Forming process
By using a non-contact heating coil configuration with opposite current directions on the open punched end face of the steel plate, the problem of low heating efficiency in the prior art is solved, and a more efficient and stable heating effect is achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- TOYOTA JIDOSHA KK
- Filing Date
- 2023-06-19
- Publication Date
- 2026-07-03
AI Technical Summary
In the prior art, when heating the open punched end face of a steel plate using a ring heating coil, the current density decreases, resulting in reduced heating efficiency.
The heating coils are arranged in a non-contact state along the open punching end face, and the current direction is opposite. The open punching end face of the steel plate is heated by induced electromotive force, and the position and shape of the heating coils are optimized to increase the current density.
It improves the heating efficiency of the open punching end face, enhances the current density, and ensures the stability and uniformity of heating.
Smart Images
Figure CN117259587B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a forming process for forming steel plates. Background Technology
[0002] One of the challenges in stamping high-strength materials is tensile flange fracture. This fracture is caused by residual deformation of the sheared end faces, such as the blanking end, resulting from the blanking process.
[0003] As a method to reduce the residual deformation, the following forming process is proposed: a ring-shaped heating coil is configured to be in a non-contact state with the end face of the punched end produced by the punching process and opposite to the end face, and an induced electromotive force is generated in the steel plate by flowing an alternating current through the heating coil, thereby heating the end face (for example, see Japanese Patent Application Laid-Open No. 2022-108601). Summary of the Invention
[0004] However, when heating the end face of a partially open punched end of a steel plate using the aforementioned annular heating coil, although current flows through the end face, this current leaves the end face and disperses inside the steel plate, flowing in the opposite direction to form a ring. Consequently, the current density at the end face may decrease, leading to a decrease in heating efficiency.
[0005] This invention was made to solve this problem, and its main purpose is to provide a forming process method that can improve the heating efficiency of the end face of the open punching end.
[0006] One aspect of the present invention for achieving the above-mentioned objective is a forming process method, comprising:
[0007] The blanking process involves blanking a steel plate to form an open blanking end, which is a portion of the plate's end face that is now exposed.
[0008] In the heating process, the heating coil is configured to be in a non-contact state along the end face of the open punched end generated in the aforementioned punching process, and to clamp the end face of the open punched end. By allowing alternating current to flow through the aforementioned heating coil, an induced electromotive force is generated in the aforementioned steel plate, thereby heating the end face of the aforementioned open punched end.
[0009] The current direction of the heating coil disposed on one side of the end face of the aforementioned open punching end is opposite to the current direction of the heating coil disposed on the other side of the end face of the aforementioned open punching end.
[0010] In this approach, it is also possible that...
[0011] In the aforementioned heating process,
[0012] The heating coil on one side of the end face of the aforementioned open punching end is disposed on the aforementioned open side.
[0013] The heating coil on the other side of the aforementioned open punching end is disposed on the aforementioned steel plate side.
[0014] In this approach, it is also possible that...
[0015] In the aforementioned heating process,
[0016] The heating coil on one side is positioned on the upper side, and the heating coil on the other side is positioned on the lower side.
[0017] In the aforementioned cross-sectional views of the heating coils on the open punching end, upper side, and lower side,
[0018] Viewed from above and below, the cross-section of the aforementioned upper heating coil does not overlap with the cross-section of the aforementioned open punching end, while the cross-section of the aforementioned lower heating coil overlaps with the cross-section of the aforementioned open punching end.
[0019] In this approach, it is also possible that...
[0020] The aforementioned upper heating coil is positioned within a suitable rectangular area on the upper side, defined by length a and width b.
[0021] The aforementioned lower heating coil is positioned within a suitable rectangular area on the lower side, defined by the length (c) and width (d).
[0022] The aforementioned suitable upper range is defined starting from the upper corner of the end face of the aforementioned open punching end.
[0023] The aforementioned suitable lower side range is set starting from a position α, which is a predetermined distance α from the lower side corner of the end face of the aforementioned open punching end.
[0024] Let the diameter of the aforementioned upper and lower heating coils be D, satisfying the following relationship:
[0025] 0≤a≤1.5×D
[0026] 0≤b≤1.5×D
[0027] α≤c≤1.2×D
[0028] 0 ≤ d ≤ 1.5 × D.
[0029] In this approach, it is also possible that...
[0030] It also includes: a forming process, which, relative to the aforementioned open punching end, shapes the stretch flange.
[0031] The distance from the central axis of the heating coil disposed on the stretching side of the aforementioned steel plate in the aforementioned forming process to the end face of the aforementioned open punching end is closer than the distance from the central axis of the heating coil disposed on the side opposite to the stretching side to the end face of the aforementioned open punching end.
[0032] In this approach, it is also possible that...
[0033] In the aforementioned heating process, the steel plate, after being punched in the aforementioned punching process, is placed in the heating fixture and then heated by the aforementioned heating coil.
[0034] The aforementioned heating fixture includes: a positioning guide for holding the steel plate after it has been punched through the aforementioned punching process, used to position the steel plate in a specified position; and the aforementioned heating coil for heating the open punched end face of the steel plate positioned by the aforementioned positioning guide.
[0035] When the steel plate after being punched through the aforementioned punching process is placed on the aforementioned positioning guide, the aforementioned heating coil located on the front side is offset to the outside of the aforementioned steel plate.
[0036] In this approach, it is also possible that...
[0037] It also includes: a forming process, which, relative to the aforementioned open punching end, shapes the stretch flange.
[0038] In the aforementioned heating process, the aforementioned heating coil heats the curved flange forming part of the high-strength material skeleton component of the vehicle after it has been formed by the aforementioned forming process.
[0039] In this approach, it is also possible that...
[0040] The aforementioned heating process can be performed in any process of the stamping machine.
[0041] In this approach, it is also possible that...
[0042] It also includes: a forming process, which shapes the stretch flange relative to the aforementioned punching end.
[0043] The aforementioned heating process is performed during the idling process of adjusting the conveying distance when the aforementioned steel plate is conveyed from the aforementioned punching process to the aforementioned forming process.
[0044] In this approach, it is also possible that...
[0045] Inside the aforementioned stamping press, the steel sheet forming product is continuously conveyed by the holding part, and at the same time, at least the aforementioned blanking process and the aforementioned idle process are continuously performed at a specified conveying interval.
[0046] By arranging a heating fixture containing the aforementioned heating coil at a position corresponding to the aforementioned idling process, the aforementioned idling process is replaced by the aforementioned heating process.
[0047] According to the present invention, a forming process method is provided that can improve the heating efficiency of the end face of the open punching end.
[0048] The above and other objects, features and advantages of this disclosure will be more fully understood from the detailed description and accompanying drawings given below, which are given by way of example only and should not be considered as limiting the disclosure. Attached Figure Description
[0049] Figure 1 This is a schematic diagram that roughly illustrates the steps of the forming process involved in this embodiment.
[0050] Figure 2 This is a schematic diagram that roughly illustrates the heating process.
[0051] Figure 3 This is a perspective view showing the heating coil involved in this embodiment.
[0052] Figure 4 This is a top view obtained by observing the heating coil involved in this embodiment from above.
[0053] Figure 5 This is a cross-sectional view of the heating coil positioned at the open punching end being cut vertically.
[0054] Figure 6 This is a diagram showing the magnetic field strength at the open punching end.
[0055] Figure 7 This is a graph showing the current density at the open punching end.
[0056] Figure 8 This is a diagram showing a suitable configuration of the heating coils on the upper and lower sides.
[0057] Figure 9 This is a diagram showing the configuration of the open punched end of the steel plate relative to the heating coil of the heating fixture.
[0058] Figure 10 This diagram shows a configuration with two heating coils arranged on the upper side and two heating coils arranged on the lower side.
[0059] Figure 11 This diagram shows the configuration where the upper coil overlaps with the lower coil when viewed from above.
[0060] Figure 12 This is a diagram showing the heating results when heating is performed using a conventional heating coil and the heating coil involved in this embodiment.
[0061] Figure 13 This is a graph showing the relationship between the heating coils on the upper and lower sides and the temperature distribution, which is the result of the experiment.
[0062] Figure 14 This is a diagram showing a molded article containing a stretch flange forming portion.
[0063] Figure 15 This is a diagram showing a specific example of a molded part of the FR lower arm.
[0064] Figure 16 This is a diagram showing a specific example of a molded part of the lower part of column A.
[0065] Figure 17 This is a diagram showing a specific example of a molded part on the lower outer side of the B-pillar.
[0066] Figure 18 This is a diagram showing an example of a heating fixture.
[0067] Figure 19 This diagram compares the steps of the forming process according to this embodiment with the steps of a conventional forming process.
[0068] Figure 20 This is a diagram illustrating an example of the processes within a stamping press. Detailed Implementation
[0069] The present invention will now be described through embodiments thereof, but the invention as described in the claims is not intended to be limited to these embodiments. Furthermore, the configurations described in the embodiments are not necessarily essential technical means for solving the problem.
