LEEVENSPARK

The Birfield joint, manufactured by Hardy Spicer Limited , is based on the Rzeppa principle (Fig. 26.17). In this construction the joint's performance has been improved further by incor­porating converging ball tracks, which do not rely on a controlled ball cage to maintain the intermediate ball members on the median plane (Fig. 26.17B). This Joint uses an inner (ball) input member driving an outer (cup) member. Torque is transmitted from the input to the output member again by six intermediate ball members, which fit into curved rack grooves formed in both the cup and spherical members. Articulation of the joint takes place due to rolling of the balls in between the inner and outer pairs of curved grooves. Constant velocity conditions are achieved by an intermediate member, formed by a ring of six balls placed in the median plane (Fig. 26.17B) of the shape of the curved ball tracks generated in both the input and output joint members.  Fig. 26.17. Birfield. Rzeppa type consta

A Ford engineer, Alfred Hans Rzeppa (pronounced sheppa) invented one of the first practical constant velocity joints in 1926. This joint was able to transmit torque over a wide range of angles. An improved version of the joint was patented by Rzeppa in 1935.  This version uses six balls as intermediate members, which are kept at all times in a plane bisecting the angle between the input and output shafts (Fig. 26.16). A controlled guide ball cage is incorporated, which maintains the balls in the bisecting plane (or the median plane) by means of a pivoting control strut, which swivels the cage at the correct angle.  This control strut is located in the centre of the enclosed end of the outer cup member. Both ball ends of the strut are positioned in a recess and socket formed in the adjacent ends of the driving and driven members of the joint respectively. A large spherical waist approximately midway along the strut aligns with a hole made in the centre of the cage. Any angular inclinati

Universal Joints Universal joints are capable of transmitting torque and rotational motion from one shaft to another when their axes are inclined to each other by some angle, which may constantly vary under working conditions.  Universal joints are incorporated in the of vehicle's transmission system to perform three basic applications :  (a) Propeller shaft end joints between longitudinally front mounted gearbox and rear final drive axle.  (b) Rear axle drive shaft end joints between the sprung final drive and the unsprung rear wheel stub axle.  (c) Front axle drive shaft end joints between the sprung front mounted final drive and the unsprung front wheel steered stub axle. Universal joints have movement only in the vertical plane when they are used for lon­gitudinally mounted propeller shafts and transverse rear mounted drive shafts. When these joints have been used for front outer drive shaft they have to move in both the vertical and horizontal plane to accommodate both vertica