# US 2019/0316488 A1 · Gas turbine engine > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0316488 A1 - Document ID: US20190316488A1 - Status: Published application - Kind: A1 - Application number: 16/382,923 - Filed: 2019-04-12 - Published: 2019-10-17 - Earliest claimed: 2018-04-17 - Assignees: Rolls-Royce Deutschland Ltd & Co KG; ROLLS-ROYCE plc - Applicants: Rolls-Royce Deutschland Ltd & Co KG; Rolls-Royce plc - Inventors: Stefan MENCZYKALSKI; Stephan UHKOETTER; John R. MASON; David A. EDWARDS; Neil DAVIES; Lynn HAMMOND; David WILLIAMS - Web page: https://patentgrep.com/patent/US20190316488A1 ## CPC - F01D 25/20: using lubrication pumps - F01M 1/02: using lubricating pumps (pumps in general F04; lubricating pumps per se F16N) - F01M 1/18: Indicating or safety devices (concerning lubricant level F01M11/06, F01M11/12) - F02C 7/06: Arrangements of bearings (bearings F16C); Lubricating ({of turbo machines F01D25/18; of machines or} engines in general F01M) - F02C 7/14: of fluids in the plant {, e.g. lubricant or fuel (F02C7/185 takes precedence)} - F02C 7/36: 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) - F02K 3/06: with front fan - F05D 2260/40311: of the epicyclical, planetary or differential type - F05D 2260/84: Redundancy - F05D 2260/98: Lubrication - F16N 2210/02: Turbines - F16N 2260/00: Fail safe - Y02T 50/60: Efficient propulsion technologies, e.g. for aircraft - F01D: NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES (machines or engines for liquids F03; non-positive displacement pumps F04D) - F01M: LUBRICATING OF MACHINES OR ENGINES IN GENERAL; LUBRICATING INTERNAL COMBUSTION ENGINES; CRANKCASE VENTILATING - F02C: GAS-TURBINE PLANTS; AIR INTAKES FOR JET-PROPULSION PLANTS; CONTROLLING FUEL SUPPLY IN AIR-BREATHING JET-PROPULSION PLANTS (construction of turbines F01D; jet-propulsion plants F02K; construction of compressors or fans F04; generating combustion products of high pressure or high velocity F23R; using gas turbines in compression refrigeration plants F25B11/00) - F02K: JET-PROPULSION PLANTS (features of jet-propulsion plants common to gas-turbine plants, air intakes or fuel supply control of air-breathing jet-propulsion plants F02C7/00, F02C9/00) - F05D: INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS - F16N: LUBRICATING - Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION ## Abstract A gas turbine engine includes a gearbox receiving input from a core shaft and driving a fan at a lower speed than the core shaft. First and second oil circuits fluidly couple with an inlet and outlet of the gearbox. A third oil circuit fluidly couples with an inlet and outlet of the gearbox. The outlet of the gearbox includes a device directing oil from the gearbox to the first oil circuit, to the second oil circuit and to the third oil circuit when feeding to the gearbox exceeds a predefined oil flow rate, or deviates an operational value corresponding with that oil flow rate, and directs oil from the gearbox to the third oil circuit when feeding to the gearbox is the predefined flow rate or is a corresponding operational value or is greater than or equal to a further corresponding operational value. ## Claims ### Claim 1 A gas turbine engine for an aircraft comprising: an engine core comprising at least one turbine, at least one compressor and at least one shaft connecting the turbine to the compressor; a fan located upstream of the engine core, the fan comprising a plurality of fan blades; a gearbox that receives an input from the shaft and outputs drive to the fan so as to drive the fan at a lower rotational speed than the shaft; a first oil circuit, a second oil circuit and at least a third oil circuit; the first oil circuit, the second oil circuit and the third oil circuit fluidly coupled with at least one inlet of the gearbox as well as with at least one outlet of the gearbox; the first oil circuit and the second oil circuit each including at least one pump driven by the shaft; the third oil circuit including a pump; and the outlet of the gearbox including a device configured to direct oil from the gearbox to the first oil circuit and/or to the second oil circuit and/or to the third oil circuit when the feeding to the gearbox is exceeding a predefined oil flow rate, or is deviating at least one operational value corresponding with that oil flow rate, and is configured to direct the oil from the gearbox to the third oil circuit when the feeding to the gearbox is less than or equal to the predefined flow rate or is less than or equal to at least one corresponding operational value or is greater than or equal to at least one further corresponding operational value. ### Claim 2 (depends on 1) The gas turbine engine according to claim 1, wherein: the turbine is a first turbine, the compressor is a first compressor, and the shaft is a first core shaft; the engine