JPS6325218B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to impact energy absorbing elements used, for example, in bumpers of automobiles and other locations where impact energy is to be absorbed.

Generally, such shock absorbing elements are formed from elastomers that have suitable mechanical properties within the expected temperature range of use.

Conventionally, in this energy absorbing element, absorbers with various three-dimensional structures have been proposed in order to increase the energy absorption efficiency and stably perform the absorption process. For example, US Pat. No. 3,926,463 discloses an impact energy Discloses an absorbing element consisting of a rib extending in the direction in which the impact load is received, that is, the direction of the impact load, and a support for the rib, and in which the cross section of the rib perpendicular to the direction of the impact load is surrounded only by straight lines such as a quadrangle. Further, US Pat. No. 3,995,901 discloses an absorbent element having the above structure in which the cross section of the rib is curved in a waveform.

However, in such shock absorbing elements,
The deformation when subjected to impact is unstable deformation, that is, incomplete buckling deformation (deformation in which all parts of the absorber do not undergo uniform regular buckling deformation), and therefore there is a lot of loss in energy absorption, and the planned However, it has the disadvantage that it cannot absorb the amount of energy that is applied to it, and its restorability is also poor.

As a result of various studies, the present inventor has found that the drawbacks of the above-mentioned prior art are related to the structure of the rib, that is, the cross-sectional shape of the rib in the direction perpendicular to the load, and the thickness of the rib, and that the cross-sectional shape of the rib is as shown in FIG. Only in the case of a circular arc shape and a specific rib thickness t and radius R, the entire absorber or cylinder C undergoes substantially regular buckling deformation (complete buckling deformation) as shown in FIGS. 2 and 3. ) and found that the planned energy could be stably absorbed.

The present invention is based on the fact discovered by the inventors, that is, the cross section perpendicular to the axial direction is arcuate, and 0.03<t/
It is based on the fact that energy absorbing elements with R<0.3 undergo complete buckling deformation.

The above-mentioned complete buckling deformation also occurs in truncated conical bodies, but many such cylindrical bodies or truncated conical bodies are actually used when attached to bumpers and the like. In this case, if a large number of cylindrical bodies are manufactured individually and attached to a bumper, etc., it is difficult to accurately orient each cylindrical body in a predetermined direction, and it is also difficult to align the adjacent intervals of each cylindrical body. If the directions of the cylindrical bodies and the spacing between the cylindrical bodies are irregular, the intended amount of energy cannot be absorbed, and the desired buffering effect is often not achieved.

The present invention has been made in view of the above points, and provides an energy absorbing element in which several cylindrical bodies or truncated conical bodies are connected by a connecting rib or the like to exhibit a good buffering effect. It is.

A shock absorbing device is known in which a large number of cylindrical bodies, that is, cylindrical bodies with a ring-shaped cross section perpendicular to the axis, are arranged in contact with each other. However, when such cylindrical bodies are used in contact with each other, complete buckling deformation occurs. Then, as shown in FIG. 3, the cylindrical bodies expand outward in the radial direction, so that adjacent cylindrical bodies collide with each other and do not undergo complete buckling deformation. Therefore, the distance between adjacent cylindrical bodies must be wide enough so that they do not interfere with each other after complete buckling deformation. However, if the distance is too large, the amount of energy absorption will decrease, so when arranging a large number of cylindrical bodies, it is preferable that the gaps be as close as possible. According to the present invention, since complete buckling deformation is performed, the pattern of the deformation is determined by the material, radius R, and thickness t. Therefore, since the radial expansion after deformation can be predicted in advance, the intervals between the cylindrical bodies can be arranged so as not to impede complete buckling deformation. The form of this arrangement is arbitrary, and may be arranged in a vertical and horizontal cross pattern, or may be arranged in a staggered manner.

When arranging the cylindrical bodies, it is necessary to connect the two cylindrical bodies for the purpose of handling the energy absorbing element and for positioning the cylindrical bodies. However, if a connecting body is provided, it tends to interfere with complete buckling deformation, and often results in non-complete buckling deformation. Therefore, according to the present invention, a connecting rib that is easily deformed as a whole with respect to the cylindrical body is used.

For this purpose, the connecting ribs can be made of a material weaker than the cylindrical body, or if they are integrally molded, that is, they are made of the same material, the thickness of the connecting ribs can be made thinner than the thickness of the cylindrical body, or What is necessary is to connect the cylindrical bodies partially.

Embodiments of the energy absorbing element according to the invention will be described below with reference to the drawings. In the embodiment of the invention shown in FIGS. 4 to 6, the energy absorbing element 10 according to the invention comprises a plurality (six in the illustrated embodiment) of cylindrical bodies 11, each adjacent cylindrical body 11 being They are connected to each other by connecting ribs 12 and 13. A flat support 1 is provided at the end of the cylindrical body 11.
4 is provided. Cylindrical body 11, connecting rib 1
Preferably, the three members 2, 13 and the support 14 are integrally molded from an elastic material such as rubber or plastic. The elastic material is preferably a polyolefin such as ethylene vinyl acetate copolymer. The length of the connecting ribs 12, 13 connecting each cylindrical body, that is, the interval between adjacent cylindrical bodies 11, is set to the distance that allows complete buckling without interfering with each other when the cylindrical bodies 11 buckle, and the height of the connecting ribs. Similarly, it has been experimentally confirmed that the height is preferably about 40% or more of the height of the cylindrical body 11, and may be the same height as the cylindrical body. Regarding the dimensions of each part, for example, the cylindrical body 11
Good experimental results were obtained when the inner diameter was 29 mm and the wall thickness was 3 mm, the thickness of the connecting rib was 1.5 mm to 2.5 mm, and the thickness of the support 14 was 3 mm. Although the heights of the connecting ribs 12 and 13 are different in the illustrated example, they may be the same. That is, the connecting ribs are made dimensionally weak so as not to impede complete buckling deformation of the cylindrical body. Note that 15 is a hole provided in the support 14, and this hole is provided mainly to allow a finger to be inserted for convenience of handling.
It does not need to be provided.

An embodiment of the energy absorbing element according to the present invention is constructed as described above, and the circumferential walls of at least two cylinders made of elastic material are connected by connecting ribs, and the ends are supported by supports, so that each cylinder When assembling the body to a bumper, etc., it can be arranged at a predetermined position, spacing, and directionality, making it possible to assemble the energy absorbing element accurately and easily. The body undergoes complete buckling deformation, exhibiting a good energy absorption effect, and increasing restoring force.
It should be noted that the connecting ribs 12 and 13 need only connect the cylindrical bodies to each other to the extent that they do not prevent complete buckling deformation, and if they are integrally molded, they should be designed to be dimensionally weak but made of material that is physically weak. You can also do it.

Another embodiment of the invention shown in FIG. 7 differs in that the cylindrical body 21 of the energy absorbing element 20 is connected only by connecting ribs 22, 23, and the support in the previous embodiment is omitted. However, the materials and dimensions of the cylindrical body 21 and the ribs 22, 23 are the same as in the previous embodiment. In this embodiment, since the support is omitted, it is easier to manufacture than the energy absorbing element of the previous embodiment, but other effects are substantially the same as those of the previous embodiment.

In another embodiment of the invention shown in FIGS. 8 and 9, the energy absorbing element 30 includes a plurality (four in the illustrated embodiment) of truncated cones 31
and connecting ribs 32 and 33 connecting the peripheral walls of each adjacent cone body 31 and provided at the end of the cone body 31,
It consists of a support 34 that connects the ends of the cone, and the support 34 is provided with holes 35 as appropriate. It is preferable that the truncated cone 31 is formed integrally with the connecting ribs 32, 33 and the support 34. The wall thickness of the cone 31 is the same over the entire height of the cone. In addition, the materials, dimensions, etc. of the truncated cone, connecting ribs, and supports are shown in Figures 4 to 6.
This is similar to the embodiment shown in the figure. Therefore, the cylindrical body in this specification includes a truncated cone as in this embodiment.

The embodiment shown in FIGS. 8 and 9 of the present invention is constructed as described above, and has substantially the same energy absorption effect as the previous embodiment, but in this embodiment, the support of the truncated cone is Since the diameter of the side or base side is large, the cone can be firmly seated on the support, and the cone has a strong waist and can absorb a large amount of energy. In the case of a truncated cone, the pattern of complete buckling deformation differs between the top and bottom, but as long as complete buckling deformation occurs, the effect is the same as that of a cylindrical shape.

In another embodiment shown in FIGS. 10 and 11, the energy absorbing element 40 includes a cylindrical body 4
1. It is composed of connecting ribs 42, 43 and a support 44. The peripheral wall of this cylindrical body 41 becomes thinner from the base, that is, the support 44 side toward the tip. Therefore, the outer proximal end of the peripheral wall is line a, the outer tip is line b, and the inner proximal end is line c.
In this case, the inner tip is represented by the line d, and length>length. In addition, in the illustrated example, the cross section of the peripheral wall is
It has an elongated trapezoidal shape, and the center line connecting the centers of each length is parallel to the center of the cylindrical body 41. The cylindrical body 41 may be a truncated cone, and the wall thickness at the base and the tip may be changed.

With this configuration, the cylindrical body becomes thicker toward the base side, becomes stronger, and absorbs more energy.

In the embodiment shown in FIGS. 12 and 13, the energy absorbing elements are first and second two.
This is an example of one consisting of two absorbers;
Figure 2 shows the first absorbent element. The first energy absorber 50 includes a plurality of cylindrical bodies 51, connecting ribs 52 and 53 that connect the cylindrical bodies 51, and a support 54 that connects the bases of the cylindrical bodies 51. In the illustrated example, the thickness of the peripheral wall of the cylindrical body 51 becomes thinner from the base to the tip, as in FIG.
They may have the same thickness as shown in FIG. The second energy absorber 60 consists of a plurality of truncated cones 61 and a support 62 connecting the bases of the cones 61. The thickness of the peripheral wall of the truncated cone body 61 is determined in the same manner as the cylindrical body 51. A truncated cone body 6 is placed inside the cylindrical body 51.
1, the first and second energy absorbers 50, 60 are combined to form an energy absorbing element. The second combined with the cylindrical body 51
A cylindrical body can also be used as the energy absorber.

In the above embodiment, since the truncated cone of the second energy absorber is fitted into the cylindrical body of the first energy absorber, the amount of energy absorbed is increased compared to using each energy absorber alone. . Also, the amount of energy that can be absorbed by both energy absorbers is 1
If energy absorption is attempted using separate energy absorbers, the thickness of the peripheral wall becomes considerably thick, making buckling difficult. However, in this embodiment, the first and second energy absorbers can be made relatively thin and have a good Buckling can be performed. Also second
The energy absorber support 62 can be omitted.

Note that the energy absorbing element having a cylindrical body shown in FIGS. 1 to 3 may be combined with another energy absorbing element having a cylindrical body that fits into the cylindrical body as shown in FIG. 12.

In this way, when the first and second energy absorbers are superimposed to form a double structure, it is necessary to design the structure so that the complete buckling deformation patterns of both overlap and do not interfere with each other.

As described above, according to the present invention, since it is composed of a cylindrical body and undergoes complete buckling deformation, it absorbs a large amount of energy, and the amount can be predicted by calculation in advance, and has a restoring force. It is highly suitable as an energy absorbing element such as a bumper. Furthermore, since it can be made by integrally molding an elastic material, it is easy to manufacture.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a cylindrical body for explaining the principle of the present invention, FIGS. 2 and 3 are views showing the buckled state of the cylindrical body, and FIG. 4 is an illustration of an energy absorbing element according to the present invention. FIG. 5 is a front view thereof, FIG. 6 is a side view thereof, FIG. 7 is a plan view showing another embodiment of the present invention, and FIG. 8 is an embodiment of an energy absorbing element. FIG. 9 is a side view thereof, FIG. 10 is a plan view showing another embodiment, and FIG. 11 is a plan view showing another embodiment.
The figure is a side view, FIG. 12 is a plan view of a first energy absorbing element which is still another embodiment, and FIG. 13 is a combination of the first energy absorbing element shown in FIG. 12 with a second energy absorbing element. FIG. 11, 21, 31, 41, 51, 61... Cylindrical body, 12, 13, 22, 23, 32, 33, 4
2, 43, 52, 53...Connection rib, 14, 34,
44,54...Support.

Claims (1)

[Claims] 1. Consisting of at least two cylindrical bodies made of an elastic material such as plastic and a connecting rib, the connecting rib being more deformable than the cylindrical bodies and capable of completely buckling each cylindrical body. An energy absorbing element characterized in that cylindrical bodies are connected at intervals that do not hinder deformation. 2. The energy absorbing element according to claim 1, wherein the bases of at least two cylindrical bodies are provided with a plate-shaped support that connects each cylindrical body. 3. The energy absorbing element according to claim 1, wherein the cylindrical body is a truncated cone. 4. The energy absorbing element according to claim 3, wherein the thickness of the peripheral wall of the cylindrical body becomes thinner from the base toward the tip. 5. The method according to claim 3 or 4, characterized in that the bases of at least two truncated cones are provided with a plate-shaped support that connects each truncated cone. Energy absorbing element. 6. The energy source according to any one of claims 3 to 5, wherein each cylindrical body or truncated cone is fitted with another cylindrical body or truncated cone. absorption element.