Rotating electrical machine and vehicle equipped with this rotating electrical machine

Abstract

To provide a rotary electric machine which suppresses increase in cost or physical scale.SOLUTION: Each of first segment coils 510 and each of second segment coils 520 comprise: transfer parts 200 and 210 which are formed so as to transfer in a radial direction of a rotary electric machine; and tilt parts 511 and 522 which are formed while being tilted with respect to an end face of a stator core 101. One of the first segment coils 510 is disposed in a slot 410 and the other is disposed in a slot 420, One of the second segment coils 520 is disposed radially outside of the first segment coil 510 in the slot 420, and the other is disposed and transferred radially inside of the first segment coil 510 in the slot 420. The tilt part 511 of the first segment coil and the tilt part 522 of the second segment coil 520 are tilted at different angles with respect to the end face of the stator core 101.SELECTED DRAWING: Figure 5B

Description

Technical Field

[0001] The present invention relates to a rotating electric machine mounted on a railway vehicle, an automobile, a construction machine, etc., and a vehicle equipped with this rotating electric machine.

Background Art

[0002] In recent years, miniaturization of motors has been required, and in order to meet this requirement, the drive rotation speed of motors has been increasing. This is an attempt to obtain the same output with a small motor by increasing the rotation speed and decreasing the torque because the motor output is proportional to torque × rotation speed. However, since the power supply frequency of the motor increases with the increase in speed, the AC copper loss of the stator coil increases significantly, leading to a decrease in efficiency and an increase in heat generation. The AC copper loss refers to the loss generated by the deviation of the current distribution in the coil due to the magnetic flux crossing the slot, and the AC copper loss tends to increase as the current, frequency, and conductor cross-sectional area increase.

[0003] In the case of a distributed winding stator widely adopted in drive motors for automobiles, etc., for mass production, a manufacturing method is adopted in which the number of coil turns is suppressed to several turns, and adjacent coils are welded and connected at the end portion in the stator axis direction (Patent Document 1). In order to reduce the AC copper loss with this structure, measures such as configuring each coil per turn with a multi-stage flat rectangular wire are necessary.

[0004] In the manufacturing method described in Patent Document 1, when the coil has multiple stages, there is a drawback that the number of welding points at the coil end connection portion increases and the manufacturing becomes complicated. Furthermore, in Patent Document 1, problems such as insulation film damage and poor welding in the welding process are likely to occur, and ensuring the reliability of the motor becomes an issue.

[0005] As a countermeasure, there is a method of suppressing the increase in the number of welding points by welding multiple-stage coils together. However, in that case, since the multiple-stage coils are electrically short-circuited at the welding points, a circulating current flows through the closed loop formed thereby, and a new problem of increased loss occurs.

[0006] For this reason, a technique has been proposed to suppress the generation of circulating current by transferring (transposing) the coil arrangement (Patent Documents 2 and 3).

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0008] However, in the techniques described in Patent Documents 2 and 3, there are problems such as the need for additional equipment and additional man-hours for transposition, which leads to an increase in manufacturing costs. Also, when transposing at the coil end as in Patent Document 3, there is a problem that the axial height increases at the transposed portion, resulting in an increase in the size of the motor.

[0009] An object of the present invention is to provide a rotating electrical machine capable of suppressing an increase in cost and size, and a vehicle equipped with this rotating electrical machine.

Means for Solving the Problems

[0010] To achieve the above object, the present invention provides a rotating electrical machine including a rotor and a stator, wherein the stator includes a stator core having a plurality of slots and segment coils with a rectangular cross-section formed in a substantially U shape and inserted into the slots. The slots are composed of at least a first slot and a second slot, the segment coils are composed of at least a first segment coil and a second segment coil. Each of the first slot and the second slot has a first layer and a second layer arranged from the radially inner side to the radially outer side of the rotating electrical machine. Each of the first segment coil and the second segment coil includes a slot insertion portion disposed in the first slot and the second slot, a transition portion formed in a region including the apex of the portion protruding from the end face of the stator core and configured to transition in the radial direction of the rotating electrical machine, and an inclined portion formed between the slot insertion portion and the apex and inclined with respect to the end face of the stator core. The first segment coil has one disposed in the first layer of the first slot and the other disposed in the second layer of the second slot. The second segment coil has one disposed radially outside the first segment coil in the first layer of the first slot and the other disposed radially inside the first segment coil in the second layer of the second slot. The transition portions of the first segment coil and the second segment coil are inclined from the first layer to the second layer when viewed axially, and are arranged to intersect at their respective transition portions. The transition portion of the first segment coil is formed to have a larger transition size than the transition portion of the second segment coil. The inclined portion of the first segment coil and the inclined portion of the second segment coil are inclined at different angles with respect to the end face of the stator core. The first segment coil or the second segment coil is configured such that the cross-sectional shape of the transition portion is different from the cross-sectional shape other than the transition portion so that the axial length becomes shorter at the transition portion. The first segment coil and the second segment coil are each configured to be divided so as to face each other in the axial direction of the rotating electrical machine. Each of the divided first segment coil and the second segment coil is provided with a connection portion that is connected within the slot. Each of the connection portions is formed with a stepped portion having an L-shaped stepped shape when viewed in the circumferential direction so as to fit with each other. Each of the stepped portions where the divided first segment coil and the second segment coil face each other in the radial direction is provided with a conductive portion for electrically connecting the divided first segment coil and the second segment coil It is characterized by the above.

Advantages of the Invention

[0011] According to the present invention, it is possible to provide a rotating electrical machine capable of suppressing an increase in cost and size, and a vehicle equipped with this rotating electrical machine.

Brief Description of the Drawings

[0012]

Figure 1A

Figure 1B

Figure 2A

Figure 2B

Figure 3A

Figure 3B

Figure 3C

Figure 4A

Figure 4B

Figure 4C

Figure 5A

Figure 5B

Figure 6A

Figure 6B

Figure 6C

Figure 6D

Figure 7A

Figure 7B

Figure 7C

Figure 8A

Figure 8B

Figure 9A

Figure 9B

Figure 9C

Figure 10A

Figure 10B

Figure 10C

Figure 11A

Figure 11B

Figure 12

Embodiments for Carrying Out the Invention

[0013] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same reference numerals are given to the same components. Their names and functions are the same, and redundant explanations are avoided. In the present invention, the definition of a "coil" is one turn of a tortoise shell coil or one cycle of a wave coil. For example, in a configuration where the coil is wound 4 times, it is expressed as a 4-turn coil. However, in the following description, for the sake of simplicity, basically a single-turn coil (coil per turn) is targeted. Also, when a single-turn coil is composed of a plurality of conductors, each conductor is called a segment coil.

[0014] Also, in the following description, the target is a rotating electrical machine with variable speed drive such as an automobile or a railway vehicle. However, the effects of the present invention are not limited to this and are applicable to all rotating electrical machines including a constant speed. Also, the rotating electrical machine may be an induction machine, a permanent magnet synchronous machine, a wound synchronous machine, a synchronous reluctance rotating machine, or a switched reluctance rotating machine. Also, in the following description, an inner-rotating type rotating electrical machine is targeted, but an outer-rotating type rotating electrical machine may also be used. Also, the material of the coil may be copper, aluminum, or other conductive materials. Also, although the cross-sectional shape of the coil is described with respect to a rectangular wire, the effects of the present invention are not limited to this and may be composed of a single or a plurality of round wires, or other shapes, and are applicable to all configurations in which AC copper loss becomes significant.

Embodiment

[0015] Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. 1 to 6. FIG. 1A is a view of a coil per turn in the prior art as seen from the axial direction of the rotating electrical machine. FIG. 1B is a cross-sectional view taken along line IB-IB in FIG. 1A.

[0016] FIG. 2A is a view of a coil per turn composed of multiple stages in the prior art as seen from the radial direction of the rotating electrical machine. FIG. 2B is a cross-sectional view taken along line IIB-IIB in FIG. 2A.

[0017] FIG. 3A is a view of a multi-stage coil per turn as seen from the axial direction of a rotating electrical machine in the prior art. FIG. 3B is a cross-sectional view taken along line IIIB-IIIB in FIG. 3A. FIG. 3C is a circuit diagram in the prior art.

[0018] FIG. 4A is a view of the transposition state of a multi-stage coil per turn as seen from the axial direction of a rotating electrical machine in the prior art. FIG. 4B is a cross-sectional view taken along line IVB-IVB in FIG. 4A. FIG. 4C is a circuit diagram of transposition in the prior art.

[0019] Note that, for the sake of convenience of explanation, FIGS. 1A, 2A, 3A, and 4A are drawings in which the slot cross-sections are linearly developed. In FIGS. 1A, 2A, 3A, and 4A, the opening sides (lower part of the figure) of the slots 410 and 420 face the rotor.

[0020] First, the overall configuration of the coil in the prior art will be described with reference to FIGS. 1 to 4. In FIGS. 1A and 1B, the stator core 101 includes an inner-rotor type rotor (not shown) that is rotatably supported in the circumferential direction with a gap on the radially inner circumferential side. The stator core 101 has a plurality of slots in the circumferential direction, and a coil 500 is inserted into the slots. The coil 500 is coated with an insulating film such as an epoxy resin to ensure insulation between the coils. FIG. 1A shows two slots 410 (first slot), 420 (second slot), and one turn of the coil 500 inserted into the slots. The coil 500 is mechanically and electrically connected to adjacent coils at the connection parts W1 and W2 at the axial ends (coil ends).

[0021] When the motor is driven, an alternating current flows through the coil 500. In FIGS. 1A and 1B, as an example, a state where a positive current flows is shown. That is, a current flows through the coil 500 stored in the slot 410 in the positive axial direction, and a current flows through the coil 500 stored in the slot 420 in the negative axial direction. At this time, according to Ampere's law, magnetic flux is generated around the axial direction of the coil 500. Hereinafter, the magnetic flux densities generated in the slots 410 and 420 are denoted as B1 and B2, respectively. Due to the influence of the magnetic resistance distribution of the slot portion, generally, the closer to the slot opening (gap surface), the higher the magnetic flux density, so B1 > B2. However, for simplicity, B1 and B2 are made equal hereinafter.

[0022] When the motor is driven, the current in the coil changes alternately, so the magnetic flux densities B1 and B2 also change alternately. According to the law of electromagnetic induction, an electromotive force E and an eddy current Ie in the coil are generated in a direction to cancel the change in magnetic flux density ΔB per unit time Δt in the conductor, and thereby an alternating current copper loss Pac is generated. The resistance of the path through which the eddy current Ie in the coil flows is generally called the alternating current resistance Rac. The following relationships hold for each physical quantity (~: a symbol representing proportionality).

[0023] E ~ -ΔB / Δt Ie ~ E / Rac Pac ~ Rac × (square of Ie) Therefore, Pac can be expressed as follows.

[0024] Pac ~ (square of ΔB) / (square of Δt) / Rac In applications such as drive motors for automobiles that are mass-produced, as shown in FIGS. 1A and 1B, in many cases, one segment coil is used for one turn of the coil. When rotating at high speed, the drive frequency increases, that is, Δt decreases, so the alternating current copper loss Pac increases.

[0025] As a countermeasure, as shown in FIGS. 2A and 2B, there is known a method of reducing AC copper loss by forming one turn of a coil with multi-stage flat rectangular wires. In FIGS. 2A and 2B, one turn of the coil is composed of two stages, a first segment coil 510 and a second segment coil 520. The first segment coil 510 and the second segment coil 520 are formed with a rectangular cross-section in a substantially U shape and inserted into slots 410 and 420. With such a configuration, the magnetic flux densities B1 and B2 passing through one segment coil become half of the magnetic flux densities shown in FIGS. 1A and 1B, and since the cross-sectional area of one segment coil becomes 1 / 2, the resistance Rac of the path through which the coil eddy current Ie flows becomes twice as large. Therefore, compared with the AC copper loss generated in the coil 500 of FIGS. 1A and 1B, the AC copper losses generated in the first segment coil 510 and the second segment coil 520 are 1 / 8 each, and the total is 1 / 4.

[0026] By configuring with multi-stage flat rectangular wires in this way, the AC copper loss can be significantly reduced. However, in FIGS. 2A and 2B, there are drawbacks that the number of welding points increases by a factor of two at the connection parts W1 and W2 of the coil ends, making the manufacturing complicated, and problems such as insulation film damage and poor welding are likely to occur in the welding process, and ensuring the reliability of the motor becomes an issue.

[0027] As a technique for suppressing the increase in the number of welding points, for example, as shown in FIGS. 3A and 3B, there is a method of welding a plurality of segment coils together. In FIGS. 3A and 3B, the first segment coil 510 and the second segment coil 520 are welded together at the connection parts W1 and W2 of the coil ends, respectively. However, in this configuration, since the first segment coil 510 and the second segment coil 520 are electrically short-circuited, a closed loop as shown in the circuit diagram of FIG. 3C is formed, and there is a problem that new losses are generated due to the flow of the circulating current Ic.

[0028] In FIGS. 3A and 3B, electromotive forces E1t and E1b are respectively generated in the first segment coil 510 and the second segment coil 520 so as to cancel the magnetic flux density B1 of the slot 410. Similarly, electromotive forces E2t and E2b are respectively generated so as to cancel the magnetic flux density B2 of the slot 420. All of these electromotive forces are generated in the same direction. If the sum is E, the circulating current Ic is proportional to E. Therefore, as the driving frequency increases during high-speed rotation, the loss due to the circulating current Ic becomes so large that it cannot be ignored.

[0029] Therefore, as shown in FIGS. 4A and 4B, by transposing the coil arrangement, the generation of the circulating current Ic can be suppressed. As shown in the slot cross-section of FIG. 4A, in the slot 410, the first segment coil 510 and the second segment coil 520 are arranged on the 1t side and the 1b side respectively, while in the slot 420, the arrangement of the first segment coil 510 and the second segment coil 520 is interchanged so that they are on the 2b side and the 2t side respectively. As a result, the electromotive forces E1t and E2b generated in the first segment coil 510 are in opposite directions to each other and are thus canceled out. Similarly, the electromotive forces E1b and E2t generated in the second segment coil 520 are also canceled out. As a result, the generation of the circulating current Ic is suppressed, and the AC copper loss can be reduced without increasing the number of welding points.

[0030] However, in the prior art, additional equipment and additional man-hours are required for transposition, which causes a problem of a significant cost increase. In addition, there is a problem that the axial height of the stator increases for transposition, leading to an increase in the size of the motor.

[0031] As described above, in order to provide a highly efficient and reliable rotating electrical machine, there are problems that cause an increase in cost and size. The present invention solves these problems, and the specific solution means and principle will be described below with reference to FIGS. 5A to 6D.

[0032] FIG. 5A is a view of the transposition state of the coils per turn in the first embodiment of the present invention as seen from the axial direction of the rotating electrical machine. FIG. 5B is a view of the transposition state of the coils per turn in the first embodiment of the present invention as seen from the radial direction of the rotating electrical machine.

[0033] In FIG. 5A, slot 410 is composed of a first layer 411 and a second layer 412, and slot 420 is similarly composed of a first layer 421 and a second layer 422. The first layers 411, 421 and the second layers 412, 422 are arranged side by side from the inner side in the radial direction to the outer side in the radial direction of the rotating electrical machine. That is, the first layers 411, 421 are located on the inner side in the radial direction, and the second layers 412, 422 are located on the outer side in the radial direction with respect to the first layers 411, 421. Note that the first layers 411, 421, 422 and the second layers 412, 422 may be formed by providing a partition in the slots 410, 420 to physically separate them, or may be named according to the position where the coil is arranged without providing a partition in the slots 410, 420.

[0034] The first segment coil 510 straddles in the circumferential direction, one is inserted into the slot 410 (the first slot) and is the slot insertion portion 515a arranged in the first layer 411 of the slot 410, and the other is inserted into the slot 420 (the second slot) and is the slot insertion portion 515b arranged in the second layer 422 of the slot 420, and a transition portion 200 is provided near the center of the circumferential straddle. The transition portion 200 is a region including the apex portion 511a of the portion protruding from the end face of the stator core 101 and is formed to transition in the radial direction of the rotating electrical machine. Further, the transition portion 200 is formed between the transition end portions 511b, 511c of the first segment coil 510.

[0035] The second segment coil 520 spans in the circumferential direction. One side is inserted into the slot 410 (the first slot), and the slot insertion part 525a is arranged radially outside (outer circumferential side) of the first segment coil 510 in the first layer 411 of the slot 410. The other side is inserted into the slot 420 (the second slot), and the slot insertion part 525b is arranged radially inside (inner circumferential side) of the first segment coil 510 in the second layer 422 of the slot 420. Near the center of the circumferential span, it has a transition part 210. The transition part 210 is a region including the apex part 521a of the part protruding from the end face of the stator core 101 and is formed to transition in the radial direction of the rotating electrical machine. Further, the transition part 210 is formed between the transition end parts 521b and 521c of the second segment coil 520.

[0036] The radial transition amounts of the first segment coil 510 and the second segment coil 520 in the transition parts 200 and 210 are x1 and x2 respectively, and they are configured such that x1 > x2. That is, the transition part of the first segment coil 510 is formed to have a larger transition size than the transition part of the second segment coil 520.

[0037] Also, as shown in Fig. 5B, the first segment coil 510 has an inclined part 511, and the inclined part 511 is inclined by an angle θ1 with respect to the end face of the stator core 101. In contrast, the second segment coil 520 has inclined parts 521 and 522. The inclined part 521 (the first inclined part) is inclined at the same angle as the inclined part 511 of the first segment coil 510, while the inclined part 522 (the second inclined part) is inclined at an angle θ2 with respect to the end face of the stator core 101. In this way, a part of the inclined parts of the first segment coil 510 and the second segment coil 520 is configured to be inclined at different angles. That is, the second segment coil 520 is provided with an inclined part 522 inclined at an angle θ2 smaller than the angle θ1 of the inclined part 511 of the first segment coil 510.

[0038] In FIG. 5B, it is configured such that θ1>θ2, and the transition portion 200 of the first segment coil 510 is arranged at a position farther from the end face of the stator core 101 than the transition portion 210 of the second segment coil 520.

[0039] Then, at the transition portions 200 and 210 of the first segment coil 510 and the second segment coil 520, transposition is realized by allowing the second segment coil 520 to pass under the first segment coil 510. In other words, the first segment coil 510 and the second segment coil 520 intersect at their respective transition portions 200 and 210.

[0040] According to the first embodiment, transposition can be achieved by changing the angle θ2 of the inclined portion 522 in the second segment coil 520 and only reducing the axial height without increasing the axial height of the first segment coil 510. Therefore, an increase in the size of the motor can be suppressed. In addition, both the first segment coil 510 and the second segment coil 520 can be manufactured using the same equipment such as bending or sheet metal working. Since the introduction of transposition does not cause an increase in additional equipment or man-hours, an increase in cost can be suppressed.

[0041] The first segment coil 510 and the second segment coil 520 are electrically connected in parallel at at least one location. Regarding the connection method, a configuration in which connection portions W1 and W2 are provided for each turn of the coil as shown in FIG. 4B is common, but a configuration in which one location is provided for every two turns or more turns may also be used, and the effects of this embodiment can be obtained in any configuration. The connection portions W1 and W2 where the first segment coil 510 and the second segment coil 520 are electrically connected are provided on the opposite side in the axial direction with respect to the end face of the stator core 101 provided with the transition portions 200 and 210.

[0042] Also, the transfer parts 200 and 210 and the connection part may be grouped together at the same coil end. However, by configuring the coil end where the transfer parts 200 and 210 are provided and the coil end where the connection part is provided separately, it is possible to improve the manufacturability and simplify the structure.

[0043] Furthermore, when the axial dimension constraint is strict in the transfer parts 200 and 210, the cross-sectional shapes of the first segment coils 510 and the second segment coils 520 in the transfer parts 200 and 210 may be configured to be different from the cross-sectional shapes outside the transfer parts. Specifically, by configuring the first segment coil 510 in the transfer part 200 to have a shorter axial length (thinner in the axial direction), the axial height can be suppressed. The change in the cross-sectional shape of the first segment coil 510 and the second segment coil 520 may be implemented on either the first segment coil 510 or the second segment coil 520, or both. That is, the change in the cross-sectional shape of the first segment coil 510 and the second segment coil 520 may be implemented on at least one of the first segment coil 510 and the second segment coil 520.

[0044] Figs. 6A to 6D show a configuration in which a plurality of transposition structures are arranged. Fig. 6A is a view of the state of transposition of a plurality of arranged coils in the first embodiment of the present invention as seen from the axial direction of the rotating electrical machine. Fig. 6B is a view of the state of transposition of a plurality of arranged coils in the first embodiment of the present invention as seen from the radial direction of the rotating electrical machine. Fig. 6C is a perspective view of the state of transposition of a plurality of arranged coils in the first embodiment of the present invention as seen obliquely. Fig. 6D is an enlarged view of the VID part in Fig. 6B.

[0045] In Figs. 6A to 6C, six sets of coils 500a, 500b, 500c, 500d, 500e, and 500f are arranged in the circumferential direction, and each set of coils is composed of a combination of a first segment coil 510a, 510b, 510c, 510d, 510e, 510f and a second segment coil 520a, 520b, 520c, 520d, 520e, 520f.

[0046] According to this embodiment, even when arranging a plurality of segment coils, transposition can be realized without interference between the segment coils.

[0047] As shown in FIG. 6D, the second segment coil 520f is composed of two inclined portions 521f and 522f with different inclination angles. The spatial distances from other second segment coils 520e adjacent to the second segment coil 520f are different at the inclined portions 521f and 522f, and the respective spatial distances are y1 and y2. When currents are applied to the second segment coils 520f and 520e, particularly when out-of-phase currents are applied, it is necessary to set a spatial distance y2 that has sufficient dielectric strength with respect to the potential difference generated between the two coils. At this time, in FIG. 6D, the axial width of the second segment coil 520f is the same for the inclined portion 521f and the inclined portion 522f, but a predetermined y2 may be ensured by making the width of the inclined portion 522f narrower than that of the inclined portion 521f. Further, a narrow portion may be provided in the same manner for the inclined portions of the adjacent second segment coils 520e.

[0048] In addition, in FIG. 5B, the inclined portions 521 and 522 of the second segment coil 520 are located on the circumferential delay side with respect to the transfer portion 210, but in FIGS. 6A to 6D, they are located on the circumferential advance side. Thus, the arrangement of the inclined portions 521 and 522 may be on the circumferential delay side or the advance side with respect to the transfer portion 210, and in any case, transposition can be realized without interference between the plurality of coils.

Embodiment

[0049] Next, a second embodiment of the present invention will be described with reference to FIG. 7. FIG. 7A is a view of the transposition state of the coils per turn in the second embodiment of the present invention as seen from the radial direction of the rotating electrical machine. FIG. 7B is a modification 1 in the second embodiment of the present invention. FIG. 7C is a modification 2 in the second embodiment of the present invention.

[0050] In the second embodiment, the difference from the first embodiment lies in the difference in the shapes of the first segment coil 510 and the second segment coil 520.

[0051] In FIG. 7A, the first segment coil 510 and the second segment coil 520 each have inclined portions 511 and 521 with different inclination angles. Focusing on the second segment coil 520, in FIG. 5B, since it has two (a plurality of) inclined portions 521 and 522, a bending process is required two times (a plurality of times) during manufacturing. However, in FIG. 7A, since there is one inclined portion 521, the bending process can be shortened.

[0052] Also, according to the second embodiment, transposition is possible by reducing only the axial height of the second segment coil 520 without increasing the axial height of the first segment coil 510, so an increase in the motor size can be suppressed. On the other hand, the point that the angle θ2 of the second segment coil 520 is smaller than the angle θ1 of the first segment coil 510 is the same as in FIG. 5B. As described in FIG. 6D, it is necessary to set a space distance with sufficient dielectric strength between adjacent second segment coils 520.

[0053] Next, similarly in FIG. 7B which is a modification 1 of FIG. 7A, the first segment coil 510 and the second segment coil 520 each have inclined portions 511 and 521 with different inclination angles. The difference from FIG. 7A is that instead of reducing the angle θ2 of the second segment coil 520, the angle θ1 of the first segment coil is increased. In this case, in order to suppress an increase in the axial height of the first segment coil 510, the axial height (position of the apex portion 511a) of the first segment coil 510 is used as a reference, and the axial height (position of the apex portion 521a) of the second segment coil 520 is adjusted to be lower. Further, a curved portion 513 is provided on the circumferential advance side of the first segment coil 510 to make the inclination angles on the circumferential advance sides of the first segment coil 510 and the second segment coil 520 coincide.

[0054] According to Modification Example 1, since the dielectric strength between adjacent second segment coils 520 can be easily ensured, the reliability can be improved.

