JP4241071B2 - Front body structure of automobile - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a front body structure of an automobile.
[0002]
[Prior art]
In general, the front body structure of an automobile is made up of a front side member disposed in the longitudinal direction of the vehicle body on both sides in the vehicle width direction of the front portion of the vehicle, and a subframe on the lower side of the front side member on which a power unit is mounted. Composed. For example, as in the prior art described in Patent Literature 1, a front side member and a subframe are connected to each other at the front end, the rear end, and an intermediate portion of the subframe.
[0003]
[Patent Document 1]
Japanese Patent Laid-Open No. 2002-255059
[Problems to be solved by the invention]
However, in the case of such a vehicle body structure, the front side member and the sub frame are coupled so that the coupling rigidity is substantially equal at each of the six coupling portions including the front end, the rear end, and the intermediate portion of the sub frame. Therefore, when a load is applied to such a vehicle body from the front, the rigidity is maintained at each connecting portion, and axial crushing (collapse deformation) hardly occurs in both the front side member and the sub frame. There was a problem of low absorption efficiency.
[0005]
Therefore, the present invention has been made in view of such conventional problems, and provides a front vehicle body structure for a vehicle that can disperse a load applied from the front of the vehicle body and can significantly improve the energy absorption efficiency according to the load. The purpose is to do.
[0006]
[Means for Solving the Problems]
In the present invention, the front side members are disposed in the longitudinal direction of the vehicle body on both sides in the vehicle body width direction, and the subframe is disposed below the front side member. The front end of the side member is joined to the lower surface of the rear part of the front side member, and the middle part of the front and rear end parts is joined to the lower surface of the front part of the front side member and the middle part of the rear part. In the front body structure of an automobile, the front end portion of the subframe and the front lower surface of the front side member are coupled by a first coupling portion, and the middle portion of the subframe and the middle of the front side member are coupled. coupled by a second coupling portion coupling the lower surface, the intensity of the first coupling part is rather low than the strength of the second coupling portion, said first The coupling portion connects the first and second attachment portions to the first attachment portion attached to the front end portion of the subframe, the second attachment portion attached to the front lower surface of the front side member, and the first attachment portion. and a connecting portion, the thickness of the connecting portion, and a thin Kunar so than the thickness of said first and second mounting portions.
[0007]
【The invention's effect】
According to the present invention, the strength of the first coupling portion that couples the front end portion of the subframe and the front lower surface of the front side member is the first strength that couples the intermediate portion of the subframe and the intermediate portion lower surface of the front side member. When the load is applied from the front of the vehicle body, the connection between the front end of the subframe and the front lower surface of the front side member is broken and separated when a load is applied from the front of the vehicle body. Therefore, the load can be distributed and transmitted to the front side member side and the subframe side, and axial crushing can be caused between the front side member and the subframe. Thus, it is possible to provide a front body structure of an automobile that can significantly improve the energy absorption efficiency according to the load.
At this time, in the present invention, since the connecting portion of the first coupling portion is formed thinner than the thickness of the first and second mounting portions, when a load is applied from the front of the vehicle body, the connecting portion is damaged, The coupling between the front end portion of the subframe and the front lower surface of the front side member by the first coupling portion can be broken and separated, and the load is efficiently distributed to the front side member side and the subframe side. Can be transmitted.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, reference examples of the present invention will be described in detail with reference to the drawings.
[0009]
1 to 4 show a reference example of a front body structure of an automobile according to the present invention, FIG. 1 is a cross-sectional view showing a schematic configuration of the front body structure, and FIG. 2 is a top view of the front body structure in FIG. FIG. 3 is a cross-sectional view showing the behavior of the front vehicle body structure at the initial stage when a load is input from the front of the vehicle body, and FIG. 4 is a front vehicle body at the final stage when the load is input from the front of the vehicle body. It is sectional drawing which shows the behavior of a structure.
[0010]
The front vehicle body structure of this reference example corresponds to the front portion of the vehicle body shown in FIGS. 1 and 2, that is, a front compartment 1 portion in which a power unit such as an engine or a motor (not shown) is accommodated. A dash panel 2 separates the vehicle compartment 3.
[0011]
A pair of front side members 10, 10 are disposed on both sides of the front compartment 1 in the vehicle width direction so as to be directed in the longitudinal direction of the vehicle body, and straddle between the front ends of the pair of front side members 10, 10. The bumper reinforcement 11 is coupled, and the front side member 10 and the bumper reinforcement 11 constitute a skeleton at the front of the vehicle body.
[0012]
The rear portion of the front side member 10 is bent downward with an inclined portion 10 a where it reaches the dash panel 3, and the bent ends are arranged on both lower sides of the vehicle body floor 4. A subframe 13 is disposed below the front side member 10 in a shape substantially along the front side member 10.
[0013]
The sub-frame 13 includes a pair of left and right frame main body portions 13a and 13a along the front side member 10, and a front connecting portion 13b coupled between the front portions of the pair of frame main body portions 13a and 13a. The rear connecting portion 13c coupled across the rear portions is formed in a cross-beam shape in plan view.
[0014]
And each frame main-body part 13a, 13a is couple | bonded with the front part lower surface of the front side members 10 and 10 by the coupling pin 15 via the radiator core support 14 as a 1st coupling part in each front end part, and rear end The front side members 10 and 10 are connected to the lower rear surfaces of the front side members 10 and 10 by connecting pins 15. Further, the sub-frame 13 has a middle portion between the front end portion and the rear end portion of each frame main body portion 13a, 13a on the lower surface of the front and rear middle portions of the front side members 10, 10 as a second coupling portion. The bracket 16 and the connecting pin 15 are connected.
[0015]
In this case, the radiator core support 14 is made of a light alloy material such as an aluminum material, and the coupling strength between the front end portions of the frame main body portions 13 a and 13 a and the front lower surfaces of the front side members 10 and 10 is determined by the bracket 16. The joint strength between the intermediate portion of the portions 13a and 13a and the lower surface of the intermediate portion of the front side members 10 and 10 is set lower, and the upper rear end portion thereof is disposed in the longitudinal direction of the vehicle body above the front side members 10 and 10. It is welded to the front end of the hood ledge 17.
[0016]
Incidentally, the hood ledge 17 is joined at a rear end portion thereof to a front pillar 18 disposed in the vertical direction of the vehicle body behind the dash panel 2, and the front pillar 18 is located below the extension side member 12. Further, the side sill 19 extending along this is joined.
[0017]
Thus, in this front vehicle body structure, the radiator core support 14 that connects the front end of the sub-frame 13 (the front end of the frame main body portions 13a and 13a) and the front lower surface of the front side members 10 and 10 is provided. By being made of a light alloy material whose strength is lower than the strength of the bracket 16 that joins the intermediate portion of the frame main body portions 13a, 13a of the subframe 13 and the lower surface of the intermediate portion of the front side members 10, 10, When a load is applied from the front of the vehicle body, the front end portion of the subframe 13 by the radiator core support 14 and the front lower surfaces of the front side members 10 and 10 are shown in FIG. Are broken and separated, the load is applied to the front side members 10 and 10 and the subframe 1. Can be transmitted is dispersed in the side.
[0018]
Therefore, according to this front body structure, as shown in FIG. 4 in which the same reference numerals are assigned to the corresponding parts as in FIG. 1, the axial crushing (collapse deformation) of the vehicle body due to this load is reduced to the front side members 10 and 10 side. Therefore, it can be generated on the side of the sub-frame 13 respectively, so that the connection between the front end portion of the sub-frame 13 and the front lower surface of the front side members 10 and 10 is not separated by the load as compared with the conventional front body structure. The energy absorption efficiency according to this load can be significantly improved.
[0019]
Further, according to this front body structure, after the coupling between the front end portion of the sub-frame 13 and the front lower surface of the front side members 10 and 10 by the radiator core support 14 is separated, the strength of the radiator core support 14 is exceeded. The connection between the intermediate portion of the sub-frame 13 (the intermediate portion in the frame main body portions 13a and 13a) and the lower surface of the intermediate portion of the front side members 10 and 10 by the high-strength bracket 16 remains without being separated. Since it is possible to make it difficult for the vehicle body to be deformed due to the load behind, the deformation of the dash panel 2 provided behind the vehicle can be suppressed and the space of the vehicle compartment 3 can be secured.
[0020]
Furthermore, according to this front vehicle body structure, since the radiator core support 14 is made of a light alloy material such as an aluminum material, the coupling rigidity is lower than when other materials (for example, iron members) are used. Not only can it be done, it can also be reduced in weight.
[0021]
Next, an embodiment of the present invention will be described in detail with reference to FIGS.
5 to 9 show an embodiment of a front body structure of a vehicle according to the present invention, and FIG. 5 shows a main part (first coupling portion) in the front body structure of the vehicle according to an embodiment of the present invention. 6 is a side view of the coupling bracket of FIG. 5, FIG. 7 is a sectional view showing a schematic configuration of the front vehicle body structure in which the same reference numerals are assigned to the corresponding parts to FIG. 1, and FIG. FIG. 9 is a cross-sectional view showing the behavior of the front vehicle body structure at the initial stage when a load is input from the front of the vehicle body, in which the same reference numerals are assigned to the corresponding portions in FIG. Note that description of the same parts as those in the reference example described above is omitted.
[0022]
In the case of this embodiment, the front end portion of the subframe 13 (the front end portion of the frame main body portions 13a and 13a) and the front lower surface of the front side members 10 and 10 are the first as shown in FIGS. It couple | bonds by the coupling bracket 20 as a coupling | bond part.
[0023]
Specifically, the coupling bracket 20 is made of a light alloy material such as an aluminum material, and includes a first attachment portion 21 attached to the front end portion of the frame main body portions 13a and 13a in the subframe 13 and the front side members 10 and 10 in front. A second attachment portion 22 attached to the lower surface of the portion, and a connection portion 23 for connecting the first and second attachment portions 21 and 22, and the thickness of the connection portion 23 is the first and second. The attachment portions 21 and 22 are thinner than the wall thickness. In this case, the first and second attachment portions 21 and 22 have substantially the same shape, and are connected in the front-rear reverse direction with the connection portion 23 interposed therebetween.
[0024]
The first and second attachment portions 21 and 22 include attachment surfaces 21a and 22a for the frame main body portions 13a and 13a and the front side members 10 and 10, respectively, and other surfaces 21b and 22b of the attachment surfaces 21a and 22a. As shown in FIG. 7, through holes 21c and 22c are inserted through the connecting pins 15 so that the frame main body portions 13a and 13a and the front side members 10 and 10 are penetrated. It is joined to.
[0025]
In addition, constricted portions 21e and 22e for allowing the coupling pin 15 to be inserted into the through holes 21c and 22c are provided in the inclined portions 21d and 22d at the rear of the through hole 21c (forward in the through hole 22c). A through hole 24 penetrating between the back surface portions 21f and 22f of the first and second attachment portions 21 and 22 (that is, the vehicle body longitudinal direction) is formed at the approximate center of the connection portion 23. Is formed to become smaller from the front side of the vehicle body toward the rear side.
[0026]
Thus, in the front body structure of the automobile having such a configuration, the coupling bracket 20 that couples the front end portion of the sub-frame 13 and the front lower surface of the front side members 10 and 10 includes the first and second mounting portions. While the vehicle body rigidity can be ensured by the thickness and height of 21 and 22, the connecting portion 23 is formed thinner than the thickness of the first and second mounting portions 21 and 22. When a load is applied, the connecting portion 23 is broken, and the coupling between the front end portion of the subframe 13 and the front lower surface of the front side members 10 and 10 by the coupling bracket 20 can be broken and separated. Can be efficiently distributed and transmitted to the front side members 10 and 10 side and the subframe 13 side.
