Method for manufacturing frame component molded by roll-form molding, and frame component molded by roll-form molding

Abstract

The present invention comprises a cutting step S1 for cutting a plate material made of metal, and a molding step S2 for molding a frame component in which at least two closed-cross-section parts are arranged in succession by performing roll-form molding on the plate material. The present invention comprises a temporary joining step S3 for subjecting the frame component to temporary joining processing in which the shape of the closed-cross-section parts is maintained, a standby step S4 for causing the frame component for which the temporary joining processing has ended to stand by, and a main joining step S5 for welding the frame component waiting in the standby step. The temporary joining processing comprises holding plate materials in a state of being mechanically or chemically in close contact with each other. In the main joining step S5, an end part of a plate material is continuously welded to the plate material of a closed-cross-section part. When the frame component is being molded in the molding step S2, the welding of the main joining step S5 is performed on another frame component in the standby step S4.　Through the present invention, it is possible to provide a method for manufacturing a frame component molded by roll-form molding, capable of manufacturing a highly rigid frame component having a plurality of closed-cross-section parts with high productivity, and of suppressing spring back by a simple method to improve welding accuracy.

Description

Method for manufacturing a frame part formed by roll forming and a frame part formed by roll forming

[0001] The present invention relates to a method for manufacturing a roll-formed frame component and to a roll-formed frame component.

[0002] Components mounted on vehicles such as automobiles need to be supported by strong frame components. To increase the rigidity of the frame components, it is conceivable to provide the frame components with a closed cross-sectional portion in which multiple rectangular cross-sectional frames are arranged in a continuous line. Such a frame component is described, for example, in Patent Document 1. The frame component disclosed in Patent Document 1 uses multiple plate materials to form the closed cross-sectional portion. That is, the frame component is formed from a first plate material having a shaped portion with an S-shaped cross section, and second and third plate materials welded to both sides of the first plate material.

[0003] On the other hand, a frame component having multiple frames with a rectangular cross section is described, for example, in Patent Document 2. The frame component disclosed in Patent Document 2 is formed by bending a single sheet of plate material into a generally B-shaped cross section using roll forming. One end of the sheet material is butted against the other end at the bottom of the B and welded by high-frequency welding. Furthermore, the vertical middle portion of the B is formed to have a recess that opens toward the left side of the B. The bottom portion of this recess is made of overlapping plate material and spot-welded.

[0004] JP 2019-96385 A U.S. Patent No. 7,197,824

[0005] The frame part disclosed in Patent Document 1 has a problem in that forming a closed cross-section portion in which two frames with a rectangular cross section are lined up consecutively or three frames with a rectangular cross section is required a large number of manufacturing steps such as positioning and welding of multiple plate materials, resulting in low productivity.The frame part disclosed in Patent Document 2 has a recess formed in the middle part of the B-shape in the vertical direction, so it has insufficient rigidity and cannot be used as a frame for accommodating an automobile battery.

[0006] Furthermore, when welding one end and the other end of the plate material of the frame component shown in Patent Document 2 by high-frequency welding, a jig may be required to prevent the one end and the other end from separating due to springback and to improve welding accuracy. One possible jig is a box-shaped welding jig that sandwiches the frame component from both the left and right sides in a B-shape. Therefore, when manufacturing frame components by roll forming, there is a demand for a simple method to suppress springback and improve welding accuracy.

[0007] An object of the present invention is to provide a method for manufacturing a frame part formed by roll forming, which can produce highly rigid frame parts having multiple closed cross-sectional portions with high productivity, and which can suppress springback using a simple method to increase welding accuracy, and a frame part.

[0008] In order to achieve this object, the method of manufacturing a frame component formed by roll forming according to the present invention comprises a cutting step of cutting a metal plate material to a predetermined length, a forming step of forming a frame component having a long hollow body in which at least two closed cross-sectional portions are continuously arranged by applying roll forming to the plate material so as to surround one end of the plate material, a temporary joining step of performing a temporary joining process on the frame component to maintain the shape of the closed cross-sectional portions, a waiting step of making the frame component stand by after the temporary joining process, and a main joining step of welding the frame components standing by in the waiting step, The temporary joining process carried out in the temporary joining step is a joining process that mechanically or chemically holds at least one of the overlapping plate materials in a tight state to the extent that the shape of the closed cross-section portion of the frame part is maintained, and in the main joining step, one end formed in the early stage of the roll forming of the plate material or the other end formed in the final stage is continuously welded to the plate material of the closed cross-section portion along the longitudinal direction of the long hollow body, and while the frame part is being formed in the forming step, the welding in the main joining step is applied to the other frame part in the waiting step.

[0009] The frame part formed by roll forming according to the present invention is a frame part having a long hollow body in which at least two closed cross-section portions are lined up in succession by applying roll forming to a plate material, and has a tight contact portion where at least one overlapping plate material is joined to keep it in a mechanically or chemically tight state so that the shape of the closed cross-section portion is maintained in the frame part, and a weld portion which is continuously welded to the closed cross section along the longitudinal direction of the long hollow body at one end formed in the early stage of roll forming of the plate material or the other end formed in the final stage.

[0010] According to the present invention, it is possible to provide a method for manufacturing frame parts formed by roll forming, which can produce highly rigid frame parts having multiple closed cross-sectional portions with high productivity, and which can suppress springback using a simple method to increase welding accuracy, and a frame part.

[0011] FIG. 1 is a flowchart illustrating one embodiment of a method for manufacturing a frame component formed by roll forming according to the present invention. FIG. 2 is a side view of a roll forming machine. FIG. 3 is a block diagram showing a storage location and the configuration of the welding machine. FIG. 4 is a cross-sectional view of a frame component. FIG. 5 is a perspective view of a frame component. FIG. 6A is a cross-sectional view of a plate material showing the roll forming process in stages. FIG. 6B is a cross-sectional view of a plate material showing the roll forming process in stages. FIG. 6C is a cross-sectional view of a plate material showing the roll forming process in stages. FIG. 6D is a cross-sectional view of a plate material showing the roll forming process in stages. FIG. 6E is a cross-sectional view of a plate material showing the roll forming process in stages. FIG. 6F is a cross-sectional view of a plate material showing the roll forming process in stages. FIG. 6G is a cross-sectional view of a plate material showing the roll forming process in stages. FIG. 7A is a cross-sectional view of a plate material showing the roll forming process in stages. FIG. 7B is a cross-sectional view of a plate material showing the roll forming process in stages. FIG. 7C is a cross-sectional view of a plate material showing the roll forming process in stages. FIG. 7D is a cross-sectional view of a plate material showing the roll forming process in stages. FIG. 7E is a cross-sectional view of a plate material showing the roll forming process in stages. FIG. 8A is a cross-sectional view of a plate material showing the roll forming process in stages. FIG. 8B is a cross-sectional view of a plate material showing the roll forming process in stages. FIG. 8C is a cross-sectional view of a plate material showing the roll forming process in stages. FIG. 8D is a cross-sectional view of a plate material showing the roll forming process in stages. FIG. 9 is a cross-sectional view for explaining springback. FIG. 10 is a cross-sectional view of a frame component for which a temporary joining step has been performed. FIG. 11 is a flowchart showing a method for manufacturing a frame component including a drilling step. FIG. 12A is a cross-sectional view for explaining the temporary joining step. FIG. 12B is a cross-sectional view for explaining the temporary joining step. FIG. 12C is a cross-sectional view for explaining the temporary joining step. FIG. 13 is a cross-sectional view of a frame component compressed in a forming step. FIG. 14A is a front view showing the position of a rivet hole when compression deformation is restored. Fig. 14B is a front view showing the position of the rivet hole when the compressive deformation is restored. Fig. 15 is a cross-sectional view showing a modified example of the T-shaped joint.FIG. 16 is a cross-sectional view showing a modified example of a T-shaped joint. FIG. 17 is a flowchart showing a method for manufacturing a frame component having a groove forming step. FIG. 18A is a cross-sectional view illustrating the method for forming a groove. FIG. 18B is a cross-sectional view illustrating the method for forming a groove. FIG. 19 is a cross-sectional view illustrating the movement path of a groove when one end of a plate material is fitted into the groove. FIG. 20 is a flowchart showing a method for manufacturing a frame component having a step forming step. FIG. 21 is a cross-sectional view illustrating the shape of a melted portion formed by laser welding. FIG. 22 is a perspective view of a frame component after the main joining step has been completed. FIG. 23 is a perspective view of a frame component in which laser welding has been performed between multiple temporary joint portions. FIG. 24 is a side view of a roll forming machine for carrying out a method for manufacturing a frame component in which a cutting step is performed after a temporary joining step. FIG. 25 is a flowchart for explaining a method for manufacturing a frame component in which a cutting step is performed after a temporary joining step. FIG. 26 is a perspective view of a frame component that has been temporarily joined using clamps that clamp the overlapping portions of the plate materials. FIG. 27 is a front view of a frame component that has been temporarily joined using clamps that clamp the overlapping portions of the plate materials. FIG. 28 is a front view of frame parts that have been temporarily joined using clamps that clamp the entire frame parts. FIG. 29 is a cross-sectional view showing another example of a frame part. FIG. 30 is a cross-sectional view showing another example of a frame part having a groove into which one end of a plate material fits. FIG. 31 is a cross-sectional view showing another example of a frame part having a step into which one end of a plate material engages. FIG. 32 is a cross-sectional view showing another example of a frame part. FIG. 33 is a cross-sectional view for explaining springback. FIG. 34 is a cross-sectional view of a frame part that has been temporarily joined. FIG. 35 is a cross-sectional view of a frame part that has been compressed in a forming process. FIG. 36 is a cross-sectional view for explaining the shape of a penetration portion formed by laser welding. FIG. 37 is a perspective view of a frame part that has been joined after a main joining process has been completed. FIG. 38 is a perspective view of a frame part that has been laser welded between multiple temporary joint portions. FIG. 39 is a cross-sectional view of a frame part that has been temporarily joined using a flow drill screw. FIG. 40 is a cross-sectional view of a frame part immediately prior to being temporarily joined using a flow drill screw.FIG. 41 is a side view of a roll forming machine that performs temporary joining using a flow drill screw. FIG. 42 is a cross-sectional view of a frame component in a state where a flow drill screw has not been driven into a recessed portion. FIG. 43 is a cross-sectional view of a frame component in which a flow drill screw has been driven into a recessed portion. FIG. 44 is a cross-sectional view of a frame component in which a blind rivet has been attached to a recessed portion. FIG. 45 is a flowchart for explaining a method of manufacturing a frame component in which a recessed shape forming step is performed before a molding step. FIG. 46 is a flowchart for explaining a method of manufacturing a frame component in which a recessed shape forming step is performed during a molding step. FIG. 47 is a perspective view of a frame component that has been welded through the portion that has been temporarily joined. FIG. 48 is an enlarged cross-sectional view of a portion of a frame component that has been welded through the portion that has been temporarily joined. FIG. 49 is a cross-sectional view showing another example of a frame component. FIG. 50 is a cross-sectional view showing another example of a frame component.

[0012] (First embodiment) A method for manufacturing a frame component formed by roll forming according to the present invention will now be described in detail with reference to Figures 1 to 23. (Outline of the method for manufacturing a frame component) The method for manufacturing a frame component formed by roll forming according to this embodiment is a method that performs a cutting step S1, a forming step S2, a temporary joining step S3, a waiting step S4, and a main joining step S5 in this order, as shown in the flowchart of Figure 1. Frame components manufactured by this manufacturing method can be used as components for supporting on-board components of an automobile or the like (not shown), or as components that form part of the frame of the vehicle body.

[0013] The cutting process S1, the forming process S2, and the temporary joining process S3 are performed by a roll forming machine 1 shown in FIG. 2. The waiting process S4 is performed in a storage location 2 (see FIG. 3), and the main joining process S5 is performed by a main welding machine 3 (see FIG. 3). The roll forming machine 1 feeds a metal plate material 5 to the right in FIG. 1 from a cutting device 4 located at the far left in FIG. 2 to manufacture a product of a predetermined shape. The cutting device 4 is a device for performing the cutting process S1. This cutting device 4 has the function of cutting a metal plate material 5 having a predetermined width to a predetermined length, the function of performing drilling, groove forming, press working, etc. on the plate material 5, and the function of feeding the plate material 5 downstream in the feed direction.

[0014] A multi-stage roll forming machine 6 is disposed downstream of the cutting device 4 in the feed direction of the plate material 5, and a temporary joining device 7 is disposed downstream of the multi-stage roll forming machine 6 in the feed direction of the plate material 5. The multi-stage roll forming machine 6 is a device for performing the forming step S2. In this embodiment, the multi-stage roll forming machine 6 corresponds to the "roll forming device" as defined in the present invention. This multi-stage roll forming machine 6 uses multiple rolls 6a to bend the plate material 5 into a predetermined shape by roll forming, forming the frame component 8 shown in Figures 4 and 5. Figure 4 shows a cross-sectional view of the frame component 8 cut along an imaginary plane A shown in Figure 5. The imaginary plane A shown in Figure 5 is hatched downward to the left. The frame component 8 has a hollow body 8A formed to be elongated, as will be described in detail later. Roll forming will be described later.

[0015] The temporary joining device 7 is a device for performing the temporary joining step S3. This temporary joining device 7 performs a temporary joining process to maintain the shape of the frame component 8 formed by the multi-stage roll forming machine 6. The temporary joining process performed in the temporary joining step S3 is a joining process that maintains at least one pair of overlapping plate materials 5 in a mechanically or chemically intimate state to such an extent that the shape of a closed cross-sectional portion (described later) of the frame component 8 is maintained. The temporary joining device 7 according to this embodiment is configured with a rivet driving device 9. The temporary joining process according to this embodiment is riveting the overlapping portions of the plate materials 5. A detailed description of the temporary joining process will be given later.

[0016] After the temporary joining process by the temporary joining device 7 is completed, the frame components 8 are removed from the roll forming machine 1 and transferred to the storage location 2. The multi-stage roll forming machine 6 continuously produces frame components 8 that have been temporarily joined. For this reason, as shown in FIG. 3 , a plurality of frame components 8 are stored in the storage location 2 to await processing in the next process, the permanent joining process S5. The process in which the frame components 8 await the next process in the storage location 2 is the waiting process S4. In the permanent joining process S5, the frame components 8 waiting in the storage location 2 are supplied to the permanent welding machine 3, and permanent joining is performed on the frame components 8 to prevent changes in shape. In the permanent joining process S5 in this embodiment, laser welding is performed. A detailed description of laser welding will be given later.

[0017] (Specific Description of Frame Component Manufacturing Method) (Description of Forming Step S2) The frame component 8 shown in Fig. 4 is formed by roll forming a sheet material 5 so as to surround one end 11 of the sheet material 5. By performing roll forming in this manner, a T-joint 12 having a T-shaped cross section is formed against which one end 11 of the sheet material 5 abuts. The T-joint 12 is laser welded in the main joining step S5, as will be described in detail later. In describing each part of the frame component 8, for convenience, the upper side of Fig. 4 will be referred to as the upper part of the frame component 8, and the left side of Fig. 4 will be referred to as the left side of the frame component 8.

[0018] The roll forming according to this embodiment is carried out to form a first closed cross-sectional portion 13 and a second closed cross-sectional portion 14 that sandwich a T-shaped joint 12, and a third closed cross-sectional portion 15 that is located below the frame component 8 shown in Figure 4. When forming the first to third closed cross-sectional portions 13 to 15, a ladle-shaped portion 16 having a ladle-like cross section and including one end 11 of the plate material 5 is first formed at the beginning of the roll forming. The ladle-shaped portion 16 has one end 11 of the plate material 5 and is composed of a first horizontal wall 21 that extends from the one end 11 to the left in Figure 4, a first vertical wall 22 that extends downward from the left end of the first horizontal wall 21, a second horizontal wall 23 that extends to the right from the lower end of the first vertical wall 22, and a second vertical wall 24 that extends downward from the right end of the second horizontal wall 23. The ladle-shaped portion 16 is formed so that one end 11 of the plate 5 is located at the open end of the ladle, the first vertical wall 22 forms the bottom of the ladle, and the second vertical wall 24 forms the handle of the ladle.

[0019] Because the frame component 8 according to this embodiment has three closed cross-sectional portions (first to third closed cross-sectional portions 13 to 15), after the ladle-shaped portion 16 is formed, the outer peripheral frame 17 is formed so as to cooperate with the ladle-shaped portion 16 to form the first to third closed cross-sectional portions 13 to 15. The outer peripheral frame 17 includes an outer frame portion 18 having a cup-shaped cross section that accommodates the ladle of the ladle-shaped portion 16. The outer frame portion 18 cooperates with the ladle of the ladle-shaped portion 16 to form the two closed cross-sectional portions (first and second closed cross-sectional portions 13, 14) that sandwich the T-shaped joint. That is, the forming step S2 is performed so that the wall (first lateral wall 21) having one end 11 of the plate material 5 is shared by the two closed cross-sectional portions (first closed cross-sectional portion 13 and second closed cross-sectional portion 14) and serves as the boundary between the two closed cross-sectional portions.

[0020] The outer peripheral frame 17 is formed so as to surround the ladle-shaped portion 16 from the lower end of the second vertical wall 24 (the tip of the handle of the ladle), passing through the bottom side of the ladle and the opening side of the ladle. More specifically, the outer peripheral frame 17 is formed by a third horizontal wall 25 extending leftward from the lower end of the second vertical wall 24, a third vertical wall 26 extending upward from the left end of the third horizontal wall 25 and overlapping with the first vertical wall 22, a fourth horizontal wall 27 extending rightward from the upper end of the third vertical wall 26, and a fourth vertical wall 28 extending downward from the right end of the fourth horizontal wall 27 and overlapping with one end 11 of the plate material 5 and the second vertical wall 24. In this embodiment, the fourth vertical wall 28 corresponds to the "other end" as defined in the present invention. The outer frame portion 18 is composed of a third vertical wall 26 , a fourth horizontal wall 27 , and a fourth vertical wall 28 .

[0021] The forming sequence when the frame component 8 shown in Fig. 4 is formed by the roll forming method is, for example, as shown in Fig. 6A to Fig. 6G, Fig. 7A to Fig. 7D, and Fig. 8A to Fig. 8D. The roll forming is performed by the multi-stage roll forming machine 6 of the roll forming machine 1 shown in Fig. 1. Fig. 6A to Fig. 6G, Fig. 7A to Fig. 7D, and Fig. 8A to Fig. 8D are cross-sectional views of the plate material 5 as viewed from the longitudinal direction.

[0022] To form the frame component 8, the ladle-shaped portion 16 is first formed as shown in FIGS. 6A to 7B. Specifically, the first horizontal wall 21, which includes one end 11 of the flat plate material 5, is bent, and then the first vertical wall 22, the second horizontal wall 23, and the second vertical wall 24 are formed in this order. In this embodiment, the first horizontal wall 21 corresponds to the "one end" in the present invention. The radius of curvature of the curved portion 29 (see FIG. 4) between each wall can be adjusted by the multi-stage roll forming machine 6 depending on the rigidity and crashworthiness. Then, as shown in FIGS. 7C to 8D, the third horizontal wall 25, the third vertical wall 26, the fourth horizontal wall 27, and the fourth vertical wall 28 are formed in this order.

[0023] More specifically, in the step shown in Fig. 7D, the third vertical wall 26 and the first vertical wall 22 are overlapped to form a double wall. Then, in the steps shown in Figs. 8A and 8B, the third vertical wall 26 is bent while forming a curved portion 29 to form a fourth horizontal wall 27. Thereafter, in the steps shown in Figs. 8C and 8D, the fourth vertical wall 28 is overlapped with one end 11 of the plate material 5 and the second vertical wall 24 to form the T-joint 12. Note that after overlapping the third vertical wall 26 with the first vertical wall 22 in the step shown in Fig. 7D, an additional step can be added in which the third vertical wall 26 is bent to the left in the figure to form a frame 17a with a square cross section at the upper left side of the outer peripheral frame 17 in the figure, as shown in Fig. 7E.

