Drum brakes are not as good as disc brakes, so why don't big trucks use disc brakes? You'll see!

In our daily driving, braking is an important part of the vehicle, which is related to our driving safety. There are two braking systems, one is disc brake and the other is drum brake. These two braking systems are basically suitable for most vehicles. As for the specific difference between them, I believe some riders are relatively clear. Disc brakes are mainly used in ordinary passenger cars, and drum brakes are mainly used in large trucks and buses. So is it better to go to chassis brakes or drum brakes?

The scientific name of disc brake should be called disc brake. Usually the main components of disc brakes are: brake cylinder, auxiliary pump, brake disc, brake caliper, brake disc, oil pipe, etc. When the vehicle needs to slow down, the brake calipers grab the brake disc and use the friction between the brake disc to slow the vehicle down, like holding a piece of paper between two fingers. Generally, cars use this type of braking.

Disc brakes have obvious advantages for heat dissipation. Most brake discs are made of steel, as they dissipate heat very quickly and have a distinct advantage when braking continuously, especially on downhill sections, where they still maintain sufficient stopping power after repeated braking. In the same situation, the drum brake will have a serious thermal decay of the braking force, and the possibility of weak braking or even brake failure will be felt.

Drum brakes have been used in automobiles for almost a century. In a nutshell, a drum brake is a brake that uses the friction of the static brake disc in the drum to generate friction with the rotation of the wheel to reduce the speed of the wheel. When the brake pedal is pressed, the force exerted by the foot causes the piston in the main brake cylinder to push the brake oil forward, creating pressure in the oil circuit. The pressure is transmitted to the brake pump piston of each wheel through the brake oil, and the brake pump piston pushes the brake disc outward, so that the brake disc and the inner surface of the brake drum are rubbed, and enough friction is generated to reduce the wheel speed, so as to achieve the purpose of braking.

Advantage

1. Lower cost: Drum brakes are the first type of braking system with a lower level of technology, so their manufacturing cost is lower than disc brakes.

2. The installation of the hand brake mechanism is very simple. Some models with disc brakes on the rear wheels will have drum brakes installed in the center of the disc brakes.

3. The drum brake has a good self-braking effect. The greater the external tension (braking force), the more pronounced the situation becomes. In addition to the low cost, large and small car drum brakes can only assist large pneumatic brakes, and small car drum brakes can assist vacuum. That's why big trucks still use drum brakes.

Lack

1. The diameter of the drum brake drum increases when heated, which increases the travel of the brake pedal and the braking response is smaller than expected. Therefore, when driving with drum brakes, thermal deterioration of the brake disc caused by high temperatures caused by continuous braking should be avoided as much as possible.

2. The braking system responds slowly, and the braking force is difficult to control, which is not conducive to high-frequency braking.

3. There are many complex components in the structure, and the brake clearance must be adjusted, which makes maintenance difficult.

As we all know, the biggest advantage of disc brakes is their sensitivity and heat dissipation. The braking force is relatively uniform and beautiful. As a result, disc brakes were previously only used on premium cars. Nowadays, the cost of disc brakes is getting lower and lower, and more and more disc brakes are used in domestic cars. Disc brakes are often used in domestic vehicles because they are usually light and require sensitivity over strength.

The biggest advantage of drum brakes is their strength. For a truck, the weight of the car itself is much higher than that of a family car, plus the weight of the goods being towed is also very large. The essence of braking is to "stand up", so if you want to stop a heavy truck, the braking force is much higher than the sensitivity requirement, so large trucks use drum brakes.

However, because the brakes of trucks are not sensitive enough, all drivers in the country should not rush to rush to the road when they see trucks on the road, especially some dangerous overtaking behaviors, which may lead to rear-end collisions. Although the rear end of the truck is entirely its responsibility, how can such a small body of a domestic car withstand such a large truck collision, and then it is not only our car that may be damaged.