When will the drum brake change the disc brake into the national standard?

Recently, the police in Wuxi have already found the suspected vehicle of Wu Bin, the “most beautiful driver” in Suizhong. But many publics can not help but ask: why the brake hub can fall off from a moving truck? Is the braking/falling off hazard just a case? Or are trucks ubiquitous security risks?

Drum brakes have inherent safety problems

In some media reports, we have seen two possible reasons: the brake parts are not riveted or the brake parts are not overpowered. However, a traffic police told reporters: The brake failure is the main cause of truck accidents in recent years. As early as a few years ago, CCTV's “Walk into Science” section had recorded a special program called “Death Express”, which specifically reported the problem of truck brake failure on the slope. In a series of truck accidents conclusions, the reporter saw similar words many times: As trucks continuously use brakes, the grinding time of the brake shoe and the brake drum is increased, causing the temperature of the brake drum to increase and generate heat. The recession eventually led to brake failure.

Although drum brakes have led to frequent accidents in trucks, China has not imposed mandatory requirements on the selection of truck brakes. There is also a lack of relevant specifications for the hot recession hazard of drum braking performance.

It is understood that compared with the disc brakes commonly used in cars, drum brakes have a design structural defect in heat dissipation: under constant braking, the brake temperature may exceed 400 degrees, and the brake shoe will “burn” Smoke", the brake drum will "burn red". The reason for designing the structure is that it is difficult to dissipate heat on the friction surfaces of the brake shoe and the brake drum in a relatively “enclosed environment”. At this time, not only will the brake effect fade, resulting in brake failure. Moreover, once the water source such as water on the road is splashed by the tire to the brake drum in a high temperature state, it is easy to cause the brake cymbal to break, and in severe cases, the ruptured brake drum fragments are thrown directly.

The disc brake has good heat dissipation performance. The friction surfaces of the brake shoe and the brake disc are in direct contact with the air flow. The heat generated in the friction process can be directly ventilated and dissipated. In the case of continuous braking, the disc brake is 200 degrees lower than the friction pair temperature of the drum brake, which effectively ensures the stability and reliability of the truck during long-distance braking. In addition, in the disc brake system, the “caliper” structure of the brake shoe and the brake disc determines that the brake disc and the brake shoe cannot be broken into pieces to be thrown under any circumstances.

According to reports, in Europe and the United States and other developed countries, trucks, especially light trucks, have already withdrawn from the market. In China, except for a few high-end trucks that use more disc brakes, other trucks are still drum brakes.

Drum brakes directly lead to increased risk costs for users

Undoubtedly, due to the inherent safety hazards of drum brakes, an endless series of truck traffic accidents due to brake system problems have been created, bringing direct economic losses and indirect reputation losses to users.

A light truck user who has been in business for 20 years has given the reporter an account: Taking a light truck as an example, in the 1990s, if a traffic accident resulted in the death of a person, the user would have to pay an amount of 50,000 yuan in payment. In the current environment, if a traffic accident leads to the death of a person, the actual amount of compensation the user needs to pay is more than 500,000 yuan, and some even exceed 1 million yuan. The cost of traffic accidents has increased by 10 times. Traffic accidents involving casualties are often enough to make truck users lose their homes. The owner of the suspected vehicle, including Wu Bin, the “most beautiful driver” in the area, will also face direct or indirect compensation. If there is a traffic collision accident caused by a problem with the brake system, under the premise of no casualties and complete vehicle insurance, at least 7 days of operating time will be delayed to complete the accident handling and vehicle maintenance. The direct operating loss caused by the outage of vehicles exceeded 10,000 yuan, and the devaluation of vehicles exceeded 10,000 yuan. It is also very likely that the user will lose the source of goods due to the outage of the vehicle.

In the face of operational risk and cost control, users need more disc brakes to reduce accident rates and risk costs.

A veteran of a logistics company said: Before, because there is no more safe disc brake products available for selection, the company can only strictly require drivers to regulate driving in order to reduce hidden dangers.

At the end of May, the reporter participated in the interpretation of local standards for the operation of trucks in the central city of Beijing. At present, according to the leaders of the meeting, in order to improve the safety of trucks operating in cities, Beijing has established local standards for Beijing and will require the use of disc brakes for the front axles of the trucks.

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