Apparatus for manufacturing laminated iron core

Abstract

A manufacturing apparatus 10 comprises: a lower die 20; an upper die 40 having a contour punching punch 45 for forming an iron core member 5 by punching a strip-shaped metal plate W; a mounting table 30 that is provided so that it can be raised and lowered and on which the formed core members 5 are sequentially placed; a support member 32 that supports the mounting table 30 so that it can be raised and lowered; a lifting motor 36 that lifts and lowers the mounting table 30 through the support member 32; and a control device 90 that controls the upper die 40 and the lifting motor 36. The control device 90 includes a torque control unit 94 that changes the output torque of the lifting motor 36 from a first output torque to a second output torque higher than the first output torque after a lower surface 45B of the contour punching punch 45 passes through a midpoint between a top dead center and a bottom dead center and before the lower surface reaches the bottom dead center.

Description

Laminated iron core manufacturing equipment

[0001] The present invention relates to a manufacturing apparatus for a laminated iron core.

[0002] Laminated cores used in motors and the like are formed by punching a strip-shaped metal plate (e.g., a strip-shaped steel plate) into a predetermined shape to form core members (cores), and then stacking and integrating the formed core members. For example, laminated cores are formed by stacking and integrating the core members by caulking, welding, adhesive, or the like. For example, Patent Document 1 discloses a manufacturing apparatus for manufacturing a laminated core in which a plurality of core members are stacked and bonded together using an adhesive.

[0003] The manufacturing apparatus disclosed in Patent Document 1 includes a receiving table on which the core members are sequentially placed, a lifting motor that raises and lowers the receiving table, and a control device that controls the rotation of the lifting motor. To more effectively stack the laminated core, the torque limit value of the lifting motor is set to "high" when punching the core members, and an upward pressure (back pressure) is applied by the receiving table on which the laminated core members are sequentially stacked. When the core members are not being punched, the torque limit value of the lifting motor is set to "low" to prevent the receiving table from pushing up the core members.

[0004] Japanese Patent No. 5859715

[0005] However, if the timing for setting the output torque of the lifting motor is inappropriate, the following problems may occur. For example, if the torque limit value is set to "high" too early, the core material may be pushed up by the support base. Also, if the torque limit value is set to "high" too late, sufficient back pressure may not be applied, and punching and stacking of the core material may not be performed properly.

[0006] The present invention has been made in consideration of these points, and its purpose is to provide a laminated core manufacturing device that can apply appropriate back pressure when punching a metal plate to form an iron core member, and can suppress the iron core member placed on a mounting table from being pushed up.

[0007] The laminated core manufacturing apparatus according to the present invention is an apparatus for manufacturing a laminated core in which a plurality of core members are stacked and bonded to one another, and includes a lower mold having a die with a die hole formed therein, an upper mold having a punch corresponding to the die hole and punching a strip-shaped metal plate to form the core member, a mounting table that is provided so as to be able to rise and fall and on which the formed core members are successively placed, a support member that supports the mounting table so as to be able to rise and fall, an elevator motor that raises and lowers the mounting table via the support member, and a scuffer that is provided below the die and applies lateral pressure to the core members placed on the mounting table. and a control device for controlling the upper die and the lifting motor, the control device having a torque control section that changes the output torque of the lifting motor from a first output torque to a second output torque higher than the first output torque, during the period from when the lower surface of the punch passes the midpoint between top dead center and bottom dead center to when the lower surface of the punch reaches the bottom dead center, and the torque control section changes the output torque of the lifting motor from the first output torque to the second output torque during the period from when the lower surface of the punch passes the midpoint to before it comes into contact with the upper surface of the metal plate.

[0008] In the laminated core manufacturing device according to the present invention, the torque control unit changes the output torque of the lifting motor from the first output torque to the second output torque after the bottom surface of the punch passes the midpoint and before it comes into contact with the top surface of the metal plate. According to the above aspect, the timing of the punch's descent and the timing of the application of the second output torque can be synchronized, preventing the core material placed on the mounting table from jumping out of the squeeze ring and ensuring the product precision of the core material. Furthermore, when punching the metal plate, the metal plate is sandwiched between the downward load from the punch and the upward back pressure from the mounting table, thereby preventing the metal plate from flapping and further improving the product precision of the core material.

[0009] Another laminated core manufacturing apparatus according to the present invention is an apparatus for manufacturing a laminated core in which a plurality of core members are stacked and bonded to one another, and includes a lower mold having a die with a die hole formed therein, an upper mold having a punch corresponding to the die hole and punching out a strip-shaped metal plate to form the core member, a mounting table that is provided so as to be able to rise and fall and on which the formed core members are successively placed, support members that support the mounting table so as to be able to rise and fall, an elevator motor that raises and lowers the mounting table via the support members, and a squeeze ring that is arranged below the die and applies lateral pressure to the core members placed on the mounting table. and a control device that controls the upper die and the lifting motor, the control device having a torque control unit that changes the output torque of the lifting motor from a first output torque to a second output torque higher than the first output torque, during the period from when the lower surface of the punch passes the midpoint between top dead center and bottom dead center to when it reaches bottom dead center, and the torque control unit changes the output torque of the lifting motor from the first output torque to the second output torque during the period from when the iron core member formed by punching out the metal plate begins to fall downward to when the lower surface of the punch reaches bottom dead center.

[0010] According to another laminated core manufacturing device of the present invention, the torque control unit changes the output torque of the lifting motor from the first output torque to the second output torque between the time when the core member formed by punching the metal plate starts to fall downward and the time when the lower surface of the punch reaches the bottom dead center. According to this aspect, the timing of the punch's descent and the timing of applying the second output torque can be synchronized, preventing the core member placed on the mounting table from jumping out of the squeeze ring and ensuring the product precision of the core member. Furthermore, because the output torque is changed to the second output torque after the metal plate is punched, back pressure can be applied from the mounting table to the core member while it is inside the squeeze ring, improving lamination precision.

[0011] Another laminated iron core manufacturing apparatus according to the present invention is an apparatus for manufacturing a laminated iron core in which a plurality of iron core members are stacked and bonded to each other, and comprises: a lower mold having a die with a die hole formed therein; an upper mold having a punch corresponding to the die hole and punching a strip-shaped metal plate to form the iron core member; a mounting table that is movable up and down and on which the formed iron core members are sequentially placed; a support member that supports the mounting table so that it can be moved up and down; a lifting motor that raises and lowers the mounting table via the support member; and a control device that controls the upper mold and the lifting motor, and the control device comprises a torque control unit that changes the output torque of the lifting motor from a second output torque higher than the first output torque to the first output torque while the lower surface of the punch moves from bottom dead center to the midpoint between the bottom dead center and top dead center.

[0012] In another laminated core manufacturing device according to the present invention, the torque control unit changes the output torque of the lifting motor from the second output torque to the first output torque during the time it takes for the lower surface of the punch to move from the bottom dead center to the midpoint. According to the above aspect, the torque control unit changes the output torque to the first output torque during the short time it takes for the lower surface of the punch to move from the bottom dead center to the midpoint, thereby applying an appropriate back pressure when punching out the metal plate to form the core member, while suppressing the occurrence of thrust-up of the core member placed on the mounting table.

[0013] According to the present invention, it is possible to provide a laminated core manufacturing device that can apply an appropriate back pressure when punching a metal plate to form an iron core member and can suppress the iron core member placed on a mounting table from being pushed up.

[0014] Fig. 1 is a cross-sectional view showing a part of a laminated iron core manufacturing apparatus according to one embodiment. Fig. 2 is an example of a graph showing the relationship between the vertical position of an upper die, the position of a mounting table, and the output torque of an elevator motor according to one embodiment.

[0015] Hereinafter, an embodiment of a laminated iron core manufacturing apparatus according to the present invention will be described with reference to the drawings. It should be noted that the embodiment described here is not intended to limit the present invention in any particular way. Furthermore, the same reference numerals are used for components and parts that perform the same functions, and redundant descriptions will be omitted or simplified as appropriate.

[0016] As shown in Figure 1, a laminated core manufacturing apparatus 10 (hereinafter referred to as manufacturing apparatus 10) of this embodiment manufactures a laminated core 8 in which a plurality of core members 5 are stacked and bonded to one another. The manufacturing apparatus 10 is a progressive press die. In the manufacturing apparatus 10, a strip-shaped metal sheet W is intermittently conveyed in a progressive feed direction D. The strip-shaped metal sheet W is, for example, a coil material (strip-shaped thin steel sheet). The manufacturing apparatus 10 includes a lower die 20, an upper die 40, a pilot pin 50, a stripper plate 60, and a control device 90.

[0017] The lower mold 20 is fixed to the floor surface. As shown in Fig. 1, the lower mold 20 is provided with an outline punching stage 25. The outline punching stage 25 includes a die plate 22, a die 23, an outline punching die hole 26, a squeeze ring 27, and an outline punching punch 45, which will be described later. The outline punching die hole 26 is an example of a die hole. The outline punching punch 45 is an example of a punch.

[0018] The lower mold 20 has a lower mold body 21, a die plate 22, and a die 23. The die plate 22 and the die 23 are placed on the lower mold body 21. The die plate 22 holds the die 23. The die 23 includes an outer shape punching stage 25. A die hole 26 for punching the outer shape is formed in the die 23. An upper surface 22T of the die plate 22 and an upper surface 23T of the die 23 are located at the same height.

[0019] As shown in Fig. 1, the squeeze ring 27 is disposed below the die 23. The squeeze ring 27 holds the formed core material 5 from the side. The squeeze ring 27 applies lateral pressure (i.e., clamping force) to the stacked core materials 5. The squeeze ring 27 holds the core material 5, which has been punched into the outline punching die hole 26 by an outline punching punch 45 (described later), with a predetermined lateral pressure.

[0020] The strip-shaped metal sheet W is intermittently transported to the lower die 20 by a transport device (not shown) provided near the manufacturing apparatus 10. The strip-shaped metal sheet W is intermittently transported to the outline punching stage 25. The transport device holds the strip-shaped metal sheet W in a wound state. The strip-shaped metal sheet W is transported to the lower die 20 by an unwinding device (not shown) of the transport device, and scrap material of the pressed strip-shaped metal sheet W is transported from the lower die 20 by a winding device (not shown) of the transport device and wound onto the winding device. Note that instead of the unwinding device and winding device of the transport device, the strip-shaped metal sheet W may be sandwiched between a pair of upper and lower rotating rolls arranged respectively upstream and downstream of the manufacturing apparatus 10 and transported.

[0021] As shown in FIG. 1 , the manufacturing apparatus 10 includes a mounting table 30, a support member 32, and an elevation motor 36. The mounting table 30 is configured to be able to move up and down. The formed core members 5 are sequentially placed on the mounting table 30. The mounting table 30 has a mounting surface 30F on which the core members 5 are placed. The mounting surface 30F can be located inside the die 23 and the squeeze ring 27. The laminated core 8 is manufactured on the mounting surface 30F.

[0022] As shown in FIG. 1 , the support member 32 supports the mounting table 30 so that it can be raised and lowered. The support member 32 includes a support shaft 33 and a ball screw 35. The support shaft 33 extends in the vertical direction Z. The upper end of the support shaft 33 is connected to the lower end of the mounting table 30. The support shaft 33 supports the mounting table 30. The lower end of the support shaft 33 is connected to a nut 35A (described later) of the ball screw 35. The ball screw 35 includes a nut 35A and a screw shaft 35B. The nut 35A is threadedly engaged with the screw shaft 35B. The screw shaft 35B is connected to the rotation shaft of the lift motor 36. When the lift motor 36 rotates, the screw shaft 35B rotates, causing the nut 35A to rise and fall. This causes the mounting table 30 to rise and fall as well.

[0023] As shown in FIG. 1 , the lift motor 36 raises and lowers the mounting table 30 via the support member 32. Examples of the lift motor 36 include a servo motor and a stepping motor. The lift motor 36 is controlled by a control device 90. The lift motor 36 is configured to press upward the core material 5 placed on the mounting surface 30F via the support member 32 and the mounting table 30. This applies back pressure to the core material 5. As will be described later, the core material 5 placed on the mounting table 30 can be applied with two back pressures: one caused by setting the output torque of the lift motor 36 to a first output torque and the other caused by setting the output torque of the lift motor 36 to a second output torque. Note that the back pressure applied to the core material 5 by setting the output torque to the first output torque is smaller than the lateral pressure applied to the core material 5 by the squeeze ring 27. This prevents the core material 5 from being pushed up.

[0024] 1, the manufacturing apparatus 10 includes a sensor 38 that detects a load applied to the mounting table 30 from the outer shape punching punch 45 when the metal plate W is punched to form the iron core member 5. The sensor 38 is provided on the mounting table 30. The sensor 38 is connected to a control device 90. The sensor 38 is, for example, a pressure sensor. Note that the sensor 38 directly detects the load applied to the mounting table 30 from the outer shape punching punch 45, but the sensor may also detect the load indirectly by another method.

[0025] As shown in FIG. 1 , the upper die 40 is disposed above the lower die 20. The upper die 40 is configured to be able to rise and fall (to be able to move in the vertical direction Z). The upper die 40 is configured to be able to move toward and away from the lower die 20. The upper die 40 has an outer shape punching punch 45 that corresponds to the outer shape punching die hole 26. The upper die 40 and the outer shape punching punch 45 rise and fall together. The outer shape punching punch 45 is located above the outer shape punching die hole 26. The outer shape punching punch 45 is configured to be able to pass through the outer shape punching die hole 26. After the upper die 40 descends and approaches the lower die 20 in the outer shape punching stage 25, the strip-shaped metal plate W is punched out by the outer shape punching punch 45 and the outer shape punching die hole 26. As a result, the outer shape of the core member 5 is formed on the strip-shaped metal plate W, completing the core member 5, which is then stacked one after another on the mounting table 30. When the strip-shaped metal plate W is punched out, the output torque of the lifting motor 36 is changed to a second output torque, as will be described later, and back pressure is applied to the core member 5. Here, the stacked core members 5 are joined to each other by crimping. For example, the laminated core 8 is formed by repeatedly joining the crimped portions (joint portions) formed on each of two core members 5 stacked in the vertical direction Z to each other by crimping.

[0026] As shown in FIG. 1 , the pilot pin 50 is provided on the upper die 40. The pilot pin 50 is configured to be movable in the up-down direction Z together with the upper die 40. The pilot pin 50 is configured to be insertable into a pilot hole PH formed in the metal sheet W. When the upper die 40 is lowered, the pilot pin 50 is inserted into the pilot hole PH. When the pilot pin 50 is inserted into the pilot hole PH, the band-shaped metal sheet W is positioned relative to the manufacturing apparatus 10 (e.g., the mounting table 30).

[0027] As shown in FIG. 1 , the stripper plate 60 is provided on the upper mold 40. The stripper plate 60 is positioned opposite the die plate 22 of the lower mold 20. The stripper plate 60 is configured to be movable in the vertical direction Z together with the upper mold 40. The stripper plate 60 is configured to be movable downward to a lowest position (not shown), which is the lowest position. The stripper plate 60 restricts movement of the metal sheet W in the vertical direction Z at the lowest position when the strip-shaped metal sheet W is punched out by the outline punch 45. When the stripper plate 60 moves to the lowest position, it is configured to press the intermittently conveyed strip-shaped metal sheet W against the lower mold 20 (here, the die plate 22 and the die 23) and sandwich the strip-shaped metal sheet W together with the lower mold 20 (here, the die plate 22 and the die 23). The stripper plate 60 presses the strip-shaped metal sheet W against the upper surface 22T of the die plate 22 and the upper surface 23T of the die 23. A punch insertion hole 60A through which the outline punching punch 45 is inserted is formed in the stripper plate 60. When the upper die 40 is lowered and the stripper plate 60 presses the band-shaped metal sheet W against the die plate 22, the upper die 40 is further lowered, causing the outline punching punch 45 to protrude from the punch insertion hole 60A and be inserted into the outline punching die hole 26.

[0028] 2 is an example of a graph showing the relationship between the vertical Z position of the upper mold 40, the vertical Z position of the mounting table 30, and the output torque of the lifting motor 36 during one cycle from when the upper mold 40, located at the top dead center, passes through the bottom dead center and returns to the top dead center. The relationships between the vertical Z position of the upper mold 40, the vertical Z position of the mounting table 30, and the output torque of the lifting motor 36 are not limited to those shown in FIG. 2. The vertical axis of FIG. 2 indicates the vertical Z position of the upper mold 40 and the vertical Z position of the mounting table 30, and the horizontal axis of FIG. 2 indicates the angle (crank angle) of the upper mold 40. In FIG. 1, the vertical Z position of the upper mold 40 is indicated by a solid line, the output torque of the lifting motor 36 is indicated by a dashed line, and the vertical Z position of the mounting table 30 is indicated by a dashed line.

[0029] As shown in FIG. 2 , at time T0 when the upper die 40 is at the top dead center, the strip-shaped metal sheet W is being transported in the forward feed direction D (see FIG. 1 ). At this time, the output torque of the lifting motor 36 is set to a first output torque by a torque control unit 94 (described later). The upper die 40 moves downward and passes the midpoint between the top dead center and the bottom dead center at time T1. When the upper die 40 reaches time T2, the transport of the strip-shaped metal sheet W is completed. That is, the transport of the strip-shaped metal sheet W is stopped from time T2 to time T12 (described later). When the upper die 40 moves further downward and reaches time T3, the pilot pin 50 begins to be inserted into the pilot hole PH formed in the metal sheet W. That is, the pilot pin 50 is not inserted into the pilot hole PH before time T3. When the upper die 40 moves further downward and reaches time T4, the stripper plate 60 comes into contact with the metal sheet W. When the upper die 40 moves further downward and reaches timing T5, the punch 45 begins punching out the metal sheet W. That is, the lower surface 45B of the punch 45 comes into contact with the upper surface WT (see FIG. 1 ) of the metal sheet W. In the example shown in FIG. 2 , the output torque of the lifting motor 36 is changed from the first output torque to the second output torque by the torque control unit 94 at a timing prior to timing T5. When the upper die 40 moves further downward and reaches timing T6, the core member 5 formed by punching out the metal sheet W begins to fall downward. Then, at timing T7, the punched and fallen core member 5 abuts against the upper surface 5T of the core member 5 placed on the mounting table 30. When the upper die 40 moves further downward and reaches timing T8, the punch 45 crimps the formed core member 5 and the stacked core members 5 together, thereby joining them to each other. 2, at timing T8, the output torque of the lifting motor 36 is changed from the second output torque to the first output torque by the torque control unit 94.Here, the torque control unit 94 maintains the output torque of the lift motor 36 at the second output torque from timing T5 to timing T8, and maintains the output torque of the lift motor 36 at the first output torque from timing T8 through timing T0 to timing T5. Then, the upper die 40 begins to move upward. When the upper die 40 moves upward from the bottom dead center and reaches timing T9, the outline punching punch 45 exits the punched hole WH (see FIG. 1) formed by punching the metal sheet W. That is, the outline punching punch 45 remains penetrated through the punched hole WH between timings T5 and T9 in FIG. 2. When the upper die 40 moves further upward and reaches timing T10, the stripper plate 60 completes pressing down on the metal sheet W. When the upper die 40 moves further upward and reaches timing T11, the pilot pin 50 inserted in the pilot hole PH is completely removed from the pilot hole PH. Between timing T3 and timing T11, at least a portion of the pilot pin 50 is inserted into the pilot hole PH. When the upper die 40 moves further upward and reaches timing T12, transport of the strip-shaped metal sheet W begins. That is, from timing T12 through timing T0 to timing T2, the strip-shaped metal sheet W is transported in the forward feed direction D. The upper die 40 then moves upward, passing the midpoint at timing T13 and reaching the top dead center at timing T0. In this manner, the upper die 40 repeatedly descends and ascends (i.e., the outer shape punching punch 45 repeatedly descends and ascends), thereby manufacturing a laminated core 8 having a predetermined thickness. After the laminated core 8 is manufactured, the lifting motor 36 is driven to lower the mounting table 30, and the laminated core 8 is then ejected from the manufacturing apparatus 10 by a pusher (not shown). When the upper die 40 is positioned at the top dead point, the lower surface 45B of the punch 45 for punching the outer shape is positioned at the top dead point; when the upper die 40 is positioned at the midpoint, the lower surface 45B of the punch 45 for punching the outer shape is positioned at the midpoint; and when the upper die 40 is positioned at the bottom dead point, the lower surface 45B of the punch 45 for punching the outer shape is positioned at the bottom dead point.

[0030] As shown in FIG. 1 , the control device 90 controls the upper mold 40 and the lifting motor 36. The control device 90 includes, for example, a central processing unit (CPU) that executes instructions from a control program, a ROM that stores the program executed by the CPU, a RAM used as a working area for expanding the program, and a storage device such as a memory that stores the program and various data. The control device 90 includes an upper mold control unit 92 and a torque control unit 94. The functions of each unit of the control device 90 are realized by a program. This program is downloaded, for example, via the Internet. The program may also be read from a recording medium such as a CD or DVD. The functions of each unit of the control device 90 may also be realized by a processor and / or circuit.

[0031] The upper die control unit 92 controls the lifting and lowering movement (movement in the vertical direction Z) of the upper die 40. In this embodiment, the upper die control unit 92 controls the lifting and lowering movement (ascending and descending) of the outline punching punch 45 and the stripper plate 60 in the vertical direction Z by moving the upper die 40 in the vertical direction Z. The upper die control unit 92 controls the approaching and separating of the upper die 40 to the lower die 20 and from the lower die 20. The upper die control unit 92 controls the lifting and descending movement of the outline punching punch 45 so that the outline punching punch 45 remains penetrated through the punched hole WH formed by punching the metal sheet W with the outline punching punch 45 during the period from when the outline punching punch 45 punches out the metal sheet W until the output torque of the elevation motor 36 is changed from the second output torque to the first output torque (for example, from timing T6 to timing T8 or from timing T6 to timing T9 in FIG. 2 ). The upper mold control unit 92 controls the vertical movement of the stripper plate 60 so as to restrict the movement of the metal plate W in the vertical direction Z during at least a portion of the period (for example, timing T6 to timing T9 in Figure 2) during which the contour punching punch 45 remains penetrated through the punching hole WH formed by punching the metal plate W with the contour punching punch 45.

[0032] The torque control unit 94 controls the lift motor 36. By controlling the lift motor 36, the torque control unit 94 controls the lift movement (movement in the up-down direction Z) of the mounting table 30. The torque control unit 94 controls the output torque of the lift motor 36. The torque control unit 94 is configured to be able to change the output torque of the lift motor 36. By changing the output torque, the back pressure applied to the iron core material 5 is changed. The torque control unit 94 sets the output torque of the lift motor 36 to a first output torque so as to suppress the iron core material 5 from being pushed up by the mounting table 30 when the metal plate W is not being punched out by the outer shape punching punch 45. The torque control unit 94 sets the output torque of the lift motor 36 to a second output torque higher than the first output torque so as to apply back pressure to the iron core material 5 by the mounting table 30 when the metal plate W is punched out by the outer shape punching punch 45 to form the iron core material 5. The first output torque and the second output torque are output torques of the lifting motor 36 during the punching process (the process of punching the metal plate W to form the iron core member 5, for example, when the upper die 40 is moving up and down). In other words, the output torque of the lifting motor 36 when the laminated iron core 8 formed on the mounting table 30 is carried out of the manufacturing apparatus 10 or when the mounting table 30 is moved to its initial position is not included in the first output torque and the second output torque.

[0033] The torque control unit 94 may be configured to be able to change the first output torque. The torque control unit 94 may be configured to be able to keep the first output torque constant. That is, the torque control unit 94 may be configured to be unable to change the first output torque. The torque control unit 94 may be configured to be able to change the second output torque. For example, the amount of change in the second output torque is greater than the amount of change in the first output torque. The torque control unit 94 may be configured to be able to change the difference between the first output torque and the second output torque.

[0034] The torque control unit 94 may be configured to be able to change the first output torque in accordance with the load applied to the mounting table 30 from the outline punching punch 45 when punching the metal plate W to form the iron core member 5. The torque control unit 94 may be configured to lower the first output torque as the load applied to the mounting table 30 from the outline punching punch 45 when punching the metal plate W to form the iron core member 5 becomes smaller.

[0035] The torque control unit 94 may be configured to be able to change the first output torque in accordance with the thickness of the iron core member 5. The torque control unit 94 may be configured to reduce the first output torque as the thickness of the iron core member 5 becomes thinner.

[0036] The torque control unit 94 may be configured to be able to change the first output torque in accordance with the outer diameter of the iron core member 5. The torque control unit 94 may be configured to reduce the first output torque as the outer diameter of the iron core member 5 decreases.

[0037] The torque control unit 94 may be configured to be able to change the first output torque depending on the number of crimped portions when crimping one iron core member 5. Crimping one iron core member 5 means stacking and crimping an iron core member 5 formed by punching a metal plate W on top of an iron core member 5 already placed on the mounting table 30. The torque control unit 94 may be configured to lower the first output torque as the number of crimped portions decreases.

[0038] The torque control unit 94 may be configured to be able to change the first output torque in accordance with the lateral pressure applied to the iron core member 5 by the squeeze ring 27. The torque control unit 94 may be configured to reduce the first output torque as the lateral pressure decreases.

[0039] The torque control unit 94 may be configured to be able to change the first output torque in accordance with the warpage of the iron core member 5 caused by the lateral pressure applied to the iron core member 5 by the squeeze ring 27. The torque control unit 94 may be configured to reduce the first output torque as the warpage of the iron core member 5 decreases.

[0040] The torque control unit 94 may be configured to be able to change the first output torque in accordance with the shear resistance of the metal sheet W when the metal sheet W is punched out by the outline punching punch 45. The torque control unit 94 may be configured to reduce the first output torque as the shear resistance of the metal sheet W decreases.

[0041] The torque control unit 94 may be configured to be able to change the first output torque in accordance with the weight per iron core member 5. The torque control unit 94 may be configured to lower the first output torque as the weight per iron core member 5 becomes lighter.

[0042] The torque control unit 94 may be configured to be able to change the second output torque in accordance with the load applied to the mounting table 30 from the outline punching punch 45 when punching the metal plate W to form the iron core member 5. The torque control unit 94 may be configured to increase the second output torque as the load applied to the mounting table 30 from the outline punching punch 45 when punching the metal plate W to form the iron core member 5 increases.

[0043] The torque control unit 94 may be configured to change the second output torque based on the load detected by the sensor 38. The torque control unit 94 may be configured to change the second output torque based on the load detected by the outline punching punch 45 before the lower surface 45B of the outline punching punch 45 comes into contact with the upper surface WT of the metal plate W (e.g., before timing T5 in FIG. 2 ). That is, the torque control unit 94 may be configured to change the second output torque of the iron core member 5 to be formed later based on the load used when the iron core member 5 was previously formed before punching the metal plate W to form the iron core member 5. The torque control unit 94 may be configured to change the second output torque based on the load detected by the sensor 38 while the metal plate W is being punched out by the outline punching punch 45 (e.g., between timings T5 and T6 in FIG. 2 ). That is, the torque control unit 94 may be configured to change the second output torque of the iron core member 5 to be formed later based on the load used when the iron core member 5 was previously formed while punching the metal plate W.

[0044] The torque control unit 94 may be configured to be able to change the second output torque in accordance with the thickness of the iron core member 5. The torque control unit 94 may be configured to increase the second output torque as the thickness of the iron core member 5 increases.

[0045] The torque control unit 94 may be configured to be able to change the second output torque in accordance with the outer diameter of the iron core member 5. The torque control unit 94 may be configured to increase the second output torque as the outer diameter of the iron core member 5 increases.

[0046] The torque control unit 94 may be configured to be able to change the second output torque according to the number of crimped portions when crimping one iron core member 5. The torque control unit 94 may be configured to increase the second output torque as the number of crimped portions increases.

[0047] The torque control unit 94 may be configured to be able to change the second output torque in accordance with the lateral pressure applied to the iron core member 5 by the squeeze ring 27. The torque control unit 94 may be configured to increase the second output torque as the lateral pressure increases.

[0048] The torque control unit 94 may be configured to be able to change the second output torque in accordance with the warpage of the iron core member 5 caused by the lateral pressure applied to the iron core member 5 by the squeeze ring 27. The torque control unit 94 may be configured to increase the second output torque as the warpage of the iron core member 5 increases.

[0049] The torque control unit 94 may be configured to be able to change the second output torque in accordance with the shear resistance of the metal sheet W when the metal sheet W is punched out by the outline punching punch 45. The torque control unit 94 may be configured to increase the second output torque as the shear resistance of the metal sheet W increases.

[0050] The torque control unit 94 changes the output torque of the lift motor 36 from the first output torque to the second output torque. The torque control unit 94 maintains the output torque of the lift motor 36 at the second output torque for a predetermined time. In the example shown in FIG. 2 , the torque control unit 94 maintains the output torque of the lift motor 36 at the second output torque from timing T5 to timing T8.

[0051] The torque control unit 94 may change the output torque of the lifting motor 36 from the first output torque to the second output torque during the period from when the lower surface 45B of the outer shape punching punch 45 (see FIG. 1) passes the midpoint between the top dead center and the bottom dead center to when it reaches the bottom dead center (e.g., timing T1 to timing T8 in FIG. 2). The torque control unit 94 may change the output torque of the lifting motor 36 from the first output torque to the second output torque during the period from when the lower surface 45B of the outer shape punching punch 45 passes the midpoint to when it contacts the upper surface WB of the metal sheet W (e.g., timing T1 to timing T5 in FIG. 2). The torque control unit 94 may change the output torque of the lifting motor 36 from the first output torque to the second output torque when the lower surface 45B of the outer shape punching punch 45 contacts the upper surface WB of the metal sheet W (e.g., timing T5 in FIG. 2). The torque control unit 94 may change the output torque of the lifting motor 36 from the first output torque to the second output torque during a period from when the lower surface 45B of the outline punching punch 45 passes the midpoint to when it comes into contact with the upper surface WB of the metal sheet W (e.g., after timing T1 and before timing T5 in FIG. 2 , or after timing T4 and before timing T5 in FIG. 2 ). The torque control unit 94 may change the output torque of the lifting motor 36 from the first output torque to the second output torque during a period from when the stripper plate 60 comes into contact with the upper surface WT of the metal sheet W to when the lower surface 45B of the punch 45 reaches the bottom dead center (e.g., from timing T4 to timing T8 in FIG. 2 ). The torque control unit 94 may change the output torque of the lifting motor 36 from the first output torque to the second output torque during the period from when the lower surface 45B of the punch 45 contacts the upper surface WT of the metal plate W until when the iron core member 5 formed by punching out the metal plate W abuts against the upper surface 5T of the iron core member 5 placed on the mounting table 30 (for example, from timing T4 to timing T7 in Figure 2).The torque control unit 94 may change the output torque of the lifting motor 36 from the first output torque to the second output torque during the period from when the iron core member 5 formed by punching out the metal plate W starts to fall downward until the lower surface 45B of the punch 45 reaches the bottom dead center (for example, from timing T6 to timing T8 in FIG. 2). The torque control unit 94 may change the output torque of the lifting motor 36 from the first output torque to the second output torque during the period from when the iron core member 5 formed by punching out the metal plate W starts to fall downward until the formed iron core member 5 comes into contact with the upper surface 5T of the iron core member 5 placed on the placing table 30 (for example, from timing T6 to timing T7 in FIG. 2). The torque control unit 94 may change the output torque of the lift motor 36 from the first output torque to the second output torque during the period from when the core member 5 formed by punching the metal plate W comes into contact with the upper surface 5T of the core member 5 placed on the mounting table 30 until the lower surface 45B of the punch 45 reaches the bottom dead center (for example, from timing T7 to timing T8 in FIG. 2 ). When changing the output torque of the lift motor 36, a signal for changing the output torque is sent from the control device 90 to the lift motor 36. Here, "changing the output torque of the lift motor 36" includes both a case in which the control device 90 sends a signal for changing the output torque to the lift motor 36 before the timing to change the output torque of the lift motor 36, and the change in output torque is completed at the timing to change the output torque of the lift motor 36, and a case in which the control device 90 sends a signal for changing the output torque to the lift motor 36 before the timing to change the output torque of the lift motor 36, and the change in output torque continues at the timing to change the output torque of the lift motor 36.

[0052] The timing at which the torque control unit 94 changes the output torque of the lifting motor 36 from the first output torque to the second output torque may be the same in the nth punching process in which the metal plate W is punched with the outline punching punch 45 to form the nth (n is a natural number) iron core member 5, and the (n+1)th punching process in which the metal plate W is punched with the outline punching punch 45 to form the (n+1)th iron core member 5. For example, the timing at which the output torque is changed may be the same in the first punching process and the second punching process.

[0053] The torque control unit 94 may be configured to change the timing at which the output torque of the lift motor 36 is changed from the first output torque to the second output torque. The torque control unit 94 may be configured to advance the timing at which the output torque of the lift motor 36 is changed from the first output torque to the second output torque as the second output torque becomes higher. The torque control unit 94 may be configured to advance the timing at which the output torque of the lift motor 36 is changed from the first output torque to the second output torque as the difference between the first output torque and the second output torque becomes larger. The torque control unit 94 may be configured to advance the timing at which the output torque of the lift motor 36 is changed from the first output torque to the second output torque as the thickness of the metal plate W becomes thicker.

[0054] The torque control unit 94 changes the output torque of the lift motor 36 from the first output torque to the second output torque in a rectangular wave shape (see FIG. 2). The torque control unit 94 may gradually change the output torque of the lift motor 36 from the first output torque to the second output torque. The torque control unit 94 may also change the output torque of the lift motor 36 from the first output torque to the second output torque in a trapezoidal wave shape, a sine wave shape, a triangular wave shape, or a sawtooth wave shape.

[0055] The torque control unit 94 changes the output torque of the lift motor 36 from the second output torque to the first output torque. The torque control unit 94 maintains the output torque of the lift motor 36 at the first output torque for a predetermined period of time. In the example shown in FIG. 2 , the torque control unit 94 maintains the output torque of the lift motor 36 at the first output torque from time T8 through time T0 to time T5.

[0056] The torque control unit 94 may change the output torque of the lifting motor 36 from the second output torque to the first output torque during the period from the bottom dead center until the lower surface 45B (see FIG. 1) of the outline punching punch 45 reaches the midpoint (for example, timing T8 to timing T13 in FIG. 2). The torque control unit 94 may change the output torque of the lifting motor 36 from the second output torque to the first output torque when the lower surface 45B (see FIG. 1) of the outline punching punch 45 starts to rise from the bottom dead center (for example, timing T8 in FIG. 2).

[0057] The timing at which the torque control unit 94 changes the output torque of the lifting motor 36 from the second output torque to the first output torque may be the same in the nth punching process in which the metal plate W is punched with the outline punching punch 45 to form the nth (n is a natural number) iron core member 5, and the (n+1)th punching process in which the metal plate W is punched with the outline punching punch 45 to form the (n+1)th iron core member 5. For example, the timing at which the output torque is changed may be the same in the first punching process and the second punching process.

[0058] The torque control unit 94 may be configured to change the timing at which the output torque of the lift motor 36 is changed from the second output torque to the first output torque. The torque control unit 94 may be configured to delay the timing at which the change of the output torque of the lift motor 36 from the second output torque to the first output torque is completed as the first output torque becomes lower. The torque control unit 94 may be configured to delay the timing at which the change of the output torque of the lift motor 36 from the second output torque to the first output torque is completed as the difference between the first output torque and the second output torque becomes larger.

[0059] The torque control unit 94 changes the output torque of the lift motor 36 from the second output torque to the first output torque in a rectangular wave shape (see FIG. 2). The torque control unit 94 may gradually change the output torque of the lift motor 36 from the second output torque to the first output torque. The torque control unit 94 may change the output torque of the lift motor 36 from the second output torque to the first output torque in a trapezoidal wave shape, a sine wave shape, a triangular wave shape, or a sawtooth wave shape.

[0060] As described above, in the laminated core manufacturing apparatus 10 of this embodiment, the torque control unit 94 may change the output torque of the lifting motor 36 from the first output torque to the second output torque during the period from when the lower surface 45B of the outline punching punch 45 passes the midpoint to when it reaches the bottom dead center. According to the above aspect, the torque control unit 94 changes the output torque of the lifting motor 36 to the second output torque during the short period from when the lower surface 45B of the outline punching punch 45 passes the midpoint to when it reaches the bottom dead center, thereby suppressing the occurrence of push-up of the iron core material 5 placed on the mounting table 30 and applying an appropriate back pressure when punching the metal plate W to form the iron core material 5.

[0061] In the laminated core manufacturing apparatus 10 of this embodiment, the torque control unit 94 may change the output torque of the lifting motor 36 from the first output torque to the second output torque during the period from when the lower surface 45B of the outline punching punch 45 passes the midpoint until it comes into contact with the upper surface WT of the metal sheet W. According to the above-described aspect, back pressure can be applied at a more appropriate timing when punching the metal sheet W to form the iron core member 5.

[0062] In the laminated core manufacturing apparatus 10 of this embodiment, the torque control unit 94 may change the output torque of the lifting motor 36 from the first output torque to the second output torque when the lower surface 45B of the outline punching punch 45 comes into contact with the upper surface WT of the metal plate W. According to the above aspect, back pressure can be applied at more appropriate timing when punching the metal plate W to form the iron core member 5.

[0063] In the laminated core manufacturing apparatus 10 of this embodiment, the output torque of the lifting motor 36 may be changed from the first output torque to the second output torque after the lower surface 45B of the outline punching punch 45 passes the midpoint and before it comes into contact with the upper surface WB of the metal sheet W. This allows the timing of the descent of the outline punching punch 45 to be synchronized with the timing of applying the second output torque, thereby preventing the core material 5 placed on the mounting table 30 from jumping out of the squeeze ring 27 and ensuring the product precision of the core material 5. Furthermore, when punching out the metal sheet W, the metal sheet W is sandwiched between the downward load from the outline punching punch 45 and the upward back pressure from the mounting table 30, thereby preventing the metal sheet W from flapping and further improving the product precision of the core material 5.

[0064] In the laminated core manufacturing apparatus 10 of this embodiment, the torque control unit 94 may change the output torque of the lifting motor 36 from the first output torque to the second output torque during the period from when the stripper plate 60 contacts the upper surface WT of the metal sheet W until when the lower surface 45B of the punch 45 reaches the bottom dead center. According to the above-described aspect, back pressure can be applied at a more appropriate timing when punching the metal sheet W to form the iron core member 5.

[0065] In the laminated core manufacturing apparatus 10 of this embodiment, the torque control unit 94 may change the output torque of the lifting motor 36 from the first output torque to the second output torque during the period from when the lower surface 45B of the punch 45 contacts the upper surface WT of the metal plate W until the core member 5 formed by punching out the metal plate W abuts against the upper surface 5T of the core member 5 placed on the mounting table 30. According to the above-described aspect, back pressure can be applied at a more appropriate timing when punching out the metal plate W and stacking the core members 5.

[0066] In the laminated core manufacturing apparatus 10 of this embodiment, the torque control unit 94 may change the output torque of the lifting motor 36 from the first output torque to the second output torque during the period from when the iron core member 5 formed by punching the metal sheet W starts to fall downward until the lower surface 45B of the punch 45 reaches the bottom dead center. According to the above-described aspect, back pressure can be applied at a more appropriate timing when the iron core member 5 is formed by punching the metal sheet W.

[0067] In the laminated core manufacturing apparatus 10 of this embodiment, the torque control unit 94 may change the output torque of the lifting motor 36 from the first output torque to the second output torque during the period from when the core member 5 formed by punching out the metal plate W starts to fall downward until when the formed core member 5 abuts against the upper surface 5T of the core member 5 placed on the mounting table 30. According to the above-described aspect, back pressure can be applied at more appropriate timing when punching out the metal plate W and stacking the core members 5.

[0068] In the laminated core manufacturing apparatus 10 of this embodiment, the torque control unit 94 may change the output torque of the lifting motor 36 from the first output torque to the second output torque during the period from when the core member 5 formed by punching the metal sheet W comes into contact with the upper surface 5T of the core member 5 placed on the mounting table 30 until the lower surface 45B of the punch 45 reaches the bottom dead center. According to the above-described aspect, back pressure can be applied at a more appropriate timing when punching the metal sheet W to laminate the core members 5.

[0069] In the laminated core manufacturing apparatus 10 of this embodiment, the torque control unit 94 may change the output torque of the lifting motor 36 from the first output torque to the second output torque in a rectangular wave shape. According to the above aspect, the change to the second output torque is performed instantaneously, so that an appropriate back pressure can be applied while suppressing the thrust of the core material 5.

[0070] In the laminated core manufacturing apparatus 10 of this embodiment, the torque control unit 94 may gradually change the output torque of the lifting motor 36 from the first output torque to the second output torque. According to the above aspect, even if the timing of applying back pressure to the core material 5 is slightly off, it is possible to suppress the core material 5 from being pushed up.

[0071] In the laminated core manufacturing apparatus 10 of this embodiment, the timing at which the torque control unit 94 changes the output torque of the lifting motor 36 from the first output torque to the second output torque may be the same in the first punching process in which the metal plate W is punched with the outline punching punch 45 to form the first core member 5, and in the second punching process in which the metal plate W is punched with the outline punching punch 45 to form the second core member 5. According to the above aspect, the lifting motor 36 is easily controlled.

[0072] In the laminated core manufacturing apparatus 10 of this embodiment, the torque control unit 94 may be configured to be able to change the second output torque. According to the above aspect, the second output torque can be appropriately set depending on the metal sheet W and the core member 5 to be formed, so that an appropriate back pressure can be applied when punching the metal sheet W to form the core member 5.

[0073] In the laminated core manufacturing apparatus 10 of this embodiment, the torque control unit 94 may be configured to increase the second output torque as the load applied to the mounting table 30 from the outline punch 45 when punching the metal plate W to form the iron core member 5 increases. According to the above aspect, an appropriate back pressure can be applied when punching the metal plate W to form the iron core member 5.

[0074] In the laminated core manufacturing apparatus 10 of this embodiment, the torque control unit 94 may be configured to be able to change the timing at which the output torque of the lifting motor 36 is changed from the first output torque to the second output torque. According to the above aspect, the timing at which the output torque is changed can be appropriately set depending on the metal sheet W and the core member 5 to be formed, so that an appropriate back pressure can be applied when punching out the metal sheet W to form the core member 5 while suppressing the occurrence of push-up of the core member 5 placed on the mounting table 30.

[0075] In the laminated core manufacturing apparatus 10 of this embodiment, the torque control unit 94 may be configured to be able to change the second output torque, and may be configured to change the output torque of the lifting motor 36 from the first output torque to the second output torque earlier as the second output torque becomes higher. According to the above aspect, an appropriate back pressure can be applied more quickly when punching the metal sheet W to form the iron core member 5.

[0076] In the laminated core manufacturing apparatus 10 of this embodiment, the torque control unit 94 may be configured to be able to change at least one of the first output torque and the second output torque, and may be configured to accelerate the timing at which the output torque of the lifting motor 36 is changed from the first output torque to the second output torque as the difference between the first output torque and the second output torque increases. According to the above aspect, an appropriate back pressure can be applied more quickly when punching the metal sheet W to form the iron core member 5.

