JP2012188106A - Impact absorption member and bumper device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an impact absorption member excellent in mass production and traction characteristics when attached to a reinforcement, and a bumper device using the same.SOLUTION: The impact absorption member 1 has: a bottom 11; a flange 12; and a nearly square cylinder shape impact absorption part 13 provided between the bottom 11 and the flange 12 and formed of four sidewall surfaces 13a, 13b, 13c, 13d. The bottom 11, the flange 12 and the impact absorption part 13 are integrally formed by press-forming one sheet of an aluminum sheet material. The flange 12 has a body 12a projected from the edge of the impact absorption part 13 and an erected part 12b provided at the outer periphery of the body 12a and erected at the impact absorption part 13 side. In the bumper device 2, the bottom 11 of the impact absorption member 1 is fixed to the reinforcement.

Description

  The present invention relates to an impact absorbing member and a bumper device.

  Conventionally, bumpers are provided in front and rear of a vehicle such as an automobile in order to absorb an impact at the time of the collision of the vehicle and reduce an impact energy transmitted to the vehicle. Generally, the bumper has a resin outer cover, a reinforcement extending in the vehicle width direction, and a foamed resin that fills a gap between the outer cover and the reinforcement. The reinforcement is attached to the frame of the vehicle main body via an impact absorbing member that absorbs impact energy by buckling deformation.

  As the impact absorbing member, for example, as described in Patent Document 1 and the like, an extruded shape made of an aluminum alloy having a predetermined cross-sectional shape considering impact absorption is widely used.

  In addition, in Patent Document 2, an aluminum plate material is pressed deep-drawn to form a bottomed cylinder, and then the bottomed cylinder is axially pressed to form a spiral step on the outer wall surface. A formed shock absorbing member has been proposed.

JP 2007-30647 A JP 2007-261557 A

  However, the prior art has problems in the following points. That is, when an extruded shape is used as the impact absorbing member, three parts are required: an impact absorbing portion made of the extruded shape, a fixing member for fixing to the reinforcement, and a fixing member for fixing to the vehicle frame. It becomes. For this reason, the number of manufacturing processes such as cutting of each part and assembly by line welding (all-around welding) between the parts increase. In particular, wire welding between members increases costs. Thus, the impact-absorbing member using an extruded profile has a problem that the manufacturing process increases and the mass productivity is inferior.

  On the other hand, the impact absorbing member of Patent Document 2 needs to perform press work for forming a spiral step on the outer wall surface, in addition to the press deep drawing process for forming the bottomed cylindrical body. Therefore, it cannot be said that the advantage of the press molding which increases a manufacturing process and is excellent in mass productivity is fully utilized. Moreover, it is difficult to form a spiral stepped portion on the outer wall surface of the bottomed cylindrical body by pressing.

  Furthermore, vehicles such as automobiles may be towed. The vehicle is pulled by pulling a tow hook provided on a reinforcement in the bumper in the front direction of the vehicle (in the case of a front bumper) or in the rear direction of the vehicle (in the case of a rear bumper). Therefore, the impact absorbing member that connects the reinforcement and the frame of the vehicle body is required to be difficult to be deformed with respect to a tensile load (traction load) applied during towing. However, the shock absorbing member of Patent Document 2 does not present any means for solving such a demand.

  The present invention has been made in view of such problems, and is intended to provide an impact absorbing member excellent in traction characteristics when attached to mass production and reinforcement, and a bumper device using the same. is there.

  One aspect of the present invention is provided between a bottom portion for fixing to a reinforcement for reinforcing a bumper of a vehicle, a flange portion for fixing to a vehicle body frame, and the bottom portion and the flange portion. A substantially rectangular tube-shaped shock absorbing portion composed of four side wall surfaces, and the bottom portion, the flange portion and the shock absorbing portion are integrally formed by press-molding a single aluminum plate. The flange portion has a main body portion projecting from an edge of the shock absorbing portion, and an upright portion provided on an outer periphery of the main body portion and standing on the shock absorbing portion side. It exists in an absorption member (Claim 1).

  According to another aspect of the present invention, there is provided a reinforcement for reinforcing a bumper of a vehicle and the impact absorbing member, and the impact absorbing member has the bottom portion fixed to the reinforcement. In the bumper device (claim 6).

Since the said impact-absorbing member has the said structure, it is excellent in mass productivity and the traction characteristic at the time of attaching to a reinforcement.
Specifically, the bottom portion, the flange portion, and the impact absorbing portion are integrally formed by press-molding a single aluminum plate material. Therefore, the number of parts is reduced as compared with the case where an extruded profile is used, and manufacturing processes such as cutting of each part and assembly by wire welding of parts are not required. Further, as described in Patent Document 2, processing for forming a stepped portion on the side wall surface is not necessary. Therefore, it is excellent in mass productivity. In particular, the fact that a wire welding process is not required for forming the impact absorbing member is advantageous in terms of cost reduction.

  The flange portion has a main body portion protruding from an edge of the shock absorbing portion, and an upright portion provided on the outer periphery of the main body portion and standing on the shock absorbing portion side. Therefore, the rigidity of the flange portion can be improved, and the deformation resistance against the traction load is improved. Therefore, with the bottom part fixed to the reinforcement and the flange part fixed to the frame of the vehicle body, in the vehicle front direction (when applied to the front bumper side) or the vehicle rear direction (when applied to the rear bumper side) Even when a traction load is applied, permanent deformation is difficult and excellent traction characteristics can be exhibited.

  Since the bumper device uses the shock absorbing member, it is excellent in mass productivity and traction characteristics when towing the vehicle.

It is a perspective view which shows the structure of the impact-absorbing member in Example 1. FIG. FIG. 3 is a plan view showing a configuration of an impact absorbing member in Example 1. It is explanatory drawing which shows the structure (however, the left half at the time of applying to a vehicle front direction, ie, a front bumper side), in Example 1. FIG. It is explanatory drawing which expands and shows the cross-sectional shape of the impact-absorbing member of a bumper apparatus in Example 1. In Example 1, it is explanatory drawing which shows the cross-sectional shape of the reinforcement of a bumper apparatus. It is explanatory drawing which shows the outline of the evaluation method by simulation. It is a simulation result which shows the relationship of load point displacement-load. FIG. 6 is a perspective view illustrating a configuration of an impact absorbing member in Example 2. 6 is a plan view showing a configuration of an impact absorbing member in Embodiment 2. FIG. It is sectional drawing which shows the structure of the AA cross section in FIG. It is sectional drawing which shows the structure of the BB cross section in FIG.

  As described above, the shock absorbing member is provided between the bottom portion for fixing to the reinforcement for reinforcing the bumper of the vehicle, the flange portion for fixing to the vehicle body frame, and the bottom portion and the flange portion. And an impact absorbing portion. In the shock absorbing member, the method for fixing the bottom portion to the reinforcement and the method for fixing the flange portion to the frame of the vehicle main body are not particularly limited. Examples of the fixing method include fastening by fastening members such as bolts and nuts, mechanical joining by caulking or self-piercing rivets, friction stir welding, spot welding, and the like.

  The shape of the bottom portion is preferably a substantially square shape in view of the relationship with the edge shape on the bottom side of the substantially square cylindrical shock absorbing portion. Moreover, what is necessary is just to form a bottom part in the shape along the side wall surface arrange | positioned inside the vehicle front-back direction of the reinforcement for fixing a bottom part.

  The impact absorbing portion is formed in a substantially rectangular tube shape composed of four side wall surfaces. The four side wall surfaces are preferably flat surfaces from the viewpoint of improving press formability. At this time, the connecting portions between the side wall surfaces may be rounded so as not to have corners, or may have corners. The connecting portion is preferably rounded so as to have no corners from the viewpoint of excellent demoldability during press molding and contribution to improvement of press moldability.

  The four side wall surfaces of the shock absorbing part can be arranged so that the side wall surfaces facing each other are substantially parallel to each other. Of the four side wall surfaces, at least one side wall surface may be an inclined surface formed so as to expand from the bottom toward the flange portion toward the outside of the cylinder. For example, among the four side wall surfaces, the side wall surface arranged on the inner side in the vehicle width direction is formed so that the inner side in the vehicle width direction and the flange side expand within a range of 5 ° to 15 ° with respect to the vehicle front-rear direction. It can be an inclined surface or the like. In this case, since the balance between the initial buckling load and the prevention of the lateral collapse when receiving an impact load is excellent, in addition to the improvement of the traction characteristics, the impact absorption characteristics can be easily improved.

  The main body portion of the flange portion is formed so as to protrude from the edge of the shock absorbing portion toward the outside of the cylinder, but the protruding amount is not particularly limited. It can be adjusted to the optimum protrusion amount in consideration of the formability of the upright part, the ease of attachment to the frame, press workability and the like. The outer shape of the main body is not particularly limited, and may be a substantially polygonal shape such as a substantially rectangular shape, a substantially circular shape, or the like. The outer shape of the main body is preferably substantially rectangular from the viewpoint of ease of attachment to the frame. Moreover, when fixing a flange part to the flame | frame of a vehicle main body with a fastening member, the attachment hole which penetrates a volt | bolt can be formed in a main body part.

  The standing part of the flange part is provided on the outer periphery of the main body part and stands on the side of the shock absorbing part. The upright portion may be provided continuously over the entire outer periphery of the main body portion or may be provided so as to include a discontinuous portion. A discontinuous part can be formed from space parts, such as a notch part and a slit, for example, These can be formed 1 or 2 or more. Moreover, the standing part may be partially provided in the outer periphery of the main-body part.

  Moreover, as long as the standing part stands on the shock absorbing part side, the size of the angle formed between the main body part and the standing part is not particularly limited. The angle formed between the main body portion and the upright portion is preferably within the range of 90 ° ± 10 °, more preferably within the range of 90 ° ± 5 °, from the viewpoint that the effect of improving the rigidity of the flange portion is large. It should be inside. Moreover, the height from the main-body part of a standing part is not specifically limited, either. The height of the upright portion from the main body is preferably within a range of 5 to 25 mm, more preferably 10 to 20 mm, from the viewpoint of the effect of improving the rigidity of the flange portion and the improvement of the formability of the upright portion. It should be within the range.

  The bottom part, the flange part, and the shock absorbing part are integrally formed by press-molding a single aluminum plate. There is no seam due to caulking or joining between the bottom and the flange, or between the flange and the shock absorber. The “aluminum” referred to in the present application is a general term for metals and alloys mainly composed of aluminum, and is a concept including pure aluminum and aluminum alloys.

  As the press molding method, deep drawing can be suitably used. The thickness of the bottom part and the flange part is preferably in the range of 2 to 4 mm from the viewpoint of traction characteristics, and the thickness of the shock absorbing part is preferably in the range of 2 to 4 mm. It is good to be integrally formed from a plate material. Further, the upright portion of the flange portion may be formed by press molding such as deep drawing, or may be formed by bending after press molding. The length of the impact absorbing portion in the vehicle front-rear direction can be appropriately determined according to the distance between the reinforcement and the frame of the vehicle body.

