Determination device, determination method, and press working apparatus

Abstract

The present invention provides a determination device capable of determining whether the clearance between the side of the punch and the inner wall of the hollow part of the stripper is appropriate. [Solution] The determination device of this disclosure is a determination device for determining whether the size of the clearance between the side surface of the punch and the inner wall of the hollow portion of the stripper is appropriate in a press die having a punch, a stripper into which the punch is inserted, and a die, and comprises a control unit that determines whether the clearance is appropriate based on the detected value of a load sensor when the punch is applied, and the control unit determines that the clearance is not appropriate when the detected value of the load sensor exceeds a predetermined threshold.

Description

【Technical Field】 【0001】 The present disclosure relates to a determination device, a determination method, and a pressing device. 【Background Art】 【0002】 For example, Patent Document 1 discloses a press die manufactured by stacking and mounting at least two die parts in a fitting relationship with a punch on a mounting table of a hole processing machine and simultaneously processing holes. 【Prior Art Document】 【Patent Document】 【0003】 【Patent Document 1】 Japanese Patent Application Laid-Open No. 5-115929 【Summary of the Invention】 【Problems to be Solved by the Invention】 【0004】 In the punch die described in Patent Document 1, there is still room for improvement in determining whether the clearance between the punch and the die part in a fitting relationship is appropriate. 【0005】 The present disclosure provides a determination device, a determination method, and a pressing device capable of determining whether the size of the clearance between the side surface of the punch and the inner wall of the hollow part of the stripper is appropriate. 【Means for Solving the Problems】 【0006】 A determination device according to an aspect of the present disclosure is in a press die having a punch, a stripper in which a hollow part into which the punch is inserted is formed, and a die, and is a determination device for determining whether the size of the clearance between the side surface of the punch and the inner wall of the hollow part of the stripper is appropriate, a load sensor that detects the load applied to the punch, A control unit that determines whether the clearance is appropriate based on the detected value of the load sensor, Equipped with, The control unit determines that the clearance is not appropriate when the detected value of the load sensor exceeds a predetermined threshold. 【0007】 The determination method relating to one aspect of this disclosure is: A method for determining whether the clearance between the side surface of the punch and the inner wall of the hollow portion of the stripper is appropriate in a press die having a punch, a stripper into which the punch is inserted, and a die, A step of detecting the load applied to the punch, A step of determining whether the clearance is appropriate based on the detected load, Includes, The step of determining whether the clearance is appropriate includes determining that the clearance is not appropriate if the detected load exceeds a predetermined threshold. 【0008】 A press working apparatus according to one aspect of this disclosure is: A stripper having a hollow section into which the punch is inserted, Dai and, The above-mentioned determination device, It is equipped with. [Effects of the Invention] 【0009】 According to this disclosure, it is possible to provide a determination device, a determination method, and a press working apparatus that can determine whether the size of the clearance between the side of the punch and the inner wall of the hollow part of the stripper is appropriate. [Brief explanation of the drawing] 【0010】 [Figure 1] A schematic block diagram showing the determination device according to Embodiment 1. [Figure 2]Schematic diagram for explaining whether the clearance in the press die is appropriate or not using the determination device of FIG. 1 [Figure 3] Schematic diagram for explaining whether the clearance in the press die is appropriate or not using the determination device of FIG. 1 [Figure 4] Schematic diagram for explaining whether the clearance in the press die is appropriate or not using the determination device of FIG. 1 [Figure 5A] Diagram schematically explaining the movements of the punch, stripper, and die in the press die of FIG. 2 [Figure 5B] Diagram schematically explaining the movements of the punch, stripper, and die in the press die of FIG. 2 [Figure 5C] Diagram schematically explaining the movements of the punch, stripper, and die in the press die of FIG. 2 [Figure 5D] Diagram schematically explaining the movements of the punch, stripper, and die in the press die of FIG. 2 [Figure 5E] Diagram schematically explaining the movements of the punch, stripper, and die in the press die of FIG. 2 [Figure 5F] Diagram schematically explaining the movements of the punch, stripper, and die in the press die of FIG. 2 [Figure 5G] Diagram schematically explaining the movements of the punch, stripper, and die in the press die of FIG. 2 [Figure 6] Schematic diagram for explaining the clearance between the punch and the stripper [Figure 7] Flowchart for explaining the determination process of whether the clearance is appropriate or not by the determination device [Figure 8] Graph showing the relationship between the load on the punch and time when the clearance between the punch and the stripper is appropriate [Figure 9] Graph showing the relationship between the load on the punch and time when the clearance between the punch and the stripper is not appropriate [Figure 10]Diagram schematically showing the load sensor included in the determination device according to Modification 1 of Embodiment 1 [Figure 11] Diagram schematically showing the press working device according to Embodiment 2 [Figure 12] Graph showing the relationship between the load applied to the punch and time obtained with the press working device of FIG. 11 [Figure 13] Graph showing the relationship between the load applied to the punch and time obtained with the press working device of FIG. 11 【Mode for Carrying Out the Invention】 【0011】 (Background Leading to the Present Disclosure) In press working for punching a plate-shaped workpiece, generally, the workpiece placed on the die is held by a stripper or a stripper plate or the like while a part of the workpiece is punched into a predetermined shape by a punch, thereby obtaining a desired shape. Press working by punching is used in a wide variety of fields such as home appliances, precision machinery, or automotive parts. 【0012】 When processing small parts or the like, the size of the hole to be punched may be small or the workpiece may be thin. In this case, the size of the tip of the punch also becomes small according to the size of the hole to be punched or the thickness of the workpiece. When the tip of the punch becomes small, the strength of the punch may also decrease. Therefore, in order to suppress breakage of the punch, it has been considered to guide the tip of the punch in a hollow portion provided in the stripper or the stripper plate for inserting the punch. 