[0024] This rectangular cross-section frame 17a is formed by bending the third vertical wall 26 clockwise in the figure. Finally, the third vertical wall 26 is formed downward to overlap the portion bent to the left, adding a closed cross section to the outside. After forming the rectangular cross-section frame 17a in this manner, the third vertical wall 26 is bent so that its tip points to the right in the figure, resulting in the state shown in Figure 8B. When roll-forming is performed in this manner, springback occurs in the curved portion 29, which can cause the frame component 8 to deform after forming, as shown in Figure 9. If springback occurs, the fourth vertical wall 28 separates from the one end 11 of the sheet material 5 and the second vertical wall 24, and the first vertical wall 22 separates from the third vertical wall 26. Such deformation would prevent laser welding of the T-shaped joint 12 in a subsequent process. To prevent such deformation due to springback, a temporary joining process S3 is performed after the forming process S2.

[0025] (Explanation of Temporary Joining Step S3) The temporary joining step S3 is performed by performing a temporary joining process on at least a first overlapping portion 31 (see FIG. 4 ) where the outer frame portion 18 (third vertical wall 26) overlaps with the bottom of the ladle (first vertical wall 22) of the ladle-shaped portion 16, and a second overlapping portion 32 where the outer frame portion 18 (fourth vertical wall 28) overlaps with the handle of the ladle (second vertical wall 24). In this embodiment, the temporary joining step S3 is performed using a rivet driving device 9 installed downstream in the feed direction of the frame component 8 from the multi-stage roll forming machine 6 that performs the forming step S2.

[0026] As shown in Figure 10, the rivet driving device 9 performs riveting using blind rivets 33. Figure 10 is a cross-sectional view of the frame component 8 shown in Figure 5 when cut along imaginary plane B. Imaginary plane B shown in Figure 5 is hatched downward to the right. Riveting is performed by inserting blind rivets 33 into rivet holes 34 in the frame component 8 from outside the frame component 8. The rivet holes 34 can be drilled at predetermined positions in the plate material 5 by the cutting device 4. That is, the cutting step S1 in this embodiment is performed including a drilling step S1A for drilling rivet holes 34, as shown in Figure 11.

[0027] The rivet holes 34 are composed of outer rivet holes 34a formed in the outer frame portion 18 (third and fourth vertical walls 26, 28) of the frame component 8 and inner rivet holes 34b formed in the first and second vertical walls 22, 24. The diameter of the outer rivet hole 34a is larger than the diameter of the inner rivet hole 34b. As shown in FIGS. 12A to 12C , the blind rivet 33 is composed of a cylindrical main body 35 and a shaft 36 inserted movably into the main body 35. A flange 35a is provided at one end of the main body 35. The shaft 36 penetrates the main body 35. The end of the shaft 36 protruding opposite the flange 35a of the main body 35 is provided with a head 36a whose outer diameter is equal to the outer diameter of the main body 35.

[0028] To perform the temporary joining step S3 using this blind rivet 33, first, as shown in Figure 12A, the blind rivet 33 is inserted into the rivet hole 34 from the outside of the frame component 8, and the shaft portion 36 is pulled toward the outside of the frame component 8 with the flange 35a pressed against the third and fourth vertical walls 26, 28. By pulling the shaft portion 36 in this manner, the tip 35b of the body portion 35 is spread apart by the head portion 36a, as shown in Figure 12B. The shaft portion 36 is then pulled a further predetermined length until the tip 35b of the body portion 35 is significantly deformed as shown in Figure 12C, and the shaft portion 36 is then cut off at the portion protruding from the flange 35a. By performing the temporary joining process in this manner, subsequent deformation due to springback is restricted, and one end 11 of the plate material 5 is held in abutment against the fourth vertical wall 28 at the T-shaped joint 12.

[0029] Springback begins when forming by the multi-stage roll forming machine 6 is completed. Therefore, springback that occurs before the temporary joining process is performed may cause misalignment between the outer rivet holes 34a and the inner rivet holes 34b. In this embodiment, the outer rivet holes 34a are formed with a larger diameter than the inner rivet holes 34b, which allows for a wider tolerance for misalignment due to springback.

[0030] To prevent springback that occurs before the temporary joining process from misaligning the outer rivet holes 34a with the inner rivet holes 34b, it is possible to apply a forming stress during roll forming so that the frame component 8 is compressed and deformed from its normal shape. That is, when forming the outer rim 17 of the frame component 8, a portion of the frame component 8 is elastically deformed as shown in FIG. 13, and the frame component 8 is formed so that the normal shape is restored during the springback process due to stress release after forming. In the frame component 8 shown in FIG. 13, the first and second side walls 21, 23 of the ladle-shaped portion 16 are tilted downward to the right, and the lower portion of the frame component 8 is deformed as if crushed in the left-right direction due to compression. In FIG. 13, the frame component 8 is depicted as being deformed more than it actually is to make the deformation easier to understand.

[0031] By performing roll forming in this way, taking into consideration stress relief after forming, the frame component 8 returns to its normal shape, i.e., the shape shown in Figure 4, due to springback caused by stress relief after forming. When the frame component 8 is compressively deformed by roll forming, there is a misalignment between the outer rivet holes 34a and the inner rivet holes 34b immediately after forming, as shown in Figure 14A. However, once the frame component 8 returns to its normal shape due to springback, the misalignment between the outer rivet holes 34a and the inner rivet holes 34b is eliminated, as shown in Figure 14B. By performing a temporary joining process at this time, riveting using the blind rivet 33 is performed correctly.

[0032] To perform riveting in this manner, the temporary joining device 7 may be positioned so that the frame components 8 return to their normal shape while being sent from the multi-stage roll forming machine 6 to the temporary joining device 7. To achieve this, it is conceivable to set the distance D (see FIG. 2 ) between the multi-stage roll forming machine 6 and the temporary joining device 7 to the distance that the frame components 8 move after forming until they return to their normal shape. By adopting this configuration, the temporary joining process can be performed when the frame components 8, which have been compressively deformed by roll forming, return to their normal shape due to springback caused by stress release.

[0033] When compressively deforming the frame component 8 by roll forming, the configurations shown in Figures 15 and 16 can be considered to ensure that the one end 11 of the plate material 5 abuts against the fourth vertical wall 28 at the T-joint 12 during the restoration process of the frame component 8. The T-joint 12 shown in Figure 15 is configured so that the one end 11 of the plate material 5 fits into a groove 37 formed in the fourth vertical wall 28. The groove 37 shown in Figure 15 is formed by a guide shape portion 38 continuing to the inner side surface 28a of the fourth vertical wall 28 and a groove bottom portion 39 connected to the guide shape portion 38. The guide shape portion 38 is formed by an inclined surface extending from the side surface 28a toward the inside of the groove 37. The inclined surface is inclined so that the opening width of the groove 37 gradually widens toward the outside of the groove 37. The groove bottom 39 is made up of a side surface 39a extending in the depth direction of the groove 37 and a bottom surface 39b that forms the groove bottom, and is formed so that the cross section has an angular C-shape. The groove width of the groove bottom 39 is a width that fits into one end 11 of the plate material 5.

[0034] The grooves 37 shown in Fig. 15 can be formed by cutting or molding. The groove forming step of forming the grooves 37 in the fourth vertical wall 28 by cutting or molding is performed before the sheet material 5 is roll-formed in the molding step S2. For example, as shown in Fig. 17, the groove forming step S6 can be performed between the cutting step S1 and the molding step S2. When the grooves 37 are formed by cutting, a rotating cutting tool 41 is pressed against the sheet material 5 as shown in Fig. 18A. The cutting tool 41 can be provided in the cutting device 4, or can be arranged between the cutting device 4 and the multi-stage roll forming machine 6.

[0035] When the grooves 37 are formed by molding, a groove-forming roll 42 is pressed against the sheet material 5 as shown in FIG. 18B . The groove-forming roll 42 can be provided at a position before the roll forming of the multi-stage roll forming machine 6 is performed. A groove processing portion 43 is provided on the outer periphery of the roll 42. By pressing the roll 42 against the sheet material 5 and rotating it, the shape of the groove processing portion 43 is transferred to the sheet material 5, forming the grooves 37. Note that the grooves 37 are formed so that a portion of the inner surface (side surface 28 a) of the fourth vertical wall 28 is recessed, but a convex shape may be exposed on the outer surface of the portion where this recess is formed. Such an exposed convex shape serves as a mark for laser welding.

[0036] In the T-joint 12 shown in Figure 15, as the fourth vertical wall 28 approaches the one end 11 of the plate material 5 by roll forming, a corner 44 of the one end 11 fits into a corner 45 of the groove bottom 39 immediately after passing through the guide shape portion 38, as shown in Figure 19. The fourth vertical wall 28 then tilts clockwise in the figure around this corner 45, and the one end 11 of the plate material 5 fits into the groove bottom 39. By fitting the one end 11 of the plate material 5 into the groove 37 in this way, the T-joint 12 in its final shape is formed.

[0037] The T-shaped joint 12 shown in Figure 16 has a structure in which one end 11 of the plate material 5 engages with a step 46 formed in the fourth vertical wall 28. The step 46 is formed in the fourth vertical wall 28 so that a portion of it is positioned offset to one side in the thickness direction. The step 46 shown in Figure 16 is formed so that the portion of the fourth vertical wall 28 that is located above the one end 11 of the plate material 5 is offset to the left. This step 46 can be formed by press molding using the press function of the cutting device 4.

[0038] The step forming step of forming the step 46 in the fourth vertical wall 28 is performed before the roll forming of the plate material 5 in the forming step S2. For example, as shown in Figure 20, the step forming step S7 can be performed between the cutting step S1 and the forming step S2. The one end 11 of the plate material 5 engages with the step 46 formed in the fourth vertical wall 28, thereby forming the T-shaped joint 12 in its final shape.

[0039] (Description of the Final Joining Process S5) The final joining process S5 is performed by sequentially feeding the frame components 8 that have been temporarily joined and transferred to the storage location 2 into the final welding machine 3. That is, in the final joining process S5, while the frame components 8 are being formed in the forming process S2, laser welding is performed on the other frame components 8 waiting in the waiting process S4 (other frame components 8 in the waiting process S4). Laser welding is performed consistently using the same welding method on the frame components 8 waiting in the waiting process S4. In the final joining process S5, it is desirable to simultaneously laser weld multiple frame components 8 using multiple final welding machines 3. This is because laser welding, which regulates the cross-sectional shape of frame components with two closed cross sections on both sides of a T-shaped joint, requires a longer operation time than roll forming, and therefore, simultaneous laser welding of multiple frame components 8 can increase productivity. As shown in FIG. 21 , laser welding is performed by irradiating the T-shaped joint 12 with laser light L from the outside of the frame components 8 (from the opposite side of the first lateral wall 21). Although FIG. 21 shows the T-junction 12 when the groove 37 is used, the same applies when the groove 37 is not used.

[0040] The laser beam L is irradiated onto the outer surface 28b of the fourth vertical wall 28 at a position corresponding to the first horizontal wall 21 (one end 11 of the plate material 5). By irradiating the T-joint 12 with the laser beam L in this manner, a portion of the fourth vertical wall 28 and a portion of the first horizontal wall 21 melt and mix together, welding them together. Laser welding creates a warhead-shaped melted portion 47, shown by hatching slanting downward to the left in FIG. 21 . The warhead shape of the melted portion 47 is a convex shape extending from the laser irradiation surface (outer surface 28b) toward the first horizontal wall 21. The warhead-shaped melted portion makes the first horizontal wall 21 more likely to collapse under a load from the laser irradiation direction. The collapse of the first horizontal wall 21 facilitates load concentration on the curved portion 29, increasing the amount of shock absorption.

[0041] Laser welding is performed continuously from one longitudinal end to the other longitudinal end of the frame component 8, as shown by the reference numeral 48 in Fig. 22. Completion of the main joining step S5 completes a frame component 51 in its final shape, with deformation of the shape being restricted. Laser welding can also be performed at a position longitudinally adjacent to the blind rivet 33 driven by the rivet driving device 9 in the temporary joining step S3 on the frame component 8, as shown in Fig. 23. Laser welding has been performed on the frame component 8 shown in Fig. 23 so that linear welds 52 are formed between a plurality of temporary joining treatment portions (blind rivets 33) lined up at predetermined intervals in the longitudinal direction.

[0042] (Explanation of effects of the first embodiment) The manufacturing method of frame components formed by roll forming according to this embodiment includes a cutting process S1 in which a metal plate material 5 is cut to a predetermined length, a forming process S2 in which the plate material 5 is roll formed to form a frame component 8 having a T-shaped cross-section joint 12 and first, second closed cross-sectional portions 13, 14 and a third closed cross-sectional portion 15 sandwiching the T-shaped cross-section joint 12, a temporary joining process S3 in which a temporary joining process is performed to maintain the shape of the frame component 8, a waiting process S4 in which the frame component 8 is made to wait, and a final joining process S5 in which final welding is consistently performed on the frame components 8 waiting in the waiting process S4, and while the frame components 8 are being formed in the forming process S2, final welding is performed on the other frame components 8 in the waiting process S4.

[0043] This manufacturing method allows for the formation of multiple adjacent closed cross sections (first and second closed cross section portions 13, 14) sandwiching the T-shaped joint 12, thereby enabling the manufacture of a highly rigid frame component 51. This frame component 51 can be used as a side frame of a battery case that houses a battery for an electric vehicle. Because the temporary joining process is performed after roll forming, the frame component 8 will not be deformed by springback even if the waiting step S4 is performed after roll forming. Therefore, the accuracy of the actual welding after roll forming can be improved using a simple method that does not require a box-type welding jig or the like.

[0044] Since the joining (laser welding) time required to regulate the cross-sectional shape of a frame component having two closed cross sections on both sides of a T-shaped joint is longer than the time required for roll forming, providing a waiting step S4 makes it possible to produce the frame without reducing the roll forming speed, thereby improving productivity. Therefore, according to this embodiment, it is possible to provide a method for manufacturing a frame component formed by roll forming that can produce highly rigid frame components having multiple closed cross sections with good productivity, and that can suppress springback with a simple technique to increase welding accuracy.

[0045] The frame component 8 formed by the frame component manufacturing method according to this embodiment has a ladle-shaped portion 16 having a ladle-shaped cross section with one end 11 of the plate material 5 located at the open end of the ladle, and an outer frame portion 18 having a cup-shaped cross section that accommodates the ladle and that cooperates with the ladle to form two closed cross-sectional portions (first and second closed cross-sectional portions 13, 14) that sandwich a T-shaped joint. The temporary joining step S3 is performed by performing a temporary joining process on at least the portion where the outer frame portion 18 overlaps the bottom of the ladle and the portion where the outer frame portion 18 overlaps the handle of the ladle.

[0046] In this embodiment, a drilling step S1A is performed prior to the forming step S2, drilling rivet holes 34 in the sheet material 5 at positions where temporary joining processing will be performed. The temporary joining step S3 is performed by driving blind rivets 33 into the rivet holes 34 using a rivet driving device 9 installed downstream in the feed direction of the frame components 8 from the multi-stage roll forming machine 6 that performs the forming step S2. Because roll forming can form complex closed cross sections, it is easy to create complex closed cross sections, including T-shaped joints 12. However, areas that cannot be overbended are in a state of compressive deformation of the cross section, and therefore will return to their original position due to springback. Therefore, these areas are temporarily joined by a temporary joining process. In other words, the bending points around the T-shaped joint 12 (the connection between the second vertical wall 24 and the third horizontal wall 25, and the connection between the fourth horizontal wall 27 and the fourth vertical wall 28) cannot be overbended after the T-shaped joint 12 is formed, so springback may cause them to open up more than their normal positions. Therefore, springback can be suppressed by configuring the opening of the ladle as a T-shaped joint 12 and performing a temporary joining process on the part that will become the bottom of the ladle and the part that will become the handle. A complex closed cross section including the T-shaped joint 12 cannot be temporarily joined by pinch spot welding, but one-sided joining is possible by using a rivet. Furthermore, even when temporary joining is performed on both sides of the frame component 8, the rivets can be driven from both sides of the frame component 8 using the rivet driving device 9, so the time required for temporary joining can be shortened. By performing temporary joining on both sides of the frame component 8, the strength of the temporary joint is stabilized.

[0047] The roll forming in the forming step S2 according to this embodiment is considered to apply forming stress so as to compressively deform the frame components 8. The temporary joining process in the temporary joining step S3 is performed when the frame components 8 have restored to their normal shape due to springback caused by stress release. According to this embodiment, laser welding can be performed on the frame components 8 in their normal shape in the main joining step S5, making it possible to manufacture high-quality frame components.

[0048] In this embodiment, when a groove 37 into which the one end 11 of the plate material 5 is fitted is formed in the plate material 5 and the one end 11 of the plate material 5 is fitted into the groove 37 in the forming step S2, it is possible to prevent the T-shaped joint 12 from being broken due to spring back. In addition, fitting can be performed while performing roll forming within a closed cross section.

[0049] In this embodiment, when the step 46 is formed in the plate material 5 so that a portion of the plate material 5 is positioned offset to one side in the thickness direction and the one end 11 of the plate material 5 is engaged with the step 46 in the forming step S2, it is possible to prevent the T-shaped joint 12 from being broken due to spring back. Also, it is possible to perform the engagement while performing roll forming within a closed cross section.

[0050] In this embodiment, the temporary joining process in the temporary joining step S3 is performed in a state where the T-shaped joint 12 is formed into its final shape, so that the product shape of the closed cross section adjacent to the T-shaped joint 12 can be maintained.

[0051] The main joining step S5 in this embodiment is performed by laser welding the T-joint 12 from the outside of the frame component 8. Although the T-joint 12 is located inside the closed cross section, laser welding allows welding from one side of the frame component 8. Therefore, a frame component with high rigidity can be manufactured.

[0052] In this embodiment, when laser welding is also performed on the rivet and the frame part 8 at a position adjacent in the longitudinal direction, it is possible to reliably prevent the shape of the final product from being changed.

[0053] Second Embodiment The cutting step S1 can be performed after the molding step S2. An embodiment employing this configuration will be described with reference to Figures 24 and 25. In Figures 24 and 25, components that are the same as or equivalent to those described with reference to Figures 1 to 23 are designated by the same reference numerals, and detailed description thereof will be omitted.

[0054] The method for manufacturing a frame part formed by roll forming in this embodiment is carried out using a roll forming machine 61 shown in Fig. 24, as shown in the flowchart of Fig. 25. The roll forming machine 61 feeds a metal sheet 5 from an uncoiler 62 located at the far left in Fig. 24 to the right in Fig. 24, and produces a product of a predetermined shape. The metal sheet 5 is attached to the uncoiler 62 in a coiled state.

[0055] Downstream of the uncoiler 62 in the feeding direction of the sheet material 5, devices such as a pre-hole press 63, a multi-stage roll forming machine 64, a temporary joining device 65, and a cutting machine 66 are arranged in this order. The pre-hole press 63 performs machining processes such as drilling, cutting, and pressing on the sheet material 5. The rivet holes 34, grooves 37, step portions 46, etc. can be formed by this pre-hole press 63.

