JPH08170675A - Energy absorbing material - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To provide an energy absorbing member in which debris generated by crushing of an FRP cylinder is clogged to spread the FRP cylinder and prevent a large crack from being generated along the axial direction of the FRP cylinder. [Structure] A V groove 5 is formed in an end portion 2a of the FRP cylinder 2,
The lid 3 is provided with a protrusion 6 that engages with the V groove 5. When an impact force is applied, the protrusion 6 pushes the crack 8 at the tip of the V groove 5, and both sides of the crack 8 are divided into inner and outer portions as fragments 9 and 10. Since there is no protrusion on the lower surface of the lid body 3, the fragments 9,
10 doesn't get stuck anywhere. Therefore, the FRP cylinder 2 is crushed by a constant load, and the energy absorbing member 1 exhibits excellent characteristics.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an energy absorbing member arranged at a portion which receives an impact force and absorbing collision energy.

[0002]

2. Description of the Related Art Generally, an energy absorbing member is attached to a portion such as a front portion of an automobile body that receives an impact in order to absorb collision energy at the time of a collision. Among vehicles requiring such an energy absorbing member, in the case of a passenger car having an engine room in the front, in addition to the cushioning by the energy absorbing member, the parts such as the engine room do not have a very sturdy structure, It is also possible to absorb the collision energy and the impact by the crushing of the vehicle, and to reduce the crushing of the passenger compartment and the impact transmitted to the occupant. However, in a cab-over type truck, a one-box car, or the like, there is no space for crushing in the front part of the vehicle body, and it is difficult to absorb collision energy and impact due to crushing of the vehicle body. In recent years, an energy absorber 11 (hereinafter referred to as an FRP cylinder 11) as shown in FIG. 7 has been attracting attention mainly for the purpose of absorbing the collision energy of an automobile having a structure without such a crushed space.

In general, the energy absorbed by the energy absorber is, as shown in FIG. 8, in the area E of the hatched portion of the diagram showing the relationship between the displacement such as crushing of the energy absorber and the applied load P. Equivalent to. Therefore, the area E of the shaded area is larger and the energy absorbed by the deformation is larger when the load P is not deformed and is deformed. From this point of view, the FRP cylinder 11 shown in FIG. 7 is made of a fiber reinforced plastic (FRP) having a high energy absorption efficiency as a raw material, and the overall shape is a hollow cylindrical shape with both ends open as shown in the figure. The end portion is provided with a taper portion 11a of about 45 degrees by chamfering.

On the other hand, since the FRP cylinder 11 is made of FRP and has the above-mentioned shape as described above, it is difficult to mount the FRP cylinder 11 alone on the vehicle body or the like. Therefore, as shown in FIG. 9, for example, lids 12 and 13 are attached to both ends of the FRP cylinder 11 to form an integrated energy absorbing member 1a, and the lids 13 and 12 are fixed to a frame and a bumper beam and attached to a vehicle body or the like. It is being done. In the case of FIG. 9, the lids 12 and 13 are attached to the FRP cylinder 11 by the protrusion 1 provided on the lids 12 and 13.
2a and 13a are fitted to the FRP cylinder 11 to fix the position in the direction perpendicular to the axis, and the flexible screw rod 14 is inserted between the lids 12 and 13 to fix the position in the axial direction. It is also performed by attaching with an adhesive. 10 and 11 show another example of the lid body on the taper portion 11a side, and the lid body 12b in FIG. 10 is a groove 1 into which the end of the body wall on the taper portion 11a side of the FRP cylinder 11 is inserted.
2c is formed in a circumferential shape, and has a lid 12 of FIG.
Reference numeral d denotes a recess 12e into which the entire end of the FRP cylinder 11 on the side of the tapered portion 11a is fitted. The protrusions 12a and 13a, the groove 12c, and the recess 12 of FIGS.
All of e are for fitting the FRP cylinder 11 and the lid body 12 and the like, and have been indispensable for fixing the position of the lid body 12 and the like in the direction perpendicular to the axis with respect to the FRP cylinder 11. .

[0005]

The FRP cylinder 11 is mounted on the vehicle body or the like with the lids 12 (12b, 12d) and 13 attached as described above. At that time, the FRP cylinder 11 has its shaft. It is installed at the position of the vehicle body where it receives an impact load in the direction. FRP mounted on the vehicle body
When a compressive load P is applied to the cylinder 11, first the taper portion 1
1a breaks as a trigger of breakage, and subsequently, a compressive breakage (hereinafter referred to as crushing) progresses sequentially from the taper portion 11a side toward the other end while generating fragments without buckling the FRP cylinder 11. Begins. On the other hand, the FRP cylinder 11 itself without the lid attached is crushed in a manner as shown in FIG. That is, when a compressive load P is applied, the FRP cylinder 11 tears inward and outward from the approximate center of the wall thickness so that the thick paperboard is delaminated from the approximate center of the wall thickness to the left and right, and the inside of the FRP cylinder 11 is broken. The shards 15 (hereinafter referred to as the inner shards 15) and the shards 16 going to the outside of the FRP cylinder 11 (hereinafter referred to as the outer shards 16) are separated. That is, the inner fragments 15 and the outer fragments 16 are always generated as a pair. On the other hand, in order to fix the position of the lid body 12 or the like in the direction perpendicular to the axis with respect to the FRP cylinder 11 as described above, the protrusions 12a and the like are indispensable. Therefore, the FRP cylinder 1
As shown in FIGS. 9 to 11, the end of the body wall of No. 1 has to be in some form in contact with the portion protruding from the lid body 12 or the like toward the FRP cylinder 11 in a fitting manner. When the crushing of the FRP cylinder 11 starts under such a situation, the following problems occur.

