Drum brakes and disc brakes， Which brake is better?

We all know that there are drum brakes and disc brakes in the form of car brakes. Both of them generate huge friction between the friction lining, the brake drum, and the brake disc, which converts the kinetic energy of the vehicle into heat energy, so that the speed of the vehicle is reduced or stopped.

Both drum brakes and disc brakes have a long history of use. Everyone has mixed opinions on these two braking methods. Why disc brakes are more popular today? Let's discuss the reasons behind them.

Drum brake-large braking force and poor heat dissipation

Drum brakes are widely used in the field of commercial vehicles, and their application time is much earlier than that of disc brakes. Drum brakes are composed of a series of structures such as a brake cylinder, an adjusting arm, a brake camshaft, a brake shoe, and a drum type. When working, the brake transmission structure makes the brake shoes tightly press the brake pads on the inside of the brake drum, thereby generating braking force, and decelerating or even stopping the wheels according to the braking demand.

Although the structure of the drum brake is complex, the cost is low. The brake pads and brake drums of drum brakes are large in size, and the braking friction generated by them is also increased. For heavy-duty vehicles, the speed is not very high, so the durability of the brake shoes is also high, and the use of drum brakes can make the car park reliable and not automatically slide. In the case of obtaining the same braking torque, the diameter of the brake drum of the drum brake device is much smaller than that of the disc brake.

Although drum brakes are widely used, their shortcomings cannot be ignored. Due to the large volume of the brake pad and the brake drum of the drum brake, the contact surface between the two is large, and the heat dissipation is poor while generating a large braking force at a time. Since the entire brake pad is wrapped in the brake drum, the high temperature makes the braking stability insufficient, which may cause the brake to fail.

In addition, due to the wear of the brake shoes, the gap between the brake shoes needs to be corrected regularly, and it is even necessary to disassemble and clean up the garbage generated in the drum due to long-term use. Drum brakes have a complex structure, and any damage to any component can easily cause brake failure. Also, because of its complex structure, the transmission requires the transmission of various components step by step, resulting in slow response speed of the drum brake.

Disc brake-good heat dissipation and simple structure

Disc brakes are just the opposite of drum brakes. Disc brakes are mainly composed of brake cylinders, brake calipers, brake discs and brake pads. The structure is simpler than drum brakes. Because the disc brakes are exposed to the outside, and the working area of the brake disc is only 6%-12% of the brake disc area, so it has better heat dissipation.

The thermal expansion of the brake disc will not cause the brake pedal stroke loss like the thermal expansion of the brake drum, which simplifies the design of the automatic clearance adjustment device. Disc brake pads are more convenient to replace than drum brake pads, simplify the operation process of maintaining the brake, and greatly reduce the difficulty of later maintenance.

Because there are fewer parts and the gap between the brake disc and the brake pad is very small, the braking response speed is much faster. The superior heat dissipation makes it less likely to cause thermal degradation under high-frequency braking actions. This feature is more in line with the needs of the ABS system. Therefore, the disc brake can make the ABS\EBS and other brake assist systems more effective. Adequately, the advantages of disc brakes with brake assist systems are gradually becoming prominent.

Disc brakes are more expensive than drum brakes. In some special environments with more sand and gravel, the disc brake discs are extremely easy to be damaged. Compared with the brake disc of the same size, the disc braking force is weaker than the drum type, and the brake pads are more worn and replaced more frequently. Disc brakes need to be used in conjunction with other auxiliary brakes to exert greater braking efficiency. Compared with heavy-duty trucks that require large braking torque, drum brakes have a much better braking effect than disc brakes.

Through comparison, we will find that the manufacturing cost of drum brakes is low, and its large braking force is more suitable for low-speed and heavy-duty vehicles. As for the disc brake, its simple structure facilitates later maintenance and reduces the weight of the brake itself. The excellent heat dissipation prevents the continuous braking of the vehicle from causing brake failure due to thermal degradation, which improves the safety of the entire vehicle.