JP7168440B2 - vehicle front structure - Google Patents

Description

The present invention relates to a vehicle front structure.

In Patent Document 1, in order to suppress bending of a bumper reinforcement (hereinafter referred to as a bumper RF) at the time of a so-called center pole collision and a small lap collision, a vehicle width direction central portion and a vicinity of both vehicle width direction ends of the bumper RF are disclosed. discloses a structure in which a center bulk and a side bulk are arranged respectively. Here, a center pole collision is a frontal collision with a columnar object near the center of the vehicle in the vehicle width direction, and a small lap collision is a collision in which the vehicle width direction edge slightly overlaps the colliding object. This is the case of a frontal collision in a state.

JP 2015-147437 A

By the way, in the above technique, it is conceivable that the bumper RF is bent at a position between the center bulk and the right side bulk or between the center bulk and the left side bulk at the time of collision with the center pole. Here, the above technique does not control the order of which of the left and right positions should be folded first.

However, the structure of the power unit behind the bumper RF and the dash part further behind is not symmetrical, and depending on the structure, it may be possible to reduce the amount of deformation of the passenger compartment by controlling the bending position and bending order of the bumper RF. There is Therefore, the above technique has room for improvement in this respect.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a vehicle front structure that reduces the amount of deformation of a passenger compartment by controlling the folding position and folding order of a bumper RF in the event of a collision with a center pole.

The vehicle front structure according to claim 1 includes a pair of left and right front side members arranged on both sides of the vehicle front portion and extending along the longitudinal direction of the vehicle, and arranged between the pair of left and right front side members. a power unit configured by connecting a right side device forming a right side portion and a left side device forming a left side portion to each other; a dash portion positioned behind the power unit and in front of the passenger compartment; a rear support portion provided in an area between the portion and the power unit for supporting the right device or the left device of the power unit when the power unit moves rearward of the vehicle; and a rear support portion extending along the vehicle width direction. a center portion connecting the front ends of the pair of left and right front side members to each other and having a larger cross-sectional area when viewed in the vehicle width direction than other portions adjacent in the vehicle width direction; a first bending starting portion provided on the same side as the right side device or the left side device supported by the rear support portion with respect to the center in the vehicle width direction and having a smaller cross-sectional area than the center portion; On the other hand, a bumper reinforcement having a second bending starting point portion provided on the opposite side of the right side device or the left side device supported by the rear support portion and having a larger cross-sectional area than the first bending starting point portion; Prepare.

In the vehicle front portion structure according to claim 1, the pair of left and right front side members are arranged on both sides of the vehicle front portion and extend along the vehicle front-rear direction. A power unit including a right device and a left device connected to each other is arranged between the pair of left and right front side members. A rear support portion is provided in an area between the dash portion behind the power unit and the power unit, and if the power unit moves to the rear of the vehicle, the right side device or left side device of the power unit is supported by the rear support portion. be. A bumper RF extends along the vehicle width direction and connects the front ends of the pair of left and right front side members.

A center portion in the vehicle width direction of the bumper RF has a larger cross-sectional area as viewed in the vehicle width direction than other portions adjacent in the vehicle width direction. Further, a first bending starting portion having a smaller cross-sectional area than the central portion is provided on the same side as the right side device or the left side device supported by the rear support portion with respect to the center in the vehicle width direction. A second fold having a cross-sectional area larger than that of the first fold starting point is provided on the side opposite to the right side device or the left side device supported by the rear support portion with respect to the center in the vehicle width direction, that is, on the side opposite to the first folding starting point portion. A starting point is provided.

Here, if the second folding starting point located on the opposite side of the right device or the left device supported by the rear supporting portion is broken before the first folding starting point, the second folding of the right device or the left device Since the device to which the starting point transmits the impact load is different from the device supported by the rear support, the shear input at the joint between the left and right devices is increased. Then, the connection between the left side device and the right side device is released (in other words, the power unit cracks), and only the device that receives the collision load from the second bending starting point moves toward the passenger compartment, causing the dash to move. There is a risk that the load will be locally transmitted through the dash and the amount of deformation of the dash portion will increase.

Therefore, in this vehicle front structure, the cross-sectional area of the bumper RF when viewed in the vehicle width direction is set so as to increase in the order of the first bending starting point, the second bending starting point, and the central portion. Therefore, the yield strength of each portion of the bumper RF increases in the order of the first bending starting point, the second bending starting point, and the central portion. As a result, when the center pole collides, the first bending starting point is firstly broken, and then the second bending starting point is set to break. In addition, since the position of the first bending starting point is set on the same side as the right side device or the left side device supported by the rear support portion with respect to the center in the vehicle width direction, the first bending starting point is set at the center pole collision. , the right side device and the left side device, the side device supported by the rear support portion is set to transmit the collision load.

In other words, since the device supported by the rear support part and the device that transmits the collision load to the first bending starting point that is the first to break are the same device, the shearing input generated at the connection part between the right side device and the left side device does not increase. As a result, power unit cracking is suppressed.

Furthermore, by suppressing power unit cracking, the reaction force from the power unit to the bumper RF increases at the first bending starting point. Therefore, the bumper RF is likely to be bent at the second bending starting point. When the second bending starting point is bent, the power unit is pushed rearward in the range between the first bending starting point and the second bending starting point of the bumper RF, and the collision load can be dispersed in the vehicle width direction. As a result, it is possible to suppress local input to the dash portion, thereby suppressing deformation of the passenger compartment.

As described above, according to the present invention, it is possible to reduce the amount of deformation of the passenger compartment by controlling the folding position and folding order of the bumper RF at the time of collision with the center pole.