  In the shock absorbing member, the main body portion is formed in a substantially rectangular shape having four sides substantially parallel to four sides of the intersection with the four side wall surfaces of the shock absorbing portion, and the standing portion is the main body portion. It is preferable that it is comprised from the standing piece formed in each of the four sides mutually independently (Claim 2).

  In this case, a bend margin that becomes an upright piece by bending is formed in advance on the same surface as the main body portion of the flange portion by press forming or subsequent punching processing, and the bend margin is formed after press forming. Each standing piece can be formed by bending. Since a simple bending process can be used, it is excellent in workability and can contribute to the improvement of mass productivity. Moreover, since a space part is formed between the both ends of each standing piece, it leads also to weight reduction. Moreover, since the outer shape of the main body is formed in a substantially rectangular shape having four sides substantially parallel to the four sides of the intersection with the four side wall surfaces of the shock absorbing portion, it is excellent in ease of attachment to the frame. In addition, there is an advantage that it is easy to form bolt mounting holes in an appropriate arrangement when fixing with a fastening member.

  The upright piece may be configured to bend in a direction perpendicular to the main body, or may be configured such that the tip of the upright piece is bent in a direction horizontal to the main body. When the upright piece is configured in this way, the rigidity of the flange portion can be further improved, so that it is difficult to be deformed by a traction load, and excellent traction characteristics are easily obtained.

  In the shock absorbing member, the main body has attachment holes for fixing to the frame by fastening at substantially four corners, and the length of each upright piece is determined by the distance between the centers between the attachment holes. It is preferable that the length is long (claim 3).

  The outer side is less likely to be deformed by the traction load than between the mounting holes, but the inner side is more likely to be deformed by the traction load than between the mounting holes. Therefore, when it is set as the said structure, it is excellent in the balance with the bending improvement property of an upright piece, and the rigidity improvement effect of a flange part. In addition, a bolt, a nut, etc. can be used suitably for the said fastening means. Also, each mounting hole only needs to be near the four corners of the main body, and depending on the positional relationship between the frame and the flange when mounting the frame, each mounting hole may be formed from the center of the upright piece. Permissible. Further, in this case, the “distance between the centers of the mounting holes” refers to the length when the length connecting the centers of the mounting holes is projected onto a plane parallel to the standing piece.

  In the shock absorbing member, at least one of the four side wall surfaces constituting the shock absorbing portion and at least the intersecting portion between the main body portion of the flange portion and the one or two or more beads It is preferable that a portion is formed (claim 4).

  In this case, it is possible to improve the rigidity of the intersection where a relatively large load is likely to be applied due to the traction load. Therefore, the deformation resistance against the traction load is further improved. Therefore, with the bottom part fixed to the reinforcement and the flange part fixed to the frame of the vehicle body, in the vehicle front direction (when applied to the front bumper side) or the vehicle rear direction (when applied to the rear bumper side) Even when a traction load is applied, it is more difficult to be permanently deformed, and a more excellent traction characteristic can be exhibited. Moreover, since the bead part is relatively easy to introduce into the intersection part, it is difficult to lose mass productivity.

  In the shock absorbing member, since the shock absorbing portion is composed of four side wall surfaces, there are four intersections between the side wall surface and the main body portion of the flange portion. The bead portion may be formed at any intersection. For example, when the bumper device is configured using the impact absorbing member, it may be formed at one or both of two intersecting portions that are substantially parallel to the vehicle width direction. Further, when the bumper device is configured using the impact absorbing member, it may be formed at one or both of two intersecting portions that are substantially parallel to the vehicle vertical direction. The bead portion can be appropriately formed according to the required traction load. In addition, the said bead part should just exist in the intersection part at least, and may exist in the state which a part of said bead part hooks in the side wall surface which comprises an impact-absorbing part, or the main-body part of a flange part. .

  The shape of the bead portion is not particularly limited as long as the rigidity of the intersecting portion can be improved. The bead portion can be preferably configured by plastically deforming part or all of the intersecting portion from the mountain side of the intersection portion to the valley side or from the valley side of the intersection portion to the mountain side. More specifically, for example, the bead portion can be constituted by a bulging portion that is bulged by plastic deformation of a part of the intersecting portion from the mountain side to the valley side of the intersecting portion. . The bead portion includes, for example, the intersection of the side wall surface of the shock absorbing portion and the main body portion of the flange portion, and the cut surface when cut at a surface having an angle of 45 ° with the main body portion of the flange portion, The shape may be a substantially triangular shape, a substantially semicircular shape, or the like. The bead portion having a substantially triangular cut surface can be formed relatively easily by molding or the like. Therefore, it becomes easy to contribute to the improvement of mass productivity.

  The pitch of the bead part can be appropriately set according to the length of the intersection part. The pitch of the bead portion can be selected from a range of 15 to 35 mm, for example.

In the shock absorbing member, the aluminum plate material is preferably made of a 6000 series aluminum alloy (hereinafter referred to as “6000 series alloy”).
6000 series alloys are less prone to bending cracks. Therefore, it is difficult for cracks to occur when the shock absorbing portion buckles and deforms in a substantially bellows shape, and it is difficult to deteriorate the shock absorbing characteristics. Specific examples of the 6000 series alloy include 6009, 6016, 6111, 6061, and 6063.

  When press-molding the shock absorbing member from a single aluminum plate, the shape is determined by press-molding using an aluminum plate made of an O material or a T4 material, and then heat treatment is performed so that it becomes a T6 material. preferable. The press working to the shape of the shock absorbing member in which the bottom part, the flange part, and the shock absorbing part are integrated is a strong work. Therefore, when press molding is performed using an aluminum plate made of a relatively soft O material or T4 material, the shape workability is excellent. In addition, when the heat treatment is performed so as to finally become a T6 material after determining the shape, it is easy to improve the shock absorption. In addition, when forming the standing piece of a flange part by a bending process, it is preferable to perform the said bending process before the said heat processing.

  In the above bumper device, the reinforcement is preferably hollow from the viewpoint of improving the impact absorption characteristics of the bumper device. In this case, one or more ribs for connecting the inner surfaces of the side wall surfaces may be provided. The cross-sectional shape when the reinforcement is cut in the vehicle longitudinal direction is preferably a substantially rectangular shape, a substantially “day” character shape, a substantially “eye” character shape, a substantially “rice” character shape, or the like. be able to. However, in this case, the side wall surface substantially parallel to the vehicle vertical direction may protrude from the side wall surface substantially parallel to the vehicle front-rear direction.

  In addition, the reinforcement is usually formed by bending both end portions on the design of the vehicle. Also in the bumper device, the reinforcement may have bent portions at both ends. In the above bumper device, the shock absorbing member can be attached to the frame of the vehicle main body on the left and right sides of the vehicle main body in the vehicle front-rear direction, etc. Two are preferably attached to the force.

  In the bumper device, it is preferable that a bottom portion of the shock absorbing member is fixed to the reinforcement by friction stir welding.

  When fixing a bottom part with a volt | bolt and a nut, pre-processing (formation of a mounting hole or nut fixation) etc. is needed with respect to a bottom part and a reinforcement, and fastening time takes. On the other hand, in the case of fixing by friction stir welding, the pre-processing is not necessary, so that the mounting time can be shortened accordingly, and mass productivity can be improved. Moreover, when fixing a bottom part by welding, there exists a possibility of an internal defect, such as a blowhole and a fusion defect, and also it is easy to generate | occur | produce distortion. On the other hand, in the case of fixing by friction stir welding, it is not necessary to worry about the occurrence of the internal defects and distortions, so that it is possible to reduce the trouble of defect inspection and improve mass productivity. In addition, when the bottom portion is fixed by the self-piercing rivet, the fixing strength is relatively low and a dedicated tool for fixing is required. On the other hand, when fixing by friction stir welding, a relatively high fixing strength can be ensured, and a dedicated tool is not required. Furthermore, in the case of fixing by friction stir welding, the weight of the bumper device can be reduced as much as fixing members such as bolts, nuts, filler metal, and self-piercing rivets are not required. Furthermore, it is possible to reduce the cost of the bumper device by improving mass productivity and reducing the number of fixing members.

  For the friction stir welding, either friction stir wire bonding or friction stir spot welding can be used. It is also possible to combine these. Further, the friction stir welding may be performed from the impact absorbing portion side or may be performed from the reinforcement side. Considering the length of the impact absorbing portion of the impact absorbing member in the vehicle front-rear direction and the like, it may be performed from the direction in which workability is easily secured.

From the viewpoint of increasing the resistance to tension by pulling or lashing, the friction stir line bonding preferably has a line bonding length of preferably 50 mm or more, a line bonding width of preferably 3 mm or more, and a line bonding area of preferably 150 mm ² or more. Good. In addition, the wire joint part of friction stir wire joining can be comprised from 1 or 2 or more in consideration of the grade etc. of the tolerance to give. On the other hand, in the friction stir spot joining, the number of striking points is preferably 6 or more striking points from the viewpoint of enhancing the resistance to pulling or pulling.

  Further, the joining direction of the friction stir welding is not particularly limited. In the shock absorbing portion of the shock absorbing member, the side wall plate disposed on the vehicle inner side in the vehicle width direction is set to have a longer length in the vehicle front-rear direction than the side wall plate disposed on the vehicle outer side in the vehicle width direction. In other words, when the bottom is inclined and provided on the vehicle outer side in the vehicle width direction, it is preferable that the friction stir welding is performed from the vehicle outer side in the vehicle width direction toward the vehicle inner side. . This is because unnecessary contact between the pins of the friction stir welding apparatus and the impact absorbing member can be easily suppressed during the friction stir welding.

  The shock absorbing member and the bumper device can be applied to either the front bumper side or the rear bumper side of the vehicle.

Example 1
The impact absorbing member and the bumper device according to the first embodiment will be described with reference to FIGS. In all the drawings, FR means the vehicle front-rear direction, FRI means the vehicle inner side in the vehicle front-rear direction, and FRO means the vehicle outer side in the vehicle front-rear direction. W represents the vehicle width direction, WI represents the vehicle inner side in the vehicle width direction, and WO represents the vehicle outer side in the vehicle width direction. Moreover, UD means the vehicle vertical direction, U means the vehicle upper side, and D means the vehicle lower side. These symbols are used as appropriate in the following description. The shock absorbing member and bumper device of this example are assumed to be applied to the front bumper side of the vehicle. However, the shock absorbing member and bumper device of this example are not limited to this, and It can also be applied to the bumper side.

