Sliding bearing lubrication and friction

About friction pair of basic research is mainly focused on the energy conversion mechanism of friction pair of sliding friction in the process of thermal stress and friction pair, the surface contact stress and cooperation in such aspects as part of the oil film lubrication bearing capacity study. Through research, domestic and foreign scholars on the coupling stress of high energy density of friction system had certain control mechanism and the analysis model, preliminary solved the thermal stability of friction drive system on the basis of a play or work problems, and through the test to obtain the friction contact region laws of temperature field and friction damage, but still can't explain the state of stress and strain and damage model, the relation between friction characteristics, system is unable to accurately reveal the friction pair under mechanical strength, thermal strength of cooperation with the friction mechanism. ( 2) Sliding bearing lubrication theory research need good lubrication in the sliding bearing, this is the important guarantee of bearing life and reliability. With the constant improvement of the load and rotating speed, puts forward a new lubrication characteristics of friction pair. Under overload, oil film thickness decreases, and further make the table surface roughness will become more significant: the influence of the rotational speed of further ascension, inertia force is proportional to the speed of the fluid dynamic pressure, will be more than fluid static pressure, dynamic characteristics of friction pair of dominant. For high-end rolling and sliding bearings, therefore, to study the mechanical properties and the oil film is the inevitable developing trend of modern bearing lubrication theory and technology, to provide the design of such bearing with independent intellectual property rights of calculation method and theoretical basis, is also the need of engineering practice, to improve the manufacturing level of equipment manufacturing industry in our country, improve the quality of products, participate in international competition has important theoretical significance and practical application value in terms of sliding bearing lubrication theory, has established a hydrodynamic pressure lubrication, hydrostatic lubrication, elastic fluid dynamic pressure embellish smooth, thin film lubrication, boundary lubrication and mixed lubrication theory, this provides a theoretical support for the development of bearing, at present, the pure oil bearing lubrication research mainly consider the work environment and Hertz contact mechanics model, the study of lubricating oil film stiffness and damping characteristics, temperature rise effect and bearing capacity, and USES the small disturbance linear bearing - analysis method research Nonlinear dynamic characteristics of rotor system both domestic and abroad, most bearing lubrication research mainly based on the classical lubrication theory, research on multiphase flow lubrication lubrication problem under the condition of less. In recent years, the bearing lubrication theory research is turning to high temperature, high speed, bad environment, such as pole terminal condition, and the flow pattern of multibody, heterogeneous, and so on under the complicated working condition of lubrication design calculation, etc. For heavy nc equipment of the sliding bearing, the current domestic research still has many problems, the oil film pressure field and oil flow field and temperature field of oil film theory of comprehensive system research rarely, although some specific tribological behavior and failure mechanism research, but not system, cannot be applied to the development of the product. Practical application is still frequent early wear resulted from the poor lubrication, investigate its reason, in addition to failing to right use of fluid lubrication theory is relatively mature, mainly lies in the classical lubrication theory itself has limitations. Nonlinear oil film force of the unstability of the rotor system is an important physical factors, it belongs to the typical type of conservative force and the external factors that affect it extremely complex, the mechanics model of oil film force also has obvious flaw. The most major difficulty is the existing unsteady nonlinear oil film force model is mostly numerical model, the lack of analytical expression. Nonlinear meansthe have larger displacement disturbance and the disturbance velocity, need to seek unsteady oil film force and disturbance non line basic expressions of displacement and speed of disturbance, and reveal the regularity of beauty in the study of nonlinear oil film force model has caused widespread concern, many experts in the field of mathematics and mechanics have proposed many expressions. Surface in domestic, the nonlinear oil film force of research carried out earlier, had the fund major projects, for the calculation of database and the fitting expression. However, in recent years, the job is a little silence. The calculation of oil film force is very important for the analysis of the stability of the rotor, the dragon is a problem of vertical rotor bearing, the analysis of the phase locked work remains to be further.