# US 10,479,497 B2 · Inboard bearing assemblies having load transfer shoe bolts > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,479,497 B2 - Document ID: US10479497B2 - Status: Granted - Kind: B2 - Application number: 15/990,624 - Filed: 2018-05-26 - Published: 2019-01-17 - Granted: 2019-11-19 - Earliest claimed: 2017-07-13 - Assignees: Bell Textron Inc. - Applicants: Bell Helicopter Textron Inc. - Inventors: Robert Patrick Wardlaw; John Richard McCullough; Amarjit Olenchery Kizhakkepat; Tyler Wayne Baldwin - Web page: https://patentgrep.com/patent/US10479497B2 ## CPC - B64C 29/0033: {the propellers being tiltable relative to the fuselage} - B64C 11/06: for variable-pitch blades - B64C 27/35: having elastomeric joints - F16C 17/10: for both radial and axial load - F16C 33/06: Sliding surface mainly made of metal (F16C33/24 - F16C33/28 take precedence; {casting metal bearing surfaces B22D15/02, B22D19/08}) - F16C 2326/43: Aeroplanes; Helicopters - B64C: AEROPLANES; HELICOPTERS - F16C: SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS ## Abstract A proprotor system for a tiltrotor aircraft having helicopter and airplane flight modes includes a yoke having a plurality of blade arms each having an inboard pocket with an outboard surface. Each of a plurality of bearing assemblies is disposed at least partially within one of the inboard pockets with each bearing assembly including a shear bearing and a centrifugal force bearing having an integral shoe with an outboard surface. Each of a plurality of inboard beams is disposed at least partially between one of the centrifugal force bearings and one of the shear bearings. Each of a plurality of proprotor blades is coupled to one of the inboard beams. The integral shoes are coupled to the yoke such that there is a spaced apart relationship between the outboard surfaces of the integral shoes and the outboard surfaces of the pockets to prevent centrifugal force load transfer therebetween. ## Claims ### Claim 1 A proprotor system for a tiltrotor aircraft having a helicopter flight mode and an airplane flight mode, the proprotor system comprising: a yoke having a plurality of blade arms including a first blade arm having an inboard pocket with an outboard surface; a bearing assembly disposed at least partially within the inboard pocket, the bearing assembly including a shear bearing and a centrifugal force bearing having an integral shoe with an outboard surface; an inboard beam disposed at least partially between the centrifugal force bearing and the shear bearing; and a proprotor blade coupled to the inboard beam; wherein, the integral shoe is coupled to the yoke such that there is a spaced apart relationship between the outboard surface of the integral shoe and the outboard surface of the pocket forming a gap therebetween that prevents centrifugal force load transfer therebetween. ### Claim 2 (depends on 1) The proprotor system as recited in claim 1 wherein the yoke further comprises first and second surfaces and defines a plurality of shoe bolt openings extending between the first and second surfaces outboard of the inboard pocket. ### Claim 3 (depends on 2) The proprotor system as recited in claim 2 further comprising a bushing disposed within each of the shoe bolt openings of the yoke. ### Claim 4 (depends on 2) The proprotor system as recited in claim 2 wherein the integral shoe further comprises first and second clamp plates each having a plurality of shoe bolt openings. ### Claim 5 (depends on 4) The proprotor system as recited in claim 4 wherein the second clamp plate of the integral shoe is independent of the centrifugal force bearing and selectively coupled thereto. ### Claim 6 (depends on 4) The proprotor system as recited in claim 4 wherein the first clamp plate and the second clamp plate each has two shoe bolt openings. ### Claim 7 (depends on 4) The proprotor system as recited in claim 4 wherein the first clamp plate and the second clamp plate each has three shoe bolt openings. ### Claim 8 (depends on 4) The proprotor system as recited in claim 4 wherein the first clamp plate and the second clamp plate each has four shoe bolt openings. ### Claim 9 (depends on 4) The proprotor system as recited in claim 4 further comprising a plurality of shoe bolts each passing through aligned shoe bolt openings of the first and second clamp plates and the yoke to clamp the integral shoe to the yoke creating the spaced apart