Disc brake is a device installed and used on the disc axle (disc brake axle). It has the advantages of fast heat dissipation, rapid braking response, light weight, simple structure, excellent performance of anti heat attenuation and water attenuation, and stable braking effect. Therefore, it is widely used in all kinds of small passenger cars.

With the continuous development of vehicle technology and the continuous improvement of relevant laws and regulations, at present, some commercial vehicles, such as three-axis fence, three-axis warehouse grid, hazardous chemicals transport vehicle and other models, and some high-end and new commercial vehicle models also gradually began to use disc brake.

The rotating element in the friction pair of the disc brake is a metal disc working on the end face, which is commonly known as the brake disc. The brake disc is tightened from both sides through the friction element to generate friction and form the braking effect.

Common disc brakes can be divided into two types: caliper disc brake and full disc brake.

1、 Nipper disc

At present, the caliper disc brake has a wide range of applications in most cars and light trucks. It has the characteristics of strong heat dissipation efficiency and good thermal stability. Its rotating element is the brake disc, and its fixed element is the brake caliper. According to the movement mode of the brake caliper, it can be divided into fixed caliper disc brake and floating caliper disc brake.

1. Fixed caliper disc brake

The fixed caliper brake caliper is fixed on the axle housing and cannot rotate or move. Two pistons are installed in the brake caliper on both sides of the brake disc. When the driver presses the brake pedal, the hydraulic pressure of the brake wheel cylinder rises, the pistons are pushed out slightly, and the brake pad tightens the brake disc to produce braking. In short, the working principle of the fixed caliper disc brake is similar to that of the self driving brake.

2. Floating caliper disc brake

The brake caliper of the floating caliper disc brake is connected with the axle housing through the guide pin, which can realize the axial sliding relative to the brake disc. Only the actuating device is set on the inner side of the brake disc, and the brake pad on the outer side is attached to the caliper body.

When the driver brakes, under the action of hydraulic pressure, the piston in the brake wheel cylinder and the brake pad on it move to the left and press on the brake disc, so the brake disc gives the piston a right reaction force, making the piston and the brake caliper move to the right along the axis of the guide pin until the brake pad outside the brake disc is also pressed on the brake disc. At this time, the brake pads on both sides of the brake disc are pressed on the brake disc, and the rotating brake disc is clamped to produce braking.

2、 Full disk type

The fixed element and rotating element of the friction pair of the full disc brake are disc-shaped, which are called fixed disc and rotating disc respectively. During the braking process, all working surfaces can be in friction contact at the same time, and the structural principle is similar to that of the friction clutch.

Because this kind of brake uses disc instead of the original brake pad, the friction area is large during braking, so the braking force provided is relatively large, which is more suitable for heavy-duty trucks. On the other hand, the large friction contact area also leads to the generation of a large amount of heat energy during the braking process, which is not easy to be discharged. Under long-term continuous braking, it is easy to cause the brake disc to be heated and deformed, affecting driving safety. At the same time, the service life of the friction plate will also be affected, and it needs to be replaced frequently.