Advanced Shaft Coupling Design

This project addresses the analytical modelling of a particular class of mechanical shaft couplings. Such couplings are used to connect rotating shafts which intersect at an angle. Those prevalent in practice include the universal joint and the constant velocity joint. The latter class includes the Rzeppa coupling which is the subject of this study. These couplings are used in a variety of applications, most notably in the wheel drives of front wheel drive automobiles, where transmission of constant angular rate is desired. Presently, Rzeppa couplings are designed empirically. The general procedure is to construct a number of prototypes embodying the wisdom of prior experience and then proof test to determine which model should be put into production. If none is adequate, then repeating the procedure is required. In the today's competitive world with its demands for higher speeds, increased loads, and improved reliability, this method is excessively expensive and time consuming. The purpose of this study is to provide analytical procedures for the design of Rzeppa couplings. Dual number element coordinate transformation matrix methods will be applied to analyze its kinematic and static behavior. Specific topics addressed herein include synthesis of pilot lever proportions, cyclic velocity fluctuations through pilot lever manipulation, Rzeppa coupling groove geometry, load sharing among coupling balls, general analysis methodology, and experimental investigations. This investigation has the added feature that it will further generalize the analysis procedures for general spatial mechanisms.