JPH1111239A - Energy absorbing structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase an energy absorbing amount and improve a productivity. SOLUTION: Plural projections 30 are formed facing to a vehicular front side on resin sheets 24, 26, 28 for constituting a bumper reinforcement 12 and the forming patterns of the projections 30 of the resin sheets 24, 26, 28 are same. The 4 way side walls 30A of the projections 30 of the resin sheets 24, 26, 28 are expanded in a taper shape facing to a vehicular rear side and respective projections 30 are formed in a trapezoid. The projections 30 are piled each other on the axis 34 of the projections 30 coaxially and in an energy absorbing direction (vehicular front/rear direction). Step differences 30B are formed on the intermediate part of the vehicular front/rear direction of the 4 way side walls 30A of the projections 30. The top surface 30C of the rear projection 30 is contacted with the step difference 30B and an air room 36 is formed by the piled front/rear projections 30.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an energy absorbing structure, and more particularly to an energy absorbing structure used as a bumper reinforcement for a vehicle.

[0002]

2. Description of the Related Art Conventionally, an energy absorbing structure has been used for bumper reinforcement of a vehicle such as an automobile.
No. 55893.

As shown in FIG. 8, this energy absorbing structure has a first core member 102 and a second core member 104 as bumper reinforcement inside a face portion 100 of a bumper. First core member 102, second core member 104, and face portion 1
00 is each made of a thermoplastic material. The first core member 102 and the second core member 10
4 and a plurality of ribs 100 on each of the face portions 100.
A, 102A, 102B, 104A are formed,
These ribs 100A, 102A, 102B, 104A
A plurality of cells having a closed cross-sectional shape are formed by joining the two to each other by means of heat welding.

[0004]

However, in this energy absorbing structure, a plurality of cells having a closed cross-sectional shape buckle due to a compressive load at the time of collision, and the load characteristic has a peak just before buckling of the cell. A characteristic occurs in which a load is generated and then sharply decreases. As a result, the amount of energy absorption tends to decrease. Further, in this energy absorbing structure, in order to form a plurality of ribs, it is necessary to use a resin material having considerably high moldability and also to considerably increase the molding pressure, so that productivity is not good.

The present invention has been made in view of the above circumstances, and has as its object to obtain an energy absorbing structure capable of increasing the amount of energy absorption and improving the productivity.

[0006]

According to a first aspect of the present invention, there is provided an energy absorbing structure formed by laminating a plurality of resin sheet materials, wherein the plurality of sheet materials are:
A projection having a tapered side wall is provided, and the other projection inserted into the projection abuts on the inside of the side wall of one projection that is coaxial and overlaps in the same direction.

[0007] Therefore, when the convex portion receives an impact from the axial direction, one convex portion that is coaxial and overlaps in the same direction enters into the other convex portion. For this reason, the side wall portion of the entered convex portion is plastically deformed, and this deformation acts as a resistance to the entry of the convex portion, and the impact is absorbed. Further, since it is only necessary to form a convex portion having a tapered side wall on the sheet material, the sheet material can be easily removed from the molding die, and productivity can be improved.

According to a second aspect of the present invention, in the energy absorbing structure according to the first aspect, an air chamber is formed by the overlapping convex portions.

Accordingly, the air confined in the air chamber between the two overlapping projections is compressed by the entry of one of the projections, and the pressure in the air chamber rises. This increase in pressure resists the entry of the projections. Acts as a shock absorber.

According to a third aspect of the present invention, in the energy absorbing structure according to the first or second aspect, the formation patterns of the convex portions of the plurality of sheet members are the same.

Therefore, in addition to the contents described in the first aspect, a single mold for molding the sheet material can be used, and the cost can be reduced.

According to a fourth aspect of the present invention, in the energy absorbing structure according to the second or third aspect, one or more orifices are provided on a wall around the air chamber.

Therefore, in addition to the contents described in claim 2 or 3, the pressure in the air chamber rises due to the entry of the one convex portion, and the air in the air chamber is discharged from the orifice with resistance. Therefore, the impact can be absorbed also by this.

According to a fifth aspect of the present invention, in the energy absorbing structure according to the second or third aspect, at least one thin portion is provided on a wall around the air chamber. .

