Parametric modeling and simplified model of helical gear

To obtain accurate gear contact stress, the premise is to create an accurate three-dimensional solid model, and the creation of accurate tooth profile surface is the key. With the emergence of various large-scale CAD software and the rapid development and application of CAD technology, the establishment of gear model has developed slowly. Because people have higher and higher requirements for gears, the design speed of CAD system is faster, and the quality and accuracy of the generated model are higher. Many scholars carry out secondary development of gears based on different CAD software. The accurate parametric analysis of cylindrical gear is established by using ANSYS / Pro, which provides the accurate parametric analysis of cylindrical gear in the subsequent development of E / Pro. Wang Xiaoyong proposed the method of modeling and Simulation Research of gear reducer based on UG. Zhou Xueliang and others established the parametric gear model in UG software, and then used UG / open for secondary development to complete the parametric modeling of involute cylindrical helical gear.

Xiao Shilin et al. Used the modeling function of CATIA software and the expressions of involute and helix established in the software to complete the parametric modeling of involute spur gear. Wang Bo realized the parametric modeling method of involute helical gear by using parametric formula in CATIA environment, and discussed the application of parameterization in design. Li Changyi and others have studied the generation principle and technical implementation method of involute cylindrical gear parameterization by using ANSYS software, and have good practical application effect. Liu Zhizhu and others completed the parametric modeling of standard involute gear by using ANSYS parametric design language in ANSYS software and combined with the integrated development environment of Visual C + +. Under the environment of solid works, Lulian et al. Realized the parametric modeling of involute spur gear and helical gear by using the spline curve fitting method and VB language, which provided an accurate model for the subsequent modal analysis. Due to the large amount of three-dimensional finite element simulation calculation of helical gear and limited computer resources, many scholars mostly use local tooth model instead of full tooth model in gear finite element analysis to improve the analysis efficiency. Yang fenai and Liu Pengfei studied the static contact strength of helical gear in ANSYS by using three tooth model without rim and three tooth model with rim respectively. Li Jie verified that the three-dimensional multi tooth finite element contact model is the closest to the actual operation of the gear through the contact finite element analysis of helical gear with local three tooth model without rim, Shang Zhenguo used the five tooth model without flange to investigate the load distribution between the teeth and the load distribution on the contact line before and after the modification of the helical gear profile. Fan Zenghui used the five tooth model without flange to conduct the contact nonlinear finite element analysis in the finite element analysis software ANSYS, and Zhao Yumin used the 1 / 4 model of the helical gear body to theoretically calculate and study the static characteristics of the transmission gear, Tang Yi adopted the three tooth model without rim, and through the dynamic contact analysis of helical gear, obtained the law of tooth load and the change law of contact line in the process of gear meshing. Because the coincidence degree of helical gear is relatively large, and the existence of rim has a certain impact on the uniform stress of gear in gear loading, in the above article, most scholars use three tooth belt rim and no rim model, five tooth belt rim and no rim model to study its performance in the strength analysis of helical gear. Although M. Celik has used the finite element method to compare and study the relationship between tooth stress and strain of local three tooth spur gear model and full tooth spur gear model, it is obviously not suitable to use the two-dimensional finite element method to analyze the contact of helical gear due to the structural shape and bearing characteristics of helical gear.

To sum up, many scholars have carried out parametric modeling of gears to varying degrees and adopted different types of local tooth models for subsequent finite element analysis to improve work efficiency.