Effect of surface roughness, viscosity-pressure relationship and elastic deformation on lubrication performance of misaligned journal bearings

Abstract

Purpose – Current lubrication analyses of misaligned journal bearings were generally performed under some given preconditions. To make the lubrication analysis closer to the actual situation and usable to the journal bearing design, the purpose of this paper was to calculate the lubrication characteristics of misaligned journal bearings considering the viscosity-pressure effect of the oil, the surface roughness and the elastic deformation of the journal bearing at the same time. Design/methodology/approach – The lubrication of bearings was analyzed using the average Reynolds equation. The deformation of the bearing surface under oil film pressure was calculated by a compliance matrix method. The compliance matrix was established by finite element analysis of the bearing housing. The viscosity-pressure and viscosity–temperature equations were used in the analysis. Findings – The oil viscosity-pressure relationship has a significant effect on the lubrication of misaligned journal bearings. The surface roughness will affect the lubrication of misaligned journal bearings when the eccentricity ratio and angle of journal misalignment are all large. The directional parameter of the surface has an obvious effect on the lubrication of misaligned journal bearings. The deformation of the bearing surface has a remarkable effect on the lubrication of misaligned journal bearings. Originality/value – The lubrication characteristics of misaligned journal bearings were calculated considering the viscosity-pressure effect of the oil, the surface roughness and the elastic deformation of the journal bearing at the same time. The results of this paper are helpful to the design of the bearing.

Simulation of journal bearing friction in severe mixed lubrication – Validation and effect of surface smoothing due to running-in

“…Both papers conclude that a worn bearing geometry decreases the bearing temperatures. Sun et al [24] calculate the effect of surface roughness change on misaligned journal bearings and highlights the importance of elastically deformation of the contacting bodies. However, no contact model is implemented to discuss friction due to asperity interaction.…”

On the Characteristics of Misaligned Journal Bearings

“…The temperature of the oil film was investigated under different misalignment angles and surface roughness. Sun et al [73] in 2014 analyzed the lubrication characteristics of misaligned journal bearings considering the viscosity-pressure effect of the oil, the surface roughness and the elastic deformation at the same time. They found that the oil viscosity-pressure relationship and the deformation of the bearing have a significant effect on the lubrication of misaligned journal bearings.…”

Friction coefficient and performance evaluation of plain journal bearing using SAE 5W-30 engine oil

“…Reduced friction ensures better performance of journal bearing. 29,30 Generally, fluid bearings can be lubricated hydro-dynamically or hydrostatically. 31 It is important to take greater care to design and operation for hydrodynamic bearing than hydrostatic bearing.…”

“…Due to the piezo-viscous effect of the lubricant, the friction coefficient was minimized around 0.004–0.009 at different load capacities compared to previous studies. 16,20,28,30,37,43–45 The change of rotational speed and viscosity of the lubricant are highly concerning issues to investigate the bearing performance which includes the stress, pressure on the bearing, pressure, and so on. 46,47 Minimal variations in lubricant temperature were observed during test duration which prescribes the suitability of the lubricant as viscosity reduces due to the increase of the temperature.…”