# US 2026/0229941 A1 · Rotor for rotary electric machine, method for manufacturing rotor for rotary electric machine, rotary electric machine, and electric vehicle using rotary electric machine > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2026/0229941 A1 - Document ID: US20260229941A1 - Status: Published application - Kind: A1 - Application number: 19/151,780 - Filed: 2023-05-29 - Published: 2026-08-06 - Earliest claimed: 2023-05-29 - Assignees: Mitsubishi Electric Mobility Corporation - Applicants: Mitsubishi Electric Mobility Corporation - Inventors: Satoru SATO; Kohei YASUDA; Yoshiki KUWAHARA - Web page: https://patentgrep.com/patent/US20260229941A1 ## CPC - H02K 1/28: Means for mounting or fastening rotating magnetic parts on to, or to, the rotor structures - H02K 1/276: Magnets embedded in the magnetic core, e.g. interior permanent magnets [IPM] - H02K 1/2766: {having a flux concentration effect} - H02K 1/278: Surface mounted magnets; Inset magnets - H02K 15/03: having permanent magnets - H02K 15/035: on the rotor - H02K 15/12: Impregnating, moulding insulation, heating or drying of windings, stators, rotors or machines - Y02T 10/64: Electric machine technologies in electromobility - H02K: DYNAMO-ELECTRIC MACHINES (dynamo-electric relays H01H53/00; conversion of DC or AC input power into surge output power {H03K3/53}) - Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION ## Abstract A plurality of magnet slots are provided along the circumferential direction of a rotor core in which a plurality of electromagnetic steel plates are stacked. Permanent magnets are stored in the magnet slots, and are adhesively fixed to the inner wall surface of the magnet slots via magnet fixing resin. And work oil is present at the adhesive surface between the rotor core and the magnet fixing resin, and the work oil is present over the entire inner wall surface of the magnet slots. ## Claims ### Claim at position 1 -14. (canceled) ### Claim 15 A rotor for a rotary electric machine having a rotor core made of multiple stacked electromagnetic steel plates and a permanent magnet fixed to the rotor core via a magnet fixing resin, wherein work oil is present on the adhesive surface between the rotor core and the magnet fixing resin. ### Claim 16 (depends on 15) The rotor for the rotary electric machine according to claim 15, wherein a plurality of magnet slots are provided along the circumferential direction of the rotor core, the permanent magnets are stored in the magnet slots and adhesively fixed to the inner wall surface of the magnet slots via the magnet fixing resin, and the work oil is present on the inner wall surface. ### Claim 17 (depends on 16) The rotor for the rotary electric machine according to claim 16, wherein the magnet slot is filled with the magnet fixing resin except for the portion occupied by the permanent magnet, and the work oil is present over the entire inner wall surface. ### Claim 18 (depends on 16) The rotor for the rotary electric machine according to claim 16, wherein a flux barrier is provided in the magnet slot, and the work oil is present on an inner wall surface of the flux barrier. ### Claim 19 (depends on 15) The rotor for the rotary electric machine according to claim 15, wherein the work oil is present on an adhesive surface between the permanent magnet and the magnet fixing resin. ### Claim 20 (depends on 15) The rotor for the rotary electric machine according to claim 15, wherein the work oil is present between the laminations of the electromagnetic steel sheets that form the rotor core, and an adhesive steel sheet is used in which the laminations of the electromagnetic steel sheets are adhesively fixed each other by the magnet fixing resin. ### Claim 21 (depends on 15) The rotor for the rotary electric machine according to claim 15, wherein the work oil contains an oiliness agent component containing a polar group. ### Claim 22 (depends on 15) The rotor for the rotary electric machine according to claim 15, wherein a polar group provided in the work oil is a carboxyl group, a hydroxyl group, or an amine. ### Claim 23 (depends on 15) The rotor for the rotary electric machine according to claim 15, wherein the work oil contains an oiliness agent component in a weight percentage of 1% or more. ### Claim 24 (depends on 15) The rotor for the rotary electric machine according to claim 15, wherein the magnet fixing resin is an epoxy resin. ### Claim 25 (depends on 15) A method for manufacturing the rotor for the rotary electric machine according to claim 15, wherein a process of applying the work oil as a surface treatment to the entire surface of the rotor core is provided prior to a process of adhesively fixing the permanent magnets to the rotor core. ### Claim 26 (depends on 16) A method for manufacturing the rotor for the rotary electric machine according to claim 16, wherein a process of applying the work oil to the entire inner wall surface of the magnet slots is provided prior to a process of adhesively fixing the permanent magnet to the rotor core. ### Claim 27 (depends on 15) A method for manufacturing the rotor for the rotary electric machine according to claims 15, wherein the work oil is applied to the entire surface of the rotor core as a surface treatment prior to adhesively fixing the permanent magnets to the rotor core, and then the surface of the rotor core is cleaned under conditions in which the work oil remains on at least the adhesive surface between the rotor core and the magnet fixing resin. ### Claim 28 (depends on 20) A method for manufacturing the rotor for the rotary electric machine according to claim 20, wherein the permanent magnets are adhesively fixed to the rotor core without performing a cleaning process for removing organic matter on the surface of the rotor core after the work oil is applied as a surface treatment. ### Claim 29 (depends on 15) The rotary electric machine comprising: the rotor according to claim 15; and a stator disposed on an outer periphery of the rotor. ### Claim 30 (depends on 29) An electric vehicle using the rotary electric machine according to claim 29. ### Claim 31 (depends on 16) The rotor for the rotary electric machine according to claim 16, wherein the work oil is present on an adhesive surface between the permanent magnet and the magnet fixing resin. ### Claim 32 (depends on 17) The rotor for the rotary electric machine according to claim 17, wherein the work oil is present on an adhesive surface between the permanent magnet and the magnet fixing resin. ### Claim 33 (depends on 18) The rotor for the rotary electric machine according to claim 18, wherein the work oil is present on an adhesive surface between the permanent magnet and the magnet fixing resin. ### Claim 34 (depends on 16) The rotor for the rotary electric machine according to claim 16, wherein the work oil is present between the laminations of the electromagnetic steel sheets that form the rotor core, and an adhesive steel sheet is used in which the laminations of the electromagnetic steel sheets are adhesively fixed each other by the magnet fixing resin.