Therefore, in addition to the contents described in claim 2 or claim 3, the pressure in the air chamber is increased by the entry of the one convex portion, and the impact can be absorbed by the resistance of the thin portion to burst.

According to a sixth aspect of the present invention, in the energy absorbing structure according to any one of the first to fifth aspects, a side wall of one of the overlapping convex portions is inserted into the other of the overlapping portions. The present invention is characterized in that a step portion with which the top surface of the convex portion comes into contact is provided.

Therefore, in addition to the contents described in any one of the first to fifth aspects, it is possible to easily position the convex portions overlapping with each other by the step portion, and to plastically deform the step portion when the convex portion enters. Can absorb shock.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the energy absorbing structure of the present invention will be described with reference to FIGS.

In the drawings, the arrow FR indicates the forward direction of the vehicle, and the arrow UP indicates the upward direction of the vehicle. As shown in FIG. 4, the energy absorbing structure according to the first embodiment is applied to a bumper reinforcement 12 of a front bumper 10. The bumper reinforcement 12 is attached to a front end of a pair of left and right front side members 18 provided at a front portion of the vehicle body 16 via a pair of left and right bumper arms 14. In addition, a bumper reinforcement 12 is provided in front of the bumper reinforcement 12.
Is provided.

As shown in FIG. 3, the bumper reinforcement 12 is composed of five long rectangular resin sheets 2.
2, 24, 26, 28, 29 are formed by overlapping in the vehicle front-rear direction. 5 resin sheets 22, 24, 2
Out of 6, 28, and 29, a plurality of convex portions 30 are formed on three resin sheets 24, 26, and 28 as sheet materials disposed in the intermediate portion toward the front side of the vehicle. These protrusions 30 are of two types, a substantially square shape as viewed from the front of the vehicle, and a long shape extending along the vehicle width direction, and the entire surface excluding the fixing portion 32 to the bumper arm. Is formed. In addition, the formation pattern of the convex part 30 of each resin sheet 24, 26, 28 is the same.

As shown in FIG. 2, each resin sheet 24,
The four side walls 30A of the projections 30 of 26 and 28 are tapered toward the rear of the vehicle, and each projection 30 is trapezoidal. The overlapping portions 30 of the resin sheets 24, 26, 28 are disposed on the axis 34 of the projecting portion 30.

As shown in FIG. 1, each resin sheet 24,
The resin sheets 26, 28 are joined to each other by welding, bonding, or the like, and the protruding portions 30 on the same axis of the resin sheets 24, 26, 28 overlap in the energy absorbing direction (vehicle longitudinal direction). In addition, a step portion 30B is formed at an intermediate portion of the four side walls 30A of the convex portion 30 in the vehicle longitudinal direction. The top surface 30C of another convex portion 30 inserted from the vehicle rear side into the convex portion 30 is in contact with the step portion 30B, and the air chamber 36 is formed by the overlapping front and rear convex portions 30. . The air chamber 37 is also formed by the protrusion 30 of the resin sheet 28 and the resin sheet 29.

Five resin sheets 22, 24, 26, 2
8, 29, the resin sheet 2 disposed on the front and rear outer portions
2, 29 are bonded to the resin sheets 24, 23 by welding, adhesion, or the like, and the sandwiched resin sheets 24, 2,
Deformation such as opening of the mouths 6 and 28 is prevented.

Next, the operation of the first embodiment will be described.
In the energy absorbing structure of the first embodiment, a load in the vehicle front-rear direction acts on the bumper reinforcement 12 of the front bumper 10 due to the collision, and the resin sheet 2
When the projections 30 formed on the 4, 26, and 28 receive an impact from the axial direction (vehicle longitudinal direction), when the impact is small, the collision energy is absorbed by the elastic deformation of the resin sheets 24, 26, and 28. . In this case, if the input load due to the impact is within the elastic region of each of the resin sheets 24, 26, and 28, each of the resin sheets 24, 26, and 28 will be restored when the input load is removed, and there is no need for repair.

