The principle of drum braking is that in the brake drum […]
The principle of drum braking is that in the brake drum, hydraulic pressure is applied to the piston of the wheel cylinder, which pushes the curved brake shoe. The friction material of the bonding or rivet on the brake shoe presses the inside of the brake drum to slow the rotation of the brake drum and the axle to achieve the purpose of braking.
In fact, sometimes drum brakes are effective, but if you only use a brake drum to try to stop a high-speed car, you will find its limitations: it will thermally attenuate, the brake drum friction heat, causing expansion The brake shoe must be moved outward to contact the brake drum, which means that the brake pedal must be deeply depressed, and the gas generated by frictional friction of the material is trapped inside the brake shoe and the brake drum, which weakens the brake. ability. The first time the car is braked, it may stop quickly from high speed, but in the second brake, your luck is not necessarily so good.
One of the advantages of disc brakes is that the powder generated by friction between the friction lining and the brake disc is quickly ejected, and the heat is dissipated more quickly by the brake disc, resulting in better braking performance. Drum brakes are clearly relatively weak in this respect.
Due to the fast response of disc brakes and the ability to perform high-frequency brakes, many models use disc brakes in conjunction with ABS systems and systems such as VSC and TCS to meet the needs of such systems for fast operation. For these reasons, and in order to achieve maximum braking capacity, many cars are equipped with four-wheel disc brakes.