Steering System: Definition, Overview, and Parts

What is Steering System?

Steering is a system of components, linkages, etc. that allows a vehicle to follow the desired course. An exception is the case of rail transport, by which rail tracks combined with railroad switches (also known as ‘points’ in British English) provide the steering function. The primary purpose of the steering system is to allow the driver to guide the vehicle.

The steering system converts the rotation of the steering wheel into a swiveling movement of the road wheels in such a way that the steering wheel rim turns a long way to move the road wheels a short way.

The system allows a driver to use only light forces to steer a heavy car. The rim of a 15 in. (380 mm) diameter steering wheel moving four turns from full left lock to full right lock travels nearly 16 ft (5 m), while the edge of a road wheel moves a distance of only slightly more than 12 in. (300 mm). If the driver swiveled the road wheel directly, he or she would have to push nearly 16 times as hard.

The steering effort passes to the wheels through a system of pivoted joints. These are designed to allow the wheels to move up and down with the suspension without changing the steering angle.

They also ensure that when cornering, the inner front wheel – which has to travel around a tighter curve than the outer one – becomes more sharply angled.

x
Engineering Choice | The biggest engineering Blogs

The joints must be adjusted very precisely, and even a little looseness in them makes the steering dangerously sloppy and inaccurate.

There are two steering systems in common use – the rack and pinion and the steering box.

On large cars, either system may be power-assisted to reduce further the effort needed to move it, especially when the car is moving slowly.

Types of a Steering system

There are two types of steering systems available. They are:

  • Hydraulic
  • Electric/electronic

1. Hydraulic Steering system:

Hydraulic power steering systems work by using a hydraulic system to multiply the force applied to the steering wheel inputs to the vehicle’s steered (usually front) road wheels.

The hydraulic pressure typically comes from a generator or rotary vane pump driven by the vehicle’s engine. This is known as the Hydraulic Steering system.

2. Electric/electronic Steering system:

Electric/Electronic Steering system is also known as the power steering system. In motor vehicles, a power steering system helps drivers steer the vehicle by augmenting the steering effort needed to turn the steering wheel, making it easier for the vehicle to turn or manoeuvre.

Electric power steering systems use electric motors to provide assistance instead of hydraulic systems. This is known as the Electric/electronic steering system.

Parts of the Steering system:

The parts of the Steering system that are available are:

  • Ball Joints
  • Bushings
  • Sway Bar Links
  • Center Links
  • Idler Arms/Pitman Arms
  • Rack and Pinion Units
  • Tie Rod Ends/Sleeves
  • CV Joints/Boots
  • CV Axle Half Shafts
  • Shock Absorbers
  • Struts/Cartridges

These are the parts of the steering system.

Components of a Steering system:

The components of a steering system are listed below. They are:

  • Steering wheel
  • Steering column or shaft.
  • Steering gear
  • Drop arm or pitman arm
  • Ball joints
  • Drag link
  • Steering arm
  • Stub axle
  • Left spindle and kingpin
  • Left tie rod arm

1. Steering wheel:

The steering wheel is the control wheel to steer a vehicle by the driver. It contains a traffic indicator switch, light switch, wiper switch, etc. It is also called a driving wheel or a hand wheel is a type of steering control in vehicles.

Steering wheels are used in most modern land vehicles, including all mass-production automobiles, as well as buses, light, and heavy trucks, and tractors.

2. Steering column or shaft:

The Steering column also known as the shaft is fitted inside the hollow steering column. When the steering wheel is turned, the steering shaft will also be rotated. Due to this, the motion is transmitted to the steering box.

The steering column is located at the top of the steering system and attaches directly to the steering wheel. The steering column then attaches to the intermediate shaft and universal joints.

3. Steering gear:

The pitman’s arm is splined to the steering gearbox rocker arm at one end and the other end is connected to the drag link by a ball joint.

The steering gearbox contains the gears that transmit the driver’s steering inputs to the steering linkage that turns the wheels, and it multiplies the driver’s steering changes so that the front wheels move more than the steering wheel.

4. Drop arm or pitman arm:

When the steering wheel is turned right or left the pitman transmits the motion it receives from the steering gearbox to the tie rod. A “drop pitman arm” is used to correct the steering when a vehicle has a suspension lift.

5. Ball Joints:

The ball joints are spherical bearings that connect the control arms to the steering knuckles. The bearing stud is tapered and threaded and fits into a tapered hole in the steering knuckle. A protective encasing prevents dirt from getting into the joint assembly.

6. Drag link:

The drag link converts the sweeping arc of the steering arm to linear motion in the plane of the other steering links. “The drag link connects the pitman arm to the steering arm, or in some applications, it connects to the tie rod assembly.

7. Steering arm:

The steering arm is an arm for transmitting the turning force from the steering gear to the drag link, especially of an automotive vehicle.

The basic function of the steering system is to allow the driver to safely and precisely steer the vehicle. Beyond this, the steering system also provides a way to reduce driver effort by making the act of steering the vehicle easier.

8. Stub axle:

When the steering wheel is rotated, the motion is transmitted to the pitman’s arm through the gearbox. This motion is transmitted to the drag link. Drag link transfers this movement to stub axle which rotates about kingpin. This turns the right wheel.

9. Left spindle and king arm:

In automotive suspension, a steering knuckle is that part that contains the wheel hub or spindle and attaches to the suspension and steering components. It is variously called a steering knuckle, spindle, upright, or hub, as well.

The wheel and tire assembly attach to the hub or spindle of the knuckle where the tire/wheel rotates while being held in a stable plane of motion by the knuckle/suspension assembly.

10. Left tie rod arm:

The right- and left-side tie rods are connected to each other by a center link, which is also mounted to the Pitman’s arm on the steering gear and the idler arm on the passenger side of the vehicle.

Rack and pinion steering are currently the most predominant of the two steering linkage systems.