ARMATURE WINDING AND METHOD FOR MANUFACTURING SAME

In a multiphase armature winding provided in an armature that constitutes a rotating electric machine and that is configured by conductive wire material, the conductive wire material for each phase includes an assembly of strands having a conductor and an inner insulating layer of insulating material surrounding the conductor, and an outer insulating layer of insulating material surrounding the assembly of strands. The outer insulating layer is peeled off at an end of the conductive wire material. A tip of the conductive wire material at the peeled portion of the outer insulating layer is joined by welding or crimping to form a joint portion. At least a portion other than the joint portion, in the conductive wire material at the peeled portion of the outer insulating layer, is varnished.

TECHNICAL FIELD

The present disclosure relates to an armature winding and method for manufacturing the same.

BACKGROUND

Conventionally, an armature having multiphase armature windings made of conductive wires is known.

SUMMARY

In a multiphase armature winding having a conductive wire material and provided in an armature that constitutes a rotating electric machine, the conductive wire material of each phase includes an assembly of strands having a conductor and an inner insulating layer made of an insulating material covering the conductor, and an outer insulating layer surrounding the assembly of strands and made of an insulating material.

The outer insulating layer is peeled off at an end of the conductive wire material, a tip of the conductive wire material at the peeled portion of the outer insulating layer is joined by welding or crimping to form a joint portion, and at least a portion other than the joint portion, in the conductive wire material at the peeled portion of the outer insulating layer, is varnished.

DETAILED DESCRIPTION

In an assumable example, an armature having multiphase armature windings made of conductive wires is known. When a magnetic flux from a field element interlinks with a conductor that constitutes a wire material, eddy current flows in the conductor and eddy current loss occurs. In order to reduce this eddy current loss, the wire material is provided with an assembly of strands.

There is a concern that the strands gathered at the ends of the conductive wire material may be untied. When the wires are untied, there is a concern that the workability in the manufacturing process of the armature winding will be lowered.

The present disclosure is to provide an armature winding and a method of manufacturing the same that can improve workability in the manufacturing process of the armature winding.

In a multiphase armature winding having a conductive wire material and provided in an armature that constitutes a rotating electric machine, the conductive wire material of each phase includes an assembly of strands having a conductor and an inner insulating layer made of an insulating material covering the conductor, and an outer insulating layer surrounding the assembly of strands and made of an insulating material.

The outer insulating layer is peeled off at an end of the conductive wire material, a tip of the conductive wire material at the peeled portion of the outer insulating layer is joined by welding or crimping to form a joint portion, and at least a portion other than the joint portion, in the conductive wire material at the peeled portion of the outer insulating layer, is varnished.

The conductive wire material of each phase includes the assembly of strands and the outer insulating layer made of an insulating material surrounding the assembly of strands. The strand has the conductor and the inner insulating layer of insulating material covering the conductor. The outer insulating layer is peeled off at the end of the conductive wire material for connecting the end of the conductive wire material to another electrical component.

A tip of the conductive wire material at the peeled portion of the outer insulating layer is joined by welding or crimping to form the joint portion. Therefore, it is possible to suitably suppress the occurrence of a situation in which the strands are untied at the end of the conductive wire material.

At least a portion other than the joint portion, in the conductive wire material at the peeled portion of the outer insulating layer, is the portion where the assembly of strands are exposed. At least this portion is varnished. As a result, in the peeled portion, the varnish may enter the recess part between the adjacent strands, or the varnish may enter the gaps inside the assembly of strands from between the strands. As a result, the varnish effectively clings and hardens to the portion of the assembly of strands that is exposed from the outer insulating layer. As a result, it is possible to more preferably suppress the occurrence of a situation in which the strands are untied at the end of the conductive wire material, thereby improving the workability in the manufacturing process of the armature winding.

A rotating electric machine according to the present disclosure is used, for example, as a vehicle power source. The rotating electric machine may, however, be used widely for industrial, automotive, aerial, domestic, office automation, or game applications.

As shown inFIGS.1and2, a rotating electric machine10is a synchronous multiphase alternating current (AC) motor and has an outer rotor structure (outer rotating structure). In the following description, in the rotating electric machine10, a direction in which a rotating shaft11extends is defined as an axial direction, a direction radially extending from a center of the rotating shaft11is defined as a radial direction, and a direction circumferentially extending around the rotating shaft11is defined as a circumferential direction.

The rotating electric machine10includes a rotating electric machine main body having a rotor20and a stator unit30, and a housing40provided so as to surround the rotating electric machine main body. Each of these members is disposed coaxially with the rotating shaft11integrally provided in the rotor20, and is assembled in an axial direction in a predetermined order to form the rotating electric machine10. The rotating shaft11is supported by a pair of bearings (not shown) provided in the stator unit30and the housing40, respectively, and is rotatable in this state. The rotation of the rotating shaft11causes, for example, the axle of a vehicle to rotate. The rotating electric machine10can be mounted on a vehicle by fixing the housing40to a vehicle body frame or the like.

In the rotating electric machine10, the stator unit30is provided so as to surround the rotating shaft11, and the rotor20is disposed on the outer side of the stator unit30in the radial direction. The stator unit30includes a stator50and a stator holder53assembled to the inner side of the stator50in the radial direction. The rotor20and the stator50are disposed to face each other in the radial direction with an air gap interposed therebetween. The rotor20rotates integrally with the rotating shaft11, so that the rotor20rotates on the outer side of the stator50in the radial direction. In the present embodiment, the rotor20corresponds to a “field element”, and the stator50corresponds to an “armature”.

FIG.6is a longitudinal cross-sectional view of the rotor20. As illustrated inFIG.2, the rotor20includes a substantially cylindrical rotor carrier21and an annular magnet unit22fixed to the rotor carrier21. The rotor carrier21includes a cylinder23having a cylindrical shape and an end plate portion24provided at one end of the cylinder23in the axial direction. The cylinder23and the end plate portion24are integrated to form the rotor carrier21. The rotor carrier21functions as a magnet retainer, and the magnet unit22is fixed to the inner side of the cylinder23in the radial direction to have an annular shape. The rotating shaft11is fixed to the end plate portion24. The cylinder23is made of, for example, a non-magnetic material, and specifically made of, for example, aluminum.

The magnet unit22has an annular shape concentric with a rotation center O of the rotor20and has a plurality of magnets31fixed to an inner peripheral surface of the cylinder23. That is, the rotating electric machine10is a surface magnet type synchronous machine (SPMSM). The magnet31is provided so as to be surrounded by the cylinder23from the outside in the radial direction. In the magnet unit22, the magnets31are provided side by side such that the polarities are alternately changed along the circumferential direction of the rotor20. Thereby, a plurality of magnetic poles are formed in the magnet unit22in the circumferential direction. The magnet31is a polar anisotropic permanent magnet, and is formed using a sintered neodymium magnet having an intrinsic coercive force of 400 [kA/m] or more and a remanent flux density Br of 1.0 [T] or more.

A peripheral surface of the magnet31on the inner side in the radial direction is a magnetic flux acting surface on which a magnetic flux is transmitted and received. The magnet31is oriented so that the direction of the easy magnetization axis on the d-axis side, which is the magnetic pole center, is closer to the direction of the d-axis than the direction of the easy magnetization axis on the q-axis side, which is the magnetic pole boundary. As a result, on the magnetic flux acting surface of the magnet31, magnetic flux is generated intensively in the region near the d-axis.

Next, a configuration of the stator unit30will be described.

The stator unit30includes the stator50and the stator holder53on the inner side of the stator50in the radial direction. The stator50has a stator winding51as an “armature winding” and a stator core52as an “armature core”. The stator holder53is made of, for example, metal such as aluminum or cast iron, or carbon fiber reinforced plastic (CFRP), and has a cylindrical shape.

The stator50includes, in the axial direction, a portion corresponding to a coil side facing the magnet unit22in the rotor20in the radial direction, and a portion corresponding to a coil end that is the outer side of the coil side in the axial direction. In this case, the stator core52is provided in a range corresponding to the coil side in the axial direction.

The stator winding51has a plurality of phase windings. The phase windings of respective phases are disposed in a predetermined order in the circumferential direction to be formed in a cylindrical shape. In the present embodiment, the stator winding51has a three-phase windings including the U-phase, the V-phase, and the W-phase windings51U,51V, and51W.

The U-, V-, and W-phase windings51U,51V, and51W are formed by winding a conductive wire material in multiple turns, as shown inFIG.3, for example. The U-, V-, and W-phase windings51U,51V, and51W includes a pair of intermediate conductor portions60and a pair of link portions61. The pair of link portions61are provided to be in parallel to each other and have a linear shape. The pair of link portions61respectively connect the pair of intermediate conductor portions60at both ends in the axial direction. The U-, V-, and W-phase windings51U,51V, and51W are formed to have an annular shape by the pair of intermediate conductor portions60and the pair of link portions61. In the U-, V-, and W-phase windings51U,51V, and51W, one end of the conductive wire material serves as a first end62and the other end serves as a second end63.FIG.1shows an arrangement order of the intermediate conductor portions60forming the U-, V-, and W-phase windings51U,51V, and51W in the coil side.

The stator core52is formed as a core sheet stacked body in which core sheets made of a magnetic steel sheet, which is a magnetic member, are stacked in the axial direction. The stator core52has a cylindrical shape having a predetermined thickness in the radial direction. The stator winding51is assembled to the outer side of the stator core52in the radial direction, that is, the rotor20side. The outer peripheral surface of the stator core52has a curved surface shape without protrusions and recesses. The stator core52functions as a back yoke. The stator core52is formed by stacking a plurality of core sheets in the axial direction. The core sheet is punched into, for example, an annular plate shape. However, the stator core52may have a helical core structure composed of strip-shaped core sheets.

In the present embodiment, the stator50has a slot-less structure having no tooth for forming a slot, but the configuration thereof may use any of the following (A) to (C).(A) The stator50includes a conductor-to-conductor member between each adjacent two of the intermediate conductor portions60in the circumferential direction. As the conductor-to-conductor member, a magnetic material having a relationship of Wt×Bs≤Wm×Br is used, where Wt represents a width dimension in the circumferential direction of the conductor-to-conductor member in one magnetic pole, Bs represents a saturation magnetic flux density of the conductor-to-conductor member, Wm represents a width dimension in the circumferential direction of the magnet31in one magnetic pole, and Br represents a remanent flux density of the magnet31.(B) The stator50includes a conductor-to-conductor member between each adjacent two of the intermediate conductor portions60in the circumferential direction. A non-magnetic material is used as the conductor-to-conductor member.(C) The stator50does not include a conductor-to-conductor member between each adjacent two of the intermediate conductor portions60in the circumferential direction.

Next, with reference toFIG.4, the manner of electrical connection between each of windings51U to51W and an inverter100will be described.

The rotating electric machine10includes the inverter100. The inverter100includes upper and lower arm switches SWH and SWL and a smoothing capacitor101corresponding to each phase. The inverter100is electrically connected to a storage battery110, which is a DC power supply.

The rotating electric machine10includes U-, V-, and W-phase bus bars70U,70V, and70W (corresponding to “components on the inverter side”) as main-bus bars and a neutral point bus bar71. Connection points of upper and lower arm switches SWH and SWL in inverter100are electrically connected to U-, V- and W-phase bus bars70U,70V and70W. Each of the bus bars70U,70V,70W, and71is fixed to the stator holder53, for example.

Next, with reference toFIG.5, the conductive wire material CR constituting each of the windings51U,51V, and51W will be described.

The conductive wire material CR is a magnet wire, and includes an assembly of strands83having a conductor81made of a copper material and an inner layer coating82(corresponding to an “inner insulating layer”) covering the conductor81, and an outer layer coating90(corresponding to an “outer insulating layer”) surrounding the assembly of strands83.FIG.5exemplifies the conductive wire material CR composed of nine strands83, but the number of strands83may be any number. Moreover, the cross-sectional shape of the conductive wire material CR is not limited to the rectangular shape shown inFIG.5, and may be, for example, a circular shape.

The inner layer coating82is made of an insulating material having thermoplasticity and electrical insulation, and epoxy resin, for example, is used as the insulating material. The inner layer coating82is not limited to a single layer, and may be composed of multiple layers. The strand83may be a self-bonding wire. In this case, the inner layer coating82is covered with a self-bonding layer. Also, the conductive wire material CR may be a twisted wire in which a plurality of strands83are twisted.

The outer layer coating90is made of an insulating material having thermoplasticity and electrical insulation, and the synthetic resin such as PPS resin, PEEK resin, PI resin, or PAI resin is used as the insulating material.

The thickness of the outer layer coating90is made thicker than the thickness of the inner layer coating82. This configuration is employed for correlation isolation. Further, the specific heat of the outer layer coating90is higher than the specific heat of the inner layer coating82, and the glass transition temperature of the outer layer coating90is higher than the glass transition temperature of the inner layer coating82.

Next, a manufacturing process of each phase winding51U,51V, and51W that constitutes the stator50will be described with reference toFIG.6. The U phase will be described below as an example.

In step S10, the outer layer coating90is peeled off from the first end62of the conductive wire material CR using a coating peeling device.FIG.7Ashows a longitudinal sectional view of the first end62before peeling, andFIG.7Bshows a longitudinal sectional view of the first end62after peeling.FIG.7shows a simplified assembly of strands83.

As the coating peeling device, for example, the device described below is used. The coating peeling device includes a gripping portion that grips the conductive wire material CR and peeling blades that peel off the outer layer coating90by coming into contact with the conductive wire material CR from both sides in the radial direction with respect to the first end62of the conductive wire material CR gripped by the gripping portion. The coating peeling device peels off the outer layer coating90at the first end62of the conductive wire material CR by sandwiching the conductive wire material CR with the peeling blades. Similarly, the outer layer coating90is peeled off by the coating peeling device with respect to the second end63as well.

In the following step S11, in the first end62of the conductive wire material CR, the tip of the peeled portion of the outer layer coating90and the first sub-bus bar64are welded using a welding device. In the present embodiment, the welding device is a laser welding device. A laser beam used in the welding device include, for example, gas laser such as CO2 laser, solid laser such as YAG laser, fiber laser such as Yb fiber laser, and semiconductor laser such as LD (Laser Diode) laser. The laser beam is irradiated from the welding device to the vicinity of the contact portion between the tip of the peeled portion of the outer layer coating90and the first sub-bus bar64at the first end62. As a result, the inner layer coating82of the irradiated portion by the laser beam is peeled off, and the vicinity of the contact portion between the tip of the peeled portion of the outer layer coating90and the first sub-bus bar64becomes the joint portion WL (FIG.7C). At this time, since the joint portion WL is formed after the inner layer coating82is peeled off to expose the conductor81, inclusion of the inner layer coating82in the joint portion WL is suppressed as much as possible. This suppresses an increase in the electrical resistance value of the joint portion WL.

In the welding process, as shown inFIG.7C, the tip of the outer layer coating90is heated by the heat of welding, so that the tip of the outer layer coating90is turned up radially outward of the conductive wire material CR. In the example shown inFIG.7C, the turned-up portion of the outer layer coating90spreads outward in the radial direction of the conductor portion60toward the tip of the first end62. The specific heat of the outer layer coating90having thermoplastic is higher than the specific heat of the inner layer coating82having thermoplastic, and the glass transition temperature of the outer layer coating90is higher than the glass transition temperature of the inner layer coating82. As a result, the inner layer coating82in the vicinity of the welded portion can be properly peeled off, and the turned-up portion can be properly formed without scorching the tip of the outer layer coating90. In addition, due to the extension of the conductive wire material CR, the length of the peeled portion of the outer layer coating90at the first end62is longer than the length of the joint portion WL. This also contributes to properly forming the turned-up portion without scorching the tip of the outer layer coating90.

In the first end62of the conductive wire material CR, the tip of the peeled portion of the outer layer coating90and the second sub-bus bar65are welded using a welding device. As a result, the tip of the outer layer coating90at the second end63is turned up radially outward of the conductive wire material CR.

In the following step S12, an inspection device inspects whether the first end62of the conductive wire material CR and the first sub-bus bar64, and the second end63of the conductive wire material CR and the second sub-bus bar65are electrically connected by welding.

In the following step S13, based on the inspection result by the inspection device, it is determined whether both of the electrical continuity between the first end62and the first sub-bus bar64and the electrical continuity between the second end63and the second sub-bus bar65are established. When the electrical continuity between at least one of the first end62and the first sub-bus bar64and between the second end63and the second sub-bus bar65is not confirmed, for example, the conductive wire material to which the first sub-bus bar64and the second sub-bus bar65is welded and connected.

On the other hand, when it is determined that the electrical continuity between the first end62and the first sub-bus bar64and the electrical continuity between the second end63and the second sub-bus bar65are confirmed, in step S14, the varnish treatment is applied to the first end62and the second end63side of the conductive wire material CR using a varnish treatment device.FIG.8Ashows a state in which the varnish CC is applied to the first end62. In the example shown inFIG.8A, in the conductive wire material CR, in addition to the portion other than the joint portion of the peeled portion of the outer layer coating90, the varnish CC is also applied to the joint portion WL and the portion of the outer layer coating90on the opposite side of the tip from the turned up portion. However, the varnish CC may be applied, for example, from the turned-up portion to the joint portion WL at the peeled portion of the outer layer coating90of the conductive wire material CR. Also, the varnish CC may be dried by, for example, a drying device.

In the following step S15, as shown inFIG.8B, the first sub-bus bar64is joined to the U-phase bus bar70U using an assembly device. Also, the second sub-bus bar65is joined to the neutral point bus bar71using the assembly device.

In the manufacturing process shown inFIG.6, the operations of the film peeling device, the welding device, the inspection device, the varnish treatment device, the drying device, the assembly device, etc. are controlled by a controller mainly composed of a computer. In step S13, the controller determines whether or not the electrical continuity has been confirmed based on the inspection results.

According to the present embodiment described in detail above, the following effects can be obtained.

The outer layer coating90is peeled from the first end62and the second end63of the conductive wire material CR. Only the tip of the peeled portion of the outer layer coating90of the conductive wire material CR is joined by welding to form the joint portion WL. Therefore, it is possible to suitably suppress the occurrence of a situation in which the strands83are untied at the first end62and the second end63.

Varnish CC is fixed to at least the exposed portion of the assembly of strands83and the joint portion WL of the peeled portion of the outer layer coating90in the conductive wire material CR. In the exposed portion, the varnish CC may enter the recess parts between the adjacent strands83and the varnish CC may enter the gaps inside the assembly of strands83from between the strands83. As a result, the varnish CC effectively clings and hardens to the portion of the assembly of strands83exposed from the outer layer coating90. As a result, it is possible to more preferably suppress the occurrence of a situation in which the strands83are untied at the first end62and the second end63, thereby improving the workability in the manufacturing process of the stator winding51.

