How Does Power Steering Work?

Steering a vehicle used to involve a good bit of muscle, but not anymore thanks to power steering. So, how does power steering work exactly?

Power steering was originally introduced not to the car market, but the truck industry. The reason had to do with the physical effort required to turn a large, heavy truck. This was particularly problematic when the truck was barely moving as the effort involved was massive. Power steering made things much easier and it soon occurred to someone that using it for cars would make sense as well. There are three types used on the road today. Let’s take a look.

Rack and Pinion Steering

Rack and pinion power steering is by far the most common system used. Your steering column connects to a linkage that connects to a pinion. The pinion is a metal rod that has grooves in the end of it like a gear. This then sits on a rack. When you turn the steering wheel, the pinion turns and the rack moves right or left as appropriate. The rack is then connected to tie-rods on most cars. The tie-rods are connected to the wheels and turn the vehicle. A hydraulic piston or electric motor is used to amplify the turning motion of the piston and move the rack far more easily than one would do if just trying to muscle the car through a turn.

Steer By Wire

Steer by wire is the latest approach in our digital world. The “wire” in the name does not refer to a metal cord, but to a digital signature much like wireless internet. In this system, there is no direct physical connection between the steering wheel and wheels. There is simply a computer monitoring the input you give to the steering wheel. This is then communicated electronically to a computer on the rack that uses a power unit to move the rack and turn the car. This is a very new version of power steering.

Recirculating Ball Steering

This system is commonly used on larger SUVs. It works by connecting the steering shaft into a box. The end of the steering shaft has grooves. There is no rack. It is replaced by a rod running between the wheels. The rod is connected to a pitman arm. The pitman arm is connected to a gear inside the box the fits in the grooves of the steering arm. When you turn, the steering arm spins and moves the pitman arm gears up or down and the rod between the tire rods move back and forth. Hydraulic systems help power this action by adding a piston to the movement.

Power steering has made modern driving a breeze. Even the tinniest of us can drive a monster SUV with the least of effort. 

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