[0077] In the laminated core manufacturing apparatus 10 of this embodiment, the torque control unit 94 may be configured to accelerate the timing at which the output torque of the lifting motor 36 is changed from the first output torque to the second output torque as the thickness of the metal sheet W increases. According to the above aspect, the thicker the metal sheet W, the longer the time for applying back pressure must be. Therefore, by accelerating the timing at which the torque is changed to the second output torque, an appropriate back pressure can be applied when punching the metal sheet W to form the iron core member 5.

[0078] Furthermore, in the laminated core manufacturing apparatus 10 of this embodiment, the torque control unit 94 changes the output torque of the lifting motor 36 from the second output torque to the first output torque during the time it takes for the lower surface 45B of the outline punching punch 45 to move from the bottom dead center to the midpoint. According to the above aspect, the torque control unit 94 changes the output torque of the lifting motor 36 to the first output torque during the short time it takes for the lower surface 45B of the outline punching punch 45 to move from the bottom dead center to the midpoint, thereby applying an appropriate back pressure when punching the metal sheet W to form the iron core member 5 and suppressing the occurrence of thrust-up of the iron core member 5 placed on the mounting table 30.

[0079] In the laminated core manufacturing apparatus 10 of this embodiment, the torque control unit 94 may change the output torque of the lifting motor 36 from the second output torque to the first output torque when the lower surface 45B of the outline punching punch 45 starts to rise from the bottom dead center. According to the above-mentioned aspect, it is possible to more reliably suppress the occurrence of thrust-up of the iron core material 5 placed on the mounting table 30.

[0080] In the laminated core manufacturing apparatus 10 of this embodiment, the torque control unit 94 may change the output torque of the lifting motor 36 from the second output torque to the first output torque in a rectangular wave shape. According to the above aspect, the change to the first output torque is performed instantaneously, so that it is possible to apply an appropriate back pressure while suppressing thrust-up of the core material 5.

[0081] In the laminated core manufacturing apparatus 10 of this embodiment, the torque control unit 94 may gradually change the output torque of the lift motor 36 from the second output torque to the first output torque. According to the above aspect, the operating load of the lift motor 36 can be reduced.

[0082] In the laminated core manufacturing apparatus 10 of this embodiment, the timing at which the torque control unit 94 changes the output torque of the lifting motor 36 from the second output torque to the first output torque is the same in the first punching process in which the metal plate W is punched with the outline punching punch 45 to form the first core member 5, and in the second punching process in which the metal plate W is punched with the outline punching punch 45 to form the second core member 5. According to the above aspect, the lifting motor 36 can be easily controlled.

[0083] In the laminated core manufacturing apparatus 10 of this embodiment, the torque control unit 94 may be configured to be able to change the first output torque. According to the above aspect, the first output torque can be appropriately set, so that thrust-up of the core members 5 can be more reliably suppressed.

[0084] In the laminated core manufacturing apparatus 10 of this embodiment, the torque control unit 94 may be configured to lower the first output torque as the lateral pressure applied to the core members 5 from the squeeze ring 27 becomes smaller. According to the above aspect, the first output torque can be appropriately set, and therefore, thrust-up of the core members 5 can be more reliably suppressed.

[0085] In the laminated core manufacturing apparatus 10 of this embodiment, the torque control unit 94 may be configured to be able to change the timing at which the output torque of the lifting motor 36 is changed from the second output torque to the first output torque. According to the above aspect, the timing at which the output torque is changed can be appropriately set depending on the metal sheet W and the core member 5 to be formed, so that an appropriate back pressure can be applied when punching the metal sheet W to form the core member 5, while preventing the core member 5 placed on the mounting table 30 from being pushed up.

[0086] In the laminated core manufacturing apparatus 10 of this embodiment, the torque control unit 94 may be configured to be able to change the first output torque, and may be configured to delay the timing at which the output torque of the lifting motor 36 is changed from the second output torque to the first output torque as the first output torque decreases. According to the above aspect, an appropriate back pressure can be applied for an appropriate period of time when the metal plate W is punched to form the iron core member 5.

[0087] In the laminated core manufacturing apparatus 10 of this embodiment, the torque control unit 94 may be configured to be able to change at least one of the first output torque and the second output torque, and may be configured to delay the timing at which the output torque of the lifting motor 36 is changed from the second output torque to the first output torque as the difference between the first output torque and the second output torque increases. According to the above aspect, an appropriate back pressure can be applied for an appropriate period of time when the metal plate W is punched to form the iron core member 5.

[0088] In the laminated core manufacturing apparatus 10 of this embodiment, the upper die control unit 92 of the control device 90 may control the lowering and raising of the outer shape punching punch 45 so that the outer shape punching punch 45 remains penetrated through the punched hole WH formed by punching the metal plate W with the outer shape punching punch 45, from the time the outer shape punching punch 45 punches the metal plate W until the output torque of the lifting motor 36 is changed from the second output torque to the first output torque. According to the above aspect, the outer shape punching punch 45 moves in the axial direction of the punched hole WH (i.e., in the vertical direction) based on the punched hole WH formed in the metal plate W that has been positioned with respect to the mounting table 30 by inserting the pilot pin 50 into the pilot hole PH. Therefore, the concentricity of the outer shape punching punch 45 with respect to the axial center of the punched hole WH can be maintained while the output torque is changed from the second output torque to the first output torque.

[0089] In the laminated core manufacturing apparatus 10 of this embodiment, the upper die control unit 92 of the control device 90 may control the vertical movement of the stripper plate 60 so as to restrict movement of the metal plate W in the vertical direction Z during at least a portion of the period during which the outline punching punch 45 maintains a penetrating state through the punching hole WH formed by punching the metal plate W with the outline punching punch 45. According to the above aspect, the outline punching punch 45 moves in the axial direction of the punching hole WH (i.e., in the vertical direction) based on the punching hole WH formed in the metal plate W whose movement in the vertical direction Z is restricted by the stripper plate 60. Therefore, the concentricity of the outline punching punch 45 with respect to the axial center of the punching hole WH can be maintained while the output torque is changed from the second output torque to the first output torque.

[0090] Although the preferred embodiments of the present invention have been described above, the above-described embodiments are merely examples, and the present invention can be embodied in various other forms.

[0091] In the above-described embodiment, the stacked core members 5 are joined to each other by crimping, but the joining method is not limited to crimping. The stacked core members 5 may also be joined to each other by, for example, welding or adhesive. When the stacked core members 5 are joined to each other by adhesive, the torque control unit 94 may be configured to change the first output torque depending on the number of bonding locations when bonding one core member 5. Bonding one core member 5 means stacking and bonding an iron core member 5 formed by punching a metal plate W on an iron core member 5 already placed on the mounting table 30. The torque control unit 94 may be configured to decrease the first output torque as the number of bonding locations decreases. Furthermore, the torque control unit 94 may be configured to change the second output torque depending on the number of bonding locations when bonding one core member 5. The torque control unit 94 may be configured to increase the second output torque as the number of bonding locations increases.

[0092] When the stacked iron core members 5 are bonded to each other by adhesion, the manufacturing apparatus 10 may include an adhesive applicator that applies adhesive to the underside WL (see FIG. 1 ) of the metal plate W. In this case, the control device 90 includes an application control unit that controls the adhesive applicator. The application control unit may control the adhesive applicator to apply adhesive to the underside WL of the metal plate W during at least a portion of the period in which the torque control unit 94 sets the output torque of the lifting motor 36 to the second output torque.

[0093] In the above-described embodiment, the lower mold body 21, the die plate 22, and the die 23 of the lower mold 20 are configured as separate bodies, but they may be configured as an integral body as appropriate. For example, the die plate 22 and the die 23 may be configured as an integral body, or the die plate 22, the die 23, and the lower mold body 21 may be configured as an integral body.

