CN212890612U - Vehicle body lower structure - Google Patents

Abstract

The utility model provides a can realize the high-strength of crossbeam and realize the automobile body substructure of productivity's promotion. The vehicle body lower portion structure is provided with a rocker (15), a cross member (51), and a connecting bracket (52). The rocker is disposed on the vehicle width direction outer side of the floor panel (6) and extends in the vehicle body front-rear direction. The crossbeam disposes between the lower boundary beam. The connecting bracket is disposed at an end portion of the cross member on the outer side in the vehicle width direction, and connects the end portion of the cross member and the rocker. A reinforcing plate (27) joined to the connecting bracket and the inner wall section (31) in a superposed state is provided inside the rocker.

Description

Vehicle body lower structure

Technical Field

The utility model relates to a car body substructure.

Background

As a vehicle body lower portion structure, a structure is known in which a cross member is disposed between rocker members disposed on the outer side in the vehicle width direction of a floor panel. Some of such cross beams include those provided with deformation guides (hereinafter referred to as weak portions). According to this structure, for example, by deforming the fragile portion at the time of a side collision, it is possible to absorb an impact load (i.e., impact energy) input by the side collision (see, for example, patent document 1 (japanese patent application laid-open No. 2017-226396)).

Here, for the purpose of achieving weight reduction and high strength of a vehicle, for example, it is considered to use a high-tensile steel sheet for a cross member. However, it is difficult to secure a weld nugget when welding to the rocker in the cross member made of high-tensile steel plate. In this case, the beam needs to be softened, and the production process becomes complicated.

SUMMERY OF THE UTILITY MODEL

Problem to be solved by utility model

An object of the utility model is to provide a can realize the high strengthening of crossbeam and realize the automobile body substructure of productivity's promotion.

Means for solving the problems

(1) A vehicle body lower portion structure (for example, a vehicle body lower portion structure 2 according to an embodiment) according to an aspect of the present invention includes: a floor (for example, floor 6 of the embodiment) provided below a vehicle interior (for example, vehicle interior 23 of the embodiment); a pair of rocker beams (for example, rocker beams 15 in the embodiment) that are disposed on the vehicle-width-direction outer sides of the floor panel and extend in the vehicle-body front-rear direction; a cross member (for example, the cross member 51 of the embodiment) disposed between the rocker members and extending in the vehicle width direction; a connecting bracket (for example, a connecting bracket 52 according to the embodiment) that is joined to an outer end (for example, an outer end 51a according to the embodiment) of the cross member in the vehicle width direction and the rocker, and that connects the cross member and the rocker; and a reinforcement plate (for example, a reinforcement plate 27 of the embodiment) that is disposed on the opposite side of the connecting bracket with an opposing wall portion (for example, an inner wall portion 31 of the embodiment) of the rocker beam that opposes the connecting bracket in the vehicle width direction interposed therebetween, and that overlaps and is joined to the opposing wall portion and the connecting bracket when viewed in the vehicle width direction.

(2) In the vehicle body lower portion structure according to the aspect (1), the reinforcement plate may include: a gusset wall portion (e.g., a gusset wall portion 45 of the embodiment) that extends in the vehicle body longitudinal direction along the opposing wall portion of the rocker; and a gusset bottom portion (for example, a gusset bottom portion 46 of the embodiment) that extends outward in the vehicle width direction along a bottom portion (for example, an inner bottom portion 33 of the embodiment) of the rocker from a lower edge of a portion (for example, a rear portion 45a of the embodiment) of the gusset wall portion that avoids the connecting bracket in the vehicle body longitudinal direction.

(3) In the vehicle body lower portion structure according to the above aspect (1) or (2), the connecting bracket may have a lower strength than the cross member.

(4) In the vehicle body lower portion structure according to any one of the above (1) to (3), the cross member may include a weak portion (for example, the weak portion 61 in the embodiment) at a position near an outer end portion in the vehicle width direction.

(5) In the vehicle body lower portion structure according to the aspect (4), the fragile portion may be recessed upward.

(6) In the vehicle body lower portion structure according to any one of the above (1) to (5), the connecting bracket may include: a first flange (e.g., first flange 74 of an embodiment) that engages the opposing wall portions of the rocker; and a second flange (for example, a second flange 75 according to the embodiment) joined to a bottom portion (for example, an inner bottom portion 33 according to the embodiment) of the rocker that extends outward in the vehicle width direction from the lower edge of the opposing wall portion.

(7) In the vehicle body lower portion structure according to the above-described aspect (6), an outer end portion of the cross member in the vehicle width direction may be disposed with a gap (e.g., a gap S in an embodiment) in the vehicle width direction with respect to the rocker, and the connecting bracket may include: a cross member joint portion (for example, a cross member joint portion 71 in the embodiment) that is joined to an outer end portion of the cross member in the vehicle width direction; and a connecting portion (for example, a connecting portion 72 according to the embodiment) that extends outward in the vehicle width direction from the cross member joint portion and connects the first flange and the second flange.

Effect of the utility model

According to the aspect (1) described above, the connecting bracket is attached to the outer end portion of the cross member in the vehicle width direction, and the reinforcing plate is provided on the side opposite to the connecting bracket with the opposing wall portion of the rocker interposed therebetween. Therefore, the three members, i.e., the connecting bracket, the opposing wall portions of the rocker, and the reinforcing plate, are superposed and joined. Therefore, for example, even when the cross member is made high-strength by using a high-tensile steel plate (high-strength steel plate), the three members can be joined by welding or the like by overlapping the connecting bracket with the opposing wall portion of the rocker and the reinforcing plate without softening the cross member itself. Thus, the strengthened cross member can be connected to the opposing wall portions of the rocker and the reinforcement panel via the connecting bracket, and productivity can be improved.

Further, by overlapping and joining the three members, i.e., the opposing wall portions of the rocker, the reinforcing plate, and the connecting bracket, by welding or the like, it is possible to ensure rigidity against an impact load input due to, for example, a side collision.

Further, by connecting the cross member to the rocker via the connecting bracket, it is not necessary to accurately correspond the shape of the cross member to the rocker. Further, since the size of the connecting bracket may be changed according to the distance between the cross member and the rocker, the common cross member can be used for vehicles or the like having different distances between the rocker. Therefore, the degree of freedom in design can be improved.

According to the aspect (2), the strength and rigidity of the reinforcing plate can be improved by providing the reinforcing plate bottom portion. Further, the strength and rigidity of the rocker can be improved by the reinforcing plate by joining the reinforcing plate to the opposing wall portions and the bottom portion of the rocker.

Further, by providing the gusset bottom portion at a portion of the gusset that avoids the coupling bracket in the vehicle body longitudinal direction, the gusset bottom portion is not disposed at a portion corresponding to the coupling bracket. Therefore, for example, with respect to an impact load input due to a side collision, the strength and rigidity of the opposing wall portions of the rocker can be ensured by the reinforcing-plate wall portions, and the strength and rigidity of the opposing wall portions of the rocker can be appropriately suppressed. Thereby, the rocker is positively deformed so as to be crushed inward in the vehicle width direction. That is, since the rigidity of the rocker can be suppressed at the position corresponding to the cross member in the rocker, it is possible to suppress deformation of the rocker itself so as to rotate toward the cabin without being crushed by the impact load due to a side collision, and to absorb the impact energy well.

According to the aspect (3), the strength with which the connecting bracket can be joined to the rocker by welding can be selected by forming the connecting bracket from, for example, a plate material having a lower strength than the cross member. Here, a cross member having increased strength is joined to the connecting bracket. Therefore, by joining the connecting bracket to the rocker, the strength of the beam can be ensured by the beam having a high strength, and the joining strength between the beam and the rocker can be improved. This can improve productivity and reduce the weight of the vehicle body.

According to the aspect (4) described above, the impact load due to the side collision is transmitted to the fragile portion of the cross member through the connecting bracket, whereby the fragile portion of the cross member can be deformed by the impact load. This reduces the impact load transmitted to the region disposed inside the fragile portion. Therefore, the passenger space, the fuel tank, the battery, and the like in the vehicle compartment can be protected from the impact load.

According to the aspect (5) described above, since the fragile portion is recessed upward, a space below the fragile portion can be formed between the lower surface of the fragile portion and the lowermost surface of the vehicle body. Therefore, for example, an exhaust member, a fuel pipe, and the like below the floor can be disposed by using the space below the fragile portion. This improves the degree of freedom in the layout of the exhaust member, the fuel pipe, and the like, and reduces the vehicle height, thereby improving the appearance and quality of the vehicle.