When the tip of the peeled portion of the outer insulating layer90of the conductive wire material CR is welded in step S10, the tip of the outer insulating layer90having thermoplasticity is turned up radially outward of the conductive wire material due to the heat of the welding. The portion into which the varnish CC enters is formed between the outer layer coating90that has been turned up and the assembly of strands83. Therefore, the varnish treatment in step S14allows the varnish CC to more effectively cling to the conductive wire material CR.

In the welding process, the turned-up portion of the outer layer coating90can be formed together with the joint portion WL. Therefore, a structure for effectively clinging the varnish CC can be efficiently formed in the welding process.

The thickness of the outer layer coating90is made thicker than the thickness of the inner layer coating82. Further, the specific heat of the outer layer coating90is higher than the specific heat of the inner layer coating82, and the glass transition temperature of the outer layer coating90is higher than the glass transition temperature of the inner layer coating82. As a result, when welding the tip of the conductive wire material CR in the welding step, it is possible that the peeled portion of the outer insulation coating90is properly formed without burning the tip of the outer insulation coating90, and the joint portion is formed after removing the inner insulating coating82as much as possible by the heat of welding.

The windings of each phase confirmed to be electrically conductive in step S13are connected to the bus bars of each phase and the neutral point bus bar71. Therefore, it is possible to suitably suppress the occurrence of problems such as complication of the work process and the occurrence of parts discarding.

Other Embodiments

The above embodiment may be modified as follows.

The outer insulating layer is not limited to a coating, and may be formed of, for example, a tape spirally wound around an assembly of strands83. Enamel, for example, may be used as the inner layer coating82.

The welding in step S11ofFIG.6is not limited to the laser welding, and may be an arc welding such as TIG welding, or an electron beam welding.

Further, in step S11, instead of welding, the joint portion may be formed by pressure contact using a pressure contact device (for example, punch pressure contact).

In step S10, the outer layer coating90is peeled off by pinching the conductive wire material CR with peeling blades using the coating peeling device, and by pinching, as shown inFIG.9, a recess part91may be formed in the base end of the peeled portion of the outer layer coating90in the assemble of strands83. Since the varnish CC enters the recess part91, the varnish CC can more effectively cling to the conductive wire material CR. Therefore, the recess part91for effectively clinging the varnish CC can be formed efficiently, and workability in the manufacturing process of the stator winding51can be improved.

In step S10, when the inner layer coating82is peeled off by the laser welding in the welding process, as shown inFIG.10, a plurality of (three are exemplified) recess parts84may be formed in the conductor81exposed at the peeled portion of the inner layer coating82by the heat of the laser welding. The recess parts84are formed, for example, by melting the conductor81with the heat of laser welding. As a result, unevenness is formed on the surface of the conductor81, and the varnish CC enters the unevenness in the varnishing step of step S14, so that the varnish CC can more effectively cling to the conductive wire material CR. Therefore, the recess part84for effectively clinging the varnish CC can be formed efficiently in the welding process, and workability in the manufacturing process of the stator winding51can be improved.

In step S10, the outer layer coating90may be peeled off by irradiating the outer layer coating90with a laser beam from a laser welding device instead of the coating peeling device. In this case, in addition to the outer layer coating90, the inner layer coating82inside the outer layer coating90may be peeled off at the same time. For example, the outer layer coating90and the inner layer coating82can be properly peeled off at the same time by setting the thicknesses, specific heats, and glass transition temperatures of the inner layer coating82and the outer layer coating90.

The rotating electric machine is not limited to a star connection, and may be a Δ connection.

The rotating electric machine is not limited to the outer rotor type rotating electric machine, and may be an inner rotor type rotating electric machine. Further, the rotating electric machine is not limited to the one having the slotless structure, and may be one having teeth.

Of the field element and the armature, the rotating electric machine is not limited to the rotating electric machine in which the field element is the rotor, and may be the rotating electric machine in which the armature is the rotor.

