JP4534991B2 - Body front structure - Google Patents

Description

  The present invention relates to a vehicle body front structure.

  As the vehicle body front structure, various structures that can effectively absorb impacts have been proposed. For example, in Patent Document 1, a component of a load from the front of the vehicle body is applied to the front side member as a downward pulling load via an auxiliary member so as to suppress bending of the front side member to the upper side of the vehicle body. The body structure made is described.

Thus, it is desired to control the folding mode of the side member by effectively applying a downward component force to the side member with respect to the load from the front of the vehicle body.
JP 2004-243785 A

  In view of the above facts, the present invention has an object to obtain a vehicle body front structure capable of controlling a folding mode of a side member by effectively applying a downward component force to the side member with respect to a load from the front of the vehicle body. And

In the first aspect of the present invention, a side member extending in the vehicle front-rear direction, a first standing member standing downward from the side member, and a suspension member connected to the first standing member, The under member extending in the vehicle front-rear direction so as to incline forward and upward from the suspension member, and the suspension member and the under member are arranged such that the upper portion of the under member is closer to the suspension member than the lower portion. Connecting means for connecting so as to be easily deformed, and the buckling strength of the front region, the central region, and the rear region of the under member in the vehicle front-rear direction is greater than the front region in the rear region. It is characterized by being set to be higher and higher in the central region than in the rear region .

In this way, the suspension member and the under member are connected by the connecting means so that the upper part of the under member can be easily deformed in a direction closer to the suspension member than the lower part. Due to the load (impact) applied from above , the upper part of the under member is deformed relative to the lower part relative to the lower part , and the upper part of the connecting means is deformed more easily than the lower part, and is easily displaced toward the rear side of the vehicle. And since the inclination angle of the under member extended in the vehicle longitudinal direction so as to incline toward the front upper direction from the suspension member can be further increased, from the under member through the connecting means, the suspension member, the first standing member, A component force that pulls downward can be applied to the side member. That is, in the present invention, the side member folding mode can be controlled by effectively applying a downward component force to the side member with respect to the load from the front of the vehicle body.
In addition, the buckling strength of the under member is set to be higher in the rear region than in the front region, and higher in the central region than in the rear region . Therefore, the under member can be deformed in the order of the front region, the rear region, and the central region by the load (impact) applied to the front structure of the vehicle body from the front to absorb energy, and the rear portion of the under member moves downward. Deformation (so-called “downward convex folding”) is likely to occur. Then, after the rear portion is displaced before the center portion of the under member and the inclination angle toward the front upper side of the under member is increased, this load can be transmitted to the connecting means.

  The “deformation” referred to here is a modification that further increases the inclination angle of the under member as described above, and the under member is substantially relative to the suspension member at the upper part of the connecting means rather than at the lower part. All deformations that approach

According to a second aspect of the present invention, in the first aspect of the present invention, the connecting means forms a vehicle front-rear direction gap between the suspension member and the under member at the upper portion, and the suspension at the lower portion. It has a coupling member which couples a member and the under member.

That is, between the suspension member and the under member, a connecting means can be realized with a simple structure in which a gap in the vehicle front-rear direction is formed at the upper part and a connecting member is provided at the lower part to connect them.

According to a third aspect of the present invention, in the first or second aspect of the present invention, the front member is erected downward from the side member on the vehicle front side relative to the first erected member, and the front portion of the under member is It has the 2nd standing member connected, It is characterized by the above-mentioned.

  That is, by providing such a second upright member, the under member is restricted from moving up and down on the vehicle front side of the first upright member. Therefore, when a load is applied from the front, the under member is difficult to move up and down on the front side, and the load from the front can be effectively transmitted by the connecting means.

  Since the present invention is configured as described above, the side member folding mode can be controlled by effectively applying a downward component force to the side member with respect to the load from the front of the vehicle body.

  FIG. 1 shows an overall configuration of a vehicle body front structure 12 according to the first embodiment of the present invention. Further, FIG. 2 shows the vehicle body front part structure 12 partially enlarged. In each drawing, the front side of the vehicle is indicated by an arrow FR, and the upper side of the vehicle is indicated by an arrow UP. Hereinafter, the front of the vehicle is simply abbreviated as “front” and the rear of the vehicle is simply abbreviated as “rear”.

  The vehicle body front part structure 12 has a pair of front side members 14 extending in the vehicle front-rear direction at the front part of the vehicle body. The front side members 14 are arranged at predetermined intervals in the vehicle width direction. The front side member 14 includes a front portion 14A that extends substantially horizontally on the front side of the vehicle, an intermediate inclined portion 14B that is continuously inclined from the front portion 14A and obliquely inclined rearward and downward, and an intermediate inclined portion 14B. And a rear portion 14C extending substantially horizontally toward the rear side. When a large external force (load) greater than or equal to a predetermined value is applied from the front side of the vehicle, it deforms as shown by a two-dot chain line in FIG. 42 to absorb energy.

  From the vicinity of the boundary between the front portion 14A of the front side member 14 and the intermediate inclined portion 14B, a bulging portion 14D bulging downward is formed, and the bulging portion 14D has a first connecting member. The upper end of 16 is attached. The first connecting member 16 is erected downward from the bulging portion 14D.

  A suspension member 18 is attached to the lower end of the first connecting member 16. The side member has a structure corresponding to a suspension (not shown) of the vehicle body, and supports a part of the suspension.

  The upper end of the second connecting member 20 is attached to the front end portion of the front portion 14 </ b> A of the front side member 14. The second connecting member 20 includes a standing portion 20A that is erected downward from the front portion 14A of the front side member 14, and a cross member 20B that is disposed at the lower end of the standing portion 20A. .

  Under the front portion 14 </ b> A of the front side member 14, an under member 22 is disposed between the second connecting member 20 and the suspension member 18, and the front portion of the under member 22 is the second connecting member 20. Further, the rear part is connected to the suspension member 18. Therefore, the second connecting member 20, the suspension member 18, and the under member 22 are connected. As can be seen from FIG. 3, the under member 22 is disposed so as to be inclined upward as it goes from the suspension member 18 side, that is, from the rear to the front. Here, the inclination angle of the undermember 22 with respect to the horizontal plane LS is θ.

  As shown in detail in FIG. 4, the under member 22 of this embodiment is configured by two under member constituting members 24 and 26. One under member constituting member 24 has a substantially L-shaped cross section, and the other under member constituting member 26 has a cross section with the under member constituting member 24 so that a cross section in the vehicle width direction forms a substantially rectangular cross section. The flange pieces 26 </ b> A and 26 </ b> B extend from the end portions of the flange portion 26 </ b> A. On the other hand, in the under member constituting member 24, the portions that come into contact with the flange pieces 26A and 26B in the assembled state of the two under member constituting members 24 and 26 are the joining portions 24A and 24B. The two under member constituting members 24 and 26 are joined to each other at the joining portions 24A and 24B and the flange pieces 26A and 26B, for example, by welding or the like, so that the under member 22 having a quadrangular cross section is formed as a whole.

  As shown in FIG. 5, the rear end of the under member 22 faces the suspension member 18 in the vehicle front-rear direction, and the lower portion 22 </ b> L forms a mounting piece 28 in which one or a plurality of bolt insertion holes are formed. . On the other hand, an extension piece 32 is provided from the front end of the suspension member 18 so as to extend downward and bend forward and be formed with a bolt insertion hole. The bolts 36 are inserted into the bolt insertion holes via the brackets 30 and the nuts 38 are fastened, whereby the rear end of the under member 22 is connected to the suspension member 18 at the lower portion 22L. On the other hand, unlike the lower portion 22L, the upper portion 22U at the rear end of the under member 22 is not fixed by a bolt 36 or the like, and a gap 40 is formed between the extended piece 32 and the under member 22.

  As shown in FIG. 6, a connecting piece 42 that extends forward and has one or a plurality of bolt insertion holes (two in the vehicle width direction) from the lower portion 22 </ b> T of the front end of the under member 22. Is formed. On the other hand, a bolt insertion hole is also formed in the lower portion of the second connecting member 20. Bolts 48 are inserted into these bolt insertion holes, and nuts 50 are fastened to the bolts 48 so that the front end of the under member 22 is connected to the second connecting member 20.

As shown in FIGS. 1, 3, and 4, the under member 22 has three regions (a front region 22 </ b> A, a center region 22 </ b> B, and a rear region 22 </ b> C) set in the extending direction, that is, the vehicle longitudinal direction. Has been. And regarding the buckling strength of each of these regions,
Front area 22A <rear area 22C <central area 22B (1)
Each buckling strength is set so as to hold. With respect to the front region 22A, the buckling strength is set high so that the load 40 is transmitted backward and the gap 40 is eliminated before the front region 22A buckles. Therefore, when a load from the front acts, the under member 22 first transmits this load to the rear to eliminate the gap 40, and then deforms in the order of the front region 22A, the rear region 22C, and the central region 22B. Of course, depending on the magnitude of the load, the central region 22B and the rear region 22C may not be deformed.

  In addition, the specific structure which sets three area | regions where buckling strength differs in this way to the under member 22 is not specifically limited. In the present embodiment, as shown in FIG. 4, a notch 52 is formed in the joint portion 24A and the flange piece 26A corresponding to the front region 22A to reduce the buckling strength of the front region 22A. . Further, in a portion corresponding to the rear region 22C, a hole 54 is formed in the upper surface portion of the under member constituting member 24, and the buckling strength of the rear region 22C is set between the front region 22A and the central region 22B. ing.

  Next, the operation of this embodiment will be described.

  When an external force (impact) is not applied from the front of the vehicle, as shown in FIGS. 1 and 3 (shown by a solid line in FIG. 2), the under member 22 is not deformed and the front side member 14 is not deformed. Is not deformed. Further, as shown by the solid line in FIG. 5, the under member 22 does not move rearward, and the gap 40 between the under member 22 and the suspension member 18 is also maintained.

  When a load acts from the front of the vehicle and a part of the load is input to the under member 22, the under member 22 transmits this load to the rear. As a result, the under member 22 moves rearward to deform the extension piece 32, and the gap 40 is eliminated as shown by a two-dot chain line in FIG. Then, as shown by a two-dot chain line in FIG. 2, the inclination angle θ of the under member 22 toward the front upper side is increased. Next, since the under member 22 has a buckling strength set as in (1) above, the front region 22A is first deformed, and then the rear region 22C is deformed to absorb energy. At this time, since the inclination angle θ of the under member 22 has already increased, a deformation (so-called “downward fold”) in which the rear portion of the under member 22 moves downward is likely to occur.

  On the other hand, the front side member 14 is also deformed as shown by a two-dot chain line in FIG. At this time, an upward force F1 acts on the rear end portion of the front portion 14A of the front side member 14, particularly on the portion where the bulging portion 14D is formed. On the other hand, since the under member 22 is in the state in which the inclination angle θ is increased as described above, a force F <b> 2 having a downward component is generated at the connection portion between the under member 22 and the suspension member 18. And this force F2 acts on the site | part in which the bulging part 14D of the front side member 14 was formed through the suspension member 18. FIG. Since the downward force F2 has a component opposite to the aforementioned force F1, the front side member 14 has a portion near the rear end portion of the front portion 14A as shown by a two-dot chain line in FIG. The upward displacement is suppressed, and the part is deformed so as to sink downward in this part. That is, in the present embodiment, the folding mode of the front side member 14 can be controlled by applying a force F2 that cancels the force F1 that originally acts on the front side member 14.

  In particular, in the present embodiment, the front portion of the under member 22 is connected to the second connecting member 20 erected downward from the front end of the front side member 14. For this reason, it is difficult for the under member 22 to be displaced in the vertical direction at the front portion when a load is applied, and the load from the front can be effectively transmitted to the rear.

  Note that a toe board 56 may be disposed behind the intermediate inclined portion 14B of the front side member 14 as shown in FIGS. In this embodiment, as can be seen from FIG. 2, when the front side member 14 is deformed, the intermediate inclined portion 14B is displaced downward, that is, in a direction away from the toe board 56, so that the toe board 56 is inadvertently moved backward. This can be suppressed. Of course, even in a configuration in which a member other than the toe board 56 is arranged, it is possible to prevent the member from being carelessly moved rearward.

  Further, in this embodiment, the vibration of the front side member 14 and the suspension member 18 is suppressed by the structure of the front side member 14 and the under member 22 described above. It becomes possible to reduce vibration. For example, it is possible to reduce the sound of noise generated in the passenger compartment.

  In addition, the specific structure which sets the buckling strength of the under member 22 so that the said Formula (1) may be satisfy | filled is not specifically limited to said thing, For example, the structure of each embodiment shown below is employable. In the following, the same components and members as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

In the under member 62 of the second embodiment shown in FIG. 7 (A), as can be seen from a comparison between FIGS. By reducing the cross-sectional force at the point you want to reduce,
Front area 62A <rear area 62C <center area 62B
The buckling strength to be obtained is obtained. In particular, since the cross-sectional shape can be continuously changed, the buckling strength can also be continuously changed.

