JP6504067B2 - Substructure of vehicle body - Google Patents

Description

  The present invention relates to a lower structure of a vehicle body in which a front ladder portion supporting a front side of a floor panel of a vehicle and a rear ladder portion supporting a rear side of the floor panel are connected and fixed.

  As a lower structure of a vehicle body of this type, a ladder-like lower structure for supporting a floor panel of a vehicle is known (see Patent Document 1). The lower structure of the vehicle body includes left and right side frames extending in the longitudinal direction of the vehicle, and a cross member fixed in a bridging manner between the left and right side frames. The left and right side frames are members having a hat cross section corresponding to the side members of the present invention, and are fixed to the floor panel on the upper side thereof. In the event of a vehicle collision, excessive deformation of the passenger compartment on the floor panel can be minimized by receiving an impact at each side frame. An upper reinforcement with a U-shaped cross section is fixed on the upper side in each side frame so that each side frame is not deformed excessively by impact, and the upper reinforcement is disposed over the entire length of the side frame There is. Further, on the lower side in the side frame, a doubler having a U-shaped cross section corresponding to the lower reinforcement of the present invention is fixed. A closed cross section is formed in the side frame by the upper reinforcement and the doubler, and the side frame is structurally reinforced.

  The lower structure of the vehicle body described above has a length dimension that covers substantially the entire length of the floor panel, and is generally formed by connecting two ladder-like members. That is, in this type of lower structure, a member (front ladder portion) supporting the front side of the floor panel and a member (rear ladder portion) supporting the rear side of the floor panel are used. A lower structure is formed by connecting and fixing the rear of the front ladder and the front of the rear ladder. In the connection portion between the ladder portions, the ladder portions are arranged in an overlapping manner, and for example, the side frame of the front ladder portion and the side frame of the rear ladder portion are fitted and welded and fixed to each other.

Japanese Utility Model Publication No. 6-87152

  By the way, in the lower structure of the above-mentioned vehicle body, there may occur a place where the upper reinforcement is not disposed at the connecting portion of the two ladders, for the purpose of fitting the side frames together. For example, when the rear ladder portion is fitted to the front ladder portion from the upper side, the upper reinforcement is omitted at the connecting portion so that the upper reinforcement of the front ladder portion does not interfere. Moreover, since it was necessary to fasten both ladder parts in the connection part, the upper reinforcement of the rear ladder part could not be extended as it was. For this reason, in the conventional configuration, a location (a gap) where the upper reinforcement is not disposed is generated in the connection portion between the ladder portions, and the connection portion is a structural weak point in the lower structure. Then, when receiving an impact at the time of a vehicle collision with the left and right side frames, there is a possibility that a portion with sudden change of proof strength may be generated at the connecting portion of ladders (for example, the upper side serving as a compression field). . However, although upper reinforcement can be added to the connecting portion after the ladder portions are fitted, such a problem arises that the manufacturing process of the vehicle is increased (the assemblability at the time of manufacture is deteriorated). The present invention has been made in view of the above-described points, and the problem to be solved by the present invention is that the connecting portion between the ladder portions becomes a structural weak point without requiring the retrofit of the upper reinforcement. It is about avoiding as much as possible.

  As means for solving the above problems, the lower structure of the vehicle body according to the first aspect of the present invention includes a front rudder portion supporting a front side of a floor panel of the vehicle body and a rear rudder portion connected to the front rudder portion. And a rear ladder portion for supporting the The front rudder portion and the rear rudder portion both have left and right side members arranged at appropriate intervals in the vehicle width direction, and a cross member fixed in a bridging manner between the left and right side members.

  In the present invention, each side member of both the front rudder portion and the rear rudder portion has a hat cross section opened at the upper side, and an upper reinforcement having a U-shaped cross section disposed on the upper side in each side member, and each side And a U-shaped lower reinforcement located at the lower side in the member. The side members of the front ladder portion and the corresponding side members of the rear ladder portion are fitted together at the connecting portion of the front ladder portion and the rear ladder portion, and the outer side members and the inner side disposed outside by this fitting And the inner side members to be placed on each other are fixed to each other. In this type of configuration, it is desirable to avoid, as much as possible, that the connecting portion between the ladder sections becomes a structural weakness without requiring the addition of the upper reinforcement.

  Therefore, in the present invention, the first upper reinforcement provided on the outer side member penetrates inward from the fitting side end of the outer side member in the vehicle longitudinal direction so as not to interfere with the inner side member. The second upper reinforcement provided on the inner side member is disposed so as to project from the end on the fitting side in the vehicle longitudinal direction of the inner side member. The first upper reinforcement is provided with a piled portion which is lowered toward the lower side of the outer side member, and the second upper reinforcement is placed on the piled portion so as to be overlapped from the upper side It is done. Further, the second upper reinforcement is provided with a through portion through which the second upper reinforcement can be inserted in the thickness direction and the welding device can be inserted at a portion where the outer side member and the inner side member are fitted. It is done. In the present invention, by arranging the upper reinforcements one on top of the other while connecting the ladders (by eliminating the non-arranged portion of the upper reinforcement), it is possible to avoid the structural weakness of the connection part as much as possible. . Furthermore, by inserting the welding device from the penetration portion of the second upper reinforcement, the outer side member disposed outside and the inner side member disposed inside can be firmly fixed by welding. Then, by providing the penetrating portion in a portion where the outer side member and the inner side member are fitted, the weakening of the lower structure due to the formation of the penetrating portion can be suitably avoided.

  In the lower structure of a vehicle body according to a second aspect of the present invention, in the lower structure of the vehicle body according to the first aspect, the first upper reinforcement and the second upper reinforcement sandwich the upper joint at the connecting portion of the front rudder portion and the rear rudder portion. The first lower reinforcement provided in the outer side member and the second lower reinforcement provided in the inner side member are linearly arranged with the lower joint interposed therebetween. It is done. In the present invention, the position of the upper joint and the position of the lower joint are offset in the vehicle longitudinal direction. In the present invention, the connection portion between the ladders is structurally weak by disposing the upper joint formed between the upper reinforcements and the lower joint formed between the lower reinforcements in a shifted manner. Can be suitably avoided.

  A lower structure of a vehicle body according to a third aspect of the present invention is the lower structure of the vehicle body according to the first aspect or the second aspect, wherein the first upper reinforcement and the second upper reinforcement each have a bottom wall disposed on the lower side; And side walls projecting upward from the left and right of the bottom wall. In the overlapping portion, the side wall of the first upper reinforcement is lowered in a step-like manner toward the lower side. In addition, a dot-like welded portion, which is a fixing place with the outer side member, is provided on the side wall of the second upper reinforcement of the inner side member. In the present invention, the sidewall of the second upper reinforcement of the inner side member is securely fixed by the outer side member, for example, in a dot-like weld formed by spot welding. At this time, in the overlapping portion, the side wall of the first upper reinforcement is stepped down so that the side wall of the second upper reinforcement can be disposed at a proper position, and the welding portion can be more accurately provided.

  A lower structure of a vehicle body according to a fourth aspect of the present invention is the lower structure of the vehicle body according to any of the first to third aspects of the present invention, wherein the through portion is an elongated hole elongated in the vehicle longitudinal direction. In the present invention, it is possible to appropriately move the welding device in the longitudinal direction of the vehicle while inserting the welding device into the long hole-like penetrating portion, and for example, a plurality of welding portions can be formed smoothly.

  In the lower structure of a vehicle body according to the fifth invention, in the lower structure of the vehicle body according to any of the first invention to the fourth invention, at least a part of the inner edge of the through portion has a rib structure which is a bending deformation point of the inner edge itself. It is provided. In the present invention, by reinforcing the penetrating portion (relatively fragile portion) by the rib structure, it is possible to more preferably avoid that the connecting portion becomes a structural weak point.

  A lower structure of a vehicle body according to a sixth aspect of the present invention is the lower structure of the vehicle body according to the fifth aspect of the present invention, wherein the rib structure is provided at an end of the through portion in the longitudinal direction of the vehicle. In the present invention, the rib structure can suitably reinforce the appropriate position of the penetration portion (the position that is likely to be a structural weakness).

  According to the first aspect of the present invention, it is possible to avoid, as much as possible, that the connecting portion between the rudder parts becomes a structural weak point without requiring the addition of the upper reinforcement. Further, according to the second aspect of the invention, it is possible to preferably avoid that the connecting portion between the ladder portions becomes a structural weak point. Further, according to the third aspect of the present invention, it is possible to more preferably avoid that the connecting portion between the ladder portions becomes a structural weak point. According to the fourth aspect of the present invention, it is possible to avoid, as much as possible, that the ladder portions are strongly connected to each other and the connection portion is structurally weak. According to the fifth aspect of the present invention, it is possible to avoid, as much as possible, that the ladder portions are more strongly connected to each other and the connecting portion becomes a structural weak point. According to the sixth aspect of the present invention, it is possible to avoid, as much as possible, that the ladder portions are further firmly connected to each other and the connection portion becomes a structural weak point.

1 is a schematic side view of a vehicle. It is a perspective view which disassembles and shows a part of lower structure of a vehicle body. It is a perspective view which disassembles and shows a part of each ladder part in a connection part. It is a see-through | perspective perspective view of the rear of a front rudder part. It is a see-through | perspective perspective view of the front part of a rear rudder part. It is a perspective view which shows the connection part of the lower structure of a vehicle body. It is a see-through | perspective side view which shows the connection part of the lower structure of a vehicle body. It is a top view which shows the connection part of the lower structure of a vehicle body. FIG. 8 is a cross-sectional view of the lower structure corresponding to the cross section taken along line IX-IX of FIG. 7; FIG. 8 is a cross-sectional view of the lower structure corresponding to the cross section along line XX in FIG. 7; FIG. 8 is a cross-sectional view of the lower structure corresponding to the cross section taken along line XI-XI of FIG. 7; FIG. 8 is a cross-sectional view of the lower structure corresponding to the cross section along line XII-XII in FIG. 7; FIG. 8 is a cross-sectional view of the lower structure corresponding to the cross section taken along line XIII-XIII of FIG. 7;

  Hereinafter, modes for carrying out the present invention will be described with reference to FIGS. 1 to 13. In the drawings, for convenience, arrow lines indicating the longitudinal direction, the lateral direction, and the vertical direction of the vehicle are appropriately illustrated. In the present embodiment, the longitudinal direction, the lateral direction, and the vertical direction of each component in the lower structure are determined based on the state where the lower structure of the vehicle body is disposed in the vehicle.

  The vehicle 2 shown in FIG. 1 is provided with a floor panel 4 provided at the lower part of the passenger compartment and a lower structure 6 of the vehicle body for supporting the floor panel 4 from the back side. The lower structure 6 of the vehicle body is a ladder-like lower structure extending in the front-rear direction, and is configured by connecting a front ladder portion 10 and a rear ladder portion 20 described later. And each ladder part 10 (20) is provided with the side members 12R and 12L (inner side members 22R and 22L) of the outer side on either side mentioned later with reference to Drawing 2, and a plurality of cross members 14 (24). There is. In addition, in the connection portion JA of the front ladder portion 10 and the rear ladder portion 20, the ladder portions are arranged in an overlapping manner, and the corresponding side members of each ladder portion 10 (20) (12R and 22R, 12L and 22L) Are fastened and fixed in a fitted state.

  In the event of a vehicle collision, the left and right side members receive an impact to minimize excessive deformation of the passenger compartment on the floor panel 4. For this reason, referring to FIGS. 2 to 5, in order to prevent excessive deformation of the left and right outer side members 12R and 12L (inner side members 22R and 22L) due to impact, they are respectively described later, as described later. Upper reinforcement 31 (33) and lower reinforcement 32 (34) are provided in advance. In this type of configuration, the joint portion JA between the ladders tends to be a structural weak point due to the restriction when fitting the side members, etc., and in the event of a vehicle collision, there may be a site where the load resistance changes suddenly. I was concerned. Therefore, in the present embodiment, by arranging the reinforcements 31 to 34 skillfully as described later, it is decided to avoid, as much as possible, that the connection portion JA of the ladder portions becomes a structural weakness. . Each component will be described in detail below.

[Front ladder section]
The front ladder portion 10 is configured of a ladder-like member that supports the front side of the floor panel 4 with reference to FIG. 1. Referring to FIGS. 2 and 3, the front ladder portion 10 includes left and right outer side members 12R and 12L, a plurality of cross members 14, a bumper reinforcement 13, a first upper reinforcement 31, and a first reinforcement. Lower reinforcement 32 and an overlapping portion 40 described later. Here, referring to FIG. 2, the plurality of cross members 14 are each formed of a member having a hat cross section elongated in the vehicle width direction (left and right direction) (in FIG. The symbol 14 of is attached). In the front ladder portion 10, a plurality of cross members 14 are fixed in a bridging manner between the left and right outer side members 12R and 12L described later, and are arranged with an appropriate interval in the vehicle longitudinal direction. ing. Further, bumper reinforcements 13 are fixed to the front ends of the left and right outer side members 12R and 12L, and the bumper reinforcements 13 are members extending in the vehicle width direction, and the left and right ends thereof are bent backward.

  Then, with reference to FIG. 2, the left and right outer side members 12R and 12L are disposed at appropriate intervals on the left and right in the vehicle width direction, and are fixed to the back surface of the floor panel 4 of FIG. There is. Here, since the left and right outer side members 12R and 12L have substantially the same configuration, details of the outer side member 12R disposed on the right side of the vehicle will be described as an example. The outer side member 12R is formed of a member having a hat cross section elongated in the vehicle longitudinal direction, and referring to FIGS. 3 and 4, the bottom surface portion 12a, the side surface portions 12b and 12c, and the flange portion It has 12d and 12e. The bottom surface portion 12a is a wall disposed on the lower side to form a bottom of the outer side member 12R, and the side surface portions 12b and 12c are walls projecting upward from the left and right of the bottom surface portion 12a. Further, the flange portions 12d and 12e are portions formed by bending the upper end portions of the side surface portions 12b and 12c which are relatively long in the upper and lower directions, and facing the floor panel 4 It can be arranged. The outer side member 12R can be welded and fixed to the back surface of the floor panel 4 on the side of the flange portions 12d and 12e provided on the upper side with reference to FIG.

  Here, referring to FIGS. 4 and 6, the side member 12R on the outside of the front ladder portion 10 corresponds to the “outside side member to be disposed on the outside” in the present invention in a connection portion JA described later. Further, the rear end 12E of the outer side member 12R corresponds to the "end on the fitting side in the longitudinal direction of the vehicle" in the present invention. Therefore, the bottom surface portion 12a of the outer side member 12R is set to have a relatively large dimension in the vehicle width direction, and the corresponding inner side member 22R of the rear ladder portion 20 described later may be fitted therein. it can. A first upper reinforcement 31 and a first lower reinforcement 32 to be described later are fixed to the outer side member 12R by a method such as welding. By forming a closed cross section in the outer side member 12R as shown in FIG. 9 by these both reinforcements 31 and 32, the outer side member 12R is structurally reinforced and hardly deformed.

Upper Reinforce
The first upper reinforcement 31 is disposed on the upper side in the outer side member 12R and extends in the extending front-rear direction of the outer side member 12R with reference to FIGS. 3 and 4. The first upper reinforcement 31 is a member having a hat cross section which is shallower than the outer side member 12R, and is provided with a bottom wall 31a, side walls 31b and 31c, and a flange disposed to face the bottom portion 12a. It has sections 31d and 31e. The side walls 31b and 31c are walls projecting upward from the left and right of the bottom wall 31a, and are disposed to face the corresponding side portions 12b and 12c. In the first upper reinforcement 31, the side walls 31b and 31c and the bottom wall 31a are arranged in a U-shape in cross section. Further, the flange portions 31d and 31e are portions formed by bending the upper end portions of the side walls 31b and 31c outward, and are overlapped from above on the corresponding flange portions 12d and 12e of the outer side member 12R. .

