JP2007131148A - Vehicle body lower part structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a vehicle body structure capable of ensuring compatibility between improvement of productivity and maintenance of collision performance in a frontal collision. <P>SOLUTION: A front side member rear reinforcement 36 is fitted in the cross section of a front side member rear 34 having a hat-shaped cross section, and a floor upper member 42 is disposed at the position overlapping with a front side member rear 34 in the plan view on a front floor panel 32. Since the rear end part 42D of the floor upper member 42 is disposed at the front side of a first cross member 26, it is enough to only seal the floor upper member 42, and sealing of the first cross member 26 can be abolished. Therefore, the improvement of productivity is attained. Moreover, since the rear end part 36D of the front side member rear reinforcement 36 is extended to the position overlapping with the first cross member 26 in the plan view, bending yield strength of the front side member rear 34 in the front collision can be ensured. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a vehicle body lower structure that takes into account productivity resulting from a seal and a collision performance at the time of a frontal collision.

In the following Patent Document 1, a floor side member having a cross-sectional hat shape extending in the vehicle front-rear direction is joined to the upper surface of the floor panel, and a cross-sectional hat extending along the vehicle width direction so as to straddle the floor side member. A configuration for joining shaped cross members is disclosed.
Japanese Patent Laid-Open No. 9-24863

  However, in the case of the above prior art, in order to seal the vehicle interior from the outside of the vehicle interior, it is not only necessary to seal the entire circumference of the flange, which is the coupling surface of the floor side member, but also joined across the floor side member. Therefore, it is necessary to seal the entire circumference of the flange of the cross member.

  As one of the measures for solving this problem, it is conceivable to eliminate the seal of the cross member by cutting the floor side member before crossing the cross member. However, in that case, the rear end portion (that is, the front side of the cross member) that becomes the end of the floor side member becomes the weakened portion with respect to the vertical bending input that acts on the floor side member at the time of a frontal collision, and the deformation start point There is a possibility.

  In view of the above facts, an object of the present invention is to obtain a vehicle body lower structure capable of achieving both improvement in productivity and maintenance of collision performance during a frontal collision.

  The vehicle body lower part structure according to the first aspect of the present invention is formed in a cross-sectional hat shape, joined to the lower surface of the vehicle body floor and extended along the vehicle front-rear direction, and formed in a cross-sectional hat shape. A cross member joined to the upper surface of the vehicle body floor and extending in the vehicle width direction so as to intersect the front side member in plan view, and disposed in a cross section of the front side member and extending in the vehicle longitudinal direction. A vehicle body lower structure having a reinforcing member that is present and a reinforcing member that is formed in a cross-sectional hat shape and is joined to a position overlapping a front side member in a plan view on the upper surface of the vehicle body floor and extends in the vehicle front-rear direction. The reinforcing member is terminated at a front position of the cross member, and a rear end portion of the reinforcing member is seen in plan view in the cross member. Was extended to the position to or more vehicle rear side overlap, it is characterized by.

  According to a second aspect of the present invention, in the vehicle body lower structure according to the first aspect, the reinforcing member has a hat shape in cross section and is fitted inside the cross section of the front side member, and has a flange portion so as to sandwich the ridgeline. And the side wall is provided with a connecting point with the front side member.

  According to a third aspect of the present invention, in the vehicle body lower structure according to the second aspect, the bottom wall portion of the reinforcing member is separated from the bottom wall portion of the front side member and is not coupled. .

  According to a fourth aspect of the present invention, in the underbody structure according to any one of the first to third aspects, the flange portion of the reinforcing member has notches at a plurality of locations along a longitudinal direction thereof. The flange portion of the reinforcing member, the vehicle body floor, and the flange portion of the front side member are joined at the position where the notch portion is formed, and at the position where the notch portion is not formed, the reinforcing member The flange part and the flange part of a front side member are couple | bonded, It is characterized by the above-mentioned.

  According to the first aspect of the present invention, since the end position of the reinforcing member joined to the position overlapping the front side member on the upper surface of the vehicle body floor and extending along the vehicle front-rear direction is set to the front position of the cross member. The member and the cross member are separated from each other. Therefore, it is sufficient to seal only the peripheral edge of the reinforcing member, and the seal of the peripheral edge of the cross member can be eliminated. For this reason, productivity is improved.

  On the other hand, if the end of the reinforcing member is simply set at the front position of the cross member, the end of the reinforcing member becomes a sudden stiffness change part at the time of a frontal collision, and the bending strength decreases. However, in the present invention, the rear end portion of the reinforcing member arranged in the cross section of the front side member is extended to the vehicle rear side to a position where it overlaps with the cross member in a plan view or more, so A sudden stiffness change portion is not formed. Therefore, the front side member can sufficiently transmit the collision load at the time of frontal collision, and the collision performance is also ensured.

  According to the second aspect of the present invention, the cross-sectional shape of the reinforcing member is a hat shape, and the flange portion and the side wall portion are sandwiched with the ridgeline sandwiched in the cross-section of the front side member. Since the coupling point with the front side member is set, the ridgeline can be effectively reinforced. Depending on whether the ridgeline buckles or not, the bending strength of the front side member at the time of frontal collision also changes, so for example, the collision performance is better than that where the coupling point of the front side member is set on the flange and the bottom wall. Be improved.

  According to the third aspect of the present invention, since the bottom wall portion of the reinforcing member is separated from the bottom wall portion of the front side member and is not coupled, it is easy to align the reinforcing member with the front side member. In other words, if the bottom wall part of the reinforcing member is brought into contact with the bottom wall part of the front side member, the bottom wall parts interfere with each other even if a coupling point is set between the flange part and the side wall part. However, if the bottom wall portion of the reinforcing member is separated from the bottom wall portion of the front side member as in the present invention, the productivity is kept good.

  According to the fourth aspect of the present invention, the flange portion of the reinforcing member has notches formed at a plurality of locations along the longitudinal direction, and the flange portion of the reinforcing member is formed at the position where the notches are formed. Since the three parts of the vehicle body floor and the flange portion of the front side member are joined and the two parts of the flange portion of the reinforcing member and the flange portion of the front side member are joined at a position where the notch portion is not formed. The reliability (quality) for welding when joining by spot welding can be ensured. That is, as the overlap of the plates, there are a total of four pieces including the flange portion of the reinforcing member, the vehicle body floor, the flange portion of the reinforcing member, and the flange of the front side member from the top. Although it depends on the plate thickness, it is generally difficult to spot weld four plates at the same time while ensuring reliability for welding, but by forming a notch part, Since spot welding can be performed separately for two-layer spot welded portions, it is possible to connect four members while maintaining good spot welding reliability.

  As described above, the vehicle body lower part structure according to the first aspect of the present invention has an excellent effect that both improvement in productivity and maintenance of the collision performance at the time of frontal collision can be achieved.

  The vehicle body lower part structure according to the second aspect of the present invention has an excellent effect that the collision performance at the time of a frontal collision can be effectively improved.

  The vehicle body lower structure according to the third aspect of the present invention has an excellent effect that productivity can be improved.

  The vehicle body lower structure according to the present invention described in claim 4 can improve productivity because it is possible to connect four members as a whole by spot welding, and quality can be easily secured. It has an excellent effect that the reliability of the collision performance can be improved.

  (overall structure)

  Hereinafter, an embodiment of a lower body structure according to the present invention will be described with reference to FIGS. It should be noted that an arrow FR appropriately shown in these drawings indicates a vehicle front side, an arrow UP indicates a vehicle upper side, an arrow IN indicates a vehicle width direction inner side, and an arrow OUT indicates a vehicle width direction outer side. Is shown.

  FIG. 4 is a plan view showing a skeleton of the vehicle body lower structure according to the present embodiment. As shown in this figure, the vehicle body lower skeleton 10 includes a front floor portion 12 and a rear underbody portion 14. A total of six vehicle body frame members are arranged on the front floor portion 12 along the vehicle front-rear direction, and the load is transmitted by the six vehicle body frame members to the front-rear direction input load at the time of a frontal collision (input load). Is flown to the vehicle rear side using six vehicle body skeleton members).

  Specifically, a pair of left and right floor side members (rocker inner panels) 16 extending along the vehicle front-rear direction are disposed on both sides of the front floor portion 12. Further, on the inner side of the floor side member 16 in the front floor portion 12, a pair of left and right front side members 18 extending along the vehicle front-rear direction and obliquely extending (curving) outward in the vehicle width direction from the middle to the rear portion. Has been placed. Further, a pair of left and right tunnel under reinforcements 20 that are rounded toward the bottom from the vehicle rear side toward the vehicle front side are disposed inside the front side member 18 in the front floor portion 12.

  The front end portion of the tunnel under reinforcement 20 is welded to the inner side surface of the intermediate portion of the front side member 18 (the portion that has started to enter the region of the front floor portion 12). Further, the rear end portion of the tunnel under reinforcement 20 is welded to the front surface of the third cross member 22 (front floor cross member No. 3) disposed along the vehicle width direction between the rear end portions of the floor side member 16. ing. Further, the rear end portion of the front side member 18 is divided into two parts along the vehicle width direction between the longitudinal intermediate portions of the left and right floor side members 16 (front floor cross member No. 2). It is welded to the front of 2). The outer end portion of the second cross member 24 is welded to the inner side surface of the intermediate portion in the longitudinal direction of the floor side member 16, and the inner end portion is welded to the outer side surface of the tunnel under reinforcement 20. . Further, a pair of left and right first cross members (front floor cross member No. 1) 26 arranged in parallel with the pair of left and right second cross members 24 is disposed on the front side of the front side member 18. It intersects with the rear part of the round in plan view. Further, a cross member 27 extending along the vehicle width direction is disposed between the front end portions of the pair of left and right front side members 18.

  On the other hand, a pair of left and right rear underside members 28 also extend in the vehicle front-rear direction on the rear underbody portion 14 side. The front end portions of these rear underside members 28 are rounded so as to spread toward the outside in the vehicle width direction and are welded to the inner side surface of the rear end portion of the floor side member 16. A plurality of rear cross members 30 are disposed between the rear underside members 28 with the vehicle width direction as a longitudinal direction.

  (Main part configuration)

  Next, the main part of this embodiment and its peripheral structure will be described.

  FIG. 1 shows a connecting portion (A in FIG. 4) between a front side member rear 34 and a first cross member (front floor cross member No. 1) 26 constituting the rear portion of the front side member 18 according to the main part of the present embodiment. The structure of the section indicated by the arrow) is shown enlarged. FIG. 2 shows an enlarged perspective view of the connecting portion as seen from the vehicle rear side.

  As shown in these drawings, the front side member rear 34 has a hat shape in cross section, and includes a bottom wall portion 34A, a pair of left and right side wall portions 34B, and a pair of left and right flange portions 34C.

  A front side member rear reinforcement 36 as a reinforcing member having a hat shape in cross section is fitted inside the cross section of the front side member rear 34. As with the front side member rear 34, the front side member rear reinforcement 36 also includes a bottom wall portion 36A, a pair of left and right side wall portions 36B, and a pair of left and right flange portions 36C. However, as shown in FIG. 3, the height of the side wall portion 36B of the front side member rear reinforcement 36 is set lower than the height of the side wall portion 34B of the front side member rear 34. For this reason, the former bottom wall portion 36A is disposed at a position separated from the latter bottom wall portion 34A (arranged in a floating state), and a predetermined gap 38 is formed between them. . Further, as shown in FIG. 1, the flange portion 36 </ b> C of the front side member rear reinforcement 36 is formed in a waveform in a plan view. That is, the notches 40 are formed in the flange portion 36C at predetermined intervals along the longitudinal direction.

  The front side member rear reinforcement 36 having the above-described configuration is coupled to the front floor panel 32 by being spot-welded in a state where both the flange portions 36C and 34C are overlapped with each other while being fitted inside the cross section of the front side member rear 34. It has been previously sub-assembled.

  On the other hand, a floor upper member 42 as a reinforcing member is disposed along the vehicle front-rear direction at a position overlapping the front side member rear 34 in plan view on the front floor panel 32. The floor upper member 42 has a hat shape in cross section, and includes a top wall portion 42A, a pair of left and right side wall portions 42B, and a pair of left and right flange portions 42C. The flange portion 42C is arranged at a position where it overlaps with the flange portion 34C of the front side member rear 34 in a plan view, and at the position where the notch 40 of the flange portion 36C of the front side member rear reinforcement 36 is formed, the floor upper member 42 The flange portion 42C, the front floor panel 32, and the flange portion 34C of the front side member rear 34 are joined by spot welding (see the circled mark in FIG. 1) in a three-layered state. Further, at a position where the notch 40 of the flange portion 36C of the front side member rear reinforcement 36 is not formed, spot welding (a cross mark in FIG. 1) is performed with the flange portion 42C of the floor upper member 42 and the front floor panel 32 being overlapped. Reference).

