Rotating electric machine and method for manufacturing a rotating electric machine

Abstract

To provide a rotating electric machine that can easily prevent contamination caused by the destruction of the foamed layer of insulating paper by refrigerant scattered from the rotor. [Solution] A rotating electric machine comprising a stator in which coils are housed in a plurality of slots via insulating paper, and a rotor rotatably housed in the axial hole of the stator and having a flow path for a refrigerant inside, wherein the stator has coil ends formed by coils protruding from the slots in the axial direction of the stator, and the rotor has a refrigerant outlet, configured such that the refrigerant flowing out from the outlet is scattered toward the coil ends by the rotation of the rotor, wherein the insulating paper has a foamed layer that foams up when heated in the slots to fill the gap between the slots and the coils, the ends of the insulating paper are housed in the slots so as to protrude from the slots in the axial direction of the stator, and a volume reduction section is formed at the ends of the insulating paper in which the foamed bubble portion is destroyed and the volume of the foamed layer is reduced.

Description

Technical Field

[0001] The present disclosure relates to a rotating electric machine and a method for manufacturing a rotating electric machine. Background Art

[0002] A rotating electric machine includes a stator configured by mounting coils in a plurality of slots of a stator core respectively, and a rotor rotatably supported in a shaft hole of the stator. The coils are each inserted into the corresponding slot via insulating paper, and coil ends are formed by portions protruding from the axial end face of the stator. Insulating paper having a foam layer is known in the art. The foam layer is heated and foamed in the slot to fill the gap between the slot and the coil and hold the coil. Both ends of the insulating paper inserted into the slot slightly protrude from the opening of the slot along the axial direction of the stator, in order to prevent contact between the coil and the opening edge of the slot and secure a creepage distance (see, for example, Patent Document 1).

[0003] Further, there is known a rotor having a cooling function that performs cooling by causing a coolant to flow through a flow passage formed inside the rotor. A rotor having a cooling function has an outflow port through which the coolant flows out on an axial end face of the rotor (see, for example, Patent Document 2). Prior Art Documents Patent Documents

[0004] Patent Document 1 International Publication No. 2020 / 067352 Patent Document 2 Japanese Patent No. 6594401 Summary of the Invention Problem to be Solved by the Invention

[0005] When the rotor, which has a cooling function, rotates, the refrigerant flowing out from the outlet is scattered by centrifugal force towards the coil ends of the stator, which are located radially outward. As a result, the coil ends are also cooled by the refrigerant, but the scattered refrigerant collides with the edges of the insulating paper protruding from the slots, causing damage to the foamed layer of the insulating paper. This is because, after foaming, the resin walls separating the foamed beads (resin particles) in the base resin become thinner due to the expansion of the foamed beads. If the scattering pressure of the refrigerant, which collides with the insulating paper at high speed from the rotor, exceeds the material strength of the resin wall, the resin wall is scraped and peeled off by the direct impact of the refrigerant, resulting in undesirable contamination.

[0006] To prevent damage to the foam layer, it is conceivable to redesign the stator or rotor so that refrigerant scattered from the rotor does not collide with the edges of the insulating paper, or to fold the edges of the insulating paper protruding from the slots so that the foam layer is positioned inward, preventing scattered refrigerant from directly colliding with the foam layer. However, this would incur excessive costs for each model of rotating electric machine, and would also require the introduction of new equipment for folding the insulating paper, making neither of these measures particularly economical.

[0007] Therefore, the present disclosure aims to provide a rotating electric machine and a method for manufacturing a rotating electric machine that can easily prevent contamination caused by the destruction of the foamed layer of insulating paper by refrigerant scattered from the rotor. [Means for solving the problem]

[0008] (1) A stator (e.g., stator 2 described later) in which coils (e.g., coil 5 described later) are housed via insulating paper (e.g., insulating paper 4 described later) in a plurality of slots (e.g., slot 23 described later) arranged around a shaft hole (e.g., shaft hole 22 described later), and a rotor (e.g., rotor 3 described later) rotatably housed in the shaft hole of the stator and having a refrigerant flow path (e.g., refrigerant flow path 314 described later) inside, wherein the stator has coil ends (e.g., coil ends 50 described later) formed by the coils protruding from the slots in the axial direction of the stator, and the rotor has a refrigerant outlet (e.g., outlet 314a described later), and the flow A rotating electric machine (for example, rotating electric machine 1 described later) is configured such that the refrigerant flowing out from the outlet is scattered toward the coil end of the stator by the rotation of the rotor, wherein the insulating paper has a foamed layer (for example, foamed layer 42 described later) that foams up by heating in the slot and fills the gap between the slot and the coil, and the ends of the insulating paper (for example, protruding ends 4d described later) are housed in the slots such that they protrude from the slots in the axial direction of the stator, and a volume reduction processing section (for example, volume reduction processing section Fb described later) is formed at the ends of the insulating paper in which the foamed air bubbles are destroyed and the volume of the foamed layer is reduced.

