JP2004042883A - Bumper device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the lateral deformation or break-off of a crush box arranged between a bumper reinforcement and a side member due to a lateral load which is applied at the time of collision. <P>SOLUTION: A pipe body 2 constituting the crush box 1 is formed by deep-drawing of a steel plate. Its cross section is such that the ratio Y/X of a maximum size X of the vehicle in the cross direction to a maximum size Y in the vertical direction is 1.5-2.4. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a bumper device having an improved crash box.
[0002]
[Prior art]
2. Description of the Related Art A bumper device is used to reduce an impact force on an occupant at the time of a vehicle collision. The bumper device arranges a crash box between the bumper reinforce and the side member on the vehicle body side, absorbs the impact energy at the time of collision by plastic deformation between the bumper reinforce and the crash box, Prevents deformation and breakage of side members.
[0003]
One example of the crash box is disclosed in Japanese Patent Application Laid-Open No. 11-173357 or U.S. Pat. In this known example, one end of a pipe material is turned up to form a reversing portion (turning portion), a peripheral edge of the reversing portion is fixed to a member on a side member side of a vehicle body, and a front end opening edge of the pipe material is a member on a bumper reinforce side. It is a configuration of fixing to.
In this example, at the time of collision of the vehicle, the reversing part moves in the axial direction, plastically deforms the main body of the pipe material sequentially, and shortens the length in the axial direction, thereby absorbing the impact energy. .
[0004]
Further, in the example disclosed in Japanese Patent Application Laid-Open No. 2002-356134, the crash box is constituted by a cylindrical body whose diameter gradually decreases from the inner surface of the front wall of the bumper reinforce (bumper beam) toward the side member. ing. In this example, the bottom of the crush box is connected to the inner surface of the front wall of the bumper reinforce, and the rear end of the small diameter is welded to the mounting (lid) plate of the side member.
[0005]
[Patent Document 1]
JP-A-11-173357 [Patent Document 2]
US Pat. No. 6,310,095 [Patent Document 3]
JP, 2002-356134, A
[Problems to be solved by the invention]
In the known example, since only a process of providing a reversal portion using a pipe material having a circular cross section is performed, the configuration is weak in bending strength.
As is known, a vehicle collision applies an impact force to the bumper reinforce from all directions, so that the load applied to the crash box is not limited to only the axial direction. That is, it is often observed that a load obliquely acts on the crash box with respect to the axial direction of the crash box.
In this case, the pipe material constituting the crush box is easily bent between the inverted portion and the front end, and the expected impact energy absorbing effect by plastic deformation cannot be obtained.
[0007]
In the example of JP-A-2002-356134 described above, the front end of the crash box is joined to the inner surface of the front wall of the bumper reinforce, so that the crush box is tall and the small-diameter portion at the base is formed by the side member. Since it is welded to the mounting plate, the swing of the bumper reinforce during running of the vehicle is large, the energy absorption diagram (relation between stroke and load) at the time of vehicle collision becomes stepwise, and the energy loss is large and the vehicle The amount of deformation (stroke) increases.
[0008]
Therefore, an object of the present invention is to solve the above-described disadvantages of the related art.
[0009]
[Means for Solving the Problems]
According to the present invention, in order to solve the above-described problem, the cross-sectional shape of the crash box is such that the ratio of the maximum length X in the width direction of the vehicle to the maximum length Y in the vertical direction, Y / X, is 1.5 to 2 .4 technical means are basically adopted.
The adoption of this means enables the plastic deformation due to the axial component regardless of the direction of the impact force applied to the crash box, and there is no lateral deformation or breakage of the crash box.
[0010]
Preferably, the crush box is formed by deep drawing of a steel plate. Deep drawing of steel sheet imparts work hardening to the crush box, increases lateral bending strength, and shows strong resistance to impact force from oblique directions.
[0011]
According to the present invention, in a bumper device having at least a crash box disposed between a bumper reinforce and a side member of a vehicle, the crash box extends to a tube with a bottom and a lateral side from an opening edge of the tube. The cross-sectional shape of the tubular body includes the existing flange, and the ratio of the maximum dimension X in the width direction of the vehicle to the maximum dimension Y in the vertical direction, Y / X is in the range of 1.5 to 2.4. Is provided.
[0012]
Further, according to the present invention, in a bumper device having at least a crash box disposed between a bumper reinforce and a side member of a vehicle, the crash box has a bottomed tubular body obtained by deep drawing of a steel plate. And a flange extending laterally from the opening edge of the tubular body, wherein the sectional shape of the tubular body is the ratio of the maximum dimension X in the width direction of the vehicle to the maximum dimension Y in the vertical direction, and Y / X is 1.5. A bumper device is provided that is in the range of ~ 2.4.
[0013]
Further, the present invention employs technical means for setting the starting point of the deformation of the crash box on the bumper reinforce side and connecting the tip of the crash box to the rear wall of the crash box.
The adoption of this means eliminates the need to reduce the diameter of the base of the crash box, that is, the side member side, and eliminates the need to increase the height of the crash box, and reduces the vertical deflection of the bumper reinforce when the vehicle is running. Can be suppressed.
[0014]
According to the present invention, in a bumper device having at least a crash box disposed between a bumper reinforce and a side member of a vehicle, the crash box serves as a starting point of a tube and a deformation at the time of collision of the vehicle and on a side member side. Including the deformed portion that is a valley portion, the cross-sectional shape of the pipe body is the ratio of the maximum dimension X in the width direction of the vehicle to the maximum dimension Y in the vertical direction, and Y / X is in the range of 1.5 to 2.4. , A bumper device is provided.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
The crash box 1 constituting the vehicle bumper device has, for example, a pipe body 2 with a bottom 3 formed by deep drawing a steel plate (sheet thickness: 1.8 to 2.9 mm) of SPC270 material, A flange 4 extending outwardly from the side is formed integrally with the opening edge of the tube body 2.
The flange 4 is fixed to the mounting piece 5-1 of the side member 5 on the vehicle body side, and the bottom 3 is fixed to the bumper reinforce 6. A bolt (not shown) is used for fixing the side member 5 of the tube body 2 to the mounting piece 5-1 and the bumper reinforce 6.
[0016]
The joint portion between the tube 2 and the flange 4 forms a deformed portion 7 as a reversal portion which becomes a valley on the bumper reinforce 6 side. The deformed portion 7 is preferably formed in an arc shape.
By configuring the crush box 1 by deep drawing of a steel plate, the crush box 1 is subjected to work hardening and the strength is improved.
[0017]
FIG. 2 shows a cross section of the tubular body 2. The tubular body 2 has a ratio of the maximum dimension X in the width direction of the vehicle to the maximum dimension Y in the vertical direction, and Y / X of 1.5 to 2.4. Range. R is X / 2.
When Y / X is 1.5 or less, bending occurs in the tubular body 2 at a load input of 30 ° (angle), and when Y / X is 2.4 or more, impact energy due to plastic deformation of the tubular body 2 is obtained. Before the absorption, deformation of the side members is observed, which is not preferable.
The SPC270 steel plate was deep drawn to form a tube 2 having a Y / X of 1.7 and a height of 150 mm. As a result, it was confirmed that the thickness of the cylindrical portion of the tubular body 2 was slightly reduced, the thickness of the flange 4 was increased, and the material strength was more than doubled due to work hardening. It was also confirmed that such an increase in mechanical strength showed strong resistance to bending deformation of the tube 2 due to an impact load.
[0018]
As shown in FIG. 2, the tube 2 is located in the hollow portion of the side member 5, and the flange 4 is fixed to the mounting piece 5-1 at four locations.
By the deep drawing, the thickness of the flange 4 is increased, and the mounting strength is improved. The hollow portion of the side member 5 also has a dimension in the up-down direction larger than the dimension in the vehicle width direction, and the load acting on the pipe body 2 is evenly distributed to the side member 5 and transmitted to the specific position. There is no phenomenon called concentrated load.
