Vehicle lower body structure

Abstract

To enable welding of a reinforcement member to a closed cross-sectional structure formed of a lower cross member and an upper cross member without providing an opening through which a welding gun passes.SOLUTION: A reinforcement member 19 is placed at a closed cross-sectional structure formed by welding a lower cross member and an upper cross member. The reinforcement member 19 includes a front surface portion, an upper surface portion, a pair of side surface portions 193 and 194, and further includes first flanges 193a and 194a, and second flanges 193b and 194b continuous to the pair of respective side surface portions 193 and 194. The first flanges 193a and 194a are welded to the vertical wall portion of the lower cross member, and the second flanges 193b and 194b are welded to the lower surface portion of the lower cross member. Thereby, prior to the welding process of the lower cross member and the upper cross member, the rigid reinforcement member 19 can be welded to the lower cross member.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to an automobile body structure, and more particularly to a body structure in which a reinforcing member is joined to a body structural member that forms a closed cross-sectional structure. [Background technology]

[0002] Closed cross-section structures have higher strength and rigidity than open cross-section structures and are widely used in vehicle body components. Patent Document 1 discloses a vehicle body structure in which a reinforcing member is joined to a vehicle body component that forms a closed cross-section structure. In this vehicle body structure, in order to further increase the strength and rigidity of the closed cross-section structure, the reinforcing member is joined to the vehicle body component via a flange portion formed integrally with the reinforcing member. Specifically, the reinforcing member is joined to a hat-shaped cross-section member that forms the closed cross-section structure together with a flat plate-shaped member that extends in the vehicle width direction and opens upward.

[0003] The reinforcing member of Patent Document 1 has left and right side portions and an upper surface portion connecting them, and has a total of eight flange portions extending from the front and rear edges of the upper surface portion, the front and rear edges of both side portions, and the lower edges of both side portions. A total of three flange portions extending from the upper surface portion and the front edges of both side portions of the reinforcing member are joined to the front surface portion of the hat-shaped cross-section member, a total of three flange portions extending from the upper surface portion and the rear edges of both side portions of the reinforcing member are joined to the rear surface portion, and a total of two flange portions extending from the lower edges of both side portions of the reinforcing member are joined to the bottom surface portion. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2014-162400 A Summary of the Invention [Problem to be solved by the invention]

[0005] In the structure described in Patent Document 1, the reinforcing members are joined to three surfaces (front, rear, and bottom) of the hat-shaped cross-section member, thereby further increasing the strength and rigidity of the closed cross-section structure formed by the hat-shaped cross-section member and the flat plate-shaped member. When this structure is applied to a closed cross-section structure formed by the reinforcing members and the hat-shaped cross-section member, there is no problem because the reinforcing members can be welded to the three surfaces of the hat-shaped cross-section member before the closed cross-section structure is formed. However, problems arise when applying this structure to other closed cross-section structures typically found in the rear of a passenger compartment of a passenger vehicle. Specifically, the structure may include a vehicle body structure having a cross-member lower extending in the vehicle width direction and in the vehicle up-down direction, a lower surface portion connected to the lower edge of the vertical wall portion and positioned forward, and an upper surface portion connected to the upper edge of the vertical wall portion and positioned rearward, the cross-member upper including a front surface portion located forward of the vertical wall portion of the cross-member lower and an upper surface portion connected to the upper edge of the front surface portion and positioned rearward, the cross-member upper forming a closed cross-section structure together with the cross-member lower. If the structure of Patent Document 1 were to be applied to this vehicle body structure, it would be necessary to weld reinforcing members to two surfaces of the lower cross member, then weld the upper cross member to the lower cross member, and finally weld a reinforcing member to one surface of the upper cross member inside the closed cross section structure. This would require providing an opening in the lower cross member or upper cross member to pass a welding gun through for welding work on the closed cross section structure, which would be extremely disadvantageous in terms of strength and rigidity.

[0006] Therefore, problems remain to be solved when applying the reinforcing member of Patent Document 1 to a vehicle body structure in which the above-mentioned cross member lower and cross member upper form a closed cross section structure. [Means for solving the problem]

[0007] In view of the above-mentioned problems, the present inventors have earnestly studied ways to improve the strength and rigidity of a vehicle body structure in which a closed cross-section structure is formed by the above-mentioned cross-member lower and cross-member upper by arranging a reinforcing member inside the closed cross-section structure while ensuring productivity. First, in order to improve productivity, they considered reducing the joint surface between the reinforcing member and the member that forms the closed cross-section structure. However, reducing the joint surface reduces the reinforcing effect of the reinforcing member. Therefore, they considered increasing the strength and rigidity of the reinforcing member itself. As a result, they arrived at the idea of ​​compensating for the reduced reinforcing effect by providing the reinforcing member with an upper surface portion, a front surface portion, and a side surface portion that are continuous with each other, thereby increasing the strength and rigidity of the reinforcing member itself.

[0008] The present invention, which embodies this concept, is premised on a vehicle body structure having a cross-member upper that includes vertical wall portions extending in the vehicle width direction and the vehicle up-down direction, a lower surface portion that is continuous with the lower edge of the vertical wall portion and located forward, and an upper surface portion that is continuous with the upper edge of the vertical wall portion and located rearward, a cross-member lower that extends in the vehicle width direction, a front portion that is located forward of the vertical wall portion of the cross-member lower, and an upper surface portion that is continuous with the upper edge of the front portion and located rearward, and that forms a closed cross-sectional structure together with the cross-member lower. The present invention includes a reinforcing member that is arranged inside the closed cross-sectional structure formed by the cross-member lower and the cross-member upper. This reinforcing member has a front portion that faces the front of the vehicle, an upper surface portion that is continuous with the upper edge of the front portion, and a side surface portion that is continuous with the side surface portion of the front portion. Around The cross member has a pair of continuous side surfaces, a pair of first flanges continuous with the rear edges of the pair of side surfaces, and a pair of second flanges continuous with the lower edges of the pair of side surfaces. The pair of first flanges are joined to the vertical wall portions of the cross member lower, and the pair of second flanges are joined to the lower surface portions of the cross member lower. Furthermore, a damping member is filled in at least a part of the gap between the upper surface of the cross member upper and the upper surface of the reinforcing member. do.

[0009] According to this configuration, the pair of side surfaces of the reinforcing member To the departmentThe first flange, which is integrally formed, is joined to the vertical wall of the cross-member lower, and the second flange, which is also integrally formed on the side, is joined to the lower surface of the cross-member lower. This provides sufficient reinforcement for the closed cross-section structure of the reinforcing member. On the other hand, before welding the cross-member lower and the cross-member upper together, the cross-member lower and the reinforcing member and This allows welding and increases productivity.

[0011] In addition, a damping member is filled in at least a part of the gap between the upper surface of the cross member upper and the upper surface of the reinforcing member. By doing so, the joint between the vertical wall of the lower cross member and the flange on the lower surface of the cross member upper above The addition of the side sections means that the reinforcing member is essentially joined on three sides, further enhancing the reinforcing effect on the closed cross-section structure of the reinforcing member.

[0012] In the present invention, The damping member is made up of a plurality of members, each of which is spaced apart from one another in the vehicle width direction and is attached to the upper cross member. above The adhesive may be filled in the gap between the face portion and the upper surface of the reinforcing member.

[0013] According to this configuration, the damping members are arranged at a plurality of locations spaced apart on the upper surface, and thus the damping members are effectively used to transmit load, further enhancing the reinforcing effect of the reinforcing member on the closed cross-sectional structure.

[0014] In the present invention, the shape of the reinforcing member may be plane-symmetrical with respect to a vertical plane extending in the vehicle up-down direction.

[0015] According to this configuration, the symmetrical reinforcing members absorb the loads input from all directions to the closed cross-sectional structure without bias, further enhancing the reinforcing effect on the closed cross-sectional structure.

[0016] Furthermore, the plane of symmetry of the reinforcing member may be positioned at the center in the vehicle width direction.

[0017] According to this configuration, the reinforcing member located at the center in the vehicle width direction absorbs the load input to the closed cross-sectional structure from all directions evenly, further enhancing the reinforcing effect on the closed cross-sectional structure.

[0018] In the present invention, the lower surface of the cross member lower may have a raised portion that rises higher than other portions, and the second flange portion of the reinforcing member may be joined to the raised portion.

[0019] According to this configuration, the cross-sectional area of ​​the closed cross-sectional structure formed by the cross member lower and cross member upper is smallest and the reinforcing member is joined to the raised portion where deformation is most likely to occur, thereby making effective use of the reinforcing member. [Effects of the Invention]

[0020] As described above, according to the vehicle body structure of the present invention, it is possible to weld a reinforcing member that has a sufficient reinforcing effect on the closed cross-section structure to the cross-member lower, and then weld the cross-member lower and cross-member upper together to complete the closed cross-section structure, thereby improving productivity. [Brief explanation of the drawings]

[0021] [Figure 1] 1 is a plan view of a lower body of an automobile equipped with a vehicle body structure according to an embodiment of the present invention. [Figure 2] FIG. 2 is an exploded perspective view showing the periphery of a third cross member of the vehicle lower body. [Figure 3] FIG. 4 is a perspective view of the third cross member as seen obliquely from the front. [Figure 4] FIG. 4 is a cross-sectional view taken along the line AA in FIG. 3. [Figure 5] FIG. 4 is a cross-sectional view taken along the line BB in FIG. 3. [Figure 6] FIG. 10 is a perspective view of the gusset as seen obliquely from the front. [Figure 7] FIG. 7 is a cross-sectional view taken along the line CC in FIG. 6. DETAILED DESCRIPTION OF THE INVENTION

[0022] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. In the accompanying drawings, Fr and Rr respectively indicate the front (or forward) and rear (or rear) sides of the automobile, and OUT and IN respectively indicate the outside (or outward) and inside (or inward) sides in the width direction of the automobile.

[0023] 1 shows an automobile lower body 1 equipped with a vehicle body structure according to an embodiment of the present invention. The lower body 1 includes a pair of left and right side sills 2 extending in the longitudinal direction of the vehicle, a tunnel panel 3 disposed in the center of the vehicle width direction between the pair of left and right side sills 2 and extending in the longitudinal direction of the vehicle, and a right floor panel 41 and a left floor panel 42 extending inward in the vehicle width direction from the inner ends of the pair of left and right side sills 2 in the longitudinal direction to the tunnel panel 3.

[0024] A pair of left and right floor frames 5 are arranged as reinforcing members in the lower body 1, extending in the longitudinal direction of the vehicle between a pair of left and right side sills 2 and a tunnel panel 3. A first cross member 6 and a second cross member 7 are arranged in this order toward the rear of the vehicle, spanning the width of the vehicle between the pair of left and right side sills 2 and the tunnel panel 3.

[0025] Further, disposed in front of the first cross member 6 is a diagonal frame 8 that extends diagonally rearward from the pair of left and right side sills 2 to the pair of left and right floor frames 5. Further, behind the second cross member 7, a third cross member 9 is suspended between the pair of left and right side sills 2.

[0026] Meanwhile, the front portion of the lower vehicle body 1 is equipped with a dash panel 10a, a dash panel cowl 10b, a pair of left and right front side frames 11, a bumper reinforcement 12, a front cross member 13, an apron member 14, a suspension housing 15, etc. The rear portion of the lower vehicle body 1 is equipped with a pair of left and right rear side frames 16 extending rearward from the rear ends of the pair of left and right side sills 2, a rear floor panel 17 extending in the vehicle width direction between the pair of left and right rear side frames 16, and a rear cross member 18.

[0027] Left and right floor panels 41, 42 extend in the longitudinal direction of the vehicle from dash panel 10a to third cross member 9 in FIG.

[0028] As shown in FIG. 2, the third cross member 9 having a closed cross section structure is formed by joining a cross member lower 91 which is a lower rear member and a cross member upper 92 which is an upper front member.

[0029] The cross member lower 91 has a shape symmetrical in the vehicle width direction and includes a vertical wall portion 911 extending in the vehicle vertical direction, a lower surface portion 912 protruding forward from the lower edge of the vertical wall portion 911, and an upper surface portion 913 protruding rearward from the upper edge of the vertical wall portion 911. The lower surface portion 912 is spot welded to the rear end portions of the floor panel 4 and the tunnel panel 3. The upper surface portion 913 is spot welded to the front end portion of the rear floor panel 17. The central portion of the lower surface portion 912 is higher in the vehicle vertical direction toward the center to match the change in height of the tunnel panel 3, and the vertical length of the vertical wall portion 911 also decreases toward the center. The position of the lower surface portion 912 is highest at the center in the vehicle width direction.

[0030] As shown in Figure 4, which is a cross-sectional view taken along line AA in Figure 3, cross member upper 92 has a shape symmetrical in the vehicle width direction and has a front surface portion 921 extending in the vehicle vertical direction, a lower surface portion 922 protruding forward from the lower edge of front surface portion 921, and an upper surface portion 923 protruding rearward from the upper edge of front surface portion 921. Lower surface portion 922 is spot-welded to the rear ends of floor panel 4 and tunnel panel 3. Upper surface portion 923 is spot-welded to the front end of rear floor panel 17.

[0031] The cross member lower 91 and the cross member upper 92 are welded together at the lower surface 912 of the cross member lower to the lower surface 922 of the cross member upper, and at the upper surface 913 of the cross member lower to the upper surface 923 of the cross member upper, respectively, to form a closed cross section structure.

[0032] As shown in Figure 2, a gusset 19 is disposed inside the closed cross-section structure formed by the cross member lower 91 and the cross member upper 92 as a reinforcing member for the third cross member 9. The gusset extends in the up-down and front-to-rear directions of the vehicle and has a symmetrical shape with a vertical plane located in the center of the vehicle width direction as the plane of symmetry.

[0033] As shown in FIG. 6, the gusset 19 is composed of a front portion 191 facing the front of the vehicle, an upper surface portion 192 that is continuous with the upper end of the front portion 191, a right side surface portion 193 that is continuous with the right end portion of the front portion 191, and a left side surface portion 194 that is continuous with the left end portion.

[0034] The front surface portion 191 consists of a central front surface portion 191a in which a downwardly opening notch is formed, a right front surface portion 191b that continues from the inclined portion at the right end of the central front surface portion 191a and protrudes further forward than the central front surface portion 191a, and a left front surface portion 191c that continues from the inclined portion at the left end of the central front surface portion 191a and protrudes further forward than the central front surface portion 191a.

[0035] The upper surface portion 192 consists of a central upper surface portion 192a in which an upwardly opening notch is formed, a right upper surface portion 192b that continues from the inclined portion at the right end of the central upper surface portion 192a and protrudes upward beyond the central upper surface portion 192a, and a left upper surface portion 192c that continues from the inclined portion at the left end of the central upper surface portion 192a and protrudes upward beyond the central upper surface portion 192a.

[0036] 7, right side surface portion 193 includes a first flange portion 193a continuing to the rear side and a second flange portion 193b continuing to the lower side. Similar to right side surface portion 193, left side surface portion 194 includes a first flange portion 194a continuing to the rear side and a second flange portion 194b continuing to the lower side. First flange portions 193a, 194a are joined to vertical wall portion 911 of cross member lower 91, and second flange portions 193b, 194b are joined to lower surface portion 912 of cross member lower 91.

[0037] A circular damping member 20 is bonded to the gap between the upper surface portion 192 of the gusset 19 and the upper surface portion 923 of the cross member upper 92. 192bThe first member 20a is 192c The second member 20b is bonded to the

[0038] Here, the damping member 20 is a viscoelastic member having a storage modulus of 500 MPa or less and a loss factor of 0.2 or more under conditions where the temperature is 20°C and the frequency of the excitation force is 30 Hz. The damping member 20 itself has an adhesive effect, and is also called a damping bond because it has a relatively high viscosity before drying. The upper surface portion 192 of the gusset and the upper surface portion 923 of the cross member upper 92 are joined to each other only by the adhesive force of the damping member 20.

[0039] Next, a process for disposing the gusset 19 and the damping member 20 inside the third cross member 9 will be described using the cross member lower 91, cross member upper 92, gusset 19, and damping member 20 shown in FIG. 2. First, the cross member lower 91 and the gusset 19 are welded together. Specifically, the first flange portions 193a and 194a of the gusset 19 are welded to the vertical wall portion 911 of the cross member lower 91, and the second flange portions 193b and 194b are welded to the lower surface portion 912 of the cross member lower 91. Next, the damping member 20 is applied to the upper surface portion 192 of the gusset 19. When applying the damping member 20, it is necessary to apply it thicker than the gap between the upper surface portion 192 of the gusset 19 and the upper surface portion 923 of the cross member upper 92. For example, if the gap is 0.5 to 3.5 mm, it is preferable to apply the damping member 20 to a thickness of 6.0 to 8.0 mm. The solvent in the damping member 20 volatilizes and solidifies when it comes into contact with air, so after application, the lower surface 912 of the cross member lower is welded to the lower surface 922 of the cross member upper, and the upper surface 913 of the cross member lower is welded to the upper surface 923 of the cross member upper. In this way, the gusset 19 is welded to the cross member lower 91 inside the third cross member 9, and is bonded to the cross member upper 92 via the damping member 20.

[0040] As described above, a box-shaped reinforcement structure is first formed by welding the gusset 19 and the cross member lower 91. Next, a closed cross-section structure is formed by welding the cross member lower 91 and the cross member upper 92. This makes it possible to increase the rigidity of the third cross member 9 without providing an opening in the cross member lower 91 or the cross member upper 92 for passing a welding gun through.

[0041] Furthermore, when the cross member lower 91 and the cross member upper 92 are welded together, the damping member 20 is filled into the gap between the cross member upper 92 and the upper surface 192 of the gusset 19. This further increases the rigidity of the third cross member 9. [Explanation of symbols]

[0042] 1...Lower body 2...Side sill 3...Tunnel panel 4...Floor panel 41...Right floor panel 42...Left floor panel 5...Floor frame 6...First cross member 7...Second cross member 8...Diagonal frame 9...Third cross member 91...Cross member lower 911...Vertical wall part 912...Lower side part 913...Upper side part 92...Cross member upper 921...Front section 922...Lower section 923...Upper section 10a...Dash panel 10b...Dash panel cowl 11...Front side frame 12...Bumper reinforcement 13...Front cross member 14... Apron member 15...Suspension housing 16...Rear side frame 17...Rear floor panel 18...Rear cross member 19... Gusset (reinforcement member) 191...Front section 191a...Central front section, 191b...Right front section, 191c...Left front section 192...Top part 192a...Central top part, 192b...Right top part, 192c...Left top part 193...Right side part 193a...first flange portion 193b...second flange portion 194...Left side part 194a...first flange portion 194b...second flange portion 20...Dampening member 20a...first member, 20b...second member

Claims

1. a cross member lower extending in the vehicle width direction, the cross member lower including: a vertical wall portion extending in the vehicle width direction and the vehicle up-down direction; a lower surface portion contiguous with a lower edge of the vertical wall portion and positioned forward; and an upper surface portion contiguous with an upper edge of the vertical wall portion and positioned rearward; a cross member upper including a front surface portion located forward of the vertical wall portion of the cross member lower and an upper surface portion located rearward and continuous with an upper edge of the front surface portion, the cross member upper forming a closed cross section structure together with the cross member lower; A vehicle body structure having a reinforcing member disposed inside a closed cross-sectional structure formed by the cross member lower and the cross member upper, the reinforcing member integrally comprises a front portion facing the front of the vehicle, an upper surface portion continuous with the upper edge of the front portion, a pair of side surfaces continuous with the side edges of the front portion, a pair of first flanges continuous with the rear edges of the pair of side surfaces, and a pair of second flanges continuous with the lower edges of the pair of side surfaces, the pair of first flanges being joined to the vertical wall portions of the cross member lower, and the pair of second flanges being joined to the lower surface portions of the cross member lower, A vehicle body structure, characterized in that at least a part of a gap between the upper surface portion of the cross member upper and the upper surface portion of the reinforcing member is filled with a damping member.

2. 2. The vehicle body structure according to claim 1, wherein the damping member is filled in the gap at a plurality of locations spaced apart from one another in the vehicle width direction.

3. 3. The vehicle body structure according to claim 1, wherein the shape of the reinforcing member is plane-symmetrical with respect to a vertical plane extending in the up-down direction of the vehicle.

4. 4. The vehicle body structure according to claim 3, wherein the plane of symmetry of the reinforcing member is positioned at the center in the vehicle width direction.

5. A vehicle body structure as described in any one of claims 1 to 4, characterized in that the lower surface portion of the cross member lower has a raised portion that rises higher than other portions, and the second flange portion of the reinforcing member is joined to the raised portion.

Images