JP5125928B2 - Body structure - Google Patents

Description

  The present invention relates to a vehicle body structure of an automobile, and more particularly to a vehicle body structure in which a crash can is provided between a side frame and a bumper.

  Conventionally, a crash can (crash box), which has lower rigidity than the side frame, is provided between the end of the side frame that extends in the longitudinal direction of the vehicle and the bumper that extends in the vehicle width direction. Techniques for absorbing initial collision energy are known.

  In addition, a technique for absorbing collision energy by buckling deformation of the side frame itself without using a crash can has been proposed (Patent Document 1).

  A relatively thin steel plate is used for the side frame to form a closed cross-sectional structure having a cross shape, and convex beads and concave beads are formed on the wall surface.

By doing so, it is possible to make it difficult to bend the side frame while increasing the amount of energy absorption at the 12 corners in the event of a vehicle collision, and to perform stable bellows-like buckling deformation starting from the bead. Yes.
JP-A-8-337183

  When the automobile collides, the load is applied to the bumper. However, the direction of the action is not uniform. For example, the bumper is pushed up, laterally displaced, or twisted.

  Therefore, in order to effectively exhibit the function of the crash can, it is preferable that the energy is appropriately transmitted to the crash can regardless of the load in any direction applied to the bumper.

  The present invention has been made in view of such a point, and the object of the present invention is to ensure that the load applied to the bumper at the time of a vehicle collision is properly transmitted to the crash can and the crash can can effectively absorb the collision energy. There is to do.

  In order to achieve the above object, in the present invention, the crash can is formed into a substantially cross-shaped cross section having four protrusions, and a protrusion having a U-shaped cross section is formed on the bumper. The parts were joined so as to be wrapped by the four protrusions of the crash can.

  Specifically, the present invention is a vehicle body structure in which a crash can is provided between an end portion of a side frame extending in the front-rear direction of the vehicle and a bumper beam extending in the vehicle width direction. It has a substantially cross-shaped cross section and is connected to the end of the side frame so as to extend in the vehicle front-rear direction with its four projecting portions directed in the vehicle up-down, left-right direction, It has a ridge that protrudes in a U-shaped cross section on the frame side and extends in the vehicle width direction, and the upper and lower protrusions on the bumper beam side of the crush can extend in the longitudinal direction of the vehicle so as to protrude, The left and right protrusions of the crush can are respectively joined to the top surface of the protrusion, and the upper and lower protrusions of the crush can are respectively provided on the upper and lower surfaces of the protrusion so as to accommodate the protrusion. It is characterized by being engaged.

  According to the present invention having such a configuration, the upper and lower protrusions of the crush can having a substantially cross-shaped cross section are joined so as to sandwich the upper and lower surfaces of the protrusion extending in the vehicle width direction, and the left and right protrusions are the protrusions. Because it is bonded to the top surface of the bumper beam, it is regulated by the left and right protrusions even if a load that shifts laterally is applied to the bumper beam, and even if a load that pushes up or pulls down is applied to the bumper beam Regulated by the protrusion, and even if a load that twists on the bumper beam is applied, it is regulated by the upper, lower, left and right protrusions, so the load acting on the bumper beam can be efficiently transmitted to the crash can, The function of the crash can can be effectively exhibited.

  Furthermore, the said protrusion part is good to be equipped with the flat plane part orthogonal to the buckling axis | shaft of the said crash can in the part joined to the said crash can at the top surface at least.

  If it does so, the load which acts on a bumper beam can be made to act with balance in the vehicle width direction of a crash can, and the stable buckling deformation of a crash can can be produced with high precision.

  In that case, it is preferable to form a plurality of beads having a bulging shape or a concave shape at a portion of the crush can that is a predetermined distance away from the plane portion.

  By doing so, it becomes easy for the bead to be deformed so as to be the starting point at the time of buckling deformation of the crash can, or to be deformed to retract inside, leading to stable buckling deformation of the crash can. And collision energy can be effectively absorbed.

  Specifically, the crush can is composed of two element members having a convex cross section with an open bottom surface, and each element member includes a first wall portion extending along the buckling axis and one end of each element member. A pair of second wall portions extending substantially perpendicularly to both sides of the first wall portion, and a pair of third wall portions each having one end continuing to the other end of the second wall portion and extending substantially vertically A pair of fourth wall portions each having one end connected to the other end of each of the third wall portions and extending substantially vertically, and each element member is butted against each other from the fourth wall portion side. The fourth wall portions are joined to each other, and the bead is formed only on the first wall portion and the pair of third wall portions.

