JP4158445B2 - Rear subframe structure of vehicle - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a rear subframe skeleton structure of a vehicle, and more particularly to a rear subframe skeleton structure of a vehicle in which two suspension arms are arranged along the vehicle width direction adjacent to each other in the vehicle body longitudinal direction.
[0002]
[Prior art]
Conventionally, the following structure is known as an example of a rear subframe skeleton structure of a vehicle in which two suspension arms are arranged along the vehicle width direction adjacent to each other in the longitudinal direction of the vehicle body.
[0003]
As shown in FIG. 11, in the rear subframe skeleton structure of this vehicle, the skeleton of the rear subframe 100 includes a cross member 102 extending in the vehicle width direction, and the vicinity of both end portions 102A and 102B of the cross member 102. It is comprised by the two side rails 104 and 106 extended toward the vehicle width direction outer side diagonally forward. Further, both end portions 102A and 102B of the cross member 102 are fixed to the left and right rear side members 108 on the vehicle body side via mounts, and the front end portions 104A and 106A of the side rails 104 and 106 are connected to the cross member on the vehicle body side. 110 is fixed through a mount.
[0004]
As a related prior art, there is JP-A 2000-255448.
[0005]
[Problems to be solved by the invention]
However, in such a rear subframe skeleton structure of a vehicle, an input point (support point) P1 of a lower arm as a suspension arm in the rear subframe 100 is at a connecting portion between the cross member 102 and the side rails 104 and 106. An input point (support point) P2 of a tie rod as a suspension arm in the rear subframe 100 is set on the cross member 102 on the vehicle rear side of the support point P1 of the lower arm. Yes.
[0006]
As a result, the input load F2 acting on the input point P2 of the tie rod can be received by the axial force of the cross member 102, but acts on the input point P1 of the lower arm that is larger in input ratio than the input point P2 of the tie rod. The bending moment M1 is generated by the input load F1. The bending moment M1 acts in the direction in which the end portion 102A of the cross member 102 is bent, and also in the direction in which the bracket 112 and the side rail 104 are bent. For this reason, as shown by the two-dot chain line in FIGS. 11, 12, and 13, the deformation of the rear subframe 100 becomes large.
[0007]
In view of the above facts, an object of the present invention is to obtain a rear subframe skeleton structure for a vehicle that is small in deformation with respect to an input load from a suspension arm.
[0008]
[Means for Solving the Problems]
The present invention according to claim 1 is a rear subframe skeleton structure for a vehicle in which two suspension arms are arranged along the vehicle width direction so as to be adjacent to each other in the vehicle longitudinal direction.
A cross member disposed on one input point of the two suspension arms, having an end fixed to the body, and receiving an input load from the input point by an axial force ;
The cross member is disposed on the opposite side of the cross member in the vehicle longitudinal direction with respect to the other input point of the two suspension arms, and extends obliquely outward in the vehicle width direction from one end fixed to the cross member. A pair of left and right side rails, the other end of which is fixed to the body and receives a bending moment generated by an input load from the other input point by an axial force ;
It is characterized by having.
[0009]
Therefore, the input load inputted to one of the two suspension arms arranged along the vehicle width direction adjacent to the longitudinal direction of the vehicle body is arranged on the input point, and the end portion is fixed to the body. It can be received by the axial force of the cross member. Also, the bending moment generated by the input load input to the other of the two suspension arms is arranged on the opposite side of the cross member in the vehicle longitudinal direction with respect to this input point, and is fixed to the cross member at one end. It can be received by the axial force of a pair of left and right side rails that extend obliquely outward in the vehicle width direction and the other end is fixed to the body. As a result, the deformation of the rear subframe can be reduced with respect to the input load from the suspension arm.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of a vehicle rear subframe skeleton structure according to the present invention will be described with reference to FIGS.
[0011]
In the figure, the arrow FR indicates the vehicle front direction, the arrow UP indicates the vehicle upward direction, and the arrow IN indicates the vehicle width inside direction.
[0012]
As shown in FIG. 1, the rear suspension 10 of the present embodiment is a double wishbone suspension, and includes an L-shaped lower arm 12 and a V-shaped upper arm 14. A toe control link with a tie rod 16 is also provided. The lower arm 12, the upper arm 14 and the tie rod 16 have one end portions 12A, 14A and 16A connected to the rear subframe 18, respectively.
[0013]
As shown in FIG. 2, the skeleton of the rear sub-frame 18 includes a cross member 20 extending in the vehicle width direction and left and right side rails 22 and 24. 24 extends from one end 22A, 24A fixed in the vicinity of both ends 20A, 20B of the cross member 20 to the front side obliquely outward in the vehicle width direction. The cross member 20 and the left and right side rails 22 and 24 each have a closed cross-sectional structure.