[0070] Implementation Method 1
[0071] Figure 1 This is a schematic diagram that roughly illustrates the steps of the forming process according to this embodiment. In the forming process described below, an open punch end 101 with a portion of its end face open is formed on a steel plate 100, which is a workpiece, and the periphery of the open punch end 101 is deformed to form a stretch flange 102.
[0072] The forming process method involved in this embodiment is, for example, as follows: Figure 1 As shown, it includes: a blanking process, in which an open blanking end 101 is formed by blanking a steel plate; a heating process, in which the open blanking end 101 is heated; a cooling process, in which the heat generated in the heating process is cooled; and a forming process, in which a stretching flange 102 is formed relative to the open blanking end 101.
[0073] The blanking process is a process of blanking a steel plate 100 fixed to a die (not shown) using a punch (not shown). As described later in detail, the heating process is a process of heating the open blanking end 101 formed by the blanking process.
[0074] In the heating process, such as Figure 2As shown, the punched steel plate 100 is positioned on the positioning guide 3 of the heating fixture 200. Then, induction heating is performed on the open punched end 101 of the steel plate 100 using the heating coil 2. In this embodiment, high-frequency induction heating, for example, by flowing a high-frequency alternating current through the heating coil 2 to generate an induced electromotive force in the steel plate 100, is preferably performed. After heating using the heating coil 2, the steel plate 100 is removed from the heating fixture 200.
[0075] Furthermore, the heating temperature of the heating coil 2 is adjusted, for example, so that the stamping end 101 is below the Ac1 point of 200°C. Heating within this temperature range allows for the appropriate removal of residual deformation. In particular, when heated above the Ac1 point, the steel sheet 100 undergoes an austenitic phase transformation. If air cooling is performed, it softens and its strength decreases. If rapid cooling is performed using running water or the like, its hardness increases and its formability decreases during the forming process. Therefore, it is preferable to keep the temperature below the Ac1 point.
[0076] like Figure 1 As shown, the cooling process is a process of cooling the open blanking end 101 after it has been heated in the heating process. Specifically, the steel plate 100 is placed at room temperature for a certain period of time. Furthermore, in the forming process described in this embodiment, the cooling process may be omitted. In this case, the forming process described later is performed after the heating process. The forming process (flanging process) is a process in which the open blanking end 101 is plastically deformed using a flange die or the like to form the stretch flange 102.
[0077] Residual deformation generated at the periphery of the open blanking end 101 due to the blanking process is removed by a heating process. After cooling, it is introduced into the forming process. Therefore, compared with the case where the steel sheet 100 is heated, damage caused by flange dies, etc., can be reduced. Moreover, in this embodiment, as described later, the open blanking end 101 can be heated locally, so the heating efficiency is also good while the residual deformation can be removed well.
[0078] In the past, when the end face of the open punched end of a steel plate was heated by a ring-shaped heating coil, although current flowed on the end face, this current left the end face and dispersed inside the steel plate, flowing in the opposite direction to form a ring. As a result, the current density at the end face may decrease, leading to a decrease in heating efficiency.
[0079] Figure 3 This is a perspective view showing the heating coil involved in this embodiment. Figure 4 This is a top view obtained by observing the heating coil involved in this embodiment from above.
[0080] To address the aforementioned issues, in the heating step of the forming process according to this embodiment, for example... Figure 3 and Figure 4 As shown, the heating coil 2 is configured to be in a non-contact state with the end face 103 of the open punched end 101 generated in the punching process, and to clamp the end face 103 of the open punched end 101. Then, by allowing an alternating current to flow through the heating coil 2, an induced electromotive force is generated in the steel plate 100, thereby heating the end face 103 of the open punched end 101. Moreover, the current direction of the heating coil 21 disposed on one side (upper side) of the end face 103 of the open punched end 101 is opposite to the current direction of the heating coil 22 disposed on the other side (lower side) of the end face 103 of the open punched end 101.
[0081] Therefore, a current loop can be formed along the end face 103 of the open punching end 101, so that the current is concentrated on the end face 103. As a result, the current density at the end face 103 of the open punching end 101 can be increased, and the heating efficiency of the end face 103 can be improved.
[0082] Figure 5 This is a cross-sectional view of the heating coil positioned at the open punching end being cut vertically. In the heating process, such as... Figure 5 As shown, the heating coil 21 on the upper side of the end face 103 of the open punching end 101 is disposed on the open side, and the heating coil 22 on the lower side of the end face 103 of the open punching end 101 is disposed on the steel plate side.
[0083] Therefore, the open punching end 101 is clamped obliquely upward by the upper heating coil 21 and the lower heating coil 22, as... Figure 6 As shown, the magnetic field clamps the coils at an upward angle. Therefore, even if the upper and lower heating coils 21 and 22 deviate slightly from their set positions, stable heating can still be achieved. Furthermore, as... Figure 7 As shown, a strong current flows from the upper side corner 104 of the end face 103 of the open punching end 101, which can further improve the heating efficiency of the end face 103 of the open punching end 101.
