Patent ID: 6029560
Filing Date: 2000-02-29
Classification: B62D

Abstract:
A fluid pressure operated torque amplifier comprising: a housing having a pressurized fluid inlet leading from a source of pressurized fluid; a torque amplifier unit including a first stationary internally toothed member and a second externally toothed member disposed within the first internally toothed member for orbital motion therein, the teeth of the first internally toothed member and the second externally toothed member intermeshing to form a plurality of expanding and contracting volume chambers for hydraulically generating a motive power; a control valve assembly disposed within the housing adjacent to the torque amplifier unit and adapted to be operated between a neutral position in which a first fluid flow path is established to bypass the volume chambers and a left and a right steering position in which corresponding flow paths are established to supply the pressurized fluid to the volume chambers, the control valve assembly comprising a first rotatable member having an input member extending outwardly from the housing, and a second rotatable follower member telescopingly disposed relative to the first rotatable member, a rotation of the first rotatable member through rotation of the input member causing the first rotatable member and the second rotatable follower member to rotate relative to each other to move the control valve assembly from the neutral position to the left or right position; a first drive shaft disposed within the first rotatable member and having one end drivably connected to the second rotatable follower member and the other end drivingly connected to the second externally toothed member of the torque amplifier unit; a second drive shaft having one end drivably connected to the second externally toothed member of the torque amplifier unit and the other end drivingly connected to an output shaft; characterized in thatthe output shaft has a return fluid outlet leading to a reservoir; the first and second drive shafts have passages formed therein and that when the control valve assembly is in the left or right position, the fluid exiting the volume chambers of the torque amplifier unit flows through the control valve assembly, the passages of the first and second drive shafts and the return fluid outlet of the output shaft into the reservoir.