Drum braking is also called block braking, which is achieved by pressing the brake block on the brake wheel. Drum brake is an early design of the brake system, the design of the brake drum has been used in carriages since 1902, until around 1920 began to be widely used in the automobile industry. Now the mainstream of the drum brake is the internal tensioning type, its brake block (brake shoe) is located inside the brake wheel, and the brake block opens outward when braking, rubbing the inside of the brake wheel to achieve the purpose of braking.
Compared with disc brakes, the braking efficiency and heat dissipation of drum brakes are much worse, the braking force stability of drum brakes is poor, and the braking force changes greatly on different roads, which is not easy to control. Due to the poor heat dissipation performance, a lot of heat will gather during the braking process. Under the influence of high temperature, the brake block and drum are prone to complex deformation, which is easy to produce brake decay and vibration, resulting in the decrease of braking efficiency. In addition, after the drum brake is used for a period of time, the gap of the brake shoes should be adjusted regularly, and even the entire brake drum should be removed to clean up the accumulated brake powder. Of course, drum brakes are not all bad, it is cheap, and in line with traditional design.
