Stator and stator manufacturing method

Abstract

To provide a technique for improving the reliability of cooling passages provided inside a stator slot.SOLUTION: A stator 4 includes a resin sealing portion 30 in which a coil is housed in a slot 8 and sealed with a cured resin, and a cooling flow path 10 extending linearly in the axial direction in the resin sealing portion 30, and the cooling flow path 10 includes a resin flow path 14 having a cured resin as a flow path wall surface 30a, and a tube 50 provided separately from the cured resin, and at least one end of the tube 50 is connected to the resin flow path 14.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a stator and a method for manufacturing a stator. [Background technology]

[0002] In rotating electric machines such as motors and generators, in order to efficiently cool the stator, a structure has been proposed in which a cooling jacket structure is placed on a cylindrical case that is placed on the outer periphery of the stator, and heat is dissipated from the stator to the case. For example, Patent Document 1 discloses a technology in which, in a rotating electric machine in which a coil wound concentratedly around the teeth of a stator is housed in a slot between the teeth, multiple pipes extending axially are arranged in parallel in the internal space of the slot, and a resin material is filled into the gaps between these pipes and the gaps between the pipes and the coils to form a resin layer that closes the slots that open toward the inner circumference of the stator, and a refrigerant is allowed to flow through the pipes. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 4496710 Summary of the Invention [Problem to be solved by the invention]

[0004] However, when damage such as cracks occurs in the cooling flow passage, the cooling medium such as water leaks, and therefore a technology to further improve reliability is required. The technology disclosed in Patent Document 1 is insufficient to solve such a problem, and a new technology is required.

[0005] The present invention has been made in consideration of the above circumstances, and has an object to provide a technique for improving the reliability of a cooling flow passage provided inside a slot of a stator. [Means for solving the problem]

[0006] According to the present invention, the following techniques are provided. (1) A stator having a resin sealing portion in which a coil is accommodated in a slot and sealed with a resin cured material, and a cooling flow passage extending linearly in an axial direction in the resin sealing portion, the cooling flow passage includes a resin flow passage having a flow passage wall surface formed of the cured resin material, and a tube provided separately from the cured resin material, At least one end of the tube is connected to the resin flow path. (2) The stator according to (1), wherein both ends of the tube are connected to the resin flow path. (3) The difference between the linear expansion coefficient of the tube and the linear expansion coefficient of the cured resin of the resin flow path is 2×10 -5 / °C or less. (4) The stator according to any one of (1) to (3), wherein a difference between a thermal conductivity of the tube and a thermal conductivity of the cured resin of the resin flow path is 30 W / (m·K) or less. (5) The stator according to any one of (1) to (4), wherein the tube is a ceramic tube. (6) The stator according to any one of (1) to (4), wherein the tube is a glass tube. (7) The stator according to any one of (1) to (4), wherein the tube is a resin tube made of a thermosetting resin. (8) The stator according to (7), wherein the resin material of the resin tube is the same as the resin material of the resin sealing portion. (9) The stator according to any one of (1) to (8), wherein the length of the tube is 50% or more and 98% or less of the axial length of the slot. (10) The stator according to any one of (1) to (8), wherein a plurality of the tubes are provided in one flow passage provided in one slot. (11) A method for manufacturing a stator comprising the steps of: placing a stator core in a mold; sealing coils in slots with a resin material; and having cooling channels extending linearly in an axial direction within the slots, the method comprising the steps of: a flow path pin preparation step of preparing a flow path pin to which a tube constituting a part of the cooling flow path is attached; a pin arrangement step of arranging the flow path pin to which the tube is attached inside the slot of the stator such that the tube is at a predetermined position within the slot; a resin molding process for filling a resin molding material in a region between the coil and the tube inside the slot so as to fill the periphery of the tube; a pin removal step of removing the flow path pin; A method for manufacturing a stator comprising the steps of: (12) The method for manufacturing a stator described in (11), wherein the pin positioning process positions the tube attached to the flow path pin so that at least one end of the tube is covered with the resin molding material in the resin molding process as the predetermined position for positioning the tube. (13) The method for manufacturing a stator according to claim 11, wherein the pin positioning step positions the tube attached to the flow path pin so that the tube is covered with the resin molding material as the predetermined position for positioning the tube. (14) The difference between the linear expansion coefficient of the tube and the linear expansion coefficient of the cured resin of the resin flow path is 2×10 -5 The method for producing a stator according to any one of (11) to (13), wherein the temperature is 0.1 to 1.5° C. / ° C. or less. (15) The method for manufacturing a stator according to any one of (11) to (14), wherein a difference between the thermal conductivity of the tube and the thermal conductivity of the cured resin of the resin flow path is 30 W / (m·K) or less. (16) The method for producing a stator according to any one of (11) to (14), wherein the tube is a ceramic tube. (17) The method for producing a stator according to any one of (11) to (14), wherein the tube is a glass tube. (18) The method for manufacturing a stator according to any one of (11) to (14), wherein the tube is a resin tube made of a thermosetting resin. (19) The method for manufacturing a stator according to (18), wherein the resin material of the resin tube is the same as the resin molding material. (20) The method for manufacturing a stator according to any one of (11) to (19), wherein the length of the tube is 50% or more and 98% or less of the axial length of the slot. (twenty one) The method for manufacturing a stator according to any one of (11) to (20), wherein a plurality of the tubes are provided in one flow passage provided in one slot. Effect of the Invention

[0007] According to the present invention, it is possible to provide a technique for improving the reliability of a cooling passage provided inside a slot of a stator. [Brief description of the drawings]

[0008] [Figure 1] 1 is a vertical cross-sectional view of a motor according to an embodiment of the present invention taken along a direction perpendicular to a rotation axis of the motor; [Diagram 2] 1 is a vertical cross-sectional view of a motor in a direction of a rotation axis according to an embodiment of the present invention. [Diagram 3] FIG. 4 is an enlarged view of the periphery of a slot according to the embodiment. [Figure 4] FIG. 4 is a cross-sectional view showing a cooling passage within a slot according to an embodiment. [Diagram 5] 11A to 11C are cross-sectional views showing variations of cooling channels inside a slot according to an embodiment. [Figure 6] 6A to 6C are diagrams illustrating a flow path pin preparation step in the manufacturing method of the stator according to the embodiment. [Figure 7] 5A to 5C are diagrams illustrating a pin arrangement step in the manufacturing method of the stator according to the embodiment. [Figure 8] 5A to 5C are diagrams illustrating a resin molding step in the manufacturing method of the stator according to the embodiment. [Figure 9] 5A to 5C are diagrams illustrating a pin removal step in the manufacturing method of the stator according to the embodiment. [Figure 10] 4A to 4C are diagrams showing examples of tube arrangements (structures A, B, and C) of a cooling flow passage according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] <Summary> In this embodiment, an example will be described in which the present invention is applied to an electric motor (motor) as a rotating electric machine (electric motor, generator, or dual-purpose motor / generator). FIG. 1 is a vertical cross-sectional view in a direction perpendicular to the rotational axis direction of motor 100. FIG. 2 is a vertical cross-sectional view in the rotational axis direction of motor 100. FIG. 3 is an enlarged view of the periphery of slot 8 in FIG. 1. FIG. 4 is a cross-sectional view showing cooling water passage 10 in slot 8, taken along the line A1-A1 in FIG. 3.

[0010] <Basic structure of motor 100> The motor 100 includes a case 1, and a rotor 2, a stator 4, and a coil 9 housed inside the case 1. The case 1 includes a cylindrical portion 1a and side plate portions 1b and 1c that close both axial ends of the cylindrical portion 1a. The case 1 can be made of a material such as an aluminum alloy (cast metal casting), a resin material, or a combination thereof.

[0011] <Rotor 2> As shown in Fig. 1, the rotor 2 is housed inside the case 1. At the center of the rotor 2, a rotating shaft 3 is attached as an output shaft, as shown in Fig. 2. Both ends of the rotating shaft 3 are supported by bearings 3a embedded in the side plate portions 1b and 1c. This allows the rotor 2 to freely rotate around the rotating shaft 3.

[0012] Permanent magnets 5 are installed inside the rotor 2. Specifically, as shown in Fig. 1, a plurality of (eight here) permanent magnets 5 are arranged at equal intervals on the same circumference. At this time, the magnetic poles of adjacent permanent magnets 5 are set to be different from each other.

[0013] <Stator 4> As shown in Fig. 2, a cylindrical stator 4 is disposed and fixed on the inner peripheral side of the cylindrical portion 1a so as to surround the outer periphery of the rotor 2. A minute gap (air gap) is provided between the inner peripheral surface 6a of the stator 4 and the outer peripheral surface 2a of the rotor 2. The stator 4 has a stator core 41 and coils 9 disposed in the slots 8 and sealed by a resin sealing portion 30. The resin sealing portion 30 is provided with a cooling water passage 10.

[0014] <Stator core 41> The stator core 41 is provided by stacking a plurality of electromagnetic steel sheets in the axial direction and closely fixing them together, and when viewed from the axial end as shown in Figs. 1 and 3, the stator core 41 is provided with a yoke portion 6 provided in an annular shape and a plurality of teeth portions 7 extending from the yoke portion 6 toward the rotor 2 side (inner circumference side). The plurality of teeth portions 7 are arranged at equal intervals in the circumferential direction. Here, as shown in Fig. 1, 24 teeth portions 7 are provided. The regions between the teeth portions 7 become slots 8, and are sealed by a resin sealing portion 30 in which a coil 9 is placed. In each slot 8, a cooling water passage 10 extending in the axial direction is provided on the center side (rotor 2 side) of the coil 9.

[0015] <Coil 9> The coil 9 is a rectangular wire that is wound so as to straddle the teeth portion 7 and be housed in two spaced apart slots 8. Here, the coil 9 is housed sealed in a resin sealing portion 30 that seals the slot 8 (FIG. 1). The coil 9 is completed by welding the ends (coil ends) of the segment-shaped coil. In this embodiment, the ends of the coil 9 are sealed in the resin sealing portion 30, but if the refrigerant is oil, the ends of the coil 9 do not necessarily have to be sealed.

[0016] <Teeth part 7> The teeth 7 are provided to correspond to the permanent magnets 5 of the rotor 2 described above, and by sequentially exciting each coil 9, the rotor 2 rotates due to attraction and repulsion between the corresponding permanent magnets 5.

[0017] The teeth 7 are tapered so that the circumferential width is large on the outer periphery and small on the inner periphery. Teeth tips 71 are formed at the inner periphery end of the teeth 7, facing each other in the circumferential direction so as to reduce the width of the slot 8.

[0018] <Slot 8> The slots 8 are spaces between adjacent teeth 7, and are provided such that wall surfaces 72 of the teeth 7 facing each other in the radial direction are parallel to each other, as shown in Fig. 3. The space between the tips 71 of the teeth forms an opening on the inner circumferential side of the slots 8.

[0019] As shown in Figure 3, the slot 8 is provided with a plurality of coils 9 arranged radially when viewed from above, a cooling water passage 10, and a resin sealing portion 30 filled in the space except for the coils 9 and the cooling water passage 10.

[0020] <Cooling channel 10> A cooling flow passage 10 extending in the axial direction is provided in the internal space of the slot 8 on the inner circumference 6a side of the stator 4 (i.e., the rotor 2 side) and adjacent to the coil 9. A coolant, for example, cooling water, circulates through the cooling flow passage 10. The inner diameter (flow passage diameter) of the cooling water passage 10 depends on the slot 8 and the required cooling capacity, but can be, for example, 1 mm to 10 mm, preferably 2 mm to 8 mm, and more preferably 3 mm to 6 mm.

[0021] The cooling channel 10 is composed of an area (hereinafter referred to as a "resin channel 14") in which at least a part of the resin sealing portion 30 serves as a channel wall surface 30a in the slot 8, and a tube 50 separate from the resin sealing portion 30. That is, in the slot 8, the resin channel 14 and the tube 50 are connected to form one channel (cooling channel 10). In this embodiment, as shown in FIG. 4, the cooling channel 10 has the tube 50 in the center in the vertical direction as shown, the first resin channel 15 above the tube 50 as shown, and the second resin channel 16 below the tube 50 as shown. That is, the cooling channel 10 is in a state in which the first resin channel 15, the tube 50, and the second resin channel 16 are connected in series in this order from the top side as shown. An upper end 53 of the tube 50 is connected to the first resin channel 15, and a lower end 54 of the tube 50 is connected to the second resin channel 16. In this embodiment, the portion (coil end) of the coil 9 protruding from the slot 8 is sealed with resin 30, and therefore extends to the outside of the slot 8.

[0022] The number of cooling channels 10 arranged in one slot 8 may be one or more, but in a situation where the spatial width of the slot 8 is narrow, it is preferable to have a small number of channels so that the cross-sectional area of ​​the channel is large, taking into consideration the flow resistance when the coolant passes through. The cross-sectional shape of the cooling channel 10 can be circular as in this embodiment, or it can be square or matched to the shape of the slot 8.

[0023] In this embodiment, the coil 9 is a distributed winding wound across a plurality of slots 8. Therefore, at least one cooling passage 10 may be provided for each set of slots 8 constituting one distributed winding. For example, when a coil 9 is wound across two slots 8, one slot 8 is provided with a cooling passage 10, and the other slot 8 is not provided with a cooling passage 10. If at least one slot 8 in a set of multiple slots 8 constituting one distributed winding is provided with a cooling passage 10, the other slots 8 (i.e., teeth 7) not provided with a cooling passage 10 can also be cooled via the coil 9.

[0024] <Resin flow path 14> The resin flow path 14 is provided by using a part of the resin sealing portion 30 as a flow path wall surface 30a. Although details will be described later in the explanation of the manufacturing method, when the resin sealing portion 30 is molded in the slot 8, the outer circumferential surface of the flow path pin 80 is provided so as to correspond to the flow path wall surface 30a.

[0025] <Tube 50> The tube 50 is a cylindrical member with a hollow center in cross section, and various materials can be used for the tube 50. The inner wall surface 51 of the tube 50 serves as a flow path wall surface, and is connected to the flow path wall surface of the resin flow path 14 as a continuous surface. The tube 50 may be a ceramic tube (ceramic tube), a glass tube (glass tube), or a tube made of a hardened thermosetting resin (resin tube).

[0026] When the tube 50 is a ceramic tube, alumina or silicon nitride is preferable as the main material from the viewpoint of thermal conductivity. The thermal conductivity of the ceramic tube is 2 to 30 W / (m K). The linear expansion coefficient of the ceramic tube is 3×10 -6 ~3×10 -6 / ℃. In addition, assuming that the thermal conductivity of the resin material of the resin sealing portion 30 is 0.8 to 5 W, mullite, zirconia, etc. can achieve a thermal conductivity equivalent to or higher than that, and a wide range of materials can be used as the ceramic material, not limited to alumina and silicon nitride. In addition, since the thickness of the ceramic tube can be thinned, the effect of the difference in thermal conductivity is less likely to be observed when a thin ceramic tube is used. As ceramic tubes that are relatively easy to obtain, for example, ceramic tubes manufactured by Haldenwanger and ceramic tubes manufactured by Andermann Ceramics can be used.

[0027] When the tube 50 is a glass tube (glass pipe), although it is somewhat fragile, the member is stable in terms of corrosion resistance and the like. The thermal conductivity of the glass tube is 1 to 3 W / (m K). The linear expansion coefficient of the glass tube is 1×10 -6 ~5×10 -6 / ℃. Glass tubes that are relatively easy to obtain include, for example, glass tubes manufactured by Haldenwanger, quartz tubes manufactured by Andermann Ceramics, and heat-resistant glass tubes manufactured by Annaka Special Glass.

[0028] When the tube 50 is a resin tube, for example, a resin material exemplified as the resin sealing portion 30 described later can be used. The resin material may be the same as that of the resin sealing portion 30, or a different resin material. From the viewpoint of heat resistance, a thermosetting resin is preferable. Regardless of the material, a member previously molded into a tube shape (or pipe shape) is separately prepared and used as the tube 50. The thermal conductivity of the resin tube is 0.2 to 10 W / (m K). The linear expansion coefficient of the resin tube is 5 x 10 -6 ~50×10 -6 / ℃. The glass transition temperature Tg of the resin tube is 150° C. or higher.

[0029] The length of the tube 50 is 50% or more of the axial length of the slot 8. The upper limit of the length is a realistic range of 98% or less, since at least one end of the tube 50 is connected to the resin flow path 14.

[0030] With reference to FIG. 5, variations in the arrangement of the tubes 50 will be described. 5(a) shows that the tube 50 is not in the center of the cooling water passage 10 but is shifted downward as shown in the figure, and the lower end 54 of the tube 50 is located just at the lower boundary of the slot 8 and is exposed without being covered by the resin sealing portion 30 (resin flow passage 14). In this example, the cooling water passage 10 has a first resin flow passage 15 and a tube 50 connected in series from the top.

[0031] 5(b) shows a configuration in which a plurality of tubes 50 (two, a first tube 50a and a second tube 50b) are provided in the cooling water passage 10. In this example, the cooling water passage 10 has a first resin flow passage 15, a first tube 50a, a third resin flow passage 17, a second tube 50b, and a second resin flow passage 16 connected in series in order from the top in the figure within one flow passage in the slot 8.

[0032] <Resin sealing part 30> 3, the resin sealing portion 30 is provided on the inner periphery side (tooth tip 71 side) of the slot 8. The resin sealing portion 30 is provided by insert molding. The resin material used for the resin sealing portion 30 is a thermosetting resin (sealing resin composition) described next.

[0033] In this embodiment, the resin sealing portion 30 seals the coil 9 and the tube 50 in the slot 8. As described above, the resin sealing portion 30 forms the flow path wall surface 30a of the resin flow path .

[0034] 4, the resin sealing portion 30 is filled only inside the slot 8. However, the present invention is not limited to this, and the coil ends 92 of the coils 9 protruding from the slots 8 may also be sealed. In addition, when the cooling water passages 10 extend to the area protruding from the slots 8, the resin sealing portion 30 may be provided to form a resin flow path 14 in the area outside the slots 8.

[0035] (Thermosetting resin composition)

[0036] Hereinafter, the components used in the thermosetting resin composition of the present embodiment (sometimes referred to simply as "resin composition" in this specification) will be described.