<Shock absorbing member>
As shown in FIGS. 1 to 4, the impact absorbing member 1 of this example is for fixing to a bottom 11 for fixing to a reinforcement 3 for reinforcing a bumper of a vehicle and a frame (not shown) of a vehicle body. The flange portion 12 is provided between the bottom portion 11 and the flange portion 12, and has a substantially rectangular tube-shaped shock absorbing portion 13 composed of four side wall surfaces 13 a, 13 b, 13 c, and 13 d. That is, the shock absorbing member 1 of this example is formed in a bottomed substantially rectangular tube as a whole, and the outer periphery of the bottomed substantially rectangular tube on the side opposite to the bottom 11 is outside the bottomed substantially rectangular tube. The flange portion 12 protrudes from

  The bottom part 11, the flange part 12, and the impact absorbing part 13 are integrally formed by drawing a single aluminum plate material by press molding. As an aluminum plate material, a plate material of A6016 which is a 6000 series aluminum alloy was used. In press molding, first, the aluminum plate material (thickness 2.5 mm) made of the O material was press-molded to determine the shape, and then heat-treated to obtain a T6 material. In addition, the upright part 12b of the flange part 12 mentioned later was formed by bending before the said heat processing.

  In the impact absorbing member 1 of the present example, the bottom 11 is for fixing to the side wall surface 32a of the inner FRI in the vehicle longitudinal direction in the reinforcement 3. Moreover, the reinforcement 3 has the bending part 31 which bend | folds toward the inner side FRI of a vehicle front-back direction on the design of a vehicle in many cases. In this example, it is assumed that the bottom 11 is fixed to the side wall surface 32a of the inner FRI in the vehicle front-rear direction in the bent portion 31 of the reinforcement 3 as described above. Therefore, the bottom 11 is formed to be inclined in an oblique direction so as to follow the bent portion 31 of the reinforcement 3.

  The bottom part 11 is formed in a substantially square shape. Moreover, although the corner | angular part of the four corners of the bottom part 11 is formed in the shape curved so that it may become roundish, it may be formed in the shape which was square in addition to this. The outer shape of the bottom portion 11 can be determined in consideration of the outer shape on the bottom portion 11 side of the substantially square cylindrical shock absorbing portion 13.

  The bottom 11 can be fixed to the reinforcement 3 by fastening. Specifically, mounting holes (not shown) are provided at the four corners of the bottom 11 and can be fixed to the side wall surface 32a of the reinforcement 3 using bolts and nuts as fastening members. ing. In addition, the bottom 11 may be configured to be fixed to the reinforcement 3 by friction stir welding without providing the above-described mounting holes.

  In the shock absorbing member 1 of this example, the shock absorbing portion 13 is formed in a substantially rectangular tube shape, and is composed of four flat side wall surfaces 13a, 13b, 13c, and 13d. The bottom 11 is integrally connected to one end of the substantially square cylindrical shock absorber 13, and the flange 12 is integrally connected to the other end.

  Further, the side wall surfaces 13a, 13b, 13c, and 13d of the shock absorbing portion 13 are parallel surfaces formed so as to be substantially parallel to the vehicle longitudinal direction FR. That is, the side wall surfaces 13a and 13b disposed on the inner side WI and the outer side WO in the vehicle width direction are formed as flat surfaces including the vehicle longitudinal direction FR and the vehicle vertical direction UD. That is, in this example, the angle between the side wall surface 13a and the vehicle longitudinal direction FR and the angle between the side wall surface 13b and the vehicle longitudinal direction FR are both set to 0 °. Further, the side wall surfaces 13c and 13d disposed on the upper side U and the lower side D in the vehicle vertical direction are formed as flat surfaces including the vehicle longitudinal direction FR and the vehicle width direction W. That is, in this example, the angle formed by the side wall surface 13c and the vehicle longitudinal direction FR and the angle formed by the side wall surface 13d and the vehicle longitudinal direction FR are both set to 0 °.

  The substantially square cross-sectional shape immediately above the flange portion 12 in the impact absorbing portion 13 was set such that the outer dimension in the vehicle width direction W was 110 mm and the outer dimension in the vehicle vertical direction UD was 90 mm. The dimension LI of the side wall surface 13a was set to 100 mm. The dimension LO of the side wall surface 13 b is a length from the flange portion 12 to the side wall surface 32 a of the reinforcement 3. In this example, the shock absorbing portion 13 is formed in a curved shape so that the connecting portions of the side wall surfaces 13a, 13b, 13c, and 13d are rounded. You can also.

  In the impact absorbing member 1 of the present example, the flange portion 12 is for fixing to a frame of the vehicle body, specifically, to a frame of the vehicle body disposed on the outer side WO in the vehicle width direction. The flange portion 12 includes a main body portion 12a that protrudes from an edge of the shock absorbing portion 13, and a standing portion 12b that is provided on the outer periphery of the main body portion 12a and stands on the shock absorbing portion 13 side.

  The main body 12 a is formed in a substantially rectangular shape that is larger than the outer shape of the end opposite to the bottom 11 of the shock absorber 13. Specifically, the main body 12a is formed in a substantially quadrangular shape having four sides that are substantially parallel to the four sides of the intersection of the four side wall surfaces 13a, 13b, 13c, and 13d of the shock absorbing unit 13. In addition, although the corner | angular part of the four corners of the main-body part 12 is formed in the shape curved so that it may become roundish, it may be formed in the shape where it was square in addition to this.

  The flange portion 12 can be fixed to the frame of the vehicle main body by fastening at the main body portion 12a. Specifically, as shown in FIG. 2, when viewed from the central axis direction of the shock absorbing portion 13, the main body portion 12a has mounting holes 121a, 122a, 123a for fixing to the frame by fastening at substantially four corners. , 124a. That is, the mounting holes 121a, 122a, 123a, and 124a are provided at the corners of the four corners of the substantially rectangular main body 12a. Then, bolts as fastening members are inserted into the mounting holes 121a, 122a, 123a, 124a and can be fixed to the frame using nuts.

