JP2004130827A - Front sub frame mounting structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To sufficiently absorb collision energy at the time of full barrier at the time of collision, and to decrease the deforming amount of a cabin at the time of offset front collision. <P>SOLUTION: On a lower wall portion in a mounting portion 20 of a front side member 12, a long hole 30 is formed continuing to a mounting hole 24, and the ling hole 30 is extended from the mounting hole 24 toward a slanting rear outside of a vehicle. Therefore, when a load over a specified value acts on a bolt 22 toward a vehicular rear side, the bolt 22 is moved along the long hole 30, and when a load over the specified value acts on the bolt 22 toward a vehicular rear inside, the bolt 22 is not moved along the long hole 30 and held in and near the mounting hole 24. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a front subframe mounting structure, and more particularly to a front subframe mounting structure for mounting a front subframe to a front side member of a vehicle such as an automobile.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, in a front subframe mounting structure of a vehicle such as an automobile, a subside frame constituting a front subframe is constituted by a subside frame main body and a projecting frame, and a projecting end of the projecting frame is rotated by a single rotation. A fastening member having a center, which is fastened to a body or a front side member of a vehicle, and the fastening member is displaced outward in a vehicle width direction from a rear end portion of a sub side frame main body, so that when a vehicle collides forward. In addition, a configuration is known in which the front sub-frame is sufficiently plastically deformed so that the collision energy given to the vehicle body based on the impact force is more sufficiently absorbed (for example, see Patent Document 1). .
[0003]
[Patent Document 1]
JP-A-10-45022 (paragraphs [0053] and [0054], FIG. 5)
[0004]
[Problems to be solved by the invention]
However, in such a front subframe mounting structure, the vehicle body is sufficiently plastically deformed at the time of a so-called full barrier frontal collision when the entire front part of the vehicle collides with a wall, etc. During a so-called offset front collision, the left and right surfaces of the front sub-frame move rearward more than the full barrier front collision. As a result, at the time of an offset front collision, there is a problem that the amount of interference between the engine and the dash panel increases and the amount of deformation of the cabin increases.
[0005]
The present invention has been made in view of the above-described circumstances, and has as its object to provide a front subframe mounting structure capable of sufficiently absorbing collision energy during a full barrier frontal collision and reducing the amount of deformation of the cabin during an offset frontal collision.
[0006]
[Means for Solving the Problems]
According to the first aspect of the present invention, there is provided a front sub-member arranged along a vehicle width direction on a pair of front side members arranged substantially parallel to a vehicle front-rear direction at both ends in a vehicle width direction. A front subframe mounting structure for fixing the frame with a fastening member,
A mounting portion formed at a rear portion of the pair of front side members and formed with a mounting hole through which the fastening member is inserted;
When a load of a predetermined value or more is applied to the fastening member toward the rear of the vehicle, the fastening member is moved from the mounting hole toward the rear of the vehicle, and the fastening member is moved to the rear of the vehicle. When a load equal to or more than a predetermined value is applied inward, a sub-frame movement control unit that holds the fastening member in the vicinity of the attachment hole and the attachment hole,
It is characterized by having.
[0007]
Therefore, when the vehicle has a full barrier frontal collision, a load equal to or greater than a predetermined value acts on the left and right fastening members from the front of the vehicle toward the rear of the vehicle. As a result, the fastening member is moved from the mounting hole to the vehicle rear side by the sub-frame movement control means of the mounting portion formed at the rear of the pair of left and right front side members. For this reason, the front sub-frame largely moves toward the vehicle rear side with respect to the front side member, so that the collision energy can be sufficiently absorbed at the time of the full barrier frontal collision.
[0008]
On the other hand, when the vehicle collides with the offset front, a load greater than or equal to a predetermined value acts on the colliding one of the left and right coupling members toward the rear inside of the vehicle. As a result, the fastening member is held in the mounting hole and in the vicinity thereof by the sub-frame movement control means formed in the rear mounting portion of the front side member. Therefore, the amount of movement of the front sub-frame toward the rear of the vehicle is reduced, so that the amount of interference between the engine and the dash panel is reduced, and the amount of deformation of the cabin can be reduced.
