JP2021054389A - Vehicle body front part structure - Google Patents

Abstract

To provide a vehicle body front part structure which can generate reaction force against a collision body even at the outer side of a sub frame in a vehicle width direction during a vehicle collision.SOLUTION: A vehicle body front part structure includes: side frames 10 which extend in a substantially fore and aft direction and are provided making a pair in a vehicle width direction; a bumper beam 30 which connects the front end sides of the side frames 10 and extends in a substantially vehicle width direction; sub frames 40 which are disposed below the side frames 10, extend in the substantially fore and aft direction, and are provided making a pair in the vehicle width direction; and a lower beam 50 which is disposed below the bumper beam 30, connects the front end sides of the sub frames 40, and extends in the substantially vehicle width direction. The lower beam 50 is formed extending to the outer side farther than connection parts connected to the respective sub frames 40 in the vehicle width direction.SELECTED DRAWING: Figure 1

Description

The present invention relates to a vehicle body front structure in which side frames extending substantially in the front-rear direction and provided in pairs in the vehicle width direction are connected by a bumper beam extending in the substantially vehicle width direction on the front end side of the vehicle body.

As the front structure of the vehicle body, a front side member that extends in the front-rear direction and is provided in a pair in the vehicle width direction, a front bumper infoce that connects the front ends of each front side member and extends in the vehicle width direction, and each front side member. A second member arranged below the vehicle and extending substantially in the front-rear direction and provided in a pair in the vehicle width direction, and a connecting member connecting the front ends of each second member and extending in the substantially vehicle width direction have been proposed. (See Patent Document 1). In the vehicle body front structure described in Patent Document 1, in the vehicle plan view, the front end portion of the second member is a curved portion that is inclined outward in the vehicle width direction from the rear side in the vehicle front-rear direction to the front end portion side. Is provided, and at the time of a frontal offset collision of the vehicle, the front end portion of the second member buckles inward in the vehicle width direction starting from the curved portion. As a result, the buckled portion of the front end of the second member comes into contact with the side of the drive train, and it is said that a lateral force can be generated in the vehicle.

Japanese Unexamined Patent Publication No. 2014-144714

By the way, in the vehicle body front structure described in Patent Document 1, the connecting member is not formed on the outer side in the vehicle width direction of the second member as the subframe, and the vehicle is more than the subframe with respect to the colliding body at the time of vehicle collision. No reaction force can be generated on the outside in the width direction.

The present invention has been made in view of the above circumstances, and an object of the present invention is the front of a vehicle body capable of generating a reaction force against a colliding body even outside the subframe in the vehicle width direction at the time of a vehicle collision. The purpose is to provide a subframe structure.

In order to achieve the above object, according to the present invention, a side frame extending in a substantially front-rear direction and provided in a pair in a vehicle width direction, a bumper beam extending in a substantially vehicle width direction by connecting the front end side of each side frame, and the above. A subframe that is arranged below each side frame and extends substantially in the front-rear direction and is provided in a pair in the vehicle width direction and a subframe that is arranged below the bumper beam and connects the front end side of each of the subframes and extends in the substantially vehicle width direction. A lower beam is provided, and the lower beam is provided with a vehicle body front structure formed so as to extend outward in the vehicle width direction from a connection portion with each of the subframes.

According to this vehicle body front structure, since the lower beam is arranged at the front end of the vehicle body in addition to the bumper beam, the colliding body comes into contact with the bumper beam and the lower beam at the time of a vehicle collision. As a result, the load applied to the colliding body is widely dispersed as compared with the case where the lower beam is not provided. Since the lower beam is formed so as to extend to the outside in the vehicle width direction from the connection portion with each subframe, a reaction force can be generated against the colliding body even outside the vehicle width direction from the subframe.

Even if the vehicle body front structure includes a connecting member that connects the outer side of the lower beam in the vehicle width direction with respect to the connection portion with the subframe and the rear side of the subframe with the connection portion with the lower beam. Good.

In the vehicle body front structure, the subframe is provided between the connecting portion with the lower beam and the connecting portion with the connecting member, and is bent so as to be convex upward when a collision load is applied from the front. It may have one buckling portion and a second buckling portion provided on the rear side of the connecting portion with the connecting member and bent so as to be convex downward when a collision load is applied from the front.

In the vehicle body front structure, a cross member connected to the lower part of each side frame and extending in a substantially vehicle width direction is provided, and the subframe is provided on the rear side of the second buckling portion and a collision load is applied. A third buckling portion that is bent so as to be convex upward may be provided at or near the connecting portion with the cross member.

In the vehicle body front structure, a power unit is mounted on the cross member, and the subframe is bent by the first buckling portion, the second buckling portion, and the third buckling portion. It may be arranged at a position that does not interfere with the power unit.

In the vehicle body front structure, the subframe has a crash box provided at the front end and crushes in the front-rear direction when a collision load is applied from the front, and the connecting portion of the lower beam with the connecting member is provided in the front-rear direction. It may be arranged behind the rear end of the crash box.

In the vehicle body front structure, the subframe may have a reinforcing member provided between the first buckling portion and the second buckling portion.

According to the present invention, when a vehicle collides, a reaction force can be generated against the colliding body even outside the subframe in the vehicle width direction.

It is the schematic perspective view of the vehicle body front structure which shows one Embodiment of this invention. It is a schematic perspective view of a subframe and a lower beam. It is a schematic partial plan view of a subframe and a lower beam. It is a side schematic explanatory view of the vehicle body front structure. It is explanatory drawing which shows the state which the front end of the subframe is deformed at the time of a vehicle collision. It is explanatory drawing which shows the state which the subframe is bent at the time of a vehicle collision.

1 to 6 show an embodiment of the present invention, FIG. 1 is a schematic perspective view of a vehicle body front structure, FIG. 2 is a schematic perspective view of a subframe and a lower beam, and FIG. 3 is a schematic perspective view of a subframe and a lower beam. A partial plan view, FIG. 4 is a schematic side view of the front structure of the vehicle body, FIG. 5 is an explanatory view showing a state in which the front end of the subframe is deformed at the time of a vehicle collision, and FIG. It is explanatory drawing which shows the state which was done.

As shown in FIG. 1, the vehicle body 1 is configured by, for example, assembling panel-shaped members obtained by press-molding a steel plate and joining them by spot welding or the like. The vehicle body 1 has a side frame 10 extending substantially in the front-rear direction on the front side of the vehicle and provided in pairs in the vehicle width direction, a cross member 20 connected to the lower part of each side frame 10 and extending in the substantially vehicle width direction, and a front end of each side frame 10. The bumper beam 30 that connects the sides and extends in the substantially vehicle width direction, the subframe 40 that is arranged below each side frame 10 and extends in the substantially front-rear direction and is provided in a pair in the vehicle width direction, and the front end side of each subframe 40 are connected. A lower beam 50 extending in the substantially vehicle width direction and a connecting member 60 for connecting a predetermined portion of each subframe 40 and the end side of the lower beam 50 in the vehicle width direction are provided. Further, the vehicle body 1 is provided with a radiator lower support 70 that connects the front end sides of each side frame 10 and extends substantially in the vehicle width direction, and a radiator panel 80 that extends substantially upward from both ends of the radiator lower support 70 and is provided in a pair in the vehicle width direction. And a radiator upper support 90 that connects the upper ends of the radiator panel 80 and extends in the substantially vehicle width direction. The bumper beam 30 and the lower beam 50 are arranged in front of each radiator panel 80 so that at least a part of them overlap each other in a plan view. A power unit is mounted on the cross member 20 via a mount or the like, and a suspension arm is attached to the subframe 40 via a bush, a bracket or the like.

As shown in FIG. 2, the lower beam 50 is formed so that the end side in the vehicle width direction projects outward in the vehicle width direction from the connection portion with each subframe 40. As shown in FIG. 3, the lower beam 50 extends substantially in the vehicle width direction between the connection portions with the respective subframes 40, and extends rearwardly outward in the vehicle width direction from the connection portions with the respective subframes 40. In the present embodiment, in the lower beam 50, the outer side section 51 on the outer side in the vehicle width direction including the connection portion with each subframe 40 has a closed cross section in a side view, and the inner inner section 52 inside each outer section 51 is a side surface. Make an open cross section visually. Further, in the lower beam 50, a bracket 53 connected to the radiator lower support 70 is formed so as to project rearward on the center side in the vehicle width direction.

As shown in FIG. 4, the front end of each subframe 40 is connected to the lower beam 50, and in a part of the subframe 40, the subframe 40 is inclined downward toward the rear and extends substantially horizontally to the rear as a whole. Note that FIG. 4 is a schematic view showing the positional relationship of the side frame, the subframe, and the like, and some members are omitted and some of the members shown are also shown in a simplified form. In the present embodiment, the subframe 40 has a closed cross section in the front-rear direction. The upper surface of each subframe 40 is connected to the radiator lower support 70 by spot welding between the connection portion with the lower beam 50 and the connection portion with the connecting member 60. Further, the rear end side of each subframe 40 is connected to the side frame 10, and the front and rear centers are connected to the cross member 20.

Each subframe 40 has a first buckling portion 41 provided between a connecting portion with the lower beam 50 and a connecting portion with the connecting member 60, and a first buckling portion 41 provided behind the connecting portion with the connecting member 60. It has two buckling portions 42 and a third buckling portion 43 provided on the rear side of the second buckling portion 42. When a collision load is applied to the subframe 40 from the front, the subframe 40 is bent upward at the first buckling portion 41 and convex downward at the second buckling portion 42. , It is bent upward at the third buckling portion 43. The front end side of each subframe 40 forms a crash box 44 that is crushed in the event of a vehicle collision. In this embodiment, the crash box 44 is configured to include a bead 44a. The first buckling portion 41 is arranged behind the crash box 44.

In the present embodiment, each subframe 40 is provided with a tow hook 45 between the connecting portion with the lower beam 50 and the connecting portion with the connecting member 60. Each subframe 40 is configured so that the rigidity changes in the front-rear direction at the front end of the tow hook 45, and the front end of the tow hook 45 forms the first buckling portion 41. Further, as shown in FIG. 3, in the present embodiment, a reinforcing plate portion 46 is provided inside the closed cross section of each subframe 40 corresponding to the tow hook 45, and the front end of the reinforcing plate portion 46 is also first buckled. It forms part 41. The reinforcing plate portion 46 as a reinforcing member is provided between the first buckling portion 41 and the second buckling portion 42 of the subframe 40. Since each subframe 40 has a configuration in which the rigidity changes in the front-rear direction at the front end of the tow hook 45 and / or the reinforcing plate portion 46, when an impact in the substantially front-rear direction of the vehicle is input to each subframe 40, the rigidity becomes high. Stress is concentrated on the first buckling portion 41, which is a change point, and the first buckling portion 41 becomes a bent portion that is easily bent.

Further, in the present embodiment, each subframe 40 is formed with a bead 47 on the rear side of the connecting portion with the connecting member 60. The bead 47 is formed so as to be convex downward on the upper surface of the subframe 40, and extends in the vehicle width direction. In each subframe 40, the formed portion of the bead 47 is fragile as compared with the front and rear portions thereof, and the bead 47 forms the second buckling portion 42. Further, in the present embodiment, each subframe 40 is configured so that the rigidity changes in the front-rear direction at the rear end of the reinforcing plate portion 46, and the rear end of the reinforcing plate portion 46 also has the second buckling portion 42. I'm doing it.

