JP7550105B2 - Front body structure - Google Patents

Description

The present invention relates to a vehicle front structure that absorbs collision energy using front side frames on both sides of the vehicle body.

For example, Patent Document 1 describes a vehicle front structure in which a front side frame (also called a side frame) absorbs collision energy. This vehicle front structure reinforces the side frame by overlapping and joining stiffeners with a U-shaped cross section to the side surface rearward of a position spaced a specified distance from the front end of the side frame. This structure makes it possible to absorb impact energy by deforming the side frame body together with the stiffener, even in the case of a so-called micro-lap collision, in which the impact occurs at a position outside the axis of the side frame body.

Patent No. 4783761

In the structure of Patent Document 1, the front portion of the side frame, from the front end of the side frame to the front end of the stiffener, which is a predetermined distance away, is structured only with the side frame plate without any stiffener. For this reason, if a small-lap collision occurs at the front portion of the side frame, the collision energy may cause the front portion of the side frame to deform significantly in the vehicle width direction. If the front portion of the frame deforms significantly, the deformation of the stiffener joint becomes small, and the collision energy cannot be sufficiently absorbed.

The present invention was made in consideration of these circumstances, and aims to provide a vehicle front structure that can absorb collision energy during a small overlap collision without significantly deforming the front portion of the front side frame.

In order to achieve the above-mentioned object, the front body structure of the present invention comprises a hollow front side frame extending in the fore-and-aft direction, a first reinforcing plate with an L-shaped cross-sectional shape arranged inside the front side frame, and a second reinforcing plate arranged inside the front side frame forward of the first reinforcing plate, wherein the front side frame has a ridge line extending in the fore-and-aft direction, the first reinforcing plate is arranged so that the ridge line of the L-shaped cross-sectional shape overlaps the ridge line of the front side frame, and the second reinforcing plate is offset more toward the outside in the vehicle width direction than its rear end side, and is joined in a state where the front end of the first reinforcing plate joined to the lower side within the C-shaped cross section of the front side frame and the rear end of the second reinforcing plate are abutting and aligned .

The present invention provides a front body structure that can absorb collision energy during a small overlap collision without causing significant deformation of the front portion of the front side frame.

1 is a side view of a front side frame as a vehicle front body structure according to an embodiment of the present invention, the front side frame being on an outer side in a vehicle width direction. 1 is a perspective view showing a plurality of first reinforcing plates having an L-shaped cross section arranged within a U-shaped cross section of a front side frame; FIG. FIG. 2 is a perspective view showing a plurality of first reinforcing plates having an L-shaped cross section and first and second bulkheads arranged within the U-shaped cross section of the front side frame. FIG. 4 is a cross-sectional view taken along line IV-IV of FIG. 1 is a side view of a vehicle body front structure of an automobile according to an embodiment of the present invention. 6 is a perspective view showing a structure as viewed from an obliquely forward side of the vehicle body indicated by an arrow IV in FIG. 5 toward the front side of the vehicle body. FIG. 7 is a perspective view showing the structure when the connecting plate shown in FIG. 6 is removed. FIG. 4 is a cross-sectional view taken along line IV-IV of FIG. 6 is a cross-sectional view taken along the line VV in FIG. 5 as viewed from above. FIG. 4 is a plan view showing three bending points of the front side frame. FIG. 2 is a perspective view showing a bumper beam extension. 11 is a side view showing a state in which the front side frame is bent upward. FIG. FIG. 2 is a perspective view showing a bulkhead coupled to a front side frame. This is a cross-sectional view taken along line XIV-XIV of Figure 13.

<Configuration of the embodiment>
An embodiment of the present invention will be described in detail with reference to Figures 1 to 14. In the description, the same elements are given the same reference numerals, and duplicated description will be omitted. In each figure, the arrows "front and rear" indicate the front and rear directions of an automobile (not shown), "left and right" indicate the width direction of the automobile, and "up and down" indicate the vertical up and down directions.

Figure 1 is a side view of the vehicle width direction outer side of a front side frame 11 (frame 11) as a vehicle body front structure of an automobile according to this embodiment. Figure 2 is a perspective view showing a plurality of first reinforcing plates 21a, 21b, 21c with an L-shaped cross section arranged within the U-shaped cross section of frame 11. Figure 3 is a side view showing a plurality of first reinforcing plates 21a, 21b, 21c with an L-shaped cross section arranged within the U-shaped cross section of frame 11, as well as a first bulkhead 25a and a second bulkhead 25b. Figure 4 is a cross-sectional view taken along line IV-IV in Figure 3.

As shown in FIG. 1, the vehicle body front structure 10 has a U-shaped cross section that opens to the outside in the vehicle width direction (also simply referred to as the outside) of the frame 11 that extends linearly on both sides of the vehicle body, and a first reinforcing plate 21 and a second reinforcing plate 22 (see FIG. 7) are joined in this order from the rear side of the vehicle body to the front end. The first reinforcing plate 21 is a stiffener that reinforces the rear side of the frame 11, and the second reinforcing plate 22 reinforces the front side of the frame 11.

The second reinforcing plate 22 on the front side of the vehicle body is curved outward (offset) from the rear end side 22b toward the front end side (see Figure 9), and has a U-shape in cross section.

The first reinforcing plate 21 is composed of multiple first reinforcing plates 21a, 21b, and 21c. The first reinforcing plate 21a is joined to the lower side of the U-shaped cross section of the frame 11, and is joined in a state in which the front end of the first reinforcing plate 21a and the rear end of the second reinforcing plate 22 are in contact and aligned. The first reinforcing plates 21b and 21c are joined to the upper side of the U-shaped cross section of the frame 11.

The lower first reinforcing plate 21a has an L-shaped cross section as shown in FIG. 2, and is joined to the ridge line 11j1 formed by the corner where the vertical and horizontal faces on the lower side of the U-shaped cross section of the frame 11 meet, with the ridge line formed by the lower corner of the L-shaped cross section of the first reinforcing plate 21a aligned with the ridge line.

The upper first reinforcing plates 21b, 21c have an L-shaped cross section as shown in FIG. 3, and as shown in FIG. 4 as a representative example of the first reinforcing plate 21b, the ridge line 11j2 formed by the upper corner of the L-shaped cross section of the first reinforcing plate 21b is joined to the ridge line 11j2 formed by the upper corner of the U-shaped cross section of the frame 11.

As shown in Figs. 1 to 4, the hollow portion of the frame 11 is provided with a wall-like first bulkhead 25a and second bulkhead 25b that divide the hollow portion into front and rear portions. The first bulkhead 25a and second bulkhead 25b have flanges on the top, bottom, left and right, and the flanges are joined to the top, bottom and left and right surfaces of the frame 11. The first bulkhead 25a is provided across the rear end of the upper first reinforcing plate 21b and the middle part of the lower first reinforcing plate 21a. The second bulkhead 25b is provided across the middle part of the upper first reinforcing plate 21c and the rear end of the lower first reinforcing plate 21a. As shown in Fig. 4, the opening of the frame 11 is closed by a back plate 15, which will be described later.

Next, Figure 5 is a side view of the frame 11 on the inner side in the vehicle width direction. Figure 6 is a perspective view showing the structure as viewed from the diagonally forward side of the vehicle body indicated by the arrow VI in Figure 5 toward the front side of the vehicle body. Figure 7 is a perspective view showing the structure when the connecting plate 16 shown in Figure 6 is removed. Figure 8 is a cross-sectional view taken along line VIII-VIII in Figure 5. Figure 9 is a cross-sectional view taken along line IX-IX in Figure 5 as viewed from above.

As shown in FIG. 5, the vehicle front structure 10 includes upper members 12 that extend outward from the frames 11 on both sides. The upper members 12 are curved in an arch shape from above the tires (not shown) to the front part of the vehicle body, and as shown in FIG. 7, the front end side of the upper members 12 on the vehicle body is disposed adjacent to the front end side of the frames 11.