[0037] (Epoxy resin) Examples of the epoxy resin used in the thermosetting resin composition of the present embodiment include bifunctional or crystalline epoxy resins such as biphenyl type epoxy resins, bisphenol A type epoxy resins, bisphenol F type epoxy resins, stilbene type epoxy resins, and hydroquinone type epoxy resins; novolac type epoxy resins such as cresol novolac type epoxy resins, phenol novolac type epoxy resins, and naphthol novolac type epoxy resins; phenol aralkyl type epoxy resins such as phenylene skeleton-containing phenol aralkyl type epoxy resins, biphenylene skeleton-containing phenol aralkyl type epoxy resins, and phenylene skeleton-containing naphthol aralkyl type epoxy resins; trifunctional type epoxy resins such as triphenol methane type epoxy resins and alkyl-modified triphenol methane type epoxy resins; modified phenol type epoxy resins such as dicyclopentadiene-modified phenol type epoxy resins and terpene-modified phenol type epoxy resins; heterocyclic type epoxy resins such as triazine nucleus-containing epoxy resins, etc. These may be used alone or in combination of two or more. From the viewpoints of ensuring the fluidity of the resulting resin composition and the strength of a cured product of the resin composition, the epoxy resin preferably contains one or more epoxy resins selected from the group consisting of phenol novolac type epoxy resins and phenol aralkyl type epoxy resins, and more preferably contains a cresol novolac type epoxy resin.

[0038] The content of the epoxy resin in the resin composition may be, for example, 3 mass% or more, preferably 8 mass% or more, more preferably 10 mass% or more, and even more preferably 12 mass% or more, based on the total solid content of the resin composition, from the viewpoint of improving the fluidity of the obtained resin composition and improving the workability and moldability. In addition, from the viewpoint of improving the strength and heat resistance of a cured product formed using the resin composition, the content of the epoxy resin is preferably 30 mass % or less, and more preferably 20 mass % or less, based on the total solid content of the resin composition.

[0039] In this embodiment, the total solid content of the resin composition refers to the non-volatile content in the resin composition, and refers to the remainder excluding volatile components such as water, solvent, etc. In addition, in this embodiment, the content relative to the total amount of the resin composition refers to the content relative to the total solid content of the resin composition excluding the solvent, when a solvent is included.

[0040] In one embodiment, the resin composition may further contain a thermosetting resin other than the epoxy resin. Examples of the thermosetting resin that can be used include bismaleimide resin, benzoxazine resin, phenol resin, urea resin, melamine resin, unsaturated polyester resin, polyurethane resin, diallyl phthalate resin, silicone resin, cyanate resin, polyimide resin, polyamideimide resin, and benzocyclobutene resin. These thermosetting resins may be used alone or in combination of two or more.

[0041] (hardening agent) The curing agent used in the thermosetting resin composition of the present embodiment is not limited as long as it is generally used in resin compositions containing epoxy resins, and examples thereof include phenolic resin-based curing agents, amine-based curing agents, acid anhydride-based curing agents, mercaptan-based curing agents, and other curing agents. Among these, phenolic resin-based curing agents are preferred in terms of the balance of flame resistance, moisture resistance, electrical properties, curability, storage stability, and the like.

[0042] The phenolic resin-based curing agent may be, for example, any one generally used in epoxy resin compositions. More specifically, the phenolic resin-based curing agent may be a novolac resin obtained by condensing or co-condensing phenols such as phenol novolac resin, cresol novolac resin, cresol, resorcin, catechol, bisphenol A, bisphenol F, phenylphenol, aminophenol, α-naphthol, β-naphthol, dihydroxynaphthalene, and the like with formaldehyde or ketones under an acid catalyst; a phenol aralkyl resin having a phenylene skeleton synthesized from the above-mentioned phenols and dimethoxyparaxylene or bis(methoxymethyl)biphenyl; a phenol aralkyl resin such as a phenol aralkyl resin having a biphenylene skeleton; and a phenolic resin having a trisphenylmethane skeleton. These may be used alone or in combination of two or more. The phenolic resin-based curing agent preferably includes a phenol novolac resin.

[0043] When the curing agent is a phenolic resin-based curing agent, the equivalent ratio between the epoxy resin and the curing agent, i.e., the ratio of (the number of moles of epoxy groups in the epoxy resin / the number of moles of phenolic hydroxyl groups in the phenolic resin-based curing agent) is preferably 0.5 or more, more preferably 0.6 or more, and even more preferably 0.8 or more, from the viewpoint of improving the moldability and reliability of the resin composition. Also, from the same viewpoint, the above ratio is preferably 2 or less, more preferably 1.8 or less, and even more preferably 1.5 or less.

[0044] Examples of amine-based curing agents include aliphatic polyamines such as diethylenetriamine (DETA), triethylenetetramine (TETA), and metaxylylenediamine (MXDA); aromatic polyamines such as diaminodiphenylmethane (DDM), m-phenylenediamine (MPDA), and diaminodiphenylsulfone (DDS); and polyamine compounds such as dicyandiamide (DICY) and organic acid dihydralazide. These may be used alone or in combination of two or more.

[0045] Examples of the acid anhydride curing agent include alicyclic acid anhydrides such as hexahydrophthalic anhydride (HHPA), methyltetrahydrophthalic anhydride (MTHPA), and maleic anhydride; and aromatic acid anhydrides such as trimellitic anhydride (TMA), pyromellitic anhydride (PMDA), benzophenonetetracarboxylic acid (BTDA), and phthalic anhydride. These may be used alone or in combination of two or more.

[0046] Examples of mercaptan-based curing agents include trimethylolpropane tris(3-mercaptobutyrate) and trimethylolethane tris(3-mercaptobutyrate). These may be used alone or in combination of two or more.

[0047] Examples of other curing agents include isocyanate compounds such as isocyanate prepolymers and blocked isocyanates; and organic acids such as carboxylic acid-containing polyester resins. The curing agent may be a combination of two or more different types of curing agents from the above.

[0048] From the viewpoint of realizing excellent fluidity and improving filling properties and moldability in the encapsulation process, the content of the curing agent in the resin composition is preferably 0.5 mass % or more, more preferably 1 mass % or more, and even more preferably 3 mass % or more, based on the total amount of the resin composition.

[0049] On the other hand, from the viewpoint of improving the moisture resistance reliability and heat resistance of the cured resin product, the content of the curing agent is preferably 20 mass % or less, more preferably 15 mass % or less, even more preferably 10 mass % or less, and even more preferably 5 mass % or less, based on the total amount of the resin composition.