1 is a schematic plan view showing a vehicle front structure of a first embodiment; FIG. FIG. 2 is a schematic plan view showing the moment when a center pole collision occurs in the vehicle front structure shown in FIG. 1 and the bumper RF is bent at the first bending starting point. FIG. 3 is a schematic plan view showing a moment when a bumper RF is broken at a second bending starting point in the vehicle front structure shown in FIGS. 1 and 2 ; FIG. 4 is a schematic plan view showing how a bumper RF presses a power unit in the vehicle front structure shown in FIGS. 1 to 3; It is a typical rear view which shows bumper RF from the vehicle rear. 6A is a sectional view taken along line 6A-6A of FIG. 5; FIG. (B) is a cross-sectional view taken along the line 6B-6B of FIG. 5; (C) is a cross-sectional view taken along line 6C-6C of FIG. (A) is a schematic plan view showing a bumper RF of the vehicle front structure according to the second embodiment. (B) is a schematic diagram showing bending strength characteristics of the bumper RF shown in (A). 7(A) is a schematic front view showing the bumper RF shown in FIG. 7(A) from the front of the vehicle; FIG. 9A is a sectional view taken along line 9A-9A of FIG. 8; FIG. 9B is a cross-sectional view taken along line 9B-9B of FIG. 8. FIG. (C) is a cross-sectional view taken along line 9C-9C of FIG. 8; (A) is a schematic plan view showing a bumper RF of a vehicle front structure according to a third embodiment. (B) is a schematic diagram showing bending strength characteristics of the bumper RF shown in (A). 11A is a sectional view taken along line 11A-11A of FIG. 10; FIG. 11B is a sectional view taken along line 11B-11B of FIG. 10; FIG. 11C is a sectional view taken along line 11C-11C of FIG. 10; FIG. FIG. 4 is a schematic plan view showing a vehicle front structure according to a comparative example;

[First embodiment]
A first embodiment of the present invention will be described below with reference to FIGS. 1 to 6 and 12. FIG.

An arrow FR, an arrow UP, an arrow RH, and an arrow LH shown in each figure indicate the front direction, the upward direction, the right side of the vehicle, and the left side of the vehicle, respectively. Further, in the following description, when front-rear, left-right, and up-down directions are used unless otherwise specified, front-rear in the vehicle front-rear direction, left and right in the vehicle width direction, and up and down in the vehicle vertical direction.

As shown in FIG. 1, the vehicle front structure S1 of this embodiment includes a pair of left and right front side members 10 arranged on both sides of the vehicle front portion. The front side member 10 is a vehicle body frame member whose longitudinal direction is oriented in the vehicle front-rear direction, and is provided symmetrically with respect to the center line in the vehicle width direction of the vehicle.

A front end portion of the front side member 10 is a deformed portion 12 . The deformable portion 12 has lower compressive strength against a load in the longitudinal direction of the vehicle than the body portion 14 (the portion of the front side member 10 other than the deformable portion 12). Examples of the deformable portion 12 include crash boxes made of aluminum or fiber-reinforced plastic.

The vehicle front structure S1 also includes a bumper RF20. The bumper RF 20 is a vehicle body frame member extending along the vehicle width direction, and connects the front ends of the pair of left and right front side members 10 to each other. Specifically, the front ends of the deformation portions 12 of the pair of left and right front side members 10 are coupled to the rear surface of the bumper RF20. Although the bumper RF 20 extending linearly in the vehicle width direction is schematically illustrated, the bumper RF 20 has a shape in which both sides in the vehicle width direction are obliquely bent toward the vehicle rear side, that is, the bumper RF 20 as a whole It may have an arcuate shape convex to the side. A more detailed configuration of the bumper RF 20 will be described later.

The vehicle front structure S1 also includes a power unit 30 arranged between the pair of left and right front side members 10 and behind the bumper RF 20 in the vehicle. The power unit 30 is configured by connecting a transaxle 30L as a "left side device" and an engine 30R as a "right side device" to each other. The power unit 30 is supported by the body portions 14 of the pair of left and right front side members 10 via left and right engine mounts 32 . Although not shown, the power unit 30 is also supported from below the vehicle at the transaxle 30L. Further, the width dimension of the engine 30R is larger than the width dimension of the transaxle 30L, and the connecting portion 34 is shifted to the left with respect to the center in the vehicle width direction.

The vehicle front structure S1 also includes a dash portion 40 . Dash portion 40 is a portion that separates a space (engine compartment) in which power unit 30 is arranged from a vehicle interior (not shown). That is, the dash portion 40 constitutes the front end of the passenger compartment. The dash portion 40 includes a dash panel 42 and a dash cloth (not shown). Rear ends of a pair of left and right front side members 10 are coupled to the dash panel 42 . A kick-up portion (not shown) may be provided on the vehicle rear side of the front side member 10, and the dash panel 42 may be arranged above the kick-up portion.

A gearbox 44 is provided in front of the dash panel 42 , and the gearbox 44 is arranged so as to protrude toward the front side of the vehicle with respect to the dash panel 42 . Therefore, in the present embodiment, if the power unit 30 moves rearward of the vehicle (for example, moves parallel), the gearbox 44 supports the power unit 30 . That is, in this embodiment, the gearbox 44 corresponds to the "rear support" of the invention. The gearbox 44 is arranged at a position shifted to the left with respect to the center in the vehicle width direction and behind the transaxle 30L.

Next, a detailed configuration of the bumper RF 20 will be described with reference to FIGS. 5 and 6. FIG.

FIG. 5 shows a rear view of the bumper RF 20 viewed from behind the vehicle. As shown in this figure, the bumper RF 20 includes a left side portion 20A provided on the left side in the vehicle width direction, a central portion 20B provided in the central portion in the vehicle width direction adjacent to the left side portion 20A, and a central portion 20B. and a right side portion 20C provided adjacently on the right side in the vehicle width direction.

The bumper RF 20 is configured such that the central portion 20B has the largest vertical dimension (height dimension), the right side portion 20C has the second largest height dimension, and the left side portion 20A has the smallest height dimension. . The bumper RF 20 also has a first bend starting portion 20D at the boundary between the left side 20A and the central portion 20B, and a second bending starting portion 20E at the boundary between the central portion 20B and the right side 20C. 1 to 5, the hatched patterns respectively applied to the left side 20A, the central portion 20B, and the right side 20C are intended to show the correspondence between the figures in an easy-to-understand manner. Actually, the left side portion 20A, the central portion 20B, and the right side portion 20C of the bumper RF are integrally formed by extruding a metal such as aluminum.

