# US 2014/0150401 A1 · Geared compressor for 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 2014/0150401 A1 - Document ID: US20140150401A1 - Status: Published application - Kind: A1 - Application number: 14/060,094 - Filed: 2013-10-22 - Published: 2014-06-05 - Earliest claimed: 2012-10-31 - Assignees: Rolls-Royce Deutschland Ltd & Co KG - Applicants: Rolls-Royce Deutschland Ltd & Co KG - Inventors: Gideon Daniel VENTER - Web page: https://patentgrep.com/patent/US20140150401A1 ## CPC - 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) - F02C 3/064: {the compressor having concentric stages} - F02C 3/067: having counter-rotating rotors (F02C3/073 takes precedence) - F02C 3/107: with two or more rotors connected by power transmission - F02C 3/113: with variable power transmission between rotors - F02C 7/32: Arrangement, mounting, or driving, of auxiliaries - F02K 3/04: the plant including ducted fans, i.e. fans with high volume, low pressure outputs, for augmenting the jet thrust, e.g. of double-flow type - F02K 3/06: with front fan - F05D 2260/40311: of the epicyclical, planetary or differential type - 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 ## Abstract A booster assembly for a gas turbine engine having a first rotor assembly comprising a low pressure turbine drivingly connected to a fan via a first shaft and a second rotor assembly comprising a second turbine drivingly connected to a high pressure compressor via a second shaft. The booster assembly comprises a further compressor arranged to be disposed about said common axis between the fan and high-pressure compressor in a direction of flow and a gearing having first and second input rotors and an output rotor. The first input rotor is arranged to be driven by the first rotor assembly and the second input rotor is arranged to be driven by the second rotor assembly such that the output rotor drives the further compressor in dependence upon the difference in rotational speed between the first and second rotor assemblies. ## Claims ### Claim 1 A booster assembly for a gas turbine engine having a first rotor assembly comprising a low pressure turbine drivingly connected to a fan via a first shaft and a second rotor assembly comprising a second turbine drivingly connected to a high pressure compressor via a second shaft, the first and second rotor assemblies arranged to undergo relative rotation in use about a common axis, the booster assembly comprising: a further compressor arranged to be disposed about said common axis between the fan and high-pressure compressor in a direction of flow; and a gearing having first and second input rotors and an output rotor, the first input rotor arranged to be driven by the first rotor assembly and the second input rotor arranged to be driven by the second rotor assembly such that the output rotor drives the further compressor in dependence upon the difference in rotational speed between the first and second rotor assemblies. ### Claim 2 (depends on 1) A booster assembly according to claim 1, wherein the further compressor rotates at a speed greater than that of the first rotor assembly but lower than that of the second rotor assembly. ### Claim 3 (depends on 1) A booster assembly according to claim 1, wherein the gearing comprises an epicyclic gearing. ### Claim 4 (depends on 3) A booster assembly according to claim 3, wherein the output rotor comprises a planet gear carrier or sun gear of the epicyclic gearing. ### Claim 5 (depends on 3) A booster assembly according to claim 3, wherein the first input rotor or second input rotor comprises a ring gear. ### Claim 6 (depends on 1) A booster assembly according to claim 1, wherein the first or second input rotor comprises an extension portion of the respective first or second shaft. ### Claim 7 (depends on 1) A booster assembly according to claim 1, wherein the first or second input rotor is connected to the respective first or second shaft by an intermediate wall or arm which is angled with respect to the common axis. ### Claim 8 (depends on 1) A booster assembly according to claim 1, wherein the output rotor of the gearing is drivingly connected to an electrical machine. ### Claim 9 (depends on 8) A booster assembly according to claim 8, wherein the electrical machine is driven by the output rotor in a generator mode of operation and/or is arranged to drive the output rotor in a starter motor mode of operation. ### Claim 10 (depends on 8) A booster assembly according to claim 8, wherein the output rotor may be connected to or else integral with a rotor of the electrical machine. ### Claim 11 (depends on 10) A booster assembly according to claim 10, wherein the electrical machine rotor comprises one or more magnets. ### Claim 12 (depends on 8) A booster assembly according to claim 8, wherein the electrical machine is disposed about the common axis. ### Claim 13 (depends on 8) A booster assembly according to claim 8, further comprising a brake for any or any combination of the first rotor assembly, second rotor assembly, the first input rotor and/or the second input rotor. ### Claim 14 A gas turbine engine comprising: a first rotor assembly comprising a low pressure turbine drivingly connected to a fan via a first shaft; a second rotor assembly comprising a second turbine drivingly connected to a high pressure compressor via a second shaft, the first and second rotor assemblies arranged to undergo relative rotation in use about a common axis, and a booster assembly having: a further compressor arranged to be disposed about said common axis between the fan and high-pressure compressor in a direction of flow; and a gearing having first and second input rotors and an output rotor, the first input rotor arranged to be driven by the first rotor assembly and the second input rotor arranged to be driven by the second rotor assembly such that the output rotor drives the further compressor in dependence upon the difference in rotational speed between the first and second rotor assemblies.