【0013】 When guiding the tip of the punch in the hollow portion of the stripper or the stripper plate, it is required to appropriately maintain the clearance between the inner wall of the hollow portion of the stripper or the stripper plate and the side surface of the punch. If the clearance is not appropriate, the sliding resistance when moving the punch becomes large, and seizure may occur on the punch. 【0014】 The present inventors (et al.) have investigated a determination device, a determination method, and a press working apparatus equipped with the determination device that can determine whether or not the clearance is appropriate, and have arrived at the following invention. 【0015】 The embodiments of this disclosure will be described below with reference to the attached drawings. In addition, in each drawing, the elements are exaggerated to facilitate the explanation. 【0016】 In this specification, terms such as “First,” “Second,” etc., are used for illustrative purposes only and should not be understood as expressing or implying relative importance or ranking of technical features. Features designated as “First” or “Second” express or imply that they include one or more such features. 【0017】 (Embodiment 1) [Overall structure] Figure 1 is a schematic block diagram showing the determination device 100 according to Embodiment 1. Figures 2 to 4 are schematic diagrams illustrating the determination of whether or not the clearance in the press die 150 is appropriate using the determination device of Figure 1. Note that the XYZ coordinate system shown in the figures is for the purpose of facilitating understanding of the embodiment and is not intended to limit the embodiment. In each figure, the X direction indicates the width direction of the press die 150, the Y direction indicates the depth direction of the press die 150, and the Z direction indicates the height direction of the press die 150. 【0018】 <Judgment device> The determination device 100 is a device for determining whether the clearance between the side surface 1b of the punch 1 and the inner wall of the hollow portion 3a of the stripper 3 in the press die 150, which will be described in detail later, is appropriate. 【0019】 As shown in Figure 1, the determination device 100 includes a load sensor 6 and a control unit 12. 【0020】 The load sensor 6 is a sensor that detects the load applied to the punch 1. In this embodiment, as shown in Figures 2 to 4, the load sensor 6 is located on the side of the punch 1 opposite to the press surface 1a. Also, in this embodiment, one load sensor 6 is located on the punch 1. As the load sensor 6, for example, a piezoelectric force sensor or an electrical force sensor such as a strain gauge type can be used. 【0021】 The control unit 12 determines whether the clearance is appropriate based on the detected value of the load sensor 6. The control unit 12 is composed of digital circuits such as a microcontroller, CPU, MPU, GPU, DSP, FPGA, ASIC, etc. In this embodiment, as shown in Figures 2 to 4, the control unit 12 includes, for example, a sensor controller 13 that controls the load sensor 6, a calculation unit 14, and a determination unit 15. 【0022】 The sensor controller 13 is electrically connected to the load sensor 6 and outputs the detected value of the load sensor 6 to the calculation unit 14. The calculation unit 14 calculates the relationship between the load applied to the punch 1 and time based on the load detected by the load sensor 6. The relationship between the load applied to the punch 1 and time will be described in detail later. The determination unit 15 determines whether the clearance between the punch 1 and the stripper 3 is appropriate. 【0023】 <Press die> Referring to Figures 2 to 4, the press die 150 that is subject to judgment by the judgment device 100 will be described. 【0024】 As shown in Figures 2 to 4, the press die 150 includes a punch 1, a stripper 3 into which a hollow portion 3a into which the punch 1 is inserted is formed, and a die 2. In this embodiment, the press die 150 is composed of an upper die 101 including the punch 1 and a lower die 102 including the die 2. The press die 150 is mounted on a press working device (not shown) and used to punch out a workpiece (not shown) placed on the die 2. 【0025】 The upper die 101 houses the punch 1 and the load sensor 6. The upper die 101 also houses a punch plate 27 for fixing the punch 1 and the load sensor 6, a backing plate 28, and an upper die set 29. 【0026】 The upper die 101 further includes a stripper 3, a stripper plate 4, a stripper guide pin 8, a stripper guide bush 9, a stripper bolt 7, and an upper stopper 25. The stripper plate 4 is a component that holds the stripper 3. The stripper guide pin 8 is a component that positions the stripper plate 4. The stripper guide bush 9 is a component that positions the stripper guide pin 8. The stripper bolt 7 is a component that holds the stripper plate 4 and moves the stripper 3. The upper stopper 25 is a component that restricts the movement of the punch 1 in the pressing direction (+Z direction). Note that when the press die 150 is mounted on a press working device and it is determined whether the clearance between the punch 1 and the stripper 3 is appropriate, the upper stopper 25 does not necessarily restrict the movement of the punch 1. 【0027】 Punch 1 is a tool that moves in the pressing direction (Z direction) to punch out a workpiece. As shown in Figures 2 to 4, punch 1 has a pressing surface 1a that faces the workpiece and a side surface 1b that connects to the pressing surface 1a. 【0028】 In this embodiment, the punch 1 has a press surface 1a that is formed in a circular cylindrical shape with a diameter of 4.5 mm. 【0029】 Punch 1 is made of, for example, a cemented carbide material. An example of a cemented carbide material is an artificial metal (alloy) in which at least one carbide from the nine types of metals W (tungsten), Cr (chromium), Mo (molybdenum), Ti (titanium), Zr (zirconium), Hf (hafnium), V (vanadium), Nb (niobium), and Ta (tantalum) is bonded with an Fe group metal (e.g., Fe, Co, or Ni). As the cemented carbide material that makes up Punch 1, for example, an alloy equivalent to VF-20 of the Carbide Tool Standards Association (CIS) can be used. 【0030】 The stripper 3 is a tool used to hold down the workpiece placed on the die 2 when punching out the workpiece with the punch 1. The stripper 3 is provided with a hollow section 3a into which the punch 1 is inserted. The hollow section 3a is formed in the form of a through hole into which the punch 1 can be inserted. In this embodiment, the hollow section 3a has a circular cross-section with a diameter of 4.502 mm and is a through hole that penetrates the stripper 3 in the Z direction. 【0031】 Stripper 3, like punch 1, is constructed from, for example, a cemented carbide material. The cemented carbide material used for stripper 3 can be an alloy equivalent to VM-30 of the Carbide Tool Standards Association (CIS). 【0032】 The lower die 102 contains the die 2, the stripper guide bush 10, and the lower stopper 26. The lower die 102 also contains the die plate 5 for fixing the die 2, the die backing plate 30 for dispersing the impact during processing, and the lower die set 31. The stripper guide bush 10 is a component that positions the stripper guide pin 8. The lower stopper 26 is a component that restricts the movement of the punch 1. 【0033】 In this embodiment, a position sensor 11 is positioned on the lower die 102. The position sensor 11 detects the distance of the punch 1 from the bottom dead center by detecting the position of the block 32 positioned on the upper die 101. The bottom dead center refers to the lowest position the punch 1 can reach. The position sensor 11 is composed of, for example, a displacement sensor that can measure minute distances to the object being measured without contact. 【0034】 The die 2 is a tool on which the workpiece is placed during press working. The die 2 is provided with a hollow section 2a into which the punch 1 is inserted. The hollow section 2a is formed in the form of a through hole into which the punch 1 can be inserted. In this embodiment, the hollow section 2a has a circular cross-section with a diameter of 4.506 mm and is a through hole that penetrates the die 2 in the Z direction. 【0035】 Die 2, like punch 1 and stripper 3, is constructed from, for example, a cemented carbide material. The cemented carbide material used for die 2 can be an alloy equivalent to VF-40 of the Carbide Tool Standards Association (CIS). 【0036】 Furthermore, in this embodiment, as shown in Figures 2 to 4, an output unit 16 is connected to the control unit 12 of the determination device 100. The output unit 16 is composed of, for example, a display that shows visual information such as a liquid crystal display, or a speaker that shows auditory information such as sound or a buzzer. 【0037】 [Determining whether clearance is appropriate] The determination of whether the clearance is appropriate or not by the determination device 100 will be explained with reference to Figures 2 to 4 and Figures 5A to 5G. Figures 5A to 5G are diagrams that schematically illustrate the movements of the punch 1, stripper 3, and die 2 in the press mold 150 of Figure 2. 【0038】 In this embodiment, the control unit 12 determines whether the clearance is appropriate based on the value detected by the load sensor 6 when the punch 1 is moved while the press die 150 is not mounted on the press working device. The determination of whether the clearance is appropriate is made based on the value detected by the load sensor when the upper die 101, located above the lower die 102 of the press die 150 shown in Figures 2 to 4, is lowered toward the lower die 102 until the punch 1 reaches its bottom dead center, and then the upper die 101 is raised again. The lowering and raising of the upper die 101 is performed, for example, by moving the upper die 101 up and down using a crane or the like with suspension bolts attached to the upper die set 29. 【0039】 Figure 2 shows the state where the upper die 101 has not moved from its initial position. That is, in Figure 2, the punch 1 is at top dead center, which is the highest position the punch 1 can take. In the state shown in Figure 2, no load is applied to the punch 1, so the value detected by the load sensor 6 is 0. At this time, the punch 1, die 2, and stripper 3 are in the positional relationship shown in Figure 5A. 【0040】 Figure 3 shows the state when the upper die 101 begins to descend and the stripper plate 4 and die plate 5 come into contact. At this time, the punch 1, die 2, and stripper 3 are in the positional relationship shown in Figure 5B. As the upper die 101 descends further after the stripper plate 4 and die plate 5 come into contact, the stripper 3 remains stationary while the punch 1 descends further. As the upper die 101 descends further from the state shown in Figures 3 and 5B, the punch 1 changes position from the position shown in Figure 5B to the position shown in Figure 5C. Between Figures 5B and 5C, the die 2 and stripper 3 remain in the same position, while only the position of the punch 1 changes. Therefore, as the upper die 101 descends further from the state shown in Figure 3, the punch 1 begins to move relative to the stripper 3. As the punch 1 moves relative to the stripper 3, sliding resistance is generated between the inner wall of the hollow portion 3a of the stripper 3 and the side surface 1b of the punch 1. This sliding resistance becomes a load on the punch 1. Therefore, when the upper die 101 begins to descend and reaches the state shown in Figure 3, a load begins to be applied to the punch 1. 【0041】 Figure 4 shows the state where the upper die 101 has descended further and the punch 1 is at its bottom dead center. At this time, the punch 1, die 2, and stripper 3 are in the positional relationship shown in Figure 5D. When the punch 1 is stationary at the bottom dead center, sliding resistance continues to be applied between the side surface 1b of the punch 1 and the inner wall of the hollow portion 3a of the stripper 3, and the value detected by the load sensor 6 is approximately the same as when the punch 1 reached the bottom dead center. 【0042】 From the state shown in Figure 4, the upper die 101 moves away from the lower die 102, and the press die 150 returns to the state shown in Figure 2 via the state shown in Figure 3. The relative positions of the punch 1, die 2, and stripper 3 change from the state shown in Figure 5D, where the punch 1 is at its bottom dead center, to the state shown in Figures 5E and 5F, and then return to the state shown in Figure 5G. Note that the relative positions of the punch 1, die 2, and stripper 3 are the same in Figures 5A and 5G. 【0043】 Next, with reference to Figure 6, the clearance between the side surface 1b of the punch 1 and the inner wall of the hollow portion 3a of the stripper 3 will be described. Figure 6 is a schematic diagram illustrating the clearance between the punch 1 and the stripper 3. 【0044】 As described above, the press surface 1a of punch 1 is formed in a circular shape with a diameter of 4.5 mm. The hollow portion 3a of stripper 3 is formed as a through-hole with a circular cross-section to allow punch 1 to be inserted. The diameter of the cross-section of the hollow portion 3a of stripper 3 is 4.502 mm. Therefore, the clearance c1 between the inner wall of the hollow portion 3a of stripper 3 and the side surface 1b of punch 1 is c1 = 0.001 mm, as shown in Figure 6. The hollow portion 2a of die 2 is also formed as a through-hole with a circular cross-section to allow punch 1 to be inserted. The diameter of the cross-section of the hollow portion 2a of die 2 is 4.506 mm. Therefore, the clearance c2 between the hollow portion 2a of die 2 and punch 1 is c2 = 0.003 mm. Note that the shapes and sizes of punch 1, the hollow portion 3a of stripper 3, and the hollow portion 2a of die 2 are merely examples and are not limited to those described above. 【0045】 Generally, the positional relationship between the punch 1 and die 2 is adjusted so that the clearance between the die 2 and punch 1 is about 1 / 10 of the thickness of the workpiece. In order to guide the punch 1 in the hollow portion 3a of the stripper 3, it is preferable that the clearance between the stripper 3 and punch 1 be smaller than the clearance between the die 2 and punch 1. For this reason, the positional relationship between the punch 1 and stripper 3 is adjusted so that the clearance c1 between the stripper 3 and punch 1 is between 1 / 3 and 1 / 2 of the clearance c2 between the die 2 and punch 1. In this embodiment, the appropriate value of the clearance c1 between the punch 1 and stripper 3 can be, for example, 0.001 mm or more and 0.0015 mm or less. 【0046】 Figure 7 is a flowchart illustrating the clearance determination process performed by the determination device 100. The clearance determination process will be explained with reference to Figure 7. 【0047】 In step S1, the load on the punch 1 is detected by the load sensor 6 from the time the upper die 101 descends toward the lower die 102 until the upper die 101 rises again and returns to its original position. 【0048】 Next, in step S2, the control unit 12 determines whether the load value applied to the punch 1 detected by the load sensor 6 exceeds a predetermined threshold. 【0049】 If the load applied to punch 1 exceeds a predetermined threshold, i.e., if step S2 is YES, in step S3, the control unit 12 determines that the clearance is not appropriate. 【0050】 If the load applied to punch 1 is below a predetermined threshold, i.e., step S2 is NO, then in step S4, the control unit 12 determines that the clearance is appropriate. 【0051】 The processes in steps S1 through S4 are explained in detail below. 【0052】 In step S1, the load sensor 6 detects the load applied to the punch 1 from the moment the punch 1 begins to move from the top dead center towards the bottom dead center until the punch 1 reaches the bottom dead center and then returns to the top dead center. For example, the movement of the punch 1 can be detected by detecting the position of the punch 1 using the position sensor 11. At this time, the sensor controller 13 of the control unit 12 outputs the value detected by the load sensor 6 to the calculation unit 14 of the control unit 12. 【0053】 In step S2, the calculation unit 14 of the control unit 12 calculates the relationship between the detected value of the load sensor 6 and time. The relationship between the detected value of the load sensor 6 and time can be represented, for example, by the graph shown in Figure 8. Figure 8 is a graph showing the relationship between the load on the punch 1 and time when the clearance between the punch 1 and the stripper 3 is appropriate. 【0054】 In the graph of Figure 8, the left vertical axis shows the load on the punch (unit: N), the right vertical axis shows the distance of punch 1 from the bottom dead center (unit: mm), and the horizontal axis shows time (unit: msec). The dashed line graph shows the distance of punch 1 from the bottom dead center, i.e., the position of the punch, and the dashed line graph shows the load on punch 1. The graph of Figure 8 shows that at time 0, punch 1 is at the top dead center, and as time progresses, punch 1 descends and reaches the bottom dead center at time C2, and at time C3, punch 1 begins to rise again. The distance of punch 1 from the bottom dead center can be detected, for example, by a position sensor 11. 【0055】 As the upper die 101 is lowered, the punch 1 descends from the top dead center together with the stripper 3. At time C1, the stripper plate 4 and the die plate 5 come into contact. In the example in Figure 8, time T0 has elapsed until time C1, that is, from when the punch 1 begins to descend toward the bottom dead center until the stripper plate 4 and the die plate 5 come into contact. 【0056】 When the upper die 101 is lowered further, the stripper plate 4 and the die plate 5 come into contact, stopping the stripper 3 from descending, but the punch 1 continues to descend. At this time, the punch 1 moves relative to the stripper 3, generating sliding resistance between the inner wall of the hollow portion 3a of the stripper 3 and the side surface 1b of the punch 1. A load due to the sliding resistance between the stripper 3 and the punch 1 is applied to the punch 1, and this load is detected by the load sensor 6. Figure 8 shows that the load sensor 6 detected a load of magnitude P1. The sliding resistance is almost constant when the punch 1 is descending while the stripper 3 is stationary. 【0057】 When the upper die 101 is lowered further, the upper stopper 25 and the lower stopper 26 come into contact at time C2, and the lowering of the upper die 101 stops. The time from time C1 until the lowering of the punch 1 stops is time T1. Between time C1 and time C2, as shown in Figure 8, a load of magnitude P1 is applied to the punch 1. 【0058】 Between time C2 and time C3, although punch 1 is stationary at its bottom dead center, sliding resistance is present, and therefore a load of magnitude P1 is applied to punch 1. The time during which punch 1 is stationary at its bottom dead center is time T2. 【0059】 Subsequently, when the upper die 101 is raised at time C3, the upper stopper 25 and the lower stopper 26 separate first, and the punch 1 rises while the stripper plate 4 and the die plate 5 remain in contact. Since the stripper plate 4 and the die plate 5 are still in contact, sliding resistance is generated again between the stripper 3 and the punch 1. 【0060】 As the upper die 101 continues to rise, the stripper plate 4 also begins to rise along with the upper die 101, and at time C4, the stripper plate 4 and the die plate 5 separate. The time from time C3 to time C4 is time T3. Between time C3 and time C4, the punch 1 is subjected to a load of the same magnitude P1 as from time C1 to time C2. 【0061】 After the stripper plate 4 and die plate 5 separate at time C4, the stripper 3 and punch 1 both rise, so the sliding resistance becomes 0 again, and the load on punch 1 also becomes 0. The time from time C4 to time C5 when punch 1 returns to top dead center is time T4. 【0062】 By performing the descent and ascent of the upper mold 101 at a predetermined speed, the timing of times C1 to C5 will be approximately the same each time. In other words, the length of time T0 to time T4 will be approximately the same each time. Therefore, instead of the position sensor 11, the timing of times C1 to C5 may be estimated by the time elapsed since the punch 1 began to descend. However, depending on the speed of the descent and ascent of the upper mold 101, the timing of times C1 to C5 may differ. 【0063】 As shown in Figure 8, a load is applied to the punch 1 between time C1 and time C4. In step S3, the determination unit 15 determines whether the clearance is appropriate based on the load sensor's detected values ​​from time 0, when the punch 1 begins to move from the top dead center towards the bottom dead center, to time C5, when the punch 1 reaches the bottom dead center and then returns to the top dead center again. In other words, the determination unit 15 can determine that the clearance is appropriate if the maximum load applied to the punch 1 from time 0 to time C5 is less than or equal to a predetermined threshold P2. 【0064】 The smaller the clearance between punch 1 and stripper 3, the greater the sliding resistance between punch 1 and stripper 3. Therefore, if the load applied to punch 1 exceeds a predetermined threshold P2, the determination unit 15 can determine that the clearance is too small and therefore improper. In this embodiment, the determination unit 15 makes a determination when the clearance is smaller than the appropriate value, but does not make a determination when the clearance is larger than the appropriate value. 【0065】 In the example shown in Figure 8, a load of magnitude P1 is applied to the punch 1 between time C1 and time C4. Since the load of magnitude P1 does not exceed a predetermined threshold P2, the determination unit 15 can determine that the clearance between the punch 1 and the stripper 3 is appropriate. 【0066】 The predetermined threshold P2 can be, for example, 1.0N. The predetermined threshold P2 can be determined by the material or thickness of the workpiece, and / or the punching shape by the punch 1, as well as the clearance and mold structure. 【0067】 Figure 9 is a graph showing the relationship between the load on punch 1 and time when the clearance between punch 1 and stripper 3 is not appropriate. In the graph of Figure 9, as in Figure 8, the left vertical axis shows the load on the punch (unit: N), the right vertical axis shows the distance of punch 1 from the bottom dead center (unit: mm), and the horizontal axis shows time (unit: msec). 【0068】 In the example shown in Figure 9, a load of magnitude P3 is applied to punch 1 between time C1 and time C4. Therefore, since the maximum value of the load applied to punch 1 between time 0 and time C5 exceeds a predetermined threshold P2, the determination unit 15 determines that the clearance between punch 1 and stripper 3 is not appropriate. 【0069】 After the determination unit 15 determines whether the clearance is appropriate, the control unit 12 may output the determination result to the output unit 16. Based on the determination result, the assembly of the press die 150 is adjusted, the clearance is adjusted, and then the clearance is determined again to ensure an appropriate clearance between the punch 1 and the stripper 3. 【0070】 In this embodiment, the appropriateness of the clearance between the punch 1 and the stripper 3 can be determined even before the press die 150 is mounted on the press working device. By determining the appropriateness of the clearance during the die adjustment stage before mounting it on the press working device, the clearance between the punch 1 and the stripper 3 can be set with greater precision. 【0071】 [effect] According to the above-described embodiment, the following effects can be achieved. 【0072】 The determination device 100 is a device that determines whether the clearance between the side surface 1b of the punch 1 and the inner wall of the hollow portion 3a of the stripper 3 is appropriate in a press die 150 having a punch 1, a stripper 3, and a die 2. The determination device 100 comprises a load sensor 6 and a control unit 12. The load sensor 6 detects the load applied to the punch 1. The control unit 12 determines whether the clearance is appropriate based on the value detected by the load sensor 6. The control unit 12 determines that the clearance is not appropriate if the value detected by the load sensor 6 exceeds a predetermined threshold P2. 【0073】 This configuration provides a determination device that can determine whether the clearance between the side of the punch and the inner wall of the hollow part of the stripper is appropriate. 【0074】 The control unit 12 determines whether the clearance is appropriate based on the values ​​detected by the load sensor 6 from the time the punch 1 starts moving from the top dead center towards the bottom dead center until the punch 1 reaches the bottom dead center and then returns to the top dead center again. 【0075】 This configuration allows for more accurate determination of whether the clearance is appropriate. 【0076】 The control unit 12 determines whether the clearance is appropriate based on the value detected by the load sensor 6 when the punch 1 is moved while the press die 150 is not mounted on the press working device. 【0077】 This configuration improves the maintainability of the press die 150. 【0078】 In a press die having a punch 1, a stripper 3, and a die 2, a method for determining whether the size of the clearance between the side surface 1b of the punch 1 and the inner wall of the hollow portion 3a of the stripper 3 is appropriate includes the steps of: detecting the load applied to the punch 1; and determining whether the clearance is appropriate based on the detected load. The step of determining whether the size of the clearance is appropriate includes determining that the clearance is not appropriate if the detected load exceeds a predetermined threshold. 【0079】 This configuration provides a determination method that can determine whether the clearance between the side of the punch and the inner wall of the hollow part of the stripper is appropriate. 【0080】 In the above-described embodiment, an example was given in which the press surface 1a of the punch 1 is formed in a circular shape, but the invention is not limited to this. The press surface 1a of the punch 1 may have any shape. Furthermore, the shapes of the hollow portion 3a of the stripper 3 and the hollow portion 2a of the die 2 can be arbitrarily set to match the shape of the punch 1. 【0081】 Furthermore, although the above-described embodiment explains an example in which the stripper 3 is fixed to the stripper plate 4, the invention is not limited to this. The stripper 3 and the stripper plate 4 may be integrally formed. 【0082】 Furthermore, although the above-described embodiment explains an example in which the die 2 is fixed to the die plate 5, the invention is not limited to this. The die 2 and the die plate 5 may be integrally formed. 【0083】 Furthermore, although the above-described embodiment mentions the use of a crane to raise and lower the upper mold 101, the invention is not limited to this. For example, instead of a crane, the upper mold 101 may be attached to a vertically movable device or the like to raise and lower the upper mold 101. 【0084】 In the above-described embodiment, an example was given in which the determination device 100 includes a load sensor 6, but the device is not limited to this. The control unit 12 of the determination device 100 may acquire information regarding the load of the punch 1 from an external source and determine whether the clearance is appropriate based on that information. 【0085】 Furthermore, although the above-described embodiment explains an example in which the position of the punch 1 is detected using the position sensor 11, the invention is not limited to this. The control unit 12 may also estimate the position of the punch 1 based on the time elapsed since the punch 1 began to descend. 【0086】 Furthermore, although the above-described embodiment described an example where the predetermined threshold P2 is 1.0N, the invention is not limited to this. The predetermined threshold P2 may be a value calculated by statistical processing or machine learning, etc. 【0087】 Furthermore, while the above-described embodiment explains an example of determining whether the clearance is appropriate based on the load applied to the punch 1 during one cycle from when the punch 1 reaches the bottom dead center and then returns to the top dead center, the method is not limited to this. For example, the cycle from when the punch 1 reaches the bottom dead center and then returns to the top dead center may be repeated multiple times, and the clearance may be determined based on the load applied to the punch 1. 