Rotary Electric Machine and Electric Drive System

An object of the present invention is to provide a rotary electric machine capable of reducing a difference between a height of a first segment conductor and a height of a second segment conductor. A first segment conductor 121 having a first slot pitch and a second segment conductor 122 having a second slot pitch smaller than the first slot pitch are provided, the second segment conductor 122 includes a first leg portion 122A and a second leg portion 122B, the first leg portion 122A includes a slot insertion portion 122A0 and a first linear portion 122A2 connected to the slot insertion portion 122A0 and constituting a coil end portion, the second leg portion 122B includes a slot insertion portion 122B0 and a second linear portion 122B2 connected to the slot insertion portion 122B0 and constituting a coil end portion, and the second linear portion 122B2 is longer than the first linear portion 122A2.

TECHNICAL FIELD

The present invention relates to a rotary electric machine and an electric drive system using the rotary electric machine.

BACKGROUND ART

As a background art of the present technical field, a rotary electric machine described in JP 2020-54052 A (PTL 1) is known. A stator of the rotary electric machine in PTL 1 includes a stator core and a coil wound around the stator core. The coil includes a basic coil segment having a pair of first leg portions and a first crossover portion disposed on a side of a first end face of the stator core, and a crossover coil segment having a pair of second leg portions and a second crossover portion disposed such that the first crossover portion is located between the second crossover portion and the first end face (see abstract). Further, PTL 1 describes a configuration where the basic coil segment includes a main coil segment and a sub coil segment, the main coil segment is inserted into two slots in which the pair of first leg portions are located at a distance of six pitches, and the sub coil segment is inserted into two slots in which the pair of first leg portions are located at a distance of five pitches (see paragraph 0023 andFIG.4). In the stator of the rotary electric machine in PTL 1, a plurality of main coil segments and one sub coil segment are connected in series to constitute one coil constituent, and a plurality of (four) coil constituents is disposed in a radial direction of the stator core (see paragraph 0022 andFIG.4).

CITATION LIST

Patent Literature

SUMMARY OF INVENTION

Technical Problem

The main coil segments and the sub coil segment in PTL 1 are hereinafter referred to as segment conductors for description. If necessary, the main coil segments are called first segment conductors, and the sub coil segment is called a second segment conductor to be distinguished from each other.

In the case of manufacturing the first segment conductors and the second segment conductor having different slot pitches, it is not preferable that a bending angle between the first leg portion and an oblique side portion connecting the first leg portion and the second leg portion and a bending angle between the oblique side portion and the second leg portion are changed between the first segment conductors and the second segment conductor because the number of inspections associated with bending processing increases. In a case where the bending angle between the oblique side portion and the first leg portion and the bending angle between the oblique side portion and the second leg portion are not changed between the first segment conductors and the second segment conductor, the height of each first segment conductor and the height of the second segment conductor are different from each other. This causes a problem that a jig used in work of winding the coil around the stator core using each first segment conductor and the second segment conductor becomes complicated or the winding work becomes complicated, thus making an improvement in the bending accuracy of the segment conductors difficult.

An object of the present invention is to provide a rotary electric machine capable of reducing a difference between a height of a first segment conductor and a height of a second segment conductor.

Solution to Problem

In order to achieve the above object, a rotary electric machine of the present invention includes a stator including a stator core including a plurality of slots; and a coil wound around the stator core, the coil including a plurality of segment conductors each having slot insertion portions disposed respectively inside the plurality of slots and a first coil end portion protruding from one end surface in an axial direction with respect to the stator core, and a rotor disposed with a gap being spaced from the stator. The first coil end portion includes linear portions connected respectively to the slot insertion portions and oblique side portions having a chevron shape with center portions being apexes. The plurality of segment conductors includes a first segment conductor inserted into two of the plurality of slots arranged at a first slot pitch and a second segment conductor inserted into two of the plurality of slots arranged at a second slot pitch smaller than the first slot pitch. The second segment conductor has a second linear portion serving as the linear portion on one of the two slots and being longer than a first linear portion serving as the linear portion on the other one of the two slots. The center portion of the first segment conductor has a protruding height from the end surface of the stator core, the protruding height being substantially equal to a protruding height from the end surface of the stator core at the center portion of the second segment conductor.

Advantageous Effects of Invention

According to the present invention, it is possible to provide a rotary electric machine capable of reducing a difference between a height of a first segment conductor and a height of a second segment conductor.

Problems, configurations, and effects other than those described above will be clarified by the following description of embodiments.

DESCRIPTION OF EMBODIMENTS

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The same reference numerals are given to the same configurations in the drawings to avoid duplication of description. Further, in a case where the same reference numerals are used but contents different from those in other drawings are included, the different portions will be described.

In the following description, a radial direction of a rotor30of a rotary electric machine1is indicated by r, a direction (axial direction) along a rotation shaft32of the rotor30is indicated by z, and a rotation direction of the rotor30is indicated by θ. Further, an axis line (central axis line) passing through the center of the rotation shaft32is indicated by Ax. That is, the axial direction coincides with the direction along the central axis line Ax of the rotation shaft22. The rotation direction θ coincides with a circumferential direction around the central axis line Ax.

In the following description, an up-and-down direction, a vertical direction, and a horizontal direction may be designated to be described. These directions are directions set based on the respective drawings, and do not designate the up-and-down direction, the vertical direction, and the horizontal direction in the mounted state of the rotary electric machine1. Note that a cross section of the rotary electric machine1cut in a direction vertical to the axial direction is referred to as a lateral cross section, and a cross section of the rotary electric machine1cut in the axial direction is referred to as a longitudinal cross section (r-z cross section).

First Embodiment

The rotary electric machine1according to an embodiment of the present invention will be described with reference toFIGS.1to3.FIG.1is a cross-sectional view (longitudinal cross-sectional view) parallel to the center axis line Ax and including the center axis line Ax of a rotary electric machine1of the present invention.FIG.2is a diagram illustrating a stator core11constituting a stator10of the rotary electric machine1of the present invention, and is a plan view of the stator core11as viewed from the axial direction.FIG.3is a diagram illustrating a rotor core31constituting a rotor30of the rotary electric machine1of the present invention, and is a plan view of the rotor core31as viewed from the axial direction. InFIG.3, illustration of the rotation shaft32is omitted.

The rotary electric machine1of the present embodiment can be used, for example, as a traveling motor of an electric vehicle that travels using power of only the rotary electric machine or a hybrid electric vehicle that is driven by both an engine and the rotary electric machine.

As illustrated inFIG.1, the rotary electric machine1includes the stator10, the rotor30, and a housing50. The stator10is held inside the housing50and includes the stator core11and a stator winding (coil)12.

The stator core11is a component of the stator10, and is configured by laminating electromagnetic steel sheets (thin plates). As illustrated inFIG.2, the stator core11includes an annular yoke113, a plurality of teeth111protruding from the yoke113toward the rotor30in a comb shape, and a plurality of slots112each formed between the teeth111. The slots112constitute a storage space for the coil12. In the present embodiment, the stator core11having 48 slots is illustrated.

The coil12inserted into the slots112and wound around the stator core11includes three-phase U, V, and W windings.

As illustrated inFIG.1, the rotor30is rotatably disposed on the inner circumferential side of the stator core11via a gap Gp. The rotor30includes the rotor core31fixed to the rotation shaft32, a plurality of permanent magnets33fixed to the rotor core31and configuring magnetic poles, and non-magnetic end boards34A and34B attached to both end surfaces of the rotor core31in the axial direction. The rotor30is rotatably disposed by the rotation shaft32being pivotally supported by bearings61A and61B provided on end brackets51A and51B. The rotation shaft31may also be referred to as a drive shaft or a shaft.

The rotor core31mainly serves as a magnetic path and a strength member, and is formed by laminating thin plate-shaped steel sheets. The laminating direction of the steel sheets (laminated steel sheets) coincides with the axial direction. The end boards34A and34B are structural members disposed at both axial ends of the rotor core32in order to fix the steel sheets forming the rotor core32in the axial direction. Alternatively, the laminated steel sheets may be fixed by welding, and in this case, the end boards34A and34B may not be used. Electromagnetic steel sheets are usually used as the laminated steel sheets.

The housing50includes the pair of end brackets51A and51B having the bearings61A and61B, and a side surface portion52, and houses the stator10and the rotor30. The rotor30formed integrally with the rotation shaft32is rotatably held by the housing50via the bearings61A and61B.

In the present embodiment, the rotary electric machine1is assumed to be driven by a three-phase alternating current. For this reason, the rotation shaft32includes a resolver (rotation angle sensor)35that detects a position of a pole and a rotation speed of the rotor30. Based on an output from the resolver35, a control signal and a drive signal for a power module, not illustrated, performing a switching operation are generated in a control circuit and a drive circuit, not illustrated.

In the present embodiment, an embedded magnet motor is exemplified as the rotary electric machine1, but the rotary electric machine1is not limited to the embedded magnet motor. As illustrated inFIG.3, the rotor core31is provided with a plurality of magnet housings36along the circumferential direction, and the magnet37is inserted and fixed in a hole36. The magnet housings36are configured by holes (magnet insertion holes).

In the present embodiment, the configuration where one pole includes three magnets37is exemplified, but the number of the magnets37configuring one pole is not limited to three. For example, one pole may be configured by one flat magnet, or by disposing two flat magnets in a V shape.

The rotor30in the present embodiment has eight magnetic poles (the number of poles=8). As described above, the stator10has forty-eight slots (the number of slots=48), and the three-phase coil12is wound (the number of phases=3). The rotary electric machine1of the present embodiment is a rotary electric machine of three phases, eight poles, and forty-eight slots. In this case, the number of slots per pole and per phase (NSPP) obtained by (the number of slots)/((the number of poles)×(the number of phases)) is two.

Next, the configuration of coil segments121and122constituting the coil12of the present embodiment will be described with reference toFIGS.4A to4C.

FIG.4Ais a view illustrating an assembled state of the first coil segment121and the second coil segment122constituting the coil12to the stator core11in one embodiment of the coil12of the present invention.

The coil12is wound around the stator core11including the plurality of segment conductors121and122. The coil12is disposed as a wave winding across the plurality of slots and mechanically are put around the stator core11once. The segment conductor is a coil member having a rectangular cross section, and an insulating layer is provided on the outer circumference by enamel or the like.

The plurality of segment conductors121and122includes the first segment conductor121inserted into two slots112arranged with a first slot pitch and the second segment conductor122inserted into two slots arranged with a second slot pitch smaller than the first slot pitch. The plurality of the first segment conductors121is consecutively provided at the first slot pitch. The second segment conductor122is provided at the second slot pitch as the last segment conductor following the plurality of first segment conductors121in order to adjust the number of slots not to be insufficient.

In the present embodiment, as the rotary electric machine1with 8 poles and 48 slots, a configuration where the first slot pitch is set to 6 and the second slot pitch is set to 5 is exemplified.

Here, the first segment conductor121and the second segment conductor122will be described with reference toFIGS.4B and4C.FIG.4Bis a plan view schematically illustrating a shape characteristic of the first segment conductor121before assembling to the stator core11.FIG.4Cis a plan view schematically illustrating a shape characteristic of the second segment conductor122before assembling to the stator core11.

As illustrated inFIG.4B, the first segment conductor121includes a pair of first leg portion121A and second leg portion121B, and an oblique side portion121C formed in a substantially chevron shape with a center portion being an apex121CC and connecting the first leg portion121A and the second leg portion121B. That is, the oblique side portion121C has a first oblique side portion121CA descending from the apex121CC to the side of the first leg portion121A and a second oblique side portion121CB descending from the apex121CC to the side of the second leg portion121B with the apex121CC being a boundary. The first oblique side portion121CA is bent at an angle θ121A (=θ1) at a bending portion121A1with respect to the first leg portion121A. The second oblique side portion121CB is bent at an angle θ121B (=θ1) at a bending portion121B1with respect to the second leg portion121B.

A length k121A of the first leg portion121A and a length k121B of the second leg portion121B are k1 and equal to each other. The angle θ121A between the first oblique side portion121CA and the first leg portion121A and the angle θ121B between the second oblique side portion121CB and the second leg portion121B are θ1and equal to each other. The first segment conductor121has a space d1 that houses six teeth111(seeFIG.2) between the pair of first leg portion121A and second leg portion121B in order to be inserted into two slots arranged at the first slot pitch.

Reference numeral121xdenotes a center line of the first segment conductor121passing through the apex121CC of the oblique side portion121C. A distance between the first leg portion121A and the center line121xand a distance between a second leg portion122A and the center line121xare both d2 and equal to each other.

As illustrated inFIG.4C, the second segment conductor122includes a pair of first leg portion122A and second leg portion122B, and an oblique side portion122C connecting the first leg portion122A and the second leg portion122B. The oblique side portion122C is formed in a substantially chevron shape having an apex122CC, and has a first oblique side portion122CA descending from the apex121CC to the side of the first leg portion122A and a second oblique side portion122CB descending from the apex122CC to the side of the second leg portion122B with the apex122CC being a boundary. The first oblique side portion122CA is bent at an angle θ122A (=θ1) at a bending portion122A1with respect to the first leg portion122A. The second oblique side portion122CB is bent at an angle θ122B (=θ1) at a bending portion122B1with respect to the second leg portion122B.

The second segment conductor122has a space d3 that houses five teeth111(seeFIG.2) between the pair of the first leg portion122A and the second leg portion122B in order to be inserted into two slots arranged at the second slot pitch. That is, d3 is smaller than d1 (d3<d1).

On the other hand, the angle θ122A formed by the first oblique side portion122CA with the first leg portion122A and the angle θ122B formed by the second oblique side portion122C with the second leg portion122B are both θ1and equal to each other. The angle θ122A and the angle θ122B in the second segment conductor122are equal to the angle θ121A and the angle θ121B in the first segment conductor121.

Therefore, the length k122B of the second leg portion122B is k2, which is longer than a length k122A (=k1) of the first leg portion122A by a difference Δk between k2 and k1 (k2>k1). In this case, the length k122A of the first leg portion122A of the second segment conductor122is k1, and equal to the length k121A of the first leg portion121A and the length k121B of the second leg portion121B of the first segment conductor121.

Although122xrepresents a line segment passing through the apex122CC of the oblique side portion122C, a distance d4 between the second leg portion122A and the line segment122xis shorter than a distance d2 between the first leg portion122A and the line segment122x. Note that the distance d2 between the first leg portion122A and the line segment122xis equal to the distance d2 between the first leg portion121A and the center line121xin the first segment conductor121.

In addition, as illustrated inFIGS.4B and4C, a twisted portion121CD is provided in the oblique side portion121C of the first segment conductor121, and a twisted portion122CD in the oblique side portion122C of the second segment conductor122. The first segment conductor121and the second segment conductor122are disposed such that the plurality of segment conductors overlaps in a radial direction. At this time, the twisted portions (radial bending portions)121CD and122CD as indicated by a broken line T inFIG.7are formed in the segment conductors so as to avoid interference between the plurality of segment conductors.

Returning toFIG.4Aagain, the description will be given. The first segment conductor121and the second segment conductor122in the states illustrated inFIGS.4B and4Care each inserted into the slots112of the fixing core11. In the present embodiment, they are inserted into the slots112from an end face11S1of the fixing core11.

In the first leg portion121A of the first segment conductor121inserted into the slots112, a portion121A4on a tip (lower end)121A6side of the first leg portion121A is bent at a bending portion121A3toward a side opposite from the second leg portion121B side with respect to a slot insertion portion121A0provided inside the slot112. Further, in the second leg portion121B of the first segment conductor121, a portion121B4on a tip (lower end)121B6side of the second leg portion121B is bent at a bending portion121B3toward a side opposite from the first leg portion121A with respect to a slot insertion portion121B0provided inside the slot112. The portion121A4bent at the bending portion121A3constitutes a third oblique side portion of the first segment conductor121, and the portion121B4bent at the bending portion121B3constitutes a fourth oblique side portion of the first segment conductor121.

Further, in the first leg portion121A, the tip (lower end)121A6side of the first leg portion121A is bent in a direction along the slot insertion portion121A0at a bending portion121A5with respect to the third oblique side portion121A4. In the second leg portion121B, the tip (lower end)121B6side of the second leg portion121B is bent in a direction along the slot insertion portion121B0at a bending portion121B5with respect to the fourth oblique side portion121B4.

In the first leg portion122A of the second segment conductor122inserted into the slot112, a portion122A4on a tip (lower end)122A6side of the first leg portion122A is bent at a bending portion122A3toward a side opposite from the second leg portion122B with respect to a slot insertion portion122A0provided inside the slot112. Further, in the second leg portion122B of the second segment conductor122, a portion122B4on a tip (lower end)122B6side of the second leg portion122B is bent at a bending portion122B3toward a side opposite from the first leg portion122A with respect to a slot insertion portion122B0provided inside the slot112. The portion122A4bent at the bending portion122A3constitutes a third oblique side portion of the second segment conductor122, and the portion122B4bent at the bending portion122B3constitutes a fourth oblique side portion of the second segment conductor122.

Further, in the first leg portion122A, the tip (lower end)122A6side of the first leg portion122A is bent in a direction along the slot insertion portion122A0at a bending portion122A5with respect to the third oblique side portion122A4. In the second leg portion122B, the tip (lower end)122B6side of the second leg portion122B is bent in a direction along the slot insertion portion122B0at a bending portion122B5with respect to the fourth oblique side portion122B4.

A portion between the bending portion121A5and the tip121A6in the first leg portion121A of the first segment conductor121is welded to a portion on the tip121B6side in the second leg portion121B of a different adjacent first segment conductor121. On the other hand, a portion between the bending portion121B5and tip121B6in the second leg portion121B is welded to a portion between the bending portion122A5and the tip122A6side in the first leg portion122A of the adjacent second segment conductor122.

The coil12includes the slot insertion portion121A0disposed inside the slot112and a first coil end portion protruding from the end face11S1of the stator core11. The first coil end portion is mainly constituted by the oblique side portions121C and122C of the segment conductors121and122, and includes linear portions121A2,121B2,122A2, and122B2connected to the slot insertion portions121A0,121B0,122A0, and122B0.

The linear portion121A2is a portion constituting the first leg portion121A of the first segment conductor121together with the slot insertion portion121A0(a first linear portion of the first segment conductor121). The linear portion121B2is a portion constituting the second leg portion121B of the first segment conductor121together with the slot insertion portion121B0(a first linear portion of the first segment conductor121). The linear portion122A2is a portion constituting the first leg portion122A of the second segment conductor122together with the slot insertion portion122A0(a first linear portion of the second segment conductor122). The linear portion122B2is a portion constituting the second leg portion122B of the second segment conductor122together with the slot insertion portion122B0(a second linear portion of the second segment conductor122).

In the first coil end portion, one of the first segment conductor121and the second segment conductor122constitutes a coil end portion alone.

The coil12has a second coil end portion protruding from an end surface11S2of the stator core11on the side opposite from the side where the first coil end portion of the stator core11is formed. In the second coil end portion, the coil end portion is configured by connecting the first leg portion121A and the second leg portion121B of the two first segment conductors121, or by connecting the second leg portion121B of the first segment conductor121and the first leg portion122A of the second segment conductor122. The third oblique side portion121A4and the fourth oblique side portion121B4of the first segment conductor121and the third oblique side portion122A4and the fourth oblique side portion122B4of the second segment conductor122are configured in the second coil end portions. Further, the welded portion W of the two segment conductors is formed in the second coil end portion.

In the second segment conductor122, the second linear portion122B2forming the linear portion on the one slot112side is longer than the first linear portion122A2forming the linear portion on the other slot112side. In the second linear portion122B2of the second segment conductor122, a portion exposed to the outside of the stator core11from the end surface11S1of the stator core11in the second leg portion122B (seeFIG.4C), that is, a height from the end surface11S1to the bending portion122B1is h22, and is larger than a height h21from the end surface11S1to the bending portion122A1in the first linear portion122A2of the second segment conductor122(h22>h21). Note that the height h21from the end surface11S1to the bending portion122A1in the first linear portion122A2of the second segment conductor122is equal to the height h21from the end surface11S1to the bending portion121A1in the first linear portion121A2of the first segment conductor121and the height h21from the end surface11S1to the bending portion121B1in the second linear portion121B2of the first segment conductor121.

Further, a protruding height h121from the end surface11S1of the stator core11in the first coil end portion of the first segment conductor121is equal to a protruding height h122from the end surface11S1of the stator core11in the first coil end portion of the second segment conductor122(h121=h122=h1).

The stator10of the rotary electric machine1of the present embodiment has the following features.

The rotary electric machine1includes the stator10including the stator core11including the plurality of slots112, and the coil12wound around the stator core11, the coil including the plurality of segment conductors121and122, the segment conductor121and122having slot insertion portions121A0,121B0,122A0, and122B0, the slot insertion portions121A0,121B0,122A0, and122B0being disposed respectively inside the plurality of slots112, the plurality of segment conductors121and122each having a coil end portion (first coil end portion) protruding from the end surface11S1of the stator core11; and a rotor30disposed with a gap being spaced from the stator10. The coil end portion includes linear portions121A2,121B2,122A2, and122B2connected respectively to the slot insertion portions121A0,121B0,122A0, and122B0, and oblique side portions121C and122C having a chevron shape with center portions being apexes121CC and122CC. The plurality of segment conductors121and122includes a first segment conductor121inserted into two of the plurality of slots112arranged at a first slot pitch and a second segment conductor122inserted into two of the plurality of slots112arranged at a second slot pitch smaller than the first slot pitch. The second segment conductor122has a first linear portion122A2and a second linear portion122B2, the second linear portion122B2serving as a linear portion on one of the two slots and being longer than the first linear portion122A2serving as a linear portion on the other one of the two slots. The center portion of the first segment conductor121has a protruding height h121from the end surface11S1of the stator core11, the protruding height h121being equal to a protruding height h122from the end surface11S1of the stator core11at the center portion of the second segment conductor122.

According to the present embodiment, since the heights of the first coil end portions are aligned, positioning accuracy of the coil12by a jig70(seeFIG.4A), that is, the first segment121and the second segment conductor122is improved, and accurate bending can be performed on the first segment121and the second segment conductor122. In addition, when the first segment121and the second segment conductor122are positioned and bent by the jig70, the first segment121and the second segment conductor122are less likely to move in the axial direction, and damage of an insulating film of the first segment121and the second segment conductor122(movement of insulating paper) can be reduced. Further, since the processing accuracy at the time of bending the first segment121and the second segment conductor122is improved, it is possible to reduce the occurrence of defects at the time of welding the welded portion W.

In the present embodiment, since the bending angles (θ121A, θ121B, θ122A, and θ122B) of the first segment conductor121and the second segment conductor122are equal to each other, an increase in the number of inspections can be reduced. Further, variations in winding resistance and the like can be reduced, a yield rate can be improved, and reliability can be improved.

The rotary electric machine1of the present embodiment includes the stator10of the rotary electric machine1described above and the rotor30disposed, with a gap, being spaced from the stator10, and the number of slots per pole per phase (NSPP) is 2. In this case, the coil12includes the first segment conductor121and the second segment conductor122serving as an odd-shape coil member with respect to the first segment conductor121.

Next, a lead segment conductor123will be described with reference toFIGS.5and6.FIG.5is a perspective view illustrating an appearance of the coil end portion.FIG.6is a plan view illustrating a shape of the lead segment conductor123.

The coil12includes the lead segment conductor123constituting a lead wire. The lead segment conductor123includes a first lead portion123A housed in the slot112, a second lead portion123B positioned at the first coil end portion, and a bent portion123C provided between the first lead portion123A and the second lead portion123B. The first lead portion123A has a linear shape parallel to the axial direction. The second lead portion123B is connected to the first lead portion123A via the bent portion123C and has a linear shape parallel to the axial direction.

The positions of the first lead portion123A and the second lead portion123B in the radial direction with respect to the stator core11are different so that the second lead portion123B is positioned on an inner circumferential side with respect to the first lead portion123A. Further, the lead segment conductor123is disposed closer to the second linear portion122B than the first linear portion122A of the second segment conductor122.

That is, the rotary electric machine1of the present embodiment has the following features.

The coil12includes the lead segment conductor123constituting the lead wire, and the lead segment conductor123includes the first lead portion123A that is housed in the slot112and has a linear shape parallel to the axial direction, and the second lead portion123B that is connected to the first lead portion123A via the bent portion123C and is positioned on the first coil end portion to have a linear shape. The positions of the first lead portion123A and the second lead portion123B are different in the radial direction with respect to the stator core11so that the second lead portion123B is positioned on the inner circumferential side with respect to the first lead portion123A. The lead segment conductor123is disposed closer to the second linear portion122B than the first linear portion122A of the second segment conductor122.

As a result, the bent portion123C of the lead segment conductor123can be disposed below the second oblique side portion122CB of the second segment conductor122and between the end surface11S1of the stator core11and the second oblique side portion122CB. A gap (a gap based on Δk inFIG.4C) larger than the gap below the first oblique side portion122CA is formed below the second oblique side portion122CB of the second segment conductor122, and interference between the second segment conductor122and the lead segment conductor123can be prevented.

FIG.7is a plan view of the stator10of the rotary electric machine1as viewed from a first coil end portion side (end surface11S1side).

In the rotary electric machine1of the present embodiment, the lead segment conductor123includes inner circumferential lead segment conductors123-1to123-6housed in the slots112at the position on the inner circumferential side of the stator core11, and outer circumferential lead segment conductors123-7to123-12housed in the slots112at the position on the outer circumferential side of the stator core11.

By adopting the above-described disposition for the second segment conductor122in at least one of the lead segment conductors123-1to123-12, the interference between the second segment conductor122and the lead segment conductor123can be prevented at the portion of the lead segment conductor123. By adopting the above-described disposition for the second segment conductor122in all the lead segment conductors123-1to123-12, the height of the coil end portion (first coil end portion) can be reduced, and thus the rotary electric machine1can be downsized.

FIG.8is a partial cross-sectional view of the stator core11into which the first segment conductor121and the second segment conductor122are inserted.

Inside the slots, an insulator80is disposed between the stator core11and the slot insertion portions121A0and121B0of the first segment conductor121and between the two slot insertion portions121A0adjacent to each other. The insulator80is made of, for example, varnish. Similarly to the first segment conductor121, the insulator80is disposed between the stator core11and the slot insertion portions122A0and122B0of the second segment conductor122and between the two slot insertion portions122A0and122B0adjacent to each other.

That is, in the rotary electric machine1of the present embodiment, the insulator80is disposed inside each of the slots112between the stator core11and the slot insertion portions121A0,121B0,122A0, and122B0of the segment conductors121and122and between the two slot insertion portions121A0and121B0and between the two slot insertion portions122A0and122B0adjacent to each other.

The insulator80is made of a non-conductive material such as varnish or insulating paper. Although the segment conductors121and122are insulated by enamels or the like, the insulation of the stator core11can be further improved by disposing the insulator80, and the reliability of the rotary electric machine1can be improved.

FIG.9is a diagram describing an embodiment where the stator core11is manufactured by laminating thin plate-shaped steel sheets, and the laminated steel sheets are joined by welding.

