Front vehicle body structure

Abstract

To provide a front vehicle body structure making it possible to upgrade the freedom in a layout of a subframe and to appropriately control a deformation mode of the subframe.SOLUTION: A front vehicle body structure includes a pair of left and right front side frames 5 extending in a fore-and-aft direction of a vehicle body 2, a suspension cross member 8 which extends in a vehicle width direction below the pair of left and right front side frames 5 and whose left and right ends are connected to middle parts of the left and right front side frames 5, a pair of left and right subframes 9 which extend in the fore-and-aft direction of the vehicle body 2 and whose rear parts are connected to the left and right ends of the suspension cross member 8, and a pair of left and right coupling frames 26 that extend in the fore-and-aft direction of the vehicle body 2 and couple the left and right ends of the suspension cross member 8 with the rear parts of the left and right front side frames 5.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a front vehicle body structure having a subframe below a front side frame. [Background technology]

[0002] Generally, the body of an automobile or the like absorbs the impact load input to the bumper beam during a frontal collision or the like by deformation (buckling) of the front side frames, subframe, etc. For such a vehicle body, various front body structures have been proposed to appropriately control the deformation mode of the subframe when subjected to an impact load.

[0003] For example, Patent Document 1 discloses a technology in which a subframe extending from the front end of the engine compartment to the underside of the floor is supported on a front side frame at at least three attachment points. Here, Patent Document 1 discloses subframe support portions formed on a suspension cross member as attachment points for supporting the subframe on the front side frame. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-310755 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the subframe disclosed in the aforementioned Patent Document 1 is long and extends from the front end of the engine compartment to the underside of the floor. Such long side frames are likely to be subject to layout restrictions when assembled to the vehicle body. Furthermore, a long subframe may make it difficult to appropriately control the deformation mode.

[0006] An object of the present invention is to provide a front vehicle body structure that improves the degree of freedom in the layout of a subframe and can appropriately control the deformation mode of the subframe. [Means for solving the problem]

[0007] A front body structure according to one embodiment of the present invention comprises a pair of left and right front side frames extending in the fore-and-aft direction of the vehicle body, a suspension cross member extending in the vehicle width direction below the pair of left and right front side frames and having its left and right ends connected to the midpoints of the pair of left and right front side frames, a pair of left and right subframes extending from the front of the vehicle body in the fore-and-aft direction of the vehicle body and having their rear ends connected to the left and right ends of the suspension cross member, and a pair of left and right connecting frames extending in the fore-and-aft direction of the vehicle body and connecting the left and right ends of the suspension cross member to the rears of the pair of left and right front side frames. [Effects of the Invention]

[0008] According to the front vehicle body structure of the present invention, the degree of freedom in the layout of the subframe is improved, and the deformation mode of the subframe can be appropriately controlled. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a perspective view schematically illustrating a front body frame of a vehicle; [Figure 2] A side view showing the front body frame of a vehicle [Figure 3] Side view of the front bodywork of a vehicle with the front suspension arms removed [Figure 4] Exploded side view showing the front bodywork of the vehicle with the front suspension arms removed [Figure 5] FIG. 1 is a perspective view showing the vehicle body framework around the subframe, seen from diagonally below the vehicle body. [Figure 6] FIG. 1 is a perspective view showing a subframe and a support cross member. [Figure 7] Side view showing the subframe [Figure 8] Schematic diagram showing the front body frame deformed by an impact load from the front of the vehicle DETAILED DESCRIPTION OF THE INVENTION

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the accompanying drawings, in which: Figure 1 is a perspective view showing a front body frame of a vehicle according to an embodiment of the present invention;

[0011] As shown in FIGS. 1 to 4, a vehicle body 2 that constitutes the front part of a vehicle 1 is constructed by assembling panel-shaped members that are formed by press-forming steel plates, for example.

[0012] The vehicle body 2 has a pair of left and right front side frames 5, a radiator support 6, a pair of left and right upper side frames 7, a suspension cross member 8, and a pair of left and right sub-frames 9.

[0013] Each front side frame 5 extends in the longitudinal direction of the vehicle body 2. The base end of each front side frame 5 expands downward while curving outward in the vehicle width direction, so that the base end of each front side frame 5 is connected to left and right front pillars 11 and left and right side sills 12, respectively (see Figures 2 to 4).

[0014] The radiator support 6 has a pair of left and right radiator support sides 15 , an upper radiator support 16 , and a lower radiator support 17 .

[0015] The upper end of each radiator support side 15 is joined to the left and right end of the upper radiator support 16, respectively. The lower end of each radiator support side 15 is joined to the left and right end of the lower radiator support 17, respectively. This gives the radiator support 6 a substantially rectangular frame shape.

[0016] Further, the radiator support sides 15 are each provided with a plate-shaped frame mounting portion 18 that protrudes outward in the vehicle width direction.

[0017] The front end portion of each front side frame 5 is connected to the rear surface of each frame mounting portion 18 by welding or the like.

[0018] Additionally, the base ends of crash boxes 20 are connected to the front of each frame mounting portion 18 by fastening or the like. A bumper beam 21 extending in the vehicle width direction is connected to the front ends of these crash boxes 20. Each crash box 20 is capable of buckling to absorb impact loads input to the bumper beam 21. Furthermore, each crash box 20 is capable of transmitting impact loads that are not absorbed by buckling to each front side frame 5.

[0019] Each upper side frame 7 extends in the front-to-rear direction of the vehicle body 2, above and outboard of each front side frame 5 in the vehicle width direction. A base end of each upper side frame 7 is connected to the left and right front pillars 11, respectively. Furthermore, a front end of each upper side frame 7 is connected to the left and right ends of the upper radiator support 16, respectively, by welding, for example.

[0020] The suspension cross member 8 extends in the vehicle width direction below each front side frame 5. The left and right ends of the suspension cross member 8 have an upwardly protruding shape. The left and right ends of the suspension cross member 8 are connected to the bottom of each front side frame 5 midway through by fastening using bolts 23, for example.

[0021] The suspension cross member 8 connected to each front side frame 5 in this manner stiffens a mid-region of each front side frame 5. As a result, the region to which the suspension cross member 8 is connected in the longitudinal direction of each front side frame 5 is set to have higher rigidity against impact loads than other regions. In other words, the rigidity of the regions in front of and behind the connection region with the suspension cross member 8 in each front side frame 5 is set relatively lower than the rigidity of the connection region with the suspension cross member 8. As a result, the regions in front of and behind the connection region with the suspension cross member 8 in each front side frame 5 are set as buckling areas Ab1 and Ab2, respectively, against impact loads.

[0022] Additionally, first arm support members 25 are provided near the rear of the left and right ends of the suspension cross member 8. Each first arm support member 25 extends downward from the left and right ends of the suspension cross member 8. A first bearing 25a for supporting the front of each suspension arm 22 is provided at the extending end of each first arm support member 25.

[0023] Furthermore, a connecting member 27 is connected to the extending end of each first arm support member 25. Each connecting member 27 is made of, for example, a sheet metal member that extends rearward from the extending end of each first arm support member 25. Furthermore, a second arm support member 28 is formed on the extending end of each connecting member 27.

[0024] Each second arm support member 28 is fastened to the rear of each front side frame 5 using, for example, bolts 29. Each second arm support member 28 is also provided with a second bearing 28a for supporting the rear of each suspension arm 22. In this embodiment, each second bearing 28a supports the rear of each suspension arm 22 between itself and each front side frame 5.

[0025] A support cross member 35 is attached to the bottom of each connecting member 27 configured in this manner (see Figure 5). Each support cross member 35 is made of, for example, a sheet metal member extending in the fore-and-aft direction of the vehicle body 2 along the bottom surface of each connecting member 27. In this embodiment, each support cross member 35, together with each connecting member 27, constitutes each connecting frame 26. For this reason, multiple locations of each support cross member 35 are fastened to each connecting member 27 using, for example, bolts 36.

[0026] Here, the tip of each support cross member 35 extends to a position facing the bottom of each first arm support member 25. The tip of each support cross member 35 is fastened to the bottom of each first arm support member 25 using, for example, bolts 37.

[0027] Each connecting frame 26 configured in this manner connects the left and right ends of the suspension cross member 8 to the rear of each front side frame 5. Each connecting frame 26 is provided in a longitudinal position that substantially coincides with the buckling area Ab2 of each front side frame 5. The rigidity of each connecting frame 26 is set relatively lower than the rigidity of the suspension cross member 8. Therefore, when an impact load is input from the front of the vehicle body 2, each connecting frame 26 buckles more easily than the suspension cross member 8.

[0028] 5, each support cross member 35 has a branch portion 35a that branches in a Y shape toward the inside in the vehicle width direction. The end of each branch portion 35a is fastened to the middle portion of the suspension cross member 8 using, for example, a bolt 38.

[0029] As shown in FIGS. 2 to 4, each sub-frame 9 extends in the longitudinal direction of the vehicle body 2 in a region from the front of the vehicle body 2 to the vicinity of the rear edge of the suspension cross member 8, for example.

