A crown wheel is a wheel with cogs or teeth set at right angles to its
plane and the pinion is a small cogwheel that meshes with the crown
wheel. Crown wheel and pinion have excellent heat distortion control,
high strength, wear resistance property and noiseless and vibration free
operation. They are made of fine-grained steel billet.
The pinion thread is specially made on the thread grinder to ensure proper fitting. Tooth contact of a crown pinion is inspected on a Gleason machine at regular intervals of time for uniform hardness and adequate case depth. They are checked thoroughly for high spots because this ensures premature failure and noise-free operation. The crown wheel & pinion are paired and checked for centralized tooth bearing and desired proximity. An elliptoid contact pattern is ensured between the crown wheel and pinion.
In a machine, when any torque is applied to the drive unit, the tendency is for the crown wheel and pinion to be forced into or out of mesh by the sliding contact. The amount of pre-load on the bearings determines how much torque can be transmitted without allowing end float, which cause the meshing of the gears to become incorrect.
Crown wheel & pinion are used widely in automotive industries. They are one of the most stress prone parts of a vehicle. They are used in automobiles to maintain forward motion. To maintain forward motion both output drive shaft sides covers are removed and the pinion and crown wheel are swapped completely with differential.