阅读说明：本技术 旋转电机、旋转电机的定子以及旋转电机的制造方法 (Rotating electrical machine, stator for rotating electrical machine, and method for manufacturing rotating electrical machine ) 是由 冈村知晋 于 2019-07-15 设计创作，主要内容包括：旋转电机(1)具有转子(4)和定子(10)。定子包括定子线圈(12)。定子线圈具有与线圈边端(14)包含的线圈端(16)电连接的导电构件制的母线(30)。定子具有对母线进行收容的绝缘构件制的保持件(21)。保持件定位成使开口部或树脂构件朝向定子铁芯相对。(A rotating electrical machine (1) has a rotor (4) and a stator (10). The stator includes a stator coil (12). The stator coil has a bus bar (30) made of a conductive member electrically connected to a coil end (16) included in the coil edge end (14). The stator has a holder (21) made of an insulating member for accommodating the bus bar. The holder is positioned so that the opening or the resin member is opposed toward the stator core.)

1. A stator of a rotary electric machine, comprising:

a stator core (11) providing a plurality of slots;

a stator coil (12) mounted to the stator core,

the stator coil has:

a coil side end (14) located at an end of the stator core;

a bus bar (30) made of a conductive member, electrically connected to a coil end (16) included in the coil edge end; and

and a holder (21) that is a container made of an insulating member and that houses the bus bar, is arranged in the axial direction of the stator core, and has an opening (22) facing the stator core.

2. The stator of a rotating electric machine according to claim 1,

the busbar comprises a main portion extending in a circumferential direction,

the retainer has a groove deeper than the height of the main portion,

the opening is also an opening of the groove,

the opening portion faces the stator core.

3. The stator of a rotating electric machine according to claim 1 or 2,

the holder is disposed axially outward of the coil edge or radially outward of the coil edge.

4. The stator of a rotating electric machine according to any one of claims 1 to 3,

and an insulating resin member (27) filling the opening.

5. The stator of a rotating electric machine according to claim 4,

the holder is made of a resin and is formed of a resin,

the resin member is made of a soft resin softer than a resin forming the holder.

6. The stator of a rotating electric machine according to claim 4 or 5,

the resin member includes an adhesive resin member that bonds the bus bar and the holder.

7. The stator of a rotating electric machine according to any one of claims 4 to 6,

the resin member embeds the bus bar in the opening of the holder.

8. The stator of a rotating electric machine according to any one of claims 4 to 7,

the bus bar has terminals (31, 32),

the terminal extends from a surface of the resin member.

9. The stator of a rotating electric machine according to any one of claims 4 to 8,

the resin member is potting resin.

10. The stator of a rotating electric machine according to claim 9,

the holder has a wall on the radially inner side and a wall on the radially outer side,

the potting resin has a lower surface than the top of the walls.

11. The stator of a rotating electric machine according to claim 9 or 10,

the holder has a radially innermost wall and a radially outermost wall,

the potting resin has a lower surface than the top of the walls.

12. The stator of a rotating electric machine according to any one of claims 4 to 11,

the resin member is a thermosetting resin.

13. The stator of a rotating electric machine according to any one of claims 1 to 12,

the holder is a resin molded article molded by injection molding.

14. A rotating electrical machine comprising:

a stator (10) of a rotating electric machine according to any one of claims 1 to 13;

a rotor (4) magnetically coupled with the stator; and

a housing (8) that houses the stator and the rotor and faces a wall surface of the holder.

15. A method of manufacturing a rotating electric machine,

a stator coil (12) is mounted to a stator core (11) provided with a plurality of slots with coil edge ends (14) at ends of the stator core,

a bus bar unit (20) is assembled by attaching a bus bar (30) made of a conductive member to an opening (22) of a holder (21) made of an insulating member,

positioning the bus bar unit such that the opening portion is opposed to an end portion in an axial direction of the stator core,

electrically connecting a coil end (16) included in the coil edge end with the bus bar,

the housing (8) is located radially and/or axially outside the wall of the holder.

16. The manufacturing method of a rotating electric machine according to claim 15,

further comprising a step of filling an insulating resin member (27) from the opening,

in the stage of positioning the bus bar unit, the resin member is positioned to be opposed to an end portion of the stator core.

17. The manufacturing method of a rotating electric machine according to claim 16,

the assembling stage of the bus bar unit comprises:

a stage of molding the holder by injection molding of an insulating resin; and

filling the resin member from the opening by potting and curing the resin member.

18. The manufacturing method of a rotating electric machine according to any one of claims 15 to 17,

in the phase of positioning the busbar unit,

positioning the bus bar unit such that the opening portion is opposed to the coil edge end.

Technical Field

The disclosure in this specification relates to a rotating electrical machine, a stator of the rotating electrical machine, and a method of manufacturing the rotating electrical machine.

Background

Patent documents 1 to 3 disclose stators of rotating electric machines. These stators have various coil ends. In particular, patent document 1 discloses a holder that accommodates a plurality of bus bars. The plurality of bus bars provide connection members at the side ends of the coil. The plurality of bus bars are fixed to the holder by an adhesive resin. The contents of the prior art documents cited as prior arts are cited as descriptions of technical elements in the present specification by reference.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2017-153261

Patent document 2: japanese patent laid-open No. 2000-166150

Patent document 3: japanese patent laid-open publication No. 2018-125924

Disclosure of Invention

In the conventional structure, air bubbles may be generated in the adhesive resin. Further, the bubbles sometimes form small holes. Air bubbles and pinholes sometimes impair the insulation performance.

In other points of view, the bonding resin may be more easily damaged than the holder.

In the above-described viewpoint or in other viewpoints not mentioned, further improvements are required for the rotary electric machine, the stator of the rotary electric machine, and the manufacturing method of the rotary electric machine.

An object of the present disclosure is to provide a rotating electric machine with improved insulation performance, a stator of the rotating electric machine, and a manufacturing method of the rotating electric machine.

Another object of the present disclosure is to provide a rotating electric machine, a stator of the rotating electric machine, and a manufacturing method of the rotating electric machine, in which insulation performance with respect to a plurality of bus bars is improved.

It is still another object of the present disclosure to provide a rotary electric machine, a stator of the rotary electric machine, and a manufacturing method of the rotary electric machine, in which insulation performance between a housing and a bus bar is improved.

The stator of a rotating electric machine disclosed herein includes a stator core (11) providing a plurality of slots and a stator coil (12) mounted to the stator core, wherein the stator coil has: a coil edge (14) positioned at an end of the stator core; a bus bar (30) made of a conductive member, the bus bar being electrically connected to a coil end (16) included in the coil edge end; and a holder (21) which is a container made of an insulating member for accommodating the bus bar, is arranged in the axial direction of the stator core, and has an opening (22) facing the stator core.

According to the disclosed stator of a rotating electrical machine, the holder is positioned so that the opening portion is opposed toward the stator core. As a result, the wall surface of the holder is positioned outside the stator core. Thereby, the insulation performance is improved.

The rotary electric machine disclosed herein includes: a stator (10) of the rotating electric machine; a rotor (4) magnetically coupled to the stator; and a housing (8) that houses the stator and the rotor and faces the wall surface of the holder.

In the disclosed method for manufacturing a rotating electric machine, a stator coil (12) is attached to a stator core (11) provided with a plurality of slots, coil end edges (14) are positioned at the ends of the stator core, a bus bar unit (20) is assembled by attaching a bus bar (30) made of a conductive member from an opening (22) of a holder (21) made of an insulating member, the bus bar unit is positioned so that the opening faces the end of the stator core in the axial direction, the coil ends (16) included in the coil end edges are electrically connected to the bus bar, and a housing (8) is positioned radially outside and/or axially outside the wall of the holder.

According to the manufacturing method of the rotary electric machine disclosed herein, the housing is positioned radially outward and/or axially outward of the wall of the holder. Thereby, the insulation performance is improved.

The various aspects disclosed in the present specification achieve the respective objects by adopting mutually different technical means. The claims and the parenthesized symbols described in the claims are exemplary of correspondence with the portions of the embodiment described later, and are not intended to limit the technical scope. The objects, features and effects disclosed in the present specification can be more clearly understood by referring to the following detailed description and accompanying drawings.

Drawings

Fig. 1 is a sectional view of a rotating electric machine according to a first embodiment.

Fig. 2 is a circuit diagram of the stator coil.

Fig. 3 is a perspective view of the stator.

Fig. 4 is a perspective view of the bus bar unit.

Fig. 5 is a perspective view of a plurality of bus bars.

Fig. 6 is a plan view of the bus bar unit.

Fig. 7 is a top view of a plurality of bus bars.

Fig. 8 is a top view of one bus bar.

Fig. 9 is a perspective view of the bus bar unit.

Fig. 10 is an end view taken along line X-X of fig. 6.

Fig. 11 is an end view taken along line XI-XI of fig. 6.

Fig. 12 is an end view taken along line XII-XII of fig. 6.

Fig. 13 is a perspective view of a neutral point bus bar.

Fig. 14 is a perspective view of a neutral point bus bar.

Fig. 15 is a circuit diagram of a stator coil according to the second embodiment.

Fig. 16 is a perspective view of the stator.

Fig. 17 is a perspective view of the bus bar unit.

Fig. 18 is a perspective view of a plurality of bus bars.

Fig. 19 is a plan view of the bus bar unit.

Fig. 20 is a top view of a plurality of bus bars.

FIG. 21 is a top view of one of the bus bars.

Fig. 22 is an end view of the bus bar unit of the third embodiment.

Fig. 23 is an end view of the bus bar unit of the fourth embodiment.

Fig. 24 is an end view of the bus bar unit of the fifth embodiment.

Fig. 25 is an end view of the bus bar unit of the sixth embodiment.

Fig. 26 is a circuit diagram of a stator coil according to the seventh embodiment.

Detailed Description

Hereinafter, a plurality of embodiments will be described with reference to the drawings. In the embodiments, the same reference signs are sometimes used for functionally and/or structurally corresponding parts and/or related parts, or reference signs differing by more than one hundred bits are sometimes used. For corresponding parts and/or associated parts, reference may be made to the description of the other embodiments.

First embodiment

In fig. 1, a rotating electrical machine 1 is a motor generator. The rotating electric machine 1 is operatively coupled to an internal combustion Engine (ENG) 2. The internal combustion engine 2 provides power for various devices. In this specification, the equipment includes a vehicle, an air conditioner, a water pump, and the like. Further, the term vehicle includes vehicles, boats, airplanes, simulation devices, and entertainment devices.

The rotating electric machine 1 is electrically connected to a control device (CNT) 3. The control device 3 includes an inverter circuit. When functioning as a generator, the rotating electrical machine 1 is driven by the internal combustion engine 2 to output electric power. When the rotating electrical machine 1 functions as a generator, the control device 3 functions as a rectifier circuit that rectifies electric power output from the rotating electrical machine 1. When the rotating electric machine 1 functions as an electric motor, the rotation of the internal combustion engine 2 is assisted. When the rotating electrical machine 1 is used as a motor, the control device 3 supplies the rotating electrical machine 1 with the multiphase ac power. In the present embodiment, the multiphase ac power is three-phase power.

The Control device 3 is an Electronic Control Unit (Electronic Control Unit). The control device 3 provides a control system. The control system has at least one arithmetic processing unit (CPU) and at least one memory device as a recording medium for recording programs and data. The control system is provided by a microcomputer including a recording medium readable by the computer. The recording medium is a non-transitory tangible recording medium that stores a program readable by a computer non-temporarily. The recording medium can be provided by a semiconductor memory, a magnetic disk, or the like. The control system can be provided by a computer or a set of computer resources linked by data communication means. The means and/or functions provided by the control system can be provided by software recorded in the physical memory device and a computer executing the software, software only, hardware only, or a combination thereof. For example, the control system can be provided by logic of the form referred to as "if-then-else" (if-then-else) or a neural network tuned by machine learning. Alternatively, for example, in the case where the control system is provided by an electronic circuit as hardware, it can be provided by a digital circuit or an analog circuit including a plurality of logic circuits.

The rotating electric machine 1 has a rotor 4 and a stator 10. The rotor 4 is rotatable about an axis AX. The stator 10 has a cylindrical shape with an axis AX. In the following description, the terms axial, radial, and circumferential are defined by the axis AX. The rotor 4 and the stator 10 are housed in the housing 6. The housing 6 fixes the stator 10 and rotatably supports the rotor 4. The housing 6 sometimes provides a component of the internal combustion engine 2. For example, the housing 6 sometimes provides a portion of a crankcase or a portion of a gearbox. The case 6 has a first case 7 having a bottomed cylindrical shape and a second case 8 having a bottomed cylindrical shape. The rotor 4 and the stator 10 are accommodated between the first casing 7 and the second casing 8.

The rotor 4 is magnetically coupled to the stator 10. The rotor 4 is supported by a shaft 5 so as to be rotatable relative to a housing 6. The shaft 5 provides a rotation axis. The rotary shaft is coupled to the internal combustion engine 2. The rotor 4 is disposed radially inward of the stator 10. The rotor 4 has a plurality of magnetic poles arranged in the circumferential direction. The plurality of magnetic poles are formed by a plurality of permanent magnets buried in the rotor 4. The rotor 4 can be provided by various structures. The rotor 4 has, for example, eight (N pole: four, S pole: four) magnetic poles.

The rotating electric machine 1 has a power terminal 9. The rotating electric machine 1 has a plurality of power terminals 9. The power terminal 9 is a terminal for electrically connecting the rotating electric machine 1 and the control device 3. The power terminal 9 serves as an output terminal when outputting power and serves as an input terminal when receiving power. The power terminal 9 can also be referred to as an external connection terminal of the rotating electrical machine 1.

The stator 10 has a stator core 11. The stator core 11 has a cylindrical shape. The stator core 11 is also annular. Stator core 11 has a plurality of steel plates stacked in the axial direction. The stator core 11 has a plurality of slots arranged in the circumferential direction. The plurality of slits are arranged at equal intervals in the circumferential direction. The plurality of cuts may be arranged at several different pitches. The plurality of slits extend in the axial direction so as to penetrate the plurality of steel plates. Furthermore, the plurality of cutting grooves are expanded in the radial direction. The typical stator core 11 has a ring-shaped supporting core. The stator core 11 has a plurality of pole teeth extending radially inward from the support core. The plurality of teeth have a plurality of slots formed therebetween. For example, the stator core 11 has forty-eight slots.

The stator 10 has a stator coil 12. The stator coil 12 is mounted on the stator core 11. The stator coil 12 has a straight portion 13 and coil side ends 14, 15. The straight portion 13 extends straight. The linear portion 13 is accommodated in the notch. The coil side ends 14, 15 are positioned at the ends of the stator core 11. The coil side ends 14, 15 protrude from the stator core 11. The coil edge ends 14 and 15 are an aggregate of a plurality of conductors included in the stator coil 12. In the coil side ends 14, 15, one conductor connects the straight portion 13 located in one slot with the straight portions 13 located in the other different slots. The coil ends 14, 15 are sometimes provided by turns of a continuous conductor. The coil ends 14, 15 are sometimes provided by joints joining different conductors. These examples are disclosed in patent document 2 or patent document 3.

The stator coil 12 has a coil end 16. The coil end 16 is a lead-out wire extending from the coil edge end 14. The stator coil 12 includes a plurality of coil ends 16. The coil ends 16 constitute both ends of the plurality of coils as a multi-phase winding. In the present embodiment, a three-phase winding is provided, and thus at least six coil ends 16 are provided. In the present embodiment, one phase is provided by parallel connection of n coils. Thus, the stator coil 12 has a 6 × n coil end 16. In the present embodiment, one phase is provided by parallel connection of four coils. Thus, the stator coil 12 includes twenty-four coil ends 16.

A coil can be provided by a continuous wire or by the joining of a plurality of sections. In this embodiment, one coil is provided by a plurality of sections joined. In addition, the plurality of sections can be joined by a plurality of joining methods. The joining method can be, for example, TIG welding, resistance welding, solder joining, or the like. In addition, one coil is a coil that can be regarded as one phase. One coil may also include therein a plurality of coil elements that differ in electrical angle. For example, one coil can comprise a plurality of coil elements that differ in electrical angle by a few degrees.

The stator coil 12 has a bus bar unit 20. The bus bar unit 20 electrically connects the stator coils 12 in such a manner as to form a multiphase wiring. The bus bar unit 20 connects the plurality of coil ends 16 in such a manner as to form a star connection or a delta connection. In the present embodiment, the bus bar unit 20 provides star connection. The bus bar unit 20 includes a plurality of bus bars 30. The plurality of bus bars 30 are made of a conductive member. The bus bar unit 20 has an end bus bar that provides three input and output terminals (power terminals) in the star connection. The busbar unit 20 has a neutral point busbar providing a neutral point in the star connection.

The bus bar unit 20 has a holder 21. The holder 21 is made of an insulating material. The holder 21 has an arc shape. The holder 21 may also be a polyhedron. The holder 21 may be annular. The holder 21 is disposed along the coil edge 14. The holder 21 is disposed axially outward of the coil edge 14. In addition, at least a part of the holder 21 is disposed radially outward of the coil edge 14. The holder 21 is opposed to a radially outer corner of the coil edge 14. The holder 21 is a container that accommodates the bus bar 30 therein.

In fig. 1, a plurality of bus bars 30 are illustrated as one bus bar 30. In fig. 1, the interior of the holder 21 is schematically illustrated. The plurality of bus bars 30 provide a plurality of discrete terminals 31. The discrete terminals 31 are also referred to as coil connection terminals. The discrete terminals 31 extend from the holder 21. The dispersion terminals 31 have a shape called J-shape or U-shape. The discrete terminals 31 extend in the axial direction from the holder 21 toward the coil edge 14, then expand outward in the radial direction, and further extend in the axial direction outward in the radial direction of the holder 21. The plurality of discrete terminals 31 are electrically connected to the plurality of coil terminals 16. The plurality of discrete terminals 31 are electrically connected to the plurality of coil ends 16 on the radially outer side of the holder 21. The coil end 16 and the discrete terminals 31 are electrically connected at the joint 17. The joint 17 can be provided by a variety of joining methods. The joining method can be, for example, TIG welding, resistance welding, solder joining, or the like.

The plurality of bus bars 30 provide a plurality of collective terminals 32. The set terminal 32 is also referred to as a power connection terminal. The plurality of set terminals 32 are electrically connected to the plurality of power terminals 9. The collective terminals 32 extend from the holder 21. The collective terminal 32 has a shape called J-shape or U-shape. The collective terminal 32 extends in the axial direction from the holder 21 toward the coil side end 14, then expands outward in the radial direction, and further extends in the axial direction outward in the radial direction of the holder 21. The plurality of set terminals 32 are electrically connected to the plurality of power terminals 9 on the radially outer side of the holder 21. The collective terminal 32 and the power terminal 9 are electrically connected at the joint 18. The engaging portion 18 can be provided by a variety of engaging methods. The joining method can be, for example, TIG welding, resistance welding, solder joining, or the like.

Fig. 2 shows a polyphase connection of the stator coil 12. The stator coil 12 employs a star connection as a multiphase connection. The stator coil 12 has a U-phase, a V-phase, and a W-phase. The stator coil 12 has a plurality of U-phase coils 12U that provide U-phase. The stator coil 12 has a plurality of V-phase coils 12V providing a V-phase. The stator coil 12 has a plurality of W-phase coils 12W that provide a W phase. In the present embodiment, the stator coil 12 includes four U-phase coils 12U, four V-phase coils 12V, and four W-phase coils 12W.

The plurality of buses 30 have a U-phase bus 30U that provides a U-phase power terminal. The U-phase bus bar 30U has four dispersion terminals 31. The U-phase bus bar 30U is connected to the four U-phase coils 12U at four junctions 17U, respectively. The U-phase bus bar 30U is connected to the power terminal 9 at the joint 18U. Therefore, the U-phase bus bar 30U provides a so-called crossover connecting the four U-phase coils 12U to the power terminals.

The plurality of buses 30 have a V-phase bus 30V that provides a V-phase power terminal. The V-phase bus bar 30V has four dispersion terminals 31. The V-phase bus bar 30V is connected to the four V-phase coils 12V at four joints 17V, respectively. The V-phase bus bar 30V is connected to the power terminal 9 at a joint 18V. Thus, the V-phase bus 30V provides a so-called crossover connecting the four V-phase coils 12V to the power terminals.

The plurality of bus bars 30 have a W-phase bus bar 30W that provides a W-phase power terminal. The W-phase bus bar 30W has four dispersion terminals 31. The W-phase bus bar 30W is connected to the four W-phase coils 12W at four junctions 17W, respectively. The W-phase bus bar 30W is connected to the power terminal 9 at the joint 18W. Therefore, the W-phase bus bar 30W provides a so-called crossover connecting the four W-phase coils 12W to the power terminals.

The plurality of bus bars 30 have a plurality of neutral point bus bars 41. Two neutral bus bars 41a, 41b provide two star connections. One neutral point bus bar 41a has six terminals. Twelve terminals are provided by two neutral point bus bars 41a, 41 b. The neutral point bus bar 41a is joined to the coil end for the neutral point at two joining portions 19u, 19v, 19 w. The neutral point bus bar 41b is joined to the coil end for the neutral point at two joining portions 19u, 19v, 19 w.

Fig. 3 shows an appearance of one end of the stator 10. Stator core 11 has one end face 11a and the other end face 11 b. The coil edge 14 extends in the axial direction from one end surface 11 a. The coil edge end 15 extends from the other end surface 11b in the axial direction. A busbar unit 20 is positioned axially of the coil end 14. The bus bar unit 20 is positioned in a predetermined angular range including the angular range in which the power terminal 9 is positioned. The holder 21 is positioned away from the coil edge 14 in the axial direction.

In the figure, twelve engaging portions 17 are illustrated. One joint 17 electrically connects one coil end 16 and one discrete terminal 31. The coil end 16 is L-shaped. The coil end 16 is led out from the radially outer side surface of the coil edge end 14. The coil end 16 extends axially outward from the coil edge end 14. The dispersion terminal 31 extends radially outward from the holder 21 and then axially outward at a radially outer end. Both the coil end 16 and the dispersion terminal 31 form the joint 17 at the end portion extending in the axial direction.

The stator 10 has six set terminals 32. A set of the collective terminals 32 (two collective terminals 32) adjacent in a short distance in the circumferential direction substantially provides one collective terminal 32 in one bus bar. The power terminals of the U-phase, V-phase, and W-phase are provided by three sets of set terminals 32. In other words, the bus bar unit 20 has three sets of six collecting terminals 32.

The busbar unit 20 has a neutral point busbar 41. The neutral point bus bar includes a plurality of neutral point bus bars 41a (41 b). The neutral point bus bar 41a (41b) is independent of the holder 21. The neutral point bus bar 41a (41b) is arranged radially outward of the coil edge 14 along the coil edge 14. The neutral point bus bar 41a and the neutral point bus bar 41b are arranged radially outside the coil edge 14 so as not to overlap each other.

Fig. 4 shows a bus bar unit 20. The illustrated bus bar unit 20 includes a holder 21 and a plurality of bus bars 30 housed in the holder 21. The illustrated busbar unit 20 does not include the neutral point busbar 41a (41 b). The illustrated bus bar unit 20 provides so-called crossover wires connecting the plurality of coils to the power terminals.

Fig. 5 shows a plurality of bus bars 30. The plurality of bus bars 30 has three bus bars 35, 36, 37. The three bus bars 35, 36, 37 provide a U-phase bus bar 30U, a V-phase bus bar 30V, and a W-phase bus bar 30W, respectively. The three bus bars 35, 36, 37 are electrically insulated from each other. The three bus bars 35, 36, 37 are arranged in a plurality of layers in the radial direction. The bus bar 35 is disposed at the radially innermost position. The bus bar 35 is also referred to as an inner layer bus bar 35. The bus bar 37 is disposed at the radially outermost position. The bus bar 37 is also referred to as an outer bus bar 37. The bus bar 36 is disposed between the inner layer bus bar 35 and the outer layer bus bar 37. The bus bar 36 is also referred to as an intermediate layer bus bar 36.

The plurality of bus bars 30 each have a main portion 38 extending in the circumferential direction. The main portion 38 is arcuate. The main portion 38 may be a polyhedron. The main portion 38 has a height H38 in the axial direction. The main portion 38 extends in a circumferential band shape.

The busbar 35 has two partial busbars 35a, 35b independent in the circumferential direction. The partial bus bar 35a has an arc shape of 90 degrees or less. The partial bus bar 35a has two discrete terminals 31. The partial bus bar 35a has one collective terminal 32. The partial bus bar 35b has an arc shape of 90 degrees or less. The partial bus bar 35b has two discrete terminals 31. The partial bus bar 35b has one collective terminal 32. Both the partial bus bar 35a and the partial bus bar 35b are disposed in the inner layer. Both the partial generatrix 35a and the partial generatrix 35b provide a generatrix 35 occupying an angular range of more than 90 degrees.

The busbar 36 has two partial busbars 36a, 36b independent in the circumferential direction. The partial bus bar 36a has an arc shape of 120 degrees or less. The partial bus bar 36a has two discrete terminals 31. The partial bus bar 36a has one collective terminal 32. The partial bus bar 36b has an arc shape of 120 degrees or less. The partial bus bar 36a has two discrete terminals 31. The partial bus bar 36b has one collective terminal 32. Both the partial bus bar 36a and the partial bus bar 36b are disposed in the intermediate layer. The partial bus bar 36a and the partial bus bar 36b are continuously arranged in the circumferential direction, thereby providing the bus bar 36 occupying an angular range of 120 degrees or more.

The bus bar 37 has two partial bus bars 37a, 37b independent in the circumferential direction. The partial bus bar 37a has an arc shape of 90 degrees or less. The partial bus bar 37a has two discrete terminals 31. The partial bus bar 37a has one collective terminal 32. The partial bus bar 37b has an arc shape of 90 degrees or less. The partial bus bar 37b has two discrete terminals 31. The partial bus bar 37b has one collective terminal 32. Both the partial bus bar 37a and the partial bus bar 37b are disposed on the outer layer. Both the partial busbar 37a and the partial busbar 37b provide a busbar 37 that occupies an angular range of 90 degrees or more.

In the present embodiment, one bus bar is provided by a plurality of partial bus bars. This enables the size of the partial bus bar to be reduced. The plurality of partial bus bars facilitates the manufacturing method. In addition, one bus bar has a plurality of set terminals 32. As a result, concentration of current is avoided.

Fig. 6 shows the bus bar unit 20. Fig. 6 shows a plane viewed from arrow VI of fig. 3. All the terminals 31, 32 extend radially outward of the holder 21.

Fig. 7 shows a plurality of bus bars 30. The plurality of set terminals 32 are arranged collectively. The collective arrangement of the plurality of collective terminals 32 makes it possible to efficiently connect with the plurality of power terminals 9. On the other hand, the plurality of discrete terminals 31 are arranged along the coil edge 14 in a dispersed manner. The dispersed arrangement of the plurality of dispersed terminals 31 suppresses confusion of the coil end 16 at the coil side end 14. The intervals of the plurality of discrete terminals 31 correspond to the pitch of the plurality of notches or a multiple of the pitch.

Fig. 8 shows one bus bar 37. One bus bar is bisected with respect to the position where the set terminals 32 and 32 are to be provided. The two partial busbars 37a, 37b are of symmetrical shape.

Fig. 9 shows the back surface of the bus bar unit 20. The holder 21 has an opening 22. The holder 21 may also be referred to as an arc-shaped container around the axis AX. The opening 22 opens in the axial direction. The opening 22 is widely opened so as to be able to receive the plurality of bus bars 30 in the axial direction. The plurality of bus bars 35, 36, 37 partially overlap each other in the radial direction. The plurality of bus bars 35, 36, and 37 are arranged to be offset from each other in the circumferential direction. Therefore, the angular range over which the retainer 21 expands in the circumferential direction is larger than the angular range of any of the plurality of bus bars 35, 36, 37. The holder 21 has a non-arrangement angle range in which the bus bar is not accommodated at both ends of the arc. The non-arrangement angle range is formed inside at one end of the circular arc. The non-disposition angle range is formed on the outer side at the other end of the circular arc. The plurality of terminals 31, 32 extend radially outward from the inner layer, the intermediate layer, and the outer layer, respectively. The plurality of terminals 31 and 32 are arranged radially with respect to the axis AX.

Returning to fig. 3, the holder 21 is a container made of an insulating member that houses the bus bar 30. The holder 21 is disposed in the axial direction of the stator core 11. Opening 22 opens toward stator core 11. Opening 22 faces stator core 11. The bus bar unit 20 is positioned such that the opening 22 faces one end face 11a of the stator core 11. The busbar unit 20 is positioned axially outward of the coil side end 14. As a result, the bus bar unit 20 is positioned such that the opening 22 is opposed to the coil side end 14. The bus bar unit 20 is positioned axially outside the coil edge 14 in such a manner that the holder 21 is laid down.

Fig. 10 shows an end face of the cut portion of the X-X line of fig. 6. The holder 21 has a plurality of partitions 26 therein for defining an inner layer, an intermediate layer, and an outer layer. The holder 21 has an opening 22. The holder 21 has a bottom wall 23, a radially outer wall 24 and a radially inner wall 25. The outer wall 24 provides a radially outer surface 24 a. The inner wall 25 provides a radially inner surface 25 a. The holder 21 has one or more partition walls 26. The partition walls 26 divide the inside of the retainer 21 into a plurality of layers (grooves) in the radial direction. The illustrated embodiment has two partitions 26a, 26 b. The outer wall 24 and the inner wall 25 have heights H24, H25. Height H24 is equal to height H25 (H24 ═ H25). The partitions 26a, 26b have a height H26. Height H26 is lower than height H24 or height H25 (H26 < H24, H26 < H25). The thickness of the partition walls 26a, 26b in the radial direction is thicker than the thickness of the outer wall 24 and the inner wall 25 in the radial direction. This difference in thickness allows the electrical insulation properties to be satisfied. The partition wall 26 is a circumferentially continuous wall. However, the partition wall 26 may be provided by a plurality of walls intermittently arranged in the circumferential direction. The partition 26 may have one or more openings penetrating in the radial direction. The partition walls 26 are also referred to as ribs.

The outer wall 24, the inner wall 25 and the plurality of partition walls 26a, 26b form a plurality of slit-shaped bus bar compartments. The illustrated embodiment forms three bus bar compartments. Bus bars 35, 36, and 37 are inserted into the bus bar chambers, respectively. The plurality of partition walls 26a, 26b provide a long creepage distance between the plurality of bus bars 35, 36, 37 arranged in multiple layers in the radial direction. Therefore, the plurality of partition walls 26a, 26b can suppress creeping discharge.

The bus bars 35, 36, 37 may also be pressed into the bus bar compartment. Further, a gap may be positively formed between the holder 21 and the bus bars 35, 36, and 37. In addition, the contact portions and the gaps may be alternately formed between the holder 21 and the bus bars 35, 36, 37. The clearance allows the presence of a resin member described later.

The holder 21 has an insulating resin member 27 filled in the opening 22. The resin member 27 is filled from the opening 22. The resin member 27 is filled into the inside of the holder 21. The resin member 27 bonds the inner surface of the holder 21 to the surfaces of the bus bars 35, 36, 37. The resin member 27 is filled in the holder 21. The resin member 27 covers the main portion 38 of the bus bars 35, 36, 37.

The resin member 27 is potting resin. The resin member 27 is dropped from the opening 22 and cured in the holder 21. The surface 27a of the resin member 27 contacts the side surfaces of the plurality of walls 24, 25, 26 at the boundary line 27 b. The surface 27a is concavely curved. The height of the resin member 27 is lower than the height of the plurality of walls 24, 25, 26. The resin member 27 has a surface 27a lower than the top of the plurality of walls 24, 25, 26.

When focusing on the bus bar 35, the holder 21 has a partition wall 26b located radially inside and an inner wall 25 located radially outside. The bus bar 35 is housed in a groove surrounded by the bottom wall 23, the partition wall 26b, and the inner wall 25. The resin member 27 covers the bus bar 35.

When focusing on the bus bar 36, the holder 21 has a partition 26a located radially inside and a partition 26b located radially outside. The bus bar 36 is housed in a groove surrounded by the bottom wall 23, the partition wall 26a, and the partition wall 26 b. The resin member 27 covers the bus bar 36.

When focusing on the bus bar 37, the holder 21 has the partition wall 26a positioned radially inside and the outer wall 24 positioned radially outside. The bus bar 37 is housed in a groove surrounded by the bottom wall 23, the outer wall 24, and the partition wall 26 a. The resin member 27 covers the bus bar 37.

Also, the holder 21 has an inner wall 25 located at the radially innermost side and an outer wall 24 located at the radially outermost side. The resin member 27 has a surface 27a lower than the tops of the inner wall 25 and the outer wall 24. As a result, the resin members 27 are separately arranged in the plurality of grooves provided in the holder 21, respectively.

The holder 21 is made of resin. The holder is a resin molded article molded by injection molding. The resin member 27 is made of a soft resin softer than the resin forming the holder 21. The resin member 27 is also an adhesive resin member that bonds the bus bar 30 to the holder 21. The resin member 27 embeds the bus bar 30 in the opening 22 of the holder 21. The resin member 27 is a thermosetting resin.

Returning to fig. 3, the resin member 27 faces one end face 11a of the stator core 11. The resin member 27 is opposed to the coil edge 14.

Fig. 11 shows an end face of the cut portion of the line XI-XI of fig. 6. A cut surface of one discrete terminal 31 is shown. The discrete terminals 31 have first portions 31 a. The first portion 31a extends axially from the main portion 38. The first portion 31a protrudes from the opening portion 22. The discrete terminals 31 have second portions 31 b. The second portion 31b extends from an end of the first portion 31a radially outward. The second portion 31b protrudes further radially outward than the holder 21. The discrete terminals 31 have third portions 31 c. The third portion 31c extends from the front end of the second portion 31b in the axial direction so as to overlap with the radially outer side of the holder 21. The third portion 31c reaches a position overlapping the holder 21 in the radial direction. The third portion 31c is opposed to the outer surface 24a of the holder 21. In the position of fig. 11, the outer bus bar 37 is not present. The plurality of bus bars 35, 36, 37 partially overlap each other in the radial direction. The plurality of bus bars 35, 36, and 37 are arranged to be offset from each other in the circumferential direction.

Fig. 12 shows an end face of the cut portion on the line XII-XII in fig. 6. A cut surface of one set terminal 32 is shown. The set terminal 32 has a first portion 32 a. The first portion 32a extends axially from the main portion 38. The first portion 32a protrudes from the opening portion 22. The set terminal 32 has a second portion 32 b. The second portion 32b extends radially outward from the end of the first portion 32 a. The second portion 32b protrudes further radially outward than the holder 21. The set terminal 32 has a third portion 32 c. The third portion 32c extends from the front end of the second portion 32b in the axial direction so as to overlap with the radially outer side of the holder 21. The third portion 32c reaches a position overlapping the holder 21 in the radial direction. The third portion 32c is opposed to the outer surface 24a of the retainer 21.

Fig. 11 and 12 show a plurality of terminals 31 and 32 included in one bus bar 36. The plurality of terminals 31 and 32 extend from the opening 22 of the holder 21. These terminals 31, 32 extend from the surface of the resin member 27. The busbar 30 includes a main portion 38 extending in the circumferential direction. The retainer 21 has a groove deeper than the height H38 of the main portion 38. The opening 22 is also an opening of the groove.

Fig. 13 shows one of the neutral point bus bars 41. Fig. 14 shows a busbar 44 of the neutral point busbar 41. The neutral bus bar 41 is intended to be mounted to the side of the coil side end 14. The neutral point bus bar 41 has an arc shape. The neutral point bus bar 41 has a main body 42 covered with an insulating member. The main body portion 42 extends in the circumferential direction. The main body 42 accommodates a bus bar 44 made of a conductive material. The neutral point bus bar 41 has a plurality of terminals 43 extending in the axial direction. In the illustrated example, the neutral point bus bar 41 has six terminals 43. The terminal 43 engages the coil end 16 for neutral connection. In the present embodiment, since two neutral point bus bars 41 are used, twelve terminals are provided in total.

A method of manufacturing the rotating electric machine 1 will be described. The method of manufacturing the rotating electric machine 1 includes a stage of assembling the rotor 4, a stage of assembling the stator 10, and a stage of housing the rotor 4 and the stator 10 in the housing 6. The rotor assembly stage and the stator assembly stage may also be in reverse order. The assembly phase of the stator 10 comprises: the stator core 11 provided with a plurality of slots is manufactured, the stator coil 12 is mounted on the stator core 11, and the coil end 14 is positioned at the end of the stator core 11. The step of positioning the coil end 14 includes a step of placing the plurality of coil ends 16 at predetermined positions by pulling the plurality of coil ends 16 out of the coil end 14.

The assembly phase of the stator 10 comprises a phase of assembling the busbar unit 20. The bus bar unit assembling stage includes a stage of molding the holder 21 by injection molding of an insulating resin. In this stage, the holder 21 having the opening portion 22 is molded. A plurality of partition walls 26a, 26b are formed inside the holder 21 to form a plurality of grooves. The bus bar unit assembling step includes a step of attaching the bus bar 30 made of a conductive member to the opening 22 of the holder 21 made of an insulating member.

The bus bar unit assembling step includes a step of filling the insulating resin member 27 from the opening 22. This step is a step of dropping the resin member 27 from the opening 22 by potting and curing it. In this stage, the holder 21 is positioned so that the opening 22 faces upward in the gravity direction. The resin member 27 is dropped toward the opening 22 from above. The resin member 27 forms a concave surface 27a by shrinkage or surface tension accompanying curing. The resin member 27 is filled to embed the plurality of bus bars 30.

The busbar unit assembly phase can also be performed independently. The busbar unit assembly phase may also be performed before the other phases. The bus bar unit assembling stage may include a stage of applying an adhesive to the inside of the holder 21 and a stage of mounting the bus bar 30 thereafter. The bus bar unit assembly stage may also fill the resin member 27 after.

The assembly stage of the stator 10 includes a stage of positioning the bus bar unit 20 so that the opening 22 faces one end surface 11a of the stator core 11 in the axial direction. At this time, the bus bar unit 20 is inverted from the posture at the stage of filling the resin member 27. In a typical stator manufacturing method, the stator 10 is positioned with the coil side ends 14 facing upward, and the bus bar unit 20 is placed above the coil side ends 14. At this time, the bus bar unit 20 is positioned with the opening 22 facing downward. This stage is also a stage of positioning the resin member 27 so as to oppose one end face 11a of the stator core 11. In other aspects, the bus bar unit 20 is positioned so that the opening 22 faces the coil edge 14. In other words, this stage is also a stage of positioning the bus bar unit 20 so that the resin member 27 faces the coil edge 14. As a result, the bottom wall 23 of the holder 21 is positioned axially outward of the stator 10.

The assembly stage of the stator 10 includes a stage of electrically connecting the plurality of coil ends 16 included in the coil edge end 14 and the plurality of terminals 31, 32. The plurality of terminals 31, 32 and the plurality of coil ends 16 are positioned radially outward of the holder 21. Further, one terminal 31, 32 to be electrically engaged and one coil end 16 are positioned at the same angular position in the circumferential direction. Therefore, a plurality of joining operations can be easily performed. At this time, the bus bar unit 20 is positioned away from the coil side end 14, and in this state, the plurality of coil ends 16 are engaged with the plurality of terminals 31, 32. As a result, the bus bar unit 20 is supported by the plurality of coil ends 16 and the plurality of terminals 31 and 32. Further, this stage includes a stage of joining the coil end 16 for neutral point and the neutral point bus bars 41a, 41 b.

The stage of housing the rotor 4 and the stator 10 in the housing 6 includes a stage of positioning the housing 8 radially outward and/or axially outward of the bottom wall 23 of the holder 21.

According to the embodiments described above, a rotating electrical machine with improved insulation performance, a stator thereof, and a method of manufacturing a rotating electrical machine can be provided. By opposing the opening 22 to the one end surface 11a, exposure of the bus bar 30 housed in the holder 21 can be suppressed. Therefore, a decrease in insulation performance in the assembly stage or the maintenance stage is suppressed.

Further, by opposing the resin member 27 to the one end face 11a, the holder 21 is positioned outside. Thereby, in the assembly stage or the maintenance stage, the resin member 27 is protected. Since the retainer 21 having less defects of the insulating member faces outward, the insulation is improved. On the other hand, since the resin member 27, which is relatively likely to cause a defect, is opposed to the stator core 11, a decrease in insulation performance due to the defect is suppressed. Defects include, for example, bubbles, pinholes, foreign matter, and the like. When the resin member 27 is a potting resin or a soft resin, the effect of protection is remarkable. This suppresses a decrease in insulation performance.

According to the present embodiment, the bus bar 30 can be protected from the cooling medium (fluid) used for the stator 10. The cooling medium reaches the opening 22 or the surface of the resin member 27. At the same time, the cooling medium brings about foreign matter. In the present embodiment, the holder 21 is disposed so that the opening 22 or the resin member 27 faces the one end surface 11 a. Therefore, the strong flow of the cooling medium does not reach the opening 22. Further, foreign matter is prevented from directly reaching and flying toward the opening 22. This suppresses a decrease in insulation performance. In particular, when a liquid such as water or oil is used as the cooling medium, the effect of suppressing the arrival of foreign matter and the effect of protecting the resin member 27 are remarkable.

Second embodiment

This embodiment is a modification of the previous embodiment. In the above embodiment, four phase coils are connected as one phase. Alternatively, one phase can comprise more than one phase coil. For example, there can be two, three, five, six, etc. In the present embodiment, two phase coils are connected.

In fig. 15, one phase is provided by a parallel connection of two phase coils. Fig. 16 shows the stator 10. Fig. 17 shows the bus bar unit 20. Fig. 18 shows a plurality of bus bars 30. Fig. 19 shows the bus bar unit 20. Fig. 20 shows a plurality of bus bars 30. Fig. 21 shows one bus bar. In the present embodiment, half of the bus bar unit 20 of the above-described embodiment is used. The neutral point bus bar 41 is only one. In the present embodiment, the plurality of bus bars 235, 236, 237 are provided by the partial bus bars 35a, 36a, 37a of the above-described embodiment.

Third embodiment

This embodiment is a modification of the previous embodiment. In the above embodiment, the resin members 27 are separately arranged in the plurality of grooves. Alternatively, the resin member 27 may be continuously disposed over a plurality of grooves.

Fig. 22 shows an end face of the bus bar unit 20. The resin member 27 is continuously disposed over the plurality of grooves. Surface 327a extends across partitions 26a, 26b and continues throughout the adjacent trough. In the present embodiment, the boundary 327b is located on the side surface of the outer wall 24 and the side surface of the inner wall 25.

Fourth embodiment

This embodiment is a modification of the previous embodiment. In the above embodiment, the resin member 27 is only potting resin. Alternatively, the resin member 27 may also contain a plurality of resin materials.

Fig. 23 shows an end face of the bus bar unit 20. The assembly stage of the busbar unit 20 includes a stage of applying an adhesive 427 to the inner surface of the holder 21 before the busbar 30 is mounted. The assembly stage of the busbar unit 20 includes a stage of disposing the busbar 30 in the holder 21, a stage of bonding the busbar 30 by the adhesive 427, and a stage of filling the resin member 27 thereafter. A part of the adhesive 427 is pressed out from between the holder 21 and the bus bar 30. The adhesive 427 provides an adhesive resin member. Therefore, the bus bar 30 is covered with both the adhesive 427 and the resin member 27.

