Patent ID: 8402761
Filing Date: 2013-03-26
Classification: F16H

Abstract:
1. A step-less hydrostatic gear box for a rotary movement transmission comprising: at least a first and second hydrostatic pump, each of said hydrostatic pumps comprising a stator and a rotor, said rotor comprising an axially extending housing receiving at least one radial piston having a bottom portion and a top portion, and wherein said stator comprises an inner surface that contacts the top portion of the at least one radial piston to form at least one working space; an input shaft having a first end coupled to an input drive motor and a second end coupled to the stator of the first hydrostatic pump, said stator of the first hydrostatic pump being connected to the stator of the second hydrostatic pump in a manner so that the stators are driven at a same rotary speed but in opposite rotary directions; an output shaft having a first end coupled to an external load and a second end; a drive shaft coupled to the rotors of the at least first and second hydrostatic pumps, said second end of the output shaft being coupled to the drive shaft; an oil distribution system arranged to distribute oil to the at least two hydrostatic pumps so that said oil fills the at least one working space; and at least one servo system configured to control the distribution of oil from the oil distribution system, wherein the stator and rotor of each of the at least two hydrostatic pumps are arranged so that when oil is distributed to the at least one working space, the rotation of the stators by the input shaft creates hydrostatic pressure driving said rotors in rotation.