摘要:

For a long time, the tooth surface strength of gears has been investigated under various conditions. At first research concerning tooth surface strength focused mainly on gears of lower hardness. Because the practical usage of gears with high hardness has recently increased considerably, a more fundamental research on tooth surface strength of gears with high hardness is required to increase the load carrying capacity of gears. Recently, many basic studies on the tooth surface strength of gears were carried out in order to improve tooth surface strength. But further research on tooth surface strength is still needed. In view of this present state of research, the authors developed a project to carry out preparatory experiments mainly on the following topics: (1) tooth surface strength using various lubricating oils, (2) tooth surface strength under various effective depths of case-hardening of tooth surfaces, (3) tooth surface strength using test gears with shot peening treatment, (4) tooth surface strength under various tooth surface treatments, and (5) tooth surface strength as a function of tooth hardness.

ISSN:1040-2004    

DOI:10.1080/10402009908982193

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

Differential scanning calorimetry (DSC) and oxidation-corrosion tests were employed to evaluate the inhibition of pentaery-thritol ester containing sodium perfluorobutyrate (C3F7COONa) towards oxidation. The results show that C3F7COONa enhances antioxidancy of p,p'dioctyldiphenylamine (DODPA). The changes occurring to DODPA in the oxidation of esters, with and without C3F7COONa, were followed by mass (GC/MS) chromatography (MC). The proposed mechanism of the inhibition involves a synergy between alkali metal salts and arylamines. Although DODPA does not react directly with the alkali salt, the salt still functions within the antioxidation mechanism of DODPA. When DODPA reacts with free radicals to form alkyl and hydroxy substituted benzoquinonemonoimine compounds (with mass to charge ratio M/Z, 422), the alkali metal ion can participate and produce a new intermediate product having high antioxidant activity; this intermediate product serves as the main antioxidant, long after the depletion of DODPA. This process may involve a reaction between alkylphenylamino alkylphenol and the alkali metal ion. The intermediate product is believed to be the salt of alkylphenylamino alkylphenol.

ISSN:1040-2004    

DOI:10.1080/10402009908982194

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

Over the years, many bench tests have been used to guide synthetic organic chemists in their quest for new molecules to prevent valve train wear. Which bench tests to choose has always been an important issue, especially when the goal is to prevent valve train wear in an internal combustion engine, a very complicated system. Essential antiwear additives in modern engine oils are zinc dithiophosphates (ZnDTPs) and, although these materials have been used extensively, the fundamental mechanisms of their chemistries are not that well understood.

ISSN:1040-2004    

DOI:10.1080/10402009908982195

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

A finite-volume-based numerical method with a strongly implicit relaxation procedure is developed to solve the elastohydrodynamically lubricated point contact problem. The multigrid algorithm for the solution of the governing equations and the multilevel multi-integration technique for the elastic deformation equation are also developed within the finite-volume framework. The performance of the developed finite-volume method has been evaluated extensively. The proposed method has a computational complexity of O(n log n) where n is the total number of control volumes. Up to 6.18 GPa maximum Hertzian pressure case has been calculated and demonstrated.Presented at the 53rd Annual Meeting in Detroit, Michigan May 17–21, 1998

ISSN:1040-2004    

DOI:10.1080/10402009908982196

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

The self-lubricating performance of the two types of modified, angular-contact 25-mm-bore ball bearings, i.e., a hybrid ceramic bearing with Si3N4ceramic balls and an all-steel bearing, was evaluated based on wear inspection as well as X-ray photoelectron spectroscopic (XPS) analysis of transfer films. These bearings had been tested in liquid hydrogen (LH2), liquid oxygen (LO2), or liquid nitrogen (LN2) at speeds to 50,000 rpm and thrust loads to 2840 N.

ISSN:1040-2004    

DOI:10.1080/10402009908982197

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

This paper will discuss results of metallurgical and metrological examinations of cylinder liner and piston ring surfaces before and after 150, 1000 and 4000 hours of heavy duty diesel engine testing. Three different composition coatings and three methods of application were investigated, including electroplating, plasma and HVOF spraying. To examine metallurgical parameters such as porosity, microhardness, microstructure and their changes after testing, scanning electron microscopy and energy dispersive X-ray spectroscopy were used. The cylinder liner and piston ring surface profile and roughness parameters include Ra, Rz, Rk, Rvk, Rvk, skewness, oil retention volume, etc. The mechanisms of scuffing origin and final wear were evaluated for different piston ring coatings and methods of application. The paper will show the correlation between metallurgical and metrological parameters and efficiency of the cylinder liner-piston rings tribological system. The data from these examinations formulates required performance for transformation of abnormal and/or severe type of wear to mild processes.Presented as a Society of Tribologists and Lubrication Engineers paper at the World Tribology Congress in London, United Kingdom, September 8–12, 1997

ISSN:1040-2004    

DOI:10.1080/10402009908982198

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

A test facility was developed for the experimental investigation of the large spring-supported thrust bearings used in hydroelectric generators. The test bearing had an outer diameter of 1.168 m, thus making it large enough to simulate most of the features of the thrust bearings in the field, yet small enough to be placed cönveniently in an engineering laboratory. Instrumentation included a distribution of thermocouples and pressure taps along with displacement probes of eddy current type that were located in the rotor to measure oil film thickness. A detailed description of the test facility was provided along with some representative results and a description of some experimental difficulties. A survey of the relevant literature published in the past 40 years suggested that this apparatus was unique in its ability to study relatively large spring-supported thrust bearings in the laboratory.Presented as a Society of Tribologists and Lubrication Engineers paper at the World Tribology Congress in London, United Kingdom, September 8–12, 1997

ISSN:1040-2004    

DOI:10.1080/10402009908982199

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

Bearing life of the rotating race is analyzed numerically in the case of continuous rotation (L10_cont) and in the case of oscillatory application (L10_osc).

ISSN:1040-2004    

DOI:10.1080/10402009908982200

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

The authors suggested a boundary friction model which treats the combined influence of surface roughening (due to inhomogeneous deformation) and surface smoothing (due to asperity flattening) on the real area of contact in the presence of plastic strain. Predictions using the new model for sheet metal forming indicate that the friction coefficient tends to decrease with strain for low pressures (when roughening is of dominant importance) and tends to increase with strain for high pressures (when asperity flattening prevails). This behavior was confirmed experimentally by friction measurements for 6022-T4 aluminum sheet stretched over A2 steel pins of different diameters with a commercial lubricant. Average coefficients of friction predicted by the model were in good agreement with those measured experimentally.Presented at the 53rd Annual Meeting in Detroit, Michigan May 17–21, 1998

ISSN:1040-2004    

DOI:10.1080/10402009908982201

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

For several decades, intensive research of tooth surface strength of gears has been undertaken to achieve better gear design. Because the practical usage of gears with high hardness has recently increased considerably, a more fundamental research on tooth surface strength of gears with high hardness is required to increase the load-carrying capacity of gears. In view of this present state of research, the authors carried out many experiments in depth mainly on the following topics: (1) tooth surface strength using various lubricating oils in various conditions, (2) tooth surface strength under various effective depths of case-hardening of tooth surfaces, (3) tooth surface strength using test gears with shot peening treatment, and (4) tooth surface strength under various tooth surface treatments (through hardening and nitriding), and (5) tooth surface strength as a function of tooth hardness.

ISSN:1040-2004    

DOI:10.1080/10402009908982202

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor