JPH1113807A - Shock energy absorbing member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure a uniform and continued pressing burst of an energy absorbing member, in this way, to increase the final amount of whole absorptive energy. SOLUTION: A shock energy absorbing member is divided by at least one surface crossing with a center axis of cylindrical units 12, 13, to have a synthetic resin-made hollow cylindrical structure to be fitted or opposed in a divided surface. In at least one side of an outer or inner side of fitted or opposed part, a belt-shaped unit 14 is provided, and in the fitted or opposed part, a functional structure inducing a pressing burst is provided. The functional structure provided in the fitted or opposed part to induce a pressing burst is formed in wedge shape, in addition, the belt-shaped unit has an opening part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shock-absorbing structural member for absorbing shock energy when an unexpected shock is applied to a vehicle whose load is sensitive to shock energy such as humans, animals, and dangerous goods. is there. More specifically, the present invention relates to an impact energy absorbing member made of a synthetic resin such as a thermoplastic resin obtained by injection molding, which irreversibly absorbs this energy in its own specific failure mode.

[0002]

2. Description of the Related Art With respect to energy absorbing members made of synthetic resin, attention has been paid to the lightness thereof, and many technologies have been proposed mainly for use in vehicles. As the shape, a cylindrical body is often used, and a mechanism is employed in which a compressive load is applied from the axial direction of the cylinder to irreversibly destroy the member, thereby absorbing impact energy.

[0003] It is important that the member be uniformly and continuously destroyed at the time of impact.
No. 49 proposes an energy absorbing member made of a thermoplastic resin, which is characterized by the structure of the end portion and the continuous change in the wall thickness of the cylindrical wall. Here, as pointed out in the above publication, in a simple cylindrical member, the entire cylindrical portion is subject to destruction due to a compressive load, and destruction (buckling) occurs at the weakest portion (usually the central portion) of the cylindrical portion. Occurs, and the cylindrical shape cannot be maintained. As a result, since the load is not propagated to the remaining portion and no continuous destruction is performed, the final overall absorbed energy is at an extremely small level.

[0004] Therefore, in the above-mentioned publication, the energy absorbing member made of a thermoplastic resin cylindrical body characterized by the structure of the end portion and the continuous change in the wall thickness of the cylindrical wall is used to make the member uniform and continuous. It has secured a squeeze.

However, the actual structure of the member described in the above publication is quite complicated as shown in FIGS. 7 to 9 of the publication (the same publication, page 7).

[0006]

That is, the object of the present invention is to provide a cylindrical impact energy absorbing member that ensures uniform and continuous squeezing of the member, thereby achieving a final overall absorption. To improve energy.

[0007]

That is, the first aspect of the present invention is as follows.
The present invention relates to an impact energy absorbing member having a hollow cylindrical structure made of synthetic resin, which is divided at least on one surface intersecting the center axis of the cylindrical body and fitted or opposed at the divided surface.

[0008] A second aspect of the present invention is the first aspect of the present invention.
The present invention relates to an impact energy absorbing member characterized in that a band-shaped body is provided on at least one of an outer side and an inner side of a fitted or opposed portion (hereinafter, simply referred to as a fitted portion).

A third aspect of the present invention is the first or second aspect of the present invention.
The present invention relates to an impact energy absorbing member, characterized in that a functional structure that induces crushing is provided in the fitting portion.

A fourth aspect of the present invention is the third aspect of the present invention,
The present invention relates to an impact energy absorbing member, wherein a functional structure for inducing crushing provided in the fitting portion has a wedge shape.

According to a fifth aspect of the present invention, in the second aspect of the present invention,
The present invention relates to an impact energy absorbing member, wherein the band-shaped body has an opening.

The hollow cylindrical body as the impact energy absorbing member of the present invention is used in a state where the hollow cylindrical body is attached so that a compressive strain is generated from the axial direction of the cylindrical body. The hollow cylindrical body can be made of a synthetic resin made of a thermosetting resin or a thermoplastic resin. It is preferable to use a thermoplastic resin because it is easy to manufacture a cylindrical body by injection molding.

In the present invention, in the impact energy absorbing member made of a synthetic resin made of a tubular body, the tubular body is divided by dividing the tubular body and fitting or opposing each divided portion at the divided surface. However, the presence of the division / fitting surface functions as a function of inducing crushing, and uniform and continuous breaking of the member is ensured. The position of the dividing / fitting surface can be any position in the axial direction as long as a certain distance from the end of the cylindrical body is secured. Usually, the position at the substantially central part of the substantially cylindrical body is preferable. As described above, the central portion is usually the weakest portion, and breakage (buckling) occurs at the central portion, so that the cylindrical shape cannot be maintained. It is preferable that the point where such buckling occurs easily is positively used as a function of inducing crushing, and a dividing / fitting surface is formed substantially at the center.

