JP7152292B2 - 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 upon collision with a center pole.

A vehicle front structure according to claim 1 includes a pair of left and right front side members arranged on both sides of a vehicle front portion and extending along the vehicle front-rear direction; A metal bumper reinforcement that connects the front ends of a pair of left and right front side members to each other; and a right side device and a left side that are arranged between the pair of left and right front side members and behind the bumper reinforcement to form a right side portion of the bumper reinforcement. A power unit configured by connecting a left side device that constitutes a part to each other, a dash portion located behind the power unit and in front of the passenger compartment, and provided in an area between the dash portion and the power unit. a rear support portion that supports the right device or the left device of the power unit when the power unit moves rearward of the vehicle, wherein the bumper reinforcement is provided at the center in the vehicle width direction and has a predetermined strength. and a center portion formed of a material having a strength lower than the predetermined strength, 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 first low-strength portion 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 lower strength than the predetermined strength and the first low-strength portion. and a second low-strength portion formed of a material having a strength higher than that of the strength portion , wherein the central portion and the first low-strength portion are joined, and the central portion and the second low-strength portion is joined with .

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 metal bumper reinforcement that connects the front ends of the pair of left and right front side members extends along the vehicle width direction. is arranged between a 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.

The bumper RF is provided with a central portion made of a material having a predetermined strength at the center in the vehicle width direction. A first low-strength portion made of a material having a strength lower than a predetermined strength 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. Furthermore, a material having a strength lower than a predetermined strength and higher than the strength of the first low-strength portion is formed 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. A second weakened portion is provided.

Here, when the center pole collides, if the boundary portion between the second low-strength portion and the center portion on the opposite side of the right device supported by the rear support portion or the left device is the first bending point, the right side Since the device or the left device in which the bending starting point transmits the collision load is different from the device supported by the rear support portion, the shear input to the connecting portion between the left device and the right device increases. 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 bending starting point moves toward the passenger compartment. There is a risk that the amount of deformation of the dash portion will increase due to the load being transmitted to the dash.

Therefore, in the vehicle front portion structure of the present invention, the material strength of each portion constituting the bumper RF is set so as to decrease in the order of the central portion, the second low-strength portion, and the first low-strength portion. Therefore, the bending strength of the bumper RF also decreases in the order of the central portion, the second low-strength portion, and the first low-strength portion. As a result, when the center pole collides, the boundary portion between the central portion and the first low-strength portion (hereinafter referred to as the first bending starting portion) breaks first, and then the boundary portion between the central portion and the second low-strength portion ( hereinafter referred to as a second folding starting point) is set to fold. In addition, since the position of the first bending starting point where the first bending occurs 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 point at the time of collision with the center pole is set. A starting point is configured to transfer the crash load to the side of the right or left device that is supported by the rear support.

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 at the first bend starting point increases. 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.

The vehicle front structure according to claim 2 includes 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, and a pair of left and right front side members extending along the vehicle width direction, A metal bumper reinforcement that connects the front ends of a pair of left and right front side members to each other; and a right side device and a left side that are arranged between the pair of left and right front side members and behind the bumper reinforcement to form a right side portion of the bumper reinforcement. A power unit configured by connecting a left side device that constitutes a part to each other, a dash portion located behind the power unit and in front of the passenger compartment, and provided in an area between the dash portion and the power unit. a rear support portion that supports the right device or the left device of the power unit when the power unit moves rearward of the vehicle; A central portion having a thickness and a first lower plate having a plate thickness smaller than the predetermined plate thickness 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 force-bearing portion, and a plate of the first low force-bearing portion 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 thickness smaller than the predetermined plate thickness. and a second low strength portion having a plate thickness greater than the thickness.

In the vehicle front portion structure according to claim 2, 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 metal bumper reinforcement that connects the front ends of the pair of left and right front side members extends along the vehicle width direction. is arranged between a 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.

Further, the bumper RF is provided with a central portion having a predetermined plate thickness at the center in the vehicle width direction. Further, a first low strength portion having a plate thickness smaller than a predetermined plate thickness 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. Further, the second low strength portion has a plate thickness smaller than a predetermined plate thickness and larger than the plate thickness of the first low strength portion 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. Two low-strength sections are provided. In this way, the plate thickness of each part constituting the bumper RF is set so as to decrease in the order of the central portion, the second low-strength portion, and the first low-strength portion, so that the bending yield strength also decreases in this order. It's becoming

With the above configuration, when the center pole collides, the boundary portion between the central portion and the first low-yield-strength portion (hereinafter referred to as the first bending starting point portion) breaks first, and then the boundary portion between the central portion and the second low-yield-strength portion. (hereinafter referred to as a second folding starting point) is set to fold. In addition, since the position of the first bending starting point where the first bending occurs 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 point at the time of collision with the center pole is set. A starting point is configured to transfer the crash load to the side of the right or left device that is supported by the rear support. Therefore, cracking of the power unit is suppressed and the reaction force from the power unit to the bumper RF at the first bend starting point increases, so that the bumper RF is more likely to break 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 vehicle front structure of claim 1, 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. .

According to the vehicle front structure of claim 2, 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 according to 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; (A) is a schematic plan view showing a bumper RF. (B) is a diagram showing bending strength characteristics of the bumper RF shown in (A). (A) is a sectional view taken along the line 6A-6A of FIG. 5(A). (B) is a sectional view taken along line 6B-6B of FIG. 5(A). (C) is a sectional view taken along line 6C-6C of FIG. 5(A). (A) is a schematic plan view showing a bumper RF of the vehicle front structure according to the second embodiment. (B) is a diagram showing bending strength characteristics of the bumper RF shown in (A). (A) is a cross-sectional view taken along line 8A-8A of FIG. 7(A). (B) is a cross-sectional view taken along line 8B-8B of FIG. 7(A). (C) is a sectional view taken along line 8C-8C of FIG. 7(A). (A) is a diagram showing bending resistance characteristics of a bumper RF in a vehicle front structure according to a comparative example. (B) 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 6C and 9. FIG.

An arrow FR, an arrow UP, and an arrow LH shown in each figure indicate the front direction, the upward direction, 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 of this embodiment includes a pair of left and right front side members 10 arranged on both sides of the vehicle front. 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.

Further, the vehicle front structure includes a bumper RF 20 made of metal (made of steel plate in this embodiment). 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 that extends uniformly and linearly in the vehicle width direction is schematically illustrated, the cross-sectional area of the bumper RF 20 seen from the vehicle width direction is the largest at the center in the vehicle width direction. It is configured to become smaller toward the outside in the width direction. Also, the bumper RF 20 may have a shape in which both side portions in the vehicle width direction are obliquely bent toward the vehicle rear side, that is, the bumper RF 20 may have an arcuate shape projecting toward the vehicle front side as a whole. A more detailed configuration of the bumper RF 20 will be described later.

The vehicle front structure 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 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(A) to 6(C).

As shown in FIG. 5A, the bumper RF 20 includes a central portion 46 provided in the center in the vehicle width direction, and a left side as a "first low-strength portion" provided on the left side of the central portion 46 in the vehicle width direction. and a right side portion 50 as a “second low-strength portion” provided on the right side of the central portion 46 in the vehicle width direction.

6A to 6C are longitudinal sectional views of the left side portion 48, the central portion 46, and the right side portion 50 of the bumper RF 20 shown in FIG. 5A as viewed from the left side in the vehicle width direction. It is shown.

As shown in FIG. 6B, the central portion 46 of the bumper RF 20 includes a rear member 52 located on the rear side of the vehicle and a front member 54 located on the front side of the vehicle.

The rear member 52 of the central portion 46 includes a rear body portion 52A having a substantially U-shaped cross section that opens toward the vehicle front side. Further, a rear upper flange 52B extends upward toward the vehicle from the upper end of the rear body portion 52A, and a rear lower flange 52C extends downward toward the vehicle from the lower end of the rear body portion 52A. there is For this reason, the rear member 52 is formed to have a substantially hat-shaped cross section that is open to the front side of the vehicle.

The front member 54 of the central portion 46 is formed in the shape of a flat plate whose plate thickness direction is the vehicle front-rear direction. ing. In addition, a front upper flange 54B extends from the upper end portion of the front body portion 54A toward the upper side of the vehicle, and the front upper flange 54B is superimposed on the rear upper flange 52B of the rear member 52 and spot welding or the like is performed. joined by Further, a front lower flange 54C extends downward from the lower end of the front main body 54A, and the front lower flange 54C is overlapped with the rear lower flange 52C of the rear member 52, and spot welding or the like is performed. joined by Thereby, the central portion 46 of the bumper RF 20 of the present embodiment has a closed cross-sectional structure (hollow structure).

As shown in FIG. 6A, the left side portion 48 of the bumper RF 20 includes a rear member 56 having a substantially hat-shaped cross section located on the rear side of the vehicle and a front member 58 having a flat plate shape located on the front side of the vehicle. is composed of The rear member 56 includes a rear main body portion 56A having a substantially U-shaped cross section that is open to the vehicle front side, a rear upper flange 56B that extends upward from the upper end portion of the rear main body portion 56A, and a rear upper flange 56B. A rear lower flange 56C extends from the lower end portion of the rear main body portion 56A toward the vehicle lower side. The front member 58 includes a front body portion 58A that closes the opening of the rear member 56, a front upper flange 58B that extends upward from the upper end of the front body portion 58A, and a lower end portion of the front body portion 58A. and a front lower flange 58C extending downward of the vehicle. The rear upper flange 56B and the front upper flange 58B are overlapped and joined by welding or the like, and the rear lower flange 56C and the front lower flange 58C are overlapped and joined by welding or the like. As a result, the left side portion 48 has a closed cross-sectional structure (hollow structure).

Here, the dimension in the vehicle front-rear direction of the rear main body portion 56A of the rear member 56 in the left side portion 48 is the vehicle front-rear dimension of the rear main body portion 52A of the rear member 52 in the central portion 46 (see FIG. 6B). It is set smaller than the direction dimension. Thereby, the cross-sectional area of the left side portion 48 is smaller than the cross-sectional area of the central portion 46 .

As shown in FIG. 6C, the right side portion 50 of the bumper RF 20 has the same configuration as the left side portion 48 (see FIG. 6A) (as will be described later, the material strength of the left side portion is 48). That is, a closed cross-sectional structure is formed by a rear member 60 having a substantially hat-shaped cross section and a front member 62 having a flat plate shape. The rear member 60 includes a rear body portion 60A, a rear upper flange 60B and a rear lower flange 60C, and the front member 62 includes a front body portion 62A, a front upper flange 62B and a front lower flange 62C. and Here, the dimension in the vehicle front-rear direction of the rear body portion 60A of the rear member 60 in the right side portion 50 is the vehicle front-rear dimension of the rear body portion 52A of the rear member 52 in the central portion 46 (see FIG. 6B). It is set smaller than the direction dimension. As with the left side portion 48 , the right side portion 50 has a smaller cross-sectional area than the central portion 46 .

Moreover, as described above, the bumper RF 20 is configured such that the cross-sectional area seen in the vehicle width direction is the largest at the center in the vehicle width direction and decreases toward the outside in the vehicle width direction. Specifically, the dimensions of the rear body portions 52A, 56A, and 60A in the vehicle front-rear direction are the largest at the center in the vehicle width direction, and decrease toward the outside in the vehicle width direction. 1 to 5A, illustration of the rear members 52, 56, 60 and the front members 54, 58, 62 is omitted.

Returning to FIG. 5A, the central portion 46, the left portion 48, and the right portion 50 are made of metal materials (steel plates in this embodiment) having different strengths. Specifically, the central portion 46 of the bumper RF 20 is made of a material having the highest strength. Further, the left side portion 48 is made of a material having the lowest strength among the bumpers RF20. Further, the right side portion 50 is formed of a material having a strength lower than that of the central portion 46 and higher than that of the left side portion 48 .

As described above, the central portion 46, the left side portion 48, and the right side portion 50, which have different material strengths, are joined by welding or the like to form the bumper RF20. As a result, the front side members 54, 58, 62 (see FIGS. 6A to 6C) of the central portion 46, the left side portion 48, and the right side portion 50 constitute the front side of the bumper RF20. Similarly, rear members 52, 56, and 60 (see FIGS. 6A to 6C) of the central portion 46, the left portion 48, and the right portion 50 constitute the rear side of the bumper RF20. As an example of materials constituting each part of the bumper RF 20, the central part 46 is made of ultra-high-tensile steel (ultra-high-tensile steel plate), the right side part 50 is made of high-tensile material (high-tensile steel plate), and the left side part 48 is made of ordinary steel plate. good.