[0014]
A bracket 26 that supports the end portion 14A of the upper arm 14 so as to be swingable is disposed above the root portions (vehicle body rear side end portions) 22A, 24A of the side rails 22, 24. A pair of left and right arm brackets 28 that swingably support the end 12A of the lower arm 12 are disposed on the lower surface side of the cross member 20, and the arm bracket 28 includes the cross member 20 and the side rails 22, 24. Are welded only to the cross member 20.
[0015]
As shown in FIGS. 3 and 4, a bracket 30 that supports the end portion 16 </ b> A of the tie rod 16 in a swingable manner is disposed on the rear side of the arm bracket 28.
[0016]
As shown in FIG. 4, the cross member 20 is disposed on the end portion 12 </ b> A serving as the input point P <b> 1 of the lower arm 12, and the side rail 24 is opposite to the input point P <b> 2 of the tie rod 16. In this embodiment, it is disposed on the vehicle front side.
[0017]
Note that the side rails 22 of the rear sub-frame 18 in the rear suspension 10 are also arranged on the opposite side of the cross member 20 in the vehicle front-rear direction with respect to the input point P2 of the tie rod 16, similarly to the side rails 24.
[0018]
As shown in FIG. 5, both end portions 20 </ b> A and 20 </ b> B of the cross member 20 are fixed to the lower surfaces of the left and right rear side members 40 as bodies via bushes (not shown). On the other hand, the front end portions 22B and 24B of the side rails 22 and 24 extending from the rear end portions 22A and 24A toward the front side obliquely outward in the vehicle width direction are not shown on the lower surface of the rear cross member 42 as a body. It is fixed through a bush.
[0019]
Next, the operation of this embodiment will be described.
[0020]
In the present embodiment, as shown in FIG. 4, the cross member 20 of the rear subframe 18 in the rear suspension 10 is disposed on the end 12 </ b> A serving as the input point P <b> 1 of the lower arm 12, and as shown in FIG. 5. Both end portions 20A and 20B of the cross member 20 are fixed to the lower surfaces of the left and right rear side members 40 as bodies through bushes (not shown).
[0021]
As a result, as shown in FIG. 6, the input load F <b> 1 to the input point P <b> 1 of the lower arm 12 can be received by the axial force of the cross member 20.
[0022]
Further, in the present embodiment, as shown in FIG. 4, the side rail 24 of the rear subframe 18 in the rear suspension 10 is opposite to the input point P2 of the tie rod 16 on the opposite side of the cross member 20 in the vehicle longitudinal direction. Then, it is arranged on the front side. Note that the side rails 22 of the rear sub-frame 18 in the rear suspension 10 are also arranged on the opposite side of the cross member 20 in the vehicle front-rear direction with respect to the input point P2 of the tie rod 16, similarly to the side rails 24. That is, the side rails 22 and 24 and the input point P2 of the tie rod 16 are disposed on the front and rear sides with the cross member 20 interposed therebetween, and the side rails 22 and 24 extend obliquely outward in the vehicle width direction.
[0023]
As a result, as shown in FIG. 6, a bending moment M is generated by the input load F2 to the input point P2 of the tie rod 16, and this bending moment M generates an input load F3 along the axial direction of the side rail 24. . For this reason, the input load F <b> 3 generated by the bending moment M can be received by the axial force of the side rail 24. The side rail 22 has the same operation and effect.
[0024]
Therefore, the displacement of the input point P1 of the lower arm 12 in the present embodiment is smaller than the displacement in the same portion of the related art shown by the one-dot chain line in FIG. Further, the displacement of the input point P2 of the tie rod 16 in the present embodiment is smaller than the displacement in the same portion of the prior art indicated by the alternate long and short dash line in FIG. Furthermore, the displacement of the input point P3 (see FIGS. 3 and 4) of the upper arm 14 in the present embodiment is also smaller than the displacement at the same portion of the related art indicated by the one-dot chain line in FIG. That is, in this embodiment, the rigidity of each input point of the lower arm 12, the tie rod 16, and the upper arm 14 is greatly improved.
[0025]
Therefore, as shown by a two-dot chain line in FIGS. 5, 6, and 7, in this embodiment, the deformation of the rear subframe 18 in the rear suspension 10 with respect to the input load from the lower arm 12 and the tie rod 16 is changed as shown in FIG. 12 and 13 can be made smaller than the deformation of the conventional structure shown by the two-dot chain line.
[0026]
In the present embodiment, the side rails 22 and 24 of the rear subframe 18 in the rear suspension 10 are disposed on the opposite side of the cross member 20 in the vehicle front-rear direction with respect to the input point P2 of the tie rod 16. For this reason, it becomes possible to arrange | position the position of the cross member 20 in the vehicle forward side compared with the conventional structure shown in FIG.11, FIG12 and FIG.13, and the side rails 22 and 24 can be shortened. Further, the arm bracket 28 of the present embodiment is downsized compared to the conventional structure shown in FIGS. As a result, the weight and cost of the rear subframe 18 can be reduced. Further, since the arm bracket 28 is welded only to the cross member 20, the number of assembling steps is small, and the cost can be reduced also in this respect.