[0019]
In the example of FIG. 2, the cross section of the tube body 2 is an ellipse formed by connecting upper and lower circles having a radius (R) of X / 2 with a straight line, but as shown in FIG. It may be a connecting rectangle. R is not less than 2.3 mm and not more than X / 2.
The cross section of the tubular body 2 in the example of FIG. 4 is a deformed hexagon, but each side is connected by an arc of R> 2.3 mm.
The example of FIG. 5 is an example of the tube 2 having an elliptical cross section.
3 to 5, the Y / X ratio is in the range of 1.5 to 2.4.
[0020]
As shown in FIG. 1, when a load (F) due to a collision acts on the bumper reinforce 6, plastic deformation starts from the deformed portion 7, and the pipe 2 sequentially enters the inside of the side member 5, The bumper reinforce 6 approaches the flange 4. Such a plastic deformation of the tubular body 2, that is, a plastic deformation in which the tubular body 2 feeds the deformed portion 7 into the inside of the side member 5 while forming a new arc-shaped deformed portion 7 occurs.
Such plastic deformation indicates a linear deformation along the load upper limit in the stroke / load diagram shown in FIG. 6, and a high energy absorption is possible with a short stroke.
FIG. 6 shows upper and lower stroke / load diagrams of the tubular body 2 having each cross-sectional shape shown in FIGS. 2 to 5. The examples in FIGS. 2 to 5, that is, the tubes having a cross-sectional shape having a dimensional relationship of 1.5 ≦ Y / X ≦ 2.4 show almost the same stroke / load diagram.
[0021]
The example of the crash box 1 shown in FIG. 7 uses a tube 2 having substantially the same configuration as that of the example shown in FIG. 1, but has a deformed portion 7 disposed on the bumper reinforce 6 side. A cover plate 9 having a concave portion 8 that enters the opening of the side member 5 is fixed to the mounting piece 5-1 of the side member 5 at the tip opening of the side member 5.
The bumper reinforce 6 has an opening 10 in which the deformed portion 7, which is a valley on the side member 5 side, is located inside, and the flange 4 contacts the outer surface of the rear wall of the bumper reinforce 6. The bottom 3 of the tube 2 is located in the recess 8 of the cover plate 9.
[0022]
In the example shown in FIG. 7, at least three bolts are tightened from the side of the side member 5 to the nut inside the tube 2 in a state where the bottom 3 of the tube 2 is in contact with the concave portion 8 of the cover plate 9. Thus, the tube 2 is fixed to the side member 5. The cover plate 9 is fixed to the mounting piece 5-1 of the side member 5.
The flange 4 of the tube 2 is bolted to the outer surface of the rear wall of the bumper reinforce 6.
[0023]
When a load acts on the bumper reinforce 6 due to the collision of the vehicle, deformation of the crash box 1 starting from the deformed portion 7 (indicated by phantom lines in FIG. 7) occurs, and the pipes 2 are sequentially moved into the bumper reinforce 6. As the car enters, the bumper reinforce 6 approaches the side member 5. Such a plastic deformation of the tubular body 2, that is, a plastic deformation indicated by an imaginary line in which the tubular body 2 is deformed while forming a new arc-shaped deformed portion 7 occurs. The plastic deformation results in a stroke / load diagram shown in FIG. 6, which enables high energy absorption.
[0024]
In the example shown in FIG. 8, the deformed portion 7-1 of the tubular body 2 is located outside the opening 10 of the bumper reinforce 6, and the deformed portion 7-1 is formed as a step extending outwardly. are doing. The deformed portion 7-1 continues to the flange 4 via the large diameter portion.
The deformed portion 7-1 as a step portion continues to the main body side of the tubular body 2 via an arc surface having a diameter of approximately 1/10 to 1/15 of the inner diameter of the tubular body 2. The other configuration is the same as the example of FIG.
