# US 11,078,951 B2 · Locking assembly for rotatable components > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,078,951 B2 - Document ID: US11078951B2 - Status: Granted - Kind: B2 - Application number: 16/416,830 - Filed: 2019-05-20 - Published: 2020-11-26 - Granted: 2021-08-03 - Earliest claimed: 2019-05-20 - Assignees: Hamilton Sundstrand Corporation - Applicants: Hamilton Sundstrand Corporation - Inventors: Yiwei Jiang; Michael R. Blewett; Edward W. Goy - Web page: https://patentgrep.com/patent/US11078951B2 ## CPC - F16B 39/16: in which the screw-thread of the locknut differs from that of the nut - F16D 1/108: having retaining means rotating with the coupling and acting by interengaging parts, i.e. positive coupling - F01D 25/28: Supporting or mounting arrangements, e.g. for turbine casing - F02C 7/277: the starter being a {separate} turbine - F02C 7/36: Power transmission arrangements between the different shafts of the gas turbine plant, or between the gas-turbine plant and the power user ({F02C3/107 - F02C3/13 and} F02C7/32 take precedence; couplings for transmitting rotation F16D; gearing in general F16H) - F16B 41/002: {Measures against loss of bolts, nuts or pins (devices for fastening nuts to surfaces F16B37/04)} - F05D 2260/30: Retaining components in desired mutual position - F16D 2001/103: {the torque is transmitted via splined connections} - F16B: DEVICES FOR FASTENING OR SECURING CONSTRUCTIONAL ELEMENTS OR MACHINE PARTS TOGETHER, e.g. NAILS, BOLTS, CIRCLIPS, CLAMPS, CLIPS OR WEDGES; JOINTS OR JOINTING (couplings for transmitting rotation F16D) - F16D: COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES - F01D: NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES (machines or engines for liquids F03; non-positive displacement pumps F04D) - F02C: GAS-TURBINE PLANTS; AIR INTAKES FOR JET-PROPULSION PLANTS; CONTROLLING FUEL SUPPLY IN AIR-BREATHING JET-PROPULSION PLANTS (construction of turbines F01D; jet-propulsion plants F02K; construction of compressors or fans F04; generating combustion products of high pressure or high velocity F23R; using gas turbines in compression refrigeration plants F25B11/00) - F05D: INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS ## Abstract An assembly for a coupling together rotatable components according to an example of the present disclosure includes, among other things, a rotor shaft extending along a centerline axis, the rotor shaft defining an inner bore extending from an axial end of the rotor shaft, a gear mounted on an outer diameter of the rotor shaft, a lock nut threadedly engaged with the outer diameter of the rotor shaft such that the lock nut abuts against an axial end face of the gear, and a retainer including a step portion extending from a head portion and including a projection portion extending from the step portion. The projection portion is insertable into the inner bore to bias the lock nut against the axial end face of the gear, and the step portion is dimensioned to establish an interference fit with the rotor shaft along the inner bore. A starter assembly and a method of assembly are also disclosed. ## Claims ### Claim 1 An assembly for a coupling together rotatable components comprising: a rotor shaft extending along a centerline axis, the rotor shaft defining an inner bore extending from an axial end of the rotor shaft; a gear mounted on an outer diameter of the rotor shaft; a lock nut threadedly engaged with the outer diameter of the rotor shaft such that the lock nut abuts against an axial end face of the gear; and a retainer including a step portion extending from a head portion and including a projection portion extending from the step portion, wherein the projection portion is insertable into the inner bore to bias the lock nut against the axial end face of the gear, and the step portion is dimensioned to establish an interference fit with the rotor shaft along the inner bore. ### Claim 2 (depends on 1) The assembly as set forth in claim 1, wherein the inner bore is a counterbore including a first portion having a greater diameter than a second portion, and the first portion is dimensioned to establish the interference fit. ### Claim 3 (depends on 2) The assembly as set forth in claim 2, wherein the projection portion is threadedly engaged with the rotor shaft along the second portion of the counterbore. ### Claim 4 (depends on 3) The assembly as set forth in claim 3, wherein the projection portion is threadedly engaged with the rotor shaft along the second portion of the counterbore through a threaded helicoil insert. ### Claim 5 (depends on 3) The assembly as set forth in claim 3, wherein the lock nut is threadedly engaged with the outer diameter of the rotor shaft in a first threaded direction, and the projection portion is threadedly engaged with the rotor shaft along the second portion of the counterbore in a second threaded direction opposite the first threaded