For example, when the FRP cylinder 11 shown in FIG. 9 begins to be crushed, the FRP cylinder 11 itself produces inner fragments 15 and outer fragments 16 as shown in FIG. Of the inner piece 15 and the outer piece 16, the outer piece 16 is shown in FIG.
As shown in FIG. 3, it is possible to smoothly go to the outside of the FRP cylinder 11. This is because there is no projection or the like on the lower surface of the lid body 12 outside the FRP cylinder 11 that hinders the movement of the outer debris. On the other hand, as shown in FIG. 13, the inner debris 15 is prevented from traveling by the protrusion 12a.
However, the starting inner shards 15 are forced to move forward by being pressed by the subsequent inner shards 15, and the FRP cylinder 11 is pushed outward to move forward. As a result, the FRP cylinder 11 is pushed outward. Further, since such an unreasonable forward movement is forced, a part of the inner debris 15 is likely to be clogged and accumulated in the vicinity of the protrusion 12a to be enlarged. When such enlargement occurs, the FRP cylinder 11 is further spread outwardly, and finally a large crack 17 along the axial direction as shown in FIG. 14 is generated in the FRP cylinder 11, and the load P as shown in FIG. However, there is a problem in that it becomes impossible to absorb energy under a constant load due to a sharp decrease. A similar problem occurs in the cases of FIGS. 10 and 11, but the description thereof will be omitted.

As a known technique which seems to be somewhat related to the solution of the above problems, there is JP-A-6-264949. This "energy absorbing member" gradually increases the wall thickness of the FRP cylinder from the crush start end side to the other end side, and has a trumpet shape in which only the vicinity of the crush start end is curved to a small outside, and the FRP is loaded by the axial direction. The cylinder is torn and opens like a petal. However, in this known technique, the FRP cylinder itself is separated into an inner fragment and an outer fragment by a load from the axial direction from the approximate center of the wall pressure, so to speak, such as delamination, in the known technique. There is no awareness of the problem. Therefore, in this known technique, the trumpet-shaped curved portion opens in a petal shape, but the same problem as described with reference to FIGS. 12 to 15 occurs in the tubular portion other than the curved portion, and the FRP cylinder and the lid body FR is clogged with the protrusion of FR
It is understood that the P cylinder is unavoidably expanded and a large crack is formed along the axial direction.

The present invention was devised in order to prevent the above-mentioned problems from occurring when an energy absorbing member is used, and a debris is formed between the FRP cylinder and the downwardly projecting portion of the lid. It is intended to provide an energy absorbing member that prevents clogging of the FRP cylinder and spreads the FRP cylinder to generate a large crack along the axial direction of the FRP cylinder, stably absorbs collision energy, and prevents an occupant from being adversely affected. And

[0009]

In order to achieve the above object, the present invention provides an energy absorbing member having a hollow cylindrical F shape.
An RP cylinder and lids attached to both ends of the FRP cylinder are provided, and a V-shaped V-shaped cross-section is provided at an end of the FRP cylinder.
The groove is provided over the entire circumference of the end portion, and the lid is provided with a protrusion that engages with the V groove.

[0010]

[Function] FRP with V groove formed when impact force is applied
The end of the cylinder triggers the destruction, and the FRP from the lid side
Crushing of the cylinder is started. At that time, the pressing force of the protrusion causes a crack at the tip of the V-shaped groove, and the pressing force applied by the protrusion subsequently causes both side parts of the crack to act as inner fragments and outer fragments without being obstructed by anything. It is divided into the inside and outside of the FRP cylinder.

[0011]

An embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is an axial sectional view of an energy absorbing member 1 of this embodiment, and FIG. 2 is FR which is one of the constituent members of the energy absorbing member 1.
FIG. 3 is a perspective view of the P cylinder 2 and an enlarged axial sectional view of a part thereof, and FIG. 3 is an axial sectional view showing a usage state of the energy absorbing member 1. The energy absorbing member 1 includes an FRP cylinder 2 and an FRP cylinder.
It is composed of lids 3 and 4 attached to both ends of the cylinder 2.
The FRP cylinder 2 of this embodiment is the FRP cylinder 11 shown in FIG.
7 is made of fiber reinforced plastic (FRP) and has a hollow cylindrical body with both ends open.
Unlike the tapered portion 11a of No. 1, a V-shaped groove 5 having a V-shaped axial cross section is formed in a circular shape on the end portion 2a of the FRP cylinder 2 on the side of the fracture start end over the entire circumference of the end portion 2a. A protrusion 6 having a rectangular axial cross-section capable of engaging with the V-shaped groove 5 is formed in a circumferential shape along the edge of the lid 3 on the lid 3 on the side of the fracture starting end of the lids 3 and 4, and the opposite. The lid 4 on the side is provided with a protrusion 4a that can be fitted into the inner hole 2b of the FRP cylinder 2. A flexible screw rod 7 is inserted between the lids 3 and 4, and the screw rod 7
Thus, the lids 3 and 4 are fixed to both ends of the FRP cylinder 2 while the protrusion 6 is engaged with the V groove 5 and the protrusion 4a is fitted in the inner hole 2b.

