Lower vehicle body structure of vehicle

Abstract

The purpose of the present invention is to suppress inward deformation of a sheet metal suspension cover during normal travel and to suppress bending deformation of a frame during a rear collision. A hollow frame (3) constituting a closed cross-sectional section (3s) extending in the front-rear direction has a narrow section (37) at a location adjacent to a sheet metal suspension cover (4) provided to the frame (3) and supporting a suspension on the inner side in the vehicle width direction, and the narrow section (37) is narrower than the location adjacent to the suspension cover (4) in the front-rear direction. A closed cross section (3s) of the narrow section (37) in the vehicle width direction is reduced, a cross member (55) extending in the vehicle width direction and disposed at the same front-rear position as the suspension cover (4) is provided on the inner side of the frame (3) in the vehicle width direction, and the narrow section (37) is provided with a joint member (60). The joint member (60) connects the suspension cover (4) and the cross member (55) and is capable of transmitting an input load from the suspension from the suspension cover (4) to the cross member (55).

Description

Technical Field

[0001] The present invention relates to a vehicle lower body structure including a frame constituting a closed cross-section portion extending in the front-rear direction outside a floor panel in the vehicle width direction, and a suspension cover provided on the frame. Background Art

[0002] In a vehicle's lower body structure, ensuring rigidity against loads input from the suspension via the suspension cover supporting the suspension (hereinafter also referred to as the "suspension cover") is crucial for achieving superior handling stability and good ride comfort during normal driving.

[0003] The lower body structure of such a vehicle currently has the following structure: a frame is provided with a closed cross-section portion extending in the front-rear direction on the outside of the floor panel in the vehicle width direction, and a suspension cover is provided on the outside of the frame in the vehicle width direction. However, a structure in which a suspension cover is provided on the frame as in Patent Document 1 has recently been known.

[0004] However, in a structure where the suspension cover is provided on the frame, the cross section of the frame around the suspension cover along the vehicle width direction, that is, the width dimension of the frame is reduced, and there is a concern that the rigidity of the frame itself may be insufficient.

[0005] Furthermore, the suspension cover of Patent Document 1 is made of aluminum die-casting, which offers a high degree of shape freedom. This makes it easy to ensure the desired rigidity by providing ribs, etc., thereby reinforcing the frame. On the other hand, the suspension cover attached to the frame can also be made of sheet metal. While sheet metal offers advantages such as being easier to manufacture using existing manufacturing processes than aluminum die-casting, sheet metal offers lower shape freedom than aluminum die-casting and tends to increase weight to ensure rigidity.

[0006] In this way, for example, when the input load from the suspension to the inside in the vehicle width direction is transmitted to the frame via the suspension cover due to the up and down displacement of the suspension during normal driving, the frame may not be able to prevent the suspension cover made of sheet metal with low shape freedom and easily increased weight to ensure rigidity from deforming inward toward the frame side, which may result in an adverse effect on handling stability and ride comfort.

[0007] Furthermore, in a structure where the suspension cover is attached to the frame, the cross-section of the frame around the suspension cover decreases along the vehicle width direction. This can cause bending deformation of the frame around the suspension cover during a rear-end collision. While aluminum die-cast frames can utilize their shape freedom to ensure rigidity sufficient to suppress bending deformation, sheet metal frames are difficult to achieve by simply shaping. Consequently, suppressing bending deformation requires excessively increasing mass, leaving room for improvement.

[0008]

Prior art literature

[0009] [Technical problem to be solved by the invention] In view of the above technical problems, the present invention aims to provide a lower body structure of a vehicle. According to the lower body structure of the vehicle, in a structure in which excessive increase in mass is suppressed, a suspension cover is provided on a frame, the cross-section of the frame around the suspension cover along the vehicle width direction is reduced, and the suspension cover is made of sheet metal, even if a load is transmitted from the suspension cover to the inside in the vehicle width direction during normal driving, the inward deformation of the suspension cover can be suppressed, and the bending deformation of the frame can be suppressed during a rear-side collision.

[0010]

Technical means to solve technical problems

[0011] With this structure, the load applied inward in the vehicle width direction from the suspension cover during normal driving is transmitted to the cross member via the load transmission portion, thereby suppressing inward deformation of the suspension cover. Furthermore, in a rear-end collision, although the narrow width portion, which has low rigidity, tends to bend and deform, the cross member suppresses this bending deformation.

[0012] Therefore, excellent handling stability and good ride comfort can be achieved during normal driving, and the rigidity of the lower part of the vehicle body can be ensured against the rear collision load during a rear collision.

[0013] As an aspect of the present invention, the load transmission portion may overlap with an opening formed vertically through the shock absorber mounting surface portion at a front-rear position.

[0014] According to this structure, the opening in the shock absorber mounting surface serves as the shock absorber mounting center. Therefore, the input load from the suspension is large at the front-back position overlapping the opening. Providing the load transfer portion at this position allows for efficient support of the suspension cover. Consequently, inward deformation of the suspension cover can be suppressed in response to inward vehicle widthwise input loads from the suspension.

[0015] As a form of the present invention, it can also be: an inner flange portion for fixing the floor panel is provided on the inner side of the frame in the vehicle width direction, and a connecting surface portion is provided on the load transmission portion, and the connecting surface portion connects the inner part of the peripheral wall portion in the vehicle width direction and the inner flange portion downward as it goes inward in the vehicle width direction, and the floor panel that cooperates with the cross beam to form a closed cross-section portion along the vehicle width direction is extended linearly along the vehicle width direction at a height position of the first inner fixing portion that fixes the connecting surface portion to the inner flange portion.

[0016] According to the above configuration, the cross member cooperates with the floor panel to efficiently transmit load input from the suspension to the suspension cover during normal driving and transmitted via the connecting surface portion toward the vehicle width direction inner side.

[0017] As a form of the present invention, it can also be that: the cross beam has a lower wall portion along the front-to-back direction and a side wall portion extending upward from the front and rear ends of the lower wall portion, and at least one of the front ridge line formed by the corner portion of the lower wall portion and the front side side wall portion along the vehicle width direction and the rear ridge line formed by the corner portion of the lower wall portion and the rear side side wall portion along the vehicle width direction overlaps with the load transfer portion in the front-to-back position.

[0018] According to the above configuration, the front ridgeline and the rear ridgeline of the cross member along the vehicle width direction overlap with the load transmission portion in the front-rear position, thereby improving the efficiency of load transmission from the suspension to the cross member via the load transmission portion.

[0019] As an aspect of the present invention, at least one of the front ridgeline and the rear ridgeline of the cross member may overlap with a ridgeline formed along the vehicle width direction in the load transmission portion in a front-rear position.

[0020] According to the above configuration, when a load is input from the suspension during normal travel, the load can be transferred along the ridges formed on the load transfer portion and the cross member, thereby further improving the efficiency of load transfer from the load transfer portion to the cross member.

[0021] As an aspect of the present invention, the second inner fixing portion fixing the load transmitting portion to the inner wall portion of the frame from the outside in the vehicle width direction and the outer fixing portion fixing the cross member to the inner wall portion of the frame from the inside in the vehicle width direction may overlap each other in front and rear positions.

[0022] According to the above configuration, when a load is input from the suspension during normal travel, the efficiency of transmitting the load from the load transmitting portion to the cross member via the frame can be further improved.

[0023] As an aspect of the present invention, the load transmitting portion may have a shape having a downward opening in a cross section along the front-rear direction, and may be fixed to the frame and have the downward opening closed by a lower wall portion of the frame.

[0024] According to the above configuration, the load transmitting portion can cooperate with the frame that closes the lower opening to form a closed cross section with the lower wall of the frame, thereby increasing the rigidity of the load transmitting portion.

[0025] Therefore, it is possible to further suppress the inward collapse deformation of the suspension cover during normal driving and the bending deformation of the narrow width portion during a rear-side collision.

[0026] As an aspect of the present invention, a lower fixing portion of the horizontal beam fixed to a lower wall portion of the frame from below may overlap the load transmitting portion in a front-rear position.

[0027] According to the above configuration, the lower fixing portion overlaps the load transmission portion at front-rear positions, thereby improving the efficiency of load transmission from the suspension to the cross member via the load transmission portion.

[0028] As an aspect of the present invention, the frame may be composed of a frame front portion and a frame rear portion, and the load transmission portion may be fixed to a joint where the frame front portion and the frame rear portion overlap with each other.

[0029] According to the structure, the connection between the front side portion of the frame and the rear side portion of the frame can be strengthened by the load transfer portion fixed to the connection, and the load transfer efficiency from the load transfer portion to the frame when a load is input from the suspension to the inner side in the vehicle width direction during normal driving can be improved.

[0030] Effects of the invention According to the present invention, a lower body structure of a vehicle can be provided. According to the lower body structure of the vehicle, in a structure in which excessive increase in mass is suppressed, a suspension cover is provided on a frame, the cross-section of the frame around the suspension cover along the vehicle width direction is reduced, and the suspension cover is made of sheet metal, even if a load is transmitted from the suspension cover to the inside in the vehicle width direction during normal driving, the inward deformation of the suspension cover can be suppressed, and the bending deformation of the frame can be suppressed during a rear-side collision. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 is an oblique cross-sectional view of the lower vehicle body structure of this embodiment as viewed from the storage compartment side; Figure 2 To follow Figure 1 An enlarged cross-sectional view of the main part of line A-A along the direction of the arrow; Figure 3 To view from above Figure 2 An oblique cross-sectional view taken along the arrow direction of line BB; Figure 4 for Figure 1 An enlarged view of the main portion of the suspension cover and its surrounding portion, with a portion of the rear frame omitted from the illustration; Figure 5 For the Figure 4 An enlarged cross-sectional view in the direction of the arrow on the C-C line; Figure 6 For the Figure 4 An enlarged cross-sectional view in the direction of the arrow on the D-D line; Figure 7 To follow Figure 4 End view of the main part of the D-D line; Figure 8 To follow Figure 4 An enlarged cross-sectional view of a main portion of line EE along the direction of the arrow; Figure 9 To follow Figure 4 An enlarged cross-sectional view of a main portion of line GG along the direction of the arrow; Figure 10 (a) is along Figure 4 The diagram in the direction of arrow Da, (b) is along Figure 10 (a) Enlarged cross-sectional view in the direction of the arrow on the H-H line. DETAILED DESCRIPTION

[0032] An embodiment of the present invention will be described in detail based on the following drawings.

[0033] The accompanying drawings show a lower vehicle body structure V1 of an automobile according to this embodiment. Figure 1 This is a perspective cross-sectional view taken from the storage compartment side, cutting the vehicle body rear portion V including the lower vehicle body structure V1 in the front-rear direction at the middle position in the vehicle width direction. Figure 2 The upper rear side member 132R (refer to Figure 1 ) and rear floor panel 2 (refer to Figure 1 ) along Figure 1 An enlarged cross-sectional view of the main part of line AA along the arrow direction, Figure 3 It is viewed from above Figure 2 The oblique cross-sectional view in the direction of the arrow of line BB is shown. Figure 4 is Figure 1 The main part of the suspension cover 4 and its surrounding parts is enlarged, with the upper rear member 132R omitted. Figure 5 It is along Figure 4 The enlarged cross-sectional view in the direction of the arrow of the C-C line, Figure 6 It is along Figure 4 The enlarged cross-sectional view in the direction of the arrow on the D-D line. Figure 7 It is along Figure 4 End view of the main part of the D-D line, Figure 8 It is along Figure 4 An enlarged cross-sectional view of the main part of the EE line along the arrow direction, Figure 9 It is along Figure 4 An enlarged cross-sectional view of the main part of the GG line along the arrow direction, Figure 10 (a) is along Figure 4 The diagram shows the direction of the arrow Da, Figure 10 (b) is along Figure 10 (a) Enlarged cross-sectional view in the direction of the arrow on the H-H line.

[0034] In the figure, arrow Rr indicates the rear of the vehicle, arrow U indicates the top of the vehicle, arrow RH indicates the right side of the vehicle, and arrow OUT indicates the outside in the vehicle width direction. In the following description, unless otherwise specified, the terms "front," "rear," "left," "right," "up," and "down" refer to the front, rear, left, right, up, and down directions of the vehicle, respectively. These directions are relative to the passenger seated in the driver's seat.

[0035] The automotive lower body structure V1 of this embodiment is generally bilaterally symmetrical. Therefore, the description will be based on the structure on the right side of the vehicle body, unless otherwise noted. "X" marks in the figure indicate the main spot weld locations, and "O" marks surrounding the "X" marks indicate the weld range. In the following description, reinforcements are abbreviated as "reinforcement members."

[0036] The automobile lower body structure V1 of the present embodiment is applied to the rear vehicle body V. Before describing the lower body structure V1, the upper peripheral structure of the lower body structure V1 in the rear vehicle body V will be described.

[0037] like Figure 1As shown, the upper periphery of the lower vehicle body structure V1 of this embodiment mainly includes side panels 100, roof side rails 101, roof reinforcements 102, rear box reinforcements 103, center pillars 104, rear pillars 105, and bracket members 107 and 108 on the front and rear sides.

[0038] The side panel 100 is located above a wheel house inner 1 a described later and cooperates with the wheel house inner 1 a to form a side wall of a storage compartment of the vehicle body rear portion V. The lower edge of the side panel 100 is joined to the upper edge of the wheel house inner 1 a.

[0039] The roof side rail 101 includes a roof side rail inner member 101a and a roof side rail outer member (not shown). The roof side rail 101 has closed cross-sections 101s extending in the vehicle longitudinal direction at both ends in the vehicle width direction forming the top of the cabin ceiling.

[0040] The roof reinforcement 102 is mounted between the left and right roof side rails 101. It engages with the lower surface of the plate-shaped roof panel, which extends along the vehicle width and fore-aft directions, and supports the panel. The rear edge of the roof panel, along with the rear end of the roof panel, forms a closed cross-section 103s along the vehicle width. The rear panel reinforcement 103 forms the upper edge of the rear storage compartment opening 110, which extends from the storage compartment side toward the rear of the vehicle body.

[0041] The center pillar 104 (so-called C-pillar) forms a closed cross-section portion 104s extending in the vertical direction of the vehicle body, connecting the rear portion of the roof side sill 101 to the rear portion of the side sill 111. The side sill 111 is a vehicle body reinforcement member, and it forms closed cross-section portions 111s extending in the front-rear direction at the left and right ends of the front floor panel (not shown), which forms the cabin floor. The upper portion of the center pillar 104 forms the front edge of the triangular window opening 112. The center pillar 104 is positioned so that its vertical center portion is located at the front edge of the side panel 100, and its lower portion is located at the front edge of the rear wheelhouse 1.

[0042] Rear pillar 105 (so-called D-pillar) defines a closed cross-section portion 105s. This portion extends downward and rearward at an angle from the vehicle widthwise outer end of rear box reinforcement 103, forming the side edge of rear storage compartment opening 110. The upper portion of rear pillar 105 is joined to the rear edge of side panel 100.

[0043] Each of the front and rear bracket members 107 and 108 is joined to the side panel 100 from the storage compartment side. Of these bracket members 107 and 108, the front bracket member 107 forms a closed cross-section portion 107s. This closed cross-section portion 107s extends vertically, connecting the lower portion of the center pillar 104 with the vehicle widthwise outer edge of the upper cross member 51, described later. Of these bracket members 107 and 108, the rear bracket member 108 forms a closed cross-section portion 108s. This closed cross-section portion 108s extends vertically, connecting the upper end of the rear pillar 105 with a portion of the wheel house inner 1a directly above the suspension cover 4, described later.

[0044] Next, the automobile lower body structure V1 according to the present embodiment will be described.

[0045] like Figures 1 to 10 , especially Figure 1 As shown, the automobile lower body structure V1 of the present embodiment mainly includes a rear wheel house 1, a rear floor panel 2, a rear frame 3, a suspension cover 4, and a plurality of rear cross members 51, 53, 55, 57.

[0046] The rear wheelhouse 1 is located below the side panel 100 and has an arched shape with its center portion projecting upward in the front-to-rear direction when viewed from the side of the vehicle. It accommodates the rear wheel and comprises a wheelhouse outer member (not shown) extending outward in the vehicle width direction and a wheelhouse inner member 1a extending inward in the vehicle width direction. The wheelhouse inner member 1a and the wheelhouse outer member are joined together along their peripheries, excluding their lower ends.

[0047] In the rear floor panel 2 , a rear seat chassis 21 and a rear bottom plate 22 are arranged on the front and rear sides, and are integrated with each other or continuously provided as a whole.

[0048] The rear seat chassis 21 is a rear floor on the front side for mounting the rear seat (rear seat) on its upper portion, and the rear floor panel 22 is a rear floor on the rear side for forming the floor of the storage room, and a storage room recess 22a is formed in the rear portion of the rear floor panel 22.

[0049] like Figure 1 、 Figure 7 As shown in FIG. 1 and FIG. 2 , the rear frames 3 are disposed on both left and right sides of the rear floor panel 2 and extend in the front-rear direction.

[0050] like Figure 1 As shown, the front end of the rear frame 3 overlaps the rear end of the side sills 111 provided on the left and right sides of the front floor panel (not shown). Meanwhile, a rear bumper reinforcement (not shown) extending in the vehicle width direction is connected to each rear end of the left and right rear frames 3 to absorb the impact energy during a rear-side collision.

[0051] like Figure 5As shown in the figures, the rear frame 3 includes: an upper wall portion 31 forming the upper surface of the rear frame 3 along the vehicle width direction, a lower wall portion 32 forming the lower surface of the rear frame 3 along the vehicle width direction, an inner wall portion 33 at the inner end in the vehicle width direction of which the upper wall portion 31 and the lower wall portion 32 are connected up and down, and an outer wall portion 34 at the outer end in the vehicle width direction of which the upper wall portion 31 and the lower wall portion 32 are connected up and down.

[0052] The rear frame 3 includes a rear frame lower member 131, whose cross-section along the vehicle width direction is open upward, and a rear frame upper member 132, which closes the opening of the rear frame lower member 131 from above. The rear frame lower member 131 is integrally formed by stamping steel sheets, including the outer wall portion 34, the lower wall portion 32, the inner wall main body portion 33a of the inner wall portion 33 (excluding the upper portion), the lower member inner edge flange portion 35a, and the lower member outer edge flange portion 36a. The lower member inner edge flange portion 35a protrudes approximately horizontally inward in the vehicle width direction from the upper end of the inner wall main body portion 33a. The lower member outer edge flange portion 36a protrudes upward from the upper end of the outer wall portion 34.

[0053] The rear frame upper member 132 is integrally formed by stamping steel plates, comprising the upper wall portion 31, the inner wall upper portion 33b (corresponding to the upper portion of the inner wall portion 33), the upper member inner edge flange portion 35b, and the upper member outer edge flange portion 36b. The upper member inner edge flange portion 35b protrudes inwardly in the vehicle width direction from the lower end of the inner wall upper portion 33b, extending substantially horizontally. The upper member outer edge flange portion 36b protrudes upward from the outer edge of the upper wall portion 31 in the vehicle width direction.

[0054] In addition, regarding the rear frame lower part 131 and the rear frame upper part 132, the lower part inner edge flange portion 35a and the upper part inner edge flange portion 35b are spot welded in a state of overlapping in the up and down directions, and the upper part outer edge flange portion 36b and the lower part outer edge flange portion 36a are spot welded in a state of overlapping in the vehicle width direction.

[0055] Thus, in the rear frame 3 , the rear frame lower member 131 and the rear frame upper member 132 cooperate to form a closed cross-section portion 3 s extending in the front-rear direction, that is, an internal space having a closed cross-section.

[0056] At this time, if Figure 3 、 Figure 9 As shown, the upper inner flange portion 35b and the lower inner flange portion 35a of the rear frame lower member 131 overlap in a manner that sandwiches the outer end of the rear floor panel 22 in the vehicle width direction from both sides, and these three layers are joined by spot welding. Figure 3 As shown, a plurality of the three overlapping spot welds w35 are formed in the front-rear direction.

[0057] In addition, if Figure 1 、 Figure 4As shown, the rear frame 3 extends in the front-rear direction, and the middle portion in the front-rear direction is adjacent to the longitudinal wall-shaped wheel house inner member 1a on the inner side in the vehicle width direction. Figure 5 As shown, the lower member outer edge flange portion 36a to which the upper member outer edge flange portion 36b is joined from the vehicle width direction inner side is joined to the wheel house inner member 1a from the vehicle width direction inner side by spot welding or the like.

[0058] In addition, if Figure 1 、 Figure 4 As shown, the rear frame upper member 132 of the rear frame 3 includes an upper member front member 132F and an upper member rear member 132R as its structural members on the front and rear sides. The connection portion between the rear portion of the upper member front member 132F and the front portion of the upper member rear member 132R is formed as an overlapping connection portion 132C that is joined in a state of overlapping with each other in the front-to-back direction.

[0059] Likewise, if Figure 3 、 Figure 4 、 Figure 8 、 Figure 9 As shown, the rear frame 3 includes a rear frame lower member 131 having a lower front member 131F and a lower rear member 131R as its structural members on the front and rear sides. The connection between the rear portion of the lower front member 131F and the front portion of the lower rear member 131R is formed as an overlapping connection portion 131C, which overlaps and joins in the front-to-back direction. The overlapping connection portion 132C is located forward of the overlapping connection portion 131C.

[0060] In addition, in this embodiment, Figure 3 As shown in FIG. 1 and FIG. 2 , in the overlapping connection portion 131C, the front portion of the lower rear member 131R is arranged to overlap with the rear portion of the lower front member 131F from below.

[0061] like Figure 1 、 Figure 4 As shown, a suspension cover 4 (abbreviated as "suspension cover 4") is provided on the rear frame 3. Figure 6 As shown, the suspension cover 4 is a shock absorber support portion that supports the upper end portion of the rear suspension shock absorber 120 including a damping spring, and includes a shock absorber mounting surface portion 41 and a peripheral wall portion 42 , and is made of sheet metal.

[0062] The suspension cover 4 is provided on the rear frame 3 adjacent to the wheel house inner 1 a on the vehicle width inner side. The upper portion of the suspension cover 4 is stepped relative to the upper surface of the rear frame 3 around the suspension cover 4 and forms a part of the upper surface of the rear frame 3 .

[0063] The structure of the suspension cover 4 and its surrounding areas will be described later.

[0064] like Figure 1As shown, the plurality of rear cross beams 51, 53, 55, 57 include: a front rear cross beam 51, 53 arranged on the front side compared to the suspension cover 4, an intermediate rear cross beam 55 having the same front-to-rear position as the suspension cover 4, and a rear rear cross beam 57 arranged on the rear side compared to the suspension cover 4, and the plurality of rear cross beams 51, 53, 55, 57 are separated from each other in the front-to-rear direction.

[0065] The front rear cross members 51 , 53 are composed of an upper cross member 51 (so-called No. 4 upper cross member) and a lower cross member 53 (so-called No. 4 lower cross member).

[0066] The upper cross member 51 has a downwardly open, hat-shaped cross section along the front-back direction, while the lower cross member 53 has an upwardly open, hat-shaped cross section along the front-back direction. The upper and lower cross members 51 and 53 sandwich the boundary between the rear seat pan 21 and the rear floor panel 22 from the upper and lower sides and are joined to this boundary. Both the upper and lower cross members 51 and 53 define closed cross-sections 52 and 54 extending in the vehicle width direction between the boundary portions. Their widthwise ends are connected to the left and right rear frames 3, respectively.

[0067] like Figure 1 As shown, the cross-sections of the center rear cross-member 55 and the rear side rear cross-members 57 along the front-to-rear direction are both hat-shaped with an upper opening. Both are joined to the rear floor panel 22 from below, forming closed cross-section portions 56 and 58 extending in the vehicle width direction between them and the rear floor panel 22. Furthermore, both the center rear cross-member 55 and the rear side rear cross-members 57 extend below the rear floor panel 22 in the width direction, with both widthwise ends connected to the left and right rear frames 3, respectively.

[0068] like Figure 3 、 Figure 6 、 Figure 7 、 Figure 9 As shown, the intermediate rear cross member 55 and the overlapping connection portion 131C that overlaps and connects the rear end portion of the lower front side member 131F and the front end portion of the lower rear side member 131R of the rear frame 3 in the front-rear direction are provided at the same front-rear position.

[0069] The structure of the middle rear cross member 55 will be described in further detail.

[0070] like Figure 3 、 Figure 9 As shown, the middle rear cross beam 55 includes: a lower wall portion 55a, a front wall portion 55b and a rear wall portion 55c extending upward from the front and rear ends of the lower wall portion 55a, a front edge flange portion 55d extending forward from the upper end of the front wall portion 55b, and a rear edge flange portion 55e extending rearward from the upper end of the rear wall portion 55c. The cross section of the middle rear cross beam 55 along the front-to-back direction is a hat shape with an upper opening.

[0071] like Figure 1As shown, the front edge flange portion 55d and the rear edge flange portion 55e of the intermediate rear cross member 55 are joined to the rear floor panel 22 from below, except for the two end portions in the vehicle width direction. Thus, the intermediate rear cross member 55 defines a closed cross-section portion 56 extending linearly in the vehicle width direction between the intermediate rear cross member 55 and the rear floor panel 22.

[0072] Here, if Figure 3 、 Figure 9 As shown, ridge lines extending linearly along the vehicle width direction are formed at the corners between the front wall portion 55b and the front edge flange portion 55d, the corners between the front wall portion 55b and the lower wall portion 55a, the corners between the rear wall portion 55c and the rear edge flange portion 55e, and the corners between the rear wall portion 55c and the lower wall portion 55a on the intermediate rear cross member 55. These ridge lines are, in the order of the corners, a front upper ridge line 551, a front lower ridge line 552, a rear upper ridge line 553, and a rear lower ridge line 554.

[0073] And, as Figure 6 、 Figure 7 、 Figure 9 As shown, a front outer edge flange portion 55f, a rear outer edge flange portion 55g, and a lower outer edge flange portion 55h are provided at both end portions of the intermediate rear cross member 55 in the vehicle width direction.

[0074] like Figure 9 As shown, the front outer edge flange portions 55f protrude forward from the front wall portion 55b at both ends of the intermediate rear cross member 55 in the vehicle width direction and protrude downward from the front edge flange portion 55d and are spot welded to the inner wall portion 33 of the rear frame 3 .

[0075] The rear outer edge flange portions 55 g protrude rearwardly relative to the rear wall portion 55 c at both ends of the intermediate rear cross member 55 in the vehicle width direction and downwardly relative to the rear edge flange portion 55 e and are spot welded to the inner wall portion 33 of the rear frame 3 .

[0076] like Figure 6 、 Figure 7 As shown, lower outer edge flange portions 55h are formed at both ends of the intermediate rear cross member 55 in the vehicle width direction, projecting outward in the vehicle width direction relative to the lower wall portion 55a, and are spot welded to the lower wall portion 32 of the overlapping connection portion 131C of the rear frame 3. Thus, as described above, both ends of the intermediate rear cross member 55 in the width direction are connected to the corresponding left and right rear frames 3, respectively.

[0077] Here, Figure 9 Among the "×" in the figure, the "×" related to the middle rear cross member 55 represents the spot welding portion with the rear frame 3. Among the above-mentioned multiple spot welding portions, the spot welding portion provided in the front outer edge flange portion 55f of the middle rear cross member 55 is the front outer fixing portion w5a, and the spot welding portion provided in the rear outer edge flange portion 55g of the middle rear cross member 55 is the rear outer fixing portion w5b. Figure 6 As shown, the spot welding portion provided in the lower outer edge flange portion 55h of the intermediate rear cross member 55 serves as the lower outer fixing portion w5c.

[0078] Next, the structure of the suspension cover 4 and its surrounding areas will be described in detail.

[0079] As described above, the suspension cover 4 includes the shock absorber mounting surface portion 41 and the peripheral wall portion 42 (see Figures 2 to 5 、 Figure 6 、 Figure 8 、 Figure 9 ).

[0080] The shock absorber mounting surface 41 corresponds to the upper surface of the suspension cover 4 and is in the shape of a flat plate along the upper surface of the rear frame 3. An opening 46 is formed in the center of the shock absorber mounting surface 41 in the top view in the vertical direction. Figure 6 ) is mounted on the periphery of the opening 46 of the shock absorber mounting surface portion 41 from the lower surface side in a manner such that the top, that is, the shock absorber top, protrudes upward from the opening 46.

[0081] Here, if Figure 6 As shown, the shock absorber mounting surface 41 is an inclined surface that slopes downward, generally linearly, as it approaches the vehicle width inward. Consequently, the rear suspension shock absorber 120 is mounted on the shock absorber mounting surface 41, tilted slightly downward and outward in the vehicle width. Therefore, due to the vertical displacement of the suspension during normal driving, not only vertical loads but also loads inward in the vehicle width are transferred from the rear suspension to the vehicle body.

[0082] like Figure 3 、 Figure 5 、 Figure 6 As shown, the peripheral wall portion 42 is in the shape of a plate, that is, a vertical wall, extending downward from the peripheral edge of the shock absorber mounting surface portion 41 located above, excluding the edge portion on the outer side in the vehicle width direction. Figure 3 As shown in the figures, the peripheral wall portion 42 includes a peripheral wall inner portion 43 located on the inner side in the vehicle width direction, a front first partition wall portion 44 located in front of the peripheral wall inner portion 43 , and a rear first partition wall portion 45 located on the rear side of the peripheral wall inner portion 43 .

[0083] The front first partition wall portion 44 and the rear first partition wall portion 45 are arranged in a front-to-rear pair across the peripheral wall inner portion 43. The front first partition wall portion 44 has a curved shape that curves outward in the vehicle width direction as it moves forward away from the peripheral wall inner portion 43, and forms the front surface of the peripheral wall portion 42. The rear first partition wall portion 45 has a curved shape that curves outward in the vehicle width direction as it moves rearward away from the peripheral wall inner portion 43, and forms the rear surface of the peripheral wall portion 42.

[0084] Therefore, if Figure 5 、 Figure 6 As shown, the peripheral wall portion 42 has a curved surface shape. It projects in a substantially semicircular arc shape in a plan view relative to the outer wall portion 34 of the rear frame 3 located adjacent to the front and rear ends of the suspension cover 4, toward the closed cross-section portion 3s (internal space) of the rear frame 3. The peripheral wall portion 42, thus projecting toward the closed cross-section portion 3s, also serves as at least a portion of the outer wall portion 34 of the rear frame 3 located adjacent to the suspension cover 4 in the front-rear direction.

[0085] And as Figure 5 、 Figure 8 As shown, the outer wall portion 34 of the rear frame 3 adjacent to the front and rear of the suspension cover 4 includes: an outer wall lower portion 341 extending approximately vertically upward from the lower wall portion 55a of the rear frame 3, and an outer wall upper portion 342 that tilts upward and outward in the vehicle width direction from the upper end of the first portion.

[0086] Specifically, if Figure 6 As shown, the portion of the outer wall portion 34 of the rear frame 3 corresponding to the suspension cover 4 is partially recessed inward in the vehicle width direction relative to the outer wall portion of the adjacent front and rear portions, as a peripheral wall portion 42. Therefore, at the portion of the rear frame 3 adjacent to the suspension cover 4 on the vehicle width direction inner side, the widthwise dimension of the closed cross-section portion 3s of the rear frame 3 is reduced compared to the portion adjacent to the suspension cover 4 on the front and rear sides, forming a narrowed portion 37.

[0087] In addition, if Figure 6 As shown, the lower edge 42a of the peripheral wall portion 42 of the suspension cover 4 is fixed by spot welding from the vehicle width direction inner side to the lower portion of the outer wall portion 34 that rises upward in a flange shape from the vehicle width direction outer end of the lower wall portion 32 of the rear frame lower member 131.

[0088] like Figure 6 As shown in FIG. 1 , an outer edge flange portion 41a is formed at the outer end in the vehicle width direction of the shock absorber mounting surface portion 41 of the suspension cover 4 and the outer end in the vehicle width direction of the peripheral wall portion 42. Figure 4 As shown, the outer edge flanges 41a of the shock absorber mounting surface 41 and the peripheral wall 42 are spot-welded to the longitudinal wall-shaped wheel house inner 1a from the vehicle widthwise inner side. Thus, the suspension cover 4 is disposed adjacent to the vehicle widthwise inner side of the wheel house inner 1a and forms part of the rear frame 3.

[0089] like Figure 5 、 Figure 6 、 Figure 8 、 Figure 9 As shown, at a front-rear position of the rear frame 3 corresponding to the suspension cover 4 , the outer edge flange portion 36 b of the rear frame upper member 132 located on the outside in the vehicle width direction is joined along the upper portion of the peripheral wall portion 42 by spot welding or the like, and is formed as a part of the peripheral wall portion 42 .

[0090] like Figures 2 to 6 、 Figure 8 As shown, the automobile lower body structure V1 of this embodiment further includes a node member 60 serving as a load transmission portion connecting the suspension cover 4 and the intermediate rear cross member 55 in the closed cross-section portion 3 s of the narrow portion 37 of the rear frame 3 .

[0091] like Figure 8 As shown in the figures, the node component 60 includes: a connecting surface portion 61 serving as an upper wall portion (upper surface portion), a front side second partition wall portion 62 serving as a front wall portion extending downward from the front end of the connecting surface portion 61, a rear side second partition wall portion 63 serving as a rear wall portion extending downward from the rear end of the connecting surface portion 61, a front edge flange portion 64 extending forward from the lower end of the front side second partition wall portion 62, and a rear edge flange portion 65 extending rearward from the lower end of the rear side second partition wall portion 63, and the cross-section of the node component 60 along the front-to-back direction is a hat shape with an opening at the bottom.

[0092] In the node component 60, the front edge flange portion 64 and the rear edge flange portion 65 are joined to the lower wall portion 32 of the rear frame 3 from above, and the lower opening is blocked by the lower wall portion 32 of the rear frame 3, forming a closed cross-section portion 6s extending linearly in the vehicle width direction between the lower wall portion 32 of the rear frame 3.

[0093] Furthermore, in the joint member 60, ridge lines extending linearly in the vehicle width direction are formed at the corners between the front second partition wall portion 62 and the front edge flange portion 64, the corners between the front second partition wall portion 62 and the connecting surface portion 61, the corners between the rear second partition wall portion 63 and the rear edge flange portion 65, and the corners between the rear second partition wall portion 63 and the connecting surface portion 61. These ridge lines are, in the order of the aforementioned corners, a front lower ridge line 601, a front upper ridge line 602, a rear lower ridge line 603, and a rear upper ridge line 604.

[0094] Here, if Figure 2 As shown, the front lower ridgeline 552 and the rear lower ridgeline 554 of the intermediate rear cross beam 55 both overlap with the node member 60 in the front and rear positions. Figure 2 As shown by the imaginary straight line La in the figure, the front lower edge 552 of the middle rear cross beam 55 overlaps with the front upper edge 602 of the node component 60 in the front and rear positions, and the rear lower edge 554 of the middle rear cross beam 55 overlaps with the rear upper edge 604 of the node component 60 in the front and rear positions.

[0095] And, as Figure 3 、 Figure 8 As shown, a front outer edge flange portion 66 a , a rear outer edge flange portion 66 b , and an upper outer edge flange portion 66 c are provided on the outer edge of the joint member 60 in the vehicle width direction.

[0096] The front outer edge flange portion 66a is formed so as to protrude forward relative to the front second partition wall portion 62 at the outer end portion in the vehicle width direction of the node member 60, and is fixed by spot welding while overlapping with the vehicle width direction inner portion of the front first partition wall portion 44 of the peripheral wall portion 42 from the vehicle width direction inner side. The rear outer edge flange portion 66b is formed so as to protrude rearward relative to the rear second partition wall portion 63 at the outer end portion in the vehicle width direction of the node member 60, and is fixed by spot welding while overlapping with the vehicle width direction inner portion of the rear first partition wall portion 45 of the peripheral wall portion 42 from the vehicle width direction inner side.

[0097] The upper outer edge flange portion 66c is formed to protrude upward from the vehicle width direction outer end portion of the connecting surface portion 61 of the node member 60 and is fixed by spot welding while overlapping with the peripheral wall inner portion 43 of the peripheral wall portion 42 from the vehicle width direction inner side.

[0098] And also Figure 2 As shown, a front inner edge flange portion 67 a , a rear inner edge flange portion 67 b , and an upper inner edge flange portion 67 c are provided on the inner edge of the node member 60 in the vehicle width direction.

[0099] like Figure 2 、 Figure 5 As shown, the front inner edge flange portion 67a is formed at the inner end portion of the node member 60 in the vehicle width direction, protruding forward relative to the front second partition wall portion 62, and is fixed by spot welding in a state where it overlaps with the inner wall portion 33 of the rear frame 3 from the outer side in the vehicle width direction. Figure 2 As shown, the rear inner edge flange portion 67b is formed at the inner end portion of the node component 60 in the vehicle width direction, protruding rearward relative to the rear second partition wall portion 63, and is fixed by spot welding while overlapping with the inner wall portion 33 of the rear frame 3 from the outside in the vehicle width direction.

[0100] like Figure 2 、 Figure 3 As shown, the upper inner edge flange portion 67c protrudes inward in the vehicle width direction from the inner end portion of the connecting surface portion 61 of the node component 60 in the vehicle width direction, and is formed in pairs front and rear. The upper inner edge flange portions 67c on each front and rear side are fixed by spot welding from above in a state of overlapping with the lower inner edge flange portion 35a of the rear frame lower part 131.

