Method for manufacturing laminated iron core and apparatus for manufacturing laminated iron core

Abstract

To provide a laminated iron core manufacturing method and a laminated iron core manufacturing device capable of accurately obtaining lamination thickness of a laminated body during a lamination process in a press working device.SOLUTION: A laminated iron core manufacturing method includes: forming a laminated body by inserting a contour punch into a die with die holes for contour punching, punching a metal plate into a predetermined shape and repeatedly pressing it toward a cylinder located at the bottom of the die, a plurality of punching components punched from the metal plate are stacked in the die; acquiring a separation distance between the punch and the cylinder by a sensor when the punch reaches close to the bottom dead center in the process of punching the punching component from the metal plate; and calculating thickness of a plurality of punching components laminated in the die based on the separation distance obtained by the sensor.SELECTED DRAWING: Figure 9

Description

Technical Field

[0001] The present disclosure relates to a method for manufacturing a laminated core and a manufacturing apparatus for a laminated core.

Background Art

[0002] A laminated core is usually obtained by laminating a plurality of punched members in which a metal plate (for example, an electromagnetic steel sheet) is punched into a predetermined shape by a press working apparatus. Generally, the thickness of the metal plate is not completely uniform and varies slightly. This is referred to as "thickness deviation". Therefore, when a certain number of punched members are laminated to form a laminated core, a situation may occur in which the height of each obtained laminated core (also referred to as the "stacked thickness" of the laminated core) is different. Therefore, Patent Document 1 discloses a method of measuring the thickness of a metal plate conveyed to a press working apparatus with a sensor on the upstream side of the press working apparatus and adjusting the number of laminated punched members so that the stacked thickness of the obtained laminated core reaches a target value.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The present disclosure describes a method for manufacturing a laminated core and a manufacturing apparatus for a laminated core that can accurately obtain the stacked thickness of a laminate being laminated in a press working apparatus.

Means for Solving the Problems

[0005] An example of a method for manufacturing a laminated core includes repeatedly inserting a punch for blanking into a die provided with a die hole for blanking the outer shape, punching a metal plate into a predetermined shape with the punch, and pressing it toward a cylinder located below the die, thereby laminating a plurality of punched members punched from the metal plate in the die to form a laminate; obtaining, by a sensor, the separation distance between the punch and the cylinder when the punch reaches near the bottom dead center in the process of punching the punched member from the metal plate; and calculating the stack thickness of the plurality of punched members laminated in the die based on the separation distance obtained by the sensor.

[0006] An example of a manufacturing apparatus for a laminated core includes a die provided with a die hole for blanking configured to punch a metal plate into a predetermined shape, a punch for blanking configured to be insertable and removable with respect to the die hole, a cylinder disposed below the die, a sensor configured to obtain the separation distance between the punch and the cylinder, and a control unit. The control unit controls the punch to be inserted into the die, repeatedly punches the metal plate into a predetermined shape with the punch and presses it toward the cylinder, thereby laminating a plurality of punched members punched from the metal plate in the die to form a laminate, obtains, by the sensor, the separation distance between the punch and the cylinder when the punch reaches near the bottom dead center in the process of punching the punched member from the metal plate, and calculates the stack thickness of the plurality of punched members laminated in the die based on the separation distance obtained by the sensor.

Advantages of the Invention

[0007] According to the method for manufacturing a laminated core and the manufacturing apparatus for a laminated core according to the present disclosure, it is possible to accurately obtain the stack thickness of a laminate during the lamination process in a press working apparatus.

Brief Description of the Drawings

[0008] [Figure 1] FIG. 1(a) is a perspective view showing an example of a rotor laminated core, and FIG. 1(b) is a cross-sectional view taken along line B - B of FIG. 1(a). [Figure 2] Figure 2 is a schematic diagram showing an example of a manufacturing apparatus for rotor laminated cores. [Figure 3] Figure 3 is a schematic cross-sectional view showing an example of a press working apparatus. [Figure 4] Figure 4 is a schematic cross-sectional view showing an example of a fourth punching unit. [Figure 5] Figure 5 is a schematic cross-sectional view illustrating how multiple punched-out members are punched out from a metal sheet and stacked within a die. [Figure 6] Figure 6 is a schematic cross-sectional view illustrating how multiple punched-out components are punched out from a metal sheet and stacked within a die. [Figure 7] Figure 7 is a schematic cross-sectional view illustrating how multiple punched-out members are punched out from a metal sheet and stacked within a die. [Figure 8] Figure 8 is a schematic cross-sectional view illustrating how multiple punched-out components are punched out from a metal sheet and stacked within a die. [Figure 9] Figure 9 illustrates the time-dependent change in the distance acquired by the sensor. [Figure 10] Figure 10 is a magnified view of the vicinity of the local minimum in Figure 9. [Figure 11] Figure 11 is a schematic cross-sectional view showing another example of the fourth punching unit. [Modes for carrying out the invention]

[0009] In the following descriptions, the same reference numeral will be used for identical elements or elements with the same function, and redundant explanations will be omitted. Furthermore, in this specification, when referring to the top, bottom, right, and left of a figure, the direction of the reference numeral in the figure will be used as the reference.

[0010] [Configuration of the rotor laminated core] First, with reference to Figure 1, the configuration of a rotor laminated core 1, which is an example of a laminated core, will be described. The rotor laminated core 1 is part of the rotor. The rotor includes the rotor laminated core 1 and a shaft (not shown) attached to the rotor laminated core 1. The rotor may further include an end plate positioned on at least one end face of the rotor laminated core 1.

[0011] The rotor laminated core 1 comprises a laminated body 2 and a crimping portion 3. The laminated body 2 has a cylindrical shape. That is, a through hole 2a (central hole) extending along the central axis Ax is provided in the central part of the laminated body 2, as illustrated in Figure 1(a). A shaft can be placed inside the through hole 2a. Although not shown, a plurality of magnet insertion holes extending along the central axis Ax so as to penetrate the laminated body 2 may be provided in the laminated body 2.

[0012] The laminate 2 is constructed by stacking multiple punched members W. The punched members W are plate-like bodies formed by punching out a predetermined shape from a metal sheet (for example, an electrical steel sheet). The laminate 2 may also be constructed by a so-called roll stacking method, in which multiple punched members W are stacked while relatively shifting the angles between them. The angle of the roll stacking may be set to any size.

[0013] In the stacking direction of multiple punched members W (which is the height direction of the laminate 2 and also the vertical direction of the laminate 2), adjacent punched members W are fastened together by crimping portions 3. Specifically, as shown in Figure 1(b), the crimping portions 3 fasten together the punched members W that make up all but the bottom layer of the laminate 2. N The crimped 3a formed therein and the punched member W that forms the bottom layer of the laminate 2 B It has a through hole 3b formed in the crimp 3a, which is the punched member W N A recess formed on the surface side, and the punching member W N It is composed of a protrusion formed on the back side of the first punched member W N The recess of the crimp 3a is the punched member W N Other punched-out members W adjacent to the surface side N The protrusion of the crimp 3a is joined to the punched member W.N The convex portion of the caulking 3a of the one punching member W N is joined to the concave portion of the caulking 3a of another punching member W adjacent to it on the back side of the one punching member W N The through hole 3b is joined to the convex portion of the caulking 3a of the punching member W adjacent to the lowermost layer of the laminate 2. The through hole 3b has a function of preventing the punching member W formed subsequently from being fastened by the caulking 3a to the laminate 2 that has already been manufactured when the laminate 2 is continuously manufactured in the press processing apparatus 100 described later.

[0014] The plurality of punching members W may be fastened by various known methods instead of the caulking portion 3. For example, temporary caulking may be provided on the punching member W, and after obtaining a temporary laminate by fastening the plurality of punching members W through the temporary caulking, the laminate 2 may be obtained by removing the temporary caulking from the temporary laminate. Note that "temporary caulking" means caulking that is used to temporarily integrate a plurality of punching members W and is removed in the process of manufacturing the product (laminate 2).

[0015] [Manufacturing Apparatus for Rotor Laminated Core] Subsequently, referring to FIG. 2, the manufacturing apparatus 10 for the rotor laminated core will be described. The manufacturing apparatus 10 is configured to manufacture the rotor laminated core 1 from a strip-shaped metal plate MS. The manufacturing apparatus 10 includes an uncoiler 20, a feeding device 30, a press processing apparatus 100, a thickness measuring device 200 (measuring device), and a controller Ctr (control unit).

[0016] The uncoiler 20 is configured to rotatably hold the coil material 21. The coil material 21 is formed by winding the metal plate MS in a coil shape (spiral shape). The feeding device 30 includes a pair of rollers 31 and 32 that sandwich the metal plate MS from above and below. The pair of rollers 31 and so are configured to rotate and stop based on an instruction signal from the controller Ctr and intermittently and sequentially feed the metal plate MS toward the press processing apparatus 100.

[0017] ​​The press working device 100 is configured to operate based on an instruction signal from the controller Ctr. The press working device 100 is configured to sequentially perform bending or punching operations on a metal plate MS fed out by a feeding device 30 using a plurality of punches and dies to form a plurality of punched members W. The press working device 100 may be configured to sequentially stack the plurality of punched members W obtained by punching to form a stacked body 2. The stacked body 2 formed by the press working device 100 may be conveyed to the lamination thickness measuring device 200 by a conveyor Cv, for example, or may be conveyed to the lamination thickness measuring device 200 manually. Details of the press working device 100 will be described later.

[0018] The lamination thickness measuring device 200 is configured to operate based on an instruction signal from the controller Ctr and measure the lamination thickness (height of the stacked body 2) of the stacked body 2. The lamination thickness measuring device 200 measures the lamination thickness of the stacked body 2 in a state where a predetermined load L is applied to the stacked body 2 from the lamination direction. The load L can be of various sizes depending on the size of the stacked body 2. For example, the height H of the stacked body 2 after pressurization may be such that it satisfies 0.999H0 ≤ H < H0, where H0 is the thickness of the stacked body 2 before pressurization and is 99.9% or more of the thickness H0 before pressurization.

[0019] The lamination thickness measuring device 200 includes a pair of clamping members 201, 202, a lifting mechanism 203, and a distance sensor 204. The pair of clamping members 201, 202 may be, for example, flat plates having a rectangular shape. The pair of clamping members 201, 202 are positioned so as to be arranged in the vertical direction. A guide shaft configured to guide the clamping member 202 in the vertical direction may be provided on the upper surface of the clamping member 201 located on the lower side.

[0020] The lifting mechanism 203 is connected to the clamping member 202. The lifting mechanism 203 operates based on an instruction from the controller Ctr and is configured to reciprocate the clamping member 202 in the vertical direction. The lifting mechanism 203 is not particularly limited as long as it moves the clamping member 202 up and down, and may be, for example, an actuator, an air cylinder, or the like.

[0021] The distance sensor 204 is configured to measure the separation distance between the clamping member 201 and the clamping member 202. When the clamping members 201 and 202 are clamping the laminate 2, the distance sensor 204 measures the separation distance, thereby indirectly measuring the thickness of the laminate 2. The distance sensor 204 may be provided, for example, on the clamping member 202. The data on the thickness of the laminate 2 measured by the distance sensor 204 is transmitted to the controller Ctr.

[0022] The controller Ctr is configured to generate signals to operate the dispensing device 30, the press working device 100, the stacking thickness measuring device 200, and the conveyor Cv, based on, for example, a program recorded on a recording medium (not shown) or operation input from an operator. The controller Ctr is configured to transmit these signals to the dispensing device 30, the press working device 100, the stacking thickness measuring device 200, and the conveyor Cv, respectively.

[0023] [Details of the press working equipment] Next, the details of the press working apparatus 100 will be described with reference to Figures 3 and 4. The press working apparatus 100 includes a lower die 110, an upper die 120, and a press machine 130, as shown in Figure 3. The lower die 110 may include a base 111, a die holder 112, a die plate 113, and a plurality of guide posts 114.

[0024] The base 111 is fixed, for example, on the floor and functions as the base for the entire press working apparatus 100. The die holder 112 is supported on the base 111. The die holder 112 has a plurality of discharge holes C1 to C4 and a recess C5 that accommodates a squeeze ring E, which will be described later. The discharge holes C1 to C4 may extend vertically inside the die holder 112. Material punched out from the metal plate MS (e.g., punched member W, waste material, etc.) is discharged through the discharge holes C1 to C4.

[0025] The die plate 113 is mounted on the die holder 112. The die plate 113 includes multiple dies D1 to D4. Each die D1 to D4 is positioned to correspond to a punch P1 to P4 and includes a die hole through which the corresponding punch P1 to P4 can be inserted. The dies D1 to D4 are arranged in this order from upstream to downstream in the direction of transport of the metal plate MS.

[0026] Die D1, together with punch P1, constitutes a first punching unit for punching out a metal sheet MS. The metal pieces punched out of the metal sheet MS by the first punching unit are discharged to the outside of the press working device 100 through discharge hole C1. Die D2, together with punch P2, constitutes a second punching unit for selectively punching out a metal sheet MS. The metal pieces punched out of the metal sheet MS by the second punching unit are discharged to the outside of the press working device 100 through discharge hole C2.

[0027] Die D3, together with punch P3, constitutes a third punching unit for press working (e.g., cutting, bending, or partial punching) of the metal sheet MS. Die D4, together with punch P4, constitutes a fourth punching unit for punching the metal sheet MS. The punched members W punched out from the metal sheet MS by the fourth punching unit are discharged to the outside of the press working device 100 through the discharge hole C4. Details of the fourth punching unit will be described later.

[0028] Multiple guide posts 114 extend linearly upward from the die holder 112. Together with the guide bush 121a (described later), the multiple guide posts 114 are configured to guide the upper die 120 in the vertical direction. Alternatively, the multiple guide posts 114 may be attached to the upper die 120 so as to extend downward from it.

[0029] The upper die 120 includes a punch holder 121, a stripper 122, a plurality of punches P1 to P4, and a switching device 123. The upper die 120 may further include pilot pins (not shown) for positioning the metal sheet MS during punching.

[0030] The punch holder 121 is positioned above the die holder 112 and the die plate 113, facing them. The punch holder 121 is configured to hold a plurality of punches P1 to P4. The plurality of punches P1 to P4 held in the punch holder 121 protrude downward from the lower surface of the punch holder 121.

[0031] The punch holder 121 is provided with a plurality of cylindrical guide bushes 121a. Each of the guide bushes 121a is positioned to correspond to a plurality of guide posts 114. Each guide post 114 can be inserted through the corresponding guide bush 121a. If the guide posts 114 are attached to the upper die 120, the guide bushes 121a may be provided on the lower die 110.

[0032] The stripper 122 is configured to remove the metal sheet MS that has become stuck to the punches P1 to P4 when the punches P1 to P4 are press-formed. The stripper 122 is positioned between the dies D1 to D4 and the punch holder 121.

[0033] The stripper 122 is connected to the punch holder 121 via a connecting member 124. The upper part of the connecting member 124 is inserted into an insertion hole 121b provided in the punch holder 121. Therefore, the connecting member 124 is configured to be vertically movable relative to the punch holder 121. The lower part of the connecting member 124 is fixed to the stripper 122. Therefore, the stripper 122 is suspended and held by the punch holder 121 via the connecting member 124 so that it can move vertically relative to the punch holder 121. A biasing member 125 (for example, a compression coil spring) may be attached around the main body of the connecting member 124, configured to act on the punch holder 121 and the stripper 122 with a biasing force in a direction that separates them.

[0034] The stripper 122 has through holes at positions corresponding to punches P1 to P4. Each through hole extends vertically and, when viewed from above, overlaps with the die holes of the corresponding dies D1 to D4. The lower parts of punches P1 to P4 are inserted into each through hole. The lower parts of punches P1 to P4 are slidable within each through hole.

[0035] The punches P1 to P4 are arranged in this order from the upstream side to the downstream side of the press working apparatus 100. The lower end of punch P1 has a shape corresponding to the die hole of die D1. The first punching unit, composed of punch P1 and die D1, may form through holes in the metal plate MS that correspond to the through holes 2a of the laminate 2.

[0036] The lower end of the punch P2 has a shape corresponding to the die hole of the die D2. The second punching unit, composed of the punch P2 and the die D2, may selectively form a through hole in the metal plate MS that corresponds to the through hole 3b of the crimping portion 3. Switching between forming or not forming such a through hole in the metal plate MS is performed by a switching device 123, which will be described later.

[0037] The lower end of the punch P3 has a shape corresponding to the die hole of the die D3. The third punching unit, composed of the punch P3 and the die D3, may form irregularities on the metal plate MS corresponding to the crimping 3a of the crimping portion 3. However, if a through hole is formed in the metal plate MS by the second punching unit, the tip of the punch P3 passes through the through hole, so no irregularities corresponding to the crimping 3a are formed on the metal plate MS.

[0038] The lower end of the punch P4 has a shape corresponding to the die hole of the die D4. The fourth punching unit, composed of the punch P4 and the die D4, may punch a metal plate MS into a predetermined shape to form a punched member W (also called "outer shape punching").

[0039] The switching device 123 may be located above the punch P2 and inside the punch holder 121. If the press working apparatus 100 includes multiple punches P2, the same number of switching devices 123 as the number of punches P2 may be located above each punch P2 to correspond to each individual punch P2.

[0040] The switching device 123 is, for example, a cam mechanism and includes a cam member 123a and an actuator 123b. The cam member 123a is configured to slide horizontally. The lower surface of the cam member 123a is provided with a recess 123c that is recessed upward. The recess 123c is configured to accommodate the head of the punch P2.

[0041] The actuator 123b is configured to drive the cam member 123a horizontally based on an instruction signal from the controller Ctr. The actuator 123b may be configured to move the cam member 123a between, for example, a first position in which the head of the punch P2 is located outside the recess 123c and in contact with the lower surface of the cam member 123a, and a second position in which the head of the punch P2 is housed inside the recess 123c. The actuator 123b may be located outside the upper die 120 rather than inside the punch holder 121.

[0042] The press machine 130 is configured to move the upper die 120 up and down based on instructions from the controller Ctr. The press machine 130 includes a crankshaft 131 connected to the punch holder 121 and a drive mechanism 132 configured to rotate the main shaft of the crankshaft 131. When the main shaft of the crankshaft 131 is rotated by the drive mechanism 132, the eccentric axis of the crankshaft 131 moves in a circular motion around the main shaft. Consequently, the punch holder 121 reciprocates up and down between the top dead center and the bottom dead center.

[0043] Here, the configuration of the fourth punching unit described above will be explained in more detail with reference to Figure 4. The die D4 may be placed on a squeeze ring E housed in a recess C5 of the die holder 112, or it may be positioned above the squeeze ring E at a distance from it. The die hole of the die D4 communicates with a through hole provided in the squeeze ring E. When viewed from above, the outer shape of the die hole of the die D4 and the outer shape of the through hole of the squeeze ring E may be substantially the same as the outer shape of the punching member W.

[0044] The outer diameter of the through-hole in the squeeze ring E may be set to be slightly smaller than the outer diameter of the die hole in the die D4. In this case, when the punched member W punched out by the die D4 passes through the die D4 and reaches the squeeze ring E, a lateral pressure acts on the punched member W from the outer circumference toward the inside. As a result, the punched member W is held in place by the squeeze ring E and is less likely to fall downward, so that fastening between it and subsequent punched members W via the crimping portion 3 becomes more reliable. That is, within the squeeze ring E, a predetermined number of punched members W are fastened together by the crimping portion 3 to form a laminate 2.

[0045] A drive mechanism 141, a cylinder 142, and a pusher 143 are arranged inside the discharge port C4. The drive mechanism 141 is configured to drive the cylinder 142 in the vertical direction based on instruction signals from the controller Ctr.

[0046] The cylinder 142 is located below the die D4 and the squeeze ring E. The cylinder 142 is configured to elastically support the punched member W that is punched out of the metal plate MS by the punch P4 and exposed below the squeeze ring E. This prevents the punched member W from falling. That is, the cylinder 142 may include a buffering mechanism that supports the cylinder body at a predetermined pressure to mitigate the impact force from the punch P4 when punching out the metal plate MS. The cylinder 142 may be, for example, a hydraulic cylinder.

[0047] The cylinder 142 may be driven by a drive mechanism 141 so as to intermittently move downward each time the punching member W is punched out from the metal plate MS by the punch P4 while the punching member W is placed on the cylinder 142. The outer shape of the cylinder 142 may be set to be larger than the outer shape of the through hole of the squeeze ring E. That is, the cylinder 142 may be configured so that its tip does not enter the through hole of the squeeze ring E.

[0048] The pusher 143 is configured to discharge the stacked material 2 on the cylinder 142 onto the conveyor Cv based on an instruction signal from the controller Ctr. The stacked material 2 discharged onto the conveyor Cv is transported to the stack thickness measuring device 200, where its stack thickness is measured.

[0049] The lower end (tip) of the punch P4 is provided with a recess P4a that curves toward the upper end (base) of the punch P4. When viewed from below, the recess P4a may be located in the central part of the punch P4. A sensor SE is mounted inside the recess P4a via a heat sink 151 (heat dissipation mechanism).

[0050] The sensor SE is configured to measure the distance between the lower end surface of the punch P4 and the upper end surface of the cylinder 142 (hereinafter simply referred to as "distance"). The distance data measured by the sensor SE is transmitted to the controller Ctr.

[0051] The sensor SE may be, for example, a laser displacement meter. In this case, the light-emitting and light-receiving parts of the sensor SE may be positioned at approximately the same height as the lower end surface of the punch P4. Alternatively, if the light-emitting and light-receiving parts of the sensor SE are located inside the recess P4a below the lower end surface of the punch P4, the controller Ctr may perform a process to subtract the difference between the light-emitting and light-receiving parts of the sensor SE and the lower end surface of the punch P4 from the measurement result to obtain the separation distance.

[0052] The heat sink 151 is positioned around the sensor SE so as to sandwich the sensor SE. The heat sink 151 may be made of a material with a higher thermal conductivity than the sensor SE (for example, a metal plate).

[0053] [Manufacturing method for rotor laminated iron core] Next, the manufacturing method of the rotor laminated core 1 will be explained with reference to Figures 2 to 4.

[0054] First, as shown in Figures 2 and 3, the metal sheet MS is intermittently fed to the press working device 100 by the feeding device 30. When a predetermined portion of the metal sheet MS reaches the first processing unit, the press machine 130 operates and pushes the upper die 120 downward toward the lower die 110. Even after the stripper 122 reaches the metal sheet MS and the metal sheet MS is held between the stripper 122 and the die plate 113, the press machine 130 continues to push the upper die 120 downward.

[0055] At this time, the stripper 122 does not move, but the punch holder 121 and punches P1 to P4 continue to descend. As a result, the tip of punch P1 moves downward through each through hole of the stripper 122 and further reaches the vicinity of the die hole of die D1. In this process, punch P1 punches out the metal plate MS along the die hole of die D1. This creates through holes in the metal plate MS corresponding to the through holes 2a of the laminate 2. The waste material punched out from the metal plate MS is discharged from the discharge hole C1. After that, the press machine 130 operates and raises the upper die 120.

[0056] Next, the metal plate MS is intermittently fed by the feeding device 30, and when a predetermined portion of the metal plate MS reaches the second processing unit, the upper die 120 moves up and down by the press machine 130, as described above. At this time, if the cam member 123a of the switching device 123 is in the first position by the actuator 123b, the lower end of the punch P2 protrudes below the lower surface of the stripper 122. As a result, the punch P2 punches through the metal plate MS along the die hole of the die D2. This forms a through hole in the metal plate MS corresponding to the through hole 3b of the crimping portion 3. The waste material punched out from the metal plate MS is discharged from the discharge hole C2. On the other hand, if the cam member 123a of the switching device 123 is in the second position by the actuator 123b, the lower end of the punch P2 does not protrude below the lower surface of the stripper 122. As a result, the metal plate MS is not punched out by the punch P2. After that, the press machine 130 operates and raises the upper die 120.

[0057] Next, the metal sheet MS is intermittently fed by the feeding device 30, and when a predetermined portion of the metal sheet MS reaches the third processing unit, the upper die 120 moves up and down by the press machine 130, as described above. At this time, if a through hole is formed in the metal sheet MS in the second processing unit, the lower end of the punch P3 passes through the through hole. Therefore, the metal sheet MS is not punched out by the punch P3. On the other hand, if a through hole is not formed in the metal sheet MS in the second processing unit, the punch P3 press-processes the metal sheet MS (for example, cutting and bending, half-punching, etc.). As a result, irregularities corresponding to the crimp 3a of the crimping portion 3 are formed on the metal sheet MS.

[0058] Next, the metal sheet MS is intermittently fed by the feeding device 30, and when a predetermined portion of the metal sheet MS reaches the fourth processing unit, the upper die 120 moves up and down by the press machine 130, as described above. In this process, the punch P4 punches out the metal sheet MS along the die hole of the die D4. This forms a punched member W with a through hole corresponding to the through hole 2a of the laminate 2 and a crimped portion 3 (crimp 3a or through hole 3b). The sensor SE continuously measures the separation distance during the operation of the press processing device 100 and transmits the measured data to the controller Ctr.

[0059] Here, as shown in Figure 4, the punched members W punched out from the metal plate MS are stacked with the previously punched members W within the die hole of the die D4 and fastened together by the crimping portion 3. At this time, in order to stack the punched members W, a drive device (not shown) may rotate the die D4 and the squeeze ring E by a predetermined angle before punching out the punched members W.

[0060] The above process is repeated until a predetermined number of punched members W are stacked in the die D4 and squeeze ring E, forming a laminate 2. The laminate 2 is discharged onto the conveyor Cv by the pusher 143 and transported to the stacking thickness measuring device 200. When the stacking thickness of the laminate 2 is measured in the stacking thickness measuring device 200, the data of the stacking thickness is transmitted to the controller Ctr. After that, other processes (for example, attachment of permanent magnets, attachment of end plates, welding, attachment of rotating shafts, etc.) are performed on the laminate 2, and the rotor laminate core 1 is completed.

[0061] [Details of the layer formation process] Next, referring to Figures 5 to 9, the process of forming the laminate 2 by the press working apparatus 100 will be explained in more detail, starting from the initial state (see Figure 5(a)) in which no punching member W is present in the die D4 and squeeze ring E.

[0062] First, the punch P4 and die D4 punch out the first punched member W(W B When the punched member W(W) is punched out from the metal plate MS,B The first punched member W(W) is held on the inner circumferential surface of die D4 or squeeze ring E. B ) has a through hole formed in it that corresponds to the through hole 3b of the crimping part 3. At this time, the punching member W(W B ) does not reach cylinder 142.

[0063] Next, the punch P4 and die D4 punch out the subsequent punched member W(W N When the punched member W(W) is punched out from the metal plate MS, N ) is the punched-out member W(W B ) are held on the inner circumferential surface of the die D4 and squeeze ring E while being mutually connected via the crimping portion 3 (see Figure 5(b)). These subsequent punching members W(W N ) has irregularities formed on it that correspond to the crimping 3a of the crimping part 3. In this case as well, the punched member W (W) located at the bottom end B ) does not reach cylinder 142.

[0064] Thus, during the predetermined period (initial punching period) from the initial state until a predetermined number of punched members W are formed by the press working device 100, the stacking thickness of the multiple punched members W within the die D4 and squeeze ring E cannot be measured using the sensor SE. Therefore, the value obtained by dividing the target stacking thickness Z of the laminate 2 by the approximate thickness t of the metal plate MS is used as the provisional number of punches N (N is a natural number) required to obtain one laminate 2. Note that the "approximate thickness t" here may be, for example, the measured thickness at any one point on the metal plate MS, or it may be the average of the measured thicknesses at any multiple points on the metal plate MS.

[0065] Next, before the Nth punched-out member W is stacked, the N+1th punched-out member W(W) of the metal plate MS is stacked. BThe controller Ctr controls the switching device 123 to position the cam member 123a in the first position so that a through hole corresponding to the through hole 3b of the crimping portion 3 is formed in the region that will become the Nth punched member W. B In the region where the crimping portion 3 is located, through holes corresponding to the through holes 3b of the crimping portion 3 are pre-formed by the punch P2 and die D2. Then, when N punched members W are stacked, the first stack 2 is formed inside the die D4 and squeeze ring E (see Figure 5(b)). Hereinafter, the first stack 2 will be referred to as "stack 21", and similarly, the Nth stack 2 will be referred to as "stack 2 N It is sometimes referred to as "..."

[0066] Following this, punching member W(W) containing a through hole corresponding to through hole 3b B The punched-out member W(W) of the uppermost layer constituting the laminate 21 is punched out and stacked on top of the laminate 21 (see Figure 5(b)). N ) and the bottommost punched member W(W) that constitutes the laminate 22. B ) and are not fastened together by the crimping portion 3, and the two remain separated (see also).

[0067] Next, the controller Ctr controls the switching device 123 to position the cam member 123a in the second position. Then, the punched member W(W) of the bottom layer constituting the laminate 22 is moved. B ) followed by multiple punched members W(W N ) are stacked (see Figure 6(a)). In the example shown herein, within the die D4 and squeeze ring E, when a predetermined number of punching members W constituting the subsequent laminate 2 are stacked on top of the preceding laminate 2, the bottom layer of punching members W (W) constituting the preceding laminate 2 is stacked. BThe cylinder reaches the cylinder 142. As a result, the preceding laminate 2 and the multiple punched members W laminated on top of it are supported by the cylinder 142. From this point onward, each time a punched member W is punched out, the cylinder 142 descends intermittently by the thickness of the punched member W. Therefore, the separation distance measured by the sensor SE gradually increases, as illustrated in Figure 9.

[0068] Since the punch P4 moves up and down at a nearly constant frequency, the separation distance measured by the sensor SE fluctuates approximately periodically, taking on minimum and maximum values ​​like a sine wave, as shown in Figure 9. The minimum value in Figure 9 is the value when the punch P4 reaches near its bottom dead center. Note that a slight displacement may occur in the punch P4 or cylinder 142 at the bottom dead center of the punch P4, so the minimum value may not occur at the bottom dead center of the punch P4.

[0069] Here, an example of a case where the punch P4 does not take a minimum value at its bottom dead center will be explained with reference to Figure 10. First, as the punch P4 descends, it punches out the punched member W from the metal plate MS, and the punch P4 comes closest to the cylinder 142, causing the first minimum value Q1 to appear. Subsequently, the impact of the punch P4 punching out the punched member W pushes down the cylinder 142, and the cylinder 142 is elastically displaced downward, increasing the separation distance. Along the way, the punch P4 actually reaches its bottom dead center Q2. After that, as the cylinder 142 moves further away from the punch P4, the elastic force causes the cylinder 142 to approach the punch P4 again, causing the second minimum value Q3 to appear. At this point, the punch P4 has started to rise, so the separation distance increases rapidly thereafter.

[0070] Multiple punched members W within die D4 and squeeze ring E are clamped between punch P4 and cylinder 142 when punch P4 reaches near bottom dead center. At this time, the load applied to the multiple punched members W by punch P4 and cylinder 142 causes the crimped portions 3 of the multiple punched members W to be more firmly fastened to each other. In other words, the minimum value of the separation distance measured by sensor SE represents the stacked thickness of all punched members W present in die D4 and squeeze ring E at the time of measurement by sensor SE (hereinafter, this stacked thickness will be referred to as "total stacked thickness X"). In other words, the difference value δ (see Figure 9) between the total stacked thickness X at a certain point in time and the total stacked thickness X at the previous point in time represents the plate thickness of a single punched member W. For example, the difference value δ between the total stacked thickness X when the M (M is a natural number of 2 or more) punched member W is punched and the total stacked thickness X when the M-1 punched member W is punched. M This will indicate the thickness of the M-th punched-out member W.

[0071] Next, before the 2Nth punched member W is stacked, the 2N+1th punched member W(W) of the metal plate MS is stacked. B The controller Ctr controls the switching device 123 to position the cam member 123a in the first position so that a through hole corresponding to the through hole 3b of the crimping portion 3 is formed in the region that will become the 2Nth punched member W. B In the region that will be ), through holes corresponding to the through holes 3b of the crimping portion 3 are pre-formed by the punch P2 and die D2. Then, 2N punched members W(W N When the layers are stacked, a stack 22 is formed on top of the stack 21 within the die D4 and squeeze ring E (see Figure 6(b)). The controller Ctr sets the total thickness X at this time (i.e., the sum of the stacks 21 and 22) to a reference value X T Remember it as such.

[0072] Following this, punching member W(W) containing a through hole corresponding to through hole 3bB The punched-out member W(W) of the uppermost layer constituting the laminate 22 is punched out and stacked on top of the laminate 22 (see Figure 7(a)). N ) and the bottommost punched member W(W) that constitutes the laminate 23. B ) and are not fastened together by the crimping portion 3, and the two remain separated (see also).

[0073] Next, the controller Ctr controls the switching device 123 to position the cam member 123a in the second position. Then, the punched member W(W) of the bottom layer constituting the laminate 23 is moved. B ) followed by multiple punched members W(W B These are stacked (see Figure 7(a)).

[0074] Here, the stacking thickness of the multiple punched members W constituting the laminate 23 at a certain point in time is calculated by subtracting the reference value X from the total stacking thickness X. T It may also be calculated by subtracting. Hereinafter, the stacking thickness of the multiple punched members W constituting the laminate 23 at a certain point in time will simply be referred to as "stacking thickness t3", and similarly, the laminate 2 N The stacking thickness of multiple punched members W at a certain point in time is simply referred to as "stacking thickness t". N It is sometimes referred to as "the stacked thickness T". On the other hand, the stacking thickness of the laminate 2 itself is sometimes referred to as "stacked thickness T".

[0075] The stacking thickness t3 is, for example, the difference value δ2, δ3, ..., δ obtained from the present to the past when the Mth punched member W constituting the laminate 23 is punched out at this point in time. M-1 ,δ M The value may be obtained by sequentially adding these values. That is, the stack thickness t3 is δ2 + δ3 + ... + δ M-1 +δ M It may also be calculated by the following method: Stack thickness t N The same calculation may also be used.

[0076] The stacking thickness t3 may be a value calculated based on, for example, the following three parameters. • The total stack thickness X when laminates 21 and 22 are present in die D4 and squeeze ring E (i.e., the sum of the stack thicknesses T1 and T2 of laminates 21 and 22, and hereafter referred to as "total stack thickness X") A (It is called "...") When the laminate 22 and multiple punched members W constituting the laminate 23 are present in die D4 and squeeze ring E, the total stack thickness X (hereinafter referred to as "total stack thickness X") B (It is called "...") The stack thickness (hereinafter referred to as "stack thickness Y") of the laminated body 21 discharged from the press working machine 100 is measured by the stack thickness measuring device 200. Specifically, total thickness X A By subtracting the stacking thickness Y from the total stacking thickness X, we obtain the stacking thickness T2, so the total stacking thickness X B The stacking thickness t3 can also be obtained by subtracting the stacking thickness T2 from the following. Similarly, for stacks 24, 25, ..., 2 N-1 ,2 N The thickness of the stack before completion is t4, t5, ..., t N-1 ,t N You may also calculate each of them separately.

[0077] Furthermore, if the laminate 21 is discharged from the press working device 100 after the completion of the laminate 23, the stacking thickness t4 may be calculated based on the following parameters in addition to the three parameters mentioned above. • The total stack thickness X when laminates 22 and 23 are present in die D4 and squeeze ring E (i.e., the sum of the stack thicknesses T2 and T3 of laminates 22 and 23, and hereafter referred to as "total stack thickness X") C (It is called "...") When the laminate 23 and multiple punched members W constituting the laminate 24 are present in die D4 and squeeze ring E, the total stack thickness X (hereinafter referred to as "total stack thickness X") D (It is called "...") Specifically, total thickness X A Subtracting the stacking thickness Y from this gives the stacking thickness T2, and the total stacking thickness X C By subtracting the stacking thickness T2 from this, the stacking thickness T3 is obtained, so the total stacking thickness X D The stacking thickness t4 can also be obtained by subtracting the stacking thickness T3 from the total stacking thickness t4.

[0078] The determination of whether the accumulated thickness t3 has reached the target accumulated thickness Z may be performed as follows. For example, when the accumulated thickness t3 is larger than the value (T - t) obtained by subtracting the approximate plate thickness t from the target accumulated thickness Z and satisfies Z - t < T3 ≤ Z, it may be determined that the accumulated thickness t3 has reached the target accumulated thickness Z.

[0079] Alternatively, based on the amount of change over time α of the total accumulated thickness X during a predetermined period, it may be predicted when the accumulated thickness t3 reaches the target accumulated thickness Z. Here, the amount of change over time α means an approximate line of a plurality of total accumulated thicknesses X acquired before and including the current time. There is no particular limitation on the type of the approximate line. For example, it may be a moving average line using data of a plurality of total accumulated thicknesses X before and including the current time, a first-order approximate line, or a polynomial approximate line. When the amount of change over time α is obtained, since the period of the up-and-down movement of the punch P4 is substantially constant (that is, the time interval of the minimum value is substantially constant), the number of minimum values until the amount of change over time α exceeds the target accumulated thickness Z after the current time can be obtained. In the example shown in FIG. 9, the number of minimum values until the amount of change over time α exceeds the target accumulated thickness Z after the current point G1 is three. Therefore, by punching the metal plate MS three more times with the punch P4, a laminate 23 having an accumulated thickness extremely close to the target accumulated thickness Z can be obtained. The amount of change over time α may be calculated each time the minimum value of the separation distance (total accumulated thickness X) is acquired by the sensor SE.

[0080] Note that, as shown by the point G2 in FIG. 9, a large error may occur in the minimum value of the separation distance measured by the sensor SE due to the influence of disturbance. In such a case, the minimum value (total accumulated thickness X) at the point G2 may be excluded. Specifically, the difference between the amount of change over time α when the minimum value immediately before the point G2 is acquired by the sensor SE and the minimum value at the point G2 is calculated, and if the difference is within a predetermined range, the minimum value at the point G2 is not excluded, and if the difference is outside the predetermined range, the minimum value at the point G2 is excluded. When the minimum value at the point G2 is excluded, the amount of change over time α at that time may be adopted as the total accumulated thickness X instead of the minimum value.

[0081] Here, just before the stacking thickness t3 reaches the target stacking thickness Z, several punched members W(W) B The controller Ctr controls the switching device 123 to position the cam member 123a in the first position so that a through hole corresponding to the through hole 3b of the crimping portion 3 is formed in the two punching members W(W). In the example of this specification, since the second punching unit is located upstream of the fourth punching unit and two processes earlier, when the number of predicted sheets for which the stacking thickness t3 will reach the target stacking thickness Z is 2, a through hole corresponding to the through hole 3b of the crimping portion 3 is formed in a predetermined area upstream of the metal sheet MS. Thereafter, the two punching members W(W) N When the layers are stacked, a stack 23 is formed on top of the stack 22 within the die D4 and squeeze ring E (see Figure 7(b)).

[0082] As described above, the laminate 23 is completed when it is determined that the stacking thickness t3 has reached the target stacking thickness Z, based on the separation distance acquired by the sensor SE. Therefore, the number of punched members W constituting the laminate 23 changes according to the actual plate thickness of the punched members W. Thus, unlike laminates 21 and 22 which are constructed by stacking N punched members W, the number of punched members W constituting the laminate 23 may increase or decrease from N.

[0083] Once the laminate 23 is completed, as illustrated in Figure 7(b), the laminate 21 is discharged from the die D4 and squeeze ring E and supported by the cylinder 142. In this state, by lowering the cylinder 142 to a predetermined height, the laminate 21 that is not held by the die D4 and squeeze ring E is discharged onto the conveyor Cv by the pusher 143 and transported to the stack thickness measuring device 200 (see Figure 8(a)). Subsequently, the cylinder 142 rises again, and the laminates 22 and 23 that are held by the die D4 and squeeze ring E are once again supported by the cylinder 142 (see Figure 8(b)).

[0084] From this point onward, the fourth and subsequent layers 2 are formed in the same manner as the third layer 23. That is, the fourth and subsequent layers 2 N Also, based on the separation distance obtained by the sensor SE, the stacking thickness tN The process is completed when it is determined that the target stacking thickness Z has been reached. Although the laminates 21 and 22 are constructed by stacking N punched members W, respectively, without regard to the separation distance acquired by the sensor SE, the laminates 21 and 22 may also be used as products if their stacking thickness reaches the target stacking thickness Z.

[0085] [Effect] As shown in the above example, the separation distance acquired by the sensor SE is the stacked thickness of the multiple punched members W under pressure from the punch P4 and cylinder 142. Therefore, even if there is a thickness deviation in the metal plate MS, the pressure from the punch P4 and cylinder 142 makes it easier for the multiple punched members W to come into close contact, and the gaps between the multiple punched members W are greatly reduced, allowing the stacked thickness to be acquired while the multiple punched members W are stacked. Thus, it becomes possible to acquire the stacked thickness of the laminated body 2 in the process of being stacked within the press working apparatus 100 with high accuracy.

[0086] As shown in the above example, the sensor SE is located inside the punch P4. Therefore, there is no need to significantly modify the press working apparatus 100 in order to attach the sensor SE to the press working apparatus 100. Consequently, it is possible to attach the sensor to an existing press working apparatus 100 simply and inexpensively.

[0087] Based on the above examples, the thickness t is determined based on the time change α. N The number of layers predicted to reach the target stacking thickness Z is calculated. Therefore, it becomes possible to more accurately determine the timing of forming through holes in the punched members W that will make up the next laminate 2 to be manufactured, before the currently manufactured laminate 2 is completed.

[0088] As shown in the above example, if a large error occurs in the minimum value of the separation distance measured by the sensor SE due to the influence of disturbances, that minimum value is excluded. Therefore, the time change amount α can be obtained with higher accuracy. Consequently, it becomes possible to determine with even greater accuracy the timing of forming through holes in the punched member W that constitutes the next laminate 2 to be manufactured.

[0089] As shown in the above example, the time-varying quantity α can be the moving average of the separation distance acquired by the sensor SE over a predetermined period. In this case, even if there are large fluctuations or errors in the data of the separation distance, their effects are reduced. Therefore, by using the moving average as the time-varying quantity α, it becomes possible to calculate the number of punches for the metal plate MS more accurately.

[0090] As shown in the above example, the stacked thickness of the multiple punched members W present in the die D4 and squeeze ring E at the time of measurement by the sensor SE can be a value obtained by sequentially adding the difference values ​​δ obtained from the present to the past. In this case, the stacked thickness of the multiple punched members W can be calculated using an extremely simple method.

[0091] As shown in the above example, the stacking thickness of one stacked body 2 within the die D4 and squeeze ring E can be calculated based on the separation distance between the two stacked bodies 2 within the die D4 and squeeze ring E acquired by the sensor SE, and the stacking thickness of one already completed stacked body 2 measured by the stacking thickness measuring device 200. In this case, the stacking thickness of one already completed stacked body 2 is measured more accurately by the stacking thickness measuring device 200. Therefore, by using the measurement value from the stacking thickness measuring device 200 and the separation distance acquired by the sensor SE, it becomes possible to acquire the stacking thickness of stacked bodies in the process of being stacked within the press working apparatus 100 with higher accuracy.

[0092] In the above example, the sensor SE is installed inside the punch P4 via the heat sink 151. Therefore, the heat generated in the sensor SE during operation is dissipated via the heat sink 151. Consequently, temperature drift associated with temperature changes in the sensor SE is reduced. As a result, it becomes possible to obtain the stacking thickness of the laminate 2 in the process of being stacked inside the press working apparatus 100 with higher accuracy.

[0093] [Differentiation] The disclosures herein should be considered in all respects to be illustrative and not restrictive. Various omissions, substitutions, and modifications may be made to the above examples without departing from the claims and the gist thereof.

[0094] (1) The present disclosure may also be applied to a so-called "joint cutting process" in which a punched member that will become the stator laminated core and a punched member that will become the rotor laminated core are formed from the same metal sheet MS. In joint cutting, after the punched member that will become the rotor laminated core is punched out from the metal sheet MS, the punched member that will become the stator laminated core is punched out from the metal sheet MS so as to surround the area in which the punched member has been punched out.

[0095] (2) In place of the heat sink 151, other heat dissipation mechanisms may be used to dissipate heat from the sensor SE. For example, a cooling mechanism that circulates a cooling medium (e.g., air, water, etc.) around the sensor SE may be used, or a blowing mechanism that blows air onto the sensor SE may be used. Alternatively, the sensor SE may be provided inside the punch P4 without a heat dissipation mechanism.

[0096] (3) As illustrated in Figure 11, the upper end (tip) of the cylinder 142 may be provided with a recess 142a that is recessed toward the lower end (base) of the cylinder 142. When viewed from above, the recess 142a may be located in the central part of the cylinder 142. A sensor SE may be placed inside the recess 142a. In this case as well, the sensor SE can measure the distance between the lower end surface of the punch P4 and the upper end surface of the cylinder 142.

[0097] (4) The sensor SE may be located outside the punch P4 or the cylinder 142 if it is possible to measure the distance between the lower end surface of the punch P4 and the upper end surface of the cylinder 142 near the bottom dead center of the punch P4. For example, the sensor SE may be provided on the outer surface of the punch P4 or on the outer surface of the cylinder 142.

[0098] (5) Even if a large error occurs in the minimum value of the separation distance measured by the sensor SE, the time change α may be calculated without excluding the minimum value.

[0099] (6) Multiple punched members W may be joined to each other by, for example, an adhesive. In this case, a metal plate MS with adhesive applied to a predetermined portion may be punched out using a punch P4 and a die D4, and the punched members W formed by the punching out may be bonded to already punched members W while being laminated. When multiple punched members W are joined to each other by an adhesive, variations may occur in the thickness of the adhesive layer placed between the punched members W depending on the flow of the adhesive. As a result, it has been difficult to control the stacking thickness of the laminate 2, but by applying the technology of this disclosure, it is possible to obtain the stacking thickness of the laminate 2 formed by joining multiple punched members W with an adhesive with high precision.

[0100] (7) When the sensor SE is located in the recess P4a of the punch P4, it may be configured to measure the distance between the lower end surface of the punch P4 and the central part (near the center) of the upper end surface of the cylinder 142. In this case, even if the cylinder 142 is tilted in the vertical direction due to dimensional tolerances present in the cylinder 142, the sensor SE can measure the distance more accurately. When the sensor SE is located in the recess 142a of the cylinder 142, it may be configured to measure the distance between the central part (near the center) of the lower end surface of the punch P4 and the upper end surface of the cylinder 142. In this case, even if the punch P4 is tilted in the vertical direction due to dimensional tolerances present in the upper die 120 or the tilt of the press machine 130, the sensor SE can measure the distance more accurately.