On the other hand, when the impact is large and the input load due to the impact exceeds the elastic area of each of the resin sheets 24, 26, and 28, the side walls 30A of the front and rear projections 30 joined to each other are connected.
Is subjected to shearing force and peels off, and the impact is absorbed by the peeling. Next, since the side wall 30A of the front convex part 30 resists the approach of the side wall 30A of the rear convex part 30 by the tapered side wall 30A, the impact is also absorbed by the trowel.

At this time, the air confined in the air chambers 36 and 37 is compressed by the entry of the rear convex portion 30 and the pressure in the air chambers 36 and 37 rises. Acts as a resistance to the ingress of water, and the impact is absorbed. Further, the rear convex portion 30 is added to the front convex portion 30.
Enters the side wall 3 of the projection 30 as shown in FIG.
Since 0A and the step portion 30B break, the break acts as resistance against the intrusion of the convex portion 30 and absorbs a large impact.

Therefore, the energy absorbing structure of the first embodiment can stably absorb the energy at the time of collision for a long time.

Further, in the energy absorbing structure of the first embodiment, since the projections 30 may be formed on the resin sheets 24, 26, and 28, the energy absorbing structure can be easily removed from the molding die. As a result, molding can be easily performed without requiring a special molding die. In addition, since the pattern of forming the protrusions 30 of each of the resin sheets 24, 26, and 28 is made the same, a single mold for forming each of the resin sheets 24, 26, and 28 can be used, and the cost can be reduced.

Further, in the energy absorbing structure of the first embodiment, a step 30B is formed at the middle of the four side walls 30A of the protrusion 30 in the vehicle longitudinal direction, and the rear protrusion 30B is formed on the step 30B. Since the top surface 30C is abutted, positioning between the front and rear convex portions 30 can be easily performed by the step portion 30B, and assembling workability is improved.

In the energy absorbing structure of the first embodiment, the energy absorption of the energy absorbing structure is tuned by adjusting the thickness and the number of the resin sheets 24, 26 and 28, the number of the projections 30, The shape of the projection 30, that is,
By changing the vertical length, the horizontal length, the height (the length in the direction of the axis 34), and the like, it can be easily performed.

In the first embodiment, the resin sheets 22 and 29 are provided on the front and rear outer portions of the three resin sheets 24, 26 and 28, respectively.
29 may be omitted. In addition, resin sheet 2
The numbers 4, 26 and 28 are not limited to three, but may be two or four or more. The shape of the projection 30 is not limited to a rectangular shape as viewed from the front of the vehicle, but may be another shape such as a triangle, a polygon, and a circle. Further, the configuration may be such that the protrusions 30 are formed only on predetermined portions of the resin sheet, not on the entire surface of the resin sheet. Further, the pattern of forming the protrusions may be changed for each resin sheet.

Next, a second embodiment of the energy absorbing structure of the present invention will be described with reference to FIG.

The same members as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

As shown in FIG. 6, in the energy absorbing structure of the second embodiment, an orifice 50 is formed substantially at the center of the top surface 30C of the projection 30, and is provided at the forefront. A through hole 52 is formed in the resin sheet 22 at a position facing the orifice 50.

Therefore, in the energy absorbing structure of the second embodiment, the pressure in the air chambers 36 and 37 rises due to the entry of the rear projection 30 into the front projection 30, and the orifice 50 and the through hole Since the air is discharged from the air chambers 52 into the air chambers 36 and 37 with resistance, the impact can be absorbed by the orifice effect.

In the second embodiment, the orifice 50
Is formed substantially at the center of the top surface 30C of the projection 30, but the position at which the orifice 50 is formed is not limited to this, and another position may be used. Further, the orifice 50 may be formed at a plurality of locations.

In place of the orifice 50, as shown in FIG. 7, a thin portion 54 is provided on the top surface 30C of the convex portion 30, and the thin portion 54 bursts due to an increase in the air pressure in the air chambers 36 and 37. A configuration in which a shock is absorbed by resistance may be adopted.

In the above, the present invention has been described in detail with respect to a specific embodiment. However, the present invention is not limited to such an embodiment, and various other embodiments are included in the scope of the present invention. It is clear to a person skilled in the art that is possible. For example, in the present embodiment, the energy absorbing structure of the present invention is applied to the bumper reinforcement of the front bumper.
The present invention is also applicable to a bumper reinforcement of a rear bumper and an energy absorbing unit other than the bumper reinforcement.