According to the aspect (6), the first flange is joined to the opposing wall portion of the rocker in the vehicle width direction, and the second flange is joined to the bottom portion of the rocker in the vertical direction. That is, the first and second flanges are joined to the opposing wall portions and bottom portion of the rocker at different angles. This makes it possible to improve the joint strength (connection strength) between the rocker and the outer end of the cross member by the connecting bracket.

According to the aspect (7) described above, by forming the coupling portion in the coupling bracket, the coupling portion can be interposed between the beam joint portion and the first and second flanges. Further, an outer end portion of the cross member is disposed at the cross member joint portion. Therefore, the outer end of the cross member can be separated from the rocker by the length of the connecting portion. As a result, the coupling portion of the coupling bracket can be deformed so as to be crushed by the impact load due to the side collision, and the impact energy can be absorbed by the coupling bracket.

Drawings

Fig. 1 is a bottom view showing a vehicle body lower portion structure according to an embodiment of the present invention.

Fig. 2 is a sectional view taken along line II-II of fig. 1.

Fig. 3 is an enlarged view of a portion III of fig. 2.

Fig. 4 is a perspective view showing a rocker of the vehicle body lower portion structure of the embodiment.

Fig. 5 is a perspective view showing a center cross member unit of the vehicle body lower portion structure of the embodiment.

Fig. 6 is a sectional view taken along line VI-VI of fig. 5.

Fig. 7 is an exploded perspective view showing a center cross member unit of the vehicle body lower portion structure of the embodiment.

Description of the reference numerals

1 … vehicle

2 … vehicle body lower part structure

6 … floor

15 … rocker

23 … vehicle cabin

27 … reinforcing plate

31 … inner side wall part (opposite wall part)

33 … inner bottom (bottom)

45 … reinforced panel wall part

45a … rear part (part of the gusset wall part avoiding the connecting bracket)

46 … reinforcing the bottom of the board

51 … crossbeam

51a … outboard end

51b …

52 … connecting bracket

62 … concave part

71 … Beam Joint

72 … joint part

73 … engagement flange

74 … first flange

75 … second flange

S … gap

Detailed Description

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings used below, arrow FR indicates the front of the vehicle 1, arrow UP indicates the upper side of the vehicle 1, and arrow LH indicates the left side of the vehicle 1.

[ vehicle body lower Structure ]

Fig. 1 is a bottom view showing a vehicle body lower portion structure 2 of a vehicle 1.

As shown in fig. 1, a vehicle 1 includes a vehicle body lower portion structure 2 that constitutes a lower portion of a vehicle body. The vehicle body lower portion structure 2 includes a skeleton member 5, a floor panel 6, and a floor tunnel 7. The framework member 5 includes front side frames 11, outriggers 14, rocker beams 15, and a rear frame 16 on both sides of the vehicle 1. The framework member 5 includes a front cross member 17, a center cross member unit 20, and a rear cross member 21.

The vehicle body lower portion structure 2 is configured substantially bilaterally symmetrically. Therefore, the left and right constituent members are denoted by the same reference numerals, and the left constituent member is described in detail.

The front side frames 11 extend in the vehicle body longitudinal direction below a power plant (not shown) including a drive source, for example. An outrigger 14 extends from a rear end of the front side frame 11 outward in the vehicle width direction. A rocker 15 is connected to the rear end of the outrigger 14. The rocker 15 is disposed on the vehicle width direction outer side of the floor panel 6 and extends in the vehicle body front-rear direction. In other words, the floor panel 6 is provided between the rocker panels 15 on both sides of the vehicle 1. The floor 6 is provided below the vehicle interior 23 (see fig. 2), and forms a floor portion of the vehicle interior.

A floor tunnel 7 is provided at the center of the floor 6 in the vehicle width direction. The floor tunnel 7 extends in the vehicle body front-rear direction, and bulges upward toward the vehicle compartment 23 side.

A front cross member 17 is provided between the front end portions of the rocker 15. A center cross member unit 20 is provided between center portions of the rocker 15 in the vehicle body front-rear direction. Below the floor panel 6, a fuel tank F, a battery (not shown), and the like are disposed in a portion surrounded by the center cross member unit 20 and a rear cross member 21 (described later), for example.

The rocker 15 and the center cross member unit 20 will be described in detail later.