[0084] Generally, when heating the open-faced end of the blanking end by clamping it between upper and lower heating coils, the temperature peak occurs directly below the upper and lower heating coils. Therefore, the position of the temperature peak changes when the relative position of the upper and lower heating coils to the open-faced end changes. Thus, managing their relative position is particularly important for concentrated heating of the open-faced end.
[0085] In contrast, in this embodiment, as described above, the open punching end 101 is sandwiched obliquely upward by the upper heating coil 21 and the lower heating coil 22. Therefore, the temperature peak begins at the upper corner 104 of the end face 103 of the open punching end 101, making the management of the relative positional relationship between the upper and lower heating coils 21, 22 and the end face 103 of the open punching end 101 less sensitive. Thus, even if this relative positional relationship changes slightly from the set relationship, the end face 103 of the open punching end 101 can be heated in a concentrated manner.
[0086] Next, the appropriate relative positional relationship between the upper and lower heating coils 21 and 22 and the end face 103 of the open punching end 101 will be described in detail. Figure 8 This is a diagram showing a suitable configuration of the heating coils on the upper and lower sides.
[0087] Preferably, such as Figure 8 As shown in the cross-sectional view of the open punching end 101 and the upper and lower heating coils 21 and 22, viewed from the top and bottom, the cross-section of the upper heating coil 21 does not overlap with the cross-section of the open punching end 101, while the cross-section of the lower heating coil 22 overlaps with the cross-section of the open punching end 101. Therefore, the open punching end 101 is held obliquely upward by the upper heating coil 21 and the lower heating coil 22, ensuring stable heating even if the upper and lower heating coils 21 and 22 deviate slightly from their set positions.
[0088] Preferably, the upper heating coil 21 is disposed within a rectangular upper suitable range X1 with vertical length a and horizontal width b, and the lower heating coil 22 is disposed within a rectangular lower suitable range X2 with vertical length c and horizontal width d.
[0089] The upper suitable range X1 is set upward and to the left, starting from the upper corner 104 of the end face 103 of the open punching end 101. The lower suitable range X2 is set downward and to the right, starting from a position at a predetermined distance α away from the lower corner 105 of the end face 103 of the open punching end 101.
[0090] Furthermore, it is preferable to set the diameters of the upper and lower heating coils 21 and 22 to D, satisfying the following relationship. In addition, the aforementioned specified distance α is set to take into account the processing error of the open punching end 101, for example, it is set to about 0.5 mm.
[0091] 0≤a≤1.5×D
[0092] 0≤b≤1.5×D
[0093] α≤c≤1.2×D
[0094] 0≤d≤1.5×D
[0095] As described above, by placing the upper heating coil 21 within the upper suitable range X1 and the lower heating coil 22 within the lower suitable range X2, the end face 103 of the open punching end 101 is heated, and high heating efficiency can be maintained.
[0096] More preferably, taking into account the machining error of the open punching end 101, the upper heating coil 21 is positioned within a suitable upper range X1 at the closest point to the end face 103 of the open punching end 101. Similarly, more preferably, taking into account the machining error of the open punching end 101, the lower heating coil 22 is positioned within a suitable lower range X2 at the closest point to the end face 103 of the open punching end 101. This further improves heating efficiency.
[0097] Furthermore, preferably, when the steel plate 100, after being punched in the punching process, is placed on the heating fixture 200, such as... Figure 5 As shown, the upper heating coil 21 is offset outward from the steel plate 100. Thus, for example... Figure 9 As shown, when the open punched end 101 of the steel plate 100 is positioned relative to the heating coil 2 of the heating fixture 200 during the heating process, the steel plate 100 can be lowered directly to the ground, thus improving the settling ability of the steel plate 100.
[0098] Furthermore, in the above embodiment, the distance from the central axis of the heating coil 2 disposed on the side of the steel plate 100 that is stretched during the forming process to the end face 103 of the open punching end 101 may be closer than the distance from the central axis of the heating coil 2 disposed on the side of the steel plate 100 opposite to the stretched side to the end face 103 of the open punching end 101.
[0099] Therefore, by bringing the heating coil 2, which is located on the stretching side of the steel plate 100 during the forming process, closer to the end face 103 of the open punching end 101, the stretching portion of the steel plate 100 can be heated more significantly, thereby improving processability.
