Mechanical Efficiency of Differential Gearing
Mechanical Efficiency 01£ Differential Gearing D. Yu N. Beachley University of Wisconsin Madison, Wisc.onsin lltustration cou~te5yof Bred Foote Gear Works. Inc. Cicero, It Introduction General Considerations and Definitions Mechanical efficiency is an important index of gearing, It is necessary and important. to provide some precise and especially for epicyclic gearing. Because of its compact size, accurate definitions, otherwise confusion and mistakes are light weight, the capability of a high speed ratio, and the liable to occur. ability to provide differential action, epicyclic gearing is very fundamental Diff:erenHal. A fundamental differential has versatile, and its use is increasing. However, attention should three basic members that can input or output power, in- be paid to effieiency not only to save energy, but sometimes cluding the carrier (Fig..2). Without a carrier, there is no dif- also to make the transmission run smoothly or to avoid a ferentia], so the carrier is an important member and is sym- sel:f-locking condition. For example, a Continuously Variable bolizedas H. Strictly speaking, a fundamental differential has Transmission (CVT) is attractive for motor vehicles (and two degrees of freedom, i.e., two constraints must be given, especially for flywheel or other energy storage hybrid otherwise the relationships among the three members are in- vehicles), but most types of CVT have poor efficiency, and dependent. For example, if two or the three members are the energy loss of a vehicular CVT can be comparable to the given as inputs, then the other can be determined as the out- road load energy. (1) The split-path or bifurcated power put.
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