# US 10,483,817 B2 · Rotor for an electric motor including a structure for retaining rotor segments and permanent magnets on a hub thereof > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,483,817 B2 - Document ID: US10483817B2 - Status: Granted - Kind: B2 - Application number: 14/905,441 - Filed: 2014-07-15 - Published: 2016-06-09 - Granted: 2019-11-19 - Earliest claimed: 2013-07-16 - Assignees: Equipmake Ltd; AIM, Inc. - Applicants: Equipmake Ltd; aim CO., LTD. - Inventors: Yoshitoshi Sakurai; Ian Foley; Martin Ogilvie - Web page: https://patentgrep.com/patent/US10483817B2 ## CPC - H02K 1/2773: {consisting of tangentially magnetized radial magnets} - H02K 1/28: Means for mounting or fastening rotating magnetic parts on to, or to, the rotor structures - 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 suitable for use in an electric motor or generator. The rotor comprises a hub having a central axis, a plurality of rotor segments and permanent magnets, and an assembly for retaining the segments on the hub. The segments are arranged around the hub to define at least two rings, which are adjacent to each other in the axial direction with a permanent magnet disposed between each of the segments in each ring. The assembly includes a plurality of rods which extend in an axial direction to retain the rotor segments. An intermediate plate is located between each ring of segments through which the rods pass, wherein the intermediate plates and the outer circumferential surface of the hub engage with each other in such a way as to allow the intermediate plates to move axially along the hub. ## Claims ### Claim 1 A rotor for an electric motor, the rotor comprising: a hub having a central axis; a plurality of rotor segments arranged around the hub; a plurality of permanent magnets; and an assembly for retaining the segments on the hub, wherein the assembly includes a plurality of rods which extend in an axial direction so as to retain respective rotor segments, the segments are arranged around the hub to define at least two rings, which are adjacent to each other in the axial direction, the rotor includes an intermediate plate between each ring of segments, wherein the rods pass through each intermediate plate, wherein the magnets and the hub are shaped so as to engage with each other in such a way that the hub restrains the magnets in the circumferential direction, with each magnet received by and in direct engagement with a parallel-sided groove defined by an outer circumferential surface of the hub, and the intermediate plate between each ring of segments defines a series of inwardly directed projections in engagement with the grooves in the hub in such a way as to resist rotation of the intermediate plate between each ring of segments around the axis of the hub. ### Claim 2 (depends on 1) A rotor of claim 1, wherein the intermediate plate between each ring of segments and the outer circumferential surface of the hub engage with each other in such a way as to allow the intermediate plate between each ring of segments to move axially along the hub. ### Claim 3 (depends on 2) A rotor of claim 2, wherein a plurality of axially extending splines are defined by the outer circumferential surface of the hub and engage with the intermediate plate between each ring of segments. ### Claim 4 (depends on 1) A rotor of claim 1, wherein each segment defines a hole therethrough for receiving a respective rod, a radially innermost surface and a radially outermost surface, and the hole is located closer to the radially innermost surface than the radially outermost surface. ### Claim 5 (depends on 4) A rotor of claim 4, wherein the hole is located closer to a point of lowest magnetic flux change in the segment during operation of the motor than a point of highest magnetic flux change during operation of the motor. ### Claim 6 (depends on 5) A rotor of claim 5, wherein the hole is located at the point of lowest magnetic flux change in the segment during operation of the motor. ### Claim 7 (depends on 1) A rotor of claim 1, wherein the segments are arranged around the hub, with a permanent magnet disposed between each of the segments. ### Claim 8 (depends on 1) A rotor of claim 1, wherein the magnets and the segments engage with each other in such a way that the segments restrain the magnets against radially outward forces. ### Claim 9 (depends on 1) A rotor of claim 1, wherein the assembly is configured so that it does not extend radially outwardly beyond the greatest radial extent of the rotor segments. ### Claim 10 (depends on 1) A rotor of claim 1, including a pair of end plates which are coupled to respective ends of the rods. ### Claim 11 (depends on 10) A rotor of claim 10, wherein either or both of the end plates are substantially annular and extend around the hub. ### Claim 12 (depends on 10) A rotor of claim 10, wherein either or both of the end plates are fixed onto the hub. ### Claim 13 (depends on 10) A rotor of claim 10, wherein either or both of the end plates are integrally formed with the hub. ### Claim 14 (depends on 1) A rotor of claim 1, wherein a portion of at least one segment extends radially outwards beyond an adjacent magnet, and the portion extends circumferentially at least part way over the magnet to restrain the magnet against radially outward forces. ### Claim 15 (depends on 14) A rotor of claim 14, wherein a portion of each segment extends radially outwards beyond the two adjacent magnets, and the portion extends circumferentially at least part way over the two adjacent magnets to restrain them against radially outward forces. ### Claim 16 (depends on 1) An electric motor including a rotor of claim 1.