Method for manufacturing laminated iron core and dummy block

Abstract

The purpose of the present invention is to provide a method for manufacturing a laminated iron core with which it is possible to more reliably perform mutual fastening of iron core pieces. When laminating a plurality of iron core pieces 25 in a die 3 by sequentially punching and holding an iron core piece 25 from a steel plate 16 using a punch 1 and a die 3, the dummy block 9 is held in advance in the die 3 by friction, and while receiving the plurality of iron core pieces 25 on the dummy block 9, the adjacent iron core pieces 25 are connected by caulking, and frictional force for holding the dummy block 9 is set by an adjustment mechanism 13 provided in the dummy block 9.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a laminated core of a rotating electric machine and a dummy block used therefor.

Background Art

[0002] As a conventional method for manufacturing a laminated core, there is one that uses a dummy block as described in Patent Document 1.

[0003] In this method for manufacturing a laminated core, a dummy block is previously placed in a die, and the dummy block is held in a squeeze ring by frictional force. In this state, a plurality of core pieces are sequentially punched out and held in the die, so that the plurality of core pieces can be received on the dummy block and adjacent core pieces can be integrated by fastening such as caulking.

[0004] Therefore, even when no core pieces are held in the die, for example, after maintenance of a punch or a die, adjacent core pieces of the plurality of core pieces can be securely fastened.

[0005] However, in such a manufacturing method, if the frictional force of the dummy block against the squeeze ring is not set appropriately, incomplete fastening is likely to occur. Further, although the dummy block is reused, it becomes difficult to maintain an appropriate frictional force due to wear, and in this case, there is also a problem of causing incomplete fastening.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] The problem to be solved is that when using a dummy block, it is likely to cause a connection due to incomplete fastening. [Means for solving the problem]

[0008] The present invention provides a method for manufacturing laminated iron cores, wherein a dummy block is held by frictional force within a die that punches out iron core pieces from a steel plate in cooperation with a punch, a plurality of iron core pieces are sequentially punched out from the steel plate by the punch and the die, the punched iron core pieces are sequentially held within the die and stacked, the dummy block receives the punched iron core pieces when stacking the punched iron core pieces within the die and fastens adjacent iron core pieces to the punched iron core pieces, and the frictional force for holding the dummy block within the die is set by an adjustment mechanism provided in the dummy block.

[0009] The present invention provides a dummy block used when sequentially punching out a plurality of core pieces from a steel plate using a punch and die, and sequentially holding the punched core pieces in the die and stacking them, comprising: a block body that is held in the die by frictional force and receives the punched core pieces and fastens adjacent core pieces to the punched core pieces; and an adjustment mechanism for setting the frictional force for holding the block body in the die. [Effects of the Invention]

[0010] In this invention, a dummy block can be used to enable more proper fastening. [Brief explanation of the drawing]

[0011] [Figure 1] Figure 1 is a cross-sectional view showing a manufacturing apparatus for laminated iron cores using a dummy block according to Embodiment 1 of the present invention. [Figure 2] Figure 2 is a plan view of the manufacturing apparatus for the laminated iron core shown in Figure 1. [Figure 3] Figure 3 is a cross-sectional view of the dummy block in Figure 2, taken along line III-III. [Figure 4] Figure 4 is an enlarged plan view of a portion of the dummy block in Figure 3. [Figure 5]FIG. 5 is a cross-sectional view showing a part of the laminated core of Example 1. [Figure 6] FIG. 6 is a plan view of the dummy block according to Example 2 of the present invention. [Figure 7] FIG. 7 is a cross-sectional view of the manufacturing apparatus of the laminated core corresponding to line VII-VII of FIG. 6. [Figure 8] FIG. 8 is a plan view of the dummy block according to a modification of Example 2. [Figure 9] FIG. 9 is a cross-sectional view of the manufacturing apparatus of the laminated core corresponding to line IX-IX of FIG. 8. [Figure 10] FIG. 10 is a plan view showing the dummy block according to Example 3 of the present invention. [Figure 11] FIG. 11 is a cross-sectional view taken along line XI-XI of FIG. 10. [Figure 12] FIG. 12 is a cross-sectional view taken along line XII-XII of the dummy block of FIG. 10. [Figure 13] FIG. 13 is a cross-sectional view showing the dummy block according to Example 4 of the present invention. [Figure 14] FIG. 14 is a plan view of the dummy block of FIG. 13. [Figure 15] FIG. 15 is a cross-sectional view showing the relationship between the dummy block and the squeeze ring according to Example 5 of the present invention. [Figure 16] FIG. 16 is a plan view showing the dummy block and the squeeze ring of FIG. 15. [Figure 17] FIG. 17 is a cross-sectional view showing the relationship between the dummy block and the squeeze according to a modification of Example 5.

BEST MODE FOR CARRYING OUT THE INVENTION

[0012] The manufacturing method of the laminated core of one embodiment holds the dummy block 9 by friction in the die 3 that punches out the core piece 25 from the steel plate 16 in cooperation with the punch 1. Then, a plurality of core pieces 25 are sequentially punched out from the steel plate 16 by the punch 1 and the die 3, and the punched core pieces 25 are sequentially held in the die 3 and laminated. When laminating the punched core pieces 25 in the die 3, the core piece 25 punched on the dummy block 9 is received, and the adjacent core pieces 25 of the punched core piece 25 are fastened. The frictional force for holding the dummy block 9 in the die 3 is set by the adjustment mechanism 13 provided in the dummy block 9.

[0013] As one embodiment, the frictional force may be set by the pressing of the engagement screw 15 provided in the adjustment mechanism 13 with respect to the die 3.

[0014] As another embodiment, the frictional force is set by the pressing of the pressing members 51 and 63 provided in the adjustment mechanism 13 with respect to the die 3, and the pressing members 51 and 63 may be moved by the drive screws 41 and 53 or biased by the biasing member 63.

[0015] As another embodiment, the frictional force is set by the pressing of the movable parts 37 and 39 provided in the dummy block 9 with respect to the die 3, and the movable parts 37 and 39 may be moved by the drive screw 41 provided in the adjustment mechanism 13.

[0016] A plurality of dummy blocks 9 may be laminated according to the thickness of the laminated core, and at least the dummy blocks 9 at both ends in the lamination direction may be fastened.

[0017] As another embodiment, a plurality of dummy blocks 9 may be laminated according to the thickness of the laminated core, and the adjacent dummy blocks 9 in the laminated dummy blocks 9 may be joined.

[0018] The dummy block 9 may be held either by the friction between the outer periphery and the die 3 or by the friction between the inner periphery and the press-fit bar disposed in the die 3.

Example

[0019] [Laminated Iron Core Manufacturing Equipment] Figure 1 is a cross-sectional view showing a manufacturing apparatus for laminated iron cores using a dummy block according to Embodiment 1 of the present invention. Figure 2 is a plan view of the manufacturing apparatus for laminated iron cores shown in Figure 1.

[0020] The laminated core manufacturing apparatus shown in Figures 1 and 2 is, for example, a manufacturing apparatus for laminated cores used as motor cores in rotating electric machines, and has a punch 1 and a die 3 that works in cooperation with the punch 1 to punch out core pieces 25 from a steel plate 16. The die 3 in this embodiment comprises a die body 4 and a squeeze ring 7 supported by a die holder 5.

[0021] The die body 4 is ring-shaped and has a circular inner circumference. Together with the rising and falling punch 1, the die body 4 sequentially punches out disc-shaped iron core pieces 25 from a strip-shaped steel sheet 16 such as an electromagnetic steel sheet or a silicon steel sheet.

[0022] The squeeze ring 7 is formed in a ring shape that is longer in the punching direction than the die body 4 and has a planar circular inner circumference. The punching direction coincides with the stacking direction of the iron core pieces 25 and the dummy block 9. The squeeze ring 7 is positioned adjacent to the die body 4 in the punching direction of the iron core pieces 25. The inner diameter of the squeeze ring 7 is slightly smaller than the inner diameter of the die body 4.

[0023] The squeeze ring 7 is the part that applies lateral pressure to hold the punched iron core piece 25 by pressing it from the outer circumference. It is also possible to omit the squeeze ring 7. In this case, the die body 4 can be extended in the punching direction, or the die holder 5 can be reduced in diameter to provide the function of the squeeze ring 7.

[0024] The dummy block 9 is held inside the die 3 by frictional force. The dummy block 9 is held inside the die 3 when there are no previously punched iron core pieces 25 inside the die 3, and it sequentially receives and stacks the punched iron core pieces 25.

[0025] In this embodiment, four layers of dummy blocks 9 are pre-held within the die 3. The total thickness of the four layers of dummy blocks 9 is the same as the thickness of the motor core as a laminated iron core. The thickness of each dummy block 9 is the same as that of a block formed by laminating a predetermined number of iron core pieces 25. Multiple blocks, four in this embodiment, are laminated and integrated to form the motor core.

[0026] The number of dummy blocks 9 can be arbitrary, as long as the iron core pieces 25 can be joined together by crimping. For example, it is possible to hold two layers of dummy blocks 9, or to set the thickness of multiple layers or one layer of dummy blocks 9 to 90% of the thickness of the motor core.

[0027] Figure 3 is a cross-sectional view of the dummy block in Figure 2 along line III-III. Figure 4 is an enlarged plan view of a portion of the dummy block in Figure 3.

[0028] As shown in Figures 1 to 3, each dummy block 9 comprises a block body 10 and an adjustment mechanism 13. The block body 10 is formed in the shape of a disc or cylinder made of resin or the like. This block body 10 is held in place by frictional force within the die 3 and receives the punched iron core pieces 25, fastening adjacent iron core pieces 25 together. The planar shape of the block body 10 can be arbitrarily set, but it is preferable to make it circular in order to receive the disc-shaped iron core pieces 25. The material of the block body 10 can also be arbitrary, but a lightweight material such as resin is suitable.

[0029] The outer diameter of the block body 10 is set to be slightly smaller than the inner diameter of the die body 4. The block body 10 is equipped with an adjustment mechanism 13.

[0030] The adjustment mechanism 13 sets the frictional force for holding the block body 10 within the die 3. The adjustment mechanism 13 in this embodiment is equipped with an engagement screw 15. The engagement screw 15 is, for example, a bolt made of resin. The fact that the engagement screw 15 is made of resin helps to suppress damage to the die body 4 and the squeeze ring 7. The engagement screw 15 is positioned from a hole 17 formed in the block body 10 of the dummy block 9 to the outer circumference of the block body 10.

[0031] The holes 17 are arranged at 90° intervals, for example, at four locations around the circumferential direction of the block body 10. The number and arrangement of the screw holes 17 can be arbitrarily set. Depending on the number and arrangement of the screw holes 17, the number and arrangement of the engaging screws 15 in the circumferential direction can also be arbitrarily set. Furthermore, the number and arrangement of the engaging screws 15 in the stacking direction can also be arbitrarily set. For example, the dummy blocks 9 from the second layer onwards may be configured without engaging screws 15. Dummy blocks 9 (block body 10) without engaging screws 15 can also be in a simple disc shape.

[0032] The screw head 15a of the engaging screw 15 is located in each hole 17, and the threaded portion 15b of the engaging screw 15 is screwed into a screw hole 10a provided along the radial direction of the block body 10. The screw hole 10a may also be provided along a direction intersecting the radial direction.

[0033] The tip of the threaded portion 15b of the engaging screw 15 protrudes from the outer surface of the dummy block 9 and frictionally engages with the inner surface of the squeeze ring 7. The tip surface of the threaded portion 15b of the engaging screw 15 is flat, but it can also be curved to conform to the inner surface of the squeeze ring 7.

[0034] The frictional force between the die 3 of the dummy block 9 and the squeeze ring 7 is set by pressing the engagement screw 15 against the die body 4. The engagement screw 15 is pressed by manipulating the screw head 15a of the engagement screw 15 with a tool inserted into the hole 17.

[0035] In this embodiment, as shown in Figure 4, a collar 19 is added to set the pressing force. The collar 19 is interposed between the screw head 15a of the engaging screw 15 and the inner surface of the hole 17. When the screw head 15a is tightened against the inner surface of the hole 17, the length of the threaded portion 15b protruding from the outer surface of the dummy block 10 is set by the collar 19.

[0036] [Manufacturing method for laminated iron cores] Figure 5 is a cross-sectional view showing a portion of the laminated iron core of Example 1.

[0037] In the manufacturing method of the laminated core of this embodiment, a strip-shaped steel sheet 16 is sent to a mold device and, after undergoing a predetermined pressing process to form a motor core shape, the outer shape is punched out as shown in Figure 1. In this outer shape punching, a punch 1 and a die 3 sequentially punch out multiple core pieces 25 from the steel sheet 16, and the punched core pieces 25 are sequentially held in the die 3 and laminated. In this way, a motor core, which is a laminated core of a predetermined thickness, is manufactured.

[0038] In this embodiment, blocks with a stacking height lower than the motor core are formed, and multiple blocks are stacked with alternating phases. However, the stacking may be done with alternating phases for each core piece 25, or the core pieces 25 may be stacked without altering the phases.

[0039] In the punching of the outer shape, as shown in Figure 1, the dummy block 9 is used when there are no previously punched iron core pieces 25 inside the die 3, such as after maintenance of the punch 1 or die 3. In this embodiment, four layers of dummy block 9 are used.

[0040] Each dummy block 9 is inserted into the die body 4 with the engagement screw 15 loosened. Then, by tightening the engagement screw 15, the tip of the threaded portion 15b of the engagement screw 15 protrudes from the outer circumference of the dummy block 9 by a set length. The protruding length of this threaded portion 15b is such that the dummy block 9 frictionally engages with the inner diameter of the squeeze ring 7, which is slightly smaller than the inner diameter of the die body 4, with a set frictional force. This setting is performed by rotating the screw head 15a with a tool through the hole 17 in the block body 10.

[0041] In this way, the dummy block 9 is positioned within the die body 4 to match the protrusion amount of the tip of the engaging screw 15, and in that state, is pressed into the smaller diameter squeeze ring 7. The pressing is performed by driving the dummy block 9, with the engaging screw 15 tightened, out of the die body 4 with a hammer or the like.

[0042] At this time, the horizontality of the surface of the dummy block 9 in the direction perpendicular to the stacking direction does not need to be precise. Even if it is driven in at a slight angle, the surface of the dummy block 9 will conform to the punch 1 when the first iron core piece 25 is punched out onto the dummy block 9. In this way, the dummy block 9 is held in place within the die 3 by frictional force.

[0043] During the punching of the iron core piece 25, the processed strip-shaped steel plate 16 is transferred onto the die 3, and the upper die stripper (not shown) holds down the steel plate 16 while the punch 1 punches out the outer circumference.

[0044] The iron core piece 25, which is first punched into the die 3, is received by the punch 1 so as to be pressed onto the dummy block 9 at the upper end. At this time, the dummy block 9 can reliably receive the iron core piece 25 with frictional reaction force. The frictional reaction force of the dummy block 9 is mainly generated by the dummy block 9 located within the squeeze ring 7.

[0045] When the second layer of core piece 27 is punched out, it is stacked on top of the first core piece 25 and received on the dummy block 9. As a result, the dummy block 9 descends inside the die 3 due to the thickness of the core piece 25.

[0046] At this time, as shown in Figure 5, the protrusion of the crimping portion 23 of the second layer core piece 27 fits into the crimping hole 21 of the bottom layer core piece 25. This fitting is ensured by the core piece 25 being supported on the dummy block 9 and pressed by the punch 1. In this way, the first and second layer core pieces 25, which are adjacent to each other, are fastened together by the crimping portion 23 and the crimping hole 21.

[0047] Note that the crimping holes 21 and crimping portions 23 in Figure 5 are formed by a pressing process before punching out the outer circumference. The crimping holes 21 and crimping portions 23 are just one example of fastening, and other shapes are also possible. The bottommost iron core piece 25 has crimping holes 21 formed in it, and the iron core pieces 27 that are sequentially stacked on the bottommost iron core piece 25 have crimping portions 23 formed on them, with one side being a convex portion and the other side being a concave portion.

[0048] When the third iron core piece 27 is punched out in the same way, it is stacked on top of the second iron core piece 25 and received on the dummy block 9. As a result, the dummy block 9 descends further within the die 3 according to the thickness of the iron core piece 25, and the protrusion of the crimping portion 23 of the third iron core piece 25 fits into the recess of the crimping portion 23 of the second iron core piece 25. In this way, the adjacent iron core pieces 25, the second and third iron core pieces 25, are fastened together by the crimping portion 23.

[0049] Similarly, a predetermined number of core pieces 25 are stacked and adjacent core pieces 25 are fastened together. The dummy block 9 can be started at any appropriate timing; for example, it may start when the first core piece 25 is punched out, or it may start when several pieces are punched out after the first.

[0050] In this manufacturing method, the dummy blocks 9 pass through the squeeze ring 7 and then fall sequentially due to their own weight. The fallen dummy blocks 9 are then pushed radially out by a pusher (not shown) or the like and transported away. The dummy blocks 9 are then prepared for repeated use.

[0051] The removal of the dummy block 9 is automated based on the manufacturing program for the laminated iron core, and if the thickness of the dummy block 9 is the same as the thickness of the block, smooth operation is possible until removal.

[0052] As described above, a dummy block 9 is used in the manufacturing method of the laminated iron core, and this dummy block 9 is equipped with an adjustment mechanism 13. The frictional force for holding the dummy block 9 inside the die 3 is set by the adjustment mechanism 13.

[0053] Therefore, the adjustment mechanism 13 allows for easy and reliable setting of the frictional force of the dummy block 9, enabling more appropriate crimping and joining of the iron core pieces 25.

[0054] In this embodiment, the frictional force is set by pressing the engaging screw 15 against the die 3, which can be done easily and reliably, and repeated resetting is also easy. Furthermore, the dummy block 9 is pressed into the smaller diameter squeeze ring 7 by aligning the amount of protrusion of the tip of the threaded portion 15b of the engaging screw 15 with the die body 4, thus making it easy to hold the die 3 by friction.

[0055] The dummy block 9 has a thickness corresponding to the blocks that make up the laminated core, and since multiple dummy blocks are stacked according to the thickness of the laminated core, it can be discharged using the same process as the laminated core by the laminated core production program.

[0056] Since the engaging screw 15 is made of resin, it allows for smooth movement between the die body 4 and the squeeze ring 7, and also helps to prevent damage to the die body 4 and the squeeze ring 7. [Examples]

[0057] Figure 6 is a plan view showing a dummy block according to Example 2. Figure 7 is a cross-sectional view of the laminated core manufacturing apparatus corresponding to line VII-VII in Figure 6. Note that Example 2 has the same basic configuration as Example 1, and the same or corresponding components as in Example 1 are indicated by the same reference numerals, and redundant explanations are omitted.

[0058] As shown in Figures 6 and 7, in the manufacturing method of the laminated iron core of Example 2, the dummy block 9 has a thickness corresponding to the block that constitutes a part of the lamination direction of the motor core, similar to Example 1, and multiple dummy blocks 9, for example four, are laminated according to the thickness of the motor core. The four laminated layers of dummy blocks 9 are joined to each other by fixing screws 29 which act as fasteners.

[0059] For the four layers of dummy blocks 9, relief holes 33 and screw holes 35 with counterbores 31 are formed so as to penetrate in the stacking direction. These relief holes 33 and screw holes 35 are formed on intersecting diameters (orthogonal diameters in this embodiment) in each dummy block 9 and are arranged on the same virtual circle.

[0060] The four layers of dummy blocks 9 are circumferentially offset in phase so that the screw holes 35 of the lower layer are concentric with the relief holes 33 of the upper layer. These four layers of dummy blocks 9 are inserted into the die 3 in order, starting with the bottommost layer, the first layer of dummy blocks 9.

[0061] Specifically, the first dummy block 9 is inserted into the die body 4, the engaging screw 15 is adjusted, and then it is press-fitted into the squeeze ring 7. Next, the second dummy block 9 is placed on top of the first dummy block 9 with a different phase, and both dummy blocks 9 are fastened together with fixing screws 9.

[0062] After this fastening, the second dummy block 9 is pressed into the squeeze ring 7. Similarly, the third and fourth dummy blocks 9 are sequentially stacked and fastened, and the four layers of dummy blocks 9 are placed together as a single unit inside the die 3 as shown in Figure 7.

[0063] Therefore, in this embodiment, even when multiple dummy blocks 9 are stacked and integrated to have the same thickness as the motor core, they can be reliably placed inside the die 3 while appropriately adjusting the frictional force of each layer of dummy blocks 9.

[0064] Furthermore, the work performed on each dummy block 9 using the engaging screws 15 and fixing screws 29 can be carried out near the surface of the die 3, thereby improving work efficiency. Note that the fixing of the dummy blocks 9 with the fixing screws 29 may be performed on only some of the dummy blocks 9 among the multiple layers of dummy blocks 9.

[0065] The dummy block 9 can be pressed into the die 3 by pressing it in sequentially from the surface of the die 3, enabling easy and reliable press-fitting of the dummy block 9.

[0066] Furthermore, the same effects and advantages as in Example 1 can be achieved in this Example 2.

[0067] [Differentiation] Figure 8 is a plan view showing a dummy block according to a modified example of Example 2. Figure 9 is a cross-sectional view of the manufacturing apparatus for laminated iron cores corresponding to line IX-IX in Figure 8.

[0068] In the modified examples shown in Figures 8 and 9, the dummy blocks 9 at both ends in the stacking direction of the four stacked layers of dummy blocks 9 are fastened together.

[0069] In other words, in the four layers of dummy blocks 9, the phase of the relief holes 33 and screw holes 35 is shifted between the first layer of dummy blocks 9 and the second to fourth layers of dummy blocks 9. In the second to fourth layers of dummy blocks 9, the phase of the relief holes 33 and screw holes 35 is aligned.

[0070] The fixing screw 29 is screwed into the threaded hole 35 of the first dummy block 9 through the relief hole 33 of the 4th to 2nd layers, via the counterbore 31 on the surface of the 4th layer dummy block 9. This allows the dummy blocks 9 between the 1st and 4th layers at both ends to be fastened in the stacking direction. For the 2nd and 3rd layer dummy blocks 9, the fixing screw 29 is simply inserted through them, and there is no screwing of the fixing screw 29.

[0071] However, the four layers of dummy blocks 9 only need to be fastened and fixed at least between both ends in the stacking direction, and it is also acceptable for only the second layer of dummy blocks 9 or only the third layer of dummy blocks 9 to not have the fixing screws 29 threaded into them.

[0072] In Figure 8, the four layers of dummy blocks 9 are equipped with adjustment mechanisms 13 in the dummy blocks 1 to 4 layers 9.

[0073] Therefore, compared to Example 2, the adjustment work for the fixing screws 29 and the adjustment mechanism 13 can be reduced. In addition, this modified example can achieve the same effects as Example 2. The adjustment mechanisms 13 for the second and third dummy blocks 9 can be omitted. Furthermore, the adjustment mechanisms 13 for the second and third dummy blocks 9 may be left idle without functioning. In other words, the second and third dummy blocks 9 can be configured without adjusting the frictional force. [Examples]

[0074] Figure 10 is a plan view showing a dummy block according to Embodiment 3. Figure 11 is a cross-sectional view taken along line XI-XI in Figure 10. Figure 12 is a cross-sectional view taken along line XII-XII in Figure 10. Since Embodiment 3 shares the same basic configuration as Embodiment 1, the same or corresponding components are indicated by the same reference numerals, and redundant explanations are omitted.

[0075] As shown in Figure 10, in Embodiment 3, the block body 10 of the dummy block 9 is equipped with movable parts 37 and 39 that engage with the die 3 by friction. The adjustment mechanism 13 is equipped with a drive screw 41 that moves the movable parts 37 and 39. The frictional force of the dummy block 9 against the die 3 is set by the pressure applied by the movable parts 37 and 39 against the die 3.

[0076] The movable parts 37 and 39 in this embodiment are shaped by dividing the block body 10 of the disc or cylindrical dummy block 9 into approximately two sections. The outer circumferential surfaces 37a and 39a of the movable parts 37 and 39 are located approximately on the same circumference. However, the movable parts 37 and 39 only need to be able to contact the inner circumference of the die body 4 and squeeze ring 7 of the die 3, so their shapes can be arbitrarily set to that extent.

[0077] The drive screw 41 has reverse threads at both ends, which are screwed into the movable parts 37 and 39, respectively. The drive screw 41 has an operating part 41a, such as a hexagonal shape, located in the space 49 between the movable parts 37 and 39. This operating part 41 can be operated manually using a tool. The drive screw 41 rotates when the operating part 41 is operated, driving the movable parts 37 and 39 to move closer to and further apart from each other.

[0078] As shown in Figure 11, a grooved guide 43 is provided between the movable parts 37 and 39. The guide 43 is located at two locations on the movable parts 37 and 39. The guide 43 is composed of a recess 45 on the movable part 37 and a protrusion 47 on the movable part 39. The recess 45 and the protrusion 47 fit together in the stacking direction and are slidable in the driving direction of the movable parts 37 and 39.

