Laminated core and method for manufacturing laminated core

Abstract

A laminated core (10) comprises a laminate (20) constituted by a plurality of laminated core pieces (40). The laminate (20) has a flow path (26) through which a refrigerant flows. The boundary (44) between the core pieces (40) adjacent to each other is closed by a seal part (40a) which is a part of the core piece (40) that makes contact with the boundary (44) in at least a part of the inside of the flow path (26).

Description

Laminated iron core and method of manufacturing the same

[0001] The disclosed embodiments relate to laminated cores and methods for manufacturing laminated cores.

[0002] For example, there is a known motor in which a flow path for circulating a coolant is formed inside the laminated body that makes up the rotor. This flow path allows the magnets located inside the rotor to be cooled, thereby preventing irreversible demagnetization due to high temperatures during motor operation.

[0003] Japanese Patent Application Laid-Open No. 2018-186604

[0004] However, with conventional technology, the coolant flowing through the flow paths within the laminates could leak from the boundaries between adjacent core pieces in the lamination direction, reducing the amount of coolant available for cooling, which could reduce the rotor's cooling performance and therefore reduce motor performance.

[0005] One aspect of the embodiment has been made in consideration of the above, and aims to provide a laminated core and a method for manufacturing a laminated core that can prevent refrigerant from leaking from flow paths within the laminate.

[0006] A laminated core according to one aspect of the present invention includes a laminate body made up of a plurality of stacked core pieces. The laminate body has a flow path through which a coolant flows. The boundary between adjacent core pieces is sealed, at least in part, inside the flow path with a seal portion that is a part of the core piece that contacts the boundary.

[0007] Furthermore, a manufacturing method for a laminated core according to one aspect of the embodiment includes the steps of forming a hole, forming a seal, forming core pieces, and forming a laminate. The hole forming step involves punching a strip-shaped metal plate to form a hole that becomes part of a flow path through which a refrigerant flows. The seal forming step involves deforming the periphery of the hole to form a seal. The core piece forming step involves punching the metal plate to form the core pieces. The laminate forming step involves stacking a plurality of the core pieces to form the laminate. The laminate forming step involves sealing the boundary between adjacent core pieces with the seal in at least a portion of the interior of the flow path.

[0008] According to one aspect of the embodiment, it is possible to suppress leakage of the refrigerant from the flow paths in the laminate. Note that the effects described here are not necessarily limited to those described herein, and may be any of the effects described in the present disclosure.

[0009] FIG. 1 is a plan view showing an example of a rotor according to an embodiment. FIG. 2 is a cross-sectional view taken along line A-A in FIG. 1 . FIG. 3 is a schematic diagram showing an example of a manufacturing apparatus for a laminated core according to an embodiment. FIG. 4 is a flowchart showing an example of the procedure of each manufacturing process performed by the manufacturing apparatus for a laminated core according to an embodiment. FIG. 5 is an enlarged cross-sectional view showing an example of the configuration of a laminate according to an embodiment. FIG. 6A is an enlarged cross-sectional view showing an example of another configuration of a seal portion according to an embodiment. FIG. 6B is a diagram for explaining an example of the arrangement of a seal portion according to an embodiment. FIG. 6C is a diagram for explaining another example of the arrangement of a seal portion according to an embodiment. FIG. 6D is a diagram for explaining another example of the arrangement of a seal portion according to an embodiment. FIG. 6E is a diagram for explaining another example of the arrangement of a seal portion according to an embodiment. FIG. 6F is a diagram for explaining another example of the arrangement of a seal portion according to an embodiment. FIG. 6G is a diagram for explaining another example of the arrangement of a seal portion according to an embodiment. FIG. 6H is a diagram for explaining another example of the arrangement of a seal portion according to an embodiment. FIG. 6I is a diagram for explaining another example of the arrangement of a seal portion according to an embodiment. FIG. 6J is a diagram for explaining another example of the arrangement of a seal portion according to an embodiment. Fig. 7A is an enlarged cross-sectional view showing another example of the configuration of the laminated body according to the embodiment. Fig. 7B is an enlarged cross-sectional view showing another example of the configuration of the laminated body according to the embodiment. Fig. 8 is a perspective view showing an example of the configuration of a laminated core according to another embodiment. Fig. 9 is a cross-sectional view taken along the line B-B in Fig. 8.

[0010] Hereinafter, a laminated core and a method for manufacturing a laminated core disclosed in the present application will be described with reference to the accompanying drawings. Note that the present disclosure is not limited to the following embodiments.

[0011] It should also be noted that the drawings are schematic and that the dimensional relationships and ratios of elements may differ from reality. Furthermore, the drawings may contain parts whose dimensional relationships and ratios differ from one another.

[0012] <Overall Configuration of Rotor> First, the overall configuration of a rotor 1 using a laminated core 10 according to an embodiment will be described with reference to Figures 1 and 2. Figure 1 is a plan view showing an example of a rotor 1 according to an embodiment, and Figure 2 is a cross-sectional view taken along line A-A in Figure 1.

[0013] As shown in FIGS. 1 and 2 , a rotor 1 according to the embodiment includes a laminated core 10 and a rotor shaft 12 .

[0014] The laminated core 10 also includes a lamination body 20 and a plurality of permanent magnets 30. As shown in Fig. 2, the lamination body 20 is made up of a plurality of laminated core pieces 40. The core pieces 40 are plate-like bodies obtained by punching out a strip-shaped electromagnetic steel sheet MS (see Fig. 3) into a predetermined shape.

[0015] 1 , the laminate 20 has a central hole 22 and a plurality of insertion holes 24. The central hole 22 is located in the center in a plan view and passes through the laminate 20 in the axial direction. The plurality of insertion holes 24 are located at intervals along the circumferential direction and pass through the laminate 20 in the axial direction.

[0016] In the following description, the radial direction, axial direction, and circumferential direction of the laminated core 10 are defined. Here, the "radial direction" is a direction perpendicular to the rotation axis of the rotor 1 in which the laminated core 10 is used, the "axial direction" is a direction that coincides with the axial direction of the rotation axis of the rotor 1, and the "circumferential direction" is a direction that coincides with the rotation direction of the rotor 1.

[0017] The plurality of core pieces 40 constituting the laminate 20 include, for example, a plurality of first core pieces 41, a plurality of second core pieces 42, and a plurality of third core pieces 43, as shown in FIG.

[0018] The multiple first core segments 41 are located in the axial center of the laminate 20. The multiple second core segments 42 sandwich the multiple first core segments 41 from both sides in the axial direction in the laminate 20. The multiple third core segments 43 sandwich the multiple second core segments 42 from both sides in the axial direction in the laminate 20.

[0019] In the laminated core 10 according to the embodiment, the adjacent core pieces 40 may be fastened together by various known methods. For example, the adjacent core pieces 40 may be joined together using a crimped portion, an adhesive, or a resin material, or may be joined together by welding.

[0020] Alternatively, the laminate 20 may be obtained by providing temporary crimps to the core pieces 40, fastening a plurality of core pieces 40 together via the temporary crimps, and then removing the temporary crimps from the laminate 20. This "temporary crimp" refers to a crimp that is used to temporarily unite a plurality of core pieces 40 together and that is removed in the process of manufacturing the product (laminated core 10 or rotor).

[0021] The permanent magnets 30 are inserted into the insertion holes 24, respectively, and fixed to the laminate 20 via a filler 32. The filler 32 is preferably, for example, a thermosetting epoxy resin.

[0022] As shown in Figure 1, the laminate 20 according to the embodiment has, for example, multiple pairs (ten pairs in Figure 1) of insertion holes 24 adjacent to each other in the circumferential direction. Each pair of insertion holes 24 has an elongated cross-sectional shape, and the closer they are to each other, the more inwardly they are located. The permanent magnets 30 have a rectangular cross-sectional shape that is long in the longitudinal direction of the cross section of the insertion holes 24.

[0023] As shown in FIG. 2 , the rotor shaft 12 is inserted through the central hole 22 of the laminated core 10 .

[0024] Furthermore, a cooling flow path is provided inside the laminated core 10 to allow a refrigerant (such as oil) to flow therethrough to cool the permanent magnets 30. This cooling flow path includes a flow path 12a located inside the rotor shaft 12 and a flow path 26 located inside the laminated body 20 and connected to the flow path 12a.

[0025] The flow paths 26 also include axial flow paths 27 and radial flow paths 28. The axial flow paths 27 extend along the axial direction (the left-right direction in FIG. 2 ) of the stack 20. The radial flow paths 28 connect the axial flow paths 27 and the central hole 22.

[0026] The axial flow passages 27 are formed in all of the plurality of first core laminations 41, second core laminations 42 and third core laminations 43 that constitute the laminate 20, and pass through the laminate 20 in the axial direction.

[0027] The radial flow passages 28 are formed in the first core fragments 41 and the second core fragments 42 that are located in the axial center of the plurality of first core fragments 41, second core fragments 42, and third core fragments 43 that make up the laminate 20. The radial flow passages 28 have slits 28a and through holes 28b.

[0028] The slits 28a are connected to the central hole 22 and extend radially. The slits 28a are also connected to the flow passages 12a via communication holes 12b that penetrate the peripheral wall of the rotor shaft 12. The through holes 28b branch into two from the outer periphery of the slits 28a, extend radially outward, and connect to the axial flow passages 27.

[0029] <Manufacturing Apparatus> Next, a manufacturing apparatus 100 for the laminated core 10 according to the embodiment will be described with reference to Fig. 3. Fig. 3 is a schematic diagram showing an example of the manufacturing apparatus 100 for the laminated core 10 according to the embodiment. The manufacturing apparatus 100 according to the embodiment is configured to manufacture a laminate 20 of core pieces 40 (see Fig. 2) from a strip-shaped electromagnetic steel sheet MS, and to manufacture the laminated core 10 (see Fig. 2) from the laminate 20. The electromagnetic steel sheet MS is an example of a metal sheet.

[0030] As shown in FIG. 3, the manufacturing apparatus 100 includes, for example, a punching device 200, a magnet inserting device 300, a preheating device 400, a resin injecting device 500, and a controller Ctr (control unit).

[0031] The punching device 200 includes an uncoiler 210, a feeding device 220, and a press processing device 230. The uncoiler 210 is configured to rotatably hold a coil material 211. The coil material 211 is an electromagnetic steel sheet MS wound in a coil shape (spiral shape).

[0032] The feed-out device 220 includes a pair of rollers 221, 222 that sandwich the electromagnetic steel sheet MS from above and below. The pair of rollers 221, 222 are configured to rotate and stop based on instruction signals from the controller Ctr, and to intermittently feed the electromagnetic steel sheet MS sequentially toward the press processing device 230. In other words, the pair of rollers 221, 222 function as a conveying means for conveying the electromagnetic steel sheet MS.

[0033] The stamping device 230 is configured to operate based on instruction signals from the controller Ctr. The stamping device 230 has, for example, a function of sequentially stamping the electromagnetic steel sheets MS intermittently fed by the feed device 220 to form the core pieces 40 (see FIG. 2 ), and a function of sequentially stacking the stamped core pieces 40 to manufacture the laminate 20. The stamping performed by the stamping device 230 includes, for example, punching and half-punching.

[0034] The magnet insertion device 300 operates based on instructions from the controller Ctr and has the function of inserting permanent magnets 30 (see FIG. 1) into the insertion holes 24 (see FIG. 1) of the laminate 20 transported from the punching device 200 by a conveyor Cv or the like.

[0035] The preheating device 400 operates based on instructions from the controller Ctr, and has the function of heating the laminate 20 transferred from the magnet insertion device 300 .

[0036] The resin injection device 500 operates based on instructions from the controller Ctr, and has the function of injecting the filler material 32 (see FIG. 1) into the insertion holes 24 of the laminate 20 transferred from the preheating device 400 .

[0037] The controller Ctr is configured to generate instruction signals for operating each device in the manufacturing apparatus 100 based on, for example, a program recorded on a recording medium (not shown) or an operation input from an operator. The controller Ctr is configured to transmit these instruction signals to each device in the manufacturing apparatus 100.

[0038] <Manufacturing Process> Next, the manufacturing process of the laminated core 10 according to the embodiment will be described with reference to Fig. 4. Fig. 4 is a flowchart showing an example of the procedure of each manufacturing process executed by the manufacturing apparatus 100 for the laminated core 10 according to the embodiment.

[0039] As shown in FIG. 4, the controller Ctr (see FIG. 3) first controls the feeding device 220 (see FIG. 3) and the like to feed the electromagnetic steel sheet MS forward by a predetermined pitch in the forward feed direction within the press processing device 230 (see FIG. 3) (step S101).

[0040] In parallel with step S101, a press working step (step S102) and a core piece forming step (step S103) are carried out in this order.

[0041] In the press working step (step S102), the controller Ctr controls the press working device 230 to lower the upper die and clamp the electromagnetic steel sheet MS between the upper die and the lower die, thereby performing press working on the electromagnetic steel sheet MS.

[0042] In this press working step, for example, the controller Ctr punches out the electromagnetic steel sheet MS to form a hole that will become part of the flow path 26 (see FIG. 2) through which the refrigerant flows. In addition, in this press working step, for example, the controller Ctr performs half-punching on at least a part of the periphery of the hole to form a seal portion 40a (see FIG. 5).

[0043] In the core piece forming process (step S103), the controller Ctr controls the press processing device 130 to lower the upper mold so that the electromagnetic steel sheet MS is clamped between the upper and lower molds, and the electromagnetic steel sheet MS is punched out to form the core piece 40 (see Figure 2).

[0044] Next, the controller Ctr controls the stamping device 130 to stack the core pieces 40 to form the laminate 20 (see FIG. 2) (step S104). Note that in this laminate formation process, the core pieces 40 adjacent to each other in the stacking direction may be fastened to each other by caulking, adhesive, or the like.

[0045] Next, the controller Ctr controls the magnet insertion device 300 to insert the permanent magnets 30 (see FIG. 2) into the insertion holes 24 (see FIG. 2) of the laminate 20 (step S105).

[0046] Next, the controller Ctr controls the preheating device 400 to preheat the laminate 20 into which the permanent magnets 30 have been inserted (step S106). The preheating device 400 uses, for example, heated gas or a heater to heat the laminate 20 to a temperature suitable for filling with the filler 32 (see FIG. 2).

[0047] Next, the controller Ctr controls the resin injection device 500 to inject the filler 32 into the insertion holes 24 into which the permanent magnets 30 have been inserted in the preheated laminate 20 (step S107). This completes the series of manufacturing steps.

[0048] <Configuration of Flow Channel> Next, the detailed configuration of the flow channel 26 provided in the laminate 20 according to the embodiment will be described with reference to Fig. 5 to Fig. 7B. Fig. 5 is an enlarged cross-sectional view showing an example of the configuration of the laminate 20 according to the embodiment.

[0049] As shown in Figure 5, in the laminate 20 of the embodiment, the boundary 44 located between adjacent core pieces 40 is blocked inside the flow path 26 by a sealing portion 40a, which is a part of the core piece 40 that contacts the boundary 44.

[0050] 5 , the boundary 44 between adjacent first core pieces 41 is closed by a seal portion 40a that is part of the first core piece 41 inside the flow path 26. Furthermore, the boundary 44 between adjacent second core pieces 42 is closed by a seal portion 40a that is part of the second core piece 42 inside the flow path 26.

[0051] Furthermore, the boundary 44 between adjacent third core pieces 43 is closed within the flow path 26 by a seal portion 40a that is part of the third core piece 43. Furthermore, the boundary 44 between adjacent first core pieces 41 and second core pieces 42 is closed within the flow path 26 by a seal portion 40a that is part of the first core piece 41 or the second core piece 42.

[0052] Furthermore, the boundary 44 between the adjacent second core piece 42 and third core piece 43 is closed by a seal portion 40 a that is part of the second core piece 42 or the third core piece 43 inside the axial flow passage 27 .

[0053] This makes it possible to prevent the refrigerant flowing through the flow paths 26 in the laminate 20 from leaking from the boundaries 44 between adjacent core pieces 40. Therefore, according to the embodiment, the cooling performance of the permanent magnets 30 can be maintained well, and therefore the performance of the motor in which the rotor 1 is used can be maintained well.

[0054] Furthermore, in the embodiment, since the cooling performance of the permanent magnet 30 can be maintained well, there is no need to provide a more powerful mechanism (such as an oil pump) to supply the refrigerant, which contributes to the miniaturization of the entire motor.

[0055] In addition, in an embodiment, as shown in Figure 5, the sealing portion 40a may be formed by half-punching (pressing down) the periphery of the hole portion that forms the flow path 26 in the iron core piece 40 using a press processing device 230 (see Figure 3).

[0056] This allows the seal portion 40a to be formed as part of the manufacturing process of the core pieces 40. Therefore, according to the embodiment, refrigerant leakage can be more easily suppressed than in the case where the boundaries 44 between adjacent core pieces 40 are sealed with a separate sealant or the like.

[0057] In the present disclosure, the term "half-punching" refers to a process in which press working is performed to a thickness less than the thickness of the magnetic steel sheet MS, without completely punching out the sheet.

[0058] Furthermore, the present disclosure is not limited to the case where the sealing portion 40a is formed by half-punching the periphery of the hole. For example, as shown in Fig. 6A, the sealing portion 40a may be formed by bending the periphery of the hole that defines the flow path 26 in the core piece 40. Fig. 6A is an enlarged cross-sectional view showing an example of another configuration of the sealing portion 40a according to the embodiment.

[0059] This also allows the seal portion 40 a to close the boundary 44 between the adjacent core pieces 40 , thereby preventing the refrigerant flowing through the flow path 26 from leaking from the boundary 44 .

[0060] Furthermore, in the embodiment, the seal portion 40a may be provided only in a part of the flow path 26. This reduces the residual stress in the stack 20 that occurs due to processing for providing the seal portion 40a compared to when the seal portion 40a is provided in the entire flow path 26. Therefore, according to the embodiment, deformation of the stack 20 can be suppressed.

[0061] Furthermore, in the embodiment, the seal portion 40 a may function as a crimp that fastens adjacent core pieces 40 together. This allows the boundary 44 to be firmly sealed by the seal portion 40 a, and the seal portion 40 a, which also functions as a crimp, reduces the gap between adjacent core pieces 40, thereby improving the space factor of the laminate 20.

[0062] Therefore, according to the embodiment, it is possible to prevent the coolant flowing through the flow passage 26 from leaking from the boundary 44 and the gap between the adjacent core pieces 40 .

[0063] In addition, when the sealing portion 40a is to function as a crimp, as shown in Figure 5, it is preferable that the surface 40a1 of the sealing portion 40a opposite the surface facing the flow path 26 and the side surface 40b of the iron core piece 40 that contacts this surface are both along the axial direction (i.e., approximately perpendicular to the radial direction).

[0064] As a result, even if a force is applied in a direction that moves adjacent core pieces 40 apart, a sufficient frictional force acts between the contacting surfaces 40a1 and 40b, thereby preventing adjacent core pieces 40 from separating from each other.

[0065] Furthermore, in the embodiment, the sealing portion 40a functions as a crimp, which reduces the effort required to fasten adjacent core pieces 40 together using a separate crimp, adhesive, or the like in the process of forming the laminate 20 (step S104 in FIG. 4 ), thereby simplifying the manufacturing process of the laminated core 10.

[0066] 6B is a diagram illustrating an example of the arrangement of the seal portion 40 a according to the embodiment. Note that, Figures 6B to 6E show the arrangement of the seal portion 40 a when the axial flow path 27 of the flow path 26 is viewed from the axial direction.

[0067] 6B , the seal portion 40 a according to the embodiment may be located on both the radial and circumferential sides of the flow path 26. That is, the seal portion 40 a according to the embodiment may be located around the entire circumference of the flow path 26 when viewed from the axial direction.

[0068] As a result, the boundary 44 is tightly closed by the seal portion 40 a, and leakage of the refrigerant flowing through the flow path 26 from the boundary 44 can be further suppressed.

[0069] In addition, in the embodiment, as shown in FIG. 6B, the sealing portion 40a is arranged so that the thickness is uniform along the inner wall of the flow path 26, thereby preventing the sealing performance of the sealing portion 40a from becoming uneven.

[0070] The arrangement of the seal portion 40a according to the embodiment is not limited to the example shown in Fig. 6B. Figs. 6C to 6E are diagrams illustrating other examples of the arrangement of the seal portion 40a according to the embodiment.

[0071] 6C , the seal portion 40a according to the embodiment may be located only on the radial side of the flow path 26. This makes it possible to prevent the refrigerant from leaking to the radial side of the flow path 26 (particularly the radially outer side), thereby preventing the refrigerant from leaking into the gap between the rotor 1 and the stator located radially outward.

[0072] Therefore, according to the embodiment, an increase in drag loss of the rotor 1 can be suppressed, and the performance of the motor in which the rotor 1 is used can be maintained at a good level.

[0073] Furthermore, the seal portion 40a according to the embodiment may be located only on the side of the flow path 26 where the rotor 1 faces the stator (in this case, the radially outer side), out of both radial sides of the flow path 26. This makes it possible to prevent refrigerant from leaking into the gap between the rotor 1 and the stator, which is located radially outward.

[0074] Therefore, according to the embodiment, an increase in drag loss of the rotor 1 can be suppressed, and the performance of the motor in which the rotor 1 is used can be maintained at a good level.

[0075] 6D , the seal portion 40 a according to the embodiment may be located only on the circumferential side of the flow path 26. This also makes it possible to prevent the refrigerant flowing through the flow path 26 from leaking from the boundary 44.

[0076] 6C and 6D , by providing the seal portion 40 a only in a part of the flow path 26, the residual stress in the laminate 20 caused by processing to provide the seal portion 40 a is reduced compared to when the seal portion 40 a is provided around the entire periphery. Therefore, according to the embodiment, deformation of the laminate 20 can be suppressed.

[0077] 6E, in an embodiment, the sealing portion 40a may be arranged so that the thickness is uniform along the inner wall of the substantially circular flow path 26 around the entire circumference when viewed in the axial direction. In other words, the example of Fig. 6E is a configuration in which the flow path 26 is formed in the center of a so-called round flat caulking.

[0078] In this way, by making the flow paths 26 and the seal portions 40a substantially circular in plan view, it is possible to reduce the area occupied by the flow paths 26 and the seal portions 40a in the laminate body 20. Therefore, according to the embodiment, it is possible to increase the degree of freedom in designing the laminated core 10.

[0079] In addition, in an embodiment, as shown in FIG. 6F, the sealing portion 40a may be arranged so that the thickness is uniform along the inner wall of the polygonal (e.g., pentagonal) flow path 26 around the entire circumference when viewed in the axial direction.

[0080] In this way, by making the flow path 26 and the seal portion 40a polygonal in plan view, it is possible to increase the surface area of ​​the flow path 26. Therefore, according to the embodiment, it is possible to improve the cooling performance of the permanent magnet 30 (see FIG. 1), and therefore it is possible to improve the performance of the motor in which the rotor 1 (see FIG. 1) is used.

[0081] In the example of Figure 6F, an example is shown in which the flow path 26 and the seal portion 40a are pentagonal in plan view, but the present disclosure is not limited to such an example, and the flow path 26 and the seal portion 40a may be triangular, quadrangular, or polygonal with more than one side.

[0082] In addition, in an embodiment, as shown in Figure 6G, the sealing portion 40a may be arranged so that the thickness is uniform along the inner wall of the flow path 26 around the entire circumference of the flow path 26, which has a complex shape (e.g., a star shape), when viewed in the axial direction.

[0083] In this way, by forming the flow passage 26 and the seal portion 40a in a complex shape in plan view, it is possible to increase the surface area of ​​the flow passage 26. Therefore, according to the embodiment, it is possible to improve the cooling performance of the permanent magnet 30 (see FIG. 1), and therefore it is possible to improve the performance of the motor in which the rotor 1 (see FIG. 1) is used.

[0084] In the example of Figure 6G, an example is shown in which the flow path 26 and the seal portion 40a are star-shaped in a planar view, but the present disclosure is not limited to such an example, and the flow path 26 and the seal portion 40a may have a complex shape other than a star shape.

[0085] 6A to 6G, the seal portion 40a according to the embodiment is not limited to being disposed so as to have a uniform thickness along the inner wall of the flow path 26, and the shape of the flow path 26 in a plan view and the shape of the seal portion 40a in a plan view do not have to correspond to each other. For example, as shown in FIG. 6H, the shape of the flow path 26 in a plan view and the shape of the seal portion 40a in a plan view may be completely different.

[0086] In the present disclosure, for example, as shown in Fig. 6I, the flow path 26 may be substantially circular in plan view, while the seal portion 40a may have a complex shape (for example, a star shape). In the present disclosure, for example, as shown in Fig. 6J, the flow path 26 may be polygonal in plan view (for example, a pentagon), while the seal portion 40a may be substantially circular.

[0087] In the present disclosure, for example, in a plan view, the flow path 26 may be rectangular, while the seal portion 40a may be circular or elliptical. In the present disclosure, for example, in a plan view, the flow path 26 may be circular or elliptical, while the seal portion 40a may be rectangular.

[0088] 7A is an enlarged cross-sectional view showing another example of the configuration of the laminate 20 according to the embodiment. As shown in Fig. 7A, even at a boundary 44 facing the radial flow passage 28 and where the third core piece 43 is located below the second core piece 42, the boundary 44 may be closed by a seal portion 40a formed on the second core piece 42.

[0089] In this case, if left as is, the seal portion 40a of the second core piece 42 will interfere with the third core piece 43 below, so it is advisable to provide a recess 40c in the portion of the third core piece 43 corresponding to the seal portion 40a.

[0090] This makes it possible to prevent the coolant flowing through the radial flow passages 28 from leaking from the boundary 44 where the third core piece 43 is located below the second core piece 42 .

[0091] 7B is an enlarged cross-sectional view showing another example of the configuration of the laminate 20 according to the embodiment. As shown in Fig. 7B, even at a boundary 44 facing the radial flow passage 28 and where the second core piece 42 is located below the third core piece 43, the boundary 44 may be closed by a seal portion 40a formed on the third core piece 43.

[0092] In this case, a recess 40d may be formed by half-punching the portion of the third core piece 43 corresponding to the end of the second core piece 42, and a seal portion 40a may be formed below the recess 40d.

[0093] This makes it possible to prevent the coolant flowing through the radial flow passages 28 from leaking from the boundary 44 where the second core piece 42 is located below the third core piece 43 .

[0094] Another embodiment Next, a laminated core 50 according to another embodiment will be described with reference to Fig. 8 and Fig. 9. Fig. 8 is a perspective view showing an example of the configuration of a laminated core 50 according to another embodiment, and Fig. 9 is a cross-sectional view taken along line B-B in Fig. 8.

[0095] The laminated core 50 according to another embodiment is, for example, a stator laminated core, and is a part of a stator. The stator is formed by attaching a winding to the laminated core 50. A motor is formed by combining the stator with a rotor.

[0096] The laminated core 50 has a lamination body 51. The lamination body 51 is composed of a plurality of laminated core pieces 60. The core pieces 60 are plate-like bodies obtained by punching out a strip-shaped electromagnetic steel sheet MS (see FIG. 3) into a predetermined shape.

[0097] 8, a laminate 51 according to another embodiment has a cylindrical shape. That is, a through-hole 51a (center hole) extending along the central axis Ax is provided in the center of the laminate 51. A rotor can be placed inside the through-hole 51a.

[0098] The laminate 51 includes a yoke portion 52 and a plurality of teeth 53. The yoke portion 52 has an annular shape and extends to surround the central axis Ax. The radial width, inner diameter, outer diameter, and thickness of the yoke portion 52 can each be set to various values ​​depending on the application and performance of the motor.

[0099] Each tooth 53 extends radially of the yoke portion 52 from the inner edge of the yoke portion 52 toward the central axis Ax. That is, each tooth 53 protrudes from the inner edge of the yoke portion 52 toward the central axis Ax.

[0100] The teeth 53 are arranged at approximately equal intervals in the circumferential direction of the yoke 52. Slots 51b are defined between adjacent teeth 53 and function as spaces for arranging windings (not shown).

[0101] In the laminated core 50 according to another embodiment, the adjacent core pieces 60 may be fastened together by various known methods. For example, the adjacent core pieces 60 may be joined together using a crimped portion, an adhesive, or a resin material, or may be joined together by welding.

[0102] Alternatively, the laminate 51 may be obtained by providing temporary crimps on the core pieces 60, fastening a plurality of core pieces 60 together via the temporary crimps to obtain the laminate 51, and then removing the temporary crimps from the laminate 51. This "temporary crimp" refers to a crimp that is used to temporarily unite a plurality of core pieces 60 together and that is removed in the process of manufacturing the product (laminated core 50 or stator).

[0103] Here, in another embodiment, a plurality of flow paths 51c through which a coolant (e.g., oil) for cooling the stator flows are provided in the laminate 51. The flow paths 51c, for example, axially penetrate the interior of the yoke portion 52. The plurality of flow paths 51c are also positioned, for example, side by side along the circumferential direction of the yoke portion 52.

[0104] Furthermore, openings 51d connected to one or more flow paths 51c are formed on the side of the laminate 51. The openings 51d function as, for example, an inlet or outlet for the coolant flowing through the flow paths 51c.

[0105] 9, in a laminate 51 according to another embodiment, a boundary 61 located between adjacent core pieces 60 is blocked inside a flow path 51c by a sealing portion 60a that is a part of the core piece 60 that contacts the boundary 61. Fig. 9 is a cross-sectional view taken along line B-B in Fig. 8, and shows the internal configuration of the flow path 51c.

[0106] This makes it possible to prevent the refrigerant flowing through the flow paths 51c in the laminate 51 from leaking from the boundaries 61 between adjacent core pieces 60. Therefore, according to another embodiment, it is possible to prevent the stator formed by the laminated core 50 from excessively increasing in temperature, thereby maintaining good performance of the motor in which such a stator is used.

[0107] In another embodiment, as shown in Figure 9, the sealing portion 60a may be formed by half-punching the periphery of the hole portion that forms the flow path 51c in the iron core piece 60 using a press processing device 230 (see Figure 3).

[0108] This allows the seal portion 60a to be formed as part of the manufacturing process of the core pieces 60. Therefore, according to another embodiment, refrigerant leakage can be more easily suppressed than in the case where the boundaries 61 between adjacent core pieces 60 are sealed with a separate sealant or the like.

[0109] In another embodiment, the seal portion 60a may function as a crimp that fastens adjacent core pieces 60 together. This allows the boundary 61 to be tightly closed by the seal portion 60a, further preventing the refrigerant flowing through the flow path 51c from leaking from the boundary 61.

[0110] In another embodiment, the sealing portion 60a functions as a crimp, which reduces the effort required to fasten adjacent core pieces 60 together using a separate crimp, adhesive, or the like in the process of forming the laminated body 51 (step S104 in FIG. 4 ). This simplifies the manufacturing process of the laminated core 50.

[0111] Furthermore, the seal portion 60a according to another embodiment may be located on both the radial and circumferential sides of the flow path 51c. That is, the seal portion 60a according to another embodiment may be located around the entire circumference of the flow path 51c when viewed in the axial direction.

[0112] As a result, the boundary 61 is tightly closed by the seal portion 60a, and leakage of the refrigerant flowing through the flow path 51c from the boundary 61 can be further suppressed.

[0113] In another embodiment, the seal portion 60a may be located only on the radial side of the flow path 51c, which prevents the refrigerant from leaking radially outward from the flow path 51c (particularly, the radially inner side), thereby preventing the refrigerant from leaking into the gap between the stator and the rotor located radially inside.

[0114] Therefore, according to another embodiment, an increase in the drag loss of the rotor can be suppressed, and the performance of the motor in which the stator is used can be maintained at a good level.

