The brakes currently have disc brakes, drum brakes and air brakes. Many older cars have front and rear drums. Many cars now have disc brakes before and after. Because the disc brake has better heat dissipation than the drum brake, it is not easy to produce thermal recession under high-speed braking, so its high-speed braking effect is good. But at low-speed cold brakes, the braking effect is not as good as the drum brake. The price is more expensive than the drum brake. So now many mid-to-high-end cars use full disc brakes, while ordinary cars use front disc and rear drums, while trucks and buses with relatively low speeds and high braking force still use drum brakes.

The brake disc of the disc brake is a round plate, and it also rotates when the car is moving. The brake caliper is used to clamp the brake disc with two pieces to generate braking force. Its relatively rotating brake disc is fixed. When applying the brakes, it clamps the brake disc to slow down or stop.

The drum brake is sealed and shaped like a drum. It is also called a brake pot in China. It rotates when driving. There are two curved or semicircular brake shoes fixed inside the drum brake. When stepping on the brake, the two brake shoes are stretched out under the action of the brake wheel cylinder, supporting the brake shoes and rubbing against the inner wall of the brake drum to slow down or stop.

Material requirements

The material of the brake disc is the gray cast iron 250 standard of our country, referred to as HT250, which is equivalent to the American G3000 standard. The requirements of the three main elements of chemical composition are: C: 3.1~ 3.4 Si: 1.9~ 2.3 Mn: 0.6~ 0.9. Mechanical performance requirements: tensile strength > 21on/mm2, hardness requirements between: 187~ 241.