Method for manufacturing laminated iron core and apparatus for manufacturing laminated iron core

Abstract

To provide a manufacturing method of a laminated core and a manufacturing device of the laminated core, capable of suppressing occurrence of arc discharge between a block core and a positioning member.SOLUTION: A manufacturing method for a laminated core is a method for manufacturing a laminated core including a laminated body formed by laminating a plurality of punched members, a plurality of through holes extending along a lamination direction of the laminated body, and a welding portion formed by welding at least a part of the laminated body in the lamination direction. The manufacturing method includes: arranging positioning members on the through holes of the laminated body; placing the laminate body on a lower side plate; placing an upper side plate above the laminated body; and welding the welding portion of the laminated body with a welding torch while the laminated body is sandwiched between the upper side plate and the lower side plate after the above steps. A concave groove is formed in the positioning member. The concave groove is located in a portion of the positioning member corresponding to a boundary between the laminated body and at least one of the upper side plate and the lower side plate.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] The present disclosure relates to a method for manufacturing a laminated core and a manufacturing apparatus for a laminated core.

Background Art

[0002] Patent Document 1 discloses a method for manufacturing a stator laminated core, including obtaining a block core by laminating a plurality of plates punched from electromagnetic steel sheets, placing a plurality of block cores on a jig while inserting a positioning member into a through-hole provided in an ear portion of the block core, and welding the ear portions along the lamination direction of the plurality of block cores.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When welding these block cores along the lamination direction of the plurality of block cores, unintentional arc discharge may occur in the gap between the block core and the positioning member. As a result, an unintentional region of the block core or the positioning member may melt, which may affect the appearance and performance of the laminated core or the function of the positioning member.

[0005] Therefore, the present disclosure describes a method for manufacturing a laminated core and a manufacturing apparatus for a laminated core that can suppress the occurrence of arc discharge between a block core and a positioning member.

Means for Solving the Problems

[0006] An example of a method for manufacturing a laminated core is a method for manufacturing a laminated core comprising a laminate formed by stacking a plurality of punched members, a plurality of through holes extending along the stacking direction of the laminate, and a welded portion formed by welding at least a part of the laminate in the stacking direction, the method comprising: placing a positioning member in the through holes of the laminate; placing the laminate on a lower plate; placing an upper plate above the laminate; placing a positioning member; placing the laminate on a lower plate; and, after placing the upper plate above the laminate, welding the welded portion with a welding torch while the laminate is sandwiched between the lower and upper plates. A groove is formed in the positioning member. The groove is located in the part of the positioning member corresponding to the boundary between at least one of the upper plate and the lower plate and the laminate.

[0007] An example of a laminated core manufacturing apparatus includes a lower plate configured to support a laminate of multiple punched members, a positioning member configured to position the laminate relative to the lower plate by being placed in a through hole extending along the lamination direction of the laminate, an upper plate configured to be placed above the laminate, and a welding torch configured to weld a welded portion provided on the laminate while the laminate is sandwiched between the lower and upper plates. A groove is formed in the positioning member. The groove is located in the part of the positioning member corresponding to the boundary between at least one of the upper and lower plates and the laminate. In this case, the same effects as in Example 1 can be obtained. [Effects of the Invention]

[0008] According to the method for manufacturing a laminated iron core and the apparatus for manufacturing a laminated iron core described herein, it is possible to suppress the occurrence of arc discharge between the block core and the positioning member. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a perspective view showing an example of a stator laminated core. [Figure 2]Figure 2 is an exploded perspective view of the laminated structure that makes up the stator laminated core of Figure 1. [Figure 3] Figure 3 is a schematic diagram showing an example of a manufacturing apparatus for laminated iron cores. [Figure 4] Figure 4 is a schematic perspective view showing an example of a welding jig. [Figure 5] Figure 5 is a schematic cross-sectional view showing an example of a welding apparatus. [Figure 6] Figure 6 is a schematic plan view showing an example of a welding block. [Figure 7] Figure 7 is a cross-sectional view of a welding chamber to illustrate an example of a welding method for laminates. Figure 7(a) shows the state of the welding torch and arc at the start of welding, and Figure 7(b) shows the state of the welding torch and arc during welding. [Figure 8] Figure 8 is a schematic cross-sectional view showing another example of a welding apparatus, where Figure 8(a) shows an example where the laminate consists of 6 block cores, and Figure 8(b) shows an example where the laminate consists of 3 block cores. [Figure 9] Figure 9 is a schematic cross-sectional view showing another example of a welding apparatus, where Figure 9(a) shows an example where the laminate consists of 6 block cores, and Figure 9(b) shows an example where the laminate consists of 3 block cores. [Figure 10] Figure 10 is a schematic cross-sectional view showing another example of a welding apparatus. [Figure 11] Figure 11 is a schematic cross-sectional view showing another example of a welding apparatus. [Modes for carrying out the invention]

[0010] In the following descriptions, the same reference numeral will be used for identical elements or elements with the same function, and redundant explanations will be omitted. Furthermore, in this specification, when referring to the top, bottom, right, and left of a figure, the direction of the reference numeral in the figure will be used as the reference.

[0011] [Structure of the stator laminated core] First, the structure of the stator laminated core 1 will be explained with reference to Figures 1 and 2. The stator laminated core 1 is part of the stator. The stator is constructed by attaching windings (not shown) to the stator laminated core 1. An electric motor is constructed by combining the stator and the rotor.

[0012] The stator laminated core 1 has a cylindrical shape overall. A through hole 1a (central hole) is provided in the central part of the stator laminated core 1, extending along the central axis Ax and penetrating the stator laminated core 1. That is, the through hole 1a extends in the height direction of the stator laminated core 1. A rotor can be placed inside the through hole 1a. The stator laminated core 1, together with the rotor core, constitutes an electric motor. The stator laminated core 1 comprises a laminate 10 and a weld bead 20.

[0013] The laminate 10 consists of multiple block cores B (iron core members) stacked in this order. In the examples shown in Figures 1 and 2, the laminate 10 is constructed by stacking six block cores B1 to B6 in this order from top to bottom. That is, the stacking direction of the laminate 10 is both the height direction of the laminate 10 and the direction of extension of the central axis Ax. Hereafter, the stacking direction of the laminate 10 will simply be referred to as the "stacking direction".

[0014] Block core B is a laminate formed by stacking multiple punched members W, as illustrated in Figure 2. The punched members W are plate-like bodies formed by punching out a predetermined shape from a metal sheet MS (e.g., electrical steel sheet), which will be described later, and have a shape corresponding to the laminate 10. Block core B may also be constructed by so-called roll stacking.

[0015] "Rotation lamination" means that when obtaining the block core B by laminating a plurality of punched members W, the angles between the punched members W are relatively shifted, including laminating while rotating the punched members W. Rotation lamination is mainly carried out for the purpose of offsetting the plate thickness deviation of the punched members W. When obtaining the block core B, the punched members W may be rotationally laminated one by one, or the punched members W may be rotationally laminated in a predetermined number. When laminating a plurality of block cores B to obtain the laminate 10, the block cores B may be rotationally laminated one by one, or the block cores B may be rotationally laminated in a predetermined number.

[0016] Returning to FIG. 1, the laminate 10 includes a yoke portion 11, a plurality of teeth portions 12, a plurality of lug portions 13 (welding portions), and a plurality of caulked portions 14. The yoke portion 11 has an annular shape and extends so as to surround the central axis Ax. As illustrated in FIG. 1 and the like, the yoke portion 11 may have an annular shape. The plurality of teeth portions 12 extend along the radial direction of the yoke portion 11 from the inner edge of the yoke portion 11 toward the central axis Ax side. That is, the plurality of teeth portions 12 protrude from the inner edge of the yoke portion 11 toward the central axis Ax. The plurality of teeth portions 12 may be arranged at substantially equal intervals in the circumferential direction of the yoke portion 11. A slot 15 (through hole), which is a space for arranging a winding, is defined between adjacent teeth portions 12.

[0017] Each lug portion 13 extends along the radial direction of the yoke portion 11 from the outer edge of the yoke portion 11 so as to be away from the central axis Ax. That is, each lug portion 13 protrudes from the outer edge of the yoke portion 11 toward the radially outer side of the yoke portion 11. In the laminate 10 illustrated in FIG. 1, three lug portions 13 are integrally formed on the yoke portion 11. Each lug portion 13 may be arranged at substantially equal intervals in the circumferential direction of the yoke portion 11. Each lug portion 13 extends linearly from one end surface (for example, the upper end surface) to the other end surface (for example, the lower end surface) of the laminate 10 in the lamination direction.

[0018] The lug portion 13 includes a main projection 13a and a secondary projection 13b (welded portion). The main projection 13a is provided on the outer edge of the yoke portion 11 and may have a substantially triangular shape when viewed from above. The main projection 13a is provided with a through hole 16 that penetrates the main projection 13a (lug portion 13) in the stacking direction. The through hole 16 functions, for example, as a bolt insertion hole for fixing the stator stacked core 1 to the motor housing (not shown).

[0019] The crimping portion 14 may be provided, for example, on the yoke portion 11. Although not shown in the figures, the crimping portion 14 may be provided, for example, on each tooth portion 12. Adjacent punched members W in the lamination direction may be fastened together by the crimping portion 14. Multiple punched members W may be fastened together by various known methods instead of the crimping portion 14. Multiple punched members W may be joined together by, for example, an adhesive or resin material. Alternatively, temporary crimping may be provided on the punched members W, and after fastening the multiple punched members W via the temporary crimping to obtain a temporary laminate, the temporary crimping may be removed from the temporary laminate to obtain the block core B. Note that "temporary crimping" refers to crimping used to temporarily integrate multiple punched members W and removed in the process of manufacturing the product (stator laminated core 1).

[0020] The weld bead 20 is formed on the outer surface of the secondary projection 13b. The weld bead 20 extends linearly along the longitudinal direction of the secondary projection 13b, from one end face (e.g., the upper end face) to the other end face (e.g., the lower end face) of the laminate 10. The weld bead 20 joins a plurality of punched members W and a plurality of block cores B that are aligned in the lamination direction.

[0021] [Manufacturing equipment for stator laminated iron cores] Next, with reference to Figure 3, the stator laminated core manufacturing apparatus 100 (laminated core manufacturing apparatus) will be described. The manufacturing apparatus 100 is configured to manufacture the stator laminated core 1 from a strip-shaped metal plate MS. The manufacturing apparatus 100 includes an uncoiler 110, a feeding device 120, a press working device 130, a welding device 200, and a controller Ctr.

[0022] The uncoiler 110 is configured to rotatably hold the coil material 111. The coil material 111 is a metal sheet MS wound in a coil (spiral) shape. The feeding device 120 includes a pair of rollers 121 and 122 that sandwich the metal sheet MS from above and below. The pair of rollers 121 and 122 are configured to rotate and stop based on instruction signals from the controller Ctr, intermittently and sequentially feeding the metal sheet MS toward the press working device 130.

[0023] The press working apparatus 130 is configured to operate based on instruction signals from the controller Ctr. The press working apparatus 130 may be configured to sequentially punch or cut and bend a metal sheet MS fed by the feeder 120 using multiple punches to form multiple punched members W. The press working apparatus 130 may be configured to sequentially stack the multiple punched members W obtained by punching to form a block core B. The block core B formed by the press working apparatus 130 may be transported to the welding apparatus 200 by, for example, a conveyor Cv, or by human intervention.

[0024] The welding apparatus 200 operates based on instruction signals from the controller Ctr and is configured to weld the lug portion 13 (sub-projection portion 13b) of the laminate 10, which is made up of multiple stacked block cores B. Details of the welding apparatus 200 will be described later.

[0025] The controller Ctr is configured to generate signals to operate the dispensing device 120, the press working device 130, the welding device 200, and the conveyor Cv, based on, for example, a program recorded on a recording medium (not shown) or operation input from an operator. The controller Ctr is configured to transmit these signals to the dispensing device 120, the press working device 130, the welding device 200, and the conveyor Cv, respectively.

[0026] [Details of the welding equipment] Next, the details of the welding apparatus 200 will be described with reference to Figures 4 to 6. The welding apparatus 200 comprises a lower plate 210, a plurality of guide shafts 220 (positioning members), a plurality of positioning pins 230 (positioning members), a plurality of guide rails 240, an expander 250, an upper plate 260, a drive unit 270 (the above is also called the "welding jig"), and a welding machine 280.

[0027] The lower plate 210 is a plate-like member having a substantially circular shape, as illustrated in Figure 4. The lower plate 210 is configured to support the laminate 10 (multiple block cores B) placed on its upper surface. The upper surface of the lower plate 210 is provided with a plurality of recesses 210a, as illustrated in Figures 4 and 5. The number and position of the plurality of recesses 210a may correspond to the number and position of the lugs 13 of the laminate 10. Therefore, the plurality of recesses 210a may be arranged at substantially equal intervals along the circumferential direction of the laminate 10 to form a circular shape.

[0028] A welding block 211 is positioned within the recess 210a. As illustrated in Figure 6, the welding block 211 is provided with a pair of through holes 211a. In a plan view, the through holes 211a are elongated holes extending along the radial direction of the lower plate 210. The welding block 211 is attached to the recess 210a of the lower plate 210 by bolts BT inserted through the through holes 211a. The position of the welding block 211 relative to the lower plate 210 is adjusted according to the position of the bolts BT inserted through the through holes 211a.

[0029] The welding block 211 includes a recessed portion 211b that corresponds to the secondary protrusion 13b in a plan view. The recessed portion 211b includes a pair of valleys 211c that correspond to the shape of the secondary protrusion 13b of the lug portion 13, and a peak portion 211d that is located in the center of the pair of valleys 211c and corresponds to the shape of the secondary protrusion 13b of the lug portion 13. The peak portion 211d includes an opposing surface S1 that faces the laminate 10 when the laminate 10 is sandwiched between the lower plate 210 and the upper plate 260 (hereinafter simply referred to as the "sandwiched state"). As illustrated in Figure 5, the opposing surface S1 is inclined to expand radially outward from the laminate 10 as it moves away from the laminate 10 in the lamination direction. In other words, the opposing surface S1 is formed by chamfering the portion of the peak portion 211d that is on the upper side of the lower plate 210.

[0030] Multiple guide shafts 220, multiple positioning pins 230, and multiple guide rails 240 are attached to the lower plate 210 so as to protrude upward from the upper surface of the lower plate 210. Multiple guide shafts 220, multiple positioning pins 230, and multiple guide rails 240 may be fixed to the lower plate 210 or may be detachably attached to the lower plate 210.

[0031] The guide shaft 220 is configured to support the laminate 10 against the lower plate 210 by being inserted through the through hole 16 of the lug portion 13. Therefore, the guide shaft 220 does not necessarily have to be in contact with the through hole 16. The number and position of the multiple guide shafts 220 may correspond to the number and position of the lug portions 13 of the laminate 10. The multiple guide shafts 220 may be arranged at approximately equal intervals along the circumferential direction of the laminate 10 to form a circular shape. The outer shape of the multiple guide shafts 220 may be cylindrical, or it may be a shape corresponding to the shape of the through hole 16.

[0032] A groove 221 is formed at the upper end of the guide shaft 220, as illustrated in Figure 4. The groove 221 may extend around the entire circumference of the guide shaft 220, or it may extend only partially in the circumferential direction of the guide shaft 220. The position of the groove 221 on the guide shaft 220 corresponds to the boundary between the upper plate 260 and the laminate 10 in the clamping state. The position of the groove 221 may be set such that the center of the groove 221 in the lamination direction substantially coincides with the said boundary.

[0033] Although not shown in the diagram, the side walls of the groove 221 may be inclined such that the opening width of the groove 221 decreases towards the bottom wall of the groove 221. In other words, the opening edge of the groove 221 may be chamfered. The opening width of the groove 221 on the surface of the guide shaft 220 (length of the groove 221 in the stacking direction) is not particularly limited, but may be, for example, about 3 mm to 8 mm.

[0034] The positioning pins 230 are inserted into the slots 15 and contact the inner circumferential surface of the slots 15, thereby positioning the laminate 10 relative to the lower plate 210. The number of positioning pins 230 may be less than or equal to the number of slots 15. The positions of the positioning pins 230 may correspond to the positions of the slots 15. The positioning pins 230 may be arranged at approximately equal intervals along the circumferential direction of the laminate 10 to form a circular shape. The outer shape of the positioning pins 230 may be cylindrical, or it may be a shape corresponding to the shape of the slots 15.

[0035] A groove 231 is formed at the upper end of the positioning pin 230, as illustrated in Figure 4. The groove 231 may extend around the entire circumference of the positioning pin 230, or it may extend only partially in the circumferential direction of the positioning pin 230. The position of the groove 231 on the positioning pin 230 corresponds to the boundary between the upper plate 260 and the laminate 10 in the clamping state. The position of the groove 231 may be set such that the center of the groove 231 in the lamination direction substantially coincides with the said boundary.

[0036] As illustrated in Figure 5, the side walls of the groove 231 may be inclined such that the opening width of the groove 231 decreases towards the bottom wall of the groove 231. In other words, the opening edge of the groove 231 may be chamfered. The opening width of the groove 231 on the surface of the positioning pin 230 (length of the groove 231 in the stacking direction) is not particularly limited, but may be, for example, about 3 mm to 8 mm.

[0037] The guide rail 240 is configured to slide the diameter-expanding member 251, described later, horizontally and along the direction of extension of the guide rail 240. The number and position of the multiple guide rails 240 may correspond to the number and position of the diameter-expanding member 251. The multiple guide rails 240 extend radially outward from the center of the lower plate 210. In a plan view, the multiple guide rails 240 are arranged at approximately equal intervals to form a circular shape.

[0038] The diameter expanding tool 250 includes a plurality of diameter expanding members 251 (positioning members) and a thruster member 252, as illustrated in Figures 4 and 5. The plurality of diameter expanding members 251 are arranged at approximately equal intervals so as to form a circular shape in plan view. The diameter expanding members 251 have a fan shape when viewed from above. The diameter expanding members 251 can be obtained, for example, by dividing an annular columnar body into multiple parts. Both the upper and lower surfaces of the diameter expanding member 251 are composed of an arc-shaped outer circumferential edge, an arc-shaped inner circumferential edge that is shorter in length than the outer circumferential edge, a straight side edge connecting one end of the outer circumferential edge to one end of the inner circumferential edge, and a straight side edge connecting the other end of the outer circumferential edge to the other end of the inner circumferential edge. The inner circumferential surface S2 of the diameter expanding member 251 has an inclined surface that approaches inward as it goes downward.

[0039] The diameter-expanding member 251 is provided with a through hole 251a. The through hole 251a is an elongated hole extending between the inner circumferential surface S2 and the outer circumferential surface of the diameter-expanding member 251. A corresponding guide rail 240 can be inserted into the through hole 251a. The length of the through hole 251a is longer than the length of the guide rail 240. Therefore, the diameter-expanding member 251 can move along the extending direction of the guide rail 240. Note that it does not have to be a through hole 251a as long as it can accommodate the guide rail 240; for example, instead of a through hole 251a, a recess with an elongated opening may be provided in the diameter-expanding member 251.

[0040] A groove 251b is formed at the upper end of the diameter-expanding member 251, as illustrated in Figure 4. The groove 251b may extend along the entire circumferential direction on the outer surface of the diameter-expanding member 251, or it may extend partially along the circumferential direction on the outer surface of the diameter-expanding member 251. The position of the groove 251b on the diameter-expanding member 251 corresponds to the boundary between the upper plate 260 and the laminate 10 in the clamping state. The position of the groove 251b may be set such that the center of the groove 251b in the lamination direction substantially coincides with the said boundary.

[0041] Although not shown in the diagram, the side walls of the groove 251b may be inclined such that the opening width of the groove 251b decreases towards the bottom wall of the groove 251b. In other words, the edge on the opening side of the groove 251b may be chamfered. The opening width of the groove 251b on the outer surface of the diameter-enlarging member 251 (length of the groove 251b in the stacking direction) is not particularly limited, but may be, for example, about 3 mm to 8 mm.

[0042] The diameter-expanding member 251 includes a corner portion 251c located on the outer surface side of the diameter-expanding member 251 and extending along the lamination direction. The corner portion 251c may be chamfered overall (e.g., C-chamfer, R-chamfer, etc.), as illustrated in Figure 4. Alternatively, the corner portion 251c may be chamfered in the portion corresponding to the boundary between the upper plate 260 and the laminate 10 when clamped.

[0043] As illustrated in Figure 5, the plunger member 252 is positioned within the inner circumferential surface S2 of the diameter-expanding member 251. The plunger member 252 has a frustoconical shape that narrows in diameter towards its tip (lower end). Therefore, the outer circumferential surface of the plunger member 252 is conical and has a shape corresponding to the inner circumferential surface S2 of the diameter-expanding member 251.

[0044] The upper plate 260 is a plate-like member with a substantially circular shape, as illustrated in Figure 4. The upper plate 260 is placed on top of the laminate 10 which is placed on the lower plate 210. The upper plate 260 is provided with a through hole 261, a plurality of through holes 262, and a plurality of through holes 263, as illustrated in Figures 4 and 5.

[0045] The through-hole 261 is through which the diameter expander 250 can be inserted. The through-hole 261 is circular in shape and is located in the center of the upper plate 260. The through-hole 261 may be approximately the same size as or slightly larger than the inner diameter of the laminate 10.

[0046] The through-holes 262 through which the guide shafts 220 can be inserted. The number and positions of the multiple through-holes 262 may correspond to the number and positions of the guide shafts 220. Therefore, the multiple through-holes 262 may be arranged at approximately equal intervals along the circumferential direction of the laminate 10 to form a circular shape. The through-holes 262 may be about the same size as or slightly larger than the outer diameter of the guide shafts 220.

[0047] The through-holes 263 through which the positioning pins 230 can be inserted. The number and positions of the multiple through-holes 263 may correspond to the number and positions of the positioning pins 230. Therefore, the multiple through-holes 263 may be arranged at approximately equal intervals along the circumferential direction of the laminate 10 to form a circular shape. The through-holes 263 may be about the same size as or slightly larger than the outer diameter of the positioning pins 230.

[0048] The lower surface of the upper plate 260 is provided with a plurality of recesses 260a. The number and position of the plurality of recesses 260a may correspond to the number and position of the lugs 13 of the laminate 10. Therefore, the plurality of recesses 260a may be arranged at approximately equal intervals along the circumferential direction of the laminate 10 to form a circular shape.

[0049] A welding block 264 is positioned within the recess 260a. The welding block 264 has a configuration substantially the same as that of the welding block 211. Therefore, details will be omitted, but as illustrated in Figure 6, the welding block 264 includes a through hole 264a and a recessed portion 264b. The recessed portion 264b includes a valley portion 264c and a peak portion 264d. The peak portion 264d includes an opposing surface S3 that faces the laminate 10 in the clamped state. As illustrated in Figure 5, the opposing surface S3 is inclined to expand radially outward from the laminate 10 as it moves away from the laminate 10 in the stacking direction. In other words, the opposing surface S3 is formed by chamfering the portion of the peak portion 264d that is on the lower side of the upper plate 260.

[0050] The drive unit 270 is configured to move the upper plate 260 up and down, bringing the upper plate 260 closer to or further away from the lower plate 210. The drive unit 270 may be a linear motion mechanism such as an air cylinder, hydraulic cylinder, or electric cylinder.

[0051] The welding machine 280 is configured to weld the lug portion 13 (sub-projection portion 13b). The welding machine 280 may be a welding machine that uses the arc welding method. As for the arc welding method, for example, it may be a consumable electrode type in which the electrode is melted and used as filler material, or it may be a non-consumable electrode type in which a non-consumable electrode is used and filler material is added separately. An example of a non-consumable electrode type is TIG welding.

[0052] The welding machine 280 may include an anode member 281 electrically connected to the anode of the power supply and a welding torch 282 electrically connected to the cathode of the power supply, as illustrated in Figure 5. The anode member 281 may be connected to the lower plate 210, or to the upper plate 260, or to the lower plate 210 and the upper plate 260, respectively, during welding.

[0053] The welding torch 282 is connected to a drive source (not shown) and is configured to move along the stacking direction from one of the lower plate 210 and the upper plate 260 to the other. When a voltage is applied to the anode member 281 and the welding torch 282, a potential difference is generated between the welding jig, including the stack 10, lower plate 210, guide shaft 220, positioning pin 230, diameter expanding member 251, and upper plate 260, and the tip (electrode rod) of the welding torch 282, causing an arc to be generated from the tip of the welding torch 282 toward the welding jig.

[0054] [Manufacturing method for stator laminated iron core] Next, with reference to Figures 3 to 7, the manufacturing method of the stator laminated core 1 will be described. First, as shown in Figure 3, based on the instructions of the controller Ctr, the press working apparatus 130 sequentially punches out metal plates MS and stacks multiple punched members W to form a block core B. The block core B discharged from the press working apparatus 130 is transported to the welding apparatus 200 by a conveyor Cv. At this time, a member with a guide shaft 220 attached to the lower plate 210 may be configured as a transport member CM (see Figure 4), and the transport member CM may be transported to the welding apparatus 200 by the conveyor Cv with multiple block cores B placed on it. Alternatively, multiple block cores B may be placed on the transport member CM while being rolled, and a laminate 10 may be formed on the transport member CM.

[0055] Next, with the laminate 10 placed on the transport member CM, multiple positioning pins 230 are inserted into the corresponding slots 15 (see Figure 5). Also, with the laminate 10 placed on the transport member CM, the diameter expander 250 is placed in the central hole of the laminate 10 (corresponding to the through hole 1a of the stator laminate core 1) (see the same). These steps may be performed in any order, or approximately simultaneously.

[0056] Next, the plunger member 252 of the diameter expander 250 is pushed downward. As a result, the plunger member 252 is pressed against each diameter expander 251 while the circumferential surface (conical surface) of the plunger member 252 remains in contact with the inner circumferential surface S2 of each diameter expander 251. Therefore, the circumferential surface (conical surface) of the plunger member 252 slides along the inner circumferential surface S2, applying an outward force to the inner circumferential surface S2. Consequently, each diameter expander 251 moves radially outward of the laminate 10 while being guided by the guide rail 240. As a result, the circumferential surface of each diameter expander 251 comes into contact with the inner circumferential surface of the central hole of the laminate 10 (the tip surface of each tooth portion 12), applying a radially outward force to them.

[0057] Next, the upper plate 260 is placed on the laminate 10. Specifically, the upper plate 260 is lowered toward the laminate 10 by the drive unit 270 so that the diameter expander 250 is inserted through the through hole 261 of the upper plate 260, one guide shaft 220 is inserted through each through hole 262, and one positioning pin 230 is inserted through each through hole 263. As a result, the laminate 10 is sandwiched between the lower plate 210 and the upper plate 260, and a load of a predetermined size is applied to the laminate 10.

[0058] In this clamping state, the groove 221 in the guide shaft 220 is located at the boundary between the upper plate 260 and the laminate 10. In this clamping state, as illustrated in Figure 7, the groove 231 in the positioning pin 230 is located at the boundary between the upper plate 260 and the laminate 10. In this clamping state, as illustrated in Figure 7, the groove 251b in the diameter-expanding member 251 is located at the boundary between the upper plate 260 and the laminate 10.

[0059] Next, the anode member 281 is connected to at least one of the lower plate 210 and the upper plate 260 (see Figure 7). Then, the welding torch 282 is positioned so that its tip faces, for example, the welding block 264 of the upper plate 260. In this case, the upper plate 260 becomes the welding start plate. In this state, by applying a voltage to the anode member 281 and the welding torch 282, an arc is generated from the tip of the welding torch 282 toward the welding block 264 (see Figure 7(a)).

[0060] Next, while the arc is still generated, the welding torch 282 is moved toward the welding block 211 of the lower plate 210 along the stacking direction. As a result, the secondary protrusion 13b is welded along the stacking direction, and a welding bead 20 is formed on the secondary protrusion 13b. With this, the stator laminated core 1, which is a laminate of multiple block cores B, is completed.

[0061] [Effect] In the above example, grooves 221, 231, and 251b are formed in the guide shaft 220, positioning pin 230, and diameter-expanding member 251 (hereinafter collectively referred to as "positioning member"), and the grooves 221, 231, and 251b are located at the boundary between the upper plate 260 (welding start plate) and the laminate 10 in the clamping state. As a result, the distance between the positioning member and the laminate 10 (block core B) is increased, making it difficult for arc discharge to occur between the positioning member and the laminate 10 (block core B). Therefore, it is possible to suppress unintended melting of areas of the laminate 10 (block core B) or the positioning member.

[0062] As shown in the above example, chamfers can be formed on the opening edges of grooves 221, 231, and 251b. In this case, the opening edges of grooves 221, 231, and 251b are separated from the boundary between the upper plate 260 (welding start plate) and the laminate 10 (block core B) in the clamped state. Therefore, arc discharge between the positioning member and the laminate 10 (block core B) becomes less likely.

[0063] As shown in the above example, a chamfer can be formed on the corner 251c of the diameter-expanding member 251. In this case, the chamfering process separates the corner 251c of the diameter-expanding member 251 from the laminate 10 (block core B). Therefore, arc discharge between the positioning member and the laminate 10 (block core B) becomes less likely.

[0064] In the above example, the opposing surfaces S1 and S3 are inclined surfaces. Therefore, at the start of arc discharge, the opposing surface S3 of the upper plate 260 (welding start plate) and the welding torch 282 are in close proximity, resulting in a stable start to arc discharge. On the other hand, when the welding torch 282 moves in the stacking direction and the arc moves from the welding block 264 to the stacked body 10, the step difference between the opposing surface S3 and the stacked body 10 becomes small or almost nonexistent, so the stacked body 10 is welded without the arc jumping over the portion of the secondary protrusion 13b near the upper end surface of the stacked body 10. The same is true near the end of welding the stacked body 10, when the opposing surface S1 of the lower plate 210 (welding end plate) and the welding torch 282 are in close proximity, resulting in a stable start to arc discharge. On the other hand, when the welding torch 282 moves in the stacking direction and the arc moves from the stacked body 10 to the welding block 211, the step difference between the opposing surface S1 and the stacked body 10 becomes small or almost nonexistent, so the stacked body 10 is welded without the arc jumping over the portion of the secondary protrusion 13b near the end face of the stacked body 10. Therefore, it is possible to improve the welding quality of the secondary protrusion 13b.

[0065] [Differentiation] The disclosures herein should be considered in all respects to be illustrative and not restrictive. Various omissions, substitutions, and modifications may be made to the above examples without departing from the claims and the gist thereof.

[0066] (1) The above techniques may be applied when manufacturing other laminated cores other than the stator laminated core 1. Other laminated cores may be, for example, rotor laminated cores.

[0067] (2) In the above example, the laminate 10 was composed of multiple block cores B stacked together, but it may also be composed of a single laminate made of multiple punched members W stacked together.

[0068] (3) Parts of the laminate 10 other than the lug portion 13 may be welded. For example, the outer surface of the laminate 10 may be welded, or the inner surface of the laminate 10 (the inner surface of the through hole 1a) may be welded. In these cases, grooves may be provided at the welded locations on the outer or inner surface of the laminate 10. The grooves may, for example, extend along the lamination direction of the laminate 10.

[0069] (4) In the above example, the weld bead 20 extended linearly along the longitudinal direction of the secondary protrusion 13b from one end face to the other of the laminate 10, but the form of the weld bead 20 is not limited to this. For example, the weld bead 20 may partially extend in the lamination direction of the laminate 10 near each boundary so as to join the boundary portions of the block cores B. For example, the weld bead 20 may be spot welded at the boundary portions of the block cores B so as to join the boundary portions of the block cores B. For example, the weld bead 20 may extend continuously from the uppermost boundary to the lowermost boundary of the boundary portions of the block cores B so as to join all the boundary portions of the block cores B, and may not reach each end face of the laminate 10. Alternatively, the weld bead 20 may be a combination of the above examples.

[0070] (5) The welding torch 282 may be moved along the lamination direction from the welding block 211 of the lower plate 210 toward the welding block 264 of the upper plate 260. In this case, the grooves 221, 231, and 251b may be located at the boundary between the lower plate 210 (welding start plate) and the laminate 10 (block core B) in the clamped state.

[0071] (6) The shape of the through holes 211a and 264a is not particularly limited, as long as they are larger than the diameter of the bolt BT and smaller than the head of the bolt BT. In this case, when the welding blocks 211 and 264 are not fixed to the lower plate 210 or upper plate 260 by the bolt BT, the welding blocks 211 and 264 become movable relative to the lower plate 210 or upper plate 260. Therefore, the position of the welding blocks 211 and 264 relative to the lower plate 210 or upper plate 260 can be adjusted as appropriate. The shape of the through holes 211a and 264a may be circular, elliptical, or rectangular, for example, instead of being elongated.

[0072] (7) In the above examples, grooves 221, 231, and 251b were formed in the guide shaft 220, the positioning pin 230, and the diameter-expanding member 251, respectively, but a recess may be formed in at least one of these. Alternatively, a groove may be formed at the boundary between the welding start plate and the laminate 10 (block core B) in the clamping state for other positioning members that position the laminate 10 when the laminate 10 is welded.

[0073] (8) In the above examples, the diameter expander 250 was placed in the central hole of the laminate 10, but the diameter expander 250 is not required to be used. For example, a column member having an outer shape along the central hole may be placed in the central hole of the laminate 10. The column member may be provided on the lower plate 210. Alternatively, no member may be placed in the central hole of the laminate 10.

[0074] (9) As illustrated in Figures 8 and 9, a single positioning member may have multiple grooves. For example, when a single laminate 10 is constructed from six block cores B, as illustrated in Figures 8(a) and 9(a), the groove provided at the upper end of the positioning member will be located at the boundary between the upper plate 260 (welding start plate) and the laminate 10 in the clamping state. On the other hand, for example, when a single laminate 10 is constructed from three block cores B, as illustrated in Figures 8(b) and 9(b), the groove provided in the center of the positioning member will be located at the boundary between the upper plate 260 (welding start plate) and the laminate 10 in the clamping state. In this case, multiple types of laminates 10 can be welded using a single positioning member. Therefore, it is possible to reduce the effort and cost of preparing multiple types of positioning members corresponding to different types of laminates 10, or of changing the positioning member each time a different type of laminate 10 is welded.

[0075] As illustrated in Figure 8, if the heights of the six block cores B constituting one laminate 10 (see Figure 8(a)) and the heights of the three block cores B constituting another laminate 10 (see Figure 8(b)) are substantially the same, the multiple grooves formed on one positioning member may be arranged at substantially equal intervals with respect to the surface of the lower plate 210. On the other hand, as illustrated in Figure 9, if the heights of the six block cores B constituting one laminate 10 (see Figure 9(a)) and the heights of the three block cores B constituting another laminate 10 (see Figure 9(b)) are different, the multiple grooves formed on one positioning member do not need to be arranged at substantially equal intervals with respect to the surface of the lower plate 210.

[0076] (10) As illustrated in Figure 10, the grooves formed in the positioning member may be located at any two adjacent boundaries of the multiple block cores B. In this case, unintended arc discharges are less likely to occur in the portion of the positioning member corresponding to the two adjacent boundaries of the multiple block cores B.

[0077] (11) The opposing surfaces S1 and S3 may have various shapes. For example, as illustrated in Figure 11(a), the portion of the opposing surfaces S1 and S3 closer to the laminate 10 in the stacking direction may extend linearly along the vertical direction, and the portion of the opposing surfaces S1 and S3 further from the laminate 10 in the stacking direction may be an inclined surface. As illustrated in Figure 11(b), the peaks 211d and 261d of the welding blocks 211 and 264 may form opposing surfaces S1 and S3 that are inclined overall. As illustrated in Figure 11(c), the portion of the opposing surfaces S1 and S3 closer to the laminate 10 in the stacking direction may extend linearly along the vertical direction, and the portion of the opposing surfaces S1 and S3 further from the laminate 10 in the stacking direction may have a stepped shape that protrudes radially outward from the laminate 10. Of these opposing surfaces S1 and S3, the edge on the laminate 10 side may be located on the central axis Ax side of the outer circumferential surface of the laminate 10 in the radial direction of the laminate 10, or it may be located outward from the outer circumferential surface of the laminate 10.

[0078] (12) As illustrated in Figure 11(d), opposing surfaces S1 and S3 do not necessarily have to be formed on the peaks 211d and 261d. Alternatively, opposing surfaces S1 and S3 may be formed on at least one of the peaks 211d and 261d.

[0079] [Other examples] Example 1. An example of a method for manufacturing a laminated core is a method for manufacturing a laminated core comprising a laminate formed by stacking a plurality of punched members, a plurality of through holes extending along the stacking direction of the laminate, and a welded portion formed by welding at least a part of the laminate in the stacking direction, comprising: placing a positioning member in the through holes of the laminate, placing the laminate on a lower plate, placing an upper plate above the laminate, placing a positioning member, placing the laminate on a lower plate, and placing an upper plate above the laminate, followed by welding the welded portion with a welding torch while the laminate is sandwiched between the upper plate and the lower plate. A groove is formed in the positioning member. The groove is located in the part of the positioning member corresponding to the boundary between at least one of the upper plate and the lower plate and the laminate.

[0080] Incidentally, when welding a welded joint, unintended arc discharges can occur in the gap between the laminate and the positioning member. In particular, just before an arc discharge occurs, the current flow is unstable, which can cause unintended arc discharges to occur in the portion of the positioning member corresponding to the boundary between at least one of the upper and lower plates and the laminate.

[0081] However, according to Example 1, a groove is formed in that part of the positioning member. Therefore, the distance between the positioning member and the laminate is increased, making it less likely for arc discharge to occur between the positioning member and the laminate. Consequently, it is possible to suppress the melting of unintended areas of the laminate or positioning member.

[0082] Example 2. In the method of Example 1, another groove is formed in the positioning member, and this other groove is located in the part of the positioning member corresponding to the boundary between at least one of the upper plate and the lower plate and another laminate, and the height of the other laminate may differ from the height of the laminate. In this case, when welding one laminate or when welding another laminate, the presence of the groove and the other groove makes it difficult for arc discharge to occur between the positioning member and the laminate. Therefore, multiple types of laminates can be welded using a single positioning member. Thus, it is possible to reduce the effort and cost of preparing multiple types of positioning members corresponding to different types of laminates, or changing the positioning member each time a different type of laminate is welded.

[0083] Example 3. In the method of Example 1, the laminate is composed of multiple block cores stacked together, each of the multiple block cores is composed of multiple punched members stacked together, and the positioning member has another groove formed therein, which may be located in the part of the positioning member corresponding to any two adjacent boundaries of the multiple block cores. In this case, unintended arc discharge is less likely to occur in the part of the positioning member corresponding to the two adjacent boundaries of the multiple block cores.

[0084] Example 4. In any of the methods in Examples 1 to 3, the side walls of the groove may be inclined such that the opening width of the groove decreases towards the bottom wall of the groove. In this case, the edge on the opening side of the groove is separated from the boundary between the welding start plate and the laminate. Therefore, arc discharge between the positioning member and the laminate becomes less likely.

[0085] Example 5. In any of the methods of Examples 1 to 4, the through hole includes a central hole provided in the center of the laminate, the positioning member includes a plurality of diameter-expanding members configured to be movable in the radial direction of the laminate and arranged in a circular pattern along the circumferential direction of the laminate within the central hole, and arranging the positioning member includes arranging the plurality of diameter-expanding members within the central hole and moving them radially outward of the laminate to bring the plurality of diameter-expanding members into contact with the inner circumferential surface of the central hole, each of the plurality of diameter-expanding members includes a corner located on its outer surface side and extending along the lamination direction of the laminate, and a chamfer may be formed on the portion of the corner corresponding to the boundary between at least one of the upper plate and the lower plate and the laminate. In this case, the chamfering process separates the corner of the diameter-expanding member from the boundary between at least one of the upper plate and the lower plate and the laminate. Therefore, arc discharge between the positioning member and the laminate becomes less likely.

[0086] Example 6. In any of the methods in Examples 1 to 5, the weld extends along the stacking direction of the laminate, and welding the weld may include welding the weld along the stacking direction of the laminate with a welding torch from a welding start plate, which is one of the upper plate and the lower plate, toward the other of the upper plate and the lower plate.

[0087] Example 7. In the method of Example 6, the welding start plate includes opposing surfaces that face the weld area while the upper plate and lower plate are sandwiching the laminate, and the opposing surfaces may be inclined so as to widen radially outward from the laminate as they move away from the laminate in the lamination direction, or they may have a stepped shape in which the part furthest from the laminate protrudes radially outward from the laminate compared to the part closer to the laminate in the lamination direction.

[0088] Incidentally, in order to weld a weld along the entire length of a laminate along its lamination direction, an arc discharge is first generated between the welding start plate and the welding torch, and the welding torch is moved in the lamination direction while maintaining the arc. Therefore, if the welding start plate and the welding torch are close together, the start of the arc discharge is stable. However, if the laminate and the welding torch are close together, the amount of heat input to the laminate may increase, causing the laminate to melt excessively, or the electrode rod of the welding torch will wear out quickly, requiring frequent replacement of the electrode rod. On the other hand, if the welding start plate is made to protrude radially outward from the laminate, creating a step between the welding start plate and the laminate, the welding start plate and the welding torch will be close together, and the start of the arc discharge will be stable. However, when the welding torch moves in the lamination direction and the arc crosses the step, there is a possibility that the arc may skip over a portion of the weld near the end face of the laminate, and that portion may not be welded.

[0089] In contrast, according to Example 7, the opposing surface of the welding start plate is inclined or stepped. Therefore, at the start of arc discharge, the welding start plate (opposing surface) and the welding torch are in close proximity, resulting in a stable start to arc discharge. On the other hand, as the welding torch moves in the stacking direction and the arc moves to the stacked material, the step difference between the opposing surface and the stacked material becomes small or almost nonexistent, so the portion of the weld near the edge of the stacked material is welded without the arc jumping over it. This makes it possible to improve the welding quality of the welded area.

[0090] Example 8. An example of a laminated core manufacturing apparatus comprises a lower plate configured to support a laminate on which a plurality of punched members are stacked, a positioning member configured to position the laminate relative to the lower plate by being placed in a through hole extending along the stacking direction of the laminate, an upper plate configured to be placed above the laminate, and a welding torch configured to weld a welded portion provided on the laminate while the laminate is sandwiched between the upper and lower plates. A groove is formed in the positioning member. The groove is located in the part of the positioning member corresponding to the boundary between at least one of the upper plate and the lower plate and the laminate. In this case, the same effects as in Example 1 can be obtained. [Explanation of Symbols]

[0091] 1... Stator laminated core, 1a... Through hole (center hole), 10... Laminate, 13... Lug part (welded part), 13b... Sub-projection part (welded part), 15... Slot (through hole), 16... Through hole, 100... Stator laminated core manufacturing equipment (laminated core manufacturing equipment), 200... Welding equipment, 210... Lower plate, 220... Guide shaft (positioning member), 221... Groove, 230... Positioning pin (positioning member), 231... Groove, 250... Diameter expander, 251b... Groove, 251c... Corner, 251... Diameter expander (positioning member), 280... Welding machine, 282... Welding torch, B, B1~B6... Block core, S1, S3... Opposing surface, W... Punched member.

Claims

1. A method for manufacturing a laminated iron core comprising a laminate formed by stacking multiple punched members, a plurality of through holes extending along the stacking direction of the laminate, and a welded portion formed by welding at least a part of the laminate in the stacking direction, Positioning members are placed in the through holes of the laminate, The laminate is placed on the lower plate, The upper plate is placed on top of the aforementioned laminate, The process includes arranging the positioning member, placing the laminate on the lower plate, and placing the upper plate above the laminate, and then welding the weld portion with a welding torch while the laminate is sandwiched between the upper plate and the lower plate and the positioning member is positioned in the through hole of the laminate. The positioning member has a recessed groove formed therein. A method for manufacturing a laminated core, wherein the groove is located in a portion of the positioning member corresponding to the boundary between at least one of the upper plate and the lower plate and the laminate.

2. The positioning member has another groove formed therein, The aforementioned additional groove is located in the positioning member in a portion corresponding to the boundary between at least one of the upper plate and the lower plate and another laminate. The method according to claim 1, wherein the height of the other laminate is different from the height of the laminate.

3. The aforementioned laminate is composed of multiple block cores stacked on top of each other. Each of the aforementioned plurality of block cores is constructed by stacking the aforementioned plurality of punched members. The positioning member has another groove formed therein, The method according to claim 1 or 2, wherein the other groove is located in the positioning member in a portion corresponding to any two adjacent boundaries of the plurality of block cores.

4. The method according to any one of claims 1 to 3, wherein the side walls of the groove are inclined such that the opening width of the groove decreases as it approaches the bottom wall of the groove.

5. The through hole includes a central hole located in the center of the laminate. The positioning member includes a plurality of diameter-expanding members configured to be movable in the radial direction of the laminate and arranged in a circular pattern within the central hole along the circumferential direction of the laminate. The positioning member is positioned by placing the plurality of diameter-expanding members within the central hole and moving them radially outward of the laminate, thereby bringing the plurality of diameter-expanding members into contact with the inner circumferential surface of the central hole. Each of the aforementioned multiple diameter-enlarging members is located on its outer surface and includes a corner portion that extends along the stacking direction of the laminate. The method according to any one of claims 1 to 4, wherein a chamfer is formed on the portion of the corner corresponding to the boundary between at least one of the upper plate and the lower plate and the laminate.

6. The welded portion extends along the stacking direction of the laminate, The method according to any one of claims 1 to 5, wherein welding the weld portion is performed by welding the weld portion with a welding torch from a welding start plate, which is one of the upper plate and the lower plate, toward the other of the upper plate and the lower plate, along the lamination direction of the laminate.

7. The welding start plate includes opposing surfaces that face the welding portion while the upper plate and the lower plate are sandwiching the laminate, The method according to claim 6, wherein the opposing surfaces are inclined to widen radially outward from the laminate as they move away from the laminate in the stacking direction, or have a stepped shape in which the portion further away from the laminate protrudes radially outward from the laminate compared to the portion closer to the laminate in the stacking direction.

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