Stator for rotating electric machine and rotating electric machine

Abstract

To provide a stator for a rotary electric machine capable of reducing a coil end height, and a rotary electric machine comprising the same.SOLUTION: A stator for a rotary electric machine comprises: an annular stator core comprising a plurality of slots; and a rectangular wire type coil made of a plurality of rectangular wire type segment coils, in which the segment coils pass through the slots and protrude from a core end face. An end of one segment coil and an end of the other segment coil in the rectangular wire type coil form a connection part outside the slots. An angle formed by a thickness direction of the rectangular wire type coil and a normal direction of the core end face at the connection part is 0° or more and less than 90°.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a stator for a rotating electric machine and a rotating electric machine, and more particularly to a stator for a rotating electric machine that can reduce the coil end height and a rotating electric machine including the same. [Background technology]

[0002] Generally, in motors using rectangular wire coils, the straight portions of the segmented coils are inserted into slots in the stator core, the protruding portions of the coils that protrude from the end faces of the stator core are then bent, and the ends of the bent coils are then welded together to form electrical windings.

[0003] A stator with a reduced coil end height has been proposed (see Patent Document 1). In this stator, in order to reduce the coil end height of the stator, the ends of the segment coils that are bent and protrude from the core end face are overlapped and welded together to form a connecting portion. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2019-140819 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the stator of Patent Document 1, at the connecting portion that determines the coil end height, the width direction of the rectangular wire coil is aligned with the normal direction to the core end face, which poses a problem that the coil end height is not reduced sufficiently in automotive rotating electric machines, which require further performance improvement.

[0006] The present invention has been made in consideration of the problems associated with the prior art, and aims to provide a stator for a rotating electric machine that can reduce the coil end height, and a rotating electric machine equipped with the same. [Means for solving the problem]

[0007] As a result of extensive research into achieving the above-mentioned objective, the inventor discovered that the above-mentioned objective can be achieved by setting the angle between the thickness direction of the flat wire segment coil and the normal direction to the core end face at the connection point between the segment coils within a predetermined range, and thus completed the present invention.

[0008] That is, the stator for a rotating electric machine of the present invention comprises an annular stator core having a plurality of slots and a plurality of rectangular wire segment coils, the segment coils passing through the slots and protruding from the core end face. The end of one of the rectangular wire coils forms a connection part outside the slot with the end of another segment coil. At this connection part, the angle between the thickness direction of the rectangular wire coil and the normal direction to the core end face is 0° or more and less than 90°. The flat wire coil has twisted portions formed on both sides of the connecting portion. do.

[0009] Furthermore, a rotating electric machine according to the present invention includes a stator for a rotating electric machine and a rotor for a rotating electric machine, wherein the stator for a rotating electric machine is the stator for a rotating electric machine described above. [Effects of the Invention]

[0010] According to the present invention, the angle between the thickness direction of the flat wire segment coil and the normal direction to the core end face at the connection point between the segment coils is within a predetermined range, thereby making it possible to provide a stator for a rotating electric machine and a rotating electric machine equipped with the same that can reduce the coil end height. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a partial perspective view showing an embodiment of a stator for a rotating electric machine according to the present invention; [Figure 2]2 is a partial plan view showing the stator for the rotating electric machine shown in FIG. 1. [Figure 3] 2 is a partial side view showing the stator for the rotating electric machine shown in FIG. 1. [Figure 4] FIG. 4(A) is a partial perspective view showing a connecting portion in another embodiment of a stator for a rotating electric machine of the present invention, and FIG. 4(B) is a cross-sectional view of the connecting portion shown in FIG. 4(A) taken along line B-B'. [Figure 5] FIG. 5(A) is a partial perspective view showing a connecting portion in yet another embodiment of a stator for a rotating electric machine of the present invention, and FIG. 5(B) is a cross-sectional view of the connecting portion shown in FIG. 5(A) taken along line B-B'. [Figure 6] Figure 6(A) is a partial perspective view showing a connecting portion in yet another embodiment of a stator for a rotating electric machine of the present invention, Figure 6(B) is a plan view showing the end of the connecting portion shown in Figure 6(A), and Figure 6(C) is an explanatory diagram explaining the structure in which the ends of the connecting portion shown in Figure 6(A) are fitted together. [Figure 7] FIG. 2 is a perspective view showing an example of a rectangular wire segment coil. [Figure 8] Figure 8(A) is a front view showing the processed end of the flat wire segment coil shown in Figure 7, Figure 8(B) is an enlarged view of the end surrounded by line B shown in Figure 8(A), and Figure 8(C) is an enlarged view of the end surrounded by line C shown in Figure 8(A). [Figure 9] 9 is a front view showing the state in which the rectangular wire segment coil shown in FIG. 8 is inserted into and passes through a slot. [Figure 10] 9 is a front view showing how the end side of the rectangular wire segment coil shown in FIG. 8 is twisted. [Figure 11] 9 is a front view showing how the end side of the rectangular wire segment coil shown in FIG. 8 is bent. [Figure 12] Figure 12(A) is a front view showing the state in which the ends of the flat wire segment coils shown in Figure 8 are connected to each other, and Figure 12(B) is a plan view showing an enlarged view of the connection portion surrounded by line B shown in Figure 12(A). DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, a stator for a rotating electric machine and a rotating electric machine according to the present invention will be described in detail with reference to the drawings. Note that the dimensional proportions in the drawings cited below are exaggerated for the convenience of explanation and may differ from the actual proportions.

