JPH07228143A - Impact energy absorber and automobile door trim using this impact energy absorber - Google Patents

Abstract

PURPOSE:To prevent cracking in the case of the impact load speed being large so as to make repeated use possible by forming a block-shaped impact energy absorber of an elastic body of such constitution that plural projecting plate parts with the tip parts larger in wall thickness than the center part are formed in the state of projecting radially with the impact direction as the center axis, and forming the front face of this impact energy absorber into the fitting face to a fitted member. CONSTITUTION:An absorber body 1 formed of an elastic body made of thermoplastic foam resin or the like is of such block shape that four projecting plate parts 2 with the tip parts larger in wall thickness than the center part are formed in the state of projecting radially and uniformly with the impact direction as the center axis and that the front face is formed into the fitting face 1a corresponding to the fitted face shape of a door internal trim base, a fitted member, while the rear face is formed into the receiving face 1b. This absorber body 1 is formed by foaming with primary foam beads such as polypropylene resin as raw material so as to be able to display load-distortion characteristics while attaining light weight. The projecting plate parts 2 display a stable impact absorbing characteristic without the generation of damage and cracks in the case of load over the elastic limit being applied thereto.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an impact energy absorber having excellent impact energy absorption characteristics and a vehicle door trim using the impact energy absorber.

[0002]

2. Description of the Related Art Recently, as a part of improving the safety of vehicles such as automobiles, there has been a problem in dealing with a side collision accident. For example, the inside of a door trim panel or a bulging portion absorbs a shock at the time of collision. The energy absorber that is arranged is disclosed in JP-A-3-28020 and Japanese Utility Model Laid-Open No. 51-
Various proposals have been made as disclosed in Japanese Patent No. 158018. However, all of the conventional energy absorbers of this type are block-shaped rigid polyurethane foam molded articles that absorb energy due to the phenomenon of impact load destruction, and there is the problem that stable characteristics cannot be obtained. In the case of a block-shaped rigid polyurethane foam molded article, when a load exceeding the elastic limit is applied, the block molded article is destroyed by absorbing an impact load and cannot be used repeatedly, resulting in a high cost.

Therefore, the present inventor has developed an impact energy absorber using a block-shaped absorber body made of an elastic material in which a plurality of overhanging plate portions are radially extended around the impact direction as a central axis. Although previously proposed as Japanese Patent Application No. 5-254093, the former invention exhibits higher impact absorption characteristics than the conventional one, but the impact load speed becomes large as shown in FIG. 8 (for example, 1 m / sec or more), it has been found that there is a phenomenon that cracks occur in the overhanging plate portion, a load drop occurs, and energy absorption efficiency decreases.

[0004]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned conventional problems, and elastically distorts and can absorb shock stably while the shock load is small, and the load exceeds the elastic limit. Even if a load is applied, sufficient absorption characteristics can be exhibited without causing a fracture phenomenon, and shocks can be stably absorbed, and load energy is efficiently generated without cracking even when the shock load speed is high. The present invention has been completed for the purpose of providing an impact energy absorber that can be well absorbed and can be repeatedly used to reduce the cost, and an automobile door trim using the impact energy absorber.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems. According to the present invention, a plurality of projecting plate portions having a distal end portion having a wall thickness larger than that of a central portion are radially stretched around the impact direction as a central axis. A shock energy absorber having a front surface of a block-shaped absorber body made of a molded elastic material as a mounting surface for a mounting member and a rear surface as a receiving surface is defined as a first invention. Is a door trim for an automobile mounted on the inner surface of a door interior trim substrate with the mounting surface as a second invention, and the impact energy absorbing ridge portion of the same kind as the impact energy absorber as described above is an inner surface of the door interior trim substrate. A third aspect of the present invention is an automobile door trim that is integrally molded.

[0006]

According to the first aspect of the present invention, the impact energy absorber can be mounted on the inner surface of the door interior trim substrate, the door outer plate or the container side plate with the front mounting surface even if a side collision accident occurs. While the value is small, the block-shaped absorber body made of an elastic material elastically distorts and absorbs the shock stably, and when a load exceeding the elastic limit is applied, the shock absorber becomes radially with the shock direction as the central axis. Since all the bulged plate parts that are bulged will bend in a certain direction and receive the load, it will absorb the shock energy stably without causing damage, and a shock load with a higher speed was applied. Even in such a case, since the tip portion is formed with a large thickness, the load can be sufficiently absorbed and the occurrence of cracks can be prevented. Further, in the automobile door trim according to the second and third aspects of the present invention, the impact energy is stably absorbed by the impact energy absorber and the impact energy absorbing ridge on the inner surface in the same manner as above when a side impact accident occurs.
For the same reason as described above in the first aspect of the invention, the safety of the occupant in the event of a side collision can be ensured.

[0007]

The present invention will now be described in detail with reference to the illustrated embodiments. FIG. 1 shows a first embodiment of the impact energy absorber of the first invention, and 1 is an absorber body made of an elastic body such as thermoplastic foam resin. The absorber main body 1 is formed by four bulging plate portions 2 having a distal end portion having a wall thickness larger than that of the central portion and radially and uniformly bulging around the impact direction as a central axis. In the embodiment shown in FIG. 1, the tip end portion is formed as a uniform taper surface so that the wall thickness becomes gradually larger than the central portion. However, as shown in FIG. It is also possible to form a bulge portion in the bending direction of No. 4, and the number of the projecting plate portions 2 is four as in the embodiment and three as shown in FIG. For example, the number of sheets can be arbitrarily selected within the range of about 3 to 12. The absorber body 1 has a front surface formed on a mounting surface 1a corresponding to the shape of the mounting surface of the door interior trim substrate, which is a mounting member, while the rear surface is a block surface having a receiving surface 1b. There is. In addition, the absorbent body 1 in this example is made of a thermoplastic resin such as polypropylene resin or polyphenylene oxide-modified polystyrene resin in order to achieve sufficient weight reduction and sufficient load-strain characteristics. It is foam-molded from synthetic resin primary foam beads.

As described above, according to the first aspect of the present invention, the absorbent body 1 is formed by elastically forming a plurality of bulging plate portions 2 in which the thickness of the tip portion is larger than that of the central portion in a radial manner with the impact direction as the central axis. There is a characteristic structure that it is molded with a material, and this overhanging plate part 2 exhibits a stable impact absorbing property without breaking or cracking when a load exceeding the elastic limit is applied. To do. That is, as shown in FIG. 4, when a load exceeding the elastic limit is applied in the vertical direction in the drawing, if buckling of a certain overhanging plate portion 2 causes a bow-like deformation, the other overhanging plate portions 2 are also successively deformed. Buckling deformation occurs in a bow in the same direction, and in this deformed state, a constant constant load −
The shock energy is sufficiently absorbed without exhibiting strain characteristics and causing damage or the like. In addition, even when a high-speed impact load is applied, the wall thickness of the tip is formed to be large, so the load can be sufficiently absorbed, cracking can be prevented, and load energy can be absorbed efficiently. It will be. The block-shaped absorber body 1 made of an elastic material may be a thermosetting synthetic resin foam such as rubber or polyurethane resin foam, but when it is a thermoplastic synthetic resin foam as described above, This is particularly preferable in terms of constant load-strain characteristics, durability and cost. Needless to say, the impact energy absorber according to the first aspect of the present invention can be applied to any article that may cause a side collision accident, such as a shipping container, other than an automobile door trim.

Next, a vehicle door trim using the impact energy absorber as the second invention will be explained based on the embodiment shown in FIG. In FIG. 5, reference numeral 10 denotes a door interior trim substrate formed in a three-dimensional shape by forming a bulging portion 11 that bulges with respect to the reference surface 10a with an arbitrary material. Inside, the impact energy absorber is mounted with the mounting surface 1a such that the receiving surface 1b of the block-shaped absorber body 1 is substantially flush with the reference surface 10a. In such an automobile door trim, the impact energy absorber stably absorbs impact energy when external pressure is applied to the bulging portion 11, and therefore the same reason as described in the first invention is provided. This ensures the safety of passengers in the event of a side collision.

In the second aspect of the invention, the door interior trim substrate 10 may be made of any material as described above, but as shown in FIG. A plurality of bulging portions 21 for absorbing impact energy are formed integrally with the inner surface of the door interior trim substrate main body 20 and are made of an elastic material in which a plurality of plate portions 22 radially extend around the impact direction as a central axis. The third aspect of the invention is to use the end surface 21 of the end surface 21b as the receiving surface 21b. In this way, if the raised portion main body 21 for absorbing impact energy is integrally formed on the inner surface of the door interior trim substrate main body 20, the manufacturing process is improved. There is an advantage that it can be simplified. In this case, the bump energy absorbing main body 21 for absorbing the impact energy is generally formed of a thermoplastic synthetic resin such as polypropylene resin or polyphenylene oxide modified polystyrene resin, which is the same material as the door interior trim substrate main body 20, but is multicolored. The bump body 21 for absorbing impact energy may be molded by a molding method or the like so as to have a higher elasticity than the door interior trim substrate body 20. Further, the above-mentioned example of use of the impact energy absorber is only when it is attached to the door interior trim substrate 10 of the automobile door trim having the bulging portion 11, but the impact energy is not applied to the inner surface of the door interior trim substrate having no bulging portion. The absorber may be attached in a protruding state.

In any case, according to the present invention, a plurality of projecting plate portions having a front end portion having a wall thickness larger than that of the central portion are radially arranged around the impact direction at a predetermined position of the door trim so as to absorb impact energy at the time of collision. Even if a side collision accident occurs and the impact is transmitted from the door outer plate to the receiving surface by forming the impact absorbing part made of elastic material bulged on the
While the shock absorbing part made of an elastic material such as thermoplastic foamed resin is elastically distorted and absorbs the shock stably while the shock load is small, even if a load exceeding the elastic limit is applied, the shock Since a plurality of bulging plate parts are radially bulged around the direction of the central axis, these bulging plate parts will bend in a certain direction and receive a load, and shock is stably absorbed without causing damage. Will be done. Further, even when a high-speed impact load is applied, since the wall thickness of the tip portion is formed to be large, the load can be sufficiently absorbed, cracking can be prevented and load energy absorption can be reduced. It can be done efficiently without any effort.

(Experimental example) Next, an experimental result using the impact energy absorber of the first invention will be shown. Using polypropylene bead-shaped material as the thermoplastic foaming synthetic resin as the main material, the overhanging plate portion as shown in FIG.
The absorber main body was formed into a sheet, and the load-strain characteristic was measured at a load speed of 5 m / sec according to the compression test of JIS K7220. The result shows that stable energy absorption characteristic is exhibited as shown in FIG. did it. It was also confirmed that no cracks or fractures occurred and the material could be reused despite the high loading speed. 2 and 3
When a similar experiment was performed using the impact energy absorber as shown in Fig. 4, it was slightly inferior to the case of using four overhanging plate parts, but in all cases, the load exceeded the elastic limit. It was confirmed that even in the case of (1), the energy absorption characteristics were fairly stable and that the load was sufficiently absorbed without cracking even when a high-speed impact load was applied. On the other hand, a block-shaped impact energy absorber (Japanese Patent Application No. 5-254093) made of a rigid polyurethane foam composed of a bulging plate portion of uniform thickness, which was previously applied, was attached at the same location and the same test was conducted. The results are shown in Fig. 8, which is superior to the conventional block-shaped rigid polyurethane foam molded product, but cracks occur in the overhanging plate part due to the effect of a large load speed, and the load falls. It was confirmed that excellent characteristics can be obtained simply by making the thickness of the tip portion of the overhanging plate portion larger than that of the center portion.

[0013]

As is apparent from the above description, the present invention elastically distorts and absorbs a shock stably while the impact load is small, and when a load exceeding the elastic limit is applied. Even when the impact load speed is high, load energy can be efficiently absorbed without causing cracks, while exhibiting sufficient absorption characteristics without causing a fracture phenomenon to stably absorb the impact. Further, it can be used repeatedly, and the cost can be reduced. Therefore, the present invention is extremely large in that it contributes to the development of the industry as an impact energy absorber that eliminates the conventional problems and an automobile door trim using the impact energy absorber.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of an impact energy absorber which is a first invention.

FIG. 2 is a perspective view showing another embodiment of the impact energy absorber.

FIG. 3 is a perspective view showing another embodiment of the impact energy absorber.

4 is an explanatory diagram showing a deformed state of buckling of the impact energy absorber shown in FIG. 1. FIG.

FIG. 5 is a perspective view showing an embodiment of a vehicle door trim which is a second invention.

FIG. 6 is a cross-sectional view of essential parts showing an embodiment of a vehicle door trim which is a third invention.

FIG. 7 is a graph showing load-strain characteristics in the example of the first invention.

FIG. 8 is a graph showing load-strain characteristics in a conventional example.

[Explanation of symbols]

 1 Absorber body 1a Mounting surface 1b Receiving surface 2 Overhanging plate part 10 Door interior trim substrate 20 Door interior trim substrate body 21 Impact energy absorbing raised body 21b Receiving surface 22 Overhanging plate part

Claims (3)

[Claims] 1. A block-shaped absorber body (1) made of an elastic material in which a plurality of overhanging plate portions (2) having a tip end portion having a thickness larger than that of the center portion are radially formed around the impact direction as a central axis. 1)
The impact energy absorber characterized in that the front surface of the rear surface is formed as a mounting surface (1a) to the mounted member and the rear surface is formed as a receiving surface (1b). 2. A block-shaped absorber body (1) made of an elastic material in which a plurality of bulging plate portions (2) having a tip portion having a wall thickness larger than that of a central portion are radially bulged around the impact direction as a central axis. 1)
The impact energy absorber that forms the front surface of the mounting surface (1a) to the mounted member and the rear surface as the receiving surface (1b) is the mounting surface (1a) on the inner surface required portion of the door interior trim substrate (10). A door trim for an automobile, characterized by being attached with. 3. A protrusion main body (21) made of an elastic material in which a plurality of bulging plate portions (22) having a wall thickness of a tip portion larger than that of a central portion are radially bulged around the impact direction as a central axis. A vehicle door trim, characterized in that a bump for absorbing impact energy, which is a receiving surface (21b) of an end surface, is formed integrally with an inner surface of a door interior trim substrate body (20).