The brake disc, in simple terms, is a round disc that also rotates as the car travels. The brake caliper clamps the brake disc to generate braking force. When the brake caliper is pressed, it clamps the brake disc to slow down or stop. Brake discs work well and are easier to maintain than drum brakes.
There are disc brakes, drum brakes, and air brakes. Many older cars have front wheels and rear drums. Many of the car’s front and rear are disc brakes. Because the disc brake dissipates heat better than the drum brake, under high-speed braking conditions, it is not easy to cause heat decay, so its high-speed braking effect is good. However, the braking effect is not as good as that of the drum brake at the low-speed cold brake. The price is more expensive than the drum brake. Therefore, many medium and high-end cars use full disc brakes, while ordinary cars use front discs and rear drums, while relatively low speed trucks and buses that require large braking forces still use drum brakes.
The drum brake is sealed and shaped like a drum. It turns while driving. Two curved or semi-circular brake shoes are fixed inside the drum brake. When the brake pedal is pressed, the two brake shoes are expanded under the action of the brake wheel cylinder, and the brake shoes are supported to rub against the inner wall of the brake drum to slow down or stop.
The brake disc is divided into a solid brake disc and a ventilation disc according to the structure. The physical brake disc is a metal disc used for braking, and has no special structure. There are two types of ventilated discs, namely, scribing discs and perforated discs. The two methods of processing are to improve the cooling performance of the brake disc, reduce its thermal attenuation, and provide better braking capacity.
The brake discs are divided into carbon fiber ceramic brake discs and metal brake discs according to different materials. However, due to the excessively high manufacturing cost of carbon fiber ceramic brake discs and poor braking force at low temperatures, although they have excellent thermal attenuation characteristics, Not used by most vehicles. In order to increase the resistance to thermal decay, there are also manufacturers of carbon fiber treatment of metal brake discs to improve their ability in this regard, while avoiding the problem of poor low temperature performance of carbon fiber ceramic materials.
The brake discs must be used for braking, and the braking force comes from the brake calipers. Generally speaking, the general brake caliper is the part where the inner brake piston pump is fixed, and the outside is a caliper structure. The inner brake pads are fixed on the piston pump, and the outer brake pads are fixed on the outside of the caliper. The piston pushes the inner brake pads by the pressure from the brake tubing, and at the same time pulls the caliper through the reaction force to make the outer brake pads inward. Both are pressed towards the brake disc at the same time, and the braking force is generated by the friction between the brake disc and the inner and outer brake pads. In this process, the piston is driven by brake fluid, which is hydraulic oil. This is powered by the engine.
For hand braking, a cable mechanism is used to force the brake pads through a lever structure, so that they are pressed against the brake disc to generate braking force.
1. The disc brake has better heat dissipation performance than the drum brake, and it will not cause brake decay and brake failure when stepping on the brake continuously.
2. The size change of the brake disc after heating does not increase the stroke of the brake pedal.
3. The disc brake system responds quickly and can perform high-frequency braking actions, so it is more in line with the requirements of the ABS system.
4. The disc brake does not have the automatic braking effect of the drum brake, so the braking force of the left and right wheels is relatively average.
5. Because the brake disc has better drainage, it can reduce the situation of poor braking caused by water or sediment.
6. Compared with drum brakes, disc brakes have a simple structure and are easy to maintain.