Infinitely variable hydrostatic mechanical power shift gearbox

Abstract

The gearbox includes a multi-shaft toothed-wheel planetary gearing and a continuously adjustable hydrostatic transmission having toothed-wheel auxiliary transmission stages and gear-changing clutches. The hydrostatic transmission is associated with a displacement-type machine with constant displacement volume. In the planetary gearing, one shaft forms the input shaft to which the adjustable displacement-type machine is connected. A second shaft of the planetary gearing is connected to the constant-volume displacement-type machine. Third and fourth shafts of the planetary gearing represent coupling shafts. The coupling shafts alternately act via at least two auxiliary transmission stages, also called gears, on the output shaft. The coupling shafts change their speeds in such a manner that one coupling shaft becomes steadily faster and the other one becomes steadily slower. They behave in such a manner that they exhibit equal speeds in one extreme position. In the extreme positions of the hydrostatic transmission, gear-changing clutches handle the gear change free of load and without interruption of traction force when the speeds are synchronous. The automatic transmission is controlled and regulated by electronic and hydraulic means.