Influence of Scratches on the Performance of a Partial Journal Bearing

2008 ◽  
Author(s):  
Mihai B. Dobrica ◽  
Michel Fillon
Keyword(s):  
Film Thickness ◽  
Thermal Effects ◽  
Journal Bearing ◽  
Friction Torque ◽  
Maximum Pressure ◽  
Relative Depth ◽  
Performance Loss ◽  
Minimum Film Thickness ◽  
Overall Performance ◽  
Bearing Damage

In this paper, the influence of circumferential scratches on the thermohydrodynamic performance of a partial (lobe) journal bearing is studied. The bearing damage is characterized by four factors: the area of the scratched region, the density of the scratches within the affected area, the relative position of the scratched region and the relative depth of the wear defects. The bearing performance is characterized by minimum film thickness, average oil temperature, maximum pressure, friction torque etc., at imposed magnitude and direction of the load. A numerical hydrodynamic model with global thermal effects is used for studying the influence of the different wear related parameters on the bearing performance. The results permit to predict the overall performance loss due to the circumferential wear marks, for different wear profiles. The types of wear profiles that can lead to the bearing destruction (characterized by a critical minimum film thickness) are also investigated.

Dynamic Analysis of Tilting-Pad Journal Bearing—Influence of Pad Deformations

1994 ◽  
Vol 116 (3) ◽  
pp. 621-627 ◽  
Author(s):  
H. Desbordes ◽  
M. Fillon ◽  
C. Chan Hew Wai ◽  
J. Frene
Keyword(s):  
Film Thickness ◽  
Pressure Field ◽  
Journal Bearing ◽  
Maximum Pressure ◽  
Tilting Pad ◽  
Minimum Film Thickness ◽  
Dimensional Finite Element ◽  
The One ◽  
Tilting Pad Journal Bearing ◽  
Tilting Pad Journal Bearings

A theoretical nonlinear analysis of tilting-pad journal bearings is presented for small and large unbalance loads under isothermal conditions. The radial displacements of internal pad surface due to pressure field are determined by a two-dimensional finite element method in order to define the actual film thickness. The influence of pad deformations on the journal orbit, on the minimum film thickness and on the maximum pressure is studied. The effects of pad displacements are to decrease the minimum film thickness and to increase the maximum pressure. The orbit amplitude is also increased by 20 percent for the large unbalance load compared to the one obtained for rigid pad.

An Experimental Analysis of Misalignment Effects on Hydrodynamic Plain Journal Bearing Performances

2001 ◽  
Vol 124 (2) ◽  
pp. 313-319 ◽  
Author(s):  
J. Bouyer ◽  
M. Fillon
Keyword(s):  
Film Thickness ◽  
Journal Bearing ◽  
Hydrodynamic Pressure ◽  
Operating Conditions ◽  
Temperature Fields ◽  
Maximum Pressure ◽  
Minimum Film Thickness ◽  
Oil Flow ◽  
Hydrodynamic Effects

The present study deals with the experimental determination of the performance of a 100 mm diameter plain journal bearing submitted to a misalignment torque. Hydrodynamic pressure and temperature fields in the mid-plane of the bearing, temperatures in two axial directions, oil flow rate, and minimum film thickness, were all measured for various operating conditions and misalignment torques. Tests were carried out for rotational speeds ranging from 1500 to 4000 rpm with a maximum static load of 9000 N and a misalignment torque varying from 0 to 70 N.m. The bearing performances were greatly affected by the misalignment. The maximum pressure in the mid-plane decreased by 20 percent for the largest misalignment torque while the minimum film thickness was reduced by 80 percent. The misalignment caused more significant changes in bearing performance when the rotational speed or load was low. The hydrodynamic effects were then relatively small and the bearing offered less resistance to the misalignment.

scholarly journals Sensibility Analysis of Design Parameters for Journal Bearings Optimization of Mass Balancing Systems

2005 ◽  
Author(s):  
L. Morais ◽  
L. A. Ferreira
Keyword(s):  
Film Thickness ◽  
Power Loss ◽  
Journal Bearing ◽  
Journal Bearings ◽  
Radial Clearance ◽  
Maximum Pressure ◽  
Minimum Film Thickness ◽  
Mass Balancing ◽  
Sensibility Analysis ◽  
Selection Of

This work presents a sensibility analysis for the journal bearings of combustion engines mass balancing systems. Applying it, it’s possible to improve the journal bearings and avoid possible failures. This analysis consists on studying the effects of the variation of the journal bearings main parameters (radial clearance, journal bearing diameter and journal bearing length) on the journal bearings operating conditions (minimum film thickness, maximum pressure and power loss). The analysis also includes the comparison and selection of the different metallic materials that can be used in these journal bearings, as well as the selection of the lubrication system groove suitable for the journal bearings used in this kind of application. This sensibility analysis shows that: increasing the radial clearance the minimum film thickness increases, the maximum pressure remains approximately the same and the power loss decreases; increasing the journal bearing length, the minimum film thickness and power loss increase and the maximum pressure decreases; increasing the journal bearing diameter, the minimum film thickness and power loss increase and the maximum pressure decreases. At last, it’s found that the white metals (Babbitts) are considered the most advantageous and indicated materials for these journal bearings, and that the lubrication system grooves should be circumferential.