In this manner, the material strength of each portion constituting the bumper RF 20 is set so as to decrease in the order of the central portion 46, the right side portion 50, and the left side portion 48. , left side 48 . The bending strength of each part of the bumper RF20 will be described in detail below.

FIG. 5(B) is a graph showing the bending strength characteristic with respect to the position of the bumper RF 20 in the vehicle width direction. As shown in FIG. 5B, the bending strength of the bumper RF20 is highest at the center in the vehicle width direction and decreases toward the outside in the vehicle width direction. This is because the cross-sectional area seen in the vehicle width direction decreases toward the outside in the vehicle width direction as described above.

In addition, in the center portion 46, the bending strength decreases continuously from the center in the vehicle width direction toward the outside, but at the boundary portion between the center portion 46 and the left side portion 48, the decrease is not continuous but abrupt. Bending strength is decreased. This is because the material strength of the left side portion 48 is lower than that of the central portion 46 .

Furthermore, the bending resistance is abruptly lowered at the boundary between the central portion 46 and the right side portion 50 as well. This is due to the material strength of the right side portion 50 being lower than that of the central portion 46 . The bending strength of the boundary portion between the central portion 46 and the left side portion 48 is lower than the bending strength of the boundary portion between the central portion 46 and the right side portion 50 . That is, there is a proof stress difference (indicated by arrow D) between the two. This is because the material strength of the left side portion 48 is lower than that of the right side portion 50 .

With the above structure, the boundary portion between the central portion 46 and the left side portion 48 of the bumper RF 20 is the most likely to bend, and the first bending starting portion 64 (FIGS. 1 to 5 (FIGS. 1 to 5 ( A) see). A boundary portion between the central portion 46 and the right side portion 50 constitutes a second folding starting portion 66 (see FIGS. 1 to 5A) that is folded next to the first folding starting portion 64 .

In other words, the bumper RF 20 has two bending starting points (a first bending starting point 64 and a second bending starting point 66) with the central portion 46 interposed therebetween. The bending strength of the first bending starting point 64 is set lower than the bending strength of the second bending starting point 66 by the difference D in the bending strength. As a result, the first bending starting point 64 of the bumper RF 20 is controlled to break first when it collides with the center pole, and the second bending starting point 66 is controlled to break after the first bending starting point 64. there is

<Action and effect>
Next, the operation and effects of this embodiment will be described in comparison with the comparative example shown in FIGS. 9A and 9B.

In the vehicle front structure according to the comparative example, the bumper RF 100 is made of a single material, has the same material strength across the vehicle width direction, and has a cross-sectional area viewed from the vehicle width direction outward in the vehicle width direction. (Bumper RF100 uniformly extending in the vehicle width direction is schematically illustrated in FIG. 9B). Therefore, as shown in FIG. 9(A), the shape of the bending resistance characteristic diagram is a continuous and gentle mountain shape, and there is no portion where the bending resistance is abruptly lowered. Therefore, in the event of a collision with the center pole, there is a possibility that the portion where the bending resistance is lower than the center portion of the vehicle (the position corresponding to the middle of the mountain in the bending resistance characteristic diagram) may become the starting point of bending.

As shown in FIG. 9B, if the engine 30R were to break at the breakage starting point 100A when colliding with the pole P, the engine 30R would not be supported by the gearbox 44. 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 vehicle front-rear direction. 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.

As shown in FIGS. 1 to 5A, the bumper RF 20 includes a central portion 46 provided at the central portion in the vehicle width direction and formed of a material having a predetermined strength, and a central portion 46 having a lower strength than the central portion 46. There is a left side 48 made of material and a right side 50 made of a material having a strength lower than that of the central section 46 and higher than that of the left side 48 . Here, the left side portion 48 is provided on the same side as the transaxle 30L supported by the gearbox 44 with respect to the center in the vehicle width direction. Further, the right side portion 50 is provided on the side opposite to the transaxle 30L supported by the gearbox 44 with respect to the center in the vehicle width direction.

As a result, in the vehicle front structure of the present embodiment, as shown in FIGS. 2 and 3, the boundary portion between the central portion 46 and the left side portion 48 at the time of collision with the center pole serves as the first bending starting portion 64 that is first bent. , the position of the first bending starting point 64 is set so as to transmit the collision load to the device on the side supported by the gear box 44, out of the engine 30R and the transaxle 30L. Therefore, in the vehicle front structure 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. 2, the bumper RF 20 does not break at the center position in the vehicle width direction where the pole abuts. Then, it breaks at the first bending starting point 64 that constitutes the boundary portion with the left side portion 48 where the material strength is the lowest and the bending resistance is set to be the lowest. Next, as shown in FIG. 3 , the first bending starting portion 64 of bumper RF 20 transmits the collision load (indicated by arrow F) to transaxle 30L of power unit 30 . 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 supported by the gearbox 44 and the device to which the first bending starting point 64 transmits the collision load are the same device (the transaxle 30L), the connecting portion 34 between the engine 30R and the transaxle 30L does not increase the shear input generated at As a result, power unit cracking is suppressed.

Furthermore, by suppressing power unit cracking, the reaction force from the power unit 30 to the bumper RF 20 at the first bending starting point 64 (the reaction force against the force indicated by arrow F in FIG. 3) increases. Therefore, as shown in FIG. 3, the bumper RF 20 is likely to be bent at the second point. Here, the second fold is between the central portion 46 and the right portion 50, which has lower material strength (lower bending resistance) than the central portion 46 and higher material strength (higher bending resistance) than the left portion 48. occurs at the second bending starting point 66 that constitutes the boundary of the . When the second bending starting portion 66 is bent, as shown in FIG. 4, the power unit 30 is pushed rearward in the range between the first bending starting portion 64 and the second bending starting portion 66 of 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.

Thus, in this embodiment, the amount of deformation of the passenger compartment can be reduced by controlling the bending position and bending order of the bumper RF20 without increasing the mass and components of the bumper RF20.

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 64 of the bumper RF 20 bends and displaces toward the power unit 30, the collision load is transmitted from the bumper RF 20 to the power unit 30 via the cooling unit and the like.

[Second embodiment]
Next, a second embodiment of the present invention will be described with reference to FIGS. 7(A) to 8(C). It should be noted that structures similar to those of the first embodiment are denoted by the same reference numerals, and description thereof will be omitted as appropriate.

As shown in FIG. 7A, the bumper RF 70 of the vehicle front structure according to the present embodiment includes a central portion 72 provided at the center in the vehicle width direction, and It includes a left side portion 74 as a “first low strength portion” and a “second low strength portion” right side portion 76 provided on the right side of the central portion 72 in the vehicle width direction. The central portion 72, the left portion 74, and the right portion 76 are made of the same metal material (steel plate in this embodiment). Although the bumper RF70 that extends uniformly and linearly in the vehicle width direction is schematically illustrated, the bumper RF70 has a shape in which both sides in the vehicle width direction are obliquely bent toward the rear side of the vehicle, that is, as a whole It may have an arcuate shape that protrudes toward the front side of the vehicle.

8(A) to 8(C) are longitudinal cross-sectional views of a left side portion 74, a central portion 72, and a right side portion 76 of the bumper RF 70 shown in FIG. 7(A) as viewed from the left side in the vehicle width direction. It is shown.

As shown in FIG. 8B, the central portion 72 of the bumper RF 70 includes a rear member 78 having a substantially hat-shaped cross section located on the rear side of the vehicle and a front member 80 having a flat plate shape located on the front side of the vehicle. is composed of Specifically, the rear member 78 includes a rear main body portion 78A having a substantially U-shaped cross section that is open to the front side of the vehicle, and a rear main body portion 78A that extends upward from the upper end portion of the rear main body portion 78A. It is provided with an upper flange 78B and a rear lower flange 78C extending from the lower end portion of the rear main body portion 78A toward the vehicle lower side. The front member 80 includes a front body portion 80A that closes the opening of the rear member 78, a front upper flange 80B that extends upward from the upper end of the front body portion 80A, and a lower end portion of the front body portion 80A. and a front lower flange 80C extending downward of the vehicle. The rear upper flange 78B and the front upper flange 80B are overlapped and joined by welding or the like, and the rear lower flange 78C and the front lower flange 80C are overlapped and joined by welding or the like. Thereby, the central portion 72 has a closed cross-sectional structure (hollow structure).