[0013] (First embodiment) As shown in Figures 1 to 3, the stator 2 for a rotating electric machine of this embodiment includes an annular stator core 21 having a plurality of slots 21A and a plurality of rectangular wire coils 23. Although more rectangular wire coils 23 are actually wound around the stator core 21, these are omitted for convenience of explanation. Figures 1 and 2 also show a rotor 3 for a rotating electric machine, and this embodiment also illustrates an embodiment of a rotating electric machine of the present invention. In reality, a rotor shaft, a plurality of magnets, etc. are assembled to the rotor 3, but these are omitted for convenience of explanation.

[0014] The flat wire coil 23 is made up of a plurality of flat wire segment coils 25x, 25y, and the flat wire segment coils 25 are arranged in the stator core 21 so as to pass through the slots 21A and protrude from the core end faces 21B. The end 251x of the flat wire segment coil 25x and the end 251y of the flat wire segment coil 25y are connected outside the slots 21A to form a connecting portion 231.

[0015] In this embodiment, the flat wire coil 23 has twisted portions 233 formed on both sides of the connecting portion 231 and having a constant thickness. The flat wire coil 23 is also arranged in the slot 21A with the thickness direction of the flat wire coil 23 aligned substantially radially of the stator core 21. In the illustrated example, the twisted directions of the twisted portions 233 on both sides are opposite to each other, but they may be the same.

[0016] In the present invention, the angle θ between the thickness direction t of the rectangular wire coil 23 and the normal direction h of the core end face 21B at the connecting portion 231 is configured to be equal to or greater than 0° and less than 90° (see FIG. 1). In the illustrated example, since both the thickness direction of the rectangular wire coil 23 at the connecting portion 231 and the normal direction of the core end face 21B are in the direction indicated by arrow Z, the angle they form is 0° (see FIG. 3).

[0017] Here, the width of the flat wire coil is greater than the thickness, and the width and thickness of the flat wire coil can be set appropriately, and are also affected by the ratio between them, but the angle between the thickness direction of the flat wire coil 23 and the normal direction of the core end surface 21B is preferably 0° or more and 45° or less, more preferably 0° or more and 30° or less, and even more preferably 0° or more and 15° or less.

[0018] Furthermore, this connecting portion 231 is basically structured such that two end portions 251 of the flat wire coil 23, which are aligned in the thickness direction, are butted together, but in the illustrated example, the convex and concave shapes of these two end portions 251 are fitted together.

[0019] Next, the advantages of this embodiment will be described. As described above, according to the stator for a rotating electric machine of this embodiment, the angle θ between the thickness direction t of the rectangular wire coil 23 and the normal direction h of the core end face 21B at the connecting portion 231 is set to be equal to or greater than 0° and less than 90°, so the coil end height can be reduced compared to when θ is 90°. For reference, in Figure 3, the shape of the rectangular wire coil when the width direction of the rectangular wire coil at the connecting portion is aligned with the normal direction of the core end face (θ = 90°) is shown by dotted lines.

[0020] Furthermore, the rectangular wire coil 23 is arranged within the slot 21A with its thickness direction aligned with the radial direction of the stator core 21, and twisted portions 233 are formed on both sides of the connecting portion 231 outside the slot 21A, so that the coil end height can be easily and reliably reduced while maintaining a high coil space factor.

[0021] Furthermore, since the two ends 251 of the rectangular wire coil 23, which are aligned in the thickness direction, are butted together at the connecting portion 231, the amount of coil material used can be reduced compared to a case where the two ends are overlapped at the connecting portion, for example. This allows for lighter coils and lower costs, and also shortens the current path of the coil, thereby reducing copper loss in the motor's power loss.