  Furthermore, the rear end portion 42 </ b> D (that is, the terminal end) of the floor upper member 42 described above is located on the front side of the flange portion 26 </ b> A of the first cross member 26. That is, the floor upper member 42 and the first cross member 26 are arranged so as not to overlap each other in plan view.

  On the other hand, the rear end portion 36D of the front side member rear reinforcement 36 is extended to a position overlapping the first cross member 26 in plan view.

  Further, as shown in FIG. 3, the front side member rear reinforcement is formed at two locations of the side wall portion 36B and the flange portion 36C so as to sandwich the ridge 44 which is a bent portion of the side wall portion 36B of the front side member rear reinforcement 36 and the flange portion 36C. An inner coupling point 46 and an outer coupling point 48 by spot welding are respectively set on the side wall portion 34B and the flange portion 34C.

  (Operation and effect of this embodiment)

  Next, the operation and effect of this embodiment will be described.

  First, according to the vehicle body lower part structure according to the present embodiment, the rear of the floor upper member 42 that is joined to a position overlapping the front side member rear 34 on the upper surface of the front floor panel 32 in plan view and extends along the vehicle front-rear direction. Since the position of the end 42D is set to the front position of the first cross member 26 (a position that does not overlap in plan view), the floor upper member 42 and the first cross member 26 are substantially separated from each other. Therefore, it is only necessary to seal only the peripheral portion (flange portion 42C) of the floor upper member 42, and the seal of the peripheral portion (flange portion 26A) of the first cross member 26 can be eliminated. For this reason, productivity is improved (at the same time, cost reduction is also achieved).

  On the other hand, if the rear end portion 42D of the floor upper member 42 is simply set at the front position of the first cross member 26, the end of the floor upper member 42 becomes a rigid sudden change portion at the time of a frontal collision, and the bending strength is increased. descend. However, in the vehicle body lower part structure according to the present embodiment, the rear end portion 36D of the front side member rear reinforcement 36 disposed in the cross section of the front side member rear 34 is moved to the vehicle rear side to a position overlapping the first cross member 26 in a plan view. Since the extension is made, a rigid sudden change portion is not formed in front of the first cross member 26. Therefore, the front side member rear 34 can sufficiently transmit the collision load at the time of the frontal collision, and the collision performance is also ensured.

  As a result, according to the vehicle body lower part structure relating to the present embodiment, it is possible to achieve both improvement in productivity and maintenance of the collision performance at the time of frontal collision.

  The cross-sectional shape of the front side member rear reinforcement 36 is a hat shape. When the front side member rear reinforcement 36 is fitted in the cross section of the front side member rear 34, the flange portion 36 </ b> C and the side wall are sandwiched between the ridges 44 of the front side member rear reinforcement 36. Since the inner coupling point 46 and the outer coupling point 48 with the front side member rear 34 are set in the portion 36B, the ridgeline 44 can be effectively reinforced. The bending strength of the front side member rear 34 at the time of a frontal collision also changes depending on whether or not the ridgeline 44 is buckled. For example, the connecting point of the front side member rear 34 is set at the flange portion 36C and the bottom wall portion 36A. In comparison, the collision performance is improved. As a result, according to the present embodiment, it is possible to effectively improve the collision performance at the time of frontal collision.

  Further, since the bottom wall portion 36A of the front side member rear reinforcement 36 is separated from the bottom wall portion 34A of the front side member rear 34 and is not coupled, the front side member rear reinforcement 36 can be easily aligned with the front side member rear 34. . That is, if a structure is adopted in which the bottom wall portion 36A of the front side member rear reinforcement 36 is brought into contact with the bottom wall portion 34A of the front side member rear 34, the bottom wall portion can be set even if the coupling point is set between the flange portion 36C and the side wall portion 36B. Since 36A and 34A interfere with each other, the positioning becomes difficult, but if the bottom wall portion 36A of the front side member rear reinforcement 36 is separated from the bottom wall portion 34A of the front side member rear 34 as in the present embodiment, Productivity is kept good. Further, the weight of the vehicle body can be reduced by making the bottom of the front side member rear reinforcement 36 shallower.

