What is the working principle of disc brakes?

[DiKiara]

Here is an introduction to the working principle of disc brakes: 1. During braking, hydraulic fluid is pressed into the inner and outer wheel cylinders, and their pistons press the two brake pads against the brake disc under hydraulic pressure, generating frictional torque to achieve braking. At this time, the edge of the rectangular rubber sealing ring in the wheel cylinder groove undergoes slight elastic deformation due to the frictional force of the piston. When the brake is released, the piston and brake pads return to their original positions relying on the elasticity of the sealing ring and the spring. Since the deformation of the rectangular sealing ring edge is minimal, the gap between the friction pad and the disc is only about 0.1mm on each side when not braking, which is sufficient to ensure the release of the brake. 2. When the brake disc expands due to heat, its thickness changes only slightly, so the 'dragging' phenomenon will not occur. The rectangular rubber sealing ring not only serves as a seal but also helps the piston return and automatically adjusts the gap. If the wear on the friction pad of the brake pad increases the gap with the disc, the piston can continue to move after the sealing ring deformation reaches its limit during braking until the friction pad presses firmly against the brake disc.