[0022] Furthermore, in the above-described butt joint structure, if the end portions 251, 251 are respectively formed as a convex shape (e.g., a key shape) and a concave shape (a keyhole shape) to form a fitting structure, positioning and alignment of the end portions when forming the connecting portion 231 becomes even easier. Therefore, when forming the connecting portion 231 by welding or the like, there is no need to use a jig to align and constrain the positions of the two end portions 251 without any gaps, which simplifies the connecting portion formation process. Furthermore, since there is no need to use a jig as described above, there is no risk of the jig coming into contact with the coil surface and damaging it, which improves the quality of the coil insulation performance. Furthermore, since the coil bending accuracy is sufficient as long as the end portions can fit together, the bending accuracy can be relaxed, and the coil bending machine can be simplified. Even when the connecting portion 231 is formed by a high-temperature furnace using methods other than welding, such as soldering, sintering, or nanocrystalline grain bonding, there is no need to use a jig to align and constrain the positions of the end portions 251, 251 without any gaps, and the connecting portion formation process can be performed using simple production equipment.

[0023] Furthermore, the stator for a rotating electric machine as described above can be applied to a rotating electric machine, in which case the axial length of the motor can be shortened, thereby increasing the degree of freedom in installation in an electric vehicle. Furthermore, the miniaturization of the motor can contribute to reducing the weight and cost of the electric vehicle.

[0024] Here, a method for manufacturing a stator for a rotating electrical machine will be described with reference to the drawings, taking the stator for a rotating electrical machine of the first embodiment as an example.

[0025] A U-shaped flat wire segment coil 25 as shown in FIG. 7 is formed using a bending device using a mold. Next, the end 251 of the flat wire segment coil 25 is formed into a convex shape (key shape) (FIG. 8(B)) and a concave shape (keyhole shape) (FIG. 8(C)) as shown in FIG. 8 by shearing or other processing. Next, as shown in FIG. 9, the flat wire segment coil 25 is inserted into a slot (not shown) in the stator core 21. In the illustrated example, only a portion (three pieces) of the flat wire segment coil is shown. Next, as shown in FIG. 10, the base of the flat wire segment coil 25 is held by a pressing jig 100, and the end is held by a rotating jig 101. These jigs are preferably made of resin, which is less likely to scratch the surface of the flat wire segment coil.

[0026] Then, the rotating jig 101 attached to the end is twisted approximately 90° around the center of the cross section of the flat wire segment coil 25 as indicated by the arrow X. Next, as shown in FIG. 11, the base of the flat wire segment coil 25 is restrained by a holding jig 100, and a bending jig 102 is placed on the side of the flat wire segment coil 25 to bend the protruding portions of the multiple flat wire segment coils 25 as indicated by the arrow W. Furthermore, as shown in FIG. 12, this bending process results in the convex and concave shapes of the two ends 251 of the flat wire coil 23, which are aligned in the thickness direction, being fitted together and held together at the connecting portion 231. Thereafter, these ends are joined by laser welding or the like, and the welded portion is coated with an insulating paint to obtain the stator for a rotating electric machine of the first embodiment.

[0027] (Second embodiment) Fig. 4 shows another embodiment of the stator for a rotating electric machine of the present invention. As shown in Fig. 4(A), the stator for a rotating electric machine 4 of this embodiment has the same configuration as the stator for a rotating electric machine shown in Fig. 1, except that the connecting portion 231 has a structure in which two end portions 251 are overlapped and crimped within a cylindrical member 235. In the illustrated example, the angle between the thickness direction of the rectangular wire coil 23 and the normal direction to the core end surface at the connecting portion 231 is 0°. Such a connecting portion 231 can be formed by overlapping and arranging the two end portions 251 within a cylindrical member 235, and then crimping the cylindrical member 235, as shown in Fig. 4(B).

[0028] The stator for a rotating electric machine of this embodiment has the above-described crimping structure. In addition to the advantages of the stator for a rotating electric machine of the first embodiment, the coupling portion can be formed by mechanical joining. This eliminates the need for expensive equipment such as a laser welding device, and the coupling portion formation process can be performed using simple production equipment such as a crimping device. Furthermore, since the coupling portion 231 does not need to be heated to a high temperature during the coupling portion formation process, there is no need to consider the thermal effects on the resin of the coil insulating coating. Therefore, it is no longer necessary to widen the spacing between the coupling portions 231 to account for the thermal effects, as was previously required, and the coil end height can be further reduced. Furthermore, because the coupling portion 231 does not melt, there is no risk of defects such as voids occurring. Furthermore, the coupling state can be controlled by the external shape of the tubular member 235, improving the coupling quality of the coupling portion 231.

[0029] (Third embodiment) FIG. 5 shows a third embodiment of a stator for a rotating electric machine according to the present invention. As shown in FIG. 5, the stator for a rotating electric machine 6 of this embodiment has the same configuration as the stator for a rotating electric machine shown in FIG. 1 , except that, in a connecting portion 231, two end portions 251 are overlapped within a tubular member 235, and the end portions 251 and the tubular member 235 are joined with a bonding material 237. In the illustrated example, the angle between the thickness direction of the rectangular wire coil 23 and the normal direction to the core end surface in the connecting portion 231 is 0°. As shown in FIG. 5(B), such a connecting portion 231 can be formed by overlapping two end portions 251 with bonding materials 237 arranged at predetermined positions within a tubular member 235, and then placing the tubular member in a high-temperature furnace.