As shown in FIG. 4, each subframe 40 is connected to the cross member 20, and in the present embodiment, this connecting portion forms the third buckling portion 43. Each subframe 40 is inclined backward from the first buckling portion 41 to the third buckling portion. By connecting each subframe 40 to the cross member 20, the rigidity of the connecting portion is improved. Since the rigidity changes in the front-rear direction between the connection portion where the rigidity is improved and the front side thereof, when an impact in the substantially front-rear direction of the vehicle is input to each subframe 40, the third change point of the rigidity. Stress is concentrated on the buckling portion 43, and the third buckling portion 43 becomes a bent portion that is easily bent.

As shown in FIG. 3, the connecting member 60 inclines outward in the vehicle width direction from between the first buckling portion 41 and the second buckling portion 42 in each subframe 40 and extends forward, and the vehicle width of the lower beam 50. It is connected to the directional end side. In the present embodiment, the connecting member 60 is connected closer to the second buckling portion 42 between the first buckling portion 41 and the second buckling portion 42 in the subframe 40. Further, the connecting portion of the lower beam 50 with the connecting member 60 is arranged so as to be rearward of the rear end of the crash box 44.

In the vehicle body front structure configured as described above, since the bumper beam 30 and the lower beam 50 are arranged at the frontmost end of the vehicle body 1, the colliding body B first comes into contact with the bumper beam 30 and the lower beam 50 at the time of a vehicle collision. .. As a result, the load applied to the colliding body B is widely dispersed as compared with the case where the lower beam 50 is not provided. Since the lower beam 50 is formed so as to extend to the outside in the vehicle width direction from the connection portion with each subframe 40, a reaction force is generated with respect to the colliding body B also outside the vehicle width direction from the subframe 40. Can be done. Therefore, the load applied to the colliding body B at the initial stage of the collision does not increase locally.

As shown in FIG. 5, when the colliding body B moves relatively rearward after contacting with the lower beam 50, the crash box 44 on the front end side of each subframe 40 is crushed in the front-rear direction. Here, since the connecting portion of the lower beam 50 with the connecting member 60 is behind the rear end of the crash box 44, a large load may act from the colliding body B to the connecting member 60 side when the crash box 44 is crushed. Absent. In the present embodiment, each buckle is prevented from buckling by the load acting on the subframe 40 when the crash box 44 is crushed so that the first buckling portion 41, the second buckling portion 42, and the third buckling portion 43 do not buckle. The strengths of the bending portions 41, 42, and 43 are set. Therefore, in the case of a light collision in which the crash box 44 is crushed, the other parts of the subframe 40 are not deformed, and the suspension arms are not affected by the collision.

When the colliding body B moves rearward after the crash box 44 is crushed, a relatively large reaction force is generated outside the vehicle width direction of the lower beam 50 because the lower beam 50 is supported by the subframe 40 and the connecting member 60. In particular, in the present embodiment, since the outer section 51 has a closed cross section and the inner section 52 has an open cross section, the lower beam 50 is located on the center side in the vehicle width direction in which the power unit 100 or the like is arranged rearward. It is possible to effectively generate a reaction force on the outside in the vehicle width direction while suppressing the amount of penetration of the lower beam 50.

When the colliding body B moves further rearward, the subframe 40 is bent starting from the first buckling portion 41, the second buckling portion 42, and the third buckling portion 43. As shown in FIG. 6, the first buckling portion 41 is bent upward, the second buckling portion 42 is bent downward, and the third buckling portion 43 is bent upward. Here, the operation of bending each buckling portion 41, 42, 43 of the subframe 40 will be described.

When the colliding body B moves backward and is compressed in the front-rear direction, the subframe 40 is bent at three points of the first buckling portion 41, the second buckling portion 42, and the third buckling portion 43. Become a mode. In the present embodiment, since the second buckling portion 42 has a bead 47 formed so as to be convex downward on the upper surface of the subframe 40, the upper surface of the subframe 40 is bent downward due to axial compression. A convex fold occurs. As a result, when the colliding body B moves further rearward, the subframe 40 enters a buckling mode in which the second buckling portion 42 is bent downward in a convex manner. Along with the downward bending of the second buckling portion 42, rotational moments in the upward bending direction act on the first buckling portion 41 and the third buckling portion 43, respectively, and the first buckling portion 41 And the third buckling portion 43 are respectively bent upward convexly.