[0055] Next, in FIG. 7C which is Modification Example 2 of FIG. 7A, the first segment coil 510 has two (a plurality of) inclined portions 511 and 512. The inclined portion 511 is inclined at the same angle θ2 as the inclined portion 521 of the second segment coil 520, while the inclined portion 512 is inclined at an angle θ1 larger than the angle θ2. In FIG. 7C, the difference from FIG. 7B is that the angle θ1 of the first segment coil 510 becomes larger only in the vicinity of the apex portion 511a which is the axial direction of the coil end, and it has the same shape as the second segment coil 520 otherwise. That is, the angle θ1 is made larger from the curved portion 513a located in the vicinity of the apex portion 511a of the first segment coil 510, and further a curved portion 513b is provided on the circumferential advance side of the apex portion 511a, and the inclination angles on the circumferential advance side of the first segment coil 510 and the second segment coil 520 are made to coincide. In this case, in order to suppress an increase in the axial height of the first segment coil 510, the axial height (position of the apex portion 511a) of the first segment coil 510 is used as a reference, and the axial height (position of the apex portion 521a) of the second segment coil 520 is adjusted to be lower.

[0056] According to Modification Example 2, since the dielectric strength between adjacent segment coils can be easily ensured, the reliability can be improved.

Embodiment

[0057] Next, the third embodiment of the present invention will be described with reference to FIGS. 8A and 8B. FIG. 8A is a view of the transposition state of the coils per turn in the third embodiment of the present invention as seen from the axial direction of the rotating electrical machine. FIG. 8B is a view of the transposition state of the coils per turn in the third embodiment of the present invention as seen from the radial direction of the rotating electrical machine.

[0058] In the third embodiment, the difference from the first embodiment is that the shapes of the first segment coil 510 and the second segment coil 520 as viewed in the radial direction are interchanged. That is, the second segment coil 520 has an inclined portion 521, and the inclined portion 521 is inclined by an angle θ2 with respect to the end face of the stator core 101. On the other hand, the first segment coil 510 has inclined portions 511 and 512. The inclined portion 511 (the first inclined portion) is inclined at the same angle as the inclined portion 521 of the second segment coil 520, while the inclined portion 512 (the second inclined portion) is inclined at an angle θ1 with respect to the end face of the stator core 101.

[0059] In FIG. 8B, it is configured such that θ1 < θ2, and the transition portion 210 of the second segment coil 520 is disposed at a position farther from the end face of the stator core 101 than the transition portion 200 of the first segment coil 510.

[0060] Then, at the transition portions 200 and 210 of the first segment coil 510 and the second segment coil 520, transposition is realized by having the first segment coil 510 pass under the second segment coil 520. In other words, the first segment coil 510 and the second segment coil 520 intersect at their respective transition portions 200 and 210.

[0061] According to the third embodiment, transposition can be achieved by changing the angle θ1 of the inclined portion 512 in the first segment coil 510 and reducing only the axial height without increasing the axial height of the second segment coil 520. Therefore, an increase in the size of the motor can be suppressed. In addition, both the first segment coil 510 and the second segment coil 520 can be manufactured using the same equipment such as bending or sheet metal working, and no additional equipment or increase in man-hours is caused due to the introduction of transposition. Therefore, an increase in cost can be suppressed.

Embodiment

[0062] Next, a fourth embodiment of the present invention will be described with reference to FIGS. 9A to 11B. FIGS. 9A and 9B are explanatory views of a method for assembling a coil per turn in the fourth embodiment of the present invention. FIG. 9C is a view of the first and second segment coils in the fourth embodiment of the present invention as seen in the circumferential direction.

[0063] As shown in FIG. 9A, coils 500a and 500b are each divided vertically at the axial center. The upper half is divided into a first segment coil 510a and a second segment coil 520a, and the lower half is similarly divided into a first segment coil 510b and a second segment coil 520b. In other words, the first segment coil 510a and the second segment coil 520a are combined to form coil 500a (the first coil), and the first segment coil 510b and the second segment coil 520b are combined to form coil 500b (the second coil). The divided coils 500a and 500b are provided with connection portions 600 (600a, 600b) that are connected within the slot 400.

[0064] The lower end of the first segment coil 510a is located above the lower end of the second segment coil 520a, and the upper end of the first segment coil 510b is located above the upper end of the second segment coil 520b. As a result, step portions 601a and 601b having an L-shaped step shape with respect to each other are formed at the respective connection portions 600a and 600b of the coils 500a and 500b when viewed from the circumferential direction of the rotating electrical machine. The lower end of the first segment coil 510a and the upper end of the first segment coil 510b face each other in the axial direction of the rotating electrical machine, and the lower end of the second segment coil 520a and the upper end of the second segment coil 520b face each other in the axial direction of the rotating electrical machine and fit within the slot 400. Then, as shown in FIG. 9B, the coils 500a and 500b fit together so as to fill each other's step portions 601a and 601b.

[0065] In addition, the stepped portions 601a and 601b between the coil 500a and the coil 500b are provided with conductive portions 610a, 610b, 620a, and 620b for electrically connecting the coil 500a and the coil 500b. The conductive portions are formed on the respective opposing surfaces of the first segment coil 510a and the second segment coil 520a, and on the respective opposing surfaces of the first segment coil 510b and the second segment coil 520b.

[0066] In the radial direction of the rotating electrical machine, the conductive portion 620a of the second segment coil 520a faces the conductive portion 610a of the first segment coil 510a and also faces the conductive portion 610b of the first segment coil 510b. Further, the conductive portion 610b also faces the conductive portion 620b of the second segment coil 520b. As a result, a state is formed in which the respective conductive portions are in surface contact in the radial direction, ensuring electrical continuity of the originally separate conductors (the first segment coil 510 and the second segment coil 520).