The frame 11 shown in FIG. 5 has a so-called hat-shaped cross-sectional shape on the rear side. Specifically, the rear side of the frame 11 has a U-shaped cross-sectional portion 11c that has a roughly U-shaped cross-sectional shape (see FIG. 8), and flanges 11a, 11b that extend vertically from the open end of the U-shaped cross-sectional portion 11c. On the other hand, the front side of the frame 11, as shown in FIG. 7, has an expanded U-shaped cross-sectional portion 11e that continues from the U-shaped cross-sectional portion 11c and expands in the vehicle width direction and vertical direction. The U-shaped cross-sectional portion 11c and the expanded U-shaped cross-sectional portion 11e correspond to the "frame body" in the claims.

The U-shaped cross-sectional expansion portion 11e does not have flanges 11a, 11b like the U-shaped cross-sectional portion 11c, and is provided with an upper wall 11e1, an inner wall 11e2 on the inside in the vehicle width direction (also simply referred to as the inside), an inclined wall 11e3 that inclines downward from the inner wall 11e2 to the outside, and an outer wall 11e4 made of a back plate 15 (see Figure 11) that closes the outer openings of both the U-shaped cross-sectional expansion portion 11e and the U-shaped cross-sectional portion 11c. Both the U-shaped cross-sectional expansion portion 11e and the U-shaped cross-sectional portion 11c constitute the frame body described in the claims.

The frame 11 has a hollow frame shape extending in the vehicle body fore-and-aft direction (also called the front-and-rear direction) due to the blocking of the opening by the back plate 15. Furthermore, the front end of the U-shaped cross-sectional enlarged portion 11e of the frame 11 and the front end of the upper member 12 are connected by a connecting plate 16 as shown in FIG. 6.

In addition, a second reinforcing plate 22 is fixed inside the hollow frame-shaped U-shaped cross-section expansion portion 11e shown in Figure 7, and extends vertically along the fore-and-aft direction of the vehicle body so as to divide the interior into left and right parts in the vehicle width direction.

The second reinforcing plate 22 extends rearward along the outer wall 11e4 within the frame 11 while being spaced apart from the outer wall 11e4, and as shown in FIG. 1, its extending rear end 22b is joined within the U-shaped cross section. The rear end 22b is joined in a state where this end is located at the bending point 11n of the frame 11 shown by the dashed line, and abuts against the front end of the first reinforcing plate 21.

As shown in FIG. 9, the second reinforcing plate 22 is inclined outward in the vehicle width direction from the inner wall of the U-shaped cross-section portion 11c toward the front end of the enlarged U-shaped cross-section portion 11e, and forms a closed cross-section 11k that continues into the hollow portion between the back plate 15.

The lower end 22a of the second reinforcing plate 22 is connected to the lower end of the outer wall 11e4 of the frame 11, as shown in FIG. 7. This connection gives the U-shaped cross-sectional expansion portion 11e on the front side of the frame 11 a large cross-sectional shape that extends vertically.

As shown in FIG. 5, the U-shaped cross-sectional expansion portion 11e has a trumpet shape that gradually opens up and down from the rear side of the frame 11 toward the front end. More specifically, the upper surface of the frame 11 extends forward and backward at a substantially constant height, and the lower surface of the frame 11 slopes downward toward the front end. Along this trumpet shape that opens up and down, as shown in FIG. 7, a second reinforcing plate 22 is disposed within the frame 11. With this configuration, in the event of a collision with another vehicle, the load input (arrow Y1) is smoothly transmitted through the trumpet shape reinforced by the second reinforcing plate 22 to the U-shaped cross-sectional portion 11c on the rear side of the frame 11.

Furthermore, as shown in FIG. 9, the U-shaped cross-sectional expansion portion 11e has a trumpet shape that gradually opens outward from the rear side of the frame 11 toward the front end. More specifically, the inner surface of the frame 11 extends straight in the front-rear direction, and the outer surface of the frame 11 is inclined so that it is positioned more outward in the vehicle width as it approaches the front end. A second reinforcing plate 22 is disposed within the frame 11 along this outwardly opening trumpet shape. With this configuration, when a slight overlap collision occurs with the upper member 12 with an opposing vehicle, the diagonal load input due to the collision is smoothly transmitted through the trumpet shape reinforced by the second reinforcing plate 22, and is transmitted in a concentrated manner toward the bending points 11g, 11h, and 11i (FIG. 10) on the rear side of the frame 11.