Since the subframe 40 inclines downward in a part of the section, a deviation occurs in the vertical direction between the front end where the impact is input and the rear end side where the reaction force with respect to the input is generated. There is. As a result, in addition to the compressive stress in the axial direction, the subframe 40 is subjected to a stress that tends to bend upwardly on the front end side located above, while it is convex downward on the rear end side located below. Stress to bend is generated. In the present embodiment, the first buckling portion 41 generates a stress for bending upwardly, and the third buckling portion 43 generates a stress for bending downward convexly. As described above, although the stress for bending downwardly is generated in the third buckling portion 43, the direction of bending upward convexly with the downward bending of the second buckling portion 42 is generated. Since the rotational moment acts, the third buckling portion 43 is bent upward convexly against the bending stress.

When the buckling portions 41, 42, and 43 are bent, the welded portion between the subframe 40 and the radiator lower support 70 is broken, and the subframe 40 is separated from the radiator lower support 70. In the present embodiment, the spot welding spot positions and the number of spot welds are set so that the subframe 40 can be accurately separated from the radiator lower support 70. By bending the buckling portions 41, 42, and 43 of the subframe 40 in this way, energy absorption at the time of collision can be achieved. Here, since the first buckling portion 41 in the subframe 40 moves rearward together with the colliding body B and the subframe 40 is held by the cross member 20 in the third buckling portion 43, the second buckling portion 40 The portion 42 moves downward while bending.

As shown in FIG. 6, when the subframe 40 is bent at each buckling portion 41, 42, 43, it collides with the subframe 40 in a vertically standing state from the first buckling portion 41 to the second buckling portion 42. Extensive contact with body B. As a result, after the subframe 40 is bent, the load applied to the colliding body B can be dispersed over a wider range.

In the present embodiment, the subframe 40 is arranged so as not to interfere with the power unit 100 and its accessories when the first buckling portion 41, the second buckling portion 42, and the third buckling portion 43 are bent. There is. Specifically, as shown in FIG. 6, when the subframe 40 rises vertically from the first buckling portion 41 to the second buckling portion 42, the rising portion of the subframe 40 is in front of the power unit 100. It is configured as. Therefore, the subframe 40 does not excessively push the power unit 100 into the room.

Further, since the connecting member 60 is connected between the first buckling portion 41 and the second buckling portion 42, the connecting member 60 affects the buckling of the second buckling portion 42 when the subframe 40 is bent. Does not affect. In the present embodiment, since the reinforcing plate portion 46 is provided between the first buckling portion 41 and the second buckling portion 42, it is effective against the load acting from the connecting member 60 to the subframe 40. Can resist.

Further, since the reinforcing plate portion 46 is provided between the first buckling portion 41 and the second buckling portion 42 in the subframe 40, the first buckling portion 41 and the second buckling portion 42 are separated from each other at the time of collision. Deformation between them is suppressed. The reinforcing plate portion 46 is provided corresponding to the tow hook 45, and the deformation mode of the subframe 40 is accurately controlled without increasing the number of parts.

In the above embodiment, the first buckling portion 41 of the subframe 40 is configured by changing the rigidity by the front ends of the tow hook 45 and the reinforcing member 46, but the tow hook 45 and the reinforcing member 46 are shown. The rigidity can be changed by one of them, or the first buckling portion 41 can be configured by a fragile portion such as a hole or a bead formed in the subframe. The configuration of the bending portion 41 can be arbitrarily changed. In particular, when the first buckling portion 41 includes a bead or a hole formed on the lower surface of the subframe 40, the first buckling portion 41 is likely to be bent upward.