direction. ### Claim 6 (depends on 1) The assembly as recited in claim 1, wherein the projection portion of the retainer is directly threadedly engaged with the rotor shaft along the inner bore. ### Claim 7 (depends on 1) The assembly as set forth in claim 1, wherein the gear is a sun gear that meshes with a plurality of intermediate gears of an epicyclic gear system comprising the sun gear. ### Claim 8 (depends on 1) The assembly as set forth in claim 1, wherein an inner diameter of the gear includes a first set of splines that engage with a second set of splines along the outer diameter of the rotor shaft to establish a splined interface. ### Claim 9 (depends on 1) The assembly as set forth in claim 1, further comprising a bearing assembly mounted on the outer diameter of the rotor shaft such that the gear is sandwiched between the bearing assembly and the lock nut. ### Claim 10 (depends on 1) The assembly as set forth in claim 1, further comprising a spacer sandwiched between the lock nut and the head portion of the retainer. ### Claim 11 A starter assembly for a gas turbine engine comprising: a rotor shaft extending along a centerline axis, the rotor shaft defining a counterbore including a first portion having a greater diameter than a second portion; a turbine rotor rotatable with the rotor shaft; an epicyclic gear system including a sun gear, a plurality of intermediate gears and a ring gear, wherein the sun gear is mounted on an outer diameter of the rotor shaft, the plurality of intermediate gears mesh with the sun gear and the ring gear, and the epicyclic gear system interconnects the rotor shaft and an output shaft; a bearing assembly received on the rotor shaft axially between the sun gear and the turbine rotor relative to the centerline axis; a lock nut threadedly engaged with the outer diameter of the rotor shaft; and a retainer including a step portion extending from a head portion and including a projection portion extending from the step portion, wherein the step portion is dimensioned to establish an interference fit with the rotor shaft along the first portion of the counterbore, and the projection portion is threadedly engaged with the rotor shaft along the second portion of the counterbore such that the lock nut is biased against an axial end face of the sun gear. ### Claim 12 (depends on 11) The starter assembly as set forth in claim 11, wherein the output shaft drives an accessory gearbox in response to rotation of the rotor shaft. ### Claim 13 (depends on 12) The starter assembly as set forth in claim 12, wherein the ring gear drives the output shaft in response to rotation of the rotor shaft. ### Claim 14 (depends on 11) The starter assembly as set forth in claim 11, wherein the epicyclic gear system drives the output shaft through a clutch. ### Claim 15 A method of assembly for coupling together components of a starter assembly for a gas turbine engine comprising: mounting a gear on an outer diameter of a rotor shaft, the rotor shaft defining an inner bore extending from an axial end of the rotor shaft; fastening a lock nut onto the outer diameter of the rotor shaft such that the lock nut abuts against an axial end face of the gear; and fastening a retainer to the rotor shaft to bias the lock nut against the axial end face of the gear, including threadedly engaging a projection portion of the retainer in the inner bore such that a step portion of the retainer is moved along a centerline axis of the rotor shaft to establish an interference fit with the rotor shaft along the inner bore. ### Claim 16 (depends on 15) The method as set forth in claim 15, wherein the gear is a sun gear that meshes with a plurality of intermediate gears of an epicyclic gear system comprising the sun gear. ### Claim 17 (depends on 16) The method as set forth in claim 16, further comprising: coupling the rotor shaft to a turbine rotor; and coupling the epicyclic gear system to an accessory gearbox to drive a gas turbine engine. ### Claim 18 (depends on 15) The method as set forth in claim 15, wherein the lock nut is threadedly engaged with the outer diameter of the rotor shaft in a first threaded direction, and the projection portion of the retainer is threadedly engaged with the rotor shaft along the inner bore in a second threaded direction opposite the first threaded direction. ### Claim 19 (depends on 15) The method as set forth in claim 15, wherein the step of threadedly engaging the projection portion includes positioning a threaded helicoil insert between threads along the projection portion and threads along the inner bore. ### Claim 20 (depends on 15) The method as set forth in claim 15, further comprising positioning a spacer on the outer diameter of the rotor shaft such that a head portion of the retainer biases the spacer against the lock nut in response to the step of threadedly engaging the projection portion of the retainer in the inner bore.