Panel forming device and panel forming method

Abstract

To provide a panel forming technique capable of suppressing generation of a wrinkle in a panel end portion and eliminating necessity of finish blanking after panel formation.SOLUTION: A panel forming device 10 is a device for forming a panel end portion 2 of a panel 1 which is drawn and formed in advance. The panel forming device 10 includes a lower die 20 and an upper die 30, a cam pad 11, a gathering pad 12, and a gathering and bending blade 13. In a state where a panel base portion 6 is restricted by the lower die 20 and the cam pad 11 and a restricted part 5 of the panel end portion 2 is restricted by the lower die 20 and the gathering pad 12, by moving the upper die 30 with respect to the lower die 20, the panel end portion 2 is formed in a flange part by the gathering and bending blade 13. The gathering pad 12 presses the restricted part 5 against the lower die 20 such that, during the period up to the forming completion of the panel end portion 2, the restricted part 5 is pulled by a load received from the gathering and bending blade 13 and exists from a part between the lower die 20 and the gathering pad 12 to a part between the lower die 20 and the gathering and bending blade 13.SELECTED DRAWING: Figure 9

Description

Technical Field

[0001] The present invention relates to a panel forming apparatus and a panel forming method.

Background Art

[0002] Conventionally, when manufacturing an automobile body, a panel made of a steel plate or the like is formed into a predetermined shape by press forming using a forming die. In Patent Document 1 below, as this type of press forming method, while one end side portion on the outer side of the panel is pressed against the lower die by a cam pad, and the other end side portion on the inner side of the panel is pressed against the lower die by a panel holding pad, the panel is compressed between a cam section die, which is a bending blade, and the lower die to form a flange portion. In this press forming method, from the start to the completion of forming, the one end side portion and the other end side portion of the panel are in a constrained state with being clamped. According to this press forming method, by continuously applying tension until the completion of forming of the panel, it is intended to suppress the occurrence of wrinkles on the panel surface.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the case of the press forming method of Patent Document 1, while an effect of suppressing wrinkle generation is expected, since the constrained state of one end side portion on the outer side of the panel continues until the completion of forming, a non-formed portion that is not formed by the bending blade remains in this one end side portion. When the non-formed portion is a site unnecessary for the final product, a process of finally cutting and removing this non-formed portion, a process called so-called "finishing blanking process", becomes necessary. As a result, a problem may occur in that the number of working steps related to panel forming increases.

[0005] The present invention has been made in view of such problems, and aims to provide a panel forming technique that suppresses the generation of wrinkles at the panel end and eliminates the need for finish punching after panel forming.

Means for Solving the Problems

[0006] One aspect of the present invention is a panel forming device for forming a panel end of a panel pre-formed by drawing, comprising a lower die and an upper die, a cam pad for pressing a panel base inside the panel in the depth direction rather than the panel end of the panel against the lower die, a pushing pad for pressing a constrained portion outside the panel in the depth direction of the panel end against the lower die, a pushing bending blade provided to move in conjunction with the upper die, for compressing the panel end between the panel end and the lower die to form a recessed flange portion, and by moving the upper die relative to the lower die with the panel base constrained by the lower die and the cam pad and the constrained portion of the panel end constrained by the lower die and the pushing pad, the panel end is formed into the flange portion by the pushing bending blade, wherein the pushing pad presses the constrained portion against the lower die so that the constrained portion is pulled by the load received by the constrained portion from the pushing bending blade until the forming of the panel end is completed and escapes from between the lower die and the pushing pad to between the lower die and the pushing bending blade, a panel forming device, is provided.

[0007] Also, another aspect of the present invention is a panel forming method for forming a panel end of a panel pre-formed by drawing, comprising a constraining step of constraining a panel base inside the panel in the depth direction rather than the panel end of the panel with a lower die and a cam pad, and constraining a constrained portion outside the panel in the depth direction of the panel end with the lower die and a pushing pad, A forming step of moving the upper mold relative to the lower mold while restraining the panel base portion and the restrained portion, thereby compressing the panel end portion between the lower mold and the approaching bending blade to form a recessed flange portion. having In the restraining step, the approaching pad presses the restrained portion against the lower mold so that the restrained portion is pulled by the load received by the approaching bending blade from the approaching bending blade during the forming of the panel end portion until the forming of the panel end portion is completed, and escapes from between the lower mold and the approaching pad to between the lower mold and the approaching bending blade. A panel forming method. is in.

Advantages of the Invention

[0008] In each of the above aspects, until the panel end portion of the panel is completely formed by the approaching bending blade, the restrained portion of the panel end portion is pulled by the load received by the approaching bending blade and escapes from between the lower mold and the approaching pad to between the lower mold and the approaching bending blade. In this way, the restrained portion is pressed against the lower mold by the approaching pad. As a result, until the restrained portion of the panel end portion escapes between the lower mold and the approaching bending blade, tension can be applied to the restrained portion by the sandwiching effect of the lower mold and the approaching pad. By continuously applying tension to the restrained portion until immediately before the completion of the forming of the panel end portion, it is possible to suppress the occurrence of wrinkles in the flange portion after the panel is formed without restraining the restrained portion until the completion of the forming. In addition, since the forming by the approaching bending blade is completed in a state where the restrained portion of the panel end portion has escaped between the lower mold and the approaching bending blade, it is possible to prevent a non-formed portion that is not formed by the approaching bending blade from remaining at the panel end portion. For this reason, a finishing punching process for finally cutting and removing the non-formed portion is not required.

[0009] As described above, according to the above aspect, it is possible to provide a panel forming technique that suppresses the occurrence of wrinkles at the panel end portion and eliminates the need for finishing punching after panel forming.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

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Figure 8

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Figure 10

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Figure 16

MODE FOR CARRYING OUT THE INVENTION

[0011] Preferred embodiments of the above-described aspects will be described below.

[0012] In the panel forming apparatus according to the above aspect, it is preferable to preliminarily deform the constrained portion at the panel end by pressing the constrained portion against the lower die over the entire width direction by the pushing pad so as to reduce the difference in the width direction of the remaining machining amount by the pushing bending blade. Further, in the panel forming method according to the above aspect, in the restraining step, it is preferable to preliminarily deform the constrained portion at the panel end by pressing the constrained portion against the lower die over the entire width direction by the pushing pad so as to reduce the difference in the width direction of the remaining machining amount by the pushing bending blade in the forming step. In this way, even when the machining amount in the thickness direction is different in the width direction when the panel end is formed into the flange portion, it is possible to suppress the occurrence of wrinkles in the flange portion after panel forming by reducing the difference in the width direction of the remaining machining amount by the pushing bending blade.

[0013] In the panel forming apparatus according to the above aspect, based on the thickness of the constrained portion and the restraining force applied to the constrained portion pressed against the lower die by the pushing pad, it is preferable that the gap dimension between the lower die and the pushing pad at the time of restraining the constrained portion is preset so as to escape from the constrained portion between the lower die and the pushing pad. Further, the panel forming method according to the above aspect preferably has a gap setting step of presetting the gap dimension between the lower die and the pushing pad at the time of restraining the constrained portion based on the thickness of the constrained portion and the restraining force applied to the constrained portion pressed against the lower die by the pushing pad so as to escape from the constrained portion between the lower die and the pushing pad. In this way, by using a simple operation of presetting the gap dimension between the lower die and the pushing pad at the time of restraining the constrained portion to be constant, it is possible to cause the constrained portion to escape from between the lower die and the pushing pad to between the lower die and the pushing bending blade before the forming of the panel end is completed.

[0014] The panel forming apparatus according to the above aspect preferably includes a gap setting mechanism portion capable of setting the gap dimension. By setting the gap dimension using the gap setting mechanism portion, it is possible to obtain appropriate conditions for suppressing the occurrence of wrinkles in the flange portion after panel forming.

[0015] In the panel forming device of the above aspect, the gap setting mechanism unit has a first block provided on the lower mold and a second block provided on the pushing pad so as to be capable of contacting the first block. It is preferable that the gap dimension in the state where the first block and the second block are in contact with each other is variable by changing the height of at least one of the first block and the second block. Thereby, by using the first block provided on the lower mold and the second block provided on the pushing pad, the structure of the gap setting mechanism unit can be simplified.

[0016] The panel forming device of the above aspect includes a pad holding mechanism unit interposed between the pushing pad and the pushing bending blade. The pushing pad is elastically held so as to be retractable from the initial position protruding from the pushing bending blade toward the lower mold by the pad holding mechanism unit, and is configured to retreat from the initial position to the retreat position by the reaction force received from the lower mold during forming by the pushing bending blade. According to this panel forming device, the pushing pad is incorporated into the pushing bending blade via the pad holding mechanism unit, and by continuing the operation of moving the upper mold toward the lower mold, the operation of pressing and restraining the constrained portion of the panel end against the lower mold by the pushing pad and the operation of forming the panel end with the pushing bending blade can be executed as a series of continuous operations. Thereby, the forming time required for panel forming can be shortened.

[0017] In the panel forming device of the above aspect, it is preferable that the pad holding mechanism unit has a rod attached to the pushing pad, a piston connected to the rod, and a cylinder that houses the piston and the working fluid and elastically biases the rod by using the reaction force when the working fluid is compressed by the piston. According to this panel forming device, in order to elastically hold the pushing pad so as to be retractable in the initial position, by adopting a structure in which the rod is elastically biased by using the reaction force when the working fluid is compressed by the piston, the structure of the pad holding mechanism unit can be simplified.

[0018] The panel forming method according to the above aspect preferably includes a gap adjustment step of adjusting the gap dimension according to the wrinkle generation situation in the flange portion. By performing the gap adjustment step to adjust the gap dimension, it becomes possible to appropriately set the appropriate conditions for suppressing the generation of wrinkles in the flange portion after panel forming.

[0019] Hereinafter, specific embodiments of the panel forming apparatus and the panel forming method according to the above aspect will be described with reference to the drawings.

[0020] In this specification and the drawings, unless otherwise specified, the width direction of the panel and the panel forming apparatus is indicated by arrow X, the depth direction is indicated by arrow Y, and the thickness direction is indicated by arrow Z. Also, the width direction X corresponds to the vehicle width direction, the depth direction Y corresponds to the vehicle length direction, and the thickness direction Z corresponds to the vehicle height direction.

