摘要:

An experimental study on the performance of hybrid bearings in a lubrication environment where the oil contains metallic particles, such as found in industrial gearboxes and transmissions is conducted. Improvements in the wear resistance performance of hybrid bearings are reported and compared with the performance achieved by conventional steel bearings. The performance merits of hybrid bearings under commonly used grease lubrication conditions operating at high speed and temperature is also described. The mechanisms and advantages gained by adopting hybrid rolling-element bearings as a means of extending the service life of mechanical systems or machines operating in highly demanding environmental conditions are discussed.Presented at the 52nd Annual Meeting in Kansas City, Missouri May 18–22, 1997

ISSN:1040-2004    

DOI:10.1080/10402009708983711

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

This paper studies mechanisms of surface dents in enhancing the fatigue life of rolling bearings previously reported in Akamatsu et al. (1). First, transient micro-EHL analyses of heavily loaded contacts between rough surfaces with multiple dents are conducted under near rolling conditions. Contacts with various dent dimensions, dent arrangements under different loading and kinematic conditions are investigated. Results show that surface dents generate no favorable micro-EHL effects to enhance the contact fatigue life. Subsequent analyses, in conjunction with other published studies, suggest that the fatigue life enhancement likely comes from the reduced local traction at asperity contacts through the “oil pots” effects of the dents. The effects of the surface dents on contact fatigue life may depend on the lubrication regime in which the contact is operating being favorable in poor lubrication conditions but adverse in well-lubricated contacts. Since rolling bearings are usually designed to operate in a healthy regime of lubrication, fatigue life enhancement by artificially introducing dents on bearing surfaces may not extend to field applications.Presented at the 51st Annual Meeting in Cincinnati, Ohio May 19–23, 1996

ISSN:1040-2004    

DOI:10.1080/10402009708983712

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

An experimental study of pneumatic seal extrusion is presented. Direct visual observations are made. An empirical formula for calculating extrusion based on the geometric characteristics of the sealing system is presented.

ISSN:1040-2004    

DOI:10.1080/10402009708983713

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

The wear characteristics of larger than 120 mm-diameter grinding balls used in large semiautogenous (SAG) mills is studied in the present paper. SEM observation on the worn ball surface reveals a severe microcutting process. Abrasion grooves can be found on the overall surface. Moreover, persistent microcracks are found on the surface. The observation on the cross section indicates extended white layers and white bands exist in the subsurface of worn balls. The white layer is not homogenous on the surface. The largest white layer is about 20 μm thick and 1.3 mm long. The wear resistance of the white layer is tested with a simulated high stress impact wear tester. It is found that the white layer is associated with delamination wear, which significantly increases the wear rate. The delamination wear mechanism is explained from the intensely deformed microstructure and microcracks inside the white layer. Based on the experimental results, a wear formula consisting of both microcutting wear and delamination wear is submitted. This formula means that high wear resistance is only achieved when the hardness and fracture toughness of grinding balls are increased simultaneously.Presented at the 52nd Annual Meeting in Kansas City, Missouri May 18–22, 1997

ISSN:1040-2004    

DOI:10.1080/10402009708983714

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor