# US 2013/0154436 A1 · Permanent magnet type rotary electric machine and electric power steering apparatus using the same > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2013/0154436 A1 - Document ID: US20130154436A1 - Status: Published application - Kind: A1 - Application number: 13/697,064 - Filed: 2010-09-06 - Published: 2013-06-20 - Earliest claimed: 2010-09-06 - Assignees: Mitsubishi Electric Corporation - Inventors: Masatsugu Nakano; Toshihiro Matsunaga; Yusuke Morita; Misa Nakayama; Kazuhisa Takashima; Satoru Akutsu - Web page: https://patentgrep.com/patent/US20130154436A1 ## CPC - H02K 1/16: Stator cores with slots for windings - B62D 5/046: {Controlling the motor} - H02K 1/146: {consisting of a generally annular yoke with salient poles} - H02K 1/148: {Sectional cores (H02K1/141 takes precedence)} - H02K 1/276: Magnets embedded in the magnetic core, e.g. interior permanent magnets [IPM] - H02K 1/278: Surface mounted magnets; Inset magnets - H02K 21/16: having annular armature cores with salient poles (with homopolar co-operation H02K21/20) - H02K 29/03: with a magnetic circuit specially adapted for avoiding torque ripples or self-starting problems - 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}) - B62D: MOTOR VEHICLES; TRAILERS (steering, or guiding on a desired track, of agricultural machines or implements A01B69/00; wheels, castors, axles, increasing wheel adhesion B60B; vehicle tyres, tyre inflation or tyre changing B60C; connections between vehicles of a train or the like B60D; vehicles for use on rail and road, amphibious or convertible vehicles B60F; suspension arrangements B60G; heating, cooling, ventilating or other air treating devices B60H; windows, windscreens, non-fixed roofs, doors or similar devices, protective coverings for vehicles not in use B60J; propulsion plant arrangements, auxiliary drives, transmissions, controls, instrumentation or dashboards B60K; electric equipment or propulsion of electrically-propelled vehicles B60L; power supply for electrically-propelled vehicles B60M; passenger accommodation not otherwise provided for B60N; adaptations for load transportation or to carry special loads or objects B60P; arrangement of signalling or lighting devices, the mounting or supporting thereof or circuits therefor, for vehicles in general B60Q; vehicles, vehicle fittings or vehicle parts not otherwise provided for B60R; servicing, cleaning, repairing, supporting, lifting, or manoeuvring, not otherwise provided for, B60S; brake arrangements, brake control systems or parts thereof B60T; air-cushion vehicles B60V; motor-cycles, accessories therefor B62J, B62K; testing of vehicles G01M) ## Abstract Not less than two regions different in magnetic circuit design are provided in a rotational axis direction of the rotor (30), the regions being different by changing a cross-sectional shape in the rotational axis direction in a cross-section perpendicular to a rotational shaft (10) of the rotor (30) having the permanent magnets (1) and the rotor core (2); the supplemental grooves (5) are provided in axial partial regions of each of the teeth (7) of the stator core (3); and the region in which the supplemental groove (5) is provided is each partial region for each region facing a region same in magnetic circuit design of the rotor (30). This enables to reduce cogging torque generated by variations on the rotor side. ## Claims ### Claim at position 1 1-15. (canceled) ### Claim 16 A permanent magnet type rotary electric machine comprising: a rotor having a plurality of magnetic poles composed of permanent magnets and a rotor core; and a stator including armature windings and a stator core which is provided with slots for incorporating said armature windings and has a plurality of teeth facing said rotor, each of said teeth of said stator core being provided with supplemental grooves at portions facing said rotor, wherein not less than two regions different in magnetic circuit design are provided in a rotational axis direction of said rotor, the regions being different by changing a cross-sectional shape in the rotational axis direction in a cross-section perpendicular to a rotational shaft of said rotor having said permanent magnets and said rotor core; the supplemental grooves are provided in axial partial regions of said tooth of said stator core; and the region in which the supplemental groove is provided is each partial region for each region facing a region same in magnetic circuit design of the rotor. ### Claim 17 (depends on 16) The permanent magnet type rotary electric machine according to claim 16, wherein the region in which the supplemental groove is provided is a region half of each axial length for each region facing a region same in magnetic circuit design of the rotor. ### Claim 18 (depends on 16) The permanent magnet type rotary electric machine according to claim 16, wherein said rotor core is provided with protrusion portions, which retain said permanent magnets, at portions in the rotational axis direction; the supplemental grooves are provided in axial partial regions of said tooth of said stator core; and the region in which the supplemental groove is provided is each partial region for each region facing a region in which the protrusion portion is provided and a region in which the protrusion portion is not provided. ### Claim 19 (depends on 17) The permanent magnet type rotary electric machine according to claim 17, wherein said rotor core is provided with protrusion portions, which retain said permanent magnets, at portions in the rotational axis direction; the supplemental grooves are provided in axial partial regions of said tooth of said stator core; and the region in which the supplemental groove is provided is a region half of each axial length for each region facing a region in which the protrusion portion is provided and a region in which the protrusion portion is not provided. ### Claim 20 (depends on 16) The permanent magnet type rotary electric machine according to claim 16, wherein the width Wd of the supplemental groove is larger than the opening width Ws of the slot. ### Claim 21 (depends on 16) The permanent magnet type rotary electric machine according to claim 16, wherein the depth Hd of the supplemental groove is larger than the thickness Hs of an end portion of said tooth. ### Claim 22 (depends on 16) The permanent magnet type rotary electric machine according to claim 16, wherein the supplemental groove is not provided in an axial end portion of said stator core. ### Claim 23 (depends on 16) The permanent magnet type rotary electric machine according to claim 16, wherein the supplemental groove is provided at one place in a circumferential center portion of said stator core at a portion in which the tooth faces said rotor. ### Claim 24 (depends on 17) The permanent magnet type rotary electric machine according to claim 17, wherein the supplemental groove is provided at one place in a circumferential center portion of said stator core at a portion in which the tooth faces said rotor. ### Claim 25 (depends on 18) The permanent magnet type rotary electric machine according to claim 18, wherein the supplemental groove is provided at one place in a circumferential center portion of said stator core at a portion in which the tooth faces said rotor. ### Claim 26 (depends on 19) The permanent magnet type rotary electric machine according to claim 19, wherein the supplemental groove is provided at one place in a circumferential center portion of said stator core at a portion in which the tooth faces said rotor. ### Claim 27 (depends on 16) The permanent magnet type rotary electric machine according to claim 16, wherein when the number of poles of said magnetic poles of said rotor is P and the number of the slots of said stator is S, the following relationship is established: 0.75