[0021] (Embodiment 1) FIG. 1 shows a panel 1 after "drawing forming" which is a primary forming, and a panel 1A after "bending processing" which is a secondary forming with respect to the panel 1. Both the drawing forming and the bending processing are one of the press forming processes. In this embodiment, as the panels 1 and 1A, the roof panel of a hatchback type automobile body is exemplified. The panels 1 and 1A are made of a steel plate.

[0022] In the automobile body, the cross-sectional shape of the flange portion of panel 1A is not uniform in the width direction X, and the cross-sectional shape varies according to the position in the width direction X. For example, in the flange portion on the rear end side of panel 1A of a hatchback-type automobile, the depth of the recess is greater on both end sides than in the central portion in the width direction X. Therefore, when a bending blade is pressed against panel end portion 2 on the rear side of panel 1 that has been pre-drawn over the entire length in the width direction X to form the flange portion, the processing amount and the compression deformation direction of panel 1A differ for each part, which may cause a problem that wrinkles remain on the surface of the flange portion of panel 1A as the final product. Such problems can occur not only in the manufacture of the roof panel of an automobile body, but also in the manufacture of panels other than the roof panel and in the manufacture of panels in other fields.

[0023] 1. Structure of Panel 1 As shown in FIG. 1, panel end portion 2 on the rear side of panel 1 after drawing includes panel end portion 2a near the center in the width direction X and panel end portions 2b on both end sides in the width direction X. As shown in FIGS. 1 and 2, both panel end portion 2a and panel end portion 2b are provided with a first drawing portion 3 and a second drawing portion 4.

[0024] The first drawing portion 3 is a portion formed to extend in the width direction X on the outer side in the depth direction Y. In this embodiment, the width direction X substantially corresponds to the vehicle width direction. The first drawing portion 3 includes a constrained portion 5 that is constrained by a lower die 20 and a pressing pad 12 described later (see FIG. 2).

[0025] The second drawing portion 4 is a portion formed to extend along the first drawing portion 3 on the inner side in the depth direction Y than the first drawing portion 3. Panel 1 includes a panel base portion 6 on the inner side in the depth direction Y than panel end portion 2 (see FIG. 2).

[0026] 2. Structure of Panel 1A As shown in FIGS. 3 and 4, a flange portion 7 is provided on the panel 1A after the bending process. The flange portion 7 is constituted by a first drawing portion 3 that is bent so as to be recessed downward at each of the panel end portions 2a and 2b, and a second drawing portion 4 that is bent so as to be recessed inward.

[0027] The flange portion 7 of the panel 1A has different cross-sectional shapes at the panel end portion 2a and the panel end portion 2b. Specifically, the panel end portion 2a and the panel end portion 2b are the same in that the cross-sectional shape of the first drawing portion 3 is substantially V-shaped, and are different in that the recess depth of the first drawing portion 3 is larger at the panel end portion 2b than at the panel end portion 2a. Also, the second drawing portion 4 of the panel end portion 2a is recessed inward. The recessed shape of this second drawing portion 4 is a shape in which a part of the recess is hidden when the panel end portion 2a is viewed from above, and is also referred to as a "shape with a depression angle of declination".

[0028] 3. Structure of Panel Forming Apparatus 10 The panel forming apparatus 10 of Embodiment 1 is an apparatus for forming the panel end portion 2 of the panel 1 that has been drawn and formed in advance. As shown in FIGS. 5 and 6, this panel forming apparatus 10 includes, as its main components, a lower die 20, an upper die 30, a cam pad 11, a pushing pad 12, a bending blade 13, a gap setting mechanism portion 40, and a pad holding mechanism portion 50.

[0029] On the lower die 20, a first forming surface 20a (see FIG. 5) is formed at the central portion in the width direction X, and second forming surfaces 20b (see FIG. 6) are formed on both end sides in the width direction X. The first forming surface 20a is a forming surface for forming the panel end portion 2a of the panel 1 into the flange portion 7 of the panel 1A. In contrast, the second forming surface 20b is a forming surface for forming the panel end portion 2b of the panel 1 into the flange portion 7 of the panel 1A.

[0030] As shown in Fig. 5, the first forming surface 20a is provided on the lower die 20 so as to face the first blade surface 13a provided at the central portion in the width direction X of the bending blade 13. This first forming surface 20a has a shape following the first blade surface 13a of the bending blade 13. The panel end portion 2a of the panel 1 is formed into the flange portion 7 of the panel 1A by the first forming surface 20a of the lower die 20 and the first blade surface 13a of the bending blade 13.

[0031] As shown in Fig. 6, the second forming surface 20b is provided on the lower die 20 so as to face the second blade surfaces 13b provided on both end sides in the width direction X of the bending blade 13. This second forming surface 20b has a shape following the second blade surfaces 13b of the bending blade 13. The panel end portion 2b of the panel 1 is formed into the flange portion 7 of the panel 1A by the second forming surface 20b of the lower die 20 and the second blade surfaces 13b of the bending blade 13.

[0032] The upper die 30 is configured to move up and down with respect to the lower die 20 by a drive mechanism portion (not shown). The upper die 30 is configured to approach the lower die 20 as it moves downward, and to move away from the lower die 20 as it moves upward.

[0033] 3-1. Structure of the cam pad 11 As shown in Figs. 5 and 6, the cam pad 11 is a pad for pressing the panel base portion 6 (see Fig. 2) of the panel 1 against the lower die 20. The cam pad 11 extends in the width direction X. The cam pad 11 is a member separate from the bending blade 13 and is disposed above the lower die 20.

[0034] 3-2. Structure of the bending pad 12 As shown in FIGS. 5 and 6, the pushing pad 12 is a pad for pressing the constrained portion 5 on the outer side (free end side) in the depth direction Y of the panel end portions 2a and 2b of the panel 1 against the lower mold 20. The pushing pad 12 is a member integrally incorporated into the pushing bending blade 13 and extends in the width direction X. The pushing pad 12 is configured to move in conjunction with the upper mold 30. A pad holding mechanism portion 50 is interposed between the pushing pad 12 and the pushing bending blade 13. That is, the pushing pad 12 is incorporated into the pushing bending blade 13 via the pad holding mechanism portion 50. The pushing pad 12 is elastically held so as to be retractable from the pushing bending blade 13 toward the lower mold 20 at an initial position Q1 protruding from the pushing bending blade 13 by the pad holding mechanism portion 50. The pushing pad 12 is configured to retract from the initial position Q1 to a retracted position Q2 (see FIGS. 13 and 14) described later by the reaction force received from the lower mold 20 during forming by the pushing bending blade 13.

[0035] 3-3. Structure of the Pushing Bending Blade 13 The pushing bending blade 13 is a processing blade for compressing the panel end portions 2a and 2b of the panel 1 between the lower mold 20 to form a recessed flange portion 7. The pushing bending blade 13 extends in a long shape in the width direction X and is configured to move in conjunction with the upper mold 30. The first blade surface 13a on the tip side of the pushing bending blade 13 has a shape following the first forming surface 20a of the lower mold 20, and the second blade surfaces 13b on both sides in the width direction X of the first blade surface 13a have shapes following the second forming surfaces 20b of the lower mold 20. The pushing bending blade 13 has a slide member 14 interposed between it and the upper mold 30 and a slide member 15 interposed between it and the lower mold 20. The pushing bending blade 13 is configured to move in the forming direction A by moving the upper mold 30 downward in FIG. 5 with respect to the lower mold 20 so that the slide member 14 slides with the upper mold 30 and the slide member 15 slides with the lower mold 20.

[0036] 3-4. Structure of the Pad Holding Mechanism Portion 50 As shown in FIG. 5, the pad holding mechanism portion 50 is provided in the concave portion 13c of the bending blade 13. The pad holding mechanism portion 50 is for holding the pushing pad 12 and includes a rod 51, a piston 52, and a cylinder 53. The tip of the rod 51 is attached to the rear end surface of the pushing pad 12. The piston 52 is connected to the rod 51. The cylinder 53 houses the piston 52 and the working fluid, and is configured to elastically bias the rod 51 by utilizing the reaction force when the working fluid is compressed by the piston 52. According to such a configuration, the elastic biasing force acting on the pushing pad 12 via the rod 51 is minimized at the initial position Q1 and maximized at the retracted position Q2. In this embodiment, the pushing pad 12 extends in the width direction X. In order to stably elastically hold the pushing pad 12, it is preferable to provide a plurality of pad holding mechanism portions 50 juxtaposed in the width direction X.

[0037] Note that the working fluid in the cylinder 53 may be a gas or a liquid, and its type is not particularly limited. However, typically, a gas such as nitrogen that is easy to handle can be used as the working fluid. The pad holding mechanism portion 50 having such a configuration is generally also referred to as a "gas spring". On the other hand, the structure for elastically biasing the pushing pad 12 is not limited to those using a working fluid. If necessary, an elastic member such as a spring member can be used instead of or in addition to the working fluid.

[0038] 3-5. Structure of the gap setting mechanism portion 40 As shown in FIG. 7, the gap setting mechanism portion 40 is configured to be able to set the gap dimension t between the lower mold 20 and the approaching pad 12 when the constrained portion 5 of the panel end portions 2a, 2b is constrained. The gap setting mechanism portion 40 includes a first block 41 provided on the lower mold 20 and a second block 42 provided on the approaching pad 12 so as to be able to abut against the first block 41. The first block 41 and the second block 42 are also referred to as "distance blocks". According to this gap setting mechanism portion 40, the gap dimension t in the state where the first block 41 and the second block 42 are in contact with each other is made variable by changing the block height of at least one of the first block 41 and the second block 42. By using this gap setting mechanism portion 40, based on the thickness d of the constrained portion 5 and the constraining force F applied to the constrained portion 5 pressed against the lower mold 20 by the approaching pad 12, the gap dimension t is preset so that the constrained portion 5 can escape from between the lower mold 20 and the approaching pad 12. Further, according to this gap setting mechanism portion 40, the gap dimension t can be appropriately adjusted as needed.

