Brake valve for dual circuit pneumatic brake systems, particularly for vehicles

摘要

A brake valve for dual circuit pneumatic brake systems is proposed for motor vehicles which have two independent, separately controlled brake systems. A primary piston (18) and a secondary piston (24), which serve for controlling the brake pressure, and associated inlet and outlet valves for the compressed air are arranged in tandem in the operating direction in the valve housing (10). The primary piston (18) is mechanically actuable by way of a final control element (46). The secondary piston (24) is actuated by the pressure in the first brake circuit (20) or by the primary piston (18). Whilst the primary piston (18) is displaceable against the force of at least one return spring (42), the secondary piston (24) is freely movable in the same direction and unloaded by spring reaction forces. It is coupled by means of a coupling element (52) so that it moves together with the primary piston (18) in the opposite direction thereto. If the primary piston (18) closes the venting outlet and opens the compressed air inlet, this occurs practically without any lag even in the case of the secondary piston (24) and the second brake circuit. If the primary piston (18) opens the outlet, the secondary piston (24) is also drawn along by this and opens its outlet without any residual pressure remaining in the second brake circuit (Fig. 1).
<IMAGE>