Hydraulic Brake - An Example of A Hydraulic Brake System

An Example of A Hydraulic Brake System

Hydraulic brakes transfer energy to stop an object, normally a rotating axle. In a very simple brake system, with just two cylinders and a disc brake the cylinders could be connected via tubes, with a piston inside the cylinders. The cylinders and tubes are filled with incompressible oil. The two cylinders have the same volume, but different diameters, therefore a different surface areas. The one with the smallest diameter is called the master cylinder. The spinning disc brake, will be placed down at the piston with the larger surface area. Let us say that the diameter of the master cylinder is half the diameter of the slave cylinder, so the master cylinder has a surface area which is four times smaller. Now, if the piston in the master cylinder is pushed down 40 mm, with 10 N of force, the slave piston will then move 10 mm, with a force of 40 N.

This force can be further multiplied by adding a lever connected between the master piston, a pedal, and a pivot point. If the distance from the pedal to the pivot is three times the distance from the pivot to the connected piston, then it multiplies the pedal force with a factor of 3, when pushing down on the pedal. Now, if we push down on the pedal 120 mm with 10 N of force, 30 N will then be applied to the master piston, and the slave piston will then push 10 mm against the brake pad, with a total force of 120 newton.