[0050] (Inorganic filler) Examples of inorganic fillers include fused silica such as fused crushed silica and fused spherical silica, silica such as crystalline silica, alumina, aluminum hydroxide, silicon nitride, and aluminum nitride. These may be used alone or in combination of two or more. From the viewpoint of making the mechanical properties or thermal properties of the cured product of the resin composition favorable, the inorganic filler preferably contains silica, and more preferably contains one or more selected from the group consisting of crushed silica and fused spherical silica.

[0051] The content of the inorganic filler in the resin composition is preferably 50% by mass or more, more preferably 65% ​​by mass or more, and even more preferably 80% by mass or more, based on the total amount of the resin composition, from the viewpoint of suppressing the moisture absorption and thermal expansion of the resin composition and more effectively improving the temperature cycle resistance and moisture resistance of the cured product of the resin composition. In addition, from the viewpoint of more effectively improving the flowability and filling property during molding of the resin composition, the content of the inorganic filler is preferably 95% by mass or less, more preferably 93% by mass or less, based on the total amount of the resin composition.

[0052] In addition, when the inorganic filler contains silica, the content of silica in the resin composition is preferably 50 mass % or more, more preferably 65 mass % or more, and even more preferably 80 mass % or more, based on the total amount of the resin composition, from the viewpoint of suppressing the moisture absorption and thermal expansion of the resin composition and more effectively improving the temperature cycle resistance and moisture resistance of the cured product of the resin composition. From the viewpoint of more effectively improving the fluidity and filling property of the resin composition during molding, the content of silica in the resin composition is preferably 95% by mass or less, and more preferably 93% by mass or less.

[0053] (Other Ingredients) In the present embodiment, the resin composition may further include components other than the above-mentioned components. For example, the resin composition may further include a curing accelerator, a coupling agent, a flame retardant, an ion scavenger, a colorant, and an antioxidant.

[0054] (Cure accelerator) The curing accelerator may be any accelerator that accelerates the crosslinking reaction between the epoxy resin and the curing agent, and any accelerator that is generally used in epoxy resin compositions may be used. Specific examples of curing accelerators include diazabicycloalkenes and derivatives thereof such as 1,8-diazabicyclo(5,4,0)undecene-7; organic phosphines such as triphenylphosphine and methyldiphenylphosphine; imidazole compounds (imidazole curing accelerators) such as 2-methylimidazole; and tetra-substituted phosphonium and tetra-substituted borates such as tetraphenylphosphonium and tetraphenylborate.

[0055] Examples of the imidazole-based curing accelerator include imidazole, 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-phenylimidazole, 1-benzyl-2-methylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazolium trimellitate, 1-cyanoethyl-2-phenyl Examples of such compounds include imidazolium trimellitate, 2,4-diamino-6-[2'-methylimidazolyl(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-undecylimidazolyl(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-ethyl-4-methylimidazolyl(1')]-ethyl-s-triazine, an isocyanuric acid adduct of 2,4-diamino-6-[2'-methylimidazolyl(1')]-ethyl-s-triazine, an isocyanuric acid adduct of 2-phenylimidazole, an isocyanuric acid adduct of 2-methylimidazole, 2-phenyl-4,5-dihydroxydimethylimidazole, and 2-phenyl-4-methyl-5-hydroxymethylimidazole.

[0056] (Coupling Agent) As the coupling agent, for example, various silane-based compounds such as epoxysilane, mercaptosilane, aminosilane, alkylsilane, ureidosilane, vinylsilane, methacrylsilane, titanium-based compounds, aluminum chelates, aluminum / zirconium-based compounds, and other known coupling agents can be used. Examples of these include vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris(β-methoxyethoxy)silane, γ-methacryloxypropyltrimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-methacryloxypropylmethyldiethoxysilane, γ-methacryloxypropyltriethoxysilane, vinyltriacetoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-anilinopropyltrimethoxysilane, γ-anilinopropylmethyldimethoxysilane, γ-[bis(β-hydroxyethyl)]aminopropyltriethoxysilane, N-β-(aminoethyl)-γ-aminopropyl N-(vinylbenzylaminoethyl)-γ-aminopropyltrimethoxysilane, N-(vinylbenzylaminoethyl)-γ-aminopropyltriethoxysilane, N-(vinylbenzylaminoethyl)-γ-aminopropylmethyldimethoxysilane, phenylaminopropyltrimethoxysilane, γ-(β-aminoethyl)aminopropyldimethoxymethylsilane, N-(trimethoxysilylpropyl)ethylenediamine, N-(dimethoxymethylsilylisopropyl)ethylenediamine, methyltrimethoxysilane, dimethyldimethoxysilane, methyltriethoxysilane, N-(vinylbenzylaminoethyl)-γ-aminopropyltrimethoxysilane, γ-chloropropyltrimethoxysilane, hexamethyldisilane, vinyltrimethoxysilane, γ-mercaptopropylmethyldimethoxysilane, 3-isocyanatopropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-triethoxysilyl-N-(1,Silane coupling agents such as hydrolyzate of 3-dimethyl-butylidene)propylamine, isopropyl triisostearoyl titanate, isopropyl tris(dioctyl pyrophosphate) titanate, isopropyl tri(N-aminoethyl-aminoethyl) titanate, tetraoctyl bis(ditridecyl phosphite) titanate, tetra(2,2-diallyloxymethyl-1-butyl)bis(ditridecyl)phosphite titanate, bis(dioctyl pyrophosphate)oxyacetate titanate Examples of titanate-based coupling agents include ethylene titanate, bis(dioctyl pyrophosphate) titanate, isopropyl trioctanoyl titanate, isopropyl dimethacryl isostearoyl titanate, isopropyl tridodecylbenzenesulfonyl titanate, isopropyl isostearoyl diacryl titanate, isopropyl tri(dioctyl phosphate) titanate, isopropyl tricumyl phenyl titanate, and tetraisopropyl bis(dioctyl phosphite) titanate. These may be used alone or in combination of two or more. Among these, silane-based compounds such as epoxy silane, mercapto silane, amino silane, alkyl silane, ureido silane, or vinyl silane are more preferred. In addition, from the viewpoint of more effectively improving filling properties and moldability, it is even more preferred to use secondary amino silanes such as phenyl aminopropyl trimethoxy silane.