As shown in the plan view of the frame 11 from above in FIG. 10, the U-shaped cross section 11c of the frame 11 has at least three bending points 11g, 11h, and 11i in the front-rear direction of the vehicle body. The bending points 11g, 11h, and 11i are arranged in this order from the front. The bending points 11b and 11i are provided on the outer side of the frame 11, and the bending point 11h is provided on the inner side of the frame 11. Each bending point 11g, 11h, and 11i is a V-shaped valley portion, and a small lap collision load in the direction indicated by the arrow Y2 is transmitted from the second reinforcing plate 22 (FIG. 1) connected inside the frame 11 to the first reinforcing plates 21a, 21b, and 21c (FIG. 1), causing the bending points to bend in a zigzag pattern in the vehicle width direction.

At least one of the first reinforcing plates 21a, 21b, and 21c is disposed along at least one edge line 11j1 or edge line 11j2 of the frame 11 shown in FIG. 4. A bulkhead 25 consisting of a first bulkhead 25a and a second bulkhead 25b is connected to the middle of the first reinforcing plates 21a, 21b, and 21c that extend in the vehicle front-rear direction, spanning both the first reinforcing plates 21a, 21b, and 21c and the U-shaped cross section of the frame 11. The above-mentioned bending points 11h and 11i are formed in the frame 11 as weak parts in the vicinity of these bulkheads 25a and 25b. The weak parts may be beads, holes, etc., other than the bent shapes of the bending points.

In this way, by forming a weak portion near the bulkhead 25 that reinforces the frame 11, the force of a collision is concentrated at the weak portion near the portion reinforced by the bulkhead 25, so that the frame 11 can be reliably folded together with the first reinforcing plates 21a, 21b, and 21c.

As shown by dashed line 11Z in Figure 10, the frame 11 bends in a zigzag shape together with the first reinforcing plates 21a, 21b, and 21c. To explain further, during a collision, the bending point 11g of the U-shaped cross-section portion 11c bends together with the first reinforcing plates 21a and 21b to a position on the inside of the vehicle body in the vehicle width direction as indicated by arrow Yg. Furthermore, the bending point 11h bends together with the first reinforcing plates 21a, 21b, and 21c to a position on the outside of the vehicle body in the vehicle width direction as indicated by arrow Yh, thereby bending in a zigzag shape like the frame 11Z.

In addition to the above, the first reinforcing plates 21a, 21b, 21c may be arranged along at least two ridges 11j1, 11j2 of the frame 11 shown in FIG. 14. A bulkhead 25 consisting of a first bulkhead 25a and a second bulkhead 25b is connected to the first reinforcing plates 21a, 21b, 21c and the U-shaped cross section of the frame 11 in the middle of the first reinforcing plates 21a, 21b, 21c arranged in the vehicle front-rear direction. The above-mentioned bending points 11h, 11i are formed as weak parts of the frame 11 near these bulkheads 25a, 25b.

In this configuration, in the event of a small overlap collision, the first reinforcing plates 21a, 21b, and 21c also break along with the two ridges 11j1 and 11j2 of the frame 11, increasing the amount of collision energy absorbed.

As shown in FIG. 3, the bulkhead 25 includes at least a first bulkhead 25a as an engine mount fastening portion and a second bulkhead 25b as a subframe fastening portion.

The first bulkhead 25a has a cylindrical cavity inside, is open at the top, and is equipped with a bulge 25a1 that bulges outward in the vehicle width direction. A nut 26 is inserted into the cavity from the opening of the bulge 25a1 and is fixed in place. The nut 26 has a cylindrical shape with a screw hole formed inside and a ring portion fixed on top, and the ring portion is exposed and fixed on the bulge 25a1. The engine mount bolt is screwed into the ring portion of the nut 26 to fasten it.

The second bulkhead 25b has a cylindrical cavity inside, an open bottom, and a bulging portion 25b1 that bulges outward. A nut 27 is inserted into the cavity from the opening of the bulging portion 25b1 and fixed in place. The nut 26 is fixed with its annular portion exposed below the bulging portion 25b1. A bolt of the subframe is screwed into the annular portion of the nut 27 to fasten it.

