摘要:

Several material combinations were evaluated as gas-lubricated bearings in a hydrodynamic journal bearing test stand. The objective was to compare their performance under start-stop conditions at various stress levels in a helium environment. Some of these tests were run at 296 K, and others were run at 77 K.

ISSN:0569-8197    

DOI:10.1080/05698198508981638

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

Commercial zinc di(nonylphenyl)dithiophosphate (ZDTP) samples have been investigated. Four kinds of zinc salts were identified and quantified; namely, the neutral zinc salt, the basic zinc salt, the basic zinc double salt, and another type of molecule identified as the chelate. The zinc salts and oils were separated and quantified using gel permeation chromatography. Chemical shifts of zinc salts with two, one, and zero sulfur atoms on the phosphorus atom were identified by31P NMR spectrometry.

ISSN:0569-8197    

DOI:10.1080/05698198508981639

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

The use of aqueous lubricants is well established in applications where their fire-resistant properties are of prime importance. A major disadvantage of the use of such fluids, however, is their relatively poor performance in high-stress rolling-contact bearings where components suffer fatigue cracking and pitting at an earlier stage than with mineral oils.

ISSN:0569-8197    

DOI:10.1080/05698198508981640

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

In the present work, investigations by high-frequency resonance technique for diagnosis of defect frequencies of rolling-element bearings are reported. Raw vibration signature of the bearings at different speeds of operation has been demodulated. Envelope detected spectrum is analyzed to evaluate various defect frequencies and their energy levels. Experimentally evaluated frequencies are compared with theoretically determined defect frequencies. These frequency values and their energy levels are used to monitor intrinsic condition of bearings as well as to establish severity of existing/developed defects in the bearings. Relative comparison of bearings of the same type are made at various operating speeds under identical conditions of operation on the basis of identified defect frequencies and severity of defects.

ISSN:0569-8197    

DOI:10.1080/05698198508981641

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

The dynamic behavior of a noncontacting coned-face seal is analyzed. Stiffness and damping properties of the fluid film and flexible support including elastomeric secondary seal are fully accounted for. Stability threshold and steady-state response in the presence of rotor axial runout and assembly misalignment are investigated. An expression is provided for the critical speed above which the seal becomes dynamically unstable. For stable operation, the relative misalignment between the mating faces is given as a function of rotor runout, assembly misalignment, design parameters, and operation conditions. An expression is provided for the critical rotor runout above which the seal will fail due to face contact. Although the analysis is based on small perturbation assumption, it is shown to be valid in many practical cases.Presented as an American Society of Lubrication Engineers paper at the ASLE/ASME Lubrication Conference in San Diego, California, October 22–24, 1984

ISSN:0569-8197    

DOI:10.1080/05698198508981642

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

To develop a bearing which is used in clean circumstances, such as in vacuum and in a clean room, an experimental thrust bearing test device was constructed. The ferromagnetic fluids selected are colloidal suspensions of ultrafine magnetite particles in a low-vapor-pressure diester and alkylnaphthalene base fluids. The friction and wear tests with ferromagnetic lubrication were carried out with stationary cylindrical specimens constructed of permanent magnets in contact with the flat end of opposing rotating nonmagnetic cylindrical specimens.

ISSN:0569-8197    

DOI:10.1080/05698198508981643

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

A test rig has been designed to investigate of some of the kinetic aspects of EP lubrication. Results for sulfurization under very short reaction times by EP additives have been obtained. From these data, some information necessary for the development of a fundamental model to predict scoring in high-speed mechanisms lubricated by sulfur-containing EP oils has been found.Presented as an American Society of Lubrication Engineers paper at the ASLE/ASME Lubrication Conference in San Diego, California, October 22–24, 1984

ISSN:0569-8197    

DOI:10.1080/05698198508981644

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

Four-ball wear studies show that the antiwear (low load) performance of zinc dialkyldithiophosphates (ZDPs) can be duplicated by combining a dialkyl acid phosphate and a soluble zinc compound. Antiwear performance of acid phosphates was independent of chain length for C8to C18but affected by chain branching and ring substitution. Zinc compound effectiveness depended on the strength of the parent acid compared to that of the acid phosphate, and its concentration in the blend (an atomic ratio of 2P:1Zn being optimum). Zinc was the most desirable metal naphthenate tested. Base oil viscosity had little effect on additive effectiveness. Added possible inorganic ZDP reaction products exhibited no antiwear activity. At higher loads in the EP regime, ZDPs lose their antiwear effectiveness, whereas both acid phosphates and sulfur compounds can reduce wear.Presented as an American Society of Lubrication Engineers paper at the ASME/ASLE Lubrication Conference in San Diego, California October 22–24, 1984

ISSN:0569-8197    

DOI:10.1080/05698198508981645

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

The Use of smaller crankshaft bearings is known to reduce the frictional loss for automobiles, resulting in improved fuel economy. However, the bearing life deteriorates when bearing size is reduced, unless engine output is also reduced.

ISSN:0569-8197    

DOI:10.1080/05698198508981646

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

The effects of oil viscosity, base oil temperature, and surface-active agents naturally present in mineral oils on the lubricating effectiveness of MoS2dispersions under boundary lubrication conditions are investigated. Friction and wear data are obtained from tests conducted under a wide range of oil viscosities and operating temperatures. The dispersion temperature at which the friction dropped below that obtained with the base oils, depended upon the base oil viscosity and the concentration of surface-active agents present in the oil. White oils showed reductions in friction before mineral oils of like viscosity, and lower viscosity oils showed reductions in friction before heavier viscosity oils. The results show that for a given base oil, wear increases as temperature increases, while the wear obtained from a MoS2dispersion made from the base oil remains approximately constant as temperature is increased.Presented as an American Society of Lubrication Engineers paper at the ASLE/ASME Lubrication Conference in San Diego, California, October 22–24, 1984

ISSN:0569-8197    

DOI:10.1080/05698198508981647

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor