Study On Static Dynamic And Tribological Property Of Rolling Bearings

Rolling bearings, one of the important parts in machines, are used to support rotating parts and wear is reduced for the rolling friction as force is applied on it. Rolling bearings are widely used in mechanical engineering because of their good starting performance, good operational reliability, easy maintenance and high load capacity at the moderate speed. High speed, high power and high precision are becoming developing directions of modern machines, so that it is necessary to accurately speculate working life of the bearing. A effective way is to study relevant problems such as the statics, dynamics and tribology of the bearing.Firstly, the current research review on statics, dynamics and tribology about rolling bearings is analyzed in this paper. A deep groove ball bearing is selected as an example, the problem of supporting stiffness of rolling bearings is researched. It is a multiple static indeterminate problem for there are many rollers in the bearing. Therefore, force method is selected to solve the static indeterminate problem so that analytic expression of supporting stiffness can be obtained. Multiple factors can affect on supporting stiffness such as position change, radial clearance, different axial load and different centrifugal force on bearing stiffness. In order to verify the relationship between the force on rolling bearings and their deformation, an indirect testing rule of measuring radical displacement of the bearing is proposed, and corresponding testing system is designed.Secondly, the dynamic problem of rolling bearings is analyzed. The rolling bearing is one of a multi-body dynamic system, because there are many moving components such as rolling element, retainer, inner or outer ring and other movement members in the bearing. The interaction among the moving parts of the bearing is complex so that shock and local deformation happen inevitably. The dynamic problem of the bearing is complicated and very difficult to solve. Dynamic simulation software ADAMS is employed to establish quasi-rigid-body dynamical model for a deep groove ball bearing, in which local contact deformation between inner and outer rings of rolling elements is taken in consideration. The Hertz’ Theory is employed to calculate the force and deformation between the inter-contact parts of the bearing and Fortran language is selected to edit the programs to calculate the relationship between applied force and deformation of the bearing. The program is made up to a dynamic-link library(DLL) in order to be called in ADAMS through its outer interface. The dynamic radial force applied on the rollers and the relative sliding velocity between the roller and the inner or outer rings are obtained through dynamic simulation in ADAMS. The result is useful for the lubrication analysis of the bearing.Thirdly, a theoretical framework is proposed to solve the elasto-hydrodynamic lubrication(EHL) problem of rolling bearings based on dynamic analysis. It is feasible to study the EHL problem.Finally, the main work and the main innovation are summarized in the paper, and some problems about future research about rolling bearing are proposed.