Steel sheet punching apparatus and method for manufacturing laminated steel sheets

Abstract

The present invention provides a steel sheet punching device and a method for manufacturing laminated steel sheets that suppress oil depletion of the steel sheet on the downstream side in the conveying direction. [Solution] The steel sheet punching device 1 has an upper die 11 and a lower die 15 for punching out steel sheets SS, and includes a die 10 that receives steel sheets SS being transported in the transport direction DC between the upper die 11 and the lower die 15 and punches them out at multiple locations separated in the transport direction DC, and an oil supply unit 20 provided between the upstream and downstream ends of the die 10 in the transport direction DC for supplying oil to the steel sheets SS. The method for manufacturing laminated steel sheets involves supplying oil to the steel sheets SS supplied between the upper die 11 and the lower die 15 at least between the upstream and downstream ends of the die 10, sandwiching the steel sheets SS between the upper die 11 and the lower die 15 to punch out the steel sheets SS, and laminating a plurality of the punched steel sheets.

Description

Technical Field

[0001] The present disclosure relates to a steel sheet punching device and a method for manufacturing a laminated steel sheet.

Background Art

[0002] A motor core (a general term for a rotor core or a stator core) used in a motor mounted on an electric vehicle or the like is typically manufactured by laminating a plurality of core members punched from a long steel sheet.

[0003] Patent Document 1 describes a punching press provided with a guiding device for guiding a hoop material toward a processing section upstream of a processing section that continuously punches the hoop material sent in one direction, and an oil coating mechanism for coating oil on both the front and back surfaces of the hoop material on the guiding device.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, the punching press described in Patent Document 1 performs oil coating only upstream of the die (processing section), and as the steel material (hoop material) is conveyed, that is, the amount of oil decreases toward the downstream side in the conveyance direction, and oil shortage or depletion may occur on the downstream side of the device.

[0006] In view of the above problems, the present disclosure relates to providing a steel sheet punching device and a method for manufacturing a laminated steel sheet that suppress oil drainage of the steel sheet on the downstream side in the conveyance direction.

Means for Solving the Problems

[0007] A steel sheet punching apparatus according to a first aspect of the present disclosure comprises a die having an upper die and a lower die for punching out steel sheets, which receives the steel sheet being transported in the transport direction between the upper die and the lower die and punches it out at a plurality of locations separated in the transport direction, and an oil supply unit provided between the upstream and downstream ends of the die in the transport direction for supplying oil to the steel sheet.

[0008] With this configuration, the oil supply unit is located between the upstream and downstream ends of the mold in the conveying direction, allowing oil to be supplied to the steel plate as it is being conveyed through the mold, thereby suppressing oil depletion of the steel plate on the downstream side in the conveying direction.

[0009] Furthermore, as a steel sheet punching apparatus according to a second aspect of the present disclosure, in the steel sheet punching apparatus according to the first aspect of the present disclosure, the die has a first region for punching out rotor core pieces from the steel sheet and a second region for punching out stator core pieces from the steel sheet, wherein the first region is provided upstream of the second region in the conveying direction, and the oil supply unit may be arranged between the first region and the second region.

[0010] With this configuration, it becomes possible to supply the necessary oil even when punching out stator core pieces on the downstream side in the conveying direction.

[0011] Furthermore, as a steel sheet punching apparatus according to a third aspect of the present disclosure, in a steel sheet punching apparatus according to the first or second aspect of the present disclosure, the oil supply unit may supply the oil to the steel sheet in an intersecting direction that intersects with respect to the conveying direction.

[0012] With this configuration, it becomes possible to supply oil to the steel plates being transported in the transport direction in a predetermined width in the intersecting direction.

[0013] Furthermore, as a steel sheet punching apparatus according to a fourth aspect of the present disclosure, in the steel sheet punching apparatus according to the third aspect of the present disclosure, the oil supply unit has a plurality of nozzles having discharge ports for discharging the oil formed at predetermined intervals, and the plurality of nozzles may be arranged in the intersecting direction.

[0014] This configuration suppresses the occurrence of differences in discharge flow rates due to differences in discharge pressure at each discharge port, which can occur when supplying oil from multiple discharge ports formed on a single nozzle, and thus suppresses variations in the amount of oil discharged from each discharge port.

[0015] Furthermore, as a steel sheet punching apparatus according to a fifth aspect of the present disclosure, in a steel sheet punching apparatus according to any one of the first to fourth aspects of the present disclosure, the oil supply unit may supply the oil to the steel sheet in a mist form.

[0016] This configuration allows for the supply of oil over a wide area of ​​the steel plate.

[0017] Furthermore, as a steel sheet punching apparatus according to a sixth aspect of the present disclosure, in a steel sheet punching apparatus according to any one of the first to fifth aspects of the present disclosure, the oil supply unit may be positioned at least above the steel sheet being transported between the upper die and the lower die.

[0018] With this configuration, oil supplied from above the steel plate may reach the underside of the steel plate when it moves downward due to gravity, thus supplying oil to the underside of the steel plate.

[0019] Furthermore, as a steel sheet punching apparatus according to the seventh aspect of the present disclosure, in a steel sheet punching apparatus according to any one of the first to sixth aspects of the present disclosure, the steel sheet may be conveyed intermittently by a predetermined distance in the conveying direction, and the oil supply unit may supply oil to the steel sheet when the steel sheet is being conveyed in the conveying direction.

[0020] With such a configuration, oil can be continuously supplied to the steel sheet in the conveying direction.

[0021] The method for manufacturing a laminated steel sheet according to the eighth aspect of the present disclosure includes a step of supplying oil to the steel sheet supplied between the upper die and the lower die of a die having an upper die and a lower die for punching the steel sheet, at least between the upstream end and the downstream end of the die in the conveying direction of the steel sheet; a step of sandwiching the steel sheet between the upper die and the lower die and punching the steel sheet; and a step of laminating a plurality of the punched steel sheets.

[0022] With such a configuration, since oil is supplied to the steel sheet between the upstream end and the downstream end of the die in the conveying direction, oil can be supplied to the steel sheet while it is being conveyed inside the die, and oil starvation of the steel sheet on the downstream side in the conveying direction can be suppressed.

Advantages of the Invention

[0023] According to the present disclosure, since oil is supplied to the steel sheet between the upstream end and the downstream end of the die in the conveying direction, oil can be supplied to the steel sheet while it is being conveyed inside the die, and oil starvation of the steel sheet on the downstream side in the conveying direction can be suppressed.

Brief Description of the Drawings

[0024] [Figure 1] It is a side view showing a schematic configuration of a steel sheet punching device according to the first embodiment of the present disclosure. [Figure 2] It is a plan view showing a schematic configuration of a steel sheet punching device according to the first embodiment of the present disclosure. [Figure 3] It is a flowchart showing an example of a procedure in a method for manufacturing a laminated steel sheet according to the second embodiment of the present disclosure. [Figure 4] It is a flowchart exemplifying a procedure in a method for manufacturing a laminated steel sheet according to the first modification of the second embodiment of the present disclosure. [Figure 5] It is a flowchart exemplifying a procedure in a method for manufacturing a laminated steel sheet according to the second modification of the second embodiment of the present disclosure. [Modes for carrying out the invention]

[0025] Embodiments of this disclosure will be described below with reference to the drawings. In each drawing, identical or equivalent components are denoted by the same or similar reference numerals, and redundant explanations are omitted. Also, the dimensions and proportions in the drawings are exaggerated for illustrative purposes and may differ from actual proportions.

[0026] First, a steel sheet punching apparatus 1 according to the first embodiment of this disclosure will be described with reference to Figures 1 and 2. Figure 1 is a side view showing the schematic configuration of the steel sheet punching apparatus 1. Figure 2 is a plan view showing the schematic configuration of the steel sheet punching apparatus 1. The steel sheet punching apparatus 1 is a device that manufactures parts by punching out steel sheets SS in stages. In this embodiment, the parts manufactured by the steel sheet punching apparatus 1 are laminated steel sheets used as rotor cores or stator cores that constitute a motor core. The steel sheet punching apparatus 1 manufactures laminated steel sheets by punching out core pieces that constitute these laminated steel sheets and stacking them. In the following description, core pieces used in rotor cores will also be called "rotor core pieces," and core pieces used in stator cores will also be called "stator core pieces." Accordingly, the steel sheet SS is typically an electromagnetic steel sheet formed in a long strip in one direction. The steel sheet punching apparatus 1 is equipped with a die 10 and an oil nozzle 20. In this embodiment, the steel sheet punching device 1 also includes a conveying device 31 and a control device 50. While electrical steel sheet is used as the steel sheet SS here, the technology of this disclosure is not limited to this and may also be applied to amorphous steel sheet.

[0027] The die 10 receives steel sheets SS being transported in the transport direction DC and punches out the received steel sheets SS. The transport direction DC is the direction in which a long steel sheet SS is transported along its longitudinal direction, and in this embodiment, it is the direction along the longitudinal direction of the die 10. As shown in Figure 1, the die 10 has an upper die 11 and a lower die 15. In Figure 2, the upper die 11 is shown with a dashed line to show the internal structure of the steel sheet punching device 1. In this embodiment, the upper die 11 includes a first upper die 12 and a second upper die 13. In this embodiment, the first upper die 12 and the second upper die 13 are configured as separate parts that are divided from each other. The first upper die 12 is located upstream of the second upper die 13 in the transport direction DC. Hereafter, when describing common matters concerning the first upper die 12 and the second upper die 13, they will be collectively referred to as "upper die 11". In this embodiment, the upper die 11 and lower die 15 are arranged vertically vertically, with the upper die 11 positioned above the lower die 15. The upper die 11 has a punch, and the lower die 15 has a die. In this embodiment, a progressive die is used for the mold 10, and multiple sets of punches for the upper die 11 and dies for the lower die 15 are provided.

[0028] As shown in Figure 2, the first upper die 12, in this embodiment, is a die that works in cooperation with the lower die 15 to punch out rotor core pieces, punching out steel plates SS at six positions P11, P12, P13, Q11, Q12, and Q13 in a single press. At positions P11, P12, and P13, dies (i.e., punches and dies) suited to the shape to be punched out at each position are provided in this order from the upstream side to the downstream side in the conveying direction DC. In this embodiment, at position P11, the shaft insertion hole formed inside the rotor core is punched out. At position P12, the peripheral hole formed around the shaft insertion hole is punched out. At position P13, the outer edge of the rotor core piece is punched out. When the outer edge of the rotor core piece is punched out at position P13, the rotor core piece, which is a component, is separated from the steel plate SS. Below the die of the lower die 15 at position P13, a squeeze (not shown) is typically provided to receive the punched rotor core piece. Within the squeeze chamber, punched rotor core pieces are stacked to form a laminated steel plate.

[0029] At positions Q11, Q12, and Q13, molds (i.e., punches and dies) suited to the shape to be punched out at each position are provided in this order from upstream to downstream in the transport direction DC. Furthermore, positions Q11, Q12, and Q13 are arranged in a direction intersecting the transport direction DC with respect to positions P11, P12, and P13. At positions Q11, Q12, and Q13, rotor core pieces with the same shape as those at positions P11, P12, and P13 are punched out, respectively. Therefore, the mold 10 in this embodiment can produce two rotor core pieces simultaneously. Below the die of the lower mold 15 at position Q13, a squeeze (not shown) is typically provided, similar to the area below the die at position P13.

[0030] The six locations P11, P12, P13, Q11, Q12, and Q13 where the rotor core pieces are punched out together constitute the first region. The above description of the first upper die 12 shows an example in which one rotor core piece is produced by punching out the steel plate SS in three steps. However, the number of times the steel plate SS is punched out in steps to produce one rotor core piece can be increased or decreased as appropriate, such as two or fewer times, or four or more times, depending on the shape of the rotor core piece to be produced.

[0031] In this embodiment, the second upper die 13 is a die that works in cooperation with the lower die 15 to punch out stator core pieces, punching out steel plates SS at six locations P21, P22, P23, Q21, Q22, and Q23 in a single press. At locations P21, P22, and P23, dies (i.e., punches and dies) suited to the shape to be punched out at each location are provided in this order from upstream to downstream in the conveying direction DC. In this embodiment, at location P21, the cavity formed inside the stator core piece is punched out. At location P22, the unnecessary parts around the teeth are punched out in order to form the teeth. At location P23, the outer edge of the stator core piece is punched out. When the outer edge of the stator core piece is punched out at location P23, the stator core piece, which is a component, is separated from the steel plate SS. Below the die of the lower die 15 at location P23, a squeeze (not shown) is typically provided to receive the punched stator core piece. Within the squeeze chamber, punched stator core pieces are stacked to form a laminated steel plate.

[0032] At positions Q21, Q22, and Q23, molds (i.e., punches and dies) suited to the shape to be punched out at each position are provided in this order from upstream to downstream in the conveying direction DC. Furthermore, positions Q21, Q22, and Q23 are arranged in a direction intersecting the conveying direction DC with respect to positions P21, P22, and P23. At positions Q21, Q22, and Q23, stator core pieces with the same shape as those at positions P21, P22, and P23 are punched out, respectively. Therefore, the mold 10 in this embodiment can produce two stator core pieces simultaneously. Below the die of the lower mold 15 at position Q23, a squeeze (not shown) is typically provided, similar to the area below the die at position P23. Note that at positions P21 and Q21, in this embodiment, the steel plate SS after the rotor core piece has been punched out is punched out. In other words, the steel plate SS surrounding the area where the rotor core piece has been punched out is used as the stator core piece. Thus, in this embodiment, the rotor core piece and the stator core piece are manufactured together.

[0033] The six locations P21, P22, P23, Q21, Q22, and Q23 where the stator core pieces are punched out, collectively constitute a second region. The second region is located at the position of the second upper die 13, while the first region is located at the position of the first upper die 12. Since the first upper die 12 and the second upper die 13 are located at different positions in the transport direction DC, the first region and the second region are located at different locations in the transport direction DC. The above description of the second upper die 13 shows an example of generating one stator core piece by punching out the steel plate SS in three steps. However, the number of times the steel plate SS is punched out in steps to generate one stator core piece can be increased or decreased as appropriate, such as two or fewer times, or four or more times, depending on the shape of the generated stator core piece.

[0034] The three positions P11, P12, and P13 for punching out the rotor core pieces are arranged such that the arrangement (i.e., the imaginary line connecting the three positions) is parallel to the transport direction DC, and the distance between position P11 and position P12 is equal to the distance between position P12 and position P13. Here, the distance between position P11 (or P12) and position P12 (or P13) is the distance between their respective reference positions (e.g., the center of gravity of the punch and / or die in a plan view), and this is referred to as the "transport pitch L". Similarly, the three positions Q11, Q12, and Q13 are arranged such that the arrangement is parallel to the transport direction DC, and the distance between them is the transport pitch L. Similarly, the three positions P21, P22, and P23 for punching out the stator core pieces, and the three positions Q21, Q22, and Q23 are arranged such that the arrangement is parallel to the transport direction DC, and the distance between them is the transport pitch L. In this embodiment, the distance between position P13 and position P21, which straddles the boundary between the first upper mold 12 and the second upper mold 13, is a length mL (where m is an integer) that is an integer multiple of the transport pitch L, which is greater than the transport pitch L. Similarly, the distance between position Q13 and position Q21 is a length nL (where n is an integer) that is an integer multiple of the transport pitch L, which is greater than the transport pitch L, in this embodiment. Length mL and length nL may be the same length (i.e., m=n). Alternatively, length mL and / or length nL may be the same length as the transport pitch L (i.e., m=1 and / or n=1).

[0035] In this embodiment, the die 10 punches out the steel sheet SS supplied between the upper die 11 and the lower die 15 by bringing the upper die 11 closer to the lower die 15. For this purpose, the upper die 11 is equipped with a press machine 33 that moves the upper die 11 closer to and further away from the lower die 15 (in this embodiment, by moving the upper die 11 up and down). Note that in Figure 2, the press machine 33 is not shown in order to show the internal structure of the steel sheet punching device 1. When the upper die 11 moves up and down by the press machine 33, all the punches on the upper die 11 move up and down. When the upper die 11 moves up and down by the press machine 33, the punches on the upper die 11 rotate around a vertically extending axis. The press machine 33 is also equipped with an encoder (not shown), which can determine the vertical position of the upper die 11 by detecting the angle around the axis of the punch. In addition to the press machine 33, the surrounding components of the die 10 include, although not shown in the diagram, well-known components in the field of progressive press dies, such as a stripper for removing material attached to the punch, a spring for supporting the stripper, a lifter for raising the steel plate SS from the lower die 15 when transporting the steel plate SS, a guide pin for guiding the vertical movement of the punch, and a positioning pin for horizontal positioning.

[0036] The oil nozzle 20 supplies processing oil (hereinafter simply referred to as "oil") to the steel sheet SS. The oil nozzle 20 is located above the steel sheet SS supplied between the upper die 11 and the lower die 15, between the first upper die 12 and the second upper die 13 (i.e., between the first region and the second region). The space between the first upper die 12 and the second upper die 13 where the oil nozzle 20 is located is between the upstream and downstream ends of the mold in the conveying direction DC, so the oil nozzle 20 corresponds to the oil supply section. By providing the oil nozzle 20 between the first upper die 12 and the second upper die 13, even when the mold 10 becomes larger when both rotor core pieces and stator core pieces are processed together, a shortage or depletion of oil on the downstream side of the conveying direction DC can be suppressed.

[0037] The oil nozzle 20 is typically formed in an elongated cylindrical shape. The size of the oil nozzle 20 is often determined considering its interaction with the mold 10, and for example, the cylindrical outer diameter may be 3 mm to 10 mm or 5 mm to 7 mm. With the oil nozzle 20 configured in this way, it is possible to install the oil nozzle 20 in the space between the first upper mold 12 and the second upper mold 13 even when the space is relatively narrow. The oil nozzle 20 also has an outlet 23 for discharging oil toward the steel plate SS. In this embodiment, the outlet 23 has a structure that supplies oil to the steel plate SS in a mist form. By configuring the outlet 23 to spray the oil, the oil can be applied thinly and evenly to the steel plate SS compared to when it is dripped. In this embodiment, multiple outlets 23 are formed on the oil nozzle 20 at predetermined intervals. In this embodiment, the predetermined interval is such that oil can be supplied to a predetermined area (e.g., the entire area) of the steel plate SS in the orthogonal direction DP at the position where the oil nozzle 20 is located. The orthogonal direction DP is a direction that extends horizontally and perpendicularly to the conveying direction DC, and is a form of intersecting direction. The oil nozzle 20 is equipped with a valve 24 that can shut off the oil flow path upstream of the discharge port 23, which is located at the uppermost point in the oil flow direction. The oil nozzle 20 can switch between spraying oil from the discharge port 23 and not by opening and closing the valve 24.

[0038] As shown in Figure 2, in this embodiment, the oil nozzle 20 is divided into two parts in the orthogonal direction DP, consisting of two parts: oil nozzle 20P and oil nozzle 20Q. In other words, oil nozzle 20P and oil nozzle 20Q are arranged in series in the orthogonal direction DP. The reason for this division is that in the mold 10, two sets of multiple shapes arranged in the transport direction DC to produce one rotor core piece or stator core piece are arranged side by side in the orthogonal direction DP, and the length of the steel plate SS in the orthogonal direction DP is relatively long. By dividing the oil nozzle 20 into two parts in the orthogonal direction DP, it is possible to suppress differences in oil discharge pressure (or discharge flow rate) between the multiple discharge ports 23 formed in each nozzle. In each nozzle of the oil nozzle 20, for example, in oil nozzle 20P, there may be, for example, 3 to 5 discharge ports 23 formed at predetermined intervals, or 4, or any other number depending on the length.

[0039] In this embodiment, the oil supply mechanism 26 is also provided to supply oil to the steel plate SS upstream of the mold 10 in the transport direction DC. In this embodiment, the oil supply mechanism 26 is positioned above and below the steel plate SS upstream of the mold 10 in the transport direction DC, but it may be positioned only above the steel plate SS and not below it. The oil supply mechanism 26 may be configured as an elongated cylindrical nozzle similar to the oil nozzle 20 with multiple discharge ports, or it may be configured to supply oil to the steel plate SS using a coating roller.

[0040] The conveying device 31 conveys the steel plate SS in the conveying direction DC. The conveying device 31 has a pair of rollers that sandwich the steel plate SS in the thickness direction (up and down direction in this embodiment). Typically, the conveying device 31 has a pair of rollers that are each formed in a cylindrical shape and rotated around a cylindrical axis by a motor. The conveying device 31 can change the rotational speed of the pair of rollers in response to a command from the control device 50. Changing the rotational speed of the pair of rollers includes setting the rotational speed to 0 (i.e., stopping the rotation). The steel plate SS sandwiched between the pair of rollers of the conveying device 31 is conveyed in accordance with the rotation of the pair of rollers, and the steel plate SS is supplied between the upper die 11 and the lower die 15.

[0041] The control device 50 controls the operation of each of the above-described devices (or components) that constitute the steel sheet punching machine 1. The control device 50 is connected to each component via wired or wireless communication, for example, as shown by dashed lines in Figures 1 and 2 (excluding the dashed lines for the first upper die 12 and the second upper die 13). A specific example of the control device 50's control of each component of the steel sheet punching machine 1 is as follows: The control device 50 controls the rotational speed of a pair of rollers of the conveying device 31 to intermittently convey the steel sheet SS to the conveying device 31 by a predetermined distance. The predetermined distance is the distance between adjacent punches and dies in the conveying direction DC provided on the mold 10 (i.e., the conveying pitch L). In other words, the control device 50 controls the conveying device 31 to move the steel sheet SS by the conveying pitch L in the conveying direction DC. The control device 50 also controls the press machine 33 to move the upper die 11 up and down. At this time, the control device 50 determines the vertical position of the upper die 11 based on the punch angle detected by an encoder (not shown) provided on the press machine 33. The control device 50 also controls the opening and closing of the valve 24 to adjust the oil supply flow rate from the oil nozzle 20. The control device 50 also adjusts the oil supply flow rate from the oil supply mechanism 26 using a known flow rate adjustment mechanism.

[0042] The control device 50 may employ a computer including a programmable logic controller (PLC). The control device 50 may include at least one physical configuration of a processor 51, memory 52 (RAM and / or ROM), and storage 53. Furthermore, the control device 50 may have, for example, memory 52 and / or storage 53 containing a program for properly operating each of the above-mentioned devices, and the processor 51 may be used to execute this program. Each component of the control device 50 (including at least one of the processor 51, memory 52, and storage 53) is typically connected to each other by a bus, such as a system bus or a control bus, and can communicate with each other.

[0043] In the above description, "processor" refers to a processor in a broad sense, including general-purpose processors (e.g., CPU: Central Processing Unit, etc.) and dedicated processors (e.g., GPU: Graphics Processing Unit, ASIC: Application Specific Integrated Circuit, FPGA: Field Programmable Gate Array, programmable logic device, etc.). Furthermore, the operation of the processor in this disclosure may not be performed by a single processor, but may be performed by multiple processors located in physically separate locations working together. In addition, the order of each operation of the processor is not limited to the order described in this disclosure and may be changed as appropriate.

[0044] Furthermore, the above program may be provided on a computer-readable non-temporary recording medium such as a USB (Universal Serial Bus) memory, flexible disk, or CD-ROM (Compact Disc Read Only Memory), or it may be provided online via a network such as the Internet. In this case, the program recorded on the computer-readable non-temporary recording medium is usually transferred to memory or storage and stored. This program may also be provided, for example, as a standalone application software, or it may be incorporated into the software of each device as a function of the device. The program referred to in this disclosure can be provided as a program product. A program product includes any form of product for providing a program. For example, a program product includes a program provided via a network such as the Internet, and a non-temporary computer-readable recording medium such as a CD-ROM or DVD on which the program is stored.

[0045] Next, with reference to Figure 3, a method for manufacturing laminated steel sheets according to a second embodiment of the present disclosure will be described. Figure 3 is a flowchart showing an example of the manufacturing procedure for laminated steel sheets. Laminated steel sheets are formed by laminating steel sheets that have been punched out and separated from a long steel sheet SS, and in this embodiment, this corresponds to a rotor core and a stator core. In the following description, an example will be given of manufacturing laminated steel sheets using the steel sheet punching device 1 described above. Note that the method for manufacturing laminated steel sheets of the present disclosure can be implemented in devices other than the steel sheet punching device 1, but which are equipped with a die having an upper die and a lower die. The description of the method for manufacturing laminated steel sheets according to this embodiment, which is realized by the steel sheet punching device 1, also serves as a description of the operation of the steel sheet punching device 1. In addition, when the configuration of the steel sheet punching device 1 is referred to in the following description, Figures 1 and 2 will be referred to as appropriate. In the following method for manufacturing laminated steel sheets, the operation of each device and equipment constituting the steel sheet punching device 1 is typically performed based on commands from the control device 50. The method for manufacturing laminated steel sheets according to this embodiment may be provided in the form of a program (including a program product) for causing the processor 51 of a control device 50 that controls each component of the steel sheet punching device 1 to perform a predetermined operation, or in the form of a non-temporary computer-readable medium storing this program.

[0046] When the steel sheet punching machine 1 is stopped, typically the upper die 11 is raised and away from the lower die 15, and the spraying of oil from the oil nozzle 20 and oil supply mechanism 26, as well as the rotation of the pair of rollers in the conveying device 31, are also stopped. Also, typically the steel sheet punching machine 1 is stopped from the previous operation, and steel sheet SS is supplied between the upper die 11 and the lower die 15. If there is no steel sheet SS between the upper die 11 and the lower die 15, it is advisable to supply steel sheet SS between the upper die 11 and the lower die 15 before starting the production of laminated steel sheets. To start the production of laminated steel sheets, first the steel sheet punching machine 1 is started (S1). Then the control device 50 starts the operation of the press machine 33, which starts the operation of the upper die 11. Once the operation of the upper die 11 is started, in this embodiment, it moves up and down repeatedly until the steel sheet punching machine 1 stops. Furthermore, the control device 50 opens the valve 24, thereby initiating the supply of oil from the oil nozzle 20 to the steel plate SS (S2). At this time, the oil is supplied to the steel plate SS in a mist form from each discharge port 23 of the oil nozzle 20, so that it is supplied evenly to a predetermined area (for example, the entire area) in the width direction (i.e., the orthogonal direction DP) of the steel plate SS. Also, since the oil is supplied in the middle of the mold 10, it is possible to suppress oil shortage or depletion in the steel plate SS in the downstream part of the mold 10. In this embodiment, the oil is supplied in the middle of the mold 10 only from above the steel plate SS, but since the steel plate SS to which oil is sprayed at this position has holes left by the rotor core pieces punched out in the first upper mold 12, the oil supplied to the top of the steel plate SS can flow around to the bottom surface of the steel plate SS. In addition, in this embodiment, oil is supplied to the steel plate SS from the oil supply mechanism 26 in synchronization with the supply of oil from the oil nozzle 20 to the steel plate SS. By supplying oil to the steel sheet SS from the oil nozzle 20 and the oil supply mechanism 26, oil shortage or depletion can be suppressed throughout the steel sheet SS at the location where it is punched out by the die 10. In this embodiment, once the supply of oil to the steel sheet SS is started, the oil supply continues until the steel sheet punching device 1 stops.

