Method for manufacturing coil for rotating electrical machine

Abstract

The invention provides a method for manufacturing a coil for a rotating electrical machine. The coil for the rotating electric machine is provided with a first side surface and a second side surface which face opposite directions, and the first side surface and the second side surface are respectively provided with a groove (50) along the length direction. In the manufacturing of the coil for the rotating electric machine, when the groove (50) is press-molded on one of the first side surface and the second side surface, press-molding of the other groove (50) is started.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a coil for a rotating electrical machine. Background Art

[0002] As a rotating electrical machine such as an electric motor or a generator, there is a structure in which a rotatable rotor is disposed radially inside a ring-shaped stator. The stator has a stator core and a coil (coil for a rotating electrical machine) wound around the stator core. The stator core is integrally formed with, for example, a cylindrical back yoke and a plurality of teeth protruding radially inward from the back yoke. Slots are formed between the plurality of teeth adjacent to each other in the circumferential direction. The coil is wound around each tooth through the slots disposed on both sides of the tooth.

[0003] In such a rotating electrical machine, the coil becomes hot during use, and thus it is desired to efficiently cool the coil. As a method for efficiently cooling the coil of the rotating electrical machine, a method of flowing a coolant around the coil is known (for example, see Japanese Patent No. 7139969).

[0004] In the rotating electrical machine described in Japanese Patent No. 7139969, the coil (coil for a rotating electrical machine) wound around the teeth of the stator core is formed of a flat wire. And, a substantially arc-shaped groove is formed on the side surface (side surface facing a direction crossing the extending direction) of the insertion portion passing through the slot in the coil. The coolant introduced from one end side in the axial direction of the stator core flows into this groove, and the coolant flows out to the other end side in the axial direction. At this time, the coil is efficiently cooled by the coolant flowing through the groove. Summary of the Invention

[0005] In the case where the above-described grooves are formed on both side surfaces of the coil facing opposite directions, the coil is placed on a placement table with one side surface facing upward, and in this state, a male mold for forming the groove is lowered to press-mold the groove on one side surface of the coil. Then, after the press-molding of the groove on one side surface is completed, the coil is reversed so that the other side surface of the coil faces upward, and the groove is press-molded on the other side surface in the same manner as on the one side surface by the male mold.

[0006] If grooves are formed on two opposite side surfaces of the coil, when pressing the male mold on one side surface (the surface facing the upper side), a compressive load acts between the mountain-shaped pressing portion of the male mold pressed against the substantially central upper surface in the width direction of the coil and the flat upper surface of the mounting table. At this time, the other side surface of the coil (the surface facing the lower side) abuts against the upper surface of the mounting table in a wide area in the width direction. Therefore, in the cross section of the coil, a large stress acts between the substantially central area in the width direction of the upper surface pressed by the male mold and the wide area in the width direction where the upper surface of the mounting table abuts. That is, the portion where the large stress acts gradually expands downward in the cross section of the coil, or branches into two in the width direction and is distributed.

[0007] And, if the coil is then reversed so that the other side surface of the coil faces upward and the male mold is pressed on this surface, a compressive load also acts between the pressing portion of the upper male mold and the upper surface of the mounting table.

[0008] At this time, in the cross section of the coil, the portion where the large stress acts is distributed between the substantially central area in the width direction of the upper surface pressed by the male mold and the wide area in the width direction where the upper surface of the mounting table abuts. And in the cross section of the coil, a part of the stress generated when the groove is formed on one side surface remains. Therefore, in the cross section of the formed coil, the stress generated when the groove is formed on one side surface and the stress generated when the groove is formed on the other side surface remain in a large range in a combined form. Therefore, when grooves are formed on two opposite side surfaces of the coil by the above method, large deformation is likely to occur in the coil.

[0009] Therefore, the present invention provides a method for manufacturing a rotating electric machine coil that is difficult to generate unnecessary deformation when grooves are formed on opposite side surfaces.

[0010] A method for manufacturing a rotating electric machine coil according to an aspect of the present invention is a method for manufacturing a rotating electric machine coil having a first side surface and a second side surface facing opposite directions and having grooves along the length direction provided on the first side surface and the second side surface, respectively. The method for manufacturing the rotating electric machine coil includes the following steps: when pressing and forming the groove on one of the first side surface and the second side surface, starting to press and form the groove on the other of the first side surface and the second side surface.

[0011] In the method for manufacturing a coil for a rotating electric machine according to the solution of the present invention, the pressing process for forming a groove on the first side surface and the pressing process for forming a groove on the second side surface are performed overlappingly in time. At this time, the direction of the load applied to the first side surface for forming a groove and the direction of the load applied to the second side surface for forming a groove become directions facing each other. Therefore, the regions with high stress concentrate in the area within the coil that linearly connects the pressing portion for forming a groove on the first side surface and the pressing portion for forming a groove on the second side surface, and it is difficult for the regions with high stress to spread to other parts. Therefore, after the groove processing is completed, it is difficult for unnecessary parts within the cross-section of the coil to deform.

[0012] In addition, when this method is adopted, since it is difficult for unnecessary stress to be generated in the unnecessary parts within the cross-section of the coil during processing, the load required for processing can be reduced, and smooth processing of the coil for a rotating electric machine can be achieved.

[0013] It is also possible to make at least one of the start timing of the pressing process for the first side surface and the second side surface and the end timing of the pressing process for the first side surface and the second side surface coincide.

[0014] In this case, when the start timing of the pressing process for the first side surface and the second side surface coincides, the deformation load that rapidly increases at the initial stage of pressing can be concentrated between the pressing portions on both side surfaces, and the situation where the regions with high stress spread to the surroundings can be prevented. In addition, when the end timing of the pressing process for the first side surface and the second side surface coincides, even if there are some deformation deviations between the first side surface and the second side surface before the end of the pressing process, the deformation deviations can be finally corrected.

[0015] It is also possible to make the start timing of the pressing process for the first side surface and the second side surface coincide and make the end timing of the pressing process for the first side surface and the second side surface coincide.

[0016] In this case, the deformation load that rapidly increases at the initial stage of pressing can be concentrated between the pressing portions on the first and second side surfaces, and the deformation deviations between the first side surface and the second side surface can be finally corrected.

[0017] It is also possible that when performing the pressing process on the first side surface and the second side surface, the support mold clamps the pair of other side surfaces facing in opposite directions except for the first side surface and the second side surface.

[0018] In this case, by clamping the pairs of the other sides with the support molds, rotation of the rotating electric machine coil during press forming can be suppressed. Therefore, press forming of the rotating electric machine coil can be performed with high precision.

[0019] Alternatively, the support mold may be spring-biased so as to be displaceable upon input of a load.

[0020] In this case, since the support mold that clamps the rotating electric machine coil is spring-biased so as to be displaceable, impact associated with input of a large load during press forming can be absorbed by the function of the spring. Therefore, in the case where this method is employed, detachment and deviation of the coil from the processing apparatus can be eliminated, and processing of the coil can be stably performed.

[0021] In the method for manufacturing a coil for a rotating electric machine according to the aspect of the present invention, when press forming a groove in one of the first side and the second side, press forming of the groove in the other side is started, so that press forming of the first side and press forming of the second side can be performed overlappingly in time. Also, press forming of the first side and press forming of the second side can be performed from directions facing each other. Therefore, in the case where the method for manufacturing a coil for a rotating electric machine according to the aspect of the present invention is employed, when forming grooves on sides facing in opposite directions, unnecessary deformation is less likely to occur in the coil. Therefore, the product quality of the coil for a rotating electric machine can be further improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is a longitudinal sectional view of the rotating electric machine according to the embodiment.

[0023] Figure 2 is a sectional view of the rotating electric machine according to the embodiment along line II-II Figure 1 of.

[0024] Figure 3 is a perspective view of the processing apparatus for the coil for a rotating electric machine according to the embodiment.

[0025] Figure 4 is a schematic sectional view of the processing apparatus for the coil for a rotating electric machine according to the embodiment.

[0026] Figure 5 is a diagram showing the processing steps (A), (B), (C), (D) of the comparative example and the pressure distribution inside the coil at this time.

[0027] Figure 6 is a diagram showing the processing steps (A), (B) of the embodiment and the pressure distribution inside the coil at this time. DETAILED DESCRIPTION

[0028] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0029] Figure 1 is a longitudinal sectional view of the rotating electrical machine 1 of the embodiment.

[0030] The rotating electrical machine 1 of the present embodiment includes a stator 10 and a rotor 11. The stator 10 and the rotor 11 are housed inside a rotating electrical machine housing 12. The stator 10 is fixed inside the rotating electrical machine housing 12 by means of fastening connection with bolts 13 or the like. The stator 10 includes a cylindrical stator core 14 and a plurality of coils 15 wound around the stator core 14. The rotor 11 is disposed radially inside the stator core 14 (stator 10) so as to be rotatable.

[0031] It should be noted that the coil 15 constitutes the rotating electrical machine coil in the present embodiment.

[0032] The rotor 11 has a permanent magnet (not shown) mounted near its outer peripheral surface. In addition, the rotor 11 is supported by a sleeve 16 so as to be integrally rotatable on a rotating shaft 17. The rotating shaft 17 becomes an output shaft when the rotating electrical machine 1 is used as a motor, and becomes a power input shaft when the rotating electrical machine 1 is used as a generator. The rotating shaft 17 and the sleeve 16 are rotatably supported by the rotating electrical machine housing 12 via bearings 18.

[0033] In the following description, the direction parallel to the rotation axis C of the rotor 11 is referred to as the axial direction, the rotation direction of the rotor 11 is referred to as the circumferential direction, and the radial direction of the rotor 11 orthogonal to the axial direction and the circumferential direction is referred to as the radial direction.

[0034] Annular first side housings 19 and second side housings 20 are disposed on one end side and the other end side in the axial direction of the stator core 14. Main portions of the first side housings 19 and the second side housings 20 are formed by the rotating electrical machine housing 12.

[0035] The first side housing 19 covers, from the outside, one end face in the axial direction of the stator core 14 and the exposed portion of the coil 15 protruding from the end face. The first side housing 19 and one end face in the axial direction of the stator core 14 together form an annular first liquid chamber 21. An introduction port 24 for introducing a coolant 23 into the first liquid chamber 21 is formed in the first side housing 19. The introduction port 24 is connected to a circulation circuit 25 of the coolant 23. The coolant 23 introduced into the first liquid chamber 21 cools the exposed portion of the coil 15 protruding from one end face of the stator core 14, and then flows into the other end side in the axial direction of the stator core 14 through the inside of the stator core 14.

[0036] The second side housing 20 covers axially the other end face of the stator core 14 and the exposed portion of the coil 15 protruding from the end face from the outside. The second side housing 20 and the other end face of the stator core 14 axially form an annular second liquid chamber 22. The coolant 23 introduced into the first liquid chamber 21 flows into the second liquid chamber 22 through the inside of the stator core 14. The coolant 23 introduced into the second liquid chamber 22 cools the exposed portion of the coil 15 protruding from the other end face of the stator core 14. A discharge port 26 for discharging the coolant 23 in the second liquid chamber 22 to the outside is formed in the second side housing 20. The discharge port 26 is connected to the circulation circuit 25 of the coolant 23. The coolant 23 that has cooled the coil 15 in the second liquid chamber 22 returns from the discharge port 26 to the circulation circuit 25.

[0037] A feed pump P is connected in the middle of the circulation circuit 25. A heat exchanger OC is connected to the upstream side of the feed pump P in the circulation circuit 25, and the heat exchanger OC cools the coolant 23 by heat exchange with external gas. The downstream side of the feed pump P is connected to the introduction port 24. In addition, the upstream side of the heat exchanger OC in the circulation circuit 25 is connected to the discharge port 26.

[0038] Figure 2 is a cross-sectional view taken along the II-II line of the rotating electrical machine 1 Figure 1 of.

[0039] The stator core 14 is formed, for example, by laminating a plurality of electromagnetic steel sheets axially. As Figure 2 shown, the stator core 14 is integrally formed with a cylindrical back yoke 27 and a plurality of teeth 28 protruding radially inward from the inner peripheral portion of the back yoke 27. The back yoke 27 is formed such that the center of the cylinder coincides with the rotation axis C.

[0040] The teeth 28 are arranged at intervals in the circumferential direction. When viewed axially, the teeth 28 are formed in a T shape. That is, the teeth 28 are integrally formed with a tooth body 29 protruding radially inward from the inner peripheral portion of the back yoke 27 and flange portions 30 protruding from the radially inner ends of the tooth body 29 toward both sides in the circumferential direction.

[0041] A slot 31 that is open radially inward is formed between the teeth 28 adjacent in the circumferential direction. The slot 31 is formed by surrounding side walls of adjacent teeth 28 facing each other and the inner peripheral wall of the back yoke 27. The side walls of each tooth 28 are formed by the side portions of the tooth body 29 and the side portions of the flange portions 30. The portion of the slot 31 formed by the side portions of the left and right tooth bodies 29 is substantially formed with a fixed width. In addition, the width of the portion of the slot 31 formed by the side portions of the left and right flange portions 30 is narrower than the width of the portion formed by the side portions of the left and right tooth bodies 29.

[0042] It should be noted that the openings 40 on the radially inner sides of the respective slots 31 are formed by being clamped by the front end portions of the flange portions 30 on the left and right (both circumferential sides) of the slots 31. In addition, each slot 31 penetrates the stator core 14 in the axial direction.

[0043] The coil 15 is provided with, for example, three phases of U-phase, V-phase, and W-phase. The coil 15 is formed, for example, by connecting a plurality of segmented coils to each other. The outer surface of the metallic wire 41 of the coil 15 is covered with an insulating coating film 42. In addition, the coil 15 is formed of flat wire. That is, the shape of the cross section of the coil 15 orthogonal to the extending direction is substantially formed in a rectangular shape.

[0044] Each coil 15 passes through the slot 31 of the stator core 14 in the axial direction and is wound around the corresponding tooth 28 in this state.

[0045] Hereinafter, the portion of the coil 15 passing through the slot 31 will be referred to as the "insertion portion 15a", and the portion exposed to the outside of the slot 31 and pulled back in the direction of the other slot 31 will be referred to as the "pull-back portion 15b".

[0046] As Figure 2 shown, the insertion portions 15a of the coil 15 pass through the respective slots 31 in multiple layers. The multiple insertion portions 15a passing through the same slot 31 are arranged in a row along the radial direction. In the present embodiment, for example, five insertion portions 15a pass through the same slot 31. However, the number of insertion portions 15a passing through the same slot 31 is not limited thereto and can be arbitrarily set.

[0047] The multiple insertion portions 15a inserted and arranged in each slot 31 are covered with a sheet of a foaming insulating member 43 in a state of being bundled side by side in a row. The foaming insulating member 43 can be, for example, a member in which a foaming adhesive is disposed (coated) on the surface of an electrically insulating base sheet (the surface facing outward in the state of covering the insertion portion 15a) and a non-foaming adhesive is disposed (coated) on the back surface of the base sheet. The foaming insulating member 43 is inserted and arranged in the corresponding slot 31 together with these insertion portions 15a in a state of covering the peripheries of the multiple insertion portions 15a. Then, the foaming insulating member 43 foams in the corresponding slot 31 by performing a heat treatment or the like. As a result, a part of the outer surface of the foaming insulating member 43 adheres to the inner wall of the slot 31.

[0048] As described above, even after the insertion portion 15a of the coil 15 and the foamed insulating member 43 are disposed in the slot 31, a gap for communicating the one end side and the other end side in the axial direction of the stator core 14 is ensured inside the slot 31. This gap forms a coolant passage 44 for causing the coolant introduced into the first liquid chamber 21 to flow toward the second liquid chamber 22 side. Specifically, the gap forming the coolant passage 44 is, for example, the gap between the inner surface of the foamed insulating member 43 and the insertion portion 15a, the gap between adjacent insertion portions 15a, and the gap between the outer surface of the foamed insulating member 43 and the inner wall of the slot 31. The coolant 23 flowing in the coolant passage 44 in the slot 31 absorbs the heat of the insertion portion 15a of the coil 15.

[0049] On the side surface facing the radially inner side and the side surface facing the radially outer side of each insertion portion 15a disposed in the slot 31, a groove 50 extending along the axial direction of the stator core 14 is formed. The groove 50 is formed to be recessed substantially in an arc shape toward the central region in the width direction of the insertion portion 15a.

[0050] When a plurality of insertion portions 15a and the foamed insulating member 43 are disposed in the slot 31 together, the groove 50 forms a gap (flow-through gap) extending substantially along the axial direction between the opposing side surfaces of the insertion portions 15a adjacent in the radial direction, or between the side surface of the insertion portion 15a and the inner surface of the foamed insulating member 43.

[0051] It should be noted that, in the present embodiment, the groove 50 formed on the side surface of the coil 15 constitutes a coolant flow groove. In addition, in the present embodiment, the groove 50 is also formed in the retracting portion 15b of the coil 15 so as to be continuous with the groove 50 of the insertion portion 15a.

[0052] In addition, as Figure 1 shown, the first side portion housing 19 on the one end side in the axial direction of the stator core 14 includes a first inner peripheral wall 32 facing the first liquid chamber 21. The first inner peripheral wall 32 projects cylindrically from the end portion on the radially inner side of the end side wall 33 of the first side portion housing 19 located at the axially outer end of the first liquid chamber 21 toward the end surface on one side in the axial direction of the rotor 11. In the case of the present embodiment, the first inner peripheral wall 32 is composed of a peripheral wall main body portion 12a integrally formed with the rotating electrical machine housing 12 (end side wall 33) and a separate cylindrical member 34 mounted on the outer peripheral surface at the extending end side of the peripheral wall main body portion 12a. The space between the peripheral wall main body portion 12a and the cylindrical member 34 is sealed by an annular seal member 60.

[0053] However, the first inner peripheral wall 32 may also be integrally formed with the rotating electrical machine housing 12 (end side wall 33) as a whole.

[0054] In addition, a second side housing 20 on the other axial end side of the stator core 14 includes a second inner peripheral wall 35 facing the second liquid chamber 22. The second inner peripheral wall 35 protrudes cylindrically from an end portion on the radially inner side of an end side wall 36 of the second side housing 20 located at the outer axial end of the second liquid chamber 22 toward the end face on the other axial side of the rotor 11. In the case of the present embodiment, the second inner peripheral wall 35 is integrally formed with the rotating electric machine housing 12 (end side wall 36).

[0055] However, the second inner peripheral wall 35 may also be composed of a peripheral wall main body portion integral with the rotating electric machine housing 12 (end side wall 36) and a separate cylindrical member, similarly to the first inner peripheral wall 32.

[0056] A cylindrical cover member, i.e., an annular partition wall 37, is provided between the outer peripheral surface of the first inner peripheral wall 32 of the first side housing 19 and the outer peripheral surface of the second inner peripheral wall 35 of the second side housing 20. The annular partition wall 37 is formed of, for example, a resin material. However, the annular partition wall 37 may also be formed of other raw materials such as a metal material. The annular partition wall 37 has a first end portion 37f facing the inside of the first liquid chamber 21, a second end portion 37s facing the inside of the second liquid chamber 22, and a partition wall main body portion 37b located between the first end portion 37f and the second end portion 37s and facing the inner peripheral surface of the stator core 14. The first end portion 37f is formed to have the same inner diameter as the partition wall main body portion 37b. A middle portion in the extending direction of the second end portion 37s is reduced in diameter stepwise with respect to the partition wall main body portion 37b.

[0057] The inner peripheral surface of the first end portion 37f is slidably fitted to the outer peripheral surface of the cylindrical member 34 of the first inner peripheral wall 32. An annular groove 38f is formed on the outer peripheral surface of the cylindrical member 34, and an annular sealing member 39f such as an O-ring is fitted in the annular groove 38f. The space between the cylindrical member 34 (first inner peripheral wall 32) and the first end portion 37f (annular partition wall 37) is hermetically sealed by the sealing member 39f in a liquid-tight manner.

[0058] In the present embodiment, the first end portion 37f constitutes a guiding member inside the first liquid chamber 21, which guides the coolant in the first liquid chamber 21 to the slot 31 on the axial one end side of the stator core 14.

[0059] The inner peripheral surface of the reduced-diameter portion of the second end portion 37s is slidably fitted to the outer peripheral surface of the second inner peripheral wall 35. An annular groove 38s is formed on the outer peripheral surface of the second inner peripheral wall 35, and an annular sealing member 39s such as an O-ring is fitted in the annular groove 38s. The space between the second inner peripheral wall 35 and the second end portion 37s (annular partition wall 37) is hermetically sealed by the sealing member 39s in a liquid-tight manner.

[0060] As described above, the first end portion 37f of the annular partition wall 37 is liquid-tightly fitted to the first inner peripheral wall 32 of the first side housing 19, and the second end portion 37s is liquid-tightly fitted to the second inner peripheral wall 35 of the second side housing 20. The annular partition wall 37 separates the radially inner region of the stator core 14 installed inside the rotating electric machine housing 12 from the outer peripheral surface of the rotor 11. Therefore, even if there is a case where the coolant 23 leaks from the slots 31 of the stator core 14 to the radially inner region, it is possible to prevent the coolant 23 from flowing into the outer peripheral surface side of the rotor 11.

[0061] In addition, a bulging portion that bulges radially outward from the outer peripheral surface of the main body portion 37b of the partition wall is provided on the outer peripheral surface of the first end portion 37f of the annular partition wall 37. The end portion on the stator core 14 side of this bulging portion stands up radially outward stepwise with respect to the outer peripheral surface of the main body portion 37b of the partition wall. The standing end surface abuts against the end surface on one axial end side of the stator core 14.

[0062] As Figure 2 shown, the outer peripheral surface of the main body portion 37b of the annular partition wall 37 is maintained in a state of abutting against the inner peripheral surface of the stator core 14. In addition, the inner peripheral surface of the main body portion 37b of the annular partition wall 37 faces the outer peripheral surface of the rotor 11 with a minute gap therebetween in a non-contact manner.

[0063] The foaming adhesive on the outer surface side of the foaming insulation member 43 housed and arranged together with the plurality of insertion portions 15a of the coil 15 in each slot 31 of the stator core 14 foams by heating or the like, and thus intrudes into the opening 40 on the radially inner side of the slot 31. The foaming adhesive that has intruded into the opening 40 adheres to the outer peripheral surface of the annular partition wall 37 arranged outside (radially inner side) of the opening 40. As a result, the peripheral wall main body portion 12a of the annular partition wall 37 is adhesively fixed to the foaming insulation member 43 inside the plurality of slots 31 through the opening 40 of the slot 31.

[0064] When an electric current continuously flows through the coil 15 during the operation of the rotating electric machine 1 having the above structure, the coil 15 generates heat and becomes high temperature.

[0065] At this time, the coolant 23 is introduced from the circulation circuit 25 to the first liquid chamber 21 of the rotating electric machine 1 through the introduction port 24. The coolant 23 introduced into the first liquid chamber 21 flows in the first liquid chamber 21, thereby cooling the one end side region (pull-back portion 15b) of the coil 15 exposed to the outside from the one end side of the axial direction of the stator core 14. In addition, the coolant 23 flows from the one end side to the other end side in the axial direction in the plurality of slots 31 (coolant passages 44 in the slots 31) of the stator core 14, and flows into the second liquid chamber 22. The coolant flowing in the slots 31 cools the insertion portion 15a of the coil 15 passing through the slots 31. In addition, the coolant 23 flowing into the second liquid chamber 22 cools the other end side region of the coil 15 exposed to the outside from the other end side of the axial direction of the stator core 14, and then returns to the circulation circuit 25 through the discharge port 26.

[0066] As described above, the stator 10 of the rotating electrical machine 1 is always immersed in the coolant 23 in the rotating electrical machine case 12. In this state, the coolant 23 in the rotating electrical machine case 12 is replaced by the circulation circuit 25. Therefore, the coil 15 of the stator 10 is efficiently cooled by the coolant 23.

[0067] Next, refer to Figures 3 to 6 A method for manufacturing the coil 15 wound around the stator core 14 as described above will be described.

[0068] It should be noted that in Figures 3 to 6 In the figure, the diagram is omitted for easy understanding. Figure 2 The insulating coating 42 of the coil 15 is shown. In the following description, the "width direction" of the coil 15 refers to a direction perpendicular to the vertical direction in a cross section of the coil 15 (a cross section perpendicular to the extending direction).

[0069] Figure 3 is a perspective view of a processing device 70 for forming grooves 50 on the sides s1 and s2 of the coil 15, Figure 4 It is a schematic cross-sectional view of the processing device 70.

[0070] The coil 15 has four side surfaces s1, s2, s3, and s4 that are orthogonal to the extension direction (length direction). Two side surfaces s1 and s2 are arranged to face opposite directions to each other, and the remaining two side surfaces s3 and s4 are arranged to face directions orthogonal to the side surfaces s1 and s2 and to face opposite directions to each other. The grooves 50 are respectively formed on the side surfaces s1 and s2 that face opposite directions to each other. In the present embodiment, the side surface s1 constitutes the first side surface, and the side surface s2 constitutes the second side surface. In addition, the side surfaces s3 and s4 constitute a pair of other side surfaces that face opposite directions except the first side surface and the second side surface.

