JP5180950B2 - Bumper structure - Google Patents

Description

  The present invention relates to a bumper structure that efficiently absorbs collision energy against collisions such as automobiles and trucks.

  Conventionally, bumper structures are installed at the front end and the rear end of the vehicle body in order to absorb the impact at the time of a collision between an automobile and a truck. As a result, the bumper structure absorbs the collision load at the front-rear position of the vehicle body, and mitigates the impact of the occupants and pedestrians at the time of the collision.

  Conventionally, the bumper structure includes a bumper reinforcement that extends in the width direction of the vehicle body, and a bumper stay that is fixed to the vehicle body at two locations in the width direction of the vehicle body and that fixes the bumper reinforcement. The longitudinal direction of the bumper stay extends in the longitudinal direction of the vehicle body. Further, when the bumper reinforcement and the bumper stay are deformed at the time of the collision of the automobile and the truck, the collision energy is absorbed, and the application of the impact force to the passenger or the pedestrian in the vehicle is suppressed.

  Some bumper structures have a configuration in which an intermediate member is interposed between the bumper reinforcement and the bumper stay in order to reinforce the fixing portion of the bumper reinforcement to the bumper stay (patent) References 1 to 4).

  Patent Documents 1 and 2 disclose that the members of the bumper structure are fixed with bolts and nuts.

  Patent Document 3 discloses a member in which the members of the bumper structure are joined by welding. Patent Document 4 discloses a combination of fastening between bolts and nuts and joining by welding for fixing between the members.

JP 2006-224917 A JP 2001-294106 A JP 2008-168897 A Japanese Patent Laid-Open No. 2005-67527

  However, the conventional techniques described above have the following problems. FIG. 6 is a diagram showing the bending back deformation in the conventional bumper structure 10. As shown in FIG. 6 (a), the conventional bumper reinforcement 11 is a lateral portion 11b in which the central portion in the width direction of the vehicle body extends in the width direction (lateral direction) of the vehicle body, and both ends in the width direction of the vehicle body. The portion is an inclined portion 11a inclined backward from the lateral portion 11b (in the case of a front bumper). In the case of the rear bumper, the inclined portion 11a of the bumper reinforcement 11 is inclined forward of the vehicle body from the lateral portion 11b. Thereby, the impact on the vicinity of the center in the width direction of the vehicle body is absorbed by the lateral portion 11b extending in the width direction of the vehicle body, and the impact on the end portion in the width direction of the vehicle body is absorbed by the inclined portion 11a. The bumper reinforcement 11 is fixed to the bumper stay 12 at an inclined portion 11a.

  In the bumper structure configured as described above, when a collision load is applied to the lateral portion 11b at the time of a collision, the inclined portion 11a of the bumper reinforcement is formed around the bumper stay 12 as shown in FIG. 6B. Rotational deformation occurs (hereinafter referred to as bending back deformation). At this time, a large moment is applied to the bumper reinforcement 11 in a direction in which the inclined portion 11a is returned to the lateral portion 11b side with the joint portion 12b of the bumper stay 12 on the center side in the width direction of the vehicle body as a rotation fulcrum. At this time, in order to effectively absorb the collision energy, the bumper reinforcement 11 and the bumper stay 12 may be deformed following the bending back deformation. That is, the bumper stay 11 and the bumper stay 12 are integrally deformed by, for example, the bumper stay 12 being crushed to the vehicle body side at the center in the width direction of the vehicle body, and the moment is changed between the bumper reinforcement 11 and the bumper stay 12. Absorb as a whole.

  However, in the conventional bumper structure, the bumper stay 12 and the bumper reinforcement 11 cannot be deformed integrally following the bending back deformation of the bumper reinforcement 11, and the bumper reinforcement 11 and the bumper stay 12 are not deformed. In the bumper structure 10 joined by welding, as shown in FIG. 6B, between the bumper reinforcement 11 and the bumper stay 12, or between the bumper reinforcement 11 and the intermediate member (the intermediate member is (If provided), a very large peeling load is applied to the welded portion, and the welded portion is cut leaving the joint portion 12b near the center in the vehicle body width direction. In an extreme case, the entire welded portion is broken. Therefore, effective collision energy absorption by the bumper structure 10 is not performed, and the energy absorption performance of the bumper structure is significantly deteriorated.

