JP2003200854A - Structure with rib - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a structure with ribs having high rigidity and excellent energy absorption performance when a vehicle collides. <P>SOLUTION: This structure 1 has a rectangular or substantially rectangular cross section. A plurality of ribs in two layers erected substantially in parallel with an input direction of energy and composed of a low rib 111 and a high rib 112 which is relatively high for the low rib are provided on an inner side of the cross section. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ribbed structure such as a pillar, a sill, a bumper, a subframe, and a door beam, which can be used as a structure of a vehicle. An excellent ribbed structure.

[0002]

2. Description of the Related Art In order to reduce the weight of automobiles, it has been attempted to use light alloys such as aluminum for body members and chassis members. In addition to the vehicle body and chassis, light alloys are used in engines and transmissions, for example.

Since this type of light alloy has a lower Young's modulus than steel or casting, measures are taken from the aspect of shape in order to cover it and increase the rigidity as a member. Regarding the rib structure, various shapes have been proposed from the viewpoint of increasing the rigidity.

[0004]

However, it is needless to say that the vehicle body member and the chassis member are required to have high rigidity, but they are largely deformed at the time of collision,
It is required to absorb more energy.
From this point of view, the conventional structure has significantly improved rigidity, but when large deformation is required,
Large stress concentration occurs at the rib roots and rib intersections,
There was a problem that it broke early and did not absorb enough energy.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a ribbed structure having high rigidity and excellent energy absorbing performance at the time of collision.

According to the present invention, there is provided a structure having a rectangular or substantially rectangular cross section, the rib being erected inside the cross section substantially parallel to the energy input direction and having a low height. A ribbed structure is provided in which a plurality of two-layer ribs including a rib having a relatively high height with respect to a low rib is provided.

In the ribbed structure of the present invention, since the low ribs are provided, the surface rigidity of the rib installation surface is increased, and the amount of deformation of the structure when a minute load is input to this rib installation surface is small. Becomes This results in a highly rigid structure.

On the other hand, when a large load is applied to the rib installation surface of the structure, such as at the time of a collision, the rib installation surface has a high surface rigidity due to the low ribs, so that the structure is not easily bent and the impact load is applied to the structure. Tell the side wall. This allows
Energy can be absorbed by buckling the side wall surface without bending the collision surface (rib installation surface). When the buckling further progresses, the tips of the high ribs come into contact with the facing surface of the rib installation surface, and the high ribs are plastically deformed, whereby a larger collision energy can be absorbed.

[0009]

According to the present invention, since low ribs are provided, the surface rigidity of the rib installation surface is increased, and the rigidity of the structure with respect to a minute load is increased. Also, for a large load, a rib mounting surface (load input surface) can be provided by providing a low rib.
Does not bend, but the buckling of the side wall surface and the plastic deformation due to the high ribs coming into contact with the facing surface also improve the energy absorption performance against a large load.

Therefore, a preferable structure can be provided by applying it to a site where both high rigidity and high energy absorption are required.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. 1 is an exploded perspective view showing a first embodiment of a ribbed structure of the present invention, FIG. 2 is a view taken in the direction of arrow A in FIG. 1,
FIG. 3 is a sectional view taken along the line III-III in FIG.

As shown in FIG. 1, the ribbed structure 1 of this embodiment has a ribbed structure body 11 and a closure panel 112.
Is a long product having a rectangular cross section. Of these, the ribbed structure 11 has a U-shaped cross section, and has a ceiling surface 114, two side wall surfaces 115 and 115, and two flange surfaces 113 and 113. A plurality of ribs are provided in parallel with the longitudinal direction of the structure 1 on the back surface of the ceiling surface 114, that is, in the bag structure. Rib 1 in FIGS. 2 and 3.
The details of 11, 112 are shown.

The rib of this embodiment is a two-layer structure including a rib 111 vertically standing upright from the back surface of the ceiling surface 114 and a rib 112 standing upright from the back surface of the ceiling surface 114 and having a high height. Composed of ribs. As shown in the figure, two high ribs 112 are provided on the back surface of the ceiling surface 114 at substantially equal intervals, while one low rib 111 is provided between the side wall surface 115 and the high rib 112. , High rib 112,
Two lower ribs 111 are provided between 112.

The distance between the four low ribs 111 provided and the distance between the low ribs 111 and the side wall surface 115 are shown in FIG.
1 to w5, the intervals w1 to w5 are preferably in the range of 10% to 33% with respect to the width W0 of the ceiling surface 114. If installed at intervals of more than 33%, the rigidity of the ceiling surface 114 will not be sufficiently high. Also, 10%
When the low ribs 111 are installed at intervals of less than, the rigidity increases, but the weight of the structure 1 increases, and the increase in rigidity with respect to the increase in weight decreases.

The height of the four low ribs 111 provided is indicated by HL in FIG. 3. The height HL of the low ribs 111 is 2 with respect to the height H0 of the ribbed structure body 11.
It is desirable to be in the range of up to 5 mm. If installed at a height of less than 2 mm, the rigidity of the ceiling surface 114 will not be sufficiently high. Further, when the structure 1 is installed at a height of more than 5 mm, the rigidity is increased, but the weight of the structure 1 is increased, and the increase in rigidity with respect to the increase in weight is decreased.

In this example, the low ribs 111 are provided on the ceiling surface 1.
Four pieces were provided on the back surface of 14 in parallel with the longitudinal direction of the structure 1, but the number of pieces to be provided is not limited at all. Further, the low ribs 111 are not limited to being provided only in parallel to the longitudinal direction of the structure 1, and in addition to the parallel directions, low ribs in the direction perpendicular to the longitudinal direction are added to form a lattice-shaped low rib. Also good. Further, in this example, all the four low ribs 111 are set to have the same height HL.
The identity of L is not limited at all and may be different heights.

The height HH of the high rib 112 of this example is 50% to 100 with respect to the height H0 of the ribbed structure body 11.
It is desirable to be in the range of%. When the height is set to less than 50%, the energy absorbing effect of the high ribs 112 becomes small, and the energy absorbing ability of the structure 1 as a whole becomes insufficient. In the example shown in FIG. 3, the height HH
Is approximately equal to the height H0 of the ribbed structure body 11,
That is, it is set to 100%. In this example, the heights HH of the two high ribs 112 are the same, but the heights HH of the high ribs 112 may be different. Further, the number of the high ribs 112 is not limited to two, and 1
The number of books may be three or more.

Although not particularly limited, the ribbed structure body 11 is manufactured by a casting method or a die casting method of an aluminum alloy or a magnesium alloy. In particular, in the case of manufacturing by a casting method or a die casting method, since the low ribs 111 are arranged at appropriate intervals, the flow of molten metal is good, and thin and large castings can be cast easily and with high quality. There is also.

The closure panel 12 of this embodiment closes the opening of the ribbed structure body 11 and has a rectangular cross section.
It is made of a material such as JIS A6951-T6, and is joined to the ribbed structure body 11 at the flange surface 113 using a rivet or the like.

FIG. 4 is an exploded perspective view showing a second embodiment of the ribbed structure of the present invention, FIG. 5 is a view taken in the direction of arrow A in FIG. 4, and FIG. 6 is a sectional view taken along line VI-VI in FIG. is there.

This example has the same structure as that of the above-described first embodiment except that the height HH of the high rib 112 is approximately half (50%) of the height H0 of the ribbed structure body 11. . The same members are designated by the same reference numerals, and detailed description thereof will be omitted.

The ribbed structure 1 according to the first embodiment and the second embodiment is not particularly limited. For example, the chassis of an automobile, the pillars P1, P2, P3, and the sill S of the automobile body B shown in FIG. , A bumper (not shown), a sub-frame (not shown), a door beam (not shown), or the like.

Next, referring to FIG. 14 and FIG.
The operation of the above-described first and second embodiments of the present invention will be described. Here, the ribbed structure 1 of the second embodiment will be described as an example.

When a slight load is applied to the ceiling surface 114 of the ribbed structure 1 of the present example, the presence of the four low ribs 111 provided on the back surface of the ceiling surface 114 causes the ceiling surface 1 to move.
Since the surface rigidity of 14 is high, the deformation amount of the ribbed structure 1 is extremely small.

