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How does hydraulic power steering work?

A hydraulic power steering system is chosen for the controlled power and the ability to easily manoeuvre and steer a car no matter the weight. Within a hydraulic power steering system there are different components that need to be used to supply the extra power:

  • Steering fluid reservoir: Steering fluid is kept in its own tank and is supplied to the steering pump through rubber hoses. This is where the journey of the hydraulic power steering begins.
  • Steering pump: This is attached to the car engine next to the car alternator and the air conditioner compressor. It is connected to the car engine through a belt-pulley mechanism, and when the car’s engine is running this belt turns in a loop which helps to turn the steering pump. From here the pump pulls the steering fluid from its tank and pressurises it. This high-pressured steering fluid then leads the steering pump through the steering hoses and into the steering rack and into the rotary valve.
  • Rotary valve: This is positioned inside the steering rack. The rotary valve has strategically placed holes which redirects the steering fluid either back into the steering pump or into the steering rack. If the steering wheel is in its original position, the rotary valve will direct the fluid back to the steering pump, however when the driver turns the steering wheel the rotary pump opens up and the steering fluid from the pump gets directed, exiting the rotary valve through the fluid lines and into one of the hydraulic chamber of the steering rack.
  • Hydraulic chamber: when the fluid is directed into the chamber this is when power assist occurs. The hydraulic piston in the middle separates the hydraulic chamber into two equal portions, and it is here that the steering fluid is redirected, but not in equal amounts. With more fluid on one side of the chamber this creates a pressure differential across the chamber. The fluid then pushes the hydraulic piston towards the weaker side of the hydraulic chamber and the steering rack moves accordingly. This fluid differential is caused by the fluid dynamic, and this is what gives us the extra power. As both ends of the steering rack are connected to the car wheels, when the steering rack moves to the right so do the car wheels. This will allow the car to move in any direction.  

Through these four hydraulic components and with each one strategically placed, hydraulic power allows for smooth, easy and safe manoeuvring of large vehicle equipment not only on the road, but off road as well. Power Team SA knows the importance of hydraulic manoeuvred vehicles in industries such as mining, construction, railroad work, shipyards etc, so as to ensure that enough power is available and that, that power is under control through a system that ensures safety. For more information regarding hydraulics, and how hydraulic equipment can aid in your industry, Power Team SA are on hand to provide various solutions that are tailor made to suit different needs. Through years of experience, Power Team SA understands hydraulics, the components and the accessories that can be used to heighten any equipment.