Abstract: A remote-controlled dynamoelectric machine maintenance vehicle that can fit and travel within the air gap between a stator and rotor of a dynamoelectric machine. The maintenance vehicle has an effectuator that can remotely attach to an adjustable wedge within a coil slot of the stator and tighten the wedge in position and then move on to repeat the process until all the wedges on the stator are secured.

Abstract: An apparatus for producing an electronic inductor includes a coil winder, a locator of inductor, and a spot electric welder. The coil winder includes a brushless DC motor, a single chip for controlling the DC brushless motor and a digital display screen. Locator of inductor is connected to a rotational axis of the DC motor of the coil winder via a connecting pole. Because the apparatus has multi-function, it can accomplish winding the coil, locating, removing the painting, welding and testing the electrical characteristic at the same time and much of the manual operation is replaced by the apparatus, not only the productivity is improved greatly, but also the product quality is ensured.

Abstract: An apparatus for manufacturing an electric motor having a laminated core structure formed by a plurality of core plates made of rolled material of electromagnetic sheet steel. The core plates are manufactured by punching rolled electromagnetic sheet steel in a die set. The rolled electromagnetic sheet steel is displaced angularly relative to the die set. The core plates have rolling directions of the electromagnetic sheet steel angularly displaced by a machine angle determined in accordance with the number of slots or poles provided in the laminated core structure so that a phase difference of cogging torques produced by magnetic anisotropy of the core plates is substantially 180°.

Abstract: Disclosed herein is a jig for assembling a rotor. The jig includes an upper jig part, a lower jig part, a support plate, a guide jig part, and a spring. The upper jig part has a pressure protrusion for press-fitting a rotating shaft, and applies pressing force to the rotating shaft. The lower jig part supports a rotor casing in a direction which is opposite the acting direction of the pressing force. The support plate is mounted to the lower jig part, and supports the rotor casing in a direction which is opposite that of the force for press-fitting the rotating shaft. The guide jig part supports the rotor casing in a direction which is opposite that of reaction force generated in the rotor casing by the support plate. The spring elastically biases the guide jig part towards the rotor casing.

Abstract: The invention relates to a device for assembling, by screwing, a drive member, such as a drive pulley, with a shaft intended to be coupled to the rotor of a rotating electrical machine, the device including an additional, welded connection. According to the invention, this method of producing the assembly device is characterized in that the drive member screwed onto its shaft in the vertical position is welded from below. The invention can be used for rotating electrical machines, such as an alternator or a starter-alternator of a motor vehicle.

Abstract: A tool and method for winding and forming a field coil for field assembly, such as a stator, includes separable tool halves defining a winding cavity therebetween. The winding cavity receives magnet wire that is wound therein, such as by rotating the tool or a winding nozzle. The magnet wire generally conforms to the shape of the winding cavity such that when the tool halves are separated, a field coil having a net shape is produced. Once the magnet wire is sufficiently deposited within the winding cavity, wires of the coil may be bonded together either through a resistive heating process such as by passing an electrical current through the coil or through other heating or chemical bonding methods to thereby maintain the net shape of the field coil once it is removed from the tool.

Abstract: It is an object of the invention to provide a technique for easily installing many turns of a coil winding on a stator. Representative method for manufacturing a motor includes preparing the coil wound into a ring-like form and tied, preparing the split core such that the spacing between the pair pole pieces in the circumferential direction of the split core corresponds to the inner dimension of the coil in the circumferential direction of the split core, inserting the tied coil into the two coil receiving parts through the openings and then, deforming the split core such that the spacing between the pair pole pieces is increased to be longer than the inner dimension of the coil.

Abstract: The invention is characterized in that in a motor rotor constituted by a motor shaft (30), a permanent magnet (31) surrounding the motor shaft (30) around an axis, a pair of end rings (32, 32) surrounding the motor shaft (30) around the axis and pinching the permanent magnet (31) from both sides in an axial direction, and a hollow cylindrical outer sleeve (33) surrounding the permanent magnet (31) and a pair of end rings (32, 32) in a fastening state around the axis, one end portion or both end portions of the outer sleeve (33) protrudes in the axial direction than an end surface of the end ring (32). A rotating balance correction is executed by pruning away a part of the protruding portion.

Abstract: According to a nozzle winding method of causing a nozzle (41) to pass between adjacent magnetic poles (12) and rotating the nozzle (41) around the magnetic pole (12), winding is carried out until the rotating nozzle (41) interferes with wound coils (201 to 242), so that a high space factor is obtained. Thereafter, according to a cam winding method, winding is carried out in a space remaining in a slot while rotating the nozzle (41) in an area not interfering with the coils (201 to 242) in the slot, thereby achieving winding with a high space factor of coils in the entire space of the slot.

Abstract: A method for assembling an electric machine is provided. The method includes providing a rotor having a cavity formed therein. At least one contoured recess is formed in a portion of the cavity. A wedge is inserted into the cavity. The wedge includes at least one contoured protrusion that is configured to mirror the at least one contoured recess of the cavity. The wedge is inserted such that the at least one contoured protrusion is positioned within the at least one contoured recess to facilitate positioning the wedge within the cavity. The at least one contoured protrusion and the at least one contoured recess are shaped to facilitate minimizing stresses within the rotor and the wedge.

Abstract: A modular “quick-form” tooling system and stator bar form set-up method is provided for reconfigurably mounting various stator bar bending/forming tool modules that are used to produce custom bends and curvatures in a length of stator bar stock. At least one stator bar support structure is provided having a support surface formed with an array of tool location alignment holes that allow a variety of different bend-forming tooling modules to be positioned relative to each other in a manner that will define the shape of a generator stator bar during a bending/forming process.

Abstract: A device for positioning and affixing magnets on a magnetic yoke member of an electric motor includes: a nonmagnetic support for receiving the magnets; a magnetic element for holding the magnets in position on the nonmagnetic support arranged on the other side of the nonmagnetic support with respect to the magnets, the attraction exerted by this element on the magnets greater than that exerted by the magnetic yoke member during positioning of the device with respect to the yoke; a device for varying the magnetic forces present, whereby the magnetic attraction of the magnetic yoke member and/or the magnetic element on the magnets may be varied such that the magnetic force of attraction exerted by the yoke on the magnets becomes greater than that exerted by the magnetic element on them, thus provoking transfer of the magnets to the yoke.

Abstract: An electric motor includes carbon brushes (5) disposed in a holder (6) that are pressed by means of a spring force (7) in a radial direction against a jacket face of a cylindrical collector (4) that is fixed to an armature shaft (2) of the motor. The holder (6) for the carbon brushes (5) can be removed from the motor with little effort as a result of a provision of covering means (11, 12) that cover a pivot bearing (3) of the armature shaft (2) to protect it against the entry of dirt on a side of the covering means (11, 12) facing the holder (6) for the carbon brushes (5), provided with one or more chamfers (14, 15) in such a way that the carbon brushes (5) slide over the covering means (11, 12) as the holder (6) is being pulled off and that the carbon brushes (5) thereby are thrust radially outward counter to the spring force (7).

Abstract: A tool and method for winding and forming a field coil for field assembly, such as a stator, includes separable tool halves defining a winding cavity therebetween. The winding cavity receives magnet wire that is wound therein, such as by rotating the tool or a winding nozzle. The magnet wire generally conforms to the shape of the winding cavity such that when the tool halves are separated, a field coil having a net shape is produced. Once the magnet wire is sufficiently deposited within the winding cavity, wires of the coil may be bonded together either through a resistive heating process such as by passing an electrical current through the coil or through other heating or chemical bonding methods to thereby maintain the net shape of the field coil once it is removed from the tool.

Abstract: Stator designs have wide-mouth slots between adjacent poles. Wire coils with high slot fill conductivity are formed around the poles. In some designs, the wire coils are wave wound around the poles. Thick bar conductors can be used for making the wire coils. The wire coils may be inserted using nozzle dispensers or transferred from a pre-form mandrel. In other designs, the wire coils are pre-formed on transferable pockets that are then mounted on the poles. Optional pole extensions or shoes can be attached to the stator poles after the wire coils are formed around the poles.

Abstract: A laminated iron core includes a plurality of stacked iron core pieces punched out from a thin steel sheet material, each iron core piece including a plurality of slot holes for receiving coil windings. At least one electrically insulating sheet piece is stacked on an outer surface of a lowermost iron core piece. The electrically insulating sheet pieces include a spindle hole and a plurality of slot holes which have a substantially similar configuration to, but are smaller than, the slot holes of the iron core pieces whereby edges of slot holes of electrically insulating sheet pieces extend outwardly beyond edges of slot holes of iron core pieces. Burrs formed at edges of slot holes of iron core pieces are covered with edges of slot holes of electrically insulating sheet pieces so that a coil can be wound safely without directly contacting the burrs.

Abstract: In certain example embodiments, a shipping comb for assembling a disk drive is provided. The shipping comb has a comb block which includes a locking portion having a comb pin hole formed therein, at least one spacer, and a connecting beam to connect the locking portion and the at least one spacer. A comb pin is received in the comb pin hole of the locking portion. The comb pin includes at least two engaging portions. A controlling system has a comb latch selectively engagable with the at least two engaging portions so as to control the comb pin to move in the comb pin hole. In certain example embodiments, a method for assembling a disk drive using the shipping comb is provided.

Abstract: A tool is provided for driving a slide or wedge within a slot of an armature or field of a dynamoelectric machine. The armature or field includes a core, and the core includes one or more vent slots for facilitating ventilation of the armature or field. The tool includes a drive for applying a driving force, and a push block is connected to the drive. At least one guide rail is configured to cooperate with the push block. The drive operates on the push block to drive a slide or wedge. The at least one guide rail reduces deflection or skew of the push block during a driving operation.

Abstract: A temporary interconnection element to be installed between the rotor and the stator of a bearingless electric machine, for example during its transport, storage or assembly is described herein. The interconnection element is so designed that the rotor may be secured to an external assembly, such as for example the shaft of an internal combustion engine, before the element is removed from its interconnection position.

Abstract: A tool is disclosed for driving a slide under a wedge within a slot of an armature or field of a dynamoelectric machine. The tool comprises a frame including a pair of elongated rail members; a force application block located between the rail members; a drive connected to the frame, substantially intermediate opposite ends of the frame; a lead screw threadably engaged at one end with the force application block and connected at an opposite end to the drive such that the drive rotates the lead screw when actuated. Rotation of the lead screw causes axial movement of the force application block. The armature or field includes a core, and this core may have one or more vent slots for facilitating ventilation of the armature or field. A slot plate for locating the tool relative to the slide is present, and a portion of the slot plate extends into one or more vent slots. The slot plate establishes a reaction point for forces applied by the force application block to the stator slide.

Abstract: A method of installing a rotor assembly in a generator stator including a central bore is provided. The method includes coupling at least one of a first rotor section and a second rotor section of the rotor assembly to a conveyor such that at least a portion of the rotor assembly is supported by the conveyor. The method also includes moving the rotor assembly into position within the stator bore using the conveyor.

Abstract: A stator bar installation fixture and method for installing stator bars into specific stator core slots within a stator core of rotating electrical equipment. The stator bar installation fixture includes rotating mechanisms, rotatingly fixed at each end of the rotating electrical equipment, for supporting and controlling an angular positioning of a stator bar insertion mechanism relative to the stator core. The stator bar insertion mechanism supports a stator bar within the stator core, angularly locates a stator bar in alignment with the specific stator core slot, and inserts the stator bar into the specific stator core slot.

Abstract: Method and apparatus for pre-forming insulated conductors for motor rotors and stators for use in a next process in forming motor rotors and stators. In accordance with the full exemplary process, insulated rectangular cross-section wire is received from a spool, straightened, stripped over a predetermined length, fed to a bender, cut to length and then bent into the desired hairpin shape and placed on a feeder for the next process. The method and apparatus may be fully automatic, including automatically adjusting itself as required to make hairpin shaped conductors of different lengths, each length having its free ends stripped over a desired length. The method and apparatus for bending, as well as other methods and apparatus disclosed, may be used alone or in other combinations.

Abstract: The current invention provides a stepping actuator, achieving large range up to ±35 ?m with low operating voltages of 15V or lower and large output forces of up to ±110 ?N. The actuator has an in-plane-angular deflection conversion which allows achieving step sizes varying from few nanometers to few micrometers with a minor change in the design. According to certain embodiments of the invention, the stepping actuator comprises a geometrical structure with a displacement magnification ratio of between 0.15 and 2 at operating voltages of 15V or lower. The present invention also provides a method for forming such stepping actuators.

Abstract: An apparatus produces a stator in which grooves are provided at the inner or outer periphery in mutually spaced relationship to receive a stator winding. The stator thus produced may be used in a ring generator for a wind power installation. In order to provide a stator having a winding, in which the susceptibility to trouble as a consequence of the high loading on the generator is substantially reduced, the stator winding is wound without interruption continuously throughout.

Abstract: A method of making a wound field for a brushless direct current motor, direct current generator, alternating current motor or alternating current generator, includes providing a base mold having an engagement face with at least one movable end turn form. A number of distinct phases is determined and at least one strand of conductive material is wound around at least one movable end turn forming tool per distinct phase. One conductive coil is created from each strand of conductive material for each distinct phase. Each conductive coil is formed into a configuration that indicates the number of poles required. Each conductive coil is then placed onto an insertion instrument. The insertion instrument and each conductive coil are inserted into a stator core. The insertion instrument is removed from the stator core, and the stator core is installed into one of the aforementioned motors or generators.

Abstract: This invention pertains to an economical method of easy conversion of any internal combustion fueled vehicle into a fuel saving plug-in hybrid electric vehicle (PHEV) by an add-on kit, without replacing the engine and with a minimal modification of the vehicle body. The converted vehicle substantially saves fuel as compared to the vehicle before this conversion.

Abstract: The present invention comprises a method and apparatus for installing a stator core, or portions thereof, into a power generator frame 2 that comprises assembling the stator core inside of a container 60, and then moving the container to the power generator 1. The container 60 is horizontally aligned with the power generator 1, and the stator core is transferred from the container to the power generator.

Abstract: Devices and methods are provided for a rotor assembly and an electric motor. One embodiment for a rotor assembly includes a first rotor including a first interface surface and a second rotor including a second interface surface corresponding to the first interface surface. Also, the first rotor is positioned with the first interface surface in direct physical contact with the second interface surface of the second rotor.

Abstract: In accordance with one embodiment, the present technique provides an apparatus for assembling a rotor. The exemplary apparatus includes a base that has a central aperture and a seating surface for receiving the rotor. An arbor then extends through the central aperture, the arbor having a longitudinal axis that is substantially orthogonal to the seating surface, and including threaded ends opposite with respect to one another. The exemplary apparatus also includes at least one member of a family of fixtures coupleable to the arbor, the family including a pressure fixture that has first and second piston assemblies disposed at diametrically opposite locations to one another, the family also including a support fixture coupleable the arbor and having members extending axially therefrom, the members being configured to support securing members of the rotor.

Abstract: The present invention provides a method for producing a stator assembly. The method initially includes providing an assembly mandrel having a generally cylindrical hub and a generally annular base circumscribing a terminal end portion of the hub. A first end ring and a stator shell are installed around the mandrel hub and onto the mandrel base. Thereafter, a plurality of poles are disposed on top of the first end ring and in a generally cylindrical pattern between the stator shell and the mandrel hub. A second end ring is disposed around the mandrel hub and on top of the plurality of poles. A plurality of stator shell tabs may then be bent in a radially inward direction to axially retain the first and second end rings.

Abstract: A method of making a wound field for a brushless direct current motor, direct current generator, alternating current motor or alternating current generator, includes providing a base mold having an engagement face with at least one movable end turn form. A number of distinct phases is determined and at least one strand of conductive material is wound around at least one movable end turn forming tool per distinct phase. One conductive coil is created from each strand of conductive material for each distinct phase. Each conductive coil is formed into a configuration that indicates the number of poles required. Each conductive coil is then placed onto an insertion instrument. The insertion instrument and each conductive coil are inserted into a stator core. The insertion instrument is removed from the stator core, and the stator core is installed into one of the aforementioned motors or generators.

Abstract: A clamp for attaching a clip to an end of a stator bar including: an anchor adapted to fit into an open end of the clamp; a bracket having a first leg extending radially from the anchor and a second leg substantially perpendicular to the first leg, wherein the second leg has a distal end with a pivot point; at least one alignment post on an inside surface of the second leg; a lever arm pivotably attached to the pivot point on the second leg of the bracket, the lever arm further including a lip on a first end of the arm and adapted to releasably engage an edge of a cover to clip, and an adjustment screw threaded through the lever arm and having a first screw end abutting an outside surface of the second leg of the bracket, wherein turning the screw pivots the lever arm and moves the lip towards or away from the cover.

Abstract: In a method for assembling an electric compressor which contains a rotor having built-in magnets, magnets in a pre-magnetization state are inserted into a plurality of slots of a magnetizing jib made with a nonmagnetic material. After magnetizing the magnets, the magnetizing jib is fitted to the rotor to have the magnets transferred into magnet slots. A magnetizing method and an assembly method for implementing high reliability electric compressors at low manufacturing cost is implemented.

Abstract: A device to press a rotatably supported shaft of a rotor of a spindle motor for a hard disk drive into a shaft receiving portion of an associated stator housing by means of a first pressing tool acting on the rotor and a second pressing tool acting on the stator housing. A first aligning apparatus for the rotor and a second aligning apparatus for the stator housing are provided. The first and second aligning apparatuses are formed in such a way that they guide the rotor by means of a rotor carrier and the stator housing by means of a stator carrier. The rotor carrier and the stator carrier are exactly aligned with respect to each other during the pressfitting process. The first pressing tool has a first pressing element acting on the shaft of the rotor that is independent of the first aligning apparatus and the second pressing tool has a second pressing element acting on the stator housing that is independent of the second aligning apparatus.

Abstract: The present invention discloses an apparatus for fixing an inner stator (320) of a motor of a reciprocal compressor and a method therefor. The apparatus for fixing the inner stator (320) of the motor of the reciprocal compressor includes a front frame, a cylinder inserted into and coupled to the front frame, an outer stator supported by the front frame (210) in a contact state, an inner stator (320) formed in a cylindrical shape and inserted onto the outside circumferential surface of the cylinder (410) with a predetermined interval from an inside diameter of the outer stator (310), a mover (330) inserted between the outer stator (310) and the inner stator (320), and coupled to a piston (420) inserted into the cylinder (410), and a stator fixing means incorporated with the front frame (210) to pass through the cylinder (410) or the inner stator (320) in the longitudinal direction, for supporting and fixing both sides (213,215) of the inner stator. Here, the apparatus is fabricated by using casting.

Abstract: A starter apparatus is disclosed. The starter apparatus includes a housing, a motor disposed within the housing, the motor having an armature shaft, and a planetary gear train disposed within the housing and in operable communication with the armature shaft. The planetary gear train includes a ring gear, a carrier shaft in operable communication with the planetary gear train for outputting a torque of the armature shaft transferred through the planetary gear train, and a dampener in exclusive connection between the ring gear and the housing.

Abstract: The present invention comprises a method and apparatus for installing a stator core into a power generator 1 that comprises assembling the stator core inside of a container 60, and then moving the container to the power generator. The container is horizontally aligned with the power generator, and the stator core is transferred from the container to the power generator.

Abstract: A stator manufacturing device including a winding unit for forming a winding coil made up of a plurality of unipolar coils formed by winding wire, an insertion unit for receiving the winding coil from the winding unit and inserting the winding coil into a stator core, a shaping unit for shaping an outline of the winding coil that has been inserted into the stator core, and a transfer unit that is movable towards the insertion unit and the shaping unit, such that, in a state of holding the stator core, the transfer unit, by relatively moving to the insertion unit, moves the winding coil into a position for insertion into the stator core, and, by moving relative to the shaping unit, forms an outline of the winding coil.

Abstract: Apparatus and methods for forming wire coil leads that depart from wire coils inserted into a dynamo-electric machine component are provided. A plurality of wire coils may be received on an insertion tool. A wire lead may be anchored at a location on the insertion tool. A wire coil corresponding to the wire lead may encircle the location in a plane of the insertion tool. In accordance with the present invention, none of the plurality of wire coils may surmount a first portion of the wire lead anchored at the location. In some embodiments, a template for winding the wire coils may be provided that has a seat portion on the underside of the template. The seat portion may receive a wire lead such that the lead is aligned with the anchoring location on the insertion tool.

Abstract: A sealed type motor-driven compressor includes a cylindrical motor housing and an annular stator core fastened to the interior of the motor housing. A method of assembling the compressor includes fastening the stator core to the motor housing by mechanically deforming at least one of the motor housing and the stator core. It is thus possible to set the fastening interference between the motor housing and the stator core to a sufficiently great level for suppressing loosening of the stator core with respect to the motor housing, which may otherwise be caused by a relatively high pressure produced by refrigerant gas.

