摘要:

High-vacuum naphthalene evaporation loss experiments were conducted with a specially designed annular effusion cell to examine the validity of the most frequently used theoretical models of molecular flow, specifically applied to a high molecular weight organic compound. Literature data are similarly correlated to (a) show the respective accuracy of the various formulae and (b) discuss the most prevalent effusion experimental errors often causing orders of magnitude differences between theoretical predictions and experimental results. A simplified molecular flow effusion model is proposed, modified to account for the evaporation rate and rate of vapor pressure change of polymeric lubricating oils. The results and conclusions are useful for accurate predictions of long-term lubricant loss through annular-design labyrinth seals of wet-lubricated aerospace mechanisms and vacuum chamber components.Presented as an American Society of Lubrication Engineers paper at the ASLE/ASME Lubrication Conference held in Atlanta, Georgia, October 16–18, 1973

ISSN:0569-8197    

DOI:10.1080/05698197408981462

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

Measurements of friction and wear during sliding of specimens of Nimonic 75, C263, Nimonic 108 and Incoloy 901 on like specimens in air at temperatures from 20 to 800 C are presented. Under the sliding conditions used, all the alloys show a transition temperature, above which low wear and a low coefficient of friction during sliding are observed after a time and below which these parameters remain relatively high throughout. These temperatures are about 150 C for N75, about 200 C for C263 and N108 and between 200 and 300 for Incoloy 901. At given temperatures above the transition temperatures, the coefficient of friction-time loci show sharp, generally very reproducible, changes from relatively high to low coefficients of friction. The times at which these occur decrease with increasing temperature for a given alloy. Such changes can be closely correlated to the formation of a stable, adherent, thermally softened, oxide layer or glaze on the load-bearing areas during sliding. Once the glaze is established, very little further wear takes place. These tribological properties of the glaze are associated with its low shear strength and the high strength of the underlying alloy substrate. They depend more on its physical properties than on its precise chemical composition. It is concluded that high strength, relatively rapid transient oxidation rates, and appropriate physical properties of the resulting oxide films are important qualities in alloys employed under sliding conditions in air at elevated temperatures.Presented as an American Society of Lubrication Engineers paper at the ASLE/ASME Lubrication Conference held in Atlanta, Georgia, October 16–18, 1973

ISSN:0569-8197    

DOI:10.1080/05698197408981463

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

The load-carrying properties of a range of dialkyl phosphites have been examined under antiwear (AW) and antiscuff conditions using the four-ball machine. Adsorption/reaction of these compounds with iron surfaces has also been carried out. The results showed that both the load-carrying and adsorption/reaction properties of these dialkyl phosphites are markedly affected by the chain length and structure of the alkyl group. A mechanism of action of dialkyl phosphites is proposed which not only provides an explanation for both sets of observations but also highlights the difference in load-carrying action of dialkyl phosphites compared to the corresponding phosphates.Presented as an American Society of Lubrication Engineers paper at the ASLE/ASME Lubrication Conference held in Atlanta, Georgia, October 16–18, 1973

ISSN:0569-8197    

DOI:10.1080/05698197408981464

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

The paper describes the disk machine designed and constructed for the investigation of the traction in elastohydrodynamic line contacts for two synthesized hydrocarbon fluids. The results of this experimental study are presented and compared with the theoretical predictions of traction according to the thermal and non-Newtonian theory recently presented by the authors (1).Presented as on American Society of Lubrication Engineers paper at the ASLE/ASME Lubrication Conference held in Atlanta, Georgia, October 16–18, 1973

ISSN:0569-8197    

DOI:10.1080/05698197408981465

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

ASLE TRANSACTIONS welcomes the comments and suggestions of readers with regard to papers published in its pages or concerning topics of interest to those engaged in any phase of lubrication engineering. Letters received cannot be acknowledged, but those felt to be of interest to other readers will be published. The Society will not be responsible for the statements or opinions expressed.

ISSN:0569-8197    

DOI:10.1080/05698197408981466

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

A series of very simple radioactive chemical tests has been carried out to measure reaction of dibenzyl disulfide on steel. By comparing the results with friction experiments under the same conditions, some of the requirements of extreme pressure lubrication have been determined. Current views on the mechanism of reactions of dibenzyl disulfide have been confirmed and it has been demonstrated that only a thin EP film is needed to give boundary lubrication. In particular, an important additive interference effect has been noted between extreme pressure activity and high temperature detergents.Presented as an American Society of Lubrication Engineers paper at the ASLE/ASME Lubrication Conference held in Atlanta, Georgia, October 16–18, 1973

ISSN:0569-8197    

DOI:10.1080/05698197408981467

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

The behavior of mineral oils under high hydrostatic pressures is studied. It is found that a test oil converts from a liquid to a solid faster than within 9 μs when the time mean value of the pressure is 1,200 N/mm2(— 12,000 atmospheres). As the solidification velocity for liquids increases approximately proportional to the pressure rise above the static solidification pressure, this solidification time shows that rolling element bearings under normal working conditions have solidified oil in the high pressure part of the contact.

ISSN:0569-8197    

DOI:10.1080/05698197408981468

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

The great variety of topics covered by the term tribology needs some guiding principles. These are provided by general systems theory (GST), more in particular a scale of reference proposed by Boulding.

ISSN:0569-8197    

DOI:10.1080/05698197408981469

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

Tribology is an interdisciplinary subject which is connected to parts of mechanical engineering, materials science, physics, chemistry, and other branches of science and technology. Therefore, in research, design, development, and application of tribological objects interdisciplinary superior principles are needed. Such principles may be found using the methods of general systems theory and engineering systems analysis. A general approach on the application of systems thinking to tribology is presented in the preceding article by G. Salomon.

ISSN:0569-8197    

DOI:10.1080/05698197408981470

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor