JP5699966B2 - Body structure - Google Patents

Description

  The present invention relates to a vehicle body structure provided with a resin floor.

  An underbody structure composed of a resin floor panel and a vehicle body skeleton member disposed on the outer periphery of the resin floor panel is conventionally known (see, for example, Patent Document 1). Further, a vehicle body floor structure in which a rocker, a floor panel, a dash panel, a cross member, a front cross member, and a rear cross member are made of carbon fiber reinforced plastic has been conventionally known (see, for example, Patent Document 2). .

JP-A 64-22681 JP 2008-155700 A

  In such an underbody structure or a vehicle body floor structure, it is desired to efficiently transmit a load input from the front and rear direction of the vehicle body at the time of a frontal collision or a rear surface collision, and the transmission efficiency is still not improved. There is room for improvement.

  SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to obtain a vehicle body structure that can efficiently transmit a load input from the longitudinal direction of the vehicle body.

  In order to achieve the above object, a vehicle body structure according to claim 1 of the present invention includes a resin lower panel having a lower wall constituting a lower portion of a floor portion, a vehicle width direction center portion of the floor portion, and A tunnel portion and a rocker portion having a closed cross-sectional structure extending in the longitudinal direction of the vehicle body are formed on both side portions so as to face the lower wall, and a groove portion between the tunnel portion and the rocker portion is formed on the front side of the vehicle body. And an opening having a tapered shape on the rear side of the vehicle body, and a joint portion to be joined to the joined portion of the lower wall in the groove portion on the vehicle body front side and the vehicle body rear side of the opening. And a resin upper panel having a wall.

  According to the first aspect of the present invention, the groove portion between the tunnel portion and the rocker portion on the upper wall is formed with the opening portion having a tapered shape on the vehicle body front side and the vehicle body rear side, and the vehicle body of the opening portion. Joined portions that are joined to the joined portions of the lower wall are formed in the groove portions on the front side and the vehicle body rear side, respectively. Therefore, a part of the load input from the front-rear direction of the vehicle body, such as at the time of a frontal collision or a rearward collision, is transmitted to the joint (joined part).

  Here, an opening having a tapered shape on the front side of the vehicle body is formed on the rear side of the joint portion on the front side of the vehicle body, and an opening having a tapered shape on the rear side of the vehicle body is provided on the front side of the joint portion on the rear side of the vehicle body. The part is formed. Therefore, the load transmitted to the joint portion (joined portion) on the front side of the vehicle body or the joint portion (joined portion) on the rear side of the vehicle body is guided and distributed to both sides in the vehicle width direction of the groove portion by the tapered shape. . That is, the load is transmitted to and absorbed by the side wall of the tunnel portion and the side wall of the rocker portion that face each other in the vehicle width direction. As described above, according to the present invention, it is possible to efficiently transmit the load input from the longitudinal direction of the vehicle body to the tunnel portion and the rocker portion.

  Further, the vehicle body structure according to claim 2 is the vehicle body structure according to claim 1, wherein an attachment hole for attaching a front suspension member is formed in the joint portion and the joint portion on the front side of the vehicle body. An attachment hole for attaching a rear suspension member is formed in the joining portion and the joined portion on the rear side of the vehicle body.

  According to the second aspect of the present invention, it is possible to efficiently transmit the load input to the front suspension member to the joint portion (joined portion) on the front side of the vehicle body, and the load input to the rear suspension member. Can be efficiently transmitted to the joint portion (joined portion) on the vehicle body rear side.

  Further, the vehicle body structure according to claim 3 is the vehicle body structure according to claim 1 or 2, wherein the upper wall extends in the vehicle width direction in the vehicle body longitudinal direction middle portion of the floor portion. The cross section of the closed cross-sectional structure is configured to face the lower wall.

  According to the third aspect of the present invention, the cross portion having a closed cross-sectional shape extending in the vehicle width direction is formed on the floor portion. Therefore, it is possible to efficiently transmit the load input from the vehicle width direction to the cross portion during a side collision or the like.

  As described above, according to the present invention, it is possible to efficiently transmit a load input from the front-rear direction of the vehicle body.

