# US 11,306,772 B2 · Radial foil bearing > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,306,772 B2 - Document ID: US11306772B2 - Status: Granted - Kind: B2 - Application number: 17/011,269 - Filed: 2020-09-03 - Published: 2021-01-14 - Granted: 2022-04-19 - Earliest claimed: 2018-03-07 - Assignees: IHI Corporation - Applicants: Ihi Corporation - Inventors: Naomichi Omori - Web page: https://patentgrep.com/patent/US11306772B2 ## CPC - F16C 17/024: {with flexible leaves to create hydrodynamic wedge, e.g. radial foil bearings} - F16C 27/02: Sliding-contact bearings - F16C 33/08: Attachment of brasses, bushes or linings to the bearing housing - F16C 2360/24: Turbochargers - F16C: SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS ## Abstract A radial foil bearing includes a bearing housing that has an insertion hole into which a shaft is inserted, a back foil that is disposed on an inner peripheral surface of the insertion hole, a top foil that is supported by the back foil, and a protrusion portion that protrudes toward an inner side in a radial direction of the insertion hole from the inner peripheral surface of the insertion hole and is configured to allow supporting of the top foil. ## Claims ### Claim 1 A radial foil bearing comprising: a bearing housing that has an insertion hole into which a shaft is to be inserted; a back foil that is disposed on an inner peripheral surface of the insertion hole; a top foil that is supported by the back foil; and a protrusion portion that protrudes toward an inner side in a radial direction of the insertion hole from the inner peripheral surface of the insertion hole and is configured to allow supporting of the top foil in the radial direction of the insertion hole, wherein the back foil includes four end edges that extend in a direction intersecting an axial direction of the insertion hole with the protrusion portion interposed therebetween, and the protrusion portion and the bearing housing are formed of one-piece. ### Claim 2 (depends on 1) The radial foil bearing according to claim 1, wherein the back foil includes a hole portion to which the protrusion portion is fitted. ### Claim 3 (depends on 2) The radial foil bearing according to claim 2, wherein the protrusion portion includes a top wall portion at a position in the axial direction within a range of ±5% from a middle position in the axial direction of the insertion hole. ### Claim 4 (depends on 3) The radial foil bearing according to claim 3, wherein the protrusion portion is formed in a ring shape along a circumferential direction of the inner peripheral surface of the insertion hole. ### Claim 5 (depends on 3) The radial foil bearing according to claim 3, wherein a plurality of the protrusion portions are formed with a gap along a circumferential direction of the inner peripheral surface of the insertion hole. ### Claim 6 (depends on 2) The radial foil bearing according to claim 2, wherein the protrusion portion is formed in a ring shape along a circumferential direction of the inner peripheral surface of the insertion hole. ### Claim 7 (depends on 2) The radial foil bearing according to claim 2, wherein a plurality of the protrusion portions are formed with a gap along a circumferential direction of the inner peripheral surface of the insertion hole. ### Claim 8 (depends on 1) The radial foil bearing according to claim 1, wherein the protrusion portion includes a top wall portion at a position in the axial direction within a range of ±5% from a middle position in the axial direction of the insertion hole. ### Claim 9 (depends on 8) The radial foil bearing according to claim 8, wherein the protrusion portion is formed in a ring shape along a circumferential direction of the inner peripheral surface of the insertion hole. ### Claim 10 (depends on 8) The radial foil bearing according to claim 8, wherein a plurality of the protrusion portions are formed with a gap along a circumferential direction of the inner peripheral surface of the insertion hole. ### Claim 11 (depends on 8) The radial foil bearing according to claim 8, wherein the back foil includes a first back foil and a second back foil, which are separated in the axial direction of the insertion hole, and the first back foil and the second back foil face each other in the axial direction with the protrusion portion interposed therebetween. ### Claim 12 (depends on 1) The radial foil bearing according to claim 1, wherein the protrusion portion is formed in a ring shape along a circumferential direction of the inner peripheral surface of the insertion hole. ### Claim 13 (depends on 12) The radial foil bearing according to claim 12, wherein the back foil includes a first back foil and a second back foil, which are separated in the axial direction of the insertion hole, and the first back foil and the second back foil face each other in the axial direction with the protrusion portion interposed therebetween. ### Claim 14 (depends on 1) The radial foil bearing according to claim 1, wherein a plurality of the protrusion portions are formed with a gap along a circumferential direction of the inner peripheral surface of the insertion hole. ### Claim 15 (depends on 14) The radial foil bearing according to claim 14, wherein the back foil includes a first support portion that is disposed on a first side in the axial direction with respect to the protrusion portions, a second support portion that is disposed on a second side in the axial direction with respect to the protrusion portions, and a connecting portion that is disposed in the gap and connects the first support portion and the second support portion to each other. ### Claim 16 (depends on 1) The radial foil bearing according to claim 1, wherein the back foil includes a first back foil and a second back foil, which are separated in the axial direction of the insertion hole, and the first back foil and the second back foil face each other in the axial direction with the protrusion portion interposed therebetween. ### Claim 17 (depends on 16) The radial foil bearing according to claim 16, wherein the first back foil and the second back foil have different support stiffness for supporting the top foil.