# US 12,006,876 B2 · Gas turbine engine front section > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,006,876 B2 - Document ID: US12006876B2 - Status: Granted - Kind: B2 - Application number: 17/527,542 - Filed: 2021-11-16 - Published: 2022-03-10 - Granted: 2024-06-11 - Earliest claimed: 2013-05-09 - Assignees: Rtx Corporation - Applicants: Rtx Corporation - Inventors: Frederick M. Schwarz; William G. Sheridan - Web page: https://patentgrep.com/patent/US12006876B2 ## 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) - 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 turbofan engine includes a geared architecture for driving a fan about an axis. The geared architecture includes a sun gear rotatable about an axis, a plurality of planet gears driven by the sun gear and a ring gear circumscribing the plurality of planet gears. A carrier supports the plurality of planet gears. The geared architecture includes a power transfer parameter (PTP) defined as power transferred through the geared architecture divided by gear volume multiplied by a gear reduction ratio. ## Claims ### Claim 1 A gas turbine engine comprising: a propulsor section; a compressor section including a compressor entrance passage including an inlet disposed at an inlet diameter and an outlet to the compressor disposed at an outlet diameter; a combustor receiving airflow from the compressor section and generating a high-energy flow; a turbine section driven by the high-energy flow; a geared architecture configured to be driven by the turbine section for driving the propulsor section at a speed different than the turbine section, wherein a geared architecture power transfer parameter (PTP) is defined as power transferred through the geared architecture divided by gear volume multiplied by a gear reduction ratio and is between 219 and 328. ### Claim 2 (depends on 1) The gas turbine engine as recited in claim 1, wherein the geared architecture includes an axial length between 3.03 and 4.60 inches. ### Claim 3 (depends on 2) The gas turbine engine as recited in claim 2, wherein the gas turbine engine includes an overall axial distance from a forward part of the propulsor section to a forward bearing assembly and a ratio of the overall axial distance to the axial length of the geared architecture is between 6 and 18. ### Claim 4 (depends on 2) The gas turbine engine as recited in claim 2, wherein the geared architecture comprises an epicyclic gear system including a ring gear circumscribing a plurality of planetary gears driven by a sun gear and a carrier supporting the planetary gears and the gear volume is defined within a space bounded by the ring gear and outer periphery of the carrier. ### Claim 5 (depends on 4) The gas turbine engine as recited in claim 4, wherein the gear volume is between 526 in3 and 790 in3. ### Claim 6 (depends on 1) The gas turbine engine as recited in claim 1, wherein the propulsor section includes a fan hub supporting a plurality of fan blades, the fan hub including a hub diameter and the plurality of fan blades including a tip diameter with a ratio of the hub diameter to the tip diameter is between 0.24 and 0.36. ### Claim 7 (depends on 6) The gas turbine engine as recited in claim 6, wherein a ratio of the inlet diameter to the outlet diameter is between 1.22 and 1.82. ### Claim 8 (depends on 7) The gas turbine engine as recited in claim 7, wherein a ratio of the hub diameter to the inlet diameter is between 0.63 and 0.94. ### Claim 9 (depends on 8) The gas turbine engine as recited in claim 8, including a forward bearing assembly spaced an axial distance from the outlet to the compressor and an overall distance from a forward part of the fan hub and a ratio of the overall distance relative to the axial distance between the forward bearing assembly and the outlet to the compressor is between 4.3 and 17.5. ### Claim 10 (depends on 8) The gas turbine engine as recited in claim 8, including a forward bearing assembly disposed at a diameter and a ratio of the outlet diameter of the outlet to the compressor to the forward bearing assembly diameter is between 1.95 and 2.92. ### Claim 11 (depends on 1) The gas turbine engine as recited in claim 1, wherein the geared architecture comprises an epicyclic gear system including a ring gear circumscribing a plurality of planetary gears driven by a sun gear and a carrier supporting the planetary gears and the gear volume is defined within a space bounded by the ring gear and outer periphery of the carrier. ### Claim 12 (depends on 1) The gas turbine engine as recited in claim 1, wherein the gas turbine engine is sized to generate thrust ranging between 12,500 lbf and 17,500 lbf. ### Claim 13 (depends on 1) The gas turbine engine as recited in claim 1, wherein the turbine section includes a two stage high pressure turbine and a low pressure turbine coupled to drive the geared architecture. ### Claim 14 (depends on 13) The gas turbine engine as recited in claim 13, wherein the low pressure turbine includes between three and six turbine rotors. ### Claim 15 A front section of a gas turbine engine comprising a propulsor section; a geared architecture driven by a turbine section for rotating the propulsor section about an axis, wherein the geared architecture comprises an epicyclic gear system including a ring gear circumscribing a plurality of planetary gears driven by a sun gear and a carrier supporting the planetary gears and a gear volume is defined within a space bounded by the ring gear and an outer periphery of the carrier and is between 526 in3 and 790 in3; and a compressor entrance passage disposed around the geared architecture including an inlet disposed at an inlet diameter and an outlet disposed at an outlet diameter, wherein a ratio of the inlet diameter to the outlet diameter is between 1.22 and 1.82. ### Claim 16 (depends on 15) The front section as recited in claim 15, wherein the geared architecture includes an outer diameter less than the outlet diameter. ### Claim 17 (depends on 16) The front section as recited in claim 16, wherein a geared architecture power transfer parameter (PTP) is defined as power transferred through the geared architecture divided by the gear volume multiplied by a gear reduction ratio and is between about 219 and 328. ### Claim 18 (depends on 17) The front section as recited in claim 17, including a forward bearing assembly disposed at a diameter and a ratio of the outlet diameter to the bearing assembly diameter is between 1.95 and 2.92. ### Claim 19 (depends on 18) The front section as recited in claim 18, including an overall axial length between a forward portion of the propulsor section and a forward bearing assembly, wherein the geared architecture includes an axial length and a ratio of the overall length to the axial length of the geared architecture is between 6 and 18.