Vehicle front structure

Abstract

Upper crash boxes (4) are fastened to front ends of a pair of right and left front side members (1) via flange parts (1a, 4a). A pair of right and left front suspension members (7) are disposed below the upper crash boxes. Lower crash boxes (10) are fastened to front ends of the front suspension members (7), via flange parts (7a, 10a), by inner and outer fasteners (13out) that are arranged opposite to each other. Front ends of the upper and lower crash boxes (4, 10) are connected to the front ends of the front suspension members via bumper reinforcement sides (15). The respective fasteners (13in, 13out) are arranged to be separated from the outer surfaces of the lower crash boxes (10) so as to facilitate deformation of the flange parts (7a, 10a). During a small frontal overlap crash, the lower crash boxes (10) are rotationally displaced, in a plan view, while the flange parts (7a, 10a) are deformed, whereby horizontal displacement of a vehicle body is induced.

Description

[Technical field]

[0001] The present invention relates to a front structure of a vehicle. [Background technology]

[0002] As a conventional front structure for this type of vehicle, for example, Patent Document 1 discloses a crash box that absorbs a collision load during a frontal collision of the vehicle, which is provided at the front ends of a pair of left and right side members that make up a subframe. A fixed flange member is provided at the front end of the side member, and a connecting flange member is provided at the rear end of the crash box, and these flange members are overlapped on top of each other and fastened together with bolts and nuts.

[0003] The nut on the fixed flange member side is integrally formed with a horizontally long flange, with the short side of the horizontally long flange facing the front suspension member. This horizontally long flange serves to suppress deformation of the connecting flange member when a vehicle crashes head-on and a collision load is input to the crash box, and to suppress collapse of the crash box due to deformation of the connecting flange member. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2010-202093 A Summary of the Invention [Problem to be solved by the invention]

[0005] The horizontal flanges in Patent Document 1 are intended to obtain the desired effect of absorbing the collision load by suppressing the collapse of the crash boxes. Therefore, in the event of a full-overlap frontal collision, the crash load is absorbed by the crushing of the crash boxes and transmitted to the subframe, contributing to improving the strength in the fore-and-aft direction of the vehicle body, but it is difficult to say that this is sufficient to deal with offset frontal collisions.

[0006] In an offset frontal collision, in which another vehicle or obstacle strikes a biased portion of the front of the vehicle body, particularly in a small overlap frontal collision (e.g., 25% overlap), the other vehicle or obstacle strikes a portion of the vehicle width that is further outboard than either the left or right side member. As a result, the crash box is not subjected to the collision load from the front, and the expected crushing and subsequent transmission of the collision load to the subframe may not be achieved. Therefore, there is still room for improvement in terms of improving the strength of the vehicle in the fore-and-aft direction in offset frontal collisions.

[0007] The present invention has been made to solve these problems, and its object is to provide a front structure for a vehicle that can effectively utilize crash boxes to reduce the amount of deformation of the vehicle body during an offset frontal collision. [Means for solving the problem]

[0008] In order to achieve the above object, a front structure for a vehicle of the present invention comprises a pair of left and right front suspension members constituting a subframe of a vehicle body, and a pair of left and right first crash boxes respectively connected to front ends of the front suspension members, each of the first crash boxes being connected to the front suspension members such that a front portion of the first crash box is rotated and displaced outwardly of the vehicle width when a collision load is input due to an offset frontal collision with the vehicle body, and each of the front suspension members and each of the first crash boxes has a base portion extending in the fore-and-aft direction of the vehicle body, and a flange portion extending outward from the end of the base, and each of the front suspension members and each of the first crash boxes are fastened to each other by overlapping the flange portions with each other at multiple fastening portions, and each of the fastening portions includes at least an inner fastening portion located on the inner side of the vehicle width and an outer fastening portion located on the outer side of the vehicle width, and the inner fastening portion is spaced apart from the outer surface of the base of the front suspension member and the outer surface of the base of the first crash box, and the inner fastening portion and the outer fastening portion are arranged only at two diagonal points of the cross section of the first crash box.

[0009] Therefore, when an offset front collision occurs due to another vehicle or an obstacle, the collision load is input to the first crash box on either the left or right side. At this time, the first crash box rotates and displaces so that the front end moves outward in the vehicle width, and is in a state of tension between the other vehicle or obstacle and the front end of the front suspension member. Since the collision load is transmitted from such a first crash box to the front end of the front suspension member, a lateral displacement occurs in the vehicle body, improving the vehicle body passing effect. In addition, because the inner fastening parts are disposed at a distance from the outer surface of the base of the front suspension member and the outer surface of the base of the first crash box, the area of ​​the flange part between them can deform while maintaining fastening by the inner fastening parts. The base of the first crash box rotates around the outer end while separating the inner end parts, but the deformation of the flange parts allows the inner end parts to separate without damaging the inner fastening parts. In addition, the flange portions are fastened to the inner and outer fastening portions located at only two diagonal points on the cross section of the first crash box, ensuring that the flange portions overlap, and reducing the number of fastening portions reduces manufacturing costs.

[0010] In another aspect, the vehicle may further include a pair of left and right front side members respectively arranged above each front suspension member, a pair of left and right second crash boxes respectively connected to the front ends of each front side member, and a pair of left and right bumper force sides respectively connecting the front ends of the first crash boxes and the front ends of the second crash boxes on both the left and right sides of the vehicle body.

[0011] Therefore, the collision load during an offset frontal collision is input to the second crash box as well as the first crash box, and the resulting rotational displacement of the second crash box is transmitted to the first crash box via the bumper force side.

[0012] In another aspect, each of the second crash boxes may have a shape that opens outwardly in the vehicle width direction toward the front.

[0013] Therefore, since the second crash box has a shape that opens outward toward the front and toward the outside of the vehicle width, even a collision further outward in the vehicle width can be absorbed by the second crash box, and rotational force is more likely to be generated when a collision load is input.

[0014] In another aspect, an outer surface of a front region of a base of each of the front suspension members may be shaped to extend forward and outward in the vehicle width direction.

[0015] Therefore, when the first crash box rotates and displaces, the angle between its outer surface and the outer surface of the front region of the base of the front suspension member gradually decreases, and the collision load is transmitted from the first crash box to the front end of the front suspension member with the outer surfaces of the first crash box and the front suspension member in a state where they are substantially aligned, so that the collision load can be efficiently used to bend and deform the front suspension member.

[0020] In another aspect, the outer fastening portion may be disposed on the vehicle widthwise inner side of outer ends of the front suspension member and the base of the first crash box.

[0021] Therefore, the outer end portion can be bent and deformed without being hindered by the outer fastening portion, and even if the outer end portion is bent and deformed, the outer fastening portion is unlikely to be affected.

[0022] As another aspect, a power plant of the vehicle may be disposed adjacent to the front suspension member on the vehicle width inner side.

[0023] Therefore, the front suspension member is bent and deformed by the collision load transmitted from the first crash box, and one side of the front suspension member interferes with and presses against the power plant, making the vehicle body more likely to slip sideways. Effect of the Invention

[0024] According to the vehicle front structure of the present invention, the crash boxes can be effectively utilized to reduce the amount of vehicle body deformation during an offset frontal collision. [Brief description of the drawings]

