Source: https://patents.google.com/patent/US20090085362A1/en
Timestamp: 2018-08-15 23:44:01
Document Index: 120321051

Matched Legal Cases: ['§119', 'Application No. 2007', 'art 33', 'art 34', 'art 3', 'art 3', 'arts 3', 'art 3', 'art 3', 'art 3', 'arts 3', 'arts 3', 'art 33', 'art 103', 'art 103']

US20090085362A1 - Vehicle structure for automobile - Google Patents
US20090085362A1
US20090085362A1 US12210282 US21028208A US2009085362A1 US 20090085362 A1 US20090085362 A1 US 20090085362A1 US 12210282 US12210282 US 12210282 US 21028208 A US21028208 A US 21028208A US 2009085362 A1 US2009085362 A1 US 2009085362A1
US12210282
US7926865B2 (en )
A vehicle structure for an automobile includes: a bumper beam extending in a car width direction; a crash box extending in a longitudinal direction of the automobile and connected at a distal end thereof to a side part in the car width direction of the bumper beam; and a mounting plate having a face to which a base end of the crash box is connected and another face mounted to a distal end of a vehicle frame extending in the longitudinal direction of the automobile by means of fasteners. The crash box is in a substantially cross shape in closed section.
This non-provisional application claims priority under 35 U.S.C. §119(a) on Patent Application No. 2007-257097 filed in Japan on Oct. 1, 2007, the entire contents of which are hereby incorporated by reference.
Formation of the trench in the crash box in a flat polygonal shape in section results in that the direction that the trench is deformed and the direction that the other part is deformed upon receipt of an impact load are reverse to each other to be cancelled, so that the crush boxes can be buckled and deformed appropriately in the axial direction thereof.
A vehicle structure for an automobile in accordance with the present invention includes: a bumper beam extending in a car width direction; a crash box extending in a longitudinal direction of the automobile and connected at a distal end thereof to a side part in the car width direction of the bumper beam; and a mounting plate having a face to which a base end of the crash box is connected and another face mounted to a distal end of a vehicle frame extending in the longitudinal direction of the automobile by means of fasteners, wherein the crash box is in a substantially cross shape in closed section.
In the above arrangement, the lengths of the sides are set almost equal to each other to equalize the “collapse pitch,” which varies depending on the lengths of the sides, in the entire periphery of the closed section, so that the deformation modes that the crash box is buckled and deformed can be caused stably.
In one aspect of the present invention, the vehicle frame is in a vertically oblong rectangular shape, and four protrusions of the crash box in the substantially cross shape in closed section extend in a vertical direction and a transverse direction of the automobile so that: an upper end wall of an upper protrusion of the four protrusion of the crash box agrees with an upper wall of the vehicle frame when viewed from front while a lower end wall of a lower protrusion of the four protrusions thereof agrees with a lower wall of the vehicle frame when viewed from the front.
In the above arrangement, the upper end wall of the upper protrusion of the crash box in the substantially cross shape in closed section substantially agrees with the upper wall of the vehicle frame when viewed from the front while the lower end wall of the lower protrusion thereof agrees with the lower wall of the vehicle frame when viewed from the front. Accordingly, the crash box is overlapped at both the upper and lower protrusions and the right and left protrusions thereof with the vehicle frame in the vertically oblong rectangular shape in section.
In one aspect of the present invention, the vehicle frame is in a vertically oblong rectangular shape, and four protrusions of the crash box in the substantially cross shape in closed section are inclined with respect to the vertical direction of the automobile so that the side walls of the protrusions are intersected at central parts in the vertical direction of the crash box with side walls of the vehicle frame when viewed from front.
In one aspect of the present invention, a reinforcing member extending in the transverse direction of the automobile is provided to the vehicle frame so as to agree with one of protrusions of the crash box which extends in the transverse direction thereof when viewed from the front.
In the above arrangement, the reinforcing member extending in the transverse direction is provided at the vehicle frame in the vertically oblong rectangular shape so that the vehicle frame and the reinforcing member form a substantially cross shape which substantially agrees with the substantially cross shape in closed section of the crash box.
FIG. 7 shows difference in deformation state of the crash box where a load input direction is different, wherein FIG. 7A is a plan view of the crash box before deformation, FIG. 7B is a plan view of the crash box deformed upon head-on collision, and FIG. 7C is a plan view of the crash box deformed upon offset collision.
A vehicle structure for an automobile in accordance with Embodiment 1 will be described first with reference to FIG. 1 to FIG. 4. FIG. 1 is a perspective view of a front end part in the vehicle structure employing the present invention, FIG. 2 is an overall perspective view of a crash box in accordance with the present embodiment, FIG. 3 is a detailed front view showing the positional relationship between the crash box and a front side frame on the right side of a vehicle, and FIG. 4 is a perspective view of a reinforcing bracket provided at the front side frame.
As shown in FIG. 1, the vehicle structure at the front end part of a vehicle includes: pair of right and left front side frames 1, 1 extending in the longitudinal direction of the vehicle; a bumper beam 2 extending in the car width direction on the vehicle front side of the front side frames 1,1; a pair of right and left crash boxes 3, 3 extending rearward of the vehicle from the side ends in the car width direction of the bumper beam 2; and set plates 4, 4 fastening and fixing the crash boxes 3, 3 to the front side frames 1, 1.
Each set plates 4 is formed of a metal-made plate member in a substantially square shape, at each corner of which a joint hole 41 is formed. A bolt B and a nut N are engaged with each other through each joint hole 41 for fastening and fixing the corresponding set plate 4 to the front end of the corresponding front side frame 1. The base end parts (the rear end parts) 3 a, 3 a of the crash boxes 3, 3 are bonded and fixed to the front faces of the set plates 4, 4.
Each of the crash boxes 3, 3 is formed, as shown in FIG. 2, in such fashion that the two bent members 31, 32 are combined with each other from right and left and an overlap part 33 a of an upper end wall 33 and an overlap part 34 a of a lower end wall 34 are spot-welded vertically.
Accordingly, each crash box 3 has a substantially cross shape (a substantially boxed cross shape, see FIG. 3) in closed section. Specifically, each crash box 3 is set as follows.
This cross shape in closed section is so formed that substantially rectangular protrusions 35, 36, 37, 38 are formed to protrude upward, downward, rightward, and leftward. The lengths L of the sides of the protrusions 35, 36, 37, 38 are set almost equal to each other. Each angle α that the corners 39, 40 form is set substantially at a right angle (90 degrees).
Further, as shown in FIG. 2, the total length D of each crash box 3 is set equal to or larger than a predetermined length so that each crash box 3 can absorb the impact energy sufficiently upon receipt of an impact load.
As shown in FIG. 3, the plate thickness Ct of the crash boxes 3, 3 is set smaller than the plate thickness Ft of the front side frames 1, 1 so that the crash boxes 3, 3 can be buckled and deformed upon receipt of an impact load from the front of the vehicle earlier than the front side frames 1, 1.
The base end part 3 a of each crash box 3 is joined by fillet-welding W the entire periphery thereof to the front face of the corresponding set plate 4 firmly, as shown in FIG. 2.
An upper end wall 33 at the upper protrusion 35 of each crash box 3 substantially agrees with an upper wall 1 a of the corresponding front side frame 1 when viewed from the front while a lower end wall 34 at the lower protrusion 36 of each crash box 3 substantially agrees with a lower wall 1 b of the corresponding front side frame 1 when viewed from the front, as shown in FIG. 3.
The side walls 38 a, 38 b at the right protrusion 38 of each crash box 3 are intersected with a right wall 1 d of the corresponding front side frame 1 when viewed from the front while the side walls 37 a, 37 b at the left protrusion 37 of each crash box 3 are intersected with a left wall 1 c of the corresponding front side frame 1 when viewed from the front.
At the right wall 1 d and the left wall 1 c of each front side frame 1, the aforementioned reinforcing brackets 15, 15 are provided correspondingly to the right protrusion 38 and the left protrusion 37 of the corresponding crash box 3.
Specifically, as shown in FIG. 4, the reinforcing brackets 15, 15 extending in the longitudinal direction of the vehicle are provided at the front end parts of the left wall 1 c and the right wall 1 d of each front side frame 1 (only the left wall 1 c is shown in FIG. 4), respectively.
Each reinforcing bracket 15 includes a plate joint flange 15 a joined to the corresponding set plate 4, a frame joint flange 15 b joined to the corresponding front side frame 1, and triangular joint beams 15 c, 15 c extending in the longitudinal direction of the vehicle to bridge between and connect the joint flanges 15 a, 15 b.
Provision of the reinforcing brackets 15, 15 allows an impact load transmitted from the right protrusions 38 and the left protrusions 37 (see FIG. 3) of the crash boxes 3, 3 to be transmitted from the set plates 4, 4 to the front side frames 1, 1 to achieve definite support.
Further, as shown in FIG. 3, each left protrusion 37 and each right protrusion 38 of the crash boxes 3, 3 are so set that the width Q2 of the distal part thereof is smaller than the width Q1 of the base part thereof.
A plurality of notches 51, 52, 53 are formed in the front end part 3 b of each crash box 3.
Specifically, as shown in FIG. 2 and FIG. 3, center notches 51, 51 extending in the vertical direction are formed in the central parts in the vertical direction of right and left end walls 38 c, 37 c of the right and left protrusions 37, 38. Further, upper notches 52 and lower notches 53 are formed in the side walls 35 a, 35 b of the upper protrusion 35 and the side walls 36 a, 36 b of the lower protrusion 36, respectively, so as to extend from the central parts in the vertical direction of the upper and lower protrusions 35, 36 to the base ends of the right protrusion 38 and the left protrusion 37 with the inwardly folded ridges 39 interposed.
Though not shown specifically, parts of the front end parts 3 b other than the notches 51, 52, 53 are welded and fixed to the bumper beam 2 by fillet welding.
Behavior that the crash boxes 3, 3 are deformed will be described next with reference to FIG. 5 to FIG. 8. FIG. 5 is a schematic view for explaining a deformation state of the substantially cross shape in closed section of one of the crash boxes, FIG. 6 is a perspective view showing the deformation state of the crash box, FIG. 7 presents plan views showing the difference in deformation of the crash box where a load input direction is different, and FIG. 8 is a load diagram showing the load-deformation amount curves of the crash box where the load input direction is different.
As shown in FIG. 5, upon receipt of an impact load, the crash box 3 alternatively causes two deformation patterns T1, T2 deformed from the square cross shape BF as the initial shape in section indicated on the left side to be buckled and deformed.
The two deformation patterns caused are a first deformation pattern T1 indicated at upper right and a second deformation pattern T2 indicated at lower right in FIG. 5.
In the first deformation pattern T1, the upper protrusion 35 and the lower protrusion 36 are deformed as if they are pulled upward and downward, respectively, while the upper and lower side walls 38 a, 38 b of the right protrusion 38 and the upper and lower side walls 37 a, 37 b of the left protrusion 37 are deformed as if they are also pulled upward and downward, respectively.
In contrast, in the second deformation pattern T2, the right protrusion 38 and the left protrusion 37 are deformed as if they are pulled leftward and rightward (transversely), respectively, while the side walls 35 b, 35 a of the upper protrusion 35 and the right and left side walls 36 b, 36 a of the lower protrusions 36 are deformed as if they are also pulled leftward and rightward, respectively.
Specifically, as shown in FIG. 6, the first deformation pattern T1 and the second deformation pattern T2 are caused alternately from the front end part 3 b toward the rear end part 3 a of the crash box 3 while buckling and deformation are repeated, so that the crash box 3 is compressed in the axial direction thereof to thus absorb the impact energy.
Referring to FIG. 7, difference in deformation of the crash box 3 will be described which is caused where a load input direction is different. FIG. 7A is a plan view of the crash box before deformation, FIG. 7B is a plan view showing a deformation state of the crash box upon head-on collision, and FIG. 7C is a plan view showing a deformation state of the crash box upon offset collision.
Buckling and deformation of the cross shape in closed section of the crash box 3 are repeated at head-on collision, as described previously, to cause compression of the crash box 3 in the longitudinal direction of the automobile (the axial direction of the crash box 3), as shown in FIG. 7B. Thus, the crash box 3 absorbs the impact energy at head-on collision of the vehicle.
In contrast, as shown in FIG. 7C, the crash box 3 is deformed with its front end face 3c slightly slanted sideways.
Nevertheless, no falling deformation is caused in the crash box 3 and only slight buckling and deformation is caused at the front end part 3 b thereof because the crash box 3, which includes the right protrusion 38 and the left protrusion 37, has a large section modulus in the car width direction (the transverse direction) to have increased rigidity in the direction where it falls.
As can be understood from the drawings, when a colliding object Z collides with the vehicle from the left front (see FIG. 9A), the left part in the car width direction of the bumper beam 2 at the front end of the vehicle is deformed to retreat large (see FIG. 9B).
In the present embodiment, the four protrusions 35, 36, 37, 38 of the cross shape in closed section of the each crash box 3 extend in the vertical direction and the transverse direction, and the upper end wall 33 of the upper protrusion 35 and the lower end wall 34 of the lower protrusion 36 substantially agree with the upper wall 1 a and the lower wall 1 b of the corresponding front side frame 1, respectively, when viewed from the front.
In this arrangement, the crash boxes 3, 3 in the substantially cross shape in closed section are overlapped at the upper protrusions 35 and the lower protrusion 36 thereof with the front side frames 1, 1 in the vertically long rectangular shape, so as to be intersected at the side walls 38 a, 38 b, 37 a, 37 b of the right protrusion 38 and the left protrusion 37 thereof with the front side frames 1, 1 when viewed from the front.
Accordingly, the base end parts 3 a, 3 a of the crash boxes 3, 3 are supported definitely by the front side frames 1, 1 at receipt of an impact load to cause the crash boxes 3, 3 to be buckled and deformed, thereby allowing the crash boxes 3, 3 to absorb the impact energy.
Further, the reinforcing brackets 15, 15 are provided at the front end parts of each front side frame 1 so as to agree with the right protrusion 38 and the left protrusion 37 of the corresponding crash box 3 when viewed from the front.
Accordingly, the base end parts 3 a, 3 a of the crash boxes 3, 3 are entirely supported at receipt of an impact load to cause definite buckling and deformation of the entire peripheries of the crash boxes 3, 3, thereby allowing the crash boxes 3, 3 to absorb the impact energy.
Furthermore, in the present embodiment, each reinforcing bracket 15 is composed of the plate joint flange 15 a, the frame joint flange 15 b, and the triangular joint beams 15 c, 15 d connecting the joint flanges 15 a, 15 b.
Accordingly, the joint beams 15 c, 15 d exhibit the tensile force upon receipt of an impact load, which means that the reinforcing brackets 15, 15 additionally increases the rigidity for supporting the crash boxes 3, 3.
Each triangular joint beams 15 c, 15 d is narrow as it goes away from the front end part of the corresponding front side beam 1. Hence, the joint beams 15 c, 15 d will not hinder arranging, for example, the shroud panel or the like (not shown) aside the corresponding front side frame 1.
Each reinforcing bracket 15 includes the triangular joint beams 15 c, 15 d in the present embodiment but is not limited to this shape. The reinforcing brackets 15, 15 may be brackets in an L shape in section. Alternatively, reinforcing plates or the like of which shape substantially agrees with the cross shape of the corresponding crash box 3 may be bonded to the reverse faces of the set plates 4, 4.
In addition, each crash box 3 is formed by overlaying the two bent members 31, 32 and spot-welding the overlap part 33 a of the upper end wall 33 of the upper protrusion 35 and the overlap portion 34 a of the lower end wall 34 of the lower protrusion 36.
A crash box 103 is different from the crash box 3 of Embodiment 1 in the shape of the trigger for causing buckling and deformation. Namely, inwardly folded beads 151, 152, 153 extending in the vertical direction are formed in the side walls at the front end part 103 b of the crash box 103, rather than the notches 51, 52, 53.
Specifically, an upper inwardly folded bead 151 is formed in each of the side walls 35 a, 35 b of the upper protrusion 35, a lower inwardly folded bead 152 is formed in each of the side walls 36 a, 36 b of the lower protrusion 36, and a central inwardly folded bead 153 is formed in each of the right end wall 38 c of the right protrusion 38 and the left end wall 37 c of the left protrusion 37.
