JP2007131135A - Front structure of vehicle body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain front structure of a vehicle body having both of repairability in the case wherein the energy applied from a front side is small and energy absorbing performance in the case wherein the energy applied from the front side is large. <P>SOLUTION: Length of a fitting plate part 24, which is extended from a front end of a side rail 22, in the back and forth direction of a vehicle is decided so that a predetermined gap S1 is structured between a front end part 30T of a main body part 30 of the side rail 22 and a cross member 20. Furthermore, in the case wherein external force (load) is applied to the cross member 20 from a front side of the vehicle, strength of the fitting plate part 24 is decided so that the fitting plate part 24 is deformed to eliminate the gap before the main body part 30 of the side rail 22 is bent. In the case wherein the external force applied from the front side of the vehicle is small, the only fitting plate part 24 is deformed to eliminate the gap S1, and repairability is improved. In the case wherein the external force is large, the main body part 30 and a front side member 14 are deformed to surely absorb the energy. <P>COPYRIGHT: (C)2007,JPO&INPIT

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, the lower stringer is supported below the upper stringer, the lower stringer is provided with a portion having a different reduction ratio, and the shock absorber is provided between the upper stringer and the bumper. A car with a is described.

By the way, in the vehicle body front structure, it is required to satisfy both the repairability (easiness of repair) when the energy applied from the front is small and the energy absorbability when the energy is large.
Special table 2003-513856 gazette

  In view of the above facts, an object of the present invention is to obtain a vehicle body front structure that achieves both repairability when energy applied from the front is small and energy absorption when energy is large.

  In the first aspect of the present invention, the pair of front side members extending in the vehicle front-rear direction at the front portion of the vehicle body, the pair of connecting members extending downward from the respective front portions of the front side member, and the pair A cross member for connecting the connecting members in the vehicle width direction, a pair of side rails disposed below each of the pair of front side members, and a rear of each of the pair of side rails, A suspension member connected to the rear part and the side rail are connected to the cross member by creating a gap between the front part of the side rail and the cross member. A connecting part that is deformed so that the gap is eliminated, and provided on the side rail, and less when buckling the side rail Also it characterized that a part has, and inducing portion that induces the deformation so as to move in a direction away from said front side member.

  Therefore, the connecting portion is deformed so that the gap between the front portion of the side rail and the cross member is eliminated by an external force (impact) acting on the front structure of the vehicle body from the front. Energy can be absorbed by this deformation, and deformation of members other than the side rail can be prevented. Therefore, when repairing, only the side rails need to be replaced, and the repairability is improved.

  Then, after the clearance between the front portion of the side rail and the cross member is eliminated, the side rail is buckled, and this external force further reaches the front side member and the like, and can absorb energy by deformation of the front side member.

  Moreover, at least a part of the side rail moves in a direction away from the front side member during buckling due to the inducing portion provided on the side rail. Thereby, the malfunction which arises when the whole side rail approaches the front side member can be prevented. For example, the engine unit can be prevented from moving to the front side member side (vehicle compartment side).

  According to a second aspect of the present invention, in the first aspect of the present invention, the connection portion is a one-surface connection portion that connects the side rail to the cross member by one surface extending from the side rail. It is characterized by.

  Thus, by connecting the side rail to the cross member by the one-surface connecting portion, the connecting portion can be deformed with a simple structure.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, the side rail is connected to the cross member by a bolt at the connecting portion.

  This facilitates replacement of the side members, further improving repairability.

  According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, the connecting member or a part of the cross member is positioned on the vehicle front side relative to the front side member. It is characterized by that.

  That is, with such a simple structure, a load from the front of the vehicle is first applied to the cross member via the connecting member or the cross member, so that the connecting portion can be reliably deformed.

  Since this invention was set as the said structure, it can be compatible with the repairability when the energy which acted from the front is small, and the energy absorptivity when energy is large.

  FIG. 1A shows an overall configuration of a vehicle body front structure 12 according to an embodiment of the present invention. Further, FIG. 1B shows the vehicle body front 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.

  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. When a large external force (load) of a predetermined value or more acts from the front side of the vehicle, the front side member 14 is deformed as shown in FIG.

  A connecting member 16 is fixed to each front end portion 14T of the front side member 14 by welding or the like. The connecting member 16 extends downward from the front end portion 14T of the front side member 14.

  A portion on the front side of the lower end portion 16 </ b> B of the connecting member 16 is a front protruding portion 18 positioned on the front side of the front end portion 14 </ b> T of the front side member 14.

  A cross member 20 is fixed to the lower end of the connecting member 16 by welding or the like. The cross member 20 connects the connecting member 16 in the vehicle width direction.

