METHOD FOR PRODUCEING A LAMINATED IRON CORE AND DEVICE FOR PRODUCEING A LAMINATED IRON CORE

Description

Technical Field

[0001] The present disclosure relates to a method of manufacturing a stacked core and an apparatus for manufacturing a stacked core.Background Art

[0002] A stacked stator core is a part that constitutes a motor. A stacked stator core is obtained by stacking and fastening a plurality of metal plates (for example, electrical steel sheets) processed in a predetermined shape. A stacked stator core typically has a ring-shaped yoke portion and a plurality of tooth portions protruding from the inner edge of the yoke portion toward the center of the yoke portion. In order to produce a motor, a winding coil is wound around each tooth portion with a predetermined number of turns. However, since the distance between adjacent tooth portions is usually narrow, the operation of winding a winding coil around a tooth portion tends to be difficult.

[0003] Patent Literature 1 discloses a method of manufacturing a stacked stator core, including a first step of intermittently feeding a coil material, which is a strip-like metal plate (workpiece plate) wound in a coil shape, from an uncoiler and blanking the metal plate by a punch to form a plurality of blanked members (see Paragraph 0022 and step A in FIG. 4), a second step of stacking the plurality of blanked members to obtain a stack including a yoke portion and tooth portions protruding from the inner edge of the yoke portion toward the center of the yoke portion (see Paragraph 0028 and step B in FIG. 4), a third step of dividing the stack into individual pieces for each tooth portion to form a plurality of core pieces (see Paragraph 0029 and step D in FIG. 4), a fourth step of winding a winding coil around the tooth portion of each core piece (see Paragraph 0029 and step E in FIG. 4), and a fifth step of assembling the core pieces so as to connect the adjacent yoke portions to each other to obtain a ring-shaped stacked core (see Paragraph 0029 and step F in FIG. 4).

[0004] The first step includes blanking a slot-forming portion serving as a slot that is a space formed between adjacent yoke portions from the metal plate (see Paragraph 0024 and step b in FIG. 6), blanking an inner diameter portion serving as a center hole that is a space formed at the center of the stacked stator core 1 from the metal plate (see Paragraph 0024 and step c in FIG. 6), half-blanking a part of a region corresponding to the yoke portion (see Paragraph 0025, step e in FIG. 6, and FIG. 8(a)), pushing back the half-blanked part and press-fitting it into the original position (a position to be worked) of the metal plate (see Paragraph 0026, step f in FIG. 6, and FIG. 8(b)), and blanking an outer shape to obtain a blanked member (see Paragraph 0027 and step g in FIG. 6). A pilot hole is formed in the metal plate before the first step in order to position the metal plate by a pilot pin (retainer pin) in blanking the metal plate by a punch.

[0005] Patent Literature 2 relates to a sequential press processing method, comprising a conveyance process in which multiple strip plates are conveyed in sequence to multiple processing stages while overlapping each other.

[0006] Patent Literature 3 relates to a laminated stator core and a manufacturing method thereof. The method includes producing a plurality of core sheets from a strip, ends of the strip being a part of a product without being cut twice, and rotating and laminating the core sheets.

[0007] Patent Literature 4 describes a manufacturing method for punching and processing iron cores of electric motors from strip material using a die with sequential feed method.

[0008] Patent Literature 5 describes an iron core punching method using a temporary pilot hole.

[0009] Patent Literature 6 describes a manufacturing method of iron cores for rotary electric machines.Citation List Patent Literature

[0010] Patent Literature 1: Japanese Unexamined Patent Publication No. 2012-010425 Patent Literature 2: Japanese Unexamined Patent Publication No. 2016-226109 Patent Literature 3: US 2010 / 327690 A1 Patent Literature 4: Japanese Unexamined Patent Publication No. 2006-280017 Patent Literature 5: Japanese Unexamined Patent Publication No. 2001-190048 Patent Literature 6: Japanese Unexamined Patent Publication No. S64-77437 Summary of Invention Technical Problem

[0011] When a metal plate is half-blanked, the metal plate is deformed by the punch. In particular, a portion of the metal plate that is in contact with the outer peripheral edge of the punch is plastically deformed and slightly stretched. Thus, when the half-blanked portion is pushed back to the position to be worked in the subsequent step, the half-blanked portion is press-fitted into the position to be worked while expanding the metal plate outward in the plane of the metal plate. Accordingly, while the half-blanked portion is firmly fitted in the metal plate to such an extent that is not easily disengaged manually, strain may be generated in the metal plate.

[0012] In the method described in Patent Literature 1, half-blanking and pushing-back are performed after the inner diameter portion is blanked from the metal plate. Thus, even when the inner diameter portion is accurately blanked, the space of the punched inner diameter portion is deformed when undergoing the subsequent half-blanking and pushing-back. Therefore, the finished stacked stator core may not have a shape as designed. Similarly, because of half-blanking and pushing-back, the position of the pilot hole formed in the metal sheet before those workings may also be displaced. If the amount of displacement is large, the pilot pin is unable to be inserted in the pilot hole. Therefore, the positioning of the metal plate by the pilot pin may be failed.

[0013] The present disclosure describes a method of manufacturing a stacked core and an apparatus for manufacturing a stacked core, by which a stacked core can be formed accurately even through the steps of working the metal plate and of press-fitting a worked portion into a position to be worked.Solution to Problem

[0014] A method of manufacturing a stacked core according to an aspect of the present disclosure includes: a first step of forming a first pilot hole in a strip-like metal plate by a first punch; a second step, in a state in which a first pilot pin is inserted into the first pilot hole to position the metal plate, of processing a predetermined portion of the metal plate by a second punch, and of press-fitting a worked portion of the metal plate that is processed by the second punch into the metal plate; a third step of forming a second pilot hole in the metal plate by a third punch, after the second step and before another process is performed on the metal plate; and a fourth step of blanking a region including the worked portion by a fourth punch to form a first blanked member, in a state in which a second pilot pin is inserted into the second pilot hole to position the metal plate, after the third step.

[0015] An apparatus for manufacturing a stacked core according to another aspect of the present disclosure includes a feeder configured to sequentially feed a strip-like metal plate intermittently, first to fourth punches, first and second pilot pins, a drive unit configured to drive the first to fourth punches and the first and second pilot pins, and a control unit. While controlling the feeder and the drive unit to sequentially feed the metal plate intermittently, the control unit performs: a first process of forming a first pilot hole in the metal plate by the first punch; a second process, in a state in which the first pilot pin is inserted into the first pilot hole to position the metal plate, of processing a predetermined portion of the metal plate by the second punch, and of press-fitting a worked portion of the metal plate that is processed by the second punch into the metal plate; a third process of forming a second pilot hole in the metal plate by the third punch, after the second process and before another work is performed on the metal plate; and a fourth process of blanking a region including the worked portion by the fourth punch to form a first blanked member, in a state in which the second pilot pin is inserted into the second pilot hole to position the metal plate, after the third process.Effects of Invention

[0016] With the method of manufacturing a stacked core and the apparatus for manufacturing a stacked core according to the present disclosure, a stacked core can be formed accurately even through the steps of working the metal plate and of press-fitting a worked portion into a position to be worked.Brief Description of Drawings

[0017] FIG. 1 is a perspective view illustrating an example of a stacked stator core. FIG. 2 is a sectional view along line II-II in FIG. 1. FIG. 3 is a top view illustrating a blanked member that constitutes the stacked stator core in FIG. 1. FIG. 4 is a perspective view illustrating an example of a stacked rotor core. FIG. 5 is a schematic diagram illustrating an example of a apparatus for manufacturing a stacked stator core. FIG. 6 is a schematic sectional view illustrating a blanking device cut in a first line. FIG. 7 is a schematic sectional view illustrating the blanking device cut in a second line. FIG. 8 is a sectional view schematically illustrating a mechanism for stacking a blanked member and a mechanism for ejecting a stack from a die. FIG. 9 is a sectional view schematically illustrating a mechanism for stacking a blanked member and a mechanism for ejecting a stack from a die. FIG. 10 is a diagram partially illustrating an exemplary layout of stamping. FIG. 11 is a diagram illustrating a part following FIG. 10 in the layout of stamping. FIG. 12 is a diagram illustrating a part following FIG. 11 in the layout of stamping. Description of Embodiments

[0018] Embodiments according to the present disclosure described below is only by way of illustration for describing the present invention, and the present invention is not limited to the description below.<Embodiment Overview>

[0019] (1) A method of manufacturing a stacked core according to an example of the present embodiment includes: a first step of forming a first pilot hole in a strip-like metal plate by a first punch; a second step, in a state in which a first pilot pin is inserted into the first pilot hole to position the metal plate, of working a predetermined portion of the metal plate by a second punch, and of press-fitting a worked portion of the metal plate that is processed by the second punch into the metal plate; a third step of forming a second pilot hole in the metal plate by a third punch, after the second step and before another process is performed on the metal plate; and a fourth step of blanking a region including the worked portion by a fourth punch to form a first blanked member, in a state in which a second pilot pin is inserted into the second pilot hole to position the metal plate, after the third step. In the method of manufacturing a stacked core according to an example of the present embodiment, in the second step, the worked portion is press-fitted into the position to be worked while expanding the metal plate outward in the plane of the metal plate. Therefore, although the worked portion is firmly fitted in the metal plate to an extent that is not easily disengaged manually, strain may be generated in the metal plate. However, in the method of manufacturing a stacked core according to an example of the present embodiment, in the third step after the second step and before another work is performed on the metal plate, the second pilot hole different from the first pilot hole is formed in the metal plate. Since the second pilot hole is formed in the metal plate deformed by strain, the position of the second pilot hole is not displaced or the amount of displacement of the second pilot hole is very small. Accordingly, in the fourth step, the metal plate can be positioned by inserting the second pilot pin into the second pilot holes, so that the first blanked member formed by blanking the metal plate by the fourth punch can be formed in a shape as designed. As a result, the stacked core can be formed accurately even through the steps of working the metal plate and of press-fitting the worked portion into the position to be worked. (2) In the method according to the section (1) above, in the third step, the second pilot hole having an outer shape larger than that of the first pilot hole may be formed by the third punch at a position in the metal plate that coincides with the first pilot hole. In this case, the second pilot hole is formed so as to overlap the first pilot hole. This eliminates the need for separately reserving a region for forming the second pilot hole in the metal plate. Accordingly, a narrower metal plate can be used, thereby improving the yield. As a result, the production cost for the stacked core can be reduced. In particular, when the entire length of one coil material fed from the uncoiler is, for example, approximately several hundred meters to several tens of thousands of meters, the narrower metal plate very effectively achieves yield improvement and lower cost. (3) The method according to the section (1) or (2) above may further include: a fifth step of blanking a region in the metal plate that corresponds to a slot of a stacked stator core by a fifth punch to form a slot-corresponding hole in the metal plate, after the first step and before the second step; and a sixth step of blanking a region in the metal plate that corresponds to a center hole positioned at a center of a stacked stator core and in which a rotor is disposed, by a sixth punch to form a center-corresponding hole in the metal plate, in a state in which a third pilot pin is inserted into the second pilot hole to position the metal plate, after the third step and before the fourth step. A motor is formed by disposing a rotor in the center hole of a stacked stator core. The gap (or air gap) between the inner peripheral surface of the center hole of the stacked stator core and the outer peripheral surface of the rotor is an important parameter on the characteristics of the motor. In the method according to the section (3), the center-corresponding hole corresponding to the center hole of the stacked stator core is formed in the metal plate in a state in which the third pilot pin is inserted into the second pilot hole to position the metal plate. The center hole of the stacked stator core thus can be formed in a shape as designed. Accordingly, the air gap, which is an important parameter in motors, can be formed very accurately, thereby improving the performance of the motor. (4) The method according to the section (3) above may further include: a seventh step of forming a through hole in the metal plate by a seventh punch, before the second step; and an eighth step of blanking a second blanked member for a stacked rotor core from the metal plate by an eighth punch through a die held by a rotatable die holder, and of stacking the second blanked member on another second blanked member already blanked from the metal plate, after the seventh step and before the second step. In the eighth step, when the second blanked member is stacked on the another second blanked member a fourth pilot pin inserted into the through hole may be engaged in an engagement hole in the rotatable die holder to restrain the rotatable die holder from rotating. The rotatable die holder is configured to be rotatable for the purpose of rotationally stacking the second blanked members. However, if the rotatable die holder rotates when the second blanked members are stacked, the rotational stacking angle is shifted to cause a failure in appropriate rotational stacking. Then, with the method according to the section (4), when the second blanked members are stacked, the fourth pilot pin is engaged in the engagement hole of the rotatable die holder to restrain the rotatable die holder from rotating. This process prevents a shift in rotational stacking angle and therefore, the second blanked members can be stacked appropriately. In addition, the fourth pilot pin is engaged in the engagement hole of the rotatable die holder while being inserted into the through hole formed in the metal plate. This eliminates the need for disposing the fourth pilot pin so as to avoid the metal plate and can achieve downsizing of the apparatus for manufacturing a stacked core, the apparatus including the fourth pilot pin and the rotatable die holder. (5) In the method according to any one of the sections (1) to (4) above, the first blanked member may be formed in each of multiple lines shifted in pitch in a width direction of the metal plate. In such multiple line arrangement work, the steps of processing the metal plate and of press-fitting the worked portion into the position to be worked cause an even greater strain in the metal plate. The position of the first pilot hole thus may be significantly displaced. However, in the method according to the section (5), the second pilot hole is also formed in the metal plate deformed by strain, and the subsequent work on the metal plate is performed in a state in which the second pilot pin is inserted into the second pilot hole. Therefore, even in the multiple line arrangement work in which the metal plate is more likely to be deformed, the stacked core can be formed accurately. (6) An apparatus for manufacturing a stacked core according to another example of the present embodiment includes a feeder configured to sequentially feed a strip-like metal plate intermittently, first to fourth punches, first and second pilot pins, a drive unit configured to drive the first to fourth punches and the first and second pilot pins, and a control unit. While controlling the feeder and the drive unit to sequentially feed the metal plate intermittently, the control unit performs: a first process of forming a first pilot hole in the metal plate by the first punch; a second process, in a state in which the first pilot pin is inserted into the first pilot hole to position the metal plate, of working a predetermined portion of the metal plate by the second punch, and of press-fitting a worked portion of the metal plate that is processed by the second punch into the metal plate; a third process of forming a second pilot hole in the metal plate by the third punch, after the second process and before another work is performed on the metal plate; and a fourth process of blanking a region including the worked portion by the fourth punch to form a first blanked member, in a state in which the second pilot pin is inserted into the second pilot hole to position the metal plate, after the third process. The apparatus for manufacturing a stacked core according to another example of the present embodiment achieves the similar effects as the method according to the section (1) above. (7) In the apparatus according to the section (6) above, the control unit may cause the third punch to form the second pilot hole having an outer shape larger than that of the first pilot hole at a position in the metal plate that coincides with the first pilot hole, in the third process. In this case, the similar effects as in the method according to the section (2) above can be achieved. (8) The apparatus according to the section (6) or (7) above may further include a third pilot pin, and fifth and sixth punches. The control unit may control the drive unit to further perform: a fifth process of blanking a region in the metal plate that corresponds to a slot of a stacked stator core by the fifth punch to form a slot-corresponding hole in the metal plate, after the first process and before the second process; and a sixth process of blanking a region in the metal plate that corresponds to a center hole positioned at a center of a stacked stator core and in which a rotor is disposed, by the sixth punch to form a center-corresponding hole in the metal plate, in a state in which the third pilot pin is inserted into the second pilot hole to position the metal plate, after the third process and before the fourth process. In this case, the similar effects as in the method according to the section (3) above can be achieved. (9) The apparatus according to the section (8) above may further include seventh and eighth punches, a fourth pilot pin, and a rotatable die holder having an engagement hole configured to be engaged with the fourth pilot pin. The control unit may control the drive unit to further perform: a seventh process of forming a through hole in the metal plate by the seventh punch before the second process; and an eighth process, in a state in which the fourth pilot pin is inserted into the through hole and engaged in the engagement hole to restrain the die holder from rotating, of blanking a second blanked member for a stacked rotor core from the metal plate by the eighth punch through a die held by the rotatable die holder, and of stacking the second blanked member on another second blanked member already blanked from the metal plate, after the seventh process and before the second process. In this case, the similar effects as in the method according to the section (4) above can be achieved. (10) In the apparatus according to any one of the sections (6) to (9) above, the first blanked member may be formed in each of multiple lines shifted in pitch in a width direction of the metal plate. In this case, the similar effects as in the method according to the section (5) above can be achieved. <Illustrative Examples of Embodiments>

[0020] An exemplary embodiment according to the present disclosure will be described in more detail below with reference to the drawings. In the following description, the same elements or the elements having the same functions are denoted by the same reference signs and an overlapping description will be omitted.[Configuration of Stacked Stator Core]

[0021] First of all, referring to FIG. 1 and FIG. 2, a configuration of a stacked stator core 1 is described. A stacked stator core 1 is a part of a stator. The stator has windings attached to the stacked stator core 1. The stator is combined with a rotor to form a motor. As illustrated in FIG. 1, the stacked stator core 1 has a cylindrical shape. More specifically, a through hole 1a (center hole) extending along a center axis Ax1 is provided in the center part of the stacked stator core 1. A rotor can be disposed in the through hole 1a.

[0022] The stacked stator core 1 is a stack in which a plurality of blanked members W1 (first blanked members) are stacked. The blanked members W1 each are a plate-shaped part formed by blanking an electrical steel sheet ES (metal plate) described later into a predetermined shape. The stacked stator core 1 may be formed by rotational stacking. "Rotational stacking" refers to stacking the blanked members W1 while relatively shifting the angle between the blanked members W1. The rotational stacking is performed mainly for cancelling the plate thickness deviations of the stacked stator core 1. The angle of rotational stacking may be set to a desired value.

[0023] The stacked stator core 1 has a yoke portion 11, a plurality of tooth portions 12, and a plurality of connecting tab portions 13. The yoke portion 11 has an annular shape and extends so as to surround the center axis Ax1. The width in the radial direction, the inner diameter, the outer diameter, and the thickness of the yoke portion 11 can each be set to a variety of values according to the purpose and performance of the motor.

[0024] Each tooth portion 12 extends along the radial direction of the yoke portion 11 from the inner edge of the yoke portion 11 toward the center axis Ax1. That is, each tooth portion 12 protrudes from the inner edge of the yoke portion 11 toward the center axis Ax1. In the stacked stator core 1, twelve tooth portions 12 are formed integrally with the yoke portion 11. The tooth portions 12 are arranged at substantially regular intervals in the circumferential direction of the yoke portion 11. A slot 14 that is a space for disposing a winding (not illustrated) is defined between adjacent tooth portions 12.

[0025] The connecting tab portions 13 are provided at the yoke portion 11 and the tooth portions 12. In the present embodiment, the blanked members W1 adjacent in the stacking direction are fastened to each other by the connecting tab portions 13. Specifically, as illustrated in FIG. 2, the connecting tab portions 13 include a connecting tab 13a formed at a blanked member W1 forming a layer other than the bottom layer of the stacked stator core 1 and a through hole 13b formed at a blanked member W1 forming the bottom layer of the stacked stator core 1. The connecting tab 13a is configured with a depression formed on the front surface side of the blanked member W1 and a projection formed on the back surface side of the blanked member W1. The depression of the connecting tab 13a of one blanked member W1 is joined to the projection of the connecting tab 13a of another blanked member W1 adjacent to the front surface side of the one blanked member W1. The projection of the connecting tab 13a of one blanked member W1 is joined to the depression of the connecting tab 13a of still another blanked member W1 adjacent on the back surface side of the one blanked member W1. The projection of the connecting tab 13a of the blanked member W1 adjacent to the bottom layer of the stacked stator core 1 is joined to the through hole 13b. The through hole 13b has a function of preventing the subsequently formed blanked member W1 from being fastened to the previously produced stacked stator core 1 by the connecting tab 13a when the stacked stator cores 1 are continuously produced.

[0026] The blanked members W1 may be fastened to each other by a variety of known methods, instead of the connecting tab portions 13. For example, the blanked members W1 may be joined to each other, for example, using adhesive or a resin material or joined to each other by welding. Alternatively, the blanked member W1 may be provided with a temporarily-connecting tab, and the stacked stator core 1 may be obtained by fastening the blanked members W1 to each other through the temporarily-connecting tabs to form a stack, and thereafter removing the temporarily-connecting tabs from the stack. The "temporarily-connecting tab" means a connecting tab used for temporarily integrating the blanked members W1 and removed in the process of producing a product (stacked stator core 1).

[0027] Referring now to FIG. 3, the blanked member W1 will be described in more detail. The shape of the blanked member W1 as viewed from the center axis Ax1 direction is substantially the same as the shape of the stacked stator core 1 as viewed from the center axis Ax1 direction. The blanked member W1 therefore also has an annular shape as viewed from the center axis Ax1 direction. A through hole W1a is provided at the center part of the blanked member W1.

[0028] The blanked member W1 has a yoke portion W11 and the tooth portions W12. The yoke portion W11 and the tooth portions W12 are provided with connecting tab portions 13. The yoke portion W11 has an annular shape and extends so as to surround the center axis Ax1. The yoke portion W11 has a plurality of cut lines CL. In the blanked member W1 illustrated in FIG. 2, the yoke portion W11 has twelve cut lines CL.

[0029] Each cut line CL extends along the radial direction of the yoke portion W11 so as to traverse the yoke portion W11. The cut lines CL are arranged at substantially regular intervals in the circumferential direction of the yoke portion W11. The cut lines CL may be formed, for example, by lancing or blanking an electrical steel sheet ES and thereafter pushing back the lanced portion or the blanked portion (the worked portion) and press-fitting it into the original position (the position to be worked) of the workpiece plate. When the electrical steel sheet ES is lanced or blanked, the worked portion is plastically deformed and slightly stretched. Thus, when the worked portion is press-fitted into the position to be worked, the worked portion is firmly fitted in the electrical steel sheet ES to such an extent that is not easily disengaged manually.

[0030] The shape of the cut line CL is not limited to a projecting and depressed shape as illustrated in FIG. 1 and FIG. 2 and may be any other shapes that traverse between the outer peripheral edge and the inner peripheral edge of the yoke portion W11, such as a linear shape, a curved shape, a crank shape, a bow shape, and an arc shape. When the shape of the cut line CL is linear, the cut line CL may extend along the radial direction of the yoke portion W11 or may extend to be inclined at a predetermined angle relative to the radial direction of the yoke portion W11. When the shape of the cut line CL is linear, the yoke portion W11 tends to be easily divided into individual pieces at the cut lines CL, with a small force.

[0031] Each tooth portion W12 extends along the radial direction of the yoke portion W11 from the inner edge of the yoke portion W11 toward the center axis Ax1. That is, each tooth portion W12 protrudes from the inner edge of the yoke portion W11 toward the center axis Ax1. In the present embodiment, twelve tooth portions W12 are formed integrally with the yoke portion W11.

[0032] The tooth portions W12 are arranged at substantially regular intervals in the circumferential direction of the yoke portion W11. Each tooth portion W12 is positioned between adjacent cut lines CL in the circumferential direction of the yoke portion W11. A slot W14 that is a space for disposing a winding is defined between adjacent tooth portions W12.

[0033] When the blanked member W1 is divided into individual pieces at the cut lines CL, a plurality of plate pieces W15 (in FIG. 2, twelve plate pieces W15) are obtained from one blanked member W1. In other words, it can be said that the blanked member W1 is an assembly in which the plate pieces W15 are combined. One plate piece W15 is configured with one yoke piece portion W11a and one tooth portion W12. The yoke piece portion W11a is a part of the yoke portion W11 when the yoke portion W11 is divided by the cut lines CL. The blanked member W1 is therefore integrated by temporarily connecting the plate pieces W15 adjacent in the circumferential direction of the center axis Ax1 at the ends of the yoke piece portions W11a (cut lines CL).

[0034] Returning to FIG. 1, the stacked stator core 1 is formed by stacking the blanked members W1 as described above. More specifically, the blanked members W1 are stacked such that the yoke portions W11, the tooth portions W12, and the cut lines CL overlap each other. Therefore, when a predetermined force is applied to the stacked stator core 1 to divide the stacked stator core 1 into individual pieces at the cut lines CL, a plurality of core pieces 15 (in FIG. 1, twelve core pieces 15) are obtained from the stacked stator core 1. In other words, it can be said that the stacked stator core 1 is also an assembly in which the core pieces 15 are combined. One core piece 15 is configured with one yoke piece portion 11a and one tooth portion 12. The yoke piece portion 11a is a part of the yoke portion 11 when the yoke portion 11 is divided by the cut lines CL. The stacked stator core 1 is therefore integrated by temporarily connecting the core pieces 15 adjacent in the circumferential direction of the center axis Ax1 at the ends of the yoke piece portions 12a (cut lines CL).[Configuration of Stacked Rotor Core]

[0035] Referring now to FIG. 4, a configuration of a stacked rotor core 2 is described. The stacked rotor core 2 is a part of a rotor. The rotor is formed by attaching end plates (not illustrated) and a shaft (not illustrated) to the stacked rotor core 2. The stacked rotor core 2 has a cylindrical shape. More specifically, a through hole 2a (center hole) extending along the center axis Ax2 is provided at the center part of the stacked rotor core 2. A shaft can be disposed in the through hole 2a.

[0036] The stacked rotor core 2 is a stack in which a plurality of blanked members W2 (second blanked members) are stacked. The blanked members W2 each are a plate-shaped part formed by blanking an electrical steel sheet ES (metal plate) described later into a predetermined shape. The stacked rotor core 2 may be formed by rotational stacking in the same manner as the stacked stator core 1. The angle of rotational stacking may be set to a desired value.

[0037] The stacked rotor core 2 has a plurality of connecting tab portions 23. The connecting tab portions 23 include a not-illustrated connecting tab and a through hole and have a function of fastening the adjacent blanked members W2 to each other, in the same manner as the connecting tab portions 13. The blanked members W2 may be fastened to each other by a variety of known methods, instead of the connecting tab portions 23. For example, the blanked members W2 may be joined to each other, for example, using adhesive or a resin material or joined to each other by welding. Alternatively, the blanked member W2 may be provided with a temporarily-connecting tab, and the stacked rotor core 2 may be obtained by fastening the blanked members W2 to each other through the temporarily-connecting tabs to form a stack, and thereafter removing the temporarily-connecting tabs from the stack.

[0038] At least one magnet insertion hole (not illustrated) extending along the center axis Ax2 (stacking direction) and passing through the stack 20 may be provided in the stacked rotor core 2. The magnet insertion hole may be filled with a resin material with a permanent magnet (not illustrated) disposed therein. The resin material has a function of fixing a permanent magnet in the magnet insertion hole and a function of joining the blanked members W2 adjacent in the top-bottom direction to each other.[Apparatus for Manufacturing Stacked Core]

[0039] Referring now to FIG. 5, an apparatus 100 for manufacturing the stacked stator core 1 and the stacked rotor core 2 is described.

[0040] The apparatus 100 is an apparatus for manufacturing the stacked stator core 1 and the stacked rotor core 2 from an electrical steel sheet ES (workpiece plate), which is a strip-like metal plate. The apparatus 100 includes an uncoiler 110, a feeding device 120 (feeder), a blanking device 130, and a controller 140 (control unit).

[0041] The uncoiler 110 rotatably holds a coil material 111 with the coil material 111 attached thereto. The coil material 111 is a strip-like electrical steel sheet ES wound into a coil shape. The feeding device 120 has a pair of rollers 121 and 122 sandwiching the electrical steel sheet ES from above and below. A pair of rollers 121 and 122 rotate and stop based on an instruction signal from the controller 140 and sequentially feed the electrical steel sheet ES intermittently toward the blanking device 130.

[0042] The length of the electrical steel sheet ES that forms the coil material 111 may be, for example, approximately 500 m to 10000 m. The thickness of the electrical steel sheet ES may be, for example, approximately 0.1 mm to 0.5 mm. The thickness of the electrical steel sheet ES may be, for example, approximately 0.1 mm to 0.3 mm in terms of obtaining the stacked stator core 1 and the stacked rotor core 2 having more excellent magnetic characteristics. The width of the electrical steel sheet ES may be, for example, approximately 50 mm to 500 mm.

[0043] The blanking device 130 operates based on an instruction signal from the controller 140. The blanking device 130 has a function of sequentially blanking an electrical steel sheet W intermittently fed by the feeding device 120 to form the blanked members W1 and W2, a function of sequentially stacking the blanked members W1 obtained by blanking to produce the stacked stator core 1, and a function of sequentially stacking the blanked members W2 to produce the stacked rotor core 2.

[0044] The controller 140, for example, generates an instruction signal for operating each of the feeding device 120 and the blanking device 130, based on a program stored in a recording medium (not illustrated) or an operation input from an operator, and transmits the instruction signal to the feeding device 120 and the blanking device 130.[Detail of Blanking Device]

[0045] Referring now to FIG. 5 to FIG. 9, the blanking device 130 is described in more detail. In the present embodiment, the blanking device 130 forms the blanked members W1 and W2 in different lines in the width direction of the electrical steel sheet ES. Specifically, the blanking device 130 forms blanked members 1< W1 and 1< W2 in the first line L1 (see FIG. 10 to FIG. 12) and forms blanked members 2< W1 and 2< W2 in the second line L2 (see FIG. 10 to FIG. 12). In the present description, a numerical superscript " 1< " to the left of a reference sign indicates that the element denoted by the reference sign relates to the first line L1, and a numerical superscript " 2< " to the left of a reference sign indicates that the element denoted by the reference sign relates to the second line L2.

[0046] As illustrated in FIG. 5 to FIG. 7, the blanking device 130 has a base 131, a lower die 132, a die plate 133, a stripper 134, an upper die 135, a top plate 136, a press machine 137 (driver), a suspender 138, punches 1< A1 to 1< A12 and 2< A1 to 2< A12, and pilot pins 1< B1 to 1< B13 and 2< B1 to 2< B13. The base 131 is installed on a floor surface and supports the lower die 132 placed on the base 131.

[0047] The lower die 132 holds the die plate 133 placed on the lower die 132. The lower die 132 has ejection holes 1< C1 to 1< C12 and 2< C1 to 2< C12 to which the material blanked from the electrical steel sheet ES (for example, blanked members W1 and W2, waste material) are ejected, at the positions corresponding to the punches 1< A1 to 1< A12 and 2< A1 to 2< A12, respectively.

[0048] The die plate 133 has a function of forming the blanked members W1 and W2 together with the punches 1< A1 to 1< A12 and 2< A1 to 2< A12. The die plate 133 is provided with dies 1< D1 to 1< D12 and 2< D1 to 2< D12 at the positions corresponding to the punches 1< A1 to 1< A12 and 2< A1 to 2< A12, respectively. In each of the dies 1< D1 to 1< D12 and 2< D1 to 2< D12, a die hole (through hole) is provided, which extends in the top-bottom direction and is communicatively connected with the corresponding one of the ejection holes 1< C1 to 1< C12 and 2< C1 to 2< C12. The size of each through hole is set to such a degree that allows insertion of the tip end of the corresponding one of the punches 1< A1 to 1< A12 and 2< A1 to 2< A12 and is slightly smaller than the tip end.

[0049] As illustrated in FIG. 8 and FIG. 9, the dies 'D5, 1< D12, 2< D5, 2< D12 are held on the inner wall surface of corresponding die holders 133a, each of the die holders 133a having a cylindrical shape. Each of the die holders 133a is attached to the die plate 133 so as to be rotatable around the center axis extending in the vertical direction. Drive mechanisms 133b are connected to the corresponding die holders 133a. The drive mechanisms 133b rotate the corresponding die holders 133a around the center axis of the die holder 133a, based on an instruction signal from the controller 140. Thus, after the cut-out blanked member W1, W2 is stacked on a cylinder 132b, the die holder 133a rotates by a predetermined angle, whereby the following blanked member W1, W2 is rotationally stacked on the preceding blanked member W1, W2. The drive mechanisms 133b may be configured with, for example, a combination of a rotary motor and a gear.

[0050] As illustrated in FIG. 6 and FIG. 7, the die plate 133 is provided with pilot holes 1< E1 to 1< E13 and 2< E1 to 2< E13 at the positions corresponding to the pilot pins 1< B1 to 1< B13 and 2< B1 to 2< B13, respectively. Among them, the pilot holes 1< E3, 1< E12, 2< E4, 2< E12 are provided in the corresponding die holders 133a, as illustrated in FIG. 8 and FIG. 9. For example, in the die holder 133a holding the die 1< D5, a plurality of pilot holes 1< E3 are provided on the upper surface of the die holder 133a so as to be aligned along the outer peripheral edge of the die holder 133a. This is applicable to the pilot holes 1< E12, 2< E4, and 2< E12. The number and the positions of the pilot holes 1< E3, 1< E12, 2< E4, and 2< E12 may be set as appropriate in accordance with the rotational stacking angle of the blanked member W1, W2. For example, when the rotational stacking angle is 120°, three pilot holes are provided on the upper surface side of the die holder 133a, and these three pilot holes may be arranged substantially every 120° in the circumferential direction around the center axis of the die holder 133a.

[0051] The stripper 134 has a function of sandwiching the electrical steel sheet ES with the die plate 133 when the electrical steel sheet ES is blanked with the punches 1< A1 to 1< A12 and 2< A1 to 2< A12 and a function of removing the electrical steel sheet ES sticking to the punches 1< A1 to 1< A12 and 2< A1 to 2< A12 from the punches 1< A1 to 1< A12 and 2< A1 to 2< A12.

[0052] As illustrated in FIG. 6 and FIG. 7, the stripper 134 is provided with through holes extending in the top-bottom direction at the positions corresponding to the punches 1< A1 to 1< A12 and 2< A1 to 2< A12. Each through hole is communicatively connected with a die hole of the corresponding one of the dies 1< D1 to 1< D12 and 2< D1 to 2< D12 when the stripper 134 comes closer to the die plate 133. In the through holes, the lower portions of the punches 1< A1 to 1< A12 and 2< A1 to 2< A12 are inserted. The lower portions of the punches 1< A1 to 1< A12 and 2< A1 to 2< A12 can slide in the through holes.

[0053] The stripper 134 is provided with through holes extending in the top-bottom direction at the positions corresponding to the pilot pins 1< B1 to 1< B13 and 2< B1 to 2< B13. Each through hole is communicatively connected with a corresponding one of the pilot holes 1< E1 to 1< E13 and 2< E1 to 2< E13 when the stripper 134 comes closer to the die plate 133. In the through holes, the lower portions of the pilot pins 1< B1 to 1< B13 and 2< B1 to 2< B13 are inserted. The lower portions of the pilot pins 1< B1 to 1< B13 and 2< B1 to 2< B13 can slide in the through holes.

[0054] The upper die 135 is positioned above the stripper 134. The base portions (upper portions) of the punches 1< A1 to 1< A12 and 2< A1 to 2< A12 and the pilot pins 1< B1 to 1< B13 and 2< B1 to 2< B13 are fixed to the upper die 135. The upper die 135 thus holds the punches 1< A1 to 1< A12 and 2< A1 to 2< A12 and the pilot pins 1< B1 to 1< B13 and 2< B1 to 2< B13.

[0055] The top plate 136 is positioned above the upper die 135. The top plate 136 holds the upper die 135. The press machine 137 is positioned above the top plate 136. The piston of the press machine 137 is connected to the top plate 136 and operates based on an instruction signal from the controller 140. When the press machine 137 operates, the piston extends and retracts so that the stripper 134, the upper die 135, the top plate 136, the suspender 138, the punches 1< A1 to 1< A12 and 2< A1 to 2< A12, and the pilot pins 1< B1 to 1< B13 and 2< B1 to 2< B13 (which hereinafter are collectively referred to as a movable unit 150) move up and down as a whole.

[0056] The suspender 138 has a function of holding the stripper 134 suspended from the upper die 135. The lower end side of the suspender 138 is fixed to the stripper 134. The upper end side of the suspender 138 is attached to the upper die 135 so as to be movable up and down.

[0057] The punches 1< A1 to 1< A12 and 2< A1 to 2< A12 form punch units together with a corresponding dies 1< D1 to 1< D12 and 2< D1 to 2< D12. Each punch unit has the function of blanking the electrical steel sheet ES into a predetermined shape. The punches 1< A1 to 1< A12 are disposed approximately in this order from the upstream side (the feeding device 120 side) toward the downstream side of the blanking device 130. The punches 2< A1 to 2< A12 are disposed approximately in this order from the upstream side (the feeding device 120 side) toward the downstream side of the blanking device 130. The punches 2< A1 to 2< A12 are disposed so as to be roughly aligned with the punches 1< A1 to 1< A12, respectively, in the width direction of the electrical steel sheet ES.

[0058] The pilot pins 1< B1, 'B2, 1< B4 to 1< B13, 2< B1 to 2< B3, and 2< B5 to 2< B13 have a function of pushing the electrical steel sheet ES against the die plate 133 when the electrical steel sheet ES is blanked by the punches 1< A1 to 1< A12 and 2< A1 to 2< A12. The pilot pins 1< B3, 1< B12, 2< B4, and 2< B12 have a function of being engaged with the corresponding pilot holes 1< E3, 1< E12, 2< E4, and 2< E12 to restrain the die holder 133a from rotating. The pilot pins 1< B1 to 1< B13 are disposed so as to be aligned approximately in this order from the upstream side (the feeding device 120 side) toward the downstream side of the blanking device 130. The pilot pins 2< B1 to 2< B13 are disposed so as to be aligned approximately in this order from the upstream side (the feeding device 120 side) toward the downstream side of the blanking device 130. The pilot pins 2< B1 to 2< B13 are disposed so as to be roughly aligned with the pilot pins 1< B1 to 1< B13, respectively, in the width direction of the electrical steel sheet ES.

[0059] As illustrated in FIG. 8, a drive mechanism 132a, a cylinder 132b, a stage 132c, and a pusher 132d are disposed in the ejection hole 1< C5, 2< C5, 1< C12, 2< C12. The drive mechanism 132a drives the cylinder 132b based on an instruction signal from the controller 140. Specifically, the drive mechanism 132a moves the cylinder 132b in the top-bottom direction. The drive mechanism 132a may be configured with, for example, a linear actuator.

[0060] The cylinder 132b has a function of elastically supporting the blanked member 1< W2, 2< W2, 1< W1, 2< W1 cut out from the electrical steel sheet ES by the punch 1< A5, 2< A5, 1< A12, 2< A12. This configuration prevents the cut-out blanked member 1< W2, 2< W2, 1< W1, 2< W1 from dropping downward.

[0061] The controller 140 can instruct the drive mechanism 132a to move the cylinder 132b in the top-bottom direction. Specifically, the cylinder 132b intermittently moves downward every time the blanked member W1, W2 is stacked on the cylinder 132b. Once a predetermined number of the blanked members W1, W2 are stacked on the cylinder 132b to form the stacked stator core 1 or the stacked rotor core 2, as illustrated in FIG. 9, the cylinder 132b moves to the position where the surface of the cylinder 132b is flush with the surface of the stage 132c.

[0062] When the blanked members W1, W2 are stacked on the cylinder 132b, as illustrated in FIG. 8, the tip end of the pilot pin 1< B3, 1< B12, 2< B4, 2< B12 is inserted into the pilot hole 1< E3, 1< E12, 2< E4, 2< E12. The tip end of the pilot pin 'B3, 1< B12, 2< B4, 2< B12 is then engaged in the pilot hole 1< E3, 1< E12, 2< E4, 2< E12 to restrain the die holder 133a from rotating. On the other hand, in other cases, as illustrated in FIG. 9, the pilot pin 1< B3, 1< B12, 2< B4, 2< B12 is on standby above the electrical steel sheet ES. The tip end of the pilot pin 1< B3, 1< B12, 2< B4, 2< B12 is therefore not engaged in the pilot hole 1< E3, 1< E12, 2< E4, 2< E12. Accordingly, in this state, the die holder 133a is rotatable relative to the die plate 133.

[0063] The stage 132c is provided with a hole 132e through which the cylinder 132b can pass. The pusher 132d is configured to be movable in the horizontal direction on a surface of the stage 132c, based on an instruction signal from the controller 140. In a state in which the cylinder 132b moves to a position where the surface of the cylinder 132b is flush with the surface of the stage 132c, the pusher 132d pushes out the stacked stator core 1 or the stacked rotor core 2 from the cylinder 132b onto the stage 132c. The stacked stator core 1 or the stacked rotor core 2 pushed out onto the stage 132c is transported by a not-illustrated conveyor or the like to the subsequent step to produce a stator or a rotor.[Method of Manufacturing Stacked Core]

[0064] A method of manufacturing the stacked stator core 1 and the stacked rotor core 2 will now be described. First of all, referring to FIG. 6 and FIG. 10 to FIG. 12, a method of manufacturing a pair of the stacked stator core 1 and the stacked rotor core 2 by cutting out the blanked members 1< W1 and 1< W2 in the first line L1 of the electrical steel sheet ES will be described.

[0065] When the electrical steel sheet ES is fed to the blanking device 130 by the feeding device 120 and a portion to be worked in the electrical steel sheet ES reaches the punch 1< A1, the controller 140 instructs the press machine 137 so that the press machine 137 pushes the movable unit 150 downward toward the die plate 133. Even after the stripper 134 reaches the die plate 133 and they sandwich the electrical steel sheet ES, the press machine 137 pushes the movable unit 150 downward.

[0066] Here, although the stripper 134 does not move, the tip ends of the punches 1< A1 to 1< A12 and the pilot pins 1< B1 to 1< B13 move in the through holes of the stripper 134 to reach the corresponding dies 1< D1 to 1< D12 and pilot holes 1< E1 to 1< E13 of the die plate 133. Thus, the electrical steel sheet ES is blanked by the punch 1< A1 (first punch, seventh punch) along a predetermined blanked shape, so that a pair of through holes 1< R1a and 1< R1b aligned in the width direction of the electrical steel sheet ES are formed in the electrical steel sheet ES (first step; seventh step; first process; seventh process; see the position 1< P1 in FIG. 6 and FIG. 10). The through hole 1< R1a (first pilot hole) is positioned in the vicinity of the side edge of the electrical steel sheet ES. The through hole 1< R1b (through hole) is positioned in the vicinity of the center of the electrical steel sheet ES. The waste material cut out is ejected from the ejection hole 1< C1 of the lower die 132. Subsequently, the press machine 137 operates to elevate the movable unit 150.

[0067] Next, the electrical steel sheet ES is fed by the feeding device 120, and when a portion of the electrical steel sheet ES to be worked reaches the punch 1< A2, the controller 140 instructs the press machine 137 so that the press machine 137 elevates or lowers the movable unit 150. The electrical steel sheet ES is thus blanked by the punch 1< A2 to form a plurality of through holes 1< R2 in the electrical steel sheet ES (see the position 1< P2 in FIG. 6 and FIG. 10). In the present embodiment, twelve through holes 1< R2 each having a rectangular shape are arranged in a circular shape as a whole. The waste material cut out is ejected from the ejection hole 1< C2 of the lower die 132.

[0068] At the same time, the electrical steel sheet ES may be blanked by the punch 1< A3, if necessary, to form a plurality of through holes 1< R3 in the electrical steel sheet ES (see the position 1< P3 in FIG. 6 and FIG. 10). In the present embodiment, eight through holes 1< R3 each having a circular shape are arranged in a circular shape as a whole inside the region surrounded by the through holes 1< R2. The waste material cut out is ejected from the ejection hole 1< C3 of the lower die 132. Each through hole 1< R3 corresponds to the through hole of the connecting tab portion 23 in the blanked member W2 of the stacked rotor core 2. When the connecting tab in the connecting tab portion 23 is formed, the blanking of the electrical steel sheet ES by the punch 1< A3 is not performed.

[0069] Next, the electrical steel sheet ES is fed by the feeding device 120, and when a portion of the electrical steel sheet ES to be worked reaches the punch 1< A4, the controller 140 instructs the press machine 137 so that the press machine 137 elevates or lowers the movable unit 150. The electrical steel sheet ES is thus blanked by the punch 1< A4 to form one through hole 1< R4 and a plurality of worked areas 1< R5 in the electrical steel sheet ES (see the position 1< P5 in FIG. 6 and FIG. 10). The through hole 1< R4 has a circular shape and corresponds to the through hole 2a in the blanked member W2 of the stacked rotor core 2. The worked area 1< R5 corresponds to the connecting tab of the connecting tab portion 23 in the blanked member W2 of the stacked rotor core 2. In the present embodiment, eight worked areas 1< R5 are arranged in a circular shape to surround the through hole 1< R4. In blanking the electrical steel sheet ES by the punch 1< A4, the pilot pins 1< B1 and 1< B2 are inserted in the through holes 1< R1a, whereby the electrical steel sheet ES is positioned (see the positions 'P4 and 1< P6 in FIG. 6 and FIG. 10).

[0070] When the through holes 1< R3 have already been formed at the position 1< P3 in the electrical steel sheet ES, the part of the punch 1< A4 for forming the worked areas 1< R5 passes through the through holes 1< R3 and misses the electrical steel sheet ES, so that the worked areas 1< R5 are not formed in the electrical steel sheet ES. That is, either of the through holes 1< R3 or the worked areas 1< R5 are selectively formed in the electrical steel sheet ES.

[0071] Next, the electrical steel sheet ES is fed by the feeding device 120, and when a portion of the electrical steel sheet ES to be worked reaches the punch 1< A5 (eighth punch), the controller 140 instructs the press machine 137 so that the press machine 137 elevates or lowers the movable unit 150. The electrical steel sheet ES is thus blanked by the punch 1< A5, and the blanked member 1< W2 having a plurality of connecting tab portions 23 is stacked on the cylinder 132b in the ejection hole 1< C5 (eighth step; eighth process; see the position 1< P7 in FIG. 6 and FIG. 10). The above steps / processes are repeated whereby a plurality of blanked members 1< W2 are stacked on the cylinder 132b while being joined by the connecting tab portions 23 to form the stacked rotor core 2. In blanking the electrical steel sheet ES by the punch 1< A5, the pilot pins 1< B2 and 1< B4 (fourth pilot pin) are inserted into the through holes 1< R1a whereby the electrical steel sheet ES is positioned (see the positions 1< P6 and 1< P9 in FIG. 6 and FIG. 10). Similarly, in blanking the electrical steel sheet ES by the punch 1< A5, the pilot pin 1< B3 (fourth pilot pin) passes through the through hole 2< R1b (described later), and the tip end of the pilot pin 1< B3 is inserted into the pilot hole 1< E3 to restrain the die holder 133a holding the die 1< D5 from rotating (see the position 1< P8 in FIG. 6 and FIG. 10). A through hole 1< R6 is formed in a region in the electrical steel sheet ES where the blanked member 1< W2 has been cut out.

[0072] Next, the electrical steel sheet ES is fed by the feeding device 120, and when a portion of the electrical steel sheet ES to be worked reaches the punch 1< A6 (fifth punch), the controller 140 instructs the press machine 137 so that the press machine 137 elevates or lowers the movable unit 150. The electrical steel sheet ES is thus blanked by the punch 1< A6 to form a plurality of through holes 1< R7 (slot-corresponding holes) in the electrical steel sheet ES (fifth step; fifth process; see the position 1< P11 in FIG. 6, FIG. 10, and FIG. 11). In the present embodiment, twelve through holes 1< R7 each having an approximate sector shape are arranged in a circular shape as a whole. The through hole 1< R7 corresponds to the slot W14 in the blanked member W1 of the stacked stator core 1. The waste material cut out is ejected from the ejection hole 1< C6 of the lower die 132. In blanking the electrical steel sheet ES by the punch 1< A6, the pilot pins 1< B5 and 1< B6 are inserted into the through holes 1< R1a whereby the electrical steel sheet ES is positioned (see the positions 1< P10 and 1< P12 in FIG. 6, FIG. 10, and FIG. 11).

[0073] Next, the electrical steel sheet ES is fed by the feeding device 120, and when a portion of the electrical steel sheet ES to be worked reaches the punch 1< A7 (second punch), the controller 140 instructs the press machine 137 so that the press machine 137 elevates or lowers the movable unit 150. A worked area 1< R8 (worked portion) is thus formed between the through holes 1< R2 and 1< R6 of the electrical steel sheet ES (second step; second process; see the position 1< P13 in FIG. 6 and FIG. 11). The worked area 1< R8 is obtained by lancing or blanking the electrical steel sheet ES along the cut line CL connecting the through holes 1< R2 and 1< R7, and thereafter press-fitting (pushing back) the worked portion into the electrical steel sheet ES. In blanking the electrical steel sheet ES by the punch 1< A7, the pilot pins 'B6 and 1< B7 (first pilot pin) are inserted into the through holes 1< R1a whereby the electrical steel sheet ES is positioned (see the positions 1< P12 and 1< P14 in FIG. 6 and FIG. 11).

[0074] Next, the electrical steel sheet ES is fed by the feeding device 120, and when a portion of the electrical steel sheet ES to be worked reaches the punch 1< A8 (third punch), the controller 140 instructs the press machine 137 so that the press machine 137 elevates or lowers the movable unit 150. The positions coincident with the through holes 1< R1a and 1< R1b of the electrical steel sheet ES are thus blanked by the punch 1< A8, so that a plurality of through hole 1< R9a and 1< R9b (second pilot hole) are formed in the electrical steel sheet ES (third step; third process; see the position 1< P15 in FIG. 6 and FIG. 11). In the present embodiment, the through hole 1< R9a is blanked by the punch 1< A8 at the position coincident with the through hole 1< R1a and has an outer shape larger than that of the through hole 1< R1a. The through hole 1< R9b is blanked by the punch 1< A8 at the position coincident with the through hole 1< R1b and has an outer shape larger than that of the through hole 1< R1b. The waste material cut out is ejected from the ejection hole 1< C8 of the lower die 132.

[0075] Next, the electrical steel sheet ES is fed by the feeding device 120, and when a portion of the electrical steel sheet ES to be worked reaches the punch 1< A9, the controller 140 instructs the press machine 137, if necessary, so that the press machine 137 elevates or lowers the movable unit 150. The electrical steel sheet ES is thus blanked by the punch 1< A9 to form a plurality of through holes 1< R10 in the electrical steel sheet ES (see the position 1< P16 in FIG. 6 and FIG. 11). In the present embodiment, one through hole 1< R10 is positioned between adjacent through holes 1< R7, and these through holes 1< R10 are arranged in a circular shape as a whole. Two through holes 1< R10 are positioned between adjacent worked areas 1< R8, and these through holes 1< R10 are arranged in a circular shape as a whole. The waste material cut out is ejected from the ejection hole 1< C9 of the lower die 132. Each through hole 1< R10 corresponds to the through hole 13b of the connecting tab portion 13 in the blanked member W1 of the stacked stator core 1. When the connecting tab 13a in the connecting tab portion 13 is formed, the blanking of the electrical steel sheet ES by the punch 1< A9 is not performed.

[0076] Next, the electrical steel sheet ES is fed by the feeding device 120, and when a portion of the electrical steel sheet ES to be worked reaches the punch 1< A10 (sixth punch), the controller 140 instructs the press machine 137 so that the press machine 137 elevates or lowers the movable unit 150. The position coincident with the region in the electrical steel sheet ES where the blanked member 1< W2 is cut out is blanked by the punch 1< A10, so that one through hole 1< R11 (center-corresponding hole) having a circular shape is formed in the electrical steel sheet ES (sixth step; sixth process; see the position 1< P18 in FIG. 6, FIG. 11, and FIG. 12). In the present embodiment, the through hole 1< R11 is blanked by the punch 1< A10 at the position coincident with the through hole 1< R6 and has an outer shape larger than that of the through hole 1< R6. The through hole 1< R11 overlaps a part of each through hole 1< R7 on the center side of the through hole 1< R6. The through hole 1< R11 is thus communicatively connected with each through hole 1< R7. The waste material cut out is ejected from the ejection hole 1< C10 of the lower die 132. The through hole 1< R11 corresponds to the through hole W1a in the blanked member W1 of the stacked stator core 1. In blanking the electrical steel sheet ES by the punch 1< A10, the pilot pins 1< B8 and 1< B9 (third pilot pin) are inserted into the through holes 1< R9a whereby the electrical steel sheet ES is positioned (see the positions 1< P17 and 1< P19 in FIG. 6 and FIG. 12).

[0077] Next, the electrical steel sheet ES is fed by the feeding device 120, and when a portion of the electrical steel sheet ES to be worked reaches the punch 1< A11, the controller 140 instructs the press machine 137 so that the press machine 137 elevates or lowers the movable unit 150. The electrical steel sheet ES is thus processed by the punch 1< A11 to form a plurality of worked areas 1< R12 in the electrical steel sheet ES (see the position 1< P20 in FIG. 6 and FIG. 12). In the present embodiment, one worked area 1< R12 is positioned between adjacent through holes 1< R7, and these worked areas 1< R12 are arranged in a circular shape as a whole. Two worked areas 1< R12 are positioned between adjacent worked areas 1< R8, and these worked areas 1< R12 are arranged in a circular shape as a whole. Each worked area 1< R12 corresponds to the connecting tab 13a of the connecting tab portion 13 in the blanked member W1 of the stacked stator core 1. In blanking the electrical steel sheet ES by the punch 1< A11, the pilot pins 1< B9 and 1< B10 are inserted into the through holes 1< R9a whereby the electrical steel sheet ES is positioned (see the positions 1< P19 and 1< P21 in FIG. 6 and FIG. 12).

[0078] When the through holes 1< R10 have already been formed in the electrical steel sheet ES at the position 1< P16, the punch 1< A11 passes through the through holes 1< R10 and misses the electrical steel sheet ES, so that the worked areas 1< R12 are not formed in the electrical steel sheet ES. That is, either of the through holes 1< R10 or the worked areas 1< R12 are selectively formed in the electrical steel sheet ES.

[0079] Next, the electrical steel sheet ES is fed by the feeding device 120, and when a portion of the electrical steel sheet ES to be worked reaches the punch 1< A12 (fourth punch), the controller 140 instructs the press machine 137 so that the press machine 137 elevates or lowers the movable unit 150. The region including worked areas 1< R8 of the electrical steel sheet ES is thus blanked by the punch 1< A12, and the blanked member 1< W1 is stacked on the cylinder 132b in the ejection hole 1< C12 (fourth step; fourth process; see the position 1< P23 in FIG. 6 and FIG. 12). The above steps / processes are repeated whereby a plurality of blanked members 1< W1 are stacked on the cylinder 132b while being joined by the connecting tab portions 13 to form the stacked stator core 1. In blanking the electrical steel sheet ES by the punch 1< A12, the pilot pins 1< B11 and 1< B13 (second pilot pin) are inserted into the through holes 1< R9a whereby the electrical steel sheet ES is positioned (see the positions 1< P22 and 1< P25 in FIG. 6 and FIG. 12). In blanking the electrical steel sheet ES by the punch 1< A12, as illustrated in FIG. 8, the pilot pin 1< B12 (second pilot pin) passes through the through hole 2< R9b (described later), and the tip end of the pilot pin 1< B12 is inserted into the pilot hole 1< E12 to restrain the die holder 133a holding the die 1< D12 from rotating (see the position 1< P24 in FIG. 6 and FIG. 12).

[0080] On the other hand, in the second line L2, through holes 2< R1a, 2< R1b, 2< R2 to 2< R4, 2< R6, 2< R7, 2< R9a, 2< R9b, 2< R10, and 2< R11, and worked areas 2< R5, 2< R8, and 2< R12 are formed in the electrical steel sheet ES in the same manner as described above in connection with the first line L1, and the blanked members 2< W1 and 2< W2 are formed through the process (see FIG. 7 and FIG. 10 to FIG. 12). A detailed description of the stacked stator core 1 and the stacked rotor core 2 in the second line L2 is omitted below.[Effects]

[0081] In the present embodiment as described above, the electrical steel sheet ES is processed by the punch 1< A7 so that the worked areas 1< R8 are each formed between the through holes 1< R2 and 1< R6 in the electrical steel sheet ES. Since the electrical steel sheet ES undergoes lancing or blanking and pushing-back during the process of forming the worked areas 1< R8, the worked areas 1< R8 are press-fitted into the position to be worked while expanding themselves outward in the plane of the electrical steel sheet ES. Although the worked areas 1< R8 are firmly fitted in the electrical steel sheet ES to an extent that is not easily disengaged manually, strain may be generated in the electrical steel sheet ES. However, in the present embodiment, another through hole 1< R9a different from the through hole 1< R1a is formed in the electrical steel sheet ES after the worked areas 1< R8 are formed and before the electrical steel sheet ES undergoes another process. That is, the through hole 1< R9a is formed in the electrical steel sheet ES deformed by strain. The position of the through hole 1< R9a therefore is not displaced or the amount of displacement of the through hole 1< R9a is very small. Accordingly, in a subsequent step, the pilot pins 1< B8 to 1< B11 and 1< B13 can be inserted into the through holes 1< R9a to position the electrical steel sheet ES, so that the blanked member 1< W1 formed by blanking the electrical steel sheet ES with the punch 1< A12 can achieve the shape as designed. As a result, the stacked stator core 1 can be formed accurately even through lancing or blanking and pushing-back of the electrical steel sheet ES.

[0082] In the present embodiment, the through hole 1< R9a is blanked by the punch 1< A8 at the position coincident with the through hole 1< R1a and has an outer shape larger than that of the through hole 1< R1a. That is, the through hole 1< R9a is formed so as to overlap the through hole 1< R1a. This eliminates the need for separately reserving a region for forming the through hole 1< R9a in the electrical steel sheet ES. A narrower electrical steel sheet ES therefore can be used, thereby improving the yield. As a result, the production cost for the stacked stator core 1 and the stacked rotor core 2 can be reduced. In particular, when the entire length of one coil material 111 fed from the uncoiler 110 is, for example, approximately several hundred meters to several tens of thousands of meters, the narrower electrical steel sheet ES very effectively achieves yield improvement and lower cost.

[0083] In the present embodiment, after the through hole 1< R9a is formed in the electrical steel sheet ES, the through hole 1< R11 is formed in the electrical steel sheet ES in a state in which the pilot pins 1< B8 and 1< B9 are inserted into the through holes 1< R9a to position the electrical steel sheet ES. The through hole 1a of the stacked stator core 1 thus can be formed in a shape as desired. Accordingly, the air gap, which is an important parameter in motors, can be formed very accurately, thereby improving the performance of the motor.

[0084] In the present embodiment, the blanked member 1< W2 for the stacked rotor core 2 is blanked from the electrical steel sheet ES by the punch 1< A5 in a state in which the pilot pin 1< B3 is inserted into the through hole 2< R1b and the tip end of the pilot pin 1< B3 is inserted into the pilot hole 1< E3. That is, when the blanked member 1< W2 is stacked, the pilot pin 1< B3 is engaged in the pilot hole 1< E3 to restrain the die holder 133a holding the die 1< D5 from rotating. Therefore, the blanked members 1< W2 can be stacked appropriately without causing a shift in the rotational stacking angle. In addition, the pilot pin 1< B3 is engaged in the pilot hole 1< E3 while being inserted into the through hole 2< R1b formed in the electrical steel sheet ES. This eliminates the need for disposing the pilot pin 1< B3 so as to avoid the electrical steel sheet ES and can achieve downsizing of the apparatus 100 including the pilot pin 1< B3 and the cylinder 132b as a whole.

[0085] In the present embodiment, the blanked members 1< W1 and 1< W2 and the blanked members 2< W1 and 2< W2 are individually formed in a plurality of rows. In such multiple line arrangement work, lancing or blanking and pushing-back of the electrical steel sheet ES causes even greater amount of strain in the electrical steel sheet ES. The position of the through hole 1< R1a may be significantly displaced accordingly. However, in the present embodiment, as described above, the through hole 1< R9a is formed in the electrical steel sheet ES deformed by strain, and the electrical steel sheet ES undergoes the subsequent work in a state in which the pilot pins 1< B8 to 1< B11 and 1< B13 are inserted into the through holes 1< R9a to position the electrical steel sheet ES. Thus, even in the multiple line arrangement work in which the electrical steel sheet ES is more likely to be deformed, the stacked stator core 1 and the stacked rotor core 2 can be formed accurately.

[0086] Similar operational effects as described above can be achieved also when the stacked stator core 1 and the stacked rotor core 2 are produced in the second line L2.[Other Embodiments]

[0087] Although an embodiment of the present disclosure has been described in detail above, the embodiment is susceptible to various modifications without departing from the spirit of the present invention. For example, the through holes 1< R1a and 1< R1b may be formed in advance in the electrical steel sheet ES by another apparatus different from the apparatus 100.