[0067] With this method, welding of the coils for ensuring electrical continuity becomes unnecessary, thus improving the manufacturing workability. Each conductive portion has a simple process of peeling the insulating film of the conductor and performing plating treatment. However, as long as electrical continuity of the connection portion and electrical insulation of other portions can be ensured, it is not limited to this process. Also, by making the film thickness of the conductive plating portion larger than the insulating film thickness, the conductive surfaces can be surely brought into surface contact. Further, after assembling in the state of FIG. 9B, the electrical continuity of the connection portion can be further improved by melting the conductive surfaces by high-frequency induction heating. The electrical continuity of the connection portion can also be further improved by melting the conductive surfaces by resistance welding or the like instead of high-frequency induction heating. In the case of resistance welding, the start end and the end end of the coil are drawn out for each phase, and the operation process can be simplified by applying an impulse current once or a plurality of times. In addition, the start end and the end end may be drawn out for each one turn or a plurality of turns of the coil, and an impulse current may be applied once or a plurality of times.

[0068] Next, the configuration when the connection method shown in FIGS. 9A to 9C is applied to the transposition structure described in the first to third embodiments will be described. FIG. 10A is a view of a multi-stage coil per winding as viewed from the axial direction of the rotating electrical machine in the fourth embodiment of the present invention. FIG. 10B is a cross-sectional view taken along line XB-XB in FIG. 10A. FIG. 10C is a circuit diagram in the fourth embodiment of the present invention.

[0069] As shown in FIG. 10B, at the coil connection portions W1m and W2m in the central portion in the axial direction, the first segment coil 510a and the second segment coil 520a are connected together. With this configuration, since the first segment coil 510a and the second segment coil 520a are electrically short-circuited, a closed loop as shown in the circuit diagram of FIG. 10c is formed, and a circulating current is generated.

[0070] Therefore, as shown in FIG. 10A, in the slot 410 (first slot), the first segment coil 510a and the second segment coil 520a are arranged on the 1t side and the 1b side, respectively, while in the slot 420 (second slot), the first segment coil 510a and the second segment coil 520a are arranged on the 2b side and the 2t side, respectively, by changing the arrangement. As a result, the electromotive forces E1t and E2b generated in the first segment coil 510a are in opposite directions to each other and are canceled, and similarly, the electromotive forces E1b and E2t generated in the second segment coil 520a are also canceled. As a result, the generation of the circulating current Ic is suppressed, the AC copper loss can be reduced, and since welding at the coil end is not required, the manufacturing cost can be reduced.

[0071] When this connection method is adopted, it is preferable to configure as shown in FIGS. 11A and 11B.

[0072] FIG. 11A is a schematic diagram showing the connection state of the coils in the fourth embodiment of the present invention. FIG. 11B is a perspective view showing the connection state of the coils in the fourth embodiment of the present invention.

[0073] As shown in FIGS. 11A and 11B, the coil 500a and the coil 500b are inserted into the slots 400 from both axial sides of the stator core 101, respectively. The coil 500a and the coil 500b are electrically connected within the slot 400 to form a connection portion 600. Further, in the coil 500a and the coil 500b, a transition portion 200a of the first segment coil 510a, a transition portion 210a of the second segment coil 520a, a transition portion 200b of the first segment coil 510b, and a transition portion 210b of the second segment coil 520b are formed, respectively. That is, the transition portions are provided on both axial sides of the rotating electrical machine with respect to the stator core 101.

[0074] According to the fourth embodiment, by inserting the coil 500a having the transition portions 200a and 210a and the coil 500b having the transition portions 200b and 210b from both axial ends of the stator core 101, transposition is possible, and the manufacturing workability of the rotating electrical machine can be improved.

Embodiment

[0075] Next, a fifth embodiment of the present invention will be described with reference to FIG. 12. FIG. 12 is a schematic configuration diagram of a vehicle in the fifth embodiment of the present invention.

[0076] The first to fourth embodiments of the present invention described above are applied to the rotating electrical machines 751 and 752 shown in FIG. 12. The vehicle 700 refers to, for example, a hybrid vehicle or a plug-in hybrid vehicle, and is equipped with an engine 760, rotating electrical machines 751 and 752, and a battery 780.

[0077] When driving the rotating electrical machines 751 and 752, the battery 780 supplies DC power to a power conversion device 770 (inverter device) for driving. The power conversion device 770 converts the DC power from the battery 780 into AC power and supplies this AC power to the rotating electrical machines 751 and 752, respectively.

[0078] During regenerative braking, the rotary electric machines 751 and 752 generate AC power according to the vehicle's kinetic energy and supply it to the power conversion device 770. The power conversion device 770 converts the AC power from the rotary electric machines 751 and 752 into DC power and supplies this DC power to the battery 780. Then, the battery 780 is charged.

[0079] The rotational torque generated by the engine 760 and the rotary electric machines 751 and 752 is transmitted to the wheels 710 via the transmission 740, the differential gear 730, and the axles 720.

