In this system, a nut is meshed onto the worm gear by means of a continuous row of ball bearings.
As the worm turns, the nut moves up and down the worm threads.
The ball bearings not only reduce the friction between the worm and nut, but they greatly reduce the wear because the balls continually recirculate through the system, thereby preventing any one area from bearing the brunt of the wear.
The primary advantage of all worm-type steering systems is reduced steering effort on the part of the driver. However, due to the worm gear, the driver receives no feedback from the wheels.
For these reasons, worm-type steering systems are found primarily on large vehicles such as luxury cars, sport utility vehicles, pickup trucks, and commercial vehicles.
Functions of Steering:-
Achieve Angular Motion of Steering Wheels
Provide directional Stability of vehicle when going straight ahead
Minimize Tire Wear
Provide perfect steering condition
Transmit road feel to the driver’s hand.
Maintain correct amount of effort needed to turn the wheels.