rolling element

Articles About rolling element

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1 Bearing Lubrication Under Extreme Conditions, Part II (February 2008)

Rolling element or sleeve bearings often are required to operate under extreme conditions. In these instances, it is more important than ever to follow proper lubrication selection and maintenance procedures to maximize effective life and efficient performance.

2 Wear-Resistant Bearings (August 2012)

More than a decade of intensive research and development has resulted in two new technologies that, when used in combination, expand the performance of rolling element bearings well beyond previous limits.

3 Investigations of Bearing Failures Associated with White Etching Areas (WEAs) in Wind Turbine Gearboxes (March 2014)

A critical problem for wind turbine gearboxes is failure of rolling element bearings where axial cracks form on the inner rings. This article presents field experience from operating wind turbines that compares the performance of through-hardened and carburized materials. It reveals that through-hardened bearings develop WEA/WECs and fail with axial cracks, whereas carburized bearings do not. The field experience further shows that a carburized bearing with a core having low carbon content, high nickel content, greater compressive residual stresses, and a higher amount of retained austenite provides higher fracture resistance and makes carburized bearings more durable than through-hardened bearings in the wind turbine environment.

4 Bearings for High Temperatures (Fall 2007)

When rolling element or sleeve bearings operate under extreme conditions, it’s more important than ever to follow proper lubrication selection and maintenance procedures to maximize eff ective life and effi cient performance.

5 What Lubrication Method Should I Use (April 2016)

in the performance and life of a rolling element bearing. Less than 10 percent of bearings reach their theoretical L10 life, and poor lubrication can be attributed to 80 percent of those that fall short. Ideally, a lubricant forms a film layer between moving components in a bearing, separating moving parts, minimizing friction and preventing wear between balls or rollers, raceways and retainers. Lubricants also protect metal surfaces from corrosion and moisture, dissipate heat and can even prevent the ingress of contaminants.

6 Determination of Load Distributions on Double Helical-Geared Planetary Gearboxes (June 2017)

Standardized calculation methods such as ISO 6336 and DIN 3990 already exist to determine the load distributions on gears inside a planetary gearbox, but by their very universal nature, these methods offer varying results depending on the gearbox design. Double helical gears, in particular, can benefit from more specific, complex algorithms to reach a maximum level of efficiency. Double helical gears interact with the rest of the gearbox differently than helical or spur gears, and thus benefit from different analytical models outside the standardized methods. The present research project describes the algorithm to determine the load distribution of planetary gearboxes with double helical gears.

7 Electromagnetic Know-How (August 2012)

Finite Element Analysis (FEA) software can be used for a variety of mechanical engineering tasks, including injection molding simulation of plastic parts, analysis of aerospace components, impact and crash analysis of automobiles and the electromagnetic analysis of motors, actuators, transformers and sensors.

8 Rolling Bearings in High-Speed Passenger Traffic (June 2012)

Passenger transport today moves significantly faster than ever before, often operating on separate tracks especially designed for high-speed trains. Accordingly, high-speed rolling bearings are very important components in the bogies of trains today. Maximum train speeds currently reach 380 km/h (236 mph) in the latest high-speed applications - 80% higher than in the earlier days of high-speed traffic. This paper presents two application examples of modern, high-speed traffic, together with some typical bearing arrangements and housings. It provides insight regarding measures taken in the bearing industry to meet the requirements of contemporary, high-speed traffic, and it cites important standards and regulations applicable for - but not restricted to - European applications. To be precise, the focus here is on journal bearings; information on traction motor bearings, transmission bearings and housings is included, but described in less detail.

9 Rolling Bearing Steels - A Technical and Historical Perspective - Part 1 (February 2013)

This paper summarizes the chemical, metallurgical and physical aspects of bearing steels and their effect on rolling bearing life and reliability.

10 The Modified Life Rating of Rolling Bearings: A Criterion for Gearbox Design and Reliability Optimization (March 2015)

Engineers typically learn that the bearing L10 life can be estimated using the so called “C/P method” — or the “basic rating life” of the bearing, a method rooted in the 1940s. Major developments have since led to the “modified rating life,” released in ISO 281:2007, which includes the aiso life modification factor. In this paper a succession of equations used for bearing life ratings are reviewed, and current bearing life rating practices are discussed in detail. It is shown that — despite the introduction more than 30 years ago of the adjustment factor of the basic rating life, and the standardization in 2007 of the aiso modification factor — use of these improved calculation methods are not practiced by all engineers. Indeed — many continue referring to the old model as a way of seeking compliance with existing, established practices.

11 A Model for Rolling Bearing Life with Surface and Subsurface Survival - Tribological Effects (September 2016)

Until now the estimation of rolling bearing life has been based on engineering models that consider an equivalent stress, originated beneath the contact surface, that is applied to the stressed volume of the rolling contact. Through the years, fatigue surface–originated failures, resulting from reduced lubrication or contamination, have been incorporated into the estimation of the bearing life by applying a penalty to the overall equivalent stress of the rolling contact. Due to this simplification, the accounting of some specific failure modes originated directly at the surface of the rolling contact can be challenging. In the present article, this issue is addressed by developing a general approach for rolling contact life in which the surfaceoriginated damage is explicitly formulated into the basic fatigue equations of the rolling contact. This is achieved by introducing a function to describe surface-originated failures and coupling it with the traditional, subsurface-originated fatigue risk of the rolling contact. The article presents the fundamental theory of the new model and its general behavior. The ability of the present general method to provide an account for the surface–subsurface competing fatigue mechanisms taking place in rolling bearings is discussed with reference to endurance testing data.

News Items About rolling element

1 Papers Invited for Rolling Element Bearings Symposium (May 11, 2010)
The 2011 ASTM International Symposium on Roller Element Bearings is accepting papers. The symposium is sponsored by the ASTM Internationa...

2 Papers Invited for Rolling Element Bearings Symposium (August 6, 2010)
The 2011 ASTM International Symposium on Roller Element Bearings is accepting papers. The symposium is sponsored by the ASTM Internationa...