JP6741337B2 - Energy absorber - Google Patents

Description

The present invention relates to an energy absorber mounted on a vehicle body for absorbing collision energy.

An energy absorber for absorbing collision energy at the time of a collision is mounted on an automobile body. This type of energy absorber is made up of a hollow body having a closed cross section (in other words, a hollow cylindrical body), and is arranged, for example, in a front bumper. Then, when collision energy is applied to the front bumper, the front bumper is subjected to the action of compressive force and is sequentially destroyed. Collision energy is absorbed by this sequential destruction.

If the energy absorber is hard to break, the collision energy is not sufficiently absorbed. In order to avoid such a situation, many energy absorbers are provided with a trigger at the longitudinal end on the side where the collision energy is applied. In this case, the trigger is the starting point and the destruction progresses sequentially. In short, since the energy absorber is easily destroyed, it becomes easy to absorb the collision energy. The trigger is formed, for example, as described in Patent Documents 1 and 2, as a tapered diameter-reduced portion whose one end in the longitudinal direction is tapered toward the tip.

Among the energy absorbers, for example, as described in Patent Documents 3 and 4, there is one in which a flange portion is formed at each end in the longitudinal direction. One of the flange portions is for connecting the energy absorber to the body frame, and the other flange portion is for connecting to the bumper beam. That is, through holes are formed through the two flange portions, the bolts passed through the through holes are further passed through bolt holes formed in the body frame or the bumper beam, and then the nuts are screwed.

Japanese Unexamined Patent Publication No. 2006-125531 (see particularly FIGS. 1 and 2) JP-A-8-177921 (see particularly FIG. 1) Japanese Unexamined Patent Publication No. 10-169683 (see especially FIGS. 1 and 2) Japanese Patent Laid-Open No. 11-351300 (see especially FIGS. 1 and 2)

As is clear from FIGS. 1 and 2 of Patent Documents 3 and 4, a trigger cannot be provided in the energy absorber having the flange portion. Therefore, in this case, there is a concern that the collision energy may be less likely to be absorbed than the energy absorber provided with the trigger.

The present invention has been made to solve the above-mentioned problems, and provides a energy absorber that is easy to mount on an automobile body because a flange portion is formed and easily causes successive destruction. With the goal.

In order to achieve the above object, the present invention provides a main body which is made of a fiber reinforced resin and is a hollow body having a closed cross section, and a first flange portion which is integrally formed at each end in the longitudinal direction of the main body. , An energy absorber provided with a second flange portion and mounted on an automobile body,
The first flange portion is connected to a first member forming the vehicle body so as to extend rearward of the vehicle body so as to extend substantially parallel to the vehicle width direction of the vehicle body.
Further, the second flange portion is connected to a second member constituting the vehicle body so as to extend in a direction inclined with respect to the vehicle width direction of the vehicle body and faces the front of the vehicle body. Is characterized by.

That is, the energy absorber according to the present invention has the first flange portion and the second flange portion. Therefore, it is easy to connect the energy absorber to a predetermined member.

The energy absorber is attached such that the second flange portion facing the front of the vehicle body is inclined with respect to the vehicle width direction. For this purpose, the second flange portion may be provided on the main body portion so as to be inclined with respect to the horizontal direction. Further, even when the second flange portion is provided on the main body portion so as to be parallel to the horizontal direction, it is possible to incline the second flange portion with respect to the vehicle width direction at the time of attachment to the vehicle body. Any configuration will do. In the latter case, for example, the first flange portion may be inclined with respect to the vehicle width direction.

In this way, by inclining the second flange portion with respect to the vehicle width direction, the base end portion of the second flange portion serves as a trigger to facilitate successive destruction. As a result, the collision energy that can be absorbed increases.

In this configuration, the inclination angle of the second flange portion with respect to the vehicle width direction of the automobile body is preferably within the range of 3° to 30°. If it is less than 3°, the above effect is not sufficient. Further, if it exceeds 30°, it is necessary to largely bend the first member, but such excessive bending is not easy.

In addition, it is preferable to provide an expanding portion having a shape that gradually expands from the main body portion toward the second flange portion, between the main body portion and the second flange portion. In this case, the initial load can be reduced and the collision energy that can be absorbed is further increased.