6A to 6C show sectional views of the left side portion 20A, the central portion 20B, and the right side portion 20C of the bumper RF 20 as seen from the right side in the vehicle width direction.

By the way, the bumper RF 20 is integrally formed by extrusion as described above, and the central portion 20B has the same shape as the extruded material obtained by extrusion. In other words, the extruded material has the cross-sectional shape shown in FIG. 6(B). On the other hand, the left side 20A and the right side 20C, as shown in FIGS. 6A and 6C, are formed by cutting an extruded material obtained by extrusion molding to change the cross-sectional shape. can get. Each portion of bumper RF 20 is described in more detail below.

As shown in FIG. 6B, the central portion 20B of the bumper RF 20 has a hollow structure with an eye-shaped cross section. Specifically, the front wall 20F and the rear wall 20G, which are spaced apart from each other on the front side and the rear side of the vehicle, and the upper end portions and the lower end portions of the front wall 20F and the rear wall 20G are connected to each other in the vehicle front-rear direction. It includes an upper wall 20H, a lower wall 20I, and a first lateral wall 20J and a second lateral wall 20K that connect the front wall 20F and the rear wall 20G in the longitudinal direction of the vehicle. The first lateral wall 20J and the second lateral wall 20K divide the closed cross section in the central portion 20B into three in the vertical direction.

As shown in FIG. 6(C), the right side portion 20C is formed by cutting off the portion above the first horizontal wall 20J of the extruded material by cutting or the like. That is, the upper surface of the right side portion 20C is formed by the first lateral wall 20J, and the front and rear sides of the vehicle are the front wall 20F1 and the rear wall 20F1, which are portions of the front wall 20F and the rear wall 20G that are lower than the upper surface of the first lateral wall 20J. It is configured by the wall 20G1. Therefore, the cross-sectional area of the right side portion 20C viewed from the right side in the vehicle width direction is smaller than the cross-sectional area of the central portion 20B. As a result, the bending resistance of the right side portion 20C is smaller than that of the central portion 20B.

As shown in FIG. 6A, the left side portion 20A is formed by cutting off a portion of the extruded material above the second lateral wall 20K by cutting or the like. That is, the upper surface of the left side portion 20A is constituted by the second lateral wall 20K, and the front side and the rear side of the vehicle are the front wall 20F2 and the rear wall 20F2, which are portions of the front wall 20F and the rear wall 20G below the upper surface of the second lateral wall 20K. It is configured by the wall 20G2. Therefore, the cross-sectional area of the left side portion 20A viewed from the right side in the vehicle width direction is smaller than the cross-sectional area of the right side portion 20C. As a result, the bending strength of the left side portion 20A is even smaller than that of the right side portion 20C.

As described above, the bumper RF is configured such that the left side portion 20A has the smallest cross-sectional area when viewed from the right side in the vehicle width direction, the right side portion 20C has the second smallest cross-sectional area, and the central portion 20B has the largest cross-sectional area. ing.

In addition, the bumper RF 20 has the number of walls extending in the direction in which the load from the pole P is input at the time of collision with the center pole (the direction toward the rear of the vehicle), that is, the front walls 20F, 20F1, 20F2 and the rear walls 20G, 20G1. , 20G2 is also different depending on each part. Specifically, the left side portion 20A has two pieces, a second lateral wall 20K and a lower wall 20I. Also, the right side portion 20C has three pieces including the first lateral wall 20J. Further, the central portion 20B has four pieces including the upper wall 20H.

As described above, the left side portion 20A, the central portion 20B, and the right side portion 20C have different bending resistance due to the different cross-sectional areas and cross-sectional shapes. That is, the left side portion 20A, which has the smallest cross-sectional area and the smallest number of wall portions bridging between the front wall 20F2 and the rear wall 20G2, has the smallest bending strength. The bending strength of the right side portion 20C, which has the next smallest cross-sectional area and the next smallest number of wall portions bridging between the front wall 20F1 and the rear wall 20G1, is small. The central portion 20B, which has the largest cross-sectional area and the largest number of wall portions bridging between the front wall 20F and the rear wall 20G, is configured to have the largest bending resistance. As a result, the boundary portion between the left side portion 20A and the central portion 20B of the bumper RF 20 is the most likely to be bent, and constitutes a first bending starting point portion 20D that is first to be bent when colliding with the center pole. A boundary portion between the central portion 20B and the right side portion 20C constitutes a second folding starting portion 20E that folds after the first folding starting portion 20D.

In other words, the bumper RF 20 has two bending starting points (a first bending starting point 20D and a second bending starting point 20E) across the central portion 20B. The bending strength of the first bending starting point 20D is set lower than that of the second bending starting point 20E. By providing a proof stress difference in each part of the bumper RF 20 in this way, the first bending starting point 20D of the bumper RF 20 is the first to break when colliding with the center pole, and the second bending starting point 20E is next to the first bending starting point 20D. The order of folding is controlled so that it can be folded.

In other words, the bumper RF20 has the same cross-sectional width (vehicle front-rear dimension) along the vehicle width direction, but the cross-sectional height (vehicle vertical dimension) is , the central portion 20B, the second bending starting portion 20E, and the first bending starting portion 20D. Therefore, the moment of inertia of area also decreases in this order. Since the entire bumper RF20 is made of the same material by extrusion molding, each part has the same Young's modulus. Therefore, the bending rigidity (difficulty in bending) also decreases in the order of the central portion 20B, the second bending starting portion 20E, and the first bending starting portion 20D. That is, the first bending starting portion 20D is most susceptible to bending deformation, followed by the second bending starting portion 20E.

<Effect>
Next, the effect of 1st Embodiment is demonstrated, comparing with the comparative example shown in FIG.