As shown in FIG. 8A, the left side portion 74 of the bumper RF 70 includes a rear member 82 having a substantially hat-shaped cross section located on the rear side of the vehicle and a front member 84 having a flat plate shape located on the front side of the vehicle. is composed of The rear member 82 includes a rear main body portion 82A having a substantially U-shaped cross section that is open to the vehicle front side, a rear upper flange 82B that extends upward from the upper end portion of the rear main body portion 82A, and a rear upper flange 82B. A rear-side lower flange 82C extends downward from the lower end of the rear-side body portion 82A. The front member 84 includes a front body portion 84A that closes the opening of the rear member 82, a front upper flange 84B that extends upward from the upper end of the front body portion 84A, and a lower end portion of the front body portion 84A. and a front lower flange 84C extending to the vehicle lower side. The rear upper flange 82B and the front upper flange 84B are overlapped and joined by welding or the like, and the rear lower flange 82C and the front lower flange 84C are overlapped and joined by welding or the like. As a result, the left side portion 74 has a closed cross-sectional structure (hollow structure).

Here, the dimension in the vehicle front-rear direction of the rear body portion 82A of the rear member 82 in the left side portion 74 is the vehicle front-rear dimension of the rear body portion 78A of the rear member 78 in the central portion 72 (see FIG. 8B). It is set smaller than the direction dimension. Thereby, the cross-sectional area of the left side portion 74 is smaller than the cross-sectional area of the central portion 72 .

As shown in FIG. 8C, the right side portion 76 of the bumper RF 70 includes a rear member 86 having a substantially hat-shaped cross section located on the rear side of the vehicle and a front member 88 having a flat plate shape located on the front side of the vehicle. is composed of The rear member 86 includes a rear main body portion 86A having a substantially U-shaped cross section that is open to the front side of the vehicle, a rear upper flange 86B that extends upward from the upper end portion of the rear main body portion 86A, A rear lower flange 86C extends downward from the lower end of the rear main body 86A. The front member 88 includes a front body portion 88A that closes the opening of the rear member 86, a front upper flange 88B that extends upward from the upper end of the front body portion 88A, and a lower end portion of the front body portion 88A. and a front lower flange 88C extending downward of the vehicle. The rear upper flange 86B and the front upper flange 88B are overlapped and joined by welding or the like, and the rear lower flange 86C and the front lower flange 88C are overlapped and joined by welding or the like. As a result, the right side portion 76 has a closed cross-sectional structure (hollow structure).

Here, the dimension in the vehicle front-rear direction of the rear body portion 86A of the rear member 86 in the right side portion 76 is the vehicle front-rear dimension of the rear body portion 78A of the rear member 78 in the central portion 72 (see FIG. 8B). It is set smaller than the direction dimension. Thereby, the cross-sectional area of the right side portion 76 is smaller than the cross-sectional area of the central portion 72 .

Moreover, as described above, the bumper RF 70 is configured such that the cross-sectional area when viewed in the vehicle width direction is the largest at the center in the vehicle width direction and decreases toward the outside in the vehicle width direction. Specifically, the dimensions of the rear body portions 78A, 82A, and 86A in the vehicle front-rear direction are the largest at the central portion in the vehicle width direction, and decrease toward the outside in the vehicle width direction. It should be noted that the illustration of the rear members 78, 82, 86 and the front members 80, 84, 88 is omitted in FIG. 7(A) described above.

The plate thickness of each part of the bumper RF 70 is the plate thickness t1 of the central portion 72 (see FIG. 8B), the plate thickness t2 of the right side portion 76 (see FIG. 8C), and the plate thickness t3 of the left side portion 74 (see FIG. 8C). (See FIG. 8A). As a result, the bending strength of each portion of the bumper RF 70 is also set to decrease in the order of the central portion 72 , the right side portion 76 and the left side portion 74 .

