Patent ID: 7942778
Filing Date: 2011-05-17
Classification: B60K,F16H

Abstract:
1. A hydromechanical variable speed transmission including outer and inner differential gear trains each having planet pinions meshing with two coaxial side gears, the side gears of the outer differential gear train being ring gears one of which is an input ring gear and the other of which rotatably drives the inner differential gear train, the side gears of the inner differential gear train respectively rotatably driving two coaxial output shafts which extend axially outwards through the ring gears of the outer differential gear train, the outer differential gear train rotatably driving a hydraulic motor which is fluidly coupled by a hydraulic circuit to rotatably drive a hydraulic pump having a pump control for changing the displacement of the hydraulic pump in response to rotation thereof, wherein the hydraulic motor, the hydraulic circuit and the hydraulic pump are coaxially mounted on a hollow input shaft between the input ring gear and a driving ring gear and the pump control is fixed from rotation to thereby isolate the input ring gear from torque recirculation.