JP4789471B2 - Bumper reinforcement and bumper structure - Google Patents

Description

  The present invention relates to a structure of a bumper reinforcement made of extruded aluminum alloy that is attached to the front and rear of an automobile.

In recent years, aluminum alloys have been used for various members for automobiles in response to demands for weight reduction of automobiles, and aluminum alloy extruded materials having a hollow cross section are also used for bumper reinforcements.
As shown in FIG. 4, the bumper reinforcement 1 made of an aluminum alloy extruded material is generally bent at the end regions 2 and 2 on both sides in the vehicle width direction toward the vehicle body in a horizontal plane, and the rear wall 1b is a bumper stay 3. It is fixed and supported. The bumper reinforcement 1 and the bumper stay 3 are fixed by appropriate means such as bolt or rivet fastening or welding.
A bumper cover 4 is disposed in front of the bumper reinforcement 1 so as to surround the bumper reinforcement 1, and a filler (not shown) such as urethane is filled between the bumper cover 4 and the bumper reinforcement 1. The aluminum alloy extruded material 1A used for forming the bumper reinforcement 1 is appropriately selected to have a cross-sectional shape such as a mouth shape, a date shape, and an eye shape for the purpose of satisfying the collision performance. In FIG. 4, the example using the extrusion material of the daily cross-sectional shape which consists of the front wall 1a, the rear wall 1b, and the horizontal walls 1c, 1d, and 1e is shown.

The joint between the bumper stay 3 and the bumper reinforcement 1 is bolt joint in consideration of exchangeability, and the joint position is generally a stay main body (shaft portion) 3a as shown in FIG. At the outside position (the bolt joint position is indicated by an arrow X). If the stay width is sufficiently wide, it is also possible to provide a bolt joint position (indicated by an arrow X) inside the stay main body 3a as shown in FIG. However, in the latter case, since the bolt exists immediately above the bumper stay 3, the stroke that can be crushed by the bumper reinforcement 1 is shortened immediately above the bumper stay 3 (the remaining width t of the collapse is increased), and energy is absorbed. There is a disadvantage that the amount is reduced.
In addition, since the safety standards for collisions in recent years have become stricter, the bumper stay 3 is also required to have a certain load capacity and energy absorption amount. In order to achieve this, it has become effective to use an aluminum alloy bumper stay whose extrusion direction is the longitudinal direction of the vehicle body. This structure has a closed cross-section structure with a vertical wall parallel to the collision direction, so that both increased deformation load and light weight can be achieved. Generally, welding is performed on the front side and rear side of the bumper stay. A flange is attached by, for example, and is attached to a bumper reinforcement and a vehicle body (side member) through this.

The bent shape of the bumper reinforcement 1 is determined on the basis of design requirements because it needs to have a certain impact resistance not only from the front of the automobile but also from the oblique direction. From the viewpoint of the latter, the shape of the bumper reinforcement 1 is determined so that a predetermined space is formed between both ends of the bumper reinforcement 1 and the bumper cover 4 in the bumper cover 4 that is a part of the external design of the automobile. It is done.
On the other hand, the bumper reinforcement 1 must be fixed to the tip of the bumper stay 3. The bumper stay 3 is disposed on an extension of a side member (not shown), and the position of the side member in the vehicle width direction is determined by the structure of the vehicle body frame. Therefore, the shape of the bumper reinforcement 1 is also restricted by the position of the bumper stay 3 in the vehicle width direction.

  For example, as shown in the following Patent Documents 1 to 5, bumper reinforcements having various shapes have been proposed within the range of the above-described restrictions, particularly with respect to the end regions on both sides.

Japanese Patent Laid-Open No. 7-25296 JP-A-7-186849 JP 2000-335333 A JP 2003-146156 A JP 2004-189171 A

In the bumper structure shown in FIG. 4 , since the bumper stay 3 is located considerably outside in the vehicle width direction (the distance between the left and right side members is wide), the bumper stay 3 has end regions 2 on both sides of the bumper reinforcement 1. , 2. Considering the case where the shape of the bumper cover 4 is the same and the bumper stay 3 is disposed further outward in the vehicle width direction (the distance between the left and right side members is wider), the following problem may occur.
(1) As shown in FIG. 6A, when the same space (indicated by the width S) as the bumper structure of FIG. 4 is formed between the end of the bumper reinforcement 1 and the bumper cover 4, the bumper reinforcement 1 The mounting surface necessary for mounting the bumper stay 3 cannot be secured on the rear wall of the rear surface (the width of the mounting surface is insufficient). In other words, the width of the bumper reinforcement 1 is insufficient.
When the width of the bumper stay 3 is sufficiently large, as shown in FIG. 6B, it is possible to bolt the bumper reinforcement 1 directly on the bumper stay 3 as shown in FIG. As described with reference to), the bumper reinforcement 1 can be crushed in a portion immediately above the bumper stay 3, so that the amount of energy absorption is reduced.
(2) On the other hand, as shown in FIG. 6C, if the mounting surface necessary for mounting the bumper stay 3 is secured on the rear wall of the bumper reinforcement 1, the width of the bumper reinforcement 11 in the vehicle width direction can only be increased. In addition, a space (indicated by the width Sa) formed between the end of the bumper reinforcement 1 and the bumper cover 4 becomes narrow, and an appropriate space cannot be obtained.

  In the case of using a bumper reinforcement made of an aluminum alloy extruded material, the present invention can secure a mounting surface necessary for mounting a bumper stay on the rear wall of the bumper reinforcement, and the end of the bumper reinforcement and the bumper cover. It is an object to make it possible to configure an appropriate space between.

As shown in FIG. 4, the bumper reinforcement made of an aluminum alloy extruded material is generally manufactured by cutting the aluminum alloy extruded material 1A along a plane perpendicular to the extrusion direction and bending both ends. Accordingly, in the bumper reinforcement, the front wall side of the end region (both end portions bent) on both sides in the vehicle width direction protrudes left and right, and the rear wall side recedes inward in the vehicle width direction from the above . This invention pays attention to this point, and achieves the said objective by changing the cutting | disconnection form of an aluminum alloy extruded material.
That is, the present invention is made of an aluminum alloy extruded material having a hollow cross section provided with a front wall, a rear wall, and a lateral wall connecting them, and end regions on both sides in the vehicle width direction are bent toward the vehicle body in a horizontal plane, In the bumper reinforcement where the bumper stay is attached to the rear wall of the part area, both ends are cut along a vertical plane inclined from the plane perpendicular to the extrusion direction, and the rear wall side of both ends extends in the extrusion direction from the front wall side. The extended portion of the rear wall is a part of the mounting surface of the bumper stay.

In the present invention, the material of the aluminum alloy extruded material is not particularly limited, but is preferably JIS6000 or 7000 based on the relationship satisfying extrudability and product strength, and the cross-sectional shape is rectangular such as mouth side, date shape, eye shape, etc. Or a front wall and / or rear wall of a similar cross-sectional shape that protrudes up and down in a flange shape from the lateral wall (ladder-shaped cross section).
Further, in the bumper reinforcement, the end regions on both sides are generally curved outside the corner portion even if only the bent corner portion is curved and the outside is linearly inclined. May be. Further, the present invention also includes a bumper reinforcement that is entirely curved including the end region (all-R bending bumper).
Further, in the present invention, the bumper stay is made of an aluminum alloy extruded material having a closed cross-sectional structure in which the shaft portion extends in the longitudinal direction of the vehicle body, and on the outside of the shaft portion at the front and rear ends (bumper reinforcement side and side member side). It is desirable to have a mounting flange, and the mounting flange is attached to the mounting surface.

According to the present invention, when using bumper reinforcement made of an aluminum alloy extruded material, the distance between the left and right bumper stays is wide, and even when each bumper stay is disposed at the end of the bumper reinforcement, the rear wall of the bumper reinforcement is provided. A mounting surface necessary for mounting the bumper stay can be secured, and an appropriate space can be formed between the end of the bumper reinforcement and the bumper cover.
Further, according to the present invention, the amount of energy absorption and deformation load at the time of offset collision and the like increase compared to the bumper reinforcement of the conventional shape, and conversely, the amount of energy absorption and deformation load is the same level as that of the bumper reinforcement of the conventional shape. Therefore, the thickness of the aluminum alloy extruded material can be designed to be thin in advance, and a lighter bumper reinforcement can be provided.

Hereinafter, the bumper reinforcement according to the present invention will be described in detail with reference to FIGS.
The bumper reinforcement 11 is made of an aluminum alloy extruded material having a cross-sectional shape of a daily shape (see FIG. 4C), and as shown in FIG. , 12 are bent at a predetermined angle toward the vehicle body in a horizontal plane. As shown in FIG. 1 (b), the aluminum alloy extruded material 11A as a material is cut obliquely at both ends from the front wall 11a side to the rear wall 11b side (the cut surface is perpendicular to the upper and lower walls and in the extrusion direction). As a result, at both ends of the aluminum alloy extruded material 11A, compared with the aluminum alloy extruded material 1A (FIG. 1 (d)) used in the conventional bumper reinforcement, FIG. ), A triangular portion (additional portion 11Aa) in a plan view with hatched phantom lines is added, and the rear wall 11b side extends in the extrusion direction from the front wall 11a side (rear wall 11b). Extension portion 11ba, extension width W). The extended width W of the rear wall 11b is determined by an inclination angle (cutting angle) between the cut surface and a surface perpendicular to the extrusion direction.
The bumper reinforcement 11 is obtained by bending the aluminum alloy extruded material 11A.