[0057] When a coupling agent is used, the content is preferably 0.05% by mass or more, more preferably 0.10% by mass or more, based on the total solid content of the resin composition, from the viewpoint of making the flowability of the resin composition favorable. Also, from the viewpoint of improving the mechanical strength of the cured product of the resin composition, the content of the coupling agent is preferably 1.5% by mass or less, more preferably 1.0% by mass or less, and even more preferably 0.5% by mass or less, based on the total solid content of the resin composition.

[0058] (Coloring agent) Examples of the colorant include carbon black, red iron oxide, titanium oxide, etc. Among them, carbon black is preferably used as the colorant. The content of the colorant is preferably 0.05% by mass or more, more preferably 0.10% by mass or more, based on the total amount of the resin composition, from the viewpoint of obtaining a preferable appearance of the cured product of the resin composition. Also, from the viewpoint of obtaining a preferable resin viscosity, the content of the colorant is preferably 1.5% by mass or less, more preferably 1.0% by mass or less, and even more preferably 0.5% by mass or less, based on the total amount of the resin composition.

[0059] (Antioxidants) Examples of the antioxidant include hindered phenol compounds, hindered amine compounds, and thioether compounds.

[0060] (Characteristics of the thermosetting resin composition or its cured product)

[0061] The thermal conductivity K1 of the cured product of the thermosetting resin composition is 0.5 to 10 W / m·K. The lower limit of the thermal conductivity K1 is preferably 1 W / m·K or more, and more preferably 2 W / m·K or more. The upper limit of the thermal conductivity K1 is not particularly limited, but a realistic value is 10 W / m·K. By setting the thermal conductivity K1 in the above range, the heat of the coil 9 can be effectively transferred to the stator core 41 and the refrigerant (i.e., the cooling water) in the cooling water passage 10.

[0062] The linear expansion coefficient of the cured thermosetting resin composition is 1×10 -6 ~20×10 -6 / ℃. By setting the linear expansion coefficient within the above range, it is possible to reduce the difference with the linear expansion coefficient of the coil 9 and the tube 50, and to suppress the occurrence of cracks and the like at the interfaces with the coil 9 and the tube 50. If cracks and the like occur, there is a concern that the thermal conductivity between them may decrease or deterioration may be accelerated.

[0063] The glass transition temperature Tg1 of the cured product of the thermosetting resin composition is 150° C. or higher. By setting the glass transition temperature Tg1 in the above range, the heat resistance of the motor 100 can be improved, and high output can be achieved.

[0064] <Relationship between the linear expansion coefficient of the tube 50 and the resin sealing portion 30> The difference between the linear expansion coefficient of the tube 50 and the linear expansion coefficient of the cured resin of the resin flow path 14 (i.e., the resin sealed portion 30) is 2×10 -5 / °C or less. The difference is preferably 1×10 -5 / °C or less, and more preferably 0.5×10 -5 / °C or less. If there is a large difference in the linear expansion coefficient between the tube 50 and the resin sealing portion 30, cracks or the like may occur at the interface between the tube 50 and the resin sealing portion 30, and the thermal conduction between the tube 50 and the resin sealing portion 30 may decrease. In particular, if cracks occur at the boundaries between the both ends 53, 54 of the tube 50 and the resin flow path 14, cooling water may penetrate around the tube 50, accelerating deterioration. Therefore, by setting the difference in linear expansion coefficient within the above range, it is possible to suppress such a decrease in thermal conduction and deterioration.

[0065] <Relationship between Thermal Conductivity of Tube 50 and Resin Sealing Portion 30> The difference in thermal conductivity between the tube 50 and the cured resin of the resin flow path 14 (i.e., the resin sealed portion 30) is 30 W / (m·K) or less. If the difference in thermal conductivity between the tube 50 and the resin sealed portion 30 becomes large, a difference will appear in the temperature distribution within the slot 8, and there is a risk of a decrease in the cooling efficiency when viewed overall.

[0066] <Method of manufacturing the stator 40> 6 to 9, a method for manufacturing the stator 40 will be described with a focus on the manufacture of the cooling water passages 10. The manufacturing method is a method for manufacturing a stator 4 in which a stator core 41 is placed in a mold, coils 9 are sealed in slots 8 with a resin material, and the stator 4 has cooling channels 10 extending linearly in the axial direction in the slots 8, and includes a pin placement process S20 for placing channel pins 80 with tubes 50 attached thereto inside the slots 8 of the stator 4 so that the tubes 50 are at predetermined positions in the slots 8, a resin molding process S30 for filling a resin molding material inside the slots 8 in a region between the coils 9 and the tubes 50 so as to fill the periphery of the tubes 50, and a pin removal process S40 for removing the channel pins 80. Each process will be specifically described below.

[0067] Flow path pin preparation process S10: FIG. 6 is a diagram for explaining the flow path pin preparation step S10. The stator core 41 is placed in the mold, and a flow path pin 80 to which a tube 50 constituting a part of the cooling flow path 10 is attached is prepared. The flow path pin 80 has a cylindrical pin body 81 and a pin header 82 provided at one end thereof. The pin body 81 is a cylindrical member whose outer shape is the inner diameter (flow path diameter) of the cooling water path 10, and has a length equal to or greater than the axial depth of the slot 8 (i.e., the thickness of the stator core 41). The tube 50 is attached to a predetermined position of the pin body 81. The position at which the tube 50 is attached is determined by the position at which the tube 50 is provided in the cooling water path 10. In addition, when multiple tubes 50 (first tube 50a, second tube 50b) are provided as shown in FIG. 5(b), multiple tubes 50 are attached to the pin body 81. At this time, the pin body 81 and the tube 50 are not fixed, and the tube 50 can move smoothly through the pin body 81.

[0068] Pin placement process S20: 7 is a diagram illustrating the pin arrangement step S20. The flow path pin 80 to which the tube 50 prepared in the flow path pin preparation step S10 is attached is arranged inside the slot 8 of the stator 4 so that the tube 50 is at a predetermined position within the slot 8. In a step before or after arranging the tube 50 attached to the flow path pin 80 in the slot 8, the coil 9 is arranged in the slot 8.

[0069] Resin molding process S30: 8 is a diagram illustrating the resin molding step S30. After the coil 9 and the tube 50 are placed in the slot 8, a resin molding material is filled into the area between the coil 9 and the tube 50 in the slot 8 so as to fill the periphery of the tube 50.

