Differential hydrostatic transmission system

摘要

A hydrostatic transmission system (10) for driving a rotatable member includes a differential (32) having an output (48) coupled with the rotatable member, a first hydrostatic drive (18) having an output (28) coupled to a first input of the differential (32), and a second hydrostatic drive (22) having an output (30) coupled to a second input of the differential (32). The output (28) of the first hydrostatic drive (18) is rotatable in a first selected direction and at a first selected speed. The output (30) of the second hydrostatic drive (22) is rotatable in a second selected direction and at a second selected speed. A rotational speed and direction of the output (48) of the differential (32) is related to the algebraic sum of the rotational speeds and directions of the outputs of the hydrostatic drives (18,22). In one embodiment, the speeds of the first and second drives (18,22) are maintained above a minimum stable threshold, while operating the rotatable drive at very low or zero speed, by selecting the first direction to be opposite the second direction.