[0025] [Figure 1] 1 is a perspective view of a front structure of a vehicle according to an embodiment, as viewed diagonally from the front left. [Diagram 2] FIG. 2 is a perspective view of the front structure of the vehicle as viewed diagonally from the rear left. [Diagram 3] FIG. 2 is a bottom view of the vehicle body including the left front suspension member and the lower crash box. [Figure 4] 4 is an explanatory view corresponding to FIG. 3, showing the left front side member and the upper crash box as viewed from below. FIG. [Diagram 5] 3 is a cross-sectional view taken along line VV in FIG. 2, illustrating the arrangement of inner and outer fastening portions relative to the outer surfaces of the left front suspension member and the lower crash box. FIG. [Figure 6] 6 is a schematic view showing a flange portion that is not deformed under normal conditions, corresponding to the view taken along an arrow A in FIG. 5. [Figure 7] FIG. 11 is a side view showing the deformation state of a front suspension member and a lower crash box during a small overlap frontal collision. [Figure 8] FIG. 4 is a bottom view corresponding to FIG. 3 and illustrating a deformation state of a front suspension member and a lower crash box during a small overlap frontal collision. [Figure 9] 7 is a schematic diagram corresponding to FIG. 6 and showing a deformation state of a flange portion at the time of a minute lap front collision. FIG. [Figure 10] FIG. 11 is a diagram showing test results comparing the occurrence of vehicle body lateral deviation in a slight overlap frontal collision between an embodiment and a conventional example. [Figure 11] FIG. 13 is a diagram showing test results comparing the amount of collision energy absorbed in a small overlap frontal collision between the embodiment and a conventional example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a vehicle front structure embodying the present invention will now be described. Fig. 1 is a perspective view of the front structure of a vehicle according to this embodiment, as seen diagonally from the front left, Fig. 2 is a perspective view as seen diagonally from the rear left, Fig. 3 is a bottom view of a vehicle body including a left-side front suspension member and a lower crash box, and Fig. 4 is an explanatory diagram corresponding to Fig. 3, as seen from below of a left-side front side member and an upper crash box. In the following explanation, front-rear, left-right, and up-down directions are expressed based on the driver in the vehicle. Also, each figure mainly shows the configuration of the left side, but the right side has the same configuration, which is symmetrical.

[0027] A pair of left and right front side members 1 (only the left one is shown) are arranged as frame members constituting the vehicle body, and an engine room 3 is defined between the two front side members 1, accommodating a power plant 2 (shown in FIG. 3) consisting of a motor, a reducer, etc. An upper crash box 4 (corresponding to the "second crash box" of the present invention) is arranged on the front side of each front side member 1, and flanges 1a, 4a are welded to the front end of each front side member 1 and the rear end of each upper crash box 4, respectively, and the four corners are fastened to each other by bolts 5 and nuts (not shown). A bumper force upper 6 is spanned across the front sides of the left and right upper crash boxes 4, and both left and right ends of the bumper force upper 6 are welded to each upper crash box 4. As a result, both left and right ends of the bumper force upper 6 are connected to the front end of the front side member 1 via the upper crash box 4.

[0028] The upper crash box 4 of this embodiment has a rectangular cross section and is shaped to open forward in plan view. In more detail, taking the left upper crash box 4 shown in FIG. 4 as an example, the right side (inner side) of the upper crash box 4 is formed along the right side (inner side) of the front side member 1 extending in the front-rear direction as shown by the solid line in the figure. In contrast, the left side (outer side) of the upper crash box 4 is formed to form an angle α with the left side (outer side) of the front side member 1 extending in the front-rear direction. As a result, the left upper crash box 4 is shaped to open leftward toward the front, in other words, its left side bulges leftward from the left side of the front side member 1. Although not shown or described, the right upper crash box 4 also has the same shape that is symmetrical to the left.

[0029] Such a shape of the upper crash box 4 is designed with a small overlap frontal collision of the vehicle in mind. That is, by making the upper crash box 4 bulge outward in the width direction of the vehicle, the intention is to input as much of the impact load as possible to the upper crash box 4 even when the impact load is from the outside of the vehicle width, and to cause the upper crash box 4 to rotate and displace.

[0030] A pair of left and right front suspension members 7 (only the left one is shown) are disposed below the left and right front side members 1, and the front portions of these front suspension members 7 are connected to each other via a front cross member 8 and their rear portions are connected to each other via a rear cross member (not shown). This forms a subframe 9, which supports the left and right front suspensions (not shown). The left and right front suspension members 7 are disposed on either side of the power plant 2, and as shown in FIG. 3, a gap S is formed in the vehicle width direction between the left front suspension member 7 and the power plant 2. Although not shown, the same gap S is also formed between the right front suspension member 7 and the power plant 2.

[0031] On the front sides of the left and right front suspension members 7, lower crash boxes 10 (corresponding to the "first crash boxes" of the present invention) are respectively disposed. The left and right front side members 1, the left and right front suspension members 7 are disposed at substantially the same positions in the vehicle width direction (positions overlapping in top view). Further, the left and right upper crash boxes 4 and the left and right lower crash boxes 10 are disposed at substantially the same positions in the vehicle width direction (positions overlapping in top view).

[0032] Each front suspension member 7 is composed of a cylindrical main body portion 7c and a plate-shaped flange portion 7a. The main body portion 7c extends in the front-rear direction, and the flange portion 7a is welded to the front end thereof and extends outward from the front end. Each lower crash box 10 is composed of a cylindrical main body portion 10f and a plate-shaped flange portion 10a. The main body portion 10f extends in the front-rear direction, and the flange portion 10a is welded to the rear end thereof and extends outward from the rear end. The flange portions 7a and 10f are overlapped and fastened to each other by fastening portions 13in and 13out composed of bolts 11 and nuts 12.

[0033] A bumper force lower 14 is bridged over the front sides of the main body portions 10f of the left and right lower crash boxes 10, and this bumper force lower 14 is located below the bumper force upper 6. Both left and right ends of the bumper force lower 14 are welded to the main body portions 10f of the respective lower crash boxes 10, whereby both left and right ends of the bumper force lower 14 are respectively connected to the front ends of the main body portions 7c of the front suspension members 7 via the main body portions 10f of the lower crash boxes 10.

[0034] As shown in FIG. 3, the outer side surface 7b of the front region of the main body portion 7c of the left and right front suspension members 7 extends substantially linearly forward and toward the vehicle width outside in a plan view. Such a shape of the main body portion 7c of the front suspension member 7 is designed to assume a small-lap frontal collision of the vehicle, and is designed to input as much as possible into the main body portion 10f of the lower crash box 10 even in the case of a collision of another vehicle or an obstacle (hereinafter collectively referred to as a collision object D) toward the vehicle width outside. This prevents the collision object D from slipping backward along the vehicle width outside of the front suspension member 7, and thus prevents the collision load from the collision object D from being input to the side sill side through the front wheel. An angle β is formed between the inclined outer side surface 7b of the main body portion 7c of the front suspension member 7 and the outer side surface 10b of the main body portion 10f of the lower crash box 10 extending in the front-rear direction, as shown in FIG. 3.

[0035] 1, a bumper force side 15 is provided on each of the left and right sides of the vehicle body, and the upper part of each bumper force side 15 is fastened by bolts and nuts to the bumper force upper 6 and the lower part is fastened by bolts and nuts to the bumper force lower 14. As a result, the front end of the upper crash box 4 and the front end of the lower crash box 10 are connected via the bumper force side 15 on each of the left and right sides of the vehicle body.

[0036] Fig. 5 is a cross-sectional view taken along line VV in Fig. 2, showing the arrangement of the inner and outer fastening parts relative to the outer surfaces of the left front suspension member 7 and the lower crash box 10, and Fig. 6 is a schematic view corresponding to the arrow A in Fig. 5, showing the flange parts 7a, 10a that are not deformed under normal conditions. Below, the connection structure between the front suspension member 7 and the lower crash box 10 via the flange parts 7a, 10a will be described in more detail with reference to these drawings.

[0037] In short, the flange portions 7a, 10a are fastened to each other at two points on a line L near the diagonal by fastening portions 13in, 13out, and these fastening portions 13in, 13out are positioned at a distance from the outer surface of the main body portion 7c of the front suspension member 7 and the outer surface of the main body portion 10f of the lower crash box 10.

[0038] 1 and 5, the main body portion 10f of the lower crash box 10 has a rectangular cross section and extends in the front-to-rear direction, and the front end of the main body portion 7c of the front suspension member 7 also has the same cross section as the main body portion 10f of the lower crash box 10, and both members 7c, 10f are connected in the front-to-rear direction via flange portions 7a, 10a. Hereinafter, of the connection points having a rectangular cross section, the connection point corresponding to the inner side of the vehicle width is referred to as the inner end portion 16in, and the connection point corresponding to the outer side of the vehicle width is referred to as the outer end portion 16out.

