JP5577215B2 - Lower back structure of automobile - Google Patents

Description

  In the present invention, the lower side corner portion of the rear vehicle body in which the back door opening is formed is formed by joining the lower back outer panel extending in the vehicle width direction and the lower back extension outer panel extending in the vehicle vertical direction by spot welding. It relates to the lower back structure of an automobile.

  The lower corner of the rear part of a car body is generally constructed by overlapping the side edges of the lower back outer panel and the lower back extension outer panel and joining the upper flanges and lower flanges of the side edges by spot welding. is there.

  By the way, since the thrust load transmitted from the road surface through the rear wheel is repeatedly applied to the lower corner portion, the spot welding of the lower flange may be peeled off due to the thrust load. From the viewpoint of increasing the strength of the lower corner portion with respect to such push-up load, for example, in Patent Document 1, the side edge portions of the outer panel are joined together by two rows of spot welding. Further, in Patent Document 2, the side edge portions of the outer panel are joined by spot welding with a reinforcing member interposed therebetween.

JP 2007-55418 A JP 2000-72043 A

  By the way, in the said conventional structure, in order to prevent peeling of the spot welding by a thrust load, the number of spot hitting points is increased or a reinforcing member is added. For this reason, there is a problem that the cost and weight increase, and it is a structure that is difficult to be adopted for a small vehicle in which weight reduction and cost reduction are strongly desired. In view of this, there has been a demand for examination of an optimal structure in the lower corner portion of the back door opening in a small vehicle for which weight reduction and cost reduction are desired.

  SUMMARY OF THE INVENTION The present invention has been made in view of the above-described conventional situation, and it is possible to prevent spot welding peeling at the lower corner portion of the back door opening with respect to a thrust load from the road surface while reducing the weight and cost. It is an issue to provide.

  In the present invention, the lower side corner portion of the rear vehicle body in which the back door opening is formed is overlapped with the end edge portion of the lower back outer panel and the end edge portion of the lower back extension outer panel, and the upper flanges and lower A lower back structure for an automobile formed by connecting flanges by spot welding, wherein the lower flange outer panel or the lower back is connected to a general flange surface other than the lower flange connecting portion. The extension flange panel is bent so as to form an inclined surface that protrudes forward or backward from the vicinity of the edge of one of the panels, and the general flange starts from the vicinity of the tip of the inclined surface of the other panel. It is characterized by a convex shape formed by bending back to the surface.

  According to the lower back structure according to the present invention, the joint portion between the lower flange portions is bent so as to form an inclined surface projecting from the vicinity of the edge of one panel with respect to the general flange surface of the lower flange, and Since the convex portion was formed by bending the vicinity of the inclined surface of the other panel so that it returns to the general flange surface, the joint between the lower flanges is elastically deformed starting from the bent portion by the push-up load from the road surface. Further, it is possible to relieve the push-up load concentrated on the joint portion, and to prevent the opening of the joint portion due to welding peeling.

  In the present invention, since it is only necessary to form a convex portion on the lower flange so as to protrude from the general flange surface, the weight and cost of the vehicle body can be increased as compared to the case where the conventional spot welding hit points are increased or a reinforcing member is added. It can be used for small vehicles that require weight reduction and low cost.

1 is a rear view of a rear vehicle body according to a first embodiment of the present invention. It is a rear view of the lower back panel of the said rear vehicle body. FIG. 3 is a sectional view of the lower back panel (a sectional view taken along line III-III in FIG. 2). FIG. 4 is a sectional view of the lower back panel (a sectional view taken along line IV-IV in FIG. 2). It is sectional drawing (VV sectional view taken on the line of FIG. 2) of the said lower back panel. It is sectional drawing (VI-VI sectional view taken on the line of FIG. 2) of the said lower back panel. It is sectional drawing (VII-VII sectional view taken on the line of FIG. 2) of the said lower back panel. It is a perspective view of the lower side corner part of the said lower back panel. It is a schematic diagram which shows the deformation | transformation state of the said lower side corner part.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

  FIGS. 1 to 8 are views for explaining a lower back structure of an automobile according to a first embodiment of the present invention. In the description of the present embodiment, front and rear and left and right mean front and rear and left and right when viewed in the vehicle traveling direction while seated on a seat mounted on the vehicle, unless otherwise specified.

  In the figure, reference numeral 1 denotes a rear body of the automobile. The rear vehicle body 1 includes left and right rear pillars 2 and 2 extending in the vertical direction of the vehicle, a rear header panel 3 disposed between upper ends of the left and right rear pillars 2, and a lower disposed between lower ends. A back door opening 1 a is formed with the back panel 4.

  A back door 5 that opens and closes the back door opening 1a is supported on the rear header panel 3 via a hinge (not shown) so as to be rotatable. A seal member 6 that seals between the back door 5 and the back door 5 is mounted on the periphery of the back door opening 1a.

