Patent ID: 6131475
Filing Date: 2000-10-17
Classification: F16H,Y10T

Abstract:
A transmission control system for a synchromesh gear transmission and alternatively, a powershift transmission, both transmissions establishing a forward and a reverse drive via the engagement and disengagement of a plurality of clutch switching elements, including at least one forward switching element and one reverse switching element, the transmission control system comprising:a single shift valve (SV1) actuated by a first switching device and a second switching device for selecting between one of said forward drive and said reverse drive of said synchromesh gear transmission or said powershift transmission when the transmission is coupled to the transmission control system;a single control valve (SV2) actuated by a third switching device for communicating between the single shift valve and the plurality of clutch switching elements, the control valve having a double function port and a removable shut-off member for blocking said double function port;wherein said intermediate member blocks flow of pressurized medium through the double function port when the shut-off member is connected to the control valve, the flow of pressurized medium through the double function port being unimpeded when the shut-off member is removed from the control valve;the control valve (SV2), in addition to the double function port, further including a first port and a second port (1"", 2"") for receiving pressurized medium from the shift valve (SV1), a third port (3"") connectable with a tank (8) and a forth port and a fifth port (4"", 6"") also connectable with the plurality of clutch switching elements (SEV1, SER).