[0047] Once the supply of oil to the steel plate SS begins, the control device 50 operates the conveying device 31 at a predetermined timing to rotate a pair of rollers by a predetermined angle, thereby moving the steel plate SS in the conveying direction DC by a length of conveying pitch L (S3). Here, the predetermined timing is typically the time period when the upper die 11 is not in contact with the steel plate SS. The predetermined angle is the rotation angle of the rollers required to move the steel plate SS by the length of conveying pitch L. The length of the conveying pitch L corresponds to a predetermined distance. While the steel plate SS is moving in the conveying direction DC by the length of conveying pitch L, the supply of oil to the steel plate SS from the oil nozzles 20 and the oil supply mechanism 26 continues. Therefore, the steel plate SS is coated with oil over a predetermined area (e.g., the entire area) in the width direction (i.e., the orthogonal direction DP), from the part corresponding to the arrangement of the oil nozzles 20 and the oil supply mechanism 26 before movement to the part corresponding to the length of conveying pitch L upstream in the conveying direction DC. The control device 50 may also change the flow rate of oil supplied from the oil nozzle 20 to the steel plate SS according to the transport speed of the steel plate SS in the transport direction DC. For example, the flow rate of oil may be changed to be proportional to the transport speed, such that the flow rate of oil is lower when the transport speed is low and higher when the transport speed is high. In this way, the amount of oil applied per unit area of ​​the steel plate SS can be made uniform. Similarly, the flow rate of oil supplied from the oil supply mechanism 26 to the steel plate SS may also be changed according to the transport speed of the steel plate SS in the transport direction DC.

[0048] When the steel plate SS has finished moving by the length of the transport pitch L, the upper die 11 is typically in the process of descending. As the upper die 11 descends, it sandwiches the steel plate SS between itself and the lower die 15, and then the punch of the upper die 11 engages with the die of the lower die 15 to punch out the steel plate SS (S4). In this embodiment, punching out the steel plate SS is performed simultaneously at each of the 12 positions P11, P12, P13, Q11, Q12, Q13, P21, P22, P23, Q21, Q22, and Q23. As described above, the first stage of punching out rotor core pieces is performed at positions P11 and Q11, the second stage of punching out rotor core pieces is performed at positions P12 and Q12, and the outer edge of the rotor core pieces is punched out at positions P13 and Q13 and accommodated in the lower squeeze (not shown). Furthermore, the first stage of punching for the stator core pieces is performed at positions P21 and Q21, the second stage of punching for the stator core pieces is performed at positions P22 and Q22, and the outer edges of the stator core pieces are punched at positions P23 and Q23 and housed in the lower squeeze (not shown). The upper die 11, which had been descending, turns upward after the punch engages with the die and punches out the steel plate SS, and continues to move up and down thereafter.

[0049] Of the rotor core pieces and stator core pieces punched out by the punch of the upper die 11 and housed in each squeeze (not shown), the rotor core pieces are stacked on top of the rotor core pieces already housed, and the stator core pieces are stacked on top of the stator core pieces already housed (S5). In this embodiment, the stacked iron core pieces may be joined to each other (for example, by riveting). In this embodiment, since oil is supplied to the steel plate SS in a mist form from the oil nozzle 20 and the oil supply mechanism 26, the oil is applied uniformly to the steel plate SS, preventing oil accumulation and preventing the formation of gaps between rotor core pieces and stator core pieces during joining. In other words, in this embodiment, the inconvenience of the oil film thickness (i.e., oil accumulation) increasing when oil is supplied to the steel plate SS by dripping, causing gaps to form due to the oil film during joining, can be avoided. When the number of rotor core pieces and stator core pieces stacked in each squeeze (not shown) reaches the planned number, a stacked steel plate is manufactured. The manufactured laminated steel sheets are removed from the squeeze (not shown) and transported to the appropriate location where subsequent processes take place, where they undergo predetermined treatment to become a rotor core or stator core.

[0050] As described above, while the rotor core pieces and stator core pieces are being punched out from the steel sheet SS (S4) and stacked (S5), the control device 50 determines whether or not it has received a command to stop the steel sheet punching device 1 (S6). If it has not received a command to stop (NO in step S6), it returns to the step of moving the steel sheet SS in the transport direction DC by the transport pitch L (S3), and thereafter repeats each of the above steps (S3 to S6). In this way, the steel sheet punching device 1 repeats this series of steps (S3 to S6) until it receives a command to stop. The steel sheet SS moves intermittently in the transport direction DC by the transport pitch L each time the series of steps (S3 to S6) is completed. As a result, for example, the part of the steel sheet SS that was initially punched out at position P11 will be punched out at position P12 in the next series of steps (S3 to S6), and then at position P13 in the following series of steps (S3 to S6). Thus, in this embodiment, a rotor core piece is generated by punching out a portion of the steel sheet SS three times at different positions. The same applies to the stator core piece. As mentioned above, the number of times the steel sheet SS is punched out to generate one rotor core piece or stator core piece can be appropriately determined depending on the shape to be punched out, etc.

