JPH07205655A - Automobile door reinforcing member and automobile door - Google Patents

Abstract

PURPOSE:To suppress the sectional surface deformation in bending, increase strength, and improve the anti-side surface collision strength, by forming an automobile door reinforcing member to a closed sectional shape of a trapezoid. CONSTITUTION:The sectional shape of an automobile door reinforcing member 1 is formed to a closed section of a trapezoidal shape consisting of a wire ground plate 4, narrow top plate 3, and the outer periphery 3, and in the use as the door reinforcing member 1, the ground plate 4 is arranged on a door inner plate 6 side, and the top plate 3 is arranged on a door outer plate 5 side. Accordingly, in comparison with an extrusion member having the equal max. bending load, the weight can be reduced in comparison with a reinforcing member having a simple square section or round section, and the anti-side surface collision strength can be improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reinforcing material mounted inside a vehicle door for protecting an occupant in the event of a side collision and a vehicle door equipped with the reinforcing material.

[0002]

2. Description of the Related Art In recent years, in the automobile industry, importance is attached to safety against side collisions, and reinforcing materials are attached to doors of almost all vehicles not only for export but also for domestic passenger cars.
Automotive door reinforcements are currently used, for example, in Japanese Patent Laid-Open No. 1-20.
A high-strength electric resistance welded steel pipe as disclosed in Japanese Patent No. 5032 is predominant.

On the other hand, from the viewpoint of environmental problems, the improvement of fuel efficiency of automobiles has been aimed at, and the weight reduction of vehicles has become a major issue. Therefore, it is desired to reduce the weight of the automobile door reinforcing material as much as possible, and the square steel pipe which is more advantageous in the second moment of section than the steel pipe having the round cross section has been adopted.
Recently, not only steel but also aluminum has been attracting attention as a material. Since aluminum is manufactured by extrusion, it has a greater degree of freedom in cross section than electric resistance welded steel pipes, and not only simple square and rectangular cross sections but also reinforcing materials having cross sections as shown in FIG. 6 have been put to practical use. That is, FIG. 6 is a sectional view of a conventional automobile door reinforcing material. 6A shows a regular cross section, FIG. 6B shows a rectangular cross section, and FIG. 6C shows a reinforcing material similar to a square cross section.

[0004]

Currently, automobile door reinforcements are generally evaluated by a bending load-displacement curve drawn by a three-point bending test using a semicircular punch as shown in FIG. FIG. 8 is an explanatory diagram of a cross-sectional deformation state when a three-point bending test is performed on a conventional square tube having a square cross section. The square tube not only has a higher second moment of area than the round tube, but also
Since the side plate 2 is parallel to the load applying direction as shown in (a), the force was not dispersed and the side plate 2 was effectively loaded with the force, which was expected to be very strong against flatness. However, as the bending actually progresses, the width of the base plate 4 corresponding to the outside of the bending becomes narrower than that of the top plate 3 corresponding to the inside of the bending as the length in the pipe axis direction becomes longer. Therefore, immediately before the tube buckles, as shown in FIG. 8 (b), the top plate 3 is wide,
The base plate 4 has a narrow trapezoidal shape. Then, since the load direction and the side plate 2 are not parallel, the force is dispersed,
As a result, there has been a problem that the cross-sectional deformation becomes large or cracks are likely to occur at the corners.

[0005]

In order to solve the above problems, there is a reinforcing member having a shape advantageous for suppressing the cross-sectional deformation during bending, and an automobile door equipped with the reinforcing member. The gist of the invention is that an automobile door reinforcing material having a trapezoidal closed cross-sectional shape, and a wide surface of the two parallel surfaces of the automobile door reinforcing material of the present invention is the inside of the door. The vehicle door is characterized in that a narrow surface is attached to the plate side and a door outer plate side is attached to the plate side.

[0006]

The function of the present invention will be described in detail below. First, the reason why the cross section of the reinforcing material is trapezoidal will be described. The shape of the punch used for the three-point bending test of the reinforcing material shown in FIG.
Side strength evaluation test of actual vehicle (FMVSS No. 214)
It has the same shape as the punch used in. Therefore, the reinforcing material is shaped so as to be wrapped around 150 mm of the punch unless it is buckled. The strain ε _{TL in} the tube axis direction on the outside of bending at that time is shown in FIG. That is, FIG. 2 is an explanatory view of strain in the tube axis direction during bending deformation. From this figure, since there is a relation of 150 + h / 2: 150 + h = 1: 1 + ε _TL , it is expressed as ε _TL = h / (300 + h). The strain ε _{CL in} the tube axis direction inside the bend is ε _CL = −ε _TL .

When the strain in the width direction is considered to be −ν times (ν: Poisson's ratio) the strain in the pipe axis direction, the strain ε in the width direction inside the bend is considered.
_CB and the lateral strain ε _{TB on the} outside of the bending are expressed as follows. ε _CB = −ε _TB = νh / (300 + h) Here, when the initial cross section is a rectangular cross section with a width b and a height h, the width when wrapped around the punch is b [1+
νh / (300 + h)], b [1-νh /
(300 + h)]. That is, [300+ (1 + ν) h] / [300+ (1-
ν) h] times wider.

