JP3473145B2 - Energy absorbing material - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an energy absorbing member which is disposed at a site where an impact force is applied and absorbs collision energy. 2. Description of the Related Art Generally, an energy absorbing member is attached to an impact-receiving portion such as a front portion of a vehicle body of an automobile in order to absorb collision energy at the time of a collision. Among the cars requiring such energy absorbing members, in the case of a passenger car having an engine room in front, in addition to the buffering by the energy absorbing members, the engine room and the like are not made to have a very strong structure. It is also possible to absorb the collision energy and impact by the collapse of the vehicle, thereby reducing the collapse of the passenger compartment and the impact transmitted to the passenger. However, in a cab-over type truck, a one-box vehicle, or the like, there is no space in the front portion of the vehicle body that can be crushed, and it is difficult to absorb the collision energy and the impact due to the crushing of the vehicle body. In recent years, attention has been paid to an energy absorber 11 (hereinafter, referred to as an FRP cylinder 11) as shown in FIG. 7 for the purpose of mainly absorbing the collision energy of a vehicle having no such collapsed space. In general, the energy absorbed by an energy absorber is, as shown in FIG. 8, an area E of a hatched portion of a diagram showing a relationship between displacement such as crushing of the energy absorber and the applied load P. Equivalent to. Therefore, when the load P is deformed without decreasing, the area E of the hatched portion becomes larger, and the energy absorbed by the deformation becomes larger. From this point of view, the FRP cylinder 11 shown in FIG. 7 uses a fiber reinforced plastic (FRP) having a high energy absorption efficiency as a material, and has a hollow cylindrical shape having both ends opened as shown in FIG. An approximately 45-degree tapered portion 11a is provided at the end by chamfering. On the other hand, since the material of the FRP cylinder 11 is FRP as described above and has the above-described shape, it is difficult to attach the FRP cylinder 11 alone to a vehicle body or the like. Therefore, for example, as shown in FIG. 9, lids 12 and 13 are attached to both ends of an 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 mounted on a vehicle body or the like. That being done is done. In the case of FIG. 9, the lids 12 and 13 are attached to the FRP cylinder 11 by the protrusions 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 a flexible screw rod 14 is inserted between the lids 12 and 13 to fix the position in the axial direction. It is also practiced to attach it with an adhesive. 10 and 11 show another example of the lid on the tapered portion 11a side. The lid 12b in FIG. 10 is a groove 1 into which the end of the body wall on the tapered portion 11a side of the FRP cylinder 11 is inserted.
2c is formed in a circumferential shape, and the lid 12c of FIG.
“d” is formed with a concave portion 12e into which the entire end of the FRP cylinder 11 on the taper portion 11a side is fitted. 9 to 11, the protrusions 12a and 13a, the groove 12c, and the recess 12
e is for fitting the FRP cylinder 11 to the lid 12 and the like, and has been considered to be indispensable for fixing the position of the lid 12 and the like to the FRP cylinder 11 in the direction perpendicular to the axis. . [0005] The FRP cylinder 11 is mounted on a vehicle body or the like with the lids 12 (12b, 12d) and 13 attached as described above. Is mounted at a position on the vehicle body that receives an impact load in the axial direction. FRP mounted on the car body etc.
When a compressive load P is applied to the cylinder 11, first, the tapered portion 1
1a is broken as a trigger of destruction, and subsequently, compression destruction (hereinafter referred to as crushing), which proceeds from the tapered portion 11a side to the other end side while generating fragments without buckling of the FRP cylinder 11, is performed. Begin. On the other hand, the FRP cylinder 11 itself without the lid is crushed in a manner as shown in FIG. In other words, when the compressive load P is applied, the FRP cylinder 11 is torn inward and outward from the approximate center of the thickness so that the thick paperboard is delaminated from the approximate center of the thickness to the left and right. The fragments 15 (hereinafter, referred to as inner fragments 15) and the fragments 16 (hereinafter, referred to as outer fragments 16) that go outside the FRP cylinder 11. 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 12 and the like in the direction perpendicular to the axis with respect to the FRP cylinder 11 as described above, the projection 12a and the like are indispensable. Therefore, FRP cylinder 1
As shown in FIGS. 9 to 11, the end of the body wall of 1 has to be fitted in contact with a portion projecting from the lid 12 or the like in the direction of the FRP cylinder 11 in some form. When the crushing of the FRP cylinder 11 starts under such a situation, the following problems occur. For example, when crushing of the FRP cylinder 11 shown in FIG. 9 starts, the FRP cylinder 11 itself generates inner fragments 15 and outer fragments 16 as shown in FIG. Outer pieces 16 of the inner pieces 15 and outer pieces 16 are shown in FIG.
As shown in FIG. 3, it is possible to smoothly go outside the FRP cylinder 11. This is because there is no projection or the like on the lower surface of the lid 12 outside the FRP cylinder 11 that hinders the progress of the outer fragments. On the other hand, as shown in FIG. 13, the inner debris 15 is prevented from advancing by the protrusion 12a.