[0115] In another embodiment, the seal portion 60a may be located only on the radially inner side of the flow path 51c, where the stator faces the rotor, thereby preventing refrigerant from leaking into the gap between the stator and the rotor, which is located radially inner.

[0116] Therefore, according to another embodiment, an increase in the drag loss of the rotor can be suppressed, and the performance of the motor in which the stator is used can be maintained at a good level.

[0117] Furthermore, in another embodiment, the seal portion 60a may be located only on the circumferential side of the flow path 51c. This also makes it possible to prevent the refrigerant flowing through the flow path 51c from leaking from the boundary 61.

[0118] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications are possible without departing from the spirit of the present invention. For example, in the above-described embodiments, examples have been shown in which the sealing portions 40 a, 60 a are provided in the flow paths 26, 51 c of the laminated cores 10, 50 used in inner rotor type motors, but the present disclosure is not limited to such examples.

[0119] For example, the sealing portion of the present disclosure may be provided in the flow passages of a laminated core used in an outer rotor motor, which also prevents refrigerant from leaking from the flow passages within the laminations that make up the stator or rotor.

[0120] Further advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described above. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.

[0121] The present technology can also be configured as follows. (1) A laminated core including a laminate composed of a plurality of stacked core pieces, the laminate having a flow path through which a refrigerant flows, and a boundary between adjacent core pieces, at least in part of the interior of the flow path, being closed by a seal portion that is a part of the core piece that contacts the boundary. (2) The laminated core according to (1), in which the seal portion functions as a crimp that fastens the adjacent core pieces together. (3) The laminated core according to (1) or (2), in which the seal portion is located on a radial side of the flow path. (4) The laminated core according to (3), in which the laminate is part of a rotor, and the seal portion is located on a side of the rotor facing a stator. (5) The laminated core according to (3), in which the laminate is part of a stator, and the seal portion is located on a side of the stator facing the rotor. (6) The laminated core according to any one of (1) to (5), wherein the seal portion is located on a circumferential side of the flow path. (7) A method for manufacturing a laminated core, comprising: a step of punching a strip-shaped metal plate to form a hole portion that becomes part of the flow path through which a refrigerant flows; a step of deforming the periphery of the hole portion to form a seal portion; a step of punching the metal plate to form a core piece; and a step of stacking a plurality of the core pieces to form a laminate, wherein the step of forming the laminate includes closing the boundary between adjacent core pieces with the seal portion in at least a part of the interior of the flow path. (8) The method for manufacturing a laminated core according to (7), wherein the step of forming the seal portion forms the seal portion by pressing down the periphery of the hole portion. (9) The method for manufacturing a laminated core according to (7), wherein the step of forming the seal portion forms the seal portion by bending the periphery of the hole portion.

[0122] REFERENCE SIGNS LIST 10 Laminated core 20 Laminated body 26 Flow path 40 Core piece 40a Sealing portion 44 Boundary 50 Laminated core 51 Laminated body 51c Flow path 60 Core piece 60a Sealing portion 61 Boundary MS Electromagnetic steel sheet (an example of a metal sheet)

Claims

1. A laminated core comprising a laminate composed of a plurality of stacked core pieces, the laminate having a flow path through which a refrigerant flows, and the boundary between adjacent core pieces is sealed, in at least a portion of the interior of the flow path, by a sealing portion that is a part of the core piece that contacts the boundary.

2. The laminated core according to claim 1, wherein the sealing portion functions as a crimp to fasten adjacent core pieces together.

3. A laminated core according to claim 1 or 2, wherein the sealing portion is located on a radial side of the flow path.

4. The laminated core according to claim 3, wherein the laminations are part of a rotor, and the seal portion is located on the side of the rotor facing a stator.

5. The laminated core according to claim 3, wherein the laminations are part of a stator, and the seal portion is located on the side of the stator facing a rotor.

6. A laminated core according to claim 1 or 2, wherein the sealing portion is located on the circumferential side of the flow path.

7. A method for manufacturing a laminated core, comprising: a step of punching a strip-shaped metal plate to form a hole that becomes part of a flow path through which a refrigerant flows; a step of deforming the periphery of the hole to form a seal portion; a step of punching the metal plate to form an iron core piece; and a step of stacking a plurality of the iron core pieces to form a laminate, wherein the step of forming the laminate seals the boundary between adjacent iron core pieces with the seal portion in at least a portion of the interior of the flow path.

8. The method for manufacturing a laminated core according to claim 7, wherein the step of forming the seal portion includes pressing down on the periphery of the hole portion to form the seal portion.

9. The method for manufacturing a laminated core according to claim 7, wherein the step of forming the seal portion comprises bending the periphery of the hole portion to form the seal portion.