Hydrostatic mechanical vehicle transmission

摘要

The simplified transmission has a first hydraulic unit (25) on the input shaft (10) and a second, variable hydraulic unit (30) on the output shaft (13). A clutch (15) between the input- and output shafts is closed when the output shaft speed exceeds a preset level. This provides a direct mechanical transmission for higher speeds, with the hydraulic output drive set at zero drive for minimum drag. The mechanical drive comprises an epicyclic drive or a geared drive. The point at which the clutch is engaged is derived from a program related to the speed of the output shaft and the throttle setting. The hydraulic transmission operates at output speed from zero speed to about 20% of the maximum.