Stator of rotary electric machine

Abstract

To provide a stator of a rotary electric machine capable of reducing a temperature rise of a segment coil.SOLUTION: A stator of a rotary electric machine has a stator core and a stator coil wound around the stator core. The stator coil is composed of a plurality of segment coils constituted by a first segment coil, a second segment coil, and a connection member connecting the first segment coil and the second segment coil. Slot paper with insulation quality is wound around the stator core, and the slot paper has a high-heat conduction part at the position corresponding to the connection member.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a stator for a rotating electrical machine. [Background technology]

[0002] Patent Document 1 discloses a rotating electric machine equipped with a stator having a segment coil in which a first segment coil and a second segment coil are connected by a connecting member. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2020-102980 Summary of the Invention [Problem to be solved by the invention]

[0004] At the connection portion of the segment coil where the first segment coil and the second segment coil are connected by a connecting member, the amount of heat generated increases due to an increase in electrical resistance, which may cause the temperature of the segment coil to rise.

[0005] The present invention has been made in consideration of the above-mentioned problems, and its object is to provide a stator for a rotating electric machine that can reduce the temperature rise of segment coils. [Means for solving the problem]

[0006] In order to solve the above-described problems and achieve the object, a stator of a rotating electrical machine according to the present invention is a stator of a rotating electrical machine having a stator core and a stator coil wound around the stator core, wherein the stator coil is composed of a plurality of segment coils including a first segment coil, a second segment coil, and a connecting member connecting the first segment coil and the second segment coil, and an insulating slot paper is wound around the stator coil, and the slot paper is characterized by having a high heat conduction portion at a position corresponding to the connecting member.

[0007] Thereby, in the stator of the rotating electrical machine according to the present invention, heat generated at the connecting portion where the first segment coil and the second segment coil are connected by the connecting member in the segment coil easily moves to the stator core through the high heat conduction portion of the slot paper, so that the temperature rise of the segment coil can be reduced.

[0008] Further, in the above, the high heat conduction portion may be provided in a band shape in the radial direction of the stator core in the slot paper, and the high heat conduction portion may have higher thermal conductivity than portions other than the high heat conduction portion in the slot paper.

[0009] Thereby, the high heat conduction portion can be positioned according to the axial position of the connecting member of the segment coil.

Effect of the Invention

[0010] The stator of the rotating electrical machine according to the present invention has an effect that the temperature rise of the segment coil can be reduced because heat generated at the connecting portion of the segment coil easily moves to the stator core through the high heat conduction portion of the slot paper.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, an embodiment of the stator of the rotating electrical machine according to the present invention will be described. Note that the present invention is not limited to this embodiment.

[0013] FIG. 1 is a cross-sectional view showing a schematic configuration of the stator 1 according to the embodiment. FIG. 2 is an enlarged cross-sectional view of the stator 1 according to the embodiment.

[0014] The stator 1 is combined with a rotor to form a rotating electrical machine. The rotating electrical machine to which the stator 1 is applied may be used as a motor or a generator. Therefore, the stator 1 of the present embodiment may be applied to, for example, a rotating electrical machine mounted on an electric vehicle, which functions as a motor for generating driving power and also functions as a generator for generating electricity by regenerative torque or the like.

[0015] The stator 1 has a stator core 2 and a stator coil 3 wound around the stator core 2. The stator core 2 is roughly divided into an annular core back 21 and a plurality of teeth 22 protruding radially inward from the inner peripheral surface of the core back 21. A slot 23, which is a space for accommodating the stator coil 3, is formed between the teeth 22 adjacent in the circumferential direction. The stator core 2 is manufactured, for example, by laminating a plurality of electromagnetic steel sheets in the thickness direction.

