TWO STAGE BRAKE CONTROL VALVE

摘要

TWO STAGE BRAKE CONTROL VALVE A two stage brake valve for communicating fluid pressure to a brake assembly. The valve has a stepped cylinder formed therein in which a high volume piston and high pressure valve are slidably located. The piston and valve define high volume and high pressure chambers respectively. A set of passageways through the piston and valve communicate fluid pressure from the high volume chamber to the high pressure chamber and from the high volume chamber to a reservoir. Relief valve elements located in the passageways regulate fluid communication between the chambers and reservoir. A motion responsive relief valve comprising a ring and groove is also disclosed which provides an orifice function and facilitates refilling of the first chamber. One embodiment includes a highly compact relief assembly valve assembly having dual poppets which act to communicate fluid pressure from the first chamber to either the second chamber or the reservoir. The compact nature of the brake valve assembly will also permit incorporation of a differential lock valve assembly in the same valve body.