Patent ID: 6997838
Filing Date: 2006-02-14
Classification: F16H

Abstract:
1. A hydromechanical transmission for providing a continuously variable speed/torque driving connection between a prime mover and ground engaging members of a vehicle, comprising: a housing having internal cavities for holding operating assemblies of said transmission; an axial piston pump having rotating and non-rotating elements, said rotating elements including a pump cylinder block and a ring of axial pump pistons in cylinders in said pump cylinder block, said pump rotating elements having a center of mass and an axis of pump rotation that passes through said center of mass; said non-rotating pump elements include a pump reaction member mounted for tilting about a first tilting axis, said first tilting axis lying transverse to said axis of pump rotation; said pump reaction member being axially juxtaposed to said pump rotating elements and in contact therewith for reacting axial force exerted by said pump rotating elements and disposed to drive said pump pistons into said pump cylinders for converting torque on said pump rotating elements into hydraulic pressure; an axial piston motor having rotating and non-rotating motor elements, said rotating motor elements include a motor cylinder block and a ring of axial motor pistons in cylinders in said cylinder block, said motor rotating elements having a center of mass and an axis of rotation that passes through said motor cylinder block center of mass; said non-rotating motor elements include a motor reaction member mounted for tilting about a second tilting axis, said second tilting axis lying transverse to said motor cylinder block axis of rotation; said motor reaction member being axially juxtaposed to said motor rotating elements and in contact therewith for reacting axial force exerted by said motor rotating elements and disposed to enable said motor pistons to exert forces at an angle to said motor axis of rotation for converting axial force in said motor pistons into torque, said pump and said motor disposed side-by-side in said housing with said axes of rotation approximately parallel to each other; a stationary manifold fixed to said housing, having one surface in contact with said rotating pump element and having fluid passages opening in said one surface in fluid communication with said pump cylinders through a pump/manifold interface; said stationary manifold having a second surface in contact with said rotating motor element and having fluid passages opening in said second surface in fluid communication with said motor cylinders through a motor/manifold interface; said stationary manifold having internal fluid passages for conveying fluid pressurized in said pump directly to said motor, and for conveying spent fluid displaced from said motor back to said pump; a tilt control coupled to tilting apparatus attached to said non-rotating pump element and to said non-rotating motor element, said tilting apparatus mounted in said housing for tilting said non-rotating elements about said first and second tilting axes to desired angles of tilt; an epicyclic gear set having a first gear element coupled to an input shaft of said transmission, a second gear element coupled to and driving said rotating element of said pump, and a third gear element engaged with and between said first and said second gear elements, said third gear element having a connected spur gear that is coupled to said rotating element of said motor and to an output shaft for driving said ground engaging members of said vehicle; whereby reaction torque from said pump is summed with torque from said motor in said spur gear for output through said output shaft.