Zahnradfabrik Friedrichshafen, Ag.

Werner Vetter

Anton Ott

Karlmann Hamma

Arun Chatterjee

A hydrostatic torque converter has a hydrostatic transmission and a stepped or gear transmission shiftable under load by selective actuation of respective clutches assigned to the gear trains. The variable-displacement pump is controlled hydrostatically to follow the switchover between clutches with the control pressure to the servocontrolling the displacement of the pump being regulated in response to the fluid pressures of the clutches through respective pressure modulation valves. As a consequence, the hydrostatic transmission compensates for the jump resulting from the shifting of the steps of the gear transmission and follows the stepping of the gear transmission outside the forced actuation of the transmission (positive switching overlap of the shifting clutches) in dependence upon the progress of load transfer from the released to the engaged clutch.

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Friedrichshafen, Germany

Werner Vetter