Static characteristics analysis of spherical hybrid sliding bearings

Abstract

Purpose The spherical hybrid sliding bearings (SHSBs) can be used in ultra-precision and heavy-duty machine tools. However, there is little related research for these bearings. The purpose of this study is to investigate the static characteristics and effect factors affecting SHSBs by fluid lubrication. Design/methodology/approach Based on the theories of fluid lubrication, the Reynolds equation of general Newtonian fluid is derived to obtain the steady-state lubrication equation. The system is solved by the finite difference method and the relaxation iterative method on the staggered grid to obtain the thickness and the pressure distribution of the oil film. The radial and axial load capacities of SHSBs are determined by the pressure field integration over the spherical surface. Findings The results show that the parameters such as oil supply pressure, bearing clearance, eccentricity ratio, rotating speed and orifices’ number affecting the static characteristics of bearings are significant and the cross-coupling effect exists. Originality/value The lubrication model of SHSB is established to analyze the pressure distribution with a variety of oil film thickness. The laws of oil supply pressure, bearing clearance, eccentricity ratio, rotating speed and orifices’ number on the load capacities are researched.

Study on dynamic characteristics of acceleration process of spherical hybrid sliding bearings rotor system

“…On the basis of equation (4) of continuity, combining with Newton’s law of viscosity and hypothesis of Reynolds equation (Wang et al , 2019), the nonlinear dimensionless Reynolds equation (6) of SHSBs was derived in the spherical coordinate system: …”

“…The spherical hybrid sliding bearings (SHSBs) provide high rotating accuracy, high dynamic stiffness, high vibration damping and long life cycle (Wang et al , 2019), which are suitable for use in high-precision lathes and grinders. The 3D model of SHSBs is shown in Figure 1.…”

“…Li et al (2019) investigated the dynamic performance of the aerodynamic journal bearings–supported rotor under constant speed operating conditions. Wang et al (2019) investigated the nonlinear dynamics of a spherical gas-lubricated bearing rotor by using the hybrid numerical method, which combines the differential transform method with the finite difference method. Meruane and Pascual (2008) established the mathematical model of the plain bearing to study the variation of axial trajectory and identified the nonlinear coefficients of the bearing.…”

Simulation evaluation of dynamic characteristic identification accuracy of sliding bearing considering test error

“…1,2 It is an important supporting component in rotating machinery. A relatively welldeveloped theoretical system has been established for hundreds of years, [3][4][5] but in practical applications, the service performances of the bearing are usually greatly different from the theoretical analysis results, especially the dynamic characteristics. 6,7 In linear theory, the dynamic characteristics of bearings are characterized by stiffness and damping coefficients, mainly using conventional 8-coefficient model, 8,9 frequency-varying 8-coefficient model, 10,11 complete dynamics model, 12,13 etc.…”