[0101] The connection between the lower member inner edge flange portion 35a of the rear frame lower member 131 and the upper side inner edge flange portions 67c on the front and rear sides of the node member 60 will be described in further detail.

[0102] When the upper inner edge flange portion 67c of each front and rear side is engaged with the lower inner edge flange portion 35a of the rear frame lower member 131, as shown in FIG. Figure 3 、 Figure 9As shown, at the overlapping connection portion 131C of the rear portion of the lower front side member 131F of the rear frame 3 and the front portion of the lower rear side member 131R, the upper inner edge flange portions 67c on the front and rear sides of the node member 60 and the rear portion of the lower front side member 131F of the rear frame 3 are overlapped by clamping the front portion of the lower rear side member 131R of the rear frame 3 from the upper and lower sides, and the three layers are joined into one by spot welding.

[0103] Therefore, if Figure 3 、 Figure 6 As shown, the connecting surface portion 61 of the node member 60, which is in the shape of a surface along the vehicle width direction and the front-to-back direction, overlaps with the overlapping connecting portion 131C of the rear frame 3 in the front-to-back position, and is connected and fixed to the overlapping connecting portion 131C via the upper inner edge flange portion 67c.

[0104] The node member 60 connects the peripheral wall portion 42 and the inner portion of the rear frame 3 in the vehicle width direction (the ridge extending in the front and rear directions between the inner wall portion 33 and the inner edge flange portion 35a of the lower part) at the front and rear positions of the above-mentioned rear frame 3 corresponding to the suspension cover 4. Therefore, the closed cross-section portion 3s of the rear frame 3 can be divided front and rear by any of the front second partition wall portion 62 and the rear second partition wall portion 63.

[0105] That is, Figures 2 to 6 、 Figure 8 As shown, the front second partition wall portion 62 cooperates with the front first partition wall portion 44 to partition the closed cross-section portion 3s of the rear frame 3 front to back, and the rear second partition wall portion 63 cooperates with the rear first partition wall portion 45 to partition the closed cross-section portion 3s of the rear frame 3 front to back.

[0106] like Figure 6 As shown, the connecting surface portion 61 of the node member 60 is joined to the peripheral wall portion 42 via the upper outer edge flange portion 66c, and is joined to the inner edge flange of the rear frame lower member 131 via the upper inner edge flange portion 67c. In addition, the upper outer edge flange portion 66c of the node member 60, which is joined to the peripheral wall inner portion 43 of the peripheral wall portion 42, is joined and fixed to a position above the middle position hc of the peripheral wall portion 42 in the vertical direction.

[0107] Thus, in the node member 60 , the joining position of the upper outer edge flange portion 66 c with the peripheral wall portion 42 is located above the joining position of the upper inner edge flange portion 67 c with the lower member inner edge flange portion 35 a of the rear frame lower member 131 .

[0108] Therefore, the connecting surface portion 61 of the node component 60 connects the inner side portion 43 of the peripheral wall portion 42 and the lower inner edge flange portion 35a of the rear frame 3 in the closed cross-section portion 3s of the narrow width portion 37 in a posture that is linearly inclined downward toward the inner side in the vehicle width direction.

[0109] like Figures 2 to 4 、 Figures 6 to 8 As shown, at least the connecting surface portion 61 of the node member 60 in the front-to-back direction overlaps with the opening portion 46 formed through the shock absorber mounting surface portion 41 in the front-to-back position. In this embodiment, the connecting surface portion 61, the front second partition wall portion 62, the rear second partition wall portion 63, the upper inner edge flange portion 67c, and the upper outer edge flange portion 66c of the node member 60 overlap with the opening portion 46 of the shock absorber mounting surface portion 41 in the front-to-back position.

[0110] Here, if Figure 3 、 Figure 8 As shown, among the multiple spot welds of the node member 60 with respect to the peripheral wall portion 42, the front and rear spot welds on the upper outer edge flange portion 66c of the node member 60 are the upper outer fixing portion w6a, and the upper and lower spot welds on the front outer edge flange portion 66a are the front outer fixing portion w6b. The upper and lower spot welds on the rear outer edge flange portion 66b are the rear outer fixing portion w6c.

[0111] like Figure 2 As shown, among the multiple spot welding parts of the node component 60 for the rear frame 3, the front and rear two spot welding parts in the upper inner edge flange portion 67c of the node component 60 are the upper inner fixing portion w6e, the spot welding part in the front inner edge flange portion 67a is the front inner fixing portion w6f, and the spot welding part in the rear inner edge flange portion 67b is the rear inner fixing portion w6g.

[0112] like Figure 3 As shown by the imaginary straight line Lb in the figure, the upper outer fixing portion w6a on the front side and the upper inner fixing portion w6e on the front side are arranged at overlapping front and rear positions, and the upper outer fixing portion w6a on the rear side and the upper inner fixing portion w6e on the rear side are arranged at overlapping front and rear positions.

[0113] like Figure 3 、 Figure 9 As shown, the spot welding portion w35 in which the outer edge of the rear floor panel 2 in the vehicle width direction is clamped in the upper and lower directions by the lower inner edge flange portion 35a of the rear frame lower member 131 and the upper inner edge flange portion 35b of the rear frame upper member 132 so as to overlap and be joined as one in this state is located between the upper inner fixing portions w6e on the front and rear sides in the overlapping connection portion 131C of the rear frame 3.

[0114] The rear floor panel 22 is provided at the height of the upper inner fixing portions w6e on the front and rear sides, and extends substantially horizontally and linearly in the vehicle width direction.

[0115] Figure 9Numbers 6 and 7 in the figure are through holes formed in these components 131R, 55 to avoid interference between the welding gun arranged from below and the front part of the lower rear side component 131R of the rear frame 3 and the front part of the lower rear side component 131R and the lower wall part 55a of the middle rear cross beam 55 when forming three layers of overlapping spot welding parts w35 between the front and rear positions of the upper inner fixing parts w6e on the front and rear sides.

[0116] And also Figure 2 、 Figure 9 、 Figure 10 As shown in (a) and (b), the front outer edge flange 55f of the intermediate rear cross member 55 overlaps the front inner edge flange 67a of the node member 60 in a front-to-back position. Specifically, the front outer fixing portion w5a of the intermediate rear cross member 55 overlaps the front inner fixing portion w6f of the node member 60 in a front-to-back position.

[0117] Likewise, if Figure 2 、 Figure 9 As shown, the rear outer edge flange portion 55g of the intermediate rear cross member 55 overlaps the rear inner edge flange portion 67b of the node member 60 in the front-rear position. Figure 2 、 Figure 9 As shown, the rear outer fixing portion w5b of the intermediate rear cross member 55 and the rear inner fixing portion w6g of the node member 60 overlap in the front-rear position.

[0118] And as Figure 6 As shown, the lower outer edge flange portion 55h of the intermediate rear cross member 55, more specifically, the lower outer fixing portion w5c and the node member 60, more specifically, the connecting surface portion 61, overlap in the front-rear position.

[0119] And also Figure 2 、 Figure 3 、 Figure 6 、 Figure 7 、 Figure 9 As shown, as described above, the middle rear cross member 55 is provided at a front-rear position overlapping with the suspension cover 4 , but in this example, the middle rear cross member 55 is arranged at a front-rear position overlapping with the shock absorber top, that is, the opening 46 of the shock absorber mounting surface 41 .