[0030] The stator for a rotating electric machine of this embodiment has the above-described holding and joining structure with a cylindrical member, and the end portion 251 is held by the cylindrical member 235. Therefore, in addition to the advantages of the first embodiment, since the end portion 251 of the connecting portion 231 is held by the cylindrical member 235, multiple types of joining can be performed in a single step, such as solder joining, joining with a conductive adhesive, joining with a metal paste, and joining with nanocrystalline particles. Furthermore, since the joining portion, which has low mechanical strength due to solder or conductive adhesive, is reinforced by the cylindrical member 235, the joining strength of the connecting portion 231 is excellent. Furthermore, since there are no shape restrictions on the connecting portion 231, such as the reach of a laser beam in laser welding or the ability to perform crimping, the degree of freedom in the shape of the connecting portion 231 can be increased.

[0031] (Fourth embodiment) FIG. 6 shows a fourth embodiment of a stator for a rotating electric machine according to the present invention. Note that the arrow Y in FIG. 6(C) indicates the normal direction to the core end face (not shown). As shown in FIG. 6, the stator 8 for a rotating electric machine according to this embodiment has the same configuration as the stator for a rotating electric machine shown in FIG. 1, except that, at the connecting portion 231, both end portions 251 of the rectangular wire coil 23 face each other at a certain angle, and the both end portions 251, which have a forked shape, are interlocked. In the illustrated example, the angle between the thickness direction of the rectangular wire coil 23 at the connecting portion 231 and the normal direction to the core end face (not shown) is 15°. In the illustrated example, both end portions 251 have a forked shape, but this is not limiting; only one end may have a forked shape.

[0032] The stator for a rotating electric machine of this embodiment has a structure in which the ends having the above-mentioned split shape are interlocked, and in addition to the advantages of the stator for a rotating electric machine of the first embodiment, it can hold the ends together even in flat wire coils with a high cross-sectional flatness, eliminating the need for a jig to hold the ends together during the joint formation process, such as welding, and simplifying the joint formation process. Furthermore, the split shape can be formed by shearing, which is used in the conventional process of removing the insulation coating from flat wire coils. Therefore, there is an advantage that no additional process is required. [Explanation of symbols]

[0033] 1 Rotating electric machine 2,4,6,8 Stators for rotating electrical machines 21 Stator core 21A Slot 21B Core end face 23 Flat wire coil 231 Connecting part 233 Twisted part 235 Cylindrical member 237 Bonding material 25, 25x, 25y rectangular wire segment coil 251,251x,251y end 3 Rotor for rotating electrical machine 100 holding jig 101 Rotating jig 102 Bending jig

Claims

1. The stator core has an annular shape with a plurality of slots, and a plurality of rectangular wire segment coils, the segment coils passing through the slots and protruding from the core end face. An end of one segment coil of the flat wire coil and an end of another segment coil form a connection portion outside the slot, The angle formed between the thickness direction of the flat wire coil and the normal direction of the core end surface at the connecting portion is equal to or greater than 0° and less than 90°, The flat wire coil has twisted portions formed on both sides of the connecting portion. A stator for a rotating electric machine characterized by:

2. 2. The stator for a rotating electric machine according to claim 1, wherein the flat wire coil is arranged in the slot with the thickness direction of the flat wire coil aligned with the radial direction of the stator core.

3. 3. The stator for a rotating electric machine according to claim 1, wherein the connecting portion has a structure in which the two ends of the rectangular wire coil, which are aligned in the thickness direction, are butted together.

4. 3. The stator for a rotating electric machine according to claim 1, wherein the connecting portion has a structure in which the convex and concave shapes of the two ends of the flat wire coil, which are aligned in the thickness direction, are fitted together.

5. 3. The stator for a rotating electric machine according to claim 1, wherein the connecting portion has a structure in which the two end portions are overlapped and crimped within a cylindrical member.

6. 3. A stator for a rotating electric machine according to claim 1 or 2, characterized in that, at the connecting portion, the two end portions are overlapped within a tubular member, and the ends are joined together and between the tubular member and the end portions with a joining material.

7. 3. The stator for a rotating electric machine according to claim 1, wherein the thickness direction of the flat wire coil is angled at the connecting portion, and the two ends, at least one of which has a forked shape, are interlocked with each other.

8. A rotating electric machine comprising: a stator for a rotating electric machine according to any one of claims 1 to 7; and a rotor for a rotating electric machine.

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