What is rack and pinion steering in simple words

The steering rack on the car and how it works

The rack and pinion or as it is called – pinion steering rack – modern cars are incredibly common control system for the front wheels. Even if you are not a guru in automotive technology, you probably have heard about this mechanism. But how does it work? Explain the principle of operation for beginners, what is called on your toes.

Most likely, your vehicle is rack and pinion steering. Due to this incredibly popular engineering choice progressive work of the whole system (perfect for today’s dynamic, fast and powerful cars), good feedback from the front wheels (you know at what angle the wheel is turned and how fast is their turn) and the ability to install control on cars with front independent suspension.

So how does the steering rack?

Fortunately, the basics is not difficult to understand even the novice motorist. It’s all in the principle of conversion of rotary motion into linear. In other words, when you turn the steering wheel, you turn the steering column, which in turn cranks connected with it the steering shaft and the so-called worm gear located on the end of the shaft:

This gear is mounted on the rail, which in turn consists of metal parts coated with teeth with a certain step, and engages the gear. As the gear rotates, the rack moves left or right, depending on where you turn the wheel. Steering rod rack attached to the wheels by means of pins.

A simplified diagram of rack and pinion steering: steering Wheel (1); a Steering shaft (2); Rack pinion steering shaft (3); the tie rod (4); wheel Hub or steering knuckle (5)

This is a simple but effective system that does not have the disadvantages inherent in vitoriana type of drive the front wheels. In turn, vinereanu type typically adds more weight to the car, requires a lot of effort while driving and often has a “dead zone” in the Central part. In our days the last type of steering is commonly used on more cumbersome and less fast vehicles – trucks and buses.

What other elements are inextricably linked to the steering rack?

Another element is always installed on all modern cars, along with the mechanism of rotation of the wheels – amplifier, which facilitates the rotation of the steering wheel. The system may be driven as by means of hydraulics (such a rack is called hydraulic) and electric motor (respectively, an electric steering rack).

Gur

In the first case, the element power steering (Gur), power cylinder, is mounted on one side of the steering rack along it. A piston with a hydraulic actuator and a rotary valve directing hydraulic fluid to the right or left side of the piston depending on the direction of rotation of the steering wheel increases the pressure on the piston and reducing the force needed to “stretch” the rail from side to side.

Actuators

Electric power steering system is now actively replacing the familiar hydraulic actuators. Pump, valves and pistons are replaced by electric motors: the steering rack in the steering column or shaft, they can be installed everywhere. Despite the fact that electronica safer and easier, while motorists dislike her. Why? They say that there are no logical and clear feedback when the wheel rotates. That is, during the rotation of the steering wheel, as some owners seem to live their lives, it is not clear, for example, at what angle they are rotated, the handlebar is too “light” and “empty”.

Most likely the automakers will solve this problem, the more they have quite diverse unused in this direction Toolkit. For example, ease of driving depends on the change of the transmission ratio of the steering mechanism and the mutual arrangement of teeth on the rail. Want to slow down the rotation change rate. On some steering racks teeth in the middle are closer to each other, the edges away from each other. It supports the management in the Central position of the steering wheel at a comfortable level of accuracy and speed which becomes faster with increasing steering angle.

There are more complex systems that change the ratio. They added additional controls, often between the steering shaft and the gear. For example, this often can be an additional electric motor, which allows to vary continuously the speed and force on the steering wheel.

So, next time you turn the wheel of your car, you’ll know what’s going on. Maybe not the most appealing area of automotive technology, but without it we would not be able to spin the wheel “one finger”, while constantly monitoring everything that is happening with the front wheels of our car.