JP7201145B2 - vehicle front structure - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle front structure having a front side member that absorbs an impact due to a load from the front.

BACKGROUND ART Conventionally, in a vehicle front structure, when a collision load is applied to the front of the vehicle, the front side member is buckled to absorb the impact. For example, in the vehicle front structure of Patent Literature 1, the front side member has a front deformation portion, an inner weakness, and an outer weakness in order from the front. When a load is applied to the front part of the vehicle, the front side member absorbs the load by deforming the front deforming part in order, then bending at the inner weak point, and finally bending at the outer weak point. In this way, by transmitting the load to the rear of the front side member while absorbing the impact, the deformation of the front portion of the vehicle can be controlled.

JP 2009-255883 A

In a vehicle with a narrow engine room, such as a small car, if this deformation is not properly controlled, the deformation may extend to the passenger compartment. Therefore, in order to cause the front side members to buckle in order from the front at the time of a frontal collision, the rigidity breaking points provided in the front side members are set so as to decrease in order from the front side. Here, in order to secure a large amount of impact absorption, it is preferable to set the front rigidity breaking point as small as possible. However, the rigidity breaking point on the rear side becomes too small, and at the rigidity breaking point on the rear side, the buckling may not occur as designed. As a countermeasure, it is conceivable to separately provide a reinforcing member, but there are problems such as an increase in cost, an increase in weight, and deterioration in productivity.

SUMMARY OF THE INVENTION In view of the above, it is an object of the present invention to provide a vehicle front structure capable of controlling buckling of a front side member by ensuring buckling even at a small rigidity breaking point.

In the vehicle front structure of the present invention, the front side member extending in the longitudinal direction of the vehicle body includes a side member inner having a hat-shaped cross section with one side open and a flat side member outer closing the opening of the side member inner. A plurality of rigid breaking points for causing deformation of the front side member are provided on the front side of the side member inner, and the side member outer is formed by connecting a plurality of plate materials, and the connecting portion where the plate materials are connected is set according to the position of the rigid breaking point of the side member inner.

A joint formed when two plates are joined has low rigidity and is easily deformed. If this connecting portion is provided in accordance with the position of the rigid breaking point of the side member inner, deformation such as buckling or bending due to a load from the front is likely to occur at this portion.

According to the present invention, by providing the connecting portion of the plate member facing the rigid breaking point for causing the deformation of the front side member, the front side member can be reliably buckled by the load from the front. The buckling of the side member can be controlled, and the deformation can be stabilized.

1 is a side view of a front side member to which a vehicle front structure according to an embodiment of the present invention is applied, viewed from outside the vehicle; FIG. Perspective view of front side member of front side member Exploded perspective view of front side member Top view of front side member Side view of the front side member seen from the inside of the vehicle Diagram showing other forms of rigid breakpoints and joints

An engine room that accommodates a power unit such as an engine is arranged in the front portion of a vehicle to which the vehicle front portion structure of the embodiment of the present invention is applied. As shown in FIG. 1, front side members 1 are provided on both left and right sides of the engine room in the vehicle width direction. The front side member 1 extends in the longitudinal direction of the vehicle.

A suspension member 2 is provided below a front side member 1, the front side of the suspension member 2 is supported by the front side member 1 via a bracket 3, and the rear side is bolted to the front side member 1. - 特許庁A suspension tower 4 that supports a shock absorber (not shown) is provided above the front side member 1 .

The front side member 1 is composed of a front side member 10 arranged in front of the dash panel 5 and a rear side member 11 connected to the front side member 10 and arranged under the floor of the passenger compartment. Configured. A crash box 12 is attached to the front end of the front side member 1 .

The rear side member 11 is positioned lower than the front side member 10 and is displaced in a direction perpendicular to the front-rear direction, that is, in the vertical direction. Therefore, the front side member 1 is bent downward from the front side member 10 to the rear side member 11 . In order to connect to the front side member 10 , the front side of the rear side member 11 is bent to form an inclined portion 13 . The inclined portion 13 is formed obliquely downward toward the rear of the vehicle. The front side member 10 and the rear side member 11 are joined by spot welding at a joining portion 14 where the front end of the inclined portion 13 and the rear end of the front side member 10 are overlapped.

