An embodiment comprises: a housing; a bobbin disposed in the housing; a coil disposed on the bobbin; a magnet disposed in a side portion of the housing, and including a first side surface facing the coil and a second side surface opposite to the first side surface; and a yoke disposed in the upper portion of the housing and overlapping the magnet in the optical axis direction, wherein: the centerline of the magnet is located on one side with reference to a reference line; a first groove adjoining one end of the first side surface of the magnet is disposed at a first end of the magnet; a second groove adjoining the other end of the first side surface of the magnet is disposed at a second end of the magnet; the reference line passes through the center of the housing and is perpendicular to the outer surface of the side portion of the housing where the magnet is disposed; and the centerline of the magnet is a straight line passing through the center between the first end and the second end of the magnet and perpendicular to the first side surface of the magnet.

A device has a housing and rotors rotatably coupled to the housing. Each rotor has a magnet on at least one side of the rotor. Printed circuit board (PCB) stators are located axially between the rotors and coupled to the housing. The PCB stators have layers, and each layer has coils. The number of rotors disks is equal to the number of stators plus one. The stators are interleaved with the rotors. A shaft is coupled to the rotors and the housing. The shaft has a hollow section coupled to a source of a liquid coolant through a rotary connector and to radial channels in the shaft that dispense a liquid coolant between the rotors and PCB stators. The shaft has flanges with different diameters configured to receive the rotors disks with respective matching bore diameters. In addition, the housing has a sump to collect the liquid coolant.

An axial flux motor includes a housing; a drive shaft disposed within the housing; at least one rotor; and at least one stator. The at least one rotor includes a diametrically-magnetized single pole pair magnetic ring having a rotor aperture defined through the center of the magnetic ring, where the drive shaft extends through the rotor aperture and where the at least one rotor is fixed to the drive shaft. The at least one stator includes a number of conductive windings and a stator aperture, where the drive shaft extends through the stator aperture and where the drive shaft is rotatable within the aperture. The at least one stator is configured to generate an axial magnetic field that causes the at least one rotor to rotate, thereby rotating the drive shaft.

An axial flux generator comprising: two magnetic annuli; a coil annulus; the magnetic annuli and coil annulus having a common axis; the two magnetic annuli defining a plurality of magnetic fields around the common axis extending across a gap between the two magnetic annuli and the coil annulus having a sequence of coils around the common axis in the gap such that the lines of magnetic flux from the magnetic fields cut the turns of the coils and this induces electric current in the coils as the magnetic annuli are caused to rotate relative to the coil annulus; wherein each coil has a shape in a plane perpendicular to the common axis where a first position and a second position on the shape are at a radial distance from the common axis that is greater than the radial distance from the common axis of a radially innermost position of the shape by an amount that is at least 60% of the difference in radial distance from the common axis between the radially innermost position and a radially outermost position of the shape and the first position and second position are on opposite sides of the shape at a radial location where the shape has a maximum dimension in a direction perpendicular to the radial direction, and a portion of the shape that is radially outward from the first and second positions is within an area bounded by an inner line and an outer line between the first and second positions, the inner line and the outer line both being radially outward from the first and second positions and having a radius that is 0.625 times the maximum dimension of the shape in the direction perpendicular to the radial direction, and the outer line being longer than the inner line.

An axial flux generator comprising: two magnetic annuli; a coil annulus; the magnetic annuli and coil annulus having a common axis; the two magnetic annuli defining a plurality of magnetic fields around the common axis extending across a gap between the two magnetic annuli and the coil annulus having a sequence of coils around the common axis in the gap such that the lines of magnetic flux from the magnetic fields cut the turns of the coils and this induces electric current in the coils as the magnetic annuli are caused to rotate relative to the coil annulus; wherein each coil has a shape in a plane perpendicular to the common axis where a first position and a second position on the shape are at a radial distance from the common axis that is greater than the radial distance from the common axis of a radially innermost position of the shape by an amount that is at least 60% of the difference in radial distance from the common axis between the radially innermost position and a radially outermost position of the shape and the first position and second position are on opposite sides of the shape at a radial location where the shape has a maximum dimension in a direction perpendicular to the radial direction, and a portion of the shape that is radially outward from the first and second positions is within an area bounded by an inner line and an outer line between the first and second positions, the inner line and the outer line both being radially outward from the first and second positions and having a radius that is 0.625 times the maximum dimension of the shape in the direction perpendicular to the radial direction, and the outer line being longer than the inner line.

A micro fan is provided. The micro fan includes a rotor and a stator. The stator includes a plurality of axial induced coil units and a circuit board. The axial induced coil units are respectively preformed as a plurality of stator magnetic pole units, and are coupled to the circuit board. At least one of the coil units includes a coil and insulation material. The insulation material is block-shaped and covers at least a portion of the coil, and the central axis of the coil is parallel to the shaft of the rotor.

A micro fan is provided. The micro fan includes a rotor and a stator. The stator includes a plurality of axial induced coil units and a circuit board. The axial induced coil units are respectively preformed as a plurality of stator magnetic pole units, and are coupled to the circuit board. At least one of the coil units includes a coil and insulation material. The insulation material is block-shaped and covers at least a portion of the coil, and the central axis of the coil is parallel to the shaft of the rotor.

An electromagnetic coil where a conductive member is wound so as to surround an air core region includes an effective coil portion, a first coil end portion, and a second coil end portion. The effective coil portion is formed of a coil-use conductive wire formed by bundling a plurality of conductive base members, the first coil end portion is formed of a first end member that is made of a solid conductive material, and the second coil end portion is formed of a second end member made of a solid conductive material. In the air core region of “one magnetic material” to which an electric current of a first phase is supplied, the effective coil portion of “the other electromagnetic coil” to which an electric current of a second phase is supplied is fitted.

An electromagnetic coil where a conductive member is wound so as to surround an air core region includes an effective coil portion, a first coil end portion, and a second coil end portion. The effective coil portion is formed of a coil-use conductive wire formed by bundling a plurality of conductive base members, the first coil end portion is formed of a first end member that is made of a solid conductive material, and the second coil end portion is formed of a second end member made of a solid conductive material. In the air core region of “one magnetic material” to which an electric current of a first phase is supplied, the effective coil portion of “the other electromagnetic coil” to which an electric current of a second phase is supplied is fitted.

A stator for interacting with magnets carried by a rotor of an electric machine, the stator comprising: an active region arranged to be aligned with the magnets carried by the rotor; a first inactive region and a second inactive region, wherein the first and second inactive regions are separated by the active region; and a slotless phase winding comprising a plurality of conductive elements, wherein each conductive element comprises a conductor provided in an insulating housing, and wherein the slotless phase winding is arranged in a serpentine structure comprising: a first active segment in which the conductive elements extend across the active region from the first inactive region to the second inactive region; a second active segment in which the conductive elements extend across the active region from the second inactive region to the first inactive region; and an inactive segment coupling the first active segment to the second active segment, wherein the inactive segment comprises a turn provided in the second inactive region, and wherein at least one of the conductive elements is twisted in the second inactive region.