Figure 11 is a perspective view of the frame 11 on the left side of the vehicle body, seen from the right front side. A bumper beam extension (also called an extension) 13, which has a box-shaped appearance cut in the vehicle width direction, is fixed to the front of a connecting plate 16 that connects the front end of the frame 11 and the front end of the upper member 12. The extension 13 is composed of a box-shaped portion 13c, which is partitioned into a cross-section shaped like glasses by a partition wall 13b extending in the vertical direction, fixed in front of a square plate 13a of the same shape as the connecting plate 16, which is fixed to the front of the connecting plate 16.

As shown in FIG. 9, the partition wall 13b is disposed in a position facing the front end of the second reinforcing plate 22, which extends in the vertical direction. Due to this facing state of the two, the collision load of an opposing vehicle or the like from the front of the vehicle body is transmitted from the partition wall 13b of the extension 13 to the second reinforcing plate 22.

The material of the first reinforcing plates 21a, 21b, and 21c shown in FIG. 2 is preferably changed as follows depending on the vehicle weight, i.e., whether the vehicle is light or heavy.

In other words, for a light vehicle body, it is preferable that the first reinforcing plates 21a, 21b, and 21c with an L-shaped cross section have a plate thickness of 1.0 to 2.0 mm and are made of ordinary steel plate with a tensile strength of 270 MPa.

For heavy vehicle bodies, it is preferable that the first reinforcing plates 21a, 21b, and 21c with an L-shaped cross section have a plate thickness of 1.0 to 2.0 mm and are made of high-tensile steel plate with a tensile strength of 440 to 980 MPa.

As shown in FIG. 3, the front end of the lower first reinforcing plate 21a protrudes forward a predetermined length L1 beyond the front end of the upper first reinforcing plate 21b.

As shown in FIG. 12, the frame 11 is joined to the front end of the rear end member 18, which slopes upward from below the floor panel 31. The rear end member 18 is disposed along the underside of the dash lower 32, which rises from below the floor panel 31 and is disposed in front of the instrument panel 33 from which the handle 34 protrudes. In other words, the frame 11 is bent so that it extends horizontally forward above the floor panel 31. For this reason, there is a risk that deformation will occur in which the tip of the frame 11 is lifted upward in a micro-lap collision, as shown by the reference symbol 11A.

However, in a configuration in which the front end of the first reinforcing plate 21a on the lower side of the frame 11 protrudes forward by a predetermined length beyond the front end of the first reinforcing plate 21b on the upper side, deformation of the frame 11 in the form of lift as shown by the symbol 11A during a collision is suppressed.

As shown in FIG. 4, the rear end of the upper first reinforcing plate 21b, 21c and the rear end of the lower first reinforcing plate 21a are arranged at the same position in the vehicle body longitudinal direction and at the third bending point 11i (see FIG. 10). With this configuration, the rearmost bending point 11i of bending points 11g, 11h, 11i is more likely to bend due to the difference in rigidity between the location with and without the first reinforcing plate 21a, 21b, 21c. The upper first reinforcing plate 21b constitutes the upper first reinforcing plate described in the claims. The lower first reinforcing plate 21a constitutes the lower first reinforcing plate described in the claims.

As shown in FIG. 13, the peripheral portion 25a2 of the first bulkhead 25a, which holds the nut 26 in the bulge portion 25a1, is overlapped and joined to the upper and lower first reinforcing plates 21a, 21b arranged within the U-shaped cross section of the frame 11. Furthermore, the first bulkhead 25a has an upper extension portion 25a3 that extends at a predetermined width so as to overlap the upper flange 11a of the frame 11, and a lower extension portion 25a4 that extends at a predetermined width so as to overlap the lower flange 11b of the frame 11.

As shown in Figure 14, which is a cross-sectional view taken along the line XIV-XIV in Figure 13, the upper extension 25a3 and the lower extension 25a4 of the first bulkhead 25a are sandwiched and joined between the upper and lower flanges 11a, 11b of the frame 11 and the back plate 15.

As shown in FIG. 12, the rear end of the frame 11 is joined to the front end of the rear end member 18, which extends from the inclined surface of the dash lower 32 to the underside of the floor panel 31. With this configuration, it is only necessary to create the horizontal straight portion of the frame 11 for multiple different vehicle models, making the mold inexpensive.

