Warming up the brakes can be a tricky problem for truck drivers who often take long downhill stretches. At present, the commonly used methods mainly include water spray, engine auxiliary braking and hydraulic retarder.
However, the sprinkler system itself has many drawbacks, especially in winter, it is extremely dangerous, so in many areas, sprinkler is prohibited in winter; and the hydraulic retarder is currently not very popular due to the price problem; There are certain requirements for operation, and many truck drivers do not master this skill very well.
● Circumferential disc brake
The first is the circumferential disc brake. It first appeared at CIMC Huajun 2019 Business Annual Conference. Although the name is "Circumferential Disc Brake", its structural design is similar to that of drum brakes:
Traditional drum brakes generally use the internal brake shoes to rub the brake drum to decelerate, while this kind of brake is arranged with brake shoes on both the inside and outside of the "brake drum". , hug the outside inward.
Because it puts half of the brake shoes on the outside and can directly contact the air, its heat dissipation effect is better than that of traditional drum brakes. In addition, an air guide is added in the middle of the brake. As the wheel speed increases, the air guide will blow air into the brake to help the brake dissipate heat.
● Cast aluminum ring with cooling ribs
The second is cast aluminum ring with cooling ribs. We all know that aluminum rims are not only lighter than steel rims because of their material, but also because of their excellent thermal conductivity, they can also dissipate the temperature generated by the tire friction faster.
The cooling ribs, as the name suggests, can be set on the surface of the item or on the surrounding sheet-like objects. When viewed along the height direction, it can show a straight line or a curve. It is a parallel layout. Its function is similar to an engine fan, except that one is actively rotating. One is passive rotation.
So what does combining the two of them do? Because of its aluminum alloy material, it has the effect of rapid heat dissipation. The cooling fins are rotated by the rotation of the rim to achieve the effect of forced ventilation. In addition, the rim is also designed with air vents, and the cast aluminum ring with cooling ribs can force the cooling of the brake pads and improve the braking effect.
Therefore, in theory, the braking effect of the cast aluminum ring with cooling ribs is still very good. However, such rims are rarely equipped in vehicles on the actual road. In my opinion, there are three main reasons for this:
First, in the face of continuous long downhill, the heat dissipation effect may not be as good as imagined;
Second, the price of aluminum alloy rims is not low, and this special shape will undoubtedly further increase its production cost, and the final price will not be very close to the people.
Therefore, this configuration is not widely popular at present.
● Water-cooled circulating axle
The third type is the water-cooled circulating axle. This configuration first appeared at the Liangshan Special Vehicle Auto Show in 2017. It is a product launched by a company called Jiangling Huayue. It is mainly composed of a water storage tank, a radiator and several pipes.
So how does it work? From a structural point of view, it should be that the water in the water tank is driven by an electric water pump, and the hubs at both ends are connected by a water pipe passing through the center of the shaft pipe. Then use the company's patented water separator to enter the interlayer of the two brake drums to cool the brake drums. Finally, the water cooling the brake drums returns to the radiator through the water separator for cooling, and then enters the water tank.
Card friends who may be familiar with the water spray device have already understood that if the water spray device is regarded as a non-circulating system, then the water-cooled circulating axle is an internal circulation and reusable "water spray device". The water in the water tank enters the interlayer of the two brake drums through the pipe and the water divider respectively, and the cooled water returns to the original way, so that the cooling can be repeated without worrying about the water spilling on the ground.
● Conclusion
At present, the most effective and safest way to face long downhills is still hydraulic retarder and engine-assisted braking. Although the above three products have various problems, the spirit of continuous exploration in order to solve the problem is personally considered very worthy of recognition.