[0051] In the step (S6) of determining whether or not a command to stop the steel sheet punching device 1 has been received, if a command to stop has been received (YES in step S6), the control device 50 closes the valve 24, thereby stopping the supply of oil from the oil nozzle 20 to the steel sheet SS (S7). In this embodiment, the supply of oil from the oil supply mechanism 26 to the steel sheet SS is also stopped in synchronization with the stopping of the supply of oil from the oil nozzle 20 to the steel sheet SS. Once the supply of oil to the steel sheet SS is stopped, the control device 50 stops the steel sheet punching device 1 (S8). The stopping of the steel sheet punching device 1 is accompanied by the stopping of the operation of the press machine 33, and consequently the stopping of the operation of the upper die 11. In the example shown in Figure 3, for the sake of explanation, the steel sheet punching device 1 is stopped (S8) after the supply of oil to the steel sheet SS is stopped (S7), but these may be performed simultaneously. The stopping of the steel sheet punching device 1 completes the manufacturing of the laminated steel sheet. If the control device 50 later receives a command to start the steel sheet punching device 1, it will start the steel sheet punching device 1 and then execute the process described above.

[0052] In the example shown in Figure 3, once the steel sheet punching machine 1 is started and the supply of oil to the steel sheet SS begins (S2), the supply of oil to the steel sheet SS continues until the supply of oil is stopped before the steel sheet punching machine 1 stops (S7). Alternatively, the supply of oil may be started and stopped according to the transport status of the steel sheet SS.

[0053] Figure 4 is a flowchart illustrating the manufacturing procedure for laminated steel sheets according to the first modified example. The modified example shown in Figure 4 differs from the manufacturing method illustrated in Figure 3 in the following ways. First, the step of stopping the supply of oil to the steel sheet SS (S7) is performed after the step of moving the steel sheet SS in the transport direction DC by the length of the transport pitch L (S3), and before the step of punching out the steel sheet SS (S4). Accordingly, in the step of determining whether or not a command to stop the steel sheet punching device 1 has been received (S6), if a command to stop has been received (YES in step S6), the process proceeds to the step of stopping the steel sheet punching device 1 (S8). Also, in the step of determining whether or not a command to stop the steel sheet punching device 1 has been received (S6), if a command to stop has not been received (NO in step S6), the process returns to the step of starting the supply of oil to the steel sheet SS (S2) instead of the step of moving the steel sheet SS by the length of the transport pitch L (S3). Except for the changes in order shown above, the content and order of each step are the same as the manufacturing method illustrated in Figure 3. In the first modified example shown in Figure 4, the start (S2) and stop (S7) of the oil supply to the steel plate SS may be performed based on the rotation angle of a pair of rollers in the conveying device 31. In addition, in the modified example shown in Figure 4, the step of stopping the oil supply to the steel plate SS (S7) may be performed before the step of moving the steel plate SS by the length of the conveying pitch L (S3) or in the middle of this step (S3). According to the manufacturing method of the modified example shown in Figure 4, by stopping the oil supply to the steel plate SS when the movement of the steel plate SS has stopped, it is possible to prevent excessive oil supply.

[0054] As a second modification, the start and stop of the oil supply to the steel plate SS may be linked to the vertical movement of the upper die 11. In this case, the control device 50 can receive signals from an encoder (not shown) provided on the press machine 33 to determine the vertical position of the upper die 11. In this case, the control device 50 may start supplying oil from the oil nozzle 20 to the steel plate SS when it determines that the rising upper die 11 has reached a predetermined position. The predetermined position is typically the top dead center of the upper die 11 after the punch has left the steel plate SS. Figure 5 shows a flowchart of the case where the start and stop of the oil supply to the steel plate SS is linked to the vertical movement of the upper die 11.

[0055] Figure 5 is a flowchart illustrating the manufacturing procedure for a laminated steel sheet according to a second modified example. The second modified example shown in Figure 5 differs from the first modified example shown in Figure 4 in the following respects. First, after the step of starting the steel sheet punching machine 1 (S1), the procedure includes a step of detecting that the upper die 11 has reached a predetermined position (S1A), and after this step (S1A), the procedure proceeds to the step of starting the supply of oil to the steel sheet SS (S2). The step of stopping the supply of oil to the steel sheet SS (S7) is typically performed when it is detected that the upper die 11 has started to move from a predetermined position (typically top dead center) (or has reached a predetermined amount of rotation). However, the step of stopping the supply of oil (S7) may be performed when a predetermined amount of time has elapsed since the step of starting the supply of oil (S2), or based on the rotation angle of a pair of rollers in the conveying device 31. Furthermore, in the step (S6) of determining whether or not a command to stop the steel sheet punching device 1 has been received, if no command to stop has been received (NO in step S6), the process returns to the step (S1A) of detecting that the upper die 11 has reached a predetermined position, instead of the step (S2) of starting the supply of oil to the steel sheet SS. Except for the change in order shown above, the process is the same as the first modified example shown in Figure 3, including the content and order of each step. In the second modified example shown in Figure 5, the step (S7) of stopping the supply of oil to the steel sheet SS may be performed before the step (S3) of moving the steel sheet SS by the length of the transport pitch L, or in the middle of this step (S3). In the manufacturing method according to the second modified example shown in Figure 5, as in the manufacturing method according to the first modified example shown in Figure 4, excessive supply of oil can be prevented by stopping the supply of oil to the steel sheet SS when the movement of the steel sheet SS has stopped.