[0056] The cutting machine 66 cuts the cylindrically formed plate material 5 to a predetermined length after the temporary joining process. The cutting machine 66 cuts the plate material 5 to form frame components 8 that will become frame components 51. The frame components 8 are sent to the storage location 2 shown in FIG. 3 and sequentially fed into the welding machine 3. When this configuration is adopted, as shown in FIG. 23 , the cutting process S1 is performed after the forming process S2 and the temporary joining process S3 are completed, and then the waiting process S4 and the final joining process S5 are performed sequentially. That is, the cutting process S1 is performed either after the temporary joining process S3 but before the waiting process S4 as shown in this embodiment, or before the forming process S2 as in the above-described embodiment. By performing the cutting process S1 after the temporary joining process S3, the cylindrically formed plate material 5 can be cut while suppressing deformation due to springback.

[0057] (Third embodiment with different temporary joining process) When the first embodiment is adopted, the temporary joining process is performed using blind rivets 33. However, the temporary joining process can also be performed using clamps 71, 72 as shown in Figures 26 to 28. In Figures 26 to 28, components that are the same as or equivalent to those described with reference to Figures 1 to 23 are given the same reference numerals, and detailed descriptions thereof will be omitted where appropriate.

[0058] The frame component 8 shown in Fig. 26 is formed in the forming step S2 from plate materials 5 cut to a predetermined length before the forming step S2, and has clamps 71 attached to both longitudinal ends. As shown in Fig. 27, the clamps 71 clamp the overlapping portions of the plate materials 5 in the thickness direction, holding the plate materials 5 in close contact with each other. The clamps 71 shown in Fig. 27 are attached to the overlapping portions of the first vertical wall 22 and the third vertical wall 26 of the frame component 8, and to the overlapping portions of the second vertical wall 24 and the fourth vertical wall 28 of the frame component 8, respectively.

[0059] The clamp 72 shown in Figure 28 corresponds to the "clamping member" of the present invention and is configured to clamp and bind one outer end 8a (left end) and the other outer end 8b (right end) of the frame components 8 so that the other end 73 (the lower end of the fourth vertical wall 28) of the plate material 5 is clamped between them. The temporary joining process using the clamp 72 shown in Figure 28 can be performed even when the plate material 5 has not yet been cut into the individual frame components 8, or can be performed even after the plate material 5 has been cut into the individual frame components 8. In other words, the temporary joining process using the large clamp 72 shown in Figure 28 can be performed either when the cutting step S1 is performed before the forming step S2, or when the cutting step S1 is performed after the temporary joining step S3 and before the waiting step S4.

[0060] (Fourth embodiment with different frame components) In the above-described embodiments, an example has been shown in which a frame component 8 having first to third closed cross-sectional portions 13 to 15 is formed by roll forming. However, the present invention is also applicable to a case in which a frame component 83 having only first and second closed cross-sectional portions 81, 82 located on both sides of a T-shaped joint 12 is formed by roll forming, as shown in Figures 29 to 31. In Figures 29 to 31, components that are the same as or equivalent to those described in Figures 1 to 28 are designated by the same reference numerals, and detailed descriptions thereof will be omitted where appropriate.

[0061] 29 to 31 , the frame component 83 is formed by forming the first horizontal wall 21, the first vertical wall 22, and the second horizontal wall 23, and then bending the plate material 5 upward to form a fifth vertical wall 84 so that it overlaps with the tip of the first horizontal wall 21 (one end 11 of the plate material 5). Then, a fifth horizontal wall 85 is formed parallel to the first horizontal wall 21, and then a sixth vertical wall 86 extending downward is formed. The lower end of the sixth vertical wall 86 becomes the other end of the plate material 5. This sixth vertical wall 86 is formed so as to overlap the first vertical wall 22. In this embodiment, a temporary joining process is performed in the temporary joining step S3 at an overlapping portion 87 where the first vertical wall 22 and the sixth vertical wall 86 overlap.

[0062] A groove 37 into which one end 11 of the plate material 5 fits is formed in a fifth vertical wall 84 of a frame component 83 shown in Figure 30. A step 46 into which one end 11 of the plate material 5 engages is formed in a fifth vertical wall 84 of a frame component 83 shown in Figure 31. Even when forming a frame component 83 having only first and second closed cross-sectional portions 81, 82 as shown in Figures 29 to 31, it is possible to productively manufacture highly rigid frame components having a plurality of closed cross-sectional portions as in the embodiment shown in Figures 1 to 28, and it is also possible to provide a method for manufacturing frame components formed by roll forming that is capable of suppressing springback by a simple technique and increasing welding accuracy.

[0063] In the above-described embodiment, the frame part 8 has an outer peripheral frame 17 formed to surround the ladle-shaped portion 16 from the tip of the handle of the ladle, passing through the bottom side and the opening side of the ladle. However, the frame part 8 may also surround the ladle-shaped portion 16 from the opening side and the bottom side of the ladle, and may have an opening, without being limited to the outer peripheral frame 17. For example, after forming the ladle-shaped portion 16, the outer frame part 18 is formed by roll forming in the order of the fourth vertical wall 28, the fourth horizontal wall 27, and the third vertical wall 26. The outer frame part 18 is formed in a cup-like cross section that opens downward and accommodates the ladle of the ladle-shaped portion 16, and forms two closed cross-sectional portions (first and second closed cross-sectional portions 13, 14) that sandwich the T-shaped joint 12 in cooperation with the ladle. In the above embodiment, the third closed cross-sectional portion 15 is provided on the left side of the ladle handle (second vertical wall 24), but it may also be provided on the right side of the ladle handle, and the fourth and fifth closed cross-sectional portions may be provided above and below or on the left and right. Also, although the ladle-shaped portion 16 is roll-formed clockwise, it may also be roll-formed counterclockwise.

[0064] Fifth Embodiment The present invention can be configured as shown in Figures 32 to 38. In Figures 32 to 38, components that are the same as or equivalent to those described with reference to Figures 1 to 31 are designated by the same reference numerals, and detailed description thereof will be omitted. The frame component 101 shown in Figure 4 is identical in configuration to the frame component 8 shown in the first embodiment, except for the configuration of one end portion 102, which is formed first in the roll forming process. That is, this frame component 101 has a hollow body 101A formed to be elongated. This frame component 101 can be manufactured by the manufacturing method shown in Figure 1. The one end portion 102 is formed to overlap the fourth vertical wall 28 of the frame component 8 in the thickness direction, forming a double wall.

[0065] In the frame part 101 according to this embodiment, a single plate material 5 is bent by roll forming, so that plate-like portions that are parts of the plate material 5 overlap each other in the thickness direction at three locations. The frame part 101 shown in Fig. 32 is provided with first to third double wall portions 103 to 105, in which parts of the plate material 5 are aligned in a direction perpendicular to the direction in which the first to third closed cross-sectional portions 13 to 15 are aligned (the left-right direction in Fig. 4).

[0066] The first double wall portion 103 includes one end portion 102 that is formed in the initial stage of roll forming. The second double wall portion 104 includes another end portion 106 that is formed in the final stage of roll forming. The one end portion 102 and the other end portion 106 extend in the up-down direction of the frame component 101. The third double wall portion 105 is located between the first double wall portion 103 and the second double wall portion 104 in the up-down direction of the frame component 101. In this frame component 101, the second double wall portion 104 and the third double wall portion 105 are temporarily joined in a temporary joining process S3, and the first double wall portion 103 is laser welded in a main joining process S5.

[0067] The roll forming according to this embodiment is carried out to form first and second closed cross-sectional portions 13, 14 including a first double-wall portion 103 and a third double-wall portion 105, and a third closed cross-sectional portion 15 including a second double-wall portion 104. When forming the first to third closed cross-sectional portions 13 to 15, as in the first embodiment, first, a ladle-shaped portion 16 having a ladle-shaped cross section including one end portion 102 of the sheet material 5 is formed in the early stage of roll forming. Subsequent forming is carried out in the same manner as in the first embodiment.

[0068] The forming sequence when the frame component 101 shown in Fig. 32 is formed by roll forming is the same as the forming sequence when the first embodiment is adopted, except that one end portion 102 is formed first in the roll forming. In this embodiment, too, a step can be added to form a frame 17a having a square cross section at the upper left side of the outer peripheral frame 17, as shown in Fig. 7E.

[0069] (Explanation of the temporary joining step S3 in the fifth embodiment) In this frame component 101, the fourth vertical wall 28, including the other end 106 of the plate material 5, is connected to the fourth horizontal wall 27 at a single bending point 107 located within the imaginary circle formed by a two-dot chain line in FIG. 34 . Therefore, warping due to springback is more likely to occur than in a wall sandwiched between two bending points (e.g., the third vertical wall 26). In particular, if one end 11 or the other end 108 (see FIG. 32 ) of the plate material 5 is outside the closed cross section when the final shape (a shape with two or three consecutive rectangular closed cross sections) is achieved, springback is likely to result in a shape that is more open than the normal shape. For this reason, the temporary joining process in the temporary joining step S3 is performed on the end portion located outside the closed cross section while maintaining at least the hollow shape of the frame component 101. In the frame part 101 according to this embodiment, the other end 106 is located outside the closed cross section, so that it is necessary to perform a temporary joining process on the second double wall portion 104 .

[0070] The temporary joining step S3 in this embodiment is carried out by using a rivet driving device 9 to perform temporary joining processing on the second double wall portion 104 and the third double wall portion 105, as in the first embodiment. In this embodiment, the second double wall portion 104 and the third double wall portion 105 correspond to the "close contact portion" of the present invention. By performing the temporary joining processing on the frame component 101, blind rivets 33 are driven into the second and third double wall portions 104, 105 as shown in Figure 34 through the steps shown in Figures 12A to 12C.

[0071] In the frame component 101 according to this embodiment, it is also possible to apply forming stress during roll forming so that the frame component 101 is compressed and deformed from its normal shape. That is, when forming the outer periphery 17 of the frame component 101, a portion of the frame component 101 is elastically deformed as shown in FIG. 35, and the frame component 101 is formed so that the normal shape is achieved during the springback process due to stress release after forming. In the frame component 101 shown in FIG. 35, the first and second lateral walls 21, 23 of the ladle-shaped portion 16 are inclined downward to the right, and the lower portion of the frame component 101 is deformed as if crushed in the left-right direction due to compression. In FIG. 35, the frame component 101 is depicted as being deformed more than it actually is to make the deformation easier to understand.