When the expanding portion is provided, it is preferable that the intersecting angle between the main body portion and the expanding portion be within the range of 15° to 45°. Within this range, the difference between the initial load (maximum load) and the average load becomes small, and the properties suitable as an energy absorber are exhibited.

When the expanding portion is provided, the opening on the second flange portion side is wider than when the expanding portion is not provided. Therefore, when a through hole such as a bolt hole is formed in the second flange portion, the distance between the through hole and the opening becomes small. For this reason, when there is a concern that the strength of the second flange portion may be reduced, the expanding portion may not be provided near the through hole. As a result, a sufficient distance is secured between the through hole and the opening, which prevents the strength of the second flange portion from being lowered.

The body portion typically becomes gradually narrower from the first flange portion (vehicle body rear side) toward the second flange portion (vehicle body front side). In other words, it is a focused shape. With such a shape, the compressive force applied from the front side of the vehicle body diffuses when being transmitted toward the rear side of the vehicle body. Therefore, it becomes difficult for the compressive force to reach the rear side of the vehicle body.

According to the present invention, the energy absorber is configured such that the first flange portion is provided at the vehicle body rear side end portion (rear end) of the body portion and the second flange portion is provided at the vehicle body front side end portion (front end). By doing so, it becomes easy to connect the energy absorber to a predetermined member constituting the automobile body.

Moreover, in this energy absorber, the second flange portion facing the front of the vehicle body is attached so as to be inclined with respect to the vehicle width direction. In this structure, the base end portion of the second flange portion serves as a trigger to facilitate successive breakage. Therefore, the collision energy is sufficiently absorbed.

FIG. 6 is a schematic perspective view of an assembly in which the energy absorber according to the embodiment of the present invention is assembled to a front bumper beam that is a second member. It is a general|schematic whole perspective view of the energy absorber which concerns on this Embodiment. It is a longitudinal cross-sectional view of the energy absorber according to the present embodiment. Load-displacement when the front end of the second flange portion is parallel to the horizontal direction and when the inclination angle of the front end of the second flange portion with respect to the horizontal direction is 3° for the energy absorber having no expanded portion It is a curve. It is a load-displacement curve when the angle of inclination of the 2nd flange part to the horizontal direction is 3 degrees about the energy absorber provided with the expansion part and the 2nd flange part. It is a load-displacement curve when the 2nd flange part is made to incline 1 degree, 2 degrees, 3 degrees, or 4 degrees with respect to the horizontal direction about the energy absorber which comprised the expansion part and the 2nd flange part. .. Load-displacement curve when the intersection angle of the expanding portion with respect to the main body portion is 10°, 15°, 45°, 50° or 60° for the energy absorber configured by providing the expanding portion and the second flange portion. Is. It is a schematic whole perspective view of the energy absorber which concerns on another embodiment.

Hereinafter, preferred embodiments of the energy absorber according to the present invention will be described in detail with reference to the accompanying drawings. In the following description and drawings, "front" represents the traveling direction of the automobile body during normal traveling, and "rear" represents the opposite direction. Further, “right” and “left” respectively refer to the right-hand side and the left-hand side of a driver seated in the driver's seat. Furthermore, the longitudinal direction of the automobile body corresponds to the traveling direction (front-rear direction), and the vehicle width direction is a direction orthogonal to the longitudinal direction.

FIG. 1 is a schematic perspective view of an assembly 14 configured by assembling an energy absorber 10 according to the present embodiment to a front bumper beam 12 (second member). For example, two assembly bodies 14 are connected to a side frame (first member) (not shown) to form a front bumper of an automobile body. That is, one end of each of the energy absorbers 10 and 10 is connected to the side frame, while the other end thereof is connected to the front bumper beam 12, so that the energy absorbers 10 and 10 are mounted on the front part of the vehicle body.

2 and 3 are a schematic overall perspective view and a vertical cross-sectional view, respectively, of the energy absorber 10 according to the present embodiment. The energy absorber 10 is made of a single member that integrally includes a first flange portion 20, a main body portion 22, a widening portion 24, and a second flange portion 26. That is, each of the first flange portion 20, the main body portion 22, the expansion portion 24, and the second flange portion 26 is a part of the energy absorber 10. Further, the energy absorber 10 is a hollow body in which an inner hole 27 extending from the first flange portion 20 to the second flange portion 26 is formed.

