Study On Optimum Design Of Super-high Speed Hybrid Journal Bearing Parameters

The super-high speed grinding is a kind of Advanced Abrasive machining. It can improve production efficiency and surface quality of machining. It is the current trend of grinding technology. Super high speed spindle and bearing technology is one of key technologies of super-high speed grinding. A basic shaft of super-high speed machine tool must reach high gyration accuracy, and insert bearing is critical faction. Now, hybrid journal bearing with high rigidity and high gyration accuracy are used in super-high speed machine tool. But, hybrid journal bearing is different from hydrodynamic bearing and hydrostatic bearing, so it has not establish a more complete set of design methods in structural design and structural size, moreover, there is no more consistent design standards and technical specifications, especially in the oil cavity of the selected parameters are often dependent on a number of empirical data, thus, the characteristics of hybrid journal bearing is not to be fully reflected in the project and immature design techniques led to limitations in the premature application. So, if use various conditions under the given conditions and factors (e.g. given speed), consider the influence on bearing stiffness, loading capacity, working conditions, reference characteristics and design method of hydrodynamic bearing and hydrostatic bearing and establish necessary mathematical model for main structural size, thus, by further parameter optimization of hybrid journal bearing can make it reach relatively well-designed result, meanwhile, the features of hybrid journal bearing can also be fully played. The aim of is to get more scientific and rational geometry structural parameters and design methods, and, broaden hybrid journal bearing applications in engineering.In this paper, the basic mathematical model of hybrid journal bearing parametric design has been established, and oil film thickness equation, energy equation, viscosity-temperature relationship equation, temperature rise equation are also derived. The pressure equation is established on the basic of continuity equation and momentum equation, meanwhile, this paper establish Reynolds equation and analysis its differential form and flow continuity equation. The main mission is to establish objective function equation and boundary conditions of optimal design, deal with them, and establish optimal design analysis method of hybrid journal bearing.On the basis of theoretical analysis, objective function and boundary conditions are simplified, complex method is used to solve objective function and get parameter optimization results of bearing, lastly, drawing the optimal design of three-dimensional map. This paper also analysis the relationship between temperature rising and optimization results, and get some significant conclusions; proposed improve the effective measures of hybrid journal bearing stability, established a full set methods of hybrid journal bearing design. At last, on the basic of super-high speed grinding platform, this paper makes main experimental study on temperature in high-speed operation.