JP2006042520A - Laminated core and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laminated core and its manufacturing method that make it possible to blank both of stator pieces and rotor pieces from a band steel, to eliminate plate thickness deviation, and also to form a skew. <P>SOLUTION: This laminated core 1, comprising a given number of iron core pieces 1t, etc. laminated by caulking, is provided with annular yokes 2, etc. and a given number of teeth 3, etc, protruding inward from the yokes 2, etc. and further provided with cutting portions 'c' that separate the annular yokes 2 to develop them into arbitrary shapes and a specified number of freely bendable connection portions 'r' from which the teeth 3 protrude, that connect between adjacent yokes 2, 2, and that develop the yokes 2, 2, etc., which are separated by the cutting portions 'c' when coils are wound on each teeth 3, into arbitrary shapes. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

    The present invention relates to a laminated iron core manufactured by taking a stator piece from a strip-shaped steel plate, and laminating and bonding the same, and a method for producing the laminated iron core.

    Conventionally, in the stator core, as disclosed in Patent Document 1, the connecting unit plates 105a and 105b are punched out from the rolled steel plate w shown in FIG.

  When this outer shape punching is performed, the die attached to the rotary die 128 is rotated 180 degrees for each predetermined number of sheets so that one connection unit plate 105a and the other connection unit plate 105b are stacked.

  By laminating in this way, the thickness deviation generated along the width direction of the rolled steel sheet w is offset, and the unit laminated body 100 having a uniform stacked thickness shown in FIG. 12A is manufactured.

Since this unit laminated body 100 is arranged in a straight line through the connecting portions 104, each connecting portion 104 is bent into the annular stator core 200 shown in FIG.
Japanese Patent Laid-Open No. 9-2106020

    By the way, since the connecting unit plates 105a and 105b constituting the above-described stator core 200 are usually taken along the width direction of the rolled steel sheet w as a material as shown in FIG. There is a problem that production must be performed, productivity is low, and production costs including mold costs are soaring.

  Further, in this stator core 200, as shown in FIG. 11, in order to eliminate the plate thickness deviation that occurs in the production of the material, the outer die is removed by 180 in the outer shape removing process every predetermined number of the connecting unit plates 105a and 105b. However, a large die rotation mechanism is required to rotate the linear iron core.

  Further, in the above-described annular stator core 200, it is difficult to form a skew.

  In view of the above-described situation, the present invention provides a laminated core and a method for manufacturing a laminated core, in which both a stator piece and a rotor piece can be stripped from a strip-shaped steel sheet, thickness deviation can be eliminated, and skew can be formed. For the purpose of provision.

    In order to achieve the above object, a laminated core according to claim 1 of the present invention is formed by caulking and laminating a predetermined number of core pieces, and a ring-shaped yoke portion and a predetermined number of teeth protruding inward of the yoke portion. A laminated iron core comprising: a cutting part that separates the ring-shaped yoke part to develop it into an arbitrary shape; and a tooth part that protrudes and connects between adjacent yoke parts, And a predetermined number of flexible connecting portions that expand the yoke portion separated by the cutting portion into an arbitrary shape when the coil is wound around the tooth portion.

  The laminated iron core according to claim 2 of the present invention is the laminated iron core according to claim 1, wherein each of the adjacent yokes protrudes while a cutting portion and a tooth portion are separated to expand the ring-shaped yoke portion into an arbitrary shape. An annular iron core piece having a predetermined number of flexible connecting parts for connecting the parts, a tooth part corresponding to each tooth part of the annular iron core piece, and each yoke part from which the tooth part of the annular iron core piece protrudes And a split iron core piece having a yoke portion corresponding to a predetermined number of the core core pieces and a plurality of the core iron pieces being laminated and crimped together.

  The laminated iron core according to claim 3 of the present invention is characterized in that in the laminated iron core according to claim 2, the annular core pieces and the divided core pieces are laminated with a skew angle.

  According to a fourth aspect of the present invention, there is provided a method for manufacturing a laminated iron core, comprising: a predetermined number of core pieces being caulked and laminated; and an annular yoke portion and a predetermined number of teeth portions projecting inwardly of the yoke portion. The ring-shaped yoke portion is separated to expand into an arbitrary shape, and the teeth portion protrudes and the adjacent yoke portions are connected to each other, and when the coils are wound around the teeth portions, A manufacturing method of a laminated core for producing a laminated core comprising a predetermined number of bendable connecting parts that expand a yoke part separated by the cutting part into an arbitrary shape, wherein the rotor is made of a thin plate material. After punching and forming the iron core piece, in the yoke portion forming region for forming the iron core piece, a small hole punching process for forming a small hole continuous to the connecting portion, a cutting line continuous to the small hole, and a cutting line of the cutting portion shear And cutting and pushing back the part formed by the two cutting lines, pushing back the bent part, and punching and forming a predetermined number of slots in the thin plate material. A slot punching step for forming a portion, an inner diameter punching step for punching and forming tooth tips in the predetermined number of teeth portions, and punching out the outer shape of the iron core piece to separate and form the individual iron core pieces. And a caulking laminating step of laminating and laminating on the lower iron core piece previously punched and formed.

    As described above in detail, according to the laminated core according to claim 1 of the present invention, it is easy to manufacture a mold for producing the laminated core.

  Further, the stator iron piece and the rotor iron piece from the thin plate material can be taken together, and the production cost can be reduced.

  In addition, it is possible to rotate and laminate the core pieces to eliminate the thickness deviation of the thin plate material of the core pieces.

  Further, it is possible to skew the laminated iron core, and it is possible to prevent the occurrence of an impact due to a starting torque or the like.

  According to the laminated iron core according to claim 2 of the present invention, the split iron core piece and the annular iron core piece are laminated and caulked and joined to each other, so that the generation of a gap in the laminated iron core accompanying the bending process in the annular iron core piece, It can prevent as much as possible by lamination | stacking of a division | segmentation iron core piece, and generation | occurrence | production of the shape defect of a lamination | stacking iron core can be prevented.

  According to the laminated core according to claim 3 of the present invention, since the annular core piece and the divided core piece are laminated with a skew angle, the laminated iron core is skewed, and an impact due to a starting torque or the like is generated. Can be prevented.

  According to the laminated core according to claim 4 of the present invention, it is easy to manufacture a mold for producing the laminated core.

  Further, the stator iron piece and the rotor iron piece from the thin plate material can be taken together, and the production cost can be reduced.

  Moreover, it is possible to rotate and laminate the iron core pieces, and by rotating and laminating, the thickness deviation of the thin plate material of the iron core pieces can be eliminated, and a laminated iron core having a desired shape can be obtained.

  In addition, a skew angle can be given when the iron core pieces are laminated, and the laminated iron core can be skewed. If the skew is given, an impact due to the torque of the electric motor can be prevented.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  As shown in FIG. 1A of the plan view, a laminated iron core 1 constituting a stator of an electric motor manufactured by using the present invention has yoke portions 2, 2... , And a predetermined number of teeth portions 3, 3... Around which coils (not shown) are wound.

  As shown in the side view of FIG. 1 (b), the laminated iron core 1 has an annular core piece in which yoke portions 2, 2,... And teeth portions 3, 3,. A predetermined number of iron core pieces) 1t are stacked and crimped using crimping portions k, k,.

  The laminated core 1 has a cutting portion c for expanding the yoke portions 2, 2... Into an arbitrary shape and a predetermined number of flexible connecting portions r, r..., And these connecting portions r, r. The yoke portions 2 are connected to each other in a ring shape via the.

  Therefore, during the winding process of the coil to each tooth portion 3, as shown in FIG. 2, which is a development view thereof, the yoke portions 2, 2,... For example, it can be developed linearly.

  As shown in FIG. 1, each of the annular core pieces 1 t constituting the laminated iron core 1 is provided with a circular half-cut crimped portion k for joining to each other, and connects the yoke portion 2. Continuing from the connecting portion r, a connecting small hole r1 is perforated, and further from the connecting small hole r1, a connecting convex portion r2 and a connecting concave portion r3 meeting the connecting convex portion r2 are formed. A cutting line rc is formed.

  These corresponding connecting projections r2 and connecting recesses r3 are in contact with each other, so that the yoke portions 2 are adjacent to each other and have an annular shape.

  The annular core piece 1t has a cutting line cl that forms a cutting projection c1 and a cutting recess c2 that meets the cutting projection c1 as a cutting portion c that separates the yoke portions 2 and 2. In the radial direction. When the cutting projection c1 and the cutting recess c2 come into contact with each other, the adjacent yoke portions 2 and 2 are adjacent to each other with the cutting portion c interposed therebetween.

  By forming such cut portions c and a predetermined number of connecting portions r in each annular core piece 1t, when winding the coil to each tooth portion 3 of the laminated core 1 in which the annular core pieces 1t are laminated, As shown in FIG. 2, the laminated core 1 can be developed into an arbitrary shape by separating the laminated core 1 at the cutting portion c and bending each connecting portion r, and the winding process can be performed smoothly and easily. .

  Next, a method for manufacturing the laminated core 1 having the above-described configuration will be described with reference to FIGS.

  3 to 5 are plan views of the strip steel plate (thin plate material) W in the processing step, and the progressive die apparatus for manufacturing the laminated core 1 includes a small hole punching station S1, a cutting and pushback station S2, A cutting and bending surface beating station S3, a slot removing station S4, a first caulking part forming station S5, a second caulking part forming station S6, an inner diameter punching station S7, and a blank punching and rolling station S8 are provided.

  In this progressive die apparatus, a processing station for manufacturing a rotor core (not shown) by sequentially forming rotor core pieces (not shown) prior to the above-described stations S1 to S8. And the rotor core and the stator core are manufactured by a common progressive mold apparatus.

  That is, the material of the rotor core piece formed by stacking the rotor cores and the annular core piece 1t constituting the stator core 1 is taken on the same strip steel plate W.

  First, prior to each step, a strip steel plate W is prepared, and as a previous step, a rotation that constitutes the rotor core in the central region of the annular core pieces 1t, 1t,... The material of the core iron piece is taken, and a round hole-shaped opening O is formed.

Subsequently, the process proceeds to the manufacturing process of the laminated iron core 1, and first, in the small hole punching station S1, the connecting portions r, r,... A predetermined number (seven in the embodiment) of connecting small holes r1, r1,. (Small hole extraction process)
Next, in the cutting and pushback station S2, between the adjacent yoke portion 2 forming regions in each annular core piece 1t forming region, a connecting convex portion r2 and a connecting concave portion r3 meeting the connecting convex portion r2 are provided. , And a predetermined number of cutting lines rc,..., And one cutting line cl that forms the cutting convex part c1 and the cutting concave part c2 associated with the cutting convex part c1 are shear-separated and connected convex part .., r2 and the cutting projection c1 are bent.

  That is, a shearing process and a bending process are performed on the connecting convex part r2,..., And the cutting convex part c1 of the cutting part c shown by the hatched part in FIG. 6, which is a plan view of the annular core piece 1t.

  Subsequently, the bent connecting projections r 2,... And the cutting projection c 1 are pushed back so as to be flush with the strip steel plate W.

That is, in the cutting and pushing back station S2, the strip steel plate W is sheared and separated by the lowering of the punch along the cutting lines rc, rc,... After r2, ... and the cutting projection c1 are bent downward, the bent connecting projections r2, ... and the cutting projection c1 are joined to the strip steel plate W by a pushback slider (not shown). Push back to be flush. (Cutting and pushback process)
The shapes of the cutting lines rc, rc,... And the cutting line rc of the cutting part c can be appropriately set without being limited to the embodiment as long as they can be sheared and bent. Needless to say.

  At the cut-bending portion beating station S3, the strip steel plate W is sandwiched between the die and the stripper plate, and the bent connecting convex portion r2, ... and the cut convex portion c1 are faced from above with the lower surface of the stripper plate. Thus, the connecting convex portions r2, ... and the cut convex portion c1 are formed so as to be flush with the belt-like steel plate W.

Thereafter, a predetermined number of slots S, S,... Are punched out around the opening O at the slot removal station S4 shown in FIG. (Slot removal process)
Next, in the first caulking part forming station S5 and the second caulking part forming station S6, the caulking parts k, k,.

  That is, in the first caulking part forming station S5, only the lowermost annular core piece 1t constituting one laminated iron core 1 is drilled with a round hole k1 as a caulking part k in order to fit the caulking meat. In the second crimping portion forming station S6, a circular half punching k2 is performed as the crimping portion k on the annular core piece 1t other than the lowermost layer.

Thereafter, at the inner diameter punching station S7 shown in FIG. 5, the tooth tips 3t in the respective tooth portions 3 are formed by punching. (Inner diameter removal process)
Next, in the blank punching and rolling station S8, the outer diameter of the yoke portion 2 in each annular core piece 1t is punched to form individual annular core pieces 1t.

  And each cyclic | annular core piece 1t, 1t ... formed in the predetermined | prescribed shape is laminated | stacked by rotating 180 degree | times to the cyclic | annular core pieces 1t, 1t ... which were previously formed, and each crimping part Caulking and coupling to each other via k, k.

That is, in the blank punching and stacking station S8, the individual annular core pieces 1t, 1t,... Are punched and formed, and each annular core piece 1t is rotated and stacked by a predetermined number of 180.degree. The laminated iron core 1 shown in FIG. 1 is manufactured by caulking with. (Caulking lamination process)
In the station S8, it is also possible to give a skew angle when laminating each of the annular core pieces 1t, 1t. In this case, the configuration of the crimping portion k needs to be a configuration corresponding to skew (described later).

  In addition, in the station S8, it is possible to stack only by giving a skew angle without rotating and stacking each of the annular core pieces 1t, 1t, etc. Also, each of the annular core pieces 1t, 1t,. The layers may be simply laminated and crimped without giving a skew angle.

  Then, as shown in FIG. 2, the laminated core 1 taken out from the progressive die apparatus is expanded at an arbitrary shape by separating at the cutting portion c and bending each connecting portion r, for example, in a straight line shape. The coil winding process to each tooth portion 3 is performed.

  When this winding process is completed, as shown in FIG. 1 again, the cutting portions c are brought into contact with each other to complete the annular motor stator.

  According to the above configuration, the laminated iron core of this type of stator has been conventionally formed by taking a straight material on a steel plate, but can be manufactured in the same manner as the laminated iron core in the circumferential direction, Mold production becomes easy.

  Further, it is possible to take the material in a form in which a predetermined number of annular core pieces 1t constituting the laminated core 1 are connected in an annular shape as shown in FIGS. 3 to 5, and the same strip steel plate together with the rotor core pieces. The material can be taken on W, so that the laminated iron core 1 of the stator can be manufactured together with the rotor iron core using the same progressive die apparatus.

  Therefore, the cost related to the production of the laminated core 1 such as the reduction of the material cost and the processing cost is reduced, and the production cost of the entire motor including the stator core and the rotor core can be greatly reduced.

  Further, each of the annular core pieces 1t, 1t,... Formed in a predetermined shape is rotated and rotated at an arbitrary angle (for example, 180 °) to the previously formed annular core pieces 1t, 1t,. By joining together, the shape defect of the laminated core 1 caused by the thickness deviation of the material inherent in the strip steel plate W can be eliminated.

  Further, if the laminated core 1 is skewed, it is possible to prevent the generation of a steep torque such as the starting torque of the electric motor, and it is possible to prevent the occurrence of an impact due to the electric motor torque.

  FIG. 7 shows a laminated iron core (laminated iron core according to claim 2) 11 which is a modified example 1 of the laminated iron core 1 described above.

  In the modified example 1, as shown in FIG. 7B in the side view, only the annular core pieces 11t1, 11t2, and 11t3 arranged in the uppermost layer, the middle layer, and the lowermost layer have the same configuration as that of the annular core piece 1t described above. As shown in FIG. 7 (a), the yoke portions 12, 12,... Are separated at the cutting portion c10 and connected in an annular shape via the connecting portions r10.

  The core pieces other than the annular core pieces 11t1, 11t2, and 11t3 are divided core pieces 11t4, 11t4,... Each having a structure in which the yoke portions 12 having the tooth portions 13 are separated from each other.

  These divided core pieces 11t4, 11t4,... And the upper, middle and lower annular core pieces 11t1, 11t2, 11t3 are caulked and joined by caulking portions k10,.

  According to the above configuration, the connecting convex portions r12,... And the connecting portion r10 of the upper, middle, and lower annular core pieces 11t1, 11t2, and 11t3 are deformed to some extent by bending, and these annular core pieces. When only 11t1, 11t2, and 11t3 are laminated, a gap is generated between the laminated cores.

  On the other hand, since the core pieces other than the upper, middle, and lower annular core pieces 11t1, 11t2, and 11t3 are the divided core pieces 11t4, 11t4,..., They are bent without the connecting convex portion r12 and the connecting portion r10. Will not be deformed.

  Therefore, by laminating the annular core pieces 11t1, 11t2, 11t3 and the divided core pieces 11t4, 11t4,..., The flat structure of the strip steel plate W can be held as much as possible, and the occurrence of gaps between the laminated cores is obviated. Can be prevented.

  In the first modification, the case where the annular core pieces 11t1, 11t2, and 11t3 are arranged in the uppermost layer, the middle layer, and the lowermost layer of the laminated iron core 11 is illustrated. However, the annular core pieces 11t1, 11t2, and 11t3 can be arranged only in the uppermost layer and the lowermost layer. Alternatively, it can be arranged only on one of the uppermost layer and the lowermost layer.

  Also in this case, there is an effect that the generation of a gap between the laminated cores can be prevented in advance.

  FIG. 8 shows a laminated iron core 21 which is a modified example 2 of the laminated iron core 1 described above.

  In the second modification, as shown in FIG. 8A of the plan view, an annular core piece 21t1 constructed in the same manner as the annular core piece 1t of the laminated core 1, and each connecting projection r221 in the annular core piece 21t1. And a cutting line rc21, rc21,... Forming a connecting concave part r221 and a connecting concave part r232 formed opposite to the cutting line rc21, rc21,. As shown in the side view of FIG. 8 (b), the annular core pieces 21t2 having rc22, rc22,... are alternately stacked and crimped and joined by crimping portions k20,.

  In addition, the cutting line cl which forms the cutting convex part c21 which is the cutting part c20, and the cutting concave part c22 which meets the cutting convex part c21 is formed in the same shape in both the annular core piece 21t1 and the annular core piece 21t2. .

  Also in this laminated iron core 21, at the time of the coil winding process to the tooth part 23, the yoke part 22 can be separated by the cutting part c20 and developed into an arbitrary shape via the connecting parts r20, r20,. .

  9 and 10 show a laminated core (laminated core of claim 3) 31 which is a modified example 3 of the laminated core 1 described above.

  As shown in FIG. 9 (a) in the plan view and FIG. 9 (b) in the developed plan view, the laminated core 31 of Modification 3 is divided into the core pieces (split core pieces in claim 3) 31t2, 31t2,. An annular iron core piece (annular iron core piece of claim 3) 31t1 is laminated with a skew angle, and is caulked and joined by caulking portions 30,.

  In this laminated core 31, the annular core piece 31t1 arranged in the lowermost layer has a configuration similar to the annular core piece 1t of the laminated core 1, and the yoke portion 32 is connected in a ring shape via a predetermined number of connecting portions r30. Has been.

  As shown in FIGS. 9B and 10A, the core pieces other than the lowermost layer are divided core pieces 31t2, 31t2,..., Each having a yoke portion 32 having a teeth portion 33, each divided. Has been.

  As shown in FIG. 9, the caulking portion k30 used for joining these iron core pieces forms a skew throwing hole k31, and the divided iron core pieces 31t2, 31t2,. Bending is performed and a hole for inserting the claw portion k32 is formed only in the lowermost annular core piece 31t1.

  The laminated core 31 is manufactured by laminating a predetermined number of divided core pieces 31t2, 31t2,... Of a divided structure on the lowermost annular core piece 31t1 with a skew angle, and caulking and joining at a crimping portion k30. .

  When winding a coil around the teeth portion 33 of the laminated core 31, the coil is developed from the state shown in FIG. 9A as shown in FIG. 9B to have an arbitrary shape such as a straight line shown in FIG. be able to.

  According to the above configuration, since the laminated iron core 31 is skewed, it is possible to prevent the start-up torque of the motor from being sharply generated and to prevent the occurrence of an impact due to the torque of the motor.

  In addition, in the laminated core 31 of the modification 3, although the case where the lowermost core piece was made into the connection structure was illustrated, it replaces with the lowermost core piece, and it is good also considering the uppermost layer core piece as a connection structure.

  The present invention can be effectively used for components similar to the stator of an electric motor.

(a) And (b) is the top view and side view which show the laminated iron core of the Example in connection with this invention. The top view which shows the state which expand | deployed the laminated iron core of the Example in connection with this invention. The top view of the strip | belt-shaped steel plate which shows the manufacturing process in each station of the progressive die apparatus which manufactures the laminated iron core of the Example in connection with this invention. The top view of the strip | belt-shaped steel plate which shows the manufacturing process in each station of the progressive die apparatus which manufactures the laminated iron core of the Example in connection with this invention. The top view of the strip | belt-shaped steel plate which shows the manufacturing process in each station of the progressive die apparatus which manufactures the laminated iron core of the Example in connection with this invention. The enlarged plan view which shows the site | part by which the cutting bending in the annular core piece of the Example in connection with this invention is performed. (a) And (b) is the top view and side view which show the laminated iron core of the modification 1 of the Example in connection with this invention. (a) And (b) is the top view and side view which show the laminated iron core of the modification 2 of the Example in connection with this invention. (a) And (b) is a top view which shows the laminated iron core of the modification 3 of the Example in connection with this invention, and the top view which shows the state which expand | deployed this laminated iron core. (a) And (b) is the top view and side view which show the state which expand | deployed linearly the laminated core of the modification 3 of the Example in connection with this invention. The top view which shows the process of manufacturing the conventional unit laminated body. (a) And (b) is a perspective view which shows the shape of the unit laminated body shape | molded with the conventional progressive mold apparatus, and the perspective view which shows the shape of the cyclic | annular core product manufactured by winding the conventional unit laminated body Figure.

