Lubrication Review: Developments in Bearings and Lubricants—A Digest of the Literature From 1961–1962

1964 ◽  
Vol 86 (2) ◽  
pp. 367-386
Author(s):  
R. P. Shevchenko ◽  
G. S. Reichenbach ◽  
M. Roberts ◽  
E. Kingsbury ◽  
Dimiter Ramadanoff ◽  
...  
Keyword(s):  
Friction And Wear ◽  
Theoretical Work ◽  
Corrective Action ◽  
Fluid Film ◽  
Rolling Element Bearings ◽  
Basic Work ◽  
Rolling Element ◽  
Work Done ◽  
Film Lubrication

This 1961–1962 lubrication digest reviews developments in fluid-film and rolling-element bearings, lubrication for bearings, gears, and automobiles; and covers basic work done in the general areas of friction and wear; elastohydrodynamic, boundary, and full film lubrication; and lubricant properties. The authors cover specific areas of lubrication literature and it is recommended that the reader, even the specialist, peruse related areas since the years of effort in this field have exposed more of the fundamentals; and the conclusious drawn, and the basic laws formulated in one area are important to all areas. It is wistfully hoped that the digest will disclose disproportionate effort because of funding and imbalance between empirical and theoretical work and spur corrective action.

Lubrication Review: Developments in Bearings and Lubricants—a Digest of the Literature From 1962–1963

1964 ◽  
Vol 86 (4) ◽  
pp. 883-906
Author(s):  
D. F. Hays ◽  
J. D. McHugh ◽  
E. E. Klaus ◽  
W. J. Wojtowicz ◽  
H. A. Hartung ◽  
...  
Keyword(s):  
Boundary Lubrication ◽  
Friction And Wear ◽  
Essential Elements ◽  
Theory And Practice ◽  
Experimental Investigations ◽  
Rolling Element Bearings ◽  
Rolling Element ◽  
Recent Developments ◽  
Film Lubrication ◽  
Fluid Film Lubrication

The 1962–1963 Lubrication Review brings together information on publications relating to several aspects of the broad field of lubrication. Although it does not cover all of the significant domestic and foreign publications in this field, it does summarize many of the results of current theoretical and experimental investigations. It also indicates themes or patterns of current programs relating to lubrication. The review is more than a list of references since each reviewer has commented on the essential elements or results reported by the investigators. The areas reviewed include fluid-film lubrication, developments in lubricants, metalworking lubricants, automotive lubricants, gear lubrication, boundary lubrication, rolling element bearings, and friction and wear. It is hoped that those who are currently involved in these specific areas will find the review helpful in summarizing recent developments in these areas and that those who are interested in extending their knowledge of lubrication theory and practice might find the review to be a helpful guide.

Rolling Element Bearing Monitoring and Diagnostics Techniques

1989 ◽  
Vol 111 (2) ◽  
pp. 251-256 ◽  
Author(s):  
R. G. Harker ◽  
J. L. Sandy
Keyword(s):  
Case Studies ◽  
Fluid Film ◽  
Rolling Element Bearing ◽  
Rolling Element Bearings ◽  
Film Type ◽  
Rolling Element ◽  
Element Bearing ◽  
Monitoring And Diagnostics ◽  
Bearing Monitoring

Rolling element bearings require distinctly different techniques for monitoring and diagnostics from those used for fluid-film type bearings. A description of these techniques and the instrumentation used to acquire the necessary data is provided for comparison. Also included are some case studies to illustrate how these techniques are applied.

