Foam adhesive flat wire, stator, and stator manufacturing method

Abstract

According to an embodiment of the present invention, a foam-bonded flat wire (10) is provided with a flat conductor (11) having a substantially rectangular cross-section, an enamel cover layer (12) provided on the outer surface of the flat conductor (11), and a foam-bonded layer (13) provided on the outer surface of the enamel cover layer (12) and capable of foaming and bonding at a predetermined temperature or higher. The thickness of the side surfaces (13c, 13d) of the foaming adhesive layer (13) can be reduced or zero when each side surface of the foaming adhesive flat wire (10) is not adjacent to another member compared with when the foaming adhesive flat wire (10) is adjacent to another member.

Description

Technical Field

[0001] This invention relates to foamed adhesive flat wires, stators, and stator manufacturing methods. Background Technology

[0002] In the stator of a rotating electrical machine, flat conductors with a roughly rectangular cross-section are mostly used as stator windings. The outer surface of the flat conductor is usually covered with an enameled coating.

[0003] When using flat conductors for winding, it is necessary to ensure vibration resistance, that is, to prevent changes in the relative positions of the flat conductors to each other or between the flat conductors and the stator core.

[0004] Therefore, the stator windings need to be cured with varnish.

[0005] Existing technical documents Patent documents Patent Document 1: Japanese Patent Application Publication No. 2022-34889 Summary of the Invention

[0006] The technical problem that the invention aims to solve When curing stator windings with varnish, deviations exist in the penetration and curing of the varnish depending on whether the stator winding is inside the slot or at the coil end, potentially reducing reliability. Furthermore, the management of conditions during the varnishing process and the time required for this process reduce production efficiency.

[0007] The purpose of this invention is to provide a foam-bonded flat wire, a stator, and a stator manufacturing method that provides stable curing of the winding, thereby improving the reliability of vibration resistance.

[0008] Methods for solving problems To achieve the above objectives, the foamed adhesive flat wire of the present invention is characterized by comprising: a flat conductor with a generally rectangular cross-section; an enameled layer disposed on the outer surface of the flat conductor; and a foamed adhesive layer disposed on the outer surface of the enameled layer that is capable of foaming at a specified temperature and is capable of bonding. Attached Figure Description

[0009] Figure 1 This is a partial cross-sectional view showing the foamed adhesive flat line of the first embodiment.

[0010] Figure 2 This is a partial cross-sectional view of the stator windings of the stator in the first embodiment.

[0011] Figure 3 This refers to the stator windings of the stator in the first embodiment. Figure 2 A partial cross-sectional view of section BB.

[0012] Figure 4 This refers to the stator windings of the stator in the first embodiment. Figure 2 Partial cross-sectional views of the CC and DD sections.

[0013] Figure 5 This is a partial cross-sectional view showing the foamed adhesive flat line of the second embodiment.

[0014] Figure 6 This is a partial longitudinal sectional view of the heated foamed sheet showing the foamed adhesive flat line of the second embodiment.

[0015] Figure 7 This is a perspective view illustrating the flat wire stator internal connection method in the stator manufacturing method of the third embodiment.

[0016] Figure 8 This is a longitudinal sectional view showing the cut of the flat wire stator internal connection method in the stator manufacturing method of the third embodiment.

[0017] Figure 9 This is a flowchart illustrating the sequence of the stator manufacturing method according to the third embodiment. Detailed Implementation

[0018] Hereinafter, the foamed adhesive flat line, stator, and stator manufacturing method according to embodiments of the present invention will be described with reference to the accompanying drawings. Common symbols will be used to denote identical or similar parts, and repeated descriptions will be omitted.

[0019] [First Implementation Method] Figure 1 This is a partial cross-sectional view showing the foamed adhesive flat line 10 of the first embodiment.

[0020] The foamed adhesive flat wire 10 has a flat conductor 11 with a rectangular cross-section extending along the length direction, an enameled layer 12 disposed on the outer periphery of the flat conductor, and a foamed adhesive layer 13 disposed on the outer periphery of the enameled layer 12.

[0021] Here, at the corner 11c of the flat conductor 11, that is, at each edge portion, in other words, at Figure 1 The four corners in the cross-sectional view may be chamfered or rounded, but the overall shape may also be roughly rectangular. Hereinafter, the cross-sectional shape will also be referred to as rectangular, including cases where the corners 11c are roughly rectangular.

[0022] The enameled layer 12 is formed with a substantially uniform thickness on all four sides of the foamed adhesive flat line. Here, "substantially uniform" means formed within the range of measurement accuracy under construction deviations and verification conditions.

[0023] The foamed adhesive layer 13 foams by heating or raising the temperature to a specified temperature or above, and thus performs its adhesive function. In the case of a thermoplastic resin, the specified temperature can be set as the glass transition temperature. Figure 1 In the diagram, the foamed adhesive layer 13 is shown to have a substantially uniform thickness on all four sides. However, as shown below, the thickness can vary depending on the conditions of the application area. Hereinafter, for ease of explanation, the upper portion in the cross-sectional view will be referred to as the upper surface 13a of the foamed adhesive layer, the lower portion as the lower surface 13b of the foamed adhesive layer, and the transverse portions as the side surfaces 13c and 13d of the foamed adhesive layer.

[0024] Figure 2 This is a perspective view showing a portion of the stator winding 24 of the stator 20 according to the first embodiment. The stator 20 is arranged radially outside a rotor (not shown) in a manner that surrounds the rotor. The stator 20 has a stator core 21 and a stator winding 24.

[0025] For ease of explanation, the following will be used... Figure 2 The direction pointing upwards is called the radial outward, the transverse direction is called the circumferential direction, and the direction perpendicular to the radial and circumferential directions is called the axial direction.

[0026] Stator teeth 23 are formed circumferentially (one circumference) and spaced apart from each other in the stator core 21. In addition, stator slots 22 are formed by the stator teeth 23 that are adjacent to each other in the circumferential direction.

[0027] As part of the stator winding 24, the first coil segment 25a and the second coil segment 25b are shown inserted into the stator slot 22. Here, the first coil segment 25a and the second coil segment 25b, etc., have two straight portions 25c extending axially and a connecting portion connecting these two straight portions 25c. Each straight portion 25c is inserted into the stator slot 22. The two straight portions 25c of the same coil segment are inserted into different stator slots 22.

[0028] exist Figure 2 The image shows a case where most of the straight portion 25c of one side of the first coil segment 25a and most of the straight portion 25c of one side of the second coil segment 25b are housed in the same stator slot 22 and are adjacent to each other vertically.

[0029] The above-mentioned Figure 1 express Figure 2 The shape of section AA. The section AA is where the straight portions 25c of the first coil segment 25a and the second coil segment 25b are housed within the stator slot 22. Here, the first coil segment 25a and the second coil segment 25b are adjacent to each other, and the first coil segment 25a and the second coil segment 25b are respectively connected to the inner wall 22a of the slot ( Figure 2 The adjacent parts. That is, in each of the first coil segment 25a and the second coil segment 25b, the four sides are adjacent to other conductor parts.

[0030] In such locations, the thickness of the two sides of the foam adhesive layer 13 of the foam adhesive flat line 10, namely the upper surface 13a, the lower surface 13b, and the sides 13c and 13d of the foam adhesive layer, is substantially uniform. Alternatively, the thickness can be varied according to the potential difference with adjacent objects.

[0031] Figure 3 This refers to the stator winding 24 of the stator in the first embodiment. Figure 2 A partial cross-sectional view of section BB.

[0032] exist Figure 2 In the BB section, the first coil segment 25a and the second coil segment 25b are adjacent to each other, but there are no objects adjacent to the side surfaces of the first coil segment 25a and the second coil segment 25b. That is, in the first coil segment 25a and the second coil segment 25b, adjacent objects only exist on the upper surface 13a or the lower surface 13b of the foam adhesive layer. When the coil segment is not the outermost or innermost radially, it is only the upper surface 13a and the lower surface 13b of the foam adhesive layer.

[0033] Thus, in areas where there are no objects adjacent to the sides of the first coil segment 25a and the second coil segment 25b, the foamed adhesive layer 13 can bond to the adjacent objects without foaming or expanding. Therefore, in such cases, as Figure 3 As shown, the thickness of the foamed adhesive layer 13 on the sides 13c and 13d of the foamed adhesive layer can be less than the thickness of the foamed adhesive layer 13 on the upper surface 13a and the lower surface 13b of the foamed adhesive layer. Alternatively, it can be formed locally, for example, by spacing it apart from each other in the length direction, or it can be omitted.

[0034] Figure 4 This refers to the stator winding 24 of the stator in the first embodiment. Figure 2 Partial cross-sectional views of the CC section and the DD section.

[0035] Figure 2 The CC and DD sections are the portions on all sides of the first coil segment 25a and the second coil segment 25b where there are no adjacent objects. In these portions, the foamed adhesive layer 13 does not need to foam or expand to adhere to the adjacent objects. Therefore, in such cases, as... Figure 4As shown, the thickness of the foamed adhesive layer 13 at the upper surface 13a, lower surface 13b, and sides 13c and 13d of the foamed adhesive layer can be less than the thickness in the first embodiment. Alternatively, it can be formed locally along the length direction, or it can be omitted.

[0036] In each part of the stator 20 as described above, the foamed adhesive layer 13 expands in volume by heating. Furthermore, when the foamed adhesive layer 13 comes into contact with an adjacent component, the foamed adhesive flat wire 10 can be bonded to that component. As a result, the stator winding 24 can be stably cured.

[0037] [Second Implementation] Figure 5 This is a partial cross-sectional view showing the foamed adhesive flat line 10a of the second embodiment. This embodiment is a variation of the first embodiment, in which a heated foamed sheet 14 is wound around the surface of the enameled layer 12 as the foamed adhesive layer 13.

[0038] Figure 6 This is a partial longitudinal sectional view of the heated foamed sheet 14 showing the foamed adhesive flat line 10a of the second embodiment.

[0039] The heat-foamed sheet 14 includes a film substrate 14a, an adhesive layer 14b formed on the surface of the film substrate 14a, a nonwoven fabric layer 14c disposed on the outer surface of the adhesive layer 14b, and a foamed adhesive layer 14d formed on the outer surface of the nonwoven fabric layer 14c. The foamed adhesive layer 14d is foamed by heating to a predetermined temperature or higher. Here, the predetermined temperature is, for example, the glass transition temperature in the case of thermoplastic resins, for example, about 100°C to 120°C.

[0040] The film substrate 14a can be made of resin films such as polyester resin, polyamide resin, polyimide resin, polysulfone resin, and polyetherketone resin.

[0041] The adhesive layer 14b bonds the nonwoven fabric layer 14c to the film substrate 14a. The material of the adhesive layer 14b may be a thermoplastic resin-based, thermosetting resin-based, or elastic adhesive.

[0042] The nonwoven layer 14c can be, for example, a nonwoven fabric using fibers such as cellulose fiber, polyester fiber, nylon fiber, aramid fiber, polyphenylene sulfide fiber, liquid crystal polymer fiber, glass fiber, metal fiber, carbon fiber, etc.

[0043] The foamed adhesive layer 14d comprises epoxy resin, curing agent, thermoplastic resin, and foaming agent. Additionally, other additives such as curing accelerators and fillers may be included as needed.

[0044] The foamed adhesive flat line 10a of this embodiment, as described above, is easy to assemble by winding the heated foamed sheet 14 as the foamed adhesive layer 13 onto the surface of the enameled layer 12, and in addition, it can achieve the same effect as the first embodiment.

[0045] [Third Implementation Method] Figure 7 This is a perspective view illustrating the flat-wire stator internal connection method in the stator manufacturing method of the third embodiment. Additionally, Figure 8 This is a longitudinal sectional view showing the cut in the flat wire stator internal connection method of the stator manufacturing method in the third embodiment.

[0046] This embodiment is a variation of the first embodiment. Typically, a coil segment having two straight sections and a connecting section linking them is inserted from one end of the stator core 21 and connected to the other end. However, this embodiment involves inserting the coil segment from both sides of the stator core 21 and connecting each straight section in the stator slot 22 (…). Figure 8 The connection method in the case of inner join.

[0047] Specifically, such as Figure 7 As shown, the straight portion of the coil segment inserted from the first end 21a of the stator core 21, namely the first flat wire 17a, and the straight portion of the coil segment inserted from the second end 21b of the stator core 21, namely the second flat wire 17b, are connected at the cut-out portion 18 in the same stator slot 22.

[0048] like Figure 8 As shown, a tapered first cut 18a is formed at the front end of the first flat line 17a. Additionally, a tapered second cut 18b is formed at the front end of the second flat line 17b. At the cut portions 18, the tapered surfaces of the first cut 18a and the second cut 18b are in close contact. This state corresponds to the step S03, which will be described below, where the cut portions are in close contact with each other.