[0014] Further, by winding a band (band-like body) on the outside and / or inside of the dividing / fitting surface in a band shape, the moving direction of the divided tubular body due to an applied impact is maintained and controlled at the time of crushing. As a result, uniform and continuous destruction of the member is ensured.

In addition, a crush-inducing portion having a specific shape (a portion also referred to as a "trigger") is applied to the dividing / fitting surface so that stress at the time of impact is applied in parallel with the central axis of the cylindrical body.
Can be installed. Specifically, in addition to setting the angle of the division surface with respect to the axis of the cylindrical body to 90 °, forming a diagonal division surface, or making one of the cross-sectional shapes of the division / fitting surfaces into a wedge shape, The fitting surface may be a fitting surface corresponding to the wedge-shaped shape.

In addition, an opening is provided in at least a part of the band which is wound around the outside and / or inside of the dividing / fitting surface so as to prevent the cylindrical body from being broken due to energy absorption. It can be a structure that does not inhibit.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a member of the present invention will be described with reference to the drawings illustrating a method of manufacturing an impact energy absorbing member. FIG. 1 shows one method of manufacturing an energy absorbing member according to the present invention.

Schematically, two thermoplastic resin cylindrical bodies (divided cylindrical bodies) which are formed into two parts at an arbitrary cross section intersecting the center axis of the cylindrical body are divided into respective cylindrical bodies. In a set of molds in which the cores used for the formation are arranged on different sides, the thermoplastic resin is molded separately by primary injection at the same time, and then one of the molds is moved to form two cylindrical It is manufactured by fitting or opposing the bodies so as to be in contact with each other on the divided surface, and forming a belt-like body surrounding the fitting portion by secondary injection.

More specifically, as shown in FIG. 1 (a), first, a divided cylindrical body 1 and a divided cylindrical body 2 are molded by primary injection of a thermoplastic resin, and thereafter, FIG. Each arrow 2 inside
1 by moving the mold 4 in the direction shown in FIG.
The divided tubular bodies 1 and 2 are opposed to each other as shown in FIG. At this time, the concave portion 3a of the mold 3 and the concave portion 4 of the mold 4
secondary injection of resin into the cavity defined by
The strip 5 is formed.

As is apparent from this manufacturing method, the structure of the hollow cylindrical body of the energy absorbing member is such that the sectional shapes of the divided cylindrical body 1 and the divided cylindrical body 2 can be fitted or opposed. Can be set arbitrarily. For example, when the cylindrical body is a cylinder, the cross-sectional shape can be arbitrarily set from a circle, an ellipse, a polygon, a star, and the like, or a combination thereof. The structure of the entire cylindrical body may be a structure in which the wall thickness is arbitrarily changed, or a bottomed structure in which a bottom plate is provided on the cylindrical body.

In the example of FIG. 1, the molds 3 and 4 are commonly used for forming the divided tubular portion and the belt-shaped body, but completely different molds may be used.

Although not shown, Japanese Patent Publication No. 2-38377.
As described in the publication, a cavity constituted by the concave portion 3a and the concave portion 4a is provided inside the divided cylindrical body, and the band 5 is formed in the divided cylindrical body by secondary injection into the cavity. It can also be done.

Here, including the molding method shown in FIG. 1, after forming the divided cylindrical body by primary injection using a divided mold,
In the method of forming a band by moving the split mold and performing the second injection again, the band formed later may be fused to the cylindrical body. When the band is completely fused to the divided tubular body, the divided tubular body may be integrated, so that the significance of dividing the tubular body may be reduced. However, usually, after the primary injection, the secondary injection is performed after the divided cylindrical body is sufficiently cooled, or the type of the resin is changed between the primary injection and the secondary injection (the melting point of the resin is changed). Can be easily reduced to such a degree that the divided tubular body and the belt-like body are not substantially fused to each other. Since the divided surfaces of the divided cylindrical body do not fuse with each other, it is possible to positively fuse the band to the cylindrical body depending on the shape of the cylindrical body or the band.

The structure of the fitting portion is "divided cylindrical body 1 and mold 4".
And the combination (the specific shape is not shown) of the "split cylindrical body 2 and the mold 3" can be arbitrarily set from a combination of a trigger and a known structure that causes crushing of the trigger. . 2A and 2B are cross-sectional views illustrating the structure of such a fitting portion. In the figure, 6, 7
Reference numerals 9 and 10 denote divided tubular bodies constituting the tubular body, and reference numerals 8 and 10 denote strips.