Transient Forward and Backward Whirl of Beam and Solid Rotors With Stiffening and Softening Effects

2011 ◽  
Author(s):  
J. S. Rao
Keyword(s):  
Cross Section ◽  
Variable Cross Section ◽  
Fluid Film ◽  
Variable Cross ◽  
Rolling Element Bearings ◽  
Unbalance Response ◽  
Beam Analysis ◽  
Rolling Element ◽  
Backward Whirl ◽  
Rotor Model

This paper describe the procedure of achieving unbalance response and stability of general accelerating solid rotor model rotors with variable cross-section on fluid film or rolling element bearings and seals with the casings mounted on foundations including stress stiffening and spin softening effects. The solid rotor analysis results are verified with beam analysis results wherever applicable.

scholarly journals There’s the Rub

2009 ◽  
Vol 131 (01) ◽  
pp. 41-45
Author(s):  
James G. Skakoon
Keyword(s):  
High Performance ◽  
Friction And Wear ◽  
Mechanical Design ◽  
Rolling Element Bearings ◽  
Dynamic Coefficients ◽  
Design Engineers ◽  
Rolling Element ◽  
Practical Guidelines ◽  
System Properties ◽  
Induced Changes

This article reviews the mechanical design and a set of practical guidelines for design engineers. Engineers have plenty of technology for controlling friction and wear, including naturally lubricious materials, high-performance lubricants, and rolling element bearings. But where friction is concerned, good mechanical design starts with guidelines. Friction changes with time, reflecting sliding-induced changes to the interface. The traditional single static and single dynamic coefficients of friction are misleading because they do not reflect fluctuations and transitions in friction. The friction coefficient, static or dynamic, has no single, unique value for a given material pair, but rather is a characteristic of those materials when rubbed together under specific conditions. Friction and wear are not material properties; they are system properties. So many test protocols, such as thrust washer tests, will give one result, but actual systems will have different results.

Reliability Improvement of Rotor Supports by Combining Rolling-Element Bearings and Fluid-Film Bearings

2014 ◽  
Vol 630 ◽  
pp. 188-198 ◽  
Author(s):  
Roman Polyakov ◽  
Leonid Savin ◽  
Denis Shutin
Keyword(s):  
Load Capacity ◽  
Life Time ◽  
Performance Characteristics ◽  
Fluid Film ◽  
Rolling Element Bearing ◽  
Rolling Element Bearings ◽  
Advantages And Disadvantages ◽  
Fluid Film Bearings ◽  
Rolling Element ◽  
Unit Increase

Reliability of rotating machinery is determined to a considerable degree by the bearing units. For several applications the requirements in rotation speed, bearing load and maximal vibration level are so extreme that neither rolling-element bearings nor fluid-film bearings could provide necessary performance characteristics during all regimes of operation. Hybrid bearings, which are a combination of rolling-element and fluid-film bearings, can improve performance characteristics and reliability of the rotor-bearing systems. The aim of this work is to analyze the advantages and disadvantages of the hybrid bearings. Known real applications of hybrid bearings are discussed. Analysis shows that depending on the application different hybrid bearing types could improve dynamic characteristics and life time of the bearing unit, increase load capacity and DN limit of the rolling-element bearing.

Analysis of the conditions for the occurrence of the effect of a minimum of friction in hybrid bearings based on the load separation principle

2018 ◽  
Vol 233 (2) ◽  
pp. 271-280
Author(s):  
Roman Polyakov ◽  
Leonid Savin ◽  
Alex Fetisov
Keyword(s):  
Rolling Contact ◽  
Friction Reduction ◽  
Fluid Film ◽  
Rolling Element Bearing ◽  
Contact Friction ◽  
Rolling Element Bearings ◽  
Operating Characteristics ◽  
Fluid Film Bearings ◽  
Friction Regime ◽  
Rolling Element

Reliability of rotating machinery is determined to a considerable degree by the bearing units. For several applications the requirements in rotational speed, bearing load and maximal vibration level are so extreme that neither rolling-element bearings nor fluid-film bearings could provide necessary operating characteristics during all regimes of operation. Hybrid bearings, which are a combination of rolling-element and fluid-film bearings, can improve performance characteristics and reliability of the rotor-bearing systems. A hybrid bearing, where a rolling-element bearing and a fluid-film bearing are positioned parallel to the vector of external load (PLEX), has the following advantages compared to a single bearing, whether rolling-element or fluid-film one: increase of life expectancy, load capacity increase, friction reduction, thermal regime enhancement, increase of stiffness, and damping properties. The present paper presents the results of theoretical and numerical research of friction characteristics of PLEX in mixed sliding and rolling friction, i.e. combination of viscous and rolling contact friction, regime. The conditions of minimum friction effect occurrence have been substantiated, and rational relations between characteristics of hybrid rolling-element bearings and fluid-film bearings needed for provision of such effect have been experimentally proven. Finally, the paper presents recommendations regarding design of such hybrid bearings for heavily loaded bearing nodes of rolling mills.