In the aluminum alloy extruded material 11A, the rear wall 11b side extends in the extrusion direction (length direction) by the extension width W from the front wall 11a side. On the other hand, in the bumper reinforcement 11 after bending, when viewed in the extrusion direction, the rear wall 11b side is similarly extended from the front wall 11a side by the extension width W, but the end regions 12 and 12 are inclined. When viewed in the vehicle width direction, the width of the bumper reinforcement 11 is hardly increased as compared with the conventional example without the extension portion 11ba. It is also possible to not increase the width in the vehicle width direction of the bumper reinforcement 11 at all by adjusting the width (= cutting angle) of the extension portion 11ba.
Therefore, the bumper reinforcement 11 can form an appropriate space between the end of the bumper reinforcement 11 and the bumper cover 4 even though the rear wall 11b side extends.
And since this bumper reinforcement 11 has the extension part 11ba in the rear surface wall 11b side, although the space | interval of bumper stays 3 and 3 is wide and each is arrange | positioned at the edge part of the bumper reinforcement 11, this extension part Since the flange of the bumper stay 3 can be brought into contact with 11ba as a part of the mounting surface, a sufficient mounting surface for mounting the bumper stay 3 can be secured.

Moreover, since this bumper reinforcement 11 has additional part 11Aa, there exists an advantage which the energy absorption amount and deformation | transformation load at the time of an offset collision etc. increase. As for the bumper reinforcement 11 with the additional portion 11Aa and the bumper reinforcement 1 without the additional portion 11Aa, the crushing area at the time of the offset collision is naturally the same at the inner portion of the vehicle body from the bumper stay 3, while the bumper reinforcement 1 In the vehicle body outer side portion than the stay 3, the former is larger than the latter by the additional portion 11Aa. FIG. 2 schematically shows this, and it can be seen that there is a difference in the width (T> T ₀ ) of the crushing portion at the outer portion of the vehicle body from the bumper stay 3, and the crushing area is increased in the bumper reinforcement 11. And the energy absorption amount and deformation | transformation load of the bumper reinforcement 11 increase by the increase in this crushing area.
If the energy absorption amount and deformation load are kept at the same level as that of the bumper reinforcement 1 having the conventional shape, the side wall of the bumper reinforcement 11 that causes crushing deformation at the time of collision (see 11c to 11e in FIG. 4C) is designed to be thin. can do. Since this lateral wall extends in the vehicle body width direction, the lightening effect due to this thinning is larger than the weight increase due to the increase in the end region (additional portion 11Aa) of the bumper reinforcement 11 due to the cutting angle change. A lightweight bumper reinforcement structure can be provided.

  Furthermore, as shown in FIG. 3, if the cross-sectional shape of the aluminum alloy extruded material 11A is plane-symmetric in the longitudinal direction of the vehicle body (the symmetry plane PS is indicated by a one-dot chain line), the cutting directions (the cutting plane is indicated by Y) are alternately changed Thus, the yield reduction can be minimized as compared with the conventional bumper reinforcement that cuts perpendicularly to the extrusion direction.

The partial cross section top view (a) of the bumper structure (a bumper cover is included) concerning the present invention, the top view (b) of the aluminum alloy extrusion before bending, the partial enlarged view (c), and before bending It is a top view (d) of an aluminum alloy extrusion material (conventional material). It is explanatory drawing (this invention (a) and a prior art example (b)) of the crushing deformation | transformation part of bumper reinforcement at the time of an offset collision. It is a figure explaining the method to cut out the material for bumper reinforcement from a long aluminum alloy extrusion material. It is a partial cross section top view (a) of the conventional bumper structure (a bumper cover is included), the top view (b) of the aluminum alloy extrusion material before a bending process, and its side view (c). It is a schematic diagram explaining two joining systems of bumper reinforcement and a stay, and each crushing form. It is a partial cross section top view of a bumper structure (a bumper cover is included) for demonstrating the problem of a prior art.

Explanation of symbols

1,11 Bumper reinforcement 11Aa additional part
DESCRIPTION OF SYMBOLS 1a, 11a Front wall 1b, 11b Rear wall 11ba Rear wall extension 1c-1e Upper and lower walls 2,12 End region of bumper reinforcement 3 Bumper stay 4 Bumper cover

Claims (2)

It consists of an aluminum alloy extruded material (11A) with a hollow cross section provided with a front wall (11a) , a rear wall (11b) and a lateral wall connecting them, and the end regions (12, 12) on both sides in the vehicle width direction are within the horizontal plane In the bumper reinforcement (11), which is bent toward the vehicle body and attached to the rear wall (11b) of the end region (12, 12) by contacting the flange at the front end of the bumper stay (3), the extruded aluminum alloy ( 11A) is cut along a vertical plane whose both ends are inclined from a plane perpendicular to the extrusion direction, and the rear wall side of both ends is extended by an extension width (W) determined by the inclination angle between the cut plane and the plane perpendicular to the extrusion direction. has been extended from the front wall side in the extrusion direction, extension of the rear wall (11b) (11ba) is part of the mounting surface on which the flange of the bumper stay (3) abuts Bumper reinforce characterized the door (11). A bumper structure comprising the bumper reinforcement (11) according to claim 1 and a bumper stay (3) attached to the mounting surface of the bumper reinforcement (11) .

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