Nutation reducer is a new type of transmission based on the principle of gyroscopic motion. It is widely used in precision transmission of robot wrist joints due to its small size and large transmission ratio. As the key component of nutation reducer, the tooth contact characteristics of double-circular-arc spiral bevel gear directly determine the service performance of the system, and is also an important basis for the parameter design and strength calculation of the reducer.
In order to obtain the contact point distribution, contact stress, coincidence degree and load distribution coefficient of spiral bevel gears, scholars have carried out relevant research. Dong Shujing takes spiral bevel gears as the research object, and uses the tooth contact analysis (TCA) method to obtain the tooth contact trajectory. Zhang Bo et al. obtained the tooth surface contact points of spiral bevel gears using Ease-off difference surface calculation method.
In order to clarify the influence of installation error on the contact characteristics of spiral bevel gears, Wang Zhonghou et al. established the contact equation with installation error based on the meshing principle, and obtained the contact area of tooth surface under different installation errors. In order to clarify the meshing characteristics of spiral bevel gears under loading conditions, QUW et al. obtained the load and contact pressure distribution with time-varying meshing characteristics using numerical load tooth contact analysis (NLTCA). Compared with the theoretical numerical calculation method, the finite element method is more suitable for dealing with nonlinear contact problems because it can be close to the actual working conditions. Tang Jinyuan and others used the finite element method to carry out the load contact analysis of spiral bevel gears, and obtained the coincidence degree of a pair of spiral bevel gears. In order to deeply explore the loading and meshing characteristics of spiral bevel gears, Feng Gang and other researchers respectively explored the change law of the maximum contact stress on the tooth surface of spiral bevel gears with cracks and without cracks. Hou Xiangying et al. analyzed the tooth contact path, tooth contact pressure and load distribution coefficient of the gear under load conditions.
It should be pointed out that although there are many studies on the contact characteristics of spiral bevel gears, there are few studies on the contact characteristics of double circular arc spiral bevel gears nutation transmission, and only some research groups have done some research. Cai Yongwu et al. analyzed the contact stress of double circular arc spiral bevel gear through finite element method, and verified the feasibility of nutation transmission scheme through experiments. On this basis, Lin Zheng and others deduced the tooth surface equation and meshing equation based on the conjugate principle, and obtained the tooth surface contact trace, and analyzed the gear contact state at a specific time using the finite element method. It should be pointed out that although the previous research analyzed the contact state of the tooth surface through the finite element method, it did not give the change rule of the contact point of the tooth surface within a meshing cycle, nor did it give the coincidence degree and load distribution coefficient used to characterize the gear transmission performance, nor did it determine the impact of load and installation error on the transmission performance.
In view of this, the contact characteristics of double-arc spiral bevel gear nutation transmission will be analyzed based on the finite element method with the double-arc spiral bevel gear nutation reducer developed by the research group in the early stage as the research object. By analyzing the contact state of the tooth surface in a meshing cycle, the meshing law of the tooth surface of this type of transmission is revealed, and the influence law of load and installation error on the coincidence and load distribution coefficient is analyzed.