The stator core11of the present embodiment is configured by laminating steel sheets (for example, electromagnetic steel sheets)11P. The laminated steel sheets have a welded part11wwelded and fixed. The welded part11W of the stator core11is disposed closer to the second linear portion than to the first linear portion121A of the second segment conductor122.

That is, in the rotary electric machine1of the present embodiment, the stator core11has the welded part11W where the steel sheets11P are laminated and the laminated steel sheets11P are welded and fixed, and the welded part11W of the stator core11is disposed closer to the second linear portion122B2than the first linear portion122A2of the second segment conductor122.

The welded part11W may expand due to heat input during welding. In the present embodiment, since a gap h5formed between the second oblique side portion122CB and the end surface11S1of the stator core11on the second linear portion122B2side is larger than a gap h6formed between the first oblique side portion122CA and the end surface11S1of the stator core11on the first linear portion122A2side of the second segment conductor122, interference with the expanding welded part11W can be easily avoided. Alternatively, even when the welded part11W expands, it is easy to dispose the lead segment conductors123-1to123-12and the like between the expanded end surface11S1and the second oblique side portion122CB.

FIG.10is a view describing an embodiment where the twisted portions121CD and122CD inFIGS.4A and4Care formed in the welded portion W.

The segment conductors121and122have second coil end portions121A6,121B6,122A6, and122B6protruding from the end surface11S2opposite from the end surface11S1of the stator core11with respect to the stator core11. The second coil end portions121A6,121B6,122A6, and122B6of the segment conductors121and122are connected respectively to the second coil end portions121A6,121B6,122A6, and122B6of different segment conductors121and122by welding on the side of the end surface11S2on the opposite side of the stator core11.

The present embodiment has described that the first segment conductor121and the second segment conductor122can be positioned accurately by the jig70, and the bending processing for the first segment conductor121and the second segment conductor122can be performed accurately. In the present embodiment, since the position of the welded portion W can be determined accurately, the twisted portions121CD and122CD provided in the oblique side portion121C of the first segment conductor121and the oblique side portion122C of the second segment conductor122can be provided in the welded portion W. That is, the twisted portions121CD and122CD that are bent in the radial direction can be provided at the joint portion W formed by welding the second coil end portions121A6,121B6,122A6, and122B6of the segment conductors121and122to the second coil end portions121A6,121B6,122A6, and122B6of different segment conductors121and122.

That is, in the present embodiment, since the legs of the segment conductors121and122on the welded portion W side are aligned, the torsion of the coil12can be provided on the welded portion W side, and thus the weldability of the coil12can be improved.

Therefore, the rotary electric machine1of the present embodiment has the following features.

The segment conductors121and122have the second coil end portions121A6,121B6,122A6, and122B6protruding from the end surface11S2opposite from the end surface11S1of the stator core11with respect to the stator core11. The second coil end portions121A6,121B6,122A6, and122B6of the segment conductors121and122are connected to the second coil end portions121A6,121B6,122A6, and122B6of different segment conductors121and122by welding on the side of the end surface11S2on the opposite side of the stator core11. The twisted portions121CD and122CD that are bent in the radial direction are provided at the joint portion formed by welding the second coil end portions121A6,121B6,122A6, and122B6of the segment conductors121and122to the second coil end portions121A6,121B6,122A6, and122B6of the different segment conductors121and122.

In the present embodiment, since the degree of freedom in the disposition of the twisted portions121CD and122CD is increased, the degree of freedom in designing the rotary electric machine1is improved.

Second Embodiment

The rotary electric machine1according to the present embodiment is applicable to a pure electric vehicle that travels with power of only the rotary electric machine or a hybrid electric vehicle that is driven by both an engine and the rotary electric machine, but a hybrid electric vehicle will be described as an example.

An engine520, a first rotary electric machine1-1, a second rotary electric machine1-2, and a battery580are mounted on a vehicle500. The battery580supplies DC power to the first rotary electric machine1-1and the second rotary electric machine1-2via a power conversion device600in a case where driving force by the first rotary electric machine1-1and the second rotary electric machine1-2is required for the vehicle500. Further, the battery580receives DC power from the first rotary electric machine1-1and the second rotary electric machine1-2during regenerative traveling. Transmission and reception of DC power between the battery580and the first rotary electric machine1-1or the second rotary electric machine1-2is performed via the power conversion device600. Although not illustrated, a battery that supplies low voltage power (for example, 14 volt system power) is mounted on the vehicle500, and supplies DC power to a control circuit, described below.

Note that the first rotary electric machine1-1and the second rotary electric machine1-2have substantially the same structure, and can be configured by the rotary electric machine1, described above. However, both the first rotary electric machine1-1and the second rotary electric machine1-2do not need to have the structure related to the first segment conductor121and the second segment conductor122, and only one of them may have this structure.