A rear frame 16 is connected to a rear end of the rocker 15. The rear frame 16 is disposed on the vehicle width direction outer side of the rear floor 22 and extends in the vehicle body front-rear direction. In other words, the rear floor 22 is provided between the rear frames 16 on both sides of the vehicle 1. The rear floor 22 forms a floor portion of a luggage room (not shown). A rear cross member 21 is bridged between the front end portions of the rear frame 16.

< lower boundary Beam >

Fig. 2 is a sectional view taken along line II-II of fig. 1. Fig. 3 is an enlarged view of a portion III of fig. 2.

As shown in fig. 2 and 3, the rocker 15 includes an inner panel 25, an outer panel 26, and a reinforcement panel 27.

The inner panel 25 has an inner side wall portion (opposing wall portion) 31, an inner ceiling portion 32, an inner bottom portion (bottom portion) 33, an inner upper flange 34, and an inner lower flange 35.

The inside wall portion 31 extends in the vehicle body longitudinal direction in a state of rising in the vertical direction. The inner roof portion 32 is bent so as to extend outward in the vehicle width direction from the upper edge of the inner wall portion 31. The inner bottom portion 33 is bent so as to extend outward in the vehicle width direction from the lower edge of the inner wall portion 31.

The inner upper flange 34 is bent so as to project upward from an outer edge (outer end edge in the vehicle width direction) of the inner top portion 32. The inner lower flange 35 is bent so as to extend downward from the outer edge of the inner bottom portion 33.

The inner panel 25 is formed in a top hat shape in cross section that is open to the outside in the vehicle width direction by the inner side wall portion 31, the inner roof portion 32, the inner bottom portion 33, the inner upper flange 34, and the inner lower flange 35.

The outer panel 26 is joined to the inner panel 25 from the outside in the vehicle width direction. The outer panel 26 has an outer side wall portion 37, an outer roof portion 38, an outer bottom portion 39, an outer upper flange 41, and an outer lower flange 42.

The outer wall portion 37 is disposed apart from the inner wall portion 31 outward in the vehicle width direction. The outer side wall portion 37 stands up in the vertical direction and extends in the vehicle body front-rear direction. The outer top portion 38 is bent so as to extend inward in the vehicle width direction from the upper edge of the outer side wall portion 37. The outer bottom portion 39 is bent so as to extend inward in the vehicle width direction from the lower edge of the outer wall portion 37.

The outer upper flange 41 is bent so as to extend upward from an inner edge (an inner end edge in the vehicle width direction) of the outer top portion 38. The outer lower flange 42 is bent so as to extend downward from the inner edge of the outer bottom 39.

The outer panel 26 is formed in a top hat shape in cross section that opens inward in the vehicle width direction by the outer side wall portion 37, the outer roof portion 38, the outer floor portion 39, the outer upper flange 41, and the outer lower flange 42.

The inner upper flange 34 and the outer upper flange 41 are joined in the vehicle width direction by, for example, spot welding. The inner lower flange 35 and the outer lower flange 42 are joined to each other in the vehicle width direction by spot welding, for example. The rocker 15 has a closed cross-section portion having a rectangular cross-section formed by the inner panel 25 and the outer panel 26, and ensures strength and rigidity.

Fig. 4 is a perspective view showing the inner panel 25 and the reinforcement panel 27 of the rocker 15. As shown in fig. 3 and 4, the reinforcing plate 27 is provided inside the closed cross-sectional portion of the rocker 15. The reinforcing plate 27 has a reinforcing plate wall portion 45 and a reinforcing plate bottom portion 46. The gusset wall portion 45 extends in the vehicle body longitudinal direction along the inner surface (the surface facing outward in the vehicle width direction) of the inner wall portion 31. The reinforcing plate wall portion 45 is joined to the inner surface of the inner wall portion 31 by spot welding, for example.

The gusset bottom portion 46 extends outward in the vehicle width direction along the inner bottom portion 33 from the lower edge of the rear portion 45a (a portion that avoids a connecting bracket 52, which will be described later, in a side view seen in the vehicle width direction) of the gusset wall portion 45. The rear portion 27a of the reinforcing plate 27 (a portion that avoids a coupling bracket 52 described later in a side view) is formed in a cross-sectional L shape by the reinforcing plate wall portion 45 and the reinforcing plate bottom portion 46. This improves the strength and rigidity of the reinforcing plate 27. The reinforcement plate bottom portion 46 is joined to the inner bottom portion 33 by spot welding, for example.

