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A hydraulic ground propulsion system for an aircraft. The system comprises a wheel, axel, an aircraft power interface device, an electric motor, a hydraulic system, a drive assembly and a controller. The wheel is rotatably coupled to the wheel axel. The aircraft power interface device interfaces an

A hydraulic ground propulsion system for an aircraft. The system comprises a wheel, axel, an aircraft power interface device, an electric motor, a hydraulic system, a drive assembly and a controller. The wheel is rotatably coupled to the wheel axel. The aircraft power interface device interfaces an aircraft power source. The electric motor is coupled to the aircraft power interface device and receives power from the aircraft power source through the aircraft power interface device. The hydraulic system is driven by the electric motor. The drive assembly mechanically couples the wheel axel to the hydraulic system. The drive assembly is mechanically driven by the hydraulic system. The drive assembly transfers energy from the hydraulic system to the wheel axel. The controller controls the electric motor and the hydraulic system based upon a pilot torque command.

대표청구항 ▼

1. A ground propulsion system for an aircraft comprising: at least one wheel axel;at least one wheel rotatably coupled to said at least one wheel axel;an aircraft power interface device which interfaces an aircraft power source;an electric motor coupled to the aircraft power interface device that re

1. A ground propulsion system for an aircraft comprising: at least one wheel axel;at least one wheel rotatably coupled to said at least one wheel axel;an aircraft power interface device which interfaces an aircraft power source;an electric motor coupled to the aircraft power interface device that receives power from said aircraft power source through the aircraft power interface device;a hydraulic system driven by the electric motor, said hydraulic system comprising a charge pump having a first and a second end, the first end being attached to a fluid reservoir and the second end being attached to a variable displacement hydraulic pump, said charge pump pumping hydraulic fluid from the fluid reservoir to the variable displacement hydraulic pump, said charge pump being driven by said electric motor;a drive assembly mechanically coupled to said at least one wheel axel and mechanically coupled to said hydraulic system, said drive assembly being mechanically driven by said hydraulic system, said drive assembly transferring energy from said hydraulic system to said at least one wheel axel; anda controller for controlling said electric motor and said hydraulic system based upon a pilot torque command. 2. The ground propulsion system for an aircraft according to claim 1, wherein said electric motor is a constant speed AC motor providing a power source to said hydraulic system. 3. The ground propulsion system for an aircraft according to claim 1, wherein said hydraulic system further comprises: the fluid reservoir for storing the hydraulic fluid for the hydraulic system;the variable displacement hydraulic pump variably supplying a pressurized hydraulic fluid based upon a first displacement control signal from said controller, said electric motor providing displacement torque to said variable displacement hydraulic pump;and a variable displacement hydraulic motor variably providing mechanical energy to said drive assembly based upon a second displacement control signal from said controller, said variable displacement hydraulic motor being supplied with said pressurized hydraulic fluid. 4. The ground propulsion system for an aircraft according to claim 3, wherein said hydraulic system further comprises: a first hydraulic line having a first and second end, said first end being connected to said variable displacement hydraulic pump and said second end being connected to said variable displacement hydraulic motor; anda second hydraulic line having a first and second end, said first end being connected to said variable displacement hydraulic motor and said second end being connected to said variable displacement hydraulic pump. 5. The ground propulsion system for an aircraft according to claim 4, wherein said hydraulic system further comprises: a first hydraulic pressure control line attached to said variable displacement hydraulic pump for adjusting a displacement of said variable displacement pump based upon said first displacement control signal from said controller; anda second hydraulic pressure control line attached to said variable displacement hydraulic motor for adjusting a displacement of said variable displacement motor based upon said second displacement control signal from said controller. 6. The ground propulsion system for an aircraft according to claim 3, wherein said hydraulic system further comprises: a first temperature control system for cooling said hydraulic fluid and pressurized hydraulic fluid based upon a control signal from said controller. 7. The ground propulsion system for an aircraft according to claim 6, wherein said first temperature control system comprises a forced air cooling device. 