As shown in FIG. 12, in the vehicle front structure S2 according to the comparative example, the bumper RF100 is integrally formed by extrusion molding and does not have a portion whose cross-sectional shape is changed with respect to the extruded material. In other words, the bumper RF100 has an eye-shaped cross section as a whole shown in FIG. 6(B). Therefore, the position at which the bumper RF 100 folds and the sequence of folding are not controlled. Therefore, as shown in FIG. 12, when the engine 30R collides with the pole P and breaks at the bending starting point 100A on the side of the engine 30R, the engine 30R is not supported by the gearbox 44. As a result, the shear input generated at the connecting portion 34 between the engine 30R and the transaxle 30L increases. Then, the connection between the engine 30R and the transaxle 30L is released (in other words, the power unit is cracked), and only the engine 30R, which receives the collision load from the bending starting point 100A, moves toward the passenger compartment. There is a possibility that the load is locally transmitted to the dash portion 40 and the amount of deformation of the dash portion 40 increases.

On the other hand, in the present embodiment, as shown in FIGS. 1 to 4, a pair of left and right front side members 10 extend along the front-rear direction of the vehicle. A bumper RF 20 extends along the vehicle width direction and connects the front ends of the pair of left and right front side members 10 . A power unit 30 is arranged between the pair of left and right front side members 10 and behind the bumper RF 20 in the vehicle.

The power unit 30 is configured by connecting an engine 30R forming a right portion and a transaxle 30L forming a left portion to each other. Since the gearbox 44 is provided in the area between the dash portion 40 and the power unit 30, if the power unit 30 moves rearward of the vehicle (for example, parallel movement), the transaxle 30L of the power unit 30 is shifted to the gear. Box 44 is supported first.

A center portion 20</b>B having a larger cross-sectional area when viewed in the vehicle width direction than other portions adjacent in the vehicle width direction is provided in the vehicle width direction center portion of the bumper RF 20 . Further, a first bending starting portion 20D having a smaller cross-sectional area than the central portion 20B is provided on the same side as the transaxle 30L supported by the gearbox 44 with respect to the vehicle width direction center. Then, on the side opposite to the transaxle 30L supported by the gearbox 44 with respect to the vehicle width direction center, that is, on the side opposite to the first bending starting point 20D, a second bending having a larger cross-sectional area than the first bending starting point 20D is provided. A starting point 20E is provided.

As a result, in the vehicle front structure S1 of the present embodiment, as shown in FIGS. 30L is set to transmit the impact load to the device on the side supported by the gearbox 44,
Therefore, in the vehicle front structure S1 of the present embodiment, it is easy to realize the deformation mode described below at the time of collision with the center pole.

That is, when the bumper RF 20 collides with the center pole, as shown in FIG. It folds at the first fold starting portion 20D which is the boundary portion with the small left side portion 20A. Next, as shown in FIG. 3 , the first bending starting portion 20D of the bumper RF 20 transmits the collision load (indicated by arrow F) to the transaxle 30L of the power unit 30. As shown in FIG. When the power unit 30 moves rearward of the vehicle due to the collision load, the power unit 30 (transaxle 30L) is supported by the gearbox 44 . Here, since the device (transaxle 30L) supported by the gearbox 44 and the device (transaxle 30L) to which the first bending starting point portion 20D transmits the collision load are the same device, the engine 30R and the transaxle 30L There is no increase in the shear input generated at the connecting portion 34 with the . As a result, power unit cracking is suppressed.

Furthermore, by suppressing power unit cracking, the reaction force (the reaction force against the force indicated by arrow F in FIG. 3) from the power unit 30 to the bumper RF 20 at the first bending starting point 20D increases. For this reason, as shown in FIG. 3, the bumper RF 20 has a second fold, that is, a second fold starting point that is a boundary portion between the central portion 20B having the largest cross-sectional area and the right side portion 20C having the second largest cross-sectional area. Folding of 20E is likely to occur. When the second bending starting point 20E is bent, as shown in FIG. 4, the power unit 30 is pushed rearward in the range between the first bending starting point 20D and the second bending starting point 20E in the bumper RF 20 ( (This means surface pressing), and the collision load can be distributed in the vehicle width direction. As a result, it is possible to suppress local input to the dash portion 40, thereby suppressing deformation of the passenger compartment.

Further, although simplified in the drawings, the rear surface of the power unit 30 has an uneven shape. In the present embodiment, of the rear surface having the uneven shape, the rearmost portion in the vehicle front-rear direction faces the gear box 44 in the vehicle front-rear direction. That is, the vehicle front-rear direction rear end portion of the power unit 30 is supported by the dash portion 40 first. Therefore, the power unit 30 can be supported from behind in an early stage after the occurrence of the center pole collision.

Although the description is omitted for the sake of simplification, between the bumper RF 20 and the power unit 30, a cooling unit or the like (not shown) is usually arranged. Therefore, when a center pole collision occurs and the first bend starting portion 20D of the bumper RF20 is bent and displaced toward the power unit 30, the collision load is transmitted from the bumper RF20 to the power unit 30 via the cooling unit and the like.

In this embodiment, the bumper RF 20 is integrally formed by extrusion over the entire length in the vehicle width direction, and the left side portion 20A is changed by cutting the extruded material obtained by the extrusion, for example, and changing the cross-sectional shape. and the right side portion 20C, but the present invention is not limited to this. For example, the left side portion 20A, the central portion 20B and the right side portion 20C are separately formed by extrusion molding so as to have cross-sectional shapes shown in FIGS. may

[Second embodiment]
A second embodiment of the present invention will be described below with reference to FIGS. 7(A) to 9(C). In addition, in these figures, the same reference numerals are assigned to the same components as those of the first embodiment described above, and the description thereof is omitted.

FIG. 7A schematically shows a plan view of the bumper RF50 of the vehicle front structure according to the second embodiment. As shown in this figure, the bumper RF 50 includes a rear member 52 whose rear surface is joined to the front ends of the deformation portions 12 of the pair of left and right front side members 10, and is arranged adjacent to the rear member 52 on the front side of the vehicle. and a front member 56 arranged adjacent to the vehicle front side of the intermediate member 54 . The rear member 52, the intermediate member 54, and the front member 56 are separately formed by extrusion molding of metal such as aluminum, and are joined by welding, bolting, or the like, for example.

The intermediate member 54 has its rear surface joined to the front surface of the rear member 52 and extends from the vehicle width direction right end of the rear member 52 to a position on the left side of the vehicle width direction center. In other words, the intermediate member 54 entirely overlaps a portion of the vehicle width direction right side of the rear member 52 as viewed from the vehicle rear side.

The front member 56 has its rear surface joined to the front surface of the intermediate member 54 and extends from the vehicle width direction left end of the intermediate member 54 to a position on the right side of the vehicle width direction center of the bumper RF 50 . In other words, the front member 56 entirely overlaps a part of the left side of the intermediate member 54 in the vehicle width direction when viewed from the rear side of the vehicle. Further, the front member 56 is arranged substantially at the center of the bumper RF 50 in the vehicle width direction.

As shown in FIG. 7A, the portion of the bumper RF 50 that is configured by the rear member 52, the intermediate member 54, and the front member 56 constitutes a central portion 60 of the bumper RF 50 in the vehicle width direction. ing. A left side portion 62 is a portion of the bumper RF 50 that is arranged to the left of the center portion 60 in the vehicle width direction and that is configured only by the rear side member 52 . Furthermore, a right side portion 64 is a portion that is arranged on the right side of the central portion 60 in the vehicle width direction and that is configured by the rear side member 52 and the intermediate member 54 . That is, the vehicle front-rear direction dimensions of the respective parts constituting the bumper RF 50 are set so as to decrease in the order of the central part 60 , the right side part 64 , and the left side part 62 .

In other words, the bumper RF 50 has a rear member 52, an intermediate member 54, and a front member 56 that overlap when viewed from the front of the vehicle, and the closer the member is to the front of the vehicle, the smaller the dimension in the vehicle width direction. is configured as Here, the entire rear surface of the intermediate member 54 faces one end side of the front surface of the rear member 52 in the vehicle width direction. In addition, the entire rear surface of the front member 56 faces the other end of the front surface of the intermediate member 54 in the vehicle width direction. By arranging the three members in this manner, three portions having different dimensions in the longitudinal direction of the vehicle, that is, a central portion 60, a left portion 62 and a right portion 64 are formed.

As shown in FIG. 8, the dimension of the bumper RF 50 in the vehicle vertical direction is constant or substantially constant along the vehicle width direction. That is, the dimensions in the vertical direction of the vehicle of the central portion 60, the left side portion 62 and the right side portion 64 are substantially the same. Therefore, the cross-sectional area of each part of the bumper RF 50 viewed from the vehicle width direction is set so as to decrease in the order of the central part 60, the right side part 64, and the left side part 62, similarly to the dimension in the longitudinal direction of the vehicle.

Next, with reference to FIGS. 9A to 9C, cross-sectional shapes of respective parts of the bumper RF 50 will be described.

The left side portion 62 is composed of only the rear side member 52, as shown in FIG. 9(C). The rear side member 52 (left side portion 62) has a hollow structure in which the cross section viewed from the vehicle width direction has an eye shape. Specifically, the rear member 52 includes a front wall 52A and a rear wall 52B that are spaced apart from each other on the front side and the rear side of the vehicle, and upper and lower ends of the front wall 52A and the rear wall 52B that are separated from each other by the vehicle. It includes an upper wall 52C and a lower wall 52D that connect in the longitudinal direction, and a first lateral wall 52E and a second lateral wall 52F that connect the front wall 52A and the rear wall 52B in the longitudinal direction of the vehicle. The first lateral wall 52E and the second lateral wall 52F vertically divide the closed cross section inside the rear member 52 into three sections.

The right side portion 64 is composed of a rear side member 52 and an intermediate member 54, as shown in FIG. 9(A). The intermediate member 54 has a hollow structure in which the cross section viewed from the vehicle width direction is in the shape of the Japanese character. Specifically, the intermediate member 54 connects a front wall 54A and a rear wall 54B spaced apart from each other on the front side and the rear side of the vehicle, and upper end portions and lower end portions of the front wall 54A and the rear wall 54B. It includes an upper wall 54C and a lower wall 54D that connect in the direction of the vehicle, and a lateral wall 54E that connects the front wall 54A and the rear wall 54B in the longitudinal direction of the vehicle. The closed cross section in the intermediate member 54 is vertically divided into two by the lateral wall 54E. The right side portion 64 is configured by joining the front surface of the front wall 52A of the rear member 52 to the rear surface of the rear wall 54B of the intermediate member 54 .

The central portion 60 is composed of a rear member 52, an intermediate member 54, and a front member 56, as shown in FIG. 9B. The front member 56 has a hollow structure with a rectangular frame-like cross section when viewed in the vehicle width direction. Specifically, the front side member 56 is arranged so that a front wall 56A and a rear wall 56B, which are spaced apart from each other on the front side and the rear side of the vehicle, and upper end portions and lower end portions of the front wall 56A and the rear wall 56B are connected to the front and rear of the vehicle. It includes an upper wall 56C and a lower wall 56D that are connected in the respective directions. In the central portion 60, the front surface of the front wall 52A of the rear member 52 is joined to the rear surface of the rear wall 54B of the intermediate member 54, and the front surface of the front wall 54A of the intermediate member 54 is joined to the rear surface of the rear wall 56B of the front member 56. It is constructed by joining.

As shown in FIGS. 9A to 9C, in this embodiment, the rear member 52, the intermediate member 54, and the front member 56 are each formed uniformly over the entire length in the vehicle width direction. ing. In addition, the dimension of the rear member 52 in the longitudinal direction of the vehicle is set larger than those of the intermediate member 54 and the front member 56 .

Next, bending strength characteristics of the bumper RF50 will be described. FIG. 7(B) schematically shows a diagram showing the bending strength characteristic with respect to the position of the bumper RF50 in the vehicle width direction. As described above, the cross-sectional area of each part of the bumper RF 50 viewed from the vehicle width direction is set so as to decrease in the order of the central part 60, the right side part 64, and the left side part 62. As shown in FIG. For this reason, the bending strength of each portion constituting the bumper RF 50 also decreases in the order of the central portion 60, the right side portion 64, and the left side portion 62. As shown in FIG. That is, there is a proof stress difference (indicated by arrow D) between the right side portion 64 and the left side portion 62 . Although not shown in the first embodiment, the bending strength characteristics of the bumper RF20 of the first embodiment are similar to the bending strength characteristics of the bumper RF50 of the second embodiment shown in FIG. 7B. have.

