Explanation of Automotive Braking Systems

　　A series of specialized devices that can forcibly reduce the speed of a vehicle. The braking system is mainly composed of four parts: energy supply device, control device, transmission device, and brake. The main function of the braking system is to reduce or stop the speed of a moving vehicle, maintain a stable speed of a vehicle traveling downhill, and keep a stopped vehicle stationary.

　　Braking systems can be classified as follows:

　　⑴ According to the function of the braking system, it can be divided into service braking system, parking braking system, emergency braking system, and auxiliary braking system. Among the above braking systems, the service braking system and the parking braking system are mandatory for every vehicle.

　　⑵ According to the braking control energy source, braking systems can be divided into manual braking systems, power braking systems, and servo braking systems. A braking system that uses the driver's body as the sole braking energy source is called a manual braking system; a system that brakes entirely by using pneumatic or hydraulic potential energy converted from engine power is called a power braking system; a braking system that uses both manual and engine power for braking is called a servo braking system or power-assisted braking system.

　　⑶ According to the transmission method of braking energy, braking systems can be divided into mechanical, hydraulic, pneumatic, and electromagnetic types. A braking system that uses two or more energy transmission methods is called a combined braking system.

　　General working principle of the braking system

　　The general working principle of the braking system is to use friction between a non-rotating component connected to the vehicle body (or frame) and a rotating component connected to the wheel (or drive shaft) to prevent the wheel from rotating or tending to rotate. A metal brake drum with an inner circular surface as the working surface is fixed to the wheel hub and rotates with the wheel. On the stationary brake backing plate, there are two support pins supporting the lower ends of two arc-shaped brake shoes. The outer surface of the brake shoe is fitted with friction pads. A hydraulic brake wheel cylinder is also installed on the brake backing plate, connected to the hydraulic brake master cylinder installed on the frame via an oil pipe 5. The piston 3 in the master cylinder can be operated by the driver through the brake pedal mechanism. When the driver steps on the brake pedal, compressing the brake fluid, the wheel cylinder piston, under the action of hydraulic pressure, presses the brake shoe against the brake drum, causing the brake drum to reduce its rotational speed or remain stationary.