Power Steering Systems

Power Steering Systems

The car’s ability to move left and right is provided by the steering system. The rotational movement of the steering wheel by hand is transmitted to the front wheels by means of a gear. The front wheels are turned with the help of the arms parallel to the direction of rotation. Turning is provided with the help of electric, gear or hydraulic steering systems, although no manual force is applied.

How Does the Steering System Work? (Working Principle of Steering System)

The rotational movement from the steering wheel is transmitted to the wheels by turning the steering gear into linear motion and increasing the force, thereby steering the wheels. The torque (torque) obtained from the steering wheel is transmitted to the steering gear via the steering shaft. Steering shaft rotates the pinion gear in the steering gear, pinion gear; the rack is made up of milled channels opened on a straight shaft. Thus, as the pinion gear rotates (circular movement), it will move left and right to the rack (linear movement), with the tie rods (tie rods) connected to the end of the rack, this linear push-pull movement is transmitted to the wheel axle carrier with tie rod heads, the wheels are rotated.

In transferring the traction force to the road, which enables the vehicle to advance; transferring the braking force to the road that causes it to stop-decelerating and rotating the wheels by means of the steering system enabling it to be directed; the friction force between the tire and the road is utilized. If there is no friction force; does not progress, does not stop, does not rotate.
Steering the vehicle in a good way; factors such as road condition, coefficient of friction between the tire and the road, speed of the vehicle, aerodynamic effects (lateral winds), impact-impact to the vehicle while driving. The system must be able to cope with adverse effects and ensure safe driving.

Mechanical Steering System Parts

Steering – Driving Feel: In the  steering system, the force transmission is from the steering wheel to the wheels, while at the same time a counter-force, which is created by the influence of road and driving conditions, is transferred from the wheels to the steering wheel, called the steering-driving sensation.

What are the types of steering systems?

Types of Steering System in Terms of Structure:


• Mechanical Steering Systems (Worm Screw Type or Pinion Rack Type)
• Hydraulic Steering Systems
• Electrohydraulic Steering Systems (Oil Pump Electric)
• Electromechanical Steering Systems (Electric Steering System)

Steering gear box types  

 Pinion Rack and Pinion Gear Box  (Most widely used in Passenger and Light Commercial Vehicles)
Worm screw type steering gear box  (Bus-trucks)
-Internal screw and gear type roller,
-Internal screw and finger type roller,
-Internal screw and rotary ball nut type (truck, bus, tractor, heavy-duty vehicles, the most widely used type)
Today, the most widely used pinion rack and pinion gearboxes, hydraulic and electric steering systems have been added as an auxiliary system.

What are the tasks of Power Steering Systems?

* Easy steering of the vehicle in the desired direction.
* Good maneuverability. Quick, easy and safe turning of the vehicle on narrow and winding roads.
* Requires proper steering effort. The force required to turn the steering wheel should not be too much. The steering wheel is soft when the vehicle is stationary or driving slowly; It must be hard when going fast.
* Self-recovery of the steering wheel. If the steering wheel is released slightly after turning, it should automatically return to the straight-ahead position.
* Impacts from the broken road surface, do not disrupt steering and ensure safe driving.

Steering systems are designed in various connection types, depending on vehicle type and suspension system type. Parts and locations of the system vary. Two of the most commonly used steering system connections are shown below.

Independent Suspension and Steering Linkage

Independent suspension (macpherson or double wishbone) is used on the front wheels of passenger and light commercial vehicles, driving comfort and performance are good, load carrying capacity is low. In this system, the wheel-chassis connection; wheel-axle carrier, swing arms, shock absorbers and springs, in the form of chassis. Steering (rotation) of the wheel; the steering link arms (long and short rods) rotate the axle head (axle carrier).
Macpherson suspension system; the lower swing ball joint and the upper suspension mast (shock-spring) takes place around the axis.
In the front suspension system with double wishbones; wheel rotation occurs about the axis of the lower and upper swing linkage ball joints.

Fixed Suspension and Steering Linkage

Used in the fixed suspension (axle-shear-shock absorber) of the front wheels of heavy commercial vehicles (truck-tractor). Less comfort but very high load carrying capacity is achieved. Because the front wheels use a fixed axle (fixed axle), the wheels rotate around the thick pins (axle pin or king pin) on the axle heads. The wheel is connected to the hub, the hub is mounted on the axle (axle carrier), the axle head rotates around the axle pin.
The steering system of a vehicle with fixed front suspension (eg truck) has a “tie rod bağlantı that allows the left and right wheels to turn together. Thus, when the steering gear rotates the left wheel, this long rod enables the rotation of the left wheel to the front right wheel.
Rectangular structure consisting of axle (fixed axle), long tie rod and tie rods is called steering trapeze.

4ws system

Four-  wheel steering is a system that improves handling on corners, ensures safe and easy overtaking of vehicles at high speeds, and facilitates city maneuvers and parking.

The first  4ws  system was applied in 1905 on a Lotil brand tractor. Honda introduced mechanical control in 1987 and Mazda introduced electronic control in 1988.

Working

When we break the front wheels to the right or left, the rear wheels turn right or left by 1 / 5th of the front wheels, preventing the rear of the car from escaping out of the bend. At high speed, the rear wheels rotate in the same direction as the front wheels in the opposite direction at low speeds.

Applied tools

  • Honda Prelude
  • Honda Accord
  • Mazda 626 GT
  • Mitsubishi Galant
  • Lemon Xantia
  • Citroen XM
  • Lemon Zx
  • Citroen Xsara
  • Citroen C5 (before 2008)
  • Citroen BX
  • Citroen CX
  • Renault Laguna
  • Audi Q7 (2015-2016)
  • Renault Talisman (over 130 hp)

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