Effects of the embodiment
Next, the characteristics and effects of the vehicle body front structure of the present embodiment described above will be described. The vehicle body front structure 10 has a front side frame 11 that is provided on the inner side in the vehicle width direction and extends in the vehicle front-rear direction.

(1) The vehicle body front structure 10 comprises a hollow front side frame 11 extending in the fore-and-aft direction, first reinforcing plates 21a, 21b, 21c with an L-shaped cross section arranged inside the frame 11, and a second reinforcing plate 22 arranged inside the frame 11 forward of the first reinforcing plates 21a to 21c. The frame 11 has a ridgeline extending in the fore-and-aft direction, and the first reinforcing plates 21a to 21c are arranged so that the ridgeline of the L-shaped cross section overlaps the ridgeline of the frame 11. The second reinforcing plate 22 is configured such that the front end side is offset outward in the vehicle width direction from the rear end side, and the rear end side is aligned in the fore-and-aft direction with the front ends of the first reinforcing plates 21a to 21c.

According to this configuration, when a micro-lap collision occurs on the front side of the frame 11, since the second reinforcing plate 22 is disposed on the front side of the frame 11, the micro-lap collision load can be transmitted from the second reinforcing plate 22 to the first reinforcing plates 21a, 21b, and 21c aligned with the second reinforcing plate 22 without causing significant deformation of the front portion of the frame 11. This transmission causes the frame 11 to deform together with the first reinforcing plates 21a, 21b, and 21c, and the collision energy can be absorbed. In other words, the collision energy can be absorbed without causing significant deformation of the front portion of the frame 11 during a micro-lap collision.

(2)
The frame 11 includes a frame body having both a U-shaped cross-sectional portion 11c and an enlarged U-shaped cross-sectional portion 11e, which are U-shaped cross-sectional portions that open outward in the vehicle width direction, and a back plate 15 that closes the opening and forms a hollow portion extending in the vehicle front-rear direction. The second reinforcing plate 22 has a rear end that abuts against the inner wall of the frame body and is inclined outward in the vehicle width direction from the rear end to the front end, forming a closed cross section 11k (FIG. 9) between the frame body and the back plate 15, and the closed cross section 11k is continuous with the hollow portion.

With this configuration, the minute lap collision load is transmitted from the closed cross section 11k at the front of the frame 11 to the rear, promoting deformation of the rear of the frame 11.

(3) A cylindrical bumper beam extension 13 is installed at the front end of the frame 11, and the front end of the second reinforcing plate 22 is positioned so as to overlap in the vehicle width direction with a partition wall 13b that divides the hollow portion of the extension 13 in the vehicle width direction.

With this configuration, the minute lap collision load is efficiently transmitted from the partition wall 13b of the extension 13 to the second reinforcing plate 22, promoting deformation of the ridges of the second reinforcing plate 22 and the first reinforcing plates 21a, 21b, and 21c.

(4) The frame 11 is configured such that the first reinforcing plates 21a, 21b, and 21c are arranged along at least one edge line 11j1 or edge line 11j2 of the frame 11, and a bulkhead 25 is connected to the first reinforcing plates 21a, 21b, and 21c midway between the first reinforcing plates 21a, 21b, and 21c, spanning both the first reinforcing plates 21 and the frame 11, and weak portions (break points 11h and 11i) are formed near the connected bulkhead 25.

With this configuration, by forming a weak portion near the bulkhead 25 that reinforces the frame 11, the force of a collision is concentrated at the weak portion near the portion reinforced by the bulkhead 25. This ensures that the frame 11 can be broken in a collision, and the first reinforcing plates 21a, 21b, and 21c can also be broken at the ridges together with the frame 11, increasing the amount of collision energy absorbed.

(5) The bulkhead 25 is composed of at least a first bulkhead 25a as an engine mount fastening part and a second bulkhead 25b as a subframe fastening part, the first bulkhead 25a having a nut 26 with a screw hole on the upper surface, and the second bulkhead 25b having a nut 27 with a screw hole on the lower surface.

