# US 12,601,282 B2 · Turbofan gas turbine engine with inner ring reinforcing structure and methods of producing the same > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,601,282 B2 - Document ID: US12601282B2 - Status: Granted - Kind: B2 - Application number: 18/603,384 - Filed: 2024-03-13 - Published: 2025-07-31 - Granted: 2026-04-14 - Earliest claimed: 2024-01-30 - Assignees: Honeywell International Inc. - Applicants: Honeywell International Inc. - Inventors: Avinash Kumar; Tirumala Koka; Milind Khare - Web page: https://patentgrep.com/patent/US12601282B2 ## CPC - F01D 25/26: Double casings; Measures against temperature strain in casings - F01D 21/045: {special arrangements in stators or in rotors dealing with breaking-off of part of rotor} - F05D 2220/32: in gas turbines - F05D 2230/60: Assembly methods - F05D 2240/14: Casings or housings protecting or supporting assemblies within - F01D: NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES (machines or engines for liquids F03; non-positive displacement pumps F04D) - F05D: INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS ## Abstract Turbofan gas turbine engines and methods are provided. The engines include a fan assembly having an engine rotor hub with fan blades extending radially therefrom configured for rotation of the fan blades, a fan housing structure encircling the fan assembly and including an inner ring that defines an exposed inner surface of the fan housing structure that includes a radially protruding section that defines a recess facing the fan blades and encircling tips thereof, a fan containment structure within the fan housing structure positioned circumferentially around the fan assembly and axially encircling the radially protruding section, and a reinforcing structure fixed to or integrated with an annular portion of the inner ring that is configured to provide greater impact resistance to the forward end of the radially protruding section relative to an aft end thereof. ## Claims ### Claim 1 A turbofan gas turbine engine, comprising: a fan assembly that includes an engine rotor hub with fan blades extending radially therefrom, the fan assembly configured for rotation of the fan blades about an axis of rotation; a fan housing structure encircling the fan assembly and including an inner ring that defines an exposed inner surface of the fan housing structure facing the fan blades of the fan assembly, wherein the inner ring includes a radially protruding section that defines a recess on the exposed inner surface thereof encircling tips of the fan blades; a fan containment structure within the fan housing structure positioned circumferentially around the fan assembly and axially encircling the radially protruding section; and a reinforcing structure fixed to or integrated with an annular portion of the inner ring and disposed at a forward end of the radially protruding section, wherein the reinforcing structure is positioned to be axially encircled by the fan containment structure and forward of the tips of the fan blades, wherein the reinforcing structure is configured to provide greater impact resistance to the forward end of the radially protruding section relative to an aft end of the radially protruding section that is not in contact with the reinforcing structure. ### Claim 2 (depends on 1) The turbofan gas turbine engine of claim 1, wherein the reinforcing structure is configured to reduce forward axial motion of an object that impacts the reinforcing structure. ### Claim 3 (depends on 1) The turbofan gas turbine engine of claim 1, wherein the reinforcing structure defines an S-shaped surface at the forward end of the radially protruding section. ### Claim 4 (depends on 1) The turbofan gas turbine engine of claim 1, wherein the reinforcing structure includes a first portion extending axially along the inner ring and having a first end contacting the fan containment structure at a first point and a second end contacting the forward end of the radially protruding section, and a second portion extending radially from the inner ring and coupled to the second end of the first portion and extending therefrom to contact the fan containment structure at a second point. ### Claim 5 (depends on 1) The turbofan gas turbine engine of claim 1, wherein an abradable material is disposed within the recess of the radially protruding section, wherein the reinforcing structure is positioned within the recess adjacent to the forward end of the radially protruding section. ### Claim 6 (depends on 1) The turbofan gas turbine engine of claim 1, wherein the reinforcing structure includes two or more layers of a composite material fixed to or integrated with the inner ring. ### Claim 7 (depends on 1) The turbofan gas turbine engine of claim 1, wherein the inner ring of the fan housing structure is formed of a metallic material. ### Claim 8 (depends on 1) The turbofan gas turbine engine of claim 1, wherein the inner ring of the fan housing structure is formed of a composite material. ### Claim 9 (depends on 1) The turbofan gas turbine engine of claim 1, wherein the inner ring of the fan housing structure includes at least a first layer and a second layer, and the reinforcing structure is disposed between the first layer and the second layer of the inner ring. ### Claim 10 (depends on 1) The turbofan gas turbine engine of claim 1, wherein a first diameter of the forward end of the radially protruding section is greater than a second diameter of the aft end of the radially protruding section. ### Claim 11 (depends on 1) The turbofan gas turbine engine of claim 1, wherein a leading edge of each of the fan blades extends further radially from the axis of rotation than a trailing edge of each of the fan blades. ### Claim 12 (depends on 1) The turbofan gas turbine engine of claim 1, wherein the fan assembly is a blisk fan assembly. ### Claim 13 (depends on 1) The turbofan gas turbine engine of claim 1, wherein the fan assembly is an inserted disk fan assembly. ### Claim 14 A method of producing a turbofan gas turbine engine, comprising: assembling a fan assembly that includes an engine rotor hub with fan blades extending radially therefrom, the fan assembly configured for rotation of the fan blades about an axis of rotation; assembling a fan housing structure encircling the fan assembly and including an inner ring that defines an exposed inner surface of the fan housing structure facing the fan blades of the fan assembly, wherein the inner ring includes a radially protruding section that defines a recess on the exposed inner surface thereof encircling tips of the fan blades; securing a fan containment structure within the fan housing structure positioned circumferentially around the fan assembly and axially encircling the radially protruding section; and promoting greater impact resistance to a forward end of the radially protruding section relative to an aft end of the radially protruding section by disposing a reinforcing structure at the forward end of the radially protruding section, wherein the reinforcing structure is fixed to or integrated with an annular portion of the inner ring, positioned to be axially encircled by the fan containment structure, and positioned forward of the tips of the fan blades. ### Claim 15 (depends on 14) The method of claim 14, further comprising configuring the reinforcing structure to reduce forward axial motion of an object that impacts the reinforcing structure. ### Claim 16 (depends on 14) The method of claim 14, further comprising configuring the reinforcing structure to define an S-shaped surface at the forward end of the radially protruding section. ### Claim 17 (depends on 14) The method of claim 14, further comprising disposing an abradable material within the recess of the radially protruding section, wherein the reinforcing structure is positioned within the recess adjacent to the forward end of the radially protruding section. ### Claim 18 (depends on 14) The method of claim 14, further comprising: forming a first layer of the inner ring of the fan housing structure; disposing the reinforcing structure on the first layer of the inner ring; and forming a second layer of the inner ring on the reinforcing structure. ### Claim 19 (depends on 14) The method of claim 14, wherein the fan assembly is assembled as a blisk fan assembly. ### Claim 20 (depends on 14) The method of claim 14, wherein the fan assembly is assembled as an inserted disk fan assembly.