摘要:

Commercial aqueous polyglycol hydraulic fluids are found to give very low elastohydrodynamic film thicknesses. By studying mixtures of polyglycol, monoglycol, and water, it is shown that this is became the pressure-viscosity coefficients of polyglycol and monoglycol fall very sharply when they are mixed together or when water is added. Over the polyglycol, monoglycol, water mixture range, pressure-viscosity coefficient appears to be inversely related to free volume.Presented as an American Society of Lubrication Engineers paper at the ASLE/ASME Lubrication Conference in Hartford, Connecticut, October 18–20, 1983

ISSN:0569-8197    

DOI:10.1080/05698198408981582

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Light optical and scanning electron microscope studies were conducted to characterize the erosion resistances of polymethyl methacrylate (PMMA), polycarbonate (PC), polytetrafluoroethylene (PTFE), and ultrahigh-molecular-weight polyethylene (UHMWPE). Erosion was caused by a jet of spherical microglass beads at normal impact. During the initial stages of damage, the surfaces of these materials were studied using a profilometer. Material buildup above the original surface was observed on PC and PMMA. As erosion progressed, this buildup disappeared as the pit became deeper. Little or no buildup was observed on PTFE and on UHMWPE. UHMWPE and PTFE are the most resistant materials and PMMA the least. Favorable properties for high erosion resistance seem to be high values of ultimate elongation, and strain energy and a low value of the modulus of elasticity. Erosion rate versus time curves of PC and PTFE exhibit incubation, acceleration, and steady-state periods. A continuously increasing erosion rate period was observed, however, for PMMA instead of a steady-state period. At early stages of damage and at low impact pressures, material removal mechanisms appear to be similar to those for metallic materials. “Flakelike” debris was observed on the surface which is indicative of deformation wear by repeated impact and eventual fatigue, causing material loss. At higher impact pressures, evidence of melting of the surface was noted, which is believed to be the result of heat generated by impact.Presented as an American Society Of Lubrication Engineers paper at the ASLE/ASME Lubrication Conference in Hartford, Connecticut, October 18–20, 1983

ISSN:0569-8197    

DOI:10.1080/05698198408981583

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Many studies have been published on the use of solid fluorinated compounds as lubricants and lubricant additives, but much less has been done with oil-soluble fluorinated additives.

ISSN:0569-8197    

DOI:10.1080/05698198408981584

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

The influence of molecular weight, crystalline structure, and surface energy of high-density polyethylene (HDPE) upon initial friction and transfer behavior was studied on a pin-and-disk tribometer, at low speed (1.6 mm/s) 20°C and 12 percent relative humidity, using:

ISSN:0569-8197    

DOI:10.1080/05698198408981585

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

The effect of a small proportion of a polar additive in paraffinic base oils has been studied. The experimental test device is a disk machine. The traction is measured in different lubrication regimes. First of all, as a reference, it was found that in the real EHD regime (Λ > 2), no friction-reduction effect occurs. In contrast, where a thin-film situation exists (Λ < 2), an important friction modification appears. Evidence is given that this effect is related to the presence of an absorbed layer on metal surfaces. These results are also discussed in terms of structural properties of the solution.Presented as an American Society of Lubrication Engineers paper at the ASLE/ASME Lubrication Conference in Hartford, Connecticut, October 18–20, 1983

ISSN:0569-8197    

DOI:10.1080/05698198408981586

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

The analysis presented herein deals with the evaluation of the pressure, velocity, and temperature profiles in a finite-length plane journal bearing. The geometry of the case under study consists of a spatially tilted shaft. The two-dimensional Reynolds equation accounts for the variation of the clearance gap h with x and z and is used to model the pressure field. The latter is solved for a variety of shaft tilt angles and then used to calculate the two-dimensional flow field. Finally, the flow field is used in the energy equation to solve for the film temperature profile, when the effect of viscous dissipation is taken into account.Presented as an American Society of Lubrication Engineers paper at the ASLE/ASME Lubrication Conference in Hartford, Connecticut, October 16–20, 1983

ISSN:0569-8197    

DOI:10.1080/05698198408981587

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor