Abstract: A motor includes an armature arranged radially outside a rotor magnet, and a casing configured to fix the armature and hold upper and lower bearings configured to rotatably support a shaft at a radial center thereof. The armature includes a stator core, an insulator arranged to cover the stator core, coils each of which is defined by a conducting wire wound around a separate one of magnetic pole teeth with the insulator intervening therebetween, and passage lines each of which is arranged circumferentially between adjacent ones of the magnetic pole teeth to electrically connect one of the coils and another one of the coils with each other. The insulator includes magnetic pole tooth insulating portions arranged to cover a separate one of the magnetic pole teeth; and a core back insulating portion integral with each magnetic pole tooth insulating portion.

Abstract: A stationary portion of a motor includes resin bodies including an inner and outer resin portion arranged between a tooth and a coil and between the tooth and an insulator. The outer resin portion covers circumferentially outer sides and axially outer sides of the coil. The inner and outer resin portions are continuous with each other through a connecting resin portion. The insulator includes an opening portion arranged to extend along circumferential side surfaces of the tooth. The inner resin portion is arranged to contact the circumferential side surfaces of the tooth and a conducting wire in the opening portion. Heat generated in the coil is transferred to the tooth through the resin body such that a large area of a path along which the heat is transferred from the coil to the tooth is secured.

Abstract: A motor includes a shaft, a rotor magnet, an armature, an upper bracket, a lower bracket, and a fixing member. An insulator includes magnetic pole tooth insulating portions, each of which covers a separate one of magnetic pole teeth, and a core back insulating portion configured to cover at least portions of upper and lower end surfaces of a core back. A stator core includes a fixing member arranging portion. The core back insulating portion includes a core back insulating projecting portion configured to project in an axial direction away from a surface covering the core back, and including a radially inner surface located radially inward of a radially inner end of the fixing member arranging portion. The core back insulating projecting portion includes a cut portion at a position radially opposed to the fixing member.

Abstract: The present invention relates to a stator for a motor including: a stator core having an annular back yoke and a plurality of teeth; an upper insulator having an annular body portion formed correspondingly to the back yoke of the stator core and a plurality of teeth insulation portions formed correspondingly to the teeth of the stator core so as to cover the upper sides of the teeth of the stator core; a lower insulator having an annular body portion formed correspondingly to the back yoke of the stator core and a plurality of teeth insulation portions formed correspondingly to the teeth of the stator core so as to cover the upper sides of the teeth of the stator core; a plurality of insulation films each adapted to be inserted into the slot to cover the side of the stator core exposed to the inside of the slot between the upper insulator and the lower insulator; and coils adapted to be wound on the teeth of the stator core enclosed by the upper insulator, the lower insulator and the insulation films.

Abstract: A motor includes a stator with a bobbin. The bobbin has a lower end winding portion, a head part retainer portion that retains a head part of a winding, and a control portion disposed between the lower end winding portion and the head part retainer portion. A head part retainer surface formed on a pump part side of the head part retainer portion and an end face formed on a pump part side of the control portion are positioned on the same plane and on a pump part side relative to a winding retainer surface that is formed on a pump part side of the lower end winding portion. Thus, when the winding is wound in layers onto the winding retainer surface of the bobbin, collapsing of a middle part of the winding onto the head part of the winding is prevented.

Abstract: A slot liner is configured for association with a tooth of an electro-dynamic machine core having an annular rim and circumferentially spaced teeth radially extending from the annular rim. The slot liner includes sidewalls configured to line circumferential surfaces of the tooth, first and second tabs formed by bends in the sidewalls, the first tab being configured to line a portion of the annular rim adjacent to the tooth and the second tab being configured to overlap with a tab of an adjacent slot liner and a retainer configured to retain the sidewalls against a radially inward portion of the tooth.

Abstract: Embodiments of a gas turbine engine actuation system are provided, as are embodiments of a high temperature actuator and methods for the manufacture thereof. In one embodiment, the gas turbine engine actuation system includes an actuated gas turbine engine component and a high temperature actuator, which has a rotor mechanically linked to the actuated gas turbine engine component and a stator surrounding at least a portion of the rotor. The stator includes, in turn, a coil support structure having a plurality of spokes extending radially therefrom. A plurality of pre-formed electromagnetic coils is circumferentially distributed about the coil support structure. Each of the plurality of pre-formed electromagnetic coils is inserted over at least one of the plurality of spokes in a radial direction. The stator further includes an inorganic dielectric material in which each of the plurality of pre-formed electromagnetic coils is at least partially embedded.

Abstract: A high-temperature insulation assembly for use in high-temperature electrical machines and a method for forming a high-temperature insulation assembly for insulating conducting material in a high-temperature electrical machine. The assembly includes a polymeric film and at least one ceramic coating disposed on the polymeric film. The polymeric film is disposed over conductive wiring or used as a conductor winding insulator for phase separation and slot liner.

Abstract: The invention relates to a winding carrier (1) for the defined application of a coil winding, comprising: a winding section (2) for placing onto a cylindrical tooth component; a groove structure (3), which is arranged in at least one region of the winding section and extends transversely to the winding axis in order to receive a winding wire; wherein the groove structure (3) has a cross section having two mutually opposite, preferably flat side faces (7), which taper in the direction of a bottom face (6) of the groove structure (3).

Abstract: A coil strand is wound on an insulator to produce a divided core member, and then the divided core member is placed on a table. While the table rotates about its axis, ends of the coil strands are inserted into lead end holding grooves, which are defined in a surface of the insulator on an outer circumferential edge of a stator and which extend along a circumferential direction of the stator.

Abstract: A bar wound stator includes a stator core defining a plurality of slots. Bar-type conductors are disposed within each slot. Each slot includes a slot liner and an insulator cap. Each slot liner includes an end portion disposed against an inner wall surface, and side portions disposed against a first wall surface and a second wall surface respectively. Each insulator cap includes a base portion disposed against an outer wall surface, and side portions disposed against the first wall surface and the second wall surface respectively. The side portions of the insulator cap in each slot overlap the side portions of the slot liner in each slot along the first wall surface and the second wall surface respectively. Each slot includes a recessed feature in each of the first wall surface and the second wall surface to accommodate the overlapping side portions of the insulator cap and the slot liner.

Abstract: A pole separator insert is employed in a stator assembly of an electric machine to separate winding coils installed within circumferentially distributed slots of a stator core. The pole separator insert comprises first and second insulating tabs connected by first and second legs. The first and second insulating tabs are disposed between adjacent winding coils of a single phase, at opposite ends of the stator core. The first and second legs are disposed through adjacent circumferentially distributed slots of the stator core.

Abstract: A stator assembly comprises a stator defining S slots. First and second windings are arranged in each of the S slots. The two windings have a width in a radial direction and a thickness in a direction perpendicular to the radial direction. A ratio of the width to the thickness is between 3.0:1 and 4.5:1.

Abstract: An insulation system and method are disclosed for insulating formed coils of electrical machines, such as motors and generators. The system and methods additionally apply to refurbishing of the formed coils. The system includes strand/turn insulation that may include one or more layers of different materials, depending upon the dielectric requirements. A ground wall insulation is applied over the group of turns. The coil may be sized in a slot cell section. Additional insulation layers are provided, including an armor layer. The various insulation layers may each be applied in one continuous wrap. The resulting system is highly adaptable to different machine designs and ratings, and affords superior resistance to degradation.

Abstract: A mounting structure for slot paper in a motor stator. The slot paper is embedded in stator slots and includes a paper bottom, a paper side, and a paper front. A lug boss is protruded between two adjacent tooth block segments and protrudes from the inner wall of an outer ring. Two ends of the slot paper extend out of each stator slot. Two ends of the paper bottom are locked between the lug bosses respectively arranged on the upper end insulator and the lower end insulator. One end of each tooth block segment is provided with a clip slot and the paper front near the opening is embedded therein. The structure is simple, has a precise slot paper positioning function, does not occupy space of the stator slot, maximizes the slot filling ratio of the slots, and thus improves the overall performance of the motor.

Abstract: A coil fixing device capable of accurately positioning and fixing a coil to a slot of a stator core of an electric motor, and an electric motor having the fixing device, while not using adhesive and having a structure not affecting the characteristic of the electric motor. A positioning member of the fixing device has a coupling member positioned at an axial end of the stator core; a plurality of protruding portions connected to the coupling member at the same angular intervals as the coils, each protruding portion radially inwardly extending from the coupling member; and a latching portion connected to a front end of each protruding portion, the latching portion extending from the front end of each protruding portion in a direction across an extending direction of the protruding portion.

Abstract: An object is to provide a rotating electric machine offering a high output and high efficiency by balancing inductance of each phase even if a stator is used in which stator windings of different phases are disposed in a slot of a stator core in a three-phase winding. A stator 5 includes a stator core 6 having a plurality of slots arrayed circumferentially and opening to an inner peripheral surface and a stator winding 7 wound in each of the slots. The stator winding 7 is divided into at least two for each phase (7U-A, 7U-B, 7V-A, 7V-B, 7W-A, 7W-B). After insertion of the stator core 6, the stator winding of each phase is connected in parallel or in series. The stator winding of each phase is disposed in slots such that combined inductance of different phases is equalized.

Abstract: An insulator for a stator assembly includes at least a first insulator adapted to be mounted to the stator core and structured to insulate the stator core from the coils. The at least one insulator includes structure to perform at least one additional function. For example, the structure may include a support member to support and/or locate the PCBA on the stator core, a wire guide to guide cross-over wires that form a connection between coils, and/or positioning structure to precisely position the PCBA with respect to the coils.

Abstract: A compressor includes a casing and a motor disposed inside the casing. The motor is welded to the casing at a plurality of weld positions. The motor includes a core, a coil, at least one insulating member and a gap. The core has an annular back yoke portion, a plurality of tooth portions projecting radially inwardly from the back yoke portion and a slot formed between the tooth portions adjacent to each other. The coil is disposed in the slot. The insulating member is disposed in the slot to insulate the coil from the core. The gap is provided between the back yoke portion and the insulating member.

Abstract: The present invention relates to a stator of an alternator, providing an elongated stator body having a plurality of parallel grooves, winding a plurality of wires in the plurality of different grooves, and then rolling the elongated stator body wound with the wires into an annular shape to form an annular stator.

Abstract: The present invention relates to a stator of an alternator, providing an elongated stator body having a plurality of parallel grooves, winding a plurality of wires in the plurality of different grooves, and then rolling the elongated stator body wound with the wires into an annular shape to form an annular stator.

Abstract: A stator includes an annular stator core, a stator winding, and an insulating sheet member. In the stator core, slots are circumferentially arrayed. The stator winding includes conductor segments having oblique portions formed by open end portions being circumferentially twisted. The open end portions are inserted into the slots from one of two axial-direction sides and extend towards another one. The insulating sheet member is interposed between an inner wall surface of the slot and the conductor segment. The insulating sheet member is rolled into a cylindrical shape along the inner wall surface of the slot, and includes an overlapping portion and a slack portion. In the overlapping portion, two circumferential-direction end portions overlap each other. The overlapping portion is disposed on one of two radial-direction sides of each of the slots. The slack portion is disposed on another one of two radial-direction sides of each of the slots.

Abstract: A bobbin is adapted to be mounted to a projection of a stator core of a rotary electric machine and wound with a coil wire. The bobbin includes a back stress generating portion configured to generate a stress acting in a direction opposite to a stress generated when the coil wire is wound around the bobbin.

Abstract: Electric submersible well pumping systems operable in well temperatures of above about 180° C. (356° F.) utilize high temperature electrical insulation. The electrical insulation includes E-base polyimide films or perfluoropolymer TE films on various components. The insulation films are employed around magnet wires that are threaded through slots in the stator. Slot insulation of E-base polyimide or perfluoropolymer TE film surrounds the magnet wires in the stator slots. Sheets of E-base polyimide or perfluoropolymer TE film extend around and between phase loops of the magnet wire at the lower end of the stator. The motor contains a PAO oil having additives to dissipate acid generated by epoxy used in the motor.

Abstract: In a stator bobbin for a drive motor, a bobbin body is coupled to a stator core divided into a number of sections across an entire area of the stator, and a coil is wound on the bobbin body. The trailing portion of the coil wound on the bobbin body is fixed to a fixing slot formed at one side of the bobbin body.

Abstract: The invention relates to a synchronous machine with hybridenergisation, in particular a generator for supplying the electrical system of a motor vehicle, comprising a laminated stator (16) with a multiphase stator winding (18) and a laminated rotor (20) with an energizer winding (29), which together with permanent magnets (24,25) around the rotor periphery, provides the energisation for the machine. According to the invention, favorable electrical and magnetic properties and an improvement in manufacturing conditions of the machine can be achieved, wherein the grooves (40) for the energiser windings (29) are disproportionately enlarged in relation to the groove base (44) and are preferably bell-shaped.

Abstract: A phase separator for an electrical machine includes a first end portion, a second end portion, and a midsection. The midsection connects the first end portion to the second end portion such that the first end portion opposes the second end portion. The midsection is configured for fixing the phase separator in the electrical machine for separating the adjacent phase windings from one another. The first and second end portions are for separating end turns of adjacent phase windings of an electrical machine.

Abstract: An insulating phase separator is used in an electric machine to separate phase windings in a stator assembly. The insulating phase separator includes first and second endturn portions and first and second leg portions. The first and second endturn portions each have a curved outer surface and a tabbed portion located opposite the curved outer surface. The first and second leg portions extend between the first and second endturn portions and are integral with the first and second endturn portions.

Abstract: An electrical coil assembly for use in a flooded electrical machine operating in an electrically conductive and/or chemically aggressive medium, and a method for manufacturing an electrical coil assembly, are disclosed. The electrical coil assembly incorporates an electrical cable coil winding and a magnetic core. The electrical coil winding is wound of electrical cable with dielectric insulation that is also a waterproof molecular barrier and is covered with at least one layer of waterproof adhesive material. The magnetic core is substantially surrounded with a dielectric insulation layer, which is covered with at least one layer of waterproof adhesive material. The combination of dielectric insulation and waterproof adhesive layers provide protection against the ingress of water and accordingly reduce risk of electrical fault and failure of the electrical coil assembly in submerged service.

Abstract: A coil wire for a rotating electrical machine forms a coil body wound on teeth of a stator for the rotating electrical machine and includes an element wire assembly and a covering member. The element wire assembly has a plurality of element wires coated with insulation and bound together. The covering member is an electrical conductive member covering around the element wire assembly and provided with a conductive side surface and a slit. The conductive side surface is a surface with which magnetic flux from the teeth is linked when the coil wire is wound on the teeth. The slit is provided on the conductive side surface along a longitudinal direction of the coil wire, and the slit extends from an inner peripheral side to an outer peripheral side of the coil body in an coil end of the coil body.

Abstract: A rotating electrical machine including a stator core formed by layering electromagnetic steel sheets, a first insulator and a second insulator facing with each other and fitted to the stator from an axial direction of the stator core, and a coil winding formed by resin molding and wound around the first and the second insulators. The first insulator includes a first end portion and a first side wall portion and the second insulator includes a second end portion and a second side wall portion. A gap is formed between the first and the second side wall portions and is positioned at a first end portion side or a second end portion side from a middle position of the length of the stator core in the axial direction and is positioned at a portion of the coil winding where a curvature thereat is larger than that at the middle position.

Abstract: A spacer for supporting conductors in a stator assembly of an electric machine includes a plurality of positioning elements cooperating with various conductors in the specials region of the winding arrangement. The spacer illustratively includes an insulating body formed of an electrically non-conductive material and including surfaces facing axially inwardly for contacting short conductors and crossover pockets for receiving crossover conductors which electrically connect an inner winding set and an outer winding set. The spacer further illustratively includes phase lead pockets facing axially outwardly for receiving a terminal phase lead conductor.

Abstract: An electric motor assembly configured for use in a downhole pumping system includes a number of electrically conductive components that are insulated from fluids, mechanical abrasion, electrical current and electrical grounds using an advanced polyimide film. Preferred polyimide films include poly(4,4?-oxydiphenylene-pyromellitimide) and biphenyl-tetracarboxylic acid dianhydride (BPDA) type polyimide films. Magnet wire, stator laminates, stator coil end turns, motor leads and power cables can all be insulated with the selected polyimide film.

Abstract: A method of spacing a plurality of electrical conductors for carrying electrical current in an electrical machine may include positioning between the electrical conductors an uncured spacer body. The uncured spacer body may include a curable material, and an activatable heat generating material mixed with the curable material. The method may further include activating the activatable heat generating material to heat the curable material to form a cured spacer to thereby space the electrical conductors in the electrical machine.

Abstract: A wire assembly for use in an electric machine is provided. The assembly includes a member and a wire. The wire conducts electrical current. At least a portion of the wire is adapted to be wrapped at least partially around the member. The member defines a periphery of the member. At least a portion of the periphery of the member is conformable when the wire is wrapped at least partially around the member.

Abstract: A ripple spring is provided having one or more conductive layers, and one or more non-conductive layers. The conductive layers and the non-conductive layers are laminated together to form a symmetrical stack of layers. A method is also provided for monitoring the ripple spring. The method includes the steps of providing a ripple spring that holds a winding in place, where the ripple spring is positioned at least partially within a stator slot defined within an electromechanical device. Providing a conductive layer disposed within the ripple spring, and generating signals from the conductive layer, the signals corresponding to at least one aspect of the ripple spring. An analyzing step analyzes the signals to determine the at least one aspect of the ripple spring, wherein the at least one aspect facilitates an identification of faults in the ripple spring.

Abstract: The invention relates to a synchronous machine with hybrid energization, in particular a generator for supplying the electrical system of a motor vehicle, comprising a laminated stator (16) with a multiphase stator winding (18) and a laminated rotor (20) with an energizer winding (29), which together with permanent magnets (24,25) around the rotor periphery, provides the energization for the machine. According to the invention, favorable electrical and magnetic properties and an improvement in manufacturing conditions of the machine can be achieved, wherein the grooves (40) for the energizer windings (29) are disproportionately enlarged in relation to the groove base (44) and are preferably bell-shaped.

Abstract: A motor includes a shaft, an annular rotor magnet, an armature arranged to cover the rotor magnet, an upper bracket fixed to an axial upper portion of the armature, and a lower bracket fixed to an axial lower portion of the armature. The armature includes an annular core-back, a plurality of magnetic pole teeth protruding radially inward from the core-back, an insulator arranged to cover the magnetic pole teeth, and a coil wound around the magnetic pole teeth through the insulator. The insulator includes an annular core-back insulating portion arranged radially outward of the coil and extended axially upward. The upper bracket is fixed by a plurality of fixing members positioned radially inward of an outer circumferential surface of the core-back.

Abstract: An interphase insulating sheet for a rotating electric machine includes a pair of insulating portions and a plurality of bridge pieces. The insulating portions perform interphase insulation between coil ends of coils protruding from both ends of a stator core. Each insulating portion has bridge bases. The bridge pieces are each inserted in one of slots. Each bridge piece extends from a bridge base of one of the insulating portions to a bridge base of the other insulating portion. Each insulating portion has an annular shape having stacked parts that include a bridge base and overlap with each other by a predetermined margin. In the circumferential direction of each insulating portion, the dimension of the stacked parts is set to be less than or equal to the dimension of the bridge pieces.

Abstract: A rotating machine includes a stator including a stator core having a plurality of slots arrayed in the circumferential direction, a plurality of conductors for stator winding wire inserted respectively into the slots, and slot liners comprising a sheet-shaped insulator surrounding the conductors for stator winding wire; and a rotor rotatably arranged concentrically with the stator. In the rotating machine the slots of which are filled with an electrically insulative resin, concavo-convex is formed on both the top and bottom surfaces of the slot liners.

Abstract: An apparatus and method for providing electrical insulation between adjacent end turns at different phases within a stator assembly. In one embodiment, the invention is directed to a stator assembly comprising: a stator core; at least two coils of different phases wound on the stator core through the slots and having an end turn that extends from the stator core; and one or more rigid separator members positioned between adjacent end turns of the coils.

Abstract: A spool carrier has a winding body with a shell having a trapezoidal cross section with two substantially right angles and one acute angle, wherein the spool wire is guided on the obtuse angle edge of the winding body, beginning parallel to the front face edges of the winding body, along the side surface adjoining the obtuse angle edge, around the winding body, to the acute angle edge of the winding body, and guided on the front face from the acute to the obtuse angle edge at an angle to the front face edge, such that it comes to rest on the obtuse angle edge in one winding step directly adjacent to the winding wire of the previous winding, and in one winding step in the next adjacent groove between two windings of the previous layer, or optionally between the flange and the winding of the previous layer.

Abstract: Electric submersible well pumping systems operable in well temperatures of above about 180° C. (356° F.) utilize high temperature electrical insulation. The electrical insulation includes E-base polyimide films or perfluoropolymer TE films on various components. The insulation films are employed around magnet wires that are threaded through slots in the stator. Slot insulation of E-base polyimide or perfluoropolymer TE film surrounds the magnet wires in the stator slots. Sheets of E-base polyimide or perfluoropolymer TE film extend around and between phase loops of the magnet wire at the lower end of the stator. The motor contains a PAO oil having additives to dissipate acid generated by epoxy used in the motor.

Abstract: A DC electric rotating machine, mainly for the starter of an automotive vehicle. The machine includes a stator including a wound structure forming a plurality of poles extending along the circumference of the stator, a rotor, and a set of brushes adapted for the electric supply of the rotor by commutation of the electric current in sections of the rotor. The wound structure of the stator includes a plurality of slots between two central parts of consecutive poles of the stator, these slots being formed in a magnetic body of the stator. At least one of the slots including at least one conducting segment forming a winding of an electrical coil.

Abstract: An electric motor includes one or more separate coil sets arranged to produce a magnetic field of the motor. The electric motor also includes a plurality of control devices coupled to respective sub-sets of coils for current control. A similar arrangement is proposed for a generator. A coil mounting system for an electric motor or generator includes one or more coil teeth for windably receiving a coil for the motor and a back portion for attachably receiving a plurality of the coil teeth. A traction control system and method for a vehicle having a plurality of wheels independently powered by a respective motor. A suspension control system and method for a vehicle having a plurality of wheels, each wheel being mounted on a suspension arm of the vehicle and being independently powered by a respective motor.

Abstract: A slot liner is configured for association with a tooth of an electro-dynamic machine core having an annular rim and circumferentially spaced teeth radially extending from the annular rim. The slot liner includes sidewalls configured to line circumferential surfaces of the tooth, first and second tabs formed by bends in the sidewalls, the first tab being configured to line a portion of the annular rim adjacent to the tooth and the second tab being configured to overlap with a tab of an adjacent slot liner and a retainer configured to retain the sidewalls against a radially inward portion of the tooth.

Abstract: A washing machine with a motor having a structure with improved performance. The washing machine includes a body, a tub disposed in the body, a drum rotatably disposed in the tub, and a motor including a stator coupled to a rear surface of the tub and a rotor rotatably disposed inside the stator. The stator includes a stator core including a core body and a plurality of core teeth extending inward from an inner circumferential surface of the core body in a radial direction of the core body, a first insulator and a second insulator covering both ends of the core body and the core teeth, a coil wound around the core teeth, and a plurality of insulation films disposed between the first insulator and the second insulator to electrically insulate the stator core and the coil.

Abstract: A brushless motor comprising: a rotor; a stator core disposed at a radial direction outside of the rotor, and a stator case. The stator core includes an outer ring shaped section, teeth sections projecting out from the outer ring shaped section toward a radial direction inside, and an inner ring shaped section extending from end portions of the teeth sections. Protruding portions are formed at the outer ring shaped section so as to project toward a radial direction outside and so as to be disposed at even intervals around a circumferential direction of the outer ring shaped section. The stator case is integrated together with the stator core by a plurality of plastic deformation portions formed at an outer peripheral portion of the stator case at locations facing towards the protruding portions, and the plastic deformation portions are disposed at even intervals along a circumferential direction of the stator case.

Abstract: The electric rotating machine has the structure in which, for each one of the slots formed in its stator core, each of the innermost and outermost electrical conductors housed in the slot includes a R-chamfered portion formed in a bent portion thereof projecting outside from the slot and bent along a circumferential direction of the stator core. The R-chamfered portion is located at a radially inner or outer corner of the bent portion at which a side surface of the bent portion on the side being circumferentially bent intersects with a side surface of the bent portion on the radially inner or outer side. The R-chamfered portion is formed of a curved surface having a curvature radius larger than a curvature radius of the other three corners of the bent portion.

Abstract: A rotating electric machine includes a rotor, and a stator that has a stator core and a stator winding. The stator core has a plurality of slots. The stator winding is wound around the stator core as a plurality of electrical conductors is aligned in the radial direction in the slots. The stator has an insulating sheet member that is bent in a rectangular cylindrical shape, and is intervened between the electrical conductor and an inner wall surface of the slot. A length of a bend line formed extending in the axial direction on the insulating sheet member from a reference position in a central section of the insulating sheet member in the axial direction to a tip in the axial direction is configured shorter than a length from the reference position to an end in the axial direction of the sheet member.