  The lower back panel 4 forms the left and right lower corners 1b and 1b of the rear vehicle body 1, and forms a closed cross section between the lower back inner member 8 and the lower back outer member 9 extending in the vehicle width direction. It has a general structure connected in this way. Here, since the left and right lower side corner portions 1b have substantially the same structure, the right side lower side corner portion 1b will be mainly described.

  The lower back inner member 8 includes a lower back inner panel 10 that forms a central portion in the vehicle width direction, and a lower back extension inner panel 11 that forms left and right side portions.

  The lower back inner panel 10 has a strip shape extending in the vehicle width direction. The lower back extension inner panel 11 is substantially L-shaped and extends upward following the lower back inner panel 10.

  The lower back outer member 9 includes a lower back outer panel 12 that forms a central portion in the vehicle width direction, and lower back extension outer panels 13 and 13 that form left and right sides.

  The lower back outer panel 12 has a strip shape extending in the vehicle width direction, and is longer in the vehicle width direction than the lower back inner panel 10. The lower back extension outer panel 13 extends upward following the lower back outer panel 12, and a lower corner portion 1b is formed between a lower portion of the extension outer panel 13 extending in the vertical direction and a side portion of the lower back outer panel 12. Is formed.

  The lower back extension outer panel 13 is formed with a housing recess 13e for housing the rear combination lamp 14, and a ventilation hole 13f for discharging room air to the outside is formed under the housing recess 13e.

  The lower back inner panel 10 and the lower back outer panel 12 have a hat shape in cross section, and are joined by spot welding the upper flanges 10a, 12a and the lower flanges 10b, 12b (FIG. 6). reference). A lower edge of the back door opening 1a is formed by the upper flanges 10a and 12a.

  The lower back inner panel 10 is formed with a license plate mounting portion 10c extending downward from the lower flange 10b. A rear bumper 15 is attached to the lower back outer panel 12 by a clip 16.

  An upper flange 12a of the lower back outer panel 12 and an upper flange 13a of the lower back extension outer panel 13 are joined to the upper flange 11a of the lower back extension inner panel 11 by spot welding. The lower flange portion of the back door opening 1a is formed by the upper flanges 11a, 12a, and 13a.

  The lower flange 11b of the lower back extension inner panel 11 is joined to the lower flange 12b of the lower back outer panel 12 and the lower flange 13b of the lower back extension outer panel 13 by spot welding. The lower flange portion 11b, 12b, 13b forms the lower edge portion of the lower side corner portion 1b.

  An inner edge portion 11d of the lower back extension inner panel 11 is overlapped and joined to the outer edge portion 10d of the lower back inner panel 10 by spot welding (see the crosses in FIG. 2). Three upper flanges 12a of the lower back outer panel 12 are overlapped and joined by spot welding to the upper flanges 10a, 11a of the side edge portions 10d, 11d of the inner panels 10, 11.

  A rear end flange 18a of the rear side member 18 extending in the vehicle front-rear direction is joined to the front wall surface of the lower back extension inner panel 11 by welding.

  An end edge portion 13d on the inner side in the vehicle width direction of the lower back extension outer panel 13 is overlapped with and joined to the end edge portion 12d on the outer side in the vehicle width direction of the lower back outer panel 12 by spot welding w1.

  Three upper flanges 11a of the lower back extension inner panel 11 are joined to each other by spot welding w2 on the upper flanges 12a, 13a of both end edges 12d, 13d of the outer panels 12, 13 respectively.

  Three lower flanges 11b of the lower back extension inner panel 11 are joined to each other by spot welding w3 on the lower flanges 12b, 13b of both end edges 12d, 13d of the outer panels 12, 13 respectively.

  Between the lower flange 13b of the lower back extension outer panel 13 and the lower flange 11b of the lower back extension inner panel 11, an upper end portion of a bracket 20 for attaching the rear bumper 15 is inserted and arranged. They are joined together by spot welding w4. The bracket 20 is disposed in the vicinity of the outer side in the vehicle width direction of the lower flanges 12b and 13b of the end edge portions 12d and 13d.

  The joint A between the lower flanges 12b and 13b of the both end edges 12d and 13d forms a convex portion 21 projecting rearward from the general flange surface a other than the joint A of the lower flange 12b. (See FIG. 5).

  In detail, the said convex part 21 is comprised as follows. The end edge 13d of the lower back extension outer panel 13 is bent so as to form an inclined surface b projecting rearward by b 'with respect to the general flange surface a starting from the edge vicinity 13d'. Subsequently, the lower back outer panel 12 is formed so as to form a flat surface c extending substantially parallel to the general flange surface a starting from the tip vicinity portion 12d 'of the inclined surface b thereof, and therefore on the general flange surface a side. Bend it back slightly. Subsequently, the flat surface c is further bent so as to form an inclined surface c that returns to the general flange surface a from the front end portion 12d ″ of the flat surface c.