  A pair of side rails 22 is disposed below the front side members 14 corresponding to the front side members 14. A plate-like mounting plate portion 24 extends forward from the front end of the side rail 22. As shown in detail in FIG. 2, one or a plurality of screw holes 26 (two in the embodiment, spaced apart in the vehicle width direction) are formed in the mounting plate portion 24. And it is connected with the cross member 20 with the bolt 28, and is what is called a one-side fastening.

  Further, the mounting plate portion 24 is arranged in the vehicle longitudinal direction so that a predetermined gap S1 is formed between the front end portion 30T of the main body portion 30 (portion other than the mounting plate portion 24) of the side rail 22 and the cross member 20. The length of is decided.

  Further, when an external force (load) is applied to the cross member 20 from the front side of the vehicle, the mounting plate portion 24 is before the main body portion 30 of the side rail 22 is buckled, that is, the main body portion 30 of the side rail 22. The strength is set so that the clearance S1 is eliminated by deformation in the vehicle longitudinal direction smaller than the force required for buckling (see FIGS. 3B and 4B).

  The main body portion 30 of the side rail 22 is further buckled after the mounting plate portion 24 is deformed by an external force in the vehicle longitudinal direction. The main body portion 30 is formed with a triggering portion 32 that induces deformation such that at least part of the main body portion 30 moves downward in a direction away from the front side member 14 during buckling. As a specific configuration of the inducing portion 32, a configuration in which a local cut is made in the upper portion of the side rail 22 or the side rail 22 is locally thinned can be given.

  A suspension member 34 is disposed behind the side rail 22 and is fixed to a rear end portion of the side rail 22 by a bolt or the like (not shown).

  Next, the operation of this embodiment will be described.

  When an external force (impact) is not applied from the front of the vehicle, that is, in the normal state, as shown in FIGS. 1A and 1B, the mounting plate portion 24 is not deformed and the gap S1 is also maintained. . Further, the side rail 22 and the front side member 14 are not deformed.

  When an external force is applied from the front of the vehicle, the front projecting portion 18 of the lower end portion 16B of the connecting member 16 is positioned in front of the front end portion 14T of the front side member 14, so first acts on the front projecting portion 18. .

  Here, when the external force is small, that is, when the external force is not enough to buckle the body portion 30 of the side rail 22, the clearance S1 is eliminated as shown in FIGS. 3 (A) and 3 (B). The mounting plate portion 24 is deformed so as to be (or shortened), thereby absorbing energy. As described above, energy is absorbed by the deformation of the mounting plate portion 24, so that no load acts on the front side member 14, the connecting member 16, and the cross member 20. Therefore, when the vehicle body front part structure is repaired after the external force is applied, only the side rail 22 needs to be replaced. Therefore, the repairability is improved as compared with the configuration in which the front side member 14 needs to be replaced.

  When the external force is large, that is, when the body portion 30 of the side rail 22 is buckled, the body portion is deformed after the mounting plate portion 24 is deformed, as shown in FIGS. 30 buckles and the front side member 14 is also deformed. In this way, by deforming the side rails 22 and the front side members 14 in addition to the mounting plate portion 24, even large energy can be reliably absorbed.

  Moreover, in this embodiment, the induction | guidance | derivation part 32 is formed in the side rail 22, and when the side rail 22 buckles, the side rail 22 is moved partially downward in this part. Depending on the deformation of the mounting plate portion 24, the vicinity of the front end of the body portion 30 of the side rail 22 is often buckled so as to be displaced upward, but even in this case, the vicinity of the inducing portion 32 is surely lowered. Move to. Thus, it is possible to prevent the buckled side rail 22 from pressing the other members at the front of the vehicle body into the vehicle interior. For example, an engine unit is often arranged at the front part of the vehicle body, and the engine unit is moved upward by the buckled side rail 22 by making the arrangement position of the engine unit correspond to the position of the induction part 32. Can be prevented from being pressed and reliably moved downward.

  In the above description, an example of a so-called single-surface fastening structure using the mounting plate portion 24 configured by one surface is given as an example of the connecting portion of the present invention. If possible, the connecting portion of the present invention is not limited to such one-side fastening. However, one side fastening is preferable for the following reasons.

  FIG. 5B shows the relationship between the deformation stroke (S) and the load (F) of the side rail 22 in the case of one-surface fastening as in this embodiment. Further, in FIG. 5A, the front end portion 30T (see FIG. 2) of the main body portion 30 of the side rail 22 is not entirely fixed, that is, the cross member 20 is not formed with a gap S1. The relationship between the deformation stroke and the load in a fixed structure (hereinafter referred to as “multi-surface fastening”) is shown. In these graphs, attention is paid to four ridge lines R of the side rail 22 (only three lines are shown in FIG. 3), and a load per one of these ridge lines R is set as a reference value f.