It is a sectional side view which shows schematic structure of the motor vehicle provided with the resin body structure. It is a disassembled perspective view which shows the upper panel and lower panel which comprise the floor part of a resin body structure seeing from a vehicle body back. It is a disassembled perspective view which shows the upper panel and lower panel which comprise the floor part of a resin body structure seeing from a vehicle body front. It is a perspective view which shows the floor part of the resin body structure where the front suspension member was attached seeing from the vehicle body rear. It is a perspective view which shows the floor part of the resin body structure where the rear suspension member was attached seeing from the vehicle body front. It is a top view which shows the structure of the floor part of a resin body structure. It is a perspective view which expands and shows the structure of a junction part.

  Hereinafter, embodiments according to the present invention will be described in detail with reference to the drawings. Note that an arrow FR appropriately shown in the drawing indicates a forward direction in the vehicle longitudinal direction, an arrow UP indicates an upward direction in the vehicle vertical direction, and an arrow OUT indicates an outside in the vehicle width direction. Further, in the following description, when using front / rear, up / down, and left / right directions unless otherwise specified, front / rear in the front / rear direction of the vehicle, up / down in the up / down direction of the vehicle, and left / right in the left / right direction of the vehicle (vehicle width direction).

  As shown in FIG. 1, a resin body structure 10 as a vehicle body structure according to the present embodiment is applied to an (electric) automobile V as a vehicle. The resin body structure 10 includes an underbody 12, a front suspension module 14, a front energy absorbing member (hereinafter referred to as “front EA member”) 16, a rear suspension module 18, and a rear energy absorbing member (hereinafter referred to as “rear EA member”). ”) 20).

(Underbody structure)
As shown in FIGS. 2 and 3, the resin underbody 12 is composed of a lower panel 12L and an upper panel 12U, and the lower panel 12L and the upper panel 12U are joined to each other so as to have a substantially rectangular shape in plan view. The floor portion 22 is configured (see FIG. 6).

  The underbody 12 includes a dash lower portion 24 as a front wall portion standing upward from the front end of the floor portion 22, and a lower back as a rear wall portion standing upward from the rear end of the floor portion 22. Part 26. The dash lower portion 24 and the lower back portion 26 have a length extending over substantially the entire width of the floor portion 22, and are formed in a substantially rectangular shape whose longitudinal direction is the vehicle width direction when viewed from the front.

  Further, as shown in FIGS. 4 and 5, front side walls 28 extend rearward from both ends of the dash lower portion 24 in the vehicle width direction, and forward and rearward from both ends of the lower back portion 26 in the vehicle width direction. A side wall 30 is extended. Each of the front side wall 28 and the rear side wall 30 has a lower end continuous to the outer end portion in the vehicle width direction of the floor portion 22 (a rocker portion 36 to be described later), and is separated from each other in the front-rear direction. As described above, the underbody 12 is formed in a bathtub shape as a whole (a bathtub shape in which a part of the side wall is cut out).

  As shown in FIGS. 1 to 5, the floor portion 22 includes a lower wall 32 that is flat along a substantially horizontal plane, and an upper wall 40 that is opposed to the lower wall 32 in the vertical direction and is flat along a substantially horizontal plane. , 44. The floor portion 22 is formed with a pair of left and right rocker portions 36 as side skeleton structure portions whose longitudinal directions are the longitudinal directions, and a tunnel portion 38 as a center skeleton structure portion.

  The pair of left and right rocker portions 36 includes a lower wall 32, an upper wall 40 as a rocker wall facing the lower wall 32 up and down, an outer wall 34 erected upward from both sides in the vehicle width direction of the lower wall 32, The outer side wall 34 and the inner side wall 42 as a vertical wall facing in the vehicle width direction (facing in the vehicle width direction) are configured in a rectangular frame-like closed cross-sectional structure in a front sectional view.

  The tunnel portion 38 includes a lower wall 32, an upper wall 44 as a tunnel wall facing the lower wall 32 vertically, and a center side wall 46 as a pair of vertical walls facing each other (facing in the vehicle width direction). It has a rectangular frame-like closed cross-sectional structure in cross-sectional view.

  In the present embodiment, the upper wall 40 on both sides in the vehicle width direction and the upper wall 44 in the center in the vehicle width direction are configured such that the facing distance from the lower wall 32 is different. That is, the left and right rocker portions 36 are configured to be higher than the tunnel portion 38. Further, by forming the left and right rocker portions 36 and the tunnel portion 38 on the floor portion 22, a bottom groove portion 41 is formed between the upper wall 40 and the upper wall 44 as a groove portion that is concave in a front sectional view. Has been.

  As shown in detail in FIG. 6, the bottom groove portion 41 on the front side of the center cross portion 60 to be described later has a rectangular shape in which the vehicle body rear side end substantially reaches the front wall 64 (described later), and the vehicle body front side An opening (long hole) 41A having a tapered end is formed. The bottom groove 41 on the rear side of the center cross portion 60 has a rectangular shape in which the front end portion of the vehicle body substantially reaches the rear wall 66 (described later), and the end portion on the rear side of the vehicle body is tapered. An opening (long hole) 41B is formed.

  Further, a bottom groove 41 on the front side of the vehicle body relative to the opening 41A (a vehicle front side portion excluding the opening 41A in the bottom groove 41 on the front side) is a joint 80 that is joined to the lower wall 32. Two attachment holes 80A for attaching a later-described front suspension member 70 are formed side by side in the vehicle longitudinal direction at the vehicle width direction central portion of the portion 80.

  A part of the bottom groove 41 around the opening 41 </ b> A excluding the joint 80 is an upper flange 12 </ b> UF that is joined to the lower wall 32. Further, in the lower wall 32, a portion where the joining portion 80 is overlapped (a region indicated by an imaginary line in FIG. 2) is a joined portion 81, and an attachment hole 81A equivalent to the attachment hole 80A is formed.

  On the other hand, the bottom groove 41 on the vehicle rear side of the opening 41B (the vehicle rear side portion excluding the opening 41B in the bottom groove 41 on the rear side) is a joint 82 that is joined to the lower wall 32. Two attachment holes 82A for attaching a rear suspension member 72, which will be described later, are formed in the vehicle width direction center portion of the joint portion 82, side by side in the longitudinal direction of the vehicle body.

  A part of the bottom groove 41 around the opening 41 </ b> B excluding the joint 82 is an upper flange 12 </ b> UF that is joined to the lower wall 32. Further, in the lower wall 32, a portion where the joining portion 82 is overlapped (a region indicated by an imaginary line in FIG. 3) is a joined portion 83, and an attachment hole 83A equivalent to the attachment hole 82A is formed.

  As shown in FIGS. 4 and 5, the dash lower portion 24 is configured by three closed cross-sectional structures that are integrally continuous upward from the front end portions of the left and right rocker portions 36 and the tunnel portion 38. Yes. Similarly, the lower back portion 26 is configured by three closed cross-sectional structures that are integrally continuous from the rear end portions of the left and right rocker portions 36 and the tunnel portion 38 upward.

  Specifically, as shown in FIGS. 2 and 4, the dash lower portion 24 includes an outer front wall 48 and an inner front wall 50 that oppose each other, a lower wall 32, and an upper wall 52 that opposes the lower wall 32. , And is configured.

  The inner front wall 50 includes an inner side wall 43 as a vertical wall integrally formed by extending the inner side walls 42 constituting the left and right rocker portions 36 toward the front side of the vehicle body, and a center side wall 46 constituting the tunnel portion 38. A center side wall 47 as a vertical wall integrally formed by extending to the front side of the vehicle body, and a front groove portion 51 integrally formed by extending the bottom groove portion 41 to the front side of the vehicle body.

  A rectangular (square) opening 51A is formed in the front groove 51, and rectangular (trapezoidal) openings 51B are also formed on both sides of the inner front wall 50 in the vehicle width direction. . Then, by joining the two front groove portions 51 of the inner front wall 50 to the outer front wall 48, three closed cross-sectional shapes are formed side by side in the vehicle width direction in the dash lower portion 24. Yes.

  That is, the dash lower portion 24 has a closed cross-sectional structure (closed) with the lower wall 32, the outer front wall 48, the inner front wall 50, the upper wall 52, each inner side wall 43, and each center side wall 47. Three cross-sectional shapes) are configured (formed) in the vehicle width direction.

  The lower part continuous with the upper walls 40, 44 of the inner front wall 50 is an inclined wall 50S (see FIG. 1). The inclined wall 50S is inclined with respect to the front / rear (horizontal) direction so that the rear end side is positioned below the front end side, and the front upper end thereof is an upper / lower wall 50V (almost along the vertical direction of the inner front wall 50). (See FIG. 1). The rear lower end of the inclined wall 50 </ b> S is continued to the front end of the upper wall 40 or the upper wall 44.

  On the other hand, as shown in FIGS. 3 and 5, the lower back portion 26 has an outer rear wall 54 and an inner rear wall 56 that face each other in the front-rear direction, a lower wall 32, and an upper wall 58 that faces the lower wall 32. Configured.

  The inner rear wall 56 includes an inner side wall 45 as a vertical wall integrally formed by extending the inner side walls 42 constituting the left and right rocker portions 36 toward the rear side of the vehicle body, and a center side wall 46 constituting the tunnel portion 38. A center side wall 49 as a vertical wall integrally formed extending to the rear side of the vehicle body, and a rear groove portion 57 integrally formed by extending the bottom groove portion 41 to the rear side of the vehicle body.

  In the rear groove portion 57, a rectangular (square) opening 57A is formed. Then, the two rear groove portions 57 of the inner rear wall 56 are joined to the outer rear wall 54, so that three closed cross-sectional shapes are formed side by side in the vehicle width direction in the lower back portion 26. .

  In other words, the lower back portion 26 includes a lower wall 32, an outer rear wall 54, an inner rear wall 56, an upper wall 58, each inner side wall 45, and each center side wall 49. (Shape) is configured (formed) in the vehicle width direction.

  In addition, the lower part continuing to the upper walls 40 and 44 of the inner rear wall 56 is an inclined wall 56S (see FIG. 1). The inclined wall 56S is inclined with respect to the front / rear (horizontal) direction so that the front end side is located below the rear end side, and the upper end of the inclined wall 56S is an upper / lower wall 56V ( (See FIG. 1). The front lower end of the inclined wall 56S is continued to the rear end of the upper wall 40 or the upper wall 44.

  Further, the floor portion 22 has a center cross portion 60 that bridges the left and right rocker portions 36 and the tunnel portion 38 at a substantially central portion in the vehicle longitudinal direction (extends in the vehicle width direction). The center cross portion 60 includes a lower wall 32, an upper wall 62 as a cross wall facing the lower wall 32 in the vertical direction, and a front wall 64 and a rear wall 66 facing the front and rear. It has a cross-sectional structure (see FIG. 1).

  The underbody 12 described above is made of a resin material. Examples of the resin material constituting the underbody 12 include fiber reinforced resins containing reinforcing fibers such as carbon fibers, glass fibers, and aramid fibers.

  And this underbody 12 (floor part 22) overlaps the lower panel 12L and the upper panel 12U up and down, as shown in FIGS. 2-5, and is comprised by the adhesive agent.

  Specifically, the lower panel 12L includes a lower wall 32 (joined portions 81 and 83), an outer wall 34, an outer front wall 48 of the dash lower portion 24, an outer rear wall 54 of the lower back portion 26, and a front side wall 28. The outer wall 28 </ b> A, the rear wall 30 </ b> A of the rear side wall 30, and the lower flange 12 </ b> LF projecting outward from the peripheral edge in a plan view.

  The upper panel 12U includes an upper wall 40 and an inner side wall 42 of the rocker portion 36, an upper wall 44 and a center side wall 46 of the tunnel portion 38, an inner front wall 50, an upper wall 52, an inner side wall 43 and a center side wall of the dash lower portion 24. 47, an inner rear wall 56, an upper wall 58, an inner wall 45 and a center side wall 49 of the lower back portion 26, an upper wall 62, a front wall 64 and a rear wall 66 of the center cross portion 60, and an inner wall 28B of the front side wall 28. The rear wall 30 includes an inner wall 30B and an upper flange 12UF that protrudes outward from the peripheral edge in plan view.

  Further, the upper panel 12U includes a bottom groove portion 41 (joint portions 80 and 82) formed between the tunnel portion 38 and the rocker portion 36, a front groove portion 51 formed on the inner front wall 50, and an inner rear wall. 56 and a rear groove portion 57 formed on the inner surface 56. As described above, the upper flange 12UF is also formed in a part of the bottom groove 41 around the openings 41A and 41B excluding the joints 80 and 82.

  Therefore, the lower body 12L includes the lower panel 12L and the upper panel 12U, the lower flange 12LF and the upper flange 12UF, the lower wall 32 and the upper flange 12UF, the lower wall 32 (joined portions 81 and 83) and the joined portions 80 and 82, The front wall 48 and the front groove portion 51, and the outer rear wall 54 and the rear groove portion 57 are bonded to each other to form the above-described closed cross-sectional structures. The front side wall 28 forms a closed cross-sectional structure with the outer wall 28A and the inner wall 28B, and the rear side wall 30 forms a closed cross-sectional structure with the outer wall 30A and the inner wall 30B.

(Configuration of suspension module)
As shown in FIG. 1, the front suspension module 14 includes at least a front suspension member 70 and a pair of left and right front suspensions (not shown). The front suspension member 70 has a closed cross-sectional structure in a side cross-sectional view of FIG.

  Further, the left and right front suspensions are assembled to the front suspension member 70 as a whole, and the front suspension member 70 supports the front wheels Wf via each front suspension so as to be steerable. That is, each front suspension is supported by the front suspension member 70 so as to function independently without depending on other parts constituting the vehicle body of the automobile V.

  On the other hand, the rear suspension module 18 includes at least a rear suspension member 72 and a pair of left and right rear suspensions (not shown). The left and right rear suspensions are assembled as a whole to the rear suspension member 72, and the rear suspension member 72 is configured to rotatably support the rear wheel Wr via each rear suspension. That is, each rear suspension is supported by the rear suspension member 72 so as to function independently without depending on other parts constituting the vehicle body of the automobile V.

  Furthermore, a wheel-in motor (not shown) is built in the rear wheel Wr. The rear suspension module 18 is assembled with a battery (not shown) for driving the wheel-in motor and a PCU (power control unit) as a control device. Therefore, the rear suspension module 18 can also be regarded as a drive unit of the automobile V.

  The front suspension member 70 is fastened to the outer front wall 48 and the joining portion 80 (joined portion 81) of the dash lower portion 24 by fastening, and the rear suspension member 72 is the outer rear wall 54 of the lower back portion 26. And it is being fixed to the junction part 82 (to-be-joined part 83) by fastening.

  Specifically, a flange 74 that extends to the rear side of the vehicle body is formed integrally with the lower portion of the front suspension member 70, and the flange 74 is configured to be able to overlap the joined portion 81 from below. Has been. A bolt insertion hole 74 </ b> A (see FIG. 4) is formed in the vehicle width direction center portion of the flange 74 side by side in the vehicle body front-rear direction.

  Therefore, the flange 74 is overlapped on the joined portion 81 from the lower side of the vehicle body, the bolt insertion hole 74A and the mounting holes 81A, 80A are inserted from the lower side thereof, and the bolt 84 as a fastener is inserted into the nut 86 on the joined portion 80. By screwing, the flange 74 is fastened and fixed to the joining portion 80 (joined portion 81) (see FIG. 1).

  Further, a bolt (not shown) inserted from the rear wall 78 side (front side of the vehicle body) of the front suspension member 70 is inserted into a mounting hole 48A (see FIGS. 2, 3, and 5) formed in the outer front wall 48. Then, a nut (not shown) is screwed into the opening 51A, whereby the rear wall 78 is fastened and fixed to the outer front wall 48. As described above, the front suspension member 70 is fastened and fixed to the dash lower portion 24.

  On the other hand, a flange 76 that extends to the front side of the vehicle body is integrally formed at the lower portion of the rear suspension member 72, and the flange 76 is configured to be able to overlap the joined portion 83 from below. Yes. A bolt insertion hole 76 </ b> A (see FIG. 5) is formed in the vehicle width direction center portion of the flange 76 side by side in the vehicle body longitudinal direction.

  Therefore, the flange 76 is overlapped with the joined portion 83 from the lower side of the vehicle body, and the bolt 84 as a fastener is inserted into the bolt insertion hole 76A and the attachment holes 83A and 82A from the lower side, and the nut 86 is placed on the joined portion 82. The flange 76 is fastened and fixed to the joining portion 82 (joined portion 83) (see FIG. 1).

  As shown in FIG. 5, the rear suspension member 72 is formed with a mounting plate 68 facing the front side of the vehicle body, and the mounting plate 68 projects to the rear side of the vehicle body on the outer rear wall 54 of the lower back portion 26. In this way, the projection wall 54A (see FIGS. 2 to 4) integrally formed can be overlaid. The projecting wall 54A and the mounting plate 68 are respectively formed with mounting holes 54B (see FIGS. 2 to 4) and bolt insertion holes (not shown) arranged in the vertical direction of the vehicle body.