When an impact force is applied to the energy absorbing member 1 in the axial direction in the state shown in FIG. 1, the end portion 2a of the FRP cylinder 2 which has become thin due to the formation of the V groove 5 becomes a trigger for destruction,
The crushing of the FRP cylinder 2 is started from the lid 3 side. At that time, due to the pressing force of the projection 6 of the lid body 3, as shown in FIG. 3, a crack 8 is generated at the tip of the V-shaped groove 5, and the projection 6 that is pushed in subsequently causes both sides of the crack 8 to move in and out. Be pushed to. Each of the separated pieces is brought into contact with the lid body 3 as curls 9 and 10 once to proceed while curling.
The lower surface of the lid body 3 of the hand of 10 is flat and there is nothing protruding downward. Therefore, there is no possibility that some of the fragments 9 and 10 will be clogged with something, and there is no room for the FRP cylinder 2 to be pushed apart by clogging of some of the fragments 9 and 10. Therefore, the FRP cylinder 2 is shown in FIG.
As shown in (1), it can be stably crushed under a substantially constant load P and can exhibit excellent characteristics as a collision energy absorbing member of an automobile.

5 and 6 respectively show another embodiment of the present invention. In FIG. 5, the projection 6a has a triangular cross section, and in FIG. 6, the projection 6b has a semicircular cross section. It was done. The shape of the protruding portion is not limited to these. The angle of the V groove 5 is not particularly limited, but is 60 to 12
0 degree is appropriate. Further, the material of the FRP cylinder 2 is not limited to the types of reinforcing fiber and matrix resin,
The type of molding method for the FRP cylinder 2 is not limited.

[0014]

The V-groove having a V-shaped axial cross section is provided at the end of the FRP cylinder over the entire circumference, and the protrusion engaging with the V-groove is provided on the lid, so that when an impact force is applied, V
The end of the cylindrical wall where the groove is formed triggers the destruction,
The crushing of the FRP cylinder is started. At that time, a crack is generated at the tip of the V groove due to the pressing force of the projection, and both sides of the crack are divided into the inside and outside by the pressing force applied by the projection, and the FRP cylinder as a fragment without being obstructed by anything. You can go in and out. As a result, the FRP cylinder can be crushed under a substantially constant load, and can exhibit excellent characteristics as a collision energy absorbing member for automobiles.

[Brief description of drawings]

FIG. 1 is an axial sectional view of an embodiment of the present invention.

FIG. 2 is a perspective view and a partially cutaway enlarged axial sectional view of an FRP cylinder which is one of the constituent members of the embodiment.

FIG. 3 is an axial cross-sectional view showing a usage state of the same embodiment.

FIG. 4 is a crushing displacement-load diagram of the embodiment.

FIG. 5 is a partially cutaway sectional view of another embodiment of the present invention.

FIG. 6 is a partially cutaway sectional view of still another embodiment of the present invention.

FIG. 7 is a perspective view of a conventional FRP cylinder and a partially cutaway enlarged axial sectional view.

FIG. 8 is a diagram showing the amount of energy absorption calculated by general displacement and load.

FIG. 9 is an axial sectional view of an example of a conventional energy absorbing member.

FIG. 10 is a partially cutaway axial sectional view of another conventional energy absorbing member.

FIG. 11 is a partially cutaway axial sectional view of still another conventional energy absorbing member.

FIG. 12 is an axial sectional view showing a collapsed state of the FRP cylinder itself.

FIG. 13 is a partially cutaway axial sectional view showing a collapsed state of a conventional energy absorbing member.

FIG. 14 is a side view showing a problem in crushing a conventional energy absorbing member.

FIG. 15 is a crushing displacement-load diagram of a conventional energy absorbing member.

[Explanation of symbols]

 1 Energy Absorbing Member 2 FRP Cylinder 2a End 2b Inner Hole 3 Lid 4 Lid 4a Projection 5 V Groove 6 Projection 6a Projection 6b Projection 7 Screw Rod 8 Crack 9 Fragment 10 Fragment

Claims (1)

[Claims] 1. A hollow cylindrical FRP cylinder and its FRP
An energy absorbing member comprising: a lid body attached to both ends of a cylinder, wherein a V groove having a V-shaped axial cross section is provided at an end portion of the FRP cylinder over the entire circumference of the end portion, and the lid body is provided. An energy absorbing member, characterized in that a protrusion that engages with the V groove is provided.