Ever thought how it all works when you are using a steering wheel? When you turn the wheel right, the wheels turn right and when you turn it left the wheels turn left. This might seem like it is caused by a simple mechanically adjusted reaction, but what actually happens inside is a bit more complicated than that. A steering mechanism in a vehicle enables the vehicle to move in directions other than forward and back. Since this is an inevitable maneuver, all vehicles have it. Here’s how it works.
Steering mechanisms are of three kinds – Rack and pinion, recirculating ball and power steering. Rack and pinion and recirculating ball are different kinds of steering mechanisms, but power steering is only an adjustment on both. So, power steering could either be of the rack and pinion type or of the recirculating ball type.
Rack and pinion
The rack and pinion is a very simple mechanism of steering. It is the most commonly seen steering mechanism and it uses the technique of rack and pinion to steer the wheels.
The steering shaft connects the steering wheel to the pinion gear. The shaft rotates with the steering wheel and rotates the pinion gear. The pinion gear in turn rotates the rack and the tie rods at the end of each rack are connected to the steering arm and the spindle.
When the driver turns the steering wheel right, the pinion wheel rotates and thus moves the rack left or right. This sideways movement pushes the right steering arm to the right and pulls the left wheel towards the same direction. Due to this, the wheel makes a rotational movement towards the right, horizontally about its central axis. This means the wheels turn to the right and as the vehicle is pushed forward by the engine, it moves towards the right.
There are calculations about how much the wheel would turn for a certain angle of turning the steering wheel. For example, if you finish one complete revolution of the steering wheel, and if the wheel turns by 20 degrees, then the steering ration is 360/20 = 18:1. Steering ratio depends on the kind of vehicle in question. A high steering ratio means, one has to turn the steering wheel more to turn the wheel to a certain angle.
Sports cars have a low steering ratio in order to reduce the amount of hand movement and to have a quick response. Since engines are light, one does not have to use a lot of strength in steering the wheel.