Sunday, April 20, 2014
Hydro Max™ Hydraulic Brake Booster and Master Cylinder Technical Manual
It is powered by either the power steering pump or other hydraulic source. The backup pump provides a secondary power source for the hydraulic booster and is controlled by the integral flow switch. The master cylinder is a split system type with separate fluid chambers, pistons and outlet ports for the front and rear brake circuits. A differential pressure switch, fluid level indicator switch, and remote reservoir are also available. During normal system operation, (refer to Figure 4) fluid flow from a hydraulic power source (usually the power steering pump) enters the inlet port of the Hydro-MaxTM booster, flows through the power piston, around the throttle valve and through the flow switch, exiting through the outlet port. Force applied to the brake pedal by the vehicle operator is multiplied by the lever ratio of the pedal mechanism to move the pedal rod of the booster. This movement closes the throttle valve, which restricts flow. This restriction of flow, which results in a pressure increase acting on the power piston, applies an amplified force to the master cylinder primary piston. A reaction piston, inside the power piston subassembly, provides the driver “pedal feel” during an application of the brake pedal. Fluid flow through the flow switch opens the backup pump electrical circuit during normal operation. A separate check valve in the backup pump prevents back-flow through the pump during normal power applications. In the event normal flow from the power source is interrupted, the backup pump provides the power at a reduced rate for stopping. See Figure 3 for performance curve. Upon flow interruption, the integral flow switch closes, energizing a relay, providing electrical power to the backup pump. During backup operation, the pump re-circulates fluid within the booster assembly with pressure built on demand via the throttle valve. Fluid is retained within the booster by the inlet port check valve.
Download: Hydro-Max™ Hydraulic Brake Booster and Master Cylinder Technical Manual
