JP5063459B2 - Automotive bumper structure - Google Patents

Description

  The present invention relates to an automobile bumper structure having a main beam (bumper reinforcement) and an auxiliary beam for protecting pedestrians (auxiliary bumper reinforcement).

For example, as described in Patent Document 1, it is known to install an auxiliary beam via a support arm below a main beam for pedestrian protection. In the case of a normal bumper with only the main beam installed, when it collides with a pedestrian facing in the direction of the car, the main beam hits the pedestrian's knee joint from the front and causes great damage such as bending the knee joint in reverse. In the case of a bumper where an auxiliary beam is installed below the main beam and the collision surface is positioned in front of the main beam, the auxiliary beam hits the pedestrian shin near the main beam and pushes the knee joint. Since the main beam strikes the knee joint after bending in the normal direction (inward), there is an advantage that damage to the knee joint can be reduced.
In addition, the auxiliary beam has a function of preventing the colliding pedestrian from getting under the vehicle body. In this case, it is not essential that the collision surface of the auxiliary beam be positioned in front of the main beam.
In the present specification, regardless of the front side and the rear side of the automobile, the collision surface side is the front and the vehicle body side is the rear.

Japanese Patent Laying-Open No. 2005-306161

In order to install the auxiliary beam, it is necessary to fix a pair of left and right support arms to the main beam and fix the auxiliary beam to the support arm. In Patent Document 1, it is considered that a welded joint is probably used as a fixing means because sheet metal molded products are used as the main beam and the auxiliary beam, and a round pipe having a circular cross section is used as the support arm. There is a problem like this.
(1) Since the main beam and the support arm and the support arm and the auxiliary beam are in line contact, the contact area is small, and the impact load on the auxiliary beam is locally transmitted to the main beam, so that stable load displacement cannot be obtained. There is a risk of unexpected load displacement.
(2) The joining of the main beam and the support arm is also a welding joint, which may be a cause of failure to obtain a stable load displacement at the time of collision. That is, the reliability of welding is low (it is difficult to predict the fracture of the welded portion), and at the time of a collision, the welded portion may break and a sudden drop in load may occur. Conversely, the degree of coupling between the main beam and the support arm is too high, and a sudden increase in load may occur, resulting in a large impact on the pedestrian.
(3) Since the support arm is made of a pipe having a circular cross section, the positioning with respect to the main beam and the auxiliary beam is difficult.
(4) It is necessary to bend the round pipe for manufacturing the support arm, which increases the number of processes.
(5) In the case of a welded structure, plastic distortion occurs due to the heat input of welding, and in particular, if distortion occurs at the joint between the main beam and the support arm, the product accuracy during assembly decreases.

  The present invention has been made in view of the above-described problems of the prior art. In an automobile bumper structure in which an auxiliary beam is disposed below a main beam via a support arm, the main beam, the support arm, and Increase the contact area between the support arm and the auxiliary beam as needed, avoid joining the main beam and the support arm by welding so that stable load displacement can be obtained at the time of collision with the auxiliary beam, and at the same time increase the number of extra steps An object is to provide a bumper structure that can be reduced.

  The present invention relates to a bumper structure for an automobile comprising a main beam, left and right support arms whose upper ends are fixed to the main beam, and an auxiliary beam fixed to the lower end of the support arm and positioned below the main beam. In the body, the main beam, the auxiliary beam and the support arm are all made of an aluminum alloy extruded shape, and the support arm is hollow in cross section and the extrusion direction is parallel to the longitudinal direction of the main beam and the auxiliary beam A first mounting wall disposed at the upper end of the outline of the hollow cross section abuts the lower surface of the main beam, and a bracket longer than the width of the support arm in the push-out direction passes through the hollow cross-section and extends in the push-out direction of the support arm. The central part of the first mounting wall contacts the lower surface of the first mounting wall, and the left and right sides contact the lower surface of the main beam and contact the main beam by a fastening element. Is characterized in that the second mounting wall positioned near the lower end of the contour of the hollow section is joined to the auxiliary beam in contact with the installation surface of the auxiliary beam. The fastening element refers to a mechanical fastening means such as a bolt / nut or a rivet.

In the above invention, the following embodiments can be adopted as appropriate.
(1) The collision surface of the auxiliary beam is positioned in front of the collision surface of the main beam.
(2) The support arm has a third mounting wall protruding above the outline of the hollow cross section, and the third mounting wall is in contact with the back surface of the main beam and joined to the main beam by a fastening element. Being.
(3) The support arm has a front wall, a rear wall, and a plurality of rib walls connecting the both walls, and the rib wall at the upper end serves as the first mounting wall.
(4) The support arm has a front wall, a rear wall, and a plurality of rib walls connecting the two walls, the rib wall at the upper end serves as the first mounting wall, and a part of the rear wall is the hollow section. Projecting above the outline of the first mounting wall.
(5) The outline of the hollow cross section of the support arm is substantially L-shaped, the rib wall formed at the upper end of the L-shaped outline is the first mounting wall, and the substantially L-shaped outline The rib wall formed at the front end is the second mounting wall, and the second mounting wall is in contact with the back surface of the auxiliary beam and joined to the auxiliary beam.

In the present invention, the main beam, auxiliary beam, and support arm are all made of an aluminum alloy extruded shape, and the extrusion direction of the support arm is parallel to the longitudinal direction of the main beam and auxiliary beam (that is, the extrusion of three members). So that the contact area between the main beam and the support arm and between the support arm and the auxiliary beam can be easily increased as necessary, and avoiding joining of the main beam and the support arm by welding. The support arm is fixed to the main beam by the bracket, and the bracket is joined to the main beam by the fastening element. The degree of coupling is low compared to welding, and the support arm is allowed to rotate relative to the main beam depending on the size of the load. Therefore, a stable load displacement can be obtained at the time of collision with the auxiliary beam, and an unexpected load displacement can be prevented. At the same time, the contact between the main beam and the support arm and the support arm and the auxiliary beam is all surface contact, so that the degree of freedom of positioning of the support arm with respect to the main beam and the auxiliary beam is reduced compared to the round pipe, and mutual positioning is easy It becomes.
Further, since the support arm can be obtained simply by cutting the extruded profile, the number of extra steps can be reduced as compared with the case of using a round pipe.

Hereinafter, the bumper structure according to the present invention will be described with reference to FIGS.
The bumper structure shown in FIGS. 1 to 3 includes a main beam 1, a pair of left and right support arms 2, and an auxiliary beam 3. The support arm 2 has an upper end fixed to the main beam 1, and the auxiliary beam 3 is supported by the support beam 3. It is fixed to the lower end of the arm, and the collision surface 3A is located below the main beam 1 and ahead of the main beam collision surface 1A.
The main beam 1 is made of an aluminum alloy extruded section having a so-called daily cross section, and includes a front wall 4 and a rear wall 5 that are substantially perpendicular to the load direction at the time of collision, and a lateral wall 6 that connects the front wall 4 and the rear wall 5 substantially perpendicularly. And the front surface of the front wall 4 is the collision surface 1A.

The auxiliary beam 3 is made of an aluminum alloy extruded section having a so-called mouth-shaped cross section, and has a front wall 9 and a rear wall 11 that are substantially perpendicular to the load direction at the time of collision, and a lateral wall 12 that connects the front wall 9 and the rear wall 11 substantially perpendicularly. , 13 and the front surface of the front wall 9 is the collision surface 3A. The auxiliary beam 3 is bent at both ends in the same manner as the main beam 1 and is inclined to the vehicle body side (rear side). The main beam 1 and the central portions 1a and 3a of the auxiliary beam 3 and the inclined portions 1b and 3b are mutually connected. It is almost parallel.
The support arm 2 is obtained by cutting an aluminum alloy extruded material having a hollow cross section perpendicularly to the extrusion direction. Rib walls 16-21 are provided. Lower portions of the front wall 14 and the rear wall 15 are bent forward, and rib walls 16 and 21 at both ends are formed substantially perpendicular to the front wall 14 and the rear wall 15, and the front wall 14, the rear wall 15, and the ribs are formed. The walls 16 and 21 form a hollow cross-sectional outline, which is substantially L-shaped. The rear wall 15 has a protruding wall 15a protruding upward from the outline of the hollow cross section.

The support arm 2 is installed on the inclined portion 1b of the main beam 1 and is arranged so that its pushing direction is substantially parallel to the longitudinal direction (extrusion direction) of the main beam 1. The extrusion direction is naturally substantially parallel to the longitudinal direction (extrusion direction) of the auxiliary beam 3.
The rib wall 16 (hereinafter referred to as the first mounting wall 16) at the upper end of the support arm 2 is in contact with the lower surface of the main beam 1, that is, the lower surface of the lateral wall 8, and the protruding wall 15a (hereinafter referred to as the third mounting wall 15a). The rib wall 21 at the front end (hereinafter referred to as the second mounting wall 21) is in contact with the back surface of the main beam 1, that is, the back surface of the rear wall 5. It is in contact.