The first flange portion 20 and the second flange portion 26 are formed at each end of the main body portion 22 in the longitudinal direction. The first flange portion 20 faces the side frame on the rear side of the vehicle body, and the second flange portion 26 faces the front bumper beam 12 on the front side of the vehicle body.

As shown in FIGS. 1 and 2, the first flange portion 20 is formed with a plurality of bolt holes 28 through which bolts (not shown) are inserted. A bolt passed through the bolt hole 28 is passed through another bolt hole formed in the side frame, and a nut (not shown) is screwed into the screw portion exposed from the bolt hole, whereby the energy absorber 10 is inserted. Is connected to the side frame.

In this case, the first flange portion 20 is connected to the side frame so as to extend along the vehicle width direction of the automobile body. That is, the extending direction (projecting direction) of the first flange portion 20 is substantially parallel to the vehicle width direction of the automobile body.

The main body 22 extending along the longitudinal direction of the automobile body is a hollow body having a closed cross section as shown in FIG. In the present embodiment, the main body 22 has a shape that can be approximated to a truncated pyramid obtained by cutting the apex of an octagonal pyramid. Therefore, the main body 22 has eight flat side walls 30. The eight flat side walls 30 become narrower toward the front and are closer to each other, so that the main body portion 22 goes from the first flange portion 20 facing the rear to the second flange portion 26 facing the front. Becomes gradually narrower. In other words, the main body 22 has a shape that converges toward the front end.

The expansion portion 24 is connected to the main body portion 22. In this case, the expansion portion 24 is composed of eight inclined walls 32 that are continuous with each of the eight flat side walls 30 (see FIG. 2 ). Each inclined wall 32 has a trapezoidal shape in which a lower side connected to the main body 22 is short and an upper side connected to the second flange 26 is long. When the inclined walls 32 having such a shape are adjacent to each other, the expanding portion 24 is formed so as to gradually expand from the main body portion 22 toward the second flange portion 26.

An intersecting angle between the main body portion 22 and the expanding portion 24, that is, an intersecting angle θ1 (see FIG. 3) between one flat side wall 30 and one inclined wall 32 is within a range of 15° to 45°. It is preferable. The reason for this will be described later.

The second flange portion 26 is connected to the expanded portion 24. As with the first flange portion 20, a plurality of bolt holes 34 (through holes) are formed through the second flange portion 26. The bolt (not shown) passed through the bolt hole 34 is passed through a bolt hole 36 formed in the front bumper beam 12 (see FIG. 1). Furthermore, the energy absorber 10 is connected to the front bumper beam 12 by screwing a nut (not shown) into the screw portion exposed from the bolt hole 36.

The second flange portion 26 connected to the front bumper beam 12 extends in a direction inclined with respect to the vehicle width direction of the automobile body, as is apparent from FIG. 3. By thus inclining the second flange portion 26 with respect to the vehicle width direction, the base end portion of the second flange portion 26 functions as a trigger, as will be described later.

Note that FIG. 3 shows the energy absorber 10 arranged on the left side of the vehicle body. That is, the 2nd flange part 26 inclines so that the 2nd flange part 26 may go to the back side, as it goes to the left side from the inner side in the vehicle width direction. Similarly, the second flange portion 26 of the energy absorber 10 arranged on the right side inclines so that the second flange portion 26 moves toward the rear side from the inner side in the vehicle width direction toward the right side. .. Therefore, the front bumper beam 12 is curved so that the vehicle width direction middle abdomen is slightly bulged forward as compared to the vehicle width direction outer side (left side and right side). That is, it bends.

The preferable range of the inclination angle θ2 (see FIG. 3) of the second flange portion 26 with respect to the vehicle width direction is 3° to 30°. When it is less than 3°, it becomes easy to function as a trigger. On the other hand, when the angle exceeds 30°, it is necessary to largely bend the front bumper beam 12 when connecting the second flange portion 26 to the front bumper beam 12, but such large bending is not easy.

