Double circuit controlled relay valve, especially trailer brake or trailer control valve, for pneumatic vehicle brake systems

摘要

A relay valve controlled by way of two circuits I, II, especially a trailer control or trailer brake valve, for pneumatic brake systems on motor vehicles is equipped with two control pistons (3, 5) provided with seals (6, 8), each piston being connectable to a circuit, arranged adjacently and movable in the same direction in a housing (1), the control piston (3) being equipped with closed piston head and the other control piston (5) carrying a part of the discharge valve (15, 16) which with a double valve body (16) forms the discharge valve (15, 16) whilst an inlet valve (16, 18) is formed between the double valve body (16) and an inlet seat (18). Between the two control pistons (3, 5) a separating piston (4) with seal (7) is provided and carried in a common cylinder (2) with the two control pistons (3, 5). The control piston (3) encloses with the separating piston (4) a chamber (13) connected to the atmosphere. The separating piston (4) is arranged free floating in the common cylinder (2) and with a hollow projection (35) is guided in a sealing manner in the other control piston (5). The chamber (13) between the one control piston (3) and the separating piston (4) is permanently connected to the atmosphere by means of a hollow projection (14) extending through the other control piston (5). The hollow projection (14) of the other control piston (5) is internally guided in a sealing manner on the hollow projection (35) of the separating piston (4) and is externally guided in a sealing manner in an insert (27) fixed in the housing (1). The control chamber (11) of the other control piston (5) can be ventilated and vented via the control line led through the insert (27). IMAGE