[0100] Furthermore, in the above embodiments, such as Figure 3 As shown, a heating coil 21 is arranged on the upper side and a heating coil 22 is arranged on the lower side. The heating coils 21 and 22 on the upper and lower sides form a loop, but are not limited to this.
[0101] For example, it could also be, such as Figure 10 As shown, two heating coils 23 are arranged on the upper side and two heating coils 24 are arranged on the lower side, forming a loop with the heating coils 23 and 24 on the upper and lower sides.
[0102] This increases the coil inductance and improves heating efficiency. Furthermore, the magnetic fields generated by the upper and lower heating coils 23 and 24 have a wider range of influence, thus improving the robustness of the relative positional relationship between the upper and lower heating coils 23 and 24 and the end face 103 of the open punching end 101, resulting in more stable heating.
[0103] also, Figure 10 The image above is a perspective view obtained by observing the heating coils arranged on the upper and lower sides of the open punching end 101 from an oblique angle. Figure 10 The image below is a three-dimensional view obtained by observing the heating coils from the top and bottom at an angle.
[0104] like Figure 10 As shown, two upper heating coils 23 and two lower heating coils 24 are arranged to be in a non-contact state along the end face 103 of the open punching end 101, and to sandwich the end face 103 of the open punching end 101. The two upper heating coils 23 are arranged on the open side, and the two lower heating coils 24 are arranged on the steel plate side. The current direction of the two upper heating coils 23 is opposite to the current direction of the two lower heating coils 24.
[0105] Therefore, by using the two upper heating coils 23 and the two lower heating coils 24, a current loop can be formed along the end face 103 of the open punching end 101, so that the current is concentrated on the end face 103. As a result, the current density at the end face 103 of the open punching end 101 can be increased, and the heating efficiency of the end face 103 can be improved.
[0106] Moreover, in the above embodiments, for example... Figure 4 As shown, the upper heating coil 21 is positioned on the open side, and the lower heating coil 22 is positioned on the steel plate side. The configuration of the upper heating coil 21 and the lower heating coil 22 being offset when viewed from above has been described, but it is not limited to this. For example, it could also be as follows... Figure 11 As shown, when viewed from above, the upper heating coil 21 and the lower heating coil 22 are not offset but overlap.
[0107] also, Figure 11 The above figure is obtained by looking at the heating coils 21 and 22 arranged on the upper and lower sides of the open punching end 101 from above. Figure 11 The image below is a three-dimensional view obtained by observing the heating coils 21 and 22 from an oblique angle, focusing on the upper and lower sides. Figure 11 As shown, the upper and lower heating coils 21 and 22 are configured to be in a non-contact state along the end face 103 of the open punching end 101 and to sandwich the end face 103 of the open punching end 101.
[0108] Therefore, a current loop can be formed along the end face 103 of the open punching end 101, so that the current is concentrated on the end face 103. As a result, the current density at the end face 103 of the open punching end 101 can be increased, and the heating efficiency of the end face 103 can be improved.
[0109] Next, the end face 103 of the open punching end 101 was heated by both the conventional heating coil and the heating coil 2 involved in this embodiment, and the heating results were compared. Figure 12 This diagram shows the heating results when heating is performed using a conventional heating coil and the heating coil involved in this embodiment. In this experiment, for the heating coil 2, the temperature distribution, magnetic field strength distribution, current density distribution, and vector of the open punching end 101 of the steel plate 100 were analyzed.
[0110] exist Figure 12 In the middle, on the left side, experimental results based on (a) the conventional configuration of a heating coil along the shape of the end face 103 of the open punch end 101 are shown; in the center, experimental results based on (b) the configuration in which the upper heating coil 21 and the lower heating coil 22 are not biased when viewed from above according to this embodiment are shown; and on the right side, experimental results based on (c) the configuration in which the upper heating coil 21 and the lower heating coil 22 are biased when viewed from above according to this embodiment are shown.
[0111] In addition, Figure 12 In the second paragraph, the temperature distribution is shown; below that, the magnetic field strength distribution is shown; and below that, the current density distribution and vector are shown.
[0112] like Figure 12 As shown in the temperature distribution, it can be confirmed that, compared with the conventional configuration in (a), the temperature of the end face 103 of the open punching end 101 in (b) and (c) of this embodiment increases significantly, and the heating efficiency is good.
[0113] Furthermore, it can be confirmed that, compared with the unbiased configuration of (b) this embodiment, the biased configuration of (c) this embodiment is subjected to a stronger magnetic field starting from the upper side corner 104 of the end face 103 of the open punching end 101, so the temperature rises significantly starting from the upper side corner 104.
[0114] When the end face 103 of the open punching end 101 is heated by the heating coils 21 and 22 on the upper and lower sides, the temperature peak is directly below the heating coils 21 and 22 on the upper and lower sides.