On the other hand, as shown in FIG. 14, the ceiling surface 114
When a large load is applied to the ceiling surface 114 (see the arrow in the figure), the rigidity of the ceiling surface 114 is increased due to the presence of the four low ribs 111, so that the ceiling surface 114 is increased.
Does not bend, and the large load is transmitted to the side wall surfaces 115, 115. When a large load is transmitted to the side wall surfaces 115 and 115 on both sides, the side wall surfaces 115 and 115 start buckling without being able to endure, but the buckling of the side wall surfaces 115 and 115 absorbs the energy of the large load. .

When the buckling further progresses, as shown in FIG. 15, the tips of the high ribs 112 come into contact with the facing closure panel 12, and from this point, in addition to the buckling of the side wall surfaces 115, 115, the plasticity of the high ribs 112 increases. Deformation also begins. As a result, the heavy load energy is further absorbed.

[0027]

EXAMPLES Hereinafter, examples in which the present invention is further embodied will be described, but the present invention is not limited to the numerical values in the examples.

Example 1 In the ribbed structure 1 having the structure shown in FIG. 1, the ribbed structure body 11 has a plate thickness of 2 mm and a sectional shape of 65 mm ×
A 65 mm square was used, and the thickness of the closure panel 12 was 1 mm. Thickness of low rib 111 is 2mm, height H
L was 5 mm and the width interval was 8 mm. Also high rib 1
The plate thickness of 12 was 2 mm, and the height HH was 65 mm.

The structure body 11 with ribs is made of Al-11%.
The closure panel 12 was manufactured by using a die-casting method using Si-0.3% Mg alloy, and the closure panel 12 was manufactured by using A6951-T6 material, and these were joined at the flange surface 113 by using pop rivets.

Embodiment 2 In Embodiment 1, the height HH of the high rib 112 is 32.
The conditions were the same as in Example 1 except that the thickness was 5 mm.

Comparative Example 1 As a comparative example of Examples 1 and 2, as shown in FIG. 7, a structure in which low ribs 111 and high ribs 112 are not provided in the ribbed structure 1 of Example 1. 1'was created. The conditions were the same as in Example 1 except that the low ribs 111 and the high ribs 112 were not provided.

Comparative Example 2 As a comparative example of Examples 1 and 2, as shown in FIGS. 8 and 9, instead of the low ribs 111 and the high ribs 112 of Example 1, corrugated ribs 116 are used as the structure body 11. A structure was created under the same conditions as in Example 1 except that the structure was formed. The height of the corrugated ribs 116 was 16.25 mm (1/4 of the height of the structure body 11).

Rigidity test In order to confirm the rigidity of the examples and comparative examples, a static three-point bending tester shown in FIG. 10 was used, the structure was placed on a support jig, and 10 kg of the structure was placed in the center of the structure. The amount of displacement when the load was input was measured. Bending rigidity per unit weight was obtained by calculation based on the measured displacement amount. The result is shown in FIG.
Shown in.

According to these results, the first and second embodiments
Both show higher rigidity than Comparative Example 1 without ribs,
Further, the comparative example 2 in which the corrugated ribs 116 are provided also has high rigidity equal to or higher than that.

Absorbed Energy Amount Test In order to confirm the absorbed energy amount of Examples and Comparative Examples, the falling weight impact bending test apparatus shown in FIG. 11 was used, the structure was placed on a supporting jig, and the center of the structure was placed. On the other hand, the amount of displacement when a striker having a weight of 300 kg was dropped from a height of 3 m was measured. Based on the measured displacement amount, the amount of absorbed energy per unit weight was calculated. The results are shown in FIGS. 13 and 16. The amount of absorbed energy per unit weight in FIG. 13 was a displacement amount up to 100 mm.

According to the results shown in FIG. 13, in both Example 1 and Example 2, the rib-less Comparative Example 1 and the corrugated rib 11 were used.
As compared with Comparative Example 2 in which No. 6 was provided, the amount of absorbed energy was significantly higher. In the example 1 in which the tall ribs 112 have the same height as the structure body 11, the height of the comparative example 1 is 50.
Even in Example 2 in which the rib 112 with a high% and the height of the rib 112 are half the height of the structure body 11, the absorbed energy amount with a 20% increase in Comparative Examples 1 and 2 was confirmed.