The energy absorber 10 configured as described above is made of a fiber-reinforced resin containing a reinforcing fiber in a matrix resin. The matrix resin is not particularly limited, but preferable specific examples thereof include polyamide resin, polyvinyl chloride resin, polypropylene resin, styrene resin, acrylonitrile-butadiene-styrene copolymer (ABS) resin, and fluorine. Thermoplastic resins such as resins, polycarbonate resins and acetal resins can be mentioned.

On the other hand, suitable specific examples of the reinforcing fiber include inorganic fibers such as glass fiber and carbon fiber, and organic fibers such as aramid fiber and cellulose fiber. The length of the reinforcing fiber is set to about 10 mm, for example. That is, in the present embodiment, the reinforcing fibers are long reinforcing fibers and are dispersed in the matrix resin. Instead of long reinforcing fibers, short reinforcing fibers having a length of about 1.0 to 2.0 mm may be dispersed.

The energy absorber 10 can be produced, for example, by performing injection molding using a matrix resin containing the above-described reinforcing fibers in advance. In this case, the mold may be opened by moving the mold in a direction orthogonal to the longitudinal direction of the energy absorber 10.

The energy absorber 10 according to the present embodiment is basically configured as described above. Next, its function and effect will be described.

As described above, in the energy absorber 10, the first flange portion 20 is connected to the side frame via the bolt and the second flange portion 26 is connected to the front bumper beam 12 via the bolt, so that It is mounted on the vehicle body. As described above, by providing the first flange portion 20 and the second flange portion 26 on the energy absorber 10, it becomes easy to mount the energy absorber 10 on the vehicle body. In the energy absorber 10, the first flange portion 20 is substantially parallel to the vehicle width direction, and the second flange portion 26 is inclined with respect to the vehicle width direction. Therefore, the energy absorber 10 has the front bumper beam. When attached to 12, the second flange portion 26 is inclined at an inclination angle θ2 with respect to the vehicle width direction.

For example, when performing a pendulum collision test, the striker collides with the front or longitudinal direction of the automobile body at an angle inclined by 30°. At this time, collision energy is applied to the front bumper. Along with this, a compressive force acts on the energy absorber 10.

Here, with respect to the energy absorber having the second flange portion 26 and not having the expanding portion 24, the second flange portion 26 is parallel to the horizontal direction (the inclination angle θ2 with respect to the vehicle width direction is 0°. 4) and the load-displacement curve when the inclination angle θ2 of the second flange portion 26 with respect to the horizontal direction (vehicle width direction) is 3°. The broken line in FIG. 4 represents the case where the inclination angle θ2=0°, and the solid line represents the case where the inclination angle θ2=3°. The load-displacement curve is obtained by performing an impact test on the energy absorber alone, and the same applies thereafter.

From FIG. 4, when the second flange portion 26 is tilted with respect to the horizontal direction (vehicle width direction), the initial load becomes smaller than that in the case where the second flange portion 26 is parallel, and the area within the curve of the initial load is calculated. It can be seen that the initial absorbed energies taken are approximately equal. This means that the initial absorbed energy can be maintained while reducing the compressive force exerted on the interior of the vehicle body.

In each case, the front end of the main body portion 22 was only buckled, and sequential breakage such as crushing did not occur.

Next, regarding the energy absorber 10 provided with the expansion portion 24 and the second flange portion 26, the load-displacement curve when the inclination angle θ2 of the second flange portion 26 with respect to the horizontal direction (vehicle width direction) is 3°. Is shown in FIG. In this case, it is recognized that successive destructions occur, and from FIG. 5, it is understood that the absorbed energy when the displacement has a relatively large value is sufficiently large.

Furthermore, regarding the energy absorber 10 configured by providing the expanding portion 24 and the second flange portion 26, the second flange portion 26 is 1°, 2°, 3° or 4° with respect to the horizontal direction (vehicle width direction). The load-displacement curve when tilted (the tilt angle θ2 is 1°, 2°, 3° or 4°) is also shown in FIG. The intersection angle θ1 of the expanding portion 24 with respect to the main body portion 22 is 45°.

With reference to FIGS. 4 to 6 together, the energy absorber 10 provided with the expanding portion 24 and the second flange portion 26 is inclined with respect to the horizontal direction (vehicle width direction) of the second flange portion 26. Thus, it can be seen that the initial load can be made small and the absorbed energy when the displacement has a relatively large value can be made sufficiently large. That is, in this case, it becomes easy for successive fractures to occur from the base end of the second flange 26 as a starting point, and it is possible to sufficiently absorb the collision energy.