  By doing so, the bead can be formed easily and the productivity is excellent, and the crash can can be buckled and deformed in a more stable state and the collision energy can be absorbed more effectively. it can.

  Furthermore, in this case, the fourth wall portion is joined by spot welding performed at intervals in a plurality of positions in the front-rear direction of the vehicle, and in the front-rear direction of the vehicle, the beads are joined by the spot welding adjacent to each other. It is preferable to set so as to be located between the two.

  Then, when the fourth wall portion is deformed, it is guided to the beads formed on the third wall portions on both sides thereof, and the portion between the two beads is easily deformed, but the portion is deformed. Since it is provided so as to avoid difficult joint parts, stable buckling deformation of the part can be led without being substantially affected by spot welding.

  And it is more preferable that the joint part by the spot welding is set so as to be located between the bellows-shaped buckling deformation peak and valley starting from the bead.

  By doing so, since a relatively large deformation of the crash can occurs while avoiding the joint portion by spot welding, a stable buckling deformation of the crash can can be led almost without being affected by the spot welding.

  As described above, according to the present invention, the load applied to the bumper at the time of a vehicle collision can be appropriately transmitted to the crash can, and the crash can is appropriately buckled and deformed by the action of the load. The energy can be absorbed effectively.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. It should be noted that the following description of the preferred embodiment is merely illustrative in nature, and is not intended to limit the present invention, its application, or its use.

  FIG. 1 shows a main part of an automobile (vehicle) to which the vehicle body structure of the present invention is applied. This figure shows a vehicle body structure at the right front portion of the automobile, in which a side frame 1 extending in the front-rear direction on the right side of the automobile, a bumper beam 2 extending in the vehicle width direction on the front side of the automobile, a crash can 3 and the like are provided. ing.

  A side frame (not shown) is also provided at the left front portion of the automobile, and an engine room 5 is formed between them. In the engine room 5, an engine unit 6 composed of auxiliary equipment such as an engine main body and various pumps is mounted in a state of being close to the bumper beam 2 and the side frame 1. The front wheel 7 is located outside the side frame 1 in the vehicle width direction.

  Since the left and right vehicle body structures of the front part of the vehicle are the same except for the point of being symmetrical, the description of the left front part of the vehicle is omitted in the following description. Further, the directions such as front and rear indicate directions such as the front and rear of the automobile shown in FIG. 1 unless otherwise specified.

{Bumper Beam}
As shown in FIG. 2, the bumper beam 2 is formed in a closed cross-sectional structure by joining a beam plate 31 and a beam member 32 in order to enhance rigidity.

  Specifically, the beam plate 31 is made of a strip-shaped steel material extending in the vehicle width direction. On the other hand, the beam member 32 is made of a strip obtained by pressing a steel material, and has a projecting portion 33 that protrudes in a U-shaped cross section and extends in the vehicle width direction.

  That is, as shown in detail in FIG. 7, the beam member 32 includes a top surface portion 32a extending in the vehicle width direction and a pair of protrusions extending substantially vertically with one end connected to the top and bottom sides of the top surface portion 32a. The side surface portions 32b and 32b and a pair of flange surface portions 32c and 32c projecting outward in a substantially vertical manner connected to the other ends of the projecting side surface portions 32b and 32b, respectively. It is joined to the beam plate 31 by welding. The beam member 32 will be described later separately.

{Side frame}
As shown in FIGS. 2 and 3, the side frame 1 is formed by pressing a relatively thick steel plate, and an inner member 41 positioned on the inner side in the vehicle width direction and positioned on the outer side in the vehicle width direction. And an outer member 42. The side frames 1 are formed in a closed cross-section structure by joining the flanges formed respectively above and below by spot welding.

  The side frame 1 has a vertically long, substantially rectangular cross section whose vertical dimension is slightly longer than the width dimension, and on both side surfaces on the front end side, a U-shaped band-shaped protrusion 43 extending in the front-rear direction is formed. The side frame 1 has a posture support portion 45 having a substantially cross-shaped cross section at the front end portion thereof.

{Fixed plate, mounting plate}
A fixing plate 8 having bolt holes 8a formed at four corners is joined to the front end of the posture support portion 45 of the side frame 1 so as to face the front. On the front surface of the fixed plate 8, a substantially rectangular mounting plate 9 having bolt holes 9a formed at the four corners thereof is disposed oppositely. The mounting plate 9 and the fixing plate 8 are fixed by fastening bolts B inserted through the overlapping bolt holes 8a and 9a with nuts.