[0009]
According to a second aspect of the present invention, in the front sub-frame mounting structure according to the first aspect, the sub-frame movement control means is a long hole extending obliquely rearward and outward from the mounting hole. I do.
[0010]
Therefore, when the vehicle has a full barrier frontal collision, a load equal to or more than a predetermined value acts on the left and right fastening members toward the rear of the vehicle. As a result, the fastening member is formed at the rear attachment portion of the pair of left and right front side members, moves along the elongated hole extending obliquely rearward and outward from the attachment hole, and the fastening member moves from the attachment hole to the vehicle rear side. Move to For this reason, the front sub-frame largely moves toward the vehicle rear side with respect to the front side member, so that the collision energy can be sufficiently absorbed at the time of the full barrier frontal collision.
[0011]
On the other hand, when the vehicle collides with the offset front, a load greater than or equal to a predetermined value acts on the colliding one of the left and right coupling members toward the rear inside of the vehicle. As a result, the fastening member is formed at the rear mounting portion of the pair of left and right front side members, does not move along the elongated hole extending diagonally rearward and outward from the mounting hole, and the fastening member is formed of the mounting hole and the hole. It is kept nearby. Therefore, the amount of movement of the front sub-frame toward the rear of the vehicle is reduced, so that the amount of interference between the engine and the dash panel is reduced, and the amount of deformation of the cabin can be reduced.
[0012]
According to a third aspect of the present invention, in the front sub-frame mounting structure according to the first aspect, the sub-frame movement control means is formed at a position separated from the mounting hole by a predetermined distance in a direction obliquely rearward and outward of the vehicle. It is a through hole.
[0013]
Therefore, when the vehicle has a full barrier frontal collision, a load equal to or more than a predetermined value acts on the left and right fastening members toward the rear of the vehicle. As a result, the fastening member moves toward the vehicle rear side from the mounting hole formed in the rear mounting portion of the pair of left and right front side members, and finally is separated by a predetermined distance toward the diagonally rearward outside of the vehicle. Move to the through hole formed at the position. For this reason, the front sub-frame largely moves toward the vehicle rear side with respect to the front side member, so that the collision energy can be sufficiently absorbed at the time of the full barrier frontal collision.
[0014]
On the other hand, when the vehicle collides with the offset front, a load greater than or equal to a predetermined value acts on the colliding one of the left and right coupling members toward the rear inside of the vehicle. As a result, the fastening member is formed at the rear mounting portion of the pair of left and right front side members, does not reach the through hole formed at a predetermined distance away from the mounting hole toward the vehicle diagonally rearward outside, and the fastening member is It is held in the mounting hole and its vicinity. Therefore, the amount of movement of the front sub-frame toward the rear of the vehicle is reduced, so that the amount of interference between the engine and the dash panel is reduced, and the amount of deformation of the cabin can be reduced.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
A first embodiment of a front subframe mounting structure according to the present invention will be described with reference to FIGS.
[0016]
In the drawings, an arrow FR indicates a forward direction of the vehicle body, an arrow IN indicates an inward direction of the vehicle body, and an arrow UP indicates an upward direction of the vehicle body.
[0017]
As shown in FIG. 1, a pair of left and right front side members 12 are disposed along the vehicle front-rear direction at both ends in the vehicle width direction at the front of the vehicle body 10. Has a front sub-frame 14 provided along the vehicle width direction. The front sub-frame 14 supports an automatic transmission (not shown) connected to an engine 16 disposed in front of the vehicle body.
[0018]
Front end portions 14A at both ends in the vehicle width direction of the front sub-frame 14 are fixed to the front side of the rear portion 12A of the front side member 12 by fastening members 18 such as bolts. At the rear portion 12A of the front side member 12, a mounting portion 20 that supports a rear end portion 14B at both ends in the vehicle width direction of the front sub-frame 14 is formed.
[0019]
As shown in FIG. 2, a mounting hole 24 through which a bolt 22 as a fastening member is inserted is formed in a lower wall portion 20A of the mounting portion 20 of the front side member 12. The bolt 22 penetrates through a through hole 26 formed at the rear end 14B at both ends in the vehicle width direction of the front sub-frame 14 from below the vehicle, and is inserted into the mounting hole 24. 20 is screwed to a weld nut 28 fixed to the upper surface side of the lower wall portion 20A.
[0020]
As shown in FIG. 3, a long hole 30 as a sub-frame movement control means is formed in the lower wall portion 20 </ b> A of the mounting portion 20 of the front side member 12 so as to be continuous with the mounting hole 24. Extends from the mounting hole 24 obliquely rearward and outward.
[0021]
The width of the front part 30A of the long hole 30 is set smaller than the hole diameter of the mounting hole 24, and the rear part 30B of the long hole 30 is set to be substantially the same as the hole diameter of the mounting hole 24.
Therefore, when a load equal to or more than a predetermined value acts on the bolt 22 from the vehicle front side to the vehicle rear side via the front sub-frame 14, the bolt 22 moves from the mounting hole 24 to the vehicle rear side along the elongated hole 30. It is designed to move toward. On the other hand, when a load equal to or more than a predetermined value acts on the bolt 22 from the front side of the vehicle toward the rear inside of the vehicle via the front sub-frame 14, the bolt 22 does not move along the long hole 30 and the mounting hole 24 And in the vicinity thereof.
[0022]
Next, the operation of the present embodiment will be described.
[0023]
In the present embodiment, as shown in FIG. 4, when the vehicle body 10 collides with the collision body S with a full barrier, the front portions 12B of the left and right front side members 12 are almost equally axially (vehicle longitudinal direction). And the front sub-frame 14 also moves substantially parallel to the rear of the vehicle.
[0024]
As a result, the left and right bolts 22 fixing the rear end portion 14B of the front sub-frame 14 to the attachment portion 20 of the front side member 12 have a load of a predetermined value or more from the vehicle front side to the vehicle rear side. (Arrow F1 in FIG. 4) acts.
[0025]
Therefore, the left and right bolts 22 move toward the rear outside of the vehicle along the long holes 30 from the mounting holes 24 formed in the mounting portions 20 of the rear portion 12A of the front side member 12, respectively. Further, when the left and right bolts 22 reach the rear portion 30 </ b> B of the elongated hole 30, the front sub-frame 14 is separated from the mounting portion 20 of the front side member 12.
[0026]
For this reason, the front sub-frame 14 largely moves toward the vehicle rear side with respect to the front side member 12, so that the collision energy can be sufficiently absorbed at the time of a full barrier frontal collision.
[0027]
The relationship between the deformation stroke S of the vehicle body 10 and the impact acceleration G at this time is as shown by a solid line in FIG. 6, and the front sub-frame 14 is indicated by a two-dot chain line in FIG. On the other hand, the maximum value G1 (G1 <G2) of the impact acceleration G can be reduced as compared with the maximum value G2 of the impact acceleration G when the vehicle does not move backward.
[0028]
On the other hand, as shown in FIG. 5, when the vehicle body 10 collides forward with the collision body S, only the front portion 12B of the front side member 12 on the collision side in the left and right front side members 12 is crushed in the axial direction, and Only the collision side of the front subframe 14 also moves rearward of the vehicle.
[0029]
As a result, of the left and right bolts 22 that fix the rear end portion 14B of the front sub-frame 14 to the mounting portion 20 of the front side member 12, the collision side bolt 22 has a predetermined value toward the rear inside of the vehicle. The above load (arrow F2 in FIG. 5) acts.
[0030]
Therefore, the collision-side bolt 22 does not move along the elongated hole 30 extending obliquely rearward and outward from the mounting hole 24, is held in the mounting hole 24 and the vicinity thereof, and the other bolt 22 is also mounted. It does not move along the elongated hole 30 extending obliquely rearward and outward from the hole 24, and is held in the mounting hole 24 and its vicinity. For this reason, the front subframe 14 slightly moves rearward only on the collision side, but the amount of movement of the front subframe 14 rearward decreases, so that the amount of interference between the engine 14 and the dash panel decreases. The amount of deformation of the cabin can be reduced.
[0031]
As shown in FIG. 7, the shape of the long hole 30 as the subframe movement control means may be the same width from the front part 30A to the rear part 30B.