A bracket 22 longer than the width of the support arm 2 (the width in the extrusion direction) is disposed along the extrusion direction of the support arm 2 through the hollow cross section, and as shown in FIG. The left and right sides abut against the lower surface of the mounting wall 16, that is, the lower surface of the main wall 1, that is, the lower surface of the lateral wall 8, and the main beam 1 (more specifically, to the lateral wall 8) Fastened and joined. As a result, the support arm 2 is fixed to the main beam 1 with the first mounting wall 16 being pressed against the lower surface of the main beam 1. As the bracket 22, a press-molded plate or an extruded shape can be used.
The third mounting wall 15a abuts against the back surface of the main beam 1 and is joined to the main beam 1 (more specifically, to the rear wall 11) by bolts and nuts 24. By supplementarily joining the third mounting wall 15a to the main beam 1, the mounting strength of the support arm 2 to the main beam 1 is increased.
The second mounting wall 21 abuts on the back surface of the auxiliary beam 3 and is joined to the auxiliary beam 3 (more specifically, to the rear wall 11) by bolts and nuts 25.

FIG. 4 shows another example of the fastening structure of the main beam 1 and the support arm 2.
In the fastening structure shown in FIG. 4, a hole is made in the lateral wall 8 of the main beam 1 and a blind nut 26 is attached, and the bracket 22 is attached to the main beam 1 (more specifically, to the lateral wall 8) by the blind nut 26 and the bolt 27. It is concluded. The bracket 22 is made of an aluminum alloy extruded shape, and a groove 22a for accommodating the flange 26a of the blind nut 26 is formed on the upper left and right sides (only the right side is shown in FIG. 4). The blind nut 26 is suitable when a nut and a fastening tool cannot be inserted into the hollow cross section of the main beam 1.

With reference to FIG. 5, another bumper structure according to the present invention will be described. In FIG. 5, the same reference numerals are given to substantially the same parts as the bumper structure shown in FIG.
The bumper structure shown in FIG. 5 differs from the bumper structure shown in FIG. 1 only in the cross-sectional structure of the support arm 2. This support arm 2 is also obtained by cutting an aluminum alloy extruded material having a hollow cross section perpendicularly to the extrusion direction, and has a front wall 14, a rear wall 15, and a plurality of rib walls 16 to 21 connecting both walls 14, 15. . The front wall 14 and the rear wall 15 are inclined obliquely forward at substantially equal intervals over the entire length, the rib walls 16 and 21 at both ends are substantially horizontal, and are hollow by the front wall 14, the rear wall 15 and the rib walls 16 and 21. A cross-sectional outline is formed, which is substantially I-shaped. The lower end portion 14a of the front wall 14 is slightly bent to be substantially vertical (substantially parallel to the rear wall 11 of the auxiliary beam 3), and the rear wall 15 has a protruding wall 15a that protrudes upward from the outline of the hollow cross section.

The rib wall 16 (first mounting wall 16) at the upper end of the support arm 2 is in contact with the lower surface of the main beam 1, that is, the lower surface of the lateral wall 8, and the protruding wall 15a (third mounting wall 15a) is the back surface of the main beam 1. In other words, the rear wall 5 is in contact with the back surface, and the lower end 14a of the front wall 14 (hereinafter referred to as the second mounting wall 14a) is in contact with the back surface (attached surface) of the auxiliary beam 3, that is, the back surface of the rear wall 11.
According to this bumper structure, when the automobile collides with a pedestrian, the auxiliary beam 3 hits the pedestal of the pedestrian before the main beam 1 and bends the knee joint in the normal direction, and then the main beam strikes the knee joint. Therefore, damage to the knee joint can be reduced. At this time, the load applied to the auxiliary beam 3 is transmitted to the main beam 1 as a bending moment and is received by the main beam 1.
In the support arm 2, the first mounting wall 16 is mechanically fixed to the lower surface of the main beam 1 with bolts and nuts. Therefore, unlike the conventional welding joint, the load displacement applied to the auxiliary beam 2 at the time of collision is stable and Predictable.

