摘要:

AbstractSynthesised lubricant base stocks and the performance additives used in hypoid gear lubricants can both be chemically designed to give improved hypoid gear efficiency and, therefore, better vehicle fuel economy than provided by conventional lubricantsIn this paper, the authors review, relative to a widely used SAE 90 grade mineral oil‐based lubricant, the changes in gear efficiency which have been documented using certain classes of synthesised lubricants. These advantages are described in terms of (a) EPA City and Highway Cycle efficiencies, (b) absolute data over a wide temperature range under four selected speed/torque combinations, and (c) absolute changes in inefficiency compared to the mineral oil product.Newtonian and non‐Newtonian fluids have been studied. The bulk oil temperature at which a specific lubricant gives maximum efficiency is dependent on both gear operating conditions and on the chemical composition of the lubric

ISSN:0265-6582    

DOI:10.1002/jsl.3000110102

出版商:John Wiley&Sons, Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractAs an alternative to tapping torque measurement and thread finish evaluation, a reaming test is suggested for the evaluation of the lubricating efficiency of cutting fluids. An investigation was carried out where results from tapping torque measurements were compared with those from measuring torque, feed force, and surface roughness in reaming. Two different tap geometries and two different reamer geometries were used. Technically‐pure aluminium was used as the workpiece material and four laboratory water‐based cutting fluids as well as a commercial cutting oil were investigated.The results show that lubricants have a significant and similar effect with respect to both tapping torque and reaming torque, when tools with straight flutes are used. In reaming, a more comprehensive picture of lubrication can be obtained if torque measurement is accompanied by determination of the surface roughness. In a subsequent investigation, the reaming torque and roughness test was used to evaluate two different water‐based cutting fluids and a neat oil, using austenitic stainless steel as the workpiece mat

ISSN:0265-6582    

DOI:10.1002/jsl.3000110103

出版商:John Wiley&Sons, Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractDry lubricants are often used in space because of their excellent behaviour in a vacuum and their thermal stability. However, mechanisms which are heavily loaded, with a high sliding rate, a long life span, or needing a stable friction coefficient cannot use this kind of product. They can be replaced by wet lubricants specially developed for vacuum applications. Such lubricants have a low vapour pressure in order to minimise outgassing losses and avoid contamination.Since European experience in the field of wet lubrication in space is rather limited, the French Space Agency CNES, with the help of the LMC (Laboratoire de Mécanique des Contacts ‐ Contact Mechanics Laboratory), is currently characterising several wet lubricants for use in space applications.The selected lubricants were tested on a vacuum friction test bench which allows the main contact parameters to be controlled: speed, load, and kinematics. The bench is equipped with vacuum facilities and, since it runs under air, neutral gas, or vacuum, it can be used to study the effects of atmosphere. Variations of physical properties (viscosity) versus temperature (−60°C to 100°) and pressure (from atmospheric pressure to 500 MPa) were studied for all the lubricants tested, and these characteristics take into account in the analysis of the tribological test results.This paper briefly lists the characteristics of a space environment (vacuum, microgravity, etc.) and their consequences for lubrication. It describes the equipment used and the tribological and rheological test results obtained on six wet lubricants (three oils and three greases). It also contains conclusions in terms of recommendations about the use of such lubr

ISSN:0265-6582    

DOI:10.1002/jsl.3000110104

出版商:John Wiley&Sons, Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractWith the widening use of plastics, it has become an urgent task to study their behaviour in friction systems. The present paper reviews the applications of plastics during the past decades and their function in friction systems. The paper analyses the basic differences between metals and plastics in structure and properties, and points out the limitations, or inapplicability, of using metal tribology to solve problems in plastic friction systems when even different kinds of high‐molecular materials have different shapes and applications.The paper also looks at the variety of plastic surfaces, and briefly presents the mechanism, theory, and calculation of the fiction, wear, and lubrication of plastics; theories of plastic wear are summarised. Also presented are the technical functions, simple application techniques, and economic benefits of plastic friction system

ISSN:0265-6582    

DOI:10.1002/jsl.3000110105

出版商:John Wiley&Sons, Ltd    

年代:1994

数据来源: WILEY

ISSN:0265-6582    

DOI:10.1002/jsl.3000110106

出版商:John Wiley&Sons, Ltd    

年代:1994

数据来源: WILEY

ISSN:0265-6582    

DOI:10.1002/jsl.3000110107

出版商:John Wiley&Sons, Ltd    

年代:1994

数据来源: WILEY

ISSN:0265-6582    

DOI:10.1002/jsl.3000110108

出版商:John Wiley&Sons, Ltd    

年代:1994

数据来源: WILEY

ISSN:0265-6582    

DOI:10.1002/jsl.3000110101

出版商:John Wiley&Sons, Ltd    

年代:1994

数据来源: WILEY