[0016] The stator coil 3 is wound around the teeth 22 of the stator core 2. The connection mode and winding mode of such a stator coil 3 may be appropriately selected according to the specifications of the rotating electrical machine. Therefore, the stator coil 3 may have a configuration in which the coils of the U-phase, V-phase, and W-phase are star-connected or delta-connected. Further, the stator coil 3 may be wound in a distributed winding or a concentrated winding. In any case, in the present embodiment, the stator coil 3 is composed of a plurality of segment coils. In the stator 1 according to the embodiment, six segment coils are inserted into one slot 23.

[0017] The segment coil is obtained by cutting the stator coil 3 into an easily manageable length. In the present embodiment, the segment coil is composed of a first segment coil 31 and a second segment coil 32.

[0018] FIG. 3 is a diagram showing a segment coil in which the first segment coil 31 and the second segment coil 32 are connected by a connecting pipe 33.

[0019] The first segment coil 31 is formed by coating a conducting wire 311 made of a conductive material (such as copper, etc.) with a coil film 312 made of an insulating material. The conducting wire 311 is a square wire with a substantially rectangular cross-sectional shape. Also, the first segment coil 31 is bent and formed into the same shape as when the stator is completed, that is, the final shape. Specifically, the first segment coil 31 has a substantially U shape having a pair of vertical wire portions accommodated in the slot 23 and a connecting portion connecting the pair of vertical wire portions. The length of the vertical wire portion is substantially the same as the axial dimension of the stator core 2. In this embodiment, the "axial direction" refers to the direction of the axis AX of the stator core 2. When the vertical wire portion of the first segment coil 31 is inserted into the slot 23, the end of the vertical wire portion is positioned near the axial end of the slot 23. The connecting portion extends in the circumferential direction outside the axial direction of the stator core 2 and constitutes a part of the coil end. At both ends of the first segment coil 31, that is, at the ends of the vertical wire portions, there are formed peeling portions where the coil film 312 is peeled off and the conducting wire 311 is exposed to the outside.

[0020] The second segment coil 32 is formed by coating a conducting wire 321 made of a conductive material (such as copper, etc.) with a coil film 322. The conducting wire 321 is a square wire with a substantially rectangular cross-sectional shape. Also, the second segment coil 32 is bent and formed into the same shape as when the stator is completed, that is, the final shape. Specifically, the second segment coil 32 has a substantially U shape having a pair of vertical wire portions accommodated in the slot 23 and a connecting portion connecting the pair of vertical wire portions. The length of the vertical wire portion is substantially the same as the axial dimension of the stator core 2. Therefore, when the vertical wire portion is inserted into the slot 23, the end of the vertical wire portion is positioned near the axial end of the slot 23. The connecting portion extends in the circumferential direction outside the axial direction of the stator core 2 and constitutes a part of the coil end. At both ends of the second segment coil 32, there are formed peeling portions where the coil film 322 is peeled off and the conducting wire 321 is exposed to the outside.

[0021] In addition, in the present embodiment, the lead wires 311 and 321 used for the first segment coil 31 and the second segment coil 32 respectively are angular wires with a substantially rectangular cross-sectional shape, but may be round wires with a circular cross-sectional shape.

[0022] The first segment coil 31 and the second segment coil 32 are connected to each other via a connecting pipe 33 whose ends are hollow connecting members. The connecting pipe 33 has a cylindrical shape with a through hole formed in its axial direction. The connecting pipe 33 is made of a conductive material (such as copper, etc.), and is electrically connected by being fitted with the first segment coil 31 and the second segment coil 32, and functions as a part of the current path of the stator coil 3, that is, as a part of the stator coil 3. The connecting pipe 33 is arranged so that the whole of the connecting pipe 33 is accommodated in the slot 23 of the stator core 2. At this time, as shown in FIG. 3, the positions of the connecting pipes 33 of each of the plurality of segment coils arranged radially in the slot 23 are shifted so as not to be adjacent in the axial direction in order to suppress electrical short circuits between the connecting pipes 33 adjacent in the radial direction.