Further, the second buckling portion 42 of the subframe 40 is shown to be composed of a fragile portion due to the bead 47 and a rigidity changing portion due to the rear end of the reinforcing plate portion 46. The configuration of the second buckling portion 42 can be arbitrarily changed. In the above embodiment, an example is shown in which the bead 47 formed on the upper surface of the subframe 40 makes it easy for the second buckling portion 42 to be bent downward, but for example, the first buckling portion is If the configuration is such that an upwardly convex fold is likely to occur, a buckling mode in which the second buckling portion is convex downward is realized even if the bead 47 is omitted.

Further, although the third buckling portion 43 of the subframe 40 is used as the connecting portion with the cross member 20, the third buckling portion 43 may be set in the vicinity of the connecting portion with the cross member 20. However, it can also be provided independently of the cross member 20.

Further, in the above-described embodiment, a reinforcing member is provided from the first buckling portion 41 to the second buckling portion 42 of the subframe 40, but the first buckling portion 41 to the second buckling portion 42 are provided. It is also possible to omit the reinforcing member as long as sufficient strength is ensured over the above and the bending mode of the subframe 40 is not hindered at the time of collision.

Further, in the above-described embodiment, the connecting member 60 is connected to the end side of the lower beam 50 in the vehicle width direction, but is connected to the outside of the connecting portion of the lower beam 50 with the subframe 40 in the vehicle width direction. If so, the same effect as that of the embodiment can be obtained. That is, the connecting position of the connecting member 60 can be appropriately changed according to the collision performance required for the vehicle. Furthermore, the connecting member 60 may be omitted if the collision performance required for the vehicle is satisfied.

Although the embodiments of the present invention have been described above, the embodiments described above do not limit the invention according to the claims. It should also be noted that not all combinations of features described in the embodiments are essential to the means for solving the problems of the invention.

1 Body 10 Side frame 20 Cross member 30 Bumper beam 40 Side frame 41 1st buckling part 42 2nd buckling part 43 3rd buckling part 44 Crash box 45 Tow hook 46 Reinforcing plate part 47 Bead 50 Lower frame 60 Connecting member 100 Power unit

Claims (7)

A pair of side frames that extend in the front-rear direction and are provided in the vehicle width direction,
A bumper beam that connects the front end side of each side frame and extends in the approximately vehicle width direction,
A subframe that is arranged below each side frame and extends substantially in the front-rear direction and is provided in a pair in the vehicle width direction.
It is provided with a lower beam which is arranged below the bumper beam, connects the front end side of each of the subframes, and extends in the substantially vehicle width direction.
The lower beam is a vehicle body front structure formed so as to extend outward in the vehicle width direction from a connection portion with each of the subframes. The front of the vehicle body according to claim 1, further comprising a connecting member for connecting the outside of the lower beam in the vehicle width direction with respect to the connecting portion with the subframe and the rear side of the subframe with respect to the connecting portion with the lower beam. Subframe structure. The subframe
A first buckling portion provided between the connecting portion with the lower beam and the connecting portion with the connecting member and bent upward so as to be convex when a collision load is applied from the front.
The vehicle body front structure according to claim 2, further comprising a second buckling portion provided on the rear side of the connecting portion with the connecting member and bent downward so as to be convex downward when a collision load is applied from the front. It has a cross member that is connected to the lower part of each side frame and extends in the width direction of the vehicle.
The subframe has a third buckling portion provided on the rear side of the second buckling portion and bent upward so as to be convex when a collision load is applied, at or near the connecting portion with the cross member. The vehicle body front structure according to claim 3. A power unit is mounted on the cross member.
The vehicle body front according to claim 4, wherein the subframe is arranged at a position that does not interfere with the power unit in a state of being bent by the first buckling portion, the second buckling portion, and the third buckling portion. Part structure. The subframe has a crash box provided at the front end and crushes in the front-rear direction when a collision load is applied from the front.
The vehicle body front structure according to any one of claims 3 to 5, wherein the connecting portion of the lower beam to the connecting member is arranged behind the rear end of the crash box in the front-rear direction. The vehicle body front structure according to any one of claims 3 to 6, wherein the subframe has a reinforcing member provided between the first buckling portion and the second buckling portion.

Images