[0039] The "constraining force F" referred to here is a force that constrains the constrained portion 5 so as to prevent the constrained portion 5 from escaping from between the lower mold 20 and the approaching pad 12 during the molding of the panel end portions 2a, 2b. That is, the constraining force F is a tension (pulling force) that restricts the movement of the constrained portion 5 when the constrained portion 5 attempts to move in the right direction in FIG. 7. The constraining force F decreases as the gap dimension t increases and increases as the gap dimension t decreases. Therefore, the setting function and adjustment function of the gap dimension t by the gap setting mechanism portion 40 can also be referred to as the setting function and adjustment function of the constraining force F.

[0040] 4. Panel Molding Method Next, with reference to FIGS. 8 to 16, a panel molding method for molding the panel end portion 2 of the panel 1 pre-drawn will be described in detail.

[0041] As shown in FIG. 8, the panel forming method of Embodiment 1 is achieved by sequentially executing the processes from the first step S101 to the eighth step S108. Note that, if necessary, another step may be added, at least one of a plurality of steps may be divided into a plurality, or a plurality of steps may be integrated into one.

[0042] 4-1. Gap Setting Step The first step S101 in FIG. 8 is a step of presetting the gap dimension t between the lower die 20 and the alignment pad 12. This first step S101 corresponds to the gap setting step. The first step S101 is executed by an operator using the gap setting mechanism unit 40. In the first step S101, the block height of at least one of the first block 41 and the second block 42 of the gap setting mechanism unit 40 is set so that a desired gap dimension t is formed based on the thickness d and the restraint force F of the constrained portion 5.

[0043] 4-2. Restraint Step The second step S102 in FIG. 8 is a step of setting the panel 1 after drawing forming, which has been drawn and formed in advance, on the lower die 20. Although not particularly shown, the drawing forming is performed using a drawing die having a known structure. According to the second step S102, the panel 1 is set on the lower die 20.

[0044] The third step S103 in FIG. 8 is a step of restraining the panel base portion 6 of the panel 1 between the lower die 20 and the cam pad 11 following the second step S102. In the third step S103, the cam pad 11 is lowered so that the cam pad 11 approaches the lower die 20. Thereby, the panel base portion 6 is pressed against the lower die 20 by the cam pad 11. According to the third step S103, as shown in FIGS. 9 and 10, the panel base portion 6 of the panel 1 is sandwiched and restrained from above and below by the lower die 20 and the cam pad 11.

[0045] The fourth step S104 in FIG. 8 is a step of restraining the restrained portion 5 of the panel 1 with the lower mold 20 and the approaching pad 12 following the third step S103. In the fourth step S104, the upper mold 30 is lowered until the approaching pad 12 approaches the lower mold 20 and the first block 41 and the second block 42 of the gap setting mechanism portion 40 come into contact. Thereby, the approaching pad 12 is pressed against the restrained portion 5 over the entire length in the width direction X, and the restrained portion 5 is pressed against the lower mold 20 by this approaching pad 12. According to the fourth step S104, as shown in FIGS. 11 and 12, the approaching bending blade 13 descends from the first position P1 to the second position P2 with respect to the lower mold 20, and the restrained portion 5 of the panel 1 is clamped and restrained from above and below by the lower mold 20 and the approaching pad 12.

[0046] As described above, the steps from the second step S102 to the fourth step S104 correspond to a restraining step of restraining both the panel base portion 6 and the restrained portion 5 of the panel 1.

[0047] 4-3. Forming Process The fifth step S105 in FIG. 8 is a step of compressing the panel end portions 2a, 2b of the panel 1 between the lower mold 20 and the approaching bending blade 13 and forming them into the flange portion 7 having a concave shape with the approaching bending blade 13. This fifth step S105 corresponds to the forming process. In the fifth step S105, as shown in FIGS. 13 and 14, with the panel base portion 6 and the restrained portion 5 restrained, the upper mold 30 is lowered with respect to the lower mold 20 so that the approaching bending blade 13 moves from the second position P2 to the third position P3, which is the bottom dead center, in the forming direction A. At this time, the rod 51 of the pad holding mechanism portion 50 retreats so that the protruding length from the cylinder 53 becomes shorter while increasing the elastic biasing force applied to the approaching pad 12 as the approaching pad 12 receives a reaction force from the restrained portion 5 and the lower mold 20. Then, the lowering operation of the upper mold 30 is continued until the first blade surface 13a of the approaching bending blade 13 fits into the first forming surface 20a of the lower mold 20 through the panel end portion 2a, and the second blade surface 13b of the approaching bending blade 13 fits into the second forming surface 20b of the lower mold 20 through the panel end portion 2a. The approaching pad 12 retreats from the initial position Q1 to the retreat position Q2 with respect to the approaching bending blade 13.