  The upright portion 12b is composed of upright pieces 121b, 122b, 123b, and 124b that are independently formed on the four sides of the main body portion 12a. That is, a space portion is formed between both end portions of the standing pieces 121b, 122b, 123b, and 124b. The standing pieces 121b, 122b, 123b, and 124b are previously formed by bending on the same surface as the main body portion 12a of the flange portion 12 by bending after press forming to be the standing pieces 121b, 122b, 123b, and 124b. Then, it formed by bending this bend margin after that. In addition, the angle | corner which the main-body part 12a and the standing part 12b (standing piece 121b, 122b, 123b, 124b) make is set to 90 degrees.

  The lengths of the upright pieces 121b, 122b, 123b, and 124b are formed longer than the distance between the centers of the mounting holes 121a, 122a, 123a, and 124a. Specifically, as shown in FIG. 2, the length T2 of the upright piece 122b in the longitudinal direction is formed longer than the center-to-center distance T1 between the mounting holes 121a and 122a. Similarly, the length in the longitudinal direction of the upright piece 123b is formed longer than the center-to-center distance between the mounting holes 122a and 123a. The length of the upright piece 124b in the longitudinal direction is longer than the center-to-center distance between the mounting holes 123a and 124a. The length of the upright piece 121b in the longitudinal direction is longer than the center-to-center distance between the mounting holes 124a and 121a.

  In this example, the outer shape of the main body 12a of the flange 12 is 200 mm in the vehicle width direction W and 180 mm in the vehicle vertical direction UD. Further, the heights of the standing pieces 121b, 122b, 123b, 124b from the main body portion 12a were all set to 15 mm. The length of the standing pieces 121b and 123b was 150 mm, and the length of the standing pieces 122b and 124b was 170 mm. The hole diameters of the mounting holes 121a, 122a, 123a, 124a were all 11 mm.

<Bumper device>
As shown in FIG. 3, the bumper device 2 of this example includes a reinforcement 3 for reinforcing a bumper of the vehicle and the impact absorbing member 1 described above. The shock absorbing member 1 has a bottom 11 fixed to the reinforcement 3 by fastening (the fastening member is omitted). As described above, in the case of adopting a configuration in which the bottom portion 11 is fixed to the reinforcement 3 by friction stir welding without providing the mounting hole, specifically, the following procedure may be used. That is, the pin of the friction stir welding apparatus is inserted into the shock absorber 13 from the opening on the flange portion 12 side of the shock absorber 13. At this time, a pin is vertically inserted at the position of the vehicle outer side WO in the vehicle width direction on the inner side surface of the bottom portion 11. Then, while rotating with the pin inserted in the bottom portion 11, the pin is moved substantially along the vehicle inner side WI in the vehicle width direction to perform the friction stir line joining. Thereafter, the movement of the pin is stopped to complete the joining, and the pin is removed from the impact absorbing portion 13. Examples of conditions at the time of friction stir wire bonding include, for example, the following conditions: pin size: shoulder diameter 16 mm, probe diameter: tip 6 mm, base 8 mm, pin rotation speed 750 rpm, pin feed rate 250 mm / min. Can do. In addition, for example, the length of the linear joint portion is 80 mm, the width is 4 mm, and the number of the linear joint portions is three in the vehicle vertical direction UD, for example.

  FIG. 3 shows the left half of the bumper device 2 when applied to the front bumper side, but on the right side of the center line S is a bumper that is symmetrical to the left half of the bumper device 2 in the vehicle front direction. There is a right half (not shown) of the device 2 in the vehicle front direction. Therefore, in this example, the two impact absorbing members 1 described above are provided.

  The reinforcement 3 extends in the vehicle width direction W, and includes a bent portion 31 that is bent at both ends toward the inner FRI in the vehicle longitudinal direction so as to have an angle of 10 ° with the vehicle width direction W. Have. The bottom 11 of the shock absorbing member 1 is fixed to the side wall surface 32a of the inner FRI in the vehicle front-rear direction at the bent portion 31 of the reinforcement 3.

  As shown in FIG. 5A, the reinforcement 3 is formed of an aluminum hollow shape whose cross-sectional shape when cut in the vehicle front-rear direction FR is a substantially “day” shape. As shown in FIG. 5 (b), the side wall surface 32b of the outer FRO in the vehicle front-rear direction and the side wall surface 32a of the inner FRI in the vehicle front-rear direction are from the upper U side and the lower D side wall surfaces 32c, 32d in the vehicle vertical direction. It may be protruding. In addition, A7N01-T6 was used as said aluminum hollow shape material.

<Evaluation of traction characteristics>
Hereinafter, in order to perform the traction characteristic evaluation, a simulation using commercially available FEM analysis software was performed on the bumper device 2 having the shape shown in FIG.

First, the bumper device 2 having the shape shown in FIG. 3 was made into a mesh model, and an analysis model for examining traction characteristics was created. Next, the following characteristics were input to this analysis model.
That is, it is assumed that the reinforcement 3 is made of a hollow shape material of an aluminum alloy (A7N01-T6) having a proof stress of 320 MPa, and the impact absorbing member 1 is made of an aluminum alloy (A6016-T6) having a proof strength of 280 MPa. The stress-strain characteristics assuming each proof stress were input to the analysis model.

