Press forming control device, press forming control method, and press forming control program

Abstract

This invention provides a press forming control device, a press forming control method, and a press forming control program that can prevent line misalignment in press forming by utilizing electromagnets. [Solution] A press forming control device comprising a press die containing an electromagnet and a control unit that controls the energization of the electromagnet, wherein one or more electromagnets are arranged in the press die at locations corresponding to the processing shape of the workpiece, and the control unit comprises a prediction unit that performs a simulation of press processing of the workpiece using the press die and predicts the positional displacement of the workpiece when the press die presses and forms the workpiece, and an excitation control unit that, after the workpiece comes into contact with a protrusion of the press die, supplies current to the electromagnet built into the press die to excite it and attract the workpiece to the press die.

Description

Technical Field

[0001] The present invention relates to a press forming control device, a press forming control method, and a press forming control program.

Background Art

[0002] In the forming of press products, mold repairs due to line misalignment defects often occur. Among the formed shapes when steel plates used for vehicle bodies are press processed, linear formed shapes are called feature lines, feature ridges, or character lines. In recent years, as one of the designs that give a sharp and sophisticated impression to vehicles, the forming of character lines with R1 - R5, which are smaller than the conventional character lines with a radius of curvature R of 6 or more, has been increasing. When forming character lines with small R1 - R5, line misalignment defects are likely to occur. As conventional techniques for solving the defects that occur during such bending and press processing, there are techniques such as making the gap between the mold less than the plate thickness, that is, making it a hard hit to blur the unevenness, adjusting the balance of the inflow amount sandwiching the character line to make it difficult to shift, increasing the radius of curvature of the character line during shape forming, and forming the character line smaller in a later process. Furthermore, techniques using electromagnets are disclosed (see Patent Documents 1 to 4).

[0003] Patent Document 1 discloses a technique of providing an electromagnet in a press mold and functioning the electromagnet during processing to fix the workpiece. Patent Document 2 discloses a technique of providing an electromagnet in a die holder for supporting a workpiece in press processing, functioning the electromagnet during processing to fix the workpiece, and turning off the electromagnet when the processing is completed. Patent Document 3 discloses a technique of providing an electromagnet in a workpiece fixing means for press processing, functioning the electromagnet during processing to fix the workpiece, and removing the workpiece by eliminating the magnetism when the processing is completed. Patent Document 4 discloses a technique of providing an electromagnet in a seat for placing and fixing a material in a press processing method and fixing it with magnetic force.

Prior Art Documents

Patent Documents

[0004] [Patent Document 1] Japanese Patent Publication No. 2007-283340 [Patent Document 2] Japanese Patent Application Publication No. 10-192985 [Patent Document 3] Japanese Patent Application Publication No. 05-007938 [Patent Document 4] Japanese Patent Publication No. 2006-051547 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] However, methods that use strong pressure to blur unevenness caused by line misalignment may not completely eliminate the unevenness. Methods that involve adjusting the balance of the amount of material flowing between the character have limitations due to adjustments for molding defects caused by cracks and wrinkles, and constraints imposed by the product shape. In methods where the radius of curvature of the character is increased during shape molding, and the character is molded smaller in a later process, it is necessary to include a molding punch for the character part in the mold structure of the later process, which increases mold costs. Furthermore, although technologies using electromagnets have been disclosed (see Patent Documents 2 to 4), the technologies disclosed in Patent Documents 2 to 4 are not sufficiently suitable for preventing line misalignment when molding characters with small R1 to R5, and Patent Documents 1 and 4 do not disclose the point of turning off the electromagnet after processing.

[0006] In view of the above problems, the present invention aims to provide a press forming control device, a press forming control method, and a press forming control program that can prevent line misalignment in press forming by utilizing an electromagnet. [Means for solving the problem]

[0007] A first aspect of the present invention is a press forming control device comprising a press die containing electromagnets and a control unit for controlling the energization of the electromagnets, wherein one or more electromagnets are arranged in the press die at locations corresponding to the processing shape of the workpiece, and the control unit comprises a prediction unit that performs a simulation of press processing of the workpiece using the press die and predicts the positional displacement of the workpiece when the press die presses and forms the workpiece, and an excitation control unit that, after the workpiece comes into contact with a protrusion of the press die, supplies current to the electromagnets built into the press die to excite them and attract the workpiece to the press die.

[0008] In a first embodiment of the present invention, the control unit may determine the timing of supplying current to the electromagnet based on a prediction.

[0009] In a first embodiment of the present invention, the control unit may determine the intensity of the current supplied to the electromagnet based on a prediction.