  The crash can 3 is joined to the front surface of the mounting plate 9 so as to absorb and mitigate the impact when the automobile collides from the front.

{Crash Can}
As shown in FIGS. 3 to 5, the crash can 3 has a substantially cross-shaped cross section, and the front and rear of the vehicle with the four projecting portions 3 a, 3 a, 3 b, and 3 b facing in the vertical and horizontal directions of the vehicle. The one end is connected to the front end of the side frame 1 via the fixed plate 8 and the mounting plate 9, and the other end is connected to the end of the bumper beam 2.

  As shown in FIG. 6, the crash can 3 is composed of two element members 50 and 50 having substantially the same shape formed by pressing a relatively thin steel plate. These element members 50 and 50 have a convex cross section with their bottom surfaces open, and the crash can 3 is formed by abutting and joining these bottom surface sides to each other.

  Specifically, each element member 50 includes a band-shaped first wall portion 51 extending along the buckling axis P, and a pair of ends that extend substantially opposite to each other on both sides of the first wall portion 51. Second wall portions 52, 52 and a pair of third wall portions 53, 53 each having one end connected to the other end of each second wall portion 52 and extending substantially perpendicularly to each other, and each one end thereof It has a pair of 4th wall parts 54 and 54 which continue to each other end of the 3rd wall part 53, and oppose substantially perpendicularly to the other side of the 1st wall part 51. As shown in FIG.

  In the cross-sectional view, the length of each wall portion is set to be shorter than that of the first wall portion 51 in the second wall portion 52 and the third wall portion 53 is substantially equal to the length of the first wall portion 51. In addition, the lengths of the fourth wall portions 54, 54 in which the element members 50 constituting the projecting portion 3a are combined are set to be the longest compared to the others.

  Then, the tip portions of the fourth wall portion 54 of each element member 50 are overlapped with each other, and spot welding is performed at predetermined intervals at a plurality of locations in the buckling axis P direction (seven locations in this embodiment). The element member 50 is joined to form a crush can 3 having a substantially cross-shaped cross section (a joint portion by spot welding is indicated by a symbol S).

  In this embodiment, the crush can 3 formed in this way has a pair of projecting portions 3a, 3a with the top surfaces of the two joined fourth wall portions 54, 54 in the vertical direction, and the first wall portion 51 at the top. A pair of protrusions 3b, 3b serving as surfaces are joined to the mounting plate 9 so as to face in the left-right direction.

  A buckling axis P passing through the center in the longitudinal direction of the crash can 3 is orthogonal to the flat front surface (mounting surface 9b) of the mounting plate 9 and overlaps with an axis passing through the center in the longitudinal direction of the posture support portion 45 of the side frame 1. Is set to The crash can 3 is buckled and deformed in the most balanced manner with respect to the compressive load in the buckling axis P direction so that the energy can be effectively absorbed. Therefore, such a load easily acts on the crash can 3. So as to support.

  On the other hand, the front end side of the crash can 3 joined to the bumper beam 2 is also devised so as to effectively receive the load acting on the bumper beam 2, and is joined to the bumper beam 2 so as to accommodate the protrusion 33. ing.

  That is, as shown in FIGS. 3 to 5, the upper and lower protrusions 3 a and 3 a on the bumper beam 2 side of the crash can 3 are extended so as to protrude forward, and the front end edges of the beam members 32 It has the front extension parts 55 and 55 which contact | abut to the protrusion side part 32b and the flange surface part 32c of the protrusion part 33. FIG. The left and right protrusions 3 b and 3 b are formed so that the front end edges thereof are in contact with the top surface part 32 a of the protrusion 33 of the beam member 32.

  The top surface portion 32 a of the beam member 32 is a flat surface, and the top surface portion 32 a is set to be orthogonal to the buckling axis P of the crash can 3. The vertical width dimension of the top surface portion 32 a is set to be larger than the vertical width dimensions of the left and right protrusions 3 b and 3 b of the crash can 3, that is, the width dimension of the first wall portion 51 in this embodiment. In addition, the flat surface (plane part) of the top surface part 32a should just be formed in the part joined to the crush can 3 at least.

  Then, as shown in FIG. 7, the front end portion of the crash can 3 is fitted into the bumper beam 2, and fillet welding is performed along the front end edge of the crash can 3 to join the crash can 3 and the bumper beam 2 together. Has been.

