In modern mechanical transmission, cylindrical spur gear transmission is the most important type of transmission. It consists of the main and driven wheels, which transmit motion and torque through the meshing between cylindrical spur gears. A pair of meshing modified gears, when machining a small gear, the tool is kept a distance away from the gear blank, and when machining a large gear, the tool is kept an equal distance away from the gear blank. This way, the pitch circle and indexing circle of the meshing cylindrical spur gear still coincide, and the full tooth height remains unchanged. However, the position of the tooth root circle and tooth top circle relative to the indexing circle has changed, which is called a highly modified cylindrical spur gear. To meet the performance requirements of cylindrical spur gear transmission, especially to avoid undercutting, reduce structure, adjust center distance, improve wear of cylindrical spur gears, and increase load-bearing capacity, modified cylindrical spur gears are often used to extend the service life of gears, and their applications are very extensive.
At present, Wu Xiaohua and Wang Shengman have studied the theory of contact and finite element analysis, built a finite element analysis model using UGNX, and conducted dynamic simulation analysis on cylindrical spur gears using this software, obtaining displacement cloud maps and stress cloud maps, which meet the performance requirements of cylindrical spur gear transmission. Lin Zhiqi and others studied the 3D modeling of cylindrical spur gears using Solidworks, and statics analysis of the model using AnsysWorkbench, and compared the influence of mesh division on the accuracy of the analysis results. Cui Hongbo proposed using MATLAB and Solidworks to jointly model, and conducted finite element analysis on the involute model, concluding that the joint modeling resulted in higher tooth profile accuracy. Fang Muwen studied the Pro/E 3D modeling of modified cylindrical spur gears and conducted finite element analysis using Ansys. It was concluded that with an increase in the modification coefficient within a certain range, the tooth contact stress and tooth root bending stress would decrease.
The above research results have positive reference significance for the scheme design and structural optimization of cylindrical spur gear transmission. Research is conducted on the geometric calculation of cylindrical spur gear transmission. Based on UG (CAD), three-dimensional parametric modeling of highly modified cylindrical spur gears is carried out, and the transient force analysis of the transmission gear is conducted using AnsysWorkbench software to obtain the maximum stress value and concentration point of the simulation of cylindrical spur gears. At the same time, the theoretical stress value of the transmission gear was calculated using the Hertz formula, and the theoretical stress value was compared with the simulated stress value. The calculation error was found to meet the requirements of the working conditions, providing scheme support for the structural design and optimization of highly modified cylindrical spur gears.