It can also be seen from FIG. 6 that the initial load (maximum load) becomes a value close to the average load when the inclination angle θ2 is 3° or more. Generally, it is recognized that a material having a small difference between the maximum load and the average load is suitable as the energy absorber 10, and from this fact, it is determined that the inclination angle θ2 is 3° or more. It

However, when the inclination angle θ2 becomes excessively large, it becomes necessary to largely bend the front bumper beam 12 as described above. In order to avoid this, it is preferable to set the inclination angle θ2 to 30° or less.

Further, in the energy absorber 10 configured by providing the expanding portion 24 and the second flange portion 26 in FIG. 7, the intersection angle θ1 of the expanding portion 24 with respect to the main body portion 22 is 10°, 15°, 45°, 50. The load-displacement curve when the angle is 60° or 60° is also shown in FIG. 7. The inclination angle θ2 of the second flange portion 26 with respect to the horizontal direction is 45°.

From FIG. 7, when the intersection angle θ1 is 15° or 45°, the initial load (maximum load) and the average load are substantially equal. That is, the difference between the maximum load and the average load becomes small. From this, it is more preferable to set the intersection angle θ1 within the range of 15° to 45°.

As described above, the second flange portion 26 is provided at the front end of the main body portion 22, the second flange portion 26 is inclined with respect to the vehicle width direction, and further, the second flange portion 26 is expanded between the main body portion 22 and the second flange portion 26. It is clear that the interposition of the portion 24 makes it possible to obtain the energy absorber 10 which is likely to be successively destroyed, which can reduce the initial load and can sufficiently absorb the collision energy.

The present invention is not particularly limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.

For example, the main body 22 may have a shape that can approximate a polygonal pyramid other than an octagonal pyramid, or a truncated pyramid obtained by cutting the top of a cone.

Further, the expanding portion 24 does not need to intervene over the entire area between the main body portion 22 and the second flange portion 26. For example, as shown in FIG. 8, the energy absorber 40 may be configured such that the expanding portion 24 is not provided in the vicinity of the bolt hole 34 (through hole) of the second flange portion 26. In this case, since the distance between the opening of the inner hole 27 and the bolt hole 34 becomes large, there is an advantage that the strength of the second flange portion 26 can be secured.

Further, the first flange portion 20 is provided so as to be inclined in a direction (width direction) orthogonal to the longitudinal direction of the main body portion 22, and the second flange portion 26 is substantially parallel to the width direction of the main body portion 22. The first flange portion 20 may be provided and connected to the side frame so that the first flange portion 20 is substantially parallel to the vehicle width direction. Even in this case, the second flange portion 26 is inclined with respect to the vehicle width direction.

10, 40... Energy absorber 12... Front bumper beam 14... Assembly 20... First flange portion 22... Main body portion 24... Expanding portion 26... Second flange portion 27... Inner hole 30... Flat side wall 32... Inclined wall

Claims (4)

A main body made of fiber reinforced resin and having a closed cross-section hollow body, and a first flange portion and a second flange portion integrally formed at each end portion in the longitudinal direction of the main body portion and mounted on an automobile body. In the energy absorber
The first flange portion is connected to a first member forming the vehicle body so as to extend rearward of the vehicle body so as to extend substantially parallel to the vehicle width direction of the vehicle body.
Further, the second flange portion is connected to a second member constituting the vehicle body so as to extend in a direction inclined with respect to the vehicle width direction of the vehicle body, and faces the front of the vehicle body,
Between the main body portion and the second flange portion, an expansion portion having a shape that gradually expands from the main body portion toward the second flange portion is interposed,
An energy absorber, wherein a through hole is formed in the second flange portion, and the expanding portion is not provided near the through hole. The energy absorber according to claim 1, wherein an inclination angle of the second flange portion with respect to a vehicle width direction of the automobile body is within a range of 3° to 30°. The energy absorber according to claim 1 or 2, wherein an intersecting angle between the main body portion and the expanding portion is within a range of 15° to 45°. The energy absorber according to any one of claims 1 to 3, wherein the main body portion gradually narrows in width from the first flange portion toward the second flange portion. Absorber.

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