By having the bending resistance characteristics as described above, as shown in FIGS. 7A and 8, the boundary portion between the left side portion 62 having the lowest bending resistance and the central portion 60 having the highest bending resistance of the bumper RF 50 is , constitutes a first bending starting portion 66 that is first bent when colliding with the center pole. In addition, the boundary portion between the right side portion 64 having the second lowest bending strength and the central portion 60 having the highest bending resistance constitutes a second bending starting point portion 68 that is broken next to the first bending starting point portion 66 . That is, the bumper RF 50 has a first bending starting point portion 66 having a smaller cross-sectional area than the central portion 60 and a second bending starting point portion having a larger cross-sectional area than the first bending starting point portion 66 on both sides of the central portion 60 in the vehicle width direction. 68.

The first bending starting portion 66 is arranged on the left side in the vehicle width direction of the center in the vehicle width direction, and is arranged so as to overlap the transaxle 30L (see FIG. 1) when viewed from the front side of the vehicle. Further, the second bending starting portion 68 is arranged on the vehicle width direction right side of the vehicle width direction center, and is arranged so as to overlap with the engine 30R (see FIG. 1) when viewed from the vehicle front side.

In other words, the bumper RF50 has a cross-sectional shape and dimensions as viewed in the vehicle width direction such that the geometrical moment of inertia decreases in the order of the central portion 60, the second bending starting point portion 68, and the first bending starting point portion 66. is set to In addition, in this embodiment, the entire bumper RF50 is made of the same material by extrusion molding, so that each part has the same Young's modulus. Therefore, the flexural rigidity also decreases in the order of the central portion 60, the second bending starting portion 68, and the first bending starting portion 66. As shown in FIG. That is, the first bending starting portion 66 is most susceptible to bending deformation, followed by the second bending starting portion 68 .

<Effect>
Next, the effects of the second embodiment will be described.

In the second embodiment, the bumper RF 50 includes a central portion 60 having a larger cross-sectional area when viewed from the vehicle width direction than other portions adjacent to the vehicle width direction, and a first bending starting portion having a smaller cross-sectional area than the central portion 60. 66 and a second bending starting point 68 having a larger cross-sectional area than the first bending starting point 66 . Therefore, a proof stress difference D (see FIG. 7B) is provided between the first bend starting point 66 and the second bending starting point 68, and the bending proof stress of the first bending starting point 66 is smaller. ing. As a result, as in the first embodiment, the bending position and order are controlled so that the first bending starting portion 66 is first bent and then the second bending starting portion 68 is bent when colliding with the center pole. Here, since the device supported by the gearbox 44 (see FIG. 1) and the device to which the first bending starting point 66 transmits the collision load are the same device (transaxle 30L, see FIG. 1), the power unit cracks is suppressed. In addition, the power unit 30 is pushed rearward in the range between the first bending starting point 66 and the second bending starting point 68 of the bumper RF 50 (face pushing), and the collision load can be dispersed in the vehicle width direction. As a result, it is possible to suppress local input to the dash portion 40, thereby suppressing deformation of the passenger compartment.

In this embodiment, as shown in FIG. 9B, an example in which the rear member 52, the intermediate member 54, and the front member 56 have substantially the same dimensions in the vertical direction of the vehicle has been described. is not limited to For example, the dimensions in the vertical direction of the vehicle of the intermediate member 54 and the front member 56 may be set smaller than that of the rear member 52 .

In addition, in the present embodiment, the bumper RF 50 has a cross section viewed from the vehicle width direction in which the rear member 56 has an eye shape, the intermediate member 54 has a sun shape, and the front member 56 has a rectangular cross section. Although it is frame-shaped, the present invention is not limited to this. For example, the rear member 52, the intermediate member 54, and the front member 56 may be configured to have the same cross-sectional shape, for example, an eye shape, or the rear member 52 may be eye-shaped, the intermediate member 54, and the front member 56 may be configured to have the same cross-sectional shape. Each of the members 56 may be configured to have a cross-sectional shape of a Japanese letter or a rectangular frame.

Further, in the present embodiment, an example is shown in which the bumper RF 50 is configured by the rear member 52, the intermediate member 54, and the front member 56 which are separately formed by extrusion molding and joined in the longitudinal direction of the vehicle. The invention is not so limited. For example, the central portion 60, the left side 62, and the right side 64 having cross-sectional shapes shown in FIGS. 9A to 9C may be separately formed by extrusion molding and joined in the vehicle width direction. good. Even in this case, the cross-sectional area is configured to decrease in the order of the central portion 60 , the right portion 64 and the left portion 62 .

[Third Embodiment]
A third embodiment of the present invention will be described below with reference to FIGS. 10(A) to 11(C). In addition, in these figures, the same reference numerals are assigned to the same components as those of the first and second embodiments described above, and the description thereof will be omitted.

FIG. 10A schematically shows a plan view of a bumper RF70 of the vehicle front structure according to the third embodiment. As shown in this figure, the bumper RF 70 includes a rear member 72 whose rear surface is joined to the front ends of the deformation portions 12 of the pair of left and right front side members 10, and is arranged adjacent to the rear member 72 on the front side of the vehicle. and a front member 76 arranged adjacent to the vehicle front side of the intermediate member 74 . The rear member 72 is formed by extruding metal such as aluminum. The intermediate member 74 and the front member 76 are each made of a steel plate and joined to each other by welding or the like. Also, the rear member 72 and the intermediate member 74 are joined by an adhesive or the like.

The intermediate member 74 extends from the vehicle width direction right end of the rear member 72 to a position on the left side of the vehicle width direction center. In other words, the intermediate member 74 entirely overlaps a portion of the vehicle width direction right side of the rear member 72 as viewed from the vehicle rear side.