[0030] A sub-bumper beam 40 extending in the vehicle width direction is connected, for example, by welding, to the front end of each sub-frame 9. Behind the sub-bumper beam 40, the front portion of each sub-frame 9 is fastened to the radiator support lower 17 using, for example, bolts 41.

[0031] Additionally, the rear portions of each sub-frame 9 are connected to the left and right ends of the suspension cross member 8. In this embodiment, each sub-frame 9 has a first connection portion 45 and a second connection portion 46 as connection portions to the suspension cross member 8, respectively.

[0032] Each first connection portion 45 connects each sub-frame 9 to the front portion of the left and right ends of the suspension cross member 8. In other words, the first connection portion 45 connects the sub-frame 9 to the suspension cross member 8 forward of the first arm support member 25. For this reason, the first connection portion 45 has a bracket 47 that is interposed in the gap between the sub-frame 9 and the suspension cross member 8.

[0033] The bracket 47 has, for example, a bolt insertion tube 47a. This bolt insertion tube 47a has, for example, a cylindrical pipe shape. The bolt insertion tube 47a passes through the subframe 9 in the vertical direction and is fixed to the subframe 9 by welding or the like. Furthermore, the bolt insertion tube 47a protrudes upward to a position where it abuts against the bottom surface of the suspension cross member 8.

[0034] On the upper surface side of the subframe 9, a leg portion 47b is connected midway through the bolt insertion tube 47a. The leg portion 47b is formed, for example, from a sheet metal member having a generally hat shape in side view. The leg portion 47b stiffens the bolt insertion tube 47a. For this purpose, the top of the leg portion 47b is connected to the bolt insertion tube 47a by welding or the like. Furthermore, the front and rear end portions of the leg portion 47b are connected to the upper surface of the subframe 9 by welding or the like.

[0035] A bolt 48 is inserted into each bolt insertion tube 47a of each bracket 47 configured in this manner. Each bolt 48 inserted into each bolt insertion tube 47a is fastened to the suspension cross member 8. In this way, each bracket 47 connects each subframe 9 to the suspension cross member 8.

[0036] Each second connection portion 46 connects each subframe 9 to the rear portion of the left and right ends of the suspension cross member 8. That is, the second connection portion 46 connects the subframe 9 to the suspension cross member 8 at a position corresponding to the first arm support member 25. For this reason, the second connection portion 46 is provided with a bolt insertion hole at a position corresponding to the fastening portion between the first arm support member 25 and the support cross member 35. Then, at the second connection portion 46, the subframe 9 is connected to the first arm support member 25 (suspension cross member 8) by co-fastening (co-tightening) with the support cross member 35 using bolts 37.

[0037] The rigidity of each sub-frame 9 is set relatively lower than the rigidity of the suspension cross member 8. Therefore, when an impact load is input from the front of the vehicle body 2, the area of each sub-frame 9 forward of the first connection portion 45 buckles more easily than the suspension cross member 8. In other words, the area of each sub-frame 9 that roughly coincides with the buckling area Ab1 of each front side frame 5 is set as an area that buckles more easily than the suspension cross member 8.

[0038] In this case, in order to appropriately control the buckling mode of each sub-frame 9, it is preferable to provide beads 50 at key points on each sub-frame 9.

[0039] In the vehicle body 2 configured as above, when an impact load due to a frontal collision or the like is input to the bumper beam 21, the sub-bumper beam 40, etc., each front side frame 5 buckles mainly in the buckling areas Ab1, Ab2, as shown in FIG.

[0040] Further, each sub-frame 9 buckles in a region corresponding to buckling area Ab1 below each front side frame 5. Furthermore, each connecting frame 26 buckles in a region corresponding to buckling area Ab2 below each front side frame 5.

[0041] In this way, each sub-frame 9 and each connecting frame 26 buckles in the areas (buckling areas Ab1, Ab2) that are consistent with each front side frame 5 in the longitudinal direction of the vehicle body 2.

[0042] As such, the front body structure of this embodiment comprises a pair of left and right front side frames 5 extending in the fore-and-aft direction of the vehicle body 2, a suspension cross member 8 extending in the vehicle width direction below the pair of left and right front side frames 5 and having its left and right ends connected to the middle portions of the pair of left and right front side frames 5, a pair of left and right subframes 9 extending in the fore-and-aft direction of the vehicle body 2 and having rear portions connected to the left and right ends of the suspension cross member 8, and a pair of left and right connecting frames 26 extending in the fore-and-aft direction of the vehicle body 2 and connecting the left and right ends of the suspension cross member 8 to the rear portions of the pair of left and right front side frames 5.

