D1399 Brake Pads

What does the friction coefficient of the brake pads mean?

The coefficient of friction refers to the ratio of the friction between the two surfaces and the vertical force acting on one surface, that is, the ratio of the friction between the brake pad and the brake disc and the force acting on the brake pad.

The coefficient of friction is a value that varies with temperature or other conditions. In the domestic auto parts market, the state has issued a national standard for brake pads, namely GB5763-2008, which sets a certain range for the friction coefficient of brake pads.

The coefficient of friction refers to the ratio of the friction between the two surfaces and the vertical force acting on one surface, that is, the ratio of the friction between the brake pad and the brake disc and the force acting on the brake pad. That is: μ = f / N. Where: μ is the coefficient of friction, no unit; f is the friction, unit: cattle (N); N is the pressure, unit: cattle (N).

The national standard defines a range of friction coefficients at different temperatures, such as a friction coefficient range of 0.25-0.70 at 200 °C. The national standard stipulates that in the six temperature points of 100 ° C to 350 ° C, as long as the friction coefficient of one of the temperature points is lower than or higher than the range specified by the national standard of the temperature point, it is a substandard product.

Brake structure

The disc brakes of automobiles are also called disc brakes. They are controlled by hydraulic pressure. The main components are brake discs, sub-pumps, brake calipers and oil pipes. The braking performance of a car is one of the main performances of a car. It is related to the safety of vehicles and personnel. It is an important guarantee for safe driving of a car. How does the brake of the car work?

The brake disc of the car is made of alloy steel and fixed on the wheel, rotating with the wheel. The sub-pump is fixed on the bottom plate of the brake and is fixed. The two brake pads on the brake caliper are respectively mounted on the two sides of the brake disc, and the piston of the sub-pump is hydraulically conveyed by the oil pipe to push the brake pad pressure. Friction braking occurs to the brake disc as if the rotating plate is clamped with pliers to generate friction, thereby stopping the running vehicle. The institutional nature of a car depends not only on the performance of the brake system, but also on the driving performance of the car, the mechanical properties of the tire, the attachment conditions of the road, and the ergonomic properties associated with the brake operation.

The reason why there is no strength when braking

Some car owners feel that the brake pedal is not pressed when driving, which is what we usually call soft brakes. The soft and hard brake can be understood as the relationship between the strength of the brake pedal and the actual braking speed of the vehicle. The soft brake is the strength of the pedal and the slow deceleration. The brake is hard and the speed is slow. For vehicles with normal braking system, the soft and hard brakes do not mean the performance of the brakes, but the adjustment of the brakes is different.

The softness of the car's braking force is that the braking force is easier to control when driving at low and medium speeds, especially in the case of traffic jams. However, the disadvantage is that when a large braking force is required, the pedal travels longer and requires more force. The advantage of the hard brake is that the brake response is more sensitive and the braking force responds more quickly. However, the inferior quality is that it is difficult to grasp the braking force when driving at low speed, it is easy to nod and generate unnecessary emergency brakes, and even cause rear vehicle rear-end collision.