[0072] By performing roll forming in this way, taking into consideration stress relief after forming, the frame component 101 returns to its normal shape, i.e., the shape shown in Fig. 32, due to springback caused by stress relief after forming. By performing a temporary joining process when the shape has been restored in this way, riveting using blind rivets 33 can be performed correctly. In order to perform riveting in this way, it is possible to consider setting the distance D (see Fig. 2) between the multi-stage roll forming machine 6 and the temporary joining device 7 to the distance that the frame component 101 moves after forming until it returns to its normal shape.

[0073] (Explanation of Main Joining Step S5 According to Fifth Embodiment) The main joining step S5 performed in manufacturing the frame component 101 according to this embodiment is performed in the same manner as when the first embodiment is adopted. The laser welding performed in the main joining step S5 is performed by irradiating the first double wall portion 103 with laser light L from the outside of the frame component 101 (from the side opposite to the one end 102), as shown in Fig. 36 .

[0074] The laser beam L is irradiated onto the outer surface 28b of the fourth vertical wall 28 at a position corresponding to the one end 102. By irradiating the first double-wall portion 103 with the laser beam L in this manner, a portion of the fourth vertical wall 28 and a portion of the one end 102 melt and mix together, welding them together. Laser welding creates a warhead-shaped melted portion 47, shown by hatching slanting downward to the left in FIG. 36 . The warhead shape of the melted portion 47 is a convex shape extending from the laser irradiation surface (outer surface 28b) toward the one end 102. The warhead-shaped melted portion makes the first horizontal wall 21 more likely to collapse under a load from the laser irradiation direction. The collapse of the first horizontal wall 21 facilitates load concentration on the curved portion 29, increasing the amount of shock absorption.

[0075] As shown in Figure 37, laser welding is performed continuously so that a weld 48 extends from one end to the other end in the longitudinal direction of the frame component 101. When the main joining step S5 is completed, a frame component 111 is completed in its final shape, with deformation of the shape being restricted. Laser welding can also be performed at a position adjacent to the blind rivet 33 in the longitudinal direction of the frame component 101, as shown in Figure 38. Laser welding has been performed on the frame component 101 shown in Figure 38 so that linear welds 112 are formed between a plurality of temporary joint processing portions (blind rivets 33) lined up at predetermined intervals in the longitudinal direction.

[0076] (Explanation of the Effects of the Fifth Embodiment) When the frame component 8 according to the first embodiment is thick, it is easy to position it by fitting a T-shaped butt or groove. However, when the plate thickness is reduced to reduce weight, the material becomes more prone to bending, making the first horizontal wall 21 more likely to tilt. Furthermore, when the plate thickness is thin, the groove becomes shallow or is difficult to form, which may make positioning impossible. In this embodiment, the one end 102 of the plate material 5 is roll-formed to form a double wall with the fourth vertical wall 28, and the contact area between the one end 102 and the fourth vertical wall 28 is in surface contact. In other words, the contact area is larger than when welding is performed at the butt. This allows for easy and accurate welding of the first double wall portion 103.

[0077] Therefore, according to this embodiment, it is possible to provide a frame component formed by roll forming and a manufacturing method thereof, which can produce a highly rigid frame component 101 having a plurality of closed cross-sections with good productivity and can suppress springback by a simple technique to improve welding accuracy. Also in this embodiment, welding performed in the main joining step S5 can be performed on the second double-wall portion 104 instead of the first double-wall portion 103. That is, in the main joining step S5, one end 102 of the sheet material 5 in the initial stage of roll forming or the other end 106 in the final stage is continuously welded to the closed cross-section portion of the sheet material 5 along the longitudinal direction of the elongated hollow body 101A.

[0078] In manufacturing the frame component 101 according to this embodiment, the cutting step S1 can be performed before the molding step S2 as shown in Fig. 1, or the cutting step S1 can be performed after the molding step S2 as shown in Fig. 24 and Fig. 25. Furthermore, the temporary joining process performed on the frame component 101 can be performed using the blind rivets 33, or alternatively, the clamps 71 and 72 shown in Figs. 26 to 28 can be used.

[0079] Sixth Embodiment The temporary joining means for performing the temporary joining process can be implemented as shown in Figures 39 to 48. In Figures 39 to 48, components that are the same as or equivalent to those described with reference to Figures 1 to 38 are given the same reference numerals, and detailed descriptions will be omitted where appropriate. The frame component shown in Figures 39 to 48 is a frame component 101 when the fifth embodiment is adopted. However, although not shown, the temporary joining means according to this embodiment can also be used for the frame component 8 shown in Figure 4.

[0080] The close contact portion (second double-wall portion 104 and third double-wall portion 105) shown in Figure 39 is joined by a flow drill screw 121 (hereinafter simply referred to as FDS 121). The FDS 121 is a screw member that is pressed against the plate material 5 while rotating at high speed (see Figure 40). When the rapidly rotating FDS 121 is pressed against the plate material 5, the plate material 5 is softened by heat generated by friction between the FDS 121 and the plate material 5. The softened plate material 5 then undergoes plastic flow, forming a thread 122, and the FDS 121 is screwed into the plate material 5. The thread shape is then maintained by cooling, and the overlapping plate materials 5 are held in close contact with each other.

[0081] As shown in FIG. 41 , the temporary joining process S3 using the FDS 121 is performed by driving the FDS 121 using a flow drill screw driving device 123 installed downstream of the multi-stage roll forming machine 6 performing the forming process S2 in the feed direction of the frame component 101. In this case, the manufacturing method of the frame component 101 can be the manufacturing method shown in the flowcharts of FIGS. 1 and 25 . When using the FDS 121 in the temporary joining process S3, the number of steps can be reduced compared to temporary joining using blind rivets 33 because the step of drilling pilot holes (rivet holes 34) is unnecessary. Even when temporary joining is performed using the FDS 121, driving from one side is possible, and even closed cross sections can be joined. Furthermore, compared to laser welding (full welding), joining can be performed more quickly, allowing the frame components to maintain their normal shape more quickly. Furthermore, when driving the FDS 121 into the frame component 101 from both the left and right sides, the temporary joining time can be shortened.

[0082] Even in the case of the frame component 101 in which the close contact portions are joined by the FDS 121, the close contact portions are in a close contact state, and therefore laser welding is performed in a state in which the plate materials 5 are in close contact with each other at the first double wall portion 103. As a result, this frame component 101 also becomes a frame component with high welding strength.

[0083] When an FDS 121 or a blind rivet 33 is used as the temporary joining means for the temporary joining process, a recessed portion 124 can be formed in the second and third double wall portions 104, 105 where the temporary joining process is performed in the plate material 5, as shown in Figure 42. An FDS 121 can be driven into the recessed portion 124 as shown in Figure 43, or a blind rivet 33 can be driven into the recessed portion 124 as shown in Figure 44. A rivet hole 34 is pre-drilled in the recessed portion 124 shown in Figure 44, just as in the case where no recessed portion 124 is provided.

[0084] In the FDS 121 shown in Figure 43, the head 121a is housed in a recessed portion 124. The recessed portion 124 is shaped so that it can house the entire head 121a of the FDS 121. More specifically, as shown in Figure 42, the recess depth D of the recessed portion 124 is the same as or deeper than the height H of the head 121a of the FDS 121. In other words, the close contact portions (the second double wall portion 104 and the third double wall portion 105) of the frame part 101 shown in Figure 43 have the recessed portion 124, and the joining means (in this case, the FDS 121) used for joining do not protrude. This also applies when a blind rivet 33 is used.

[0085] The frame components 8, 101 having a recessed portion 124 at the location where the temporary joining process is performed can be manufactured, for example, using the manufacturing method shown in the flowcharts of Figures 45 and 46. Although not shown, as shown in the flowchart of Figure 25, the frame components 8, 101 using the recessed portion 124 can also be manufactured even if the cutting process S1 is performed after the temporary joining process S3. That is, before or during the forming process S2, the recessed shape forming process S8 is performed to form the recessed portion 124 at the location where the temporary joining process is performed on the plate material 5, and then the temporary joining process is performed on the recessed portion 124 in the temporary joining process S3. If the recessed shape forming process S8 is performed before the forming process S2, a cutting device 4 or a pilot hole press 63 is used, which is installed upstream in the feed direction of the frame components 8, 101 from the multi-stage roll forming machine 6 that performs the forming process S2. In this case, the recessed portion 124 is formed as a recess with an opening shape, for example, a circular recess. When the concave shape forming step S8 is performed during the forming step S2, a multi-stage roll forming machine 6, 64 is used. In this case, the concave shape portion 124 is formed in the shape of a groove extending in the longitudinal direction of the frame component 8, 101.

[0086] By providing a recessed shape consisting of the recessed portion 124 at the position where the temporary joining process will be performed, the recessed shape serves as a marker when determining the position for temporary joining. Furthermore, by making the recessed portion 124 the same height as or recessed lower than the head height H of the temporary joining means, the temporary joining means does not protrude. This prevents the head of the temporary joining means from interfering with a mating part used adjacent to the frame part 8, 101 when joining the frame part 8, 101, and also results in a superior appearance. The head of the temporary joining means here refers to the head 121a in the case of the FDS 121 and the flange 35a in the case of the blind rivet 33. The frame part 8, 101 with this recessed portion 124 does not interfere with the mating part when joined, and results in a frame part with excellent appearance quality.

