# US 2017/0288484 A1 · Spoked rotor with inner structural bridges providing low flux leakage > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2017/0288484 A1 - Document ID: US20170288484A1 - Status: Published application - Kind: A1 - Application number: 15/474,913 - Filed: 2017-03-30 - Published: 2017-10-05 - Earliest claimed: 2016-03-31 - Assignees: Nidec Motor Corporation - Applicants: Nidec Motor Corporation - Inventors: Ryan M. Bastien - Web page: https://patentgrep.com/patent/US20170288484A1 ## CPC - H02K 1/2773: {consisting of tangentially magnetized radial magnets} - H02K 1/2706: Inner rotors - H02K 2213/03: Machines characterised by numerical values, ranges, mathematical expressions or similar information - H02K: DYNAMO-ELECTRIC MACHINES (dynamo-electric relays H01H53/00; conversion of DC or AC input power into surge output power {H03K3/53}) ## Abstract A rotor is provided for use in an electric motor. The rotor is rotatable about an axis. The rotor includes a core including a plurality of arcuately arranged pole segments arranged arcuately the axis. The rotor further includes a plurality of arcuately arranged magnets alternating with the pole segments, such that each of the magnets is at least in part interposed between a pair of adjacent pole segments. Still further, the rotor includes a support structure at least in part supporting the pole segments. The core further includes a plurality of bridges. Each of the bridges extends between and interconnects a corresponding one of the pole segments to the support structure. Each of the bridges includes a plurality of axially spaced apart bridge segments. ## Claims ### Claim 1 A rotor for use in an electric motor and rotatable about an axis, said rotor comprising: a core including a plurality of pole segments arranged arcuately about the axis; a plurality of arcuately arranged magnets alternating with the pole segments, such that each of the magnets is at least in part interposed between a pair of adjacent pole segments; and a support structure at least in part supporting the pole segments, said core further including a plurality of bridges, each of said bridges extending between and interconnecting a corresponding one of said pole segments to said support structure, each of said bridges comprising a plurality of axially spaced apart bridge segments. ### Claim 2 (depends on 1) The rotor of claim 1, said core comprising a plurality of stacked laminations, said laminations cooperatively defining the pole segments and the bridges. ### Claim 3 (depends on 2) The rotor of claim 2, said laminations being at least substantially identical to one another. ### Claim 4 (depends on 3) The rotor of claim 3, axially adjacent ones of said laminations being arcuately offset from one another about the axis by a rotation angle. ### Claim 5 (depends on 4) The rotor of claim 4, said rotation angle being such that axially alternating ones of said laminations cooperatively define each of said bridges. ### Claim 6 (depends on 5) The rotor of claim 5, each of said pole segments presenting a geometric centerline, said geometric centerlines being arcuately offset from one another about the axis by a pole segment spacing angle, said rotation angle and said spacing angle being at least substantially equal. ### Claim 7 (depends on 6) The rotor of claim 6, said core including ten of said pole segments, said rotation angle and said spacing angle each being about 36°. ### Claim 8 (depends on 2) The rotor of claim 2, each of said laminations comprising a plurality of arcuately arranged pole segment portions and a plurality of said bridge segments, each of said bridge segments portions extending from a corresponding one of said pole segment portions. ### Claim 9 (depends on 8) The rotor of claim 8, each of said laminations comprising fewer of said bridge segments than said pole segment portions. ### Claim 10 (depends on 9) The rotor of claim 9, said bridge segments extending from arcuately alternating ones of said pole segment portions. ### Claim 11 (depends on 10) The rotor of claim 10, each of said bridges comprising an at least substantially aligned set of said bridge segments. ### Claim 12 (depends on 11) The rotor of claim 11, each of said sets comprising bridge segments of axially alternating ones of the laminations. ### Claim 13 (depends on 2) The rotor of claim 2, said laminations cooperatively defining said support structure. ### Claim 14 (depends on 1) The rotor of claim 1, said rotor further comprising a shaft rotatable about the axis, said support structure being fixed to said shaft to rotate therewith. ### Claim 15 (depends on 1) The rotor of claim 1, said support structure being disposed radially inside said pole segments. ### Claim 16 (depends on 1) The rotor of claim 1, said core including said support structure. ### Claim 17 (depends on 1) The rotor of claim 1, each of said pole segments presenting a minimum generally arcuate pole segment width, each of said bridges presenting a minimum generally arcuate bridge width, said bridge width being between about 25% percent and about 75% said pole segment width. ### Claim 18 (depends on 17) The rotor of claim 17, said bridge width being about half of said pole segment width. ### Claim 19 (depends on 1) The rotor of claim 1, said core further including a plurality of outer bridges extending between and connecting adjacent ones of the pole segments. ### Claim 20 (depends on 19) The rotor of claim 19, said pole segments at least in part cooperatively presenting an annular core face, said core face at least in part defining a core envelope, said core envelope defining a core radius, each of said pole segments including— a main body presenting a body face extending concentrically with the axis and disposed along the envelope, said body face presenting a pair of arcuately spaced apart body edges, and a pair of ears each extending generally arcuately outwardly from a corresponding one of the body edges, each of said ears presenting a substantially flat ear face extending directly from the corresponding one of the body edges, each of said ear faces defining a taper angle relative to a tangent plane defined at the corresponding one of the body edges, each of said ear faces being disposed radially inside the envelope and presenting a radially innermost ear edge disposed radially inwardly of said envelope by an ear recess distance, said taper angle being between about 4 degrees and about 8 degrees, said ear recess distance being between about 0.2% and 0.5% of said core radius.