【0088】 In the embodiment described above, the determination unit 15 of the control unit 12 determined whether the clearance was appropriate based on the detected value of the load sensor 6 from the time the punch 1 began to move from the top dead center to the bottom dead center until the time the punch 1 reached the bottom dead center and returned to the top dead center again. However, the embodiment is not limited to this. As explained with reference to Figures 8 to 9, a load is applied to the punch 1 between time C1 and time C4, and the load on the punch 1 is 0 between time 0 and time C1, and between time C4 and time C5. Therefore, the determination unit 15 may determine whether the clearance is appropriate based on the detected value of the load sensor for a predetermined period from the time the punch 1 began to move from the top dead center to the bottom dead center. Specifically, the determination unit 15 may determine whether the clearance between the punch 1 and the stripper 3 is appropriate based on the load applied to the punch 1 during the period between time C1 and time C4. 【0089】 [Differentiation] Figure 10 is a schematic diagram showing a load sensor 60 included in a determination device according to a modified example 1 of Embodiment 1. As shown in Figure 10, the load sensor 60 may include four load sensors 6a to 6d. In this case, the four load sensors 6a to 6d may be arranged at equal intervals on the side of the punch 1 opposite to the press surface 1a. In the example of Figure 10, the four load sensors 6a to 6d are arranged at 90-degree intervals along the outer circumference of the press surface 1a of the punch 1. Furthermore, the determination unit 15 of the control unit 12 may identify the location of the part of the side surface 1b of the punch 1 where the clearance is not appropriate based on the detected values ​​of the four load sensors 6a to 6d. With this configuration, the clearance between the punch 1 and the stripper 3 can be adjusted with greater precision. 【0090】 (Embodiment 2) Embodiment 2 will be described with reference to Figures 11 to 13. In Embodiment 2, components identical or equivalent to those in Embodiment 1 will be denoted by the same reference numerals. Also, in Embodiment 2, descriptions that overlap with those in Embodiment 1 will be omitted. 【0091】 Figure 11 is a schematic diagram of the press working apparatus 200 according to Embodiment 2. Figures 12 and 13 are graphs showing the relationship between the load applied to the punch 1 and time, obtained by the press working apparatus 200 in Figure 11. As shown in Figure 11, Embodiment 2 differs from Embodiment 1 in that the control unit 12 determines whether the clearance is appropriate based on the detected value of the load sensor 6 when the punch 1 is moved with the press die 150 mounted on the press working apparatus and the workpiece 22 placed on the die 2. 【0092】 The press working apparatus 200 comprises a punch 1, a stripper 3, a die 2, and a determination device 100, and is a device for punching out a workpiece 22. The press working apparatus 200 includes the press die 150 and the determination device 100 described in Embodiment 1. In Embodiment 2, the determination device 100 detects the load applied to the punch 1 when punching out the workpiece 22 in the press working apparatus 200 equipped with the press die 150, and determines whether the clearance between the punch 1 and the stripper 3 is appropriate based on the detected load. 【0093】 First, the press working apparatus 200 will be described with reference to Figure 11. The press working apparatus 200 is a device that performs punching on a plate-shaped workpiece 22. The press working apparatus 200 is, for example, a servo screw press that can be controlled with high precision. In the press working apparatus 200, the press die 150 is mounted on the press apparatus body 18. As shown in Figure 11, the upper die 101 of the press die 150 is attached to the slide 20 of the press apparatus body 18, and the lower die 102 of the press die 150 is attached to the bolster 21 of the press apparatus body 18. The upper die 101 is attached to the slide 20 via a spring 23 and a screw plug 24. The press die 150 has the same configuration as the press die 150 described in Embodiment 1, so its description will be omitted. 【0094】 In the press working apparatus 200, based on a command from the press controller 17, the servo motor 19 is rotated to drive the slide 20 up and down in the pressing direction (Z direction), thereby performing punching on the workpiece 22. During punching, the slide 20 descends, causing the stripper 3 to press the workpiece 22 against the die 2. With the workpiece 22 held down by the stripper 3, the punch 1 performs punching on the workpiece 22. 【0095】 In the press working apparatus 200, multiple workpieces 22 or workpieces 22 in the form of coil material are transported in the X or Y direction by a transport unit (not shown) in accordance with the pressing operation of the press apparatus body 18, and punching is performed sequentially. 【0096】 In this embodiment, the workpiece 22 is made of SUS301-EH material, which is a type of steel classified as austenitic stainless steel. SUS301-EH material is used, for example, as a spring or coil for automobile parts. The workpiece 22 has, for example, a thickness of 0.03 mm, a hardness of 529 HV, and a tensile strength of 1,679 N / mm². 2 That is the case. 【0097】 The press controller 17 drives the servo motor 19 to move the slide 20 up and down in the pressing direction (Z direction) at a predetermined speed. The press controller 17 is composed of digital circuits such as a microcontroller, CPU, MPU, GPU, DSP, FPGA, ASIC, etc. The press controller 17 may be the same hardware as the control unit 12 of the judgment device 100. 【0098】 The determination device 100 determines whether the clearance between the punch 1 and the stripper 3 is appropriate based on the value detected by the load sensor 6 when the punch 1 is moved with the press die 150 mounted on the press working device 200 and the workpiece 22 placed on the die 2. 【0099】 Referring to the graphs in Figures 12 and 13, the load applied to the punch 1 when punching out the workpiece 22 will be explained. When the press controller 17 drives the servo motor 19, the slide 20 descends together with the upper die 101. At time C10, the stripper plate 4 (stripper 3) and the die plate 5 (die 2) come into contact. Note that when punching out the workpiece 22, the stripper plate 4 (stripper 3) and the die plate 5 (die 2) may not come into direct contact, but rather come into contact via the workpiece 22. 【0100】 As the upper die 101 is lowered further, the stripper 3 remains stationary while the punch 1 descends between time C10 and time C11. At this time, sliding resistance occurs between the punch 1 and the stripper 3, and the load sensor 6 detects a load of magnitude P1 acting on the punch 1. 