In the steering system, the steering wheel is the only portion that is directly controlled by the driver, while the rest of the system responds to the driver’s steering action.

Introduction

Controlling the direction of a vehicle can be done through various methods: direct mechanical contact (recirculating ball), rack-and-pinion steering gears, hydraulic power steering, or with the help of computers in some modern cars.

The steering wheel is also where you can find the car horn. It sometimes functions too as a control panel for cruise control and car audio controls to minimise the need for the driver to take his hands off the wheel. An airbag can also be placed inside the steering wheel to protect the driver in a frontal collision.

The steering action

The two most common types of steering gears are the rack-and-pinion and recirculating-ball steering systems.

Rack-and-pinion steering

This type of steering combines the steering box and centre link into one unit. The steering wheel, through the steering column, is directly connected to the rack. The rack contains a pinion assembly that moves a toothed piston to turn the steering gear.

One end of the inner tie rod is connected to either side of this piston and the other end is connected directly to the outer tie rod end. The inner tie rod end is threaded into the outer tie rod end and can be rotated to make adjustments during a wheel alignment.

The rack-and-pinion gearset converts the rotational motion of the steering wheel into the linear motion needed to turn the wheels and provides a gear reduction, making it easier to turn the wheels.

Recirculating-ball steering

The recirculating-ball steering gear contains a worm gear, which can be described as a block of metal with a threaded hole in the middle. This block has gear teeth on the outside to engage a gear that moves the pitman arm.

The steering wheel is connected to a threaded rod that fits into the hole in the block. When the steering wheel turns, it turns the bolt. The bolt is immovable so that as it spins, it moves the block, which in turn moves the gear that turns the wheels.

Power steering

The hydraulic fluid or power steering fluid which transmits the power in power steering makes it easier for the driver to turn the steering wheel. Most power steering systems have a belt-driven pump that provides hydraulic pressure. This hydraulic pressure is generated by a rotary vane pump driven by the vehicle’s engine.

When the power steering is not in use, for example, driving on a straight road, twin hydraulic lines provide equal pressure to both sides of the steering wheel gear. When torque is applied to the steering wheel, the hydraulic lines provide unequal pressure to help turn the wheels in the intended direction.