How a Vehicle Takes a Turn: Understanding the Mechanics and Principles Behind It

The act of turning a vehicle may seem simple, but it involves a series of intricate mechanics and principles that are critical for safe and efficient maneuvering. This article explores the fascinating mechanisms and principles behind a vehicle's ability to turn gracefully and accurately, from the basic turning of the steering wheel to the complex systems that make it all possible.

Basic Mechanics of Car Turning

When you're driving and need to make a turn, you sit in the driver's seat and see the steering wheel in front of you. This steering wheel is the key component that allows you to control the direction of the vehicle, and it works by turning the wheels on the front of the car. Here are the basic steps:

Drive at a moderate speed.

Turn the steering wheel slightly in the direction you want to go.

Apply the handbrake if necessary (though this is less common with modern power steering systems).

This action is fundamental to making the turn, but there are several underlying principles and mechanical components that make this process effective and safe.

The Ackerman Steering Principle

When you're turning a vehicle, you need to be aware of a fascinating and important fact: both the left and right front wheels do not turn at the same angles. If they did, the car would not turn; instead, it would carry its momentum forward and go straight. To achieve the desired turn, the car must obey the Ackerman steering principle, which is a geometric arrangement of linkages designed to ensure that the inner and outer wheels turn at the appropriate angles.

In layman's terms, the inner wheel should turn more tightly than the outer wheel to achieve the desired turn. Additionally, if a perpendicular line is drawn from the center of both the right and left wheels, this line should meet at a common point perpendicular to the rear wheels. This principle ensures that the vehicle can make a perfect turn. The following diagram explains this concept well:

This principle is made possible by the various mechanical components in the steering system, including the steering wheel, steering shaft, steering gear box, and steering arms or tie rods. These components work together to transfer the motion from the steering wheel to the steerable wheels of the car.

Modern Car Steering Systems

There are two main types of steering systems: manual and power-assisted. Manual steering systems rely on the strength of the driver to turn the wheels, while power steering uses a hydraulic or electric system to assist in turning the wheels. Today's most common system is the rack and pinion system, which offers simplicity and ease of use.

Rack and pinion systems operate with a direct gear-style connection between the steering wheel and the front wheels. In older systems, the steering wheel turns gears in a steering box, which uses a recirculating ball type system to move the Pittman arm left or right. The Pittman arm is connected to a centerlink with an idler arm holding up the other end of the centerlink. The ends of the centerlink are connected to tie rods, which turn the front wheels. This is a more complex system but is still widely used in many older vehicles.

Conclusion

Understanding the mechanics and principles behind a vehicle's ability to turn is crucial for both safe driving and a deeper appreciation of automotive engineering. By grasping the Ackerman steering principle and the various steering systems, you can better understand how your car manoeuvres around corners and why it is designed the way it is.