[0071] As a pre-stage of forming the groove 50 on the side surfaces s1 and s2 of the coil 15, an insulating coating film 42 (see Figure 2 ) is covered on the outer surface of the wire 41 whose cross-section is substantially rectangular (see Figure 2 ), and it is pre-cut into a predetermined length for use. The cut coil 15 is installed on the Figure 3 , Figure 4 -shown processing device 70.

[0072] The processing device 70 includes: a mounting table 71 for mounting the coil 15 with the side surface s2 facing down (see Figure 4 ); a first male mold 72 for pressing and forming the groove 50 on the upper side surface s1 of the coil 15; a second male mold 73 for pressing and forming the groove 50 on the lower side surface s2 of the coil 15; and a pair of support molds 74 for clamping the left and right side surfaces s3 and s4 of the coil 15.

[0073] As shown in Figure 4 , an avoidance hole 75 extending along the extending direction of the coil 15 is formed on the mounting table 71. The avoidance hole 75 is a hole for avoiding interference with the second male mold 73, and penetrates the upper wall 71u of the mounting table 71 in the up and down direction.

[0074] The upper base of the first male mold 72 is connected to the descending motion part of a stamping device (not shown).

[0075] A pressing part 72a with a mountain-shaped cross-section is formed at the lower end of the first male mold 72. The central part in the width direction of the pressing part 72a bulges downward in an arc shape. By pressing this bulging part against the upper side surface s1 of the coil 15, a groove 50 can be formed in the central part in the width direction of the side surface s1.

[0076] The lower base of the second male mold 73 is connected to the ascending motion part of a stamping device (not shown).

[0077] A pressing part 73a with a mountain-shaped cross-section is formed at the upper end of the second male mold 73. The central part in the width direction of the pressing part 73a bulges upward in an arc shape. By pressing this bulging part against the lower side surface s2 of the coil 15, a groove 50 can be formed in the central part in the width direction of the side surface s2.

[0078] Each of the left and right support molds 74 is supported by a clamping block 77 via a spring member 76 (see Figure 4 ). The part of the support mold 74 facing the left and right side surfaces s3 and s4 of the coil 15 is a support surface 74a for clamping the coil 15. The coil 15 placed on the upper wall 71u of the mounting table 71 is clamped and fixed by the left and right support molds 74 spring-biased by the spring member 76.

[0079] Since each support die 74 is spring-biased by a spring member 76, when a large load (impact) is externally input to the coil 15 clamped by the left and right support dies 74 during processing, displacement corresponding to the load is allowed. Each support die 74 is spring-biased by the spring member 76 in such a manner that it can be displaced when the load is input.

[0080] When forming the grooves 50 on the side surfaces s1, s2 of the coil 15 using the processing device 70, the coil 15 is placed on the upper wall 71u of the placement table 71, and in this state, the support surfaces 74a of the left and right support dies 74 are pressed against the side surfaces s3, s4 of the coil 15. Thereby, the coil 15 is clamped and fixed in a state of being spring-biased by the left and right support dies 74.

[0081] When the coil 15 is thus installed in the processing device 70, the first male die 72 of the processing device 70 descends and the pressing portion 72a of the first male die 72 presses against the upper side surface s1 of the coil 15, and the second male die 73 ascends and the pressing portion 73a of the second male die 73 presses against the lower side surface s2 of the coil 15. The start timing of pressing the side surfaces s1, s2 of the coil 15 by the first male die 72 and the second male die 73 at this time may be the same, or the start timing of pressing by the second male die 73 may be slightly later than the start timing of pressing by the first male die 72.

[0082] That is, when manufacturing the coil 15 using the processing device 70, when press-forming the groove 50 on the upper side surface s1 (one of the first side surface and the second side surface) of the coil 15, the press-forming of the groove 50 on the lower side surface s2 (the other of the first side surface and the second side surface) of the coil 15 is started.

[0083] In this way, when the upper side surface s1 and the lower side surface s2 of the coil 15 are pressed by the first male die 72 and the second male die 73, a compressive load acts on the region in the cross-section of the coil 15 that is sandwiched by the pressing portion 72a of the first male die 72 and the pressing portion 73a of the second male die 73. Thereby, the region sandwiched by the pressing portion 72a of the first male die 72 and the pressing portion 73a of the second male die 73 is compressed and deformed, and thus the grooves 50 are respectively formed on the upper side surface s1 and the lower side surface s2 of the coil 15. After that, the first male die 72 is raised and the second male die 73 is lowered, thereby ending the pressing of the side surfaces s1, s2 of the coil 15. The end timing of pressing the side surfaces s1, s2 of the coil 15 by the first male die 72 and the second male die 73 at this time may be the same, or the end timing of pressing by the first male die 72 (the raising of the first male die 72) may be slightly later than the end timing of pressing by the second male die 73 (the lowering of the second male die 73).