With this configuration, the engine mount bolts are screwed and fastened to the nuts 26 of the first bulkhead 25a, and the subframe bolts are screwed and fastened to the nuts 27 of the second bulkhead 25b, and the frame 11 can be broken at the breaking points 11g, 11h, and 11i, which serve as weak parts. Therefore, the entire length of the frame 11 can contribute to absorbing collision energy.

(6) The frame 11 has two upper and lower ridges 11j1 and 11j2 extending in the front-rear direction, and the first reinforcing plates 21a, 21b, and 21c have an upper first reinforcing plate 21b with an L-shaped cross section arranged along the upper ridge 11j2, and a lower first reinforcing plate 21a with an L-shaped cross section arranged along the lower ridge 11j1. A bulkhead 25 that divides the hollow portion of the frame 11 into front and rear portions is provided at the midpoint in the front-rear direction between the first reinforcing plates 21a, 21b, and 21c, and the frame 11 has a configuration having weak portions (break points 11h and 11i) near the bulkhead 25.

With this configuration, the first reinforcing plates 21a, 21b, and 21c break at the two ridges 11j1 and 11j2 of the frame 11 during a microlap collision, further increasing the amount of impact energy absorbed.

(7) The front end of the lower first reinforcing plate 21a is configured to be positioned forward of the front end of the upper first reinforcing plate 21b.

With this configuration, the front end of the lower first reinforcing plate 21a of the frame 11 protrudes forward a predetermined distance beyond the front end of the upper first reinforcing plate 21b, which suppresses deformation of the frame 11 in the event of a collision, such that the frame 11 is lifted as indicated by reference numeral 11A (see reference numeral 11A in FIG. 12), and promotes zigzag deformation in the vehicle width direction at the three bending points 11g, 11h, and 11i of the frame 11.

(8) The weak parts are multiple bend points 11g, 11h, and 11i formed on the frame 11 at intervals in the fore-and-aft direction, and the rear end of the upper first reinforcing plate 21b and the rear end of the lower first reinforcing plate 21a are positioned in the same position in the fore-and-aft direction of the vehicle body, and are also positioned in the same position as the rearmost bend point among the multiple bend points.

With this configuration, the rearmost bending point 11i among the bending points 11g, 11h, and 11i is more likely to break due to the difference in rigidity between the points with and without the first reinforcing plates 21a, 21b, and 21c, which promotes bending at the three bending points 11g, 11h, and 11i.

(9) The frame 11 has flanges 11a, 11b extending upward and downward from the upper and lower edges of the U-shaped cross section. The first bulkhead 25a, which represents one of the bulkheads 25 (first bulkhead 25a and second bulkhead 25b), has an upper extension portion 25a3 that extends a predetermined width so as to overlap the upper flange 11a, and a lower extension portion 25a4 that extends a predetermined width so as to overlap the lower flange 11b. The bulkhead 25 holds a nut 26 inside the center in the vehicle width direction, and the peripheral portion 25a2 of the first bulkhead 25a is overlapped and joined to the first reinforcing plates 21a, 21b arranged above and below in the U-shaped cross section of the frame 11, and the upper extension portion 25a3 and the lower extension portion 25a4 are sandwiched and joined between the upper and lower flanges 11a, 11b of the frame 11 and the back plate 15 that is joined to the flanges 11a, 11b and closes the opening of the U-shaped cross section.

This configuration makes it easy to assemble the bulkhead 25 to the frame 11, which is reinforced by the first reinforcing plates 21a and 21b, and allows an engine mount or subframe to be bolted to the bulkhead 25 at any position on the frame 11.

The vehicle body structure according to this embodiment has been described above, but the present invention is not limited to this, and can be modified as appropriate without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 10 Vehicle body front structure 11 Front side frame 11A Front side frame bent upward 11Z Zigzag-shaped front side frame 11a, 11b Flange 11c U-shaped cross-sectional portion 11e Enlarged U-shaped cross-sectional portion 11e1 Upper wall 11e2 Inner wall 11e3 Inclined wall 11e4 Outer wall 11g, 11h, 11i, 11n Bending point 11j1, 11j2 Ridge line 11k Closed cross section 12 Upper member 12a Front end portion 13 Bumper beam extension 13a Plate 13b Box-shaped portion 15 Back plate 18 Rear end member 21a, 21b, 21c First reinforcing plate 22 Second reinforcing plate 22a Lower end portion of second reinforcing plate 22b Rear end portion of second reinforcing plate 25 Bulkhead 25a First bulkhead 25b Second bulkhead 25a1, 25b1 Bulging portion 25a2 Peripheral edge portion 25a3 Upper extension portion 25a4 Lower extension portion

