pointed out the development direction of new reducers. At the same time, researchers have also carried out research on various new reducers, and achieved fruitful research results, providing technical support for the design of circular arc tooth line cylindrical gear reducer.
Circular arc tooth line cylindrical gear has the characteristics of large coincidence, high bearing capacity, high efficiency, long service life, high stability, low noise, no axial force, etc., which can make up for the shortcomings of, and herringbone gear transmission, and is widely concerned by researchers . The original concept of circular arc tooth line cylindrical gear was first proposed by Yoshiro Hasegawa of Japan. Later, Tseng R T and Tsay C B et al. Used the vector method to study the arc tooth line cylindrical gear, deduced its mathematical model, and analyzed the contact characteristics of the gear; Di Yutao discussed the meshing interference, axis parallelism error, center distance and meshing performance of the arc tooth line cylindrical gear; Peng Fuhua  proposed to use the circular drawing method to process the curve gear, The machining efficiency has been greatly improved, but it is difficult to be popularized due to the high cost. Linziguang  applied the curved cylindrical gear to the gear oil pump to solve the problem of oil trapped in the straight gear oil pump. Song Aiping studied the meshing mechanism and characteristics of the circular arc tooth line cylindrical gear, and analyzed and compared the advantages and disadvantages of various common gear machining methods; Alfonso FA proves that the circular arc tooth line cylindrical gear transmission has certain superiority by comparing the contact stress and transmission error of spur gear, helical gear and circular arc tooth line cylindrical gear transmission.
Although scholars have carried out theoretical analysis on the meshing characteristics, bearing capacity and machining methods of circular arc tooth line circular arc gear, no large-scale application has been found, because:
(1) The tooth profile of the gear is not uniform, and the selection standard of the design parameters of the gear is not established;
(2) There is no systematic study on the contact characteristics of gears;
(3) The inspection method, parameters and standards of gear have not been established;
(4) The bench test of circular arc curve cylindrical gear transmission pair has not been carried out.
Therefore, it is proposed to apply the circular arc tooth line cylindrical gear to the transmission system of the reducer, and analyze and compare the transmission performance of the circular arc tooth line cylindrical gear reducer and the involute cylindrical gear reducer.
According to the structural design parameters of zqa50 involute circular arc gear reducer, this paper designs the structure of circular arc tooth line cylindrical gear reducer, and establishes the three-dimensional model of circular arc tooth line cylindrical gear and zqa50 reducer by using UG nx8.0. The program of circular arc tooth line cylindrical gear is compiled by using UG / open grip language, and the circular arc tooth line cylindrical gear is cut by the movement between the rack and the blank, After the treatment of the tooth surface knife mark, the final modeling is completed; the main transmission structure of the reducer is analyzed by the finite element method, and the advantages and disadvantages of the contact performance of the two reducer are compared and analyzed.
The results show that the contact area of the circular arc tooth line cylindrical gear is near the middle section of the tooth width, and there are many meshing contact tooth surfaces, that is, the degree of involution is large; the maximum contact stress of the circular arc tooth line cylindrical gear is smaller than that of the traditional gear, when the same torque is transmitted, the structure of the circular arc tooth line cylindrical gear is more compact; the stress on the shaft meets the strength requirements.
Generally speaking, the transmission performance of circular arc gear is superior to that of transmission gear. The research results can provide relevant basis for the production and manufacture of circular arc tooth line cylindrical gear reducer.