[0087] When the head of the temporary joining means is accommodated in the recessed portion 124, laser welding may be performed from above the temporary joining means, as shown in Figures 47 and 48. Figure 48 is a cross-sectional view of the frame component 101 shown in Figure 47 cut along an imaginary plane C. The imaginary plane C shown in Figure 47 is hatched downward to the left. By performing laser welding across the recessed portion 124, the head of the temporary joining means (the head 121a of the FDS 121 in Figure 48) and the plate material 5 melt and mix together, creating a weld 125, as shown in Figure 48. By performing laser welding from above the temporary joining means such as the blind rivet 33 or the FDS 121 in this way, the recessed portion 124 serves as a marker for the position where the laser welding will be performed, and the laser welding can be performed at the position where the two plate materials 5 are most closely contacted, thereby increasing the reliability of the welding.

[0088] (Seventh Embodiment with a Different Frame Component Shape) In the above-described embodiments, examples have been shown in which frame components 8, 101 having first to third closed cross-sectional portions 13-15 are formed by roll forming. However, the present invention is also applicable to the case of forming a frame component 134 having a long hollow body 133 in which first and second closed cross-sectional portions 131, 132 are arranged in succession, as shown in Figures 49 and 50 . That is, the manufacturing method according to the present invention is a manufacturing method for forming a frame component having a long hollow body in which at least two closed cross-sectional portions are arranged in succession. In Figures 49 and 50 , components that are the same or equivalent to those described in Figures 1 to 48 are designated by the same reference numerals, and detailed descriptions are omitted as appropriate. In Figures 49 and 50 , solid white arrows indicate positions where the main joining process is performed, and dashed white arrows indicate positions where additional main joining process can be performed. Furthermore, dashed triangles indicate positions where the temporary joining process is performed.

[0089] In the frame part 101 shown in FIG. 49 , after the first horizontal wall 21, the first vertical wall 22, and the second horizontal wall 23 are formed, the plate material 5 is bent upward to form a fifth vertical wall 135 so as to overlap one end 102 of the plate material 5. Then, a fifth horizontal wall 136 is formed parallel to the first horizontal wall 21, and then a sixth vertical wall 137 extending downward is formed. The lower end of the sixth vertical wall 137 becomes the other end 108 of the plate material 5. This sixth vertical wall 137 is formed so as to overlap the first vertical wall 22. The lower end of the sixth vertical wall 137 becomes the other end 106 of the plate material 5. In this frame part 134, the other end 106 is located outside the closed cross section, and the sixth vertical wall 137 is connected to the fifth horizontal wall 136 at a single bending point 107, so warping due to springback is likely to occur. That is, the sixth vertical wall 137 is likely to separate from the first vertical wall 22 due to springback, as shown by the two-dot chain line in Fig. 49. For this reason, in the frame part 134 shown in Fig. 49, a temporary joining process is performed in the temporary joining step S3 on the fourth double wall portion 138 where the sixth vertical wall 137 and the first vertical wall 22 overlap.

[0090] 49 , of the first double wall portion 103 including one end portion 102 and the fourth double wall portion 138 including the other end portion 106, at least the first double wall portion 103 is subjected to the main joining process in the main joining step S5. That is, the fourth double wall portion 138 can be additionally subjected to the main joining process.

[0091] The frame part 134 shown in Figure 50 is formed so that one end 102 extends downward relative to the first horizontal wall 21 in the figure and overlaps with the second vertical wall 24, and the third vertical wall 26 forms the other end 106. In this frame part 134, both the one end 102 and the other end 106 are located outside the closed cross section. The one end 102 and the other end 106 are each connected to the other wall at a single bending point 107. Therefore, in the frame part 134 shown in Figure 50, a fifth double wall portion 139 where the one end 102 overlaps the second vertical wall 24 and a sixth double wall portion 140 where the other end 106 overlaps the first vertical wall 22 are subjected to temporary joining processing in the temporary joining step S3. In addition, in the frame part 134 shown in Figure 50, the main joining process is performed on at least one of the double wall portions, namely, the fifth double wall portion 139 including one end portion 102 and the sixth double wall portion 140 including the other end portion 106, in the main joining step S5.

[0092] Even when forming a frame component 134 having only first and second closed cross-sectional portions 131, 132 as shown in Figures 49 and 50, similar to the embodiment shown in Figures 1 to 48, it is possible to manufacture highly rigid frame components having multiple closed cross-sectional portions with good productivity, and it is also possible to provide frame components formed by roll forming and a manufacturing method thereof that can suppress springback using a simple method to increase welding accuracy.

[0093] In the above-described embodiment, an example in which laser welding is performed in the main welding step S5 has been shown, but the main welding step can also be performed by MIG welding, friction stir welding, or the like, in addition to laser welding.

[0094] The temporary joining process performed in the temporary joining step S3 can be performed using the blind rivets 33, clamps 71, 72, FDS 121, etc. as described above, or, although not shown, can also be performed using an adhesive or brazing. The temporary joining process performed in the temporary joining step S3 is not limited to the above temporary joining means and can be changed as appropriate, as long as it can maintain at least one pair of overlapping plate materials 5 in a mechanically or chemically intimate state to such an extent that the shapes of the closed cross-sectional portions (first to third closed cross-sectional portions 13-15, first closed cross-sectional portion 131, second closed cross-sectional portion 132) of the frame components 8, 101 are maintained.

[0095] (Additional Note) The manufacturing method of the frame component formed by roll forming according to each of the above-described embodiments and the characteristics of the frame component formed by roll forming can be described in the form of claims as follows.

[0096] (Feature 1) The method comprises: a cutting step of cutting a metal plate material to a predetermined length; a forming step of forming a frame part having a long hollow body with at least two closed cross-sectional portions lined up continuously by applying roll forming to the plate material so as to surround one end of the plate material; a temporary joining step of performing a temporary joining process on the frame parts to maintain the shape of the closed cross-sectional portions; a waiting step of making the frame parts wait after the temporary joining process; and a final joining step of welding the frame parts waiting in the waiting step, wherein the temporary joining process performed in the temporary joining step is a joining process that maintains at least one of the overlapping plate materials in a state of mechanical or chemical intimate contact to such an extent that the shape of the closed cross-sectional portions of the frame parts is maintained, and in the final joining step, one end portion formed in an early stage of roll forming of the plate material or the other end portion formed in a final stage is continuously welded to the plate material at the closed cross-sectional portion along the longitudinal direction of the long hollow body, A method for manufacturing a frame component formed by roll forming, characterized in that while the frame component is being formed in the forming process, the welding in the main joining process is performed on another frame component in the waiting process.

[0097] (Feature 2) In the method for manufacturing a frame component formed by roll forming described in Feature 1, the temporary joining process is performed on the one end or the other end located outside the closed cross section while maintaining at least the shape of the hollow portion of the frame component.

[0098] (Feature 3) In the method for manufacturing a frame part formed by roll forming described in Feature 1, the forming process is carried out by performing roll forming so as to surround the one end of the plate material, thereby forming a T-joint with a T-shaped cross section where one end that is the tip of the one end is abutted, and the one end is shared by two of the closed cross-sectional parts to form the boundary between these closed cross-sectional parts, and the T-joint is sandwiched between the two closed cross-sectional parts, and the welding in the main joining process is performed at the T-joint.

[0099] (Feature 4) In the method for manufacturing a frame part formed by roll forming according to Feature 3, the frame part has a ladle-shaped portion formed in a ladle-like cross section with one end located at the open end of the ladle, and an outer frame portion formed in a cup-like cross section that accommodates the ladle and forms the two closed cross-sectional portions that sandwich the T-shaped joint in cooperation with the ladle, and the temporary joining step is performed by performing the temporary joining process on at least a portion where the outer frame portion overlaps the bottom of the ladle and a portion where the outer frame portion overlaps the handle of the ladle.

[0100] (Feature 5) The method for manufacturing a frame component formed by roll forming according to Feature 1, further characterized in that a drilling step is carried out before the forming step to drill rivet holes in the plate material at positions where the temporary joining process will be performed, and the temporary joining step is carried out by driving rivets into the rivet holes using a rivet driving device installed downstream in the feed direction of the frame component from the roll forming device that carries out the forming step.

[0101] (Feature 6) In the method for manufacturing a frame component formed by roll forming described in Feature 1, the temporary joining step is performed by driving a flow drill screw using a flow drill screw driving device installed downstream in the feed direction of the frame component from the roll forming device that performs the forming step.

[0102] (Feature 7) The method for manufacturing a frame component formed by roll forming according to Feature 5 or Feature 6, further characterized in that a concave shape forming step is carried out before or during the forming step, in which a concave portion is formed in the plate material at a position where the temporary joining process is to be performed, and the temporary joining process in the temporary joining step is performed on the concave portion.

[0103] (Feature 8) In the method for manufacturing a frame component formed by roll forming described in Feature 7, the depth of the recess formed in the recess shape forming process is the same as or deeper than the height of the head of the temporary joining means that performs the temporary joining process.

[0104] (Feature 9) In the method for manufacturing a frame component formed by roll forming according to Feature 5 or Feature 6, the roll forming in the forming step applies a forming stress to the frame component so that the frame component is compressively deformed, and the temporary joining process in the temporary joining step is performed when the frame component has restored to its normal shape by springback caused by the forming stress.

[0105] (Feature 10) In the method for manufacturing a frame part formed by roll forming described in Feature 3, a groove forming process is carried out to form a groove in the plate material into which the one end fits, before roll forming is performed on the plate material in the forming process, and in the forming process, the one end fits into the groove, thereby forming the T-shaped joint into its final shape.

[0106] (Feature 11) In the method for manufacturing a frame part formed by roll forming described in Feature 3, a step forming process is carried out to form a step in the plate material so that a part of the plate material is positioned offset to one side in the thickness direction before roll forming is performed on the plate material in the forming process, and in the forming process, the one end engages with the step, thereby forming the T-shaped joint into a final shape.

[0107] (Feature 12) In the method for manufacturing a frame component formed by roll forming according to Feature 10 or Feature 11, the temporary joining process in the temporary joining step is performed in a state where the T-shaped joint portion has been formed into the final shape.

[0108] (Feature 13) In the method for manufacturing a frame component formed by roll forming described in Feature 1, the main joining step is performed by laser welding the one end and another portion of the plate material that contacts the one end from the outside of the frame component.