[0048] In the fifth step S105, the constrained portion 5 is constrained so as to be pulled by the load received from the approaching bending blade 13 until the molding of the panel ends 2a and 2b is completed, and to escape from between the lower mold 20 and the approaching pad 12 to between the lower mold 20 and the approaching bending blade 13. That is, in the fourth step S104, the approaching pad 12 presses the constrained portion 5 against the lower mold 20 in advance so that the constrained portion 5 escapes from between the lower mold 20 and the approaching pad 12 in the fifth step S105. That is, in this embodiment, how to constrain the constrained portion 5 in the fourth step S104, that is, the setting of the gap dimension t in the first step S101 is extremely important. In the fifth step S105, the constrained portion 5 of the panel ends 2a and 2b slides between the lower mold 20 and the approaching pad 12 while receiving a tensile force against the constraining force F (see FIG. 7) received from the lower mold 20 and the approaching pad 12, and moves to between the lower mold 20 and the approaching bending blade 13. As a result, the panel ends 2a and 2b are compression molded into a flange portion 7 having a predetermined shape according to the shapes of the approaching bending blade 13 and the lower mold 20. At this time, since the constrained portion 5 continues to receive a tensile force until immediately before the molding is completed, it is possible to suppress the occurrence of wrinkles in the flange portion 7 after the panel molding even if the constrained portion 5 is not continuously constrained until after the molding is completed. Moreover, since there is no portion finally constrained between the lower mold 20 and the approaching pad 12, post-molding finishing punching is unnecessary.

[0049] 4-4. Processing amount Here, the processing amount when forming the panel end portions 2a and 2b of the panel 1 into the flange portion 7 (see FIGS. 3 and 4) by the bending blade 13 will be described. In the panel 1 of this embodiment, since the cross-sectional shapes of the panel end portion 2a and the panel end portion 2b are different, when forming the flange portion 7 directly with the bending blade 13 without performing the fourth step S104, the conventional processing amounts in the thickness direction Z are different in the width direction X. Specifically, when comparing the processing amount D1 (see FIG. 9) of the panel end portion 2a and the processing amount D2 (see FIG. 10) of the panel end portion 2b, the processing amount D2 exceeds the processing amount D1. And when the difference between the processing amount D2 and the processing amount D1 is large, it can be a factor causing wrinkles on the surface of the flange portion 7 after panel forming. The processing amounts D1 and D2 are defined as the movement amounts along the forming direction A from when the bending blade 13 contacts the panel end portions 2a and 2b until the forming is completed.

[0050] Therefore, in this embodiment, in the fourth step S104, the constrained portion 5 of the panel 1 is pressed against the lower die 20 over the entire width direction X by the pressing pad 12 and deformed in advance, so as to reduce the difference in the remaining processing amounts in the width direction X by the bending blade in the subsequent fifth step S105. That is, when comparing the remaining processing amount E1 (see FIG. 11) of the constrained portion 5 at the panel end portion 2a and the remaining processing amount E2 (see FIG. 12) of the constrained portion 5 at the panel end portion 2b, the fourth step S104 is performed so that the difference between the remaining processing amount E2 and the remaining processing amount E1 is non-existent or slight.

[0051] According to the fifth step S105, when the remaining processing amounts E1 and E2 become approximately the same, the constraint of the constrained portion 5 is released. The remaining processing amounts E1 and E2 are the substantial processing amounts by the bending blade 13, and the remaining processing amounts (substantial processing amounts) of the constrained portion 5 can be equalized in the width direction X. As a result, even when forming the panel 1 with different cross-sectional shapes at the panel end portion 2a and the panel end portion 2b using the bending blade 13, by performing the fourth step S104 before the implementation of the fifth step S105, it is possible to suppress the occurrence of wrinkles on the surface of the flange portion 7 after panel forming. In particular, the smaller the difference between the remaining processing amount E1 and the remaining processing amount E2, the higher the effect of suppressing wrinkle generation.

[0052] The sixth step S106 in FIG. 8 is a step of releasing the formed panel 1A. Although not particularly shown, in this sixth step S106, by moving the upper die 30 upward, the bending blade 13 is moved in the direction opposite to the forming direction A together with the pressing pad 12. Also, the pressing of the panel base 6 by the cam pad 11 is released. According to the sixth step S106, as shown in FIGS. 15 and 16, the contact between the bending blade 13 and the pressing pad 12 with respect to the panel 1A is released, and by releasing the pressing by the cam pad 11, the formed panel 1A is released. At this time, the pressing pad 12 returns from the retracted position Q2 to the initial position Q1 with respect to the bending blade 13 by the pad holding mechanism portion 50. And finally, the panel 1A is taken out from the lower die 20.

[0053] The seventh step S107 in FIG. 8 is a step in which an operator determines whether it is necessary to adjust the gap dimension t according to the wrinkle generation situation in the flange portion 7 of the panel 1A. If it is determined in the seventh step S107 that the adjustment of the gap dimension t is not necessary, the process ends, and thereafter, the forming of another panel 1 is repeated with the set gap dimension t remaining. On the other hand, if it is determined in the seventh step S107 that the adjustment of the gap dimension t is necessary, the process proceeds to the eighth step S108, and then returns to the second step S102. And if necessary, the processes from the second step S102 to the eighth step S108 are repeated.

