Drum brake principle:

Drum brakes have been used in the car for nearly a century, but because of its reliability and strong braking force, drum brakes are still deployed on many models (mostly on the rear wheels). Drum brake is by hydraulic will be installed in the brakes inside the brake pads to push out, so that the brake pads and wheel rotation with the friction inside the surface of the friction, and the effect of braking.

The brakes on the inside of the brakes are the position of the brake torque. In the case of obtaining the same braking torque, the diameter of the brake drum of the drum brake device may be much smaller than the brake disc of the disc brake. Therefore, large vehicles for heavy loads can only be equipped with drum brakes in a limited space for wheels to obtain a strong braking force.