  In Patent Document 4, as means for solving such breakage of the welded portion and breakage of the entire welded portion, an intermediate member is provided at both ends in the longitudinal direction of the bumper reinforcement, and the bumper stay 12 of the bumper reinforcement 11 is provided. There is disclosed a technique in which fixing to the bumper reinforcement 11 is performed at both ends in the longitudinal direction, and ribs for shock absorption are provided on the intermediate member. That is, in the technique of Patent Document 4, since the bumper reinforcement 11 is fixed at both ends, the inclined portion 11a cannot be secured long in the width direction of the vehicle body, and a collision occurs at the width direction end portion of the vehicle body. However, there is a problem that the collision energy cannot be absorbed sufficiently.

  Further, the intermediate member disclosed in Patent Document 4 has a complicated structure, and therefore, there is a problem that the weight of the entire bumper structure is increased. Further, if the structure of the intermediate member is complicated, there is a problem that processing is difficult and the manufacturing cost increases both when it is manufactured by press molding and when it is manufactured by extrusion molding.

  The present invention has been made in view of such problems, and in the bumper structure, at the time of collision, the welded portion does not peel off against the bending back deformation of the bumper reinforcement, and effectively absorbs the collision energy. An object of the present invention is to provide a bumper structure that is simple and lightweight.

  The bumper structure according to the present invention is supported by two bumper stays that are fixed at two positions separated from the vehicle body in the width direction so that the longitudinal direction coincides with the longitudinal direction of the vehicle body, and the front end portion of the bumper stay. A bumper reinforcement in which the support portion is inclined with respect to the longitudinal direction of the bumper stay, and the bumper stay is interposed between a tip portion of the bumper stay and the support portion of the bumper reinforcement. The front end of the bumper stay has a first end surface on the center side in the width direction of the vehicle body and a second end surface on the outer side in the width direction, and the second end surface is the first end surface. The intermediate member is bent with respect to one end face and is inclined following the inclined portion of the bumper reinforcement, and the intermediate member includes the inclined portion of the bumper reinforcement and the bumper reinforcement. A first portion overlaid on the second end surface of the first, a second portion overlaid on the first end surface of the bumper stay, and the first portion and the second portion in communication with the first portion and the second portion. And a third portion constituting one side of a triangle together with the portion, and a portion of the intermediate member on the center side in the vehicle body width direction from the position where the second portion intersects the bumper reinforcement A portion of the first portion that is fixed by welding and overlapped with the second end surface of the bumper stay is not fixed to the bumper reinforcement, and is overlapped with the second end surface of the bumper stay of the first portion of the intermediate member. The portion to be fixed is fixed to the second end surface by welding, and the second portion is fixed to the first end surface of the bumper stay by welding.

  In the above-described bumper structure, it is preferable that the position where the second portion and the third portion of the intermediate member intersect is closer to the center in the width direction of the vehicle body than the first end surface of the bumper stay.

  In the above-described bumper structure, for example, the bumper reinforcement has a square tube shape having an upper surface, a lower surface, and side surfaces, and the welded portion between the first portion and the bumper reinforcement is an upper surface and a lower surface of the bumper reinforcement, respectively. And a corner of the first portion. In addition, the welded portion between the first portion and the bumper reinforcement may be an upper surface, a lower surface, a side surface of the bumper reinforcement, and a corner portion of the first portion.

  The boundary position between the first end surface and the second end surface is preferably within a range of 30% or less of the width of the bumper stay in the width direction of the vehicle body from the central axis of the bumper stay.

  In the above-described bumper structure, the intermediate member is, for example, an extruded shape member in which the first portion, the second portion, and the third portion are integrally formed.

  The bumper reinforcement, the bumper stay, and the intermediate member are made of, for example, a JIS7000 series aluminum alloy.

  In the bumper structure of the present invention, the front end portion of the bumper stay has a first end surface on the center side in the width direction of the vehicle body and a second end surface on the outer side in the width direction of the vehicle body, and the second end surface is relative to the first end surface. The bumper stay is bent and inclined according to the inclined portion of the bumper reinforcement, and the intermediate member is formed in accordance with the shape of the bumper stay and the bumper reinforcement and is fixed to the bumper stay. Of the first portion of the intermediate member, a portion on the center side in the vehicle body width direction from the position where the second portion intersects is fixed to the bumper reinforcement by welding, and is overlapped with the second end surface of the bumper stay in the first portion. The part is not fixed to the bumper reinforcement. Thereby, the peeling load does not act on the welded portion where the intermediate member 13 is fixed to the bumper reinforcement 11, and the welded portion does not peel off. In addition, since the moment due to the load at the time of collision is applied to the center in the width direction of the vehicle body with the boundary between the first end face and the second end face as the rotation fulcrum, the collision energy is effectively reduced by the bumper reinforcement and the bumper stay. It can be absorbed and is highly safe.

  Further, the intermediate member has a simple structure. Therefore, the bumper structure of the present invention is lightweight and does not increase its manufacturing cost. And since each member is fixed only by welding, there is no need to drill holes in the bumper structure, the manufacturing process of the bumper structure can be simplified, and the entire bumper structure The weight of the can be reduced.

It is a partial top view which shows the bumper structure which concerns on embodiment of this invention. It is a perspective view which similarly shows a bumper structure. It is the perspective view which similarly looked at the bumper structure from the bumper stay side. It is a perspective view which shows the static crushing test apparatus of a bumper structure. It is a perspective view which shows the deformation | transformation state after the bending back deformation | transformation in the bumper structure of this invention. It is a top view which shows the conventional bumper structure.

  Hereinafter, embodiments of the present invention will be specifically described with reference to the accompanying drawings. First, the configuration of the bumper structure will be described. FIG. 1 is a partial plan view showing a bumper structure according to an embodiment of the present invention, and FIG. 2 is a perspective view showing the bumper structure. As shown in FIG. 1, the bumper structure 1 according to the present embodiment includes a bumper reinforcement 11, a bumper stay 12, and an intermediate member 13 interposed between the bumper reinforcement 11 and the bumper stay 12. Has been.

  The bumper reinforcement 11 extends so that a hollow member made of, for example, an aluminum alloy material has a longitudinal direction in the width direction of the vehicle body. At both ends in the longitudinal direction, the inside of the vehicle (in the case of a front bumper, the rear side of the vehicle body, In the case of the rear bumper, an inclined portion 11a bent, for example, by 10 to 20 degrees toward the front side of the vehicle body is formed. The bumper reinforcement 11 is fixed to the tip of the bumper stay 12 via the intermediate member 13 in the vicinity of the central portion of the inclined portion 11a. Hereinafter, a portion parallel to the width direction of the vehicle body located between the inclined portions 11a of the bumper reinforcement 11 is referred to as a lateral portion 11b.

  The bumper reinforcement 11 is made of, for example, a cylindrical member having a rectangular cross section, and is an extruded shape made of, for example, an aluminum alloy. The bumper reinforcement 11 is formed by bending the aluminum alloy plate material three times or four times and butting both ends of the plate material so as to have a rectangular cross section, and then joining the butted portions by welding, for example. It may be molded. In the present embodiment, the bumper reinforcement 11 is an aluminum alloy material, but may be formed of a steel material. In this case, the plate material is bent a plurality of times as in the case of the above-described aluminum alloy material. It may be formed by welding and joining the butt portion, considering the formability, after bending the plate material twice, place the U-shaped cross-section, It may be formed into a cylindrical member having a rectangular cross section by welding between each other at the butting portion. In addition, the bumper reinforcement 11 can be provided with one or a plurality of ribs inside the hollow as necessary, and the bumper reinforcement 11 is reinforced by the ribs to absorb the collision energy at the time of collision. Can be carried out effectively. In this case, the rib shape has, for example, an I-shaped cross section. Further, in the present embodiment, the bumper reinforcement 11 is configured by one cylindrical member, but the bumper reinforcement 11 may be configured by a plurality of cylindrical members. In this case, a plurality of cylindrical members are arranged side by side in the vehicle body front-rear direction and / or the vertical direction, and adjacent cylindrical members are joined by, for example, welding.

