Relay valve especially trailer brake or trailer control valve for pneumatic vehicle brake systems

摘要

A relay valve which can be controlled by at least one circuit and can be used as a trailer control or trailer brake valve has at least one control piston (3) and a first reaction surface (21) on which the output pressure of the brake chamber (25) acts. A second reaction surface (22) is provided on a reaction piston (17) which, to provide a first point of inflexion in the characteristic of the relay valve, has a retaining spring (28) supported on the housing. Provided between the control piston (3) and the reaction piston (17) are mechanical stops (30, 31) which permit a travel (32). To provide a second point of inflexion in the characteristic of the relay valve, the second reaction surface (22) is allocated a transmission spring (33) between the control piston (3) and the reaction piston (17) and this spring comes to rest on the control piston (3) only when the first point of inflexion is reached, its compression being limited by the meeting of the stops (30, 31). IMAGE