Which is better, drum brake or disc brake? Since the implementation of GB7258, the discussion on this issue seems to have been uninterrupted. Many car owners questioned whether it was necessary to force all three-axle railings and three-axle grid semi-trailers to install disc axles.

Objectively speaking, among the number of commercial vehicles in China, three-axle fence and three-axle warehouse grid semi-trailer account for a relatively high proportion, and the goods they transport are generally low value-added products. Therefore, many car owners transport according to the upper limit of load, and there are relatively many cases of overload. In addition, the selling price of such vehicles is low and the technical safety configuration is relatively low. Forcing these vehicles to use disc brake and airbag suspension can reduce overloading and improve the safety factor to a certain extent.

Then why is it mandatory to install a disc axle?

As we all know, the braking force of disc axle is smaller than that of drum axle. Although the braking principle of the disc axle is similar to that of the drum axle, which generates friction through the brake pads to slow down the vehicle, the disc brake clamps the brake disc through the caliper to make the brake pads inside the caliper rub with the brake disc; Drum brake is different. It lifts the brake pad to grab the inner wall of the brake drum to produce friction. The friction area is larger, the friction is larger, and the braking force is naturally larger.

A car may mainly ask: since the drum axle has greater braking force, why can't you see its shadow on high-end cars? In fact, it is also because of the structure of the drum axle, which gives it the advantage of large braking force, but also produces some congenital deficiencies.

For example, the heat dissipation is too poor. Brake suck and brake drum friction brake, will generate a lot of heat, this time because of 360 degrees without dead angle package drum, causing heat dissipation.

If the brake drum and brake pad are at high temperature for a long time, the braking effect is easy to be affected. There are two main reasons: the thermal attenuation of the hardness and other material properties of the brake drum and brake pad at high temperature affects the friction braking; Secondly, under the principle of thermal expansion and cold contraction, the distance between the brake drum and the brake pad increases, resulting in insufficient fit between the brake pad and the brake drum during braking. In addition, overheating of the brake drum can easily lead to smoke and even fire, which is very unfavorable to driving safety.

Therefore, drum brake owners will basically be equipped with water spraying device to cool the brake drum through water spraying.

However, there are also problems in watering and cooling. After all, the brake drum is like a washbasin, which is most likely to accumulate water. Once it accidentally enters the water, it will exist in the brake drum, which will affect the braking effect. It may also lead to tire locking. Even if it is lucky that there are no serious consequences, the brake drum is easy to rust if it is not cleaned for a long time, The braking system is basically useless. This is also another disadvantage of drum brake. In case of rainstorm and puddle, you need to be extra cautious.

For the northern region, the temperature is low in winter. If the vehicle uses the water spraying device, the water will easily freeze on the road and affect traffic safety. Therefore, many road sections are not allowed to use the water spraying device in winter.

In addition to poor heat dissipation and easy ponding, drum brake also has a major disadvantage, which also starts with its large braking force. For vehicles with drum axle, the tires need to be adjusted frequently because they can not be adjusted automatically. If they are not adjusted for a long time, it is easy to lead to uneven distribution of braking force of each tire. Some excessively worn brake pads due to adjustment problems will lead to inconsistent braking force. Once there is an emergency brake, it is easy to lead to sideslip, deviation and even out of control, which is very dangerous.

In addition, the braking reaction time of drum brake is slower than that of disc brake. When the owner steps on the brake, the drum brake needs to go through several mechanical transmission devices to push the brake pads for braking, but the disc brake can immediately drive the brake pads to produce friction braking. It is also because the braking response of drum brake is slow. Many auxiliary braking devices such as ABS and EBS can not give full play to the maximum effect, or even backfire.

If the disc brake is replaced, there will be no such trouble. The heat dissipation performance is far ahead. After all, a large metal disc is exposed outside. If the speed is high, it will be cooled naturally every minute, and there is no ponding. It is impossible to store water in a metal disc placed vertically. After water is involved, the performance can be restored immediately by braking once or twice.

It is criticized that the braking force of disc brake is small, especially for vehicles that often transport heavy goods or often run on mountain roads, can the installation of disc axle smoothly realize braking?

In fact, it is possible, provided that it is equipped with auxiliary braking devices, such as the hydraulic retarder of the main vehicle. The hydraulic retarder has the advantages of light weight, large braking torque, soft, stable braking and no impact. It can also brake with high power for a long time without heat recession. It can make up for the lack of braking force of disc brake, greatly reduce the wear of disc brake and ensure driving safety. According to relevant sources, within the legal nuclear load limit, vehicles equipped with hydraulic retarder encounter continuous long downhill. Even if they do not step on the brake, they can ensure the stable driving speed of the vehicle, but it is very dangerous if they are overloaded.

As mentioned above, ABS and EBS can also be used in combination with disc axle, which can prevent wheel locking in case of emergency braking and make the vehicle stop smoothly within the shortest braking distance. This is also the reason why relevant departments implement disc axle.

Of course, the effect of the disc axle depends on whether the quality and performance of the axle purchased by the car owner meet the standard. If it is some shoddy products, in case of heavy load or bumpy road conditions, the axle may not withstand the pressure, have problems or even break. Darong disc axle is developed and manufactured by Darong group, the first axle enterprise to mass produce integrated axle in Liangshan special vehicle production base. The axle body and axle head are polished on the same high-strength alloy steel pipe, which is superior to welded axle head in heavy load performance. There are 15 production processes, such as 1300 ℃ hot rotary rolling, 865 ℃ medium frequency quenching, 480 ℃ heat preservation treatment, precision grinding of CNC machine tools, etc, In strict compliance with industry standards, combined with online + offline dual quality inspection, the product quality is strict and up to standard, fully meeting the use needs of users.