The working principles of vehicle friction brakes
The most common types of brakes used in cars and motorcycles use friction to slow down the speed.
A prinsipal part of such brakes is some round object fixed to the inner parts of the wheels or at the wheel axix just near the wheels, which is spinning with the wheels, called the brake rotor. On newer cars this is usually a disc made of hard iron or a ceramic material. On older car models it used to be a drum made of iron.
Another principal part is something made of a ceramic material that is pressed against the rotor when the brake is used. This can be a caliper with ceramic pads tjat is squeezed around the bake disk or ceramic shoes inside a brake drum that are squeezed against the inner wall of the drum.
When so pressing,it makes friction that converts the rotating energy of the wheels to heat so that the wehicle slows down or stops. The heat is ventilated away by air surrounding the parts of the brake. If the ventilation is not well enough, the function of the brake decreases. Therefor a brake disk and other parts of the brake is formed in order to secure good ventilation.
There must be some mechanism that moves the parts that press against the rotor. This is often a piston with a cylinder connected to the pressing parts of the brake. The piston is moved fotrward by pumping oil into it. It is moved back with some spring mechanism.
The brake pedals are usually connected to another piston with a cylinder. This pumpes oil through a tube, calle a brake line, to the piston in the brkes. There will also be a container with oil connected to the cylinder under the pedal with at ube that ensures there is always enough oil in the system. There are valves in the cystem that ensures that oil always will go from the container to the brake system and tot the other way.
Modern cars usually also have a brake booster that helps the action of the brake. Usually the brake booster uses the difference of the pressure inside the manifold furnishing air to the motor and the outside air pressure to create a pulling force. The action of the motor pistons diminishes the air pressure inside the manifold, producing this difference that can be used to generate pull.
The principal part of the brake booster is a cylinder connected with a passage to the air manifold. The cylinder have a membran or a piston that is moved by this presure difference, and it has some mechanical connection or connection using brake oil to the brakes that help the braking action.
The working principles of electromagnetic brakes
An electromagnetic brake is an electric generator coupled mechanically to the wheels directly or indirectly. When used, an electric circuit connected to the generator is shut in, so that the generator makes electric current. The energy for making the current is taken from the motion of the wheels. The energy in the current must be led away somehow. The simplest way to do so, is a resistor connected in the current, so that the energy will dissipate as heat from the reistor. Usually however, the electric energy is stored in a battery for later use.
Electromagnetic braking is mostly used in hybrid cars. In hybrid cars, the electric motor will be switched in opposite direction and then used as a generator that will slow the motion, and the energy then stored in the battery of the car. This makes the car more economic too.
Cars that use some kind of electromagnetic braking system will also have friction brakes for more rapid reduction of speed.