JP2010083459A - Door guard bar for automobile - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce weight while securing an expected energy absorbing characteristic in a door guard bar of an automobile. <P>SOLUTION: This door guard bar has a first horizontal wall 14 on the external force input side and a second horizontal wall 16 on the installing side to a door, and is constituted by being connected by a pair of separate vertical walls 18 and 20 crossing with these first and second horizontal walls 14 and 16 and connecting the first and second horizontal walls 14 and 16. The pair of vertical walls 18 and 20 for connecting the first and second horizontal walls 14 and 16 are formed as an expansively opening structure toward the second horizontal wall 16 from the first horizontal wall 14. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an automobile door guard bar that is a reinforcing member for protecting a passenger against a collision from the side of a vehicle body.

The door guard bar is also referred to as a door impact beam, and functions to absorb collision energy by being deformed with respect to a collision from the side of the vehicle body, and is a reinforcing member for protecting passengers. The door guard bar is disposed so as to extend in the width direction in the space between the inner and outer door panels, and is configured to be attached to the inner door panel at both ends. In order to effectively absorb collision energy by the door guard bar, the first side wall on the external force input side substantially parallel to the door surface and the second side wall on the attachment side are provided on the door. A door guard bar has been proposed in which a horizontal wall is connected by a pair of spaced vertical walls substantially orthogonal to the door surface (Patent Document 1).
Patent No. 3029514

  At the time of a side collision with the door, the outer lateral wall serves as an input side for external force, is subjected to compression, the inner lateral wall is subjected to tension, and both are permanently deformed to absorb collision energy. In this case, the inner lateral wall subjected to the tension tends to be deformed to an outward curved shape, and the pair of vertical walls are pulled relatively inward at the connection portion with the inner lateral wall, and are easily buckled by an external force. Therefore, energy absorption is reduced accordingly. As a countermeasure, in the technique of Patent Document 1, by taking the width and thickness of the inner side wall larger than that of the outer side wall, the stress neutral axis position acting in the cross section by the bending input is moved to the tension side, and a pair of vertical walls is obtained. Inward tension at the connecting portion with the lateral wall inside the wall is suppressed, and the amount of energy absorption is maintained. However, since the width and thickness of the inner side wall are made larger than those of the outer side wall, the weight is increased, and there is a concern about the influence on the peripheral part in a part where layout is difficult.

  In view of the above problems, an object of the present invention is to achieve weight reduction while ensuring the desired energy absorption characteristics.

  The automobile door guard bar of the present invention includes a first lateral wall on the external force input side substantially parallel to the door surface and a second lateral wall on the mounting side of the door, and intersects the first and second lateral walls. The first and second horizontal walls are connected by a pair of spaced apart vertical walls, and the pair of vertical walls has an expanding structure from the first horizontal wall to the second horizontal wall. And

  When an external force is applied to the door guard bar, the inner second horizontal wall is pulled through a pair of vertical walls from the outer first horizontal wall subjected to compression, and the inner side second horizontal wall is advanced by permanent deformation. Since the pair of vertical walls originally opened somewhat downward from the first horizontal wall to the second horizontal wall, the pair of vertical walls becomes nearly upright due to the deformation. Therefore, it is possible to enhance the function of stretching by the vertical wall with respect to the load, and as a result, it is possible to increase the energy absorption efficiency.

  In the present invention, it is preferable that at least one of the pair of vertical walls connects the first horizontal wall to the second horizontal wall at an inclination angle of 3 to 6 °.

  The energy absorption efficiency of the door guard bar at the time of deformation can be increased, the cross-sectional area of the door guard bar with respect to the required energy absorption amount can be reduced correspondingly, and the amount of material used can be reduced, so the material cost can be reduced. Can do.

  1 and 2, reference numeral 10 denotes an inner door panel (inner panel). A door guard bar 12 is attached to the inner door panel 10, and an outer door panel (outer panel) 13 is attached to the inner door panel 10 with the door guard bar 12 interposed therebetween (FIG. 2). ) Is attached. In other words, the door guard bar 12 is disposed between the inner and outer door panels 10 and 13. As shown in FIG. 1, the door guard bar 12 is slightly inclined but extends in the width direction, and both end portions 12-1 and 12-2 constitute attachment portions to the inner door panel 10. The inner door panel 10 is formed such that the outer peripheral portion 10-2 below the opening 10-1 for the window is slightly raised, and the both ends 12-1, 12-2 of the door guard bar 12 are formed on the raised portion 10-2. Is fixed by welding or the like.