The front member 76 extends from the vehicle width direction left end portion of the intermediate member 74 to a position on the right side of the vehicle width direction center of the bumper RF 70 . In other words, the front member 76 entirely overlaps a left portion of the intermediate member 74 in the vehicle width direction when viewed from the vehicle rear side. Further, the front member 76 is arranged substantially at the center of the bumper RF 70 in the vehicle width direction.

As shown in FIG. 10A, the portion of the bumper RF 70 that is configured by the rear member 72, the intermediate member 74, and the front member 76 constitutes a central portion 80 of the bumper RF 70 in the vehicle width direction. ing. A left side portion 82 is a portion of the bumper RF 70 that is arranged to the left of the center portion 80 in the vehicle width direction and is composed of only the rear side member 72 . Furthermore, a right side portion 84 is a portion that is arranged on the right side of the central portion 80 in the vehicle width direction and that is configured by the rear side member 72 and the intermediate member 74 . That is, the vehicle front-rear direction dimensions of the parts constituting the bumper RF 70 are set so as to decrease in the order of the central part 80 , the right side part 84 , and the left side part 82 .

Although not shown, the dimension of the bumper RF 70 in the vehicle vertical direction is constant or substantially constant along the vehicle width direction. That is, the dimensions in the vehicle vertical direction of the central portion 80, the left side portion 82, and the right side portion 84 are substantially the same. In addition, the cross-sectional area of each part of the bumper RF 70 viewed from the vehicle width direction is set so as to decrease in the order of the central part 80 , the right side part 84 and the left side part 82 .

Next, referring to FIGS. 11(A) to 11(C), the cross-sectional shape of each part of the bumper RF 70 will be described.

The left side portion 82 is composed only of the rear side member 72, as shown in FIG. 11(C). The rear side member 72 (left side portion 82) includes a front wall 72A and a rear wall 72B which are spaced apart from each other on the front side and the rear side of the vehicle, and upper end portions and lower end portions of the front wall 72A and the rear wall 72B. It includes an upper wall 72C and a lower wall 72D that connect in the longitudinal direction, and a first lateral wall 72E and a second lateral wall 72F that connect the front wall 72A and the rear wall 72B in the longitudinal direction of the vehicle. The first lateral wall 72E and the second lateral wall 72F divide the closed cross section inside the rear member 72 into three in the vertical direction.

The right side portion 84 is composed of a rear side member 72 and an intermediate member 74, as shown in FIG. 11(A). The intermediate member 74 is made of a steel plate and has a rear surface joined to the front surface of the front wall 72A of the rear member 72 .

The central portion 80 is composed of a rear member 72, an intermediate member 74, and a front member 76, as shown in FIG. 11(B). The front member 76 is made of a steel plate and has a rear surface joined to the front surface of the intermediate member 74 . Further, the plate thickness of the intermediate member 74 is set thicker than that of the front member 76 . The plate thickness of the intermediate member 74 and the front member 76 may be the same, or the plate thickness of the intermediate member 74 may be thinner.

As shown in FIGS. 11A to 11C, in this embodiment, the rear member 72, the intermediate member 74, and the front member 76 are each formed uniformly over the entire length in the vehicle width direction. ing.

Next, bending strength characteristics of the bumper RF70 will be described. FIG. 10(B) schematically shows a diagram showing the bending strength characteristic with respect to the position of the bumper RF70 in the vehicle width direction. As described above, the cross-sectional area of each part of the bumper RF 70 viewed from the vehicle width direction is set so as to decrease in the order of the central part 80, the right side part 84, and the left side part 82. As shown in FIG. For this reason, the bending strength of each portion constituting the bumper RF 70 also decreases in the order of the central portion 80, the right side portion 84, and the left side portion 82. As shown in FIG. In other words, there is a tolerance difference (indicated by arrow E) between the right side portion 84 and the left side portion 82 .

Due to the above bending resistance characteristics, as shown in FIG. 10A, the boundary portion between the left side portion 82 having the lowest bending resistance and the central portion 80 having the highest bending resistance of the bumper RF 70 is initially It constitutes a first folding starting portion 86 that folds inward. A boundary portion between the right portion 84 having the second lowest bending strength and the central portion 80 having the highest bending resistance constitutes a second bending starting portion 88 that is broken next to the first bending starting portion 86 . That is, the bumper RF 70 includes a first bending starting point portion 86 having a smaller cross-sectional area than the central portion 80 and a second bending starting point portion having a larger cross-sectional area than the first bending starting point portion 86 on both sides of the central portion 80 in the vehicle width direction. 88.

The first bending starting point 86 is arranged on the left side in the vehicle width direction of the center in the vehicle width direction, and is arranged so as to overlap the transaxle 30L (see FIG. 1) when viewed from the front side of the vehicle. Further, the second bending starting portion 88 is arranged on the vehicle width direction right side of the vehicle width direction center, and is arranged so as to overlap with the engine 30R (see FIG. 1) when viewed from the vehicle front side.

In other words, the bumper RF 70 has a cross-sectional shape and dimensions as viewed in the vehicle width direction such that the geometrical moment of inertia decreases in the order of the central portion 80, the second bending starting point portion 88, and the first bending starting point portion 86. is set to In this embodiment, the rear member 72 is made of metal such as aluminum, and the intermediate member 74 and the front member 76 are each made of steel plate. Since the Young's modulus of steel plate is higher than that of aluminum, parts using steel plate have high bending rigidity. Therefore, the flexural rigidity also decreases in the order of the central portion 80, the second bending starting portion 88, and the first bending starting portion 86. As shown in FIG. That is, the first bending starting portion 86 is most susceptible to bending deformation, followed by the second bending starting portion 88 .

<Effect>
Next, the effects of the third embodiment will be described.