Fifth embodiment

This embodiment is a modification of the previous embodiment. In the above embodiment, the bus bar unit 20 accommodates the plurality of bus bars 35, 36, and 37 for crossover. Instead, the bus bar unit 20 may store the neutral point bus bar 41.

Fig. 24 shows the bus bar unit 20. In addition to the above embodiments, holder 21 has partition wall 526 c. A groove for accommodating the neutral point bus bar 41 is defined between the partition wall 526c and the inner wall 25. The neutral point bus bar 41 is accommodated between the partition wall 526c and the inner wall 25.

Further, in the above embodiment, the resin member 27 provides the concave surface 27 a. Alternatively, the resin member 27 may have various surfaces.

In fig. 24, the resin member 27 has a surface 527a inclined with respect to the bottom wall 23. The inclination of the surface 527a depends on the posture of the holder 21 at the time of curing. In addition, the surface 527a is linear.

Sixth embodiment

This embodiment is a modification of the previous embodiment. In the above embodiment, the bus bar unit 20 has the resin member 27. Instead, the bus bar unit 20 may not include the resin member 27.

Fig. 25 is an end face of the bus bar unit 20. The bus bar unit 20 accommodates a plurality of bus bars 35, 36, and 37 in a plurality of slots. The busbar unit 20 has a hollow 628. In the present embodiment, the plurality of partition walls 26a, 26b also provide a long creepage distance between the bus bars 35, 36, 37 arranged in multiple layers in the radial direction. Therefore, the plurality of partition walls 26a, 26b suppress creeping discharge.

Seventh embodiment

This embodiment is a modification of the previous embodiment. In the above embodiment, two neutral point bus bars 41a, 41b are used. Alternatively, a neutral bus may be used.

In fig. 26, the stator coil 12 has one neutral point bus 741. The neutral point bus 741 connects twelve phase coils.

Also, a plurality of phase coils forming one phase may be dispersed within one phase. The four phase coils 712u, 712v, 712w include two sets of phase coils that differ in electrical angle. The two sets of phase coils have electrical angles dispersed in the range of several degrees to several tens of degrees.

Other embodiments

The disclosure in the specification, drawings, and the like are not limited to the illustrated embodiments. The present disclosure includes the illustrated embodiments and variations thereon by those skilled in the art. For example, the present 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 present disclosure may have an additional part that can be added to the embodiment. The present disclosure includes embodiments in which components and/or elements of the embodiments are omitted. The present disclosure includes substitutions or combinations of parts and/or elements between one embodiment and another. The technical scope of the disclosure is not limited to the description of the embodiments. The technical scope of the disclosure should be understood to be expressed by the description of the claims, and also includes all modifications equivalent in meaning and scope to the description of the claims.

The disclosures in the specification and drawings are not limited by the description of the claims. The disclosures in the specification, drawings, and the like include technical ideas described in the claims, and relate to technical ideas that are more diverse and broader than the technical ideas described in the claims. Therefore, various technical ideas can be extracted from the disclosure of the specification, the drawings, and the like without being restricted by the claims.

In the above embodiment, the rotating electrical machine 1 provides a motor generator. Alternatively, the rotating electrical machine 1 may also be provided with an electric motor. In this case, the stator coil 12 is also referred to as an excitation winding. Alternatively, the rotating electrical machine 1 may also provide a generator. In this case, the stator coil 12 is also referred to as an armature winding.

In the above embodiment, the stator coil 12 has the coil side ends 14 and 15 at both ends of the stator core 11. The coil edge 14 is disposed opposite the opening 22. The coil edge 14 can be provided in a variety of ways. In one embodiment, the stator coil 12 may be formed by winding a plurality of continuous conductors. In this case, the coil edge 14 is provided by an aggregate of bent portions of a continuous wire. In another approach, the stator coil 12 is sometimes provided by a plurality of segmented conductors. In this case, the coil edge 14 is provided by a turn of a segment conductor or a joint joining a plurality of segment conductors. The segmented conductor is U-shaped or I-shaped. Such a shape of the coil edge is disclosed in, for example, patent document 2 (japanese patent laid-open No. 2000-166150). The present application refers to the entirety of patent document 2. The plurality of segment conductors may be connected by a plurality of connection conductors disposed at the coil edge 14. Such a shape of the coil edge is disclosed in, for example, patent document 3 (japanese patent laid-open No. 2018-125924). This application is incorporated by reference in its entirety into patent document 3.

In the above embodiment, the holder 21 is made of resin. Alternatively, the holder 21 may be made of an insulating member such as ceramic.

In the above embodiment, the holder 21 is disposed axially outward of the coil edge 14. Alternatively or additionally, the holder 21 may be disposed radially outward of the coil edge 14. In the above embodiment, the holder 21 is opposed to the radially outer corner of the coil edge 14. Alternatively, the holder 21 may be positioned only in the axial direction of the coil edge 14.

In the above embodiment, one phase is provided by a plurality of phase coils connected in parallel. Alternatively, a series connection may be included in one phase. For example, one phase may also be provided by connecting two phase coils connected in parallel and two phase coils connected in parallel in series.

In the above embodiment, the plurality of terminals 31 and 32 of the bus bar unit 20 have a shape called a J-shape or a U-shape. Alternatively, the plurality of terminals 31, 32 can be provided by various shapes such as I-shaped, L-shaped, and the like. For example, the plurality of terminals 31, 32 may be provided only by the first portions 31a, 32a in fig. 11 and 12. In addition, the plurality of terminals 31, 32 may also be provided by the first portions 31a, 32a and the second portions 31b, 32b in fig. 11 and 12.

In the above embodiment, the bus bar unit 20 is supported by the plurality of coil ends 16. Instead, the bus bar unit 20 may be coupled to the stator core 11 or the coil end 14. The holder 21 may have a plurality of leg portions for abutting against the stator core 11 or the coil edge 14, for example. The plurality of legs can be formed by projecting a part of the walls 24, 25, 26 in the axial direction. The plurality of leg portions may be fixed to the stator core 11 or the coil end 14 by a fixing mechanism such as bonding, fastening, or screwing.

In the above embodiment, the coil end 16 and the bus bar unit 20 are depicted as being exposed. Instead, the coil end 16 and/or the busbar unit 20 may have a powder coating layer applied thereto. The powder coating layer can be provided to cover the coil end 16, the joints 17 and 18, and the terminals 31 and 32, for example. The powder coating layer may cover the entire coil edge 14. The powder coating layer may cover the bus bar unit 20.