Morton-Newkirk Effect in Overhung Rotor Supported in Rolling Element Bearings

2009 ◽  
Author(s):  
Thom M. Eldridge ◽  
Andrew Olsen ◽  
Michael Carney
Keyword(s):  
Temperature Rise ◽  
Fluid Film ◽  
Rolling Element Bearing ◽  
Viscous Heating ◽  
Rolling Element Bearings ◽  
Fluid Film Bearings ◽  
Thermal Growth ◽  
Morton Effect ◽  
Rolling Element ◽  
Factory Testing

Morton Effect is a known rotordynamic phenomenon associated with fluid film bearings, where viscous heating creates a uni-directional temperature rise in the bearing journal, leading to thermal growth and subsequent bow of the rotor. This results in an unbalance distribution that exacerbates the original unbalance, increasing the heating and bow, resulting in an unstable, or self-amplifying, response. Heretofore, this phenomenon has only been reported in fluid film bearings, as it is traditionally associated with the viscous heating from shearing of the oil. There is also similar behavior associated with phenomenon named the Newkirk Effect where the same mechanics of heating, thermal growth and bowing of a shaft occurs, but the source of heating is a labyrinth rub. This paper describes an incident where such a series of interactions was experienced with a rolling-element bearing (REB). Instead of being driven by viscous shearing of the oil through the minimum film clearance, the uni-directional heating of the rotor results from unbalance and the sliding or dynamic friction of the balls on the inner race or rub of a near-by seal. Rotordynamic analysis was used to derive a correlation between measured vibration levels and temperature rise resulting in predictable bowing of the shaft in a 45,000 RPM fixed speed 250 kW microturbine having an overhung rotor supported by two rolling element bearings. Vibration response was measured with proximity probes along the rotor and temperature predictions were verified against physical evidence in the bearing races. The information gained in this effort was used to establish assembly tolerance and vibration acceptance criteria for factory testing of the turbine. This behavior has internally been described as “REB Morton Effect.” The paper describes the vibration investigation; bearing evaluation; rotordynamic modeling, analysis and verification; design and assembly corrections, and subsequent testing.

Social Cognition in Gilles de la Tourette Syndrome

2019 ◽  
Vol 30 (4) ◽  
pp. 243-249
Author(s):  
Ronja Weiblen ◽  
Melanie Jonas ◽  
Sören Krach ◽  
Ulrike M. Krämer
Keyword(s):  
Tourette Syndrome ◽  
Social Cognitive ◽  
Mirror Neuron System ◽  
Mirror Neuron ◽  
Theoretical Work ◽  
Neural Processes ◽  
The Social ◽  
Decision Making System ◽  
Social Decision Making ◽  
Work Done

Abstract. Research on the neural mechanisms underlying Gilles de la Tourette syndrome (GTS) has mostly concentrated on abnormalities in basal ganglia circuits. Recent alternative accounts, however, focused more on social and affective aspects. Individuals with GTS show peculiarities in their social and affective domain, including echophenomena, coprolalia, and nonobscene socially inappropriate behavior. This article reviews the experimental and theoretical work done on the social symptoms of GTS. We discuss the role of different social cognitive and affective functions and associated brain networks, namely, the social-decision-making system, theory-of-mind functions, and the so-called “mirror-neuron” system. Although GTS affects social interactions in many ways, and although the syndrome includes aberrant social behavior, the underlying cognitive, affective, and neural processes remain to be investigated.

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