[0009] According to (1) above, the strength of the foam layer at the edge of the insulating paper can be improved simply by forming a volume reduction section in the foam layer corresponding to the edge of the insulating paper. Therefore, contamination caused by the destruction of the foam layer of the insulating paper due to the impact of refrigerant scattered from the rotor can be easily prevented. Since there is no need to change the design of the stator and rotor or to introduce new equipment, it does not lead to increased costs, and the problem of the destruction of the foam layer of the insulating paper due to refrigerant scattered from the rotor can be addressed economically and at low cost.

[0010] (2) In the rotating electric machine described in (1) above, the volume reduction processing unit is used to pressurize the foamed layer.

[0011] According to (2) above, a volume reduction section can be easily formed simply by pressurizing the foamed layer that has been foamed by heating.

[0012] (3) In the rotating electric machine described in (1) or (2) above, the foam layer is arranged on the side of the insulating paper opposite to the side in contact with the coil.

[0013] According to (3) above, the refrigerant scattered from the rotor comes into direct contact with the foamed layer at the edge of the insulating paper, but because the volume reduction treatment improves the strength of the foamed layer at the edge, the destruction of the foamed layer can be effectively prevented.

[0014] (4) In the rotating electric machine described in any of (1) to (3) above, the insulating paper covers the radially inner side of the coil end within the slot (for example, the side 5a of the coil 5 described later).

[0015] According to (4) above, the refrigerant scattered from the rotor strongly impacts the edge of the insulating paper covering the radially inner side of the coil end, but since the volume reduction treatment improves the strength of the foam layer at the edge, the destruction of the foam layer can be effectively prevented.

[0016] (5) A stator (e.g., stator 2 described later) in which coils (e.g., coil 5 described later) are housed via insulating paper (e.g., insulating paper 4 described later) in a plurality of slots (e.g., slot 23 described later) arranged around a shaft hole (e.g., shaft hole 22 described later), and a rotor (e.g., rotor 3 described later) rotatably housed in the shaft hole of the stator and having a refrigerant flow path (e.g., refrigerant flow path 314 described later) inside, wherein the stator has coil ends (e.g., coil ends 50 described later) formed by the coils protruding from the slots in the axial direction of the stator, and the rotor has a refrigerant outlet (e.g., outlet 314a described later), and the refrigerant flowing out from the outlet is configured to be scattered toward the coil ends of the stator by the rotation of the rotor. A method for manufacturing a rotating electric machine (for example, the rotating electric machine 1 described later), wherein the insulating paper has a foamed layer (for example, the foamed layer 42 described later) that foams up when heated, and before inserting the insulating paper into the slot, a volume reduction processing step is made in which a volume reduction processing section (for example, the volume reduction processing section Fb described later) is formed on the end of the insulating paper (for example, the protruding end 4d described later) in which the foamed air bubbles are destroyed and the foamed layer is subjected to volume reduction processing; an insertion step is made in which the insulating paper with the volume reduction processing section formed thereon is inserted into the slot together with the coil such that the end protrudes axially from the slot; and a foaming step is made in which the insulating paper is heated in the slot to heat and foam the foamed layer, and the foamed foamed layer other than the volume reduction processing section fills the gap between the slot and the coil.

[0017] According to (5) above, by simply forming a volume reduction section in the foam layer corresponding to the end of the insulating paper protruding from the slot, foaming during heating within the slot can be suppressed, and the strength of the foam layer at the end can be improved. Therefore, contamination caused by the destruction of the foam layer at the end of the insulating paper due to the impact of refrigerant scattered from the rotor can be easily prevented. Since there is no need to change the design of the stator and rotor or introduce new equipment, it does not lead to increased costs, and the problem of the destruction of the foam layer at the end of the insulating paper due to refrigerant scattered from the rotor can be addressed economically and at low cost.

[0018] (6) In the method for manufacturing a rotating electric machine according to (5) above, in the volume-reduced processed portion forming step, the volume-reduced processed portion is formed by subjecting the end portion of the insulating paper to local heating treatment to cause foaming, and then pressurizing the foamed layer after foaming.

[0019] According to (6) above, the volume-reduced processed portion can be easily formed only by pressurizing the foamed layer that has been foamed by heating.

[0020] (7) In the method for manufacturing a rotating electric machine according to (5) or (6) above, in the inserting step, the insulating paper is inserted into the slot such that the foamed layer is arranged on a surface opposite to a surface in contact with the coil.

[0021] According to (7) above, the refrigerant scattered from the rotor directly collides with the foamed layer at the end portion of the insulating paper, and since the strength of the foamed layer at the end portion is improved by the volume-reduced processed portion, destruction of the foamed layer can be effectively prevented.

[0022] (8) In the method for manufacturing a rotating electric machine according to any one of (5) to (7) above, in the inserting step, the insulating paper is inserted into the slot in a state where the insulating paper covers a radially inner side surface of the coil end (for example, a side surface 5a of a coil 5 described later).

