Universal Joints and Driveshafts H.Chr.Seherr-Thoss · F ... - Index of

14 1 Universal Jointed Driveshafts for Transmitting Rotational Movements
The advantages of the Tracta joint are:
– it transmits movement at articulation angles up to about 32°
– it appears simpler than the double Hooke’s joint
– it can be lubricated well because of the large sliding surfaces; the contact faces of
the joint spheres slide on each other
– it is easy to fit into the swivel of a rigid front axle with the joint being located
axially by thrust faces on the bearing bushes.
The disadvantages of the Tracta joint are:
– it gets very hot at high speeds due to the sliding movement
– the centre of the joint and intersection point of the rotational axes of the joint are
hard to adjust
– an elaborate bearing housing is necessary because the joint has no self-centring.
The Tracta joint was fitted in independent suspension, front wheel drive passenger
cars and in the steering knuckles of the front axles of four wheel drive military personnel
cars. It held a dominant position for 40 years before the arrival of the selfcentring
constant velocity ball joint.
1.2.4.2 Various Further Simplifications
Approximate solutions to constant velocity joints were attempted in 1922 by Mechanics
and Julie-Marie-René Retel (French patent 550880), in 1930 by Chenard &
Walcker, and in 1931 by Hanns Jung for the DKW front wheel drive small car. With
Jung’s solution the displacements occurred in the steering yoke between the input
and the shell (Fig. 1.14); the ball pivot formed the mid-point of the king pin axis. This
DKW joint worked like a hinge in one direction and as a double joint in the other. In
later improved versions the travel of the ball pivot was increased through a spherical
joint which was open at both sides. Jung’s hinged joint was fitted in several Auto
Union passenger car models from 1931 to 1963.
In 1949 Marcel Villard designed a five-part joint (Fig. 1.15) which was subsequently
fitted in the Citroën 2 CV small car with front wheel drive. Four parts
(3 – 6), sliding in semicircular recesses allowed articulation and rocked on machined
serrations, the axes of which intersected in the centre of the recesses.
This joint was not any simpler but the durability equalled that of the engine.
1.2.4.3 Bouchard’s One-and-a-half Times Universal Joint
Robert Bouchard developed the double Hooke’s joint for the front wheel drive
Citroën 15 CV car in 1934 (Fig. 1.12a). His experience led him 1949 to the idea of a
1 1 / 2 times quasi-homokinetic universal joint [1.16, 1.17].
The wide-angle fixed joint is built up symmetrically and consists of four main
parts (Fig. 1.16a): the two identical fork-shaped, parts 1, the two identical joint
crosses 2 which interlock and which have only three bearing journals each. Theses
are guided in standard bearing cups 3 and are thus able to support the same loads
and have the same durability as Hooke’s joints with needle bearings. The ball-shaped
design of the joint reduces the amount of axial space needed (Fig. 1.16b). The joint