Abstract: The present disclosure provides a brushless permanent magnet machine which includes an essentially circular shaped rotor, and a pair of magnets arranged in the rotor. The magnets are each U-shaped and have a thickness direction extending along a contour of the corresponding magnet between the opposite poles of the corresponding magnet, respectively. The magnets are each composed of a non-rare earth material having a lower coercivity than a rare earth material. A direction of magnetization of each of the pair of magnets is parallel to the thickness direction of the corresponding magnet. The present disclosure also provides a method of manufacturing such a brushless permanent magnet machine.

Abstract: The present disclosure provides a brushless permanent magnet machine which includes an essentially circular shaped rotor, and a pair of magnets arranged in the rotor. The magnets are each U-shaped and have a thickness direction extending along a contour of the corresponding magnet between the opposite poles of the corresponding magnet, respectively. The magnets are each composed of a non-rare earth material having a lower coercivity than a rare earth material. A direction of magnetization of each of the pair of magnets is parallel to the thickness direction of the corresponding magnet. The present disclosure also provides a method of manufacturing such a brushless permanent magnet machine.

Abstract: A rotor includes a cylindrical rotor core having an outer circumferential surface and a plurality of magnet insertion holes formed in the rotor core and arranged circumferentially at a preset angular interval about the rotational axis of the rotor core. Each hole extends in a direction parallel to the rotational axis and has a cross section of a generally elongated slit. The elongated slit is curved concave relative to the circumferential surface and has a radially inward side, a radially outward side, and two ends that are respectively spaced apart from the circumferential surface by two bridges, wherein each bridge has thinner and thicker portions that are respectively positioned near the radially inward and outward sides. One or more permanent magnets are inserted in each hole and arranged to transfer centrifugal forces acting on the magnets during operation to portions of the bridges.

Abstract: A rotor includes a cylindrical rotor core having an outer circumferential surface and a plurality of magnet insertion holes formed in the rotor core and arranged circumferentially at a preset angular interval about the rotational axis of the rotor core. Each hole extends in a direction parallel to the rotational axis and has a cross section of a generally elongated slit. The elongated slit is curved concave relative to the circumferential surface and has a radially inward side, a radially outward side, and two ends that are respectively spaced apart from the circumferential surface by two bridges, wherein each bridge has thinner and thicker portions that are respectively positioned near the radially inward and outward sides. One or more permanent magnets are inserted in each hole and arranged to transfer centrifugal forces acting on the magnets during operation to portions of the bridges.

Abstract: A brushless permanent magnet electric motor or generator having a hollow rotor, is provided with apertures in ends of the rotor. The apertures allow air to flow through the center of the hollow rotor and remove heat from the rotor. Vanes or blades can be fixed to the shaft within the rotor or fixed to ends of the rotor to force air through an interior of the hollow rotor. Ends of the rotor can be shaped to form fan blades that draw air through the interior of the rotor. Air flowing through the rotor can be recirculated by flowing back through passageways formed between the stator and the motor/generator casing, through passages through the stator, and/or back through an air gap between the stator and the rotor.