[0049] Figure 9 This is a flowchart illustrating the steps of the stator manufacturing method according to the third embodiment.

[0050] First, assemble the stator core 21 (step S01).

[0051] Next, preparation is carried out for forming each coil segment with slits (step S02). Specifically, first, the front end of the flat conductor 11 of the straight portion of each coil segment is cut (step S02a). Next, each coil segment is formed (step S02b). That is, a coil segment having two straight portions and a connecting portion is made.

[0052] It should be noted that the assembly step S01 of the stator core 21 and the preparation step S02 of each coil segment can also be performed in parallel or in reverse order, regardless of their order.

[0053] Next, the coil segment setting step S03 is performed.

[0054] First, the straight portion of the coil segment is inserted into the stator slot 22 from both axial sides (step S03a). Specifically, the first coil segment 26a is inserted axially from the first end 21a of the stator core 21 into the first stator slot 22 and the second stator slot to a predetermined depth. Additionally, the second coil segment 26b is inserted axially from the second end 21b of the stator core 21 into the first stator slot 22 and the second stator slot to a predetermined depth. Here, in Figure 7 , 8 The diagram shows the case where the first flat line 17a of the straight portion of the first coil segment 26a and the second flat line 17b of the straight portion of the second coil segment 26b are housed in the same first stator slot 22.

[0055] Additionally, the coil segment setting in step S03 can involve inserting all coil segments simultaneously. Alternatively, for example, they can be inserted layer by layer.

[0056] Next, the tightness of the cut portions is checked and the coil segment is fixed (step S03b). Checking for tightness is not mandatory here. Furthermore, even if checking is performed, it is difficult to ensure tightness of all cut portions 18; the innermost straight portion located in the stator slot 22 can be observed from the inner circumference of the stator core 21. Alternatively, as a sampling inspection, only a specified number can be checked. Furthermore, if the first flat wire 17a and the second flat wire 17b are inserted to a specified depth, as long as the tightness of the first cut 18a and the second cut 18b at their front ends can be known in advance, it can be replaced by checking that the specified depth is achieved. Additionally, the coil segment can be fixed as needed.

[0057] Next, it is determined whether step S03 (step S04) has been performed on all coil segments. If it is not determined that step S03 has been performed on all coil segments (step S04 no), steps S03 and S04 are repeated.

[0058] like Figure 8As shown, since the tapers of the first cut 18a and the second cut 18b are formed with the same inclination, the first flat wire 17a and the second flat wire 17b are tightly attached when inserted and their front ends are in contact with each other. Furthermore, the enameled layer 12 and the foamed adhesive layer 13 on the outer side of each flat conductor 11 are also formed with the same inclination and are tightly attached to each other. Here, "tightly attached" means within the range of the taper inclination processing accuracy of the first flat wire 17a and the second flat wire 17b, as well as the mutual arrangement accuracy of the first flat wire 17a and the second flat wire 17b.

[0059] If it is determined that step S03 is to be performed on all coil segments (step S04 is), then the foam bonding flat wire 10 or 10a is bonded and fixed (step S05).

[0060] In detail, first, the external terminals (not shown) are connected to the power supply (step S05a). This connection may also include temporary wiring. Next, the flat conductors 11 are energized (step S05b). The energization is carried out for a predetermined time. Here, the predetermined time is the time required for the flat conductors 11 to fuse together and for the foam adhesive layer 13 at the cutout 18 to cover the flat conductors 11. Finally, the adhesion of the foam adhesive layers 13 to each other is checked (step S05c). Here, it is difficult to check all the cutouts 18, so the straight portion located at the innermost circumference of the stator slot 22 can be observed from the inner circumference side of the stator core 21. Alternatively, as a sampling inspection, only a predetermined number can be checked.

[0061] As described above, assemble and manufacture a stator 20 having a stator core 21 and a stator winding 24.

[0062] According to this embodiment, even when the coil segments are inserted from both sides of the stator core 21 and their respective straight portions are connected in the stator slot 22, the winding can be stably solidified.

[0063] Based on the embodiments described above, a foam-bonded flat wire, a stator, and a stator manufacturing method can be provided that enables stable curing of the winding and improves reliability in terms of vibration resistance.