  Like the bumper reinforcement 11, the bumper stay 12 is made of, for example, an aluminum alloy or a steel material, and is formed in a cylindrical shape so as to open in the front-rear direction of the vehicle body. The bumper stay 12 is provided with a flange 12a at one end, and is fixed at two positions separated in the width direction with respect to the vehicle body by the flange 12a so that the longitudinal direction coincides with the longitudinal direction of the vehicle body. The other end of the bumper stay 12 is cut out along the inclination of the inclined portion 11a of the bumper reinforcement 11 in a plan view on the outer side in the vehicle body width direction. A first end surface 12c on the center side in the width direction and a second end surface 12d on the outer side in the vehicle body width direction following the inclined portion 11a of the bumper reinforcement 11 are formed. And in this 1st end surface 12c, the 2nd member 13b of the intermediate member mentioned later is joined by welding, and the 1st member 13a of the intermediate member is joined by welding in the 2nd end surface. For example, as shown in FIG. 1, the boundary between the first end surface 12c and the second end surface 12d is located within a range within 30% of the width W of the bumper stay 12 from the center l of the bumper stay 12 in the width direction of the vehicle body. In the present embodiment, the boundary between the first end face 12c and the second end face 12d is the center l of the bumper stay 12. As with the bumper reinforcement 11, the bumper stay 12 can be reinforced by providing one or more ribs inside the hollow.

  The flange 12a provided at one end of the bumper stay 12 is a plate material having a plate thickness of 3 to 5 mm, for example, and is joined to the bumper stay 12 by welding, for example. The flange 12a is provided with, for example, four bolt holes through which the bolts are inserted. The bolts are inserted into the bolt holes and fastened to the vehicle body, or stud bolts provided in advance on the vehicle body are connected to the bolts of the flange 12a. The bumper stay 12 supports the entire bumper structure 1 by fastening the nut and fixing the bumper structure 1 to the vehicle body after passing through the hole. The cross-sectional shape of the bumper stay 12 is formed to be a circle, a rectangle, or a polygon, and as shown in FIG. Thereby, the impact resistance in the longitudinal direction of the vehicle body is ensured by strengthening the strength against the compressive force in the central axis direction of the cylindrical body.

  The intermediate member 13 is made of an aluminum alloy or steel plate material. In the present embodiment, the intermediate member 13 is formed on the first member 13a that is superimposed on the inclined portion 11a of the bumper reinforcement 11 and the first end surface 12c of the bumper stay 12. It is comprised by the 3rd member 13c arrange | positioned so that one side of a triangle may be comprised by connecting the 2nd member 13b piled up and the 1st member and the 2nd member, These plate material 13a, 13b And 13c are arranged to form a truss shape. In the present embodiment, the first member 13a, the second member 13b, and the third member 13c are plate members formed by extrusion made of aluminum alloy, and the three plate members are joined together by welding, for example. However, in the intermediate member 13, the first member 13a, the second member 13b, and the third member 13c may be integrally formed, for example, as an extruded shape of an aluminum alloy. By forming the intermediate member 13 with an extruded profile, the dimensional accuracy of the intermediate member is improved, and the structure is simple and can be molded with high strength, so that collision energy can be absorbed reliably. In addition, the intermediate member 13 may be shape | molded with steel materials, and the rib for reinforcement may be provided between each member as needed.

  As described above, the first member 13 a of the intermediate member 13 is joined to the other end of the bumper stay 12, that is, the second end surface 12 d by welding on the back surface of the surface overlapped with the bumper reinforcement 11. The second member 13b is disposed so as to intersect the back surface of the first member 13a at the boundary between the first end surface 12c and the second end surface 12d of the bumper stay 12. The second member 13b is joined to the first end surface of the bumper stay 12 by welding. The third member 13c is disposed so as to communicate between the first member 13a and the second member 13b, and between the first member 13a and the third member 13c, and between the second member 13b and the third member 13c. The two are joined by welding. At this time, as shown in FIG. 1, the portion where the second member 13b and the third member 13c intersect is the width direction of the vehicle body rather than the joint portion (first end surface 12c) between the second member 13b and the bumper stay 12 It is preferable to arrange on the center side. Thus, the bumper reinforcement 11 crushes the intermediate member 13 with the moment fulcrum as the boundary between the first end surface 12c and the second end surface 12d (intersection of the first member 13a and the second member 13b). The bumper stay 12 can be buckled, and after the intermediate member 13 is crushed, the bumper stay 12 is pressed in the direction of the central axis of the bumper stay 12 to collapse the entire bumper stay 12 in the direction of the central axis. be able to.