  Then, with reference to FIG. 4, the first upper reinforcement 31 is previously fixed in a state of being fitted to the outer side member 12R from the upper side prior to the connection with the rear ladder portion 20 described later. In this state, since the first upper reinforcement 31 is relatively shallow, referring to FIGS. 7 and 9, the bottom wall 31a is slightly lower than the upper end of the outer side member 12R. They are arranged (the bottom wall 31a is arranged in the mezzanine). The left and right side walls 31b and 31c are appropriately welded and fixed to the corresponding side portions 12b and 12c of the outer side member 12R, and the flange portions 31d and 31e are appropriately welded and fixed to the flange portions 12d and 12e. (In FIG. 4, welds are marked with x, and only specific welds are marked W1 to W4). Further, as it is necessary to form a connecting portion JA with the rear ladder portion 20 shown in FIG. 6, the rear end 31E of the first upper reinforcement 31 is the rear end 12E of the outer side member 12R (fitting It is disposed forward of the side end). That is, the first upper reinforcement 31 enters the front, which is the inner side of the outer side member 12R, so as not to interfere with the inner side member 22R (upper front end 22UE) described later. And an inner side member 22R of a rear ladder portion 20 described later is fitted to the rear portion JA1 of the outer side member 12R from the rear portion (a piled portion 40 described later) of the first upper reinforcement 31 to the rear end 12E. Become.

Lower Reinforce
Further, referring to FIGS. 3 and 4, the first lower reinforcement 32 is disposed on the lower side in the outer side member 12R and extends in the front-rear direction. The first lower reinforcement 32 is also a U-shaped member in a bottom view with a shallow cross section, and has a bottom wall 32 a and side walls 32 b and 32 c. The first lower reinforcement 32 is also fastened and fixed in advance in a state of being fitted to the lower side of the outer side member 12R prior to connection with the rear ladder portion 20 described later. Further, since it is necessary to form a connection portion JA with the rear ladder portion 20 shown in FIG. 6, the rear end 32E of the first lower reinforcement 32 protrudes from the rear end 12E of the outer side member 12R with reference to FIG. Without it is placed in front of the vehicle. Furthermore, the rear end 32E of the first lower reinforcement 32 is disposed rearward of the rear end 31E of the first upper reinforcement 31 and is an inner side member 22R (lower front end 22LE) of the rear ladder portion 20 described later. It is extended to the position which does not interfere with.

[Overlay]
The overlapping portion 40 is a portion where a second upper reinforcement 33 of the rear ladder portion 20 described later is disposed to be overlapped from the upper side with reference to FIGS. 6, 7 and 10. In addition, the second upper reinforcement 33 may be arranged to be overlapped in a state in which a slight gap is provided between the second upper reinforcement 33 and the overlapping portion 40. It means that it may be piled up and placed in contact with 40. The overlapping portion 40 is a portion where the side walls 31 b and 31 c are lowered in a step-like manner toward the lower side at the rear of the first upper reinforcement 31. In the present embodiment, the side wall 31b, 31c of the first upper reinforcement 31 is formed with a stepped portion 41 which is lowered by one step on the rear side, and a rear end portion which is further lowered by one step than the stepped portion 41. Is the overlapping portion 40. The first upper reinforcement 31 is welded and fixed in advance to the outer side member 12R as described above. At this time, referring to FIG. 4, the side walls 31b and 31c are stepped in the overlapping portion 40, so that spot-shaped welded portions W1 and W1 are formed at appropriate positions of the side wall portions as the overlapping portion 40. W2 can be provided reliably. Similarly, dot-shaped welds W3 and W4 can be reliably provided at appropriate positions on the side wall portions of the step portion 41. Then, in a state where a second upper reinforcement 33 described later is placed on the stacking unit 40, referring to FIGS. 6 and 7, the first upper reinforcement 31 and the second upper reinforcement 33 described later are side It will be in the state arrange | positioned linearly in the front-back direction to which a member extends.

[Rear ladder section]
The rear ladder portion 20 is formed of a ladder-like member that supports the rear side of the floor panel 4 with reference to FIG. 1. Referring to FIGS. 2 and 3, the rear ladder portion 20 includes left and right inner side members 22R and 22L, a plurality of cross members 24, a second upper reinforcement 33, and a second lower reinforcement 34. , And a through portion 50 and a rib structure 60 which will be described later. Here, among the constituent members of the rear ladder portion 20, the constituent members having substantially the same basic configuration as the corresponding constituent members of the front ladder portion 10 will be given the reference numerals corresponding to the front ladder portion 10, etc. There is something to do. Each cross member 24 has substantially the same configuration as the cross member 14 of the front ladder portion 10, as shown in FIG. 2, and is fixed in a bridging manner between the left and right inner side members 22R and 22L. It is done.

  The left and right inner side members 22R and 22L also have substantially the same basic configuration as the corresponding members (12R and 12L) of the front ladder portion 10, and are arranged with appropriate intervals on the left and right in the vehicle width direction. It is set up. Here, since the left and right inner side members 22R and 22L have substantially the same configuration, details of the inner side member 22R disposed on the right side of the vehicle will be described as an example. The inner side member 22R is also made of a member having a hat cross section similarly to the outer side member 12R of the front ladder portion 10 with reference to FIGS. 3 and 5, and a bottom surface portion 22a and a side surface portion 22b. 22c and flange portions 22d and 22e. In the inner side member 22R, upper front ends 22UE of the side portions 22b and 22c project forward relative to the lower front end 22LE.

  Here, referring to FIGS. 5 and 6, the side member 22R on the inner side of the rear ladder portion 20 corresponds to the “inner side member disposed on the inner side” in the present invention in a connection portion JA described later. The upper front end 22UE of the inner side member 22R corresponds to "the end on the fitting side in the longitudinal direction of the vehicle" in the present invention. Therefore, the bottom surface 22a of the inner side member 22R is set to have a relatively small dimension in the vehicle width direction, and can be fitted into the outer side member 12R of the front ladder portion 10. Then, referring to FIG. 6, the front JA2 of the inner side member 22R is engaged with and connected to the rear JA1 of the outer side member 12R from the upper side to form a connection portion JA of both ladders. It becomes.

  The second upper reinforcement 33 has the same basic configuration as the first upper reinforcement 31 of the front rudder portion 10, as shown in FIGS. That is, the second upper reinforcement 33 is a member having a hat cross section which is shallow at the bottom, and has the bottom wall 33a, the side walls 33b and 33c, and the flanges 33d and 33e, as the first upper reinforcement 31. doing. The second lower reinforcement 34 also has the same basic configuration as the first lower reinforcement 32 of the front ladder portion 10, and has a bottom wall 34a and side walls 34b and 34c. Referring to FIG. 8, a substantially circular through hole H is provided on the front side of the bottom wall 33 a of the second upper reinforcement 33. Referring to FIGS. 6 and 8, a plurality of substantially circular through holes H are also provided in bottom wall 34a and left and right side walls 34b and 34c of second lower reinforcement 34, and a suitable distance in the front-rear direction is provided. It is arranged by. Each of the through holes H is a portion for welding and fixing the front rudder portion 10 and the rear rudder portion 20.

  The second upper reinforcement 33 and the second lower reinforcement 34 are also welded and fixed in advance in a state of being fitted to the inner side member 22R prior to connection with the front ladder portion 10 with reference to FIG. (In FIG. 5, welds are marked with x marks). In this state, since the second upper reinforcement 33 is relatively shallow, the bottom wall 33a of the second upper reinforcement 33 is made of the inner side member 22R, as shown in FIGS. 7 and 11. It is arranged slightly lower than the upper end (the bottom wall is arranged in the mezzanine). The second lower reinforcement 34 is disposed on the lower side in the inner side member 22R. Then, by forming a closed cross section in the inner side member 22R by these two reinforces 33, 34, the inner side member 22R is structurally reinforced and is less likely to be deformed. In the present embodiment, referring to FIG. 5, the front end 33E of the second upper reinforcement 33 protrudes from the upper front end 22UE (the end on the fitting side) of the inner side member 22R and protrudes forward in the vehicle There is. The front end 34E of the second lower reinforcement 34 is disposed behind the front end 33E of the second upper reinforcement 33 at substantially the same position as the lower front end 22LE of the side member 22R behind the vehicle and on the inner side.

[Penetration part]
The penetration part 50 is a site | part which penetrates the bottom wall 33a of the 2nd upper reinforcement 33 with reference to FIG.7 and FIG.8 in the thickness direction, and as shown in FIG. 13, the welding apparatus 70 can be inserted. The penetrating portion 50 is a long hole elongated in the front-rear direction in which the inner side member 22R extends, and has a length dimension such that the welding device 70 inserted as shown in FIG. There is. Further, referring to FIG. 7, penetrating portion 50 is a portion where outer side member 12R and inner side member 22R are fitted together (hereinafter referred to as fitting portion JA3) in a connection portion JA of both ladder portions described later. Provided). The through portion 50 may be accommodated in the fitting portion JA3, or may slightly protrude from the fitting portion JA3 in the vehicle longitudinal direction. In the present embodiment, most of the through portion 50 is provided in the fitting portion JA3, and the rear end side of the rear end 50E of the through portion 50 is the rear end of the fitting portion JA3 (reference numeral 12E in FIG. 7). Slightly out of the 7 and 8, under the penetrating portion 50, the inner and outer side members 12R and 22R are disposed overlapping each other in the fitting portion JA3, and the second lower reinforcement 34 is further provided. A through hole H of a part of is disposed. Then, as shown in FIG. 13, welds W7 to W18 described later shown in FIGS. 7 and 8 are provided by welding equipment 70 or the like inserted into the through portion 50, and the inner and outer side members 12R and 22R are welded and fixed. The Rukoto. Further, in order to save time and labor in the welding operation described later, in the present embodiment, the dimension in the front-rear direction of the penetrating portion 50 is set to a length that can cover the welded portions W7 to W18 described later.

[Rib structure]
Further, at least a part of the inner edge of the penetrating portion 50 is cranked toward the lower side and the inner side of the inner side member 22R with reference to FIG. 8 and FIG. It becomes. In the present embodiment, a rib structure 60 is provided at the rear end portion 50E of the penetrating portion 50 so as to be substantially U-shaped in a top view, and is preferably reinforced. The rear end portion 50E of the through portion 50 corresponds to the “end portion on the side away from the overlapping portion of the through portion in the vehicle longitudinal direction” in the present invention. Referring to FIGS. 7 and 8, rear end 50E of through portion 50 has a rear end side slightly protruding rearward from fitting portion JA3, and is a portion which is likely to be a structural weak point in lower structure 6 of the vehicle body. It is. By bending the rib structure 60 downward as described above, it is possible to make it difficult for foreign matter such as water to be accumulated in the portion.

