摘要:

Despite the widespread use of zinc organodithiophosphates (ZDP's) as antiwear additives, how the ZDP's perform their antiwear function is still vague. Thermal decomposition of ZDP's and the formation of a protective antiwear coating by the decomposition products is one popular theory; but the correlation between thermal decomposition temperature and antiwear performance leaves something to be desired. To determine if other factors influence ZDP behavior, bench decomposition studies were conducted on three commercial ZDP's in which the effects of oxygen, water, other additives in the blend, and the base oil were investigated. For these studies, the bulk oil changes were followed by infrared spectroscopy, volatiles formation by pressure measurements, solids formation by centrifugation and subsequent elemental analysis and surface coating formation on steel balls by x-ray fluorescence spectroscopy. It was found that the decomposition of ZDP's is affected by oxygen availability, water, other additives in the blend, and the base oil. Thus, simple thermal decomposition is not an adequate explanation; and a better theory is needed to explain the antiwear behavior of ZDP's.Presented at “Symposium on Colloid and Surface Chemical Aspects of Lubrication and Lubricants,” (Society of Chemical Industry) University of Bristol, England, September, 1973.

ISSN:0569-8197    

DOI:10.1080/05698197508982749

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

This paper presents a model for mixed lubrication. The surface asperities are represented by short plasto-elastic cylinders with spherical tops. The heights of these cylinders are assumed to have a Gaussian distribution. By combining the solution of the Reynolds equation and the solution from boundary lubrication theory or the microelastohydrodynamic lubrication theory, the load and friction of the lubricated contact can be calculated. Three calculated examples which showed the essential characters and interesting results of mixed lubrication were given. The correlation with others' experimental results was reasonably good.

ISSN:0569-8197    

DOI:10.1080/05698197508982750

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

Two sets of Falex test specimens were examined to determine the compressive stresses in the contact zones at the time of lubricant failure. Two wear scar variations were found: (1) between sides of the same vee block, and (2) between vee blocks from the same test. To explain these anomalies, a force analysis of the Falex configuration was made. The force analysis of a vee block revealed that the two faces have the same normal loads only when there is no motion. Details and force curves are presented. The force analysis of the lever system revealed that only if the two halves of the lever system were identical (with manufacturing tolerances identical) would the loading on the two vee blocks in a single test be the same. Conclusions relative to the analysis and final compressive stress results are made.Presented at the 29th Annual Meeting in Cleveland, Ohio, April 28–May 2, 1974

ISSN:0569-8197    

DOI:10.1080/05698197508982751

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

An elastodynamic stress and deformation analysis for the hollow ball is given. A computer program for the stress analysis, though not part of the paper, is available upon request.Presented as an American Society of Lubrication Engineers paper at the ASLE/ASME Lubrication Conference held in Montreal, Canada, October 8–10, 1974

ISSN:0569-8197    

DOI:10.1080/05698197508982752

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

The paper describes a method of successive approximations for calculating lubricant film pressures in plane bearings under the combined action of hydrodynamic and hydrostatic lubrication. Successive iterations are obtained through redefinition of the boundary pressures. The accuracy and convergence of the method are discussed.

ISSN:0569-8197    

DOI:10.1080/05698197508982753

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

The oscillating quartz crystal viscometer has been used to investigate possible viscoelastic behavior in synthetic lubricating fluids and to obtain viscosity-pressure-temperature data for these fluids at temperatures to 300 F and pressures to 40,000 psig. The effect of pressure and temperature on the density of the test fluids was measured concurrently with the viscosity measurements.

ISSN:0569-8197    

DOI:10.1080/05698197508982754

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

In testing high strength, elastic materials by the four-point bending method, large deflections can occur. Under these conditions the relationship between load and deflection becomes nonlinear and analyses of results based on simple beam theory may lead to serious errors. Furthermore, friction between the test piece and supports can have an important effect on the results. A numerical analysis is presented which takes into consideration both the nonlinear and frictional effects. The analysis shows that frictional forces can become significant at large deflections and cause an increase in the measured strength. Experimental evidence is given to support these analytical results.Presented at the 29th Annual Meeting in Cleveland, Ohio, April 28–May 2, 1974

ISSN:0569-8197    

DOI:10.1080/05698197508982755

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

If a lip seal could use a liquid lip, the resulting perfect conformity to the rotating and stationary surfaces would negate the effects of surface finish and mechanical run-out. Magnetic fluids, called ferrofluids, make this type of seal possible and practical. This paper discusses magnetic fluids: what are they, what are their intrinsic properties, and how can they be controlled and positioned to create zero-leakage, nonwearing ferrofluidic seals. Design parameters of ferrofluidic seals including radial gap, differential pressure, rotary speed and torque are developed. Specific examples of hard-vacuum, exclusion and rotating-machinery applications illustrate the versatility of magnetic-liquid seals, which have been used primarily for gas service. Other potential seal applications include packings, face seals, and conventional lip seals which can benefit from use of newly developed magnetic-fluid lubricants.Presented at the 29th Annual Meeting in Cleveland, Ohio, April 28–May 2, 1974

ISSN:0569-8197    

DOI:10.1080/05698197508982756

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

A statistical expression, showing as a function of the film parameter (film thickness/surface roughness or h/σ) the fractional reduction in fatigue life at “full film” conditions due to the competition between asperity induced fatigue and fatigue due to indigenous surface defects and subsurface inclusions, is presented.

ISSN:0569-8197    

DOI:10.1080/05698197508982757

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor