Method of manufacturing motor core

Abstract

To join blocks together without depending on welding.SOLUTION: In a first step of a block formation step, a first cut core plate 13 is stacked on an iron core piece 12. In a second step, a second cut core plate 14 is stacked on the first core plate 13. In the first step, a dowel 16 of the first cut core plate 13 is aligned with a dowel 16 of the iron core piece 12. In the second step, a dowel 16 of the second cut core plate 14 is aligned with a through hole 19 of the first cut core plate 13. When the iron core piece 12 is stacked on the second cut core plate 14 after the second step, the dowel 16 of the iron core piece 12 is aligned with the dowel 16 of the second cut core plate 14. In a core formation step, a plurality of blocks 11 are rotationally stacked so that the dowel 16 of the first cut core plate 13 and the dowel 16 of the second cut core plate 14 overlap together, and in such the state, the blocks 11 are joined together by swaging the dowels 16.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present disclosure relates to a method for manufacturing a motor core. [Background technology]

[0002] A motor core such as a rotor core and a stator core in a motor is formed by a motor core manufacturing method that includes a block forming step and a core forming step. In the block forming process, as shown in Patent Document 1, for example, core pieces having dowels are punched out of a thin plate-shaped material, and then the core pieces are stacked so that the dowels overlap, thereby forming a block. When the block is formed in this manner, the overlapping dowels of each core piece are crimped together, thereby joining the core pieces to each other.

[0003] Furthermore, in the block forming process, each time the core pieces are stacked multiple times, a cut core plate with a through hole is punched out of the material and stacked on the multiple core pieces. The through holes in the cut core plate are positioned to correspond to the dowels of the core pieces. Therefore, the cut core plate is placed in the bottom layer of the stacked core pieces in the block formed in the block forming process. This cut core plate prevents adjacent blocks from being joined by crimping the dowels.

[0004] The blocks formed in the block forming process are stacked in the direction of the centerline in the number required to form the motor core so that they are suitable for transportation. The stacked blocks are then transported to a pressing device where they are pressed. In this pressing device, the blocks are pressed in the direction of the centerline to compress them. The pressing process is intended to further strengthen the crimped joint between the stacked dowels of each core piece in the block.

[0005] After the pressing process, the core forming process is carried out, in which the pressed blocks are welded together to form the motor core. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2020-58097 Summary of the Invention [Problem to be solved by the invention]

[0007] In the motor core manufacturing method described above, the motor core is formed by welding blocks together in the core formation process, which requires equipment and labor for welding. Furthermore, as the joints between the iron cores become larger when the blocks are welded together, eddy currents generated in the motor increase, reducing the motor's product performance. [Means for solving the problem]

[0008] The means for solving the above problems and their effects will be described below. A motor core manufacturing method that solves the above problem includes a block forming process and a core forming process. In the block forming process, core pieces having dowels are punched out of a thin sheet material and stacked so that the dowels overlap, thereby forming a block. In the core forming process, a plurality of blocks are stacked and joined together to form a motor core. In the block forming process, a first process and a second process are performed each time the core pieces are stacked multiple times. In the first process, a first cut core plate having dowels and through holes is punched out of the material and stacked on the plurality of core pieces. In the second process, a second cut core plate having dowels and through holes is punched out of the material and stacked on the first cut core plate. By performing these first and second processes, the first cut core plate and the second cut core plate are arranged at both ends of the block in the stacking direction of the core pieces. When the first cut core plate is stacked on the plurality of core pieces in the first process, the dowels of the first cut core plate are aligned with the dowels of the plurality of core pieces. When the second cut core plate is stacked on the first cut core plate in the second step, the dowels of the second cut core plate are aligned with the through holes of the first cut core plate. When multiple core pieces are stacked on the second cut core plate after the second step, the dowels of the core pieces are aligned with the dowels of the second cut core plate. The core forming step involves rolling multiple blocks so that the dowels of the first cut core plate of a block overlap with the dowels of the second cut core plate of a block other than the block, and then joining the multiple blocks together by crimping them with the dowels.

[0009] According to the above method, a first cut core plate and a second cut core plate are arranged at both ends of the blocks formed in the block forming process in the stacking direction of the core pieces. At this time, the dowels of the second cut core plate of one block are inserted into the through-holes of the first cut core plate of the other block. This prevents the adjacent blocks from joining together. In the core forming process, multiple blocks are rotated so that the dowels of the first cut core plate of one block overlap the dowels of the second cut core plate of another block. With the multiple blocks stacked in this manner in the direction of the center line of the core pieces, they are pressed so as to be compressed in the direction of the center line. As a result, the dowels of the second cut core plate and the dowels of the first cut core plate of adjacent blocks are crimped, thereby joining the stacked multiple blocks together. A motor core is then formed by joining the multiple blocks together. When forming the motor core in this manner, the multiple blocks can be joined together without welding. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 2 is a front view showing a stator core as a motor core. [Figure 2] 2 is a cross-sectional view showing the stator core as viewed in the direction of arrows II-II in FIG. 1. [Figure 3] 3 is a plan view showing core pieces forming a block of the stator core of FIG. 2. FIG. [Figure 4] 3 is a plan view showing a first cut core plate forming a block of the stator core of FIG. 2. FIG. [Figure 5] 3 is a plan view showing a second cut core plate forming a block of the stator core of FIG. 2. FIG. [Figure 6] FIG. 3 is a cross-sectional view showing a progressive press device for forming the block of FIG. 2. [Figure 7] FIG. 7 is a cross-sectional view showing a stacked state of blocks formed by the progressive press machine of FIG. 6. [Figure 8]FIG. 4 is a plan view showing a first cut core plate. [Figure 9] FIG. 10 is a plan view showing a second cut core plate. [Figure 10] 10 is a plan view showing the positional relationship between the first cut core plate and the second cut core plate shown in FIGS. 8 and 9. FIG. [Figure 11] 10 is a plan view showing the positional relationship between the first cut core plate and the second cut core plate shown in FIGS. 8 and 9. FIG. [Figure 12] FIG. 10 is a plan view showing another example of the first cut core plate. [Figure 13] FIG. 10 is a plan view showing another example of the second cut core plate. [Figure 14] 14 is a plan view showing the positional relationship between the first cut core plate and the second cut core plate shown in FIGS. 12 and 13. FIG. [Figure 15] 14 is a plan view showing the positional relationship between the first cut core plate and the second cut core plate shown in FIGS. 12 and 13. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0011] [First embodiment] A first embodiment of a method for manufacturing a motor core such as a stator core for a motor will be described below with reference to FIGS.

[0012] Fig. 1 shows the stator core as viewed in the direction in which its center line L1 extends, and Fig. 2 shows the stator core as viewed in the direction of arrows II-II in Fig. 1. As can be seen from Fig. 2, the stator core is formed by stacking multiple blocks 11 in the direction in which the center line L1 extends. Each block 11 includes core pieces 12, first cut core plates 13, and second cut core plates 14. The core pieces 12, first cut core plates 13, and second cut core plates 14 are formed by punching out from a thin sheet material.

[0013] The block 11 is formed by stacking iron core pieces 12, first cut core plates 13, and second cut core plates 14 in the direction in which the center line L1 extends. In the block 11, a large number of iron core pieces 12 are stacked in the direction in which the center line L1 extends. The first cut core plate 13 and the second cut core plate 14 are arranged at both ends in the stacking direction of the iron core pieces 12 in the block 11. The first cut core plate 13 is located in the bottom layer of the block 11 in FIG. 2. The second cut core plate 14 is located in the top layer of the block 11 in FIG. 2.

[0014] <Core piece 12> As shown in Fig. 3, the core piece 12 is in the shape of an annular plate having a center hole 20. A plurality of mounting holes 15 are formed on the outer edge of the core piece 12 at equal angular intervals centered on the center line L1. The mounting holes 15 are for fixing the stator core to the motor case with bolts or the like. In this example, three mounting holes 15 are formed in the core piece 12 at angular intervals of 120°.

[0015] A plurality of dowels 16 are formed on the circumference of the core piece 12 centered on the center line L1. The core pieces 12 in the block 11 are joined to one another by crimping the dowels 16. The dowels 16 are positioned at angular intervals of 30° around the center line L1. Therefore, the number of dowels 16 in the core piece 12 is 12. Furthermore, when the core piece 12 is divided into an odd number of areas A1 centered on the center line L1, more specifically, into a plurality of areas A1 having angles of 120°, four dowels 16 are positioned in each area A1.

[0016] <First cut core plate 13> As shown in Fig. 4, the first cut core plate 13 is in the shape of an annular plate having a center hole 20, similar to the core piece 12. Similar to the core piece 12, a plurality of mounting holes 15 are formed on the outer edge of the first cut core plate 13 at equal angular intervals centered on the center line L1. These mounting holes 15 play the same role as the mounting holes 15 of the core piece 12. The first cut core plate 13 has three mounting holes 15 formed at an angular interval of 120°.

[0017] A plurality of dowels 16 having the same shape as the dowels 16 of the core pieces 12 are formed on the circumference of the first cut core plate 13, centered on the center line L1, and a plurality of through holes 19 are also formed. The dowels 16 and the through holes 19 are located at 30° angular intervals around the center line L1. FIG. 4 shows the positional relationship between the dowels 16 and the through holes 19 in the regions A2 when the first cut core plate 13 is divided into odd-numbered regions, more specifically, regions A2 having 120° angular intervals, centered on the center line L1. As can be seen from FIG. 4, the through holes 19 of the first cut core plate 13 are formed at 90° intervals around the center line L1. Two dowels 16 are formed on the first cut core plate 13 between the through holes 19. The dowels 16 are located at equal intervals between each other and between the through holes 19.

[0018] <Second cut core plate 14> 5, the second cut core plate 14 is annular and has a central hole 20, similar to the core pieces 12 and the first cut core plate 13. Similar to the core pieces 12 and the first cut core plate 13, a plurality of mounting holes 15 are formed on the outer edge of the second cut core plate 14 at equal angular intervals centered on the center line L1. These mounting holes 15 play the same role as the mounting holes 15 of the core pieces 12 and the first cut core plate 13. The second cut core plate 14 has three mounting holes 15 formed at angular intervals of 120°.

[0019] A plurality of dowels 16 having the same shape as the dowels 16 of the core pieces 12 and the first cut core plate 13 are formed on the circumference of the second cut core plate 14, centered on the center line L1. A plurality of through holes 19 having the same shape as the through holes 19 of the first cut core plate 13 are also formed. The dowels 16 and through holes 19 are located at 30° angular intervals around the center line L1. Figure 5 shows the positional relationship between the dowels 16 and through holes 19 in the regions A3, when the second cut core plate 14 is divided into odd-numbered regions centered on the center line L1, more specifically, regions A3 at 120° angular intervals. As can be seen from Figure 5, the dowels 16 of the second cut core plate 14 are formed at 90° intervals around the center line L1. Two through holes 19 are formed in the second cut core plate 14, one between the dowels 16. The through holes 19 are located at equal intervals between each other and between the dowels 16.

[0020] When the first cut core plate 13 shown in Figure 4 and the second cut core plate 14 shown in Figure 5 are stacked in the thickness direction, the positional relationship between the dowel 16 and the through hole 19 is reversed in the areas A2 and A3 that overlap in the thickness direction.

[0021] Next, a progressive press device for forming the block 11 will be described. As shown in Figure 6, the progressive press device repeats mold closing, in which a movable table 32 positioned above a fixed table 31 approaches the fixed table 31, and mold opening, in which the movable table 32 moves away from the fixed table 31. A thin plate-shaped material 33 is transported between the fixed table 31 and the movable table 32. The material 33 is transported to the right in Figure 6 at a set pitch each time the progressive press device opens the mold.

[0022] A lower die set 34 and an upper die set 35 are provided facing each other on the fixed base 31 and the movable base 32. A stripper plate 36 is disposed below the upper die set 35 and is connected to the upper die set 35 via an elastic member. The stripper plate 36 is capable of moving vertically relative to the upper die set 35.

[0023] The progressive press device is provided with a first punching section 37, a press section 38, a second punching section 39, and a punching section 40 in this order from upstream to downstream in the conveying direction of the material 33. A distance corresponding to the pitch feed when conveying the material 33 is provided between each of the first punching section 37, the press section 38, the second punching section 39, and the punching section 40.

[0024] The first punching section 37, the press section 38, and the second punching section 39 are used to form the center hole 20, the dowel 16, the mounting holes 15, and the through holes 19 in the blank 33. The punching section 40 is used to punch out the core pieces 12, the first cut core plates 13, and the second cut core plates 14 from the blank 33. The progressive press device is equipped with a control device 21 that controls each section including the second punching section 39.

[0025] <First punched portion 37> The first piercing section 37 is equipped with a die 41 and a punch 42 for forming the center hole 20 in the blank 33. The die 41 is fixed to the lower die set 34 of the fixed table 31. The punch 42 is fixed to the upper die set 35 of the movable table 32. When the progressive press is closed, the punch 42 punches out a portion of the blank 33 that corresponds to the center hole 20, thereby forming the center hole 20 in the blank 33. After the center hole 20 is formed in this manner, when the progressive press is opened, the stripper plate 36 presses the blank 33 toward the die 41 to remove it from the punch 42. Furthermore, when the progressive press is opened, the blank 33 is transported downstream at the above-specified pitch feed.

[0026] <Press Department 38> The press unit 38 includes a die 43 and a punch 44 for forming dowels 16 in the material 33. The die 43 is fixed to the lower die set 34 of the fixed table 31. The punch 44 is fixed to the upper die set 35 of the movable table 32. The punches 44 are positioned corresponding to the dowels 16 of the core pieces 12 shown in FIG. 3. The die 43 and punch 44 shown in FIG. 6 form the dowels 16 in the material 33 by deforming the material 33 when the progressive press device is closed. After the dowels 16 are formed in this manner, when the progressive press device is opened, the stripper plate 36 presses the material 33 toward the die 41 to remove it from the punch 44. Furthermore, when the progressive press device is opened, the material 33 is transported downstream at the above-specified pitch feed.

[0027] <Second punched portion 39> The second punching section 39 is equipped with a die 45 and a punch 46 for forming the mounting holes 15 in the blank 33, and also with a die 47 and a punch 48 for forming the through holes 19 in the blank 33. The dies 45 and 47 are fixed to the lower die set 34 of the fixed base 31. The punch 46 is fixed to the upper die set 35 of the movable base 32. When the progressive press is closed, the punch 46 forms the mounting holes 15 in the blank 33 by punching out portions of the blank 33 that correspond to the mounting holes 15.

[0028] Furthermore, the punch 48 forms a through hole 19 in the blank 33 by punching a location corresponding to a predetermined one of the dowels 16 in the blank 33 during mold closing. The punch 48 is provided so as to be positioned corresponding to each of the dowels 16 in the blank 33. The punch 48 is fixed to a punching position that allows it to punch the blank 33 during mold closing, and is retracted into the upper die set 35 by releasing the fixation during mold closing so that it does not punch the blank 33. The fixation and release of the punch 48 are performed through control of the drive mechanism by the control device 21.

[0029] The control device 21 selectively forms the dowels 16 of the core pieces 12, the dowels 16 and through holes 19 of the first cut core plates 13, and the dowels 16 and through holes 19 of the second cut core plates 14 by fixing and releasing the punches 48 as described above when the molds are closed. In detail, the fixing and releasing of the punches 48 as described above when the molds are closed is performed in the following three patterns: (A), (B), and (C).

[0030] In pattern (A), the above-mentioned fixation of all punches 48 is released, so that the punches 48 do not punch out the blank 33 when the mold is closed. In this case, the punches 48 do not punch out the portions of the blank 33 corresponding to the dowels 16 when the mold is closed, so the dowels 16 in the blank 33 remain as dowels 16 in the core piece 12. The arrangement of the dowels 16 at this time is the same as the arrangement of the dowels 16 in the core piece 12 shown in FIG.

[0031] In pattern (B), the punches 48 corresponding to the through holes 19 of the first cut core plate 13 shown in FIG. 4 are fixed as described above, while the other punches 48 are released from fixation. In this case, when the mold is closed, the dowels 16 of the blank 33 that are located at positions corresponding to the through holes 19 of the first cut core plate 13 and their surroundings are punched out by the punch 48, thereby forming the through holes 19. On the other hand, the dowels 16 of the blank 33 that are not located at positions corresponding to the through holes 19 of the first cut core plate 13 and their surroundings are not punched out by the punch 48. Therefore, the dowels 16 remain as the dowels 16 of the first cut core plate 13. The arrangement of the dowels 16 and the through holes 19 at this time is the same as the arrangement of the dowels 16 and the through holes 19 of the first cut core plate 13 shown in FIG.

[0032] In pattern (C), the punches 48 corresponding to the through holes 19 of the second cut core plate 14 shown in FIG. 5 are fixed as described above, while the other punches 48 are released from fixation. In this case, when the mold is closed, the dowels 16 of the blank 33 that are located at positions corresponding to the through holes 19 of the second cut core plate 14 and their surroundings are punched out by the punch 48, thereby forming the through holes 19. On the other hand, the dowels 16 of the blank 33 that are not located at positions corresponding to the through holes 19 of the second cut core plate 14 and their surroundings are not punched out by the punch 48. Therefore, the dowels 16 remain as the dowels 16 of the second cut core plate 14. The arrangement of the dowels 16 and the through holes 19 at this time is the same as the arrangement of the dowels 16 and the through holes 19 of the second cut core plate 14 shown in FIG. 5.

[0033] When the control device 21 repeatedly closes and opens the progressive press, it repeats the above-mentioned fixing and releasing of the punch 48 in the order of one pattern (B), one pattern (C), and multiple patterns (A). As a result, the attachment hole 15 and the through hole 19 are formed in the material 33. When the progressive press opens, the stripper plate 36 shown in FIG. 6 presses the material 33 toward the dies 45, 47 so as to remove it from the punches 46, 48. Furthermore, when the progressive press opens, the material 33 is transported downstream at the above-mentioned set pitch feed.

[0034] <Punching section 40> The punching unit 40 includes a die 49, a squeeze ring 50, and a punch 51 for punching out and forming any one of the core pieces 12, the first cut core plate 13, and the second cut core plate 14 from the material 33. The die 49 is fixed to the lower die set 34 of the fixed base 31. The squeeze ring 50 is fixed to the lower side of the die 49 in the lower die set 34. The punch 51 is fixed to the upper die set 35 of the movable base 32. When the progressive press device is closed, the punch 46 punches out a portion of the material 33 that corresponds to the mounting hole 15, thereby forming any one of the core pieces 12, the first cut core plate 13, and the second cut core plate 14.

[0035] When the above-mentioned fixing and releasing of the punch 48 in the second punching section 39 is repeated in the above-mentioned pattern, the core pieces 12, the first cut core plate 13, and the second cut core plate 14 are formed in the punching section 40 as follows. That is, through punching the blank 33 with the punch 51 each time the mold is closed, the first cut core plate 13 is formed once, the second cut core plate 14 is formed once, and the core pieces 12 are formed multiple times. When the progressive press device is opened, the stripper plate 36 presses the blank 33 toward the die 49 so as to remove it from the punch 51.

[0036] Furthermore, the formed first cut core plate 13, second cut core plate 14, and core piece 12 are stacked in the thickness direction within the die 49 each time the mold is clamped, and are pressed downward toward the squeeze ring 50. At this time, as shown in FIG. 7 , the dowels 16 of the first cut core plate 13 overlap with the dowels 16 of the core piece 12 located below the first cut core plate 13. Furthermore, the dowels 16 of the second cut core plate 14 located above the first cut core plate 13 are inserted into the through holes 19 of the first cut core plate 13. Furthermore, the dowels 16 of the second cut core plate 14 overlap with the dowels 16 of the core piece 12 located above the second cut core plate 14. Furthermore, the dowels 16 of adjacent core pieces 12 also overlap with each other.

[0037] The first cut core plates 13, the second cut core plates 14, and the core pieces 12 stacked as described above are pressed downward each time the mold is closed, and reach the squeeze ring 50. The inner diameter of the squeeze ring 50 is slightly smaller than the inner diameter of the die 49. This makes it difficult for the first cut core plates 13, the second cut core plates 14, and the core pieces 12 to move downward once they reach the squeeze ring 50. As a result, the first cut core plates 13, the second cut core plates 14, and the core pieces 12 are compressed in the thickness direction as the mold is closed. This compression causes the dowels 16 of the first cut core plates 13, the second cut core plates 14, and the core pieces 12, which are stacked on top of each other, to be crimped.

[0038] By crimping the dowels 16 that are stacked on top of each other, a block 11 is formed in which a plurality of core pieces 12 are sandwiched between the first cut core plate 13 and the second cut core plate 14. In this block 11, the second cut core plate 14 is located in the lowest layer, and the first cut core plate 13 is located in the uppermost layer. Therefore, in adjacent blocks 11, the first cut core plate 13 of the block 11 located below is in contact with the second cut core plate 14 of the block 11 located above. Because the dowels 16 of the second cut core plate 14 are inserted into the through holes 19 of the first cut core plate 13, the adjacent blocks 11 are not joined together by crimping the dowels 16.

[0039] The formed block 11 is pressed downward each time the mold is closed, and is thereby extruded downward from within the squeeze ring 50. The extruded block 11 is transported by a transport device 52 located below the squeeze ring 50 for a post-process in which the block 11 is used to form a stator core.

[0040] Next, a method for manufacturing a stator core as a motor core will be described. This manufacturing method involves a block forming process in which the block 11 is formed using the progressive press machine described above, and a core forming process in which a stator core is formed by stacking and joining a plurality of blocks 11. The block forming process and the core forming process will be described in detail below.

[0041] <Block formation process> In this process, a first cut core plate 13, a second cut core plate 14, and a plurality of core pieces 12 are punched out from a blank 33 and then stacked in the thickness direction so that their dowels 16 overlap, thereby forming a block 11. In the block formation process, a first process of stacking a first cut core plate 13 on the plurality of core pieces 12 and a second process of stacking a second cut core plate 14 on the first cut core plate 13 are performed every time the core pieces 12 are stacked multiple times. These first and second processes are performed by a punching unit 40 of a progressive press machine. The first cut core plate 13 formed in the first process (shown in FIG. 4) and the second cut core plate 14 formed in the second process (shown in FIG. 5) are arranged at both ends in the stacking direction of the core pieces 12 in the block 11 formed through the first and second processes.

[0042] When the first cut core plate 13 formed in the first step and the second cut core plate 14 formed in the second step are divided into multiple regions having equal angles around the center line L1, the positional relationship between the dowels 16 and the through holes 19 is reversed in the regions that overlap in the thickness direction. As a result, when the first cut core plate 13 is stacked on the multiple core pieces 12 in the first step, the dowels 16 of the first cut core plate 13 are aligned with the dowels 16 of the multiple core pieces 12. When the second cut core plate 14 is stacked on the first cut core plate 13 in the second step, the dowels 16 of the second cut core plate 14 are aligned with the through holes 19 of the first cut core plate 13. When the multiple core pieces 12 are stacked on the second cut core plate 14 after the second step, the dowels 16 of the core pieces 12 are aligned with the dowels 16 of the second cut core plate 14.

[0043] Then, the first cut core plate 13, the second cut core plate 14, and the core pieces 12 are compressed in the thickness direction as the mold is clamped, and the dowels 16 that are stacked on top of each other are crimped. This crimping of the dowels 16 forms a block 11 in which multiple core pieces 12 are sandwiched between the first cut core plate 13 and the second cut core plate 14. Adjacent blocks 11 formed by the punching section 40 of the progressive press device are not joined to each other. This is because the dowel 16 of the second cut core plate 14 in the upper block 11 of adjacent blocks 11 is inserted into the through hole 19 of the first cut core plate 13 in the lower block 11.

[0044] <Core formation process> In this step, a plurality of blocks 11 are stacked in a rotational manner so that the dowels 16 of the first cut core plates 13 in one block 11 overlap with the dowels 16 of the second cut core plates 14 in another block 11 different from the block 11.

[0045] Specifically, the block 11 formed by the progressive press is turned upside down so that the first cut core plate 13 is on top. Then, another block 11 is placed on top of the block 11. The other block 11 is also turned upside down so that the first cut core plate 13 is on top. Furthermore, the other block 11 is rotated around the center line L1 so that the dowels 16 of the second cut core plate 14 overlap with the dowels 16 of the block 11 below. The rotation of the other block 11 is the angle that defines the regions A1 to A3, i.e., 120°.

[0046] FIG. 2 shows a state in which the blocks 11 are stacked along the direction of the center line L1 by continuing the above-described rolling of the blocks 11. The number of blocks 11 required to form the stator core is stacked. The multiple blocks 11 stacked in this manner are pressed by a pressing device so as to be compressed in the direction of the center line L1. This strengthens the joint between the dowels 16 of each core piece 12 in the blocks 11 by crimping. At this time, the dowels 16 of the second cut core plates 14 and the dowels 16 of the first cut core plates 13 of adjacent blocks 11 are crimped, so that the stacked multiple blocks 11 are joined together. Then, the stator core is formed by joining the multiple blocks 11 together.

[0047] Next, the effects of the above-described method for manufacturing a stator core will be described. (1-1) A first cut core plate 13 and a second cut core plate 14 are arranged at both ends in the stacking direction of the core pieces 12 in the blocks 11 formed in the block forming process. At this time, between adjacent blocks 11, the dowel 16 of the second cut core plate 14 in one block 11 is inserted into the through hole 19 of the first cut core plate 13 in the other block 11. This prevents the adjacent blocks 11 from joining together.

[0048] In the core forming process, multiple blocks 11 are stacked in a rotated manner so that the dowels 16 of the first cut core plates 13 in one block 11 overlap the dowels 16 of the second cut core plates 14 in another block 11. With the multiple blocks 11 stacked in this manner in the direction in which the center lines L1 of the core pieces 12 extend, they are pressed so as to be compressed in the direction in which the center lines L1 extend. More specifically, in order to strengthen the joints between the dowels 16 of the core pieces 12 of the stacked multiple blocks 11 by crimping, the multiple blocks 11 are pressed in the direction in which the center lines L1 extend through a pressing process using a pressing device.

[0049] At this time, the dowels 16 of the second cut core plates 14 and the dowels 16 of the first cut core plates 13 of adjacent blocks 11 are crimped together, so that the stacked blocks 11 are joined together. The stator core is then formed by joining the blocks 11 together. In this way, when forming the stator core, the blocks 11 can be joined together without welding.

[0050] (1-2) When the second cut core plate 14 and the first cut core plate 13 of the block 11 formed in the block forming process are divided into a plurality of regions having equal angles around the center line L1, the positional relationship between the dowels 16 and the through holes 19 is reversed in the regions that overlap in the thickness direction. Then, in the core forming process, the block 11 after the block forming process is rotated around the center line L1 of the core pieces 12 by an angle that defines the above-mentioned region. This causes the dowels 16 of the second cut core plate 14 of the above-mentioned block 11 to overlap with the dowels 16 of the first cut core plate 13 of another block 11 adjacent to the above-mentioned block 11. Therefore, when a plurality of blocks 11 are stacked in the direction extending along the center line L1 in the core forming process, the dowels 16 of adjacent blocks 11 tend to overlap as described above.

[0051] (1-3) The angle defining the above region is 120°. The through holes 19 of the first cut core plate 13 are formed at 90° intervals around the center line L1. Two dowels 16 of the first cut core plate 13 are formed between the through holes 19. The dowels 16 of the first cut core plate 13 are positioned at equal intervals between each other and between the through holes 19. The dowels 16 of the second cut core plate 14 are formed at 90° intervals around the center line L1. Two through holes 19 of the second cut core plate 14 are formed between the dowels 16. The through holes 19 of the second cut core plate 14 are positioned at equal intervals between each other and between the dowels 16. Then, in the core forming process, the block 11 is rotated by 120° around the center line L1 of the core pieces 12 as the rotation of the block 11 in the block forming process. As a result, the dowels 16 of the second cut core plate 14 of the block 11 overlap with the dowels 16 of the first cut core plate 13 of another block 11 adjacent to the block 11 at four locations around the center line L1. These four locations correspond to four dowels 16 spaced at equal angular intervals among the dowels 16 in Fig. 1. Since the multiple blocks 11 are joined to each other at these four locations by crimping the dowels 16, the joining of the blocks 11 can be made strong.

[0052] [Second embodiment] Next, a second embodiment of a method for manufacturing a motor core such as a stator core will be described with reference to FIGS.

[0053] This embodiment differs from the first embodiment in that when the first cut core plate 13 and the second cut core plate 14 are divided into a plurality of regions having equal angles around the center line L1, the number of regions is even, and the angle is 90°. More specifically, by setting the angle to 90°, the plurality of regions are divided into four regions.

[0054] As shown in Figure 8, the first cut core plate 13 has four regions A2. The first cut core plate 13 has four mounting holes 15, each at equal angular intervals, specifically 90°, centered on the center line L1. The total number of dowels 16 and through holes 19 in the first cut core plate 13 within the region A2 is odd, and they are alternately formed at equal angular intervals around the center line L1. In this example, the total number of dowels 16 and through holes 19 within the region A2 is three, and the first cut core plate 13 as a whole has six dowels 16 and six through holes 19.

[0055] As shown in Figure 9, the second cut core plate 14 has four regions A3. The second cut core plate 14 has four mounting holes 15 formed at equal angular intervals, specifically, 90°, around the center line L1. The total number of dowels 16 and through holes 19 in the second cut core plate 14 within the region A3 is an odd number, the same as the first cut core plate 13, and they are alternately formed at equal angular intervals around the center line L1. In this example, the total number of dowels 16 and through holes 19 in the region A3 is three, and the second cut core plate 14 as a whole has six dowels 16 and six through holes 19.

[0056] There are also four regions A1 of the core piece 12. The dowels 16 of the core piece 12 are formed at equal angular intervals around the center line L1. The number of dowels 16 in the core piece 12 is 12. Four mounting holes 15 of the core piece 12 are also formed at equal angular intervals, specifically, at 90° intervals, centered on the center line L1.

[0057] Fig. 10 shows the positional relationship around the center line L1 between the first cut core plate 13 and the second cut core plate 14 formed in the block forming process. Fig. 11 shows the positional relationship between the first cut core plate 13 and the second cut core plate 14 that contact each other in adjacent blocks 11 when the stator core is formed in the core forming process.

[0058] In this embodiment, in addition to the effects (1-1) and (1-2) in the first embodiment, the following effects can be obtained. (2-1) The first cut core plate 13 punched out of the blank 33 in the first step of the block forming process and the second cut core plate 14 punched out of the blank 33 in the second step have the same shape, including the dowels 16 and the through holes 19. However, the first cut core plate 13 and the second cut core plate 14 punched out of the blank 33 in the block forming process are positioned with an angle offset that defines the above-mentioned regions A2 and A3 in the rotation direction about the center line L1 of the core pieces 12. Therefore, in the core forming process, the block after the block forming process is rotated around the center line L1 of the core pieces 12 by the above-mentioned angle, i.e., 90°. This allows the dowels 16 of the second cut core plate 14 of the block 11 to overlap with the dowels 16 of the first cut core plate 13 of another block 11 adjacent to the block 11. Then, multiple blocks 11 can be joined together by caulking the dowels 16.

