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Randy Stott, publisher of Power Transmission Engineering and Gear Technology magazines, recently sat down with Norm Parker, technical fellow and technical manager for Torque Transfer Systems at Stellantis, to discuss bearing technology during the Motion + Power Technology Expo in Detroit.
This report derives the equation for relative elastohydrodynamic lubrication (EHL) film thickness. Mineral (MIN), polyalphaolefin (PAO), and polyalkylene glycol (PAG) lubricants with viscosity grades of ISO 320, 150, and 32 are analyzed.
More energy efficiency, higher performance and better controllability are the main reasons why more electric drive systems are being operated with frequency converters. However, these devices can cause high-frequency, asymmetrical interference currents, which, as a current passage through the output and fan-side bearings, can cause damage and premature failure.
Current-compensated CoolBlue toroidal cores made of Magnetec’s nanocrystalline material Nanoperm have proven to be effective protection against such conducted interference and its consequences. In addition, the Nanoperm Line Absorbers NaLA can also be used to significantly suppress symmetrical interference currents.
Rolling bearing calculations are usually based on the assumption of ideal nominal geometries. However, actual components and assemblies are always subject to statically distributed geometric deviations resulting from the manufacturing and assembly processes. This leads to changes in the internal geometric conditions which have an effect on bearing characteristics such as the service life. The FVA-Workbench makes it possible for users to consider these geometric deviations in bearing calculations for more reliable results.
This review of Ref. 1 summarizes the conclusions of test data and numerical simulations showing that Stribeck curves for counterformal contact are different from Stribeck curves for conformal contact.
Technical sales personnel use intelligent features to select suitable motor-gearbox combinations and run calculations based on customer-specific operating data. This provides obvious added value for the customer. Service lives, safeties, and expected loads can all be determined in a short time. Maintenance of the underlying database and the use of simulation tools make it possible to quickly and easily perform technical calculations without having to rely on a central calculation department. In less than a minute, the customer is provided with a data sheet which includes reliable statements about the gearbox based on these technical calculations.
The earliest example of a gear train dates to at least 2,000 B.C. when Chinese engineers built a chariot that used a complex planetary mechanism made of wooden gears to let a dragon head continuously point south when driven around (Ref. 1). In Greece, a surprisingly advanced Antikythera gearbox mechanism, incorporating at least 37 precisely crafted bronze gears, was built years later, between 205–60 B.C. (Ref. 2).