  As shown in FIG. 3, the first member 13 a of the intermediate member 13 is located at a position where the second member 13 b intersects, that is, the first end surface 12 c of the bumper stay 12 and the second portion. It is joined to the bumper reinforcement 11 by welding at the center in the width direction of the vehicle body from the boundary with the end face 12d. At this time, the locations where the first member 13a is welded to the bumper reinforcement 11 may be corners (region B in FIG. 3) between the upper and lower surfaces of the bumper reinforcement 11 and the first member 13a. In order to improve the strength of the joint, the side surface of the bumper reinforcement 11 and the corner (region C in FIG. 3) between the first member 13a may be joined by welding.

  As described above, in the present invention, the intermediate member 13 is provided between the bumper reinforcement 11 and the bumper stay 12, and the intermediate member 13 is constituted by the first member 13a, the second member 13b, and the third member 13c. Yes. A first end surface 12 c and a second end surface 12 d are provided at the tip of the bumper stay 12. Then, the first member 13a is disposed along the bumper reinforcement 11, and the first member 13a is welded to the bumper stay 12 on the center side in the width direction of the vehicle body from the boundary between the first end surface 12c and the second end surface. The first member 13a is joined to the bumper stay 12 by welding on the outer side in the width direction of the vehicle body from the boundary between the first end face and the second end face. At this time, by providing the first member 13a, even if the first member 13a is not welded to the bumper reinforcement 11 outside the boundary between the first end surface and the second end surface in the width direction of the vehicle body, By setting the length of the first member 13a longer at the center in the width direction, the weld length can be increased and a weld portion having sufficient strength can be formed. In addition, the second member 13b is provided so as to branch from the middle of the first member 13a, the first member 13a is welded to the second end surface 12d of the bumper stay 12, and the second member 13b is welded to the first end surface 12c of the bumper stay 12. As a result, the welding length at which the intermediate member 13 is welded to the bumper stay 12 is longer than when the second member 13b is branched from the outer end of the first member 13a in the vehicle width direction. Become. As described above, in the present invention, the first end surface 12c and the second end surface 12d are provided at the tip of the bumper stay 12, and the first member 13a and the second member 13b are provided according to the tip shape of the bumper stay 12. There is a secondary effect that the weld length between the bumper stay 12 and the intermediate member 13 can be increased.

  When the bumper reinforcement 11, the bumper stay 12 and the intermediate member 13 constituting the bumper structure 1 are made of an aluminum alloy, it is preferable to use a JIS 7000 series aluminum alloy. Thereby, not only the intensity | strength of the bumper structure 1 can be raised, but when manufacturing the bumper structure 1, the welding construction property between each member can be improved. In addition to the JIS 7000 series aluminum alloy, JIS 2000 series, 3000 series, 5000 series and 6000 series aluminum alloys can be used as the aluminum alloy.

  The welded portion that joins the members may be formed with a continuous bead or an intermittent bead. In the case where the welded portion is formed with intermittent beads, the size of the weld distortion generated in the welded portion can be reduced. However, when the weld is formed with intermittent beads, the pitch between the beads is preferably 30 mm or more. As a welding method, in addition to MIG welding, TIG welding, arc welding, and laser welding, hybrid welding in which laser welding and arc welding are combined can be employed.

  Next, operation | movement of the bumper structure of this invention is demonstrated. When an automobile or a truck equipped with the bumper structure of the present invention collides with another automobile or an obstacle, the collision object first collides with the bumper reinforcement 11. When the position where the collision object collides is the lateral portion 11b of the bumper reinforcement 11, the lateral portion 11b of the bumper reinforcement 11 is pressed toward the inside of the vehicle body. Therefore, the bumper reinforcement 11 having a longitudinal direction in the width direction of the automobile has its end rotated in the direction of the outside of the vehicle body with the bumper stay 12 as a support shaft, that is, the inclination of the inclined portion 11a toward the lateral portion 11b A rotational moment is applied in the returning direction. As a result, the inclined portion 11a of the bumper reinforcement 11 undergoes bending back deformation due to the applied rotational moment.

  In the conventional bumper structure 10 as shown in FIG. 6, the moment rotation fulcrum at the time of bending back deformation is the center in the vehicle width direction of the bumper stay 12, so that the inclined portion 11 a of the bumper reinforcement 11 has A large moment is applied starting from the joint 12b near the center of the bumper stay 12 in the vehicle width direction. Therefore, a large peeling load is applied to the welded portion between the bumper reinforcement 11 and the bumper stay 12, and the welded portion is cut or, in an extreme case, the entire welded portion is broken. In this case, the bumper reinforcement 11 and the bumper stay 12 cannot be integrally deformed, and the bumper structure 10 does not absorb the collision energy effectively, and the energy absorption performance of the bumper structure. Is significantly reduced.