[0084] As described above, in the method of manufacturing the coil 15 of the present embodiment, when the recess 50 is press-molded on the upper side surface s1 (one of the first side surface and the second side surface) of the coil 15, the press-molding of the recess 50 on the lower side surface s2 (the other of the first side surface and the second side surface) of the coil 15 is started. Therefore, the press-molding for forming the recess 50 on one side surface s1 and the press-molding for forming the recess 50 on the other side surface s2 are performed overlapping in time (lap). Further, at this time, the direction of the load applied to the side surface s1 for forming the recess 50 on one side and the direction of the load applied to the side surface s2 for forming the recess 50 on the other side become facing directions. Therefore, the portions with high stress concentrate in the region inside the coil 15 that linearly connects the pressing portion 72a for forming the recess 50 on one side surface s1 and the pressing portion 73a for forming the recess 50 on the other side surface s2, and the portions with high stress are difficult to spread to other portions.

[0085] Refer to Figure 5 、 Figure 6 to describe this situation in detail.

[0086] Figure 5 FIG. is a diagram showing the processing steps (A), (B), (C), (D) when press-molding one by one the side surfaces s1, s2 of the coil 15 facing in opposite directions and the internal pressure distribution of the coil 15 at this time. Figure 6 FIG. is a diagram showing the processing steps (A), (B) when press-molding both side surfaces s1, s2 of the coil 15 facing in opposite directions overlapping in time and the internal pressure distribution of the coil 15 at this time. In Figure 5 、 Figure 6 the greater the stress inside the coil 15, the thicker the concentration is shown.

[0087] In Figure 5 the comparative example shown, in the step (A), the coil 15 is placed on the placement table 71, and in the subsequent step (B), the side surface s1 on one side is press-molded from the upper side by the male mold. Thereby, the recess 50 is formed on the side surface s1 on one side. In this step (B), a pressing load acts between the pressing portion of the male mold pressed against the center in the width direction of the side surface s1 of the coil 15 and the flat upper surface of the placement table 71. As a result, in the cross section of the coil 15, as shown by the thickly concentrated portion in (B), the portion with high stress gradually spreads downward and outward in the width direction. In (B), the portion with high stress divides into two and spreads outward in the width direction of the coil 15.

[0088] In the subsequent step (C), the coil 15 is turned upside down so that the other side surface s2 faces upward, and one side surface s1 is placed on the placement table 71. In this state, stress that gradually expands in the width direction toward the side surface s2 remains in the cross section of the coil 15.

[0089] Then, in step (D), the other side surface s2 is pressed and formed from the upper side by a male mold. As a result, a groove 50 is formed on the other side surface s2. In this step (D), a pressing load acts between the pressing portion of the male mold that presses the center in the width direction of the side surface s2 of the coil 15 and the flat upper surface of the placement table 71. As a result, in the cross section of the coil 15, as shown by the portion with a high concentration in (D), the portion with a large stress gradually expands downward and outward in the width direction, and is combined with the stress remaining in the coil 15. As a result, a portion with a high stress remains in a relatively wide area in the width direction of the coil 15. That is, a large stress acts on an area that has no direct relation to the formation of the groove 50, and deformation occurs in an unnecessary portion.

[0090] In addition, during the pressing and forming processes in steps (B) and (D), since a large stress is generated in an unnecessary portion of the coil 15, the load for pressing the male mold becomes correspondingly larger.

[0091] In contrast, in Figure 6 the manufacturing method of the present embodiment shown, in step (A), the coil 15 is placed on the placement table 71, and in the subsequent step (B), the side surfaces s1 and s2 are pressed and formed from the upper side and the lower side, respectively, by male molds. That is, the pressing and forming of one side surface s1 and the pressing and forming of the other side surface s2 are overlapped in time, and the pressing and forming of one side surface s1 and the pressing and forming of the other side surface s2 are performed from opposite directions facing each other. In this step (B), a pressing load acts between the central region in the width direction of one side surface s1 of the coil 15 and the central region in the width direction of the other side surface s2. As a result, in the cross section of the coil 15, as shown by the portion with a high concentration in (B), the portion with a large stress is concentrated in a narrow area connecting the central region in the width direction of one side surface s1 and the central region in the width direction of the other side surface s2, and does not expand outward in the width direction.

[0092] After the processing of the groove 50 is completed in this way, it is difficult for deformation to occur in unnecessary portions in the cross section of the coil 15.

[0093] Note that, near the ends in the extending direction of the grooves 50 on the sides s1, s2 of the coil 15, a load is applied that causes the ends in the extending direction of the coil 15 to bend in the pressing direction. Therefore, when the grooves 50 are respectively pressed and formed on the sides s1, s2 of the coil 15 without time overlap, lengthwise bending deformation is likely to remain at the ends in the extending direction of the coil 15. However, in the manufacturing method of the coil 15 of the present embodiment, since the pressing and forming of the sides s1, s2 of the coil 15 facing in opposite directions are performed substantially simultaneously from the facing directions, almost no lengthwise bending deformation occurs at the ends in the extending direction of the coil 15.

[0094] Therefore, when the manufacturing method of the coil 15 of the present embodiment is adopted, when the grooves 50 are formed on the sides s1, s2 of the coil 15 facing in opposite directions, unnecessary deformation is difficult to occur on the coil 15. Therefore, when the manufacturing method of the coil 15 is adopted, the product quality of the coil 15 can be further improved, the input load required for processing can be reduced, and smooth processing of the coil 15 can be achieved.

