Cardan Shaft

(named for G. Cardano), a device in motor vehicles for the transmission of rotation from a driving shaft to a driven shaft when the shafts are at an angle to one another. The angle and distance between the shafts often change continuously during operation.

In motor vehicles, a Cardan shaft is used to connect the motor and transmission (at an angle of up to 5°), the transmission and transfer case (at an angle of up to 5°), and the transmission or transfer case and the rear-axle drive (at an angle of up to 15°), as well as in steering gear or winch drive.

A Cardan shaft consists of a propeller shaft with two (less frequently one) Cardans. If the propeller shaft is connecting mechanisms between which the angle and distance vary (for example, the transmission and rear-axle drive of a motor vehicle), overhang balance is provided in the form of a slip splined joint, which makes possible a change in the length of the shaft within set limits. Depending on the angle between the propeller shafts in a Cardan shaft, rigid or flexible semi-Cardan joints, full Cardans of unequal angular velocity, or Cardans of equal angular velocity may be used. Full Cardans, which have two jaws, needle bearings, a spider, mounts for the spider journals, and a tightening mechanism, are the most commonly used type. The efficiency of a single Cardan is 0.985–0.99.