Effects of Some Hydraulic Fluid Lubricants on the Fatigue Lives of Rolling Bearings

1968 ◽  
Vol 183 (16) ◽  
pp. 21-27 ◽  
Author(s):  
R. A. Hobbs ◽  
G. W. Mullett
Keyword(s):  
Ball Bearing ◽  
Fatigue Testing ◽  
Mineral Oil ◽  
Equipment Design ◽  
Hydraulic Fluid ◽  
Oil Lubrication ◽  
Rolling Bearings ◽  
Test Conditions ◽  
Hydraulic Equipment

Hydraulic equipment operating in potentially explosive or inflammable atmospheres (e.g. pumps in mines) has to use special fluids which are fire-resistant. Frequently the equipment design is such that the same fluid is used to lubricate rolling bearings. It is already known that some fluids, particularly those containing water, cause a serious reduction in the fatigue lives of the bearings. This paper describes a ball bearing rig and the test conditions under which several fire-resistant fluids were evaluated. It compares the fatigue lives obtained with the lives obtained when using mineral oil lubrication. Factors by which bearing capacities should be reduced when using these fluids are suggested. The fatigue testing of batches of bearings is time-consuming and the fluids are continually undergoing development. There is thus some difficulty in keeping up-to-date. However, the capacity factors given are indicative of the magnitudes of the effects that fire-resistant fluids can have on bearing lives.

Oil Pumping in High Speed and High Loaded Ball Bearings

2004 ◽  
Author(s):  
Michael Flouros
Keyword(s):  
High Speed ◽  
Ball Bearing ◽  
Research Programme ◽  
Aircraft Engine ◽  
Ball Bearings ◽  
European Research ◽  
Rolling Bearings ◽  
Engine Design ◽  
Oil Flow ◽  
Total Oil

Trends in aircraft engine design cause increased mechanical stress requirements for rolling bearings. Consequently high amounts of heat are rejected which results in high oil scavenge temperatures. The direction of oil flow in the bearing can considerably affect the heat transported by the oil. An RB199 turbofan bearing and its associated chamber were modified to carry out the survey. The test bearing was a 124mm PCD ball bearing. The bearing has a split inner-ring employing under-race lubrication by two individual jets. The total oil flow could be devided to any ratio through the jets. This had an impact on the oil scavenge temperatures and the scavenge flows on both sides of the bearing. Significant reduction in the ‘heat to oil’ was achieved when oil was fed at certain proportions (ratio). This work is part of the European Research programme Brite Euram ATOS (Advanced Transmission and Oil Systems).

Hysteretic Resonances and Intermittency Chaos in Ball Bearings

2018 ◽  
Author(s):  
Zhiyong Zhang ◽  
Xiaoting Rui ◽  
Yushu Chen ◽  
Wenkai Dong ◽  
Lei Li
Keyword(s):  
Ball Bearing ◽  
Harmonic Balance Method ◽  
Rolling Bearing ◽  
Hertzian Contact ◽  
Ball Bearings ◽  
Rolling Bearings ◽  
Rotor Systems ◽  
Revolute Joints ◽  
Rolling Elements ◽  
Varying Compliance

Ball bearings are essential parts of mechanical systems to support the rotors or constitute the revolute joints. The time-varying compliance (VC), bearing clearance and the Hertzian contact between the rolling elements and raceways are three fundamental nonlinear factors in a ball bearing, hence the ball bearing can be considered as a nonlinear system. The hysteresis and jumps induced by the nonlinearities of rolling bearings are typical phenomena of nonlinear vibrations in the rolling bearing-rotor systems. And the corresponding hysteretic impacts have direct effects on the cleavage derivative and fatigue life of the system components. Therefore, the behaviors of hysteresis and jumps are given full attentions and continued studies in the theoretical and engineering fields. Besides, many researchers have done a lot of calculations to depict the various characteristics of bifurcations and chaos in the rolling bearings and their rotor systems, but few researches have been addressed on the inherent mechanism of the typical intermittency vibrations in rolling bearings. With the aid of the HB-AFT (the harmonic balance method and the alternating frequency/time domain technique) method and Floquet theory, this paper will investigate deeply the resonant hysteresis and intermittency chaos in ball bearings.

Effects of pre-corrosion, water and detergent contamination on rolling contact fatigue

2020 ◽  
Vol 21 (3) ◽  
pp. 310
Author(s):  
Wen Wang ◽  
Xiaopeng Hao ◽  
Xiaomeng Chen ◽  
Bo Han ◽  
Xiaobo Zhou
Keyword(s):  
Water Contamination ◽  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
Microscopic Analysis ◽  
Energy Dispersive Spectrum ◽  
Mineral Oil ◽  
Rolling Contact ◽  
Test Conditions ◽  
Negative Effect ◽  
Scanning Electron

The effects of pre-corrosion, water and detergent contamination in Shell Turbo 32 (T32) mineral oil on rolling contact fatigue (RCF) life of rollers were experimentally investigated using a home-made ball-on-roller tester. The tested roller samples were analyzed by a scanning electron microscope (SEM) and an energy dispersive spectrum (EDS). The results show that the fatigue life of the rollers is reduced by all test conditions where the negative effect is enhanced with increasing the pre-corrosion time, from surfactant detergent to water contamination and to alkaline detergent. Microscopic analysis indicates that spalls on the rolling contact track are mainly surface initiated.

Hydraulic Fluid Viscosity Selection for Improved Fuel Economy

2008 ◽  
Author(s):  
Paul Michael ◽  
Steven N. Herzog
Keyword(s):  
Power Systems ◽  
Fuel Economy ◽  
Major Influence ◽  
Fluid Viscosity ◽  
Hydraulic Fluid ◽  
Hydraulic Equipment ◽  
Fluid Properties ◽  
Selection For ◽  
Fluid Power Systems ◽  
The Relationship

Fluid properties have a major influence upon the energy efficiency of hydraulic equipment. The relationship between hydraulic fluid viscosity, shear stability and system fuel economy has been studied. New viscosity selection guidelines for hydraulic pumps and motors are proposed. These guidelines provide a means for improving the efficiency of fluid power systems.

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