Laminated iron core and manufacturing method for the laminated iron core

Abstract

To provide a laminated iron core in which laminated iron core pieces are firmly fastened to each other.SOLUTION: A laminated iron core 1 is provided with a plurality of plate-shaped iron core pieces 3 provided with a caulking part 5. The plurality of iron core pieces 3 are laminated in a state in which the caulking part 5 is fitted. A profile of the caulking part 5 viewed from a direction perpendicular to a plate surface of each iron core piece 3 has a first set of opposite sides 11 which is a set of two sides facing each other, and a second set of opposite sides 12 which intersects the first set of opposite sides 11 and is a set of two sides facing each other. It is assumed that a cross-sectional shape cut at a plane perpendicular to the plate surface of each iron core piece 3 and intersecting with the first set of opposite sides 11 is an arc shape, and a cross-sectional shape cut at a plane perpendicular to the plate surface of each iron core piece 3 and intersecting with the second set of opposite sides 12 is a linear shape.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a laminated core including a plurality of plate-shaped core pieces each having a crimped portion, and a method for manufacturing the laminated core. [Background technology]

[0002] For example, laminated cores used in motor rotors and stators are manufactured by stacking a plurality of plate-shaped core pieces each having a crimped portion, with the crimped portions fitted together. Known crimped portions include those with a V-shaped cross section having inclined surfaces on both sides, and those with an inverted trapezoidal cross section (see, for example, Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Utility Model Application Publication No. 57-118640 [Patent Document 2] Japanese Patent Application Laid-Open No. 2001-197693 Summary of the Invention [Problem to be solved by the invention]

[0004] In conventional laminated cores such as those described above, the crimped portions of adjacent core pieces in the stacking direction are fitted together by abutting the inclined surfaces of one core piece (upper layer) and the other core piece (lower layer). However, in crimped portions with a V-shaped or inverted trapezoidal cross section, the inclined surfaces are steep, so the abutting inclined surfaces interfere with each other, creating gaps between the crimped portions. This weakens the fastening strength between the crimped portions, potentially causing the core pieces to separate.

[0005] The present invention has been made in view of the above-mentioned problems, and has an object to provide a laminated core in which laminated core pieces are firmly fastened to each other, and a method for manufacturing such a laminated core. [Means for solving the problem]

[0006] The laminated core according to the present invention, which solves the above problems, has the following characteristic configuration: A laminated core including a plurality of plate-shaped core pieces each having a crimped portion, The plurality of core pieces are stacked with the crimped portions fitted together, The crimped portion has an outline, when viewed from a direction perpendicular to the plate surface of the core piece, that has a first set of opposing sides that are a set of two opposing sides and a second set of opposing sides that intersects with the first set of opposing sides and is also a set of two opposing sides, and the cross-sectional shape when cut at a plane that is perpendicular to the plate surface of the core piece and intersects with the first set of opposing sides is arc-shaped, and the cross-sectional shape when cut at a plane that is perpendicular to the plate surface of the core piece and intersects with the second set of opposing sides is linear.

[0007] In the laminated core of this configuration, the crimped portion has an arc-shaped cross section taken along a plane perpendicular to the plate surface of the core piece and intersecting with the first pair of opposite sides, and a linear cross section taken along a plane perpendicular to the plate surface of the core piece and intersecting with the second pair of opposite sides. With crimped portions of this shape, when the crimped portions are fitted together, they are crimped together without interfering with each other. Therefore, the laminated core pieces can be firmly fastened together.

[0008] In the laminated core according to the present invention, It is preferable that the peel strength of the iron core pieces adjacent in the stacking direction is 200 N / mm or more.

[0009] With a laminated core of this configuration, the peel strength of adjacent core pieces in the lamination direction is 200 N / mm or more. Therefore, for example, when this laminated core is applied to an electric motor, it is possible to prevent increases in noise and vibration, worsening cogging, and decreases in output.

[0010] Next, the characteristic configuration of the manufacturing method of the laminated core according to the present invention for solving the above problems is as follows: a stacking step of stacking a plurality of core pieces each having an engaging portion thereon so that the engaging portions are engaged with each other; a crimping portion forming step of pressing a punch against the engaging portion of the core piece in the uppermost layer to form a crimped portion; It encompasses The engaging portion has a contour, when viewed from a direction perpendicular to the plate surface of the core piece, that has a first set of opposing sides that are a set of two opposing sides and a second set of opposing sides that intersects with the first set of opposing sides and is also a set of two opposing sides, and the cross-sectional shape when cut along a plane that is perpendicular to the plate surface of the core piece and intersects with the first set of opposing sides is V-shaped, and the cross-sectional shape when cut along a plane that is perpendicular to the plate surface of the core piece and intersects with the second set of opposing sides is linear, The crimped portion has an arc-shaped cross-sectional shape when cut along a plane perpendicular to the plate surface of the core piece and intersecting with the first set of opposite sides, and a linear cross-sectional shape when cut along a plane perpendicular to the plate surface of the core piece and intersecting with the second set of opposite sides.

[0011] According to the manufacturing method of a laminated core having this configuration, the engaging portions of the core pieces have a V-shaped cross section taken along a plane perpendicular to the plate surfaces of the core pieces and intersecting with the first set of opposite sides, and a linear cross section taken along a plane perpendicular to the plate surfaces of the core pieces and intersecting with the second set of opposite sides. With engaging portions of this shape, the engaging portions of multiple core pieces can be easily engaged with each other, allowing the core pieces to be smoothly stacked in the stacking process. Then, by performing the crimping portion forming process, crimping portions are formed that have an arc-shaped cross section taken along a plane perpendicular to the plate surfaces of the core pieces and intersecting with the first set of opposite sides, and a linear cross section taken along a plane perpendicular to the plate surfaces of the core pieces and intersecting with the second set of opposite sides. With crimping portions of this shape, when the crimping portions are fitted together, the constituent surfaces of the crimping portions are crimped together without interfering with each other. Therefore, a laminated core can be obtained in which the stacked core pieces are firmly fastened together.

[0012] In the method for manufacturing a laminated core according to the present invention, It is preferable that the protruding height of the punch is 0.3 mm or more.

[0013] According to the manufacturing method of the laminated core of this configuration, the protruding height of the punch is 0.3 mm or more, so that by pressing the punch against the engaging portion of the core piece of the top layer, the engaging portions of each of the stacked core pieces can be deformed to reliably form the crimped portion. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a diagram showing a laminated core according to one embodiment of the present invention. [Figure 2] FIG. 2 is a perspective view of a punch used in manufacturing a laminated core. [Figure 3] FIG. 3 is a diagram showing a core piece provided with an engagement portion. [Figure 4] FIG. 4 is an explanatory diagram of a method for manufacturing a laminated core according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0015] The present invention will be described below with reference to the drawings. In the following embodiments, a laminated core constituting a rotor or stator will be described as an example. However, the present invention is not intended to be limited to the embodiments described below or the configurations shown in the drawings. In addition, although Figures 1, 3, and 4 show a state in which multiple iron core pieces 3 (described later) are stacked, the thickness relationships between the layers (iron core pieces) have been appropriately exaggerated or simplified, and do not strictly reflect the actual relationship (scale) in the thickness of each layer.

[0016] <Schematic structure of laminated core> FIG. 1 is a diagram showing a laminated core 1 according to one embodiment of the present invention. FIG. 1(a) is a plan view of a main portion of the laminated core 1, FIG. 1(b) is a cross-sectional view taken along the line AA in FIG. 1(a), and FIG. 1(c) is a cross-sectional view taken along the line BB in FIG. 1(a). The laminated core 1 shown in FIGS. 1(a) to 1(c) includes a plurality of disk-shaped core pieces 3 that are stamped and formed by pressing electromagnetic steel sheets. In the laminated core 1, each of the plurality of core pieces 3 is provided with a required crimped portion 5 (excluding the core piece 3 in the bottom layer). In the laminated core 1, the crimped portions 5 of the plurality of core pieces 3 adjacent in the stacking direction are fitted together.

[0017] <Crimped part> 1(a), the outline of the crimped portion 5 is rectangular in this example when viewed from a direction perpendicular to the plate surface of the core piece 3. That is, the outline has a first set of opposite sides 11, which are a set of two sides that are parallel to each other and face each other, and a second set of opposite sides 12, which intersects with the first set of opposite sides 11 (orthogonal in this example) and is also a set of two sides that are parallel to each other and face each other.

[0018] 1(b) and 1(c), the crimped portion 5 has a recess 5a formed on one plate surface side of the core piece 3 and a protrusion 5b formed on the other plate surface side of the core piece 3 so as to be one with the recess 5a. In the core pieces 3 adjacent in the stacking direction, the protrusion 5b in the crimped portion 5 of the core piece 3 in the upper layer is fitted into the recess 5a in the crimped portion 5 of the core piece 3 in the lower layer. Note that the core piece 3 in the bottom layer does not have a crimped portion 5, but has a through hole 7 formed by full punching, and the protrusion 5b in the crimped portion 5 of the core piece 3 in the upper layer is fitted into this through hole 7.

[0019] In this embodiment, the peel strength of adjacent core pieces 3 in the lamination direction is set to 200 N / mm or more. By setting the peel strength to 200 N / mm or more, when the laminated core 1 is applied to an electric motor, for example, it is possible to prevent increases in noise and vibration, worsening cogging, reductions in output, and the like.

[0020] As shown in FIG. 1(b), the crimped portion 5 has an arc-shaped cross section (cross section as viewed in a first direction) cut along a plane that is perpendicular to the plate surface of the core piece 3 and intersects (orthogonal to) the first set of opposite sides 11 (see FIG. 1(a)). Also, as shown in FIG. 1(c), the crimped portion 5 has a linear cross section (cross section as viewed in a second direction) cut along a plane that is perpendicular to the plate surface of the core piece 3 and intersects (orthogonal to) the second set of opposite sides 12 (see FIG. 1(a)). Note that in FIG. 1(c), the cross section of the crimped portion 5 appears to be rectangular rather than linear. This is because the thickness of the core pieces 3 has been exaggerated in order to make it easier to understand the laminated state of the core pieces 3. The thickness of the actual core pieces 3 is extremely small compared to the overall thickness of the laminated core, and therefore the cross section of the crimped portion 5 in the actual core piece 3 is linear (the same applies to FIG. 3(c)).

[0021] With the crimping portions 5 having such a shape, when the crimping portions 5 are fitted together, the surface of the recessed portion 5a of one crimping portion 5 and the surface of the protruding portion 5b of the other crimping portion 5 are crimped together without interfering with each other. Therefore, the stacked core pieces 3 can be firmly fastened together.

[0022] <punch> 2 is a perspective view of punches 21 and 22 used when manufacturing the laminated core 1. Fig. 2(a) shows a first punch 21 used when forming an engaging portion 50 (described later) on the core piece 3, and Fig. 2(b) shows a second punch 22 that presses the engaging portion 50 provided on the core piece 3.

[0023] As shown in Figure 2(a), the first punch 21 is composed of a rectangular prism-shaped shank portion 31 extending vertically, and a tip functional portion 32 provided integrally below the shank portion 31. The tip functional portion 32 of the first punch 21 has a pair of inclined surfaces 33 that are inclined so that the distance between them decreases as they extend downward.

[0024] As shown in FIG. 2(b), like the first punch 21, the second punch 22 is also composed of a rectangular prism-shaped shank portion 41 extending vertically and a tip functional portion 42 provided integrally on the lower side (pressing direction side) of the shank portion 41. The tip functional portion 42 of the second punch 22 has an arc-shaped surface 43 that protrudes downward. The tip functional portion 42 is a portion that essentially functions to press the engaging portion 50 and form the crimped portion 5. Hereinafter, the protruding length of the tip functional portion 42 from the shank portion 41 in the pressing direction (the length of the arrow portion marked with the symbol "h" in FIG. 2(b)) is referred to as the protruding height of the punch.

[0025] <Engagement part> FIG. 3 is a diagram showing an iron core piece 3 provided with an engaging portion 50. FIG. 3(a) is a plan view of a main portion of the iron core piece 3 provided with the engaging portion 50, FIG. 3(b) is a cross-sectional view taken along the line CC in FIG. 3(a), and FIG. 3(c) is a cross-sectional view taken along the line DD in FIG. 3(a). When performing the stacking process described below, an engaging portion 50 as shown in FIGS. 3(a) to 3(c) is formed in advance on each of the multiple iron core pieces 3 to be stacked. As shown in FIG. 3(b), the engaging portion 50 is formed by abutting and pressing a pair of inclined surfaces 33 of the tip functional portion 32 of the first punch 21 against a portion of the plate surface of the iron core piece 3 where a crimping portion is to be formed.

[0026] 3(a), the outline of the engaging portion 50 seen from a direction perpendicular to the plate surface of the core piece 3 is the same as the outline of the crimped portion 5. That is, the outline of the engaging portion 50 has a first set of opposite sides 61, which is a set of two sides that are parallel to each other and face each other, and a second set of opposite sides 62 that intersects with the first set of opposite sides 61 (orthogonal in this example) and is also a set of two sides that are parallel to each other and face each other.

[0027] As shown in Figures 3(b) and (c), the engagement portion 50 has a recess 50a formed on one plate surface side of the core piece 3 and a protrusion 50b formed on the other plate surface side of the core piece 3 so as to be one with the recess 50a.

[0028] As shown in FIG. 3(b), the engaging portion 50 has a V-shaped cross section (cross section as viewed in a first direction) cut along a plane that is perpendicular to the plate surface of the core piece 3 and intersects (orthogonal to) the first set of opposite sides 61 (see FIG. 3(a)). Also, as shown in FIG. 3(c), the engaging portion 50 has a linear cross section (cross section as viewed in a second direction) cut along a plane that is perpendicular to the plate surface of the core piece 3 and intersects (orthogonal to) the second set of opposite sides 62. With an engaging portion 50 having such a shape, when the core pieces 3 are stacked, the convex portion 50b of the engaging portion 50 of the core piece 3 of an upper layer can easily fit into the concave portion 50a of the engaging portion 50 of the core piece 3 of a lower layer, and the engaging portions 50 of multiple core pieces 3 can be easily engaged with each other, allowing the core pieces 3 to be stacked smoothly in the stacking process described below.

[0029] <Laminated core manufacturing method> 4A to 4C are explanatory diagrams of a manufacturing method of a laminated core 1 according to one embodiment of the present invention. In order to facilitate understanding of the drawings, a lower mold supporting the core pieces 3 and an upper mold supporting the second punch 22 are not shown in FIGS. 4A to 4C.

[0030] <Lamination process> 4(a), the core piece 3 on which the engaging portion 50 is formed is placed on top of the core piece 3 of the lowest layer so that the protrusion 50b of the engaging portion 50 of the core piece 3 of the upper layer engages with the through hole 7 of the core piece 3 of the lowest layer, and then the protrusion 50b of the engaging portion 50 of the core piece 3 of the upper layer is fitted into the recess 50a of the engaging portion 50 of the core piece 3 of the lower layer to engage the engaging portions 50, and similar steps are repeated to place a predetermined number of core pieces 3 on top of each other. Here, an example is shown in which five core pieces 3 are placed on top of the core piece 3 of the lowest layer, but this is not limited to this and any appropriate number of core pieces can be placed on top of each other.

[0031] <Crimping process> As shown in FIG. 4(b), the arc-shaped surface 43 of the tip functional portion 42 of the second punch 22 is brought into contact with and pressed against the recess 50a of the engaging portion 50 of the core piece 3 of the uppermost layer. As a result, the engaging portion 50 is deformed from a V-shaped cross section as shown in FIG. 4(b) to an arc-shaped cross section as shown in FIG. 4(c) in accordance with the shape of the arc-shaped surface 43 of the tip functional portion 42, forming the crimped portion 5. As a result, the surface of the convex portion 5b of the crimped portion 5 of the core piece 3 of the upper layer and the surface of the recess 5a of the crimped portion 5 of the core piece 3 of the lower layer are crimped together without interfering with each other. Therefore, a laminated core 1 can be manufactured in which the stacked core pieces 3 are firmly fastened together. [Example]

[0032] Hereinafter, examples of the laminated core and the manufacturing method of the laminated core according to the present invention will be described, but the present invention is not limited to these examples.

[0033] Example 1 The peel strength of the laminated core of the present invention, which is constructed by laminating the core pieces shown in Table 1 below, was measured.

[0034] [Table 1]

[0035] <Peel strength measurement> A locking pin was fixed to the top core piece of the laminated core at a radial distance of 50 mm from the center of the core piece, a hook on a push-pull gauge was hooked onto the locking pin, and the push-pull gauge was slowly pulled in a direction perpendicular to the lower core piece, and the maximum force (N) applied to the push-pull gauge until the top core piece peeled off from the lower core piece was measured. Since the maximum width of contact between the top core piece and the lower core piece corresponds to the diameter of the core piece, the value obtained by dividing the measured maximum force (N) by the diameter of the core piece was calculated as the peel strength (N / mm).

