Brakes are an integral part of every car, used to slow down, stop, and warn traffic after a stop. Driving safety depends on the availability and quality of the braking system. Drum and disc brakes are used in cars. How are they different? Why is the use of discs so tightly formed the basis of modern automotive industry?
Comparison of drum and disc brakes
Both types of brakes are of the wheel type. Most manufacturers equip the front wheels of passenger cars with disc brakes, and the rear ones with drum brakes. Trucks and buses are equipped with drum brakes, which have the effect of self-reinforcement and are compatible with a pneumatic drive.
The drum brake system was previously installed on all wheels of the car. The principle of its operation is as follows. The piston pushes the pad out under the influence of hydraulic pressure. The friction material of the pad slows down the rotating brake drum by contacting its inner side. The brakes are applied and the car stops.
However, the reels have their limits. When heated, their productivity is lost. This is especially noticeable when driving at high speed. The efficiency is also reduced due to the formation of gases, when the pads and the drum interact. Experts tried to remove heat from the drums using aluminum and cooling fins. But these changes did not bring the proper result.
Disc mechanisms are increasingly used in the automotive industry. Their high stability during operation is affected. The difference in the principle of operation is only that the friction material is adjacent not to the drum, but to the disc. When the brake is heated or moisture gets on the friction surface, there is only a slight decrease in braking efficiency. In addition, they have less weight, cool down better, and react faster to pedal pressure.
Disc brakes are open to access, which has its advantages and disadvantages. Dirt, water, dust – everything that interferes with the operation of the drums, the discs are discarded during rotation. On the other hand, these elements still end up on the disk, which leads to its wear. Thin products crack under extreme conditions. The mechanisms of the rear wheels are more affected.
Currently, disk mechanisms are being released with additional functions. Ventilated discs are most often placed on the front wheels. They have two friction surfaces separated by jumpers. This plays an additional role in heat dissipation. Another form of manufacturing involves perforating discs. The holes take over the bulk of the dirt, preventing it from clogging between the discs. At the same time, the speed of the brakes increases.
Amplifiers and drives
The pneumatic drive has found its wide application in the designs of tractors, buses and trucks. Its appearance is associated with an increase in traffic intensity and increased speeds. The braking process is carried out by compressed air. They produce combined types: electropneumatic (used in trailers) and hydropneumatic (long-wheelbase cars and electric train tractors).
The vacuum booster was originally used in electric trains. Now almost all modern cars are equipped with it. When the brake pedal is pressed, it triples the force of the driver’s foot. Braking is carried out due to the pressure difference in the two chambers of the amplifier.
Thus, there are only two types of brakes used in the automotive industry today. Some motorists consider the optimal combination of drum and disc brakes in one car. However, gradually the discs are replacing the drums, being a more modern and high-quality type of brakes.
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