  In addition, the flange portion 36C of the front side member rear reinforcement 36 is formed with notches 40 at a plurality of locations along the longitudinal direction, and the flange portion of the floor upper member 42 is formed at the position where the notch 40 is formed. 42C, the front floor panel 32, and the flange portion 34C of the front side member rear 34 are joined together, and the flange portion 36C of the front side member rear reinforcement 36 and the flange portion 34C of the front side member rear 34 are located at a position where the notch portion 40 is not formed. Therefore, the quality when joined by spot welding can be ensured. That is, as the overlapping of the plates, there are a total of four pieces of the flange portion 42C of the floor upper member 42, the front floor panel 32, the flange portion 36C of the front side member rear reinforcement 36, and the flange portion 34C of the front side member rear 34 from the top. For this reason, spot welding becomes difficult, but by forming the notch 40, it becomes three-layer spot welding or two-layer spot welding, so that the reliability (quality) for spot welding is maintained well and as a whole Four members can be connected. As a result, according to the present embodiment, the four members can be combined as a whole by spot welding, so that the productivity can be improved and the quality can be easily ensured. Can increase the sex.

  In the above-described embodiment, the rear end portion 36D of the front side member rear reinforcement 36 is extended to a position where it overlaps the first cross member 26 in a plan view. You may make it extend in the vehicle back side further predetermined length beyond an installation position.

FIG. 5 is an enlarged perspective view of a portion indicated by an arrow A in FIG. FIG. 2 is a main part enlarged perspective view showing a main part of the vehicle body lower structure shown in FIG. 1 as viewed from the vehicle rear side. It is a longitudinal cross-sectional view which follows the 3-3 line of FIG. It is a top view which shows the whole structure of a vehicle body lower frame.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Vehicle body lower frame 12 Front floor part 16 Floor side member 18 Front side member 26 1st cross member 32 Front floor panel (vehicle body floor)
34 Front side member rear 34A Bottom wall part 34C Flange part 36 Front side member rear reinforcement (reinforcing member)
36A Bottom wall portion 36B Side wall portion 36C Flange portion 36D Rear end portion 40 Notch portion 42 Floor upper member (reinforcing member)
42C flange portion 42D rear end portion 44 ridge line 46 inner coupling point 48 outer coupling point

Claims (4)

A front side member formed in a cross-sectional hat shape and joined to the lower surface of the vehicle body floor and extending along the vehicle longitudinal direction;
A cross member formed in a cross-sectional hat shape and joined to the upper surface of the vehicle body floor and extending along the vehicle width direction so as to intersect the front side member in plan view;
A reinforcing member that is arranged in a cross section of the front side member and extends along the vehicle longitudinal direction;
A reinforcing member formed in a cross-sectional hat shape, joined to a position overlapping the front side member in plan view on the upper surface of the vehicle body floor, and extending in the vehicle longitudinal direction;
A vehicle body lower structure having
The reinforcing member is terminated at the front position of the cross member, and the rear end portion of the reinforcing member is extended to the rear side of the vehicle until it overlaps the cross member in a plan view.
The underbody structure characterized by that. The reinforcing member has a hat-shaped cross section and is fitted inside the cross section of the front side member, and a coupling point of the front side member is set on the flange portion and the side wall portion so as to sandwich the ridgeline.
The vehicle body lower part structure according to claim 1. The bottom wall portion of the reinforcing member is separated from the bottom wall portion of the front side member and is not coupled;
The vehicle body lower part structure according to claim 2. The flange portion of the reinforcing member is formed with notches at a plurality of locations along the longitudinal direction, and at the position where the notch is formed, the flange portion of the reinforcing member, the vehicle body floor, and the flange portion of the front side member Are connected, and the flange part of the reinforcing member and the flange part of the front side member are connected at the position where the notch is not formed.
The vehicle body lower part structure according to any one of claims 1 to 3, wherein the vehicle body lower part structure is provided.

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