[0064] [Other Implementation Methods] The embodiments of the present invention have been described above, but these embodiments are provided as examples and are not intended to limit the scope of the invention. Furthermore, features of each embodiment can be combined. These embodiments can be implemented in various other ways, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. The embodiments and their variations are included within the scope and spirit of the invention, and also within the scope of the invention described in the patent claims and its equivalents.

[0065] Explanation of reference numerals in the attached figures 10, 10a…Foamed adhesive flat wire, 11…Flat conductor, 11c…Corner, 12…Enamelled layer, 13…Foamed adhesive layer, 13a…Upper surface of foamed adhesive layer, 13b…Lower surface of foamed adhesive layer, 13c, 13d…Side surface of foamed adhesive layer, 14…Heated foamed sheet, 14a…Film substrate, 14b…Adhesive layer, 14c…Non-woven fabric layer, 14d…Foamed adhesive layer, 17a…First flat wire, 17b…Second flat wire, 18…cut section, 18a…first cut, 18b…second cut, 20…stator, 21…stator core, 21a…first end, 21b…second end, 22…stator slot, 22a…slot inner wall, 23…stator tooth, 24…stator winding, 25a…first coil segment, 25b…second coil segment, 25c…straight section, 26a…first coil segment, 26b…second coil segment.

Claims

1. A foam-bonded flat wire, characterized in that, have: A flat conductor with a roughly rectangular cross-section; An enameled layer is disposed on the outer surface of the flat conductor; and A foamed adhesive layer is disposed on the outer surface of the enameled layer and is capable of foaming at a specified temperature and bonding.

2. The foamed adhesive flat wire according to claim 1, characterized in that, When the foamed adhesive layer is not adjacent to other components on any side of the foamed adhesive flat line, the thickness of the foamed adhesive layer on that side is reduced or zero compared to when it is adjacent to other components.

3. The foamed adhesive flat wire according to claim 1, characterized in that, The foamed adhesive layer is a heated foamed sheet. The heated foamed sheet has: a film substrate or a nonwoven fabric substrate, and a foamed adhesive layer formed on the surface of the film substrate or the nonwoven fabric substrate.

4. The foamed adhesive flat wire according to claim 1, characterized in that, The foamed adhesive layer is a heated foamed sheet. The heated foamed sheet has a film substrate, an adhesive layer formed on the surface of the film substrate, a nonwoven fabric layer disposed on the outer surface of the adhesive layer, and a foamed adhesive layer formed on the outer surface of the nonwoven fabric layer.

5. The foamed adhesive flat wire according to claim 1, characterized in that, On the four sides of the flat conductor on which the foamed adhesive layer is formed, the foamed adhesive layer is present only on two opposite sides of the four sides.

6. The foamed adhesive flat wire according to claim 1, characterized in that, On each side of the flat conductor where the foamed adhesive layer is formed, the regions of the foamed adhesive layer that are locally formed exist at intervals along the length direction of the flat conductor.

7. A stator, characterized in that, have: A stator core having a plurality of stator slots spaced apart circumferentially on its inner circumferential side; and A stator winding using foam-bonded flat wire as described in any one of claims 1 to 6, wherein a portion of the stator winding is housed within the stator slot.

8. A stator, characterized in that, In the stator winding using a stator core having a plurality of stator slots spaced apart circumferentially on its inner circumferential side and the foamed adhesive flat wire as described in claim 6, and a portion of which is housed within the stator slots, the two sides having the foamed adhesive layer are circumferential surfaces of the stator slots.

9. The stator according to claim 8, characterized in that, The stator slot also contains slot insulation paper.

10. A method for manufacturing a stator, characterized in that, have: The steps for assembling a stator core with multiple stator slots; The steps to prepare for forming the slit coil segments; The step of inserting the first coil segment axially from the first end side of the stator core into the first stator slot and the second stator slot to a specified depth; The step of inserting the second coil segment axially from the second end side of the stator core into the first stator slot and the second stator slot to a specified depth; as well as The steps involve bonding and fixing foamed flat wires by heating flat conductors. The specified depth is the depth at which the cut of the first coil segment and the cut of the second coil segment are in close contact in the first stator slot.

11. The stator manufacturing method according to claim 10, characterized in that, The heating is performed by generating heat through an electric current applied to the foamed adhesive flat wire.

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