# US 10,480,341 B2 · Run-in coating for an outer air seal of a turbomachine > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,480,341 B2 - Document ID: US10480341B2 - Status: Granted - Kind: B2 - Application number: 15/364,601 - Filed: 2016-11-30 - Published: 2017-06-08 - Granted: 2019-11-19 - Earliest claimed: 2015-12-03 - Assignees: MTU Aero Engines AG - Applicants: MTU Aero Engines AG - Inventors: Petra Kufner; Walter Gieg; Rudolf Stanka; René Schneider; Norman Cleesattel; Joachim Lorenz - Web page: https://patentgrep.com/patent/US10480341B2 ## CPC - F01D 11/127: {with a deformable or crushable structure, e.g. honeycomb} - F01D 5/02: Blade-carrying members, e.g. rotors (rotors of non-bladed type F01D1/34; stators F01D9/00 {; selecting particular materials F01D5/28}) - F01D 25/005: {Selecting particular materials} - F05D 2220/323: for aircraft propulsion, e.g. jet engines - F05D 2230/10: by removing material - F05D 2230/90: Coating; Surface treatment - F05D 2240/11: Shroud seal segments - F05D 2250/283: honeycomb - 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) - F05D: INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS - Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION ## Abstract The invention relates to a run-in coating (10) for an outer air seal of a turbomachine, especially of an aero engine, comprising a substrate (12) of segmented form which carries a honeycomb structure (14) with an run-in surface (15) to face rotor blades of a rotor of the turbomachine, wherein a radial thickness of the honeycomb structure (14) varies in the circumferential direction. The invention furthermore relates to an outer air seal for a turbomachine and also to a turbomachine with an outer air seal. ## Claims ### Claim 1 A run-in coating for an outer air seal of a turbomachine, wherein the run-in coating comprises a substrate of segmented form which carries a honeycomb structure with a run-in surface to face rotor blades of a rotor of the turbomachine, and wherein a radial thickness of the honeycomb structure varies in circumferential direction. ### Claim 2 (depends on 1) The run-in coating of claim 1, wherein the substrate is of circular segmented form. ### Claim 3 (depends on 1) The run-in coating of claim 1, wherein the substrate has a radial thickness in circumferential direction which is at least substantially constant. ### Claim 4 (depends on 2) The run-in coating of claim 2, wherein the substrate has a radial thickness in circumferential direction which is at least substantially constant. ### Claim 5 (depends on 1) The run-in coating of claim 1, wherein the run-in coating is designed in such a way that in an intended installed position of the run-in coating in the turbomachine a radial distance of the run-in surface to a machine axis of the turbomachine does not change in axial direction. ### Claim 6 (depends on 1) The run-in coating of claim 1, wherein the run-in coating is designed in such a way that in an intended installed position of the run-in coating in the turbomachine a run-in surface of the run-in coating has a radial step. ### Claim 7 (depends on 1) The run-in coating of claim 1, wherein the run-in coating comprises a middle region which is arranged between a first end region and a second end region as seen in circumferential direction, the first and the second end regions having a larger radial thickness than the middle region. ### Claim 8 (depends on 7) The run-in coating of claim 7, wherein the radial thickness of the run-in coating in the middle region is at most 99.5% of the radial thickness of the run-in coating in the first and/or second end regions. ### Claim 9 (depends on 7) The run-in coating of claim 7, wherein the radial thickness of the run-in coating decreases monotonically from the first end region to the middle region and/or from the second end region to the middle region in circumferential direction. ### Claim 10 (depends on 8) The run-in coating of claim 8, wherein the radial thickness of the run-in coating decreases monotonically from the first end region to the middle region and/or from the second end region to the middle region in circumferential direction. ### Claim 11 (depends on 7) The run-in coating of claim 7, wherein the radial thickness of the run-in coating decreases strictly monotonically from the first end region to the middle region and/or from the second end region to the middle region in circumferential direction. ### Claim 12 (depends on 1) A method for producing the run-in coating of claim 1, wherein the method comprises providing a run-in coating with a substrate which carries a honeycomb structure with a run-in surface of circular segmented form to face rotor blades of a rotor of the turbomachine, and is contoured in circumferential direction so that a radial thickness of the honeycomb structure varies in the circumferential direction. ### Claim 13 (depends on 12) The method of claim 12, wherein for contouring, the honeycomb structure is subjected to a separation process at least in areas. ### Claim 14 (depends on 12) The method of claim 12, wherein the separation process comprises grinding. ### Claim 15 (depends on 1) An outer air seal for a turbomachine, wherein the seal comprises a plurality of run-in coatings arranged in a ring-like manner, at least one of the plurality of run-in coatings being a run-in coating according to claim 1. ### Claim 16 (depends on 15) A turbomachine, wherein the turbomachine comprises the outer air seal of claim 15. ### Claim 17 (depends on 1) A turbomachine, wherein the turbomachine comprises a casing and a rotor which is arranged in the casing and can rotate around a rotational axis, and wherein an outer air seal which comprises a plurality of run-in coatings arranged in a ring-like manner, is arranged between the casing and rotor blades of the rotor, at least one of the plurality of run-in coatings being a run-in coating according to claim 1. ### Claim 18 (depends on 16) The turbomachine of claim 16, wherein the turbomachine is an aero engine. ### Claim 19 (depends on 17) The turbomachine of claim 17, wherein the turbomachine is an aero engine.