In the third embodiment, the bumper RF 70 includes a central portion 80 having a larger cross-sectional area when viewed in the vehicle width direction than other portions adjacent in the vehicle width direction, and a first bending starting portion having a smaller cross-sectional area than the central portion 80. 86 and a second bending starting portion 88 having a larger cross-sectional area than the first bending starting portion 86 . Therefore, a proof stress difference E (see FIG. 10B) is provided between the first bend starting point portion 86 and the second bending starting point portion 88, and the bending proof stress of the first bending starting point portion 86 is smaller. ing. That is, the positions and order of folding are controlled so that the first folding starting point 86 is first folded and then the second folding starting point 88 is broken when the center pole collides. As a result, similar to the first embodiment and the second embodiment, it is possible to suppress local input to the dash portion 40, thereby suppressing deformation of the passenger compartment.

In addition, since the intermediate member 74 and the front member 76 are each made of a steel plate and have higher strength than aluminum or the like, the cross-sectional area is smaller than when aluminum or the like is used for the intermediate member 74 and front member 76. plate thickness) to obtain the desired bending strength. Therefore, compared to the case where aluminum or the like is used for the intermediate member 74 and the front member 76, the folding order of the bumper RF70 can be controlled while reducing the dimension of the bumper RF70 in the vehicle longitudinal direction.

In this embodiment, as shown in FIG. 11(B), an example in which the rear member 72, the intermediate member 74, and the front member 76 have substantially the same dimensions in the vertical direction of the vehicle has been described. is not limited to For example, the dimensions of the intermediate member 74 and the front member 76 in the vertical direction of the vehicle may be set smaller than that of the rear member 72 .

[Supplementary explanation of the above embodiment]
In the above embodiment, the gearbox 44 protrudes forward of the vehicle with respect to the dash panel 42, which is a general portion of the dash portion 40, and functions as a "rear support portion". Not limited.

For example, a part of the power unit 30 protrudes rearward, and this part is first supported by, for example, the dash panel 42 in the dash part 40 (in this case, part of the dash panel 42 is the "rear support part"). corresponds to.) may be. Even in this case (even if part of the dash portion is the rear support portion), it can be said that the rear support portion is provided in the area between the dash portion and the power unit.

Further, in the above-described embodiment, the gearbox 44 as the "rear support portion" is arranged at a position shifted to the left in the vehicle width direction with respect to the center in the vehicle width direction, but the present invention is limited to this. not.

For example, the gearbox 44 may be arranged at a position shifted rightward in the vehicle width direction with respect to the center in the vehicle width direction. In this case, premised on the configuration of the power unit 30 of the above embodiment, the gearbox 44 will support the engine 30R (right device). In this case, the left side portions 20A, 62, 82 having the smallest cross-sectional area among the bumpers RF 20, 50, 70 are arranged on the right side of the central portions 20B, 60, 80 in the vehicle width direction. The right side portions 20C, 64, 84 having the next smallest cross-sectional area are arranged on the left side of the central portions 20B, 60, 80 in the vehicle width direction. Therefore, the first bending starting points 20D, 66, 86 that break first when colliding with the center pole are arranged on the right side, and the second bending starting points 20E, 68, 88 that break second are arranged on the left side.

Also, the rear support portion may be positioned at the center in the vehicle width direction. In this case, premised on the configuration of the power unit 30 of the above-described embodiment, the rear support portion supports the engine 30R (right device). Therefore, the configuration of the bumpers RF 20, 50, 70 is such that the first bending starting points 20D, 66, 86 that break first when colliding with the center pole are on the right, and the second bending starting points 20E, 68, 88 that break second are on the left. have.

Also, the “rear support” of the present invention is not limited to gearbox 44 . For example, it may be a master cylinder, or it may be a dash cross, which is a frame member that connects the front ends of a pair of left and right rockers (frame members extending in the vehicle front-rear direction at both ends in the vehicle width direction at the lower part of the vehicle body). good.
Also, the rear support portion is a portion (member) that can generate a reaction force with respect to the power unit. Therefore, parts (members) such as pipes and brackets that are easily deformed when receiving a collision load via the power unit do not correspond to the rear support part.

Further, in the above-described embodiment, an example was described in which the second bending starting point portions 20E, 68, 88 are provided at positions symmetrical to the first bending starting point portions 20D, 66, 86 with respect to the center in the vehicle width direction. , the invention is not limited thereto. The second bending starting point portions 20E, 68, 88 may be provided at positions opposite to the first bending starting point portions 20D, 66, 86 with respect to the center in the vehicle width direction. That is, the vehicle width direction centers of the front members 56 and 76 do not have to coincide with the vehicle width direction centers of the bumpers RF50 and 70 .

Further, in the above embodiment, as shown in FIG. 1, the first bending starting portions 20D, 66, 86 are set at positions outside the "rear supporting portion" (gearbox 44) in the vehicle width direction. , the invention is not limited to this. The first bending starting portions 20D, 66, 86 may be set at positions on the vehicle width direction inner side of the rear support portion.

S1 Vehicle front structure 10 Front side member 20 Bumper RF (bumper reinforcement)
20B, 60, 80 Central portion 20D, 66, 86 First bending starting point 20E, 68, 88 Second bending starting point 30 Power unit 30R Engine (right device)
30L transaxle (left device)
40 dash part 44 gearbox (rear support part)

Claims (1)

a pair of left and right front side members arranged on both sides of the vehicle front portion and extending along the vehicle front-rear direction;
a power unit disposed between the pair of left and right front side members and configured by connecting a right side device forming a right side portion and a left side device forming a left side portion to each other;
a dash portion located behind the power unit and in front of the vehicle compartment;
a rear support portion provided in an area between the dash portion and the power unit for supporting the right device or the left device of the power unit when the power unit moves rearward of the vehicle;
Extending along the vehicle width direction, connecting the front ends of the pair of left and right front side members, and provided at the vehicle width direction central portion and viewed from the vehicle width direction from other portions adjacent in the vehicle width direction A central portion having a large cross-sectional area, and a first bending starting point having a cross-sectional area smaller than that of the central portion and provided on the same side as the right side device or the left side device supported by the rear support portion with respect to the center in the vehicle width direction. and a second bending starting point provided on the opposite side of the right side device or the left side device supported by the rear support portion with respect to the center in the vehicle width direction and having a larger cross-sectional area than the first bending starting point. a bumper reinforcement having a
a vehicle front structure.

Images