Brake drums, also known as brake rotors, are a type of braking hub. The material for brake drums on the rear axle of electric three-wheeled vehicles is often cast iron, with strict requirements for processing precision.
Self-Braking Function: Drum brakes possess good self-braking action. As the brake pads expand outward, the wheel's rotation causes the expanding brake drum to twist slightly (of course, not enough to be easily noticeable). The greater the outward tension of the brake pads (braking force), the more pronounced the effect. Therefore, drum brakes are generally used in larger vehicles, not only due to their lower cost but also because the difference between drum brakes on large and small vehicles may only lie in the use of pneumatic assistance in larger vehicles, while vacuum assistance is employed in smaller vehicles to aid braking.