Search Results

This paper discusses the change in vehicle parameters when moving from a conventional internal combustion engine (ICE) to an electric motor. In particular, the paper discusses the impact on the wheel end bearings, which must handle higher GAWRs (gross axle weight ratings) at lower center of gravity heights on electric vehicles. These changes require bearings to handle higher loads. Typically, larger loads increase the bearing size and with it, the mounting interface dimensions for auxiliary components. In this paper, The Timken Company demonstrates an alternative bearing design that can handle higher electric vehicle GAWRs but allows for continuity in the surrounding brake corner components - potentially saving OEMs significant design costs and delays. This solution focuses on the mid- and large-size SUV market where bearing capacity could be a limiting factor for electric vehicle variants - driving significant wheel end brake corner design changes to accommodate the larger bearings.

The 100-year saga of The Timken Company is a testament to the enduring power of innovation, grit and periodic self-renewal. It is the story of a quest to solve one of industry's oldest, most limiting and expensive challenges: friction. Today's Timken combines materials science with bearing technology to produce products that range from a half ounce to nine tons and help power and control applications that span disk drives, drilling rigs, dental drills and rolling mills. Today's automotive bearing is less than half the size and 90 percent lighter than its ancestor - and carries twice the load.

The additive chemistry of some gear lubricants can have a major impact on the surface durability of rolling element bearings (1). Lubricant formulation has been slanted heavily toward protecting gear concentrated contacts from galling and wear. As such, much of the performance differentiation of lubricants has been dependent on highly accelerated, standardized laboratory tests related to gears. Methods have been proposed to evaluate and quantify a lubricant's performance characteristics as they relate to rolling element bearings (2). Results from several lubricant performance evaluations are presented. The implications of these findings suggest that the detrimental performance effects on rolling element bearings need further fundamental study by the lubricant industry.

Repair and remanufacture has become an accepted method to extend bearing useful life in many applications, including positions within off-highway construction and mining vehicles. However, it has not been an easy task for equipment owners to become confident in the use of repaired bearings, nor has it been an easy task for engineers to select the positions best suited for repair, as robust analytical methods to predict performance are not available. This has lead to many field test campaigns of repaired bearings on different bearing positions until the equipment owners gain enough confidence to make it part of their normal operating procedures. This paper aims to reduce the test and validation cycle that occurs with the use of repaired and remanufactured bearings by developing analytical methods to predict bearing performance. Life prediction algorithms are presented covering the different levels of repair available.

This paper describes an advanced vehicle dynamics and traction control system, using magnetic-powder clutch technology combined with planetary gear sets.

This study summarizes the development, characterization, and application of nanocomposite tribological coatings on rolling element bearings. Nanocomposite coatings consisting of nanocrystalline metal carbides embedded in amorphous hydrocarbon or carbon matrices (MC/aC:H or MC/aC) have been used to increase the fatigue life under boundary layer lubrication, provide debris tolerance, eliminate false brinelling, increase the operational speed, decrease the friction, and provide oil-out protection to rolling element bearings. MC/aC:H coatings are applied by magnetron sputtering at substrate temperature less than 180 °C, have small friction coefficients, high fracture strength, and can have hardness and modulus values twice and half that of carburized steel, respectively.

Various methods for evaluating the effectiveness of debris resistant bearings have been proposed for development. Once evaluation methods are well established to select bearings, the user is faced with assessing severity and detrimental effects of a specific application's lubricant contamination on bearing performance. Many analysis tools have been suggested for determining this impact, including particle analysis for size distribution, type of material and contamination level. A novel approach for determining severity of damage has been investigated which attempts to integrate these typical tools with actual damage to functional surfaces. It seeks to provide a practical approach and is appropriately labeled Debris Signature Analysis. Results of actual assessments will be discussed and the assessment method described.

Economical steels with improved fatigue life performance continue to be sought for more demanding applications such as in the automotive and aerospace industries. Researchers at The Timken Company, pursuing improved fatigue performance in tapered roller bearings, have found that life is limited by large inclusion stringers that still exist in today's highly publicized steels. Stringers, by definition, are clusters of individual oxide particles observable in wrought steel. An ultrasonic method has been used to quantify the frequency of these stringers in steel in bearing components. The total length of these stringers has been correlated with bearing fatigue life. The use of this ultrasonic tool has expedited the development of the newly introduced Parapretnium™ steel. This air-melted steel has a stringer content less than nearly all of the other worldwide bearing steels evaluated and, in fact, its stringer content is approaching those low levels found only in vacuum-remelted steels.

Many lubrication environments in various equipment applications are inherently contaminated with debris and require mechanical components that are, as much as possible, resistant to the potential detrimental effects of debris particles. Many design engineers and lubricant specialists often overlook potential relationships between the various component failure modes, lubricant debris contamination levels, and engineering solutions that are created to overcome them. In addition, design engineers are in need of an analysis tool that can combine the various amounts of cumulative bearing damage occurring over time. As an example, bearing functional surfaces in many cases are progressively damaged over the life of the equipment. A new surface analysis tool is available which allows surface damage analysis to be completed at various stages of equipment life. This new surface analysis tool is appropriately called Debris Signature Analysis(sm).