By joining the gusset wall portion 45 to the inner wall portion 31 and joining the gusset bottom portion 46 to the inner bottom portion 33 in this manner, the strength and rigidity of the inner panel 25 (i.e., the rocker 15) can be improved by the gusset 27.

Further, only the gusset wall portion 45 (excluding the gusset bottom portion 46) is formed in the front portion 27b of the gusset 27 (the portion where the coupling brackets 52 overlap in a side view). Therefore, for example, with respect to the impact load F1 input due to a side collision, the strength and rigidity of the inner bottom portion 33 can be appropriately suppressed while the strength and rigidity of the inner side wall portion 31 are ensured by the gusset wall portion 45. This can suppress deformation of the rocker 15 itself so as to pivot toward the vehicle interior 23 (see fig. 2) without being crushed by the impact load F1 due to a side collision. Therefore, the rocker 15 is deformed so as to crush inward in the vehicle width direction, and thus the impact energy can be absorbed satisfactorily.

< Central Beam Unit >

Fig. 5 is a perspective view showing the center beam unit 20. Fig. 6 is a sectional view taken along line VI-VI of fig. 5.

As shown in fig. 5 and 6, the center beam unit 20 includes a beam 51 and a connecting bracket 52.

The cross member 51 is disposed between the rocker members 15 and extends in the vehicle width direction (see also fig. 1). The cross member 51 has a cross member bottom 54, a cross member front wall portion 55, a cross member rear wall portion 56, a cross member front flange 57, and a cross member rear flange 58.

The beam bottom 54 is disposed substantially horizontally along the floor panel 6 in a state separated downward from the floor panel 6. The beam front wall portion 55 is bent so as to project upward (i.e., the floor 6) from the front edge of the beam bottom portion 54. The beam rear wall portion 56 is bent in such a manner as to project upward (i.e., the floor panel 6) from the rear edge of the beam bottom portion 54.

The cross member front flange 57 is bent so as to project from the upper edge of the cross member front wall portion 55 toward the vehicle body front side. The cross member rear flange 58 is bent so as to extend rearward of the vehicle body from the upper edge of the cross member rear wall portion 56.

The cross member 51 is formed in a top hat shape in cross section that opens upward, with a cross member bottom 54, a cross member front wall 55, a cross member rear wall 56, a cross member front flange 57, and a cross member rear flange 58. The cross member 51 is joined to the lower surface of the floor panel 6 by joining the cross member front flange 57 and the cross member rear flange 58 to the lower surface of the floor panel 6 by spot welding, for example. In the present embodiment, a gap S (see fig. 3) is provided in the vehicle width direction between the outer end 51a of the cross member 51 in the vehicle width direction and the inner panel 25 (inner wall portion 31). The gap S opens in the front-rear direction and downward direction of the vehicle body.

The cross member 51 forms a closed cross-section portion having a rectangular cross-section together with the floor panel 6. The cross member 51 is formed of a high-tensile steel plate (high-strength steel plate), and thus can be reduced in weight and increased in strength. That is, the cross member 51 is a member having high strength and rigidity.

The cross member 51 includes a weak portion 61 at a position 51b near the outer end 51a in the vehicle width direction and located inward in the vehicle width direction. Here, the vicinity position 51b of the cross member 51 refers to, for example, a position between the outer end 51a and a passenger's space in the vehicle compartment 23 in the vehicle width direction. Alternatively, the vicinity position 51b refers to a position between the outer end 51a, the fuel tank F, and the battery.

The fragile portion 61 has, for example, a recess 62 and a plurality of ribs 63. The concave portion 62 is formed in a curved shape so that the beam bottom portion 54 is recessed upward toward the floor 6. Each rib 63 is formed separately in the vehicle body front-rear direction. Each rib 63 extends in the vehicle width direction along the concave portion 62 in a curved shape.

By forming the plurality of ribs 63 in the recess 62 of the fragile portion 61, the strength and rigidity of the fragile portion 61 can be appropriately adjusted. Thus, for example, when an impact load F1 is input to the outer end 51a of the cross member 51 due to a side collision, the fragile portion 61 can be appropriately deformed to efficiently absorb the impact energy. The plurality of ribs 63 may not be formed in the recess 62 in the fragile portion 61.