[0036] (Comparative Example 1) The peel strength of a laminated core constituted by laminating core pieces similar to those in Table 1 except that the cross-sectional shape as viewed in the first direction in Table 1 was V-shaped was measured in the same manner as above.

[0037] (Comparative Example 2) The peel strength of a laminated core constituted by laminating core pieces similar to those in Table 1 except that the cross-sectional shape as viewed in the first direction in Table 1 was an inverted trapezoidal shape was measured in the same manner as above.

[0038] Table 2 shows the results of the peel strength measurements. [Table 2]

[0039] As shown in Table 2, the peel strength of the laminated core of the present invention is approximately 1.5 times that of a conventional laminated core with a V-shaped crimped portion and approximately twice that of a conventional laminated core with an inverted trapezoidal crimped portion. Therefore, in the laminated core of the present invention, the laminated core pieces are fastened together more firmly than in the past.

[0040] A plurality of core pieces (five in this example) shown in Table 3 below were stacked, and the crimped portion forming process was carried out by changing the protruding height of the second punch. Here, the number of stacked core pieces is the number of core pieces stacked on top of the core piece in the bottom layer with a through hole, and the core piece in the bottom layer with a through hole is not included in the count of the number of stacked pieces.

[0041] [Table 3]

[0042] <Evaluation of the formation state of the crimped part> The state of crimping was evaluated by rating it as "Good" if crimping was formed on all of the laminated core pieces, and rating it as "Poor" if no crimping was formed on even one of the laminated core pieces. The results are shown in Table 4.

[0043] [Table 4]

[0044] As shown in Table 4, when the protruding height h of the punch (see Figure 2(b)) was 0.3 mm or more, by pressing the punch against the engaging portion of the core piece in the top layer, the engaging portions of each of the stacked core pieces were deformed to form a crimped portion. [Industrial Applicability]

[0045] The laminated core of the present invention is suitable for use as a core for rotating electrical machines such as motors and generators, and for electrical equipment such as transformers. [Explanation of symbols]

[0046] 1 Laminated core 3 Core pieces 5 Crimping part 11 Opposite sides of the first pair 12 Second pair of opposite sides 21 First Punch 22 Second Punch 50 engagement portion 61 First pair of opposite sides 62 Second pair of opposite sides

Claims

1. A laminated core including a plurality of plate-shaped core pieces each having a crimped portion, The plurality of core pieces are stacked with the crimped portions fitted together, A laminated iron core in which the outline of the crimped portion, when viewed from a direction perpendicular to the plate surface of the core piece, has a first set of opposing sides that are a set of two opposing sides and a second set of opposing sides that intersects with the first set of opposing sides and is also a set of two opposing sides, and the cross-sectional shape when cut at a plane that is perpendicular to the plate surface of the core piece and intersects with the first set of opposing sides is arc-shaped, and the cross-sectional shape when cut at a plane that is perpendicular to the plate surface of the core piece and intersects with the second set of opposing sides is linear.

2. 2. The laminated core according to claim 1, wherein the peel strength of the core pieces adjacent in the lamination direction is 200 N / mm or more.

3. a stacking step of stacking a plurality of core pieces each having an engaging portion thereon so that the engaging portions are engaged with each other; a crimping portion forming step of pressing a punch against the engaging portion of the core piece in the uppermost layer to form a crimped portion; It encompasses The engaging portion has a contour, as viewed from a direction perpendicular to the plate surface of the core piece, which has a first set of opposite sides that are a set of two sides facing each other and a second set of opposite sides that intersects with the first set of opposite sides and is also a set of two sides facing each other, and the cross-sectional shape when cut along a plane that is perpendicular to the plate surface of the core piece and intersects with the first set of opposite sides is V-shaped, and the cross-sectional shape when cut along a plane that is perpendicular to the plate surface of the core piece and intersects with the second set of opposite sides is linear, A method for manufacturing a laminated core, wherein the crimped portion has an arc-shaped cross-sectional shape when cut along a plane perpendicular to the plate surface of the core piece and intersecting with the first set of opposite sides, and has a linear cross-sectional shape when cut along a plane perpendicular to the plate surface of the core piece and intersecting with the second set of opposite sides.

4. 4. The method for manufacturing a laminated core according to claim 3, wherein the punch has a protruding height of 0.3 mm or more.

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