How Does Hydraulic Power Steering Work in a Car?
In the year 1952, General Motors introduced the fourth generation of the Cadillac Series 62. The exterior and interior were redesigned, the engine was modified, but what truly matters is that this specific Cadillac is considered the first production car with hydraulic power steering.
Power steering isn't just a way to make turning the wheel easier and increase driving comfort. It also has a significant impact on safety, as it greatly facilitates controlling the car when navigating turns at high speeds. It also significantly improves the likelihood of keeping the vehicle on the road in the event of a sudden failure of one of the steering wheels.
Components of the Power Steering System
The power steering system consists of several elements. These are the key components:
- Steering column: The construction of this device is complex, but its task is quite simple – to transmit force from the steering wheel directly to the steering rack.
- Steering rack: The role of the steering rack is to convert the rotational force from the steering column and turn the car's wheels to the desired angle.
- Hydraulic power steering pump: If the steering system is not equipped with power steering, the driver would have to exert a lot of effort to turn the wheels. The hydraulic power steering pump is a device that:
- Generates and changes fluid pressure in the system.
- Redirects hydraulic oil to the distributor, which, in turn, directs oil to the appropriate chamber in the hydraulic actuator.
These three units work closely together, so a failure in one component will be noticeable in the entire steering system. Loss of auxiliary power, wheel stiffness, knocking, and squeaking may indicate a malfunction in the steering system.
How Does the Hydraulic Power Steering Pump Work?
Firstly, it's worth mentioning that the hydraulic power steering pump is belt-driven, meaning it requires the vehicle's engine to be running.
Once the engine is started, the pump begins continuously pumping hydraulic fluid through the system.
Pumps for cylinders come in various types and designs, but the vane pump is most commonly encountered. It operates as follows:
- The rotating crankshaft of the running engine is driven by a belt to rotate the pulley wheel of the pump. The pulley wheel is attached to the shaft.
- On the opposite side of the shaft is a rotor with grooves in which blades are arranged. The blades are movable, so during the rotation of the shaft, they extend from the slots and press against the stator walls. The blades create a low-pressure zone in the chamber, causing hydraulic fluid to be sucked in and fill the chamber.
Approaching the narrow part of the stator, the plates re-enter their grooves, causing an increase in pressure. High pressure facilitates the squeezing of fluid into the pressure fitting and then to the distributor.
Distributors also come in various designs, but they most commonly have a valve insert that rotates when turning the steering wheel. The valve insert has holes and channels allowing fluid movement.
The role of the distributor is to direct the flow of fluid to the desired chamber in the hydraulic actuator, where a piston is attached to the gear rack. This creates pressure in one or the other chamber of the actuator, thereby reducing the force required to turn the steering wheel in one direction or the other.When the steering wheel returns to the neutral position, another element
is activated – the electromagnetic valve. When the power steering pump is not in use, the valve opens, and hydraulic fluid is released, causing a drop in pressure in the system.
Safety is in Your Hands
Power steering significantly improves the comfort and safety of the driver. However, the steering system is a complex mechanism composed of many elements and components. It requires attention and periodic servicing, just like any other system. Carefully observe your car's behavior, regularly check the quality and quantity of hydraulic fluid, and don't forget to replace it at the appropriate time.
If you suspect any issues with the power steering system in your vehicle, you should promptly schedule a diagnostic at a specialized workshop. A faulty element in the steering system can damage the remaining components. Don't delay the repair of the steering system; in this case, it's about safety.
If you have an issue with the steering system, STS can help. We offer a wide range of solutions: repairing the steering assembly or replacing it with a new, reconditioned original, or high-quality steering assembly. We diagnose and repair using our own production equipment.