[0023] When connecting the first segment coil 31 and the second segment coil 32 to each other via the connecting pipe 33, first, outside the slot 23 of the stator core 2, for example, the lead wire 311 of the first segment coil 31 is press-fitted and fitted to one end of the connecting pipe 33. Then, inside the slot 23 of the stator core 2, the lead wire 321 of the second segment coil 32 is press-fitted and fitted to the other end of the connecting pipe 33. Note that outside the slot 23 of the stator core 2, for example, the lead wire 321 of the second segment coil 32 may be press-fitted and fitted to one end of the connecting pipe 33, and then, inside the slot 23 of the stator core 2, the lead wire 311 of the first segment coil 31 may be press-fitted and fitted to the other end of the connecting pipe 33.

[0024] In the stator 1 according to the embodiment, as shown in FIGS. 1 and 2, an insulating slot paper 4 is provided between the outer peripheral surface of the stator coil 3 inserted into the slot 23 provided in the stator core 2 and the inner peripheral surface of the slot 23. The slot paper 4 is wound around the stator coil 3 and is a member for enhancing the insulation between the stator core 2 and the stator coil 3. The slot paper 4 has a high heat conduction part 41 and a normal part 42. The high heat conduction part 41 is a part having higher thermal conductivity than the normal part 42. Examples of the method for making the high heat conduction part 41 of the slot paper 4 have high heat conduction include a method of applying a heat conductive heat dissipation material such as metal powder to the slot paper 4.

[0025] FIG. 4 is a diagram showing the positional relationship between the high heat conduction part 41 of the slot paper 4 and the connecting part 300 of the segment coil in the slot 23. FIG. 5 is a perspective view showing the positional relationship between the high heat conduction part 41 of the slot paper 4 and the connecting part 300 of the segment coil.

[0026] As shown in FIGS. 4 and 5, in the stator 1 according to the embodiment, the high heat conduction part 41 of the slot paper 4 is positioned so as to correspond to (contact) the connecting part 300 (connecting pipe 33) of the segment coil, and the slot paper 4 is wound around the stator coil 3 (six segment coils). As shown in FIG. 5, the slot paper 4 is wound around the stator coil 3 (six segment coils) so that a gap is formed at the inner end in the radial direction, but the slot paper 4 may be wound around the entire circumference of the stator coil 3.

[0027] At the connection part 300 of the segment coils, the amount of heat generation increases compared to the parts other than the connection part 300 of the segment coils. The reason is that in the segment coils, the conductor 311 of the first segment coil 31 and the conductor 321 of the second segment coil 32 come into contact with the connecting pipe 33, so that the electrical resistance at the contact part increases compared to only the conductors 311 and 321. Since the amount of heat generation when an electric current flows is proportional to the resistance value of the substance, an increase in the amount of heat generation (temperature rise) at the connection part 300 of the segment coils, and thus a temperature rise of the entire segment coils (stator coil 3) occurs.

[0028] In this way, when the temperature of the connection part 300 of the segment coils or the entire segment coils (stator coil 3) rises, for example, it may exceed the heat resistance limit of the insulating coatings (coil coatings 312 and 322) applied to the connecting pipe 33, the first segment coil 31, and the second segment coil 32, causing an electrical short circuit. Also, in order to suppress this, it becomes necessary to strengthen the cooling mechanism of the segment coils, for example, a mechanism for flowing cooling oil through the segment coils to cool the segment coils, and adverse effects such as an increase in cost and vehicle weight accompanying the performance improvement of the cooling mechanism occur.

