There are disc brakes, drum brakes and air brakes, and many old cars are bulging at the front and back. Many cars have front and rear brakes. Because the disc brake has better heat dissipation than the drum brake, it is not easy to produce thermal recession in the high-speed braking state, so its high-speed braking effect is better. But at low speed, the braking is cold, and the braking effect is not as good as that of drum braking. The price is more expensive than drum brakes. Therefore, many medium and high-end vehicles use full-face brakes, ordinary vehicles use front disc and rear drum, while trucks and buses with relatively low braking force still use drum brakes.
Drum brakes are sealed and shaped like drums, and there are many brake pots in China. It spins when you drive. Two arc-shaped or semicircular brake shoes are fixed inside the drum brake. When braking, the two brake shoes extend out under the action of the brake wheel cylinder, and the supported brake shoes friction with the inner wall of the brake drum to slow down or stop.
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Advantages of disc brake:
1, the disc brake has better heat dissipation than the drum brake, and continuous braking will not cause brake retrogression and brake failure.
2. The change of brake disc size after heating does not increase the stroke of stepping on the brake pedal.
3. The disc brake system responds quickly and can perform high-frequency braking action to meet the requirements of ABS system.
4. Disc brake has no automatic tightening function of drum brake, so the braking force of left and right wheels is relatively uniform.
5. Because the brake disc is well drained, the situation of poor braking caused by water or sediment can be reduced.
6. Compared with the drum brake, the disc brake is simple in structure and easy to maintain.