[0115] Therefore, (b) in the case of the non-biased configuration of this embodiment, it is necessary to precisely arrange the upper and lower heating coils 21, 22 relative to the end face 103 of the open punching end 101 so that the relative positional relationship between the upper and lower heating coils 21, 22 and the end face 103 of the open punching end 101 is accurately aligned.
[0116] On the other hand, (c) in the case of the biased configuration of this embodiment, the open punching end 101 is sandwiched obliquely upward by the upper heating coil 21 and the lower heating coil 22. As a result, the temperature peak is reached starting from the upper corner 104 of the end face 103 of the open punching end 101, so the management of the relative positional relationship between the upper and lower heating coils 21, 22 and the end face 103 of the open punching end 101 becomes insensitive.
[0117] Therefore, from such a robustness point of view, it is considered that (c) the biased configuration of this embodiment has advantages over (b) the unbiased configuration of this embodiment.
[0118] Moreover, such as Figure 12 As shown in the current density distribution and vector, (a) in the conventional configuration, the induced current flowing along the heating coil at the end face 103 of the open punching end 101 leaves the end face 103 and disperses inside the steel plate and flows in the opposite direction to form a loop, so the heating efficiency decreases.
[0119] On the other hand, it can be seen that in the configuration of this embodiment (b) and (c), the induced current flows in a concentrated manner on the end face 103 of the open punching end 101 directly below the heating coils 21 and 22, so the temperature peak is almost consistent with the end face 103 of the open punching end 101 that is to be heated, and the heating efficiency is high.
[0120] In particular, it is known that (c) in the configuration of this embodiment, an induced current flows from the upper side corner 104 of the open punching end 101 as the starting point. The current flows to the side opposite to the plate thickness, so a temperature peak is formed from the upper side corner 104 as the starting point, and the end face 103 of the open punching end 101 can be heated more concentratedly.
[0121] Next, regarding (b) the unbiased configuration of this embodiment and (c) the biased configuration of this embodiment, experiments were conducted to observe the changes in temperature distribution by moving the upper and lower heating coils 21 and 22 and heating them.
[0122] In this experiment, regarding the biasless configuration of this embodiment (b), the changes in temperature distribution were analyzed when the upper and lower heating coils were moved from the reference position to the outside of the steel plate and to the inside of the steel plate.
[0123] Similarly, regarding the biased configuration of this embodiment (c), the change in temperature distribution was analyzed when the upper and lower heating coils 21 and 22 were moved from the reference position to the outside of the steel plate 100 and to the bottom of the steel plate 100.
[0124] Figure 13 This is a graph showing the relationship between the upper and lower heating coils and the temperature distribution, which are the results of the above experiment. Furthermore, in Figure 13 In the diagram, (b) shows the change in temperature distribution of the unbiased configuration of this embodiment on the left, and (c) shows the change in temperature distribution of the biased configuration of this embodiment on the right.
[0125] like Figure 13 As shown, regarding the bias-free configuration of this embodiment (b), it can be seen that when the upper and lower heating coils 21 and 22 are moved from the reference position to the outside or inside of the steel plate 100, the relative positional relationship between the upper and lower heating coils 21 and 22 and the end face 103 of the open punching end 101 changes, and the position of the temperature peak also changes. Therefore, in order to concentrate the heating on the end face 103 of the open punching end 101, the management of the relative positional relationship between the upper and lower heating coils 21 and 22 and the end face 103 of the open punching end 101 becomes particularly important.
[0126] On the other hand, regarding the biased configuration of this embodiment (c), it is known that when the upper and lower heating coils 21 and 22 are moved from the reference position to the outside or bottom of the steel plate 100, the relative positional relationship between the upper and lower heating coils 21 and 22 and the end face 103 of the open punching end 101 changes, but the position of the temperature peak remains essentially unchanged. Therefore, even if the relative positional relationship between the upper and lower heating coils 21 and 22 and the end face 103 of the open punching end 101 changes slightly, the end face 103 of the open punching end 101 can be heated in a concentrated manner, thus enabling more stable heating.
[0127] Next, examples of molded articles based on the molding process method according to this embodiment will be described. Regarding molded articles formed using the molding process method according to this embodiment, for example... Figure 14 As shown, it is a molded article containing a flange forming part with a raised, curved flange and other stretched flange forming parts, and a molded article containing a forming part in which the line length of the end face 103 is significantly increased before and after processing.
[0128] In the above heating process, it is preferable that the heating coil 2 heats, for example, the curved flange forming portion of the high-strength material skeleton component of the vehicle after it has been formed in the forming process. This allows for the processing of forming portions where the end face length significantly increases before and after heating.
