A Study of the Lubrication and Dynamics of Geometrically Perfect, Lightly Loaded, Cylindrical Roller Bearings with Particular Reference to Shaft Loci

1976 ◽  
Vol 18 (6) ◽  
pp. 263-270
Author(s):  
P. H. Markho ◽  
D. Dowson
Keyword(s):  
Roller Bearing ◽  
Lubricant Film Thickness ◽  
Roller Bearings ◽  
Rolling Element ◽  
Cyclic Movement ◽  
Bearing Loads ◽  
Initial Clearance ◽  
Cylindrical Roller Bearing ◽  
Cylindrical Roller ◽  
Steady Load

The principal objective of this paper is to ascertain and quantify the cyclic movement of the centre of a shaft in a geometrically perfect, lubricated, cylindrical roller bearing exhibiting initial clearance and subjected to a light and steady load. The movement may be important in relation to the accuracy of location of shafts in roller bearings, and it is shown that a detailed consideration of the rolling element assembly predicts some interesting effects. The study also covers more conventional features of bearing performance such as lubricant film thickness and coefficient of friction, and shows the effect of squeeze to be negligible under steady bearing loads.

Investigation on the drag effect of a rolling element confined in the cavity of a cylindrical roller bearing

2021 ◽  
pp. 135065012110260
Author(s):  
Wenjun Gao ◽  
Shuo Zhang ◽  
Xiaohang Li ◽  
Zhenxia Liu
Keyword(s):  
Open Space ◽  
Roller Bearing ◽  
Flow Characteristics ◽  
Experimental Tests ◽  
Windward Side ◽  
Leeward Side ◽  
Drag Effect ◽  
Rolling Element ◽  
Cylindrical Roller Bearing ◽  
Cylindrical Roller

In cylindrical roller bearings, the drag effect may be induced by the rolling element translating in a fluid environment of the bearing cavity. In this article, the computational fluid dynamics method and experimental tests are employed to analyse its flow characteristics and pressure distribution. The results indicate that the pressure difference between the windward side and the leeward side of the cylinder is raised in view of it blocking the flow field. Four whirl vortexes are formed in four outlets of two wedge-shaped areas between the front part of the cylindrical surface and adjacent walls for the cylinder of L/ D = 1.5 at Re = 4.5 × 103. Vortex shedding is found in the direction of cylinder axis at Re = 4.5 × 104. The relationship between drag coefficient and Reynolds number is illustrated, obviously higher than that of the two-dimensional cylinder in open space.

Dynamics of Rolling-Element Bearings—Part I: Cylindrical Roller Bearing Analysis

1979 ◽  
Vol 101 (3) ◽  
pp. 293-302 ◽  
Author(s):  
P. K. Gupta
Keyword(s):  
Differential Equations ◽  
Normal Force ◽  
Equations Of Motion ◽  
Roller Bearing ◽  
Rolling Element Bearings ◽  
Analytical Formulation ◽  
Rolling Element ◽  
Cylindrical Roller Bearing ◽  
Cylindrical Roller ◽  
Bearing Analysis

An analytical formulation for the roller motion in a cylindrical roller bearing is presented in terms of the classical differential equations of motion. Roller-race interaction is analyzed in detail and the resulting normal force and moment vectors are determined. Elastohydrodynamic traction models are considered in determining the roller-race tractive forces and moments. Formulation for the roller end and race flange interaction during skewing of the roller is also considered. Roller-cage interactions are assumed to be either hydrodynamic or fully metallic. Simple relationships are used to determine the churning and drag losses.

scholarly journals Experimental Study on the Skidding Damage of a Cylindrical Roller Bearing

Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4075 ◽  
Author(s):  
Qing Zhang ◽  
Jun Luo ◽  
Xiang-yu Xie ◽  
Jin Xu ◽  
Zhen-huan Ye
Keyword(s):  
High Speed ◽  
Large Scale ◽  
Failure Modes ◽  
Roller Bearing ◽  
Weight Ratio ◽  
Operating Conditions ◽  
Roller Bearings ◽  
Light Load ◽  
Cylindrical Roller Bearing ◽  
Cylindrical Roller

As large-scale rotating machines develop toward high rotating speed and high power–weight ratio, skidding damage has become one of the major initial failure modes of cylindrical roller bearings. Therefore, understanding the skidding damage law is an effective way to ensure the safety of machines supported by cylindrical roller bearings. To realize the skidding damage, a high-speed rolling bearing test rig that can simulate the actual operating conditions of aviation bearings was used in this paper, and the skidding damage dynamic behaviors of cylindrical roller bearings were investigated. In addition, to ensure the accuracy of the obtained skidding damage mechanism, the cylindrical roller bearing was carefully inspected by microscopic analysis when the skidding damage occurred. Out results show that instantaneous increases in friction torque, vibration acceleration, and temperature are clearly observed when the skidding damage occurs in the cylindrical roller bearing. Furthermore, under the conditions of inadequate lubrication and light load, the critical speed of skidding damage is rather low. The major wear mechanisms of skidding damage include oxidation wear, abrasive wear, and delamination wear. The white layers are found locally in the inner ring and rollers under the actions of friction heat and shear force.