As described above, the central portion 72, the left side portion 74, and the right side portion 76 having different plate thicknesses t1, t2, and t3 are joined at their ends in the vehicle width direction by welding or the like to form the bumper RF70. Thereby, the front side members 80 , 84 , 88 of the central portion 72 , the left side portion 74 , and the right side portion 76 constitute the front side of the bumper RF 70 . Similarly, rear side members 78 , 82 , 86 of the central portion 72 , the left side portion 74 , and the right side portion 76 constitute the rear side of the bumper RF 70 .

In this embodiment, the rear member 78 and the front member 80 of the central portion 72 have the same plate thickness (t1), but the present invention is not limited to this. The thickness of the rear member 78 and the front member 80 of the central portion 72 may be different. Similarly, the thickness of the rear member 82 and the front member 84 of the left side portion 74 may be different, and the thickness of the rear member 86 and the front member 88 of the right side portion 76 may be different. The thickness of each part of the bumper RF 70 may be set so that the bending strength of each part of the bumper RF 70 decreases in the order of the central part 72 , the right side part 76 and the left side part 74 .

FIG. 7(B) is a graph showing the bending strength characteristic with respect to the position of the bumper RF20 in the vehicle width direction. As shown in FIG. 7(B), the bending strength of the bumper RF20 is highest at the center in the vehicle width direction and decreases toward the outside in the vehicle width direction. This is because the cross-sectional area seen in the vehicle width direction decreases toward the outside in the vehicle width direction as described above.

In addition, in the center portion 72, the bending resistance decreases continuously from the center in the vehicle width direction toward the outside, but at the boundary portion between the center portion 72 and the left side portion 74, the decrease is not continuous but abrupt. Bending strength is decreased. This is because the thickness t3 of the left side portion 74 is smaller than the thickness t1 of the central portion 72 .

Furthermore, the bending resistance is abruptly lowered at the boundary between the central portion 72 and the right side portion 76 as well. This is because the thickness t2 of the right side portion 76 is smaller than the thickness t1 of the central portion 72 . The bending strength of the boundary portion between the central portion 72 and the left side portion 74 is lower than the bending strength of the boundary portion between the central portion 72 and the right side portion 76 . That is, there is a proof stress difference (indicated by arrow E) between the two. This is because the thickness t3 of the left side portion 74 is smaller than the thickness t2 of the right side portion 76 .

With the above structure, the boundary portion between the center portion 72 and the left side portion 74 of the bumper RF 20 is the most likely to be bent, and the first bend starting portion 90 (see FIG. 7A) that is the first to break when colliding with the center pole. ). A boundary portion between the central portion 72 and the right side portion 76 constitutes a second folding starting portion 92 (see FIG. 7A) that folds next to the first folding starting portion 90 .

<Action and effect>
Next, the operation and effects of this embodiment will be described.

In this embodiment, as shown in FIGS. 7A and 8A to 8C, the bumper RF 70 has a central portion 72 having a predetermined plate thickness t1 and a plate thickness of the central portion 72 A left side portion 74 having a thickness t3 smaller than t1 and a right side portion 76 having a thickness t2 smaller than the thickness t1 of the central portion 72 and larger than the thickness t1 of the left side portion 74 are provided. there is Here, the left side portion 74 is provided on the same side as the transaxle 30L supported by the gearbox 44 (see FIGS. 1 to 4) with respect to the center in the vehicle width direction. Further, the right side portion 76 is provided on the side opposite to the transaxle 30L supported by the gearbox 44 with respect to the center in the vehicle width direction.

As a result, when the center pole collides, the bumper RF 70 does not break at the center position in the vehicle width direction where the pole abuts. It is broken at the first bending starting point 90 which has a small plate thickness t3 and forms a boundary portion with the left side portion 74 where the bending strength is set to be the lowest. Next, the first bending starting portion 90 of the bumper RF 70 transmits the collision load to the transaxle 30L of the power unit 30, like the first bending starting portion 64 (see FIG. 3) in the first embodiment. 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 supported by the gearbox 44 and the device to which the first bending starting point 90 transmits the collision load are the same device (the transaxle 30L), the connecting portion 34 between the engine 30R and the transaxle 30L does not increase the shear input generated at As a result, power unit cracking is suppressed.

