Is disc brake better than drum brake? Why don't big trucks use disc brakes?
TIME：2020.02.19
Is Disc Brake better than drum brake? Why don't big trucks use disc brakes? In Our daily driving, the brake is a part of the vehicle can not be ignored, it is related to our driving safety. Brake system is divided into two main, a disc brake is a drum brake. The two kinds of braking system basically covered most of the vehicles, as for their specific differences, I believe that some car friends or more understanding. Disc brakes are mainly used for normal passenger cars, while drum brakes are mainly used for large trucks and passenger cars. So is disc brake or drum brake good? DISC brake scientific name should be called disc brake, usually the main components of disc brake are: Brake Master Pump, sub-pump, brake disc, Brake Caliper, brake pad, oil pipe and so on. When the car needs to slow down, the brake caliper will grip the disc and slow it down by rubbing the pad against the disc, just as you can grip a piece of paper with two fingers. This is the way cars normally brake. The disc brake has obvious advantages in heat dissipation. Most of the brake discs are made of steel, because they dissipate heat very quickly, they have obvious advantages in the process of continuous braking, especially in the downhill section, enough braking power will still be maintained after a series of brakes. Drum brake in the same situation there will be more serious thermal attenuation of braking force, will feel brake weakness, and even there will be a potential brake failure. Drum brake is a scientific name for drum brake, which has been applied to automobiles for nearly a century. In simple terms, drum brake is the use of brake pads that are still inside the brake drum to rub against the brake drum as the wheel rotates, a braking device that produces friction to reduce the rotation speed of a wheel. When the brake pedal is pressed, the force exerted by the foot will cause the piston in the brake master pump to push the brake oil forward and generate pressure in the oil circuit. The pressure is transmitted to each wheel by the brake fluid, which pushes the brake pad outward, causing friction between the pad and the inner surface of the drum, and generating enough friction to slow down the wheel, for braking purposes. Advantage 1, lower cost: Drum brake manufacturing technology level is lower, but also first used for braking system, so manufacturing costs than disc brake. 2. The handbrake mechanism is easy to install. Some models with disc brakes on the rear wheels have a drum brake with a hand brake in the center of the disc. 3, drum brake has good self-braking function, because the brake to make the outside of the piece, the wheel rotation with the outside of the brake drum distortion of an angle of course not so large that you can easily see the brake to make the outside of the piece tension brake more power, the situation is more obvious, therefore, generally large vehicles or the use of drum brake, in addition to lower costs, large vehicles and small cars drum brake, the difference may only have large pneumatic AIDS, and small cars to assist with vacuum brake. That's why big trucks still use drum brakes. Faults 1. Drum brake drum in the heat after the diameter will increase, and cause the brake pedal under the stroke increased, prone to brake reaction is not as expected. Therefore, when driving a vehicle with drum brakes, we should try to avoid continuous brake pad due to high temperature and thermal degradation phenomenon. 2. Brake system response is slower, brake pedal force is less easy to control, not conducive to high-frequency braking action. 3. Complex components, brake clearance must be adjusted, making maintenance difficult. It is well known that the advantages of disc brakes is sensitive, and it's good heat dissipation, braking force is more uniform and also good-looking, so before the use of high-end vehicles disc brakes. The cost of disc brakes is getting lower and lower nowadays, and disc brakes are becoming more and more common in household cars. Because the general weight of the family car is not high, for the sensitive requirements are greater than the force requirements, so disc brake more for the family car. The advantage of the drum brake is the strength, for the truck, the weight of the car itself is much higher than the family car, coupled with the dragging of the goods its weight is very considerable. And the basic brake is "stand" , so to put the heavy truck brake, the brake force requirements for a lot more than the sensitive requirements, so the truck use drum brake. But because the truck brake is not sensitive enough, so the family car owners on the road to see a large truck and it must not go to rush the road, especially some dangerous overtaking action do not do, is likely to cause rear-end collision. Although it is entirely responsible for the rear-end collision of the truck, how can the small body of a family car withstand a collision by such a large truck? It may not only be our car that will be damaged by then, but the defect of the brake drum is that there is a problem with the heat dissipation, it's easy to get heat exhaustion, which is why the brakes are starting to fade out of the family car business. Even if it is on the truck, there are often accidents such as tire fire on the highway, because the brake is too tired, because the heat is too high, but the strength of the drum brake still makes it irreplaceable in the truck.
