Air Supply System: The core component is the air compressor: It is the air source for the entire vehicle's braking system, responsible for compressing air into high-pressure gas. Taking the Steyr 6x4 truck as an example, its air compressor is a single-cylinder hybrid-cooled type, with the cylinder block air-cooled and the cylinder head water-cooled through the engine cooling system. This compressor is fixed to a bracket on the left side of the front of the engine, and the drive gear is connected to the crankshaft with a high-torque self-locking connection. It is cantilevered in the timing gear chamber and driven by the engine crankshaft through an intermediate gear, fuel injection pump gear, and air compressor drive shaft. Its structure mainly includes the air compressor housing, piston, crankshaft, one-way valve, and other components.
Auxiliary components include the air reservoir: Used to store compressed air, ensuring a continuous air supply to the braking system when the air compressor is not working. The air reservoir is usually divided into multiple chambers, storing air at different pressures to meet the needs of different braking circuits.
Control Devices: Brake Pedal: The driver controls the braking system by pressing the brake pedal. The brake pedal is connected to the brake valve. When the pedal is depressed, it pushes the piston of the brake valve, opening the passage for compressed air.
Brake Valve: The core control component of the pneumatic braking system, used to control the flow direction and pressure of compressed air. Brake valves are typically dual-chamber type, controlling the braking circuits of the front and rear axles separately. When the brake pedal is depressed, the brake valve adjusts the pressure of the compressed air entering the brakes according to the pedal travel and pressure, thereby regulating the braking torque.
Relay Valve: Used to accelerate the response speed of the brakes, especially in long-wheelbase or multi-axle vehicles. Installed near the brakes, the relay valve reduces braking delay and improves braking efficiency by shortening the transmission distance of compressed air.
Safety Valve: Used to protect the braking system from damage caused by excessive pressure. When the system pressure exceeds the safety valve's set value, the safety valve automatically opens, releasing excess compressed air to ensure system safety.
Pressure Regulator: Used to regulate and stabilize the pressure of the braking system, ensuring that the brakes achieve a stable braking torque under different operating conditions.
Transmission System
Brake Chamber: This component converts compressed air pressure into mechanical thrust. The brake chamber typically consists of a diaphragm or piston. When compressed air enters the brake chamber, the diaphragm or piston moves outward, pushing the brake adjusting arm to rotate. This, in turn, rotates the brake cam, causing the brake shoes to press against the brake drum, generating braking force.
Brake Lines: These connect the various components and transmit compressed air. Brake lines typically use metal tubing or high-pressure rubber hoses, requiring excellent sealing and pressure resistance to ensure no leakage of compressed air during transmission.
Brakes
Drum Brakes: This is a common type of brake in pneumatic braking systems, mainly composed of a brake drum, brake shoes, brake cam, and brake adjusting arm. When the brake chamber pushes the brake adjusting arm to rotate, the brake cam rotates, causing the brake shoes to expand outward and press against the inner surface of the brake drum, generating braking torque through friction.
Disc Brakes: Also used in some high-performance or heavy-duty vehicles, these offer advantages such as good heat dissipation and high braking stability. Disc brakes mainly consist of a brake disc, brake caliper, and brake pads. Braking torque is generated by the brake caliper clamping the brake disc.