[0010] In a first embodiment of the present invention, the electromagnet may be installed inside the protrusion of the press die.

[0011] In the first embodiment of the present invention, multiple electromagnets may be arranged in a row in the press die.

[0012] In a first embodiment of the present invention, a detection unit may be further provided for detecting contact between the workpiece and the protrusion of the press die.

[0013] A second aspect of the present invention relates to a press forming control device comprising a press die containing an electromagnet and a control unit for controlling the energization of the electromagnet, wherein one or more electromagnets are arranged in the press die at locations corresponding to the processing shape of the workpiece, and the control unit performs a simulation of press processing of the workpiece using the press die to predict the displacement of the workpiece when the press die presses and shapes the workpiece, and an excitation control step, after the workpiece comes into contact with a protrusion of the press die, supplies current to the electromagnets built into the press die to excite them based on the prediction and cause the workpiece to be attracted to the press die.

[0014] A third aspect of the present invention is a press forming program for a press forming control device comprising a press die containing an electromagnet and a control unit for controlling the energization of the electromagnet, wherein one or more electromagnets are arranged in the press die at locations corresponding to the processing shape of the workpiece, and the control unit implements a prediction function that performs a simulation of press processing of the workpiece using the press die to predict the displacement of the workpiece when the press die presses and forms the workpiece, and an excitation control function that, after the workpiece comes into contact with a protrusion of the press die, supplies current to the electromagnet built into the press die to excite it and attract the workpiece to the press die.

[0015] According to the present invention, a press forming control device, a press forming control method, and a press forming control program can be provided that can prevent line misalignment in press forming by utilizing an electromagnet. [Brief explanation of the drawing]

[0016] [Figure 1] This is a schematic diagram showing the molding lines present on the surface of an automobile body. [Figure 2] These are cross-sectional views of a mold and a sheet metal. Figure 2(a) illustrates the normal molding process, while Figure 2(b) illustrates the occurrence of line misalignment in the sheet metal. [Figure 3] It is a schematic diagram of an example of a press forming control device according to this embodiment. [Figure 4] It is a block diagram showing a configuration example of a control unit of a press forming control device according to this embodiment. [Figure 5] It is a diagram for explaining the timing of power supply from a power supply unit to an electromagnet. Fig. 5(a) is a diagram at the time when the object to be processed hits the convex portion, Fig. 5(b) is a diagram in which the forming of the object to be processed progresses and contacts the surface of the object to be processed at the convex portion 37 and conforms to the R of the mold, and Fig. 5(c) is a diagram in which deformation has occurred in the object to be processed. [Figure 6] Fig. 6(a) is a diagram showing an example of a press mold, and Fig. 6(b) is a diagram showing a state in which an object to be processed is applied to the press mold shown in Fig. 6(a). [Figure 7] It is a flowchart for explaining a press forming control method using the press forming control device according to the embodiment.

Embodiments for Carrying Out the Invention

[0017] Next, embodiments of the present invention will be described with reference to the drawings. In the description of the drawings according to the embodiments, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic, and the relationships such as the relationship with the planar dimensions are different from the actual ones. Therefore, specific dimensions should be determined in consideration of the following description. Also, it is a matter of course that there are parts where the dimensional relationships and ratios are different between the drawings.

[0018] Also, the embodiments illustrate devices and methods for embodying the technical idea of the present invention, and the technical idea of the present invention does not specify the configurations, arrangements, layouts, etc. of each component as the following. The technical idea of the present invention can be variously modified within the technical scope defined by the claims described in the claims.

[0019] (Embodiment) The press forming control device according to this embodiment is intended for forming shapes on the surface of an automobile body, particularly shapes with small radii of curvature R, such as R1 to R5, in the parts that bend during forming. An example of a forming shape with a small radius of curvature is shown in Figure 1. Figure 1 shows forming lines present on the surface of an automobile 10 as the workpiece. The smaller the radius of curvature of the forming lines 11 and 12 passing through the hood and the forming line 13 passing through the fender, the sharper the shape appears, giving the user a sharp impression.

[0020] Figure 2 shows a cross-sectional view of the mold 22 and the sheet metal 21. The cross-sectional view of the mold 22 and the sheet metal 21 shown in Figure 2 is, as an example, a cross-sectional view perpendicular to the direction of the line when forming the forming line 11. When forming a forming line as shown in Figure 1, the sheet metal 21 is pressed against the convex portion 25 of the mold 22 and the sheet metal 21 is bent in the direction of the arrow 23 to perform the forming, as shown in Figure 2(a).

