JPH0424118A - Automobile door guard - Google Patents

Abstract

PURPOSE:To improve the extent of anti-buckling strength by heightening the extent of anti-sagging strength in a direction orthogonal with the load acting direction of a beam side wall with a reinforced material, in an automobile door guard which receives lateral load at the side of a bottom plate closing an opening at the bottom surface side of a beam. CONSTITUTION:An automobile door guard 10 being installed in a door in order to increase the strength of anti-lateral load is made up of unifying a bottom plate 16 to the bottom side of a cross-sectional hat type beam 12 by means of welding. In this case, a cross-sectional hat type reinforced material 20 is installed in and around a hat part 13 of the beam 12. In addition, this reinforced material 20 is formed into a size larger than the cross-sectional form of the beam 12, and each eaves part 24 is joined to a beam side eaves part 14 and the bottom plate 16 by means of spot welding. Moreover, a hat part 23 of the reinforced material consists of a central area 23a extending along a ceiling surface 13a of the hat part 13 of the beam, and a side wall 23b extending along a side wall 13b of the hat part of the beam and narrowing toward an end edge from the central area 23a.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a door guard for an automobile, which is disposed inside a door to increase the resistance to lateral loads.

[Prior art]

As a conventional door guard of this type, Japanese Patent Application Laid-Open No. 64-47
There is No. 615. As shown in Fig. 13, this has a structure in which a reinforcing member 4 with a U-shaped cross section is attached to the load acting side of the beam material 2, which has a rectangular cross section, and covers the beam material 2. Compression acts on one side and tension acts on the opposite side, but since the reinforcing material 4 disperses these forces, the beam material does not break and the entire beam deforms to absorb the impact. Curve C in FIG. 12 is a load-displacement characteristic curve of a conventional door guard, and symbol C indicates the maximum load point.

[Problem to be solved by the invention]

However, with the conventional door guard described above, deformation of the beam cannot be sufficiently suppressed after the maximum load point C.

That is, when the beam material buckles, as shown by the imaginary line in FIG. Although the entire beam material buckles, since the double-shaped opening side end portions 4a of the reinforcing member 4 are attached to the side wall 2a of the beam independently from each other, this is sufficient to suppress the deflection of the side wall 2a of the beam material. It is not working.

The present invention has been made in view of the problems of the prior art,
The purpose is to provide a high-strength automobile door guard that has increased buckling strength by increasing the deflection strength in a direction perpendicular to the direction of load application on the beam side wall using a reinforcing material.

[Means to solve the problem]

In order to achieve the above object, in the automobile guard bar according to the present invention, a bottom plate that closes the opening on the bottom side of the beam material is welded and integrated with the eave part of the cross-sectional hat-shaped beam material. A door guard for an automobile that receives a lateral load, wherein a cross-section hat-shaped reinforcing member is provided, the eave part of which is welded to the eave part of the beam material to cover the hat part of the beam material,
A ceiling wall extending along the ceiling wall of the hat portion of the beam material is formed approximately at the center in the longitudinal direction of the reinforcing material, and a side wall of the reinforcing material extending along the side wall of the hat portion of the beam material is formed at the end. It is designed to have a shape that is sandwiched in the middle (including shapes in which the width gradually changes stepwise, such as a tapered shape and an arc shape).

[Effect]

The top plate is connected to the center of the reinforcing material, which has a sufficient effect of suppressing the deflection of the side walls. In addition, in the area other than the center of the beam material, there is no top plate and only the side walls are left, but since the cross-sectional area of the side walls gradually decreases toward the ends, the entire span of the beam material receives a lateral load and bends under the load. receive. Therefore, when measuring the load-displacement characteristics, the amount of energy absorbed increases by several percent (when the product has the same weight as the conventional example).

〔Example〕

Next, embodiments of the present invention will be described based on the drawings.

Figures 1 to 7 show an embodiment of the door guard according to the present invention. Figure 1 is a perspective view of the door guard, Figure 2 is a perspective view of a reinforcing member, and Figure 3 is a developed view of the reinforcing member. , Figures 4 and 5 are cross-sectional views taken along lines IV-IV and V-V shown in Figure 1, Figure 6 is an explanatory diagram explaining the action of the reinforcing material, and Figure 7 is a diagram showing the bending effect on the door guard. It is a moment diagram.

In these figures, reference numeral 10 is a door guard for an automobile, and a bottom plate 1 is attached to the bottom side of a beam member 12 having a hat-shaped cross section.
6 are integrated by welding. A reinforcing member 20 having a hat-shaped cross section is arranged around the hat portion 13 of the beam material. The reinforcing material 20 has a hat shape that is one size larger than the cross-sectional shape of the beam material 12, and the eave portion 24 is spot welded (reference numeral 18) to the beam material side eave portion 14 and the bottom plate 16 in an overlapping state.
(indicates a spot welding point), and as shown in FIG. 4, the reinforcing member's hat 23 covers the beam member's hat 13 with almost no gaps. The reinforcing member hat portion 23 extends along a central region 23a extending along the ceiling surface 13a of the beam material hat portion 13 and along the side wall 13b of the beam material hat portion, and extends from the central region 23a. It is composed of a side wall 23b that is sandwiched in between toward the end edge. That is, FIG. 3 shows a developed view of the reinforcing material 20, and as shown in this figure, the reinforcing material 20 has a substantially trapezoidal region 21 (indicated by diagonal lines) facing from a rectangular plate material. It is formed by cutting it out and bending it at the bending line position indicated by reference numeral 22.

In the door guard 10 having such a structure, when a lateral load as shown by the symbol P in FIG. 6 is applied, the longitudinal distribution diagram of the bending moment acting on the door guard 10 becomes as shown in FIG. Since the moment is equally distributed over the central region 23a of the reinforcing member 20, the bending moment, that is, the bending stress is not concentrated only at the point of load application, and the strength against bending deformation is correspondingly strong. In addition, since the cross-sectional area of the reinforcing material 20 is smaller toward the end when the bending moment acting on it is tJs, the weight of the reinforcing material 20, that is, the total weight of the door guard 10 is small, but the bending strength is as shown in FIG. It has the same strength as a door guard that has a U-shaped structure with a uniform cross section without cutting out the rectangular plate material. In particular, when an impact force that deforms the side wall 13b of the beam material acts, the side wall 13b should be moved outward (arrow P1 in Fig. 6).
However, the side wall region 23b of the reinforcing material extending outside the side wall of the beam material prevents the deformation of the side wall 13b of the beam material and suppresses the deflection of the beam material 12.

Curve A in FIG. 12 shows the load-displacement characteristics of the door guard of this example. As can be seen from this characteristic curve, there is no sudden deformation even after the maximum load shown in the figure is applied, and the entire door guard is approximately uniform. - Curved and deformed to fully demonstrate its function as a door guard. When a conventional example and a product of the present invention were prototyped with the same weight, and their load-displacement characteristics were measured and compared, it was found that the product of the present invention had an increased energy absorption amount of several percent compared to the conventional product. In other words, the door guard is durable and does not have the problem of sudden deformation (buckling) at a certain load point, causing the door guard to bend and endanger the occupants inside the door.

In the above embodiment, the hat portion 23 of the reinforcing member 20 is arranged around the hat portion 13 of the beam member 10 with almost no gap, but as shown in FIG. 8, a gap is formed between the two. It is also possible to arrange the door guard in such a way that it can be freely adjusted in consideration of the strength, weight, volume, etc. of the door guard.

FIG. 9 is a perspective view of a reinforcing member which is a main part of a third embodiment of the present invention. Above mentioned 1. In the second embodiment, the reinforcing member 20 is formed by cutting out a rectangular plate material, and the portion 21 cut out from the plate material is discarded. However, the reinforcing material 3o shown in this embodiment has a structure in which two members 30A and 30B are welded together at the central position, and has the advantage of high material boarding efficiency.

In the two embodiments described above, the cross-sectional shape of the beam member 10 and the central cross-sectional shape of the reinforcing member 20, 30 are respectively described as U-shaped hat shapes.
It may also have an arcuate hat shape as shown in FIG.