[0079] In this dummy block 9, the hexagonal portion 41a is rotated using a tool to move the movable parts 37 and 39 relative to each other. This allows the dimensions of the driving direction of the movable parts 37 and 39 of the dummy block 9 to be set, and the frictional force of the dummy block 9 against the squeeze ring 7 of the die 3 to be set.

[0080] Therefore, in Example 3 as well, by setting a frictional force that causes frictional engagement by pressing the movable parts 37 and 39 against the die 3, the same effects as in Example 1 can be achieved. [Examples]

[0081] Figure 13 is a cross-sectional view showing a dummy block according to Embodiment 4. Figure 14 is a plan view of the dummy block in Figure 13. Since Embodiment 4 has the same basic configuration as Embodiment 1, the same or corresponding components are indicated by the same reference numerals, and redundant explanations are omitted.

[0082] As shown in Figures 13 and 14, Embodiment 4 includes an adjustment mechanism 13 which comprises a pressing member 51 that frictionally engages with the die 3 and a drive screw 53 that moves the pressing member 51. The frictional force of the dummy block 9 against the die 3 is set by the pressure applied by the pressing member 51 against the die 3.

[0083] For example, four pressing members 51 are provided. Each pressing member 51 is a rod-shaped member made of resin. The pressing members 51 are slidably arranged in radial slide holes 55 formed in the dummy block 9. A driving inclined surface 51a is formed at the radial inner end of each pressing member 51.

[0084] The slide holes 55 are arranged in four locations circumferentially on the dummy block 9. The tip of the pressing member 51 protrudes from each of these slide holes 55 from the outer circumferential surface of the dummy block 9. This protrusion of the pressing member 51 causes frictional engagement of the pressing member 51 with the inner circumferential surface of the squeeze ring 7. The tip surface of the pressing member 51 is formed into a curved or flat shape according to the inner circumferential surface of the squeeze ring 7.

[0085] The frictional force of the dummy block 9 against the squeeze ring 7 of die 3 is set by the pressure applied by the pressing member 51. The pressing of the pressing member 51 is performed by driving a wedge member 57 that contacts the inclined surface 51a of the pressing member 51 with a drive screw 53. The drive screw 53 is screwed into a screw hole 61 of the dummy block 9.

[0086] An opening 59 is formed in the center of the dummy block 9. The drive screw 53 is accessible through the opening 59.

[0087] Therefore, in this embodiment, when the drive screw 53 is rotated through the opening 59, the wedge member 57 presses against the inclined surface 51a of the pressing member 51, causing the pressing member 51 to move away from it. This movement away from it adjusts the amount that the tip of the pressing member 51 protrudes from the outer surface of the dummy block 9. This amount of protrusion of the pressing member 51 allows the frictional force of the dummy block 9 against the inner circumference of the squeeze ring 7 of the die 3 to be set by the tip of the pressing member 51.

[0088] In this embodiment 4, the frictional force from multiple pressing members 51 can be set by operating a single drive screw 53, making operation easy. The drive screw 53 can be operated by accessing it with a general wrench or screwdriver through the opening 59, making operation extremely easy. In addition, the frictional force can be easily equalized in the circumferential direction.

[0089] Furthermore, the same effects and advantages as in Example 1 can be achieved in this Example 4 as well. [Examples]

[0090] Figure 15 is a cross-sectional view showing the relationship between the dummy block and the squeeze ring according to Example 5. Figure 16 is a plan view showing the dummy block and squeeze ring of Figure 15. Since Example 5 has the same basic configuration as Example 1, the same or corresponding components as in Example 1 are indicated by the same reference numerals, and redundant explanations are omitted.

[0091] As shown in Figures 15 and 16, in Embodiment 5, the adjustment mechanism 13 of the dummy block 9 is equipped with a pressing member 63 and a biasing member 65 instead of the engaging screw 15 of Embodiment 1.

[0092] The adjustment mechanism 13 includes a pressing member 63 that engages with friction and a biasing member 65 that biases the pressing member 63 to protrude. The biasing member 65 is an elastic material such as rubber or a spring.

[0093] The pressing member 63 is a rod-shaped body made of resin and consists of a shaft portion 63a and a head portion 63b. A concave spring receiver 63c is formed on the head portion 63b. A concave spring receiver 17a is formed in the hole 17, with the inner side facing radially. The spring receiver 17a and the spring receiver 63c face each other radially, and a biasing member 65 is interposed between them.

