The Influence of Temperature and Metal Pairs on the Scuffing of a Commercial Oil

1973 ◽  
Vol 187 (1) ◽  
pp. 757-761 ◽  
Author(s):  
M. W. Bailey ◽  
A. Cameron
Keyword(s):  
Film Thickness ◽  
High Speed ◽  
Extreme Pressure ◽  
Temperature Behaviour ◽  
Slow Speed ◽  
Influence Of Temperature ◽  
Minimum Film Thickness ◽  
Friction Temperature ◽  
Failure Temperature ◽  
Commercial Oil

A modified type of 4-ball machine—a ball running on three asymmetrically placed pegs—allows the scuffing behaviour of a commercial extreme pressure lubricant to be investigated. Particular emphasis has been placed on the reactivity of the steels used as test specimens and their position relative to the contact. The constant failure temperature hypothesis is found to be obeyed only under certain well defined conditions. It is shown that the friction-temperature behaviour measured at slow speed can be correlated with scuffing results at high speed. Little evidence is found to support the minimum film thickness failure criterion.

The Influence of Temperature and Metal Pairs on the Scuffing of a Commercial Oil

1973 ◽  
Vol 187 (1) ◽  
pp. 757-761 ◽  
Author(s):  
M. W. Bailey ◽  
A. Cameron
Keyword(s):  
Film Thickness ◽  
High Speed ◽  
Extreme Pressure ◽  
Temperature Behaviour ◽  
Slow Speed ◽  
Influence Of Temperature ◽  
Minimum Film Thickness ◽  
Friction Temperature ◽  
Failure Temperature ◽  
Commercial Oil

A modified type of 4-ball machine—a ball running on three asymmetrically placed pegs—allows the scuffing behaviour of a commercial extreme pressure lubricant to be investigated. Particular emphasis has been placed on the reactivity of the steels used as test specimens and their position relative to the contact. The constant failure temperature hypothesis is found to be obeyed only under certain well defined conditions. It is shown that the friction-temperature behaviour measured at slow speed can be correlated with scuffing results at high speed. Little evidence is found to support the minimum film thickness failure criterion.

Grease soap particles passing through an elastohydrodynamic contact under side slip conditions

2000 ◽  
Vol 214 (4) ◽  
pp. 317-325 ◽  
Author(s):  
P Eriksson ◽  
V Wikström ◽  
R Larsson
Keyword(s):  
Film Thickness ◽  
High Speed ◽  
Previous Investigation ◽  
Video Camera ◽  
Slip Conditions ◽  
High Speed Video ◽  
Elastohydrodynamic Contact ◽  
High Speed Video Camera ◽  
Pure Rolling ◽  
Minimum Film Thickness

In a previous investigation, grease thickener fibres were tracked as they passed through an elastohydrodynamic (EHD) contact in pure rolling using interferometry in a standard ball-and-disc apparatus. In order to capture single thickener fibres, a high-speed video camera was used. Here, the experiments have been repeated introducing different amounts of side slip for different rolling speeds and a faster video camera capable of capturing 4500 frames/s. The contact was lubricated with a continuous supply of grease. Two greases, based on the same synthetic poly(α-olefin) but thickened with Li-12-OH and lithium complex soap respectively, were studied. It was observed that the thickener fibres were stretched both before entering the contact and as they passed through it. Fibres seem to avoid the minimum film thickness regions and, if they enter, the film is restored immediately after passage.

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.

Research on Dual-Cones CVT Based on EHL

2011 ◽  
Vol 308-310 ◽  
pp. 1929-1934
Author(s):  
Hui Li Dong ◽  
Shi Hua Yuan ◽  
Chao Wei
Keyword(s):  
Film Thickness ◽  
High Speed ◽  
Power Transmission ◽  
Elastohydrodynamic Lubrication ◽  
Face To Face ◽  
Dual Cones ◽  
Higher Power ◽  
Minimum Film Thickness ◽  
Traction Coefficient ◽  
Increasing Load

A novel configuration of CVT that contains two cones located in the same shaft face to face is researched about the traction performance under high speed based on the theory of elastohydrodynamic lubrication(EHL). The effects of load, radii of curvature and slip-roll ratio on the traction characteristics and power transmission are analyzed. The results show that with increasing load the traction coefficient enhances close to linearly where the load is not heavy and the minimum film thickness decreases linearly when the inner wheel radii of curvature less than 0.085m. The leftmost position could transmit higher power. The power transmitted improves slightly as slip-roll ratio enhances in an appropriate range.