[0023] According to (8) above, the end portion of the insulating paper covering the radially inner side surface of the coil end faces the refrigerant scattered from the rotor, so that the refrigerant directly collides with the end portion, and since the strength of the foamed layer at the end portion is improved by the volume-reduced processed portion, destruction of the foamed layer can be effectively prevented.

Effects of the Invention

[0024] According to the present disclosure, it is possible to provide a rotating electric machine and a method for manufacturing a rotating electric machine that can easily prevent destruction of the foamed layer at the end portion of the insulating paper caused by the refrigerant scattered from the rotor.

Brief Description of Drawings

[0025] [Figure 1] It is an exploded perspective view showing a part of the rotating electrical machine according to the present embodiment. [Figure 2] It is a cross-sectional view showing a rotor of the rotating electrical machine according to the present embodiment. [Figure 3] It is a perspective view showing a coil end of a stator in the rotating electrical machine according to the present embodiment. [Figure 4] It is a plan view schematically showing one slot of a stator in the rotating electrical machine according to the embodiment. [Figure 5] It is a developed view of insulating paper used for the rotating electrical machine according to the present embodiment. [Figure 6] It is a cross-sectional view schematically showing a state of the insulating paper in the slot before foaming. [Figure 7] It is a cross-sectional view schematically showing a state of the insulating paper in the slot after foaming. [Figure 8] It is a diagram for explaining a manufacturing process of insulating paper used for the rotating electrical machine according to the present embodiment. [Figure 9] It is a longitudinal cross-sectional view schematically showing a part of the rotating electrical machine according to the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0026] Hereinafter, the rotating electrical machine of the present disclosure will be described with reference to the drawings. In each of the drawings shown below, corresponding parts are denoted by the same reference signs. Further, with respect to the drawings including directional indications, AD denotes the axial direction of the rotating electrical machine 1, CD denotes the circumferential direction of the rotating electrical machine 1, and RD denotes the radial direction of the rotating electrical machine 1. The respective directions AD, CD, and RD are similarly applied to a stator 2 and a rotor 3 of the rotating electrical machine 1, which will be described later.

[0027] As shown in Fig. 1, the rotating electrical machine 1 is configured to include a stator 2 and a rotor 3. The rotating electrical machine 1 has a casing forming an outer shell, but the casing is omitted from illustration in the rotating electrical machine 1 shown in the present embodiment.

[0028] The stator 2 has a stator core 21. The stator core 21 is formed by stacking multiple annular electromagnetic steel sheets in the axial direction. The stator core 21 has a central axial hole 22 that penetrates through it in the axial direction, and a plurality of slots 23 arranged at equal intervals around the axial hole 22. The slots 23 penetrate the stator core 21 in the axial direction and open at both axial end faces 21a, 21a of the stator core 21. As shown in Figure 3, each slot 23 has a slit 23a that extends along the axial direction of the stator core 21. Each slot 23 opens toward the axial hole 22 through the slit 23a.

[0029] A coil 5 is inserted into each slot 23 via insulating paper 4. In the stator 2 of the rotating electric machine 1 shown in Figure 1, for ease of understanding, coils 5 are schematically shown, with each slot 23 being independent. However, generally, as shown in Figures 3 and 4, multiple coils 5 made of rectangular conductors are inserted into each slot 23 and arranged radially. The ends of each coil 5 inserted into the slot 23 protrude from each slot 23 to both axial end faces 21a, 21a of the stator core 21, forming coil ends 50. The coil ends 50 are positioned on both axial end faces 21a, 21a of the stator core 21, respectively.

[0030] The rotor 3 is composed of a rotor core 31, a rotating shaft 32, and a pair of end plates 33, 33. In the rotor 3 of the rotating electric machine 1 shown in Figure 1, the rotating shaft 32 is omitted from the illustration.

[0031] The rotor core 31 is formed in a cylindrical shape by stacking multiple annular electromagnetic steel sheets in the axial direction. The axial length of the rotor core 31 is approximately equal to the axial length of the axial hole 22 of the stator core 21. The rotor core 31 has an axial hole 311 that penetrates through the center in the axial direction. As shown in Figures 1 and 2, the rotor core 31 has multiple magnet insertion holes 312 that penetrate through the rotor core 31 in the axial direction and are formed at equal intervals along the circumferential direction. A permanent magnet 313 is inserted into each magnet insertion hole 312.

[0032] As shown in Figure 2, multiple refrigerant flow passages 314 are formed inside the rotor core 31, extending along the axial direction of the rotor core 31. The multiple refrigerant flow passages 314 are positioned radially inward from the magnet insertion hole 312 and radially outward from the shaft hole 311, and are arranged at equal intervals in the circumferential direction of the rotor core 31. Both ends of each refrigerant flow passage 314 open to the axial end faces 31a, 31a of the rotor core 31. As a result, refrigerant outlets 314a, 314a are formed at the end faces 31a, 31a of the rotor core 31, respectively.