Formation of the inwardly folded beads 151, 152, 153 in the respective walls causes, upon receipt of an impact load, the aforementioned first deformation mode T1 from a front end part 103 b of the crash box 103. Namely, the first deformation mode T1 is caused upon receipt of a compression load from the front of the vehicle in such a way that a part of the crash box 103 where the inwardly folded parts are not formed is deformed so as to be extruded outward by utilizing the counterwork against inward folding of the part thereof where the inwardly folded beads 151, 152, 153 are formed.
With this arrangement of the crash box 203, the positional relationship thereof with the front side frame 1 becomes different from that in Embodiment 1. Namely, the protrusions 235, 236, 237, 238 of the crash box 203 are intersected with the right and left side walls 1 d, 1 c of the side frame 1 when viewed from the front. More specifically, side walls 235 a, 236 a, 237 a, 238 a in the central part in the vertical direction of the crash box 3 and peripheral walls 235 b, 236 b, 237 b, 238 b of the protrusions 235, 236, 237, 238 are intersected with the side walls 1 c, 1 d of the front side frame 1 when viewed from the front.
Specifically, since the crash box 203 is arranged to form the substantially X shape against the front side frame 1 in the transversely oblong rectangular shape, all the four protrusions 235, 236, 237, 238 can be caught by the front side frame 1 definitely regardless of each position of the upper wall la and the lower wall 1 b of the front side frame 1.
As described above, in the present embodiment, the four protrusions 235, 236, 237, 238 of the crash box 203 in the cross shape in closed section are arranged so as to extend in diagonally so that the central parts in the vertical direction of the side wall 235 a, 236 a, 237 a, 238 a of the protrusions 235, 236, 237, 238 are intersected with the side walls 1 c, 1 d of the front side frame 1 when viewed from the front.
1. A vehicle structure for an automobile, comprising:
a bumper beam extending in a car width direction;
a crash box extending in a longitudinal direction of the automobile and connected at a distal end thereof to a side part in the car width direction of the bumper beam; and
a mounting plate having a face to which a base end of the crash box is connected and another face mounted to a distal end of a vehicle frame extending in the longitudinal direction of the automobile by means of fasteners,
wherein the crash box is in a substantially cross shape in closed section.
2. The vehicle structure of claim 1, wherein
joint holes through which the fasteners are inserted are formed at four corners of the mounting plate, and
protrusions of the crash box in the substantially cross shape in closed section are arranged between the joint holes.
3. The vehicle structure of claim 1, wherein
4. The vehicle structure of claim 1, wherein
an upper end wall of an upper protrusion of the four protrusion of the crash box agrees with an upper wall of the vehicle frame when viewed from front while a lower end wall of a lower protrusion of the four protrusions thereof agrees with a lower wall of the vehicle frame when viewed from the front.
5. The vehicle structure of claim 1, wherein
four protrusions of the crash box in the substantially cross shape in closed section are inclined with respect to the vertical direction of the automobile so that the side walls of the protrusions are intersected at central parts in the vertical direction of the crash box with side walls of the vehicle frame when viewed from front.
6. The vehicle structure of claim 2, wherein
7. The vehicle structure of claim 1, wherein
the crash box is formed by overlaying a plurality of members and spot-welding wall faces thereof overlapped with each other, the wall faces being peripheral walls of protrusions of the substantially cross shape in closed section.
8. The vehicle structure of claim 4, wherein
a reinforcing member extending in the transverse direction of the automobile is provided to the vehicle frame so as to agree with one of protrusions of the crash box which extends in the transverse direction thereof when viewed from the front.
9. The vehicle structure of claim 8, wherein
a frame mounting face mounted to a side face of the vehicle frame;
a plate mounting face mounted to the other side face of the mounting plate; and
a beam part extending in the longitudinal direction of the automobile between the frame mounting face and the plate mounting frame, the beam being narrow in the car width direction as it goes away from the distal end of the vehicle frame.
US12210282 2007-10-01 2008-09-15 Vehicle structure for automobile Active 2029-04-18 US7926865B2 (en)
JP2007-257097 2007-10-01
US20090085362A1 true true US20090085362A1 (en) 2009-04-02
US7926865B2 US7926865B2 (en) 2011-04-19
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Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:TERADA, SAKAYU;KOWAKI, MIHO;NAKAYAMA, NOBUYUKI;REEL/FRAME:021528/0230