Further, according to the results shown in FIG. 16, when comparing the comparative example 2 provided with the corrugated ribs 116 with the examples 1 and 2, the absorbed energy amount at the early stage of deformation in which the striker displacement is small is not so different. It can be understood that the greater the deformation, the larger the difference in absorbed energy, and that Examples 1 and 2 are superior.

The above-described embodiments are described for facilitating the understanding of the present invention, and are not described for limiting the present invention. Therefore, each element disclosed in the above-described embodiment is intended to include all design changes and equivalents within the technical scope of the present invention.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing a first embodiment of a ribbed structure of the present invention.

FIG. 2 is a view on arrow A in FIG.

FIG. 3 is a sectional view taken along the line III-III in FIG.

FIG. 4 is an exploded perspective view showing a second embodiment of the ribbed structure of the present invention.

5 is a view on arrow A in FIG. 4. FIG.

6 is a sectional view taken along line VI-VI of FIG.

7 is an exploded perspective view showing a structure used as Comparative Example 1. FIG.

8 is an exploded perspective view showing a structure used as Comparative Example 2. FIG.

9 is a view on arrow A in FIG.

FIG. 10 is a conceptual diagram showing a static three-point bending test device used in a rigidity test.

FIG. 11 is a conceptual diagram showing a falling weight impact bending test device used in an absorbed energy test.

FIG. 12 is a graph showing the results of a rigidity test.

FIG. 13 is a graph showing the results of an absorbed energy test.

FIG. 14 is a cross-sectional view illustrating the operation of the structure according to the embodiment of the invention.

FIG. 15 is a cross-sectional view illustrating the operation of the structure according to the embodiment of the invention.

FIG. 16 is a graph showing the results of an absorbed energy test.

FIG. 17 is a perspective view of a vehicle body showing an example of a portion to which the structure according to the present invention can be applied.

[Explanation of symbols] 1 ... Ribbed structure 11 ... Ribbed structure body 111 ... Low rib 112 ... high rib 113 ... Flange surface 114 ... Ceiling surface 115 ... Side wall surface 12 ... Closure panel H0 ... height of structure HL ... Low rib height HH ... high rib height W0 ... width of structure W1-W5 ... Low rib width spacing

Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) B62D 25/20 B62D 25/20 F

Claims (11)

[Claims] 1. A structure having a rectangular or substantially rectangular cross section, the rib being erected inside the cross section substantially parallel to the energy input direction and having a low height and a rib having a low height. The ribbed structure is provided with a plurality of two-layered ribs including a relatively high rib. 2. The ribbed structure according to claim 1, wherein the rib is provided on a back surface of a surface to which energy is input and perpendicular to the back surface. 3. The ribbed structure according to claim 1, wherein the ribs are provided parallel to a longitudinal direction of the structure. 4. The ribbed structure according to claim 1 or 2, wherein the low ribs are provided in a grid pattern parallel and perpendicular to the longitudinal direction of the structure. 5. The ribbed structure according to claim 1, wherein the height of the low rib is 2 to 5 mm with respect to the sectional height of the structure. 6. The ribbed structure according to claim 1, wherein the height of the high rib is 50% to 100% with respect to the sectional height of the structure. 7. The ribbed structure according to claim 1, wherein an interval between the low ribs in a width direction is 10% to 33% with respect to a width of a surface on which the high rib is provided. . 8. The structure has a first member having a U-shaped cross section and a second member for closing an opening of the first member, the first member being formed by a casting method, and the first member. The ribbed structure according to any one of claims 1 to 7, wherein the rib and the second member are joined together. 9. The ribbed structure according to claim 1, which is made of an aluminum alloy or a magnesium alloy. 10. The ribbed structure according to claim 1, which is a car body part or a chassis part of an automobile. 11. The ribbed structure according to claim 10, which is a pillar, a sill, a bumper, a subframe or a door beam of an automobile.