The disclosure in the present specification is not limited to the illustrated embodiments. The disclosure encompasses the illustrated embodiments and modifications based on the embodiments by those skilled in the art. For example, the disclosure is not limited to the combinations of components and/or elements shown in the embodiments. The disclosure may be implemented in various combinations. The disclosure may have additional portions that may be added to the embodiments. The disclosure encompasses omission of components and/or elements of the embodiments. The disclosure encompasses the replacement or combination of components and/or elements between one embodiment and another. The disclosed technical scope is not limited to the description of the embodiments. The several technical ranges disclosed are indicated by the description of the claims, and should be construed to include all modifications within the meaning and range equivalent to the description of the claims.

The present disclosure has been described based on examples, but it is understood that the present disclosure is not limited to the examples or structures. The present disclosure encompasses various modifications and variations within the scope of equivalents. In addition, while the various combinations and configurations, which are preferred, other combinations and configurations, including more, less or only a single element, are also within the spirit and scope of the present disclosure.

As for a means 2 according to the means 1, the tip of the outer insulating layer is turned up radially outward of the conductive wire material.

In the means 2, a portion into which the varnish enters is formed between the turned-up outer insulating layer and the assembly of strands. As a result, the varnish can more effectively cling to the conductor.

In a means 3 according to the means 1 or 2, a conductive member which is a member joined to the joint portion and electrically connects the component on the inverter side and the conductor is provided.

According to the means 3, it is possible to improve the workability in the case of electrically connecting the conductors constituting the conductive wire material to the components on the inverter side.

In a means 4 according to any one of the means 1 to 3, a recess part is formed at the base end of the peeled portion of the outer insulating layer in the assembly of strands.

In the means 4, the varnish enters the recess part of the base end. As a result, the varnish can more effectively cling to the conductor.

In a means 5 according to any one of means 1 to 4, the inner insulating layer is peeled off at the tip of the peeled portion of the outer insulating layer in the assembly of strands, and the joint portion is formed at the tip of the peeled portion of the inner insulating layer.

A plurality of recess parts are formed in the conductor at the peeled portion of the inner insulating layer.

In the means 5, the varnish enters a plurality of recess parts formed in the conductor. As a result, the varnish can more effectively cling to the conductor.

Here, the armature winding of the means 1 can be manufactured like a means 6, for example. The means 6 includes a peeling step of peeling off the outer insulating layer at the end of the conductive wire material, a joining step of forming the joint portion by welding or crimping the tip of the conductive wire material at the peeled portion of the outer insulating layer, and a step of applying a varnish treatment to at least a portion other than the joint portion, in the conductive wire material at the peeled portion of the outer insulating layer.

In a means 7 according to the means 6, the outer insulating layer has thermoplasticity. The joining step is a step of forming the joint portion by welding the tip of the conductive wire material at the peeled portion of the outer insulating layer, and the tip of the outer insulating layer is heated by welding in the joining step, whereby the tip of the outer insulating layer is turned up radially outward of the conductive wire material.

In the means 7, a step of applying the varnish treatment is performed after the peeling step and the joining step. Here, when the tip of the peeled portion of the outer insulating layer of the conductive wire material is welded, the tip of the outer insulating layer having thermoplasticity is turned up radially outward of the conductive wire material due to the heat of the welding. In other words, in the joining step, it is possible to form the turned up portion of the outer insulating layer together with the joint portion. Therefore, a structure for effectively clinging the varnish can be efficiently formed, and workability in the manufacturing process of the armature winding can be improved.

In a means 8 according to the means 7, the inner insulating layer has thermoplasticity. A thickness of the outer insulating layer is thicker than a thickness of the inner insulating layer, and a specific heat of the outer insulation layer is greater than a specific heat of the inner insulation layer.