[0032]
Next, a second embodiment of the front subframe mounting structure of the present invention will be described with reference to FIGS.
[0033]
The same members as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.
[0034]
As shown in FIGS. 8 and 9, in the present embodiment, the sub-frame 20 </ b> A of the mounting portion 20 of the front side member 12 is positioned at a predetermined distance away from the mounting hole 24 toward the vehicle diagonally rearward and outward. A through hole 40 is formed as movement control means.
[0035]
Therefore, when a load equal to or more than a predetermined value acts on the bolt 22 from the vehicle front side to the vehicle rear side via the front sub-frame 14, the bolt 22 breaks the lower wall 20 </ b> A from the mounting hole 24 and It moves toward the side and reaches the through hole 40. On the other hand, when a load equal to or more than a predetermined value acts on the bolt 22 from the vehicle front side toward the vehicle rear inside via the front sub-frame 14, the bolt 22 does not reach the through hole 40, and Is to be held.
[0036]
Next, the operation of the present embodiment will be described.
[0037]
In the present embodiment, similarly to the first embodiment, when the vehicle body 10 makes a full barrier frontal collision with the collision body S, the front portions 12B of the left and right front side members 12 are almost equally crushed in the axial direction, and The sub-frame 14 also moves substantially parallel to the rear of the vehicle.
[0038]
As a result, the left and right bolts 22 fixing the rear end portion 14B of the front sub-frame 14 to the attachment portion 20 of the front side member 12 have a load of a predetermined value or more from the vehicle front side to the vehicle rear side. (Arrow F1 in FIG. 10) acts.
[0039]
Therefore, as shown in FIGS. 10A to 10C, the left and right bolts 22 (only the left bolt 22 when viewed from below the vehicle are shown) are attached to the rear portion 12A of the front side member 12 respectively. The front sub-frame 14 moves from the mounting hole 24 formed in the vehicle 20 toward the rear side of the vehicle and finally reaches the through hole 40, and the front sub-frame 14 is separated from the mounting portion 20 of the front side member 12.
[0040]
For this reason, the front sub-frame 14 largely moves toward the vehicle rear side with respect to the front side member 12, so that the collision energy can be sufficiently absorbed at the time of a full barrier frontal collision.
[0041]
On the other hand, as in the first embodiment, when the vehicle body 10 collides forward with the collision body S, only the front portion 12B of the colliding front side member 12 of the left and right front side members 12 collapses in the axial direction, and Also, only the collision side of the front subframe 14 slightly moves rearward of the vehicle.
[0042]
As a result, of the left and right bolts 22 that fix the rear end portion 14B of the front sub-frame 14 to the mounting portion 20 of the front side member 12, the collision side bolt 22 has a predetermined value toward the rear inside of the vehicle. The above load (arrow F2 in FIG. 11) acts.
[0043]
Therefore, the collision-side bolt 22 does not reach the through hole 40 that is separated from the mounting hole 24 by a predetermined distance toward the diagonally rearward outside of the vehicle, and is held near the mounting hole 24, and the other bolt 22 is also mounted in the mounting hole 24. 24. As a result, the front subframe 14 slightly moves rearward only on the collision side, but the amount of movement of the front subframe 14 rearward decreases, so that the interference between the engine 14 and the dash panel decreases. The amount of deformation of the cabin can be reduced.
[0044]
In the above, the present invention has been described in detail with respect to a specific embodiment, but the present invention is not limited to such an embodiment, and various other embodiments are possible within the scope of the present invention. Some will be apparent to those skilled in the art. For example, the subframe movement control means is not limited to the long hole 30 and the through hole 40 in the above embodiment, and may have another configuration such as a thin portion.
[0045]
【The invention's effect】
According to the first aspect of the present invention, there is provided a front sub-member arranged along a vehicle width direction on a pair of front side members arranged substantially parallel to a vehicle front-rear direction at both ends in a vehicle width direction. A front sub-frame mounting structure for fixing the frame with a fastening member, wherein the mounting portion is formed at a rear portion of the pair of front side members and has a mounting hole through which the fastening member is inserted. When a load equal to or more than a predetermined value acts toward the vehicle rear, the fastening member is moved from the mounting hole to the vehicle rear side, and when a load equal to or more than the predetermined value acts on the fastening member toward the vehicle rear inside. Has a sub-frame movement control means for holding the fastening member in the mounting hole and in the vicinity thereof, so that the collision energy is sufficiently absorbed at the time of a full barrier frontal collision, and at the time of an offset frontal collision, An excellent effect of reducing the amount of deformation of the emissions.