By forming the fragile portion 61 so as to be recessed upward from the lowermost surface of the cross beam bottom portion 54, the lower space 65 of the fragile portion 61 can be ensured between the lowermost surface of the vehicle body and the lower surface of the fragile portion 61 (see also fig. 2). Therefore, for example, the exhaust member 67 (see fig. 2) and a fuel pipe (not shown) below the floor panel 6 can be disposed in the lower space 65 of the fragile portion 61. This can improve the degree of freedom in the layout of the exhaust member 67 and the fuel pipe, and reduce the height of the vehicle 1, thereby improving the appearance and quality of the vehicle 1.

Fig. 7 is an exploded perspective view showing a state in which the center beam unit 20 is exploded into the beam 51 and the coupling bracket 52. In fig. 7, boundaries of the beam joint portion 71, the joint portion 72, and the joint flange 73 are shown by imaginary lines for the sake of convenience in order to facilitate understanding of the structure of the joint bracket 52.

As shown in fig. 3, 6, and 7, the coupling bracket 52 is bridged between the outer end 51a of the cross member 51 and the inner panel 25. The coupling bracket 52 has a beam coupling portion 71, a coupling portion 72, and a coupling flange 73. The coupling bracket 52 is formed of a plate material having a lower strength (tensile strength) than the cross member 51.

The beam joint portion 71 is formed in a U-shaped cross section that opens upward along the outer surfaces of the beam bottom portion 54, the beam front wall portion 55, and the beam rear wall portion 56 in the outer end portion 51a of the beam 51. The beam joint portion 71 is joined by, for example, spot welding in a state of being disposed so as to cover the beam bottom portion 54, the beam front wall portion 55, and the beam rear wall portion 56 from below in the outer side end portion 51a of the beam 51. Thus, the beam joint 71 is disposed at the outer end 51a of the beam 51. The beam joint portion 71 may be joined to at least a part of the outer end portion 51a of the beam 51.

The connecting portion 72 is formed continuously outward in the vehicle width direction from the cross member joining portion 71. The connection portion 72 includes a connection bottom portion 72a continuous with the beam connection portion 71, a connection front wall portion 72b, and a connection rear wall portion 72 c. The connecting portion 72 is formed in a cross-sectional U shape that opens upward in the same manner as the cross member joining portion 71 by connecting the bottom portion 72a, the connecting front wall portion 72b, and the connecting rear wall portion 72 c. The beam joint portion 71 and the coupling portion 72 are formed in a U-shaped cross section, so that the strength and rigidity of the beam joint portion 71 and the coupling portion 72 (i.e., the coupling bracket 52) are ensured. The joining flange 73 is integrally formed on the vehicle width direction outer side of the connecting portion 72. That is, the beam joint portion 71 and the joint flange 73 are integrally connected by the connection portion 72.

The engagement flange 73 has a pair of first flanges 74, and a second flange 75. The pair of first flanges 74 extend from the coupling portion 72 toward both sides in the vehicle body longitudinal direction. Of the pair of first flanges 74, the front first flange 74 extends along the inner wall portion 31 from the outer edge of the coupling front wall portion 72b toward the front of the vehicle body. Further, of the pair of first flanges 74, the rear first flange 74 extends from the outer edge of the coupling rear wall portion 72c toward the rear of the vehicle body along the inner wall portion 31.

Here, the reinforcement panel wall portion 45 described above is disposed on the opposite side of the pair of first flanges 74 with the inner wall portion 31 interposed therebetween in the vehicle width direction with respect to the first flanges 74 (see also fig. 4). The pair of first flanges 74 are disposed so as to overlap the inner wall portion 31 and the gusset wall portion 45 in the vehicle width direction, and are joined together with the inner wall portion 31 and the gusset wall portion 45 by spot welding, for example. That is, the three members are joined with the inner wall portion 31 sandwiched between the pair of first flanges 74 and the reinforcing plate wall portion 45.

The second flange 75 extends from the connecting bottom portion 72a toward the outside in the vehicle width direction along the inner bottom portion 33. The second flange 75 is joined to the inner bottom portion 33 by spot welding from below, for example.

Here, the coupling bracket 52 is formed of a plate material having a lower strength (tensile strength) than the cross member 51. Therefore, the strength (for example, the strength without softening treatment) at which the linking bracket 52 and the rocker 15 can be joined by spot welding can be selected. The cross member 51 having increased strength is joined to the connecting bracket 52. By joining the connecting bracket 52 to the rocker 15, the strength of the cross member 51 can be ensured by the cross member 51 having increased strength, and the joining strength between the cross member 51 and the rocker 15 can be increased. This can improve productivity and reduce the weight of the vehicle body.