[0039] 5 as an example, one fastening portion (hereinafter referred to as the inner fastening portion 13in) is spaced upward by a dimension C from an upper surface 10c of a main body portion 10f of the lower crash box 10 (also an upper surface of the main body portion 7c of the front suspension member 7 having the same cross-sectional shape, and the same applies below) and is disposed slightly to the left (outside the vehicle width) of an inner side surface 10d of the main body portion 10f of the lower crash box 10. The other fastening portion (hereinafter referred to as the outer fastening portion 13out) is spaced downward by a dimension C from a lower surface 10e of the main body portion 10f of the lower crash box 10 and is disposed slightly to the right (inside the vehicle width) of an outer side surface 10b of the main body portion 10f of the lower crash box 10. The upper surface 10c of the main body portion 10f of the lower crash box 10, from which the inner fastening portions 13in are spaced apart, corresponds to the "outer surface of the base of the first crash box" of the present invention, and the upper surface of the main body portion 7c of the front suspension member 7 corresponds to the "outer surface of the base of the front suspension member" of the present invention.

[0040] As a result, the line L connecting the two fastening parts 13in, 13out crosses the cross section of the main body part 10f of the lower crash box 10 diagonally, and the fastening parts 13in, 13out are arranged diagonally. By fastening diagonally in this manner, the flange parts 7a, 10a are reliably overlapped as in the case of fastening at the four corners. As a result, the main body part 10f of the lower crash box 10 can be fixed and supported in a desired position relative to the front end of the main body part 7c of the front suspension member 7, and the manufacturing cost can be reduced by reducing the number of fastening parts 13in, 13out. Although not shown or described, the connection part between the right front suspension member 7 and the lower crash box 10 also has the same shape that is symmetrical on the left and right.

[0041] Although the details will be described later, the above-mentioned arrangement of the fastening parts 13in, 13out is intended to actively deform the flange parts 7a, 10a during a small lap front collision. Therefore, in this embodiment, in order to further promote the deformation of the flange parts 7a, 10a, the thickness of the flange parts 7a, 10a is made smaller than the thickness applied to a general flange part. However, the setting of the thickness of the flange parts 7a, 10a is not limited to this and can be changed arbitrarily.

[0042] In addition, the arrangement of the inner fastening portion 13in and the outer fastening portion 13out relative to the outer surface of the main body portion 10f of the lower crash box 10 is not limited to the above. For example, different dimensions C may be applied to the inner fastening portion 13in and the outer fastening portion 13out. The inner fastening portion 13in may be arranged at a position lower than the upper surface 10c of the main body portion 10f of the lower crash box 10 and spaced to the right (inner side of the vehicle width) from the inner surface 10d of the main body portion 10f of the lower crash box 10. Furthermore, the outer fastening portion 13out may be arranged near the outer surface of the main body portion 10f of the lower crash box 10 without being spaced from the outer surface.

[0043] Next, the operation of the front structure configured as above during a slight overlap frontal collision of a vehicle will be described. Fig. 7 is a side view showing the deformation state of the front suspension member 7 and the lower crash box 10 in a slight overlap frontal collision, Fig. 8 is a bottom view corresponding to Fig. 3 showing the deformation state, and Fig. 9 is a schematic diagram corresponding to Fig. 6 showing the deformation state of the flange portions 7a, 10a. Note that the following description will be given for a slight overlap frontal collision occurring on the left side of the vehicle body, but the same applies to a slight overlap frontal collision on the right side.

[0044] When a slight overlap frontal collision occurs to the left side of the vehicle body, the colliding object D collides with the left side portion of the left upper crash box 4 and the left side portion of the main body portion 10f of the lower crash box 10 via the upper and lower bumper reinforcements 6, 14, as shown by the two-dot chain lines in Figures 3 and 4. As a result, the collision load is input to the left side portion of the front end of the upper crash box 4, and also to the left side portion of the front end of the main body portion 10f of the lower crash box 10. The upper crash box 4 has a shape that opens leftward toward the front, and its front end bulges leftward. Therefore, even if the collision occurs further to the left (small overlap amount), the colliding object D is received by the upper crash box 4 and is prevented from passing backward.

[0045] In the early stage of a frontal collision, the upper crash box 4, which has four corners of the flanges 1a and 4a fastened, transmits the collision load to the front side member 1 without collapsing. In contrast, the main body portion 10f of the lower crash box 10 has only two fastening points, but its front end is restrained from the upper crash box 4 side via the bumper force side 15. If the bumper force side 15 were not present, the front end of the main body portion 10f of the lower crash box 10 would collapse downward in side view, as shown by the two-dot chain line in FIG. 7. However, since this phenomenon is prevented by the bumper force side 15, the main body portion 10f of the lower crash box 10 also does not collapse, but instead transmits the collision load to the front suspension member 7 while absorbing it, as shown by the solid line in FIG. 7. This improves the strength in the fore-and-aft direction of the vehicle body, thereby reducing the amount of deformation of the vehicle body.

[0046] As the frontal collision progresses further, the upper crash box 4 is gradually crushed by the collision load and rotates from the position shown by the solid line in Fig. 4 to a position in which the front end has moved to the left, as shown by the two-dot chain line. Since the upper crash box 4 has a shape that opens to the left, a rotational force is easily generated, and the rotational displacement thus generated is efficiently transmitted to the main body portion 10f of the lower crash box 10 via the bumper force side 15.

[0047] The main body portion 10f of the lower crash box 10 itself generates a rotational force due to the input of the collision load from the colliding object D to its left side portion, but this may not be enough to cause a rotational displacement. However, because the rotational force is transmitted from the upper crash box 4 via the bumper force side 15, the main body portion 10f of the lower crash box 10 also undergoes rotational displacement in the same direction as the upper crash box 4, that is, so that the front end moves leftward, as shown by the arrow in Figure 8. At this time, the main body portion 10f of the lower crash box 10 undergoes rotational displacement around the outer end portion 16out, and accordingly, the flange portions 7a, 10a at the outer end portion 16out are bent and deformed, and the inner ends 16in are separated from each other.

[0048] The rotational displacement of the main body portion 10f of the lower crash box 10 is permitted by the connection structure via the flange portions 7a, 10a as described above. More specifically, since each fastening portion 13in, 13out is separated from the upper surface 10c and the lower surface 10e of the main body portion 10f of the lower crash box 10 by a dimension C, the area of ​​the flange portions 7a, 10a corresponding thereto can be deformed while maintaining fastening by the fastening portions 13in, 13out. Therefore, even if the inner ends 16in are separated from each other due to the rotational displacement of the main body portion 10f of the lower crash box 10, the area of ​​the flange portions 7a, 10a between the upper surface 10c of the main body portion 10f of the lower crash box 10 and the inner fastening portion 13in is deformed as shown in FIG. 9, and thus the separation of the inner ends 16in is permitted without damaging the inner fastening portion 13in.

[0049] Furthermore, even if the flange portions 7a, 10a are bent and deformed at the outer end portion 16out due to the rotational displacement of the main body portion 10f of the lower crash box 10, the effect is gradually reduced in the region of the flange portions 7a, 10a between the lower surface 10e of the main body portion 10f of the lower crash box 10 and the outer fastening portion 13out. Therefore, the bending and deformation of the flange portions 7a, 10a at the outer end portion 16out is permitted without damaging the outer fastening portion 13out.

[0050] Particularly in this embodiment, the outer fastening portion 13out is disposed slightly to the right of the outer surface 10b of the main body portion 10f of the lower crash box 10, in other words, at a position offset to the right from an extension line of the outer end portion 16out, as shown in Fig. 5. This reduces the mutual influence between the fastening by the outer fastening portion 13out and the bending deformation of the flange portions 7a, 10a at the outer end portion 16out.

[0051] That is, the flanges 7a, 10a are bent and deformed without being hindered by the outer fastening portion 13out, and even if the flanges 7a, 10a are bent and deformed, the outer fastening portion 13out is unlikely to be affected. As a result, it is possible to more reliably prevent damage to the outer fastening portion 13out and to more reliably achieve the bending and deformation of the flanges 7a, 10a at the outer end 16out. In addition, according to the arrangement of the outer fastening portion 13out shown in FIG. 5, the outer fastening portion 13out is sufficiently separated from the inner fastening portion 13in, so that the flanges 7a, 10a can be more reliably overlapped with each other even with only two fastening portions 13in, 13out.

[0052] The main body portion 10f of the lower crash box 10 thus rotated and displaced is pinched between the colliding object D and the vehicle body as shown in FIG. 8. At this point, the main body portion 10f of the lower crash box 10 has not yet been crushed, so it is in a state of tension between the colliding object D and the front end of the main body portion 7c of the front suspension member 7, and transmits the collision load input from the colliding object D to the front end of the main body portion 7c of the front suspension member 7. In response to this collision load, the main body portion 7c of the front suspension member 7 is bent rightward and one side of the main body portion 7c of the front suspension member 7 interferes with and presses the power plant 2 from the left while narrowing the gap S. As a result, the collision load from the colliding object D is transmitted to the vehicle body via the main body portion 10f of the lower crash box 10, the main body portion 7c of the front suspension member 7, and the power plant 2, causing a lateral displacement that moves the entire vehicle body rightward. At the same time, the upper and lower crash boxes 10 undergo crushing, absorbing the collision load and transmitting it to the front side member 1 and the front suspension member 7, thereby improving the longitudinal strength of the vehicle body and contributing to reducing the amount of deformation of the vehicle body.

[0053] As shown in FIG. 3, the outer surface 7b of the front region of the main body portion 7c of the front suspension member 7 extends in a substantially straight line toward the front and the vehicle width outside in order to prevent the collision object D from passing through during a small overlap frontal collision, and this shape is also suitable for bending and deforming the main body portion 7c of the front suspension member 7. That is, when the main body portion 10f of the lower crash box 10 is rotated and displaced, the angle β between the outer surface 10b and the outer surface 7b of the main body portion 7c of the front suspension member 7 gradually decreases, and as shown in FIG. 8, the outer surfaces 7b, 10b of the main body portion 7c of the front suspension member 7 become substantially linear. In this positional relationship, the collision load is transmitted from the main body portion 10f of the lower crash box 10 to the front end of the main body portion 7c of the front suspension member 7, so that the collision load can be efficiently used for bending and deforming the main body portion 7c of the front suspension member 7. Therefore, the amount of lateral deviation of the vehicle body can be increased, and the vehicle passing effect can be further improved.

[0054] FIG. 10 is a diagram showing a test result comparing the occurrence of the amount of lateral deviation of the vehicle body in a small overlap frontal collision between the embodiment and a conventional example (equipped with general upper and lower crash boxes). In a small overlap frontal collision, the vehicle body does not receive the collision load head-on as in a full overlap frontal collision, but rather undergoes lateral deviation in a direction to secure a gap with the collision object D, and thus deflects part of the collision load, thereby generating a so-called vehicle body passing effect. The lateral deviation occurring in the vehicle body at this time can be considered to be correlated with the strength of the vehicle body passing effect. As shown in the figure, when a small overlap collision occurs, the amount of lateral deviation of the vehicle body gradually increases in both the embodiment and the conventional example. In this embodiment, the main body portion 7c of the front suspension member 7 is bent and deformed due to the rotational displacement of the main body portion 10f of the lower crash box 10, and interferes with the power plant 2. Therefore, the amount of lateral deviation of the vehicle body increases more rapidly than in the conventional example, and a stronger vehicle body passing effect is obtained.

[0055] 11 is a diagram showing the test results comparing the amount of energy absorbed in the embodiment and the conventional example during a small overlap frontal collision. It can be seen that the amount of energy absorbed by the engine room 3 is greater in this embodiment than in the conventional example. The main reason for this is that the lower crash boxes 10, which are restrained by the bumper force side 15 and prevented from collapsing, perform the expected function of absorbing the collision load and transmitting it to the front suspension member 7.

[0056] In addition, in this embodiment, the overall amount of energy absorption is reduced compared to the conventional example, and the main reason for this is the improvement in the vehicle body passing effect as described above. Therefore, in combination with the increase in the amount of energy absorption in the engine room 3, the amount of energy absorption in the cabin can be significantly reduced. This makes it possible to reduce the amount of deformation of the vehicle body, particularly the amount of deformation of the cabin, in a slight overlap frontal collision.

[0057] Although the above has been described in relation to a small overlap frontal collision, even in a typical offset frontal collision with a larger amount of overlap (e.g., 50%), the same process occurs, causing the crushing of each crash box 4, 10 and the transmission of collision load, and the resulting effects are also the same.

[0058] In addition, as described above, the main body portion 10f of the lower crash box 10 is prevented from collapsing by the restraint via the bumper force side 15, and therefore, although details will not be described, in the event of a full-wrap collision, the same effect as that of a general front structure can be obtained.

[0059] Although the description of the embodiment is finished above, the aspect of the present invention is not limited to this embodiment. For example, the number and arrangement of the fastening parts 13in, 13out on the flange parts 7a, 10a may be changed, the bumper force side 15 may be omitted, and the shapes of each crash box 4, 10, the front side member 1, the front suspension member 7, etc. may be changed. [Explanation of symbols]

[0060] 1 Front side member 4 Upper crash box (second crash box) 7. Front suspension member 7a Flange 7c Main body part (base) 9 Subframe 10 Lower crash box (first crash box) 10a Flange part 10c Top surface (outside surface) 10e Bottom surface (outside surface) 10f Main body part (base) 13in inner fastening 13out Outer fastening part 15 Bumper Force Side

Claims

1. A pair of left and right front suspension members constituting a subframe of the vehicle body; a pair of left and right first crash boxes respectively connected to front ends of the front suspension members, each of the first crash boxes is connected to the front suspension member such that a front portion of the first crash box is rotated and displaced outward in a vehicle width direction when a collision load is input to the vehicle body due to an offset frontal collision; each of the front suspension members and each of the first crash boxes includes a base portion extending in the front-rear direction of the vehicle body and a flange portion extending outward from an end of the base portion; the flange portions of each of the front suspension members and each of the first crash boxes are overlapped with each other and fastened to each other by a plurality of fastening portions, Each fastening portion includes at least an inner fastening portion located on a vehicle width inner side and an outer fastening portion located on a vehicle width outer side, the inner fastening portion is spaced apart from an outer surface of a base of the front suspension member and an outer surface of a base of the first crash box; The inner fastening portion and the outer fastening portion are disposed at only two diagonal positions of a cross section of the first crash box. A front structure of a vehicle.

2. a pair of left and right front side members disposed above each of the front suspension members; a pair of left and right second crash boxes respectively connected to front ends of the front side members; A pair of left and right bumper force sides connecting a front end of the first crash box and a front end of the second crash box on both left and right sides of the vehicle body, The front structure of a vehicle according to claim 1, further comprising:

3. Each of the second crash boxes is formed in a shape that is expanded outwardly in the width direction of the vehicle toward the front.

3. The vehicle front structure according to claim 2.

4. The outer surface of the front region of the base of each of the front suspension members is shaped to extend forward and outward in the vehicle width direction.

4. The vehicle front structure according to claim 2 or 3.

5. (delete)

6. (delete)

7. The outer fastening portion is disposed on the vehicle widthwise inner side of outer ends of the front suspension member and the base of the first crash box.

2. The vehicle front structure according to claim 1.

8. A power plant of the vehicle is disposed adjacent to the front suspension member on the vehicle width inner side.

8. A vehicle front structure according to claim 1, wherein the vehicle front structure is a front structure of a vehicle.

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