Explanation of symbols

1, 21 ... laminated iron core (laminated iron core according to claims 1 and 4),
11 ... laminated iron core (laminated iron core of claim 2),
31 ... laminated iron core (laminated iron core of claim 3),
2, 22 ... Yoke part (yoke part of claims 1 and 4),
12. The yoke part of claim 2,
3, 23 ... teeth part (the teeth part of claims 1 and 4),
13. The teeth part according to claim 2,
3t ... tooth tip,
1t, 2 1t1... Annular core pieces (iron pieces of claims 1 and 4),
11t1, 11t2, 11t3 ... annular core pieces (annular core pieces of claim 2),
11t4 ... split core piece (split core piece of claim 2),
31t1 ... annular core piece (annular core piece of claim 3),
31t2 ... split core piece (split core piece of claim 3),
c, c20 ... cutting part (the cutting part of claims 1 and 4),
c1 ... cutting convex part (part formed by the cutting line of the cutting part of claim 4),
c10 ... cutting part (cutting part of claim 2),
cl: a cutting line for forming a cutting convex part and a cutting concave part (the cutting line of the cutting part of claim 4),
r, r20 ... connecting part (the connecting part of claims 1 and 4),
r1 ... Small hole for connection (small hole),
r2 ... Convex protrusion (part formed by a cutting line continuous with the small hole of claim 4),
r10 ... connection part (connection part of claim 2),
rc ... cutting line (cutting line continuous to the small hole of claim 4) forming the connecting convex part and the connecting concave part,
S ... Slot,
W: Strip steel plate (thin plate material).

Claims (4)

A laminated iron core comprising a predetermined number of core pieces crimped and laminated, and comprising a ring-shaped yoke portion and a predetermined number of teeth portions projecting inwardly of the yoke portion,
A cutting part for separating the ring-shaped yoke part in order to expand it into an arbitrary shape;
The teeth portion protrudes and connects between adjacent yoke portions, and a predetermined number of bendable shapes that unfold the yoke portions separated at the cutting portion when the coils are wound around the teeth portions into an arbitrary shape. A laminated iron core comprising: a connecting portion. In the laminated iron core according to claim 1,
An annular core piece having a predetermined number of flexible connecting portions that project between a cutting portion that separates the ring-shaped yoke portion in order to expand it into an arbitrary shape and a tooth portion and connects between adjacent yoke portions;
A divided core piece comprising a tooth portion corresponding to each tooth portion of the annular core piece and a yoke portion corresponding to each yoke portion from which the teeth portion of the annular core piece protrudes;
A predetermined number of the annular core pieces and the divided core pieces are laminated and crimped and joined together. The laminated core according to claim 2, wherein the annular core pieces and the divided core pieces are laminated with a skew angle. In order to develop a ring-shaped yoke portion into an arbitrary shape, comprising a predetermined number of iron core pieces and a ring-shaped yoke portion and a predetermined number of teeth portions protruding inward of the yoke portion. The cutting part to be separated and the teeth part protrude from each other and the adjacent yoke parts are connected to each other, and the yoke part separated by the cutting part at the time of coil winding to each tooth part is developed into an arbitrary shape. A method for producing a laminated core for producing a laminated core comprising a predetermined number of flexible connecting parts,
After punching and forming the rotor core piece from a thin plate material, in the yoke part forming region for forming the core piece, a small hole punching process for forming a small hole continuous to the connecting part;
A cutting and pushing back process for shearing and separating the cutting line continuous to the small hole and the cutting line of the cutting portion, bending the part formed by the two cutting lines, and pushing back the bent part,
Slotting step of forming a predetermined number of teeth by punching a predetermined number of slots in the thin plate material;
An inner diameter punching process for punching and forming tooth tips in the predetermined number of teeth portions;
A caulking laminating step of punching out the outer shape of the iron core pieces to separate and forming individual iron core pieces, and laminating the iron core pieces on a lower iron core piece formed by punching first and caulking and bonding,
A method for producing a laminated iron core, comprising:

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