Laminated core manufacturing method

Abstract

The present invention provides a laminated core manufacturing method capable of suppressing deformation of a laminated core. In a manufacturing method of a laminated core 3 in which a plurality of core pieces 7 are laminated, the plurality of core pieces 7 are laminated to form a core piece laminate 19 having a plurality of slots 11 in the circumferential direction, and insulation paper 21 extending in the axial direction is arranged in each of the plurality of slots 11 of the core piece laminate 19 to maintain the laminated state of the plurality of core pieces 7 of the core piece laminate 19.

Description

Manufacturing method of laminated core

[0001] The present invention relates to a method for manufacturing a laminated core in which a plurality of core pieces are laminated.

[0002] A conventional method for manufacturing a laminated core, as described in Patent Document 1, involves forming a plurality of blocks by laminating a plurality of electromagnetic steel sheets and joining them by crimping (fastening), and then stacking the formed blocks and welding them together to obtain a laminated core.

[0003] However, with this manufacturing method for laminated cores, the electromagnetic steel sheets become electrically and magnetically conductive at the crimped parts (fastened parts) and welded parts, which could have a negative impact on the efficiency of rotating electric machines using the finished laminated cores.

[0004] Japanese Patent Application Laid-Open No. 2021-97493

[0005] The problem to be solved is that there is a possibility that the efficiency of a rotating electrical machine using a laminated core may be adversely affected.

[0006] The present invention provides a method for manufacturing a laminated core in which a plurality of core pieces are stacked, which method includes stacking the plurality of core pieces to form a core piece laminate having a plurality of slots in the circumferential direction, and placing insulating paper extending axially in each of the plurality of slots in the core piece laminate to maintain the stacked state of the plurality of core pieces in the core piece laminate.

[0007] The present invention can suppress adverse effects on the efficiency of a rotating electrical machine using a laminated core.

[0008] FIG. 1 is a perspective view showing a stator according to an embodiment of the present invention. FIG. 2 is a perspective view showing only the laminated core of the stator of FIG. 1. FIG. 3 is a plan view showing the laminated core of FIG. 2. FIG. 4 is a perspective view showing core pieces used in the laminated core of FIG. 1. FIG. 5(A) is a schematic perspective view showing core pieces and a jig in a manufacturing method of a laminated core according to an embodiment of the present invention, and FIG. 5(B) is a schematic perspective view showing a jig according to a modified example. FIG. 6 is a schematic perspective view showing a core piece laminate formed by stacking core pieces on the jig of FIG. 5(A). FIG. 7 is a schematic perspective view showing the insertion of insulating paper into the core piece laminate of FIG. 6. FIG. 8 is a schematic perspective view showing the state in which insulating paper has been inserted into the core piece laminate of FIG. 6. FIGS. 9(A) to 9(C) show details of the insulating paper of FIG. 7, where FIG. 9(A) is a plan view, FIG. 9(B) is a front view, FIG. 9(C) is a side view, and FIG. 9(D) is a schematic diagram showing the cross-sectional structure. Fig. 10 is an enlarged plan view showing a slot into which insulating paper has been inserted of the core piece laminate of Fig. 8. Fig. 11 is a schematic perspective view showing a state in which a slot piece is being removed from the core piece laminate of Fig. 8. Fig. 12 is a schematic perspective view showing a state in which insulating paper has been inserted into the slot of the core piece laminate of Fig. 11 from which the slot piece has been removed.

[0009] In one embodiment, a method for manufacturing a laminated core 3 involves stacking a plurality of core pieces 7 to form a core piece laminate 19 having a plurality of slots 11 in the circumferential direction. Insulating paper 21 is placed in each of the slots 11 of the core piece laminate 19 in the axial direction to maintain the stacked state of the core pieces 7 in the core piece laminate 19.

[0010] In this manufacturing method, after the insulating paper 21 is placed in all of the plurality of slots 11, the coils 5 may be assembled into the slots 11 to integrate the plurality of core pieces 7.

[0011] Before arranging the insulating paper 21, a positioning member 27 may be arranged in the axial direction in the slot 11 of the core piece laminate 19. In this case, the insulating paper 21 is arranged in the empty slot 11 of the core piece laminate 19 where the positioning member 27 is not arranged.

[0012] In this manufacturing method, the positioning member 27 may be removed from the slot 11 after at least one piece of insulating paper 21 has been placed.

[0013] In this case, before removing the positioning member 27 from the slot 11, it is preferable to place insulating paper 21 in the empty slot 11 of the core piece laminate 19 in which the positioning member 27 is not placed and which is circumferentially adjacent to the slot 11 of the core piece laminate 19 in which the positioning member 27 is inserted.

[0014] Before removing the positioning members 27 from the slots 11 , the insulating paper 21 may be inserted into all of the empty slots 11 of the core piece laminate 19 in which no positioning members 27 are placed.

[0015] The positioning members 27 may be inserted into two or more slots 11, respectively.

[0016] The insulating paper 21 may be fitted to the inner periphery of the slot 11 and may have a closed cross-sectional shape.

[0017] [Laminated core] Fig. 1 is a perspective view showing a stator according to an embodiment of the present invention. Fig. 2 is a perspective view showing only the laminated core of the stator of Fig. 1. Fig. 3 is a plan view showing the laminated core of Fig. 2. Fig. 4 is a perspective view showing a core piece used in the laminated core of Fig. 1. In the following description, the lamination direction, circumferential direction, radial direction, and axial direction mean the lamination direction, circumferential direction, radial direction, and axial direction of the laminated core, respectively.

[0018] 1, a stator 1 is provided in cooperation with a rotor (not shown) to constitute a rotating electrical machine. The stator 1 includes a laminated core 3 and a coil 5.

[0019] The laminated core 3 is formed by stacking core pieces 7 made of a plurality of electromagnetic steel sheets, silicon steel sheets, or the like. An insulating coating (not shown) is formed on the surfaces of the core pieces 7. The thickness of the core pieces 7 is, for example, 0.15 mm to 0.40 mm. This laminated core 3 is a non-integrated core in which the core pieces 7 are not joined to each other by crimping (fastening), welding, or the like, but are integrated by assembling the insulating paper 21 and the coil 5. Each core piece 7 of the laminated core 3 is formed in an annular shape, and a plurality of slots 9 are provided circumferentially on the inner circumference.

[0020] Each slot 9 is in phase with the slot 9 of an axially adjacent core piece 7 to form a slot 11 that communicates in the axial direction of the laminated core 3. The slot 9 opens radially at the inner periphery of the core piece 7 and extends radially outward.

[0021] In this embodiment, the slots 9 are formed in a rectangular shape that is long in the radial direction in a plan view. The openings 9a of the slots 9 are defined by protrusions 15 that extend circumferentially from the tips of the teeth 13 between the slots 9. The width of the openings 9a is narrower than the width of other parts of the slots 9. The protrusions 15 have inclined portions 15a that are configured so that the radial dimension gradually decreases circumferentially toward the openings 9a (see FIG. 10 ). Note that the protrusions 15 may be omitted.

[0022] The coil 5 is assembled to the laminated core 3 in a wave-wound shape having multiple layers in the radial direction. The coil 5 is made up of multiple coil segments 17. However, the coil 5 may also be made by winding a wire around the laminated core 3.

[0023] Each coil segment 17 is formed by bending, for example, a rectangular wire with a rectangular cross section into a U-shape, e.g., a hairpin shape. The multiple coil segments 17 are arranged in a circular ring shape along the circumferential direction and in multiple rows in the radial direction around the laminated core 3. The multiple legs 17a of the multiple coil segments 17 are inserted into each slot 11 of the laminated core 3 from one axial side (the lower side in Figure 1 ) while being aligned radially. The legs 17a inserted into each slot 11 protrude axially from the end of the other axial side (the upper side in Figure 1 ) of the laminated core 3.

[0024] The protruding portions of the legs 17a are bent radially and circumferentially, and the bent coil 5 holds the core pieces 7 of the laminated core 3 together. Ends 17aa of adjacent legs 17a in the radial direction are welded together.

[0025] [Manufacturing Method of Laminated Core] Fig. 5(A) is a schematic perspective view showing the core pieces 7 and a jig in the manufacturing method of the laminated core 3 according to the embodiment of the present invention, and Fig. 5(B) is a schematic perspective view showing a jig according to a modified example. Fig. 6 is a schematic perspective view showing a core piece laminate formed by stacking the core pieces on the jig of Fig. 5(A). Note that Fig. 6 only shows some of the slots 11. The same applies to Fig. 7 described below.

[0026] In the manufacturing method of this embodiment, a plurality of core laminations 7 are stacked to form a core lamination body 19 having a plurality of slots 11 in the circumferential direction. Insulating paper 21 is placed in the axial direction in each of the plurality of slots 11 of the core lamination body 19 to maintain the stacked state of the plurality of core laminations 7 in the core lamination body 19 (see FIG. 12 ).

[0027] 5A, the core pieces 7 are first stacked in the axial direction on a jig 23. The jig 23 includes a base 25 and a slot piece 27.

[0028] The base 25 is formed in a plate shape on which the core pieces 7 can be placed. The slot pieces 27 are positioning members in this embodiment, and are rod-shaped bodies that are erected in the axial direction from four points around the circumference of the base 25. The slot pieces 27 are provided so as to be detachable in the axial direction from the base 25. For example, the ends of the slot pieces 27 are inserted into holes provided in the base 25.

[0029] The slot piece 27 can also be removed by moving it radially inward relative to the base 25. The base 25 has a recess 25a formed by reducing the thickness of the base 25. As shown in Fig. 5(B) , the base 25 may have a groove 25b formed in a circumferential shape by reducing the thickness of the base 25 instead of the recess 25a.

[0030] Each slot piece 27 has a cross-sectional shape that allows it to be inserted into the slot portion 9 of the core piece 7. In this embodiment, the slot piece 27 has a rectangular cross section that corresponds to the rectangular shape of the portion of the slot portion 9 excluding the opening 9a.

[0031] The slot pieces 27 may have other cross-sectional shapes, such as a circular cross-section that contacts the inner periphery of the slot portion 9. Also, the base 25 may be omitted and only the slot pieces 27 may be used. Furthermore, the number of slot pieces 27 does not need to be four, and may be one to three or five or more, but two or more is preferable.

[0032] When stacking the core pieces 7, the slot pieces 27 of the jig 23 are inserted into the slot portions 9 of the core pieces 7, while the core pieces 7 are lowered relative to the jig 23. This process is repeated to stack a predetermined number of core pieces 7, thereby forming the core piece stack 19 shown in FIG.

[0033] The core piece laminate 19 in Fig. 6 has the same configuration as the laminated core 3 shown in Fig. 2 and has a plurality of slots 11 on the inner periphery. A slot piece 27 is disposed in some of the plurality of slots 11 (four slots 11 in this embodiment). The tapered tip of the disposed slot piece 27 protrudes upward from the core piece laminate 19.

[0034] In this state, the core pieces 7 of the core piece laminate 19 are not joined together, and the multiple core pieces 7 are positioned by the jig 23 with their phases aligned. The phase refers to the position in the circumferential direction (rotational direction). In the core piece laminate 19, multiple slots 11 are formed in the circumferential direction by the slot portions 9 of the core pieces 7 of the same phase communicating in the axial direction. The core pieces 7 are insulated from each other by the insulating coating on their surfaces.

[0035] It is also possible to form the core piece laminate 19 by laminating the core pieces 7 without using the jig 23 .

[0036] Fig. 7 is a schematic perspective view showing the insertion of insulating paper 21 into the core piece laminate 19 of Fig. 6. Fig. 8 is a schematic perspective view showing the state in which insulating paper 21 has been inserted into the core piece laminate 19 of Fig. 6.

[0037] 7 , the insulating paper 21 is inserted axially into the slot 11 of the core piece laminate 19. The insulating paper 21 may be inserted in any direction as long as it can be placed in the slot 11. For example, if the tooth portion 13 does not have a protrusion 15, the insulating paper 21 can be placed in the slot 11 from the radially inner side.

[0038] The insulating paper 21 is inserted into the empty slots 11 of the core piece laminate 19 where no slot pieces 27 are arranged. Note that the insulating paper 21 is used to prevent electrical leakage, etc., and is therefore ultimately inserted into all of the slots 11.

[0039] In this embodiment, as shown in Figure 8, insulating paper 21 is inserted into all empty slots 11 in which no slot pieces 27 are placed. However, as will be described later, insulating paper 21 may be inserted only into some empty slots 11 in which no slot pieces 27 are placed, as long as the stacked state of the multiple core pieces 7 can be maintained even in the absence of the slot pieces 27. "Maintaining" here means that the shape of the multiple core pieces 7 is maintained without collapsing when other insulating paper 21 is inserted.

[0040] When inserting insulating paper 21 only into some of the empty slots 11 in which no slot pieces 27 are arranged, it is preferable to insert insulating paper 21 at least into the empty slots 11 in which no slot pieces 27 are arranged that are circumferentially adjacent to the slot 11 in which the slot pieces 27 are inserted, in order to maintain the positioning state of the slot pieces 27.

[0041] 9(A) to 9(D) show details of the insulating paper 21 in Fig. 7, with Fig. 9(A) being a plan view, Fig. 9(B) being a front view, Fig. 9(C) being a side view, and Fig. 9(D) being a schematic diagram showing the cross-sectional structure. Fig. 10 is an enlarged plan view showing the slot 11 into which the insulating paper 21 of the core piece laminate 19 in Fig. 8 has been inserted.

[0042] Any suitable insulating paper can be used for the insulating paper 21. In this embodiment, the insulating paper 21 is a composite material having a cross-sectional structure in which an insulating paper base material 29 is sandwiched between insulating paper materials 31. The insulating paper 21 has a thickness of 130 μm to 400 μm, a longitudinal tensile strength of 90 to 110 MPa, and a transverse tensile strength of 65 to 105 MPa. All tensile strengths are measured at room temperature.

[0043] The insulating paper base material 29 is made of a resin such as PEN (polyethylene naphthalate), although this is not a particular limitation. The insulating paper base material 29 has a thickness of, for example, 50 to 200 μm. The paper material 31 is made of, for example, aramid paper, although this is not a particular limitation. The paper materials 31 on both sides of the insulating paper base material 29 have the same thickness, for example, 50 to 80 μm, but may have different thicknesses. The insulating paper base material 29 and the paper material 31 are bonded together with an appropriate adhesive, such as an acrylic adhesive.

[0044] The insulating paper 21 is folded into a cylindrical shape having a closed cross-sectional shape that fits into the inner periphery of the slot 11. The folded end portions 21a overlap each other. In this embodiment, the closed cross-sectional shape is a rectangular frame. The folded cross-sectional shape of the insulating paper 21 can be set arbitrarily as long as it can maintain the stacked state of the multiple core laminations 7. For example, the end portions 21a may not overlap, but may be open toward the radial opening 9a of the slot 11.

[0045] Each side of the rectangular frame of the insulating paper 21 contacts the inner periphery of the slot 11 in a plan view. The sides of the insulating paper 21 straddle the opening 11a of the slot 11 in the circumferential direction. This insulating paper 21 defines an insertion space into which the leg portions 17a of the coil segments 17 are inserted. The openings 11a are formed by the openings 9a of the slot portions 9 of the same phase of the multiple core laminations 7 communicating in the axial direction.

[0046] In the axial direction, the ends of the insulating paper 21 protrude from both ends of the core piece laminate 19 across the entire area of ​​the slot 11. Note that the protrusion of the insulating paper 21 from the lower end of the core piece laminate 19 (the end that contacts the base 25 of the jig 23) is permitted by the recess 25a of the base 25. In the modified example of Figure 5 (B) , the protrusion of the insulating paper 21 from the lower end of the core piece laminate 19 is permitted by the groove 25b. In this modified example, the core piece laminate 19 can be supported on both radial sides of the groove 25b, so that the core pieces 7 can be prevented from being turned up at the lower end of the core piece laminate 19 when the insulating paper 21 is inserted.

[0047] Fig. 11 is a schematic perspective view of the core piece laminate 19 of Fig. 8 when the slot pieces 27 are removed. Fig. 12 is a schematic perspective view of the core piece laminate 19 of Fig. 11 with the slot pieces 27 removed and insulating paper 21 inserted into the slots 11.

[0048] 11, the slot piece 27 is pulled out from the slot 11 of the core piece laminate 19. The slot piece 27 is pulled out by holding the base 25 of the jig 23 and gripping the tip of the slot piece 27 protruding from the end 21b of the core piece laminate 19 and pulling it upward.

[0049] The slot piece 27 can be removed after inserting at least one insulating paper 21. In this case, the number of insulating papers 21 to be inserted is set within a range that can maintain the stacked state of the multiple core pieces 7. As described above, the slot piece 27 can also be removed by moving it radially inward relative to the base 25.

[0050] The insulating paper 21 is inserted into the empty slots 11 from which the slot pieces 27 have been removed. The insulating paper 21 is inserted into each empty slot 11 after all the slot pieces 27 have been removed, but it may also be inserted after each slot piece 27 has been removed.

[0051] 12, the core piece laminate 19 with the insulating paper 21 inserted into all of the slots 11 is placed on the base 25 of the jig 23. In this state, the shape of the core piece laminate 19 is maintained by the insulating paper 21 to the extent that the core pieces 7 do not collapse during transportation or other processes.

[0052] Next, as shown in FIG. 1, the coils 5 are assembled into the slots 11 to integrate the plurality of core laminations 7 of the core lamination body 19.

[0053] That is, the legs 17a of the multiple coil segments 17 are inserted into the slots 11 of the core piece laminate 19, and the portions of the legs 17a that protrude from the core piece laminate 19 are bent in the radial direction and the circumferential direction. In this way, the multiple core pieces 7 are fastened together to form an integrated laminated core 3. Thereafter, the ends 17aa of the legs 17a that are adjacent in the radial direction are welded together to manufacture the stator 1.