FIG. 12 is a diagram showing the load-displacement characteristics of the present invention and the conventional example, where curve A is the characteristic curve of the door guard of the first embodiment, curve 3 is the characteristic curve of the door guard having the cross-sectional shape shown in FIG. A1. Curve B1 shows the characteristic curve of a door guard having a structure corresponding to FIGS. 4 and 10 without reinforcing material, and curve C shows the characteristic curve of a conventional door guard (see FIG. 13).

〔Effect of the invention〕

As is clear from the above description, according to the automobile door guard according to the present invention, since the central top plate of the reinforcing material covering the beam material is joined, the side walls of the beam material tend to bend outward. is strongly suppressed from the top plate side. In addition, since the eaves section has a three-layered structure and is highly rigid, the deflection of each side wall is strongly suppressed from the bottom plate side as well. In this way, the door guard has a structure in which the deflection of the side wall is strongly suppressed at the center and gradually loosened as it approaches the ends.

Therefore, when a vehicle collides and a load is applied to the door guard, the absorbed energy is increased by several percent compared to the conventional example (it can be seen from the load-strain characteristic diagram that the area occupied by the curve is larger), which improves occupant protection. Very effective for its purpose.

In addition, as a manufacturing advantage, when using a square pipe material like the conventional example, arc welding or spot welding can be considered for welding the reinforcing plate, but arc welding has poor productivity, while spot welding requires an intermediate electrode. However, the hat-shaped cross section does not have this problem.

In addition, it is common to use high tensile strength material (tensile strength is 50 kg/kaku2~150 kg/at'') as the material.
Its formability is very poor, so the process of forming a round pipe, drawing it into a square pipe, and then heat-treating it is expensive. On the other hand, according to the present invention, a completed product can be directly obtained by press-working a high-strength material into a hat-shaped cross section and then spot-welding the bottom plate and the reinforcing material, making it possible to significantly reduce costs.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a door guard according to a first embodiment of the present invention;
Fig. 2 is a perspective view of the reinforcing member, Fig. 3 is a developed view of the reinforcing member, and Figs. 4 and 5 are along lines IV-IV and V shown in Fig. 1.
-V is a sectional view along line V, FIG. 6 is an explanatory diagram explaining the action of the reinforcing material, FIG. 7 is a bending moment diagram acting on the door guard, and FIG. 8 is a cross-sectional view of the door guard according to the second embodiment of the present invention. , FIG. 9 is a perspective view of a reinforcing member which is a main part of an embodiment of the present invention, FIGS. 10 and 11 are cross-sectional views of door guards of other embodiments of the present invention, and FIG. 12 is a perspective view of a reinforcing member according to an embodiment of the present invention. Figure 13 showing the load-displacement characteristics of the door guard and the conventional door guard.
The figure is a perspective view of a conventional door guard, and FIG. 14 is an explanatory diagram illustrating how the conventional door guard buckles. DESCRIPTION OF SYMBOLS 10... Door guard, 13... Hat part of beam material, 14... Eave part of beam material, 16... Bottom plate, 2o... Reinforcement material. 23... Heart part of reinforcing material. 23a...Central region which is the ceiling wall of the hat portion of the reinforcing material, 23b...Side wall of the hat portion of the reinforcing material, 24...Eave portion of the reinforcing material.

Claims (1)

[Claims] (1) An automobile door guard in which a bottom plate that closes the opening on the bottom side of the beam material is integrally welded to the eaves part of a hat-shaped beam material in cross section, and the bottom plate receives a lateral load, and the eave part is connected to the beam material. A cross-sectional hat-shaped reinforcing member is welded to the eaves of the beam material and covers the hat portion of the beam material, and a ceiling extending along the ceiling wall of the hat portion of the beam material is provided approximately at the longitudinal center of the reinforcing material. A door guard for an automobile, characterized in that a wall is formed and a side wall of a reinforcing material extending along a side wall of a hat portion of a beam material is shaped to become narrower toward an end.