[0021] However, if the radius of curvature of the forming line 11 is small, as shown in Figure 2(b), the protrusion 25 of the mold 22 comes into contact with the iron plate 21, and due to the balance of tension between the part of the iron plate 21 that is in contact with the protrusion 25 and the surrounding part, the part of the iron plate 21 that has been given a convex shape by the protrusion 25 may shift away from the protrusion 25, which can cause linear irregularities 26 to occur near the protrusion 25 of the iron plate 21. These linear defects 26 are called linear misalignments.

[0022] The press forming control device according to this embodiment is equipped with an electromagnet inside the protrusion 25 of the mold 22 to prevent misalignment that may occur when forming a shape with such a small radius of curvature. During forming, the electromagnet is energized to hold the iron plate 21 to the mold 22, preventing the iron plate 21 from shifting. The press forming control device according to this embodiment allows the iron plate 21 to be removed from the mold 22 by stopping the power supply to the electromagnet after forming to demagnetize it.

[0023] Figure 3 shows a schematic diagram of an example of a press forming control device according to this embodiment. The press forming control device 30 shown in Figure 3 consists of an electromagnet 31 and a control unit 32. The electromagnet 31 is built into the protrusion 37 of the press die 33. The control unit 32 consists of a prediction unit 35, an excitation control unit 34, and a power supply unit 36.

[0024] The power supply unit 36 ​​is connected to the electromagnet 31 and supplies current to the electromagnet 31. The excitation control unit 34 is connected to the power supply unit 36 ​​and controls the on / off state and / or the strength of the current supplied from the power supply unit 36 ​​to the electromagnet 31.

[0025] The workpiece 38 is, for example, a steel sheet that makes up the body of an automobile, such as a ferritic or martensitic stainless steel sheet, which in this embodiment is formed by a press die 33. The press forming control device according to this embodiment is a device that can attract the workpiece 38 to the press die 33 by the magnetism of the electromagnet 31, and therefore the workpiece 38 is made of a material that is attracted to a magnet by magnetic force.

[0026] Figure 4 shows an example configuration of the control unit of the press forming control device according to this embodiment. As shown in Figure 4, the control unit 32 of the press forming control device according to this embodiment consists of a CPU 41 for executing various calculations, a storage unit 42 for storing processing programs, data, etc., an I / O (input / output interface) 43, a display unit 44, an input unit 45, and a power supply unit 36.

[0027] I / O43 is an interface, buffer, etc., for communication (transmitting and receiving).

[0028] The display unit 44 is a display device such as a display, and displays the calculation results from the CPU 41.

[0029] The input unit 45 is an input device such as a keyboard or mouse, which receives input from the user and transmits it to the CPU 41.

[0030] Figure 4 shows the block diagram of the CPU 41. When each function of the CPU 41 is implemented by software, the CPU 41 implements each function by executing instructions of the program, which is the software that implements each function. Specifically, it includes an excitation control unit 34 and a prediction unit 35. The storage unit 42 also includes a prediction data storage unit 421.

[0031] As will be described later, the prediction unit 35 performs a simulation of press working of a workpiece using a press die based on CAD data of the die and the steel sheet to be formed, and predicts the positional displacement of the workpiece when the press die presses the workpiece to form it.

[0032] The prediction data storage unit 421 stores the results of the simulation performed by the prediction unit 35 as prediction data.

[0033] Referring to Figure 5, the timing of power supply from the power supply unit 36 ​​to the electromagnet 31 will be explained. As shown in Figure 5(a), from the state in which the workpiece 38 contacts the convex portion 37 of the press die 33 until a predetermined state in which no line misalignment occurs in the workpiece 38, power is not supplied to the electromagnet 31 and the electromagnet 31 is not energized (electromagnet 31 is OFF). During this time, as shown in Figure 5(b), the workpiece 38 is bent toward the convex portion 37 of the press die 33, and at the timing when the workpiece 38 reaches a predetermined state in which no line misalignment occurs, the power supply unit 36 ​​supplies power to the electromagnet 31 before line misalignment occurs, the electromagnet 31 is energized (electromagnet 31 is ON), and the workpiece 38 is attracted to the convex portion 37 of the press die 33 by the electromagnet 31 as shown by the arrow in the figure.