However, the preceding inner fragment 15 is forced by the subsequent inner fragment 15 to advance, and presses the FRP cylinder 11 outward to advance. As a result, the FRP cylinder 11 is pushed outward. In addition, since such an unreasonable advance is forced, a part of the inner debris 15 is liable to be clogged and accumulated near the protrusion 12a and to be enlarged. When such enlargement occurs, the FRP cylinder 11 is further expanded outward, and finally a large crack 17 is formed in the FRP cylinder 11 along the axial direction as shown in FIG. However, there is a problem that energy can be rapidly reduced to make it impossible to absorb energy with a constant load. Although a similar problem occurs in FIGS. 10 and 11, the description is omitted. [0007] Japanese Patent Application Laid-Open No. Hei 6-264949 is known as a known technique that seems to be slightly related to the solution of the above problem. This “energy absorbing member” gradually increases the thickness of the FRP cylinder from the crushing start end toward the other end, and has a trumpet shape in which only the vicinity of the crushing start end is slightly outwardly curved. The cylinder opens like a petal while being torn. However, according to 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 as if it were delamination, as described above. There is no awareness of the problem. Therefore, in this known technology, 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 cylindrical portion other than the curved portion, and the FRP cylinder and the lid Debris clogs between the protrusions of the FR
It is understood that it is inevitable that the P cylinder is expanded and a large crack is generated along the axial direction. SUMMARY OF THE INVENTION The present invention has been made 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 a portion protruding below the lid. An object of the present invention is to provide an energy absorbing member for preventing a large crack from being generated along the axial direction of the FRP cylinder by preventing the FRP cylinder from spreading and expanding the FRP cylinder, stably absorbing the collision energy and preventing the occupant from being adversely affected. And 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, and a V-shaped V-shaped section at the end of the FRP cylinder.
The groove is provided over the entire circumference of the end portion, and the lid is provided with a projection engaging with the V-groove. An FRP with a V-groove formed when an impact force is applied
The end of the cylinder triggers destruction, and the FRP
Crushing of the cylinder begins. At this time, a crack is generated at the tip of the V-groove due to the pressing force of the protrusion, and then both sides of the crack are formed as inner fragments and outer fragments without being hindered by the pressing force applied by the protrusion. Divided into and out of the FRP cylinder. An embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is an axial cross-sectional view of the energy absorbing member 1 of the present embodiment, and FIG.
FIG. 3 is a perspective view of the P cylinder 2 and an enlarged sectional view of a part of the P cylinder 2. FIG. The energy absorbing member 1 includes an FRP cylinder 2 and an FRP
It consists of lids 3, 4 attached to both ends of the cylinder 2.
The FRP cylinder 2 of this embodiment is different from the FRP cylinder 11 shown in FIG.
A hollow cylindrical body made of fiber reinforced plastic (FRP) and having both ends opened as shown in FIG.
Unlike the first tapered portion 11a, a V-shaped groove 5 having a V-shaped axial section is formed in a circular shape at the end 2a on the fracture start end side of the FRP cylinder 2 over the entire circumference of the end 2a. Of the lids 3, 4, a projection 6 having a rectangular cross section that can be engaged with the V-groove 5 is formed circumferentially along the edge of the lid 3 on the lid 3 on the breaking start end side. The lid 4 on the side has a protruding portion 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.
As a result, the lids 3 and 4 are fixed to both ends of the FRP cylinder 2 with the projections 6 meshing with the V-grooves 5 and the projections 4a fitted in the inner holes 2b. When an impact force is applied in the axial direction of the energy absorbing member 1 in the state shown in FIG. 1, the end 2a of the FRP cylinder 2 thinned by 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 this time, a crack 8 is generated at the tip of the V-groove 5 due to the pressing force of the projection 6 of the lid 3 as shown in FIG. Is pushed. Each of the pushed pieces advances as the pieces 9 and 10 curl while contacting the lid 3 once.
The lower surface of the lid 3 of the 10-way is flat and there is nothing protruding downward. Therefore, it is impossible that a part of the fragments 9 and 10 is clogged with something, and there is no possibility that a part of the fragments 9 and 10 are clogged and the FRP cylinder 2 is spread. Therefore, the FRP cylinder 2 is
As shown in (1), it can be crushed stably with a substantially constant load P, and can exhibit excellent characteristics as a collision energy absorbing member of an automobile. 5 and 6 show another embodiment of the present invention. FIG. 5 shows a projection 6a having a triangular axial cross section, and FIG. 6 shows a projection 6b having a semicircular axial cross section. It was done. The shape of the projection is not limited to these. The angle of the V-groove 5 is not particularly limited, but is 60 to 12 degrees.
0 degree is appropriate. Furthermore, the material of the FRP cylinder 2 is not limited to the type of the reinforcing fiber and the matrix resin,
The type of the forming method of the FRP cylinder 2 is not limited. According to the present invention, a V-groove having a V-shape in cross section is provided over the entire circumference at the end of the FRP cylinder, and a projection is provided on the lid to engage with the V-groove. V
The end of the grooved cylindrical wall triggers 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 then both sides of the crack are separated inside and outside by the pressing force applied by the projection, and the FRP cylinder is broken as a fragment without being hindered by anything. Can go in and out of As a result, the FRP cylinder is crushed by a substantially constant load, and can exhibit excellent characteristics as a collision energy absorbing member of an automobile.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an axial sectional view of one 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 sectional view showing a use state of the embodiment. FIG. 4 is a crush 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 a further 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 illustrating energy absorption obtained 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 crushed state of the FRP cylinder itself. FIG. 13 is a partially cutaway axial sectional view showing a crushed 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 crush displacement-load diagram of a conventional energy absorbing member. [Description of Signs] 1 Energy absorbing member 2 FRP cylinder 2a End 2b Inner hole 3 Cover 4 Cover 4a Projection 5 V groove 6 Projection 6a Projection 6b Projection 7 Screw rod 8 Crack 9 Fragment 10 Fragment 10 Fragment

Claims (1)

(57) [Claims 1] A hollow cylindrical FRP cylinder and its FRP
A lid attached to both ends of a cylinder, wherein the V-shaped groove having an V-shaped axial cross section is provided at an end of the FRP cylinder over the entire periphery of the end, and the lid is provided on the lid. An energy absorbing member, wherein a projection is provided for engaging with the V-groove.