JP7614138B2 - Shock absorbing materials - Google Patents

Description

The present invention relates to an impact absorbing member.

Vehicles and the like are equipped with shock absorbing members for absorbing impact energy during a collision. One such shock absorbing member is known to have a cylindrical body with a polygonal cross section. The cylindrical body has a closed space inside, which is created by bending a metal plate in multiple places and welding the edges together. The shock absorbing member is mounted on the vehicle so that the input direction of the impact is the direction that the center line of the cylinder extends. When a collision impact is applied to the cylindrical body of the shock absorbing member, the cylinder buckles, and the impact energy of the collision is absorbed by the shock absorbing member.

Patent Document 1 also describes providing reinforcing parts on multiple ridgelines of a polygonal cylinder. The reinforcing parts are provided on the multiple ridgelines of the cylinder so as to extend along those ridgelines. By providing reinforcing parts on the cylinder in this way, the metal plate forming the cylinder can be made thinner, reducing material costs, while also suppressing the associated decrease in impact energy that can be absorbed during a collision.

International Publication No. 2012/036262

In a cylinder provided with the reinforcing parts, the reinforcing parts and the welded parts are concentrated around the points where the edges of the metal plates are welded together. As a result, the rigidity is high around the points where the edges of the metal plates in the cylinder are welded together, so when the cylinder is subjected to the impact of a collision, large buckling occurs suddenly around the points where the edges of the metal plates in the cylinder are welded together. This reduces the impact energy that can be absorbed by the impact absorbing member.

The shock absorbing member that solves the above problem includes a cylinder with a polygonal cross section. The cylinder has a closed space inside, which is created by bending a metal plate at multiple locations and welding the edges together. Reinforcement sections that extend along multiple ridgelines of the cylinder are provided. When an impact is applied in the direction along the center line of the cylinder, the shock absorbing member absorbs the impact energy by causing the cylinder to buckle. The ridgelines located next to the locations where the edges of the metal plates in the cylinder are joined are unreinforced sections that lack the above-mentioned reinforcement sections.

4 is a schematic diagram showing a cross section of a cylindrical body in the impact absorbing member. FIG. 2 is a perspective view showing the impact absorbing member. FIG. 2 is a perspective view showing the cylindrical body. 4 is a graph showing the relationship between the amount of deformation of a shock absorbing member during a vehicle collision, the magnitude of a force acting on the shock absorbing member, and the collision energy absorbed by the shock absorbing member. FIG. 2 is a perspective view showing the impact absorbing member at the time of a vehicle collision. FIG. 2 is a perspective view showing the impact absorbing member at the time of a vehicle collision. 11 is a schematic diagram showing another example of a cross section of a cylindrical body in the impact absorbing member. 11 is a schematic diagram showing another example of a cross section of a cylindrical body in the impact absorbing member.

Hereinafter, one embodiment of the impact absorbing member will be described with reference to FIGS.
FIG. 1 shows a cross section of a cylindrical body 11 in the impact absorbing member, FIG. 2 shows the impact absorbing member as viewed obliquely from above, and FIG. 3 shows the cylindrical body 11 as viewed obliquely from above.

This shock absorbing member is mounted on a vehicle and absorbs impact energy during a vehicle collision. The shock absorbing member has a metallic cylindrical body 11 with a polygonal cross section. The shock absorbing member is mounted on a vehicle so that the center line of the cylindrical body 11 extends in the longitudinal direction of the vehicle. Metal plates 12 are welded to both ends of the cylindrical body 11 in the direction in which the center line extends.

When the shock absorbing member is mounted on a vehicle, the shock during a vehicle collision is input to the shock absorbing member as shown by the arrow in Figure 2. Therefore, during a vehicle collision, the shock is applied in the direction along the center line of the cylindrical body 11. When a shock is applied in this way in the direction along the center line of the cylindrical body 11, the shock absorbing member absorbs the collision energy by buckling the cylindrical body 11.

<Cylinder body 11>
As shown in Fig. 1 and Fig. 3, the cylindrical body 11 is formed by two metal plates 13. More specifically, the two metal plates 13 are each folded at a plurality of locations, and the edges of the metal plates 13 are overlapped in the thickness direction. The edges of the two metal plates 13 are then welded together to form the cylindrical body 11 having a closed space inside. The edges of the two metal plates 13 may be welded together by laser cladding, for example. The cylindrical body 11 in this example is folded at 16 locations, and has a plurality of ridges (16 in this example). The cross section of the cylindrical body 11 has a shape of a regular octagon connected together. The distances between the plurality of ridges in the cylindrical body 11 are equal.

