Wabco Fahrzeugbremsen Gmbh

Klaus-Dieter Bergemann

Bernd-Joachim Kiel

Karl-Heinz Deike

Heinz-Werner Konig

The invention relates to a pneumatic relay valve for regulating output pressure in proportion to a control pressure. The relay valve includes a first piston member which is acted on by the control pressure and a second piston member which is acted on by the input pressure. A compression spring is located between the two relay piston members. The strength of the compression spring determines the height of a predetermined minimum controlled pressure even if the input pressure is subsequently lost or drops to a low value. In addition, the output pressure of a receiver can be maintained at a specific adjustable level which may be below the maximum pressure value of the input pressure due to the compression spring located between the two relay piston members.

Pneumatic relay valve

This invention relates to a control system for a pneumatically cushioned vehicle having at least a first and a second pneumatically cushioned axle. The pressure in the air spring bellows of the second axle is controlled in accordance with the air spring bellows of the first axle. The air spring bellows of the second axle are connected to a source of supply pressure by a pneumatic relay valve. The relay valve includes a control inlet which is connected with the air spring bellows of the first axle. The relay valve is designed in such a way, that if no pressure or a relatively low control pressure is present at the control inlet, the pressure at an outlet port of the relay valve leading to the air spring bellows of the second axle will be maintained at a minimum value. The relay valve includes a first control chamber and a second control chamber which are separated by a relay piston. The piston of the relay valve is biased by a compression spring which establishes a predetermined level of the pressure initially entering the air spring bellows of the second axle in the event of subsequent pressure loss.

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Hanover, Germany

Klaus-Dieter Bergemann