Numerical Analysis Of Transient Thermal Mixed Lubrication In Point Contact

At present,more and more mechanical equipment is operated under heavy load.The pressure tends to concentrate on a very small contact surface during operation of many heavy-duty equipments,which results in very large working pressure and elastic deformation.Due to the roughness of the surface of the component,there is a direct solid-solid contact in some places at the interface(contact zone),and some places are separated by lubrication oil(fluid zone),which is often referred to as mixed lubrication.At present,the numerical research mainly focuses on the thermostatic mixed lubrication and there are few studies on thermal mixed lubrication,but the heavy load will inevitably lead to high temperature.Therefore,considering the mixed lubrication in the temperature field is more in line with the actual situation.In this paper,the thermal mixed lubrication model is established,the numerical simulation method is used to study the thermal mixed lubrication phenomenon of ball bearings under different working conditions,and the influence of temperature field on its lubrication performance is analyzed.Firstly,the calculation method of solid surface temperature field is studied.The calculation accuracy and calculation efficiency of matrix approximation,Green function and linear interpolation are compared.It is found that Green function method is suitable for mixed lubrication thermal analysis.Secondly,a transient thermal mixed lubrication model is established based on the surface temperature rise equation,the oil film temperature equation and the unified Reynolds equation system.The main characteristics of thermal mixed lubrication are obtained by numerical analysis.The changes of oil film pressure,thickness and temperature field during thermal mixed lubrication transient process are studied,and the influence of temperature field on lubrication performance is analyzed.Finally,the angular contact ball bearing thermal analysis model is established by combining a thermal mixed lubrication model with an angular contact ball bearing motion model.The oil film pressure,thickness and temperature field distribution under different working conditions are studied,and the effects of parameters such as the rolling speed of bearing rolling elements,bearing contact angle and matching degree on the lubrication performance are analyzed.