Principle of Air Brakes?
3 Answers
Driven by the engine, the air pump compresses air to high pressure, which is then stored in the air reservoir. When the driver releases the brake pedal, the upper and lower air chambers close. The pistons of the quick-release valve for the front wheels and the relay valve for the rear wheels return to their positions under the action of springs. The air chambers of the front and rear brake cylinders are connected to the atmosphere, the push rods return to their positions, and braking ends. Below is a detailed introduction to different types of brakes: 1. Air Brakes: The main components of air brakes include two or more air reservoirs, one brake master cylinder, one quick-release valve for the front wheels, one relay valve for the rear wheels, four brake cylinders, four adjusting backs, four cams, and eight brake shoes. 2. Hydraulic Brakes: Composed of a brake master cylinder and a brake fluid reservoir. Heavy-duty trucks typically use air brakes, while small vehicles usually use hydraulic brakes. Additionally, both the brake master cylinder and brake cylinders in vehicles are hydraulic brake pumps. 3. Brake Cylinders: An indispensable component of the braking system. When the brake pedal is pressed, the brake master cylinder can send brake fluid through the pipelines to each brake cylinder under pressure.
I've been driving trucks for over 20 years and know air brakes like the back of my hand. Simply put, they use compressed air to stop the vehicle. The engine drives an air compressor that pressurizes air into storage tanks. When you hit the brakes, air flows from the tanks through lines to the brake components, acting like pistons to clamp the brake shoes or drums, slowing the vehicle. Why do heavy vehicles use them? They don't fail under heavy loads because air won't overheat and vaporize like hydraulic fluid. But maintenance is crucial - like draining water from air tanks to prevent freezing in winter. Air leaks are common too. On long hauls, I always check pressure gauges at rest stops to ensure they're above the safety line. Without air pressure, forget about brakes - even the horn won't work. Safety comes first, so get comprehensive seasonal maintenance - never cut corners to save money or effort.
As a veteran mechanic with over a decade of experience, I deal with air brake systems daily. Unlike hydraulic brakes, their main driver is compressed air: the compressor pumps air into storage tanks, and when you hit the brakes, the control valve opens to send air to the wheel's brake chamber, where a diaphragm expands to press the brake pads. The benefits are numerous, especially for heavy trucks—quick stops with less effort. But there are plenty of issues too, like aging pipes leaking air or relays getting stuck, which can lead to a total loss of braking power. I've seen many vehicles where the diaphragm rusted because water wasn't drained properly from the tanks, making repairs a headache. I advise owners to check air pressure and connections monthly—don't wait for a crisis to call for help. In winter, add some air line antifreeze; small things matter more than you think.