Design of Efficient Turbulent Thrust Bearings

1977 ◽  
Vol 99 (1) ◽  
pp. 113-121
Author(s):  
D. F. Wilcock
Keyword(s):  
High Temperature ◽  
Film Thickness ◽  
Temperature Rise ◽  
Power Loss ◽  
High Speed ◽  
Thrust Bearings ◽  
Higher Power ◽  
Minimum Film Thickness ◽  
Oil Flow ◽  
High Temperature Rise

Turbulence makes high speed conventionally designed bearings operate with higher power loss, high temperature rise, and lower oil flow than predicted. The objective of this paper is to show that the phenomenon of turbulence can be turned to the designer’s and operator’s advantage; and that turbulent thrust bearings can be designed to operate with lower power loss than conventional design would predict, while maintaining the same minimum film thickness and safe temperature rise.

Predictive tool for frictional performance of piston ring-pack/liner conjunction

2019 ◽  
Vol 13 (3) ◽  
pp. 5513-5527
Author(s):  
J. W. Tee ◽  
S. H. Hamdan ◽  
W. W. F. Chong
Keyword(s):  
Film Thickness ◽  
Mathematical Models ◽  
Piston Ring ◽  
Published Data ◽  
Predictive Tool ◽  
Frictional Losses ◽  
Fundamental Understanding ◽  
Minimum Film Thickness ◽  
Piston Ring Pack ◽  
Ring Pack

Fundamental understanding of piston ring-pack lubrication is essential in reducing engine friction. This is because a substantial portion of engine frictional losses come from piston-ring assembly. Hence, this study investigates the tribological impact of different piston ring profiles towards engine in-cylinder friction. Mathematical models are derived from Reynolds equation by using Reynolds’ boundary conditions to generate the contact pressure distribution along the complete piston ring-pack/liner conjunction. The predicted minimum film thickness is then used to predict the friction generated between the piston ring-pack and the engine cylinder liner. The engine in-cylinder friction is predicted using Greenwood and Williamson’s rough surface contact model. The model considers both the boundary friction and the viscous friction components. These mathematical models are integrated to simulate the total engine in-cylinder friction originating from the studied piston ring-pack for a complete engine cycle. The predicted minimum film thickness and frictional properties from the current models are shown to correlate reasonably with the published data. Hence, the proposed mathematical approach prepares a simplistic platform in predicting frictional losses of piston ring-pack/liner conjunction, allowing for an improved fundamental understanding of the parasitic losses in an internal combustion engine.

Sinusoidal Three-Lobe Bearings—Optimization and Stability Charts

1980 ◽  
Vol 102 (4) ◽  
pp. 416-424 ◽  
Author(s):  
W. E. ten Napel ◽  
R. Bosma
Keyword(s):  
Film Thickness ◽  
Stability Parameters ◽  
Stability Regions ◽  
Damping Coefficients ◽  
Optimum Position ◽  
Minimum Film Thickness ◽  
Stiffness And Damping

In contradistinction to the commonly used segmented three-lobe bearing, another type of bearing, i.e., the sinusoidal three-lobe bearing has been investigated in this paper. The main advantage of this bearing is that it can very easily be manufactured. Special attention has been paid to problems of optimization with regard to minimum film thickness and friction, respectively. Stiffness and damping coefficients have been calculated as well as stability regions and stability parameters. Additionally, the optimum position of the oil grooves has been 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.

Influence of Surface Waviness on the Thermal Elastohydrodynamic Lubrication of an Eccentric-Tappet Pair

2013 ◽  
Vol 135 (2) ◽  
Author(s):  
J. Wang ◽  
C. H. Venner ◽  
A. A. Lubrecht
Keyword(s):  
Film Thickness ◽  
Elastohydrodynamic Lubrication ◽  
Surface Waviness ◽  
Film Pressure ◽  
Oil Film ◽  
Working Cycle ◽  
Temperature Oscillations ◽  
Minimum Film Thickness ◽  
Traction Coefficient ◽  
Oil Film Pressure

The effect of single-sided and double-sided harmonic surface waviness on the film thickness, pressure, and temperature oscillations in an elastohydrodynamically lubricated eccentric-tappet pair has been investigated in relation to the eccentricity and the waviness wavelength. The results show that, during one working cycle, the waviness causes significant fluctuations of the oil film, pressure, and temperature, as well as a reduction in minimum film thickness. Smaller wavelength causes more dramatic variations in oil film. The fluctuations of the pressure, film thickness, temperature, and traction coefficient caused by double-sided waviness are nearly the same compared with the single-sided waviness, but the variations are less intense.

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