Vehicle body side frame manufacturing method and vehicle body side frame

Abstract

[Problem] To provide a vehicle body side frame manufacturing method and a vehicle body side frame with which it is possible to improve productivity, improve performance, and reduce costs through structure rationalization. [Solution] A body side frame is a door ring frame having an integral structure. An annular structure portion and a sill outer structure portion of the door ring frame are individually molded, and the annular structure portion and the sill outer structure portion are joined after molding.

Description

Method for manufacturing a vehicle body side frame and a vehicle body side frame

[0001] The present invention relates to a method for manufacturing a vehicle body side frame and a vehicle body side frame manufactured by the method.

[0002] In many recent vehicles, a monocoque structure is adopted, and various shaped members formed by press working are combined by welding or the like and used for each part of the vehicle body.

[0003] For example, in the press working of the structural frame constituting the side portion of the vehicle, depending on the structure and function required for the side portion of the vehicle, a plurality of blank sheet metals having different thicknesses and materials are combined by welding or the like, and a tailored blank method is used. In many cases, a steel sheet (blank) for pressing is created.

[0004] Regarding such a technique, for example, a technique such as "vehicle body side structural frame" described in Japanese Patent Application Laid-Open No. 2024-28875 (Patent Document 1) is disclosed.

[0005] The technique described in Patent Document 1 is such that the conventional normal vehicle body side structure was constituted by joining a plurality of components (a to f) as shown in, for example, FIG. 1, whereas as shown in FIG. 2(A), a plurality of blank materials (for example, α, β) are spot-welded or laser-welded with welding lines or welding surfaces to form an integral blank material, and then press-formed to obtain a vehicle body side structural frame as shown in FIG. 2(B).

[0006] Furthermore, Patent Document 1 discloses a method comprising "the steps of supplying a plurality of blanks and joining the blanks to each other in order to form a composite blank, wherein the step of joining the blanks includes forming one or more overlapping areas by partially overlapping two blanks, the method further comprising the step of deforming the composite blank in order to form the integrated body side structure frame, wherein the integrated body side structure frame includes a lower beam section, an upper beam section, a front pillar section connecting the lower beam section to the upper beam section, and a rear pillar section connecting the lower beam section to the upper beam section."

[0007] Japanese Patent Publication No. 2024-28875

[0008] (1) However, in the technology described in Patent Document 1, since all four sides of the door ring annular structure have depth, the material flow during press molding is restricted, and molding may be difficult. In other words, in the door ring annular structure of the side of a vehicle body, normally, for example, there is a B pillar with two horizontal flanges in the vertical direction, and below the B pillar there is a side sill section (sill part). In the conventional technology (technology prior to Patent Document 1), in the area shown by the thick circle in Figure 3(A), the flow of material is difficult due to the closed cross section of the sill section. Therefore, as illustrated in Figure 3(B), in the stretch flange shape (stretch FL shape), material introduction from the -Z axis (lower side of the vehicle) cannot be expected, so it is necessary to withstand the stretch in the +Z axis. In other words, as shown in Figure 3(C), because there is a deep groove in the -Z axis, material flow from there cannot be expected. Therefore, as shown in Figure 4(A), there is no degree of freedom in the pressing direction. For example, if the bending angle of the upper K portion of the door ring annular structure is set to 0 degrees as shown in Figure 4(B), then depending on other shape factors, the bending angle of the lower L portion of the door ring annular structure may require a gradient of 10 degrees or more, as shown in Figure 4(C).

[0009] (2) Furthermore, in the case of the technology described in Patent Document 1, the absence of the wall between the B-pillar and the sill, which is present in a normal body side structure, creates a point of bending, resulting in a decrease in rigidity / collision performance of the individual component. That is, in the case of a general body side structure, the Z-plane wall (Z-plane wall) that constitutes the sill, as shown in the circle drawn with the thick line in Figure 5(A) and Figure 5(B), and in Figure 5(C), is located in the direction below the lateral flange of the B-pillar. However, in the case of the technology described in Patent Document 1, the Z-plane wall (Z-plane wall) that constitutes the sill, as shown in the circle drawn with the thick line in Figure 6(A) and Figure 6(B), and in Figure 6(C), does not exist. The same applies to the A-pillar. Therefore, for example, as shown in Figure 7, when considering the load path during a collision, the sill plays a role in protecting the occupant space during a collision, so the absence of the wall between the A-pillar and B-pillar and the sill reduces the rigidity / collision performance of the individual component.

[0010] (3) Furthermore, while the A-pillar and B-pillar utilize an overlapping structure that allows for a reduction in reinforcement, the sill section has less overlap with the pillar, requiring additional reinforcement to be added to the ridges inside the sill. That is, for example, in the case of a body side structure frame as shown in Figure 8 (A1), it is necessary to add reinforcement to the sill section as shown in Figure 8 (B1), and to reinforce it with these separate parts as shown in Figure 8 (C1).

[0011] (4) Furthermore, the sill, A-pillar and B-pillar lower section, etc., as illustrated in Figure 9, are parts that undergo large deformation during a side impact and are required to maintain a certain level of performance without cracking. However, conventional technology uses a hot-stamped integrated structure with poor elongation, raising concerns that it may not satisfy the required performance of not cracking.

[0012] (5) Therefore, the present invention has been made to solve the above-mentioned problems, and aims to provide a method for manufacturing a vehicle body side frame and a vehicle body side frame that, compared to the conventional integrated door ring structure, separates the sill outer part and molds the door ring upper structure and the sill outer structure separately, and then joins them together, thereby enabling increased productivity through structural rationalization, improved performance, and reduced costs.

[0013] To solve the above problems, the present invention provides a method for manufacturing a vehicle body side frame, wherein the body side frame is a door ring frame having an integral structure, and the annular structure portion and the sill outer structure portion of the door ring frame are molded separately, and the annular structure portion and the sill outer structure portion are joined together after molding.

[0014] Furthermore, the above problem can be solved more effectively by including a lower beam portion below the door ring frame in the annular structure portion, and joining the sill outer structure portion to overlap the lower beam portion, or by having the sill outer structure portion have a closed curve in cross-section when viewed from the longitudinal direction, or by having the door ring frame be either a front door ring frame or a rear door ring frame.

[0015] Furthermore, in order to solve the above problems, the present invention provides a vehicle body side frame manufactured by the above manufacturing method.

[0016] In this invention, the annular structure portion and the sill outer structure portion of the door ring frame are molded separately, and the annular structure portion and the sill outer structure portion (sill portion) are joined together after their molding. As a result, the sill portion is not included during the integral molding of the annular structure portion, which is the upper structure, and moldability is improved due to factors such as improved material flowability. Furthermore, the strength is improved by providing the sill portion later with a wrap structure, making it possible to reduce the amount of reinforcement and other components.

[0017] This is a perspective view showing an example of a conventional body side structure in which a front side frame is constructed by joining multiple components. (A) is a plan view showing an example of a composite blank before pressing as described in Patent Document 1, and (B) is a plan view showing an example of a body side structure frame after pressing. This is a diagram showing the material inflow situation during press working using the prior art, where (A) is a plan view showing a door ring annular structure, (B) is a front view illustrating the material inflow path of the elongated flange-shaped portion in (A), and (C) is a cross-sectional view showing the material inflow path on the α-α' line in (A). (Note that in the figures, the direction perpendicular to the plane of the paper is the Y axis. Also, the white dotted line in Figure 3(B) shows the material inflow path in the Z axis direction.) (A) is a front view seen from the direction of the arrow shown in B in Figure 3(A), (B) is an enlarged view of portion K shown in Figure 4(A), and (C) is an enlarged view of portion L shown in Figure 4(A). (A) is a plan view showing a general body side structure, (B) is a perspective view of the part indicated by the thick circle in (A), and (C) is a cross-sectional view of the B pillar between lines I and I' in (A). (A) is a plan view showing the body side structure of Patent Document 1, (B) is a perspective view of the part indicated by the thick circle in (A), and (C) is a cross-sectional view of the B pillar between lines J and J' in (A). This is a perspective view showing an example of a load distribution path (load path) during a frontal collision of a vehicle. Figure (A1) is a perspective view showing a body side structure as shown in Patent Document 1, Figure (A2) is a cross-sectional view of Figure (A1) along the α-α line, Figure (B1) is a perspective view showing an example of a reinforcement, Figure (B2) is a cross-sectional view of Figure (B1) along the β-β line, Figure (C1) is a perspective view showing an example of the body side structure of Figure (A1) being reinforced with the reinforcement of Figure (B1), and Figure (C2) is a cross-sectional view of Figure (C1) along the γ-γ line. This is a perspective view showing a modified body side frame in the event of a collision on the side of the vehicle's body.Figure 10 shows an example of the configuration of a body side frame according to the present invention. (A1) is a perspective view showing the annular structure portion, (B1) is a perspective view showing the sill portion, and (C1) is a perspective view showing an example of overlapping connection between (A1) and (B1). (A2), (B2), and (C2) are perspective views showing similar body side frames and sill portions from different directions, similar to A1, B1, and C1, respectively. Figure 10 shows a partial cross-sectional shape of each figure. (A) is a cross-sectional view of the α'-α' line portion of Figure 10 (A1), (B) is a cross-sectional view of the β'-β' line portion of Figure 10 (B1), and (C) is a cross-sectional view of the γ'-γ' line portion of Figure 10 (C1). (Note that the cross-sections of (A2), (B2), and (C3) in Figure 10 also have basically the same structure.) This is a perspective view showing different configuration examples of the body side frame according to the present invention, where (A) is a perspective view showing the annular structure portion, (B) is a perspective view showing the sill portion with a closed curve structure (rectangle in this case) in cross-section, and (C) is a perspective view showing an example of overlapping connection of (A) and (B). This shows the partial cross-sectional shapes of each figure shown in Figure 12, where (A) is a cross-sectional view of the α"-α" line portion of Figure 12(A), (B) is a cross-sectional view of the β"-β" line portion of Figure 12(B), and (C) is a cross-sectional view of the γ"-γ" line portion of Figure 12(C). This is a diagram showing the material inflow situation during press working according to the present invention, where (A) is a plan view showing the door ring annular structure, (B) is a front view showing the material inflow path of the elongated flange-shaped portion in (A), and (C) is a cross-sectional view showing the material inflow path on the α'-α line of (A). (Note that in the figures, the direction perpendicular to the plane of the paper is defined as the Y-axis. Also, the white dotted line in Figure 14(B) indicates the material inflow path in the Z-axis direction.) (A) is a perspective view showing an example of a conventional door frame annular structure, and (B) is a perspective view showing an example of a door frame annular structure according to the present invention. (A) shows an example of the configuration of the reinforcement and outer part in the door frame annular structure portion according to the prior art, and (B) shows an example of the configuration of the reinforcement and outer part in the door frame annular structure portion according to the present invention.

[0018] The following will provide a more detailed description, with reference to the drawings, of the method for manufacturing a vehicle body side frame according to the present invention and of a vehicle body side frame manufactured by this method.

[0019] The drawings referenced below illustrate the outline of the present invention. Detailed structural elements, proportions, and common structural representations may be simplified or simplified for easier understanding.

[0020] In the present invention, for example, when integrally molding the annular structural portion 100 (or 101) of the door ring frame 500 on the side of the vehicle body shown in Figure 10 (C1 (or C2)) by press molding, as shown in Figure 10 (A1 (or A2)), the lower beam portion 150 (or 151) of the annular structural portion 100 (or 101) is not provided with a sill outer structural portion (sill portion) 300 (or 301), and the lower beam portion 150 (or 151) is configured in a relatively simple shape facing downwards toward the door ring frame.

[0021] Then, the sill portion 300 (or 301), which has been formed in advance, for example as shown in Figure 10 (B1 (or B2)), is joined to the lower beam portion 150 (or 151), and as a result, an integrated structure of the annular structural portion 100 (or 101) and the sill portion 300 (or 301) is obtained, which is completed as a doorring frame 500 (or 501) as shown in Figure 10 (C1 (or C2)).

[0022] Therefore, each of the above-mentioned components constituting the present invention will be described below.

[0023] In this invention, in terms of time, the annular structure portion 100 (or 101) of the door frame 500 is created first (step S1), the sill portion 300 (or 301) is created next (step S2), and finally the annular structure portion 100 (or 101) of the door frame 500 and the sill portion 300 (or 301) are connected (step S3). However, the order of steps 1 and 2 may be reversed.

[0024] First, the annular structural portion 100 (or 101) of the door frame 500 constituting the present invention is mainly composed of an A-pillar 110 (or 111), a B-pillar 130 (or 131), a lower beam portion 150 (or 151), and a hinge pillar portion 170 (or 171), as shown in Figure 10 (A1 (or A2)).

[0025] Of these, the A-pillar 110 (or 101) is a support column located on either side of the windshield when the vehicle is viewed from the front. It is also called the front pillar and is located at the very front of the vehicle, supporting the windshield and connecting the roof to the body. The B-pillar 130 (or 131) is a support column located in the center of the side of the vehicle. It is also called the center pillar and is the support column to which the seat belts of the front seats are attached. In addition, it increases the rigidity of the vehicle's body and contributes to safety in the event of a side collision. The hinge pillar section 170 (or 171) is the part to which the door hinge is attached. It is located as part of the A-pillar or below it, supporting the hinge of the front door and bearing the load when the door is opened and closed.

[0026] Furthermore, the lower beam section 150 (or 151) extends in the longitudinal direction of the vehicle and connects the lower part of the A-pillar 110 (or 101) and the lower part of the B-pillar 130 (or 131).

[0027] Furthermore, in the case of the annular structural portion 100 (or 101) of a typical door frame 500, the lower beam portion 150 (or 151) is often formed together with the sill outer structural portion or a part thereof.

[0028] However, in the present invention, the lower beam portion 150 (or 151) is configured in a relatively simple shape that is directed downward when viewed from the entire annular structure portion 100 (or 101), as shown in the perspective view in Figure 10 (A1 (A2)) or the cross-sectional view in Figure 11 (A), etc., and when press forming is performed to obtain the annular structure portion 100 (or 101), it is configured in a shape that does not include the sill portion.

[0029] This is because, in the present invention, the annular structural portion 100 (or 101) is completed by press molding, and then the sill portion 300 (or 301) is later joined to the lower beam portion 150 (or 151). For the formation of the annular structural portion 100 (or 101), general methods such as the conventional tailored blanking method can be used.

[0030] Therefore, although the structure of the lower beam section 150 (or 151) in this example is inclined in the direction inward or outward of the vehicle, it is not necessarily limited to this and may also consist of curved surfaces, etc., within the scope of the above purpose, taking into consideration, for example, that it does not hinder press forming.

[0031] Next, the sill outer structure portion (sill portion) 300 (or 301) of the door ring frame 500 that constitutes the present invention is a component that is constructed separately from the annular structure portion 100 (or 101) of the door ring frame 500, as shown in Figure 10 (B1 (or B2)).

[0032] Furthermore, the sill portion 300 (or 301) is a structural member located on the lower side of the vehicle, extending in the longitudinal direction of the vehicle, increasing the rigidity of the vehicle body, and contributing to safety during side collisions.

[0033] The sill portion 300 (or 301) according to the present invention has a substantially hat-shaped cross-section, as shown in, for example, the perspective view in Figure 10 (B1 (or B2)) and the longitudinal cross-sectional view in Figure 11 (B), etc. The side plane 310 corresponding to the top of the hat shape is positioned to face the lower beam portion 150 (or 151) of the annular structure portion 100 (or 101). When positioned in this manner, the plane extending from the upper side of the side plane 310 in the outward direction constitutes the upper side surface 330, and the plane extending from the lower side in the outward direction constitutes the lower side surface 350. An upper flange 331 and a lower flange 351 are provided at the ends of each.

[0034] Furthermore, since the sill portion 300 (or 301) according to the present invention is formed separately from the annular structure portion 100 (or 101), it can be manufactured using a different material than the annular structure portion 100 (or 101), and the manufacturing method is not limited to pressing; any various means can be selected.

[0035] Furthermore, since the form of the sill portion 300 (or 301) is not particularly limited, various forms can be adopted within the scope of the present invention. For example, in the annular portion structure 100A of a door as shown in Figure 12(A), the cross-section of the sill portion 300A as viewed from the longitudinal direction can be configured as a closed curve shape including a rectangle, as illustrated in Figure 12(B). In that case, the cross-section can be defined as follows: for example, as shown in Figure 13(B), the face on the side facing the lower beam 150 as shown in Figure 13(A) is the inner plane 310A, and the face opposite to the lower beam 150 is the outer plane 331A. In addition, the upper and lower sides can be defined as the upper side 330A and the lower side 350A, respectively.

[0036] Next, we will describe the joining of, for example, the annular structure portion 100 and the sill outer structure portion 300 obtained as described above.

[0037] In the present invention, as described above, over time, the annular structure portion 100 and the sill outer structure portion 300 are manufactured separately in steps S1 and S2, and in the subsequent step 3, these components are joined together by means such as welding to complete the door ring frame 500.

[0038] Furthermore, there are no particular limitations on the welding method; any method can be used, such as spot welding, arc welding, or laser welding.

[0039] Furthermore, when joining the annular structure portion 100 and the sill outer structure portion 300, it is possible to join them by overlapping (overlapping) parts of the lower beam portion 150 and the sill portion 300, for example, as illustrated in Figure 11(C) or Figure 13(C).

[0040] In that case, if we define the overlap ratio Or, which is the ratio of the overlapping portion, as Or = d / W (where d is the length of the overlapping portion and W is the length of the portion of the sill facing the lower beam), then the overlap ratio Or does not have to be uniform along the longitudinal direction of the sill.

[0041] Therefore, in the present invention, for example, by changing the width and shape of the lower beam portion and sill portion in the overlap portion, it is possible to increase the overlap rate Or in the portion of the sill portion 300 corresponding to the lower part of the annular structure portion 100 below the B pillar to improve strength.

[0042] According to the "Method for Manufacturing a Vehicle Body Side Frame and Vehicle Body Side Frame" of the present invention, with the above configuration, by not including a sill shape during the integral molding of the upper part, one side of the annular structure constituting the door frame becomes a simple cross-section without depth, thereby improving the fluidity of the material. Furthermore, since one side is open in terms of the pressing direction, it is possible to set the pressing direction considering moldability and improve moldability.

[0043] That is, in the present invention, as shown in FIG. 14(A), since the lower beam portion of the annular structure portion does not include a sill portion, as shown in FIG. 14(B), in the extended flange shape (extended FL shape), it is possible to prevent the occurrence of cracks by assisting the extension in the +Z axis direction due to the inflow of material from the -Z axis. In other words, as shown in FIG. 14(C), since there is no vertical wall on the -Z axis side, the inflow of material from the -Z axis side can be expected. Therefore, as shown in FIG. 15(A), in the case of the conventional structure, since the lower side (-Z side) of the door frame is in a bag shape as shown by the dotted frame in the figure, the pressing direction is limited. However, in the case of the present invention, as shown by the dotted frame in FIG. 15(B), it is in an open shape, the degree of freedom of the pressing direction is expanded, and the pressing direction can be greatly inclined, so it is possible to facilitate the formability. Therefore, for example, as described above with respect to FIG. 4, even when the gradient of the upper side of the door frame is set to 0 degrees, according to the manufacturing method of the present invention or the structure using the same, since the sill portion can be formed separately, it is possible to adopt a structure in which it is not necessary to set a gradient of 10 degrees or more on the lower side.

[0044] Moreover, according to the present invention, since the upper ridge line portion of the sill structure remains, the strength of the ridge line portion, which has been reduced in the prior art, is maintained. And due to the lap structure between the lower part of the door ring and the upper part of the sill structure, the strength of the ridge line portion is improved, and it is possible to reduce the rain reinforcement inside the sill.

[0045] That is, in the present invention, as shown in FIGS. 11(C) and 13(C) described above, since the upper ridge line portion of the sill structure portion overlaps with the lower beam portion of the door ring frame, it is possible to prevent the strength reduction of both line portions.

[0046] Furthermore, in this invention, as a result of maintaining and improving the strength of the ridge section, for example, conventionally, the door ring frame, which was composed of 9 conventional reinforcement parts (k to s) as shown in the left diagram of Figure 16(A) and 6 outer parts (a to f) as shown in the right diagram of Figure 16(A), can be modified to 8 reinforcement parts (k to m, o to s) by reducing the reinforcement (nRf) of the sill portion, as shown in the left diagram of Figure 16(B). In addition, as shown in the right diagram of Figure 16(B), it is possible to reduce the conventional 4 parts to 2 outer parts (100, 300) and create an integrated door ring structure with the sill portion as a separate part. The above-mentioned outer parts 6 (A to F) include, for example, the following parts (A: RAIL ROOF SIDE OTR, B: BRACE CTR PLR HINGE, C: REINF SILL OTR, D: BRACE SILL OTR FR, E: BRACE FR PLR LWR HINGE, F: REINF FR PLR OTR). Furthermore, in this invention, since the annular structure portion and the sill portion of the door frame are separated, it is possible to use a different material for the sill portion than for the annular structure portion of the door frame, thereby improving customizability.

[0047] In other words, in this invention, while the annular structural portion of the door frame is made of steel, it is possible to apply materials such as an aluminum extruded member for collision energy absorption to the sill portion.

[0048] Therefore, according to the present invention, it is possible to provide a method for manufacturing a vehicle body side frame and a vehicle body side frame capable of improving productivity, performance, and cost reduction through structural rationalization. Note that the configuration example of the present invention described above shows an example of the configuration of the present invention, and within the scope of the gist of the present invention, each component can be arbitrarily replaced or changed. Therefore, in the above-described configuration example, the example of the front side door frame has been mainly described, but it is not limited thereto, and it may be directed to the rear side door frame or the entire rear side frame. Explanation of Symbols

[0049] 100, 100A, 101: Annular structure part 110: A pillar 130: B pillar 150, 151: Lower beam part 170, 171: Hinge pillar 300, 300A, 301: Sill outer structure part 310: Side plane 310A: Inner side plane 311A: Outer side plane 330, 330A: Upper side surface 331: Upper flange 350, 350A: Lower side surface 351: Lower flange 500, 500A: Door ring frame d: Length of overlap part W: Length of part of sill facing lower beam part Or: Overlap ratio

Claims

1. A method for manufacturing a vehicle body side frame, wherein the body side frame is a door ring frame having an integral structure, and the annular structure portion and the sill outer structure portion of the door ring frame are molded separately, and the annular structure portion and the sill outer structure portion are joined together after molding.

2. The method for manufacturing a vehicle body side frame according to claim 1, wherein the annular structure portion includes a lower beam portion below the door ring frame, and the sill outer structure portion overlaps and is joined to the lower beam portion.

3. The method for manufacturing a vehicle body side frame according to claim 2, wherein the sill outer structure portion has a cross-section that forms a closed curve when viewed from the longitudinal direction.

4. The method for manufacturing a vehicle body side frame according to claim 2, wherein the door ring frame is a front door ring frame or a rear door ring frame.

5. A vehicle body side frame manufactured by the manufacturing method described in claims 1 to 4.

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