[0120] like Figure 1 、 Figure 4 As shown, the lower vehicle body structure V1 of the automobile of the present embodiment comprises: a rear frame 3 forming a closed cross-section portion 3s extending in the front-rear direction on the vehicle width direction outer side of the rear floor panel 2 (floor panel); a rear suspension shock absorber 120 (see FIG. 1 ) provided on the rear frame 3 and supporting the rear suspension shock absorber 120 (see FIG. 1 ). Figure 6 ) (suspension) sheet metal suspension cover 4; wherein, as Figures 2 to 9As shown, the suspension cover 4 has a shock absorber mounting surface portion 41 along the upper surface of the rear frame 3 and a peripheral wall portion 42 extending downward from the peripheral edge of the shock absorber mounting surface portion 41. Figures 2 to 6 As shown, the rear frame 3 has a narrow portion 37 at a position adjacent to the suspension cover 4 on the inner side in the vehicle width direction. Compared with the position adjacent to the suspension cover 4 in the front-rear direction, the closed cross-section portion 3s of the narrow portion 37 along the vehicle width direction is reduced. An intermediate rear cross beam 55 (cross beam) extending in the vehicle width direction and arranged at the same front-rear position as the suspension cover 4 is provided on the inner side in the vehicle width direction compared to the rear frame 3. A node member 60 serving as a load transfer portion is provided in the narrow portion 37. The node member 60 serving as the load transfer portion connects the suspension cover 4 and the intermediate rear cross beam 55 and can transfer the input load from the rear suspension shock absorber 120 from the suspension cover 4 to the intermediate rear cross beam 55.

[0121] According to this structure, the load applied inward in the vehicle width direction from the suspension cover 4 during normal driving is transmitted to the intermediate rear cross member 55 via the joint member 60, thereby suppressing inward deformation of the suspension cover 4. Furthermore, during a rear-end collision, although the narrow width portion 37, which has low rigidity, tends to bend and deform, the intermediate rear cross member 55 can suppress this bending deformation of the narrow width portion 37.

[0122] Specifically, the rear frame 3 has a narrow portion 37, whose dimensions are reduced in the vehicle width direction, located adjacent to the suspension cover 4 on the vehicle widthwise inner side. This tends to reduce rigidity in the vehicle width direction. In contrast, in this embodiment, an intermediate rear cross member 55 is provided on the vehicle widthwise inner side of the rear frame 3, at the same front-to-rear position as the narrow portion 37. Therefore, even if the narrow portion 37 were to bend inwardly in the vehicle width direction during a rear-end collision, the intermediate rear cross member 55 provides support, thereby preventing the narrow portion 37 from bending inwardly in the vehicle width direction.

[0123] As a form of the present invention, Figure 2 、 Figure 3 、 Figure 6 、 Figure 8 As shown, the node member 60 overlaps with the opening portion 46 formed through the shock absorber mounting surface portion 41 in the up-down direction at a front-back position.

[0124] According to the above structure, the opening 46 is also the mounting center of the rear suspension shock absorber 120 in the shock absorber mounting surface 41. Therefore, the input load from the rear suspension shock absorber 120 during normal driving is large at the position overlapping with the opening 46 in the front-back position. Therefore, by providing the joint member 60 at the above position, the suspension cover 4 can be supported efficiently. Therefore, it is possible to effectively support the suspension cover 4 with respect to the load from the rear suspension shock absorber 120 during normal driving (see Figure 6 ) inward in the vehicle width direction suppresses the inward deformation of the suspension cover 4.

[0125] As a form of the present invention, it can also be: Figure 2 、 Figure 3 、 Figure 6 、 Figure 7 、 Figure 9 As shown, the rear frame 3 has a lower inner flange portion 35a (inner flange portion) on the inner side in the vehicle width direction to which the rear floor panel 2 is fixed, and the node member 60 has a connecting surface portion 61. The connecting surface portion 61 connects the inner side portion 43 of the peripheral wall portion 42 (the inner side portion in the vehicle width direction) and the lower inner flange portion 35a via the upper inner flange portion 67c as it moves downward toward the inner side in the vehicle width direction. Figure 6 、 Figure 7 、 Figure 9 As shown, the rear floor panel 2, which cooperates with the middle rear cross member 55 to form a closed cross-section portion 56 along the vehicle width direction, is fixed to the upper inner fixing portion w6e (see Figure 9 The height position of the (inner fixing portion) extends linearly along the vehicle width direction.

[0126] According to the above structure, the middle rear cross member 55 can cooperate with the rear floor panel 2 to absorb the load from the rear suspension shock absorber 120 (see FIG. Figure 6 ) The load input to the suspension cover 4 and transmitted via the connecting surface portion 61 is efficiently transmitted toward the vehicle width direction inner side.

[0127] As a form of the present invention, Figure 3 、 Figure 9 As shown, the middle rear cross member 55 has a lower wall portion 55a along the front-to-back direction and a front wall portion 55b and a rear wall portion 55c (side wall portion) extending upward from the front and rear ends of the lower wall portion 55a. Figure 3 As shown, the front lower ridge 552 (front side ridge) formed by the corner portion of the lower wall portion 55a and the front wall portion 55b along the vehicle width direction and the rear lower ridge 554 (rear side ridge) formed by the corner portion of the lower wall portion 55a and the rear wall portion 55c on the rear side along the vehicle width direction both overlap with the node component 60 in the front and rear positions.

[0128] According to the structure, the front lower ridge line 552 and the rear lower ridge line 554 of the middle rear cross beam 55 along the vehicle width direction overlap with the node member 60 in the front and rear positions, thereby improving the efficiency of transferring load from the suspension via the node member 60 to the middle rear cross beam 55.

[0129] As a form of the present invention, Figure 2 As shown, the front lower ridgeline 552 of the intermediate rear cross member 55 overlaps with the front upper ridgeline 602 (ridgeline) formed along the vehicle width direction in the node member 60 at a front-back position, and the rear lower ridgeline 554 of the intermediate rear cross member 55 overlaps with the rear upper ridgeline 604 (ridgeline) formed along the vehicle width direction in the node member 60 at a front-back position (refer to Figure 2 The imaginary straight line La in the figure).

[0130] According to the above structure, during normal driving, the rear suspension shock absorber 120 (refer to Figure 9 ) When there is load input, the load can be transferred from the front upper edge 602 along the front lower edge 552 on the front side of the node component 60 and the intermediate rear cross beam 55, and the load can be transferred from the rear upper edge 604 along the rear lower edge 554 on the rear side of the node component 60 and the intermediate rear cross beam 55, thereby further improving the efficiency of transferring the load from the node component 60 to the intermediate rear cross beam 55.

[0131] As an aspect of the present invention, it can also be: Figure 2 、 Figure 9 、 Figure 10 As shown in (a) and (b), the node member 60 has a front inner fixing portion w6f and a rear inner fixing portion w6g (inner fixing portion) fixed to the inner wall portion 33 of the rear frame 3 from the outside in the vehicle width direction, and the intermediate rear cross beam 55 has a front outer fixing portion w5a and a rear outer fixing portion w5b (outer fixing portion) fixed to the inner wall portion 33 of the rear frame 3 from the inside in the vehicle width direction, the front inner fixing portion w6f and the front outer fixing portion w5a overlap with each other in the front-to-back position, and the rear inner fixing portion w6g and the rear outer fixing portion w5b overlap with each other in the front-to-back position.

[0132] According to the above structure, when a load is input from the suspension during normal running, the efficiency of transmitting the load from the node member 60 to the intermediate rear cross member 55 via the rear frame 3 can be further improved.

[0133] As a form of the present invention, Figure 8 As shown, the node member 60 has a shape with a downward opening in the cross section along the front-rear direction, and is fixed to the rear frame 3 with the lower opening closed by the lower wall portion 32 of the rear frame 3 .

[0134] According to the above structure, the node member 60 can cooperate with the rear frame 3 that closes the lower opening to form the closed cross-section portion 6 s between the node member 60 and the lower wall portion 32 of the rear frame 3 , thereby improving the rigidity of the node member 60 .

[0135] Therefore, it is possible to further suppress the inward collapse deformation of the suspension cover 4 during normal driving and the bending deformation of the narrow width portion 37 during a rear-side collision.

[0136] As a form of the present invention, Figure 6 As shown, the lower outer fixing portion w5 c (lower fixing portion) fixing the lower outer edge flange portion 55 h of the intermediate rear cross member 55 to the lower wall portion 32 of the rear frame 3 from below overlaps the node member 60 in the front-rear position.

[0137] According to the above configuration, the lower outer fixing portion w5 c overlaps with the front-rear position of the node member 60 , thereby improving the efficiency of load transmission from the suspension cover 4 to the intermediate rear cross member 55 via the node member 60 .

[0138] As a form of the present invention, Figure 6 As shown, the rear frame 3 is composed of a lower front side member 131F (front side portion of the rear frame) and a lower rear side member 131R (rear side portion of the rear frame), and a node member 60 is fixed to the overlapping connection portion 131C (the connection portion where the front side portion of the rear frame and the rear side portion of the rear frame overlap with each other) of the lower front side member 131F and the lower rear side member 131R.

[0139] According to the structure, the overlapping connection part 131C can be strengthened by the node member 60 fixed to the overlapping connection part 131C of the lower front side member 131F and the lower rear side member 131R, and the load transfer efficiency from the node member 60 to the rear frame 3 when a load is input from the rear suspension shock absorber 120 to the suspension cover 4 inward in the vehicle width direction during normal driving can be improved.

[0140] In the correspondence between the structure of the present invention and the above-mentioned embodiment, the vehicle corresponds to the automobile, and similarly, The floor panel corresponds to the rear floor panel 2, The frame corresponds to the rear frame 3, The inner flange portion corresponds to the lower inner flange portion 35a. The crossbeam corresponds to the middle rear crossbeam 55, The lower wall portion corresponds to the lower wall portion 55a, The side wall portion on the front side corresponds to the front wall portion 55b. The side wall portion on the rear side corresponds to the rear wall portion 55c. The front side of the rear frame corresponds to the lower front side member 131F. The rear side portion of the rear frame corresponds to the lower rear side member 131R. The joint portion where the front side portion of the rear frame and the rear side portion of the rear frame overlap corresponds to the overlapping connection portion 131C. The front side ridgeline corresponds to the front lower ridgeline 552 of the middle rear cross beam 55. The rear side ridgeline corresponds to the rear lower ridgeline 554 of the middle rear cross member 55. The ridges of the node member correspond to the front upper ridge 602 and the rear upper ridge 604 of the node member 60. The outer fixing portion corresponds to the front outer fixing portion w5a and the rear outer fixing portion w5b. The lower fixing portion corresponds to the lower outer fixing portion w5c. The first inner fixing portion corresponds to the upper inner fixing portion w6e. The second inner fixing portion corresponds to the front inner fixing portion w6f and the rear inner fixing portion w6g. The suspension corresponds to the rear suspension shock absorber 120 , but the present invention is not limited to the structure of the above-mentioned embodiment, and various embodiments are possible.

[0141] For example, in this embodiment, the front lower ridge 552 (front side ridge) and the rear lower ridge 554 (rear side ridge) of the middle rear cross beam 55 both overlap with the node component 60 in the front and rear positions, but the present invention can also be such that one side of the above-mentioned ridges 552, 554 is set at a front and rear position overlapping with the node component 60.

[0142] In addition, in this embodiment, the front lower ridge 552 (front side ridge) of the middle rear cross beam 55 and the front upper ridge 602 (ridge) of the node component 60 overlap in front and rear positions, and the rear lower ridge 554 (rear side ridge) of the middle rear cross beam 55 and the rear upper ridge 604 (ridge) of the node component 60 overlap in front and rear positions, but the present invention can also have only the front and rear positions of a certain front and rear ridge of the middle rear cross beam 55 and the node component 60 overlap.

[0143] And for example, in this embodiment, the front inner fixing portion w6f of the node component 60 and the front outer fixing portion w5a of the middle rear cross beam 55 overlap with each other in the front and rear positions, and the rear inner fixing portion w6g of the node component 60 and the rear outer fixing portion w5b of the middle rear cross beam 55 overlap with each other in the front and rear positions, but the present invention can also have only the front side fixing portion w6f, w5a and the rear side fixing portion w6g, w5b having the front and rear positions overlapping.

[0144]

Number Description

Claims

1. A vehicle lower body structure comprising: a frame constituting a closed cross-section portion extending in the front-rear direction on the vehicle width direction outer side of the floor panel; A suspension cover made of sheet metal provided on the frame and supporting the suspension; wherein, The suspension cover includes a shock absorber mounting surface portion along the upper surface of the frame and a peripheral wall portion extending downward from a peripheral edge of the shock absorber mounting surface portion. The frame has a narrow portion at a portion adjacent to the suspension cover inward in the vehicle width direction, wherein the closed cross-section of the narrow portion along the vehicle width direction is smaller than that of a portion adjacent to the suspension cover in the front-rear direction. A cross member extending in the vehicle width direction and arranged at the same front-rear position as the suspension cover is provided on the vehicle width direction inner side of the frame. The narrow width portion includes a load transmission portion that couples the suspension cover and the cross member and is capable of transmitting an input load from the suspension from the suspension cover to the cross member.

2. The vehicle lower body structure according to claim 1, wherein: The load transmission portion overlaps with an opening formed through the shock absorber mounting surface portion in the up-down direction at a front-back position.

3. The vehicle lower body structure according to claim 1, wherein: The frame has an inner flange portion on the inner side in the vehicle width direction to which the floor panel is fixed, and the load transmission portion has a connecting surface portion, which connects the inner part of the peripheral wall portion in the vehicle width direction and the inner flange portion downward as it goes inward in the vehicle width direction. The floor panel, which cooperates with the cross member to form a closed cross-section portion along the vehicle width direction, extends linearly in the vehicle width direction at a height position where the connecting surface portion is fixed to the first inner fixing portion of the inner flange portion.

4. The vehicle lower body structure according to claim 1, wherein: The cross beam has a lower wall portion along the front-rear direction and side walls extending upward from both front and rear ends of the lower wall portion. At least one of the front ridge line formed by the corner portion of the lower wall portion and the front side wall portion along the vehicle width direction and the rear ridge line formed by the corner portion of the lower wall portion and the rear side wall portion along the vehicle width direction overlaps with the load transfer portion in a front-rear position.

5. The vehicle lower body structure according to claim 4, characterized in that: At least one of the front ridgeline and the rear ridgeline of the cross member overlaps with a ridgeline formed along the vehicle width direction in the load transmission portion at a front-rear position.

6. The vehicle lower body structure according to claim 1, wherein: A second inner fixing portion fixing the load transmitting portion to the inner wall of the frame from the vehicle width direction outer side and an outer fixing portion fixing the cross member to the inner wall of the frame from the vehicle width direction inner side overlap each other in front and rear directions.

7. The vehicle lower body structure according to claim 1, wherein: The load transmitting portion has a shape having a downward opening in a cross section along the front-rear direction, and is fixed to the frame so that the downward opening is closed by a lower wall portion of the frame.

8. The vehicle lower body structure according to claim 1, wherein: A lower fixing portion of the cross member fixed to the lower wall portion of the frame from below overlaps the load transmitting portion at a front-rear position.

9. The vehicle lower body structure according to claim 1, wherein: The frame is composed of a frame front side portion and a frame rear side portion, and the load transmission portion is fixed at a joint portion where the frame front side portion and the frame rear side portion overlap with each other.

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