The coupling bracket 52 is provided with a pair of first flanges 74 joined to the inner wall portion 31 and a second flange 75 joined to the inner bottom portion 33. The inner wall portion 31 and the inner bottom portion 33 are formed in an L-shaped cross section. The pair of first flanges 74 are joined to the inner wall portion 31 in the vehicle width direction, and the second flanges 75 are joined to the inner bottom portion 33 in the vertical direction. Thus, the pair of first and second flanges 74, 75 are joined to the inner wall portion 31 and the inner bottom portion 33 at different angles. This can improve the joint strength (connection strength) between the rocker 15 and the outer end 51a of the cross member 51 by the connecting bracket 52.

Further, the joint strength between the rocker 15 and the outer end 51a of the cross member 51 is increased by the connecting bracket 52. This can prevent the connecting bracket 52 from being separated from the rocker 15 or the cross member 51 by the impact load F1 (see fig. 3) input by the side collision. Further, by forming the coupling portion 72 in the coupling bracket 52, the coupling portion 72 can be interposed between the beam joining portion 71 and the joining flange 73 (i.e., the pair of first and second flanges 74, 75). Therefore, the gap S between the outer end 51a of the cross member 51 and the inner wall 31 of the rocker 15 can be secured by the length of the connecting portion 72. As a result, the coupling portion 72 of the coupling bracket 52 can be deformed so as to be crushed by the impact load F1 caused by the side collision, and the impact energy can be absorbed by the coupling bracket 52.

Further, by increasing the joining strength between the rocker 15 and the outer end 51a of the cross member 51 by the connecting bracket 52, the impact load F1 caused by a side collision can be efficiently transmitted to the outer end 51a of the cross member 51 via the connecting bracket 52. This can reliably deform the fragile portion 61 formed at the position 51b near the cross member 51, and can absorb impact energy well.

As described above, the coupling bracket 52 is attached to the outer end 51a of the cross member 51. Further, a reinforcing plate 27 is provided inside the rocker 15 (inner wall portion 31). Therefore, the three members of the inner wall portion 31, the reinforcement plate wall portion 45, and the first flange 74 can be overlapped and joined by, for example, spot welding. Thus, for example, when the cross member 51 is strengthened by using a high-tensile steel plate, the cross member 51 can be connected to the inner wall portion 31 and the reinforcing plate wall portion 45 via the pair of first flanges 74 without being softened, and productivity can be improved.

Further, by overlapping and joining the three members, i.e., the inner wall portion 31, the reinforcement panel wall portion 45, and the first flange 74, it is possible to ensure the rigidity of the rocker 15 with respect to, for example, the impact load F1 input due to a side collision.

Further, by coupling the cross member 51 to the inner wall portion 31 via the coupling bracket 52, it is not necessary to accurately correspond the shape of the cross member 51 to the rocker 15. Further, since the size of the connecting bracket 52 may be changed according to the distance between the cross member 51 and the rocker 15, the common cross member 51 may be used for the vehicles 1 and the like having different distances between the rocker 15. Therefore, the degree of freedom in design can be improved.

Next, an example in which an impact load F1 due to a side collision is input to a position (a position overlapping in a side view) corresponding to the center cross member unit 20 in the rocker 15 in the vehicle body lower portion structure 2 of the present embodiment will be described based on fig. 2.

As shown in fig. 2, the rocker 15 has the gusset bottom 46 removed at a position corresponding to the attachment bracket 52. Therefore, the rocker 15 is actively deformed so as to be crushed inward in the vehicle width direction, and thus the impact energy can be favorably absorbed by the rocker 15. That is, since the rigidity of the rocker 15 can be suppressed at the position of the rocker 15 corresponding to the center cross member unit 20, the rocker 15 itself can be suppressed from deforming so as to pivot toward the cabin 23 without collapsing against the impact load F1 input to the rocker 15.

In this state, the excessive impact load F2 is transmitted to the coupling bracket 52 via the rocker 15. The outer end 51a of the cross member 51 is disposed (joined) to the cross member joint portion 71 of the connecting bracket 52, and the joint flange 73 is joined to the inner panel 25 of the rocker 15. Therefore, the outer end 51a of the cross member 51 is separated from the inner wall 31 of the inner panel 25 toward the inside in the vehicle width direction by the length of the connecting portion 72. Thereby, the connecting portion 72 is deformed so as to be crushed inward in the vehicle width direction by the impact load F2. This allows the coupling bracket 52 to absorb impact energy.

