System and method for detecting a mechanical transmission failure

Patent metadata

Field	Value
Publication number	US-2025244203-A1
Application number	US-202418423715-A
Country	US
Kind code	A1
Filing date	Jan 26, 2024
Priority date	Jan 26, 2024
Publication date	Jul 31, 2025
Grant date	—

Abstract

Methods and systems for detecting a torque transmission failure in an aircraft power plant are provided. The system comprises a hydrostatic transmission for transmitting torque between a first shaft and a second shaft using hydraulic fluid, an a failure detector including a sensor configured to detect a pressure change in the hydraulic fluid. The failure detector is configured to generate an output indicative of the torque transmission failure in response to the pressure change having crossed a threshold.

First claim

1 . A method of detecting a mechanical transmission failure, the method comprising:
transmitting torque between a first shaft and a second shaft via a hydrostatic transmission operating with a hydraulic fluid at an expected pressure; and when the torque is being transmitted between the first shaft and the second shaft, detecting the mechanical transmission failure by detecting a pressure change in the hydraulic fluid from the expected pressure.

2 . The method as defined in claim 1 , comprising:
delivering the hydraulic fluid from a pump of the hydrostatic transmission to a motor of the hydrostatic transmission at a first pressure; and returning the hydraulic fluid from the motor of the hydrostatic transmission to the pump of the hydrostatic transmission at a second pressure, wherein:
the expected pressure includes an expected value of a difference between the first pressure and the second pressure; and
the pressure change includes a deviation from the expected value of the difference between the first pressure and the second pressure.

3 . The method as defined in claim 2 , wherein the mechanical transmission failure is a shaft shear.

4 . The method as defined in claim 2 , comprising measuring the difference in pressure between the first pressure and the second pressure using a delta pressure sensor.

5 . The method as defined in claim 1 , comprising initiating a mitigating action in response to detecting the mechanical transmission failure.

6 . The method as define in claim 1 , comprising:
driving the first shaft with a thermal engine; transmitting the torque from the first shaft to the second shaft via the hydrostatic transmission; driving a compressor with the second shaft; and supplying compressed air from the compressor to the thermal engine.

7 . The method as define in claim 1 , comprising:
driving a turbine using exhaust gas from a thermal engine drivingly connected to the first shaft; driving the second shaft with the turbine; and transmitting the torque from the second shaft to the first shaft via the hydrostatic transmission.

8 . The method as define in claim 7 , wherein:
the turbine is part of a turbo-compressor; the method includes:
driving a compressor of the turbo-compressor with the turbine; and
supplying compressed air from the compressor to the thermal engine.

9 . The method as defined in claim 1 , wherein:
the first shaft drivingly connects a thermal engine to the hydrostatic transmission; the second shaft drivingly connects a turbine to the hydrostatic transmission; and the method includes driving the turbine with exhaust gas from the thermal engine.

10 . The method as defined in claim 9 , comprising:
driving a compressor with the turbine; and supplying compressed air to the thermal engine using the compressor.

11 . The method as defined in claim 10 , comprising stopping a fuel flow to the thermal engine in response to detecting the mechanical transmission failure.

12 . A mechanical transmission system with failure detection, the system comprising:
a hydrostatic transmission configured to transmit torque between a first shaft and a second shaft using hydraulic fluid; and a failure detector including a sensor configured to detect a pressure change in the hydraulic fluid, the failure detector being configured to generate an output indicative of a torque transmission failure in response to the pressure change having crossed a threshold.

13 . The mechanical transmission system as defined in claim 12 , wherein:
the hydrostatic transmission includes:
a first conduit conveying the hydraulic fluid from a pump of the hydrostatic transmission to a motor of the hydrostatic transmission during operation of the hydrostatic transmission; and
a second conduit conveying the hydraulic fluid from the motor to the pump during operation of the hydrostatic transmission; and
the pressure change includes a change in a difference in pressure of the hydraulic fluid in the first conduit and the hydraulic fluid in the second conduit.

14 . The mechanical transmission system as defined in claim 13 , wherein the sensor is a delta pressure sensor operatively connected to the first conduit and to the second conduit.

15 . An aircraft power plant with shaft shear mitigation, the aircraft power plant comprising:
a thermal engine drivingly connectable to an air mover configured to propel an aircraft; a hydrostatic transmission for transmitting torque between the thermal engine and a shaft using hydraulic fluid; a sensor for detecting a pressure of the hydraulic fluid; and a computer operatively connected to the sensor and configured to initiate a mitigating action when the pressure of the hydraulic fluid is indicative of a shaft shear event causing a load change on the hydrostatic transmission.

16 . The aircraft power plant as defined in claim 15 , wherein:
the hydrostatic transmission includes:
a first conduit conveying the hydraulic fluid from a pump of the hydrostatic transmission to a motor of the hydrostatic transmission during operation of the hydrostatic transmission; and
a second conduit conveying the hydraulic fluid from the motor to the pump during operation of the hydrostatic transmission; and
the pressure of the hydraulic fluid is indicative of a shaft shear event when a change in a difference in pressure of the hydraulic fluid in the first conduit and the hydraulic fluid in the second conduit has crossed a threshold.

17 . The aircraft power plant as defined in claim 16 , wherein:
the shaft is drivingly connected to a turbo-compressor; a turbine of the turbo-compressor is configured to be driven using exhaust gas from the thermal engine; a compressor of the turbo-compressor is configured to be driven by the turbine; and the compressor is configured to supply compressed air for combustion in the thermal engine.

18 . The aircraft power plant as defined in claim 17 , comprising a speed-changing gear train operatively connected between the thermal engine and the turbo-compressor.

19 . The aircraft power plant as defined in claim 18 , wherein the aircraft power plant is a hybrid aircraft power plant including an electric motor drivingly connectable to the air mover.

20 . The aircraft power plant as defined in claim 19 , wherein the mitigating action includes stopping a fuel delivery to the thermal engine.

Assignees

• Pratt & Whitney Canada

Inventors

• Lu Xuening
• Meshkinfam Ezzat
• Plamondon Etienne
• Ricci Thomas Trevor

Classifications

• F05D2260/83

  Testing, e.g. methods, components or tools therefor · CPC title

• F05D2260/406

  through hydraulic systems · CPC title

• F02C7/36

  Power transmission arrangements between the different shafts of the gas turbine plant, or between the gas-turbine plant and the power user ({F02C3/107 - F02C3/13 and} F02C7/32 take precedence; couplings for transmitting rotation F16D; gearing in general F16H) · CPC title

• F01D21/003

  Arrangements for testing or measuring (for measuring vibrations G01H) · CPC title

• B64D45/00

  Aircraft indicators or protectors not otherwise provided for · CPC title