[Formation work of substructure]
Referring to FIG. 2, left and right side members (12R, 22R, 12L, 22L) of the front ladder portion 10 and the rear ladder portion 20 are connected to form a lower structure 6 of the vehicle body. For example, referring to FIGS. 4 to 6, in the rear part JA1 of the outer side member 12R, while the front part JA2 of the inner side member 22R is fitted from the upper side, the connection part JA of these two ladder parts is formed. Here, with reference to FIG. 7, the connection portion JA of both ladder portions is a portion in which both ladder portions (including upper reinforcements) are disposed in an overlapping manner, and in the present embodiment, the second upper reinforcement 33 The portion from the front end 33E to the rear end 12E of the outer side member 12R. The fitting portion JA3 of the inner and outer side members 12R and 22R is a portion from the upper front end 22UE of the inner side member 22R to the rear end 12E of the outer side member 12R. In each of the ladder sections 10 and 20, the upper reinforcements 31 and 33 and the lower reinforcements 32 and 34 are fixed in advance to the corresponding side members 12R and 22R. Therefore, in the present embodiment, both the ladder sections 10 and 20 can be connected by the conventional number of manufacturing steps, and degradation of the assemblability at the time of manufacture can be suitably avoided. Then, referring to FIG. 7 and FIG. 8, the front ladder portion 10 and the rear ladder portion 20 are welded and fixed at an appropriate position of the connecting portion JA (note that in FIG. 7 and FIG. The marks W5 to W18 are attached only to the welds of In this type of configuration, it is desirable to arrange the respective reinforcements skillfully to avoid that the connecting portion JA of the ladder portions becomes a structural weakness as much as possible.

  In the present embodiment, referring to FIG. 7, outer side member 12R is configured such that first upper reinforcement 31 does not interfere with inner side member 22R (upper front end 22UE) at the connection portion JA between both ladders. It is disposed inward (forward) from the rear end 12E of the. Further, a second upper reinforcement 33 is disposed so as to project from the upper front end 22UE of the inner side member 22R. The rear end 31E of the first upper reinforcement 31 is provided with a piled portion 40 which is lowered toward the lower side. Then, the second upper reinforcement 33 protruding from the inner side member 22R is disposed to be overlapped from the upper side in the overlapping portion 40 while fitting the two ladder portions 10 and 20 together. In this manner, the first upper reinforcement 31 and the second upper reinforcement 33 are linearly arranged with the upper joint JP1 being a boundary between them. As described above, in the present embodiment, the connecting portions JA are structurally weak by arranging the upper reinforcements 31 and 33 to overlap with each other while connecting the ladder portions 10 and 20 with each other (eliminating non-arrangement places of reinforcements). Can be avoided as much as possible.

  Further, by fitting the two ladder sections 10 and 20, the first lower reinforcement 32 and the second lower reinforcement 34 are also arranged linearly with the lower joint JP2 being the boundary between them. Be done. At this time, the rear end 32E of the first lower reinforcement 32 is disposed rearward of the rear end 31E of the first upper reinforcement 31. Further, the front end 34E of the second lower reinforcement 34 is disposed rearward of the front end 33E of the second upper reinforcement 33. Therefore, the position of the lower joint JP2 formed on the lower side of the connecting portion JA is shifted to the rear of the vehicle with respect to the position of the upper joint JP1 formed on the upper side of the connecting portion JA. By disposing the upper joint JP1 and the lower joint JP2 which are likely to be structurally weak as described above, by shifting them in the vehicle longitudinal direction, it is possible to preferably avoid that the joint portion JA between the ladder portions becomes a structurally weak.

  Next, referring to FIGS. 7 and 8, the front ladder portion 10 and the rear ladder portion 20 are welded and fixed at an appropriate position of the connecting portion JA. For example, referring to FIG. 7, dot-like welds W5 and W6, which are fixing places with the outer side member 12R, are provided on the side wall 33b of the second upper reinforcement 33 superimposed on the overlapping portion 40. Fix it securely. At this time, in the overlapping portion 40, the side wall 32b is lowered downward in a step-like manner, so that the side wall 33b of the second upper reinforcement 33 can be disposed at an appropriate position above the overlapping portion 40. By welding, the dot-like welds W5 and W6 can be reliably provided.

  Further, the side surface portions 12b and 12c of the outer side member 12R and the side surface portions 22b and 22c of the inner side member 22R are welded and fixed (see weld portions W7 to W12 in FIG. 7). At this time, the second upper reinforcement 33 is provided with a through portion 50 into which the welding device 70 can be inserted at the fitting portion JA3. The side portions 22b and 22c of the inner side member 22R are exposed at the connection portion JA located below the through portion 50, and the second lower reinforcement 34 is further provided. The side surface parts 22b and 22c are exposed also from each through-hole H of this. Therefore, as shown in FIG. 13, welding parts W7 to W12 shown in FIG. 7 are formed from the penetration part 50 while inserting the welding device 70, and the side parts of the inner and outer side members 12R and 22R are formed by these welding parts W7 to W12. It can weld and fix each other. At this time, in the present embodiment, the welding device 70 can be appropriately moved in the longitudinal direction of the vehicle while inserting the welding device 70 into the long hole-like penetrating portion 50. For this reason, it is not necessary to carry in and out the welding apparatus 70 for every welding part, and several welding part W7-W12 can be formed smoothly. Further, the bottom surface 12a of the outer side member 12R and the bottom surface 22a of the inner side member 22R are welded and fixed (see welds W13 to W18 in FIG. 8). At this time, welds W14 to W18 can be formed through the respective through holes H provided in the bottom wall 34a of the second lower reinforcement 34 while inserting another welding device (not shown) into the through portion 50 in the same manner. Thus, in the present embodiment, the front ladder portion 10 and the rear ladder portion 20 can be firmly fixed at the connecting portion JA by the plurality of welding portions W7 to W18.