[0027]
By the way, in the front compartment 1 of this vehicle body, when a load is applied from the front of the vehicle body to the lower surface of the front side members 10, 10 that are the vehicle body front of the coupling bracket 20, interference that interferes with the connection portion 23 of the coupling bracket 20. A breaking bracket 30 as a means is provided.
[0028]
Here, as shown in FIG. 8, the fracture bracket 30 includes an attachment portion 31 attached to the lower surfaces of the front side members 10 and 10, and a coupling bracket 20 extending downward from the attachment portion 31 and on the vehicle body rear side. And a main body 32 having a protruding portion 32a protruding in the direction of the connecting portion 23. The mounting portion 31 is attached to the lower surfaces of the front side members 10 and 10 using a technique such as spot welding. .
[0029]
Thereby, in this front body structure, when a load is applied from the front of the vehicle body, as shown in FIG. 9, the fracture bracket 30 is moved backward by the energy due to the load, and the protruding portion 32 a is connected to the connection portion 23 of the coupling bracket 20. Because of the interference, the connecting portion 23 can be easily broken.
[0030]
Therefore, the coupling between the front end portion of the subframe 13 and the front lower surface of the front side members 10 and 10 by the coupling bracket 20 is broken and separated, and the load is separated from the front side members 10 and 10 side and the subframe 13 side. And more efficiently dispersed and transmitted.
[0031]
At this time, a through hole 24 is formed in the coupling bracket 20 substantially at the center of the connection portion 23, and the protrusion 32 a of the fracture bracket 30 penetrates the through hole 24, whereby the fracture of the coupling bracket 20. Therefore, it is possible to reliably cause axial crushing (collapse deformation) of the vehicle body due to the load on the front side members 10 and 10 side and the sub frame 13 side. It is possible to further improve the energy absorption efficiency according to the above.
[0032]
Of course, also in this front body structure, after the coupling between the front end portion of the sub-frame 13 by the coupling bracket 20 and the front lower surface of the front side members 10 and 10 is separated, the bracket having higher strength than the coupling bracket 20 16, the intermediate portion of the sub-frame 13 (intermediate portion of the frame main body portions 13a and 13a) and the lower surface of the intermediate portion of the front side members 10 and 10 remain unseparated, so that from the intermediate portion to the rear, Since the deformation of the vehicle body due to the load can be made difficult to occur, the deformation of the dash panel 2 provided behind this can be suppressed, and the space of the vehicle compartment 3 can be secured.
[0033]
Furthermore, according to this front vehicle body structure, the coupling bracket 20 is formed using a light alloy material such as an aluminum material, so that the sub bracket can be compared with a case where other materials (for example, iron members) are used. Not only can the rigidity of the connection between the front end portion of the frame 13 and the front lower surfaces of the front side members 10 and 10 be lowered, but also the weight can be reduced.
[0034]
In addition, although the front body structure of the automobile in the present invention has been described by taking the above-mentioned reference example and one embodiment as examples, the present invention is not limited to this, and various implementations are possible without departing from the gist of the present invention. A form can be adopted. For example, in the above-described reference example , an aluminum material is used as the first coupling portion that couples the front end portion of the subframe 13 (the front end portion of the frame main body portions 13a and 13a) and the front lower surface of the front side members 10 and 10. Although the case where the radiator core support 14 made of a light alloy material such as the above is used has been described, in summary, as the first coupling portion, an intermediate portion of the subframe 13 (intermediate portion in the frame main body portions 13a and 13a) and As long as the material has a lower strength than the strength of the second coupling portion (in the present embodiment, the bracket 16) that couples the lower surface of the intermediate portion of the front side members 10 and 10, various materials and A connecting member made of a material can be widely applied.
