Steering Rack and Pinion

Steering Rack and Pinion – Control and Precision

We often take our ability to steer and control our car for granted, and when something goes wrong with the system, it can be hard to understand why it costs so much to repair. If you think you might ever like to be able to work on your car's steering system yourself someday, you will have to become very familiar with how steering rack and pinion style achieves its control and precision. Although it was not the original way that steering was achieved in early cars, most manufacturers have now switched to rack and pinion steering because of its superior design.

If you were to get under your car or truck to look at the steering system, you would notice that the steering rack and pinion is not a very complicated mechanism. The whole system consists of a rack and pinion gear set that is contained in a tube made of metal. Both ends of the rack system protrude from the tube where it connects with the rod or tire rod. The pinion, which kind of looks like a small, horizontal gear, attaches to the steering shaft where it enables the steering wheel to control the motion of the tires.

Whenever you make an adjustment to the steering wheel, and tell the car to travel in a certain direction, a certain chain of events must occur to transmit this message from the inside of the cab to the tires below. First the movement on the steering wheel causes the pinion to spin, which in turn causes a growth or retraction of the steering rack and pinion. This in turn is connected to the wheel spindle, and as such controls the motion of the tire when a command is given through the steering wheel. In this way, the mechanism performs two functions that were very difficult for early car engineers to achieve so seamlessly.

First of all the steering rack and pinion is able to translate the rotational motion of the steering wheel inside the car into a lateral motion that can be used to send commands to the tires. Also, it requires less gears and moving parts to be able to turn the wheels, making the motion of turning the wheels a much easier process. You may have already noticed, but on modern cars, it only takes three or four complete steering wheel revolutions to turn the wheels all the way to the left or right.