JP6307285B2 - Punching method of iron core pieces - Google Patents

Description

The present invention relates to a method of punching out an iron core piece forming a laminated iron core constituting a rotor, a stator or a transformer of a motor, for example.

In recent years, in order to improve motor performance, iron core pieces used for forming a laminated iron core constituting a rotor or a stator tend to be thinned. As a result, the number of punched iron cores has increased significantly. As a result, the time required to punch the core pieces as many as necessary to form the laminated core from the work plate has been increased, improving the productivity of the laminated core. It is difficult to plan.
Therefore, for example, it has been proposed to punch the core pieces in a state where two plates to be processed are stacked, to shorten the time required for punching the necessary number of core pieces, and to improve the productivity of the laminated core. (For example, refer to Patent Document 1).

JP 55-156623 A

In general, as shown in FIG. 9A, a plate-like work plate 81 is placed on a die 80, and a punch 82 is pushed into the fixed blade of the die 80 through the work plate 81, so that the work plate is processed. When forming a hole in 81, the processed surface of the hole formed in the processed plate 81 is changed from the surface of the processed plate 81 (the surface into which the punch 82 is pushed) to the back surface (die) as shown in FIG. Slidable portion formed by pressing the punch 82 into the processed plate 81 toward the surface 80), and formed by locally extending the processed plate 81 into the punch 82 and the die 80. It is constituted by a shearing part, a break part formed by breaking the work plate 81 drawn into the punch 82 and the die 80, and a burr generated on the back side of the work plate 81.

However, as shown in FIG. 10 (A), the two processed plates 83 and 84 are placed on the die 80, and the punch 82 is pushed into the die 80 via the processed plates 83 and 84. When holes are formed in the processed plates 83 and 84, as shown in FIG. 10B, the processed surface of the holes formed in the processed plate 83 on the punch 82 side is sag sequentially from the surface side of the processed plate 83. The processing surface of the hole formed in the work plate 84 on the die 80 side is different from the case of the work plate 83 on the punch 82 side. Many burrs are formed, and large burrs are formed on the back side of the processed plate 84. For this reason, when the laminated cores are formed by laminating the core pieces punched and formed from the processed plates 83 and 84 in a state where the two sheets are stacked, not only the contour accuracy of the machined surface is lowered due to the influence of the fracture portion, but also the iron cores. Since the strain remaining in the piece increases, the iron loss of the laminated core increases, and the motor characteristics may be deteriorated. In addition, since the ratio of the fractured portion in the processed surface of the iron core piece is large, there is a problem that the wear of the punch becomes severe.

The present invention has been made in view of such circumstances, and when punching and forming core pieces in a state of being stacked from a plurality of processed plates, it is possible to form shear portions on the processing surfaces of all the core pieces. An object of the present invention is to provide a method for punching a core piece.

The method for punching an iron core piece according to the present invention that meets the above-described object uses a die that is fixedly arranged and a punch that is paired with the die, and punches and forms the iron core piece from a plurality of stacked work plates. In the punching method of iron core pieces,
The angle of the edge of the edge of the edge where the punch first comes into contact with the work plate is an acute angle, and the inclined edge intersects with the edge of the fixed edge of the die at all or a part of the movable edge of the punch. And the punch has a bottomed bottom that is recessed in the axial direction of the punch with respect to the tip of the cutting edge,
The level difference between the tip of the blade edge and the bottom is set to at least nt when punching n sheets of the work plate having a thickness t,
The inclined blade sequentially applied to the target plate of n ply, to form the shearing section on the respective target plate performs punching of the core pieces, the bottom the die side of the cutting edge of the punch To penetrate.

By causing the inclined blades to sequentially act on the plurality of workpiece plates, small cuts penetrating the stacked workpiece plates can be sequentially formed along the locus of the action site between the inclined blades and the fixed blade. Then, when the action of the inclined blade and the work plate is completed, the formation of one pattern (contour surface) constituting the iron core piece is completed, and when the formation of all the patterns is completed, the work to be overlapped is completed. The punching of the plate is completed, and the core pieces can be punched and formed from the stacked workpiece plates in a stacked state.
Here, the machined surfaces of the small cuts that pass through the stacked workpiece plates are a set of partial machining surfaces formed on each workpiece plate, and the inclined blades are the workpiece plates. Sag formed by being pushed in, sheared part formed by locally stretching the work plate as the inclined blade enters, and fracture formed by locally breaking the stretched work sheet And a burr generated on the back surface side of the workpiece plate (the workpiece plate or the surface contacting the die disposed on the lower side). For this reason, the ratio of the shearing part which exists in the processing surface becomes high.
Note that the edge angle means the minimum value of the angle formed when two contour lines forming the cross-section of the blade edge intersect at the edge of the blade edge. For example, one edge line intersected at the edge of the blade edge is the punch line. It is an angle formed by two contour lines when the punch is viewed in cross-section so that it is parallel to the punching direction (one contour line is linear). Therefore, when the other contour line is the blade edge of the inclined blade and the inclined blade is linear, the blade edge angle is the intersection angle of the two straight lines, and when the other contour line is on the curve, This is the angle of intersection between the tangent line at the tip of the blade edge and one straight outline.

In the punching method of the iron core piece according to the present invention, the entire cutting edge of the punch may be the inclined blade, and the punch may have two opposing cutting edges that contact the workpiece plate.

In the punching method of the iron core piece according to the present invention, the cutting edge of the punch may have a linear blade that simultaneously contacts the inclined blade and the work plate at the same time.
Here, two said linear blades can be provided facing each other.

In the punching method of the iron core piece according to the present invention, when performing the punching process of the two processed plates, the thickness of each processed plate is set to 0.1 mm or more and 0.5 mm or less, and the cutting edge angle is set. Is preferably formed at 30 degrees or more and 89 degrees or less.
Here, if the thickness of the processed plate is less than 0.1 mm, the rigidity of the processed plate is lowered, and it becomes difficult to handle the processed plate. Further, if the thickness of the workpiece plate exceeds 0.5 mm, it is necessary to increase the punch stroke of the punching die device in order to penetrate the blade edge having an acute edge angle through the two stacked workpiece plates. Therefore, it is not preferable.

In the punching method of the core piece according to the present invention, the clearance set between the fixed blade of the die and the movable blade of the punch used when punching and forming the core piece from one piece of the work plate is the work piece. The clearance between the fixed blade of the die and the movable blade of the punch is 7 to 11% of the thickness of the plate, and the punching process is performed on the two stacked plates. It is preferable to set it in the range of 3.5 to 5.5%.
Here, when the clearance set when punching and forming the iron core piece from one work plate is less than 7% of the thickness of the work plate, the work plate arranged on the die side has a movable punch blade. The cracks generated on the side and the cracks generated on the fixed blade side of the die do not match (is connected), which is not preferable. On the other hand, if the clearance exceeds 11% of the thickness of the processed plate, the sag portion and the burr become larger and the processed plate is warped, which is not preferable. If the clearance set when punching and forming the iron core piece from two stacked work plates is less than 3.5% of the thickness of the work plate, a whisker-like burr will appear on the work plate placed on the die side. If it is formed and exceeds 5.5% of the thickness of the plate to be processed, the burr becomes large, which is not preferable.

In the punching method of the iron core piece according to the present invention, the partial machining surface formed on each of the stacked work plates has a sag portion formed by the inclined blade being pushed into the work plate, with the approach of the inclined blade. A sheared portion formed by locally stretching the work plate, a fracture portion formed by locally breaking the stretched work plate, and a back surface side of the work plate (a work piece disposed on the lower side) Since it is constituted by burrs generated on the processed plate or the surface abutting on the die, the ratio of the shearing portion existing on the processed surface formed on the stacked processed plates is increased. Here, since the sheared portion has a smooth surface and a small amount of residual strain, the contour accuracy of the laminated core formed by stacking the core pieces is improved, and the positioning accuracy of the member (for example, shaft) attached to the laminated core is improved. As a result of the formation of a laminated core with little residual strain, the iron loss of the laminated core can be reduced. Furthermore, since the ratio of the broken portion existing on the cut surface is reduced, the wear of the punch is reduced and the punch life is extended.

In the punching method of the iron core piece according to the present invention, when punching two stacked workpiece plates, the thickness of each workpiece plate is set to 0.1 mm or more and 0.5 mm or less, and the edge angle is set to 30 degrees. In the case of forming at 89 ° or less, it is possible to prevent an excessive increase in the punch stroke required for punching the core piece.

In the punching method of the iron core piece according to the present invention, the clearance set between the fixed blade of the die and the movable blade of the punch used when punching and forming the iron core piece from one work plate is the thickness of the work plate. 7 to 11% of the thickness, and the clearance between the fixed blade of the die and the movable blade of the punch when punching two stacked workpiece plates is set to 3.5 to 5 of the thickness of the workpiece plate. When set to the range of 5%, the protruding length (vertical burr height) along the punching direction of the burr formed on the core piece produced from the work plate arranged on the die side can be reduced.

(A) is explanatory drawing at the time of performing the punching process of the two strips laminated by the punching method of the core piece according to the first embodiment of the present invention, and (B) is a punching process of round holes in the strips. FIG. (A) is a perspective view of the cutting edge side of a punch used in the punching method of the iron core piece, (B) and (C) are side views as viewed from the U and V directions of (A), and (D) is (A). It is the bottom view seen from the W direction. It is sectional drawing which shows the condition at the time of the punching process of the strip | belt board material which piled up two sheets using the punch. It is explanatory drawing of the internal peripheral surface of a round hole. (A) is explanatory drawing at the time of performing the punching process of the strip | belt board material piled up by the punching method of the core piece which concerns on the 2nd Embodiment of this invention, (B) has punched the square hole in the strip board | plate material. FIG. (A) is a perspective view of a cutting edge side of a punch used in the punching method of the iron core piece, (B) and (C) are side views as viewed from the X and Y directions of (A), and (D) is (A). It is the bottom view seen from the Z direction. It is explanatory drawing of the internal peripheral surface of a square hole. It is a graph which shows the influence of the clearance gap between the fixed blade of a die | dye, and the movable blade of a punch on the vertical burr height of the burr | flash formed in the strip | belt board material of the die | dye side of the square hole punched in the Example. (A) is explanatory drawing at the time of punching a hole in a to-be-processed board using die | dye and a punch, (B) is a sectional side view which shows the state of the processed surface of a hole. (A) is explanatory drawing at the time of punching a hole in a to-be-processed board with the 2 sheet | seat superposition method which concerns on a prior art example, (B) is a sectional side view which shows the state of the processed surface of a hole.

Next, embodiments of the present invention will be described with reference to the accompanying drawings for understanding of the present invention.
As shown in FIG. 1 (A), a punching method of an iron core piece according to the first embodiment of the present invention includes a die 10 that is fixedly arranged side by side in a lower die (not shown) of a punching die device, Using a punch 11 that is provided side by side with an upper die (not shown) of the punching die device in a pair with the die 10 and moves up and down together with the upper die, for example, two sheets of strip material (an example of a plate to be processed) 12 and 13 (in FIG. 1A, the strip plate material 13 is disposed on the die 10 side and the strip plate material 12 is disposed on the punch 11 side), and an iron core piece (not shown) is punched and formed. Here, thickness t (refer FIG. 3) of the strip | belt board materials 12 and 13 is 0.1 mm or more and 0.5 mm or less, respectively. In FIG. 1A, in a die and a punch arranged side by side in a lower mold and an upper mold, as shown in FIG. Only one set of dies 10 and punches 11 is shown. Details will be described below.

As shown in FIGS. 2 (A) to 2 (D), the punch 11 for punching and forming the round holes 14 in the two stacked strips 12 and 13 respectively has two cutting edges 15 and 16 that contact the strips 12 and 13. Are opposed to both sides of the axial center of the punch 11. The cutting edges 15 and 16 are, as shown in FIG. 2 (D), cutting edge tips 17 and 18 that are opposed to each other on the outer periphery of the punch 11 with the center of the punch 11 in between when viewed from the bottom. An area along the perpendicular bisector connecting the cutting edge tips 17 and 18 is recessed in the axial direction of the punch 11 with respect to the cutting edge tips 17 and 18, and the cutting edge tips 17 and 18 and the bottom part. Inclined portions 20 and 21 for connecting 19.

Therefore, as shown in FIG. 2 (C), the blade edge angles θ of the blade edge tips 17 and 18 that first contact the strips 12 and 13 are acute angles, for example, 30 degrees to 89 degrees, and the punch 11 All of the movable blades, that is, all of the blade edges 15 and 16 intersect with the blade edge of the fixed blade of the die 10 (clearance with respect to the blade edge of the fixed blade of the die 10 (3 of the thickness t of the strips 12 and 13). 0.5 to 5.5%), and the inclined blades 24 and 25 pass through. For this reason, the inclined blades 24 and 25 sequentially act on the two overlapping strips 12 and 13 to perform punching of one pattern constituting the core piece. In addition, since the inclined blades 24 and 25 exist along the intersection region between the outer periphery of the punch 11 and the surfaces of the inclined portions 20 and 21, the step S between the blade tips 17 and 18 and the bottom portion 19 is different from the punch 11. Rtan (90−θ), where R is the radius of. Here, in order to punch and form the iron core piece, the bottom 19 of the cutting edges 15 and 16 needs to penetrate to the die 10 side, and the total thickness of the strips 12 and 13 in which at least two steps S are stacked. It is necessary to set it to 2t (in the case of stacking n strips of thickness t, n).
The angle 90-θ (the angle α in FIG. 3) is an intersection angle between the surfaces of the inclined portions 20 and 21 (inclined blades 24 and 25) and a plane (straight line) orthogonal to the punching direction of the punch 11. Also called a horn.

As shown in FIG. 3, when the two strips 12 and 13 are placed on the die 10 and the punch 11 is lowered from above, the blade tip angle θ is an acute angle. , 18 can first abut against and press the strip 12 (the pressing load applied to the punch 11 can be concentrated on the blade tips 17, 18), and the material existing on the tip side of the blade tips 17, 18 Plastic deformation (shear deformation) is promoted and the blade tips 17 and 18 easily bite into the strip 12 (a shear portion is formed). At this time, as shown in FIG. 4, a minute sag portion 54 is formed in the surface layer side region of the band plate material 12.

When the punch 11 continues to descend, the shear deformation of the material existing on the tip side of the blade tips 17 and 18 continuously occurs, so that the material constituting the strip plate material 12 is gradually work-hardened to form the strip plate material 12. The acting shear force increases, and the tensile strain of the material existing on the front side of the blade tips 17 and 18 also increases. For this reason, when the cutting edge tips 17 and 18 bite into the band plate material 12 and the shearing portion 55 is formed to some extent, the tensile strain reaches the tensile strain amount when the tensile breakage occurs in the band plate material 12, A fracture portion 56 is formed in a rear surface side region of the plate material 12 (region on the side in contact with the strip plate material 13). Then, the burrs 57 are formed on the back side of the band plate material 12 by the cutting edge tips 17 and 18 penetrating the band plate material 12. Then, the blade tips 17 and 18 penetrate the strip plate material 12 and simultaneously come into contact with and press the strip plate material 13. In addition, since the effect | action which the blade edge | tip tips 17 and 18 exert on the strip plate material 13 is the same as that of the strip plate material 12, description is abbreviate | omitted. When the blade tips 17 and 18 penetrate the strip material 13, the first small notches penetrating the strip materials 12 and 13 are formed.

On the other hand, when the cutting edge tips 17 and 18 bite into the band plate material 12, the portions on the inclined blades 24 and 25 above the cutting edge tips 17 and 18 abut against and press the band plate material 12. And the site | part on the inclined blades 24 and 25 above the blade-tip tips 17 and 18 penetrates the strip | belt board materials 12 and 13 similarly to the blade-tip tips 17 and 18. FIG. As a result, the first small notches penetrating the two stacked strips 12 and 13 follow the locus of the portions on the inclined blades 24 and 25 that contact and press the strip 12 (along the outer peripheral surface of the punch 11). Grow). In this way, since the action portions where the inclined blades 24 and 25 of the punch 11 sequentially act on the strips 12 and 13 move on the inclined blades 24 and 25, the cutting of the inclined blade 24 and the cutting of the inclined blade 25 are performed. When the two are joined (continuous), as shown in FIG. 1 (B), the circular holes 14 are formed in the two stacked strips 12 and 13, respectively.

Here, since the round holes 14 respectively processed in the two-layered strips 12 and 13 are formed by the growth of the first small notches that pass through the two-layered strips 12 and 13, The inner contour surfaces of the round holes 14 formed in the plate members 12 and 13 are respectively formed as the sag portions 54 and the inclined blades 24 and 25 are formed by the inclined blades 24 and 25 being pushed into the band plate members 12 and 13. The shearing part 55 formed by locally stretching the strips 12 and 13, the breaking part 56 formed by locally breaking the stretched strips 12 and 13, and the back side of the strips 12 and 13 Therefore, the ratio of the shearing portion 55 existing on the total inner contour surface of the total round hole formed in the two-layered strips 12 and 13 is 2 by the conventional method. Of the total round holes formed in the strip material Higher compared to the proportion of the shear portion present on the inner contour surface. For this reason, the total inner contour surface of the total round hole formed in the two-layered strips 12 and 13 is smooth and has high contour accuracy, and the amount of strain remaining in the surface layer region is small. Furthermore, since the ratio of the broken portion existing on the cut surface is low, the wear of the punch 11 is reduced and the punch life is extended.

As shown in FIG. 5 (A), the punching method of the iron core piece according to the second embodiment of the present invention includes a die 26 fixedly arranged side by side in a lower die (not shown) of the punching die device, For example, two strips 12 and 13 (FIG. 5 (FIG. 5 (FIG. 5A)) are formed by using a punch 27 that is provided side by side with an upper die (not shown) of the punching die device and moves up and down together with the upper die. In A), an iron core piece (not shown) is punched and formed from the strip plate 13 on the die 26 side and the strip plate 12 on the punch 27 side. In FIG. 5A, among the dies and punches arranged side by side in the lower mold and the upper mold, as shown in FIG. Only a pair of dies 26 and punches 27 are shown. Details will be described below.

As shown in FIGS. 6 (A) to 6 (D), the punch 27 for punching and forming the square holes 28 in the two stacked strips 12 and 13 has a square cross section. As shown in FIG. 6D, the punch 27 has two pairs of sides when viewed from the bottom, and a line segment connecting the midpoints 29 and 30 of one side of the pair. A bottom portion 31 is formed with a region along which the bottom portion 31 is recessed in the axial direction of the punch 27, and inclined portions 34 and 35 that connect the other pair of sides 32 and 33 and the bottom portion 31 are provided. For this reason, the punch 27 has two edges 32 and 33 provided opposite to each other as the tip of the cutting edge, and the cutting edge becomes a straight edge (an example of a linear blade) that simultaneously contacts the strips 12 and 13 at the same time. 38 and 38a are provided. Further, the punch 27 has two wall surfaces 36 and 37 that are connected to the sides 32 and 33, and two wall surfaces 44 and 45 that are orthogonal to the pair and the surfaces of the inclined portions 34 and 35. Cutting edges 39 and 39a each having an inclined blade 39b are provided (therefore, the movable blade of the punch 27 has an inclined blade 29b in a part thereof). The inclined blade 39b includes first and second partial inclined blades 42 and 43 that intersect at the center.

Further, as shown in FIG. 6 (C), the blade edge angle δ (that is, the wall surface 36 and the wall surfaces 44, 45 intersect) at the blade tip tips (intersections between the inclined portions 34, 35 and the wall surfaces 44, 45) of the blade edges 39, 39a. The angle between the contour line 40 existing along the region to be moved and the first partially inclined blade 42 and the contour line 41 existing along the region where the wall surface 37 and the wall surfaces 44, 45 intersect with the second partially inclined blade 43. Is an acute angle, for example, 30 degrees or more and 89 degrees or less. Therefore, in order to perform punching of one pattern constituting the iron core piece by sequentially operating the inclined blades 39b on the two overlapping strips 12 and 13, in order to perform punching processing of one pattern constituting the iron core piece, the tip and bottom 31 of the blade tips 39 and 39a. Since the step T between them is Ltan (90-δ) when the length of one side of the punch 27 is 2L, at least the total thickness 2t ( It is necessary to set to nt) when n sheets of strips having a thickness t are stacked.
The angle 90-δ is an intersection angle between the surfaces of the inclined portions 34 and 35 and a plane (straight line) orthogonal to the punching direction of the punch 27, and is also called a shear angle.

Further, the clearance set between the fixed blade of the die and the movable blade of the punch used when punching and forming the iron core piece from one strip material 12, 13 is 7 to 11 of the thickness of the strip material 12, 13. %, The clearance c between the fixed blade of the die 26 and the movable blade of the punch 27 is 3.5 to 5.5% of the thickness t of the strips 12 and 13 as shown in FIG. Set to a range of 5%.
Here, the movable blade includes the inclined blade 39b in addition to the straight blade, and the clearance between them and the fixed blade of the die 26 is the same.

As shown in FIG. 5A, when the two strips 12 and 13 are placed on the die 26 and the punch 27 is lowered from above, the cutting edges 38, 38a, 39, and 39a are the strips 12. At this time, a sagging portion 46 (see FIG. 7) is formed in the surface layer side region of the strip plate material 12. Here, the action of the inclined blades 39b of the blade edges 39, 39a and the strip plate members 12, 13 is the same as the inclined blades 24, 25 and the strip plate members 12, 13 described in the punching method of the iron core piece according to the first embodiment. Since it is the same as the operation of, description is omitted.

On the other hand, in the cutting edges 38 and 38a of the punch 27, the cutting edge angles of the cutting edges 38 and 39 with which the punch 27 first comes into contact with the band plate 12 are right angles (90 degrees) in the straight blades whose sides 32 and 33 are the leading edges. Thus, the action portions of the movable blade of the punch 27 acting with the fixed blade of the die 26 are always sides 32 and 33. For this reason, as shown in FIG. 7, when the sides 32 and 33 bite into the strip 12, plastic deformation (shear deformation) of the material existing ahead of the sides 32 and 33 is promoted, and the sides 32 and 33 become stripped. Further bite into the plate 12 (shearing portion 47 is formed). When the punch 27 is further lowered, the material constituting the band plate material 12 is gradually work-hardened, so that the shearing force acting on the band plate material 12 is increased and the tensile strain of the material existing on the front side of the sides 32 and 33 is increased. The tensile strain reaches the amount of tensile strain when the tensile breakage occurs in the band plate material 12, and the fracture portion 48 is formed in the back surface side region (the band plate material 13 side region) of the band plate material 12. As 32 and 33 penetrate the strip plate material 12, burrs 49 are formed on the back side of the strip plate material 12.

Further, since the band plate material 13 is deformed integrally with the band plate material 12, the tensile strain in the band plate material 13 also reaches the tensile strain amount when the tensile breakage occurs in the band plate material 13. The cutting edge tip (sides 32, 33) of the punch 27 that penetrates penetrates the strip plate 13 at a stretch. For this reason, many broken parts 50 are formed in the strip 13 and burrs 51 are formed on the back surface side (die 26 side). Here, the clearance c between the fixed blade of the die 26 and the wall surfaces 36 and 37 of the punch 27 is set in the range of 3.5 to 5.5% of the thickness t of the strips 12 and 13. For this reason, the protrusion length (vertical burr height) along the punching direction of the burr 51 formed on the band plate material 13 can be reduced as compared with the conventional case.
As a result, in the square hole 28 shown in FIG. 5 (B), the processing surface 52 processed by the inclined blade 39b has many shearing portions, and the sides 32 and 33 are processed by a straight blade whose tip is the tip of the blade. The processed surface 53 has a rupture portion and burrs. In particular, the vertical burr height of the burrs 51 formed on the band plate material 13 can be reduced, and the state of the inner peripheral surface of the square hole 28 is compared with the conventional one. Can be greatly improved.

As shown in FIGS. 5 (A) and 5 (B), a die 26 and a punch 27 are used to punch and form a square hole 28 by stacking two 0.25 mm thick strips 12 and 13. The height of the vertical burr existing on the processed surface 53 of the square hole 28 formed in the band plate material 13 arranged on the side was determined. Here, the clearance between the fixed blade of the die 26 and the movable blade of the punch 27 was varied in the range of 1 to 10% with respect to the thickness of the strips 12 and 13.
In the case of punching and forming an iron core piece from one strip material, the clearance between the fixed blade of the die and the movable blade of the punch is set to 10% with respect to the thickness of the strip material.