[0054] 4-5. Gap Adjustment Step The eighth step S108 in FIG. 8 is a step of adjusting (re-setting) the gap dimension t already set in the first step S101 according to the wrinkling situation in the flange portion 7 of the panel 1A. This eighth step S108 corresponds to the gap adjustment process. In the eighth step S108, a change in the height of at least one of the first block 41 and the second block 42 of the gap setting mechanism portion 40 (for example, the operation of replacing a block with a predetermined height with a block of a different height) is executed by the operator. Thereby, the gap dimension t is adjusted so that a desired restraining force F is applied to the restrained portion 5 to suppress the occurrence of wrinkles in the flange portion 7.

[0055] Note that in the above-described panel forming method, the seventh step S107 and the eighth step S108 may be omitted as necessary.

[0056] 5. Operational Effects According to the above-described Embodiment 1, the following operational effects can be obtained.

[0057] In Embodiment 1, until the panel ends 2a and 2b of the panel 1 are completely formed by the bending blade 13, the restrained portion 5 of the panel ends 2a and 2b is pulled by the load received from the bending blade 13 and escapes from between the lower die 20 and the padding pad 12 to between the lower die 20 and the bending blade 13. In this way, the restrained portion 5 is pressed against the lower die 20 by the padding pad 12. Thereby, until the restrained portion 5 of the panel ends 2a and 2b escapes between the lower die 20 and the bending blade 13, a tension can be applied to the restrained portion 5 by the clamping effect of the lower die 20 and the padding pad 12. By continuously applying tension to the restrained portion 5 until immediately before the completion of the forming of the panel ends 2a and 2b, it becomes possible to suppress the occurrence of wrinkles in the flange portion 7 after the panel forming even without restraining the restrained portion 5 until the completion of the forming. Further, since the forming by the bending blade 13 is completed in a state where the restrained portion 5 of the panel ends 2a and 2b has escaped between the lower die 20 and the bending blade 13, it is possible to prevent a non-formed portion that is not formed by the bending blade 13 from remaining at the panel ends 2a and 2b. For this reason, a finishing punching process for finally cutting and removing the non-formed portion is not required.

[0058] Therefore, according to Embodiment 1, it is possible to suppress the occurrence of wrinkles at the panel end portion 2 and eliminate the need for finish punching after panel forming.

[0059] According to Embodiment 1, by reducing the difference in the width direction X of the remaining machining amounts E1 and E2 by the approaching bending blade 13, even when the machining amounts D1 and D2 in the thickness direction Z differ in the width direction X when the panel end portion 2 is formed into the flange portion 7, it is possible to suppress the occurrence of wrinkles in the flange portion 7 after panel forming.

[0060] According to Embodiment 1, by using a simple operation of presetting the gap dimension t between the lower die 20 and the approaching pad 12 during the restraint of the restrained portion 5, the restrained portion 5 can be made to escape from between the lower die 20 and the approaching pad 12 to between the lower die 20 and the approaching bending blade 13 until the forming of the panel end portions 2a and 2b is completed.

[0061] According to Embodiment 1, by adjusting the gap dimension t using the gap setting mechanism portion 40, it is possible to obtain appropriate conditions for suppressing the occurrence of wrinkles in the flange portion 7 after panel forming.

[0062] According to Embodiment 1, the structure of the gap setting mechanism portion 40 can be simplified by using the first block 41 provided on the lower die 20 and the second block 42 provided on the approaching pad 12.

[0063] According to Embodiment 1, the approaching pad 12 is incorporated into the approaching bending blade 13 via the pad holding mechanism portion 50, and by continuing the operation of moving the upper die 30 toward the lower die 20, the operation of pressing and restraining the restrained portion 5 of the panel end portions 2a and 2b against the lower die 20 by the approaching pad 12 and the operation of forming the panel end portions 2a and 2b with the approaching bending blade 13 can be executed as a series of continuous operations. Thereby, the forming time required for panel forming can be shortened.

[0064] According to Embodiment 1, in order to elastically hold the draw pad 12 so as to be retractable at the initial position Q1, by adopting a structure in which the rod 51 is elastically biased by utilizing the reaction force during compression of the working fluid by the piston 52, the structure of the pad holding mechanism portion 50 can be simplified.

[0065] The present invention is not limited to only the above-described typical forms, and various applications and modifications can be considered without departing from the object of the present invention. For example, the following respective forms applying the above-described form can also be implemented.

[0066] In the above-described form, the case where the gap dimension t between the lower die 20 and the draw pad 12 is set in advance and panel forming is performed with this gap dimension t was exemplified. However, instead of this, the gap dimension t may be variably controlled according to the restraining force F received by the restrained portions 5 of the panel end portions 2a, 2b during panel forming.

[0067] In the above-described form, the case where the gap dimension t is set using the gap setting mechanism portion 40 was exemplified. However, instead of this, the gap dimension t may be set based on the relative position control of the draw pad 12 with respect to the lower die 20. In this case, it becomes possible to omit the gap setting mechanism portion 40.

[0068] In the above-described form, the structure in which the draw pad 12 is incorporated into the draw bending blade 13 via the pad holding mechanism portion 50 was exemplified. However, instead of this, a structure may be adopted in which the draw pad 12 and the draw bending blade 13 are separate bodies and move independently of each other.