  On the other hand, in the present invention, of the first member 13a of the intermediate member 13, only the center in the width direction of the vehicle body is welded to the bumper reinforcement 11 from the position where the second member 13b intersects the first member 13a. Therefore, the moment rotation fulcrum at the time of bending back deformation is the boundary between the first end surface 12c and the second end surface 12d of the bumper stay 12, and the moment rotation fulcrum is the central axis of the bumper stay 12 and its vicinity. It is in. That is, the first member 13a has a bumper reinforcement at an intersection with the second member 13b, that is, a region on the center side in the width direction of the vehicle body from the boundary between the first end surface 12c and the second end surface 12d of the bumper stay 12. 11 is joined by welding. The first member 13 a is not fixed to the bumper reinforcement 11 at a portion overlapping the second end surface 12 d of the bumper stay 12. By configuring the bumper structure in this way, the moment due to the load applied to the center in the width direction of the vehicle body at the time of collision is applied using the boundary between the first end surface 12c and the second end surface 12d of the bumper stay 12 as a rotation fulcrum. Thus, the moment acts on the bumper reinforcement 11 in the direction of pressing the bumper reinforcement 11 toward the bumper stay 12 at the center in the width direction of the vehicle body from the moment rotation fulcrum. As a result, a pressing force acts on the welded portion where the intermediate member 13 is fixed to the bumper reinforcement 11 so that no peeling load acts on the welded portion, and no peeling of the welded portion occurs.

  When the stress applied to the bumper stay 12 increases, the bumper stay 12 starts to bend and starts to buckle mainly from the region of the first end face 12c. As a result, the bumper stay 12 actively absorbs collision energy. That is, in the present invention, the load applied to the bumper reinforcement 11 is efficiently transmitted to the bumper stay 12 via the intermediate member 13 at the welded portion on the center side in the width direction of the vehicle body from the moment rotation fulcrum. After the bumper stay 12 is buckled, the bumper stay 12 can be crushed so that the deformation of the bumper stay 11 can follow the deformation of the bumper reinforcement 11, and the bumper reinforcement 11 and the bumper stay 12 can be integrally deformed, resulting in an effect. The collision energy can be absorbed. At this time, even if the position of the boundary between the first end surface 12 c and the second end surface 12 d is not the center of the bumper stay 12, the boundary is 30 of the width W of the bumper stay 12 from the center of the bumper stay 12 in the width direction of the vehicle body. If it is within the range of%, the collision energy can be absorbed more effectively by the bumper stay 12.

  Further, for example, the portion of the intermediate member 13 where the second member 13b and the third member 13c intersect is more central in the width direction of the vehicle body than the joint portion (first end surface 12c) between the second member 13b and the bumper stay 12. If provided, the bumper reinforcement 11 more effectively transmits the impact at the time of collision to the bumper stay 12, and the deformation of the bumper reinforcement 11 and the bumper stay 12 absorbs the collision energy more effectively. be able to. That is, since the portion where the second member 13b and the third member 13c intersect is closer to the center in the width direction of the vehicle body than the first end surface 12c, the intermediate member 13 is easily deformed. The bumper stay 12 can be buckled while the intermediate member 13 is crushed. After the intermediate member 13 is crushed, the bumper reinforcement 11 presses the bumper stay 12 in the direction of the central axis of the bumper stay 12, and crushes the entire bumper stay 12 in the direction of the central axis, for example, in a bellows shape. be able to.

  As described above, according to the present invention, collision energy can be effectively absorbed by the bumper reinforcement 11 and the bumper stay 12. Therefore, it is possible to suppress the impact force from being applied to the passengers or pedestrians in the vehicle at the time of the collision of the automobile, and to improve the safety of the passengers and the pedestrians.

  In the present embodiment, the bumper reinforcement 11 has been described as a cylindrical member having a rectangular cross section. However, the bumper reinforcement 11 may not have a rectangular cross section, for example, may be formed in a cylindrical shape. Good. Alternatively, the cross section on the inner side of the vehicle body may be rectangular so that it can be easily fixed to the bumper stay 12 and the intermediate member 13, and a fillet may be provided on the outer side of the vehicle body to make the contact pressure to the collision object uniform.