[0129] As a concrete shaped product, imagine as follows Figure 15 The image shows the FR lower arm used in the vehicle's suspension. Figure 15 In this embodiment, flange forming parts such as forks surrounded by dotted lines can also be formed using the forming process method described herein.
[0130] The forming process, for example, involves abutting the flange die or the like against the open punched end 101, where the excess portion has been punched out, to form a stretched flange. The flange forming portions at the lower part of the A-pillar and the lower outer part of the B-pillar are formed in this manner.
[0131] As the aforementioned molded product, it is envisioned that... Figure 16 The image shows the lower part of the A-pillar used in the window pillars of a vehicle. In Figure 16 In this embodiment, the forming parts such as corners surrounded by dotted lines can also be formed using the forming process method described herein.
[0132] As another molded product mentioned above, it is envisioned that... Figure 17 The lower outer part of the B-pillar of the vehicle shown. Figure 17 In this embodiment, the forming parts such as corners surrounded by dotted lines can also be formed using the forming process method described herein.
[0133] The forming process method described above includes: a blanking process, in which a portion of the end face 103 of the steel plate 100 is opened by blanking to form an open blanking end 101; and a heating process, in which a heating coil 2 is configured to be in a non-contact state along the end face 103 of the open blanking end 101 generated by the blanking process and to clamp the end face 103 of the open blanking end 101, and an induced electromotive force is generated in the steel plate 100 by allowing an alternating current to flow through the heating coil 2, thereby heating the end face 103 of the open blanking end 101. The current direction of the heating coil 21 disposed on one side of the end face 103 of the open blanking end 101 is opposite to the current direction of the heating coil 22 disposed on the other side of the end face 103 of the open blanking end 101.
[0134] Therefore, a current loop can be formed along the end face 103 of the open punching end 101, so that the current is concentrated on the end face 103. As a result, the current density at the end face 103 of the open punching end 101 can be increased, and the heating efficiency of the end face 103 can be improved.
[0135] Implementation Method 2
[0136] Figure 18 This is a diagram showing an example of a heating fixture. Figure 18The left-hand diagram shows the state of the sheet metal X before it is placed in the heating fixture 200, and the right-hand diagram shows the state of the sheet metal X after it is placed in the heating fixture 200. In this embodiment, the sheet metal X, after being punched by the above-described punching process, is placed in the heating fixture 200 for heating in the heating process.
[0137] like Figure 18 As shown, the heating fixture 200 includes: a heating coil 2 that heats the open punched end 101 of the sheet metal forming X; a positioning guide 3 that positions the sheet metal forming X in a predetermined position; and a base portion 4. An AC power supply 5 that supplies power to the heating coil 2 is connected to the heating coil 2.
[0138] The shape and configuration of the positioning guide 3 are set such that the position of the sheet metal X is naturally set simply by placing the sheet metal X on the positioning guide 3. The heating coil 2 and the positioning guide 3 are disposed on the base part 4 in a manner corresponding to the shape of the sheet metal X and the position of the heating part.
[0139] The position, number, and shape of the heating coil 2 are not limited to Figure 18 The example shown can be set arbitrarily. Similarly, the position, number, and shape of the positioning guide 3 are not limited to... Figure 18 The example shown can be set arbitrarily.
[0140] By using the heating fixture 200 of this embodiment, it is not necessary to heat the steel sheet X from the top and bottom while holding it as in the past. The steel sheet X can be easily placed in the heating fixture 200 for heating.
[0141] The heating process involved in this embodiment can also be as follows: Figure 19 As shown, this is performed during the idling process between the blanking and forming processes. The idling process is a process of adjusting the conveying distance when feeding the formed steel sheet X from the blanking process to the forming process; it is a standby process in which no processing is carried out.
[0142] Therefore, the idling process, which previously left the stamped sheet metal product X idle after the stamping process and before the forming process, can now be used to efficiently heat the sheet metal product X. Thus, no additional heating process is required, resulting in improved productivity.
[0143] Furthermore, according to this embodiment, by simply configuring the heating fixture 200 in the idling process of a conventional stamping press, the idling process can be transformed into a heating process without increasing the number of processes.
[0144] Figure 20 This is a schematic diagram illustrating an example of a process within a stamping press. Within the stamping press 500, for example, when utilizing... Figure 20The finger (holding part) 501 shown in the lower section continuously conveys the steel sheet formed product X while continuously performing [conveying] at a specified conveying interval. Figure 20 The upper section shows the forming process, blanking process, idle process, idle process, and blanking process. Therefore, by simply placing the heating fixture 200 in the position corresponding to the idle process, the idle process in the stamping press 500 can be easily replaced with a heating process.