[0094] Therefore, in this embodiment, the biasing member 65 in the hole 17 biases the pressing member 63 radially outward of the dummy block 9. This sets the frictional force for holding the dummy block 9 against the die 3.

[0095] In addition, the same effects and advantages as in Example 1 can be achieved in Example 5.

[0096] [Differentiation] Figure 17 is a cross-sectional view of a modified example, showing the relationship between the dummy block and the squeeze mechanism.

[0097] In the modified example shown in Figure 17, the pressing member 63 and the biasing member 65 are unitized with a frame 67 and attached by fitting them into the outer circumferential surface of the dummy block 9.

[0098] Therefore, the pressing member 63 and the biasing member 65 can be easily replaced by attaching and detaching the frame 67. In addition, the same effects as in Example 5 can be achieved. In the dummy blocks 9 of Examples 1 to 5 described above, it is also possible to use the dummy blocks 9 of Examples 1 and 3 to 5 in appropriate combinations. [Explanation of Symbols]

[0099] 1 punch 3 Dies 4. Die body 7 Squeeze Ring 9 Dummy Blocks 10 Blocks 13 Adjustment mechanism 15 Engaging screws 17 holes 23 Crimping section 25 Iron core pieces 27 Iron core pieces 29 Fixing screws 37, 39 Moving parts 41, 53 Drive screws 51, 63 Pressing member 65. Biasing member

Claims

1. A dummy block is held by friction within the die, which works in cooperation with the punch to punch out a core piece from a steel plate. The punch and die sequentially punch out a plurality of iron core pieces from the steel plate, and the punched iron core pieces are sequentially held in the die and stacked. When stacking the punched core pieces in the die, the punched core pieces are received on the dummy block and the adjacent core pieces of the punched core pieces are fastened together. The frictional force for holding the dummy block inside the die is set by an adjustment mechanism provided in the dummy block. A method for manufacturing laminated iron cores.

2. A method for manufacturing a laminated iron core according to claim 1, The frictional force is set by pressing the engagement screw of the adjustment mechanism against the die. A method for manufacturing laminated iron cores.

3. A method for manufacturing a laminated iron core according to claim 1, The frictional force is set by pressing the pressing member of the adjustment mechanism against the die. The pressing member is moved by a drive screw or biased to protrude by a biasing member. A method for manufacturing laminated iron cores.

4. A method for manufacturing a laminated iron core according to claim 1, The frictional force is set by the pressing of the movable part of the dummy block against the die. The movable part is moved by a drive screw provided in the adjustment mechanism. A method for manufacturing laminated iron cores.

5. A method for manufacturing a laminated iron core according to any one of claims 1 to 4, The dummy blocks are stacked in multiple layers according to the thickness of the laminated iron core, and the dummy blocks at least at both ends in the stacking direction are fastened together. A method for manufacturing laminated iron cores.

6. A method for manufacturing a laminated iron core according to any one of claims 1 to 4, Multiple dummy blocks are stacked according to the thickness of the laminated iron core, The adjacent dummy blocks in the stacked dummy blocks are connected, A method for manufacturing laminated iron cores.

7. A dummy block used when sequentially punching out multiple iron core pieces from a steel plate using a punch and die, and sequentially holding the punched iron core pieces in the die and stacking them, A block body is held within the die by frictional force, receives the punched core piece, and fastens adjacent core pieces to the punched core piece, An adjustment mechanism for setting the frictional force for holding the block body inside the die, A dummy block equipped with this feature.

8. A dummy block according to claim 7, The adjustment mechanism includes an engaging screw, The frictional force is set by pressing the engaging screw against the die. Dummy block.

9. A dummy block according to claim 7, The adjustment mechanism comprises a pressing member and a drive screw for moving the pressing member or a biasing member for biasing the pressing member to protrude. The frictional force is set by pressing the pressing member against the die. Dummy block.

10. A dummy block according to claim 7, The aforementioned block body is equipped with a movable part, The adjustment mechanism includes a drive screw for moving the movable part, The frictional force is set by pressing the movable part against the die. Dummy block.

11. A dummy block according to claim 8, The aforementioned engagement screw is made of resin. Dummy block.

12. A dummy block according to claim 9, The pressing member is made of resin. Dummy block.

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