Hydraulic structure for a brake system

摘要

A vehicle brake includes a compact module having an inlet port connected to the return-to-sump line of a hydraulic operating system on the vehicle. The module includes a path to a filter mounted on the module for filtering the operating system fluid and a poppet valve for bypassing a clogged filter. Passages in the module direct most of the return line fluid through a poppet valve which develops a source of back pressure substantially lower that system operating pressure in a cavity in the module and returns the fluid to an outlet connected to sump. A portion of the fluid in the cavity is communicated via a charge port in the module to a hydrostatic system to replenish leakage and shuttle flow in the hydrostatic system and to prevent cavitation. The source of back pressure in the module is selectively connected to spring-applied, pressure-released brakes through a four-way solenoid valve housed by the module. To release the brakes, the valve is actuated to direct pressure to one side of each of the brake cylinders. To apply the brakes, the valve is deactuated to pressurize the opposite sides of the cylinders for hydraulically assisted braking.