[0033] The rotating shaft 32 is inserted into the shaft hole 311 of the rotor core 31 and fixed to the rotor core 31 so as not to rotate. As shown in Figure 2, a through hole 321 is formed in the center of the rotating shaft 32, penetrating axially. The through hole 321 constitutes a refrigerant flow path in the rotating shaft 32. The through hole 321 communicates with the refrigerant flow path 314 of the rotor core 31 via a communication hole 315. The refrigerant for cooling the rotor 3 flows in from one axial end of the rotating shaft 32, as indicated by the arrow in Figure 2, flows inside the through hole 321, and flows into the refrigerant flow path 314 of the rotor core 31 through the communication hole 315. The refrigerant that has flowed into the refrigerant flow path 314 cools the rotor core 31 by flowing axially through the rotor core 31, and flows out from the outlets 314a, 314a to the end faces 31a, 31a of the rotor core 31.

[0034] Each of the pair of end plates 33, 33 has a central hole 331, 331 through which the rotating shaft 32 is inserted. The end plates 33, 33 cover each of the end faces 31a, 31a of the rotor core 31, with a small gap S, S between them that allows the coolant to flow.

[0035] The rotor 3 is inserted into the shaft hole 22 of the stator core 21 and is arranged coaxially with a predetermined gap between it and the stator core 21. Both ends of the rotor's rotation axis 32 are rotatably supported by bearings in a casing (not shown). The gaps S,S between the end faces 31a,31a and end plates 33,33 of the rotor core 31 open on the outer circumference of the rotor 3 near the base of the coil ends 50,50 of the stator core 21, i.e., near the boundary between the opening of the slot 23 and the coil ends 50,50. The refrigerant that flows through the refrigerant flow passage 314 of the rotor core 31 and flows out from the outlets 314a,314a flows radially outward through the gaps S,S between the end faces 31a,31a and end plates 33,33 of the rotor core 31 due to the centrifugal force generated by the rotation of the rotor 3, and is scattered toward the base of the coil ends 50,50 of the stator 2. As a result, the coil ends 50,50 are also cooled by the refrigerant.

[0036] As shown in Figure 4, the insulating paper 4 is placed between the inner wall surface 23b of the slot 23 and the coil 5, and is inserted into the slot 23 so as to wrap the entirety of the multiple coils 5 inside the slot 23 along the inner wall surface 23b. As shown in Figure 5, when viewed along the width direction (left-right direction in Figure 5), the insulating paper 4 has a back portion 4a located in the center and a pair of side portions 4b, 4b located on both the left and right sides of the back portion 4a, with each side having the same width.

[0037] As shown in Figure 4, the back portion 4a is positioned to face radially inward and close the slit 23a from inside the slot 23 when inserted into the slot 23. This ensures that the back portion 4a covers the radially inward side of the coil end 50, i.e., the radially inward side 5a of the coil 5 positioned most radially inward within the slot 23. The side portions 4b, 4b are folded radially outward along the boundary with the back portion 4a when inserted into the slot 23, as shown in Figure 4, and extend radially along the inner wall surface 23b of the slot 23. The radially outward ends of the side portions 4b, 4b are folded toward each other, as shown in Figure 4. This ensures that the insulating paper 4 is positioned to wrap around all of the coils 5 within the slot 23.

[0038] Furthermore, as shown in Figure 5, the insulating paper 4 is configured to have a slot housing portion 4c that is housed within the slot 23 when viewed along the axial direction of the stator 2 (up and down direction in Figure 5), and protruding ends 4d, 4d located at both the upper and lower ends of the slot housing portion 4c. The slot housing portion 4c and the protruding ends 4d are formed across the back portion 4a and a pair of side portions 4b, 4b on both sides thereof. In Figure 5, the areas corresponding to the upper and lower protruding ends 4d, 4d are indicated by hatching. The protruding ends 4d, 4d are the parts that protrude from the slot 23 along the extension direction of the coils 5 when the insulating paper 4 is placed in the slot 23 together with a plurality of coils 5. Figure 3 shows the protruding ends 4d of the insulating paper 4 protruding from the slot 23 that opens on one end face 21a of the stator core 21.

[0039] As shown in Figures 6 and 7, the insulating paper 4 has a foamed layer 42 covering the entire surface of one side of a sheet-like base material 41 made of paper or resin, and an adhesive layer 43 covering the entire surface of the other side of the base material 41. The foamed layer 42 is formed, for example, by dispersing foamed beads (resin particles) containing a foaming agent with a heat-expanding function in a base material made of epoxy resin. Generally, as shown in Figure 6, the insulating paper 4 is placed in the slot 23 together with a plurality of coils 5. When the stator core 21 is heated with the insulating paper 4 placed in the slot 23, the foamed layer 42 exhibits its heat-expanding function and foams up, as shown in Figure 7. As a result, the foamed layer 42 expands and fills the gap between the coils 5 and the inner wall surface 23b of the slot 23. When the adhesive layer 43 is positioned in the slot 23 facing the coil 5, the adhesive layer 43 adheres to the multiple coils 5 by heating. When the adhesive layer 43 is positioned in the slot 23 facing the inner wall surface 23b of the slot 23, the adhesive layer 43 adheres to the inner wall surface 23b by heating. In either case, the insulating paper 4 can fix the multiple coils 5 in the slot 23 and hold them to the stator core 21.

[0040] In Figures 6 and 7, the insulating paper 4 is inserted into the slot 23 along with multiple coils 5, with the foam layer 42 facing the inner wall surface 23b of the slot 23 and the adhesive layer 43 facing the coil 5 side. In this case, since the foam layer 42 constitutes the outer surface of the insulating paper 4, the protruding end 4d of the insulating paper 4 shown in Figure 3 has the foam layer 42 exposed to the outside.

[0041] Here, in the insulating paper 4 placed in the slot 23 before heating, the slot housing portion 4c is in an unfoamed state and, when heated, constitutes a foaming function portion Fa that exhibits the normal heat foaming function (see Figure 5). On the other hand, in the insulating paper 4 placed in the slot 23 before heating, the protruding ends 4d, 4d have their heat foaming function suppressed by undergoing a volume reduction treatment on the foamed layer 42 that was pre-foamed before being inserted into the slot 23. When the insulating paper 4 is heated again in the slot 23, it constitutes a volume reduction treatment portion Fb that does not exhibit the heat foaming function, or exhibits the heat foaming function less readily than the foaming function portion Fa.

[0042] The volume reduction section Fb can be formed by applying external physical force to the foamed portion caused by heating, thereby damaging or crushing the foamed air bubbles and reducing their volume. In this embodiment, the volume reduction section Fb is formed by first locally heating the foamed layer 42 to cause foaming before the insulating paper 4 is inserted into the slot 23, and then pressurizing the foamed portion to crush the foamed air bubbles and reduce its volume. Therefore, the thickness of the volume reduction section Fb in the insulating paper 4 after heating (main heating) in the slot 23 is thinner than that of the foamed functional portion Fa. The volume reduction section Fb may be formed over an area slightly larger than the area of ​​the protruding end 4d, to the extent that it does not hinder the fixing function of the coil 5 caused by the foaming of the foamed layer 42 located in the slot housing portion 4c.

[0043] Next, the manufacturing process of the insulating paper 4, which is one step in the manufacturing method of the rotating electric machine 1, will be explained with reference to Figure 8. Figure 8 shows the process before the insulating paper 4 is placed in the slot 23 of the stator core 21 (insulating paper molding) and the process after the insulating paper 4 is placed in the slot 23 of the stator core 21 (assembly).

[0044] First, an insulating paper 4 is formed by creating a foamed layer 42 that exhibits foaming function upon heating across the entire surface of one side of a sheet-like substrate 41, and forming an adhesive layer 43 on the other side (insulating paper forming process). As such an insulating paper 4, a general commercially available product having a foamed layer 42 covering the entire surface of one side may be used.

[0045] Next, the foam layer 42 corresponding to the protruding ends 4d, 4d of the insulating paper 4 is heated locally. This local heating causes the foam beads in the heated foam layer 42 to exhibit a heat-foaming function, forming localized foamed areas 42a in the foam layer 42 (local heating step).

[0046] There are no specific limitations on the method for localized heating. For example, the method may involve heating the insulating paper 4 while masking the area of ​​the slot housing portion 4c where the foamed functional portion Fa should be formed with a heat-insulating mask member; using a selectively heatable heating element and bringing it into contact with the area of ​​the protruding ends 4d, 4d in the foamed layer 42 of the insulating paper 4 where the volume reduction processing portion Fb should be formed, and selectively heating only the contact area; or selectively irradiating the area of ​​the protruding ends 4d, 4d where the volume reduction processing portion Fb should be formed with laser light to heat it. The heating temperature at this time is such that the locally heated portion of the foamed layer 42 exhibits the heat foaming function and begins to foam, but the adhesive layer 43 does not yet exhibit adhesive strength.

[0047] Next, the foamed portion 42a, where the foamed beads have been expanded by the local heating process, is forcibly compressed by applying pressure (local pressurization process). When the foamed portion 42a is forcibly compressed, the bubbles formed by the foaming process are crushed, and the volume of the foamed portion 42a decreases. Consequently, the strength of the resin walls between the foamed beads, which have become thinner due to foaming, increases as the resin walls overlap each other.

[0048] This localized pressurization process forms a volume reduction section Fb in the foamed layer 42 at the protruding ends 4d, 4d, and the non-foamed portion 42b other than the volume reduction section Fb forms a foaming function section Fa in the foamed layer 42. In the volume reduction section Fb, the foam beads in the foamed layer 42 have already foamed, so the foaming function is lost and they will not foam again even if heated, or new foaming will not occur easily. On the other hand, in the foaming function section Fa, the foam beads are not foamed, so they exhibit foaming function and foam when heated.

[0049] Next, the insulating paper 4, in which the volume reduction section Fb has been formed and the foaming function section Fa is in an unfoamed state, is inserted into the slot 23 of the stator core 21 together with a plurality of coils 5 (insertion step). The entire slot housing portion 4c of the insulating paper 4 is placed inside the slot 23. The protruding ends 4d, 4d of the insulating paper 4 protrude from both ends in the axial direction of the slot 23. As shown in Figure 9, here the insulating paper 4 is placed inside the slot 23 such that the side with the foamed layer 42 faces the inner wall surface 23b of the slot 23, and the side with the adhesive layer 43 faces the coils 5.

[0050] Subsequently, the entire insulating paper 4 is heated by heating the stator core 21, causing the foamed layer 42 of the foamed functional section Fa to foam (main heating step). The heating temperature at this time is such that the foamed layer 42 exhibits its normal heat-foaming function and begins to foam, and the adhesive layer 43 exhibits adhesive strength. The foamed functional section Fa, which is the part of the foamed layer 42 other than the volume reduction processing section Fb, is not heated in the local heating step, so it exhibits its normal heat-foaming function and foams when heated in this main heating step. As a result, the foamed functional section Fa of the foamed slot housing section 4c fills the gap between the coil 5 and the inner wall surface 23b of the slot 23, and the adhesive layer 43 exhibits its adhesive function within the slot 23, fixing multiple coils 5 within the slot 23. On the other hand, in this main foaming step, the volume reduction processing section Fb does not foam at all, or foams very little, so as shown in Figure 9, it is formed to be relatively thinner than the foamed functional section Fa that has expanded due to foaming.

[0051] After the stator 2 is formed, the rotor 3 is inserted into the axial hole 22 of the stator 2. The rotation axis 32 of the rotor 3 is rotatably supported by a bearing of a casing (not shown). In the resulting rotating electric machine 1, the protruding end 4d of the insulating paper 4 is positioned radially outward of the end face plate 33 of the rotor 3, as shown in Figure 9. The volume reduction section Fb of the insulating paper 4 is positioned to face the gap S between the axial end face 31a of the rotor core 31 and the end face plate 33 from the radially outward side. In this embodiment, the volume reduction section Fb is formed over a wider area in the axial direction than the area of ​​the protruding end 4d that protrudes from the end face 21a of the stator core 21. Therefore, as shown in Figure 9, the volume reduction section Fb extends to a position slightly recessed into the slot 23 beyond the end face 21a of the stator core 21.

[0052] In such a rotating electric machine 1, as shown by the arrow in Figure 9, the refrigerant flowing out from the outlet 314a of the refrigerant flow passage 314 of the rotor 3 is scattered radially outward toward the coil end 50 by the rotation of the rotor 3 and collides at high speed with the protruding end 4d of the insulating paper 4 through the gap S. However, since a volume reduction section Fb with locally increased strength is formed in the foamed layer 42 corresponding to the protruding end 4d, the foamed layer 42 is less likely to be abraded, and the generation of contamination is suppressed or inhibited. The inventors confirmed that even when a fluid (water) with a scattering pressure of 50 MPa was brought into contact with the volume reduction section Fb of the insulating paper 4 of the rotating electric machine 1 manufactured in this way, the foamed layer 42 was not abraded and no peeling was observed. Since this scattering pressure (50 MPa) is far greater than the 2-6 MPa scattering pressure of refrigerant due to the rotation of a normal rotor 3, it can be seen that the generation of contamination from the insulating paper 4 is effectively suppressed or inhibited when the rotating electric machine 1 is in operation.

[0053] The rotating electric machine 1 according to this embodiment provides the following effects. In other words, the rotating electric machine 1 comprises a stator 2 in which coils 5 are housed via insulating paper 4 in a plurality of slots 23 arranged around a shaft hole 22, and a rotor 3 rotatably housed in the shaft hole 22 of the stator 2 and having a refrigerant flow passage 314 inside, wherein the stator 2 has coil ends 50 formed by coils 5 protruding from the slots 23 in the axial direction of the stator 2, and the rotor 3 has a refrigerant outlet 314a, configured such that the refrigerant flowing out from the outlet 314a is scattered toward the coil ends 50 of the stator 2 by the rotation of the rotor 3, wherein the insulating paper 4 has a foamed layer 42 that foams up when heated in the slots 23 to fill the gap between the slots 23 and the coils 5, and each end (protruding end 4d) of the insulating paper 4 is housed in the slots 23 such that it protrudes from the slots 23 in the axial direction of the stator 2, and a volume reduction treatment Fb is formed at the protruding end 4d of the insulating paper 4, where the foamed air bubbles are destroyed and the foamed layer 42 is volume reduced. According to this method, the strength of the foam layer 42 at the protruding end 4d of the insulating paper 4 can be improved simply by forming a volume reduction section Fb on the foam layer 42 corresponding to the protruding end 4d of the insulating paper 4. Therefore, contamination caused by the destruction of the foam layer 42 at the protruding end 4d of the insulating paper 4 due to the impact of refrigerant scattered from the rotor 3 can be easily prevented. Since there is no need to change the design of the stator 2 and rotor 3 or introduce new equipment, it does not lead to increased costs, and the problem of the destruction of the foam layer 42 of the insulating paper 4 by refrigerant scattered from the rotor 3 can be addressed economically and at low cost.

[0054] In this embodiment, the volume reduction section Fb is formed by pressurizing a foamed layer 42. This allows for the easy formation of the volume reduction section Fb simply by pressurizing a foamed layer 42 that has been foamed by heating.

[0055] In this embodiment, the foam layer 42 is positioned on the side of the insulating paper 4 opposite to the side in contact with the coil 5. As a result, the refrigerant scattered from the rotor 3 comes into direct contact with the foam layer 42 at the protruding end 4d of the insulating paper 4. However, since the strength of the foam layer 42 at the protruding end 4d is improved by the volume reduction processing unit Fb, the destruction of the foam layer 42 can be effectively prevented.

[0056] In this embodiment, the insulating paper 4 covers the radially inner side surface (side surface 5a of the coil 5) of the coil end 50 within the slot 23. As a result, the refrigerant scattered from the rotor 3 strongly impacts the protruding end 4d of the insulating paper 4 that covers the radially inner side surface (side surface 5a of the coil 5) of the coil end 50. However, since the strength of the foamed layer 42 of the protruding end 4d is improved by the volume reduction processing unit Fb, the destruction of the foamed layer 42 can be effectively prevented.

[0057] The manufacturing method for the rotating electric machine 1 according to this embodiment provides the following effects. Specifically, the manufacturing method for the rotating electric machine 1 comprises a stator 2 in which coils 5 are housed in a plurality of slots 23 arranged around a shaft hole 22, each via insulating paper 4, and a rotor 3 rotatably housed in the shaft hole 22 of the stator 2 and having a refrigerant flow passage 314 inside, wherein the stator 2 has coil ends 50 formed by coils 5 protruding from the slots 23 in the axial direction of the stator 2, and the rotor 3 has a refrigerant outlet 314a on its axial end face 31a, and the refrigerant flowing out from the outlet 314a is configured to be scattered toward the coil ends 50 of the stator 2 by the rotation of the rotor 3, wherein the insulating paper 4 is heated Therefore, the method for manufacturing a rotating electric machine 1 comprises: a volume reduction processing step of forming a volume reduction processing section Fb on the end of the insulating paper 4, which has a foamed foam layer 42 that foams up, before inserting the insulating paper 4 into the slot 23, where the foamed air bubbles are destroyed and the foam layer 42 is volume-reduced; an insertion step of inserting the insulating paper 4 with the volume reduction processing section Fb formed thereon into the slot 23 together with the coil 5 so that the end (protruding end 4d) protrudes axially from the slot 23; and a foaming step of heating the insulating paper 4 in the slot 23 to heat and foam the foam layer 42, filling the gap between the slot 23 and the coil 5 with the foamed foam layer 42 other than the volume reduction processing section Fb. According to this, by forming a volume reduction processing section Fb on the foam layer 42 corresponding to the protruding end 4d of the insulating paper 4 that protrudes from the slot 23, the strength of the foam layer 42 at the protruding end 4d can be improved. Therefore, it is possible to easily prevent contamination caused by the destruction of the foam layer 42 at the protruding end 4d of the insulating paper 4 due to the impact of refrigerant scattered from the rotor 3. Since there is no need to redesign the stator 2 and rotor 3 or introduce new equipment, it does not lead to increased costs, and the problem of the foam layer 42 of the insulating paper 4 being damaged by the refrigerant scattered from the rotor 3 can be addressed economically and at low cost.

[0058] In this embodiment, the volume reduction section formation step involves applying localized heat treatment to the protruding end 4d of the insulating paper 4, and then pressurizing the foamed layer 42 that has been foamed, thereby forming the volume reduction section Fb. This allows for the easy formation of the volume reduction section Fb simply by pressurizing the foamed layer 42 that has been foamed by heating.

[0059] In this embodiment, the insertion step involves inserting the insulating paper 4 into the slot so that the foam layer 42 is positioned on the side opposite to the side that contacts the coil 5. As a result, the refrigerant scattered from the rotor 3 comes into direct contact with the foam layer 42 at the protruding end 4d of the insulating paper 4. However, since the strength of the foam layer 42 at the protruding end 4d is improved by the volume reduction processing unit Fb, the destruction of the foam layer 42 can be effectively prevented.