[0088] In the foregoing embodiment, the through hole 1< R9a is formed in the electrical steel sheet ES such that the through hole 1< R9a overlaps the through hole 1< R1a. However, the through hole 1< R9a may be formed at a position different from the through hole 1< R1a.

[0089] In the foregoing embodiment, a method of manufacturing the stacked stator core 1 and the stacked rotor core 2 from one electrical steel sheet ES has been described. However, only the stacked stator core 1 may be produced from one electrical steel sheet ES, and only the stacked rotor core 2 may be produced from one electrical steel sheet ES.

[0090] In the foregoing embodiment, in producing the stacked rotor core 2, the tip end of the pilot pin 1< B3 is inserted into the pilot hole 1< E3 while the pilot pin 1< B3 is inserted into the through hole 2< R1b. However, the pilot pin may be used to restrain the die holder 133a from rotating, similarly in producing the stacked stator core 1. The pilot pin 1< B3 may be inserted into the pilot hole 1< E3 through the outside of the electrical steel sheet ES and the die plate 133. When rotational stacking is not performed, the die holder 133a may not have the rotating function.

[0091] In the foregoing embodiment, an arrangement comprising two line arrangement to process the electrical steel sheet ES has been described. However, the present invention is applicable to an arrangement comprising three or more lines.Reference Signs List

[0092] 1 ... stacked stator core 1a ... through hole (center hole) 2 ... stacked rotor core 14 ... slot 100 ... manufacturing apparatus 120 ... feeding device (feeder) 130 ... blanking device 133a ... die holder 133b ... drive mechanism 137 ... press machine (driver) 140 ... controller (control unit) 1< A1 ... punch (first punch, seventh punch) 1< A5 ... punch (eighth punch) 1< A6 ... punch (fifth punch) 1< A7 ... punch (second punch) 1< A8 ... punch (third punch) 1< A10 ... punch (sixth punch) 1< A12 ... punch (fourth punch) Ax1, Ax2 ... center axis 1< B2 to 1< B4 ... pilot pin (fourth pilot pin) 1< B6, 1< B7 ... pilot pin (first pilot pin) 1< R8a, 1< R8b ... through hole (second pilot hole) 1< B8, 1< B9 ... pilot pin (third pilot pin) 1< B11 to 1< B13 ... pilot pin (second pilot pin) ES ... electrical steel sheet (metal plate; workpiece plate) 1< R1a ... through hole (first pilot hole) 1< R1b ... through hole 1< R7 ... through hole (slot-corresponding hole) 1< R8 ... worked area (worked portion) 1< R11 ... through hole (center-corresponding hole) W1, 1< W1, 2< W1 ... blanked member (first blanked member) W2, 1< W2, 2< W2 ... blanked member (second blanked member)

Claims

1. A method of manufacturing a stacked core, the method comprising: a first step of forming a first pilot hole (1R1a) in a strip-like metal plate (ES) by a first punch (1A1); a second step, in a state in which a first pilot pin (1B6, 1B7) is inserted into the first pilot hole (1R1a) to position the metal plate (ES), of working a predetermined portion of the metal plate (ES) by a second punch (1A7), and of press-fitting a worked portion (1R8) of the metal plate (ES) that is worked by the second punch (1A7) into the metal plate (ES); a third step of forming a second pilot hole (1R9a, 1R9b) in the metal plate (ES) by a third punch (1A8), after the second step and before another work is performed on the metal plate (ES); and a fourth step of blanking a region including the worked portion (1R8) by a fourth punch (1A12) to form a first blanked member (W1), in a state in which a second pilot pin (1B11 to 1B13) is inserted into the second pilot hole (1R9a, 1R9b) to position the metal plate (ES), after the third step.

2. The method according to claim 1, wherein in the third step, the second pilot hole (1R9a, 1R9b) having an outer shape larger than that of the first pilot hole (1R1a) is formed by the third punch (1A8) at a position in the metal plate (ES) that coincides with the first pilot hole (1R1a).

3. The method according to claim 1 or 2, further comprising: a fifth step of blanking a region in the metal plate (ES) that corresponds to a slot of a stacked stator core (1) by a fifth punch (1A6) to form a slot-corresponding hole in the metal plate (ES), after the first step and before the second step; and a sixth step of blanking a region in the metal plate (ES) that corresponds to a center hole positioned at a center of a stacked stator core and in which a rotor is disposed, by a sixth punch (1A10) to form a center-corresponding hole in the metal plate (ES), in a state in which a third pilot pin (1B8, 1B9) is inserted into the second pilot hole (1R9a, 1R9b) to position the metal plate (ES), after the third step and before the fourth step.

4. The method according to claim 3, further comprising: a seventh step of forming a through hole in the metal plate (ES) by a seventh punch (1A1), before the second step; and an eighth step of blanking a second blanked member (W2) for a stacked rotor core from the metal plate (ES) by an eighth punch (1A5) through a die held by a rotatable die holder (133a), and of stacking the second blanked member (W2) on another second blanked member already blanked from the metal plate (ES), after the seventh step and before the second step, wherein, in the eighth step, when the second blanked member (W2) is stacked on the another second blanked member, a fourth pilot pin (1B2 to 1B4) inserted into the through hole is engaged in an engagement hole in the rotatable die holder (133a) to restrain the rotatable die holder (133a) from rotating.

5. The method according to any one of claims 1 to 4, wherein the first blanked member (W1) is formed in each of multiple lines shifted in pitch in a width direction of the metal plate (ES).

6. An apparatus for manufacturing a stacked core, the apparatus comprising: a feeder (120) configured to sequentially feed a strip-like metal plate (ES) intermittently; first to fourth punches (1A1, 1A7, 1A8, 1A12); first and second pilot pins (1B6, 1B7, 1B11 to 1B13); a drive unit configured to drive the first to fourth punches and the first and second pilot pins; and a control unit (140), wherein, while controlling the feeder (120) and the drive unit to sequentially feed the metal plate (ES) intermittently, the control unit (140) performs: a first process of forming a first pilot hole (1R1a) in the metal plate (ES) by the first punch (1A1); a second process, in a state in which the first pilot pin (1B6, 1B7) is inserted into the first pilot hole (1R1a) to position the metal plate (ES), of working a predetermined portion of the metal plate (ES) by the second punch (1A7), and of press-fitting a worked portion (1R8) of the metal plate (ES) that is worked by the second punch (1A7) into the metal plate (ES); a third process of forming a second pilot hole (1R9a, 1R9b) in the metal plate (ES) by the third punch (1A8), after the second process and before another work is performed on the metal plate (ES); and a fourth process of blanking a region including the worked portion (1R8) by the fourth punch (1A12) to form a first blanked member, in a state in which a second pilot pin (1B11 to 1B13) is inserted into the second pilot hole (1R9a, 1R9b) to position the metal plate (ES), after the third process.

7. The apparatus according to claim 6, wherein the control unit (140) causes the third punch (1A8) to form the second pilot hole (1R9a, 1R9b) having an outer shape larger than that of the first pilot hole (1R1a) at a position in the metal plate (ES) that coincides with the first pilot hole (1R1a), in the third process.

8. The apparatus according to claim 6 or 7, further comprising: a third pilot pin (1B8, 1B9); and fifth and sixth punches (1A6, 1A10), wherein the control unit (140) controls the drive unit to further perform: a fifth process of blanking a region in the metal plate (ES) that corresponds to a slot of a stacked stator core by the fifth punch (1A6) to form a slot-corresponding hole in the metal plate (ES), after the first process and before the second process; and a sixth process of blanking a region in the metal plate (ES) that corresponds to a center hole positioned at a center of a stacked stator core and in which a rotor is disposed, by the sixth punch (1A10) to form a center-corresponding hole in the metal plate (ES), in a state in which the third pilot pin (1B8, 1B9) is inserted into the second pilot hole (1R9a, 1R9b) to position the metal plate (ES), after the third process and before the fourth process.

9. The apparatus according to claim 8, further comprising: seventh and eighth punches (1A1, 1A5); a fourth pilot pin (1B2 to 1B4); and a rotatable die holder (133a) having an engagement hole configured to be engaged with the fourth pilot pin (1B2 to 1B4), wherein the control unit (140) controls the drive unit to further perform: a seventh process of forming a through hole in the metal plate (ES) by the seventh punch before the second process; and an eighth process, in a state in which the fourth pilot pin (1B2 to 1B4) is inserted into the through hole and engaged in the engagement hole to restrain the die holder (133a) from rotating, of blanking a second blanked member (W2) for a stacked rotor core from the metal plate (ES) by the eighth punch through a die held by the rotatable die holder (133a), and of stacking the second blanked member (W2) on another second blanked member already blanked from the metal plate (ES), after the seventh process and before the second process.

10. The apparatus according to any one of claims 6 to 9, wherein the first blanked member is formed in each of multiple lines shifted in pitch in a width direction of the metal plate (ES).