[0069] In the above-described form, the case of forming the rear end portion of the roof panel of a hatchback type automobile body was exemplified. However, this form can also be applied to the forming of panels other than the roof panel of an automobile body and the forming of panels of products other than an automobile body.

Explanation of Reference Numerals

[0070] 1… Panel, 2, 2a, 2b… Panel ends, 5… Constrained part, 6… Panel base, 7… Flange part, 10… Panel forming device, 11… Cam pad, 12… Pushing pad, 13… Pushing bending blade, 20… Lower mold, 30… Upper mold, 40… Gap setting mechanism part, 41… First block, 42… Second block, 50… Pad holding mechanism part, 51… Rod, 52… Piston, 53… Cylinder, d… Thickness, t… Gap dimension, E1, E2… Remaining machining amount, F… Constraining force, Q1… Initial position, Q2… Retracted position, S101~S108… Panel forming method, S101… First step (Gap setting process), S102~S104… Second step to fourth step (Constraining process), S105… Fifth step (Forming process), S108… Eighth step (Gap adjustment process), X… Width direction, Y… Depth direction, Z… Thickness direction

Claims

1. A panel forming device for forming panel end portions of a panel pre-formed into a narrowed shape, comprising: a lower die and an upper die; a cam pad for pressing a panel base portion inside the depth direction of the panel against the lower die, relative to the panel end portion of the panel; a pushing pad for pressing a constrained portion outside the depth direction of the panel end portion against the lower die; a pushing bending blade provided to move in conjunction with the upper die, for compressing the panel end portion between the lower die to form a recessed flange portion; and comprising: while the panel base portion is constrained by the lower die and the cam pad and the constrained portion of the panel end portion is constrained by the lower die and the pushing pad, moving the upper die relative to the lower die, so that the panel end portion is formed into the flange portion by the pushing bending blade; The pushing pad presses the constrained portion against the lower die so that the constrained portion is pulled by the load received by the constrained portion from the pushing bending blade until the forming of the panel end portion is completed, and escapes from between the lower die and the pushing pad to between the lower die and the pushing bending blade. A panel forming device.

2. The panel forming device according to claim 1, wherein the constrained portion of the panel end portion is pressed against the lower die over the entire width direction by the pushing pad, so as to be pre-deformed to reduce the difference in the width direction of the remaining machining amount by the pushing bending blade.

3. Based on the thickness of the constrained portion and the constraining force applied to the constrained portion pressed against the lower die by the pushing pad, the gap dimension between the lower die and the pushing pad at the time of constraining the constrained portion is preset so as to allow the constrained portion to escape from between the lower die and the pushing pad. The panel forming device according to claim 1 or 2.

4. The panel forming device according to claim 3, further comprising a gap setting mechanism portion capable of setting the gap dimension.

5. The gap setting mechanism portion includes a first block provided on the lower die and a second block provided on the pushing pad so as to be able to contact the first block. By changing the height of at least one of the first block and the second block, the gap dimension in a state where the first block and the second block are in contact is made variable. The panel forming device according to claim 4.

6. The panel forming device further comprises a pad holding mechanism portion interposed between the pushing pad and the pushing bending blade. The above-mentioned pushing pad is elastically held so as to be retractable at an initial position protruding from the pushing bending blade toward the lower die by the pad holding mechanism unit, and is configured to retract from the initial position to a retracted position by a reaction force received from the lower die during forming by the pushing bending blade. The panel forming apparatus according to claim 1 or 2.

7. The pad holding mechanism unit includes a rod attached to the pushing pad, a piston connected to the rod, and a cylinder that houses the piston and a working fluid and elastically biases the rod by utilizing a reaction force when the working fluid is compressed by the piston. The panel forming apparatus according to claim 6.

8. A panel forming method for forming a panel end portion of a panel that has been pre-drawn and formed, a restraining step of restraining a panel base portion inside the panel in the depth direction from the panel end portion of the panel with a lower die and a cam pad, and restraining a restrained portion on the outer side in the depth direction of the panel end portion with the lower die and a pushing pad; a forming step of moving an upper die relative to the lower die while restraining the panel base portion and the restrained portion, and compressing the panel end portion between the lower die and a pushing bending blade to form a recessed flange portion; comprising In the restraining step, the pushing pad presses the restrained portion against the lower die so that the restrained portion is pulled by a load received by the restrained portion from the pushing bending blade until the forming of the panel end portion is completed in the forming step, and the restrained portion slips out from between the lower die and the pushing pad to between the lower die and the pushing bending blade. A panel forming method.

9. In the restraining step, the restrained portion of the panel end portion is pressed against the lower die over the entire width direction by the pushing pad, and is pre-deformed so as to reduce the difference in the width direction of the remaining processing amount by the pushing bending blade in the forming step. The panel forming method according to claim 8.

10. Based on the thickness of the restrained portion and the restraining force applied to the restrained portion pressed against the lower die by the pushing pad, a gap setting step of presetting a gap dimension between the lower die and the pushing pad at the time of restraining the restrained portion so that the restrained portion slips out from between the lower die and the pushing pad. The panel forming method according to claim 8 or 9.

11. The panel forming method according to claim 10, comprising a gap adjustment step of adjusting the gap dimension according to the wrinkle generation situation in the flange portion.

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