# US 11,306,616 B2 · Mechanical arrangement for joining engine components > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,306,616 B2 - Document ID: US11306616B2 - Status: Granted - Kind: B2 - Application number: 16/744,531 - Filed: 2020-01-16 - Published: 2021-07-22 - Granted: 2022-04-19 - Earliest claimed: 2020-01-16 - Assignees: Pratt & Whitney Canada Corp. - Applicants: Pratt & Whitney Canada Corp. - Inventors: Guy Lefebvre; Francois Doyon; Remy Synnott - Web page: https://patentgrep.com/patent/US11306616B2 ## CPC - F01D 25/243: {Flange connections; Bolting arrangements (F01D25/265 takes precedence)} - F01D 25/30: Exhaust heads, chambers, or the like - F05D 2230/232: by welding - F05D 2230/60: Assembly methods - F05D 2240/50: Bearings - 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 A turbine exhaust case assembly has an exhaust case and a bearing housing mounted in the exhaust case. A plurality of fasteners secures the bearing housing to the exhaust case. A spacer is mounted between the fasteners and one of the bearing housing and the exhaust case. The fasteners are welded to the spacer, thereby locking the fasteners against rotation. ## Claims ### Claim 1 A turbine exhaust case assembly comprising: an exhaust case extending circumferentially around a central axis, the exhaust case including a plurality of circumferentially spaced-apart struts; a bearing housing mounted in the exhaust case; at least one service tube extending radially through one of said plurality of circumferentially spaced-apart struts, the at least one service tube having a radially inner end brazed to the bearing housing; a plurality of fasteners securing the bearing housing to the exhaust case; a sacrificial part mounted between the plurality of fasteners and one of the bearing housing and the exhaust case; and at least one weld between the plurality of the fasteners and the sacrificial part, the at least one weld locking the fasteners against rotation. ### Claim 2 (depends on 1) The turbine exhaust case assembly according to claim 1, wherein the sacrificial part includes a spacer ring defining a plurality of bores in registry with corresponding bores defined in the exhaust case and the bearing housing for receiving said plurality of fasteners, and wherein the spacer is provided on an axially facing surface of the of the exhaust case opposite to the bearing housing. ### Claim 3 (depends on 2) The turbine exhaust case assembly according to claim 2, wherein the plurality of fasteners are tack welded to the spacer ring. ### Claim 4 (depends on 2) The turbine exhaust case assembly according to claim 2 further comprising a spigot joint between the exhaust case and the bearing housing, wherein the plurality of fasteners extends axially through the spigot joint, the plurality of fasteners including bolts each having a head and a shank extending from the head, the spacer being axially trapped between the head of each of the bolts and the exhaust case, and wherein the head of each of the bolts is directly welded to the spacer. ### Claim 5 (depends on 4) The turbine exhaust case assembly according to claim 4, wherein the bores defined in the exhaust case and the bearing housing extend through the spigot joint. ### Claim 6 (depends on 5) The turbine exhaust case assembly according to claim 5, wherein the spigot joint is a thigh fit spigot joint comprising an outer diameter surface on a radially inner flange of the exhaust case and an inner diameter surface on a radially outer flange of the bearing housing, the inner diameter surface on the radially outer flange mating with the outer diameter surface on the radially inner flange, and wherein the spigot joint further comprises an inner diameter surface on the radially inner flange of the exhaust case and an outer diameter surface on the radially outer flange of the bearing housing, the inner diameter surface on the radially inner flange mating with the outer diameter surface on the radially outer flange. ### Claim 7 A turbine exhaust case assembly comprising: an exhaust case extending circumferentially around a central axis, the exhaust case having a plurality of circumferentially spaced-apart struts and a radially inner flange having a plurality of through bores aligned on a plurality of fastener axes in a circumferentially spaced apart array; a bearing housing having a plurality of threaded bores aligned on the fastener axes; one or more service tubes extending radially through respective ones of the plurality of circumferentially spaced-apart struts, the one or more service tubes having a radially inner end brazed to the bearing housing; a plurality of fasteners, each fastener having a head engaging the exhaust case, a shank extending through the through bore, and a threaded end engaging the threaded bore for connecting and disconnecting the exhaust case and the bearing housing when the head is rotated; and an anti-rotation device securing the head of each fastener to the exhaust case, the anti-rotation device including at least one weld on the head of each one of the plurality of fasteners. ### Claim 8 (depends on 7) The turbine exhaust case assembly according to claim 7 wherein the anti-rotation device comprises a sacrificial part having a plurality of holes aligned on the fastener axes, the head of each one of the plurality of fasteners welded to the sacrificial part. ### Claim 9 (depends on 8) The turbine exhaust case assembly according to claim 8 wherein the sacrificial part includes a spacer ring welded to the head of each fastener. ### Claim 10 (depends on 7) The turbine exhaust case assembly according to claim 7 wherein a spigot joint is provided between the exhaust case and the bearing housing, the spigot joint including inner and outer diameter mating surfaces on both the exhaust case and the bearing housing. ### Claim 11 (depends on 8) The turbine exhaust case assembly according to claim 8 wherein the sacrificial part comprises a plurality of spacer ring segments, each spacer ring segment welded to at least two adjacent ones of the plurality of fasteners. ### Claim 12 A method for connecting an exhaust case and a bearing housing of a gas turbine engine, the method comprising: positioning the bearing housing in the exhaust case using spigot connection, inserting a service tube through a hollow strut of the exhaust case, brazing an inner end of the service tube to the exhaust case, fastening the bearing housing to the exhaust case using a plurality of threaded fasteners, and securing the plurality of threaded fasteners against rotation. ### Claim 13 (depends on 12) The method according to claim 12 comprising: before fastening, installing a sacrificial ring having a plurality of holes in registry with corresponding holes defined in the exhaust case and the bearing housing, and inserting the plurality of fasteners into the registering holes in the ring, the exhaust case and the bearing housing. ### Claim 14 (depends on 13) The method according to claim 13 comprising: wherein securing the plurality of threaded fasteners against rotation comprises welding the sacrificial ring to a head of each of the plurality of threaded fasteners. ### Claim 15 (depends on 14) The method according to claim 14 wherein the frangible connector comprises tack welds between the head of the threaded fasteners and the sacrificial ring. ### Claim 16 (depends on 12) The method according to claim 12 wherein positioning comprises press fitting the exhaust case and the bearing housing together. ### Claim 17 (depends on 14) The method according to claim 14, wherein brazing an inner end of the service tube to the exhaust case includes: temporarily maintaining the bearing housing and the exhaust case with a braze fixture to form a secured assembly, and placing the secured assembly in a braze furnace. ### Claim 18 (depends on 17) The method according to claim 17, further comprising removing the braze fixture prior to fastening the bearing housing to the exhaust case.