The effect of outer ring elastodynamics on vibration and power loss of radial ball bearings

Abstract

Ball bearings are an integral part of many machines and mechanisms and often determine their performance limits. Vibration, friction and power loss are some of the key measures of bearing performance. Therefore, there have been many predictive analyses of bearing performance with emphasis on various aspects. The current study presents a mathematical model, incorporating bearing dynamics, mechanics of rolling element-to-races contacts as well as the elastodynamics of the bearing outer ring as a focus of the study. It is shown that the bearing power loss in cage cycles increases by as much as 4% when the flexibility of the outer ring is taken into account as a thick elastic ring, based on Timoshenko beam theory as opposed to the usual assumption of a rigid ring in other studies. Geometric optimisation has shown that the lifetime power consumption can be reduced by 1.25%, which is a significant source of energy saving when considering the abundance of machines using rolling element bearings. The elastodynamics of bearing rings significantly affects the radial bearing clearance through increased roller loads and generated contact pressures. The flexible ring dynamics is shown to generate surface waviness through global elastic wave propagation, not hitherto taken into account in contact dynamics of rollers-to-raceways which are generally considered to be subjected to only localised Hertzian deflection. The elastodynamic behaviour reduces the elastohydrodynamic film thickness, affecting contact friction, wear, fatigue, vibration, noise and inefficiency.

Dynamics of a planetary needle roller bearing considering the waviness

“…The bearing rings and housing are supposed to be rigid ones in this analysis. The ring and housing deflections 33,34 are not considered in this PNRB dynamic model. 2.…”

“… The bearing rings and housing are supposed to be rigid ones in this analysis. The ring and housing deflections 33,34 are not considered in this PNRB dynamic model. The temperature change can affect the bearing vibrations. 23 However, this PNRB model is established under the isothermal conditions and doesn’t consider the temperature changes. The needle roller skewness is not considered in this dynamic model.…”

Effect of thermal elastohydrodynamic lubrication on vibration characteristics of ball bearing with local defect

“…Sivayogan et al 20 conducted an isothermal elastohydrodynamic analysis model of the elliptical point contact to study the transient influence of oil film extrusion and separation. Turnbull et al 21 integrated the elastodynamics with outer raceway for ball bearing into a dynamic model to analyse the power loss of bearing and lubricating performance of contact zone. Gao et al 22 considered the influence of lubricating oil film and presented a dynamic model with multiple surface defects for ball bearing to study the included angle and number of defects on vibration response.…”

Subsurface stresses analysis of flexible ball bearing with bendable races in a harmonic reducer by superimposition method

“…A lot of research has been conducted on bearings with flexible races, such as planet gear bearings of planetary gear power transmission system, yaw bearings for wind turbines and tower cranes, cylindrical roller bearings for the aero-engine rotor, and FBs for harmonic reducers. [5][6][7][8][9][10][11] The structural deflection of the races must be considered to solve the contact load since it can alter the load distribution of the bearings, and subsurface contact stresses distribution on the races is very different from that considering only contact deformation. However, the above studies are mainly to establish a static model or dynamic model to obtain load distribution and parameter influencing rules of the bearings, and subsurface stresses are rarely involved.…”