core further comprises a second turbine, a second compressor, and a second core shaft connecting the second turbine to the second compressor; and the second turbine, second compressor, and second core shaft are arranged to rotate at a higher rotational speed than the first core shaft. ### Claim 3 (depends on 1) The gas turbine engine according to claim 1, wherein: the first oil circuit is including a heat exchanger. ### Claim 4 (depends on 1) The gas turbine engine according to claim 1, wherein: the second oil circuit is including a heat exchanger. ### Claim 5 (depends on 1) The gas turbine engine according to claim 1, wherein: the first oil circuit and the second oil circuit each are including a scavenge pump and a feeding pump driven by the core shaft. ### Claim 6 (depends on 1) The gas turbine engine according to claim 1, wherein: the third oil circuit is including a pump driven by the first core shaft, the second core shaft or by the fan or by a separate drive unit. ### Claim 7 (depends on 1) The gas turbine engine according to claim 1, wherein: the device is including an oil reservoir from which oil received from the gearbox can be directly conducted back into the gearbox back via the third oil circuit, and in the gearbox via the first oil circuit and the second oil circuit, whereby oil is conducted from the oil reservoir only via the third oil circuit directly to the inlet of the gearbox as long as a filling level of the oil reservoir is less than a defined filling level of the oil reservoir, and oil can be directed via the first oil circuit and via the second oil circuit to the oil tank as soon as the defined filling level of the oil reservoir is reached. ### Claim 8 (depends on 1) The gas turbine engine according to claim 1, wherein: the device is including a first valve unit and a second valve unit whereby the first valve unit is configured to block the connection between the outlet of the gearbox and the inlet of the oil tank via the first oil circuit, and is configured to unblock the connection between the outlet of the gearbox and the inlet of the gearbox via the third oil circuit as long as the feeding to the gearbox from the first oil circuit is less than or equal to the predefined oil flow rate or is less than or equal to at least one corresponding operational value or is greater than or equal to at least one further corresponding operational value. ### Claim 9 (depends on 8) The gas turbine engine according to claim 8, wherein: the second valve unit is configured to block the connection between the outlet of the gearbox and the inlet of the gearbox via the second oil circuit as long as the feeding to the gearbox from the second oil circuit is less than or equal to the predefined oil flow rate or is less than or equal to at least one corresponding operational value or is greater than or equal to at least one further corresponding operational value. ### Claim 10 (depends on 8) The gas turbine engine according to claim 8, wherein: the first valve unit is comprising a solenoid valve and a 5/2 directional control valve whereby the solenoid valve is configured to apply a feeding pressure in the first oil circuit upstream of the inlet of the gearbox to a control surface of a valve control spool of the 5/2 directional control valve in a first operational state of the solenoid valve. ### Claim 11 (depends on 10) The gas turbine engine according to claim 10, wherein: a control line between the solenoid valve and the 5/2 directional control valve is fluidly coupled upstream of the 5/2 directional control valve with the scavenge pump by a throttle. ### Claim 12 (depends on 8) The gas turbine engine according to claim 8, wherein: the second valve unit is comprising a solenoid valve and a 2/2 directional control valve whereby the solenoid valve is configured to apply a feeding pressure in the second oil circuit upstream of the inlet of the gearbox to a control surface of a valve control spool of the 2/2 directional control valve in a first operational state of the solenoid valve. ### Claim 13 (depends on 12) The gas turbine engine according to claim 12, wherein: a control line between the solenoid valve and the 2/2 directional control valve is fluidly coupled upstream of the 2/2 directional control valve with the scavenge pump by a throttle. ### Claim 14 (depends on 1) The gas turbine engine according to claim 1, wherein: the first oil circuit and the second oil circuit are fluidly coupled with an inlet of an oil tank as well as with an outlet of the oil tank, and the first oil circuit and the second oil circuit are configured to receive oil from the oil tank and to direct the received oil to the gearbox. ### Claim 15 (depends on 1) The gas turbine engine according to claim 1, wherein: a throttle is positioned between the inlet of the gearbox and the feeding pump of the second oil circuit.