  By doing so, the left and right projecting portions 3b, 3b of the crash can 3 are fixed to the top surface portion 32a of the projecting portion 33 orthogonal to the buckling axis P, so that a load that causes lateral displacement is applied to the bumper beam 2. Even so, the left and right protrusions 3 b and 3 b of the crash can 3 are regulated, and the load is efficiently transmitted to the crash can 3. Even if a load that pushes up or pulls down the bumper beam 2 is applied, the bump can be regulated by the upper and lower protrusions 3 a and 3 a of the crash can 3, and the load is efficiently transmitted to the crash can 3. Further, even if a load that twists on the bumper beam 2 acts, the bumper beam 2 is regulated by the upper, lower, left and right projecting portions 3 a, 3 a, 3 b, 3 b, and the load is efficiently transmitted to the crash can 3.

  In other words, no matter what direction the load is applied to the bumper beam 2, the energy is appropriately transmitted to the crash can 3, so that the function of the crash can 3 can be effectively exhibited.

  In addition, since the joint portion between the top surface portion 32a of the bumper beam 2 and the left and right projecting portions 3b, 3b of the crash can 3 is perpendicular to the buckling axis P, the load acting on the bumper beam 2 is reduced. It is possible to act in a well-balanced manner inside and outside in the vehicle width direction, and stable buckling deformation of the crash can 3 can be caused with high accuracy.

  Further, in order to cause stable buckling deformation of the crash can 3 with high accuracy, the bead of the crash can 3 is devised.

  That is, as shown in FIGS. 4 and 5, a plurality of concave shapes (three in each embodiment on each side) are formed in a portion of the crash can 3 that is a predetermined distance away from the top surface portion 32 a of the bumper beam 2 in the front-rear direction. ) Beads 56, 56,.

  Specifically, a bead 56 extending in the vertical direction substantially orthogonal to the buckling axis P and having a semicircular cross section is formed only on each first wall portion 51 and each pair of third wall portions 53 and 53. ing. As shown in FIG. 5, the beads 56 are arranged in a line in a side view. These beads 56 become a starting point at the time of buckling deformation of the crash can 3 and cause a deformation such that it is retracted inside.

  The buckling deformation of the crash can 3 is such that each wall portion is folded and deformed in an accordion shape in appearance, and at this time, a portion that causes a protruding deformation in the circumferential direction of the crash can 3 (also referred to as a mountain-shaped deformation portion 57). ) And a portion (also referred to as a valley-shaped deformation portion 58) that causes retraction (see FIG. 8).

  In the case of the crush can 3 having a cross-sectional shape, the first wall portion 51 and the third wall portion are formed in this manner because the mountain-shaped deformed portion 57 and the valley-shaped deformed portion 58 are likely to be alternately and continuously generated in the adjacent wall portions. By forming the bead 56 having the same concave shape only in the portion 53, the portion of the second wall portion 52 between the bead 56 of the first wall portion 51 and the bead 56 of the third wall portion 53 is an angle-shaped deformation portion. 57 easily occurs, and stable buckling deformation can be induced around the crash can 3. Although it is more preferable to form a bead that bulges on the second wall portion 52, there is a disadvantage in that a process for that purpose is required at the time of molding.

  Further, these beads 56 are set so that the buckling deformation is not easily affected by spot welding.

  That is, the bead 56 is formed so as to avoid a joining wall formed by a pair of spot-welded fourth wall portions 54, 54. And each bead 56 is set so that it may be located between the junction site | parts S by spot welding (it is also called the junction site | part S at the end) adjacent in the front-back direction, as shown in FIG.

  The portion between the beads 56 and 56 of the third wall portions 53 and 53 on both sides of the joint wall (indicated by the mesh line in the figure) is deformed so as to be led out by the beads 56 and 56 when buckling deformation occurs. In this case, since the deformed portion is located avoiding the joint portion S that is difficult to deform, the deformation is easily generated and more stable buckling deformation can be induced.

  The joining portion S is also set so as to be positioned between the mountain-shaped deformed portion 57 and the valley-shaped deformed portion 58 in the buckling axis P direction starting from the bead 56.

  FIG. 8 schematically shows a state in which the crash can 3 is buckled and deformed by applying a load in the direction of the buckling axis P as indicated by an arrow. As shown in the figure, at the time of buckling deformation, the crush can 3 is caused not only in the circumferential direction but also in the buckling axis P direction, that is, in the front-rear direction, such that the mountain-shaped deformation portion 57 and the valley-shaped deformation portion 58 are alternately generated. Become. These relatively deformed parts are set so as to avoid the joining part S that is difficult to deform. In addition, since the generation | occurrence | production position of the buckling axis P direction of these mountain-shaped deformation | transformation site | part 57 and the valley-shaped deformation | transformation site | part 58 can be estimated from the thickness, the shape, etc. of the crush can 3, what is necessary is just to carry out spot welding.