A potential difference between each strand in the assembly is relatively small. On the other hand, the potential difference between the conductive wire material in each of the different phases becomes very large, and it is necessary to require a correlative insulation of the conductive wire materials in each of the different phases. Therefore, in the means 8, the thickness of the outer insulating layer is made thicker than the thickness of the inner insulating layer. Here, in the means 8, the specific heat of the thermoplastic outer insulating layer is greater than the specific heat of the thermoplastic inner insulating layer. For this reason, when welding the tip of the conductive wire material in the joining step, it is possible that the peeled portion of the outer insulation layer is properly formed without burning the tip of the outer insulation layer, and the joint portion is formed after removing the inner insulating layer as much as possible by the heat of welding.

In a means 9 according to the means 7 or 8, the inner insulating layer has thermoplasticity. A thickness of the outer insulating layer is thicker than a thickness of the inner insulating layer, and a glass transition temperature of the outer insulating layer is higher than a glass transition temperature of the inner insulating layer.

In the means 9, the glass transition temperature of the outer insulating layer is higher than the glass transition temperature of the inner insulating layer. For this reason, when welding the tip of the conductive wire material in the joining step, it is possible that the peeled portion of the outer insulation layer is properly formed without burning the tip of the outer insulation layer, and the joint portion is formed after removing the inner insulating layer as much as possible by the heat of welding.

In a means 10 according to any one of the means 6 to 9, the joining step is a step of forming the joint portion by a welded portion between the tip and the conductive member by welding the tip of the peeled portion of the conductive wire material from which the outer insulating layer has been removed and the conductive member.

According to the means 10, it is possible to improve the workability when electrically connecting the conductors constituting the conductive wire material to other electric components.

A means 11 according to the means 10 includes an inspection step of inspecting whether or not the conductor and the conductive wire material are electrically connected after the joining step, and a step of electrically connecting the conductive wire material, which has been confirmed to be electrically conductive in the inspection step, to a component on the inverter side.

In the joining step, after electrically connecting the conductive member welded to the conductive wire material to the component on the inverter side, it may be inspected whether or not there is electrical continuity between the conductor constituting the conductive wire material and the conductive member. However, in this case, when the electrical continuity cannot be confirmed in the inspection, for example, it becomes necessary to remove the conductive member from the component on the inverter side, and a problem such as complicating the work process may arise. Further, for example, there may arise a problem that the inverter-side component electrically connected to the conductive member must be discarded together with the conductive member to which the conductive wire material is connected.

In this regard, in the means 11, the conductive member, which has been confirmed to be electrically conductive in the inspection step, is electrically connected to the component on the inverter side. Therefore, it is possible to suitably suppress the occurrence of the problem described above.

In a means 12 according to any one of the means 6 to 11, the peeling step peels off the outer insulating layer at the end of the conductive wire material by sandwiching the conductive wire material with a coating peeling device, and by sandwiching, forming the recess part at the base end of the peeled portion of the outer insulating layer in the assembly of strands.

In the means 12, in the peeling step, the outer insulating layer can be peeled off, and a recess part can be formed at the base end of the peeled portion of the outer insulating layer. As a result, in the process of applying the varnish treatment, the varnish can effectively cling by entering the recess part. As described above, according to the means 12, the structure for effectively clinging the varnish can be efficiently formed in the step of removing the outer insulating layer, and the workability in the manufacturing process of the armature winding can be improved.

In means 13 according to any one of means 6 to 12, the joining step peels off the inner insulating layer at the tip of the assemble of strands by welding the tip of the peeled portion of the outer insulating layer of the conductive wire material, thereby the tip of the peeled portion of the inner insulating layer is used as the joint portion, and when the inner insulating layer is peeled off by welding in the joining step, a plurality of recess parts are formed in the conductor exposed at the peeled portion of the inner insulating layer due to the heat of welding.

In the means 13, in the joining step, the inner insulating layer can be peeled off, and a plurality of recess parts can be formed in the conductor exposed at the peeled portion of the inner insulating layer. As a result, in the process of applying the varnish treatment, the varnish can effectively cling by entering the plurality of recess parts. As described above, according to the means 13, the structure for effectively clinging the varnish can be efficiently formed in the joining step, and the workability in the manufacturing process of the armature winding can be improved.