[0056] As described above, the steel sheet punching apparatus 1 and the method for manufacturing laminated steel sheets according to this embodiment have the following advantages. Since an oil nozzle 20 is provided between the first upper die 12 having a punch for punching one rotor core and the second upper die 13 having a punch for punching one stator core, oil can be supplied to the steel sheet SS in the middle of the die 10 in the conveying direction DC, and oil shortage or depletion downstream can be suppressed. In addition, since the oil nozzle 20 having a plurality of discharge ports 23 is arranged in the width direction of the steel sheet SS (i.e., the orthogonal direction DP), even if the width of the steel sheet SS is wide, oil can be supplied to a predetermined area (for example, the entire area) in the width direction of the steel sheet SS. Furthermore, since oil is supplied to the steel sheet SS from the oil nozzle 20 in a mist form, it is possible to supply oil generally uniformly in the width direction of the steel sheet SS. Furthermore, if oil is continuously supplied to the steel plate SS while it is being moved in the conveying direction DC, and the supply of oil to the steel plate SS is stopped when the movement of the steel plate SS in the conveying direction DC stops and the punching operation by the upper die 11 is being performed, then excessive oil supply can be prevented.

[0057] In the above description, it was assumed that the mold 10 produces two rotor core pieces and two stator core pieces in one press. However, the number of rotor core pieces and stator core pieces produced in one press may be one each, or three or more each.

[0058] In the above description, it was assumed that the oil nozzle 20 is divided into two parts in the orthogonal direction DP, but depending on the width of the steel plate SS, it may not be divided, or it may be divided into three or more parts. Also, depending on the configuration of the steel plate punching device 1, the oil nozzle 20 may be arranged to extend in a direction that is inclined to the orthogonal direction DP.

[0059] In the above description, the oil nozzle 20 is assumed to be located above the steel plate SS as the oil supply unit. However, in addition to this oil nozzle 20, an additional oil nozzle may be located below the steel plate SS. If an additional oil nozzle is provided and the lower mold 15 is not divided like the upper mold 11, a recess (or groove) capable of accommodating the additional oil nozzle may be formed in the upper part of the lower mold 15.

[0060] In the above description, it was assumed that the upper mold 11 is divided into a first upper mold 12 and a second upper mold 13, but the first upper mold 12 and the second upper mold 13 may be formed as a single unit. If the first upper mold 12 and the second upper mold 13 are formed as a single unit, it is preferable to form a recess (or groove) capable of accommodating the oil nozzle 20 between the first upper mold 12 and the second upper mold 13.

[0061] In the above description, the oil nozzle 20 is assumed to be a nozzle formed in an elongated cylindrical shape. However, any configuration that can supply oil in the orthogonal direction DP may be a drip-type or coating roller type oil supply. Nevertheless, considering the ease of installation in the space between the first upper mold 12 and the second upper mold 13, a nozzle is preferred.

[0062] In the above description, the oil nozzle 20 is assumed to be located in the space between the first upper mold 12 and the second upper mold 13. However, it is not limited to this configuration, and may be located inside the first mold 12 or the second mold 13 between multiple processing stages. For example, if one of the first mold 12 and the second mold 13 is longer than the other in the transport direction DC, the oil nozzle 20 may be provided in the longer mold.

[0063] Furthermore, this disclosure may be implemented with various modifications without departing from its essence. All such modifications are included in the technical concept of this disclosure. [Explanation of Symbols]

[0064] 1. Steel plate punching machine 10 molds 11 Upper mold 12. Type 1 Upper 13. Type 2 Upper 15 Lower mold 20 oil nozzles 23. Third oil nozzle (oil supply unit) 25 Outlet DC transport direction DP (Diagram of DP) in orthogonal directions (intersecting directions) SS steel plate

Claims

1. A die having an upper die and a lower die for punching out steel plates, which receives the steel plates being transported in the transport direction between the upper die and the lower die and punches them out at multiple locations separated in the transport direction, The system includes an oil supply unit provided between the upstream and downstream ends of the mold in the transport direction for supplying oil to the steel plate. Steel plate punching machine.

2. The mold has a first region for punching out rotor core pieces from the steel plate and a second region for punching out stator core pieces from the steel plate, wherein the first region is located upstream of the second region in the conveying direction. The oil supply unit is located between the first region and the second region. The steel plate punching apparatus according to claim 1.

3. The oil supply unit supplies the oil to the steel plate in a direction intersecting the conveying direction. The steel plate punching apparatus according to claim 1.

4. The oil supply unit has a plurality of nozzles, each having an oil discharge port formed at a predetermined interval. Multiple nozzles are arranged in the intersecting direction. The steel plate punching apparatus according to claim 3.

5. The oil supply unit supplies the oil to the steel plate in a mist form. The steel plate punching apparatus according to claim 1.

6. The oil supply unit is positioned at least above the steel plate being transported between the upper and lower molds. The steel plate punching apparatus according to claim 1.

7. The steel plate is conveyed intermittently in the conveying direction at predetermined distances. The oil supply unit supplies oil to the steel plate when the steel plate is being transported in the transport direction. The steel plate punching apparatus according to claim 1.

8. A step of supplying oil to the steel sheet supplied between the upper die and the lower die of a die having an upper die and a lower die for punching out a steel sheet, at least between the upstream end and the downstream end of the die in the direction of transporting the steel sheet. The process of sandwiching the steel plate between the upper die and the lower die and punching out the steel plate, The process includes stacking a plurality of punched steel plates, A method for manufacturing laminated steel sheets.

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