With the prevalence of lightweight trend in the freight industry, disc brake bridges are increasingly favored by car owners. The disc brake axle has no 360 degree wrapped brake drum, and the brake transmission components have also been optimized, so it has obvious advantages in terms of weight.

After the introduction of GB7258-2017, it is required that the three axle breast board and three axle cage semi-trailer must be equipped with disc brake bridge and air suspension, otherwise the vehicle registration will be affected. However, we all know that the braking force of disc brake axle is not as good as that of drum brake axle. Will it affect the braking effect when it is used on semi-trailer? Is it reliable for disc brake axle to be used as the rear axle of semi-trailer?

Indeed, compared with the brake drum and brake pad of drum brake axle, the brake friction area of disc brake axle is indeed smaller, which leads to the brake force output of disc brake axle is smaller than that of drum brake axle under the same load. However, this "less than" is relatively speaking. Although the braking force of the disc brake bridge is small, it is still more than enough to meet the braking demand of standard load vehicles.

In addition, since the disc brake axle cancels the complicated brake transmission mechanism of the drum axle, when the car owner steps on the brake pedal, the brake disc can be directly clamped by the caliper driven by the wheel cylinder, which means that the reaction speed of the disc brake is faster than that of the drum axle. This reaction speed can be used together with ABS or EBS system to maximize the advantages of these auxiliary devices.

To return to the problem of disc brake axle braking force, if the owner is really worried, it can be used with the hydraulic retarder, which is also the best scheme for installing disc brake axle on semi-trailer. The hydraulic retarder is light in weight, large in braking torque, and soft and stable in braking output. It can also avoid heat recession under long-term high-power braking. It can not only greatly compensate for the lack of braking force of the disc brake axle, but also reduce the wear of brake components and reduce the cost of comprehensive vehicles. If the ABS or EBS system is combined on this basis, the drum brake axle can be reversed to allow the trailer to stop smoothly in the shortest braking distance.

In addition, the thermal attenuation resistance of disc brake axle is better than that of drum axle. According to the comparison of experimental data, when the temperature of drum brake reaches more than 300 degrees, the friction coefficient decreases by 40% - 50%. In contrast, when the temperature of disc brake bridge rises from 100 degrees to 400 degrees, the friction coefficient hardly changes.

After the vehicle wades into the water, the disc brake axle only needs 1-2 times of braking to recover its performance, while the drum brake axle needs more than ten consecutive times of braking to recover its performance. The brake drum is also easy to store water, which affects the braking effect, and can easily lead to wheel lock, brake rust and other problems.

To sum up, the disc brake axle can be used on the rear axle of the semi-trailer. However, the actual application is much more complicated than the theory, and more factors need to be considered. Therefore, whether the disc brake axle can provide reliable performance guarantee for the semi-trailer depends on the actual situation.

The first is the quality of the disc brake bridge. If the quality of the product itself is not up to the standard or even poorly manufactured, it will not only fail to provide guarantee for the vehicle, but even endanger the driving safety in turn. It is recommended that car owners not only choose cheap maps, but also try to choose products that have been in the market for a long time and have been fully tested by the market;

The second is to use the right working conditions, "A's honey and B's arsenic". The best product is the one that suits your working conditions. Generally speaking, in addition to the three-axis fence and bin fence clearly specified in the regulations, the disc brake bridge can be selected for precision instrument transportation, fragile goods transportation, hazardous chemicals transportation, Lvtong transportation, valuables transportation, and other transportation conditions dominated by standard load. As for those who often run heavy loads and have low requirements for cargo damage, it is recommended to use drum brake bridge;

Finally, it is used in compliance with the regulations. "The public mind is not enough, the snake swallows the elephant". The selection of the axle should match the tonnage. If the vehicle owner often transports illegally, overloads and exceeds the limit, let alone the disc brake bridge. Even the American drum brake bridge, which is famous for its high bearing capacity, may be difficult to guarantee its performance under long-term overload use. Therefore, the book is divided into different types of transportation, and you can sail a ship for ten thousand years only if you are careful.