For the purpose of slowing down or stopping a vehicle in time,drivers need a mechanical device to inhibit the motion of the vehicle.By utilizing friction between two surfaces applied together,the brakes used in most vehicles convert kinetic energy of the moving vehicle into heat.There are three major types of brakes that are typically applied to rotating axels or wheels.
Frictional, pumping, electromagnetic are the most common forms found in automobiles nowadays.
A.Frictional brakes are the most common type of brakes used in automobiles,which are formed by shoe and pads.Frictional brakes are composed of a rotating device with a stationary pad and a rotating wear surface.By using friction to stop the vehicle from progression,the frictional brakes can be be separated into three vital configurations.Brake shoes contracting to rub on the outside of a rotating drum is called a band brake. Drum brake is a rotating drum with shoes, which expand to rub on the interior of a drum.A disc brake is one that has a pad grasped on to a rotating disc. Ceramic brakes are high-end frictional brakes in which the rotors and brake pads are made of porcelain. This ensures better stopping capabilities with high resistance to heat. As ceramic brakes are very expensive, therefore it is not easily available as compared to metallic brakes.
B.Pumping brakes are commonly applied where a pump is included in part of the machinery. These brakes may use an internal-combustion piston motor to have the fuel supply cut off resulting in internal pumping losses to the engine creating braking.
C.Electromagnetic brakes are based on an electric motor that is already included in the vehicle. Most hybrid vehicles use an electric motor to charge electric batteries and regenerative brakes. Some buses use a secondary retarder brake which is a generator with an internal short circuit.