[0034] As shown in Figure 5(c), if the power supply unit 36 ​​supplies power to the electromagnet 31 during a predetermined period between the state in which the workpiece 38 hits the protrusion 37 and the state in which no line misalignment occurs in the workpiece 38, the electromagnet 31 is energized, and the workpiece 38 is attracted to the protrusion 37, deformation such as bending may occur in the part of the workpiece 38 enclosed by the dashed line 501. Therefore, after the workpiece 38 hits the protrusion 37 and the workpiece 38 is formed to a predetermined shape by the protrusion 37 of the press die 33, the electromagnet 31 is energized to attract the workpiece 38 to the protrusion 37.

[0035] The predetermined shape formed by shaping the workpiece 38 from the moment it strikes the protrusion 37 until the electromagnet 31 is energized and the workpiece 38 is attracted to the protrusion 37 depends on the shape of the press die 33, the strength, material, and thickness of the workpiece 38, and the bending speed of the workpiece 38. Therefore, the predetermined shape formed by shaping the workpiece 38 from the moment the electromagnet 31 is energized and the workpiece 38 is attracted to the protrusion 37, without deformation of the workpiece 38 or misalignment of the lines, is calculated in advance by simulation, and during actual molding, the power supply unit 36 ​​supplies power to the electromagnet 31 based on the results of the simulation.

[0036] This simulation is a standard simulation for evaluating cracks, wrinkles, defects, etc., in press forming, and may be a CAE (Computer-Aided Engineering) analysis such as press working analysis. The simulation method involves, for example, creating a CAE model and then performing forming analysis using the created CAE model. Specifically, for example, a 3D model of the workpiece is created using CAD, the created model is meshed, and then the forming material, forming conditions, etc., are set using deformation and stress concentration mechanical models, and the analysis is performed. The processing deformation and stress deformation are calculated from this simulation, and these results are used.

[0037] As described above, when the workpiece 38 is attracted to the protrusion 37, the electromagnet 31 may be excited at a timing when no deformation occurs in the workpiece 38 and no line misalignment occurs. Alternatively, the strength of the magnetic field generated may be adjusted by adjusting the strength of the current supplied to the electromagnet 31 so that when the workpiece 38 is attracted to the protrusion 37, no deformation occurs in the workpiece 38 and no line misalignment occurs. The strength of the current supplied to the electromagnet may also be determined by the simulation described above.

[0038] The prediction unit 35 executes the simulation described above. The prediction unit 35 may store the results of the executed simulation as prediction data in the prediction data storage unit 421. The excitation control unit 34 may receive the results of the simulation executed by the prediction unit 35 directly from the prediction unit 35, or it may read out the prediction data that the prediction unit 35 has previously executed a simulation for and stored in the prediction data storage unit 421, and determine the timing for exciting the electromagnet.

[0039] When applying the press forming control device according to this embodiment to the forming of a forming line 11, as shown in Figure 1, electromagnets are arranged along the forming line 11. Figure 6(a) shows an example of a press die 60 for forming the forming line 11. The press die 60 is equipped with a line-shaped protrusion 601 with a small radius of curvature. The electromagnets are installed inside the protrusion 601.

[0040] Figure 6(b) shows the state in which the workpiece 602 is applied to the press die 60 shown in Figure 6(a) from the front relative to the plane of the paper, and the forming line B is being formed by the protrusion 601. Part of the forming line 603 indicated by B has been formed by a portion of the protrusion 601, but the workpiece 602 has not yet made contact with the remaining portion of the protrusion 601, and a space A is created between the protrusion 601 and the workpiece 602.

[0041] As described above, the timing at which the workpiece 602 makes contact may differ depending on the location of the protrusion 601. Therefore, if all the electromagnets installed inside the protrusion 601 are energized at the same time, deformation such as bending may occur in the workpiece 602. To address this, multiple electromagnets may be installed inside the protrusion 601, and the timing of energizing each electromagnet may be varied for each part of the protrusion 601. The excitation timing of each of the multiple electromagnets installed inside the protrusion 601 is calculated by the simulation described above. The multiple electromagnets installed inside the protrusion 601 may be arranged in a line to match the line shape of the protrusion 601.

[0042] Furthermore, the arrangement of each of the multiple electromagnets installed inside the protrusion 601 may also be determined using the results of the simulation described above. Electromagnets are placed inside the protrusion 601 to suppress displacement of the workpiece 602 during molding. However, if an electromagnet installed in the area where space A is created, as shown in Figure 6(b), is energized, there is a concern that abnormal deformation may occur due to forcibly attracting the workpiece 602 to the protrusion 601. In such a case, possible countermeasures include weakening the magnetic force used to energize the electromagnet installed in the area where space A is created, installing the electromagnet at a deep position away from the surface of the protrusion 601, not installing an electromagnet, or delaying the timing of energization compared to the electromagnet installed in the area indicated by B.

