A field magnet manufacturing method where a bonded magnet's inner surface press-fitted in a yoke has a certain accuracy irrespective of the accuracy of the yoke's outer circumferential surface. A cylindrical bonded magnet from binding magnet particles with a thermosetting resin is fixed in a tubular yoke of magnetic material. The method includes reheating and softening the bonded magnet after thermal curing; and press-fitting in the bonded magnet after the softening step from a tapered portion on one end side of the yoke to press the bonded magnet's outer circumferential surface against the yoke's inner surface. The press-fitting includes feeding the bonded magnet relatively into the yoke while allowing a relative posture variation between the bonded magnet and the yoke so the bonded magnet's inner surface to be remolded into a shape along the inner surface of the yoke exhibits almost the same accuracy as the yoke's inner surface.

A rotor manufacturing method comprises an arranging step for arranging a rotor core, which is formed by stacking electromagnetic steel plates, to direct the stacked electromagnetic steel plates toward a vertical direction, a guide inserting step for inserting a rod-like guide into a magnet insertion hole formed to extend in the stacked direction of the rotor core after the arranging step, a sheet inserting step for inserting a plurality of sheets from above the rotor core into the magnet insertion hole along different side surfaces of the guide after the guide inserting step, a guide pull-out step for pulling out the guide from the magnet insertion hole after the sheet inserting step, and a magnet inserting step for inserting a permanent magnet between the plurality of sheets within the magnet insertion hole after the guide pull-out step.

A method for manufacturing a polymeric electrical machine includes manufacturing a stator including a laminated stator core and a plurality of windings including winding overhangs; applying a surface treatment to the stator core constructed to reduce defects at an interface between a polymeric material and the stator core and enhance adherence between the polymeric material and the stator core; mounting the stator onto a mandrel; inserting the stator into an electrical machine housing mold; molding an electrical machine housing including a stator band with an integral non-drive end endplate, including overmolding the stator and winding overhangs within the stator band; molding a drive end endplate, including forming polymeric ribs in the drive end endplate and overmolding a metallic structure into the endplate, the metallic structure enhancing mechanical stiffness of the endplate; installing a rotor assembly into the electrical machine housing; and installing the endplate onto the electrical machine housing.

An EC motor is provided having a stator, in which an armature is rotatably supported, the armature including an armature shaft, on which an armature core having a plurality of permanent magnets is held, the armature core being electrically insulated against the armature shaft with the aid of a casting compound, and a balance ring being provided on at least one axial end of the armature core, which is accommodated on the armature shaft by a central recess, a gap between the armature shaft and the central recess of the balance ring being filled with casting compound, and the permanent magnets being held in pockets of the armature core by casting compound.

A manufacturing method of a rotor may be provided with: arranging a magnet and a thermoplastic in a magnet fixing portion of a rotor core including a laminate in which a plurality of metal plates is laminated, the magnet fixing portion including a hole and/or a trench provided in the rotor core and extending along a lamination direction of the laminate; heating the rotor core while rotating the rotor core around a center axis of the rotor core, with the center axis intersecting a vertical direction; and cooling the rotor core to fix the magnet to the rotor core via the thermoplastic while rotating the rotor core around the center axis, with the center axis intersecting the vertical direction.

Exchangeable stator components are selected and exchangeable rotor components are selected to transform a motor from one motor class to another motor class. A motor comprises at least two stator rings, at least two outer rotor rings, a first input, and a second input. The first input comprises an exchangeable stator component selected from a stator component group consisting of a stator spacer ring and an axially magnetized stator magnet ring, the axially magnetized stator magnet ring comprising a solid axially magnetized ring magnet. The second input comprises an exchangeable rotor component selected from a rotor component group consisting of a rotor spacer ring and an axially magnetized rotor magnet ring. The first input and the second input determine a motor class for the motor, the exchangeable stator component being exchangeable for a different exchangeable stator component from the stator component group to manufacture another motor having a different motor class, the exchangeable rotor component being exchangeable for a different exchangeable rotor component from the rotor component group to manufacture another motor having another different motor class.

In a method for producing a rotor including a leak prevention hole formed in a rotor core to prevent leakage of magnetic flux from a permanent magnet; an outer-circumferential-side dovetail groove formed in an outer-circumferential-side inner wall of the leak prevention hole, an inner-circumferential-side dovetail groove formed, opposite the outer-circumferential-side dovetail groove, in an inner-circumferential-side inner wall of the leak prevention hole; and a non-magnetic bridge having both end portions engageable with the dovetail grooves, an external force is applied to bring the outer-circumferential-side inner wall close to the inner-circumferential-side inner wall, the non-magnetic bridge is inserted in the dovetail grooves while keeping the rotor core in an elastically deformed state, and, after inserting, the external force is released.

Downhole tools for earth-boring applications may include a component of a steel material and including a bore. An inner surface defining the bore may be treated with a surface treatment. The surface treatment may include a nitrided region having nitrogen diffused into the steel material and a ceramic material adjacent to the nitrided region; the ceramic material defining the inner surface. Methods of making downhole tools for earth-boring applications may involve exposing a component of the downhole tool to an elevated temperature to heat the component in a nitrogen-rich environment. Nitrogen may be diffused into a steel material of the component and a nitrided region may be formed at one or more surfaces of the component. A ceramic material may be coated on the nitrided region of the component.

A manufacturing method of a rotor for an electric motor is disclosed herein. The rotor may include a rotor core having a through hole that extends along an axial direction of the rotor; a magnet inserted in the through hole; and a sheet disposed between an inner surface of the through hole and the magnet. The method may include inserting the sheet into the through hole such that the sheet extends through the through hole; and inserting the magnet into the through hole while the sheet is pulled at axial ends of the sheet in opposite directions to apply tension to the sheet and press the sheet against the inner surface.

A method of manufacturing a rotor of an electric motor is disclosed. The method includes securing a plurality of permanent magnets to a sheet to form a magnet chain, bending the sheet to engage an inner surface of each permanent magnet with a curved outer surface of an insert mold, wrapping a metallic strip around an outer surface of the sheet to form a yoke of the rotor, and molding a polymeric material over the magnet chain and the yoke to form a cylindrical shell.