[0029] In order to reduce the temperature rise of the connection part 300 of such segment coils and the entire segment coil (stator coil 3), in the stator 1 according to the embodiment, the high heat conduction part 41 of the slot paper 4 is positioned so as to correspond (contact) to the connection part 300 (connection pipe 33) of the segment coil. Thereby, the connection part 300 of the segment coil with a large heat generation amount and the high heat conduction part 41 of the slot paper 4 come into contact with each other, improving the heat conductivity from the connection part 300 (connection pipe 33) of the segment coil to the stator core 2 through the high heat conduction part 41 of the slot paper 4. Therefore, the heat generated at the connection part 300 of the segment coil easily moves from the high heat conduction part 41 of the slot paper 4 to the stator core 2, and an increase in the heat generation amount within the segment coil can be suppressed. Therefore, the temperature rise of the connection part 300 of the segment coil, and thus the temperature rise of the entire segment coil (stator coil 3), can be reduced. That is, since heat can be released outside the segment coil, the temperature rise of the entire segment coil (stator coil 3) can be reduced as a result.

[0030] Note that the axial position of the connection part 300 (connection pipe 33) in the segment coil may be anywhere within the slot 23, that is, within the range where the slot paper 4 can cover the segment coil. Also, in FIGS. 4 and 5, the high heat conduction part 41 of the slot paper 4 is divided into two parts in the axial direction, but this is because the axial position of the connection part 300 (connection pipe 33) in the segment coil is divided into two parts. That is, for example, even when the axial position of the connection part 300 (connection pipe 33) in the segment coil is three or more or only one place, it can be adapted by making the high heat conduction part 41 of the slot paper 4 three or more or only one place corresponding to the connection part 300 of the segment coil.

[0031] Also, as shown in FIGS. 4 and 5, the high heat conduction portion 41 of the slot paper 4 is provided in a strip shape in the radial direction, and not only the connection portion 300 (connection pipe 33) of the segment coil but also portions other than the connection portion 300 (connection pipe 33) (coil films 312, 322) are located at the location of the same strip-shaped high heat conduction portion 41. On the other hand, the high heat conduction portion 41 of the slot paper 4 may be provided only at the position of the connection portion 300 (connection pipe 33) of the segment coil in the radial direction.

[0032] Also, in the slot paper 4, the axial length of the high heat conduction portion 41 only needs to be at least the same as the axial length of the connection portion 300 (connection pipe 33) of the segment coil. On the other hand, in the slot paper 4, it is preferable that the axial length of the high heat conduction portion 41 is longer than the axial length of the connection portion 300 (connection pipe 33) of the segment coil. This is because the heat generated at the connection portion 300 (connection pipe 33) of the segment coil moves to a certain extent in the axial direction.

[0033] Also, as a method for making the high heat conduction portion 41 of the slot paper 4 highly heat conductive, for example, the configuration of the slot paper 4 may be changed. For example, generally, the slot paper 4 has a plurality of layers folded on top of each other, but the slot paper 4 may be configured by reducing the number of overlapping layers of the portion (high heat conduction portion 41) that contacts the connection portion 300 of the segment coil compared to other portions (normal portion 42).

[0034] Also, for making the high heat conduction portion 41 of the slot paper 4 highly heat conductive, for example, the material composition such as an insulating layer or an adhesive may be changed between the high heat conduction portion 41 and the normal portion 42.

Explanation of Reference Numerals

[0035] 1 Stator 2 Stator Core 3 Stator Coil 4 Slot Paper 21 Core Back 22 Teeth 23 Slot 31 First Segment Coil 32 Second segment coil 33 Connecting pipe 41 High heat conduction part 42 Normal part 300 Connecting part 311, 321 Conductive wire 312, 322 Coil film

Claims

1. A stator of a rotating electrical machine having a stator core and a stator coil wound around the stator core, wherein: The stator coil comprises: a plurality of segment coils composed of a first segment coil, a second segment coil, and a connecting member connecting the first segment coil and the second segment coil; an insulating slot paper is wound around the stator coil; the slot paper has a high heat conduction portion at a position corresponding to the connecting member, characterized in that it is a stator of a rotating electrical machine.

2. The slot paper has the high heat conduction portion provided in a band shape in the radial direction of the stator core; The high heat conduction portion has higher thermal conductivity than portions of the slot paper other than the high heat conduction portion, characterized in that it is the stator of the rotating electrical machine according to Claim 1.

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