[0094] In the above-described embodiment, the upper surface 23T of the die 23 and the upper surface 22T of the die plate 22 are located at the same height, but this is not limiting. For example, the upper surface 23T of the die 23 may be located lower than the upper surface 22T of the die plate 22. In this case, the stripper plate 60 presses the belt-shaped metal sheet W against the upper surface 22T of the die plate 22.

[0095] In the above-described embodiment, the manufacturing apparatus 10 was equipped with an outer shape punch 45 and an outer shape punching die hole 26, but it may also be equipped with an inner shape punch and an inner shape punching die hole, a pilot hole forming punch and a pilot hole forming die hole, etc.

[0096] The first output torque or the second output torque may be changed as claimed in the claims in a series of manufacturing steps from the start of punching the first core member 5 to the discharge of the laminated core 8 to the outside of the manufacturing apparatus 10. Furthermore, the first output torque or the second output torque may be changed as claimed in the claims in different manufacturing steps.

[0097] 5 Iron core member 8 Laminated iron core 10 Manufacturing device (laminated iron core manufacturing device) 20 Lower die 23 Die 26 Die hole for punching outer shape (die hole) 30 Placement table 32 Support member 36 Lifting motor 40 Upper die 45 Punch for punching outer shape (punch) 90 Control device 94 Torque control section

Claims

1. An apparatus for manufacturing a laminated core in which a plurality of core members are stacked and bonded to one another, comprising: a lower die having a die with a die hole formed therein; an upper die having a punch corresponding to the die hole and punching a strip-shaped metal plate to form the core member; a mounting table that is arranged to be able to rise and fall and on which the formed core members are successively placed; a support member that supports the mounting table so that it can be raised and lowered; a lifting motor that raises and lowers the mounting table via the support member; a squeeze ring that is arranged below the die and applies lateral pressure to the core members placed on the mounting table; and a control device that controls the upper die and the lifting motor, wherein the control device has a torque control unit that changes the output torque of the lifting motor from a first output torque to a second output torque higher than the first output torque, during the period from when the lower surface of the punch passes the midpoint between the top dead center and the bottom dead center until it reaches the bottom dead center, The torque control unit changes the output torque of the lifting motor from the first output torque to the second output torque after the lower surface of the punch passes the midpoint and before it contacts the upper surface of the metal plate.

2. An apparatus for manufacturing a laminated core in which a plurality of core members are stacked and bonded to one another, comprising: a lower die having a die with a die hole formed therein; an upper die having a punch corresponding to the die hole and punching a strip-shaped metal plate to form the core member; a mounting table that is arranged to be able to rise and fall and on which the formed core members are successively placed; a support member that supports the mounting table so that it can be raised and lowered; a lifting motor that raises and lowers the mounting table via the support member; a squeeze ring that is arranged below the die and applies lateral pressure to the core members placed on the mounting table; and a control device that controls the upper die and the lifting motor, wherein the control device has a torque control unit that changes the output torque of the lifting motor from a first output torque to a second output torque higher than the first output torque, during the period from when the lower surface of the punch passes the midpoint between the top dead center and the bottom dead center until it reaches the bottom dead center, The torque control unit changes the output torque of the lifting motor from the first output torque to the second output torque between the time when the iron core member formed by punching the metal plate starts to fall downward and the time when the lower surface of the punch reaches the bottom dead center.

3. The manufacturing apparatus of claim 2, wherein the torque control unit changes the output torque of the lifting motor from the first output torque to the second output torque during the period from when the iron core member formed by punching out the metal plate begins to fall downward until when the formed iron core member abuts against the upper surface of the iron core member placed on the mounting table.

4. The manufacturing apparatus of claim 2, wherein the torque control unit changes the output torque of the lifting motor from the first output torque to the second output torque during the period from when the iron core member formed by punching out the metal plate abuts against the upper surface of the iron core member placed on the mounting table until the lower surface of the punch reaches the bottom dead center.

5. A manufacturing apparatus for a laminated iron core in which a plurality of core members are stacked and bonded to each other, comprising: a lower mold having a die with a die hole formed therein; an upper mold having a punch corresponding to the die hole and punching a strip-shaped metal plate to form the core member; a mounting table that is arranged to be able to be raised and lowered and on which the formed core members are successively placed; a support member that supports the mounting table so that it can be raised and lowered; a lifting motor that raises and lowers the mounting table via the support member; and a control device that controls the upper mold and the lifting motor, wherein the control device has a torque control unit that changes the output torque of the lifting motor from a second output torque higher than the first output torque to the first output torque while the lower surface of the punch moves from the bottom dead center to the midpoint between the bottom dead center and the top dead center.

6. A manufacturing apparatus as described in claim 5, wherein the torque control unit changes the output torque of the lifting motor from the second output torque to the first output torque when the lower surface of the punch begins to rise from the bottom dead center.

7. The manufacturing device according to claim 5, wherein the torque control unit changes the output torque of the lift motor from the second output torque to the first output torque in a rectangular wave shape.

8. The manufacturing apparatus according to claim 5, wherein the torque control unit gradually changes the output torque of the lift motor from the second output torque to the first output torque.

9. A manufacturing apparatus as described in claim 5, wherein the timing at which the torque control unit changes the output torque of the lifting motor from the second output torque to the first output torque is the same in a first punching process in which the metal plate is punched with the punch to form a first piece of the iron core member, and a second punching process in which the metal plate is punched with the punch to form a second piece of the iron core member.

10. The manufacturing apparatus according to claim 5, wherein the torque control unit is configured to be able to change the first output torque.

11. The manufacturing apparatus described in claim 10, further comprising a squeeze ring disposed below the die and applying lateral pressure to the core material placed on the mounting table, and the torque control unit is configured to reduce the first output torque as the lateral pressure applied to the core material from the squeeze ring becomes smaller.

12. A manufacturing apparatus as described in claim 5, wherein the torque control unit is configured to be able to change the timing at which the output torque of the lifting motor is changed from the second output torque to the first output torque.

13. The manufacturing apparatus of claim 12, wherein the torque control unit is configured to be able to change the first output torque and is configured to delay the timing at which the change in the output torque of the lifting motor from the second output torque to the first output torque is completed as the first output torque becomes lower.

14. The manufacturing apparatus of claim 12, wherein the torque control unit is configured to be able to change at least one of the first output torque and the second output torque, and is configured to delay the timing at which the change in the output torque of the lifting motor from the second output torque to the first output torque is completed the greater the difference between the first output torque and the second output torque.

15. A manufacturing apparatus as described in claim 5, further comprising a pilot pin provided on the upper mold and inserted into a pilot hole formed in the metal plate to position the metal plate relative to the mounting table, and wherein the control device controls the descent and ascent of the punch so that the punch maintains a penetrating state with respect to the punched hole formed by punching the metal plate with the punch during the period from when the punch punches out the metal plate to when the output torque of the lifting motor is changed from the second output torque to the first output torque.

16. A manufacturing apparatus as described in claim 15, further comprising a stripper plate provided on the upper die and restricting the vertical movement of the metal plate when the metal plate is punched by the punch, and the control device controls the vertical movement of the stripper plate so as to restrict the vertical movement of the metal plate during at least a portion of a period during which the punch maintains a penetrating state relative to a punched hole formed by punching the metal plate with the punch.

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