[0109] (Feature 14) In the method for manufacturing a frame component formed by roll forming according to Feature 13, the laser welding is also performed on a portion that has been subjected to the temporary joining process in the temporary joining step and on a position that is adjacent in the longitudinal direction of the frame component.

[0110] (Feature 15) In the method for manufacturing a frame component formed by roll forming described in Feature 1, the cutting step is performed before the forming step is performed, and the temporary joining process performed in the temporary joining step is performed by clamping the overlapping portions of the plate materials at both longitudinal ends of the frame component with clamps.

[0111] (Feature 16) In the method for manufacturing a frame part formed by roll forming described in Feature 1, the temporary joining process is performed by clamping and binding one outer end and the other outer end of the frame part with a clamping member so that the other end of the plate material is sandwiched between them.

[0112] (Feature 17) A frame component having a long hollow body in which at least two closed cross-sectional portions are lined up in succession by applying roll forming to a plate material, characterized in that the frame component has a tight contact portion where at least one of the overlapping plate materials has been joined to keep them in a mechanically or chemically tight contact state so that the shape of the closed cross-sectional portion is maintained in the frame component, and a weld portion that is continuously welded to the closed cross-sectional portion along the longitudinal direction of the long hollow body at one end formed in the early stage of roll forming of the plate material or the other end formed in the final stage.

[0113] (Feature 18) In the frame component formed by roll forming according to Feature 17, the tightly contacting portion is formed in a tightly contacting state by any one of rivets, flow drill screws, adhesive, and clamps.

[0114] (Feature 19) In the frame component formed by roll forming according to Feature 18, the close contact portion has a concave portion, and the joining means for performing the joining process does not protrude.

[0115] 5...plate material, 8, 83, 101, 134...frame parts, 8A, 101A, 133...hollow body, 9...rivet driving device, 102...one end, 106...other end, 11...one end, 12...T-shaped joint portion, 13...first closed cross-sectional portion, 14...second closed cross-sectional portion, 15...third closed cross-sectional portion, 16...ladle-shaped portion, 17...peripheral frame, 18...outer frame portion, 31...first overlapping portion, 32...second overlapping portion, 33...blind rivet, 34...rivet hole, 37... Groove, 46...step portion, 71...clamp, 72...clamp (pressure member), 103...first double wall portion, 104...second double wall portion, 105...third double wall portion, 106...other end portion, 108...other end portion, 121...flow drill screw, 123...flow drill screw driving device, 124...concave portion, S1...cutting process, S1A, drilling process, S2...molding process, S3...temporary joining process, S4...waiting process, S5...actual joining process, S8...concave shape forming process.

Claims

1. A cutting step of cutting a metal plate material into a predetermined length, a forming step of forming a frame component having a long hollow body in which at least two closed cross-sectional portions are arranged continuously by performing roll forming on the plate material so as to surround one end of the plate material, a temporary joining step of performing a temporary joining process on the frame component in which the shape of the closed cross-sectional portion is maintained, a standby step of waiting for the frame component after the temporary joining process is completed, and a main joining step of welding the frame component waiting in the standby step, wherein the temporary joining process performed in the temporary joining step is a joining process of holding at least one of the plate materials overlapping each other in a mechanically or chemically close state to such an extent that the shape of the closed cross-sectional portion of the frame component is maintained, in the main joining step, one end formed in the initial stage of roll forming of the plate material or the other end formed in the final stage of roll forming is continuously welded to the plate material of the closed cross-sectional portion along the longitudinal direction of the long hollow body, and when the frame component is being formed in the forming step, the welding in the main joining step is performed on the other frame component in the standby step. A method for manufacturing a frame component formed by roll forming, characterized in that.

2. In the method for manufacturing a frame component formed by roll forming according to claim 1, the temporary joining process is performed on at least one of the one end or the other end located outside the closed cross-section while the hollow portion shape of the frame component is maintained. A method for manufacturing a frame component formed by roll forming, characterized in that.

3. In the method for manufacturing a frame component formed by roll forming according to claim 1, in the forming step, by performing roll forming so as to surround the one end of the plate material, a T-shaped joint portion having a T-shaped cross-section in which one end, which is the tip of the one end, abuts is formed, and the one end is shared by the two closed cross-sectional portions and becomes the boundary of these closed cross-sectional portions, and the T-shaped joint portion is sandwiched between the two closed cross-sectional portions, and the welding in the main joining step is performed at the T-shaped joint portion. A method for manufacturing a frame component formed by roll forming, characterized in that.

4. In the method for manufacturing a frame part formed by roll forming according to claim 3, the frame part has a ladle-shaped portion formed in a cross-sectional ladle shape with one end located at the open end of the ladle, and an outer frame portion formed in a cross-sectional cup shape for accommodating the ladle and forming two shut-off portions that cooperate with the ladle to sandwich the T-shaped joint portion, the temporary joining step is carried out by performing the temporary joining treatment at least on a portion where the outer frame portion overlaps the bottom of the ladle and a portion where the outer frame portion overlaps the handle of the ladle. A method for manufacturing a frame part formed by roll forming, characterized by this.

5. In the method for manufacturing a frame part formed by roll forming according to claim 1, further, a punching step of drilling a rivet hole at a position where the temporary joining treatment is performed on the plate material before the forming step is carried out, the temporary joining step is carried out by driving a rivet into the rivet hole using a rivet driving device installed on the downstream side in the feeding direction of the frame part from the roll forming device that performs the forming step. A method for manufacturing a frame part formed by roll forming, characterized by this.

6. In the method for manufacturing a frame part formed by roll forming according to claim 1, the temporary joining step is carried out by driving a flow drill screw using a flow drill screw driving device installed on the downstream side in the feeding direction of the frame part from the roll forming device that performs the forming step. A method for manufacturing a frame part formed by roll forming, characterized by this.

7. In the method for manufacturing a frame part formed by roll forming according to claim 5 or claim 6, further, a concave shape forming step of forming a concave shape portion at a position where the temporary joining treatment is performed on the plate material before or during the forming step is carried out, the temporary joining treatment in the temporary joining step is carried out on the concave shape portion. A method for manufacturing a frame part formed by roll forming, characterized by this.

8. In the method for manufacturing a frame component formed by roll forming according to claim 7, the depth of the recess of the recessed portion formed in the recessed shape forming step is the same as or deeper than the height of the head of the temporary joining means for performing the temporary joining process. A method for manufacturing a frame component formed by roll forming, characterized in that.

9. In the method for manufacturing a frame component formed by roll forming according to claim 5 or claim 6, in the roll forming in the forming step, forming stress is applied so that the frame component is compressed and deformed, and in the temporary joining process in the temporary joining step, the temporary joining process is performed when the frame component is restored to its normal shape due to springback caused by the forming stress. A method for manufacturing a frame component formed by roll forming, characterized in that.

10. In the method for manufacturing a frame component formed by roll forming according to claim 3, before roll forming is performed on the plate material in the forming step, a groove forming step of forming a groove into which one end fits is performed on the plate material, and in the forming step, the T-shaped joint portion is formed into its final shape by fitting one end into the groove. A method for manufacturing a frame component formed by roll forming, characterized in that.

11. In the method for manufacturing a frame component formed by roll forming according to claim 3, before roll forming is performed on the plate material in the forming step, a step forming step of forming a step portion so that a part of the plate material is biased in one direction in the thickness direction is performed, and in the forming step, the T-shaped joint portion is formed into its final shape by engaging one end with the step portion. A method for manufacturing a frame component formed by roll forming, characterized in that.

12. In the method for manufacturing a frame component formed by roll forming according to claim 10 or claim 11, the temporary joining process in the temporary joining step is performed in a state where the T-shaped joint portion is formed into its final shape. A method for manufacturing a frame component formed by roll forming, characterized in that.

13. In the method for manufacturing a frame component formed by roll forming according to claim 1, the main joining step is carried out by laser welding the one end portion and the other portion of the plate material that contacts this one end portion from the outside of the frame component, and is characterized in that it is a method for manufacturing a frame component formed by roll forming.

14. In the method for manufacturing a frame component formed by roll forming according to claim 13, the laser welding is also carried out at a position adjacent to the portion where the temporary joining treatment was carried out in the temporary joining step in the longitudinal direction of the frame component, and is characterized in that it is a method for manufacturing a frame component formed by roll forming.

15. In the method for manufacturing a frame component formed by roll forming according to claim 1, the cutting step is carried out before the forming step is carried out, and the temporary joining treatment carried out in the temporary joining step is carried out by clamping the portions where the plate materials are overlapped at both end portions in the longitudinal direction of the frame component by a clamp, and is characterized in that it is a method for manufacturing a frame component formed by roll forming.

16. In the method for manufacturing a frame component formed by roll forming according to claim 1, the temporary joining treatment carried out in the temporary joining step is carried out by sandwiching and tightening the one outer end portion and the other outer end portion of the frame component with a pressing member so that the other end portion of the plate material is sandwiched therebetween, and is characterized in that it is a method for manufacturing a frame component formed by roll forming.

17. A frame component having a long hollow body in which at least two closed cross-sectional portions are arranged continuously by subjecting a plate material to roll forming, and having a close contact portion where at least one pair of overlapping plate materials are held in a mechanically or chemically close contact state so that the shape of the closed cross-sectional portion is maintained in the frame component, and a welded portion continuously welded to the closed cross-sectional portion along the longitudinal direction of the long hollow body at one end portion formed in the initial stage of the roll forming of the plate material or the other end portion formed in the final stage, and is characterized in that it is a frame component formed by roll forming.

18. In the frame part formed by roll forming according to claim 17, the close contact part is in a close contact state by any one of a rivet, a flow drill screw, an adhesive, and a clamp, and the frame part is formed by roll forming.

19. In the frame part formed by roll forming according to claim 18, the close contact part has a concave shape part, and the joining means for performing the joining process does not protrude, and the frame part is formed by roll forming.

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