  Here, “bending to return to the general flange surface starting from the vicinity of the tip of the inclined surface” in the present invention is a flat surface c substantially parallel to the general flange surface a starting from the vicinity 12d ′ of the tip in the present embodiment. It includes a configuration that bends to form

  In this way, the coupling portion A forms a convex portion 21 having a trapezoidal cross section by the inclined surface b, the flat surface c, and the inclined surface d. Further, the starting point 12d ′ and the starting point 12d ″ form a polygonal line e.

  A bent portion 22 having a shape along the convex portion 21 is formed at a portion corresponding to the convex portion 21 of the lower flange 11 b of the lower back extension inner panel 11. The portions of the bent portion 22 that are in contact with the flat surface c and the inclined surface d of the lower back outer panel 12 are joined by spot welding w5.

  The bent portion 22 of the extension inner panel 11 is formed so as to extend upward following the lower flange 11b. As described above, since the bent portion 22 of the extension inner panel 11 is formed to extend from the lower flange 11b, the formability when forming the bent portion 22 on the extension inner panel 11 having a large plate thickness can be improved and pushed up. Deformation with respect to load becomes easy.

  According to the present embodiment, the inclined surface b, the flat surface c, and the flat surface c are formed by projecting the joint portion A of the lower flanges 12b and 13b joined by spot welding w3 backward by b with respect to the general flange surface a of the lower flange 12b. Since the trapezoidal convex part 21 having the polygonal lines e and e is formed by the inclined surface d, the convex part 21 part is deformed from the polygonal lines e and e by the push-up load from the road surface. The push-up load concentrated on the part A can be relaxed, and the opening of the joint A due to the peeling of the weld can be prevented.

  That is, the back door opening 1a expands and contracts in the diagonal direction due to the thrust load from the road surface transmitted through the rear wheel (see the two-dot chain line in FIG. 1). There is a concern that the stress due to the repeated pushing load concentrates on the lower side corner portion 1c, the welding of the lower flange 13b portion of the end edge portion 13d of the extension outer panel 13 is peeled off, and the lower flange 13b portion opens.

  In contrast, in the present embodiment, since the convex portions 21 having the folding lines e and e are formed on the lower flanges 12b and 13b, the convex portions 21 are elastically deformed in the vehicle width direction and pushed up as shown in FIG. By absorbing the load, the stress concentration on the coupling portion A is alleviated, and the aforementioned opening can be prevented.

  In the present embodiment, it is only necessary to form the convex portion 21 projecting from the general flange surface a on the lower flanges 12b and 13b, so that compared with the case where the number of spot welding hit points is increased or a reinforcing member is added. Thus, the weight and cost of the vehicle body can be reduced, and it can be applied to a small vehicle where weight reduction and low cost are desired.

  That is, in order to prevent the above-mentioned opening of the mouth, it is considered that the end edge portion 13d of the lower back extension outer panel 13 is extended, thereby increasing the amount of lap with the outer panel 12 and increasing the number of spot hitting points of three sheets. It is done. However, in this case, the cost and weight of the extension outer panel increase. In the present embodiment, the lap amount of the extension outer panel can be minimized, and the number of spot hits of three sheets can be suppressed to one place w3. From this point, the cost and weight can be reduced. .

  In the embodiment, the inclined surface b is formed on the lower back extension outer panel 13 side, and the flat surface c and the inclined surface d are formed on the lower back outer panel 12 side. It may be formed on the lower back outer panel 12 side, and the flat surface c and the inclined surface d may be formed on the lower back extension outer panel 13 side. In this case, the shape is symmetrical to FIG.

  Moreover, in the said Example, although the said convex part 21 was formed in trapezoid shape, the convex part of this invention is not limited to trapezoid shape. For example, the inclined surface b and the inclined surface d may be triangular convex portions without providing the flat surface c.

  Furthermore, in the said Example, although the convex part was formed so that it might protrude on the back of a vehicle, you may form this so that it may protrude ahead.

DESCRIPTION OF SYMBOLS 1 Rear vehicle body 1a Back door opening 1b Lower side corner part 12 Lower back outer panel 12a Upper flange 12b Lower flange 12d End edge part 12d 'Front end part 13 Lower back extension outer panel 13a Upper flange 13b Lower flange 13d End edge part 13d' Near edge Part 21 Convex part A Joint part a General flange surface c Polygonal line

Claims (1)

At the lower corner of the rear body where the back door opening is formed, the end edge of the lower back outer panel and the end edge of the lower back extension outer panel are overlapped, and the upper flanges and lower flanges of the both end edges are spotted. A lower back structure of an automobile formed by welding,
The connecting portion between the lower flanges is the front of the vehicle starting from the vicinity of the edge of one of the lower back outer panel and the lower back extension outer panel with respect to the general flange surface other than the connecting portion of the lower flange. An automobile having a convex shape formed by bending so as to form an inclined surface projecting rearward and bending the other panel so as to return to the general flange surface starting from the vicinity of the tip of the inclined surface. Lower back structure.

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