[0080] Generally, automobiles are required to have a wide range of driving conditions, such as low-speed high-torque during hill starts, high-speed low-torque on highways, and medium-speed medium-torque during city driving. In such a wide range of driving conditions, the rotary electric machines 751 and 752 can operate with high efficiency. In addition, since heat loss is reduced, the safety and lifespan of the vehicle 700 can be improved. Also, the cruising range of the vehicle 700 can be extended.

[0081] In addition, since the rotary electric machines 751 and 752 need to contribute to the vehicle's weight reduction and ensure passenger space, they are required to be small and lightweight. According to the fifth embodiment, by applying the rotary electric machines described in the first to fourth embodiments to the vehicle, it is possible to provide a vehicle with reduced size and weight.

[0082] Note that in the fifth embodiment, even in an electric vehicle that does not include the engine 760 and is driven only by the power of the rotary electric machines, the same effects can be obtained by applying the rotary electric machines according to the first to fourth embodiments of the present invention.

Explanation of Reference Numerals

[0083] 101…Fixed core, 200, 210…Transfer part, 400…Slot, 410…Slot, 411…First layer, 412…Second layer, 420…Slot, 421…First layer, 422…Second layer, 500, 500a, 500b, 500c, 500d, 500e, 500f…Coil, 510, 510a, 510b, 510c, 510d, 510e, 510f…First segment coil, 511, 512…Inclined part, 511a…Vertex part, 511b, 511c…Transfer end part, 513, 513a, 513b…Curved part, 520, 520a, 520b, 520c, 520d, 520e, 520f…Second segment coil, 521, 522…Inclined part, 521a…Vertex part, 521b, 521c…Transfer end part, 600…Connection part, 610a, 610b, 620a, 620b…Conductive part, 700…Vehicle, 710…Wheel, 720…Axle, 730…Differential gear, 740…Transmission, 751, 752…Rotating electrical machine, 760…Engine, 770…Power conversion device, 780…Battery

Claims

【Claim 1】 comprising a rotor and a stator, wherein the stator includes a stator core having a plurality of slots and segment coils with a rectangular cross-section formed in a substantially U-shape and inserted into the slots, and the rotating electrical machine is the slots are composed of at least a first slot and a second slot, the segment coils are composed of at least a first segment coil and a second segment coil, each of the first slot and the second slot has a first layer and a second layer arranged from the inner side in the radial direction to the outer side in the radial direction of the rotating electrical machine, each of the first segment coil and the second segment coil includes a slot insertion part arranged in the first slot and the second slot, a transition part formed in a region including the apex of a part protruding from the end face of the stator core and configured to transition in the radial direction of the rotating electrical machine, and an inclined part formed between the slot insertion part and the apex and inclined with respect to the end face of the stator core, one of the first segment coils is arranged in the first layer of the first slot, and the other is arranged in the second layer of the second slot, one of the second segment coils is arranged radially outside the first segment coil in the first layer of the first slot, and the other is arranged radially inside the first segment coil in the second layer of the second slot, the transition parts of the first segment coil and the second segment coil are inclined from the first layer to the second layer when viewed axially, and are arranged to intersect at their respective transition parts, the transition part of the first segment coil is formed to have a larger size of transition than the transition part of the second segment coil, the inclined part of the first segment coil and the inclined part of the second segment coil are inclined at different angles with respect to the end face of the stator core, The first segment coil or the second segment coil is configured such that the cross-sectional shape of the transition portion is different from the cross-sectional shape of portions other than the transition portion so that the axial length becomes shorter at the transition portion. The first segment coil and the second segment coil are configured to be divided so as to face each other in the axial direction of the rotating electrical machine, and each of the divided first segment coil and the second segment coil is provided with a connection portion that is connected within the slot. Each of the connection portions is formed with a stepped portion having an L-shaped stepped shape when viewed in the circumferential direction so as to fit with each other. A rotating electrical machine, characterized in that each of the stepped portions where the divided first segment coil and the second segment coil face each other in the radial direction is provided with a conductive portion through which the divided first segment coil and the second segment coil are electrically connected. **Claim 2** In the rotating electrical machine according to claim 1, the first segment coil and the second segment coil are connected in parallel at at least one location. **Claim 3** In the rotating electrical machine according to claim 1, the transition portion is provided on both axial sides of the rotating electrical machine. **Claim 4** In the rotating electrical machine according to any one of claims 1 to 3, the transition portion of the first segment coil is arranged at a position farther from the end face of the stator core than the transition portion of the second segment coil, and at least a part of the inclined portion of the second segment coil is inclined at an angle smaller than the inclined portion of the first segment coil. **Claim 5** In the rotating electrical machine according to any one of claims 1 to 3, the transition portion of the second segment coil is arranged at a position farther from the end face of the stator core than the transition portion of the first segment coil. A rotating electrical machine, wherein at least a part of the inclined portion of the first segment coil is inclined at an angle smaller than that of the inclined portion of the second segment coil. Claim 6 A vehicle comprising: a rotating electrical machine; a battery; and a power conversion device configured to convert DC power of the battery into AC power and supply the AC power to the rotating electrical machine. In a vehicle in which torque of the rotating electrical machine is transmitted to wheels via a transmission. A vehicle, comprising the rotating electrical machine according to any one of claims 1 to 4.

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