  Further, the bumper stay 12 is not limited to a rectangular tube shape or a cylindrical shape, and the cross-sectional shape thereof may be a polygonal shape such as a hexagonal shape or an octagonal shape.

  Hereinafter, the effect of the bumper structure of the present invention will be described in comparison with comparative examples. In this example, first, a bumper reinforcement composed of a JIS7000 series alloy (Zn: 6.5 mass%, Mg: 0.8 mass%, Cu: 0.15 mass%, the balance being aluminum and inevitable impurities), The bumper stay and the intermediate member were formed by extrusion. And about the bumper reinforcement, the inclination part was processed into the both ends of a longitudinal direction by giving a bending process.

  In this embodiment, the bumper reinforcement has a rectangular cross section (width 70 mm, height 80 mm, wall thickness 2 mm), and a single rib 2 mm thick is provided horizontally in the middle of the hollow member. Thus, the cross-sectional shape was processed into a Japanese character shape. The inclined portion of the bumper reinforcement is obtained by bending a 300 mm section at the end of the bumper reinforcement in the longitudinal direction of the vehicle by 15 degrees.

  The bumper stay is processed into a hollow extruded shape having a rectangular cross section (width 80 mm, height 100 mm, wall thickness 2 mm) to a length of 80 mm. Like the bumper reinforcement, inside the hollow member, One rib with a thickness of 2 mm was provided in the middle part to make a cross-sectional shape. A flange made of 7000 series aluminum alloy was joined to one end of the bumper stay by welding. Further, the other end of the bumper stay was cut out in a range of 40 mm in the width direction and 10.7 mm in height. Thus, the first end surface and the second end surface were provided at the tip of the bumper stay.

  The intermediate member was formed by extrusion so that the first member, the second member, and the third member had a thickness of 3 mm, and the three plate members were arranged in a truss shape. In addition, the dimension of the intermediate member was 110 mm in width and 130 mm in length for the first member, 110 mm in width and 55 mm in length for the second member, and 110 mm in width and 14.2 mm in length for the third member. And the crossing part (branch part) of the 1st member and the 2nd member shall be 65 mm from the edge part of the 1st member, and the crossing part of the 1st member and the 3rd member is a bifurcation part of the 2nd member The crossing portion between the second member and the third member was set at a position 55 mm from the branch portion of the second member.

  The bumper reinforcement, the intermediate member, and the bumper stay created in this way were arranged in this order and joined by MIG welding. The bumper stay and the intermediate member were joined by MIG welding all around. As a result, the intersection of the second member and the third member in the intermediate member is disposed closer to the center in the width direction of the vehicle body than the joint between the second member and the bumper stay. In addition, the bumper reinforcement and the intermediate member are the upper surface, the lower surface, and the side surface of the bumper reinforcement in the range of the branched portion of the intermediate member, that is, in the range from the intersection of the first member and the second member to the center in the width direction of the vehicle body. And the first member were joined by MIG welding.

  As shown in FIG. 6A, the bumper structure of the comparative example is not cut out at the tip of the bumper stay 12, and an intermediate member is not provided between the bumper reinforcement 11 and the bumper stay 12. In addition, the entire circumference welded between the bumper reinforcement and the bumper stay by MIG welding was used.

  The bumper structures of these examples and comparative examples were installed in the static load device 4 shown in FIG. The flange 12a of the bumper stay 12 is fixed to the pedestal 4b of the static load device 4 with bolts, so that the load is evenly distributed in the longitudinal direction in the range where the bumper reinforcement 11 is not bent (lateral portion 11b). Then, the barrier 4a of the static load device 4 was pressed and the deformation of the bumper structure was observed. The processing speed of the barrier 4a was 30 mm / min (average speed).

  As a result, both the bumper structure of the example and the bumper structure of the comparative example were bent back. In the bumper structure of the embodiment, as shown in FIG. 5, the first member 13 a of the intermediate member 13 is near the intersection of the second member 13 b, that is, the first end surface 12 c and the second end surface 12 d of the bumper stay 12. Bending around the boundary of the first end surface 12c and the second end surface 12d with respect to the center in the width direction of the vehicle body with the vicinity of the intersection of the first member 13a and the second member 13b as the fulcrum Following the deformation, the entire intermediate member 13 was deformed so as to rotate. As a result, the second member was pressed against the bumper stay 12, and the bumper stay 12 buckled in the region A shown in FIG. Accordingly, it was found that the energy at the time of collision can be effectively absorbed by the deformation of the bumper reinforcement 11 and the bumper stay 12.