scholarly journals Study regarding the structural response of standard cylindrical roller bearings using ANSYS and MESYS

2018 ◽  
Vol 178 ◽  
pp. 05012
Author(s):  
Alin Marian Puşcaşu ◽  
Octavian Lupescu ◽  
Ana Bădănac
Keyword(s):  
Roller Bearing ◽  
Structural Response ◽  
Model System ◽  
Solid Model ◽  
Post Processing ◽  
Single Row ◽  
Roller Bearings ◽  
Cylindrical Roller Bearing ◽  
Cylindrical Roller ◽  
Prototype Design

Bearings are manufactured in a wide variety of types and sizes especially with a single row of rollers, two rows of rollers or more, with cages or roller beside roller. Researches carried out by authors in this paper have followed a comparative analysis between a standard cylindrical roller bearings design and a prototype design using finite element method software's like ANSYS and MESYS. ANSYS is commonly used and enjoyed by an extended use in the structural areas, for analysis. ANSYS it consists of three main phases: Pre-processing, conducting or importing of the solid model system that are to be analyzed, solid meshing design in finite elements, implementation of conditions and loads at the limit, Processing, numeric solving of the characteristic equations behavior of the system and getting the solution, Post-processing, viewing the results in order to analyses system reaction and identification of areas with critical applications. The purpose of the study was to collect data's using two different software's and after to compare them with mathematical results. Using the ANSYS in this purpose it was able to analyses the design of the structure of the cylindrical roller bearing in detail.

scholarly journals Direct load monitoring of rolling bearing contacts using ultrasonic time of flight

2015 ◽  
Vol 471 (2180) ◽  
pp. 20150103 ◽  
Author(s):  
W. Chen ◽  
R. Mills ◽  
R. S. Dwyer-Joyce
Keyword(s):  
Roller Bearing ◽  
Time Of Flight ◽  
Ultrasonic Pulse ◽  
Ultrasonic Time ◽  
Rolling Element ◽  
Bearing Load ◽  
Load Monitoring ◽  
Rolling Elements ◽  
Cylindrical Roller Bearing ◽  
Cylindrical Roller

The load applied by each rolling element on a bearing raceway controls friction, wear and service life. It is possible to infer bearing load from load cells or strain gauges on the shaft or bearing housing. However, this is not always simply and uniquely related to the real load transmitted by rolling elements directly to the raceway. Firstly, the load sharing between rolling elements in the raceway is statically indeterminate, and secondly, in a machine with non-steady loading, the load path is complex and highly transient being subject to the dynamic behaviour of the transmission system. This study describes a method to measure the load transmitted directly by a rolling element to the raceway by using the time of flight (ToF) of a reflected ultrasonic pulse. A piezoelectric sensor was permanently bonded onto the bore surface of the inner raceway of a cylindrical roller bearing. The ToF of an ultrasonic pulse from the sensor to the roller–raceway contact was measured. This ToF depends on the speed of the wave and the thickness of the raceway. The speed of an ultrasonic wave changes with the state of the stress, known as the acoustoelastic effect. The thickness of the material varies when deflection occurs as the contacting surfaces are subjected to load. In addition, the contact stiffness changes the phase of the reflected signal and in simple peak-to-peak measurement, this appears as a change in the ToF. In this work, the Hilbert transform was used to remove this contact dependent phase shift. Experiments have been performed on both a model line contact and a single row cylindrical roller bearing from the planet gear of a wind turbine epicyclic gearbox. The change in ToF under different bearing loads was recorded and used to determine the deflection of the raceway. This was then related to the bearing load using a simple elastic contact model. Measured load from the ultrasonic reflection was compared with the applied bearing load with good agreement. The technique shows promise as an effective method for load monitoring in real-world bearing applications.