Furthermore, by suppressing power unit cracking, the reaction force from the power unit 30 to the bumper RF 70 at the first bending starting point 90 increases. Therefore, the bumper RF 70 is likely to be bent at the second point. Here, the second fold is the center portion 72 and the right side portion having a plate thickness t2 smaller than the center portion 72 (lower bending resistance) and larger than the left side portion 74 (high bending resistance). It occurs at the second bend starting point 92 that constitutes the boundary portion with 76 . When the second bending starting point 92 is bent, the power unit 30 is pushed rearward of the vehicle in the range between the first bending starting point 90 and the second bending starting point 92 in the bumper RF 70 (face pushing). 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.

Thus, in this embodiment, the amount of deformation of the passenger compartment can be reduced by controlling the bending position and bending order of the bumper RF70 without increasing the mass and components of the bumper RF70.

[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 48 , 74 of the bumpers RF 20 , 70 having the lowest bending resistance are arranged on the right side of the central portions 46 , 72 in the vehicle width direction. Moreover, the right side portions 50 and 76 having the next lowest bending strength are arranged on the left side of the central portions 46 and 72 in the vehicle width direction. Therefore, the first bending starting points 64 and 90 that break first when colliding with the center pole are arranged on the right side, and the second bending starting points 66 and 92 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 bumpers RF 20, 70 are configured to have the first bending starting points 64, 90 on the right side, which are bent first when colliding with the center pole, and the second bending starting points 66, 92, which are bent second, on the left side.

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 in which the first bending starting point portions 64 and 90 are provided at positions symmetrical to the second bending starting point portions 66 and 92 with respect to the center in the vehicle width direction has been described. It is not limited to this. The second bending starting point portions 66 and 92 may be provided at positions opposite to the first bending starting point portions 64 and 90 with respect to the center in the vehicle width direction.

Further, in the above-described embodiment, an example was described in which the first bending starting portions 64 and 90 were set at positions outside the "rear supporting portion" (gearbox 44) in the vehicle width direction, but the present invention is not limited to this. is not limited to The first bending starting portions 64 and 90 may be set at positions on the vehicle width direction inner side of the rear support portion.

10 front side member 20 bumper RF (bumper reinforcement)
30 power unit 30R engine (right side device)
30L transaxle (left device)
40 dash part 44 gearbox (rear support part)
46 central part 48 left part (first low-strength part)
50 Right side (second low strength part)
72 Central portion 74 Left side (first low strength portion)
76 Right part (second low strength part)
t1, t2, t3 plate thickness

Claims (2)

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 metal bumper reinforcement that extends along the vehicle width direction and connects the front ends of the pair of left and right front side members;
a power unit disposed between the pair of left and right front side members and behind the vehicle of the bumper reinforcement, and configured by connecting a right side device constituting a right side portion and a left side device constituting 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;
with
The bumper reinforcement includes a center portion provided at the center in the vehicle width direction and formed of a material having a predetermined strength, and 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 first low-strength portion provided on the side and formed of a material having a strength lower than the predetermined strength; and a second low-strength portion formed of a material having a strength lower than the predetermined strength and higher than the strength of the first low-strength portion,
The central portion and the first low-strength portion are joined, and the central portion and the second low-strength portion are joined,
Vehicle front structure. 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 metal bumper reinforcement that extends along the vehicle width direction and connects the front ends of the pair of left and right front side members;
a power unit disposed between the pair of left and right front side members and behind the vehicle of the bumper reinforcement, and configured by connecting a right side device constituting a right side portion and a left side device constituting 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;
with
The bumper reinforcement is provided at the center in the vehicle width direction and has a predetermined plate thickness, and is provided on the same side as the right device or the left device supported by the rear support portion with respect to the center in the vehicle width direction. a first low-strength portion having a plate thickness smaller than the predetermined plate thickness; a second low-strength portion having a thickness smaller than a predetermined thickness and greater than the thickness of the first low-strength portion;
Vehicle front structure.

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