Infinitely variable hydrostatic transmission drive

Claim 1

A system for propelling vehicles comprising an infinitely variable hydrostatic transmission drive having a plurality of transmission motors and a common adjustable transmission drive pump feeding the motors; and wherein the motors include at least one variable displacement motor which is variable from full absorption volume to minimum absorption volume, and at least one fixed displacement motor, said motors being connected in a parallel hydraulic circuit; said system further comprises a common back gearing having a common output, and a shift coupling; wherein at least one of said motors operates via said common back gearing with said common output, said shift coupling being operable to connect the variable displacement motor with the common output, said shift coupling being operative at different vehicle speeds to effect connection and disconnection of the variable displacement motor to accomplish a desired vehicular speed; and said variable displacement motor is operative to undergo a transition from the full absorption volume to the minimum absorption volume upon a disconnection of said first variable displacement motor from said common output by said shift coupling.

Claim 2

A system for propelling vehicles comprising an infinitely variable hydrostatic transmission drive having a plurality of transmission motors and a common adjustable transmission drive pump feeding the motors; and wherein the motors include at least one variable displacement motor which is variable from full absorption volume to minimum absorption volume, and at least one fixed displacement motor, said motors being connected in a parallel hydraulic circuit; said system further comprises a common back gearing having a common output, and a shift coupling; wherein at least one of said motors operates via said common back gearing with said common output, said shift coupling being operable to connect the variable displacement motor with the common output, said shift coupling being operative at different vehicle speeds to effect connection and disconnection of the variable displacement motor to accomplish a desired vehicular speed; and said variable displacement motor is operative to undergo a transition from the full absorption volume to the minimum absorption volume upon a disconnection of said first variable displacement motor from said common output by said shift coupling.

Claim 9

A method of operating a transmission drive for a self-propelled vehicle having a plurality of hydraulic transmission motors fed by a common adjustable transmission drive pump, the motors including a variable displacement motor and a fixed displacement motor, the motors operating through a common gearing having a common output, the gearing including a shift coupling with a shaft of the common output, the method comprising the steps of: for the driving of the vehicle, feeding the transmission motors, said motors being set to full-absorption volume, and increasing a displacement volume of the transmission-drive pump; upon attaining maximum displacement volume of the transmission-drive pump, operating the variable displacement motor by continuously increasing a displacement volume thereof to a maximum value for obtaining efficient speed of rotation; after reaching the maximum displacement volume of the variable displacement motor, altering the displacement volume of the variable displacement motor to a self-locking position, reducing the displacement volume of the transmission-drive pump by an amount which corresponds to a last absorption volume of the variable displacement motor, and disconnecting the variable displacement motor from the output by the shift coupling; and increasing the displacement volume of the transmission-drive pump again increasingly to the maximum displacement volume, a highest drive speed of the vehicle then being reached.

Claim 10

A method of operating a transmission drive for a self-propelled vehicle having a plurality of hydraulic transmission motors fed by a common adjustable transmission drive pump, the motors including a variable displacement motor and a fixed displacement motor, the motors operating through a common gearing having a common output, the gearing including a shift coupling with a shaft of the common output, the method comprising the steps of: for the driving of the vehicle, feeding the transmission motors, said motors being set to full-absorption volume, and increasing a displacement volume of the transmission-drive pump; upon attaining maximum displacement volume of the transmission-drive pump, operating the variable displacement motor by continuously increasing a displacement volume thereof to a maximum value for obtaining efficient speed of rotation; after reaching the maximum displacement volume of the variable displacement motor, altering the displacement volume of the variable displacement motor to a self-locking position, reducing the displacement volume of the transmission-drive pump by an amount which corresponds to a last absorption volume of the variable displacement motor, and disconnecting the variable displacement motor from the output by the shift coupling; and increasing the displacement volume of the transmission-drive pump again increasingly to the maximum displacement volume, a highest drive speed of the vehicle then being reached.

Claim 12

A method of operating a transmission drive for a self-propelled vehicle having a plurality of hydraulic transmission motors bed by a common adjustable transmission drive pump, the motors including a first and a second variable displacement motor, the motors operating through a common gearing having a common output, the gearing including a shift coupling with a shaft of the common output, the method comprising the steps of: for the driving of the vehicle, feeding the transmission motors, which are set to full-absorption volume, and increasing a displacement volume of the transmission-drive pump; upon attaining maximum displacement volume of the transmission-drive pump, operating the first variable displacement motor by continuously increasing a displacement volume thereof to a maximum value for obtaining efficient speed of rotation; after reaching the maximum displacement volume of the first variable displacement motor, altering the displacement volume of the first variable displacement motor to a self-locking position, reducing the displacement volume of the transmission-drive pump an amount which corresponds to a last absorption volume of the first variable displacement motor, and disconnecting the first motor from the output by operating the shift coupling; and increasing the displacement volume of the transmission-drive pump again, increasingly to the maximum displacement volume and, thereupon, operating the second variable displacement motor by continuously increasing the displacement volume thereof to a maximum value for obtaining efficient speed of rotation, a highest drive speed of rotation of the output then being achieved.

Claim 13

A method of operating a transmission drive for a self-propelled vehicle having a plurality of hydraulic transmission motors bed by a common adjustable transmission drive pump, the motors including a first and a second variable displacement motor, the motors operating through a common gearing having a common output, the gearing including a shift coupling with a shaft of the common output, the method comprising the steps of: for the driving of the vehicle, feeding the transmission motors, which are set to full-absorption volume, and increasing a displacement volume of the transmission-drive pump; upon attaining maximum displacement volume of the transmission-drive pump, operating the first variable displacement motor by continuously increasing a displacement volume thereof to a maximum value for obtaining efficient speed of rotation; after reaching the maximum displacement volume of the first variable displacement motor, altering the displacement volume of the first variable displacement motor to a self-locking position, reducing the displacement volume of the transmission-drive pump an amount which corresponds to a last absorption volume of the first variable displacement motor, and disconnecting the first motor from the output by operating the shift coupling; and increasing the displacement volume of the transmission-drive pump again, increasingly to the maximum displacement volume and, thereupon, operating the second variable displacement motor by continuously increasing the displacement volume thereof to a maximum value for obtaining efficient speed of rotation, a highest drive speed of rotation of the output then being achieved.