【0101】 At time C11, punch 1 contacts the workpiece 22. When punch 1 contacts the workpiece 22 and the upper die 101 is lowered, punch 1 punches out the workpiece 22. At time C12, the workpiece 22 is punched out by punch 1 and has a hole in it. The load sensor 6 detects the largest value of the load applied to punch 1 between time C11 and time C12. The load detected while punch 1 is punching out the workpiece 22, that is, between time C11 and time C12, is the load applied to punch 1 when punching out the workpiece 22 and cannot be used to determine the clearance. 【0102】 As the upper die 101 is lowered further, the punch 1 reaches its bottom dead center at time C13, and remains stationary at the bottom dead center from time C13 to time C14. Specifically, between time C12 and time C14, a load may be generated between the punch 1 and the workpiece 22, i.e., the scrap, which has been punched out by the punch 1 and fallen into the hollow part of the die 2. In this case, the load on the punch 1 may be greater than the magnitude P1. 【0103】 Subsequently, at time C14, the upper die 101 is raised again, and at time C15, the stripper plate 4 (stripper 3) and the die plate 5 (die 2), which were in contact via the workpiece 22, separate. 【0104】 The upper die 101 is further raised, and at time C16, punch 1 returns to its top dead center. The load on punch 1 between time C15 and time C16 is zero. 【0105】 As described above, the load sensor 6 detects the load when punching out the workpiece 22, and the load due to friction between the punched workpiece 22 and the punch 1. Therefore, in order to more accurately determine whether the clearance between the punch 1 and the stripper 3 is appropriate, the control unit 12 determines whether the clearance is appropriate based on the load detected by the load sensor 6 between time C10 and time C11, which is unaffected by the workpiece 22. In other words, the control unit 12 determines whether the clearance is appropriate based on the value detected by the load sensor 6 from the time the stripper 3 and die 2 come into contact via the workpiece 22 until the punch 1 comes into contact with the workpiece 22. 【0106】 The control unit 12 may determine whether the clearance is appropriate based on the detected value of the load sensor 6 between time C14 and time C15, when the influence of the workpiece 22 is minimal. In other words, the control unit 12 may determine whether the clearance is appropriate based on the detected value of the load sensor 6 from the time the punch 1 punches out the workpiece 22 and leaves the workpiece 22 until it returns to the top dead center. 【0107】 Figure 12 shows an example where the clearance between punch 1 and stripper 3 is appropriate, and Figure 13 shows an example where the clearance between punch 1 and stripper 3 is not appropriate. For example, in the example of Figure 12, the load applied to punch 1 between time C10 and time C11 is magnitude P1, which is smaller than a predetermined threshold P2. Therefore, in the case of Figure 12, the determination unit 15 of the control unit 12 determines that the clearance is appropriate. On the other hand, in the example of Figure 13, the load applied to punch 1 between time C10 and time C11 is magnitude P3, which exceeds a predetermined threshold P2. Therefore, in the case of Figure 13, the determination unit 15 of the control unit 12 determines that the clearance is not appropriate. The control unit 12 may output the determination result to the output unit 16. 【0108】 The control unit 12 can determine whether the clearance is appropriate during processing in the press working apparatus 200. If it is determined that the clearance is not appropriate during processing, the press controller 17 can stop the servo motor 19 to temporarily halt production and adjust the press die 150. 【0109】 (Note) The following technologies are disclosed by the embodiments described above. 【0110】 (Technology 1) A determination device for determining whether the clearance between the side of the punch and the inner wall of the hollow portion of the stripper is appropriate in a press die having a punch, a stripper into which the punch is inserted, and a die, comprising a load sensor for detecting the load applied to the punch, and a control unit for determining whether the clearance is appropriate based on the value detected by the load sensor, wherein the control unit determines that the clearance is not appropriate when the value detected by the load sensor exceeds a predetermined threshold. 【0111】 This configuration provides a determination device that can determine whether the clearance between the side of the punch and the inner wall of the hollow part of the stripper is appropriate. 【0112】 (Technology 2) The control unit determines whether the clearance is appropriate based on the load sensor's detection value from the time the punch starts moving from the top dead center towards the bottom dead center until the punch reaches the bottom dead center and then returns to the top dead center again, according to the determination device of Technology 1. 【0113】 This configuration allows for a more accurate determination of whether the clearance between the punch and the stripper is appropriate. 【0114】 (Technology 3) The control unit is a determination device according to technology 1 or 2, which determines whether the clearance is appropriate based on the load sensor's detection value when the punch is moved while the press die is not mounted on the press working device. 【0115】 This configuration allows for proper clearance to be maintained before the press die is mounted on the press working machine. 【0116】 (Technology 4) The control unit determines whether the clearance is appropriate based on the load sensor's detected value for a predetermined period from when the punch begins moving from the top dead center to the bottom dead center until the punch reaches the bottom dead center and returns to the top dead center again, according to the determination device of Technology 3. 【0117】 This configuration allows for a more accurate determination of whether the clearance between the punch and the stripper is appropriate. 【0118】 (Technology 5) The control unit is a determination device according to Technology 1 or 2, which determines whether the clearance is appropriate based on the value detected by the load sensor when the punch is moved while the press die is mounted on the press working machine and the workpiece is placed on the die. 【0119】 This configuration allows for the determination of whether the clearance between the punch and the stripper is appropriate during production. Therefore, if it is discovered during production that the clearance is not appropriate, early intervention is possible, thereby improving production efficiency. 【0120】 (Technology 6) The control unit is a determination device according to Technology 5, which determines whether the clearance is appropriate based on the load sensor's detection value from the moment the stripper and die come into contact through the workpiece until the punch comes into contact with the workpiece. 【0121】 This configuration allows for the determination of the appropriateness of the clearance between the punch and the stripper, while eliminating the influence of the workpiece. 