[0035]
In the embodiment described above, if the coupling bracket 20 as a first coupling portion, and a breaking bracket 30 as interference means is formed with a shape as shown in FIGS. 5 and 8 However, the present invention is not limited to this, and in short, a first attachment portion attached to the front end portion of the subframe 13, a second attachment portion attached to the lower surface of the front portion of the front side member 10, and A first connecting portion having a connection portion connecting the first and second attachment portions, wherein the thickness of the connection portion is smaller than the thickness of the first and second attachment portions; and Various other shapes can be widely applied as long as they are interference means that are provided in front of the first coupling portion and are interfered with the connecting portion when a load is applied from the front of the vehicle.
[0036]
Further, in the reference examples and the embodiment described above, the left and right sub-frame 13 along the front side member 10 a pair of frame body portion 13a, a 13a, between front portions of the pair of frame body portion 13a, 13a The present invention has been described by taking as an example the case where the front connection part 13b joined across the rear part and the rear connection part 13c joined across the rear part are formed in a cross-beam shape in plan view. Needless to say, it is not limited to.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a schematic configuration of a front body structure of an automobile according to a reference example of the present invention.
FIG. 2 is a schematic configuration diagram showing a front vehicle body structure in FIG. 1 as viewed from above.
3 is a cross-sectional view showing the behavior at an initial stage when a load is applied from the front of the vehicle body of FIG. 1. FIG.
4 is a cross-sectional view showing the behavior at the final stage when a load is applied from the front of the vehicle body of FIG. 1. FIG.
5 is a perspective view of a main portion of the front body structure of a motor vehicle to an embodiment of the present invention.
6 is a schematic configuration diagram showing a first coupling portion in FIG. 5 as viewed from the side. FIG.
7 is a sectional view showing a schematic configuration of a front body structure of a motor vehicle to an embodiment of the present invention.
FIG. 8 is a perspective view showing a schematic configuration of the interference means in FIG. 5;
9 is a cross-sectional view showing the behavior of the initial stage when a load is applied from the front of the vehicle body of FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Front side member 13 ... Sub-frame 13a ... Frame main-body part 13b ... Front connection part 13c ... Back connection part 14 ... Radiator core support (1st connection part)
15 ... coupling pin 16 ... bracket (second coupling part)
20... Coupling bracket (first coupling part)
21 ... 1st attachment part 22 ... 2nd attachment part 23 ... Connection part 24 ... Through-hole 30 ... Breaking bracket (interference means)

Claims (4)

A front side member is disposed in the vehicle body longitudinal direction on both sides in the vehicle body width direction, and a subframe is disposed below the front side member, and the front end of the subframe is placed on the front lower surface of the front side member. In the front body structure of an automobile, the rear end portion is coupled to the rear lower surface of the front side member, and the middle portion of the front end portion and the rear end portion is coupled to the front lower portion of the front side member and the intermediate lower surface of the rear portion, respectively. ,
The first frame is coupled by a first coupling unit that couples the front end of the subframe and the front lower surface of the front side member,
The second frame is coupled by a second coupling unit that couples the middle part of the sub-frame and the lower surface of the middle part of the front side member,
Intensity of the first coupling part is rather low than the strength of the second coupling part,
The first coupling part is:
A first attachment portion attached to the front end portion of the subframe;
A second attachment portion attached to the front lower surface of the front side member;
A connecting portion for connecting the first and second mounting portions;
A front body structure of an automobile, wherein a thickness of the connecting portion is thinner than a thickness of the first and second mounting portions . The front body structure of an automobile according to claim 1, wherein the first coupling portion is made of a light alloy material. The front body structure of an automobile according to claim 1 or 2 , wherein a through-hole penetrating in the longitudinal direction of the vehicle body is formed substantially in the center of the connection portion. The front body of an automobile according to any one of claims 1 to 3, wherein an interference means for interfering with the connecting portion when a load is applied from the front of the vehicle body is provided in the front of the connecting portion. Construction.

Images