  In the embodiment of the present invention, the door guard bar 12 is made of aluminum or aluminum alloy, and is formed by extrusion so as to form the cross-sectional shape shown in FIG. That is, the door guard bar 12 includes a first lateral wall 14 extending in parallel to the door general surface, a second lateral wall 16 parallel to the first lateral wall 14 that is somewhat narrower than the first lateral wall 14, and The first lateral wall 14 and the second lateral wall 16 intersect with each other, and the first lateral wall 14 and the second lateral wall 16 are connected to each other. As shown in FIG. 2, the first lateral wall 14 is positioned on the outer door panel 13 side (external force input side), and the second lateral wall 16 is positioned on the inner door panel 10 side. The door guard bar 12 is fixed to the inner door panel 10 on the second lateral wall 16 by welding or the like. That is, both end portions of the second lateral wall 16 become fixing portions 12-1 and 12-2 to the outer peripheral portion 10-2 of the inner door panel 10. On the other hand, the first lateral wall 14 faces the outer door panel 13 but is not fixed. That is, when an external force is applied to the door, the external force deforms the outer door panel 13 so that the outer door panel 13 comes into contact with the first lateral wall 14, and as a result, the external force is greater than the first lateral wall 14 to the vertical walls 18, 20. It is received by the second horizontal wall 16 (fixed to the inner door panel 10) via the door, and external force is absorbed by deformation of the door guard bar 12 at that time.

  According to the present invention, as shown in FIG. 3, the pair of vertical walls 18, 20 has a somewhat expanded structure from the first horizontal wall 14 toward the second horizontal wall 16. The vertical walls 18 and 20 are smoothly connected to the first and second horizontal walls 14 and 16 at an angle θ of 3 to 6 degrees. FIG. 4 shows a cross-sectional shape of a conventional door panel disclosed in Patent Document 1, and a pair of vertical walls 18A connecting the first and second horizontal walls 14A, 16A and the first and second horizontal walls 14A, 16A. 20A is the same as that of the present invention. However, in the conventional door panel shown in FIG. 4, the first and second horizontal walls 14A, 16A and the pair of vertical walls 18A, 20A are orthogonal to each other. The difference is that a somewhat expanded structure is formed from one lateral wall 14 to the second lateral wall 16. Such a structure of the door guard bar 12 of the present invention can improve the reaction force performance (energy absorption performance at the time of collision) in a bending test, and can realize weight reduction correspondingly.

  In the bending test for evaluating the energy absorption performance of the door guard bar 12 at the time of collision, the door guard bar 12 is placed on the first horizontal wall 14 and the second horizontal wall 16 under the bending test machine as shown in FIG. The loader 22 is placed on a pair of spaced-apart support tables 21, and a load element 22 having a downward semicircular cross section is brought into contact with the door guard bar 12 at the center between the support tables 21, and the load element 22 is lowered. Apply a vertical load to the door guard bar 12 by going. In the process of deformation, the upper first lateral wall 14 that abuts against the load 22 is subjected to compression, and the second lateral wall 16 connected to the first lateral wall 14 by starting a pair of longitudinal walls 18 and 20 is subjected to tension. These are brought to permanent deformation (plastic deformation). The deformation applied to the door guard bar 12 by lowering the loader 22 increases the reaction force up to a certain deformation amount. However, if it exceeds the limit and buckles or breaks, the reaction force can no longer increase any more. This is the maximum shock absorption amount, and the shock absorption performance of the door guard bar 12 is evaluated based on this value. And it is desired to further reduce the weight of the door guard bar 12 while maintaining the desired shock absorbing performance.

  In the present invention, a conventional door guard bar structure in which the vertical walls 18A, 20A are orthogonal to the first and second horizontal walls 14A, 16A shown in FIG. By making the vertical walls 18, 20 slightly open from the first horizontal wall 14 to the second horizontal wall 16, the door guard bar can be made lighter while maintaining the desired shock absorption performance. Is realized. That is, in FIG. 5, the load guard 22 is displaced as indicated by an imaginary line 22 ', and the door guard bar 12 is bent in the longitudinal direction as indicated by an imaginary line 12' and enters a permanent deformation region. In the other cross section, in FIG. 6, the first lateral wall 14 with which the load 22 is in direct contact is subjected to compression, and this compressive force is passed through a pair of spaced longitudinal walls 18, 20 at both ends of the first lateral wall 14. The second lateral wall 16 is applied to both ends of the second lateral wall 16, and the first lateral wall 14 receives a tensile force. The shape of the door guard bar 12 in the deformed state is indicated by an imaginary line, and the first lateral wall 14 to be compressed is warped somewhat downward as indicated by an imaginary line 14 ', and the second lateral wall 16 to be pulled is applied. Warps upward like an imaginary line 16 '. As a result, the pair of vertical walls 18 and 20 are deformed so as to open upward as indicated by imaginary lines 18 ′ and 20 ′. That is, before the load, the pair of vertical walls 18 and 20 was in a state where the top was narrow and the bottom was wide (lower open state), but when receiving the load, the bottom was narrowed and the top was widened, In other words, the pair of vertical walls 18 and 20 are close to the upright state as shown by imaginary lines 18 ′ and 20 ′ after the deformation from the downwardly opened state before the deformation shown by the solid line in FIG. Therefore, the tension function by the vertical wall is enhanced with respect to the load. On the other hand, the deformed shape in the case of a door guard bar having a conventional structure is shown by an imaginary line in FIG. 7, and the first lateral wall 14A that is compressed by a load warps somewhat downward as shown by an imaginary line 14A ′. The second lateral wall 16A subjected to tension warps upward as indicated by an imaginary line 16A ′. As a result, the pair of vertical walls 18A and 20A is similarly deformed to open upward as indicated by imaginary lines 18A ′ and 20A ′. However, in the conventional case, the vertical walls 18A, 20A before deformation are in the direction parallel to the load, but the vertical wall falls down like the imaginary lines 18A ', 20A' due to the load. Rather it declines. As a result, the energy absorption function superior to the conventional structure (FIG. 7) can be obtained by the structure of the present invention (FIG. 6). According to the analysis results of the finite element method model by the applicant, the length and thickness of the first and second horizontal walls are the same in the present inventions 14 and 16 and the conventional 14A and 16A, and the vertical walls are also the same. When the thickness is the same for the samples 18 and 20 of the present invention 18 and 20A and 20A, and the same energy absorption is used for the present invention and the conventional, the cross-sectional area of the door guard bar 12 of the present invention is the conventional door guard bar. It was confirmed that it could be reduced by 1.0% with respect to that of 14. That is, the structure of the door guard bar 12 (FIG. 3) of the present invention is larger in length than the vertical walls 18A and 20A of the conventional door guard bar (FIG. 4) because the vertical walls 18 and 20 are open downward. Is a factor that increases the cross-sectional area. However, in the downward opening structure of the vertical walls 18 and 20 in the present invention, the radius of curvature of the connecting portions a and b (FIG. 3) having an obtuse angle has a large value, so that the reduction margin can be increased. Although the radius of curvature increases at the connection portions c and d having an acute angle, the increase is small because the value is originally small, and the cross-sectional area at the R portion is reduced in total. Since the total cross-sectional integral decrease at the R portion is the cross-sectional area increase due to the downward opening structure of the vertical walls 18 and 20, the total cross-sectional area is the door guard bar of the present invention (FIG. 3) <the conventional door guard bar. (FIG. 4).