[0043] This improves the degree of freedom in the layout of each sub-frame 9, and also makes it possible to appropriately control the deformation mode of the sub-frame 9.

[0044] That is, the length of each subframe 9 is set to a length extending in the fore-and-aft direction of the vehicle body 2 in the region from the front of the vehicle body 2 to near the rear edge of the suspension cross member 8. This allows for significantly improved layout freedom when assembling each subframe 9 to the vehicle body 2, compared to when each subframe 9 extends to a position where it is connected to the rear of each front side frame 5. Furthermore, by setting the length of each subframe 9 short in this manner, it is possible to appropriately control the deformation mode in response to an impact load.

[0045] Furthermore, even when the length of each sub-frame 9 is set short in this manner, the left and right ends of the suspension cross member 8 are connected to the rear of each front side frame 5 using a pair of left and right connecting frames 26. This allows the impact load input to the sub-bumper beam 40 to be appropriately absorbed also behind the suspension cross member 8.

[0046] In this case, the rear of each subframe 9 is fixed to the suspension cross member 8 by fastening via brackets 47. This allows each subframe 9 to be firmly fixed to the suspension cross member 8 even when there is a gap between the rear of each subframe 9 and the suspension cross member 8.

[0047] Additionally, the rear of each subframe 9 is connected to the suspension cross member 8 by fastening it together with the support cross member 35, which is a component of each connecting frame 26. This allows the deformation mode of each subframe 9 to be appropriately controlled by shortening the length of each subframe 9, while also enabling accurate load transmission from each subframe 9 to each connecting frame 26.

[0048] Furthermore, each sub-frame 9 has a bead 50 midway in the fore-and-aft direction of the vehicle body 2. By providing such a bead 50 on each sub-frame 9, a buckling start point can be set on each sub-frame 9, making it possible to more appropriately control the deformation mode of each sub-frame 9.

[0049] The invention described in the above embodiments is not limited to these embodiments, and various modifications can be made in the implementation stage without departing from the gist of the invention. Furthermore, the above embodiments include inventions at various stages, and various inventions can be extracted by appropriate combinations of the disclosed multiple constituent elements.

[0050] For example, if the stated problem can be solved and the stated effect can be obtained even if some of the constituent elements are deleted from all the constituent elements shown in the above form, the configuration from which these constituent elements are deleted can be extracted as an invention. [Explanation of symbols]

[0051] 1 … Vehicle 2... Body 5...Front side frame 6... Radiator support 7 ... Upper side frame 8... Suspension cross member 9... Subframe 11... Front pillar 12...Side sill 15... Radiator support side 16... Radiator support upper 17... Radiator support lower 18... Frame mounting part 20... Crash Box 21... Bumper beam 22...Suspension arm 23... Bolt 25 ... First arm support member 25a ... First bearing 26 ... Connecting frame 27 ... Connecting member 28 ... second arm support member 28a ... Second bearing 29... Bolt 35 ... Support cross member 35a ... Branch 36...volts 37...volts 38...volts 40... Sub-bumper beam 41... Bolt 45 … First connection 46 … Second connection 47... Bracket 47a ... Bolt insertion pipe 47b … Legs 48...volts 50... Bead Ab1,Ab2 ... Buckling area

Claims

1. a pair of left and right front side frames extending in the front-rear direction of the vehicle body; a suspension cross member extending in a vehicle width direction below the pair of left and right front side frames, with left and right ends connected to mid-portions of the pair of left and right front side frames; a pair of left and right subframes extending from a front portion of the vehicle body in a longitudinal direction of the vehicle body and having rear portions connected to left and right ends of the suspension cross member; a pair of left and right connecting frames extending in the front-rear direction of the vehicle body and connecting left and right ends of the suspension cross member to rear portions of the pair of left and right front side frames; A front body structure comprising:

2. the pair of left and right subframes each include a first connection portion connected to a front portion of a left and right end portion of the suspension cross member, 2. The front vehicle body structure according to claim 1, wherein the first connection portion is fixed to the suspension cross member by fastening via a bracket.

3. the pair of left and right subframes each include a second connection portion connected to a rear portion of the left and right end portions of the suspension cross member, 2. The front vehicle body structure according to claim 1, wherein the second connection portion is connected to the suspension cross member by fastening together with a component of the connecting frame.

4. 2. The front vehicle body structure according to claim 1, wherein the pair of left and right sub-frames have beads midway in the front-rear direction of the vehicle body.

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