Describe Rack and Pinion type of steering. Explain the requirement of steering.

Requirements of steering:

• Steering system is primarily used to achieve the angular motion of the front wheels of a vehicle to negotiate a turn. This is done through linkage and steering gear which convert the rotary motion of the steering wheel into angular motion of the front wheels.
• The requirements of a good steering system are:
  • The steering mechanism should be very accurate and easy to handle.
  • The effort required to steer should be minimal and must not be tiresome to the driver.
  • The steering mechanism should also provide directional stability. This implies that the vehicle should have a tendency to return to its straight ahead position after turning.

Recirculating ball type 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.

Rack and Pinion Steering System:

• Figure shows the rack and pinion steering system.
• The rack and pinion steering system is simpler, lighter, and generally cheaper than worm-type systems.
• The steering column rotates a pinion gear that is meshed to a rack.
• The rack converts the rotary motion directly to side-to-side motion and is connected to the tie rods.
• The tie rods cause the wheels to pivot about the kingpins, thus turning the front wheels.
• Rack and pinion systems have the advantage of providing feedback to the driver.
• Furthermore, rack and pinion systems tend to be more responsive to driver input, and for this reason, rack and pinion steering is found on most small and sports cars.