  In the case of multi-surface fastening, as can be seen from FIG. 5A, the load f per ridge line R is simply added by the four ridge lines R, and a load of 4f acts as a whole.

  On the other hand, in the case of one-side fastening, as shown in FIG. 5B, the load f acts on the lower ridge line R1 corresponding to the mounting plate portion 24, and the two lower ridge lines R1 are two. Are added to 2f (see the curve indicated by the alternate long and short dash line). Then, in the middle of the deformation, the load f is applied corresponding to the upper ridgeline R2, and this is also added by the two ridgelines to become 2f (see the curve shown by the two-dot chain line). Since these loads are generated with a time shift, when considering the four ridge lines R, the peak is smaller than 4f which is a peak in the case of multi-surface fastening.

  When the external force is small, only the mounting plate 24 is deformed, that is, the load is applied only to the hatched portion in the graph of FIG.

  In addition, when the external force is large, as described above, the buckling timing differs between the ridgeline R1 and the ridgeline R2, but the load required for buckling does not change. There is almost no difference in the amount of energy.

  As described above, in the single-sided fastening structure, not only the energy absorption when the external force is small is easy, but also the same amount of energy absorption as in the multiple-sided fastening can be obtained with a smaller load. Therefore, it is preferable.

  In addition, as a structure for attaching the side rail 22 to the cross member 20 by the attachment plate portion 24, the fastening structure by the bolt 28 is described above. However, the structure is not limited to the bolt 28 as long as it can be reliably attached. There may be. However, in welding or bonding, it is difficult to remove or attach the side rail 22 from the cross member 20 as compared to fastening with the bolts 28. In this respect, the fastening structure by the bolt 28 is preferable because it can be easily detached and attached.

  The length of the gap S1 is not particularly limited, but by appropriately setting the length of the gap S1, the amount of energy absorbed by the deformation of the mounting plate portion 24, in other words, the load curve at the time of deformation can be freely set. Can be set.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view schematically showing a vehicle body front structure according to an embodiment of the present invention in a state before deformation, where (A) is an overall view and (B) is a partially enlarged view. It is a perspective view which shows the front part of the side rail which comprises the vehicle body front part structure of one Embodiment of this invention. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view schematically showing a vehicle body front structure according to an embodiment of the present invention in a state in which a gap is eliminated, (A) is an overall view, and (B) is a partially enlarged view. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view schematically showing a vehicle body front structure according to an embodiment of the present invention in a state where a side rail and a front side member are deformed, in which (A) is an overall view, and (B) is a partially enlarged view. It is a graph which shows the relationship between the stroke of a deformation | transformation of a side rail, and a load, (A) is the case of multi-surface fastening, (B) is the case of single-surface fastening.

Explanation of symbols

12 Car body front structure 14 Front side member 14T Front end portion 16 Connecting member 16B Lower end portion 18 Front protruding portion 20 Cross member 22 Side rail 24 Mounting plate portion 26 Screw hole 28 Bolt 30 Body portion 30T Front end portion 32 Inducing portion 34 Suspension member R Ridge line R1 Ridge line R2 Ridge line S1 Clearance

Claims (4)

A pair of front side members extending in the longitudinal direction of the vehicle at the front of the vehicle body;
A pair of connecting members extending downward from the respective front portions of the front side members;
A cross member for connecting the pair of connecting members in the vehicle width direction;
A pair of side rails disposed below each of the pair of front side members;
A suspension member disposed behind each of the pair of side rails and connected to the rear portion of the side rails;
It is provided on the side rail and creates a gap between the front part of the side rail and the cross member to connect the side rail to the cross member and deforms so that the gap is eliminated by an external force acting from the front. A connecting portion;
An induction part that is provided on the side rail and induces deformation so that at least a part moves in a direction away from the front side member when the side rail buckles;
The vehicle body front part structure characterized by having. The connecting portion is
A one-surface connecting portion that connects the side rail to the cross member by one surface extending from the side rail;
The vehicle body front part structure according to claim 1, wherein   The vehicle body front part structure according to claim 1 or 2, wherein the side rail is connected to the cross member by a bolt in the connecting portion.   The vehicle body front part structure according to any one of claims 1 to 3, wherein a part of the connecting member or the cross member is located on the vehicle front side with respect to the front side member. .

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