  The cross-sectional shape when the reinforcement 3 was cut in the vehicle front-rear direction FR was substantially “Sun”. In a substantially “day” -shaped cross-sectional shape, the side wall surfaces 32a and 32b arranged in the vehicle longitudinal direction FR have dimensions of 100 mm, the thickness is 4 mm, and the side wall surfaces 32c and 3d arranged in the vehicle vertical direction UD have a size of 80 mm. The thickness of the central rib 33 was 2 mm. In addition, the reinforcement 3 was in a state where both ends were bent so as to have an angle of 10 ° with the vehicle width direction.

  Further, the substantially square cross-sectional shape immediately above the flange portion 12 in the shock absorbing portion 13 has an outer dimension in the vehicle width direction W of 110 mm and an outer dimension in the vehicle vertical direction UD of 90 mm. Further, the dimension LI of the side wall surface 13a disposed on the inner side WI in the vehicle width direction is set to 100 mm. The dimension LO of the side wall surface 13b disposed on the outer side WO in the vehicle width direction is a length from the main body portion 12a of the flange portion 12 to the side wall surface 32a of the reinforcement 3.

  Further, the outer shape of the main body portion 12a of the flange portion 12 is 200 mm in the vehicle width direction W and 180 mm in the vehicle vertical direction UD. In addition, the heights of the standing pieces 121b, 122b, 123b, and 124b were all 15 mm. The length of the standing pieces 121b and 123b was 150 mm, and the length of the standing pieces 122b and 124b was 170 mm. The hole diameters of the mounting holes 121a, 122a, 123a, 124a were all 11 mm.

  Next, as shown in FIG. 6, a simulation for examining the traction characteristics was performed on the analysis model to which the above characteristics were input. Specifically, it is assumed that the traction hook 4 is attached to the side wall surface 32b of the outer side FRO in the vehicle front-rear direction at the bending portion 31 of the reinforcement 3, and the forced displacement is performed at a speed setting of 100 mm / s with respect to this portion. (Displacement in the direction of the arrow F in FIG. 6 and the outer FRO direction in the vehicle longitudinal direction). In FIG. 6, 5 is a rigid body that simulates a vehicle body frame. The main body 12a of the flange 12 is fastened to the rigid body 5 by bolts and nuts (not shown).

  Usually, the bumper device is loaded with a traction load on an outer side FRO in the vehicle front-rear direction via a traction hook. At that time, it can be said that the smaller the displacement of the load point, the better the traction characteristics. Specifically, in the bumper device, a traction load is applied to the outer side FRO in the vehicle front-rear direction on the impact absorbing member through the reinforcement. As a result, deformation is likely to occur such that the flange portion of the shock absorbing member is lifted from the frame of the vehicle body. The traction characteristics are excellent so that this type of deformation does not occur in the flange portion.

  It should be noted that an impact absorbing member similar to that shown in FIG. 1 (the impact absorbing member according to Comparative Example 1) except that the standing portion 12b (standing pieces 121b, 122b, 123b, and 124b) is not formed on the outer periphery of the main body portion 12a of the flange portion 12. The same simulation as described above was performed for the bumper device using the above (a bumper device according to Comparative Example 1).

  The simulation result is shown in FIG. FIG. 7 shows the relationship between the load point displacement and the load. From this figure, the amount of displacement when plastic deformation starts can be obtained. FIG. 7 shows not only the result of Example 1 but also the result of Example 2 described later. As shown in FIG. 7, when the same load is applied, the bumper device of Example 1 has a smaller displacement than the bumper device of Comparative Example 1. It can also be seen that the load Q at which plastic deformation starts is higher in the bumper device of Example 1 than in the bumper device of Comparative Example 1. From this result, it was confirmed that the impact absorbing member and bumper device of Example 1 had excellent traction characteristics.

From the above, it can be said that the impact absorbing member 1 of this example is excellent in mass productivity and traction characteristics when attached to the reinforcement 3.
Specifically, the bottom part 11, the flange part 12, and the impact absorbing part 13 are integrally formed by press-molding a single aluminum plate material. Therefore, the number of parts is reduced as compared with the case where an extruded profile is used, and manufacturing processes such as cutting of each part and assembly by wire welding of parts are not required. Further, the upright portion 12b is composed of upright pieces 121b, 122b, 123b, and 124b that are formed independently of each other on the four sides of the substantially rectangular main body portion 12a. Therefore, it can be easily formed by a simple bending process. Therefore, it is very excellent in mass productivity.

  Moreover, the flange part 12 has the main-body part 12a which protrudes from the edge of the shock-absorbing part 13, and the standing part 12b which is provided in the outer periphery of the main-body part 12a and stands on the shock-absorbing part 12a side. Therefore, the rigidity of the flange portion 12 can be improved, and the deformation resistance against the traction load is improved. In particular, the length of the upright pieces 121b, 122b, 123b, 124b is set longer than the center-to-center distance between the mounting holes 121a, 122a, 123a, 124a in the vicinity of both ends of the upright pieces 121b, 122b, 123b, 124b. . Therefore, it is excellent in the balance between the bending formability of the standing pieces 121b, 122b, 123b, and 124b and the rigidity improvement effect of the flange portion 12.

  Therefore, the bottom portion 11 is fixed to the reinforcement 3 and the flange portion 12 is fixed to the frame of the vehicle body, and applied to the vehicle front direction (when applied to the front bumper side) or the vehicle rear direction (rear bumper side). Even when a traction load is applied to the case, it can be said that the permanent deformation is difficult and excellent traction characteristics can be exhibited.

