Study On Principle Of Geometric Elements Constructed Tooth Pairs With Curve-surface Mesh And Its Application

The gear is the key element to realize the transformation of motion and power.It has the characteristic of constant power transmission and determines the performance of the equipment to a large extent.Therefore,gear has a very important strategic position in the national economic construction and national defense construction.The development of China's space industry has been in the forefront of the world.The rapid development of aerospace industry raises higher performance requirements for gear transmission,such as long life,high precision,high bearing capacity and so on.The research of high performance gear has become a technical issue in the industrial field.Basic theory is an important part of gear research,and it is also a key element of gear innovation and development.Point,curve,and surface are the most basic geometric elements.In the existing meshing theories,surface-surface and curve-curve meshing have been fully explained and discussed.Taking curveand surface as the starting point,a newmeshing theory named curve-surface mesh is established and a high performance gear transmission--geometric elements constructed tooth pairs with curve-surface meshis putforward.The research is focused on the principle and meshing characteristics.The main research work of this paper can be summarized as follows:(1)Based on the theory of curve-curve and surface-surface mesh,the concept of curve-surface contact and curve-surface mesh is put forward.The variety of curve-surface mesh is analysed and three main factors are given.The basic principle is described,spatial coordinates are esetablished and relative velocity is solved.By given the surface and the contact path,the contact direction is derived and the mesh equation is obtained.The space curve that is engaged with the surface and the mesh line is deduced.The tooth surface is formed by the continuous change of the normal section curve along the space curve and the three-dimentional model is established.By using the differential geometry,the geometrical characteristics is analysed,the existence and uniqueness of space curve is varified and the calculation method of meshing line curvature and torsion is putforward.(2)According to the basic principle of curve-surface mesh,geometric elements constructed tooth pairs with curve-surface mesh is put forward.The contact path,mesh equation and the equation of tooth surface is derived.According to the gear parameters,precise model of the gear pair is established by using MATLAB and UG.A simple method for the construction of the gear pair is put forward based on the characteristic of identity.(3)The general condition of tooth surface does not undercut and interference analysis isdiscussed.The calculation theory and method of tooth surface sliding ratioestablished.The ablility of error ajustment to center distance is discussed.According to the meshing characteristcs of the gear pair,the calculation method of contact ratio is put forward.Tooth contact analysis is carried out.The mathematical models of the gear pair under different conditions of center distance errorsare established and the contact paths and transmission errors are obtained.(4)The international space station is introduced and the shortcomings are analysed.Baed on geometric elements constructed tooth pairs with curve-surface mesh,a new approach of solar alpha rotary joint is put forward.The ablility of error ajustment to center distance,contact stress are calculated and simulated.Finite element contact model is established and solved by using ANSYS.The result is obtained and it demonstrates the loading capability and the pattern of point contact.In addition,the result validates that the gear pair can mesh correctly under center distance errors,which is consistent with the theoretical analysis.(5)The1:2 shrinkage test rig is established and the work of installation and debugging are finished.The running experiment and verification experiment are completed.The 1:1 test rig is established and the running experiment,performance experiment,life experiment and contrast experiment is accomplished.According to the verification experiment and entity model experiment,the new approach is fully verified and lays an experimental foundation for its application.