[0060] In this embodiment, the insertion step involves inserting the insulating paper 4 into the slot 23 with the insulating paper 4 covering the radially inner side surface (side surface 5a of the coil 5) of the coil end 50. As a result, the refrigerant scattered from the rotor 3 strongly impacts the protruding end 4d of the insulating paper 4 that covers the radially inner side surface (side surface 5a of the coil 5) of the coil end 50. However, since the strength of the foamed layer 42 of the protruding end 4d is improved by the volume reduction processing unit Fb, the destruction of the foamed layer 42 can be effectively prevented.

[0061] In the above embodiment, the protruding ends 4d, 4d of the insulating paper 4 in the slot 23 are arranged to protrude from both axial end faces 21a, 21a of the stator core 21, respectively. However, the protruding ends 4d of the insulating paper 4 in the slot 23 may protrude only from one of the axial end faces 21a of the stator core 21. In this case, the volume reduction processing section Fb is formed only on the foamed layer 42 of the protruding ends 4d that protrude from the slot 23.

[0062] In the above embodiment, the refrigerant flowing out from the outlet 314a of the refrigerant flow passage 314 formed on the axial end face 31a of the rotor 3 is configured to pass between the end face plate 33 and scatter to the coil end 50. However, the rotor in the present invention is not limited to this configuration, as long as the refrigerant scattered by the rotation of the rotor is scattered to the coil end 50. For example, the rotor may not be provided with an end face plate. Alternatively, instead of an end face plate, a cover with through holes only on the end face may be provided, and the refrigerant scattered by the rotation of the rotor may be scattered to the coil end 50 through these through holes. [Explanation of Symbols]

[0063] 1. Rotating electric machine 2 staters 22 Shaft holes 23 slots 3 rotors 314 Refrigerant flow path 314a Outlet 4. Insulating paper 4d Protruding end (end of insulating paper) 42 Foam layer 5 coils 5a Side (radially inner side of the coil end) 50 coil ends Fb volume reduction processing section

Claims

1. A stator in which coils are housed in multiple slots arranged around the shaft hole, each separated by insulating paper, The stator comprises a rotor rotatably housed in the axial hole of the stator and having a refrigerant flow path inside, The stator has coil ends formed by the coils that protrude from the slots in the axial direction of the stator, The rotor has a refrigerant outlet, and the refrigerant flowing out from the outlet is configured to be scattered toward the coil end of the stator by the rotation of the rotor, in a rotating electric machine, The insulating paper has a foamed layer that foams up upon heating within the slot to fill the gap between the slot and the coil, and each end of the insulating paper is housed within the slot such that it protrudes from the slot in the axial direction of the stator. A rotating electric machine, wherein a volume reduction treatment section is formed at the end of the insulating paper, in which the foamed air bubbles are destroyed and the foamed layer is subjected to a volume reduction treatment.

2. The rotating electric machine according to claim 1, wherein the volume reduction treatment unit is subjected to pressurization treatment of the foamed foam layer.

3. The rotating electric machine according to claim 1 or 2, wherein the foam layer is arranged on the surface of the insulating paper opposite to the surface in contact with the coil.

4. The rotating electric machine according to claim 1 or 2, wherein the insulating paper covers the radially inner side surface of the coil end within the slot.

5. A stator in which coils are housed in multiple slots arranged around the shaft hole, each separated by insulating paper, The stator comprises a rotor rotatably housed in the axial hole of the stator and having a refrigerant flow path inside, The stator has coil ends formed by the coils that protrude from the slots in the axial direction of the stator, A method for manufacturing a rotating electric machine, wherein the rotor has a refrigerant outlet, and the refrigerant flowing out from the outlet is configured to be scattered toward the coil end of the stator by the rotation of the rotor, The insulating paper has a foamed layer that foams up when heated, Before inserting the insulating paper into the slot, a volume reduction processing step is performed to form a volume reduction processing section at the end of the insulating paper, in which the foamed air bubbles are destroyed and the foamed layer is subjected to a volume reduction treatment. Insertion step: Insert the insulating paper on which the volume reduction processing section has been formed into the slot together with the coil such that the end protrudes axially from the slot, A method for manufacturing a rotating electric machine, comprising: a foaming step in which the foamed layer is heated and foamed by heating the insulating paper in the slot, and the foamed layer other than the volume reduction section fills the gap between the slot and the coil.

6. The method for manufacturing a rotating electric machine according to claim 5, wherein the volume reduction section formation step is to form the volume reduction section by applying pressure to the foamed layer after locally heating and foaming the end of the insulating paper.

7. The method for manufacturing a rotating electric machine according to claim 5 or 6, wherein the insertion step involves inserting the insulating paper into the slot such that the foam layer is positioned on the side opposite to the side in contact with the coil.

8. The method for manufacturing a rotating electric machine according to claim 5 or 6, wherein the insertion step involves inserting the insulating paper into the slot while covering the radially inner side surface of the coil end.

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