# US 2019/0245398 A1 · Electric machine rotor cooling systems and methods > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0245398 A1 - Document ID: US20190245398A1 - Status: Published application - Kind: A1 - Application number: 16/368,226 - Filed: 2019-03-28 - Published: 2019-08-08 - Earliest claimed: 2017-10-10 - Assignees: Zero E Technologies, LLC - Applicants: Zero E Technologies, LLC - Inventors: Thomas H. Hopkins; Felipe J. Castillo; Scott T. Graham; Keith W. Klontz - Web page: https://patentgrep.com/patent/US20190245398A1 ## CPC - H02K 1/32: with channels or ducts for flow of cooling medium - H02K 1/04: characterised by the material used for insulating the magnetic circuit or parts thereof - H02K 1/12: Stationary parts of the magnetic circuit - H02K 1/148: {Sectional cores (H02K1/141 takes precedence)} - H02K 1/18: Means for mounting or fastening magnetic stationary parts on to, or to, the stator structures - H02K 1/185: {to outer stators} - H02K 1/272: the magnetisation axis of the magnets being perpendicular to the rotor axis - H02K 1/278: Surface mounted magnets; Inset magnets - H02K 1/28: Means for mounting or fastening rotating magnetic parts on to, or to, the rotor structures - H02K 3/18: Windings for salient poles - H02K 3/30: Windings characterised by the insulating material - H02K 3/325: {for windings on salient poles, such as claw-shaped poles} - H02K 3/44: Protection against moisture or chemical attack; Windings specially adapted for operation in liquid or gas - H02K 3/522: {for generally annular cores with salient poles} - H02K 5/04: Casings or enclosures characterised by the shape, form or construction thereof - H02K 5/08: Insulating casings - H02K 5/15: Mounting arrangements for bearing-shields or end plates - H02K 5/1732: {radially supporting the rotary shaft at both ends of the rotor (H02K5/1737 takes precedence)} - H02K 5/18: with ribs or fins for improving heat transfer - H02K 5/24: specially adapted for suppression or reduction of noise or vibrations - H02K 7/003: {Couplings; Details of shafts (means for mounting rotors on shafts H02K1/28)} - H02K 7/083: {radially supporting the rotary shaft at both ends of the rotor (H02K7/086, H02K7/09 take precedence)} - H02K 9/06: with fans or impellers driven by the machine shaft - H02K 9/08: by gaseous cooling medium circulating wholly within the machine casing (H02K9/10 takes precedence) - H02K 9/19: for machines with closed casing and closed-circuit cooling using a liquid cooling medium, e.g. oil - H02K 9/22: by solid heat conducting material embedded in, or arranged in contact with, the stator or rotor, e.g. heat bridges - H02K 9/227: {Heat sinks} - H02K 11/25: Devices for sensing temperature, or actuated thereby - H02K 15/105: {to the windings} - H02K 15/121: of cores - H02K 15/122: of windings - H02K 15/14: Casings; Enclosures; Supports - H02K 5/06: Cast metal casings - H02K 2203/12: Machines characterised by the bobbins for supporting the windings - H02K: DYNAMO-ELECTRIC MACHINES (dynamo-electric relays H01H53/00; conversion of DC or AC input power into surge output power {H03K3/53}) ## Abstract An electric machine rotor including a shaft having a thermally conductive shaft core material having a different composition than a portion of the shaft surrounding the thermally conductive shaft core. The rotor also includes a rotor back assembly surrounding a portion of the shaft; and a plurality of permanent magnets radially positioned around the rotor back assembly. ## Claims ### Claim 1 An electric machine rotor comprising: a shaft comprising a thermally conductive shaft core material having a different composition than a portion of the shaft surrounding the thermally conductive shaft core; a rotor back assembly surrounding a portion of the shaft; and a plurality of permanent magnets radially positioned around the rotor back assembly. ### Claim 2 (depends on 1) The electric machine rotor of claim 1 further comprising a plurality of fan blades formed in an exterior surface of the rotor back assembly. ### Claim 3 (depends on 1) The electric machine rotor of claim 1 further comprising one or more ventilation channels extending through the rotor back assembly. ### Claim 4 (depends on 1) The electric machine rotor of claim 1 wherein the rotor back assembly comprises a plurality of laminations with each lamination separated from adjacent laminations with an insulating material. ### Claim 5 (depends on 1) The electric machine rotor of claim 1 wherein at least one of the plurality of permanent magnets comprises a stack of laminations, with each with each lamination comprising a rare earth magnetic material. ### Claim 6 (depends on 5) The electric machine rotor of claim 5 wherein at least one lamination is separated from another lamination by an insulating