Study On Thermal Characteristics Of Meshing Pair Of Two Tooth Difference Swing Rod Movable Teeth Transmission

The two teeth difference oscillating rod movable gear drive belongs to a new type of planetary gear drive with few teeth difference.It has the advantages of good dynamic balance performance,stable transmission,integrated structure,high meshing efficiency,strong bearing capacity,used in the fields of robots,medical instruments,agricultural machinery equipment etc.In the high speed and heavy load conditions,the heat flux density is relatively large,due to the high power density and swing speed reduction output mechanism integrated the rod movable teeth drive.The temperature distribution of meshing surface will be more complex.The non-uniform thermoplastic deformation caused by this will lead to the time-varying stiffness of the meshing stiffness.Therefore,it is of great significance to study the thermal behavior of the movable teeth drive system.In this paper,According to the theory of Hertz,tribology and theoretical mechanics,the calculation method of maximum contact stress,meshing relative sliding velocity and time-varying friction coefficient in the formula of temperature rise are given.The MATLAB software is used to draw the curve of transient temperature rise.The influence of design parameters on the instantaneous contact temperature rise of meshing pairs is studied.According to the theory of heat transfer,the heat balance equation of the temperature field of the meshing pair and the boundary condition formula of each calculation area are derived.Using MATLAB numerical calculation,meshing heat flux and convective heat transfer coefficient curve are obtained.Based on the ANSYS numerical simulation analysis,the swing rod movable teeth drive meshing pair of body temperature distribution are get.The influence of tooth profile factors and lubricant temperature on the body temperature was studied.Based on the thermal stress theory,the meshing model and thermal elastic analysis model of the meshing pair are established.The calculation of the time-varying rectangular contact domain is carried out and the thermal deformation of the meshing pair is calculated by the Green function method.In order to obtain the law of thermal and thermal stress distribution of the single meshing model of meshing pair,the method of sequential coupling analysis is used as the initial condition and the ANSYS Workbench is used to analyze the thermal structure.The influence of the profile parameters on the thermal stress and thermal deformation is also analyzed.The results show that the instantaneous contact temperature rise decreases with the increase of the swing rod length and the radius of the movable teeth,and increases with the swing coefficient and the radius of the movable rack.The appropriate reduction of swing rod movable teeth increase length,radius and amplitude coefficient,and by improving the cooling condition of transmission mechanism to reduce the temperature of lubricating oil,can reduce the temperature of the center wheel and meshing pair of thermal deformation and thermal stress.The steady temperature of the center wheel is the main cause of thermal stress and thermal deformation,but the maximum thermal stress and the maximum thermal deformation zone do not coincide with the highest temperature point due to the influence of the central gear shape.After considering the thermal deformation,the meshing stiffness of the movable teeth meshing pair is remarkably reduced.