The Basics of Hydraulic Control Systems

Hydraulic Control System

Hydraulics are used in a variety of everyday applications, ranging in application from automotive vehicles to aerospace transports. One of the best examples of a hydraulic application is the hydraulic brake. A hydraulic brake is a breaking mechanism that relies on brake fluid to transfer pressure from the controlling mechanism to the breaking mechanism. Most commonly, brake fluid contains ethylene glycol, the same organic compound that is primarily used as the raw material in manufacturing polyester fibers, and industrial products like antifreeze.

The most common form of hydraulic brakes are used in passenger vehicles, motorcycles and mopeds. Generic systems consist of a brake pedal or lever, an actuating rod, and a master cylinder assembly that contains a piston assembly. Additionally, there is a return spring, a series of seals and a fluid reservoir. The brake system also contains a reinforced hydraulic line and a brake caliper assembly, which houses the brake pads and pistons. Calipers can be either floating or fixed, depending on whether or not it moves with the disc. The thermally conductive brake pads and the brake disc are attached to an axle.

The Hydraulic Control System works when the brake pedal is pressed downward. This enables the actuating rod to generate force on the piston in the master cylinder. This proceeds to cause the fluid from the fluid reservoir to move into a containment chamber, resulting results in an increase in the pressure throughout the entire hydraulic system. Seated O-rings around the piston prevent fluid from leaking in the system. The system is a self-contained, meaning the system will work properly without any extra fluid or oil to be added regularly. Fluid should not leak out, unless there is a flawed or damaged component such as a seal.

Force is then applied by the brake caliper to the brakes pads, pushing the pads against the spinning rotor. The friction that is caused between the pads and the rotor causes a breaking torque to be generated. This breaking torque slows the vehicle. When the brake pedal is released it allows the springs to return the master piston back into its starting position. This motion relieves the hydraulic pressure on the caliper, which allows the brake piston in the caliper assembly to slide back into its housing and then causes the brake pads to release the rotor.

While it’s a simple concept, the actual Hydraulic Control System is designed with complex and intricate mechanics. It is likely this braking technology will continue to be integrated into mobile machines for many years to come.