A dual-rotor machine comprising a dual rotor support structure rotatably connected to a frame. A stationary stator is disposed between the rotors and is fixed to the frame. An inner rotor and outer rotor, each comprising a permanent magnet Halbach array, are coaxially disposed with the stator and are rotable about the stator. In this configuration, the inner rotor channels its magnetic flux to its outside, while the outer rotor channels its magnetic flux to its inside. The magnetic flux density at the stator for the dual-rotor machine can be as high as 2 Tesla or higher for high-grade neodymium-iron-boron permanent magnet material, and the stored magnetic energy for conversion to mechanical or electrical energy available to the stator may be at least 0.5 KJ/m. The rotor Halbach arrays may comprise monolithic permanent magnets with continuously variable magnetic field direction.

A dual-rotor machine comprising a dual rotor support structure rotatably connected to a frame. A stationary stator is disposed between the rotors and is fixed to the frame. An inner rotor and outer rotor, each comprising a permanent magnet Halbach array, are coaxially disposed with the stator and are rotable about the stator. In this configuration, the inner rotor channels its magnetic flux to its outside, while the outer rotor channels its magnetic flux to its inside. The magnetic flux density at the stator for the dual-rotor machine can be as high as 2 Tesla or higher for high-grade neodymium-iron-boron permanent magnet material, and the stored magnetic energy for conversion to mechanical or electrical energy available to the stator may be at least 0.5 KJ/m. The rotor Halbach arrays may comprise monolithic permanent magnets with continuously variable magnetic field direction.

A high-efficiency, high specific power electric motor/generator provides a set of permanent magnets retained at their axial ends by a wedge interface minimizing structure between the magnets and electrical coils to maximize magnetic coupling and torque production.

A high-efficiency, high specific power electric motor/generator provides a set of permanent magnets retained at their axial ends by a wedge interface minimizing structure between the magnets and electrical coils to maximize magnetic coupling and torque production.

A power tool includes a motor, a power supply device, and an output portion. The motor is used for providing power for the power tool. The motor includes a stator and a rotor rotating relative to the stator. The rotor includes a rotor core and magnetic steels disposed on the rotor core. The power supply device is electrically connected to at least the motor. The output portion is driven by the motor. The rotor core includes limiting portions arranged at intervals around an axis L, and the limiting portions are used for fixing the magnetic steels. The preceding technical solutions are adopted, which is conducive to reducing the mass of the motor, thereby reducing the loss of the motor and improving the efficiency of the motor.

In-wheel electric machines (e.g., electric motors, electric generators, etc.) for electric vehicles are disclosed. An example in-wheel electric machine includes a stator and a rotor. The stator includes a ferromagnetic core, a plurality of teeth circumferentially arranged about the ferromagnetic core, and a plurality of edgewise coils coupled to the plurality of teeth. Respective ones of the plurality of teeth extend in a radially outward direction from the ferromagnetic core and are spaced apart from one another by respective ones of a plurality of slots. Respective ones of the plurality of edgewise coils are radially loaded onto the respective ones of the plurality of teeth. The rotor is located externally relative to the stator and is configured to rotate relative to the stator. The rotor includes a plurality of permanent magnets arranged in a Halbach array.

In-wheel electric machines (e.g., electric motors, electric generators, etc.) for electric vehicles are disclosed. An example in-wheel electric machine includes a stator and a rotor. The stator includes a ferromagnetic core, a plurality of teeth circumferentially arranged about the ferromagnetic core, and a plurality of edgewise coils coupled to the plurality of teeth. Respective ones of the plurality of teeth extend in a radially outward direction from the ferromagnetic core and are spaced apart from one another by respective ones of a plurality of slots. Respective ones of the plurality of edgewise coils are radially loaded onto the respective ones of the plurality of teeth. The rotor is located externally relative to the stator and is configured to rotate relative to the stator. The rotor includes a plurality of permanent magnets arranged in a Halbach array.