Abstract: A method and apparatus for compressing the endplate of an electric generator to relieve the restraining force on a plurality of key blocks that restrain the endplate in compression. The method includes simultaneously applying independent compressive loads at each of the key block locations to the endplate to relieve pressures on the key blocks and removing the key blocks so the endplate can be removed.

Abstract: A modular “quick-form” tooling system and stator bar form set-up method is provided for reconfigurably mounting various stator bar bending/forming tool modules that are used to produce custom bends and curvatures in a length of stator bar stock. At least one stator bar support structure is provided having a support surface formed with an array of tool location alignment holes that allow a variety of different bend-forming tooling modules to be positioned relative to each other in a manner that will define the shape of a generator stator bar during a bending/forming process.

Abstract: The present invention provides a method for the horizontal stacking of laminations 10 and donuts to form a stator core. A stator generator frame 2 has multiple keybars 6 that run the axial length of the frame. The laminations 10 have grooves 12 there-in that engage the keybars to provide a secure fit of the laminations to the generator frame. By extending two or more of the keybars 6, these extensions 7 may be used as rails on which the laminations may be horizontally inserted into the stator frame.

Abstract: In manufacturing a stator coil for a rotary electric machine, a U-shaped segment is deformed at the turn portion thereof so that one of two straight portions thereof moves against the other one in a direction generally perpendicular to a borderline which connects two bordering points between the straight portions and the turn portion. The segment is twisted by moving the straight portions apart from each other. The segment is inserted into slots formed in a stator core so that the turn portion and end portions of the straight portions protrude from both axial end surfaces of the stator core. The end portions are folded in the circumferential direction of the stator core. The tips of the end portions are connected to tips of other segments.

Abstract: A stator for a motor includes a stator core, an insulator, and coils. The stator core includes an annular portion and teeth, which extend radially from the annular portion. The stator core is divided into core segments in the circumferential direction. Each core segment has an arcuate portion and one of the teeth, which extends from the arcuate portion. The insulator insulates each coil wound around one of the teeth from the stator core. The insulator includes coupling portions at positions corresponding to the circumferential ends of the arcuate portions. Each coupling portion couples the adjacent core segments to be rotatable relative to each other. The insulator facilitates manufacture of the stator.

Abstract: A method of forming a winding core for an electric motor includes providing a hollow jig having a guide, sliding plates, each having a guide and a central opening, onto the guide in the jig where the guides mate, and pressing a shaft into the central opening of the plates. The plates are then compressed to form a lamination and secured in compression by a lock nut on the shaft.

Abstract: An automatic assembly machine includes a basis (10), a sliding device (30) horizontally movably attached on the basis for supporting a fan (40) thereon, a tube (27) fixed to the basis for receiving a plurality of bearings (28) therein, a diversion station for provisionally holding one bearing thereon, a mounting device (70) vertically movably attached to the basis, a horizontal driving device (60), a vertical driving device (80), and a control device (90) for controlling periodical movement of the horizontal and vertical driving devices. In one period, the vertical driving device drives the mounting device to catch the bearing from the diversion station and then the horizontal driving device drives the sliding device and the diversion station to move to allow the diversion station to receive another bearing from the tube and the mounting device to mount said bearing to the fan upon driven of the vertical driving device.

Abstract: A centering device for use with a cutting die in a mold. The die is supported by a sleeve, which rotates about the axis of the die. The device comprises at least two cavities formed on the side surface of the sleeve, which are spaced apart along a same circumference, and at least one wedge-like element that is fastened to the mold and can be alternatively engaged in one of said cavities of the sleeve, with a conical coupling, in order to lock the sleeve after a rotation of the same.

Abstract: A coil forming apparatus includes a twisting formation unit that twist-forms a predetermined number of U-shaped conductor segments. The twisting formation unit includes a first twisting formation jig composed of a first inside ring and a first outside ring and a second twisting formation jig composed of a second inside ring and a second outside ring. Each of the first and second inside rings has the same number of circumferentially disposed holding slots as the stator slots to hold one of each pair of straight portions. Each of the first and second outside rings has the same number of circumferentially disposed holding slots as the stator slots to hold the other of each pair of straight portions of the U-shaped conductor segments. The first and second inside rings and the first and second outside rings are coaxially coupled to shift relative circumferential position between the inside rings and the outside rings by a predetermined angle to twist the turn portions of the U-shaped conductor segments.