Claims (9)

A hollow front side frame extending in the front-rear direction;
A first reinforcing plate having an L-shaped cross section and disposed inside the front side frame;
a second reinforcing plate disposed inside the front side frame and forward of the first reinforcing plate,
The front side frame has a ridge line extending in the front-rear direction,
the first reinforcing plate is disposed so that a ridgeline of the L-shaped cross section is overlapped with a ridgeline of the front side frame,
The second reinforcing plate is offset outward in the vehicle width direction from the front end side relative to the rear end side , and is joined in a state in which the front end of the first reinforcing plate joined to the lower side of the U-shaped cross section of the front side frame and the rear end of the second reinforcing plate are in contact with each other and aligned.
A vehicle front structure. The front side frame includes a frame body having a U-shaped cross section that opens outward in the vehicle width direction, and a back plate that closes the opening and forms a hollow portion that extends in the vehicle front-rear direction,
The vehicle body front structure according to claim 1, characterized in that the second reinforcing plate has a rear end that abuts an inner wall of the frame main body and is inclined outward in the vehicle width direction from the rear end to the front end, forming a closed cross section between the back plate and the back plate, and the closed cross section is continuous with the hollow portion. A cylindrical bumper beam extension is provided at the front end of the front side frame,
The vehicle body front structure according to claim 2 , wherein a front end of the second reinforcing plate is arranged at a position overlapping in the vehicle width direction with a partition wall that divides the hollow portion of the bumper beam extension in the vehicle width direction. 2. The vehicle body structure according to claim 1, characterized in that the first reinforcing plate is arranged along at least one ridge line of the front side frame, a bulkhead is connected to the middle of the first reinforcing plate and spans both the first reinforcing plate and the front side frame, and a weak portion is formed in the vicinity of the bulkhead. 5. The vehicle body front structure according to claim 4, characterized in that the bulkhead comprises at least a first bulkhead as an engine mount fastening portion and a second bulkhead as a subframe fastening portion, the first bulkhead having a nut with a screw hole opening on an upper surface, and the second bulkhead having a nut with a screw hole opening on a lower surface. The front side frame has two upper and lower ridges extending in the front-rear direction,
The first reinforcing plate has an upper first reinforcing plate having an L-shaped cross section and arranged along the upper ridge line, and a lower first reinforcing plate having an L-shaped cross section and arranged along the lower ridge line,
a bulkhead that divides a hollow portion of the front side frame into front and rear portions is provided at a middle position of the first reinforcing plate in a front-rear direction,
The vehicle front body structure according to claim 1 , wherein the front side frame has a weak portion in the vicinity of the bulkhead. The vehicle front structure according to claim 6, characterized in that the front end of the lower first reinforcing plate is disposed forward of the front end of the upper first reinforcing plate. The weak portion is a plurality of bending points formed on the front side frame at intervals in the front-rear direction,
7. The vehicle body front structure according to claim 6, wherein a rear end of the upper first reinforcing plate and a rear end of the lower first reinforcing plate are disposed at the same position in the vehicle body fore-and-aft direction, and are disposed at the same position as a rearmost bending point among a plurality of bending points. The front side frame includes flanges extending upward and downward from upper and lower edges of the U-shaped cross section,
a bulkhead having an upper extension portion extending a predetermined width in a state where the upper extension portion overlaps the upper flange, and a lower extension portion extending a predetermined width in a state where the lower flange overlaps the lower flange;
3. The vehicle body front structure according to claim 2, characterized in that the bulkhead holds a nut inside at the center in the vehicle width direction, the peripheral portion of the bulkhead is overlapped and joined to the first reinforcing plate arranged above and below within the U-shaped cross section of the front side frame, and the upper extension portion and the lower extension portion are sandwiched and joined between upper and lower flanges of the front side frame and the back plate joined to the flanges and closing the opening of the U-shaped cross section.

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