The effect of clearance on the vertical burr height is shown in FIG. As shown in FIG. 8, when the clearance is set to 4% with respect to the thickness of the strip material, the average value of the vertical burr height is 36 μm, and the vertical length of the burrs formed on the strip material arranged on the die side is shown. It was confirmed that the burr height can be reduced.

As described above, the present invention has been described with reference to the embodiment. However, the present invention is not limited to the configuration described in the above-described embodiment, and the matters described in the scope of claims. Other embodiments and modifications conceivable within the scope are also included.
Further, the present invention also includes a combination of components included in the present embodiment and other embodiments and modifications.
For example, in the second embodiment, the cutting edge with which the punch first comes into contact with the workpiece plate is configured with a cutting edge angle perpendicular to that with an acute angle, but the cutting edge angle may be all acute.
In the second embodiment, the straight blade is used as the linear blade. However, a curved blade or a curved blade that simultaneously contacts the workpiece plate first may be used.
Further, the number of stacked processed plates is not limited to two, and may be three or more.

10: Die, 11: Punch, 12, 13: Strip plate material, 14: Round hole, 15, 16: Cutting edge, 17, 18: Cutting edge tip, 19: Bottom, 20, 21: Inclined portion, 24, 25: Inclined blade 26: Die, 27: Punch, 28: Square hole, 29, 30: Midpoint, 31: Bottom part, 32, 33: Side, 34, 35: Inclined part, 36, 37: Wall surface, 38, 38a, 39, 39a: cutting edge, 39b: inclined blade, 40, 41: contour line, 42: first partially inclined blade, 43: second partially inclined blade, 44, 45: wall surface, 46: sag portion, 47: shear portion, 48: fracture part, 49: burr, 50: fracture part, 51: burr, 52, 53: machined surface, 54: sagging part, 55: shear part, 56: fracture part, 57: burr

Claims (6)

In the punching method of the core piece for punching and forming the core piece from a plurality of workpiece plates arranged in a stacked manner, using a fixedly arranged die and a punch paired with the die,
The angle of the edge of the edge of the edge where the punch first comes into contact with the work plate is an acute angle, and the inclined edge intersects with the edge of the fixed edge of the die at all or a part of the movable edge of the punch. And the punch has a bottomed bottom that is recessed in the axial direction of the punch with respect to the tip of the cutting edge,
The level difference between the tip of the blade edge and the bottom is set to at least nt when punching n sheets of the work plate having a thickness t,
The inclined blade sequentially applied to the target plate of n ply, to form the shearing section on the respective target plate performs punching of the core pieces, the bottom the die side of the cutting edge of the punch A method of punching an iron core piece characterized by penetrating. 2. The punching method of an iron core piece according to claim 1, wherein all of the cutting edges of the punch are the inclined blades, and the punch has two of the cutting edges that are in contact with the work plate. The punching method of the iron core piece. 2. The punching method for an iron core piece according to claim 1, wherein the cutting edge of the punch has a linear blade that simultaneously contacts the inclined blade and the work plate at the same time. 4. The punching method for an iron core piece according to claim 3, wherein two of the linear blades are provided facing each other. In the punching method of the iron core piece according to any one of claims 1 to 4, when performing punching of the two processed plates, the thickness of each processed plate is set to 0.1 mm or more and 0.0. A method for punching an iron core piece, characterized in that the cutting edge angle is set to 30 degrees or more and 89 degrees or less while being 5 mm or less. In the punching method of the core piece for punching and forming the core piece from a plurality of workpiece plates arranged in a stacked manner, using a fixedly arranged die and a punch paired with the die,
The cutting edge angle at the tip of the cutting edge where the punch first comes into contact with the workpiece plate is an acute angle, and the whole or a part of the movable blade of the punch is inclined so that the cutting edge intersects the cutting edge of the fixed blade of the die. Having a blade, the inclined blade sequentially acts on the plurality of work plates, punching the iron core piece,
In addition, when performing punching of the two processed plates, the thickness of each processed plate is set to 0.1 mm or more and 0.5 mm or less, and the edge angle is formed to 30 degrees or more and 89 degrees or less. And the clearance between the fixed blade of the die and the movable blade of the punch is set in the range of 3.5 to 5.5% of the thickness of the plate to be processed. Method.

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