This bumper structure has a high specific rigidity due to the hollow cross-sectional structure in which the front wall 14 and the rear wall 15 are connected by a plurality of ribs 16 to 21, and the main beam 1, the auxiliary beam 3, and the support member 2 Since the extrusion directions are aligned and assembled, each mounting wall and the surface to be mounted can be easily brought into surface contact and the contact area can be freely set. Then, the first mounting wall 16 of the support arm 2 is brought into surface contact with the lower surface of the main beam 1 and mechanically fixed to the main beam 1 with the bracket 22 from below, so that stable high mounting strength and stable at the time of collision are achieved. A predictable load displacement is obtained. Further, by mechanically fixing with the bracket 22, for example, the mounting strength can be appropriately adjusted by adjusting the thickness of the bracket 22, the number of fastening points, and the like, and the load displacement at the time of collision can be easily adjusted.
Further, by fixing the third mounting wall 15a in surface contact with the back surface of the main beam 1, the mounting strength and the load displacement at the time of collision can be adjusted.

In the above example, a pair of left and right support beams 2 are provided. However, additional support beams such as one at the center in the width direction or one at the left and right can be provided as necessary. In the above example, the left and right portions of the bracket 22 are fastened with bolts and nuts. However, in order to adjust the mounting strength and load displacement at the time of collision, for example, the left and right portions can be fastened, or the bolts and nuts can be fastened. Other fastening elements (for example, rivets and the like) can be used as appropriate. This also applies to the case of joining the third mounting wall 15a.
In the above example, the second mounting wall 22 of the support arm 2 and the back surface of the auxiliary beam 3 are fastened by bolts and nuts, but may be joined by other fastening elements or welding.
In the above example, the third mounting wall 15a of the support arm 2 and the back surface of the main beam 1 are fastened with bolts and nuts. However, the joining of the third mounting wall 15a and the main beam 1 is auxiliary, and is essential. Absent.

  Various aluminum alloys can be used for the main beam 1, the support arm 2, the auxiliary beam 3, and the bracket 22. Among them, a relatively high-strength JIS 7000 series aluminum alloy is used as the support beam 2 and the auxiliary beam 3. As the bracket 22, for example, a 6000 series aluminum alloy such as JIS6063 is suitable.

It is a top view of the bumper structure concerning the present invention. It is II-II sectional drawing of FIG. FIG. 3 is a left side view of FIG. 2. It is sectional drawing which shows the other example of the fastening structure of the main beam and support arm of the bumper structure which concerns on this invention. It is sectional drawing (a cut location is the same as FIG. 2) of the bumper structure which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Main beam 2 Support arm 3 Auxiliary beam 14 Front wall 15 of support arm Rear wall 15a of support arm Projection wall (third attachment wall) of support arm
16 Rib wall of support arm (first mounting wall)
17-20 Rib wall 21 of support arm Rib wall of support arm (second mounting wall)

Claims (6)

In an automobile bumper structure comprising a main beam, left and right support arms whose upper ends are fixed to the main beam, and auxiliary beams fixed to the lower end of the support arm and positioned below the main beam, The main beam, the auxiliary beam, and the support arm are all made of an aluminum alloy extruded shape, and the support arm is arranged so that the cross section is hollow and the extrusion direction is parallel to the longitudinal direction of the main beam and auxiliary beam A first mounting wall located at the upper end of the contour of the hollow section abuts the lower surface of the main beam, and a bracket longer than the width of the support arm in the pushing direction passes through the hollow section and is arranged along the pushing direction of the support arm. A central portion thereof is in contact with the lower surface of the first mounting wall, and both left and right sides are in contact with the lower surface of the main beam and are joined to the main beam by a fastening element; The automobile bumper structure second mounting wall positioned near the lower end of the contour of the hollow cross-section is characterized in that it is joined to the auxiliary beams in contact with the installation surface of the auxiliary beam. The automobile bumper structure according to claim 1, wherein the collision surface of the auxiliary beam is positioned in front of the collision surface of the main beam. The support arm has a third mounting wall protruding above the outline of the hollow cross section, and the third mounting wall is in contact with the back surface of the main beam and joined to the main beam by a fastening element. The bumper structure for an automobile according to claim 1 or 2, wherein the bumper structure is an automobile. 4. The support arm according to claim 1, wherein the support arm has a front wall, a rear wall, and a plurality of rib walls connecting the both walls, and an upper rib wall is the first mounting wall. An automobile bumper structure described in any one of the above. The support arm has a front wall, a rear wall, and a plurality of rib walls that connect the two walls. 4. The bumper structure for an automobile according to claim 3, wherein the bumper structure protrudes upward to form the third mounting wall. The outline of the hollow cross section of the support arm is substantially L-shaped, the rib wall formed at the upper end of the substantially L-shaped contour is the first mounting wall, and the front end of the substantially L-shaped contour. The formed rib wall is the second mounting wall, and the second mounting wall is in contact with the back surface of the auxiliary beam and joined to the auxiliary beam. Car bumper structure.

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