In this state, the excessive impact load F3 is transmitted to the cross member 51 through the connecting bracket 52. The impact load F3 transmitted to the cross member 51 is transmitted to the fragile portion 61 through the outer end portion 51a of the cross member 51. The fragile portion 61 is deformed so as to bend the fragile portion 61 upward by the impact load F3. This allows the weak portion 61 to absorb the impact energy.

Here, the fragile portion 61 is disposed outside the passenger space in the vehicle interior 23 in the vehicle width direction, outside the fuel tank F in the vehicle width direction, and outside the battery in the vehicle width direction. This allows the fragile portion 61 to deform outward in the vehicle width direction with respect to the passenger space, the fuel tank F, and the battery in the vehicle compartment 23. Thus, when the impact load F1 is input to the position corresponding to the coupling bracket 52 in the rocker 15 due to a side collision, the passenger space in the vehicle compartment 23, the fuel tank F, the battery, and the like can be protected from the impact load F1.

(other modification example)

The preferred embodiments of the present invention have been described above, but the present invention is not limited to these embodiments. The structure can be added, omitted, replaced, and modified without departing from the scope of the present invention. The present invention is not limited by the foregoing description, but is only limited by the accompanying claims.

For example, in the above-described embodiment, the configuration of the present invention is applied to the center cross member unit 20, but the present invention is not limited to this configuration. The structure of the present invention can be adopted for the central beam unit 20 and the front and rear beams.

In the above-described embodiment, the reinforcing-plate bottom portion 46 is disposed only at the portion of the reinforcing plate 27 that avoids the coupling bracket 52 in the vehicle body longitudinal direction, but the present invention is not limited to this configuration. The gusset bottom 46 may be provided over the entire range of the gusset wall 45 in the vehicle longitudinal direction, or may be provided only with the gusset wall 45.

In addition, the components in the above-described embodiments may be replaced with known components as appropriate without departing from the scope of the present invention, and the above-described modifications may be combined as appropriate.

Claims (7)

1. A vehicle body lower portion structure is characterized in that,

the vehicle body lower portion structure includes:

a floor panel provided below a vehicle cabin;

a pair of rocker beams disposed on the outer side of the floor in the vehicle width direction and extending in the vehicle body front-rear direction;

a cross member disposed between the rocker beams and extending in the vehicle width direction;

a connecting bracket that is joined to an outer end portion of the cross member in the vehicle width direction and the rocker member, and that connects the cross member and the rocker member; and

and a reinforcing plate that is disposed on the opposite side of the connecting bracket with an opposing wall portion of the rocker that opposes the connecting bracket in the vehicle width direction interposed therebetween, and that overlaps and is joined to the opposing wall portion and the connecting bracket when viewed in the vehicle width direction.

2. The vehicle body lower structure according to claim 1,

the reinforcing plate has:

a gusset wall portion that extends in a vehicle body front-rear direction along the opposing wall portion of the rocker; and the number of the first and second groups,

and a gusset bottom portion that extends outward in the vehicle width direction along a bottom portion of the rocker from a lower edge of a portion of the gusset wall portion that avoids the connecting bracket in the vehicle body longitudinal direction.

3. The vehicle body lower structure according to claim 1 or 2,

the link bracket is lower in strength than the cross member.

4. The vehicle body lower structure according to claim 1 or 2,

the cross member includes a weak portion at a position near an outer end portion in the vehicle width direction.

5. The vehicle body lower structure according to claim 4,

the weak portion is recessed upward.

6. The vehicle body lower structure according to claim 1 or 2,

the connecting bracket includes:

a first flange engaged with the opposing wall portions of the rocker; and

and a second flange joined to a bottom portion of the rocker that extends outward in the vehicle width direction from a lower edge of the opposing wall portion.

7. The vehicle body lower structure according to claim 6,

an outer end portion of the cross member in the vehicle width direction is disposed with a gap in the vehicle width direction with respect to the rocker,

the connecting bracket comprises:

a cross member joint portion that is joined to an outer end portion of the cross member in the vehicle width direction; and

and a connecting portion that extends outward in the vehicle width direction from the cross member joint portion and connects the first flange and the second flange.

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