When a laminated core is formed in an annular shape, a radially inner part of a contact surface formed by a projecting end of a first core piece and a recessed end of another first core piece that are adjacent in a circumferential direction, and a radially inner part of a contact surface formed by a projecting end of a second core piece and a recessed end of another second core piece that are adjacent in the circumferential direction, are positioned in a plane including a center axis of the annular laminated core.

A manufacturing method of a motor core includes laminating in an axial direction steel plates extending in a radial direction with respect to a central axis, each of the laminate steel plates including a base portion on a radially outer side of the central axis, annular portions separately disposed on a radially outer side of the base portion with penetrating portions therebetween, and connecting portions at predetermined intervals in a circumferential direction to extend in the radial direction and connect the base portion and the annular portions, the annular portions including coupling portions adjacent to both circumferential sides of the connecting portions, and cutting at least one of the two coupling portions adjacent to one connecting portion in the circumferential direction from an outer side to an inner side of the laminate steel plates in the radial direction with respect to the laminate steel plates that are laminated.

A stator includes a yoke extending to surround an axis, and having an outer circumference and an inner circumference. The yoke has a crimping portion projecting from the outer circumference, and a split surface provided at a position different from a position of the crimping portion. The yoke has a magnetic path which is provided between the outer circumference and the inner circumference and through which magnetic flux flows. When L1 represents the width of the magnetic path, and L2 represents the width of the yoke including the crimping portion, L1<L2<2.6×L1 is satisfied.

A rotor of an electric motor may include a basic shaft, a plurality of plate stacks, at least one balancing element structured and arranged to offset imbalances, and a drive element. The at least one balancing element and the drive element may be integrally provided as a one-piece, monolithic component.

A rotor core has steel laminations stacked in the axial direction, and a permanent magnet is embedded in the rotor core. A stator core has steel laminations stacked in the axial direction, and a coil is wound on the stator core. The stator core has a slot for housing the coil. The stator core has a first core portion at an end portion in the axial direction and a second core portion at a center portion in the axial direction. An area of the slot is larger in the first core portion than in the second core portion. A sheet thickness T0 and a lamination gap L0 of the steel laminations of the rotor core and a sheet thickness T1 and a lamination gap L1 of the steel laminations of the first core portion of the stator core satisfy at least one of 0.05 mm≤T0−T1≤0.15 mm and L0<L1.

An electric motor includes: a stator including a first stator core, a second stator core, and a slot in which a stator winding is disposed, and a rotor including a first rotor core facing a first stator core in a radial direction and a second stator core facing the second stator core in the radial direction. The first stator core and the second stator core are laminated in an axial direction. The stator includes a depression formed in a position facing the slot and not touching the stator winding. A volume of the first rotor core is smaller than a volume of the second rotor core.

A permanent magnet electric machine (PM machine) for a vehicle or other system includes a rotor assembly, fixed permanent magnets, a stator, an actuator, and one or more repositionable/moveable flux-shunting elements. The flux-shunting element is repositioned to control flux at specific operating points of the PM machine. The rotor assembly has a rotor coaxially surrounding and coupled to a rotor shaft. The permanent magnets are mounted to or in the rotor, and the moveable flux-shunting element is positioned between the rotor shaft and a respective one of the permanent magnets. Inboard and outboard ends of each respective permanent magnet may be oriented toward the rotor shaft and stator, respectively. The actuator selectively positions the moveable flux-shunting element at one or more operating points of the PM machine to vary reluctance in a magnetic circuit formed by the stator and rotor assembly.

A method for manufacturing a laminated body includes: laminating an electromagnetic steel plate to form the laminated body; performing an annealing process on the laminated body; acquiring a before-annealing lamination thickness information on a thickness of the laminated body before performing the annealing process on the laminated body; and when the before-annealing lamination thickness information does not satisfy a before-annealing criterion which is predetermined, adjusting a lamination condition of the electromagnetic steel plate such that the before-annealing lamination thickness information satisfies the before-annealing criterion.

A rotor includes magnets, and magnet holes each of which includes an opening extending in a radial direction in plan view, penetrates a rotor core in the axial direction, and includes the magnet located therein. A magnetic pole surface of the magnet opposes a circumferential direction. The rotor core includes first thin plate cores and second thin plate cores. The first thin plate cores include an annular first inner plate, first outer plates on a radially outer side of the first inner plate and arrayed side by side in the circumferential direction, first inner connecting portions connecting the first inner plate and the first outer plate, and a first outer connecting portion that is on a radially outer side of the first outer plate and connects the adjacent first outer plates in the circumferential direction.

A motor includes a stator and a rotor provided inside the stator. The rotor includes a rotor core having a magnet insertion hole and two permanent magnets disposed in the magnet insertion hole. The rotor core has a first magnet holding portion disposed between the two permanent magnets and holding the two permanent magnets, an opening disposed on an inner side of the first magnet holding portion in a radial direction of the rotor core, and a center hole disposed at a center of the rotor core in the radial direction. A distance from the opening to the magnet insertion hole is shorter than a distance from the opening to the center hole.