[The behavior of the lower structure at the time of a vehicle collision]
In the event of a vehicle collision, the left and right side members 12R, 12L (22R, 22L) receive an impact to minimize excessive deformation of the cabin on the floor panel 4. At this time, in the present embodiment, paying attention to the fact that the connection portion JA between the ladder portions is a structural weak point, referring to FIG. 7, the overlapping portion 40 of the first upper reinforcement 31 in this connection portion JA. The second upper reinforcement 33 is disposed to be overlapped from the upper side. By arranging the first upper reinforcement 31 and the second upper reinforcement 33 without gaps in this way, it becomes difficult to form a site where the proof stress changes suddenly in the connection part JA (for example, the upper side which becomes a compression field). It can be avoided as much as possible that the connecting portion JA between them becomes a structural weakness. Furthermore, in the present embodiment, the positions of the upper joint JP1 of the first upper reinforcement 31 and the second upper reinforcement 33 and the positions of the lower joint JP2 of the first lower reinforcement 32 and the second lower reinforcement 34 are It is offset in the longitudinal direction of the vehicle. By displacing the upper joint JP1 and the lower joint JP2 which are likely to be structural weaknesses in this way, it is possible to preferably avoid that the joint portion JA between the ladder portions becomes a structural weakness.

  Furthermore, in the present embodiment, the front rudder portion 10 and the rear rudder portion 20 are firmly fixed by the weld portions W5 to W18 provided at the connection portion JA. Then, by providing the penetrating portion 50 in the fitting portion JA3 in which the outer side member 12R and the inner side member 22R are engaged, the weakening of the lower structure due to the formation of the penetrating portion 50 can be suitably avoided. Furthermore, a rib structure 60 is provided and suitably reinforced in the penetration portion 50 of the rear ladder portion 20 (a portion which is likely to be a weak point). In particular, in the present embodiment, a rib structure 60 can be provided at the rear end portion 50E of the penetrating portion 50 which is likely to be a structural weak point to be suitably reinforced. Thus, in the present embodiment, an impact can be suitably received by the front ladder portion 10 and the rear ladder portion 20, and excessive deformation of the cabin on the floor panel 4 can be suitably suppressed.

  As described above, in the present embodiment, the upper reinforcements 31 and 33 are overlapped with each other while connecting the ladders 10 and 20 to each other (no location where the upper reinforcements are not disposed). Can be avoided as much as possible. In particular, in the present embodiment, the rudder portion is disposed by displacing the upper joint JP1 formed between the upper reinforcements 31 and 33 and the lower joint JP2 formed between the lower reinforcements 32 and 34. It can be suitably avoided that the connecting portion JA between them becomes a structural weakness.

  Further, by inserting the welding device 70 from the through portion 50 of the second upper reinforcement 33, the outer side member 12R and the inner side member 22R can be firmly fixed by welding. That is, the outer side member 12R and the inner side member 22R are firmly fixed by welding by the welded portions W5 to W18 provided in the connecting portion JA. These welds W <b> 5 to W <b> 18 can be suitably formed by inserting the welding device 70 from the penetration portion 50 of the second upper reinforcement 33. And by providing penetration part 50 in connection part JA (part in which ladder parts overlap and are arranged) of both ladder parts, weakening of the lower structure by formation of penetration part 50 is avoided suitably. it can. Further, in the present embodiment, the welding device 70 can be appropriately moved in the longitudinal direction of the vehicle while being inserted into the long hole-like penetrating portion 50, and for example, a plurality of welding portions W7 to W18 can be formed smoothly. Further, in the present embodiment, by reinforcing the penetrating portion 50 (relatively fragile portion) by the rib structure 60, it is possible to more preferably avoid that the connecting portion JA becomes a structural weak point. In particular, the rib structure 60 can suitably reinforce the rear end portion 50E of the through portion 50 (a portion which tends to be a structural weak point). Further, in the present embodiment, the second upper reinforcement 33 is securely fixed to the outer side member 12R at the dot-like welds W5 and W6. At this time, in the overlapping portion 40, the side walls 31b and 31c of the first upper reinforcement 31 are lowered downward in a step-like manner, whereby the side walls 33b and 33c of the second upper reinforcement 33 are disposed at appropriate positions. Thus, the welds W5 and W6 can be more accurately provided. For this reason, according to the present embodiment, it is possible to avoid, as much as possible, that the connecting portion between the rudder parts becomes a structural weak point without requiring the addition of the upper reinforcement.

  The lower structure of the vehicle body of the present embodiment is not limited to the above-described embodiment, and various other embodiments may be taken. For example, in the present embodiment, the configuration in which the rear ladder unit 20 is fitted in the front ladder unit 10 has been described. Conversely, the front ladder portion 10 can be fitted into the rear ladder portion 20. In this case, the configurations of the front ladder portion 10 and the rear ladder portion 20 are appropriately interchanged. The basic configurations (shape, dimensions, number of cross members, etc.) of the front ladder portion and the rear ladder portion can be changed as appropriate. The lower structure of the vehicle body may be disposed linearly in the longitudinal direction of the vehicle, or may be disposed in a slightly inclined state in the lateral direction.