[0043] The control unit 32 of the press forming control device according to this embodiment, shown in Figure 4, may further include a detection unit for detecting contact between the workpiece and the protrusion of the press die. Based on the prediction result from the prediction unit 35 and the detection result of the contact state of the workpiece with the protrusion by the detection unit, the timing for exciting the electromagnet installed inside the protrusion may be determined.

[0044] The detection unit may be, for example, one or more pressure sensors installed on the surface of the press die or inside near the surface. Alternatively, the detection unit may be, for example, an optical sensor that detects the relative positional relationship between the workpiece and the press die.

[0045] The press forming control method according to this embodiment will be explained using the flowchart shown in Figure 7. Figure 7 is a flowchart illustrating the procedure for the press forming control method according to this embodiment, which performs a simulation of press forming of a workpiece using a press die and causes the workpiece to be attracted to the press die.

[0046] As shown in Figure 7, the press forming control method according to this embodiment includes a prediction step (step S701) and an excitation control step (step S702).

[0047] In step S701, the prediction unit performs a simulation of press working of a workpiece using a press die and predicts the positional displacement of the workpiece when the press die presses and shapes the workpiece.

[0048] In step S702, after the workpiece comes into contact with the protrusion of the press die, the excitation control unit supplies current to the electromagnet built into the press die based on the prediction, thereby exciting the workpiece and causing it to be attracted to the press die.

[0049] As stated above, the present invention naturally includes various embodiments and the like that are not described herein. Therefore, the technical scope of the present invention is determined solely by the inventive features relating to the claims that are reasonable based on the above description. [Explanation of Symbols]

[0050] 10. Automobiles 11, 12, 13, 603 molding lines 21 Iron Plate 22 molds 23, 24 Arrows 25, 37, 601 protrusions 26. Line misalignment 30 Press forming control device 31 Electromagnet 32 Control Unit 33, 60 Press molds 34 Excitation Control Unit 35 Prediction Section 36 Power supply section 38,602 Objects to be processed 41 CPU 42 Storage section 43 I / O (Input / Output Interface) 44 Display section 45 Input section 421 Prediction data storage unit 501 Dashed line

Claims

1. A press molding control device comprising a press die containing an electromagnet and a control unit for controlling the energization of the electromagnet, The aforementioned press die has one or more electromagnets arranged in locations corresponding to the processing shape of the workpiece. The control unit, A prediction unit that performs a simulation of press working of a workpiece using the aforementioned press die and predicts the positional displacement of the workpiece when the press die presses and shapes the workpiece, The system includes an excitation control unit that, after the workpiece comes into contact with a protrusion of the press die, supplies current to an electromagnet built into the press die to excite it based on the prediction, thereby attracting the workpiece to the press die. A press molding control device characterized by the following:

2. The press molding control device according to claim 1, wherein the control unit determines the timing for supplying current to the electromagnet based on the prediction.

3. The press molding control device according to claim 1, wherein the control unit determines the intensity of the current supplied to the electromagnet based on the prediction.

4. The press molding control device according to claim 1, wherein the electromagnet is installed inside the protrusion of the press die.

5. The press molding control device according to claim 1, wherein multiple electromagnets are arranged in a row in the press die.

6. The press molding control device according to claim 1, further comprising a detection unit for detecting contact between the workpiece and the protrusion of the press die.

7. A press forming control method in a press forming control device comprising a press die containing an electromagnet and a control unit for controlling the energization of the electromagnet, The aforementioned press die has one or more electromagnets arranged in locations corresponding to the processing shape of the workpiece. The control unit, A prediction step involves performing a simulation of press working of a workpiece using the aforementioned press die to predict the positional displacement of the workpiece when the press die presses and shapes the workpiece, and After the workpiece comes into contact with the protrusion of the press die, an excitation control step is performed in which current is supplied to an electromagnet built into the press die based on the prediction to excite it and cause the workpiece to be attracted to the press die. A press forming control method that performs this operation.

8. A press forming control program for a press forming control device comprising a press die containing an electromagnet and a control unit for controlling the energization of the electromagnet, The aforementioned press die has one or more electromagnets arranged in locations corresponding to the processing shape of the workpiece. The control unit, A prediction function that performs a simulation of press working of a workpiece using the aforementioned press die and predicts the positional displacement of the workpiece when the press die presses and shapes the workpiece, After the workpiece comes into contact with the protrusion of the press die, an excitation control function supplies current to an electromagnet built into the press die based on the prediction to excite it and cause the workpiece to be attracted to the press die. A press forming control program that makes this possible.

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