  Therefore, the mounting plate 68 is overlapped with the protruding wall 54A from the rear side of the vehicle body, the bolt (not shown) is inserted into the bolt insertion hole and the mounting hole 54B from the rear side, and the nut (not shown) is screwed into the opening 57A. As a result, the mounting plate 68 is fastened and fixed to the protruding wall 54A. As described above, the rear suspension member 72 is fastened and fixed to the lower back portion 26.

(Configuration of EA member)
As shown in FIG. 1, the front EA member 16 has a box shape (substantially approximately the same length as the front suspension member 70 in the vehicle width direction (interval between the left and right front suspensions) along the vehicle width direction. It is formed in a rectangular box shape. The front EA member 16 is fastened and fixed to the front suspension member 70 at a flange 16F protruding from its rear end.

  On the other hand, the rear EA member 20 has a box shape (substantially rectangular box shape) having a length along the vehicle width direction substantially equal to the length of the rear suspension member 72 in the vehicle width direction (interval between the left and right rear suspensions). Is formed. The rear EA member 20 is fastened and fixed to the rear suspension member 72 at flanges 20F protruding from both ends in the vehicle width direction.

  The front EA member 16 and the rear EA member 20 described above are integrally formed with resin parts. Examples of the resin material constituting the front EA member 16 and the rear EA member 20 include fiber reinforced resins containing reinforcing fibers such as carbon fibers, glass fibers, and aramid fibers. The front EA member 16 and the rear EA member 20 may be made of a metal material such as aluminum or an alloy thereof.

(Function)
Next, the operation of the resin body structure 10 configured as described above will be described.

  In the (electric) vehicle V to which the resin body structure 10 according to this embodiment is applied, electric power is supplied from the PCU built in the rear suspension member 72 to the wheel-in motor of the rear wheel Wr, and the driving force of the wheel-in motor is supplied. Travel by. In this automobile V, the front wheels Wf supported via the front suspension are steered in response to steering by a steering wheel (not shown).

  In the automobile V, when a frontal collision occurs, a collision load is input to the front EA member 16. The front EA member 16 is compressed and deformed by the collision load, and transmits a load (support reaction force) to the front suspension member 70 while absorbing impact energy (dynamic load).

  At this time, the collision load input to the front EA member 16 is received by the wide surface of the front suspension member 70 (a wall long in the vehicle width direction), and the front EA member 16 is stably compressed and deformed. Therefore, the collision load is efficiently absorbed by the front EA member 16.

  The collision load transmitted to the front suspension member 70 without being separated by the front EA member 16 is transmitted to the floor portion 22 via the dash lower portion 24 and absorbed by the floor portion 22.

  Specifically, the load input from the front EA member 16 to the dash lower portion 24 via the rear wall 78 of the front suspension member 70 is divided into three closed cross-sectional structures formed in the dash lower portion 24, that is, each closed cross-sectional structure. Are respectively received by the inner side walls 43 and the center side walls 47 of the inner front wall 50.

  Therefore, bending deformation of the outer front wall 48 toward the rear side of the vehicle body can be suppressed, and the ridgeline R1 (see FIG. 5) on each inner side wall 42 on the front side of the rocker portion 36 from each inner side wall 43 and each center side wall 47 of the inner front wall 50. 4) and the ridgeline R2 (see FIG. 4) in each center side wall 46 on the front side of the tunnel portion 38 can be transmitted.

  That is, the three closed cross-sectional structures (closed cross-sectional shapes) formed in the dash lower portion 24 are formed continuously with the rocker portion 36 and the tunnel portion 38 of the floor portion 22, respectively. Therefore, the load input to the dash lower portion 24 is efficiently transmitted from the dash lower portion 24 to the rocker portion 36 and the tunnel portion 38 of the floor portion 22 and absorbed.

  Further, the flange 74 of the front suspension member 70 is fastened and fixed to the joint 80 (joined part 81) by bolts 84 and nuts 86. Accordingly, the load transmitted to the front suspension member 70 is also transmitted to the joint 80 (joined part 81) via the flange 74 and the bolt 84 (fastener).

  Here, in the bottom groove portion 41 on the front side of the center cross portion 60, an opening portion 41A having a tapered front end portion on the vehicle body is formed. Therefore, as shown in FIGS. 6 and 7, the load transmitted from the front side of the vehicle body to the rear side of the vehicle body is guided to both sides of the bottom groove portion 41 in the vehicle width direction. To be distributed. That is, the load is transmitted to the inner side walls 43 and 42 and the center side walls 47 and 46 that face each other in the vehicle width direction.

  As a result, stress concentration around the mounting holes 80A and 81A of the joint 80 (joined part 81) is alleviated, and the load on the bolt 84 can be reduced. The load is efficiently applied to the rocker 36 and the tunnel 38. Well transmitted and absorbed. Therefore, deformation of the floor portion 22 can be suppressed.

  Further, in this automobile V, when a rear collision occurs, a collision load is input to the rear EA member 20. The rear EA member 20 is compressed and deformed by the collision load, and transmits a load (support reaction force) to the rear suspension member 72 while absorbing impact energy (dynamic load).

  At this time, the collision load input to the rear EA member 20 is received by the wide surface of the rear suspension member 72 (a wall long in the vehicle width direction), and the rear EA member 20 is stably compressed and deformed. Therefore, the collision load is efficiently absorbed by the rear EA member 20.

  The collision load transmitted to the rear suspension member 72 without being separated by the rear EA member 20 is transmitted to the floor portion 22 via the lower back portion 26 and absorbed by the floor portion 22.

  Specifically, the load input from the rear EA member 20 to the lower back portion 26 via the mounting plate 68 of the rear suspension member 72 is applied to the three closed cross-sectional structures formed on the lower back portion 26, that is, the respective closed cross-sectional structures. The inner rear wall 56 and the center side wall 49 of the inner rear wall 56 are configured to be received.

  Therefore, bending deformation of the outer rear wall 54 toward the front side of the vehicle body can be suppressed, and the ridgeline R3 (see FIG. 3) on each inner wall 42 on the rear side of the rocker portion 36 from each inner wall 45 and each center side wall 49 of the inner rear wall 56. 5) and the ridgeline R4 (see FIG. 5) in each center side wall 46 on the rear side of the tunnel portion 38, the load can be transmitted.

  That is, the three closed cross-sectional structures (closed cross-sectional shapes) formed in the lower back portion 26 are formed continuously with the rocker portion 36 and the tunnel portion 38 of the floor portion 22, respectively. Accordingly, the load input to the lower back portion 26 is efficiently transmitted from the lower back portion 26 to the rocker portion 36 and the tunnel portion 38 of the floor portion 22 and absorbed.

  The flange 76 of the rear suspension member 72 is fastened and fixed to the joint portion 82 (joined portion 83) by bolts 84 and nuts 86. Therefore, the load transmitted to the rear suspension member 72 is also transmitted to the joint portion 82 (joined portion 83) via the flange 76 and the bolt 84 (fastener).

  Here, in the bottom groove portion 41 on the rear side of the center cross portion 60, an opening portion 41B having a tapered shape at the rear side end portion of the vehicle body is formed. Therefore, as shown in FIG. 6, the load transmitted from the vehicle body rear side to the vehicle body front side with respect to the joint portion 82 (joined portion 83) is guided and distributed to both sides in the vehicle width direction of the bottom groove portion 41. Is done. That is, the load is transmitted to the inner side walls 45 and 42 and the center side walls 49 and 46 facing each other in the vehicle width direction.

  As a result, stress concentration around the mounting holes 82A and 83A of the joint portion 82 (joined portion 83) is alleviated, and the load on the bolt 84 can be reduced. The load is efficiently applied to the rocker portion 36 and the tunnel portion 38. Well transmitted and absorbed. Therefore, deformation of the floor portion 22 can be suppressed.

  Further, in this automobile V, even if a side collision occurs, the collision load input by the collision is received (absorbed) by the center cross part 60 having a closed cross-sectional structure on the floor part 22. That is, the load input from the side of the vehicle body (outside in the vehicle width direction) is efficiently transmitted to the center cross portion 60 and absorbed. Therefore, deformation of the floor portion 22 can be suppressed.

  As described above, according to the resin body structure 10 according to the present embodiment, deformation of the underbody 12 at the time of a collision can be suppressed. That is, when the front suspension member 70 and the rear suspension member 72 are configured to be fastened and fixed to only the lower wall 32 (only one panel) of the lower panel 12L, the transmission is transmitted to the front suspension member 70 or the rear suspension member 72. The collision load thus transmitted is transmitted to the lower panel 12L, but is difficult to be transmitted to the upper panel 12U.

