1. Brake disc diameter
The diameter D of the brake disc should be as large as possible. At this time, the effective radius of the brake disc is increased, the clamping force of the brake caliper can be reduced, and the unit pressure and working temperature of the pad can be reduced. Due to the limitation of the rim diameter, the diameter of the brake disc is usually selected to be 70% to 79% of the rim diameter. Cars with a total weight greater than 2 tons should have an upper limit.
2. Thickness of brake disc
The thickness of the brake disc will affect the quality of the brake disc and the temperature rise during operation. In order to reduce the mass, the thickness of the brake disc should not be too large. In order to reduce the temperature, the thickness of the brake disc should not be too small. The brake disc can be made solid, or a ventilation channel can be cast in the middle of the brake disc for heat dissipation and ventilation. The thickness of ordinary solid brake disc is 10-20mm, and the thickness of ventilated brake disc is 20-50mm. The most commonly used brake disc is 20-30mm. When the brake brakes quickly at high speed, the brake disc will thermally deform and vibrate. In order to improve the heat dissipation performance of the friction surface of the brake disc, most brake discs are made of hollow ventilated brake discs, which can reduce the brake disc temperature by 20% to 30%.
3. Friction pad
Friction pad refers to the friction material that the clamping piston pushes against the brake disc. The friction pad is divided into a friction material and a base plate, and the two are directly press-fitted together.
Only the ratio of the outer diameter to the inner diameter of the friction pad and the recommended outer diameter and inner diameter of the friction pad is not greater than 1.5. If the ratio is too large, the outer edge of the pad and the inner circumferential speed during operation will be significantly different, the wear will be uneven, the contact area will be reduced, and the final braking torque will change greatly.
For the disc brake pad working area A, it is recommended to select the vehicle mass per unit area of the brake pad in the range of 1.6 to 3.5 (kg per square centimeter).
The brake disc is made of alloy steel, fixed on the wheel and rotates with the wheel. The auxiliary pump is fixed on the bottom plate of the brake, and the two friction plates on the caliper are installed on both sides of the brake disc. The piston of the auxiliary pump is driven by the hydraulic pressure transmitted by the oil pipe, pushing the friction plate to depress the brake. The disc brakes frictionally, holding the rotating plate like pliers and forcing it to stop.