[0101] (8) During the press working of the metal sheet MS, the press oil (stamping oil) applied to the surface of the metal sheet MS may spread around in a mist-like manner. Therefore, whether the sensor SE is located in the recess P4a of the punch P4 or in the recess 142a of the cylinder 142, the sensor SE may be covered with a transparent material (for example, a glass plate). In this case, the adhesion of oil to the sensor SE is suppressed by the transparent material. As a result, the separation distance can be measured more accurately by the sensor SE.

[0102] An oil-repellent coating may be formed on the surface of the transparent member. In this case, the coating prevents oil from adhering to the transparent member. Therefore, the sensor SE can measure the separation distance more accurately. The transparent member may be installed so as to be inclined with respect to the horizontal plane. In this case, oil adhering to the transparent member will flow down along the inclination of the transparent member, so the coating prevents oil from adhering to the transparent member. Therefore, the sensor SE can measure the separation distance more accurately.

[0103] A removal unit for removing oil adhering to the surface of the transparent member may be provided near the punch P4 or cylinder 142. The removal unit may be, for example, a gas supply unit configured to blow off the oil from the surface of the transparent member by blowing gas (e.g., air, inert gas, etc.) toward the surface of the transparent member. Alternatively, the removal unit may be a wiping unit (e.g., a wiper mechanism) configured to wipe the surface of the transparent member. In this case, the oil adhering to the surface of the transparent member is removed by the removal unit. As a result, the separation distance can be measured more accurately by the sensor SE.

[0104] [Other examples] Example 1. An example of a method for manufacturing a laminated iron core includes inserting a punch for punching out the outer shape into a die provided with a die hole for punching out the outer shape, repeatedly punching out a metal plate into a predetermined shape with the punch and pressing it toward a cylinder located below the die, thereby stacking multiple punched-out members within the die to form a laminate, acquiring the distance between the punch and the cylinder using a sensor when the punch reaches near the bottom dead center during the process of punching out the members from the metal plate, and calculating the stacked thickness of the multiple punched-out members stacked within the die based on the distance acquired by the sensor. In this case, the distance acquired by the sensor is the stacked thickness of the multiple punched-out members under pressure from the punch and cylinder. Therefore, even if there is a thickness deviation in the metal plate, the pressure from the punch and cylinder makes it easier for the multiple punched-out members to adhere closely together, and the gaps between the multiple punched-out members are greatly reduced, allowing the stacked thickness to be acquired while stacking the multiple punched-out members. Thus, it is possible to acquire the stacked thickness of the laminate in the process of stacking within the press working device with high accuracy.

[0105] Example 2. In the method of Example 1, the sensor may be located inside the punch or inside the cylinder. In this case, it is not necessary to significantly modify the press working apparatus in order to attach the sensor to the press working apparatus. Therefore, it is possible to attach the sensor to an existing press working apparatus simply and inexpensively.

[0106] Example 3. The method of Example 1 or Example 2 may further include calculating the amount of change over time of the separation distance acquired by the sensor over a predetermined period, and, based on the amount of change over time, calculating the number of punches of the metal sheet by the punch and die until the stacked thickness of the multiple punched members stacked in the die reaches a predetermined target stacked thickness. Incidentally, in the die, multiple punched members may be stacked on top of an already completed stack before the stack is discharged from the die. In this case, in order to prevent the punched members that will make up the next stack from bonding to the already completed stack in the die, a through hole is formed in the first punched member that will make up the next stack, rather than crimping. Since the crimping or through hole formation process is upstream of the outer shape punching process, it is necessary to determine when to form the through hole before the punched members that will make up the next stack are punched, that is, before the stack currently being manufactured is completed. In this regard, according to Example 3, the number of punches required to reach the target stacking thickness is calculated based on the rate of change over time, making it possible to more accurately determine the timing of forming through holes in the punched members that constitute the next laminate to be manufactured.

[0107] Example 4. In the method of Example 3, calculating the amount of change over time may include calculating a predicted value of the current separation distance based on the amount of change over time of the separation distance acquired by the sensor over a predetermined past period, and calculating the amount of change over time by excluding the current separation distance acquired by the sensor when the difference between the current separation distance acquired by the sensor and the predicted value is outside a predetermined range. In this case, even if there is a large error in the data of the current separation distance acquired by the sensor due to false detection by the sensor or detection of foreign matter such as dust by the sensor, such data will be excluded. Therefore, it becomes possible to determine the timing of the formation of through holes in the punched members that constitute the next laminate to be manufactured with even greater accuracy.

[0108] Example 5. In the method of Example 3 or Example 4, calculating the amount of change over time may include calculating the moving average value of the separation distance acquired by the sensor over a predetermined period. In this case, the time-series data of the separation distance acquired by the sensor is smoothed. Therefore, even if there are large fluctuations or errors in the data of the separation distance, their effects are reduced. Thus, by using the moving average value as the amount of change over time, it becomes possible to calculate the number of punches in the metal plate more accurately.

[0109] Example 6. In any of the methods in Examples 1 to 5, calculating the stacked thickness of multiple punched members may include calculating the stacked thickness of multiple punched members stacked within the die by sequentially adding the separation distances acquired by the sensor. In this case, the stacked thickness of multiple punched members can be calculated using an extremely simple method.

[0110] Example 7. Any method from Examples 1 to 5 further includes measuring the stack thickness of the laminate discharged from the die using a measuring device, and calculating the stack thickness of multiple punched members may include calculating the stack thickness of multiple punched members stacked in the die based on the stack thickness of the laminate measured by the measuring device and the separation distance acquired by the sensor. In this case, the stack thickness of a completed laminate is measured more accurately by the measuring device. Therefore, by using the measurement value from the measuring device and the separation distance acquired by the sensor, it becomes possible to obtain the stack thickness of the laminate in progress as it is being stacked in the press working machine with higher accuracy.

[0111] Example 8. An example of a laminated iron core manufacturing apparatus comprises a die with an outer die hole configured to punch out a metal plate into a predetermined shape, an outer punch configured to be insertable into and removable from the die hole, a cylinder positioned below the die, a sensor configured to acquire the distance between the punch and the cylinder, and a control unit. The control unit is configured to perform the following processes: controlling the punch so that it is inserted into the die, and repeatedly pressing the metal plate toward the cylinder while punching it into a predetermined shape with the punch, thereby stacking multiple punched members punched out from the metal plate within the die to form a laminate; acquiring the distance between the punch and the cylinder using the sensor when the punch reaches near the bottom dead center during the process of punching out the members from the metal plate; and calculating the stacking thickness of the multiple punched members stacked within the die based on the distance acquired by the sensor. In this case, the same effects and advantages as in Example 1 can be obtained.

[0112] Example 9. In the apparatus of Example 8, the sensor may be provided inside the punch or cylinder via a heat dissipation mechanism. In this case, the heat generated in the sensor during operation is dissipated via the heat dissipation mechanism. Therefore, temperature drift due to temperature changes in the sensor is reduced. Consequently, it becomes possible to obtain the stacking thickness of the laminate in the process of stacking within the press working apparatus with higher accuracy. [Explanation of symbols]

[0113] 1... Rotor laminated core, 2... Laminate, 10... Manufacturing equipment for rotor laminated core, 100... Pressing equipment, 142... Cylinder, 151... Heat sink (heat dissipation mechanism), 200... Lamination thickness measuring device (measuring device), Ctr... Controller (control unit), D4... Die, MS... Metal plate, P4... Punch, SE... Sensor, W... Punching member.

Claims

1. By inserting a punch for punching out the outer shape into a die provided with a die hole for punching out the outer shape, and repeatedly pressing a metal plate toward a cylinder located below the die while punching it into a predetermined shape with the punch, a plurality of punched-out members are stacked within the die to form a laminate, During the process in which the punching member is punched out of the metal plate, the distance between the lower end surface of the punch and the central part of the upper end surface of the cylinder when the punch reaches near the bottom dead center is obtained by a sensor. This includes calculating the stacking thickness of the plurality of punched members stacked in the die based on the separation distance obtained by the sensor, The lower end surface of the punch is provided with a recess that extends toward the upper end of the punch. The sensor is disposed within the recess, and the method for manufacturing a laminated iron core.

