Electric motor

• US 20050140235A1
• Filed: 12/03/2004
• Published: 06/30/2005
• Est. Priority Date: 12/26/2003
• Status: Active Grant

• Current Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Original Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Inventors: Hirose, Yoshihisa, Yamagishi, Yoshihiko
• Granted Patent: US 7,122,930 B2
• Time in Patent Office: Days
• US Class Current: 310/156.530
• CPC Class Codes: B60L 1/003 to auxiliary motors, e.g. for pumps, compressors
• CPC Class Codes: B60L 2200/40 Working vehicles
• CPC Class Codes: B60L 2240/36 Temperature of vehicle components or parts
• CPC Class Codes: B60L 3/0061 relating to electrical machines
• CPC Class Codes: B60L 50/16 with provision for separate direct mechanical propulsion
• CPC Class Codes: B60L 50/62 charged by low-power generators primarily intended to support the batteries, e.g. range extenders
• CPC Class Codes: H02K 1/276 Magnets embedded in the magnetic core, e.g. interior permanent magnets [IPM]
• CPC Class Codes: H02K 1/32 with channels or ducts for flow of cooling medium
• CPC Class Codes: Y02T 10/62 Hybrid vehicles
• CPC Class Codes: Y02T 10/64 Electric machine technologies in electromobility
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/7072 Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors

Abstract

An electric motor including a stator with a plurality of coils wound around a ring-shaped iron core, and a rotor rotatably disposed inside the stator is provided. The rotor includes a rotor shaft and a yoke. The yoke is provided near its periphery with a plurality of plate-like permanent magnets arranged at equal pitches. Heat generated from the rotor is released through a plurality of air holes formed in the yoke between the rotor shaft and the permanent magnets.

Claims

1. An electric motor comprising:

a stator with a plurality of coils wound around a ring-shaped iron core; and

a rotor rotatably disposed inside the stator;

the rotor comprising;

a rotor shaft;

a yoke integrally mounted on the rotor shaft;

a plurality of magnet holes formed at equal pitches near a periphery of the yoke; and

a plurality of plate-like permanent magnets disposed in the magnet holes, respectively;

wherein the yoke has a plurality of air holes, provided between the rotor shaft and the permanent magnets, for accelerating heat release of the rotor.

2. An electric motor as set forth in claim 1, wherein with a center of the rotor shaft as C, one of the permanent magnets as M1, a point of intersection of a perpendicular line drawn from the center C to the permanent magnet M1 and the periphery of the yoke as P1, a permanent magnet adjacent to the permanent magnet M1 as M2, a point of intersection of a perpendicular line drawn from the center C to the permanent magnet M2 and the periphery of the yoke as P2, and a point of intersection where a radial line passing through the center C and a midpoint between the adjacent permanent magnets M1, M2 intersects with the periphery of the yoke as Q, when a circle of a radius r passing through the intersection point P1 and/or the intersection point P2 is drawn around the intersection point Q, the air holes are formed outside of the circle.