[0070] Pin removal process S40: FIG. 8 is a diagram for explaining the pin removal step S40. After the resin molding material is filled in the slot 8 and the resin molding material is cured, the flow path pin 80 is removed from the slot 8 (resin sealing portion 30). Here, if the cooling water passage 10 does not have the tube 50 and is entirely the resin flow path 14, the resin flow path 14 and the pin body 81 are in close contact with each other, so the force required for removal is large. In addition, the resin flow path 14 may be dragged by the pin body 81 and deformed. However, in this embodiment, just before the flow path pin 80 is removed, the resin flow path 14 and the pin body 81 are in close contact with each other, but the tube 50 is in a state where the pin body 81 can move smoothly. When the flow path pin 80 (pin body 81) is removed from the slot 8 (resin sealing portion 30), the force required for removal can be reduced by the amount of the tube 50. From another perspective, the speed at which the flow path pin 80 is removed can be increased.

[0071] <Summary of features and functions of Motor 100 (rotating electric machine)> The features of this embodiment are summarized as follows. (1) A stator (4) having a resin sealing portion (30) in which a coil (9) is housed in a slot (8) and sealed with a resin cured material, and a cooling flow passage (10) extending linearly in an axial direction in the resin sealing portion (30), The cooling flow passage 10 includes a resin flow passage 14 having a flow passage wall surface made of the cured resin material, and a tube 50 provided separately from the cured resin material. At least one end of the tube 50 is connected to the resin flow path 14 . (2) The stator 4 according to (1), wherein both ends of the tube 50 are connected to the resin flow path 14. (3) The difference between the linear expansion coefficient of the tube 50 and the linear expansion coefficient of the cured resin of the resin flow path 14 is 2×10 -5 / °C or less. (4) The stator 4 according to any one of (1) to (3), wherein the difference between the thermal conductivity of the tube 50 and the thermal conductivity of the cured resin of the resin flow path 14 is 30 W / (m·K) or less. (5) The stator 4 according to any one of (1) to (4), wherein the tube 50 is a ceramic tube. (6) The stator 4 according to any one of (1) to (4), wherein the tube 50 is a glass tube. (7) The stator 4 according to any one of (1) to (4), wherein the tube 50 is a resin tube made of a thermosetting resin. (8) The stator (4) according to (7), wherein the resin material of the resin tube (50) is the same as the resin material of the resin sealing portion (30). (9) The stator 4 according to any one of (1) to (8), wherein the length of the tube 50 is 50% or more and 98% or less of the axial length of the slot 8. (10) The stator 4 according to any one of (1) to (8), wherein a plurality of the tubes 50 are provided in one flow passage (cooling water passage 10) provided in one slot 8. (11) A method for manufacturing a stator (4) comprising the steps of: placing a stator core (41) in a mold; sealing coils (9) in slots (8) with a resin material; and having cooling channels (10) extending linearly in an axial direction in the slots (8), a flow path pin preparation step S10 for preparing a flow path pin 80 to which a tube 50 constituting a part of the cooling flow path 10 is attached; a pin arrangement process S20 of arranging the flow passage pin 80 to which the tube 50 is attached inside the slot 8 of the stator 4 so that the tube 50 is at a predetermined position within the slot 8; a resin molding process S30 for filling a resin molding material in a region between the coil 9 and the tube 50 inside the slot 8 so as to fill the periphery of the tube 50; a pin removal step S40 of removing the flow path pin 80; A method for manufacturing a stator 4 having the above structure. (12) The method for manufacturing a stator 4 described in (11), wherein the pin arrangement process S20 arranges the tube 50 attached to the flow path pin 80 so that at least one end of the tube 50 is covered with the resin molding material in the resin molding process S30 as the predetermined position for arranging the tube 50. (13) The method for manufacturing a stator 4 described in (11), wherein the pin placement process S20 places the tube 50 attached to the flow path pin 80 in a position where the tube 50 is covered with the resin molding material as the predetermined position for placing the tube 50. (14) The difference between the linear expansion coefficient of the tube 50 and the linear expansion coefficient of the cured resin of the resin flow path 14 is 2×10 -5 The method for producing a stator 4 according to any one of (11) to (13), wherein the temperature is 0.1 to 1.5° C. / ° C. or lower. (15) The method for manufacturing a stator 4 according to any one of (11) to (14), wherein the difference between the thermal conductivity of the tube 50 and the thermal conductivity of the cured resin of the resin flow path 14 is 30 W / (m·K) or less. (16) The method for producing a stator 4 according to any one of (11) to (14), wherein the tube 50 is a ceramic tube. (17) The method for producing a stator 4 according to any one of (11) to (14), wherein the tube 50 is a glass tube. (18) The method for manufacturing a stator 4 according to any one of (11) to (14), wherein the tube 50 is a resin tube made of a thermosetting resin. (19) The method for manufacturing the stator 4 according to (18), wherein the resin material of the resin tube is the same as the resin molding material (the resin material of the resin sealing portion 30). (20) The method for manufacturing a stator (4) according to any one of (11) to (19), wherein the length of the tube (50) is 50% or more and 98% or less of the axial length of the slot (8). (twenty one) The method for manufacturing a stator 4 according to any one of (11) to (20), wherein a plurality of the tubes 50 are provided in one flow passage provided in one slot 8.

[0072] Although the embodiments of the present invention have been described above, these are merely examples of the present invention, and various configurations other than those described above can also be adopted. EXAMPLES

[0073] EXAMPLES Hereinafter, the present invention will be described with reference to examples and comparative examples, but the present invention is not limited to these.

[0074] In this example, structures A, B, and C shown in Figures 10(a) to 10(c) were prepared for the arrangement of the tubes 50 in the cooling flow passage 10, and experiments were performed on the resin filling property in the slot, the water passage pin pull-out force (index value), and the cooling flow passage airtightness in the slot. In the comparative example, a configuration in which no tubes were arranged was used.

[0075] Table 1 shows the ingredients (resin compositions) of the resin-sealed portion 30 used in Examples 1 to 6 and Comparative Example 1. Table 2 shows the physical properties of the resin compositions and tubes in Examples 1 to 6 and Comparative Example 1, and the evaluation results.