  However, in the resin body structure 10 according to the present embodiment, the front suspension member 70 is fastened and fixed to the joining portion 80 joined to the lower wall 32 (joined portion 81), and joined to the lower wall 32 (joined portion 83). A rear suspension member 72 is fastened and fixed to the joined portion 82. That is, the front suspension member 70 and the rear suspension member 72 are fastened and fixed to each of the portions where the lower panel 12L and the upper panel 12U are overlapped (straddling two panels).

  Therefore, the collision load transmitted to the front suspension member 70 or the rear suspension member 72 is efficiently transmitted to both the lower panel 12L and the upper panel 12U, and is effectively absorbed by the tunnel portion 38 and the rocker portion 36. Therefore, deformation of the passenger compartment (floor portion 22) at the time of a collision can be suppressed.

  The load transmitted directly from the outer front wall 48 and the inner front wall 50 (front groove portion 51) (without the bolt 84) to the joint portion 80 (joined portion 81), the outer rear wall 54 and the inner rear wall The load transmitted directly from 56 (rear groove portion 57) (without the bolt 84) to the joining portion 82 (joined portion 83) is also caused by the tapered shape of the openings 41A and 41B, respectively. ) And the tunnel portion 38 (center side wall 46).

  Further, as described above, the portion where the front suspension member 70 and the rear suspension member 72 are fastened and fixed is the portion where the two panels (the lower panel 12L and the upper panel 12U) are overlapped (the joining portion 80 and the joined portion 81, and A joining portion 82 and a joined portion 83). Therefore, the strength (rigidity) of the part can be improved, and the steering stability performance of the automobile V can be improved.

  Even if the underbody 12 is made of resin, the dash lower portion 24 and the lower back portion 26 each having three closed cross-sectional structures can function as energy absorbing members at the time of collision. Therefore, compared with the structure which adds an energy absorption member separately, the cost reduction and weight reduction of the motor vehicle V can be achieved. In particular, the upper panel 12U has openings 41A, 41B, 51A, 51B, and 57A, so that the weight can be further reduced.

  The vehicle body structure (resin body structure 10) according to the present embodiment has been described based on the drawings. However, the vehicle body structure (resin body structure 10) according to the present embodiment is not limited to the illustrated one. The design can be changed as appropriate without departing from the scope of the present invention. For example, the upper panel 12U and the lower panel 12L may be joined by fusion or welding.

  Moreover, the joining parts 80 and 82 and the joined parts 81 and 83 may be horizontal walls along the vehicle body longitudinal direction, instead of the inclined walls as shown in FIG. Further, when the joining portions 80 and 82 and the joined portions 81 and 83 are inclined walls as shown in the figure, and the flanges 74 and 76 are horizontal walls along the vehicle body front-rear direction, the flange 74 76 and brackets 81 and 83 are interposed between the front suspension member 70 and the rear suspension member 72 to the joint portions 80 and 82 (joint portions 81 and 83). It may be.

10 Resin body structure (body structure)
12 Underbody 12U Upper panel 12L Lower panel 22 Floor part 32 Lower wall 36 Rocker part 38 Tunnel part 40 Upper wall 41 Bottom groove part (groove part)
41A opening 41B opening 44 upper wall 60 center cross part (cross part)
70 Front Suspension Member 72 Rear Suspension Member 80 Joint 80A Attachment Hole 81 Joint Part 81A Attachment Hole 82 Joint Part 82A Attachment Hole 83 Joint Part 83A Attachment Hole

Claims (3)

A resin lower panel having a lower wall constituting the lower portion of the floor portion;
A tunnel portion and a rocker portion having a closed cross-sectional structure extending in the longitudinal direction of the vehicle body are respectively formed in the vehicle width direction center portion and both side portions of the floor portion so as to face the lower wall, and the tunnel portion and the rocker portion An opening having a tapered shape on the front side and the rear side of the vehicle is formed in the groove between the opening and the groove on the front side and the rear side of the opening. An upper panel made of resin having an upper wall on which a joined portion to be joined is formed;
Body structure characterized by comprising An attachment hole for attaching a front suspension member is formed in the joining portion and the joined portion on the front side of the vehicle body,
The vehicle body structure according to claim 1, wherein an attachment hole for attaching a rear suspension member is formed in the joint portion and the joint portion on the vehicle body rear side.   The said upper wall comprises the cross part of the closed cross-section structure extended in a vehicle width direction facing the said lower wall in the vehicle body front-back direction middle part of the said floor part, The Claim 1 or Claim characterized by the above-mentioned. 2. The vehicle body structure according to 2.

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