How to choose disc brake drum brake? See what the old driver says

History of disc brake and drum brake

Since the German Karbenz invented the use of single-stroke internal combustion engine cars, the car speed finally barely reached 19 kilometers per hour, and in the future time to break through, at the same time the role of the braking system began to gradually reveal.

At the beginning, the British invented the brake mode of hair stained asphalt with the brake drum, but with the increase of speed, this original brake method has a general effect, and it is easy to fail. So in 1900, German engineer Wilhelm Maybach invented a drum brake with stronger trailer axle braking force. Around 1902, British engineer Frederick William Lanchester invented a more durable disc brake.

Although the drum brake and the disc brake appeared at a similar time, their respective development processes are very different. At the beginning, because of the material problem of the disc brake, the drum brake has an absolute advantage and is widely used in all kinds of models.

With the development of materials science, in 1933 the United States Chrysler Company was officially equipped with four-wheel disc brake, which also marks the beginning of the disc brake counterattack, until now most of the passenger cars on the market, motorcycles, bicycles are used with disc brakes.

However, this trend is not obvious in the field of commercial vehicles, because the quality of commercial vehicles is generally higher, and its own kinetic energy is much larger than that of passenger cars, so the drum brake with larger braking force is more popular. Until recent years, the performance of the disc brake has been further improved, but also has better heat dissipation capacity, so now more and more heavy trucks have begun to use the disc brake.

In particular, the implementation of GB7258-2017 "Technical Conditions for the safety of Motor Vehicle Operation" has added new requirements that all wheels of dangerous goods transport semi-trailers, three-axis rail-plate and warehouse grid semi-trailers should be equipped with disc brakes, and the drum dispute has entered a climax.

With a plate and a drum? Car owners have different opinions

Does the truck have a disc brake or a drum brake? The owners have different opinions, and the views of the two brakes are also very different, below we will take a look at the comments of the owners.

From the above, it is not difficult to see that the owners who now support the disc brake and support the drum brake have their own views, but in general, the supporters of the drum brake are still more, they mainly feel that the brake ability of the disc brake is still reliable, and durable. However, the disc brake master attacked the thermal attenuation effect of the drum brake, and the safety is not as good as the disc brake.

Then let's take a look at the structure of the disc brake and the drum brake.

Drum brake: large braking force but poor heat dissipation

The working principle of drum brake is very simple, it is composed of brake bottom plate, brake pump, brake shoe and other related connecting rod, spring, pin, brake drum. By hydraulically pushing the piston, the brake shoes on both sides are close to the inner wall of the wheel, thus achieving the braking effect.

As an old friend of many owners, the drum brake structure is not easy to damage, the quality is solid, the cost is low, and the most important is that the braking force is also very large, and it is very friendly for heavy duty users.

But also because of the closed structure, the heat dissipation of the drum brake is relatively poor, in the process of using the brake, the brake pads will be violently friction with the brake drum, and the heat generated is difficult to be eliminated in time, once the time is too long, trailer axle it will lead to the brake overheating performance attenuation, and even burn the brake shoes to lose braking power.

In order to solve this problem, many owners choose to install a sprinkler on the car to cool the drum brake when facing a long downhill, so as to avoid the phenomenon of thermal decay. But in this case, it is necessary to frequently add water to the tank, which is costly and troublesome, and it will be banned in the northern winter.

Disc brake: not afraid of thermal attenuation, but the cost is more expensive

Disc brake is mainly composed of brake pump, brake calipers, brake pads and brake discs and other components, the overall structure is simple, fewer parts, brake response speed will be very fast. The working principle of the disc brake and the drum brake is actually similar, but the difference is that it is through the hydraulic pump to push the brake caliper to clamp the brake pad to produce friction, so as to achieve the braking effect.

Therefore, from the structural point of view, the disc brake will be open, so the heat generated by the friction between the caliper and the brake pad will be easily released during the braking process. Even if subjected to continuous high-speed braking, braking performance will not occur too much thermal attenuation. And because of the open structure of the disc brake, it will be more convenient for maintenance. It is also necessary to mention here that the disc brake trailer axle can not be sprayed, if the water will cause the brake pad to crack.

However, compared with the drum brake, the cost of the disc brake is more expensive, and under the same size brake disc, the braking force of the disc brake is smaller than the drum brake. Therefore, the disc brake will be used with ABS and hydraulic retarder auxiliary brakes. Although some owners ridicule increased costs, but the disc brake and auxiliary brake good phase also provides it with excellent plasticity.