A Global Approach of Thermal Effects Including Pad Deformations in Tilting-Pad Journal Bearings Submitted to Unbalance Load

1996 ◽  
Vol 118 (1) ◽  
pp. 169-174 ◽  
Author(s):  
M. Fillon ◽  
H. Desbordes ◽  
J. Freˆne ◽  
C. Chan Hew Wai
Keyword(s):  
Thermal Effects ◽  
Journal Bearing ◽  
Great Influence ◽  
Maximum Pressure ◽  
Time Interval ◽  
Tilting Pad ◽  
Minimum Film Thickness ◽  
Tilting Pad Journal Bearing ◽  
Tilting Pad Journal Bearings ◽  
Theoretical Results

The purpose of this paper is to study the response of a tilting-pad journal bearing submitted to an unbalance load. A pseudo-time transient analysis has been developed taking into account the effective viscosity of the lubricant, the thermal expansion of bearing elements, and the elastic pad deformations. At each time interval, and for each pad, an effective temperature of the film is deduced from an energy balance. First, a comparison between theoretical results and experimental data is presented for a four-shoe tilting-pad journal bearing subjected to a static load. Second, the influence of the thermal and pad flexibility effects on the journal center orbit, on the minimum film thickness and on the maximum pressure is studied for various unbalance loads. Both the viscosity variation and the operating clearances due to elastic and thermal deformations of the bearing elements have a great influence on the behavior of the bearing.

Influence of Deformation Effects on a Misaligned Plain Journal Bearing

2005 ◽  
Author(s):  
J. Bouyer ◽  
M. Fillon
Keyword(s):  
Film Thickness ◽  
Thermal Effects ◽  
Thermal Deformation ◽  
Journal Bearing ◽  
Operating Conditions ◽  
Minimum Film Thickness

Bearings nowadays are often subjected to misalignment. Both theoretical and experimental misaligned bearings have been previously studied, it being found that the minimum film thickness is the parameter which is most noticeably affected. However, other work has showed that both thermal and deformation effects have to be considered when a bearing is subjected to severe operating conditions. The present work analyzes the influence of thermal effects, as well as the effects of mechanical and thermal deformation on misaligned bearing performance.

Comprehensive design methodology for an engine journal bearing

2000 ◽  
Vol 214 (4) ◽  
pp. 401-412 ◽  
Author(s):  
H Hirani ◽  
K Athre ◽  
S Biswas
Keyword(s):  
Film Thickness ◽  
High Speed ◽  
Design Methodology ◽  
Design Procedure ◽  
Maximum Pressure ◽  
Connecting Rod ◽  
Automotive Engine ◽  
Reciprocating Engine ◽  
High Power Output ◽  
Minimum Film Thickness

The trend towards high power output, high speed and low power loss in engines requires a better understanding of bearing behaviour. Research in this area is directed more towards different aspects involved in bearing analyses, rather than providing a comprehensive guideline on design of bearing. This effort compiles the design methodology for selection of diametral clearance and bearing length by limiting the minimum film thickness, maximum pressure and temperature. The design procedure is summarized on the basis of the existing rapid bearing analyses for evaluation of the journal trajectory, minimum film thickness and maximum pressure and simplified thermal analysis. A flow chart is provided for step-by-step bearing design. Finally, two case studies of engine bearings are described: one investigates the VEB bigend connecting-rod bearing for a large industrial reciprocating engine and the other a main crankshaft bearing for an automotive engine. The methodology translates into easy-to-use expressions and the overall procedure is outlined, using practical data to demonstrate how this can be employed effectively by users.