Therefore, conversely, the initial cross section is formed into a trapezoidal shape, and the outside of the bend is [300+ (1 + ν) h] / with respect to the inside of the bend.
If the length is [300+ (1-ν) h] times, it becomes a rectangular (or square) shape when wound around the punch, the force is not dispersed, and it is effective in preventing cross-sectional deformation and corner cracking. Become.

FIG. 1 is an explanatory view of an automobile door reinforcing material obtained by the present invention. 1 (a) is a cross-sectional view of the reinforcing material, FIG.
(B) is a figure which shows the state attached to the vehicle door.
That is, in the direction in which the reinforcing material of the present invention is mounted inside the automobile door, the wide surface (base plate) 4 is arranged on the door inner plate 6 side,
It is necessary to arrange the narrow surface (top plate) 3 on the door outer plate 5 side. In addition, reference numeral 1 in FIG.
Is the outer circumference. Further, as described above, it is most effective to accurately specify the length in the structure of the reinforcing material,
By simply making the outer side of the bend wider than the inner side of the bend, the collision strength on the opposite side is improved as compared with a simple rectangle or square.

[0010]

EXAMPLE 150 kg of trapezoidal cross section as shown in FIG.
A three-point bending test shown in FIG. 7 was carried out using a f / mm ² grade square steel pipe. In this cross-sectional shape, as described above, the width of the wide side surface is [300+ (1+
ν) h] / [300+ (1-ν) h] times.
However, the Poisson's ratio ν was 0.5. For comparison, the same cross-sectional area as the trapezoidal cross section and the width of the same material of 32 mm,
A test was also performed on a square cross section (B) having a wall thickness of 2 mm and a round cross section (C) having an outer diameter of 32 mm and a wall thickness of 2.6 mm.

A bending load-displacement curve is shown in FIG. From this figure, it can be seen that the maximum load is remarkably improved in the product (A) of the present invention when compared with the simple square cross section (B) and the round cross section (C). In general, car door reinforcement is empirically 15
Although the absorbed energy up to a displacement of about 0 mm is important, in the reinforcing material of the product (A) of the present invention, the absorbed energy amount up to 150 mm (the area surrounded by the load-displacement curve).
It can be seen that is also larger than the conventional simple square section (B) and round section (C).

In the above embodiment, an example of a simple trapezoidal shape having an equal thickness is shown in FIG. 3, but the material is not an electric resistance welded steel pipe,
In the case of aluminum extruded material, the cross-sectional shape can be determined relatively freely. An example of the cross-sectional shape of the product of the present invention other than FIG. 3 is shown in FIG.
Shown in. FIG. 5 is a view showing an example of a cross-sectional view of the automobile door reinforcing material of the present invention. 5 (a) is a sectional view of a trapezoidal shape having upper and lower walls, FIG. 5 (b) is a sectional view of the same trapezoidal left and right wall thicknesses, and FIG. 5 (c) is a sectional view of a ribbed trapezoidal shape. Figure 5
(D) is a cross-sectional view in which ribs are further provided on the left and right sides of the center of the trapezoid. As shown in this figure, the effect as described above is the same as long as the shape includes a trapezoid in the cross section. However, in the case of a collision from the side of the actual vehicle, the collision height differs depending on the vehicle model of the opponent, so in order to handle collisions of any height, the cross-sectional shape is symmetrical with respect to the axis parallel to the load load direction. It is preferable.

[0013]

In the above embodiments, the extruded materials having the same cross-sectional area (same weight) were compared, but when compared with the extruded materials having the same maximum bending load, the product of the present invention has a conventional simple square cross section or It is possible to reduce the weight compared to a reinforcing material having a circular cross section.

[Brief description of drawings]

FIG. 1 is an explanatory view of an automobile door reinforcing material obtained by the present invention,

FIG. 2 is an explanatory view of strain in a pipe axis direction during bending deformation,

FIG. 3 is a cross-sectional view of a square steel pipe having a trapezoidal cross-section, which is an example of the product of the present invention;

FIG. 4 is a bending load-displacement curve diagram obtained by a three-point bending test.

FIG. 5 is a diagram showing an example of a cross-sectional view of an automobile door reinforcing material of the present invention,

FIG. 6 is a cross-sectional view of a conventional automobile door reinforcing material,

FIG. 7 is an explanatory diagram of a three-point bending test,

FIG. 8 is an explanatory diagram of a cross-sectional deformation state when a three-point bending test is performed on a conventional square-section square tube.

[Explanation of symbols]

 1 Car Door Reinforcement Material 2 Side Plate 3 Top Plate 4 Base Plate 5 Car Door Outer Plate 6 Car Door Inner Plate 7 Support Point 8 Punch

Claims (2)

[Claims] 1. An automobile door reinforcing material having a trapezoidal closed cross-sectional shape. 2. The automobile door reinforcing material according to claim 1, wherein the wider surface is attached to the door inner plate side and the narrower surface is attached to the door outer plate side of the two parallel surfaces. And the car door.