Dynamics of Rolling-Element Bearings—Part II: Cylindrical Roller Bearing Results

1979 ◽  
Vol 101 (3) ◽  
pp. 305-311 ◽  
Author(s):  
P. K. Gupta
Keyword(s):  
Differential Equations ◽  
Power Loss ◽  
Equations Of Motion ◽  
Roller Bearing ◽  
Geometrical Parameters ◽  
Rolling Element Bearings ◽  
Rolling Element ◽  
Cylindrical Roller Bearing ◽  
Cylindrical Roller ◽  
General Motion

Cylindrical roller bearing performance simulations are expressed in terms of the general motion of the bearing elements as derived by integrating the differential equations of motion. Roller skew as induced by relative race misalignment is simulated. It is shown that skidding can be reduced by using a lubricant providing relatively high traction. However, such a fluid results in increased bearing torque and power loss. The influence of geometrical parameters, such as roller/cage, or race/cage clearance and radial preload, on the roller and cage motion is also investigated.

Modal and harmonic response analysis of a rolling bearing coupled by rigid and flexible materials

2019 ◽  
Vol 9 (9) ◽  
pp. 1017-1024
Author(s):  
Jianghong Yu ◽  
Lei Xiang ◽  
Wen Yang ◽  
Chao Li ◽  
Yaoyao Deng ◽  
...  
Keyword(s):  
Structural Parameters ◽  
Excitation Frequency ◽  
Roller Bearing ◽  
Response Analysis ◽  
Harmonic Response ◽  
Flexible Materials ◽  
Roller Bearings ◽  
Elastic Composite ◽  
Cylindrical Roller Bearing ◽  
Cylindrical Roller

Elastic composite cylindrical roller bearing is a new type of rolling bearings. Its rolling body is composed of rigid and flexible materials. In order to investigate the modal characteristics and harmonic response rules of the elastic composite cylindrical roller bearings with different structural parameters, we computed the modal solutions of a cylindrical roller bearing and the elastic composite cylindrical roller bearings with filling degrees of 40%, 50% and 65%, and determined the scope of the excitation frequency according to the computed first twelve orders of the modal frequency. On this basis, we analyzed the steady-state response under a sinusoidal alternating load as well as the vibration conditions of the elastic composite cylindrical roller bearings with different filling degrees within the excitation scope, and explored the relationship between the responses such as displacement and stress and the excitation frequency. The results showed that the natural frequencies of the elastic composite cylindrical roller bearings with filling degrees of 40% and 50% were similar to that of a solid bearing, while that of the elastic composite cylindrical roller bearings with a filling degree of 65% was relatively smaller than that of a solid bearing. The vibration modes of the bearings mainly manifested as bending and torsional deformation of the inner rings. Under the action of an excitation load, the peak responses of the bearings occurred near the fifth and sixth orders of the natural frequency. This research can provide a theoretical reference for the optimal design and engineering applications of the elastic composite cylindrical roller bearings.

Aim Investigation of the Axial Load Carrying Capacity of Cylindrical Roller Bearings

1973 ◽  
Vol 187 (1) ◽  
pp. 763-770 ◽  
Author(s):  
C. M. Taylor
Keyword(s):  
Axial Load ◽  
Roller Bearing ◽  
Axial Loading ◽  
Significant Feature ◽  
Axial Loads ◽  
Roller Bearings ◽  
Load Carrying ◽  
Rolling Elements ◽  
Cylindrical Roller Bearing ◽  
Cylindrical Roller

Normally cylindrical roller bearings are employed to transmit purely radial loads. However, depending upon the configuration of lips or flanges on the rings, it is sometimes possible to carry an axial load. In certain applications, an axial load capability is essential. A significant feature in determining the performance of a cylindrical roller bearing under axial loading is the lubrication conditions existing between the lips and rolling elements. The paper describes a study of such conditions. The long-term aim of the work is to provide a basis for the design of cylindrical roller bearings to carry axial loads.

Measurement of Oil Film Thickness in Cylindrical Roller Bearing by Ultrasound

2014 ◽  
Author(s):  
Kai Zhang ◽  
Qingfeng Meng ◽  
Wei Zhao
Keyword(s):  
Reflection Coefficient ◽  
Film Thickness ◽  
Roller Bearing ◽  
Piezoelectric Element ◽  
Elastohydrodynamic Lubrication ◽  
Spring Model ◽  
Oil Film ◽  
Rolling Element ◽  
Cylindrical Roller Bearing ◽  
Cylindrical Roller

This paper describes the measurement of oil film thickness between rolling element and inner raceway in cylindrical roller bearing. A fine piezoelectric element is bonded on the inner surface of the inner ring to measure the reflection coefficient of oil between rolling element and inner raceway. The quasi-static spring model is used to calculate oil film thickness from the corrected reflection coefficient data. Experiments are described on a simplified cylindrical roller bearing configured by one cylindrical roller, 11ø, and an inner ring from a NU209EM bearing. Reasonable agreement is shown over several loads and speeds with predictions from elastohydrodynamic lubrication (EHL) theory.

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