【0122】 (Technology 7) The control unit is a determination device according to technology 5 or 6, which determines whether the clearance is appropriate based on the load sensor's detection value from the time the punch punches out the workpiece and leaves the workpiece until it returns to the top dead center. 【0123】 This configuration minimizes the influence of the workpiece when determining whether the clearance between the punch and the stripper is appropriate. 【0124】 (Technology 8) The load sensor is a determination device that includes multiple load sensors, one of the technologies 1 to 7. 【0125】 This configuration allows for more accurate determination of whether the clearance between the punch and the stripper is appropriate. 【0126】 (Technology 9) The judgment device of Technology 8 has multiple load sensors arranged at equal intervals on the side of the punch opposite the pressing surface. 【0127】 This configuration allows for the identification of areas where the clearance is inadequate. 【0128】 (Technology 10) The control unit is a determination device according to technology 8 or 9, which identifies the location of a portion of the punch's side surface where the clearance is not appropriate, based on the detection values ​​of multiple load sensors. 【0129】 This configuration makes it easy to adjust the clearance between the punch and the stripper. 【0130】 (Technology 11) A method for determining whether the size of the clearance between the side of the punch and the inner wall of the hollow portion of the stripper is appropriate in a press die having a punch, a stripper into which the punch is inserted, and a die, the method comprising: detecting a load applied to the punch; and determining whether the clearance is appropriate based on the detected load, wherein the step of determining whether the clearance is appropriate includes determining that the clearance is not appropriate if the detected load exceeds a predetermined threshold. 【0131】 This configuration provides a determination method that can determine whether the clearance between the side of the punch and the inner wall of the hollow part of the stripper is appropriate. 【0132】 (Technology 12) A press working apparatus comprising a punch, a stripper into which a hollow section is formed into which the punch is inserted, a die, and a determination device according to one of the technologies 1 to 10. 【0133】 This configuration makes it possible to provide a press working apparatus that can determine whether the clearance between the side of the punch and the inner wall of the hollow part of the stripper is appropriate. [Industrial applicability] 【0134】 The determination device, determination method, and press working apparatus of this disclosure are useful for determining whether the clearance between the punch and the stripper in a press die is appropriate when punching out any workpiece used for home appliances or medical devices, etc. [Explanation of symbols] 【0135】 1 punch 1a Press surface 1b side 2 Dies 2a Hollow part 3 Strippers 3a Hollow part 4 Stripper Plate 5 Die Plates 6. 60 load sensor 7 Stripper bolts 8 Stripper guide pins 9 Stripper guide bush 10 Stripper Guide Bushings 11 Position Sensor 12 Control Unit 13 Sensor Controller 14 Arithmetic section 15 Judgment section 16 Output section 17 Press Controller 18 Pressing device body 19 Servo motor 20 slides 21 Bolster 22. Object to be processed 23 Spring 24 Screw Plugs 25 Upper stopper 26 Lower stopper 27 Punch Plate 28 Backing Plates 29 Upper Die Set 30 Dibacking Plates 31 Lower Die Set 32 blocks 100 Judgment device 101 Upper mold 102 Lower mold 150 press dies 200 Pressing machine

Claims

[Claim 1] A determination device for determining whether the size of the clearance between the side surface of the punch and the inner wall of the hollow portion of the stripper is appropriate in a press die having a punch, A load sensor for detecting the load applied to the punch, A control unit that determines whether the clearance is appropriate based on the detected value of the load sensor, Equipped with, The control unit determines that the clearance is not appropriate when the detected value of the load sensor exceeds a predetermined threshold. Judgment device. [Claim 2] The control unit determines whether the clearance is appropriate based on the load sensor's detection value from the time the punch begins moving from the top dead center towards the bottom dead center until the punch reaches the bottom dead center and then returns to the top dead center. The determination device according to claim 1. [Claim 3] The control unit determines whether the clearance is appropriate based on the value detected by the load sensor when the punch is moved while the press die is not mounted on the press working device. The determination device according to claim 2. [Claim 4] The control unit determines whether the clearance is appropriate based on the detected value of the load sensor during a predetermined period from when the punch begins to move from the top dead center towards the bottom dead center until the punch reaches the bottom dead center and then returns to the top dead center. The determination device according to claim 3. [Claim 5] The control unit determines whether the clearance is appropriate based on the value detected by the load sensor when the punch is moved while the press die is mounted on the press working device and the workpiece is placed on the die. The determination device according to claim 2. [Claim 6] The control unit determines whether the clearance is appropriate based on the load sensor's detection value from the time the stripper and the die come into contact via the workpiece until the punch comes into contact with the workpiece. The determination device according to claim 5. [Claim 7] The control unit determines whether the clearance is appropriate based on the value detected by the load sensor from the time the punch punches out the workpiece and leaves the workpiece until it returns to the top dead center. The determination device according to claim 5. [Claim 8] The load sensor includes a plurality of load sensors, The determination device according to claim 1. [Claim 9] The plurality of load sensors are arranged at equal intervals on the side of the punch opposite to the pressing surface. The determination device according to claim 8. [Claim 10] The control unit identifies the location of the portion of the side surface of the punch where the clearance is not appropriate, based on the detected values ​​of the plurality of load sensors. The determination device according to claim 8. [Claim 11] A method for determining whether the clearance between the side surface of the punch and the inner wall of the hollow portion of the stripper is appropriate in a press die having a punch, a stripper into which the punch is inserted, and a die, A step of detecting the load applied to the punch, A step of determining whether the clearance is appropriate based on the detected load, Includes, The step of determining whether the clearance is appropriate includes determining that the clearance is not appropriate if the detected load exceeds a predetermined threshold. Judgment method. [Claim 12] A punch and A stripper having a hollow section into which the punch is inserted, Dai and, A determination device according to any one of claims 1 to 10, Equipped with, Pressing machine.

Images