[0054] As described above, in the manufacturing method of the laminated core 3 of this embodiment, the laminated state of the plurality of core laminations 7 of the core lamination body 19 is maintained by utilizing the insulating paper 21 without using crimping (fastening), welding, or the like. This prevents electrical and magnetic conduction between the core laminations 7 of the manufactured laminated core 3. Therefore, in this embodiment, it is possible to prevent adverse effects on the efficiency of a rotating electrical machine using the laminated core 3.

[0055] Furthermore, in this embodiment, the insulating paper 21 is used to maintain the laminated state of the core pieces 7 of the core piece laminate 19 without using crimping (fastening) or welding, etc. This simplifies the manufacturing process and also prevents deformation of the laminated core 3.

[0056] In this embodiment, after insulating paper 21 is inserted into all of the slots 11, coils 5 are assembled into the slots 11 to integrate the core pieces 7 of the core piece laminate 19, thereby obtaining the laminated core 3. Therefore, this embodiment can more reliably suppress deformation of the laminated core 3 and simplify the manufacturing process.

[0057] In this embodiment, slot pieces 27 are placed in some of the slots 11 of the core piece laminate 19 before the insulating paper 21 is inserted. Therefore, the insulating paper 21 can be easily placed in the slots 11 of the core piece laminate 19 with the core pieces 7 of the core piece laminate 19 positioned.

[0058] In this case, the insulating paper 21 is inserted at least into an empty slot 11 circumferentially adjacent to the slot 11 into which the slot piece 27 is inserted, and which does not have a slot piece 27, and then the slot piece 27 is removed. This makes it easier to maintain the positioning of the multiple core pieces 7 by the slot piece 27.

[0059] In this embodiment, the insulating paper 21 is inserted into all of the empty slots 11 of the core piece laminate 19 where no slot pieces 27 are arranged before the slot pieces 27 are removed from the slots 11. Therefore, in this embodiment, the positioning of the multiple core pieces 7 by the slot pieces 27 can be more reliably maintained.

[0060] When the slot pieces 27 are inserted into two or more slots 11, the positioning state of the core pieces 7 can be stably maintained.

[0061] The insulating paper 21 has a closed cross-sectional shape that fits into the inner periphery of the slot 11, thereby improving mechanical strength and more reliably maintaining the positioning of the multiple core pieces 7 by the slot pieces 27.

[0062] The insulating paper 21 is a composite material in which an insulating paper base material 29 is sandwiched between insulating paper materials 31. This improves the mechanical strength, and the positioning of the multiple core pieces 7 by the slot pieces 27 can be more reliably maintained.

[0063] Since the insulating paper base material 29 is made of a resin such as PEN, it improves the mechanical strength of the insulating paper 21 and more reliably maintains the positioning of the multiple core pieces 7 by the slot pieces 27 .

[0064] 3 Laminated core 7 Core piece 11 Slot 19 Core piece laminate 21 Insulating paper 23 Jig 27 Slot piece (positioning member) 29 Insulating paper base material 31 Paper material

Claims

1. A method for manufacturing a laminated core in which a plurality of core pieces are laminated, the method comprising: laminating the plurality of core pieces to form a core piece laminate having a plurality of slots in the circumferential direction; and disposing insulating paper extending in the axial direction in each of the plurality of slots of the core piece laminate to maintain the laminated state of the plurality of core pieces of the core piece laminate.

2. The method for manufacturing a laminated core according to claim 1, wherein after disposing the insulating paper in all of the slots, a coil is assembled in the slots to integrate the plurality of core pieces of the core piece laminate.

3. The method for manufacturing a laminated core according to claim 1, wherein before disposing the insulating paper, positioning members are disposed in the slots of the core piece laminate in the axial direction, and the insulating paper is disposed in the slots of the core piece laminate where the positioning members are not disposed.

4. The method for manufacturing a laminated core according to claim 3, wherein after disposing the insulating paper in the empty slots of the core piece laminate where the adjacent positioning members in the circumferential direction are not disposed in the slots where the positioning members are disposed, the positioning members are removed from the slots.

5. The method for manufacturing a laminated core according to claim 4, wherein the insulating paper is disposed in all of the empty slots of the core piece laminate where the positioning members are not disposed before the positioning members are removed from the slots.

6. The method for manufacturing a laminated core according to any one of claims 3 to 5, wherein the positioning members are disposed in two or more slots respectively.

7. The method for manufacturing a laminated core according to any one of claims 1 to 5, wherein the insulating paper has a closed cross-sectional shape that fits on the inner circumference of the slots.

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