  Moreover, although the structure (a shape, a dimension, a formation position etc.) of the stacking part 40 was illustrated in this embodiment, it is not the meaning which limits the structure of the part. For example, the overlapping portion may be disposed so as to overlap and arrange the second upper reinforcement, and the side wall of the first upper reinforcement may be gradually inclined downward toward the rear. In the overlapping portion, the side wall of the first upper reinforcement can be omitted. The configuration (shape, dimensions, formation position, etc.) of the through portion 50 can also be changed as appropriate. For example, a plurality of through portions can be formed in the second upper reinforcement, and the opening shape of each through portion is also a welding device As long as it can insert, it can be set as the shape (for example, notch shape) different from long hole shape. In addition, when making a penetration part into a long hole shape, it is desirable to set the length dimension to the dimension which can cover an adjacent welding part at least. And a rib structure can also be formed in the suitable position of a penetration part, and can also be provided in the inner perimeter whole circumference of a penetration part. This rib structure can be formed, for example, by bending the inner edge of the penetrating portion in the vertical direction, or can be formed by curving it in a roll shape. Also, a flat rib structure can be retrofitted to the inner edge of the through portion.

  In addition, the configuration (shape, dimensions, arrangement position, welding method, etc.) of each side member and each reinforcement can be appropriately changed. And each side member and each reinforcement should be fixed to each other at appropriate positions by dot-shaped welds formed by a technique such as spot welding, and also by linear welds formed by a technique such as arc welding. Can. Further, in the present embodiment, an example is described in which the position of the upper joint JP1 and the position of the lower joint JP2 are shifted in the vehicle longitudinal direction, but these joints can be provided at the same position in the vehicle longitudinal direction.

2 Vehicle 4 Floor panel 6 Lower structure of vehicle body 10 Front rudder part 12R, 12L Outer side member 12E Rear end of outer side member (the end on the fitting side of the outer side member)
13 bumper reinforcement 14 front ladder cross member 20 rear ladder 22R, 22L inner side member 22 UE upper front end of inner side member (end of fitting side of inner side member)
24 cross member 31 of rear ladder portion first upper reinforcement 31a first upper reinforcement bottom wall 31b, 31c first upper reinforcement side wall 31d, 31e first upper reinforcement flange 32 first lower reinforcement 32a First lower reinforcement bottom wall 32b, 32c First lower reinforcement sidewall 33 Second upper reinforcement 33a Second upper reinforcement bottom wall 33b, 33c Second upper reinforcement sidewall 33d, 33e second Bottom reinforcement flange part 34 second lower reinforcement 34a second lower reinforcement bottom wall 34b, 34c second lower reinforcement side wall 40 overlapping part 50 penetration part 50E rear end of penetration part (vehicle End of the through portion away from the overlapping portion in the front-rear direction )
60 rib structure (inner edge of penetration)
70 Welding equipment JA Connecting part between ladders JA3 Fitting part (part where outer side member and inner side member are fitted)
JP1 Upper joint JP2 Lower joint W1 to W4, W7 to W18 Welds W5, W6 Dot welds

Claims (6)

A front rudder portion supporting a front side of a floor panel of a vehicle body, and a rear rudder portion connected to the front rudder portion to support a rear side of the floor panel, and the front rudder portion and the rear rudder portion Both have left and right side members arranged at appropriate intervals in the vehicle width direction, and a cross member fixed in a bridging manner between the left and right side members,
Each of the side members of both the front ladder portion and the rear ladder portion has a hat cross section opened upward, and has an upper reinforcement with a U-shaped cross section disposed on the upper side in each side member, and in each side member Lower U-shaped lower reinforcement located at the lower side of the
Each side member of the front ladder portion and a corresponding side member of the rear ladder portion are fitted at the connection portion of the front ladder portion and the rear ladder portion, and the outer side disposed outside by this fitting In the undercarriage of a vehicle body in which the members and the inner side members arranged inside are fixed to one another,
The first upper reinforcement provided on the outer side member is inward of the fitting-side end of the outer side member in the vehicle longitudinal direction so as not to interfere with the inner side member. A second upper reinforcement provided on the inner side member is disposed so as to project from an end on the fitting side in the vehicle longitudinal direction of the inner side member, while being disposed.
The first upper reinforcement is provided with a piled portion lowered toward the lower side of the outer side member, and the second upper reinforcement is overlapped on the piled portion from the upper side Are arranged and
In the second upper reinforcement, the second upper reinforcement is penetrated in the thickness direction at a portion where the outer side member and the inner side member are fitted, and the welding device can be inserted The lower structure of the vehicle body where the part is provided. The first upper reinforcement and the second upper reinforcement are linearly arranged across the upper joint at the connecting portion of the front ladder portion and the rear ladder portion, and are provided on the outer side member A first lower reinforcement and a second lower reinforcement provided on the inner side member are linearly arranged across the lower joint,
The lower structure of a vehicle body according to claim 1, wherein the position of the upper joint and the position of the lower joint are shifted in the longitudinal direction of the vehicle. Each of the first upper reinforcement and the second upper reinforcement has a bottom wall disposed on the lower side, and a side wall projecting upward from the left and right sides of the bottom wall,
In the overlapping portion, the side wall of the first upper reinforcement is lowered in a step-like manner toward the lower side,
The lower portion of the vehicle body according to claim 1 or 2, wherein a dot-like welded portion which is a fixing place with the outer side member is provided on the side wall of the second upper reinforcement of the inner side member. Construction.   The lower structure of a vehicle body according to any one of claims 1 to 3, wherein the penetrating portion is an elongated hole elongated in the vehicle longitudinal direction.   The lower structure of the vehicle body according to any one of claims 1 to 4, wherein a rib structure which is a bending deformation point of the inner edge itself is provided on at least a part of the inner edge of the penetrating portion. The lower structure of a vehicle body according to claim 5, wherein the rib structure is provided at an end of the through portion on the side away from the overlapping portion in the vehicle longitudinal direction.

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