  In the embodiment of FIG. 8, the first horizontal wall 114 and the second horizontal wall 116 are connected by a pair of vertical walls 118, 120, as in the first embodiment, but a pair of vertical walls 118, 120 are connected. In order to open downward from the first lateral wall 114 to the second lateral wall 116, the pair of longitudinal 118, 120 is curved outward.

  9 is similar to the first embodiment in that the first horizontal wall 214 and the second horizontal wall 216 are connected by a pair of vertical walls 218, 220, but the pair of vertical walls 218, The inner wall surface of 220 is orthogonal to the first and second horizontal walls 214 and 216, but by gradually increasing the thickness of the vertical walls 218 and 220 from the first horizontal wall 214 toward the second horizontal wall 216, The outer wall surface is inclined downward. Accordingly, the center lines of the pair of vertical walls 218 and 220 are opened downward, and in this embodiment as well, the pair of vertical walls 218 and 220 are in a state where the first horizontal wall 214 is inclined to the second horizontal wall 216 (vertical). The walls 218 and 220 are connected at an angle of inclination with respect to the vertical direction of the center line of the walls 218 and 220, and the same effects as those of the first embodiment can be realized.

  In the embodiment of FIG. 10, the first horizontal wall 314 and the second horizontal wall 316 are connected by a pair of vertical walls 318 and 320 as in the above embodiment, but one of the pair of vertical walls is also connected. Although the vertical wall 318 is vertical, the other vertical wall 320 is inclined, thereby realizing a structure in which a pair of vertical walls 318 and 320 are opened downward from the first horizontal wall 314 to the second horizontal wall 316. Thus, the operational effects according to the above-described embodiment can be realized.

FIG. 1 is a front view of an inner door panel to which a door guard bar of the present invention is attached. 2 is a cross-sectional view taken along line II-II in FIG. FIG. 3 is an enlarged cross-sectional view of the door guard bar in FIG. FIG. 4 is a sectional view of a door guard bar in the prior art. FIG. 5 is a schematic configuration diagram of a testing device for the energy absorption amount of the door guard bar by a bending tester. FIG. 6 is the same as FIG. 3, but schematically shows the deformation state during the bending test of the door guard bar of the present invention. FIG. 7 is the same as FIG. 4, but schematically shows the deformation state during the bending test of the door guard bar of the present invention. FIG. 8 is a sectional view of a door guard bar according to another embodiment of the present invention. FIG. 9 is a sectional view of a door guard bar in another embodiment of the present invention. FIG. 10 is a sectional view of a door guard bar in another embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Inner door panel 12 ... Door guard bar 13 ... Outer door panel 14 ... Outside (door force input side) side wall 16 of door guard bar 16 ... Inside (door installation side) side wall of door guard bar
18, 20 ... Vertical wall of door guard bar 21 ... Bending test machine support 22 ... Bending test machine loader

Claims (2)

  A first lateral wall on the external force input side substantially parallel to the door surface and a second lateral wall on the mounting side of the door are provided, intersecting the first and second lateral walls, and the first and second lateral walls A door guard bar for automobiles connected by a pair of spaced apart vertical walls connecting the two, wherein the pair of vertical walls has an expanding structure from the first lateral wall to the second lateral wall. bar.   2. The automobile door guard bar according to claim 1, wherein at least one of the pair of vertical walls connects the first horizontal wall to the second horizontal wall at an inclination angle of 3 to 6 [deg.].

Images