|
What is Universal Joint? The suspension connects the final drive assemblyto the car body. The final drive moves up and down inrelation to the engine and transmission. A coupling isneeded that permits movement between the final driveand transmission. The universal joint provide thiscoupling.
Here two U-shaped pieces are placed perpendicular toone another and joined with a simple cross. The U-shapedpieces are called yokes. The cross that connects them iscalled a spider. The arms that extend from the spider arecalled trunnions. The two yokes are at a 90o angle to oneanother. Most cars have two universal joints, one at eachend of the propeller shaft.
A shaft which receives the drive from a cross typejoint varies its speed during rotation; the greater thedrive angle the greater the speed variation. A constantrotational speed can be restored by fitting a secondjoint in a way such that when the first joint increasesits speed the second joint decreases its speed.
The hypoid gear is in common use today duemainly to the fact that the offset pinion allows thepropeller shaft to be set below, (for cars) or above, (forcommercial vehicles) the crown wheel center. Thisgives either a reduction in the propeller shaft tunnel,which causes a bump in the vehicle floor, or in thecase of a commercial vehicle a reduction in the anglethrough which the universal joint has to operate.
|
WH78