8. The ground propulsion system for an aircraft according to claim 3, wherein said drive assembly comprises: a gear box coupled to said variable displacement hydraulic motor;a clutch assembly coupled to said at least one wheel axel, said clutch assembly having a first and second position, said first position being an engaged position and said second position being a disengaged position; anda shear assembly having a first end coupled to said gear box and a second end coupled to said clutch assembly. 9. The ground propulsion system for an aircraft according to claim 8, wherein said shear assembly has a mechanical shear point between said gear box and said clutch assembly which breaks a mechanical link between said gear box and said at least one wheel axel to permit the at least one wheel to freely spin if said clutch assembly fails in the engaged position. 10. The ground propulsion system for an aircraft according to claim 8, wherein said gear box comprises at least one gear adapted to rotate in a first direction and a second direction, said first direction moving the aircraft in a forward direction and said second direction moving the aircraft in a reverse direction. 11. The ground propulsion system for an aircraft according to claim 6, further comprising: a second temperature control system for heating said hydraulic fluid when a temperature of said hydraulic fluid is below a preset threshold value. 12. The ground propulsion system for an aircraft according to claim 11, wherein said second temperature control system comprises a temperature sensor and a heating element. 13. The ground propulsion system for an aircraft according to claim 12, wherein said heating element is a resistive heating element. 14. The ground propulsion system for an aircraft according to claim 6, further comprising: a second temperature control system for heating said hydraulic fluid when a viscosity of said hydraulic fluid is below a preset threshold value. 15. The ground propulsion system for an aircraft according to claim 12, wherein said heating element is located in close proximity to said fluid reservoir. 16. The ground propulsion system for an aircraft according to claim 3, wherein said variable displacement hydraulic motor has a neutral mode, and when said aircraft is within a preset period of time prior to landing, said controller activates said variable displacement hydraulic pump with said variable displacement hydraulic motor set to said neutral mode. 17. The ground propulsion system for an aircraft according to claim 2, further comprising an electric motor cooling system for cooling said electric motor. 18. The ground propulsion system for an aircraft according to claim 4, wherein said variable displacement hydraulic pump and variable displacement hydraulic motor are bi-directional. 19. The ground propulsion system for an aircraft according to claim 3, wherein said variable displacement hydraulic motor, said drive assembly, said at least one wheel axel and said at least one wheel are located in a wheel hub. 20. The ground propulsion system for an aircraft according to claim 3, wherein said variable displacement hydraulic pump, said fluid reservoir, said controller and said electric motor are located in a landing gear bay. 21. The ground propulsion system for an aircraft according to claim 1, wherein said controller controlling said electric motor and said hydraulic system based upon a pilot torque command and at least one environmental parameter. 22. The ground propulsion system for an aircraft according to claim 21, wherein said at least one environmental parameter is a wheel speed. 23. The ground propulsion system for an aircraft according to claim 21, wherein said at least one environmental parameter is an aircraft status, said aircraft status being a member of a group consisting of in air and on ground. 24. The ground propulsion system for an aircraft according to claim 21, wherein said at least one environmental parameter is a hydraulic fluid temperature. 25. The ground propulsion system for an aircraft according to claim 21, wherein said at least one environmental parameter is a drain case pressure. 26. The ground propulsion system for an aircraft according to claim 3, wherein said controller independently controls said variable displacement hydraulic pump and said variable displacement hydraulic motor. 27. The ground propulsion system for an aircraft according to claim 3, wherein said at least one wheel comprises a first and second wheel and said at least one wheel axel comprises a first and second wheel axel, said first wheel being rotatably coupled to said first wheel axel and said second wheel being rotatably coupled to said second wheel axel, said system further comprising: a second variable displacement motor;a second drive assembly mechanically coupled to said second wheel axel and mechanically coupled to said second variable displacement motor; andat least one fluid divider which splits said pressurized hydraulic fluid, from said variable displacement pump, between said variable displacement motor and said second variable displacement motor.