Thermal Non-Newtonian EHL Analysis of Rib-Roller End Contact in Tapered Roller Bearings

1995 ◽  
Vol 117 (4) ◽  
pp. 646-654 ◽  
Author(s):  
Xiaofei Jiang ◽  
Pat Lam Wong ◽  
Zhiming Zhang
Keyword(s):  
Film Thickness ◽  
Surface Temperature ◽  
Thermal Effects ◽  
Friction Torque ◽  
Curvature Radius ◽  
Roller Bearings ◽  
Tapered Roller ◽  
Tapered Roller Bearings ◽  
Full Consideration ◽  
Newtonian Behavior

An EHL approach to the rib-roller end contact in tapered roller bearings has been achieved by taking into account the non-Newtonian behavior of lubricants and thermal effects and with full consideration of the peculiar geometrical and kinematic conditions. Two kinds of geometrical configurations of rib and roller end were investigated: tapered rib/spherical roller end and spherical rib/spherical roller end. Optimal ratios of curvature radius of roller end to rib face were deduced. The film thickness, friction torque, lubricant temperature, and surface temperature at various speeds and loads were calculated.

On the Significance of Thermal and Deformation Effects on a Plain Journal Bearing Subjected to Severe Operating Conditions

2004 ◽  
Vol 126 (4) ◽  
pp. 819-822 ◽  
Author(s):  
J. Bouyer ◽  
M. Fillon
Keyword(s):  
Thermal Effects ◽  
Journal Bearing ◽  
Operating Conditions ◽  
Maximum Temperature ◽  
Maximum Pressure ◽  
Thermal Deformations ◽  
Performance Predictions ◽  
Accurate Performance ◽  
Global And Local ◽  
Highly Loaded

The present work analyzes the influence of global and local thermal effects and also mechanical and thermal deformations on bearing performance. Local thermal effects are important in the case of a highly loaded bearing because these effects are concentrated within a small zone of the bearing. The thermoelastohydrodynamic study, including deformations due to pressure, leads to a significant decrease in maximum pressure and a slight decrease in maximum temperature. For accurate performance predictions of bearings operating under severe conditions, numerical simulations have to take into account local thermal effects and both mechanical and thermal deformations.

Effect of oil starvation on the isothermal impact problem

2017 ◽  
Vol 232 (10) ◽  
pp. 1332-1339
Author(s):  
Duohuan Wu ◽  
Jing Wang ◽  
Peiran Yang ◽  
Ton Lubrecht
Keyword(s):  
Film Thickness ◽  
Pressure Gradient ◽  
Thickness Distribution ◽  
Elastohydrodynamic Lubrication ◽  
Maximum Pressure ◽  
Numerical Techniques ◽  
Minimum Film Thickness ◽  
The Impact ◽  
Impact Motion ◽  
Impact Problem

In this study, the effect of oil starvation on isothermal elastohydrodynamic lubrication of an impact motion is explored with the aid of numerical techniques. During the impact process, on comparison with the fully lubricated results, the pressure and film thickness are much lower and the entrapped film shape does not happen. The rebound is delayed by the oil starvation assumption. During the rebound process, a periphery entrapment is seen in the starved film thickness distribution. Under the starved condition, the maximum pressure gradient is higher. The central film thickness and minimum film thickness exhibit different variations compared with the results by fully flooded assumption.

scholarly journals Lubrication and frictional analysis of cam–roller follower mechanisms

2017 ◽  
Vol 232 (3) ◽  
pp. 347-363 ◽  
Author(s):  
Shivam S Alakhramsing ◽  
Matthijn de Rooij ◽  
Dirk Jan Schipper ◽  
Mark van Drogen
Keyword(s):  
Film Thickness ◽  
Finite Length ◽  
Power Loss ◽  
Fuel Injection ◽  
Contact Forces ◽  
Injection System ◽  
Maximum Pressure ◽  
Line Contact ◽  
Power Losses ◽  
Minimum Film Thickness

In this work, a full numerical solution to the cam–roller follower-lubricated contact is provided. The general framework of this model is based on a model describing the kinematics, a finite length line contact isothermal-EHL model for the cam–roller contact and a semi-analytical lubrication model for the roller–pin bearing. These models are interlinked via an improved roller–pin friction model. For the numerical study, a cam–roller follower pair, as part of the fuel injection system in Diesel engines, was analyzed. The results, including the evolution of power losses, minimum film thickness and maximum pressures, are compared with analytical solutions corresponding to infinite line contact models. The main findings of this work are that for accurate prediction of crucial performance indicators such as minimum film thickness, maximum pressure and power losses a finite length line contact analysis is necessary due to non-typical EHL characteristics of the pressure and film thickness distributions. Furthermore, due to the high contact forces associated with cam–roller pairs as part of fuel injection units, rolling friction is the dominant power loss contributor as roller slippage appears to be negligible. Finally, the influence of the different roller axial surface profiles on minimum film thickness, maximum pressure and power loss is shown to be significant. In fact, due to larger contact area, the maximum pressure can be reduced and the minimum film thickness can be increased significantly, however, at the cost of higher power losses.

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