Effect of grease on bearing vibration performance caused by short-time high-temperature exposure

Abstract

A short-time high-temperature environment is a common working condition in the use of bearings; it can occur as rapid heating before interference assembly of a bearing, or in a quick shutdown due to failure and heating of other parts of equipment. However, the current research mainly focuses on the influence of long-term high temperatures on bearing lubrication. In this paper, the 6204DDU ball bearing with lithium soap/mineral oil (paraffin base type) grease and fatty acid soap/mineral oil (refined white oil) grease (white grease) is investigated. The recovery performance of the two greases after a short-time high temperature is studied. It is found that a large number of fractures occur in the soap fibre of the white grease after 20 min exposure in 140 °C temperature environments, while lithium grease remains in a good working condition. The vibration velocity with white grease decreases during a temperature falls from 110 °C to the heated balanced temperature, while the vibration velocities with lithium grease is without significant fluctuations. Before and after heating, the vibration velocities in middle frequency band of rolling bearings with lithium grease and white grease increase with the increase in preload, but it is the opposite in the high frequency band except for white grease after heating condition. Infiltration with a small amount of water or oil can greatly affect the performance of white grease. Water can emulsify the white oil and accelerates the oxidation of white grease. The structure of the L-AN32 oil contaminant is different from that of white oil, resulting in uneven dispersion of saponified crystals and obvious flocculent agglomeration is presented.

Investigations for vibration and friction torque behaviors of thrust ball bearing with self-driven textured guiding surface

“…The RMS of GGB decreased most in the middle and high frequency bands, 65.3% and 48%, respectively. According to previous study [36], the low-frequency, medium-frequency, and high-frequency vibration of the bearing is mainly determined by the geometrical morphology, the waviness and the surface roughness of the raceway, respectively. Serrato et al [37] reported that the changes in lubrication condition of a rolling bearing mainly affect its vibration in 600-10,000 Hz, and the reduction of oil film could cause the small impact among metallic surface irregularities (roughness/ waviness), which increase the bearing vibration, 12 Friction | https://mc03.manuscriptcentral.com/friction especially in medium and high frequency bands.…”

Assessing the fatigue wear effect on traction coefficient and dynamic performance of roller bearing

“…The vibration intensity increases with respect to the rise in preload because it sifts the lubrication regime from EHL to boundary lubrication, which results in a drastic increase in vibration levels. 18 According to Masjedi and Khonsari 11 the equation of minimum oil film thickness (h min ) has a direct impact on the lubricant film stiffness of roller bearings. The minimum oil film thickness (h min ) formed between the roller and the inner and outer raceways under isothermal and adequate oil supply conditions can be calculated by using the equation available in Appendix 1.…”

“…The vibration intensity increases with respect to the rise in preload because it sifts the lubrication regime from EHL to boundary lubrication, which results in a drastic increase in vibration levels. 18…”

“…This study presented an efficient procedure to combine film effects into a lateral vibration model of a deep groove ball bearing. Wu et al 18 analysed the effect of grease lubrication on the dynamic behaviour of a bearing that was subjected to high-temperature operating conditions for a short period. In this experimental investigation, authors have introduced a grease lubrication model and mathematical formula that provide the estimation details of lubricating oil film stiffness.…”

Research on the effect of structural and material parameters on vibrations based on quasi-static model of bearings

“…With the help of model simulation, more phenomena can be obtained as a Ref. [21][22][23]. Hertz [24] gave a reasonable explanation for local contact, which laid a theoretical foundation for the static analysis of rolling bearings.…”