In the under member 72 of the third embodiment shown in FIG. 8, the reinforcing member 74 is disposed inside (inside the under member constituting members 24 and 26 shown in FIG. 4 as the first embodiment). The presence or absence of the reinforcement member 74 is adjusted in accordance with the strength. That is, in the front region 22A, the reinforcing member 74 is substantially not disposed in the front half portion 72D, and in the rear region 22C, the portion 72E where the reinforcing member 74 is not disposed in a part in the vehicle front-rear direction. Is set. In the central region 22B, the reinforcing member 74 is disposed in the entire vehicle longitudinal direction. And this
Front area 72A <rear area 72C <central area 72B
The buckling strength that satisfies the above is obtained.

In the under member 82 of the fourth embodiment shown in FIG. 9, a portion 82D where the reinforcing member 74 is not provided is set for the front region 22A, as in the third embodiment. In the rear region 22C, the reinforcing member 74 is disposed over the entire region, but a notch 84 is formed so that the buckling strength is lower than that of the central region 22B and higher than that of the front region 22A. And this
Front area 82A <rear area 82C <center area 82B
The buckling strength that satisfies the above is obtained.

  Further, in each of the above embodiments, as the coupling member (coupling means) of the present invention, an example in which a gap is formed at the upper part of the coupling portion between the under member and the suspension member is described. A structure in which the upper part is connected (no gap is provided) so as to be easier to deform than the lower part may be used. However, it is preferable to provide a gap in the upper portion as in each of the embodiments described above, because resistance when the undermember is displaced so as to increase the inclination angle θ is smaller than in the configuration in which the upper portions are connected.

  Further, even if the rear end of the under member and the suspension member do not necessarily face each other, it is only necessary that the upper portion of these connecting portions is relatively easily deformable than the lower portion.

1 is a side view schematically showing a vehicle body front structure according to a first embodiment of the present invention in a state before deformation. It is a side view which expands partially and shows the vehicle body front part structure of 1st Embodiment of this invention. It is a side view which shows the under member of the vehicle body front part structure of 1st Embodiment of this invention, and its vicinity. It is a perspective view showing roughly an under member of a body front part structure of a 1st embodiment of the present invention. It is explanatory drawing which shows the connection structure of the under member and suspension member in the vehicle body front part structure of 1st Embodiment of this invention. It is explanatory drawing which shows the connection structure of the under member and 2nd standing member in the vehicle body front part structure of 1st Embodiment of this invention. (A) is a side view which shows the under member of the vehicle body front part structure of 2nd Embodiment of this invention, and its vicinity, (B) is the BB sectional drawing of (A), (C) is (A). It is CC sectional view taken on the line. It is a side view which shows the under member of the vehicle body front part structure of 3rd Embodiment of this invention, and its vicinity. It is a side view which shows the under member of the vehicle body front part structure of 4th Embodiment of this invention, and its vicinity.

Explanation of symbols

12 Car body front structure 14 Front side member 14A Front part 14B Middle inclined part 14C Rear part 14D Swelling part 16 First connecting member (first standing member)
18 Suspension member 20 Second connecting member (second standing member)
22 under member 22A front region 22B central region 22C rear region 24 under member constituent member 24A joint portion 26 under member constituent member 26A flange piece 28 mounting piece 30 bracket 32 extending piece 36 bolt (connecting means, connecting member)
38 Nut (connecting means, connecting member)
40 Gap 42 Connection piece 48 Bolt 50 Nut 52 Notch 54 Hole 56 Toe board 62 Under member 62A Front region 62B Central region 62C Rear region 72 Under member 72A Front region 72B Central region 72C Rear region 74 Reinforcement member 82 Under member 82A Front Region 82B Central region 82C Rear region 84 Notch LS Horizontal plane θ Inclination angle

Claims (3)

A side member extending in the longitudinal direction of the vehicle,
A first standing member standing downward from the side member;
A suspension member coupled to the first standing member;
An under member extending in the vehicle front-rear direction so as to incline forward and upward from the suspension member;
Coupling means for coupling the suspension member and the under member so that the upper part of the under member is easily deformed in a direction closer to the suspension member than the lower part ;
Have
The buckling strength of the front region, the central region, and the rear region of the under member in the vehicle front-rear direction is set to be higher in the rear region than in the front region, and higher in the central region than in the rear region. The vehicle body front structure characterized by being made. The connecting means is
A coupling member that forms a vehicle front-rear direction gap between the suspension member and the under member in the upper part and couples the suspension member and the under member in the lower part;
The vehicle body front part structure according to claim 1, comprising: A second standing member that is erected downward from the side member on the vehicle front side relative to the first standing member, and a front portion of the under member is connected;
The vehicle body front part structure according to claim 1 or 2, characterized by comprising:

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