[0025]
In the example shown in FIG. 8 as well, when a load acts on the bumper reinforce 6 due to the collision of the vehicle, plastic deformation indicated by a virtual line starting from the deformed portion 7-1 occurs. In the same manner as described above, the vehicle deformation part 7-1 sends the new deformation part into the bumper reinforce 6 while creating a new deformation part. Thus, also in the example of FIG. 8, the stroke / load diagram shown in FIG. 6 is obtained.
[0026]
The sectional shape of the tubular body 2 shown in FIGS. 7 and 8 is the one shown in FIGS. 3 to 5, but may be a circular sectional shape.
However, the crash box 1 shown in FIGS. 7 and 8 is also formed by, for example, deep drawing a steel plate made of SPC270, as in the examples shown in FIGS.
The tube 2 is fixed to the side member 5 by means of passing a bolt from a side of the side member 5 to a nut fixed to the inner surface of the tube 2 via the cover plate 9 or by welding.
[Brief description of the drawings]
FIG. 1 is a sectional view of a bumper device according to an example of the present invention.
FIG. 2 is a cross-sectional view taken along line II-II in FIG.
FIG. 3 is a sectional view showing a second modification of the tube.
FIG. 4 is a sectional view showing a third modified example of the tubular body.
FIG. 5 is a sectional view showing a fourth modification of the tube.
FIG. 6 is a graph showing a relationship between a stroke and a load.
FIG. 7 is a cross-sectional view of an example in which a deformed portion of a tube is disposed on a bumper reinforce side.
FIG. 8 is a cross-sectional view of an example in which a deformed portion of a tubular body has another shape.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Crash box 2 Tube 3 Bottom 4 Flange 5 Side member 6 Bumpy reinforce 7, 7-1 Deformation (reversal) part

Claims (9)

In a bumper device having at least a crash box disposed between a bumper reinforce and a side member of a vehicle, the crash box includes a tube and a deformed portion having a valley on the bumper reinforce side, A bumper device having a cross-sectional shape in which the ratio of the maximum dimension X in the width direction of the vehicle to the maximum dimension Y in the vertical direction, Y / X, is in the range of 1.5 to 2.4. In a bumper device having at least a crash box disposed between a bumper reinforce and a side member of a vehicle, the crash box serves as a starting point of deformation of a pipe and a vehicle at the time of collision and has a valley on a side member side. Including the deformed portion, the cross-sectional shape of the tubular body is characterized in that the ratio of the maximum dimension X in the width direction of the vehicle to the maximum dimension Y in the vertical direction, Y / X is in the range of 1.5 to 2.4. Bumper device. In a bumper device having at least a crash box disposed between a bumper reinforce and a side member of a vehicle, the crash box has a bottomed tubular body obtained by deep drawing of a steel plate, and a side closer to an opening edge of the tubular body. And the ratio of the maximum dimension X in the width direction of the vehicle to the maximum dimension Y in the vertical direction, Y / X is in the range of 1.5 to 2.4. A bumper device characterized by the above-mentioned. The bumper device according to claim 3, wherein a deformed portion that is a valley on the bumper reinforce side is provided at a joint between the pipe and the flange, and the flange is fixed to the side member. 4. The bumper device according to claim 3, wherein a deformed portion that is a valley on the side member side is provided at a joint portion between the tube and the flange, and the flange is fixed to the bumper reinforce. 4. The bumper device according to claim 3, wherein a step-shaped deformed portion extending outwardly from the side is provided at a joint portion between the tube and the flange, and the flange is fixed to the bumper reinforce. The bumper device according to claim 4, wherein the deformable portion moves into the hollow portion of the side member during a vehicle collision. 7. The bumper device according to claim 5, wherein at the time of a vehicle collision, the deformation portion moves into the hollow portion of the bumper reinforce. 9. The bumper device according to claim 1, wherein the cross-sectional shape of the tube is any one selected from an ellipse, an ellipse, and a polygon.

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