  Therefore, the crash can 3 can exhibit its function without being substantially affected by spot welding, so that stable buckling deformation can be generated with high accuracy.

  As described above, according to the vehicle body structure of the present invention, it is possible to appropriately transmit the load applied to the bumper at the time of the vehicle collision to the crash can 3, and to effectively buckle and deform the crash can 3 and its energy. Can be absorbed.

  The vehicle body structure according to the present invention is not limited to the above-described embodiment, and includes various other configurations.

  That is, the crash can 3 may be configured such that the fourth wall 54 side faces in the left-right direction and the first wall 51 side faces in the up-down direction so that each bead 56 faces in the up-down direction.

  In the said embodiment, although the bead 56 was formed in the hollow shape, the shape bulged from the wall surface conversely may be sufficient. In that case, the portion that causes the protruding deformation at the time of buckling deformation and the portion that causes the retraction deformation are substantially reversed.

It is a top view which shows the principal part of the vehicle to which the vehicle body structure of this invention is applied. It is the schematic perspective view seen from the arrow X direction of FIG. It is the schematic perspective view which abbreviate | omitted the bumper beam and was seen from the arrow Y direction of FIG. It is a top view of a crash can. It is a side view of a crash can. FIG. 6 is a sectional view taken along line ZZ in FIG. 5. It is a schematic perspective view which shows the junction part of a crash can and a bumper beam. It is a conceptual diagram which shows the crash can at the time of buckling deformation.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Side frame 2 Bumper beam 3 Crash can 6 Engine unit 7 Front wheel 8 Fixing plate 9 Mounting plate 31 Beam plate 32 Beam member 32a Top surface part 32b Projection side part 32c Flange surface part 33 Projection part 43 Belt-like projection part 45 Posture support part 50 Element Member 51 1st wall part 52 2nd wall part 53 3rd wall part 54 4th wall part 55 Forward extension part 56 Bead P Buckling axis S Joint part by spot welding

Claims (6)

A vehicle body structure in which a crash can is provided between an end portion of a side frame extending in the longitudinal direction of the vehicle and a bumper beam extending in the vehicle width direction,
The crush can has a substantially cross-shaped cross section, and is connected to the end of the side frame so as to extend in the front-rear direction of the vehicle in a state where the four protrusions are directed in the vertical and horizontal directions of the vehicle,
The bumper beam has a ridge that protrudes in a U-shaped cross section on the side of the side frame and extends in the vehicle width direction.
The upper and lower protrusions on the bumper beam side of the crash can are extended in the front-rear direction of the vehicle so as to protrude,
The left and right protrusions of the crush can are respectively joined to the top surface of the protrusion, and the upper and lower protrusions of the crush can are respectively provided on the upper and lower surfaces of the protrusion so as to accommodate the protrusion. A vehicle body structure characterized by being joined. The vehicle body structure according to claim 1,
The ridge portion has a flat plane portion perpendicular to a buckling axis of the crush can at a portion of the top surface where the crest can be joined with the crush can. The vehicle body structure according to claim 2,
A vehicle body structure, wherein a plurality of beads having a bulging shape or a hollow shape are formed at a portion of the crush can separated from the flat portion by a predetermined distance. The vehicle body structure according to claim 3,
The crash can is composed of two element members having a convex cross section with an open bottom,
Each element member includes a first wall portion extending along the buckling axis, a pair of second wall portions each having one end connected to both sides of the first wall portion and extending substantially vertically, and each one end thereof. A pair of third wall portions extending substantially perpendicular to each other end of the second wall portion, and a pair of fourth wall portions each having one end connected to each other end of the third wall portion and extending substantially vertically; Have
Each element member is abutted with each other from the fourth wall portion side, and the respective overlapping fourth wall portions are joined together,
A vehicle body structure characterized in that the beads are formed only in the first wall portion and the pair of third wall portions. The vehicle body structure according to claim 4,
The fourth wall portion is joined by spot welding performed at intervals in a plurality of locations in the longitudinal direction of the vehicle,
A vehicle body structure, wherein the bead is set so as to be positioned between adjacent joint portions by spot welding in a longitudinal direction of a vehicle. The vehicle body structure according to claim 5,
A vehicle body structure characterized in that the joint portion by the spot welding is set so as to be positioned between a bellows-shaped buckling deformation peak and valley starting from the bead.

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