One of the important human interface systems in the automobile is the steering gear.
The steering gear is a device for converting the rotary motion of the steering wheel into straight line motion of the linkage.
The steering gears are enclosed in a box, called the steering gear box.
The steering wheel is connected directly to the steering linkage it would require a great effort to move the front wheels. Therefore to assist the driver, a reduction system is used.
The different types of steering gears are as follows:
Worm and sector steering gear.
Worm and roller steering gear.
Cam and double lever steering gear.
Worm and ball bearing nut steering gear.
Cam and roller steering gear.
Cam and peg steering gear.
Recirculating ball nut steering gear.
Rack and pinion steering gear.
Recirculating ball system steering system:
Figure shows the recirculating ball system.
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.