[0039]

According to the first aspect of the present invention, there is provided an energy absorbing structure formed by laminating a plurality of resin-made sheet materials, wherein the plurality of sheet materials have a convex portion having a tapered side wall. Since the other protrusion inserted into the protrusion comes into contact with the inside of the side wall of the protrusion which is coaxial and overlaps in the same direction, the amount of energy absorption can be increased and the productivity can be improved. Has the effect.

According to a second aspect of the present invention, in the energy absorbing structure according to the first aspect, the air chamber is formed by the overlapping convex portions. Has an excellent effect that can be increased.

According to a third aspect of the present invention, in the energy absorbing structure according to the first or second aspect, since the formation patterns of the projections of the plurality of sheet members are the same as each other, In addition to the effects described in the item 2, there is an excellent effect that a single mold for forming the sheet material can be used and the cost can be reduced.

According to a fourth aspect of the present invention, in the energy absorbing structure according to the second or third aspect, at least one orifice is provided on a wall around the air chamber.
In addition to the effect described in claim 2 or 3, there is an excellent effect that the amount of energy absorption can be further increased by the orifice effect.

According to a fifth aspect of the present invention, in the energy absorbing structure according to the second or third aspect, at least one thin portion is provided on a wall around the air chamber. In addition to the effect described in the item 3, there is an excellent effect that the energy absorption amount can be further increased by rupture of the thin portion.

According to a sixth aspect of the present invention, in the energy absorbing structure according to any one of the first to fifth aspects, a side wall of one of the overlapping convex portions is provided with the other convex portion inserted inside the convex portion. Since the top surface of the portion is provided with a stepped portion, in addition to the effect according to any one of claims 1 to 5, positioning between the front and rear convex portions can be easily performed, and assembling workability is improved, There is an excellent effect that the amount of energy absorption can be further increased by breaking the step portion.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing an energy absorbing structure according to a first embodiment of the present invention.

FIG. 2 is an exploded side sectional view showing the energy absorbing structure according to the first embodiment of the present invention.

FIG. 3 is an exploded perspective view showing the energy absorbing structure according to the first embodiment of the present invention.

FIG. 4 is an exploded perspective view showing a vehicle having a front bumper to which the energy absorbing structure according to the first embodiment of the present invention is applied, as viewed obliquely from the front.

FIG. 5 is a perspective view showing a deformed state of the energy absorbing structure according to the first embodiment of the present invention, viewed obliquely from the front.

FIG. 6 is a side sectional view showing an energy absorbing structure according to a second embodiment of the present invention.

FIG. 7 is a side sectional view showing an energy absorbing structure according to a modification of the second embodiment of the present invention.

FIG. 8 is an exploded perspective view showing a front bumper to which the energy absorbing structure according to the conventional embodiment is applied, as viewed obliquely from the front.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Front bumper 12 Bumper reinforcement 24 Resin sheet (sheet material) 26 Resin sheet (sheet material) 28 Resin sheet (sheet material) 30 Convex part 30A Four side walls 30B Step part 30C Top surface 34 Convex axis 36 Air chamber 50 Orifice 54 Thin part

Claims (6)

[Claims] 1. An energy absorbing structure formed by laminating a plurality of resin-made sheet materials, wherein the plurality of sheet materials have a convex portion having a tapered side wall and are coaxial and overlap in the same direction. An energy absorbing structure characterized in that the other projection inserted into the projection abuts on the inside of the side wall of the projection. 2. The energy absorbing structure according to claim 1, wherein an air chamber is formed by the overlapping convex portions. 3. The energy absorbing structure according to claim 1, wherein the plurality of sheet members have the same pattern of forming the respective convex portions. 4. The energy absorbing structure according to claim 2, wherein one or more orifices are provided on a wall around the air chamber. 5. The energy absorbing structure according to claim 2, wherein one or more thin portions are provided on a wall around the air chamber. 6. A step according to claim 1, wherein a side wall of one of the overlapping projections is provided with a stepped portion to which the top surface of the other projection inserted into the interior of the projection comes into contact. The energy absorbing structure according to any one of the above.