[0046]
According to a second aspect of the present invention, in the front subframe mounting structure according to the first aspect, the subframe movement control means is a long hole extending obliquely rearward and outward from the mounting hole. It has an excellent effect of sufficiently absorbing the collision energy and reducing the amount of deformation of the cabin at the time of an offset frontal collision.
[0047]
According to a third aspect of the present invention, in the front sub-frame mounting structure according to the first aspect, the sub-frame movement control means is formed at a position spaced apart from the mounting hole by a predetermined distance toward a vehicle diagonally rearward and outward. Therefore, there is an excellent effect that the collision energy can be sufficiently absorbed at the time of a full barrier head-on collision and the amount of deformation of the cabin can be reduced at the time of an offset head-on collision.
[Brief description of the drawings]
FIG. 1 is a schematic plan view showing a front subframe mounting structure according to a first embodiment of the present invention, as viewed from below a vehicle.
FIG. 2 is an enlarged sectional view taken along line 2-2 of FIG.
FIG. 3 is a perspective view showing a front side member of the front subframe mounting structure according to the first embodiment of the present invention, as viewed obliquely from the front outside and below the vehicle.
FIG. 4 is a schematic plan view showing a full barrier frontal collision state in the front subframe mounting structure according to the first embodiment of the present invention, as viewed from below the vehicle.
FIG. 5 is a schematic plan view showing an offset front collision state in the front subframe mounting structure according to the first embodiment of the present invention, as viewed from below the vehicle.
FIG. 6 is a graph showing the relationship between the deformation stroke of the vehicle body and the impact acceleration at the time of a full barrier frontal collision in the front subframe mounting structure.
FIG. 7 is a perspective view showing a front side member of a front sub-frame mounting structure according to a modification of the first embodiment of the present invention, as viewed obliquely from the front outside and below the vehicle.
FIG. 8 is a perspective view showing a front side member of a front subframe mounting structure according to a second embodiment of the present invention, as viewed obliquely from the front outside and below the vehicle.
FIG. 9 is an enlarged cross-sectional view corresponding to FIG. 2 of a front subframe mounting structure according to a second embodiment of the present invention.
FIGS. 10 (A) and 10 (B) are explanatory views of the operation of the front subframe mounting structure according to the second embodiment of the present invention at the time of a full barrier frontal collision.
FIGS. 11A and 11B are explanatory diagrams of an operation at the time of an offset front collision in a front subframe mounting structure according to a second embodiment of the present invention.
[Explanation of symbols]
12 Front side member 14 Front sub frame 20 Front side member mounting part 22 Bolt (fastening member)
24 mounting hole 30 long hole (sub-frame movement control means)
40 through-hole (subframe movement control means)

Claims (3)

A front sub that fixes a front sub frame disposed along the vehicle width direction to a pair of front side members disposed substantially parallel to the front and rear ends of the vehicle in the vehicle width direction along the vehicle front and rear direction with a fastening member. Frame mounting structure,
A mounting portion formed at a rear portion of the pair of front side members and formed with a mounting hole through which the fastening member is inserted;
When a load of a predetermined value or more is applied to the fastening member toward the rear of the vehicle, the fastening member is moved from the mounting hole toward the rear of the vehicle, and the fastening member is moved to the rear of the vehicle. When a load equal to or more than a predetermined value is applied inward, a sub-frame movement control unit that holds the fastening member in the vicinity of the attachment hole and the attachment hole,
A front subframe mounting structure characterized by having: The front subframe mounting structure according to claim 1, wherein the subframe movement control means is an elongated hole extending obliquely rearward and outward from the mounting hole. The front sub-frame mounting structure according to claim 1, wherein the sub-frame movement control means is a through-hole formed at a predetermined distance from the mounting hole toward a diagonally rearward outside of the vehicle.

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