The wheel is considered as the most important invention made by mankind. It made travel to long-distance possible and allowed us to spread far and wide. To control the wheels and make the travel easier, the steering system was implemented. Today we will explain how a car steering system works and how the simple act of turning your steering wheel makes the car corner.

Read More: SOHC & DOHC Difference | Overhead Cam Configuration Explained

Types Of Steering System

Before we head into the explanation there are currently two major types of the steering system. The commonly used Rack and Pinion System and the conventional system know as the Recirculating Ball Steering System. We will explain both in brief and also how the power-assisted steering system works which is commonly called the power steering.

Rack And Pinion Steering System

The most common steering system, the rack and pinion gets its name from the two gears it uses, the rack (the linear gear) and the pinion (circular gear). This system is used in most of the cars and is usually not employed in heavy-duty vehicles. Its working may appear complex but uses quite simple physics.

Construction Of A Rack And Pinion

Rack and Pinion
Rack and Pinion

The steering wheel has a shaft attached to it and on the other end of the shaft is the pinion. The pinion is positioned on top of the rack and moves when the steering wheel is moved. The end of the rack has something called a tie rod. The tie rods connect to the steering arm which in turn is connected to the wheel hub. Onwards to the working of rack and pinion.

Download The GoMechanic App Now!

banner

Working 

When you rotate the steering wheel the shaft rotates along with it. This in turn rotates the pinion which is on top of the rack. The rotation of the pinion makes the rack move linearly moving the tie rod. The tie rod connected to the steering arm then causes the wheel to turn.

The size of the pinion affects how much turning you get. If the pinion is large in size it means that you’ll be getting more turn from less steering wheel rotation which will make it harder to control. On the other hand, a smaller pinion means it’ll be easier to control but you will need multiple steering wheel turns to make the car corner.

This is how the Rack and Pinion System works. It is a simple device however it can use multiple complex and advanced systems that can make it even better to use.

Recirculating Ball Steering System

Known with multiple names such as the worm & sector and recirculating ball & nut, this steering system is usually found in old cars and heavy-duty vehicles like trucks. It’s working is different from a rack and pinion. Let’s see the construction of the recirculating ball steering system before we explain the working.

Construction 

recirculating ball steering system
Recirculating ball steering system

The recirculating ball steering system has two gears, the worm gear and the sector gear. The steering wheel is connected to a threaded shaft which is connected to a block. The worm gear is quite big and goes through the block which is threaded in such a way it allows the worm gear inside. This block has gear teeth outside of it to which the sector gear is connected. This sector gear is then connected to the pitman arm while the pitman arm is attached to the tie rod. There are ball bearings inside the block that fill the thread of the worm gear. The working is simple just like rack and pinion.

Read More: Remembering The Fiat Petra: A Lesser-Known Successor of The Fiat Siena

Working

When the steering wheel is rotated the shaft connected to the steering rotates as well. The gear is bolted to not move up and down. This makes the block and the worm gear rotate.  The rotation makes the block move as it is not held down by anything. The moving block then moves the sector gear which in turn moves the pitman arm. The thread of the worm gear is filled with ball bearings which reduce friction and prevent the slop in gear.

This is how the recirculating ball steering system works. It is rarely used now and is mostly found in trucks.

With the explanation of both steering system done we now move on to the power steering system which is not a steering system in itself but the support option that helps both of these steering systems by reducing the work the driver would need to do.

Popular Read: DCT vs CVT vs AMT | Choose The Best Transmission

Power Steering System

This system has single-handedly made steering of a vehicle a cakewalk.  We will discuss the power steering employed by the rack and pinion steering system in brief.

Power assisted rack and pinion
Power-assisted rack and pinion

The power steering adds some more parts to the rack and pinion system which makes it easier to use. Mainly the pump, pressure tubes, rotary control valve, fluid lines and a hydraulic piston.

The job of the pump is to as you might have guessed, pump the fluid around when needed. The rotary control valve ensures that the movement of fluid is only performed when the driver is actually steering the car. The hydraulic piston moves around depending on which fluid line brings the high-pressure fluid. This piston movement on the rack makes it easier for the driver as it is applying most of the force necessary to steer the car. This concludes the brief discussion on how a hydraulic power steering system works.

GoMechanic Blog on Google News

Leave a Reply