[0076] (Preparation of Resin Composition) First, the raw materials formulated according to Table 1 were mixed at room temperature using a mixer, and then roll-kneaded at 70° C. to 110° C. Next, the resulting kneaded product was cooled and then pulverized to obtain a resin composition. Resin material A was used for the resin-sealed portions of Examples 1-3 and Comparative Example 1, and for the tube of Example 3. Resin material B was used for Examples 4-6.

[0077] (Method of manufacturing the cooling channel) The resin filling into the slots and the formation of the cooling channels were performed by preparing a test stator core (axial length 150 mm) and following the manufacturing method of stator 40 described with reference to Figures 6 to 9. Coils were actually placed in the slots and the resin filling was performed. The inner diameter of the channel and the outer diameter of the channel pin were 2.0 mm.

[0078] (tube) The tubes prepared were made of the following materials: Example 1: Ceramic tube (alumina) Inner diameter 2.0 mm, outer diameter 3.0 mm Example 2: Glass tube, inner diameter 2.0 mm, outer diameter 3.0 mm Example 3: Resin tube (resin material A) Inner diameter 2.0 mm, outer diameter 3.0 mm Examples 4 to 6: Ceramic tube (alumina) Inner diameter 2.0 mm, outer diameter 3.0 mm

[0079] (Physical properties) As physical property values ​​of the examples and comparative examples, the thermal conductivity, difference in thermal conductivity, linear expansion coefficient, and difference in linear expansion coefficient of the resin composition and the tube were calculated.

[0080] (Evaluation: Resin filling in slots) The filling of the resin material into the slot (the gap between the coil and the tube) was confirmed. It was confirmed that the filling was good (represented as "A" in Table 2) in all of Examples 1 to 6 and the Comparative Example.

[0081] (Evaluation: Waterway pin pull-out force (index value)) Regarding the channel pin pull-out force, the pull-out force of the comparative example was used as an index (value: F) to measure the pull-out force of Examples 1 to 6. It was confirmed that the pull-out force decreased in all of Examples 1 to 6.

[0082] (Evaluation: Airtightness of cooling passage inside slot) Airtightness was checked as a reliability of the cooling flow path. In the comparative example, some of the multiple water paths had air leakage, and there was room for improvement in terms of manufacturing stability (represented as "B" in Table 2). In Examples 1 to 6, it was confirmed that airtightness was ensured.

[0083] [Table 1] [Table 2] [Explanation of symbols]

[0084] 1 case 2 Rotors 3 Rotation Axis 4 Bearings 5. Permanent magnets 6 Stator 7 Teeth 8 Slots 9 Coil 10 Cooling Channel 14 Resin flow path 15 First resin flow path 16 Second resin flow path 17 Third resin flow path 50 tubes 50a 1st tube 50b 2nd tube 80 Channel Pin 81 pin body 100 Motor

Claims

1. A stator having a resin sealing portion in which a coil is accommodated in a slot and sealed with a resin cured material, and a cooling flow passage extending linearly in an axial direction in the resin sealing portion, the cooling flow passage includes a resin flow passage having a flow passage wall surface formed of the cured resin material, and a tube provided separately from the cured resin material, At least one end of the tube is connected to the resin flow path.

2. The stator of claim 1 , wherein both ends of the tube are connected to the resin flow passage.

3. The difference between the linear expansion coefficient of the tube and the linear expansion coefficient of the cured resin of the resin flow path is 2×10 －５ / ℃ or less 3. A stator according to claim 1, wherein:

4. 3. The stator according to claim 1, wherein a difference between a thermal conductivity of the tube and a thermal conductivity of the cured resin of the resin flow passage is 30 W / (m·K) or less.

5. 3. The stator of claim 1, wherein the tube is a ceramic tube.

6. 3. The stator according to claim 1, wherein the tube is a glass tube.

7. 3. The stator according to claim 1, wherein the tube is a resin tube made of a thermosetting resin.

8. The stator according to claim 7 , wherein the resin material of the resin tube is the same as the resin material of the resin sealing portion.

9. 3. The stator according to claim 1, wherein the length of the tube is between 50% and 98% of the axial length of the slot.

10. The stator according to claim 1 , wherein a plurality of the tubes are provided in one flow passage provided in one slot.

11. A method for manufacturing a stator comprising the steps of: placing a stator core in a die; sealing coils in slots with a resin material; and having cooling channels extending linearly in an axial direction within the slots, the method comprising the steps of: a flow path pin preparation step of preparing a flow path pin to which a tube constituting a part of the cooling flow path is attached; a pin arrangement step of arranging the flow path pin to which the tube is attached inside the slot of the stator such that the tube is at a predetermined position within the slot; a resin molding process for filling a resin molding material in a region between the coil and the tube inside the slot so as to fill the periphery of the tube; a pin removal step of removing the flow path pin; A method for manufacturing a stator comprising the steps of:

12. 12. The method for manufacturing a stator according to claim 11, wherein the pin positioning process positions the tube attached to the flow path pin so that at least one end of the tube is covered with the resin molding material in the resin molding process as the predetermined position for positioning the tube.

13. The method for manufacturing a stator according to claim 11 , wherein the pin positioning step includes positioning the tube attached to the flow path pin so that the tube is covered with the resin molding material as the predetermined position for positioning the tube.

14. The difference between the linear expansion coefficient of the tube and the linear expansion coefficient of the cured resin of the resin flow path is 2×10 －５ The method for manufacturing a stator according to any one of claims 11 to 13, wherein the temperature is 0.15 to 1.5°C or less.

15. The method for manufacturing a stator according to any one of claims 11 to 13, wherein a difference between the thermal conductivity of the tube and the thermal conductivity of the cured resin of the resin flow path is 30 W / (m·K) or less.

16. The method for manufacturing a stator according to any one of claims 11 to 13, wherein the tube is a ceramic tube.

17. The method for manufacturing a stator according to any one of claims 11 to 13, wherein the tube is a glass tube.

18. The method for manufacturing a stator according to any one of claims 11 to 13, wherein the tube is a resin tube made of a thermosetting resin.

19. The method for manufacturing a stator according to claim 18, wherein a resin material of the resin tube is the same as the resin molding material.

20. The method for manufacturing a stator according to any one of claims 11 to 13, wherein the length of the tube is 50% or more and 98% or less of the axial length of the slot.

21. The method for manufacturing a stator according to any one of claims 11 to 13, wherein a plurality of the tubes are provided in one flow passage provided in one slot.

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