A brushless direct-current (BLDC) motor is provided. The motor includes a stator including a stator core, stator teeth, and windings; a rotor shaft disposed within the stator and extending along a longitudinal axis; and a rotor. The rotor includes a rotor core including an inner body mounted on the rotor shaft and radial projections projecting outwardly from the inner body, a permanent magnet mounted on an outer end of the radial projections, and a mold structure formed in contact with the radial projections and configured to secure the permanent magnet to the rotor core.

A brushless direct-current (BLDC) motor is provided. The motor includes a stator including a stator core, stator teeth, and windings; a rotor shaft disposed within the stator and extending along a longitudinal axis; and a rotor. The rotor includes a rotor core including an inner body mounted on the rotor shaft and radial projections projecting outwardly from the inner body, a permanent magnet mounted on an outer end of the radial projections, and a mold structure formed in contact with the radial projections and configured to secure the permanent magnet to the rotor core.

A brushless direct-current (BLDC) motor is provided. The motor includes a stator including a stator core, stator teeth, and windings; a rotor shaft disposed within the stator and extending along a longitudinal axis; and a rotor. The rotor includes a rotor core having a cylindrical body, a permanent magnet ring mounted on an outer surface of the cylindrical body with no intermediate adhesive therebetween, and metal sleeve securely fitted outside the permanent magnet ring. The metal sleeve includes a flange extending radially inwardly that covers an axial end of the permanent magnet ring and is bonded to the rotor core to secure the permanent magnet ring to the rotor core.

A brushless direct-current (BLDC) motor is provided. The motor includes a stator including a stator core, stator teeth, and windings; a rotor shaft disposed within the stator and extending along a longitudinal axis; and a rotor. The rotor includes a rotor core having a cylindrical body, a permanent magnet ring mounted on an outer surface of the cylindrical body with no intermediate adhesive therebetween, and metal sleeve securely fitted outside the permanent magnet ring. The metal sleeve includes a flange extending radially inwardly that covers an axial end of the permanent magnet ring and is bonded to the rotor core to secure the permanent magnet ring to the rotor core.

One variation of a system for an electric motor includes a rotor including magnetic elements within a body. The system also includes a stator including coil assemblies arranged about the rotor. Each coil assembly includes an outer hook element and an inner hook element. The outer hook element extends across a first axial face and an outer radial surface of the rotor. The inner hook element: extends across a second axial face of the rotor; extends partially across the inner radial surface of the rotor; and is coupled to the outer hook element to define a throat configured to locate the rotor within the coil assembly. The system includes a shaft coupled to the inner radial surface of the rotor. Furthermore, the system includes a controller configured to drive current through the coil assemblies to generate a toroidal magnetic field configured to couple the magnetic elements to rotate the rotor.

One variation of a system for an electric motor includes a rotor including magnetic elements within a body. The system also includes a stator including coil assemblies arranged about the rotor. Each coil assembly includes an outer hook element and an inner hook element. The outer hook element extends across a first axial face and an outer radial surface of the rotor. The inner hook element: extends across a second axial face of the rotor; extends partially across the inner radial surface of the rotor; and is coupled to the outer hook element to define a throat configured to locate the rotor within the coil assembly. The system includes a shaft coupled to the inner radial surface of the rotor. Furthermore, the system includes a controller configured to drive current through the coil assemblies to generate a toroidal magnetic field configured to couple the magnetic elements to rotate the rotor.

The present disclosure provides a molding method, a manufacturing method and a molding device for a radially anisotropic multipolar solid magnet, a micro-motor rotor using this magnet, and a component for a motor. A mold core is removed from a mold, and oriented poles, the number of which is the same as that of poles of a radially anisotropic multipolar solid cylindrical magnet, are arranged outside the mold. The sum L of widths or arc lengths of top ends of all the oriented poles is greater than or equal to 0.9πD, where D is the outer diameter of a mold sleeve. The magnet production method breaks through the dimensional restriction to the manufacturing of radially anisotropic multipolar magnets in the prior art, and can produce radially anisotropic multipolar magnets having an inner diameter or diameter less than 3 mm or even less for high-precision micro-motors.

The present disclosure provides a molding method, a manufacturing method and a molding device for a radially anisotropic multipolar solid magnet, a micro-motor rotor using this magnet, and a component for a motor. A mold core is removed from a mold, and oriented poles, the number of which is the same as that of poles of a radially anisotropic multipolar solid cylindrical magnet, are arranged outside the mold. The sum L of widths or arc lengths of top ends of all the oriented poles is greater than or equal to 0.9πD, where D is the outer diameter of a mold sleeve. The magnet production method breaks through the dimensional restriction to the manufacturing of radially anisotropic multipolar magnets in the prior art, and can produce radially anisotropic multipolar magnets having an inner diameter or diameter less than 3 mm or even less for high-precision micro-motors.

A rotor for a permanent magnet motor, including a rotor body having a cylindrical surface having a circumference. A plurality of magnets are disposed on the cylindrical surface at spaced intervals at the circumference, each of the magnets having a base disposed on the cylindrical surface and a top oriented radially away from the base, a sloping front side and a sloping rear side defining with the base and top an isosceles trapezoid shape in a cross sectional plane normal to an axis of rotation of the rotor, the isosceles trapezoid shape being broader at the base. A plurality of magnet retainers, each magnet retainer disposed between a neighboring pair of the plurality of magnets, include angled faces that engage respective front and rear sides of adjacent pairs of the plurality of magnets.

A rotor for a permanent magnet motor, including a rotor body having a cylindrical surface having a circumference. A plurality of magnets are disposed on the cylindrical surface at spaced intervals at the circumference, each of the magnets having a base disposed on the cylindrical surface and a top oriented radially away from the base, a sloping front side and a sloping rear side defining with the base and top an isosceles trapezoid shape in a cross sectional plane normal to an axis of rotation of the rotor, the isosceles trapezoid shape being broader at the base. A plurality of magnet retainers, each magnet retainer disposed between a neighboring pair of the plurality of magnets, include angled faces that engage respective front and rear sides of adjacent pairs of the plurality of magnets.