relationship between the outboard surface of the integral shoe and the outboard surface of the inboard pocket to prevent centrifugal force load transfer therebetween. ### Claim 10 (depends on 9) The proprotor system as recited in claim 9 wherein the shoe bolts provide centrifugal force load paths between the bearing assembly and the yoke. ### Claim 11 (depends on 9) The proprotor system as recited in claim 9 wherein the first clamp plate of the integral shoe has a contact relationship with the first surface of the yoke and the second clamp plate of the integral shoe has a contact relationship with the second surface of the yoke. ### Claim 12 (depends on 1) The proprotor system as recited in claim 1 wherein the centrifugal force bearing further comprises an elastomeric element that is vulcanized with the integral shoe. ### Claim 13 (depends on 1) The proprotor system as recited in claim 1 wherein, the centrifugal force bearing is positioned outboard of the shear bearing. ### Claim 14 A proprotor system for a tiltrotor aircraft having a helicopter flight mode and an airplane flight mode, the proprotor system comprising: a yoke having a plurality of blade arms including a first blade arm having an inboard pocket with an outboard surface; a bearing assembly disposed at least partially within the inboard pocket, the bearing assembly including a shear bearing and a centrifugal force bearing having an integral shoe with an outboard surface; an inboard beam disposed at least partially between the centrifugal force bearing and the shear bearing; a proprotor blade coupled to the inboard beam; and a plurality of shoe bolts coupling the integral shoe to the yoke such that the shoe bolts provide centrifugal force load paths between the bearing assembly and the yoke and such that there is a spaced apart relationship between the outboard surface of the integral shoe and the outboard surface of the inboard pocket forming a gap therebetween that prevents centrifugal force load transfer therebetween. ### Claim 15 (depends on 14) The proprotor system as recited in claim 14 wherein the yoke further comprises first and second surfaces and defines a plurality of shoe bolt openings extending between the first and second surfaces outboard of the inboard pocket. ### Claim 16 (depends on 15) The proprotor system as recited in claim 15 wherein the integral shoe further comprises first and second clamp plates each having a plurality of shoe bolt openings. ### Claim 17 (depends on 16) The proprotor system as recited in claim 16 wherein the second clamp plate of the integral shoe is independent of the centrifugal force bearing and selectively coupled thereto. ### Claim 18 (depends on 16) The proprotor system as recited in claim 16 wherein each of the shoe bolts passes through aligned shoe bolt openings of the first and second clamp plates and the yoke to clamp the integral shoe to the yoke creating the spaced apart relationship between the outboard surface of the integral shoe and the outboard surface of the inboard pocket to prevent centrifugal force load transfer therebetween. ### Claim 19 (depends on 14) The proprotor system as recited in claim 14 wherein the centrifugal force bearing further comprises an elastomeric element that is vulcanized with the integral shoe. ### Claim 20 A tiltrotor aircraft having a helicopter flight mode and an airplane flight mode, the tiltrotor aircraft comprising: a fuselage; a wing extending from the fuselage; first and second pylon assemblies coupled to the wing outboard of the fuselage; and first and second proprotor systems operably associated respectively with the first and second pylon assemblies, each proprotor system including: a yoke having a plurality of blade arms including a first blade arm having an inboard pocket with an outboard surface; a bearing assembly disposed at least partially within the inboard pocket, the bearing assembly including a shear bearing and a centrifugal force bearing having an integral shoe with an outboard surface; an inboard beam disposed at least partially between the centrifugal force bearing and the shear bearing; and a proprotor blade coupled to the inboard beam; wherein the integral shoe is coupled to the yoke such that there is a spaced apart relationship between the outboard surface of the integral shoe and the outboard surface of the pocket forming a gap therebetween that prevents centrifugal force load transfer therebetween.