[0059] [Other embodiments] The above-described embodiments can be modified, for example, as follows: The above-described embodiments and the following modifications can be combined with each other within the scope of technical compatibility.

[0060] In the second embodiment, the numbers of the dowels 16 and the through holes 19 in the first cut core plate 13 and the second cut core plate 14 may be changed as appropriate. For example, as shown in Figures 12 and 13, the number of dowels 16 and the number of through holes 19 in the first cut core plate 13 may both be two, and the number of dowels 16 and the number of through holes 19 in the second cut core plate 14 may both be two.

[0061] In this case, the positional relationship around the center line L1 between the first cut core plate 13 and the second cut core plate 14 formed in the block forming process is as shown in Figure 14. Furthermore, the positional relationship between the first cut core plate 13 and the second cut core plate 14 that contact each other in adjacent blocks 11 when the stator core is formed in the core forming process is as shown in Figure 15.

[0062] A rotor core may be manufactured as the motor core instead of a stator core. [Explanation of symbols]

[0063] 11...Block 12...Iron core piece 13...First cut core plate 14...Second cut core plate 15...Mounting hole 16...Dowel 19...Through hole 20…Center hole 21...Control device 31…Fixed stand 32…Movable base 33...Material 34...Lower die set 35...Upper die set 36...Stripper plate 37...First punched hole 38...Press Department 39...Second hole punching section 40...Punching section 41...Die 42...Punch 43...Die 44...Punch 45...Die 46...Punch 47...Die 48...Punch 49...Die 50...Squeeze ring 51...Punch 52...Transportation device

Claims

1. A method for manufacturing a motor core includes a block forming step of punching out core pieces having dowels from a thin plate-like material and stacking the core pieces so that the dowels are overlapped to form a block, and a core forming step of stacking and joining a plurality of the blocks to form a motor core, The block forming process includes a first process of punching out a first cut core plate having dowels and through holes from the material and stacking it on the plurality of iron core pieces, and a second process of punching out a second cut core plate having dowels and through holes from the material and stacking it on the first cut core plate, each time the iron core pieces are stacked multiple times, thereby arranging the first cut core plate and the second cut core plate at both ends of the stacking direction of the iron core pieces in the block, When the first cut core plate is stacked on the plurality of iron core pieces in the first step, the dowels of the first cut core plate are aligned with the dowels of the plurality of iron core pieces, When the second cut core plate is stacked on the first cut core plate in the second step, the dowels of the second cut core plate are aligned with the through holes of the first cut core plate, When the plurality of iron core pieces are stacked on the second cut core plate after the second step, the dowels of the iron core pieces are aligned with the dowels of the second cut core plate, The core forming process involves stacking multiple blocks so that the dowels on the first cut core plate of one block overlap with the dowels on the second cut core plate of another block, and then joining the multiple blocks together by crimping the dowels in that state.This is a manufacturing method for a motor core.

2. The dowels and through holes of the first cut core plate and the dowels and through holes of the second cut core plate are formed at equal angular intervals around the center line of the block, When the first cut core plate formed in the first step and the second cut core plate formed in the second step are each divided into a plurality of regions having equal angles around the center line, the positional relationship between the dowels and the through holes is reversed in the regions that overlap in the thickness direction, 2. The motor core manufacturing method of claim 1, wherein in the core forming process, the block is rotated after the block forming process by rotating the block around the center line of the block by an angle that defines the region so that the dowels of the first cut core plate of the block overlap with the dowels of the second cut core plate of the other block.

3. The method for manufacturing a motor core according to claim 2 , wherein the plurality of regions are an odd number of regions having equal angles around the center line.

4. the angle defining said region is 120°; The through holes of the first cut core plate are formed at 90° intervals around the center line, Two dowels are formed in the first cut core plate between the through holes, and are positioned at equal intervals between each other and between the through holes; The dowels of the second cut core plate are formed at 90° intervals around the center line, 4. The method for manufacturing a motor core according to claim 3, wherein two through holes are formed in the second cut core plate between the dowels, and the through holes are positioned at equal intervals between each other and between the dowels.

5. The method for manufacturing a motor core according to claim 2 , wherein the plurality of regions is an even number of regions having equal angles around the center line.

6. the angle defining the region is 90°; The total number of dowels and through holes in the first cut core plate within the region is odd, and the dowels and through holes are alternately formed at equal angular intervals around the center line, 6. A motor core manufacturing method as described in claim 5, wherein the total number of dowels and through holes of the second cut core plate within the region is the same odd number as that of the first cut core plate, and the dowels and through holes are alternately formed at equal angular intervals around the center line.

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