UNA VALVULA DE CONTROL DE PRESION VARIABLE, PARTICULARMENTE APLICABLE A TRANSMISIONES AUTOMATICAS

摘要

A pressure control valve 12 includes a system relief valve 14 and a system regulator valve 16. The system relief valve includes a spring-loaded ball 18 which co-operates with a seat 20 and is subject to the action of an external mechanical bias element 62 to control the pressure setting thereof. The spring 22 also acts on the system regulator valve such that the pressure setting thereof changes with the pressure setting of the system relief valve. The system relief valve is always set to a pressure value higher than the system regulator valve, and operates only in response to a significant pressure overloading if the system regulator valve should be inoperable. The system regulator valve can include one or more bias chambers 78, 86 to which bias pressure signals can be communicated to provide a wider separation between the relief and regulated pressure settings if desired.