  On the other hand, as shown in FIG. 6B, the bumper structure of the comparative example has a welded portion formed by bending back deformation of the bumper reinforcement 11 with the joint portion on the center side in the width direction of the vehicle body as a moment rotation fulcrum. Broke momentarily.

  As described above, with the bumper structure having the configuration of the present invention, the collision energy can be effectively absorbed by the bumper stay at the time of the collision without biasing the collision energy only to the bumper reinforcement. Therefore, when the bumper structure of the present invention is installed in an automobile or a truck, the impact force is suppressed from being applied to passengers or pedestrians in the vehicle, and the safety of passengers and pedestrians is improved. Can do.

  Further, the bumper structure of the present invention has a simple structure. Therefore, the manufacturing cost is low without increasing the weight of the entire bumper structure. And if fixing between each member is performed only by welding, there is no need to drill holes in the bumper structure, so the manufacturing process of the bumper structure can be simplified. It is also possible to reduce the weight.

DESCRIPTION OF SYMBOLS 1, 10: Bumper structure, 11: Bumper reinforcement, 11a: Inclined part, 11b: Lateral part, 12: Bumper stay, 12a: Flange, 12b: Vehicle body center side junction part, 12c: 1st end surface, 12d: 1st 2 end faces, 13: intermediate member, 13a: first member, 13b: second member, 13c: third member, 2: welded part, 4: static load device, 4a: barrier, 4b: pedestal

Claims (7)

Two bumper stays fixed at two positions separated from the vehicle body in the width direction so that the longitudinal direction thereof coincides with the longitudinal direction of the vehicle body, and supported by the tip portion of the bumper stay, the support portion is supported by the bumper stay. A bumper reinforcement that is inclined with respect to the longitudinal direction, and has an intermediate member interposed between a front end portion of the bumper stay and a support portion of the bumper reinforcement, The front end portion of the bumper stay has a first end surface on the center side in the width direction of the vehicle body and a second end surface on the outer side in the width direction, and the second end surface is bent with respect to the first end surface. The intermediate member is inclined following the inclined portion of the bumper reinforcement, and the intermediate member is overlapped with the inclined portion of the bumper reinforcement and the second end surface of the bumper stay. And a second portion overlaid on the first end surface of the bumper stay, a first portion and the second portion are connected to each other to form one side of the triangle together with the first portion and the second portion. The first portion of the intermediate member is fixed to the bumper reinforcement by welding from the position where the second portion intersects to the bumper reinforcement. Of these, the portion that overlaps the second end surface of the bumper stay is not fixed to the bumper reinforcement, and the portion of the first portion of the intermediate member that overlaps the second end surface of the bumper stay is welded to the second end surface. A bumper structure, wherein the second portion is fixed to the first end surface of the bumper stay by welding. 2. The bumper according to claim 1, wherein a position at which the second portion and the third portion of the intermediate member intersect with each other is on the center side in the width direction of the vehicle body with respect to the first end surface of the bumper stay. Structure. The bumper reinforcement has a rectangular tube shape having an upper surface, a lower surface, and side surfaces, and the welded portions between the first portion and the bumper reinforcement are corners of the upper surface, the lower surface, and the first portion of the bumper reinforcement, respectively. The bumper structure according to claim 1, wherein the bumper structure is a portion. The bumper reinforcement has a rectangular tube shape having an upper surface, a lower surface, and a side surface, and the welded portion between the first portion and the bumper reinforcement is an upper surface, a lower surface, a side surface, and the first portion of the bumper reinforcement, respectively. The bumper structure according to claim 1, wherein the bumper structure is a corner of the bumper structure. The position of the boundary between the first end surface and the second end surface is within a range of 30% or less of the width of the bumper stay in the width direction of the vehicle body from the central axis of the bumper stay. The bumper structure of any one of thru | or 4. The bumper structure according to any one of claims 1 to 5, wherein the intermediate member is an extruded profile in which the first portion, the second portion, and the third portion are integrally formed. . The weld bumper structure according to any one of claims 1 to 6, wherein the bumper reinforcement, the bumper stay, and the intermediate member are made of a JIS7000 series aluminum alloy.

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