[0095] In addition, during the manufacturing of the coil 15, it is preferable that at least one of the start timing of the pressing and forming of one side s1 and the other side s2 and the end timing of the pressing and forming of one side s1 and the other side s2 is made consistent. When the start timing of the pressing and forming of one side s1 and the other side s2 is made consistent, the deformation load that rapidly increases at the initial stage of pressing can be concentrated between the pressing portions 72a, 73a of the two sides s1, s2, and the situation where the highly stressed part diffuses to the surroundings can be prevented. In addition, when the end timing of the pressing and forming of one side s1 and the other side s2 is made consistent, even if there are some deformation deviations between one side s1 and the other side s2 before the end of the pressing and forming, the deformation deviations can ultimately be corrected.

[0096] Note that, more preferably, both the start timing of the pressing and forming of one side s1 and the other side s2 and the end timing of the pressing and forming of one side s1 and the other side s2 are made consistent. In this case, the deformation load that rapidly increases at the initial stage of pressing can be concentrated between the pressing portions of one side s1 and the other side s2, and the deformation deviations between one side s1 and the other side s2 can ultimately be corrected. Therefore, when this method is adopted, the processing accuracy of the grooves 50 on the sides s1, s2 of the coil 15 can be further improved.

[0097] Moreover, in the method for manufacturing the coil 15 of the present embodiment described above, when press-forming one side surface s1 and the other side surface s2 of the coil 15, the support die 74 holds the pair of the remaining other side surfaces s3 and s4. In this case, by holding the pair of the other side surfaces s3 and s4 with the support die 74, rotation of the coil 15 during press-forming can be suppressed. Therefore, when the method for manufacturing the coil 15 of the present embodiment is adopted, press-forming of the coil 15 can be performed with high precision.

[0098] In addition, in the method for manufacturing the coil 15 of the present embodiment, the support die 74 is biased by the spring member 76 so as to be displaceable when a load is input. Therefore, when this method is adopted, the impact associated with the input of a large load during press-forming can be absorbed by the function of the spring member 76.

[0099] Therefore, when this method is adopted, the grooves 50 can be formed stably and with high precision on the side surfaces s1 and s2 of the coil 15 facing in opposite directions.

[0100] It should be noted that the present invention is not limited to the above-described embodiment, and various design changes can be made without departing from its gist. For example, in the above-described embodiment, the grooves 50 formed on the side surfaces s1 and s2 of the coil 15 are recessed in an arc shape, but the shape of the grooves 50 is not limited to this shape. The grooves 50 can be, for example, a shape having corners in part such as a triangle or a quadrilateral.

[0101] In addition, in the above-described embodiment, the cross-sectional shape of the coil 15 (rotating electric machine coil) is substantially rectangular, but the cross-sectional shape of the coil 15 is not limited to being substantially rectangular. The cross-sectional shape of the coil 15 only needs to be a cross-sectional shape having a first side surface and a second side surface facing in opposite directions, and can also be an even-sided polygon other than a quadrilateral such as a hexagon or an octagon.

[0102] In addition, in the above-described embodiment, the coil 15 (coil for a rotating electric machine) having the grooves 50 is used for a part of the stator 10 of the rotating electric machine 1, but this coil 15 can also be applied to parts other than the stator 10. For example, in a rotating electric machine having a coil winding portion in the rotor portion, it can also be used for the rotor portion.

[0103] Moreover, in the above-described embodiment, the first male die 72 and the second male die 73 are moved up and down in the vertical direction to press-form the grooves 50 on the side surfaces s1 and s2 of the coil 15, but the pressing direction of the first male die 72 and the second male die 73 is not limited to the vertical direction. The pressing direction of the first male die 72 and the second male die 73 can also be, for example, the horizontal direction.

Claims

1. A method for manufacturing a coil for a rotating electric machine, wherein the coil for a rotating electric machine has a first side surface and a second side surface facing in opposite directions, and grooves along the length direction are respectively provided on the first side surface and the second side surface, wherein: The method for manufacturing a coil for a rotating electrical machine includes the step of: when the groove is press-formed on one of the first side surface and the second side surface, starting press-forming of the groove on the other of the first side surface and the second side surface.

2. The method for manufacturing a coil for a rotating electrical machine according to claim 1, wherein: make the start timing of the press molding of the first side surface and the second side surface, and Completion timing of the press molding of the first side surface and the second side surface At least one of them is consistent.

3. The method for manufacturing a coil for a rotating electrical machine according to claim 2, wherein: The press molding on the first side surface and the second side surface are started at the same timing, and the press molding on the first side surface and the second side surface are ended at the same timing.

4. The method for manufacturing a coil for a rotating electrical machine according to claim 1 or 2, wherein: When the first side surface and the second side surface are subjected to the press molding, a pair of side surfaces other than the first side surface and the second side surface and facing in opposite directions are clamped by a supporting mold.

5. The method for manufacturing a coil for a rotating electrical machine according to claim 4, wherein: The support die is urged by a spring so as to be displaceable when a load is input.

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