A rotation torque generated by the engine520, the first rotary electric machine1-1or the second rotary electric machine1-2is transmitted to a front wheel510via a transmission530and a differential gear560. The transmission530is controlled by a transmission control device534. The engine520is controlled by an engine control device524. The battery580is controlled by a battery control device584. The transmission control device534, the engine control device524, the battery control device584, the power conversion device600, and an integrated control device570are connected to each other via a communication line574.

The integrated control device570is a control device higher than the transmission control device534, the engine control device524, the power conversion device600, and the battery control device584, and receives information representing respective states of the transmission control device534, the engine control device524, the power conversion device600, and the battery control device584from these devices via the communication line574. The integrated control device570calculates control commands for the respective devices based on the acquired information. The calculated control commands are transmitted to the devices via the communication line574.

The battery580is configured by a secondary battery such as a lithium ion battery or a nickel hydrogen battery, and outputs high voltage DC power of 250 V to 600 V or higher. The battery control device584outputs the charge and discharge status of the battery580and the state of each unit cell battery configuring the battery580to the integrated control device570via the communication line574.

When determining that the battery580needs to be charged, based on the information from the battery control device584, the integrated control device570instructs the power conversion device600to perform a power generation operation. In addition, the integrated control device570mainly performs management of output torques from the engine520, the first rotary electric machine1-1, and the second rotary electric machine1-2, calculation processing for a total torque and a torque distribution ratio of the output torque from the engine520and the output torques from the first rotary electric machine1-1and the second rotary electric machine1-2, and transmits control commands based on a result of the calculation processing to the transmission control device534, the engine control device524, and the power conversion device600. The power conversion device600controls the first rotary electric machine1-1and the second rotary electric machine1-2so as to generate torque outputs or generated power according to the commands, based on a torque command from the integrated control device570.

The power conversion device600is provided with a power semiconductor constituting an inverter circuit for operating the first rotary electric machine1-1and the second rotary electric machine1-2. The power conversion device600controls a switching operation of the power semiconductor based on a command from the integrated control device570. By the switching operation of the power semiconductor, the first rotary electric machine1-1and the second rotary electric machine1-2are operated as an electric motor or a generator.

In a case where the first rotary electric machine1-1and the second rotary electric machine1-2are operated as electric motors, DC power from the high-voltage battery580is supplied to a DC terminal of an inverter of the power conversion device600. The power conversion device600controls the switching operation of the power semiconductor to convert the supplied DC power into three-phase AC power, and supplies the converted power to the first rotary electric machine1-1and the second rotary electric machine1-2. On the other hand, in a case where the first rotary electric machine1-1and the second rotary electric machine1-2are operated as generators, the rotors of the first rotary electric machine1-1and the second rotary electric machine1-1are rotationally driven by a rotational torque externally applied, and three-phase AC power is generated in the stator windings of the first rotary electric machine1-1and the second rotary electric machine1-2. The generated three-phase AC power is converted into DC power by the power conversion device600, and this DC power is supplied to the battery580, and thus the high-voltage battery580is charged.

In the present embodiment, as the electric drive system including the rotary electric machines1-1and1-2that generate the driving force of the vehicle and the power conversion device600, it is preferable to provide the rotary electric machine1having the stator30where the coil12includes the first segment conductor121and the second segment conductor122, and the rotor30rotatably disposed on the inner circumferential side of the stator core11via the gap.

That is, the electric drive system of the present embodiment that includes a rotary electric machine1that generates drive force of a vehicle and a power conversion device includes, as the rotary electric machine, the rotary electric machine of the present embodiment.

The rotary electric machine1of the present embodiment can be reduced in size and cost, and is suitable for application to a motor for a main machine for an automobile.

Note that the present invention is not limited to the above embodiments, and various modifications are possible. For example, the above-described embodiments have been described in detail for easy understanding of the present invention, and the present invention is not necessarily limited to an aspect including all the described configurations. In addition, a part of the configuration in each embodiment can be deleted or another configuration can be added.

REFERENCE SIGNS LIST

1rotary electric machine10stator11stator core11P steel sheet11S1end surface of stator core1111W welded part12coil80insulator112slot121segment conductor (first segment conductor)122segment conductor (second segment conductor)121A0,121B0,122A0,122B0slot insertion portion of segment conductor121A2,121B2,122A2,122B2linear portion of coil end portion121A6,121B6,122A6,122B6second coil end portion121C,122C oblique side portion121CC,122CC apex of coil end portion121CD,122CD twisted portion122A2first linear portion122B2second linear portion123lead segment conductor123-1to123-6inner circumferential lead segment conductor123-7to123-12outer circumferential lead segment conductor123A first lead portion123B second lead portion123C bent portion