material. ### Claim 7 (depends on 1) The electric machine rotor of claim 1 further comprising: a gap between two adjacent permanent magnets; and a thermally conductive material filing the gap between the two adjacent permanent magnets, said thermally conductive material being in contact with the rotor back assembly between the two adjacent permanent magnets. ### Claim 8 (depends on 7) The electric machine rotor of claim 7 wherein the thermally conductive material comprises a polymer doped with an additive to enhance thermal conductivity. ### Claim 9 (depends on 8) The electric machine rotor of claim 8 wherein the additive comprises one or more of boron nitride, silicon carbide, silica, aluminum oxide, aluminum, copper, another metal, another metal oxide, ceramic, and graphene. ### Claim 10 (depends on 8) The electric machine rotor of claim 8 wherein the additive comprises one or more of suspended spherical particles or suspended radially oriented particles. ### Claim 11 (depends on 7) The electric machine rotor of claim 7, wherein the rotor back assembly comprises one or more slots, grooves, keyways, roughened surfaces, holes, or projections at an interface between the rotor back assembly and a surface of the thermally conductive rotor encapsulant in contact with the rotor back assembly. ### Claim 12 (depends on 7) The electric machine rotor of claim 7 further comprising a heat transfer structure in thermal communication with the thermally conductive material. ### Claim 13 (depends on 1) The electric machine rotor of claim 1 further comprising a thermally conductive band surrounding an outside face of each of the plurality of permanent magnets. ### Claim 14 (depends on 13) The electric machine rotor of claim 13 wherein the thermally conductive band comprises a plurality of steel bands. ### Claim 15 An electric machine rotor comprising: a shaft; a rotor back assembly surrounding a portion of the shaft; and a plurality of permanent magnets radially positioned around the rotor back assembly, wherein at least one of the plurality of permanent magnets comprises a stack of laminations, with each with each lamination comprising a rare earth magnetic material. ### Claim 16 (depends on 15) The electric machine rotor of claim 15 wherein at least one lamination is separated from another lamination by an insulating material. ### Claim 17 (depends on 15) The electric machine rotor of claim 15 further comprising: a gap between two adjacent permanent magnets; and a thermally conductive material filing the gap between the two adjacent permanent magnets, said thermally conductive material being in contact with the rotor back assembly between the two adjacent permanent magnets. ### Claim 18 (depends on 17) The electric machine rotor of claim 17 wherein the thermally conductive material comprises a polymer doped with an additive to enhance thermal conductivity. ### Claim 19 (depends on 18) The electric machine rotor of claim 18 wherein the additive comprises one or more of boron nitride, silicon carbide, silica, aluminum oxide, aluminum, copper, another metal, another metal oxide, ceramic, and graphene. ### Claim 20 (depends on 18) The electric machine rotor of claim 18 wherein the additive comprises one or more of suspended spherical particles or suspended radially oriented particles. ### Claim 21 (depends on 17) The electric machine rotor of claim 17, wherein the rotor back assembly comprises one or more slots, grooves, keyways, roughened surfaces, holes, or projections at an interface between the rotor back assembly and a surface of the thermally conductive rotor encapsulant in contact with the rotor back assembly. ### Claim 22 (depends on 17) The electric machine rotor of claim 17 further comprising a heat transfer structure in thermal communication with the thermally conductive material. ### Claim 23 (depends on 15) The electric machine rotor of claim 15 further comprising a thermally conductive band surrounding an outside face of each of the plurality of permanent magnets. ### Claim 24 (depends on 23) The electric machine rotor of claim 23 wherein the thermally conductive band comprises a plurality of steel bands. ### Claim 25 (depends on 15) The electric machine rotor of claim 15 further comprising a plurality of fan blades formed in an exterior surface of the rotor back assembly. ### Claim 26 (depends on 15) The electric machine rotor of claim 15 further comprising one or more ventilation channels extending through the rotor back assembly. ### Claim 27 An electric machine rotor shaft comprising: a thermally conductive shaft comprising a core material; and an outer shaft portion surrounding at least some of the thermally conductive shaft core, said outer shaft portion having a different composition than the thermally conductive shaft core.