[0027]
Further, in the prior art, an arm bracket that also serves as a gusset is disposed across the two parts in order to improve the coupling rigidity between the side rail and the cross member. Since the deformation between the members 22 and 24 and the cross member 20 is suppressed, a structure as a gusset becomes unnecessary, and the arm bracket 28 can be downsized.
[0028]
Although the present invention has been described in detail with reference to specific embodiments, the present invention is not limited to such embodiments, and various other embodiments are possible within the scope of the present invention. It will be apparent to those skilled in the art. For example, in the above-described embodiment, the front end portions 22B of the side rails 22 and 24 that extend obliquely outward in the vehicle width direction from the rear end portions 22A and 24A of the side rails 22 and 24 fixed to the cross member 20. 24B are fixed to the body, but instead, the side rails 22 and 24 fixed to the cross member 20 are extended from the front ends of the side rails 22 and obliquely outward and rearward in the vehicle width direction. It is good also as a structure which fixed the rear-end part of 24 to the body.
[0029]
【The invention's effect】
The present invention according to claim 1 is a vehicle rear subframe skeleton structure in which two suspension arms are arranged along the vehicle width direction so as to be adjacent to each other in the longitudinal direction of the vehicle body. The cross member is placed on the input point of the cross section, the end is fixed to the body, and receives the input load from the input point by the axial force, and the cross member of the two suspension arms is the front and rear of the cross member It is arranged on the opposite side of the direction, extends from one end fixed to the cross member diagonally outward in the vehicle width direction, the other end is fixed to the body, and is generated by the input load from the other input point that the bending moment for having a pair of left and right side rails for receiving the axial force, and can reduce the deformation of the rear sub-frame for the input load from the suspension arms It has the effect.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a rear suspension to which a rear subframe skeleton structure for a vehicle according to an embodiment of the present invention is applied, as seen from the obliquely forward outer side of the vehicle.
FIG. 2 is a perspective view showing the rear sub-frame skeleton structure of the vehicle according to the embodiment of the present invention as seen from the obliquely forward outer side of the vehicle.
FIG. 3 is a cross-sectional view of a part of a rear suspension to which a vehicle rear subframe skeleton structure according to an embodiment of the present invention is applied, as viewed from the front of the vehicle.
FIG. 4 is a plan view of a part of a rear suspension to which a rear subframe skeleton structure for a vehicle according to an embodiment of the present invention is applied, as viewed from above the vehicle.
FIG. 5 is a schematic plan view showing the rear subframe skeleton structure of the vehicle according to the embodiment of the present invention as viewed from above the vehicle.
FIG. 6 is a schematic plan view showing the rear subframe skeleton structure of the vehicle according to the embodiment of the present invention as viewed from the lower side of the vehicle.
FIG. 7 is a schematic front view showing the rear subframe skeleton structure of the vehicle according to the embodiment of the present invention as seen from the front of the vehicle.
FIG. 8 is a graph showing the displacement at the input point of the lower arm during a lane change.
FIG. 9 is a graph showing displacement at an input point of a tie rod at the time of a lane change.
FIG. 10 is a graph showing the displacement at the input point of the upper arm during a lane change.
FIG. 11 is a schematic plan view showing a rear subframe skeleton structure of a vehicle according to the prior art as viewed from the lower side of the vehicle.
FIG. 12 is a schematic plan view showing a rear subframe skeleton structure of a vehicle according to the prior art as viewed from above the vehicle.
FIG. 13 is a schematic front view showing a rear subframe skeleton structure of a vehicle according to the prior art as seen from the front of the vehicle.
[Explanation of symbols]
10 Rear suspension 12 Lower arm (suspension arm)
14 Upper arm 16 Tie rod (suspension arm)
18 Rear subframe 20 Rear subframe cross member 22 Rear subframe side rail 24 Rear subframe side rail 28 Arm bracket 40 Rear side member 42 Rear cross member

Claims (1)

A vehicle rear subframe skeleton structure in which two suspension arms are arranged along the vehicle width direction adjacent to each other in the vehicle longitudinal direction;
A cross member disposed on one input point of the two suspension arms, having an end fixed to the body, and receiving an input load from the input point by an axial force ;
The cross member is disposed on the opposite side of the cross member in the vehicle longitudinal direction with respect to the other input point of the two suspension arms, and extends obliquely outward in the vehicle width direction from one end fixed to the cross member. A pair of left and right side rails, the other end of which is fixed to the body and receives a bending moment generated by an input load from the other input point by an axial force ;
A rear subframe skeleton structure for a vehicle, comprising:

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