2. A die provided with a die hole for punching out the outer shape, into which a punch for punching out the outer shape is inserted, and a metal plate is repeatedly punched out into a predetermined shape by the punch while being pressed toward a cylinder located below the die, thereby stacking a plurality of punched-out members within the die to form a laminate, The distance between the punch and the cylinder when the punch reaches near the bottom dead center during the process in which the punching member is punched out from the metal plate is obtained by a sensor, Based on the separation distance obtained by the sensor, the stacking thickness of the plurality of punched members stacked in the die is calculated, To calculate the amount of change over time of the separation distance acquired by the sensor over a predetermined period, A method for manufacturing a laminated iron core, comprising calculating the number of punching operations of the metal plate by the punch and the die until the stacked thickness of the plurality of punched members laminated in the die reaches a predetermined target stacked thickness, based on the amount of change over time.

3. Calculating the aforementioned time change means Based on the amount of change over time of the distance acquired by the sensor over a predetermined past period, a predicted value of the current distance is calculated. The method according to claim 2, further comprising: when the difference between the current distance obtained by the sensor and the predicted value is outside a predetermined range, excluding the current distance obtained by the sensor and calculating the amount of change over time.

4. The method according to claim 2 or 3, wherein calculating the amount of change over time includes calculating the moving average value of the separation distance acquired by the sensor over a predetermined period.

5. A die provided with a die hole for punching out the outer shape, into which a punch for punching out the outer shape is inserted, and a metal plate is repeatedly punched out into a predetermined shape by the punch while being pressed toward a cylinder located below the die, thereby stacking a plurality of punched-out members within the die to form a laminate, The distance between the punch and the cylinder when the punch reaches near the bottom dead center during the process in which the punching member is punched out from the metal plate is obtained by a sensor, This includes calculating the stacking thickness of the plurality of punched members stacked in the die based on the separation distance obtained by the sensor, Calculating the stacking thickness of the aforementioned multiple punched members is The separation distance acquired by the sensor at the first time point is subtracted from the separation distance acquired by the sensor at the second time point, which is the time after one punched member has been punched out of the metal plate by the punch, to calculate the difference value. A method for manufacturing a laminated iron core, comprising calculating the stacking thickness of the plurality of punched members stacked in the die by sequentially adding the aforementioned difference values.

6. A die provided with a die hole for punching out the outer shape, into which a punch for punching out the outer shape is inserted, and a metal plate is repeatedly punched out into a predetermined shape by the punch while being pressed toward a cylinder located below the die, thereby stacking a plurality of punched-out members within the die to form a laminate, The distance between the punch and the cylinder when the punch reaches near the bottom dead center during the process in which the punching member is punched out from the metal plate is obtained by a sensor, Based on the separation distance obtained by the sensor, the stacking thickness of the multiple punched members stacked in the die is calculated. This includes measuring the stacking thickness of the laminate discharged from the die using a measuring device, A method for manufacturing a laminated iron core, comprising calculating the stacking thickness of the plurality of punched members, which includes calculating the stacking thickness of the plurality of punched members stacked in the die based on the stacking thickness of the laminate measured by the measuring device and the separation distance obtained by the sensor.

7. A die equipped with an outer die hole configured to punch out a metal plate into a predetermined shape, A punch for cutting out an outer shape, configured to be insertable and removable from the die hole, A cylinder positioned below the die, Sensors and, It includes a control unit, The lower end surface of the punch is provided with a recess that extends toward the upper end of the punch. The sensor is positioned within the recess and is configured to measure the distance between the lower end surface of the punch and the central part of the upper end surface of the cylinder. The control unit, The process involves controlling the punch so that it is inserted into the die, and repeatedly pressing the metal plate toward the cylinder while punching it into a predetermined shape with the punch, thereby stacking multiple punched-out members within the die to form a laminate. The process of obtaining, by the sensor, the distance between the lower end surface of the punch and the central part of the upper end surface of the cylinder when the punch reaches near the bottom dead center during the process in which the punching member is punched out from the metal plate, A manufacturing apparatus for laminated iron cores, configured to perform a process of calculating the stacking thickness of the plurality of punched members stacked in the die based on the separation distance acquired by the sensor.

8. The apparatus according to claim 7, wherein the sensor is provided in the recess via a heat dissipation mechanism.

9. A die provided with an outer die hole configured to punch out a metal plate into a predetermined shape, A punch for cutting out an outer shape, configured to be insertable and removable from the die hole, A cylinder positioned below the die, A sensor configured to acquire the distance between the punch and the cylinder, It includes a control unit, The control unit, The process involves controlling the punch so that it is inserted into the die, and repeatedly pressing the metal plate toward the cylinder while punching it into a predetermined shape with the punch, thereby stacking multiple punched-out members within the die to form a laminate. A process to acquire the distance between the punch and the cylinder using the sensor when the punch reaches near the bottom dead center during the process in which the punching member is punched out from the metal plate, A process for calculating the stacking thickness of the multiple punched members stacked in the die based on the separation distance obtained by the sensor, A process for calculating the amount of change over time of the separation distance acquired by the sensor over a predetermined period, A manufacturing apparatus for laminated iron cores, configured to perform a process of calculating the number of punching operations of the metal plate by the punch and the die until the stacked thickness of the plurality of punched members stacked in the die reaches a predetermined target stacked thickness, based on the aforementioned amount of change over time.

10. A die provided with an outer die hole configured to punch out a metal plate into a predetermined shape, A punch for cutting out an outer shape, configured to be insertable and removable from the die hole, A cylinder positioned below the die, A sensor configured to acquire the distance between the punch and the cylinder, It includes a control unit, The control unit, The process involves controlling the punch so that it is inserted into the die, and repeatedly pressing the metal plate toward the cylinder while punching it into a predetermined shape with the punch, thereby stacking multiple punched-out members within the die to form a laminate. A process to acquire the distance between the punch and the cylinder using the sensor when the punch reaches near the bottom dead center during the process in which the punching member is punched out from the metal plate, The system is configured to perform a process of calculating the stacking thickness of the multiple punched members stacked in the die based on the separation distance obtained by the sensor, The process for calculating the stack thickness of the aforementioned multiple punched members is as follows: The separation distance acquired by the sensor at the first time point is subtracted from the separation distance acquired by the sensor at the second time point, which is the time after one punched member has been punched out of the metal plate by the punch, to calculate the difference value. A manufacturing apparatus for laminated iron cores, comprising calculating the stacking thickness of the plurality of punched members stacked in the die by sequentially adding the aforementioned difference values.

11. A die provided with an outer die hole configured to punch out a metal plate into a predetermined shape, A punch for cutting out an outer shape, configured to be insertable and removable from the die hole, A cylinder positioned below the die, A sensor configured to acquire the distance between the punch and the cylinder, It includes a control unit, The control unit, The process involves controlling the punch so that it is inserted into the die, and repeatedly pressing the metal plate toward the cylinder while punching it into a predetermined shape with the punch, thereby stacking multiple punched-out members within the die to form a laminate. A process to acquire the distance between the punch and the cylinder using the sensor when the punch reaches near the bottom dead center during the process in which the punching member is punched out from the metal plate, A process for calculating the stacking thickness of the multiple punched members stacked in the die based on the separation distance obtained by the sensor, The system is configured to perform a process of measuring the stacking thickness of the laminate discharged from the die using a measuring device, A manufacturing apparatus for a laminated iron core, wherein the process for calculating the stacking thickness of the plurality of punched members includes calculating the stacking thickness of the plurality of punched members stacked in the die based on the stacking thickness of the laminate measured by the measuring device and the separation distance acquired by the sensor.

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