[0145] Furthermore, as long as the heating fixture 200 can be configured, the heating process can be performed in any process of the stamping press 500 (e.g., forming process, blanking process, etc.).
[0146] Some embodiments of the present invention have been described, but these embodiments are merely illustrative and not intended to limit the scope of the invention. These novel embodiments can be implemented in a wide variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included within the scope and spirit of the invention, and are also included within the scope of the technical solutions described in the claims and their equivalents.
[0147] Based on the disclosure described herein, it will be apparent that embodiments of this disclosure can be varied in many ways. Such variations should not be considered as departing from the spirit and scope of this disclosure, and it will be apparent to those skilled in the art that all such modifications are intended to be included within the scope of the appended claims.
Claims
1. A forming process, comprising: The punching process involves punching a steel plate to form an open punched end, which is a portion of the end face of the steel plate. and In the heating process, the heating coil is configured to be in a non-contact state along the end face of the open punched end produced by the blanking process, and to clamp the end face of the open punched end. By allowing alternating current to flow through the heating coil, an induced electromotive force is generated in the steel plate, thereby heating the end face of the open punched end. The current direction of the heating coil disposed on one side of the end face of the open punching end is opposite to the current direction of the heating coil disposed on the other side of the end face of the open punching end. In the cross-sectional view of the open punching end and the heating coil, Viewed from above, the cross-section of the heating coil on one side of the end face of the open punching end does not overlap with the cross-section of the open punching end, while the cross-section of the heating coil on the other side of the end face of the open punching end overlaps with the cross-section of the open punching end.
2. The forming process method according to claim 1, wherein, In the heating process, The heating coil is located on one side of the end face of the open punching end. The heating coil is located on the other side of the end face of the open punching end, on the steel plate side.
3. The forming process method according to claim 2, wherein, In the heating process, The heating coil on one side is positioned on the upper side, and the heating coil on the other side is positioned on the lower side. In the cross-sectional view of the heating coils on the open punching end, upper side, and lower side, Viewed from above, the cross-section of the upper heating coil does not overlap with the cross-section of the open punching end, while the cross-section of the lower heating coil overlaps with the cross-section of the open punching end.
4. The forming process method according to claim 3, wherein, The upper heating coil is positioned within a suitable rectangular area on the upper side, defined by length a and width b. The lower heating coil is positioned within a suitable rectangular area on the lower side, defined by the length (c) and width (d). The suitable range on the upper side is set starting from the upper corner of the end face of the open punching end. The appropriate lower side range is set starting from a position α, which is a predetermined distance α from the lower side corner of the end face of the open punching end. Let the diameter of the upper and lower heating coils be D, satisfying the following relationship: 0≤a≤1.5×D 0≤b≤1.5×D α≤c≤1.2×D 0 ≤ d ≤ 1.5 × D.
5. The forming process method according to any one of claims 1 to 4, wherein, It also includes: a forming process, which shapes the stretch flange relative to the open punching end. The distance from the central axis of the heating coil disposed on the side of the steel plate that is stretched in the forming process to the end face of the open punching end is closer than the distance from the central axis of the heating coil disposed on the side opposite to the stretched side to the end face of the open punching end.
6. The forming process method according to any one of claims 1 to 4, wherein, In the heating process, the steel plate, after being punched in the punching process, is placed in the heating fixture and then heated by the heating coil. The heating fixture includes: a positioning guide for holding the steel plate after it has been punched in the punching process, used to position the steel plate in a specified position; and a heating coil for heating the open punched end face of the steel plate positioned by the positioning guide. When the steel plate after being punched through the punching process is placed on the positioning guide, the heating coil located on the front side is offset to the outside of the steel plate.
7. The forming process method according to any one of claims 1 to 4, wherein, It also includes: a forming process, which shapes the stretch flange relative to the open punching end. In the heating process, the heating coil heats the curved flange forming part of the high-strength material skeleton component of the vehicle after it has been formed by the forming process.
8. The forming process method according to claim 6, wherein, The heating process can be performed in any process of the stamping machine.
9. The forming process method according to claim 8, wherein, It also includes a forming process, which shapes the stretch flange relative to the punching end. The heating process is performed during the idling process of adjusting the conveying distance when the steel plate is conveyed from the punching process to the forming process.
10. The forming process method according to claim 9, wherein, Inside the stamping press, steel sheet formed products are continuously conveyed by the holding part, and at least the blanking process and the idle process are continuously performed at a predetermined conveying interval. By arranging the heating fixture at the position corresponding to the idling process, the idling process is replaced by the heating process.