Reinforcement sections 14 are provided on the multiple ridgelines of the cylindrical body 11 and extend along the ridgelines. The reinforcement sections 14 are formed by laser cladding. As shown in FIG. 3, the reinforcement sections 14 corresponding to each of the multiple ridgelines are made shorter than the length of the ridgelines, thereby exposing the ridgelines on the impact input side of the cylindrical body 11, i.e., the upper end side of FIG. 3. As shown in FIG. 1, the ridgelines located next to the points where the edges of the metal plates 13 of the cylindrical body 11 are joined are unreinforced sections 15 without reinforcing sections 14. The unreinforced sections 15 are located on both sides of the ridgelines located on both sides of the points where the edges of the metal plates 13 of the cylindrical body 11 are joined.

Next, the operation of the impact absorbing member of this embodiment will be described.
Fig. 4 shows the relationship between the deformation amount of the shock absorbing member during a vehicle collision, the magnitude of the force acting on the shock absorbing member, and the collision energy absorbed by the shock absorbing member. The horizontal axis of Fig. 4 represents the deformation amount of the shock absorbing member during a vehicle collision. In Fig. 4, the dashed line LA1 and the solid line LB1 represent the magnitude of the force acting on the shock absorbing member during a vehicle collision, and the dashed lines LA2 and LB2 represent the impact energy absorbed by the shock absorbing member during a vehicle collision.

If reinforcing parts 14 were provided on all ridges of the cylindrical body 11, the reinforcing parts 14 and the welded parts would be concentrated around the points where the edges of the metal plates 13 were welded together. As a result, the rigidity would be high around the points where the edges of the metal plates 13 in the cylindrical body 11 were welded together, so that when the cylindrical body 11 is subjected to an impact during a vehicle collision, as shown in Figure 5, a sudden large buckling would occur around the points where the edges of the metal plates 13 in the cylindrical body 11 were welded together. This reduces the impact energy that can be absorbed by the impact absorbing member.

In this case, the magnitude of the force acting on the impact absorbing member during a vehicle collision changes as shown by the dashed line LA1 in FIG. 4. Also, the impact energy absorbed by the impact absorbing member during a vehicle collision changes as shown by the dashed line LA2 in FIG. 4.

On the other hand, in the impact absorbing member of this embodiment, the ridge line located next to the portion where the edges of the metal plate 13 in the cylindrical body 11 are joined is an unreinforced portion 15 without a reinforcing portion 14. This unreinforced portion 15 prevents the reinforcing portion 14 and the welded portion from being densely packed around the portion where the edges of the metal plate 13 are welded. This density prevents the rigidity of the cylindrical body 11 from increasing. As a result, when the impact of a vehicle collision is applied to the cylindrical body 11, as shown in FIG. 5, a sudden large buckling does not occur around the portion where the edges of the metal plate 13 in the cylindrical body 11 are welded. In other words, in the cylindrical body 11, as shown in FIG. 6, small buckling gradually occurs at multiple points. Through such buckling, the impact absorbing member can effectively absorb impact energy, and the impact energy that can be absorbed by the impact absorbing member can be prevented from decreasing.

In this case, the magnitude of the force acting on the impact absorbing member during a vehicle collision transitions as shown by the solid line LB1 in FIG. 4. Also, the impact energy absorbed by the impact absorbing member during a vehicle collision transitions as shown by the dashed line LB2 in FIG. 4. As can be seen from a comparison of the dashed lines LA2 and LB2 in FIG. 4, by providing the above-mentioned unreinforced portion 15 on the cylindrical body 11 of the impact absorbing member, the impact energy during a vehicle collision can be effectively absorbed by the impact absorbing member.

According to the present embodiment described above in detail, the following effects can be obtained.
(1) It is possible to prevent a decrease in the impact energy that can be absorbed by the impact absorbing member during a vehicle collision.

(2) Because the distances between the multiple ridges in the cylindrical body 11 are equal, when an impact is applied in the direction along the center line of the cylindrical body 11, the cylindrical body 11 buckles evenly around the center line. Therefore, when an impact is applied during a vehicle collision, the cylindrical body 11 can buckle stably. As a result, the impact energy can be efficiently absorbed by the impact absorbing member.

(3) The non-reinforced portions 15 are located on the ridges on both sides of the portion where the edges of the metal plates 13 in the tube 11 are welded together. This more effectively prevents the reinforced portions 14 and the welded portions from becoming crowded around the portion where the edges of the metal plates 13 are welded together.

(4) The reinforcing portions 14 corresponding to each of the multiple ridgelines are made shorter than the length of the ridgelines, thereby exposing the ridgelines on the impact input side of the cylindrical body 11. For this reason, when a collision impact is applied in the direction along which the center line of the cylindrical body 11 extends, buckling is more likely to occur on the impact input side of the cylindrical body 11. As a result, when a collision impact is applied, the cylindrical body 11 can be easily caused to buckle gradually from the impact input side. This allows the cylindrical body 11 to buckle stably.

If the reinforcing portion 14 is made the same length as the ridgeline so that the entire ridgeline is covered by the reinforcing portion 14, the force acting on the impact absorbing member increases suddenly at the beginning of the vehicle collision, as shown by the two-dot chain line LC in Figure 4. However, by making the reinforcing portion 14 shorter than the length of the ridgeline and exposing the ridgeline on the impact input side of the cylindrical body 11, the force acting on the impact absorbing member at the beginning of the vehicle collision is suppressed from increasing suddenly, as shown by the solid line LB1 in Figure 4. This allows the cylindrical body 11 to buckle stably, as described above.

(5) The welding of the edges of the metal plates 13 in the cylindrical body 11 and the formation of the reinforcing portions 14 on the ridges are both performed by laser cladding. This allows the formation of the cylindrical body 11 and the formation of the reinforcing portions 14 to be performed using the same processing machine, which prevents the procedure for manufacturing the impact absorbing member from becoming complicated as would occur if these were performed using separate processing machines.

The above embodiment can be modified, for example, as follows: The above embodiment and the following modified examples can be combined with each other to the extent that no technical contradiction occurs.
The cylindrical body 11 may have a cross section as shown in FIGS.

Only one of forming the reinforcing portion 14 and welding the edges of the metal plate 13 may be performed by laser cladding.
Both the formation of the reinforcing portion 14 and the welding of the edges of the metal plate 13 may be performed by a method other than laser cladding.

The unreinforced portion 15 may be located only on one of the ridgelines adjacent to the portion where the edges of the metal plates 13 in the cylindrical body 11 are joined.
The distances between the multiple ridges of the cylindrical body 11 do not necessarily have to be equal.

The length of the reinforcing portion 14 may be the same as the length of the ridge line of the cylindrical body 11 .
The shock absorbing member may be used for things other than vehicles.
Next, the technical concept that can be understood from the above embodiment will be described.

(A)
A cylindrical body having a polygonal cross section is provided,
The cylindrical body has a closed space inside, the closed space being formed by bending a metal plate at multiple points and welding the edges together,
Reinforcing portions are provided on a plurality of ridgelines of the cylindrical body and extend along the ridgelines,
A shock absorbing member that absorbs collision energy by buckling a cylindrical body when an impact is applied in a direction extending along a center line of the cylindrical body,
An impact absorbing member in which the ridge line located next to the point where the edges of the metal plates in the cylindrical body are joined is an unreinforced portion that does not have the reinforcing portion.

(B)
In the impact absorbing member described above in (A),
The distances between the multiple ridges of the cylindrical body are equal.

(C)
In the impact absorbing member according to the above (A) or (B),
The non-reinforced portions are shock absorbing members located on both ridges adjacent to a point where the edges of the metal plates in the cylindrical body are joined.

(D)
In the impact absorbing member described above in (C),
The reinforcing portions corresponding to the respective ridgelines are shorter than the length of the ridgelines, thereby exposing the ridgelines on the impact input side of the cylindrical body.

(E)
In the impact absorbing member according to any one of the above (A) to (D),
An impact absorbing member in which the edges of the metal plates in the cylindrical body are welded together, and the reinforcing portion is formed on the ridge line by laser cladding.

Reference Signs List 11: Cylinder 12: Plate 13: Metal plate 14: Reinforced portion 15: Non-reinforced portion

Claims (5)

A cylindrical body having a polygonal cross section is provided,
The cylindrical body has a closed space inside, the closed space being formed by bending a metal plate at multiple points and welding the edges together,
Reinforcing portions are provided on a plurality of ridgelines of the cylindrical body and extend along the ridgelines,
A shock absorbing member that absorbs collision energy by buckling a cylindrical body when an impact is applied in a direction extending along a center line of the cylindrical body,
a non-reinforced portion having no reinforcing portion on the ridge line located adjacent to a portion where the edges of the metal plates in the cylindrical body are joined ,
An impact absorbing member in which the edges of the metal plates in the cylindrical body are welded together, and the reinforcing portion is formed on the ridge line by laser cladding . The shock absorbing member according to claim 1, wherein the distances between the multiple ridges in the cylindrical body are equal. The shock absorbing member according to claim 2, wherein the non-reinforced portions are located on the ridges on both sides of the portion where the edges of the metal plates in the cylindrical body are joined. The shock absorbing member according to claim 3, wherein the reinforcing parts corresponding to each of the multiple ridgelines are shorter than the length of the ridgelines, thereby exposing the ridgelines on the impact input side of the cylindrical body. A cylindrical body having a polygonal cross section is provided,
The cylindrical body includes two metal plates bent at predetermined locations, and the edges of the two metal plates are welded together to form a closed space therein and a plurality of ridges that are equidistant from each other;
Reinforcing portions are provided on a plurality of ridgelines of the cylindrical body and extend along the ridgelines,
A shock absorbing member that absorbs collision energy by buckling a cylindrical body when an impact is applied in a direction extending along a center line of the cylindrical body,
a non-reinforced portion having no reinforcing portion on the ridge line located adjacent to a portion where the edges of the metal plates in the cylindrical body are joined ,
The non-reinforced portions are shock absorbing members located on both ridges adjacent to a point where the edges of the metal plates in the cylindrical body are joined .

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