The angle formed by the divided surface with respect to the central axis of the cylindrical body can be set arbitrarily such as an oblique direction other than 90 °. FIG. 3 illustrates a case where the angle is set in an oblique direction. In the figure, 12 and 13 are divided tubular bodies, and 14 is a belt-shaped body.

The fitting of the divided cylinders is preferably performed after the solidification of the respective divided cylinders has progressed to some extent so that the divided cylinders are not thermally fused to each other and the function of the trigger is impaired.

As shown in FIGS. 2, 3, 4 and 5,
The strips 8, 11, 14, 16, 17 surrounding the fitting portion are used to avoid such a problem of fusion and to control the direction of movement of the tubular body to prevent the impact applied to the energy absorbing member. Is formed as a mechanism for correcting the direction of the trigger as much as possible in a direction that causes the crushing of the trigger. This strip can be formed by secondary injection, as described above with reference to FIG.

As shown in FIG. 4, the band-shaped body is provided with an opening 17 in a part thereof, and can be structured so as not to hinder the destruction of the cylindrical body 15 due to energy absorption.
Further, as shown in FIG. 5, the band 17 on the side of the divided cylindrical body 19 having the trigger 18 is made thinner, and the band 17 on the side of the divided cylindrical body 21 to which stress is applied is made thicker, so that The reinforcing material may be a reinforcing material that does not hinder the deformation and applies the stress.

[0029]

As described above, according to the present invention, the cylindrical body is formed by dividing and fitting the cylindrical body. It functions as an inducing function and can ensure uniform and continuous destruction of the energy absorbing member.

Further, by winding a band (band-like body) on the outside and / or inside of the dividing / fitting surface in a band shape, the moving direction of the divided tubular body due to an applied impact at the time of crush can be maintained. Controllable and more uniform and continuous destruction of the energy absorbing member can be ensured.

Further, the dividing / fitting surface is set at 90 ° with respect to the axis.
Angle, or a diagonal dividing surface, or one of the cross-sectional shape of the dividing and fitting surface is wedge-shaped,
By forming the other corresponding division / fitting surface as a fitting surface corresponding to the wedge-shaped shape, it is possible to apply stress at the time of impact in parallel with the central axis of the cylindrical body.

In addition, by winding a belt-like body on the outside and / or inside of the dividing / fitting surface in a belt shape, it is possible to avoid the problem of fusion between the fitting surfaces, The direction of movement of the trigger can be controlled, so that the direction of the impact applied to the absorbing member can be corrected as much as possible in the direction that causes the crushing of the trigger.

Further, by providing an opening in at least a part of the belt-like body, a structure that does not hinder destruction of the tubular body due to energy absorption can be obtained.

In addition, since the division / fitting surface is provided, even if the material of the cylindrical body is a poorly oriented material such as a short fiber reinforced thermoplastic resin, uniform and continuous destruction is performed. Good impact energy absorption characteristics can be exhibited.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a mold structure for manufacturing an energy absorbing member of the present invention by injection molding.
The mold configuration for the next injection, and (b) shows the mold configuration for the secondary injection.

FIGS. 2A and 2B are cross-sectional views illustrating the structure of a fitting portion of the energy absorbing member of the present invention, wherein FIG. 2A is a fitting portion structure showing a trigger whose cross section is oblique in the axial direction, and FIG. Shows a fitting portion structure showing a wedge-shaped trigger.

FIG. 3 is a view showing a division / fitting portion and a band-shaped body of the energy absorbing member of the present invention when obliquely crossing in the axial direction.

FIG. 4 is a cross-sectional view of a cylindrical body of the energy absorbing member of the present invention, which is cut at a band-shaped body portion when the band-shaped body has an opening.

FIG. 5 is a cross-sectional view of a cylindrical body of the energy absorbing member of the present invention in the case where the energy absorbing member is provided with a band-shaped body having a difference in thickness.

[Explanation of symbols]

1,2,6,7,9,10,12,13,19,21:
Divided cylindrical body, 3,4: mold, 3a, 4a: concave, 5,
8, 11, 14, 16, 22: strip, 17: opening,
18: Trigger.

Claims (2)

[Claims] At least one crossing a central axis of a cylindrical body
An impact energy absorbing member having a hollow cylindrical structure made of synthetic resin which is divided by a surface and fitted or opposed at the divided surface. 2. The impact energy absorbing member according to claim 1, wherein a band is provided on at least one of the outer side and the inner side of the fitted or opposed portion. 3. A function structure for inducing squeezing destruction at a fitting or facing portion is provided.
Or the impact energy absorbing member according to claim 2. 4. The impact energy absorbing member according to claim 3, wherein the functional structure provided in the fitting or the opposing portion for inducing crushing is wedge-shaped. 5. The impact energy absorbing member according to claim 2, wherein the band has an opening.