Method and device for manufacturing laminated iron core

Abstract

The invention provides a method and a device for manufacturing a laminated iron core, which can predict the occurrence of a welding crack and further improve the suppression of the welding crack. In a method for manufacturing a laminated iron core (1) in which a plurality of iron core pieces (7) are laminated, the laminated iron core (1) is pressed and welded in the lamination direction. The amount of compression of the laminated iron core (1) caused by the pressurization, the amount of contraction of the laminated iron core (1) in the lamination direction at the welding site, and the amount of springback of the laminated iron core (1) caused by the release of the pressurization are accumulated within the compression limit of the laminated iron core (1).

Description

Technical Field

[0001] This invention relates to a method and apparatus for manufacturing a stacked iron core having multiple iron chips stacked on top of each other. Background Technology

[0002] As an existing method for manufacturing laminated iron cores, there is the method described in Patent Document 1. This manufacturing method, for example, involves welding the laminated iron core while applying a second load below the first load to the laminated iron core obtained by applying a first load.

[0003] This welding reduces springback in the stacking direction of the laminated iron core and suppresses weld cracks.

[0004] However, this manufacturing method does not take into account the relationship between compression caused by the pressure applied to the stacked iron core during welding, shrinkage caused by cooling after welding, and springback caused by the release of pressure. Therefore, there is a limit to the suppression of weld cracks, i.e., weld fissures.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent No. 7078424 Summary of the Invention

[0008] The problem that the invention aims to solve

[0009] The problem to be solved is that there is a limit to the suppression of weld cracks in laminated iron cores.

[0010] Solution for solving the problem

[0011] The present invention provides a method for manufacturing a laminated iron core, wherein the laminated iron core comprises a plurality of iron chips, wherein the laminated iron core is pressurized and welded along the lamination direction, such that the cumulative amount of compression of the laminated iron core caused by the pressurization, the amount of shrinkage of the laminated iron core at the welded location in the lamination direction, and the amount of springback of the laminated iron core caused by the release of the pressurization are within the compression limit of the laminated iron core.

[0012] Furthermore, the present invention provides a manufacturing apparatus for a laminated iron core, comprising: a pressurizing mechanism that pressurizes a laminated iron core having multiple iron chips stacked thereon in a stacking direction; a welding mechanism that welds the pressurized laminated iron core in the stacking direction; and a control unit that controls the pressurizing mechanism to ensure that the cumulative amount of compression of the laminated iron core caused by the pressurization, the amount of contraction of the laminated iron core at the welding location in the stacking direction, and the amount of springback of the laminated iron core caused by the release of the pressurization are within the compression limit of the laminated iron core.

[0013] Invention Effects

[0014] This invention can improve the suppression of welding cracks in laminated iron cores. Attached Figure Description

[0015] Figure 1 This is a perspective view of the stacked iron core of Embodiment 1 of the present invention.

[0016] Figure 2 yes Figure 1 A plan view of the stacked iron core.

[0017] Figure 3 This is an enlarged photograph showing the welding cracks on the laminated iron core when the manufacturing method of Example 1 is not applied.

[0018] Figure 4 It means Figure 1 An enlarged photograph of the shrinkage caused by welding of the stacked iron core.

[0019] Figure 5 It means Figure 1 Enlarged photograph of the pressure applied to the unwelded parts of the stacked iron core.

[0020] Figure 6 It is a graph showing the height status of the stacked iron core, including both welded and unwelded sections.

[0021] Figure 7 It is a plan view showing the surface pressure conditions of the welded and unwelded parts.

[0022] Figure 8 It is a graph showing the relationship between the compressibility limit of the laminated iron core, the amount of compression under pressure, the amount of shrinkage caused by welding, and the amount of springback caused by the release of pressure.

[0023] Figure 9 This is a schematic diagram showing the manufacturing apparatus for the laminated iron core of Embodiment 1.

[0024] Figure 10 It means Figure 9 A schematic diagram of the manufacturing apparatus used for welding.

[0025] Figure 11 This is an enlarged side view of a part of the manufacturing apparatus of Example 2.

[0026] Figure 12 yes Figure 11 An enlarged cross-sectional view of a part of the manufacturing apparatus. Detailed Implementation

[0027] The present invention achieves the purpose of improving the suppression of weld cracks in laminated iron cores by means of a manufacturing method and apparatus that accumulates the amount of compression of the laminated iron core caused by pressure, the amount of shrinkage in the lamination direction of the laminated iron core at the welded part, and the amount of springback of the laminated iron core caused by the release of pressure within the compression limit of the laminated iron core.

[0028] That is, the manufacturing method of the laminated iron core 1 is a method for manufacturing a laminated iron core 1 having multiple iron chips 7 stacked on top of each other. In this manufacturing method, the laminated iron core 1 is welded under pressure in the stacking direction, and then the pressure is released. At this time, the cumulative amount of compression of the laminated iron core 1 caused by the pressure, the amount of shrinkage of the laminated iron core 1 in the stacking direction at the welded part, and the amount of springback of the laminated iron core 1 caused by the release of the pressure are all within the compression limit of the laminated iron core 1.

[0029] The laminated iron core 1 is welded sequentially at multiple locations in the circumferential direction. Alternatively, at the end of the sequential welding of these multiple locations, the cumulative amount of compression, shrinkage, and springback of the laminated iron core 1 is kept within the compression limit of the laminated iron core 1.

[0030] As one implementation, the applied load can also be reduced so that the cumulative amount of compression, shrinkage and springback of the laminated core 1 is within the compression limit of the laminated core 1.

[0031] As another implementation, pressure can also be applied using the pressure plate 27. In this case, the pressure position of the pressure plate 27 is fixed such that the cumulative amount of compression, shrinkage, and springback of the laminated iron core 1 is within the compression limit of the laminated iron core 1.

[0032] As another embodiment, pressure can also be applied using pressure plate 27 and push rod 33. In this case, push rod 33 follows the gap S between the laminated iron core 1 and pressure plate 27 caused by the shrinkage of the laminated iron core 1 in the lamination direction at the welding site, and together with the pressure applied by pressure plate 27, pressure is applied to the laminated iron core 1 within the gap S.

[0033] The manufacturing apparatus 15 includes a pressurizing mechanism 17, a welding mechanism 19, and a control unit 21. The pressurizing mechanism 17 applies pressure to the laminated iron core 1 in the lamination direction. The welding mechanism 19 welds the pressurized laminated iron core 1 along the lamination direction. The control unit 21 controls the load applied by the pressurizing mechanism 17 to ensure that the cumulative amount of compression, shrinkage, and springback of the laminated iron core 1 is within the compression limit of the laminated iron core 1.

[0034] The welding mechanism 19 can also perform welding sequentially at multiple locations in the circumferential direction of the laminated iron core 1. In this case, the control unit 21 can also control the load so that the cumulative amount of compression, shrinkage, and springback of the laminated iron core 1 is within the compression limit of the laminated iron core 1 at the end of the welding of the multiple locations sequentially performed on the laminated iron core 1.

[0035] In one embodiment, the control unit 21 may also reduce the load during pressurization so that the cumulative amount of compression, shrinkage and springback of the laminated core 1 is within the compression limit of the laminated core 1.

[0036] In other embodiments, the pressurizing mechanism 17 may also include a pressure plate 27. In this case, the control unit 21 may also fix the pressurizing position of the pressure plate in such a way that the cumulative amount of compression, contraction, and springback of the laminated iron core 1 is within the compression limit of the laminated iron core 1.

[0037] Alternatively, as another embodiment, the manufacturing apparatus 15 may also include a pressure plate 27, a welding mechanism 19, and a push rod 33. The push rod 33 is movably supported on the pressure plate 27 in the stacking direction and follows the gap S between the pressure plate 27 and the stacked iron core 1, and together with the pressure applied by the pressure plate 27, applies pressure to the stacked iron core 1 within the gap S.

[0038] Example 1

[0039] [Laminated iron core]

[0040] Figure 1 This is a perspective view of the stacked iron core of Embodiment 1 of the present invention. Figure 2 yes Figure 1 A plan view of the laminated iron core. Furthermore, in the following description, the stacking direction, circumferential direction, radial direction, and axial direction refer to the stacking direction, circumferential direction, radial direction, and axial direction of the laminated iron core, respectively.

[0041] Figure 1 as well as Figure 2 The laminated iron core 1 is the stator core of a rotary electric motor. This laminated iron core 1 is formed by integrally bonding multiple annular iron chips 7 made of sheet metal in a axially stacked state through multiple welded portions 5 on the outer periphery. The state of the stacked iron chips 7 before the formation of the welded portions 5 includes a state where the iron chips 7 are joined together by riveting, or a state where the iron chips 7 are not joined together by riveting, etc., as long as the iron chips 7 are stacked. The iron chips 7 are formed, for example, from electromagnetic steel sheet by punching. Alternatively, the iron chips 7 can be formed by laser melting or wire cutting instead of punching. The laminated iron core 1 can also be used as a rotor core. In this case, the welded portions can be formed on the inner periphery, outer periphery, magnet mounting holes, etc. of the rotor core.

[0042] The welded portion 5 is formed along the stacking direction. In the embodiment, for example... Figure 3 They are formed at eight circumferential locations. The number of welded portions 5 is not limited to eight and can be increased or decreased relative to eight. Each welded portion 5 is formed within a radial recess 9 on the outer periphery of the laminated iron core 1 (see reference). Figure 4 Within the recess 9, a welding protrusion 9a is provided before welding (see reference). Figure 5 The welding section 5 has a weld bead 13 formed by welding the welding protrusion 9a in a straight line along the stacking direction. In addition, the welding can be performed at any predetermined location on the stacked iron core 1, and is not limited to the location based on the recess 9 and the welding protrusion 9a.

[0043] The laminated iron core 1 is welded according to the manufacturing method of this embodiment, which suppresses welding cracks in the weld portion 5 (weld bead 13). Figure 3 This is an enlarged photograph showing the welding crack C of the laminated iron core 1 when the manufacturing method of this embodiment is not applied. The formation mechanism of this welding crack C will be explained.

[0044] [Mechanism of Weld Crack Formation]

[0045] Figure 4 It means Figure 1 An enlarged photograph of the shrinkage caused by welding of the stacked iron core. Figure 5 It means Figure 1 Enlarged photograph of the pressure applied to the unwelded parts of the stacked iron core.

[0046] When welding the laminated iron core 1, it is supported on the support fixture described later in the unwelded state, and as follows: Figure 4 as well as Figure 5 As shown, pressure is applied in the stacking direction by the pressure ring 27, which serves as the pressure plate in this embodiment. This pressure compresses and shrinks the stacked core 1 in the stacking direction. In this state, welding protrusions 9a within the recess 9 are subjected to welding such as TIG welding and laser welding along the stacking direction, forming a weld bead 13 in the welded portion 5.

[0047] The welding is performed sequentially at multiple locations in the circumferential direction, for example, eight locations. The welding at the multiple locations is performed sequentially according to the pairs of welding protrusions 9a located on both sides radially relative to the center of the laminated iron core 1. However, the welding can also be performed sequentially location by location.

[0048] In the welded portion 5, which serves as the welding point, shrinkage occurs in the lamination direction due to cooling, such as... Figure 4 As shown, in this contracted portion, the laminated core 1 shrinks in the lamination direction. Consequently, the upper surface of the laminated core 1 is separated from the pressure ring 27 by a gap S in this portion. On the other hand, in the unwelded portion, as... Figure 5As shown, the pressurized ring 27 is kept in a pressurized state in the stacking direction. Therefore, the surface pressure of the stacked iron core 1 rises due to the pressurized ring 27 at the un-welded part.

[0049] Figure 6 is a graph showing the height state of the stacked iron core 1 including the welded part and the un-welded part. Figure 7 is a plan view showing the surface pressure conditions of the pressurization of the welded part and the un-welded part.

[0050] including Figure 4 and Figure 5 the dimensional state in the stacking direction (i.e., the height state) of the stacked iron core 1 of the welded part and the un-welded part is as Figure 6 shown. In Figure 6 it shows the state when welding is carried out in eight parts, four pairs of parts in sequence, and up to the third pair of parts. In this state, the height becomes lower at each welded part, and at the last un-welded fourth pair of parts, the height is high. Figure 6 The symbols in

[0051] represent the welding sequence. The first pair of parts is 1, the second pair of parts is 2, the third pair of parts is 3, and the fourth pair of parts is 4. Figure 7 In Figure 7 the white part A is the welded part and the surface pressure is low. The dark-colored part is the un-welded part and the surface pressure is high. The cross-hatched part is the part other than the welded part and the un-welded part. There is shrinkage due to welding at the welded part A, and the surface pressure becomes lower compared to the un-welded part B. [[ID=二十七]]

[0052] Thus, as the surface pressure increases, the reduction amount (compression amount) caused by the compression during the pressurization of the stacked iron core 1 increases. Therefore, the cumulative reduction amount (shrinkage amount) caused by the shrinkage of the weld bead 13 at this part of the stacked iron core 1 gradually becomes larger as welding progresses (the reduction of the un-welded part). Moreover, it can be seen that when the value obtained by subtracting the springback amount when the pressurization of the stacked iron core 1 is released from the cumulative value of the compression amount and the shrinkage amount of the stacked iron core 1, that is, the cumulative value of the compression amount, the shrinkage amount, and the springback amount of the stacked iron core 1 exceeds the compression limit of the stacked iron core 1, welding cracks occur. The springback amount is the phenomenon that the stacked iron core 1 expands in the stacking direction when the pressurization is released, that is, the magnitude of the springback. The compression limit refers to the state where the stacked iron core 1 is compressed in the stacking direction so that the iron cores 7 are in close contact with each other, that is, the limit at which the stacked iron core 1 can be compressed.

[0053] Figure 8 is a graph showing the relationship between the compression limit of the stacked iron core, the compression amount during pressurization, the shrinkage amount caused by welding, and the springback.

[0054] In Figure 8In the diagram, the vertical axis represents the load when the pressure ring 27 applies pressure to the laminated iron core 1, and the horizontal axis represents the height displacement of the welded part.

[0055] like Figure 8 As shown, in the laminated iron core 1, when the compression amount of the laminated iron core 1 ( Figure 8 The amount of core compression), the amount of shrinkage of weld 13 at this location ( Figure 8 When the cumulative shrinkage and springback of the weld bead exceed the compression limit of the laminated iron core 1, a corresponding amount of cracking force is applied to the weld bead 13 to separate the iron chip 7. As a result, cracks are generated in the weld bead 13, leading to welding cracks.

[0056] In the manufacturing method of this embodiment, the generation of welding cracks can be anticipated, thereby improving the suppression of welding cracks.

[0057] [Manufacturing method and apparatus for laminated iron cores]

[0058] Figure 9 This is a schematic diagram of the manufacturing apparatus 15 for the laminated iron core. Figure 10 This is a schematic diagram of the manufacturing apparatus 15 used for welding.

[0059] The manufacturing method in this embodiment is implemented using manufacturing apparatus 15. However, the manufacturing method can also be implemented without using manufacturing apparatus 15. Figure 9 as well as Figure 10 As shown, the manufacturing apparatus 15 includes a pressurizing mechanism 17, a welding mechanism 19, and a control unit 21.

[0060] The pressurizing mechanism 17 pressurizes the laminated iron core 1 in the stacking direction. The pressurizing mechanism 17 includes a support clamp 23, a pressure ring 25, and a pressure ring 27 serving as a pressure plate. The support clamp 23 has a core rod 23b supporting the laminated iron core 1 on a base 23a. A pressure ring 25 is provided around the core rod 23b on the base 23a.

[0061] The pressure ring 25 abuts against and supports the lower surface of the laminated iron core 1, which is supported by the support fixture 23. The pressure ring 27 is a structure found in a stamping machine or similar device (not shown), which applies pressure to the upper surface of the laminated iron core 1 together with the pressure ring 25 on the lower surface in the lamination direction. The pressure ring 27 does not release the applied load until the welding process is completed, and it follows the rotation direction of the laminated iron core 1. Furthermore, the pressure plate is not limited to the annular pressure ring 27; any plate-shaped portion capable of applying pressure to the laminated iron core 1 is acceptable.

[0062] The pressure ring 25 and the pressure ring 27 are rotatably driven, which positions the pressurized laminated iron core 1 relative to the welding mechanism 19 in the circumferential direction.

[0063] The welding mechanism 19 welds the pressurized laminated iron core 1 along the lamination direction. The welding mechanism 19 has laser irradiation units 29 arranged on both sides of the laminated iron core 1 supported by the pressurizing mechanism 17. Thus, the laser irradiation units 29 can weld each pair of welding protrusions 9a on the laminated iron core 1 on the pressurizing mechanism 17. Furthermore, the welding mechanism 19 is not limited to laser welding and can perform other welding methods. For example, when the welding mechanism 19 performs TIG welding, a welding torch can be used instead of the laser irradiation unit 29.

[0064] The control unit 21 is a computer equipped with a CPU, ROM, RAM, etc., and has the welding program for the laminated iron core 1 installed. In addition, the welding program for the laminated iron core 1 can also be stored as a welding program for the laminated iron core 1 on a removable storage medium.

[0065] The welding program for the laminated iron core 1 enables the computer to perform welding control and pressure control functions.

[0066] The welding control function applies pressure to the stacked iron core 1 in the stacking direction by setting a load and causing the welding mechanism 19 to operate, thereby performing welding on the stacked iron core 1 in the stacking direction.

[0067] The pressure control function controls the pressure load applied by the pressure mechanism 17 to ensure that the cumulative amount of compression, shrinkage, and springback of the laminated iron core 1 is within the compression limit of the laminated iron core 1. In this embodiment, at the end of the sequential welding of multiple circumferential locations of the laminated iron core 1, for example, at the fourth pair of locations out of four pairs out of eight locations, the pressure load applied by the pressure mechanism 17 is controlled to ensure that the cumulative amount of compression, shrinkage, and springback of the laminated iron core 1 is within the compression limit of the laminated iron core 1.

[0068] In this embodiment, load control involves load reduction. This load reduction is sufficient to ensure that the cumulative compression, shrinkage, and springback of the laminated core 1 remain within its compression limit during the final welding process. This can be achieved once or multiple times during the sequential welding of multiple sections. By reducing the load applied during the sequential welding of multiple sections, the increase in the compression of the laminated core 1 corresponding to the welding process can be suppressed. Load reduction can also be performed during each welding of multiple sections.

[0069] In the manufacturing method using the manufacturing apparatus 15, when the laminated iron core 1 is pressurized and welded along the lamination direction, the pressurization is adjusted so that the cumulative amount of compression in the lamination direction caused by pressurization, the amount of contraction in the lamination direction caused by welding, and the amount of springback when the pressurization is released are within the compression limit of the laminated iron core 1.

[0070] When pressurizing the laminated iron core 1, the laminated iron core 1 is first supported on... Figure 9The laminated iron core 1 is positioned on the pressure ring 25 via the support clamp 23. For this laminated iron core 1, as... Figure 10 As shown, the laminated iron core 1 is pressurized from the upper surface with a set load using a pressure ring 27.

[0071] The load is set such that, at least initially, in this embodiment during the first pair of welds, the cumulative amount of compression, shrinkage, and springback of the laminated core 1 is within the compression limit of the laminated core 1. The amount of compression, shrinkage, and springback can be determined in advance through experiments, etc.

[0072] The first pair of welding protrusions 9a of the stacked iron core 1 on the pressurizing mechanism 17 are positioned circumferentially on the laser irradiation section 29. Then, the laser irradiation section 29 irradiates the first pair of welding protrusions 9a with laser light throughout the stacking direction. As a result, the first pair of welds is performed on the stacked iron core 1.

[0073] This welding process creates a shrinkage in the weld bead 13 towards the stacking direction. In this shrinkage portion, a gap S is created between the pressure ring 27 and the stacked core 1.

[0074] Thus, when the first pair of welds is completed, the surface pressure at the other unwelded areas increases due to the applied pressure. Consequently, the compression at the unwelded areas of the laminated core 1 increases compared to before the first pair of welds. The cumulative amount of this increased compression, the shrinkage caused by the first pair of welds, and the springback of the laminated core 1 caused by the release of pressure, as described above, is kept within the compression limit by setting the applied pressure load.

[0075] Then, the welding at the second pair of welding protrusions 9a is also carried out in a manner that accumulates within the compression limit by increasing the amount of compression, shrinkage and springback of the stacked iron core 1.

[0076] For example, before welding the second pair of welding protrusions 9a, if it is predicted that the cumulative increase in compression, shrinkage, and springback of the laminated core 1 due to this welding will exceed the compression limit, the applied load is reduced before the second pair of welding. The predicted compression, shrinkage, and springback amounts at this time are the same as those used when determining the set load, and can be obtained in advance through experiments, etc.

[0077] Alternatively, the load can be reduced by comparing the cumulative compression, shrinkage, and springback at the completion of the first pair of welds with a threshold value. Or, as long as the surface pressure required for welding can be maintained, the load can be automatically reduced based on the completion of each weld.

[0078] Automatic load reduction can be achieved, for example, by reducing the surface pressure of the laminated core 1, which is expected to increase upon completion of welding. That is, if welding is performed while applying pressure to the laminated core 1 with a constant load, the surface pressure at the welded area decreases due to the contraction of the weld bead 13, while the surface pressure at the unwelded areas becomes relatively higher. When the surface pressure increases, the compression of the laminated core 1 increases at the unwelded areas; therefore, it is sufficient to reduce this expected increase in surface pressure.

[0079] The load reduction ratio is preferably about 99% to 45% relative to the initial pressurized load of the laminated core 1. By reducing the load, it is possible to maintain, for example, the surface pressure initially applied, in the unwelded areas.

[0080] Furthermore, the pressure position of the pressure ring 27 can be fixed to a predetermined value. The pressure position is the position of the pressure ring 27 in the stacking direction of the laminated core 1. By fixing it, the increase of surface pressure at unwelded parts can be suppressed.

[0081] Subsequently, as described above, the stacked iron core 1 is pressurized and welded at the third pair and subsequent parts until the final fourth pair is welded, so that the cumulative amount of compression, shrinkage and springback of the stacked iron core 1 is within the compression limit of the stacked iron core 1.

[0082] Therefore, it is possible to suppress the cracking force acting between the iron chips 7 due to the springback of the stacked iron core 1, thereby suppressing the welding cracks of the weld bead 13.

[0083] In this embodiment, the load during pressurization is reduced by keeping the cumulative amount of compression, shrinkage, and springback of the laminated iron core 1 within the compression limit. Therefore, it is possible to suppress the increase in the amount of compression of the laminated iron core 1 corresponding to the welding process, and to more reliably suppress the welding cracks of the weld bead 13.

[0084] Example 2

[0085] Figure 11 This is an enlarged side view of a part of the manufacturing apparatus of Example 2. Figure 12 yes Figure 11 An enlarged cross-sectional view of a portion of the manufacturing apparatus. Furthermore, in Embodiment 2, the basic structure is the same as in Embodiment 1; therefore, structural parts that are the same as or correspond to those in Embodiment 1 are indicated by the same symbols, and repeated descriptions are omitted.

[0086] In Embodiment 2, the push rod 33 follows the gap S between the laminated iron core 1 and the pressure ring 27 caused by the contraction in the lamination direction of the laminated iron core 1 generated at the welding site. Thus, together with the pressure applied by the pressure ring 27, the laminated iron core 1 is pressurized within the gap S using the push rod 33. Therefore, the manufacturing apparatus 15 of this embodiment includes, in addition to the pressure applying mechanism 17, the welding mechanism 19, and the control unit 21, a surface pressure holding mechanism 31. Furthermore, the following of the gap S is limited to following the gap S in the lamination direction, and is not limited to following it in the circumferential direction.

[0087] like Figure 11 as well as Figure 12 As shown, the surface pressure holding mechanism 31 includes a push rod 33 and a compression spring 35. Alternatively, a hydraulic cylinder, a pneumatic cylinder, a solenoid, or the like can be used instead of the compression spring 35.

[0088] The push rod 33 is movably supported on the pressure ring 27 in the stacking direction. In this embodiment, the push rod 33 is an integral shaft-shaped component with a spring seat 33a. Furthermore, the shape of the push rod 33 is not particularly limited as long as it can follow the gap S.

[0089] The push rod 33 protrudes towards the laminated iron core 1 through the through hole 27a of the pressure ring 27. The through hole 27a communicates with the spring receiving hole 27b. A spring seat 33a is disposed in the spring receiving hole 27b. A compression spring 35 is disposed in the spring receiving hole 27b. The compression spring 35 is disposed between the nut 37, which is threaded into the upper side of the spring receiving hole 27b, and the spring seat 33a.

[0090] The surface pressure holding mechanism 31 is configured to correspond to one or more, or all, of a plurality of welding positions performed sequentially. In this embodiment, the surface pressure holding mechanism 31 corresponds to all welding positions.

[0091] At the welded area, when a gap S caused by contraction is generated in the weld bead 13, the compression spring 35 of the surface pressure holding mechanism 31 pushes the push rod 33 toward the laminated iron core 1 according to the gap S. Thus, the push rod 33 follows the gap S and applies pressure to the laminated iron core 1 within the gap S.

[0092] Therefore, in this embodiment, the surface pressure generated by the pressure applied at the welding site can be maintained by the surface pressure holding mechanism 31 according to the amount of shrinkage in the stacking direction of the laminated core 1, thereby suppressing the rise in surface pressure of the entire laminated core 1. Furthermore, the surface pressure held by the surface pressure holding mechanism 31 can be maintained as long as the cumulative amount of compression, shrinkage, and springback of the laminated core 1 at the welding site is within the compression limit. Within this limit, the surface pressure at the unwelded site can also rise.

[0093] Thus, in this embodiment 2, the surface pressure of the laminated iron core 1 is maintained, thereby suppressing the increase in the amount of compression corresponding to the welding and reliably improving the suppression of welding cracks in the weld bead 13.

[0094] Furthermore, Example 2 can achieve the same effect as Example 1. Alternatively, Example 2 can be combined with Example 1.

[0095] Symbol Explanation

[0096] 1—Laminated iron core, 7—Iron chip, 15—Manufacturing apparatus for laminated iron core, 17—Pressure applying mechanism, 19—Welding mechanism, 21—Control unit, 31—Surface pressure holding mechanism.

Claims

1. A method for manufacturing a laminated iron core, wherein the laminated iron core comprises multiple laminated iron chips, characterized in that... The laminated iron core is pressurized and welded along the lamination direction. The cumulative amount of compression of the laminated core caused by the pressurization, the amount of contraction of the laminated core in the stacking direction at the welded location, and the amount of springback of the laminated core caused by the release of the pressurization is within the compression limit of the laminated core.

2. The method for manufacturing a laminated iron core according to claim 1, characterized in that, The welding is performed sequentially at multiple circumferential locations on the laminated iron core. At the end of the sequential welding of the multiple locations, the accumulation of the compression, shrinkage, and springback is made within the compression limit of the laminated iron core.

3. The method for manufacturing a laminated iron core according to claim 1 or 2, characterized in that, Reduce the load during pressurization so that the cumulative amount of compression, contraction, and springback is within the compression limit of the laminated core.

4. The method for manufacturing a laminated iron core according to claim 1 or 2, characterized in that, The pressurization is achieved through a pressure plate. The pressure plate is fixed in a fixed position so that the cumulative amount of compression, contraction, and springback is within the compression limit of the laminated iron core.

5. The method for manufacturing a laminated iron core according to claim 1 or 2, characterized in that, The pressurization is achieved through a pressure plate. The push rod follows the gap between the laminated iron core and the pressure plate caused by the contraction of the laminated iron core in the lamination direction at the welding site, and together with the pressure applied by the pressure plate, pressurizes the laminated iron core within the gap.

6. A method for manufacturing a laminated iron core, wherein the laminated iron core comprises multiple laminated iron chips, characterized in that... The laminated iron core is pressurized and welded along the lamination direction. The welding is performed sequentially at multiple circumferential locations on the laminated iron core. The load during the pressurization is reduced during the welding of the multiple parts performed in sequence.

7. A method for manufacturing a laminated iron core, wherein the laminated iron core comprises multiple laminated iron chips, characterized in that... The laminated iron core is pressurized and welded along the lamination direction using a pressure plate. The welding is performed sequentially at multiple circumferential locations on the laminated iron core. The push rod follows the gap between the laminated iron core and the pressure plate caused by the contraction of the laminated iron core in the lamination direction at the welding site, and together with the pressure applied by the pressure plate, pressurizes the laminated iron core within the gap.

8. An apparatus for manufacturing a stacked iron core, characterized in that, have: The pressurizing mechanism applies pressure to a stacked iron core containing multiple iron chips along the stacking direction; A welding mechanism that welds the pressurized laminated iron core along the lamination direction; and The control unit controls the load applied by the pressurizing mechanism so that the accumulation of the compression of the laminated core caused by the pressurization, the shrinkage of the laminated core in the lamination direction at the welded portion, and the springback of the laminated core caused by the release of the pressurization is within the compression limit of the laminated core.

9. The apparatus for manufacturing a laminated iron core according to claim 8, characterized in that, The welding mechanism sequentially performs the welding at multiple locations along the circumference of the laminated iron core. The control unit controls the load so that, at the end of the sequential welding of the plurality of locations, the accumulation of the compression, the shrinkage, and the springback is within the compression limit of the laminated iron core.

10. The apparatus for manufacturing a laminated iron core according to claim 8 or 9, characterized in that, The control unit reduces the load during pressurization so that the accumulation of the compression, contraction, and springback is within the compression limit of the laminated iron core.

11. The apparatus for manufacturing a laminated iron core according to claim 8 or 9, characterized in that, The pressurizing mechanism includes a pressure plate for applying the pressurization. The control unit fixes the pressure position of the pressure plate so that the accumulation of the compression, the contraction, and the springback is within the compression limit of the laminated iron core.

12. A manufacturing apparatus for a laminated iron core, characterized in that, have: The pressure plate applies pressure to the stacked iron core containing multiple iron chips along the stacking direction; A welding mechanism that welds the pressurized laminated iron core along the lamination direction, and sequentially performs the welding at multiple locations in the circumferential direction; and A push rod, which is movably supported on the pressure plate in the stacking direction, follows the gap between the stacked iron core and the pressure plate caused by the contraction of the stacked iron core in the stacking direction at the welding location, and applies pressure to the stacked iron core within the gap together with the pressure applied by the pressure plate.

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