  Moreover, since the bumper apparatus 2 of this example uses the impact absorbing member 1 of this example, it can be said that it is excellent in mass productivity and traction characteristics when towing the vehicle.

(Example 2)
The shock absorbing member and bumper device according to the second embodiment will be described with reference to FIGS. Compared with the shock absorbing member 1 and the bumper device 2 according to the first embodiment, the shock absorbing member 1 and the bumper device 2 according to the second embodiment have four side wall surfaces 13a, 13b, 13c, which constitute the shock absorbing portion 13. 13d and the main body part 12a of the flange part 12 are different in that a plurality of bead parts 15 are provided. Other configurations are the same as those of the shock absorbing member 1 and the bumper device 2 according to the first embodiment.

  In the shock absorbing member 1 of the second embodiment, the bead portion 15 is connected to the side wall surfaces 13c and 13d and two to the intersections between the side wall surfaces 13a and 13b and the flange portion 12a connected to them. Three each are formed at the intersection with the flange portion 12a. In addition, the pitch of each bead part 15 in the intersection part of side wall surface 13a, 13b and the flange part 12a connected to them was 30 mm. Moreover, the pitch of each bead part 15 in the intersection part of the side wall surfaces 13c and 13d and the flange part 12a connected to them was 27.5 mm.

  As shown in FIG. 10, the bead part 15 is comprised from the bulging part bulged by carrying out plastic deformation toward the valley side 15T from the mountain | side 15Y of a crossing part. In this example, the bead portion 15 was formed by molding. Moreover, as shown in FIG. 11, the cut surface when cut along a plane that includes the intersection of the side wall surface 13c and the main body portion 12a and that forms an angle with the main body portion 12a is substantially triangular. It is formed (the same applies to the remaining side wall surfaces 13a, 13b, 13d). The angle (vertical angle θ) formed by the surface 151 and the surface 152 constituting the bead portion 15 was 90 °. Further, the distance h from the intersection to the apex X of the substantially triangle was about 7 mm.

  For the impact absorbing member 1 and the bumper device 2 of Example 2 configured as described above, in order to confirm the effect of forming the bead portion, a simulation similar to that of Example 1 was performed and traction characteristics were evaluated.

  The simulation result is shown in FIG. As shown in FIG. 7, when the same load is applied, the bumper device 2 of the second embodiment has a smaller amount of displacement than the bumper device 2 of the first embodiment. It can also be seen that the load Q at which plastic deformation starts is higher in the bumper device 2 of the second embodiment than in the bumper device 2 of the first embodiment. From this result, it can be seen that by forming the bead portion 15 at the intersecting portion, the rigidity of the intersecting portion can be improved, and the deformation resistance against the traction load is further improved. As described above, it was confirmed that the impact absorbing member 1 and the bumper device 2 of Example 2 had even better traction characteristics. Moreover, since the bead part 15 is comparatively easy to introduce into the intersection part, it can be said that it is difficult to impair the mass productivity.

  Although the embodiments have been described above, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 1 Shock absorption member 11 Bottom part 12 Flange part 12a Body part 121a-124a Mounting hole 12b Standing part 121b-124b Standing piece 13 Shock absorption part 13a Side wall surface (vehicle inside)
13b Side wall surface (vehicle outside)
13c Side wall surface (vehicle upper side)
13d Side wall (vehicle lower side)
15 Bead part 2 Bumper device 3 Reinforcement 31 Bending part 32a Side wall surface (vehicle inside)
32b Side wall surface (vehicle outside)
32c Side wall (upper side of vehicle)
32d Side wall surface (vehicle lower side)
33 Central rib

Claims (7)

A bottom for fixing to a reinforcement for reinforcing a vehicle bumper;
A flange for fixing to the frame of the vehicle body;
A shock absorber having a substantially rectangular tube shape, which is provided between the bottom and the flange, and includes four side wall surfaces;
The bottom part, the flange part, and the shock absorbing part are integrally formed by press-molding a single aluminum plate,
The said flange part has a main-body part which protrudes from the edge of the said shock-absorbing part, and the standing part which is provided in the outer periphery of this main-body part and stands on the said shock-absorbing part side, The shock-absorbing member characterized by the above-mentioned. The impact-absorbing member according to claim 1,
The main body is formed in a substantially rectangular shape having four sides substantially parallel to the four sides of the intersection with the four side wall surfaces of the shock absorbing portion,
The shock-absorbing member, wherein the upright portion is composed of upright pieces formed independently on each of the four sides of the main body portion. The impact absorbing member according to claim 2,
The main body has mounting holes for fixing to the frame by fastening at substantially four corners, and the length of each upright piece is longer than the center-to-center distance between the mounting holes. Shock absorbing member. In the impact-absorbing member according to any one of claims 1 to 3,
1 or 2 or more bead parts are formed in the crossing part of any one or more side wall surfaces among the four side wall surfaces which comprise the said shock absorption part, and the main-body part of the said flange part. A shock absorbing member characterized by the above. In the impact-absorbing member according to any one of claims 1 to 4,
The said aluminum plate material consists of a 6000 series aluminum alloy, The impact-absorbing member characterized by the above-mentioned. Reinforcement for vehicle bumper reinforcement,
The shock absorbing member according to any one of claims 1 to 5,
The bumper device, wherein the impact absorbing member has the bottom portion fixed to the reinforcement. The bumper device according to claim 6, wherein
The bumper device, wherein the bottom of the shock absorbing member is fixed to the reinforcement by friction stir welding.

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