As shown in FIGS. 2 to 5, the front side of the front side member 10 is provided with a plurality of rigid breaking points for deforming the front side member 1 such as buckling and bending. A rigid breaking point is defined as a portion whose rigidity is different from that of other portions, and serves as a starting point for deformation such as buckling and bending. As such a rigidity breaking point, a fragile portion 15 is provided so that the rigidity is lower than that of other portions. By appropriately setting the position of the fragile portion 15, it is possible to control buckling such as buckling timing and buckling amount.

As shown in FIG. 3 , the front side member 10 of the front side member 1 includes a side member inner 20 having a hat-shaped cross section and an outer side in the vehicle width direction, and a flat side member closing the opening of the side member inner 20 . It is formed in a hollow shape by the outer. Outer flanges 22 are formed in the front-rear direction on upper and lower portions of the side member inner 20 . The side member outer 21 is overlaid on the outer flange 22, and the side member inner 20 and the side member outer 21 are joined by spot welding.

As shown in FIGS. 4 and 5, the fragile portion 15 of the front side member 10 is a bead perpendicular to the front-rear direction, which is the starting point of crushing deformation at the time of collision. A plurality of lateral groove-shaped lateral beads 23, here three lateral groove-shaped lateral beads 23a, 23b, and 23c, are formed on the upper and lower surfaces of the side member inner 20 at equal intervals from one end to the other in the left-right direction. . The horizontal beads 23a, 23b, 23c on the lower surface are arranged so as to face the horizontal beads 23a, 23b, 23c on the upper surface. A large lateral bead 23a, a medium lateral bead 23b, and a small lateral bead 23c are arranged in order from the front side. The large transverse bead 23a is the widest and deepest. The width becomes narrower and shallower as it becomes the middle lateral bead 23b and the small lateral bead 23c. The wider and deeper the horizontal bead 23 is, the easier it is to be crushed and deformed by the load from the front. That is, the amount of impact absorption is small. The number of horizontal beads 23 is not limited to three on each side.

A vertical bead 25 in the shape of a vertical groove is also formed as a weakened portion on the side surface of the side member inner 20 on the vehicle interior side. The large, medium and small vertical beads 25a, 25b, 25c are formed in the same manner as the horizontal beads 23. As shown in FIG. The small vertical bead 25c is formed in a vertically elongated recess that does not reach the upper and lower surfaces.

Notches 26 are formed in the upper and lower outer flanges 22 of the side member inner 20 so as to correspond to the respective lateral beads 23 . Large, medium and small curved portions 27 are formed in the upper and lower outer flanges 22 corresponding to the respective longitudinal beads 25 . The curved portion 27 is recessed toward the cabin side. These notches 26 and curved portions 27 are also provided as weakened portions to control buckling.

As shown in FIG. 3, the side member outer 21 of the front side member 10 is formed by connecting two plate materials. A front plate member 30 located on the front side has a rear flange 31 formed at its rear end, and a rear plate member 32 located on the rear side has a front flange 33 formed at its front end. Both flanges 31 and 33 projecting outward in the vehicle width direction are put together and spot-welded or bolted to form a connecting portion 34 . The front plate member 30 and the rear plate member 32 are connected to form one side member outer 21. - 特許庁The crash box 12 is attached to the front flange 35 of the front plate 30 by spot welding or bolts. The front plate member 30 is a low-strength steel plate, and the rear plate member 32 is a high-strength steel plate. As a result, even if the thicknesses of the plate members 30 and 32 are the same, the rigidity of the front plate member 30 is lower than the rigidity of the rear plate member 32 .

A connecting portion 34 where the front plate member 30 and the rear plate member 32 are connected is set in accordance with the position of the fragile portion 15 . A rear flange 31 of the front plate member 30 and a front flange 33 of the rear plate member 32 are overlapped to form a connecting portion 34 . The connecting portion 34 is arranged so as to face the small horizontal bead 23c. Therefore, the longitudinal lengths of the front plate member 30 and the rear plate member 32 are determined according to the position of the small horizontal bead 23c. Since the connecting portion 34 has low rigidity, it is easily deformed, that is, easily buckled. By aligning the connecting portion 34 with the small horizontal bead 23c, buckling is facilitated at this location. Therefore, even very small beads can be buckled and the buckling can be controlled.

A plurality of vertical groove-like curved portions 36 are formed in the side member outer 21 . The large, medium and small curved portions 36 are provided corresponding to the curved portions 27 of the side member inner 20 . The front plate member 30 has large and medium curved portions 36 corresponding to the large and medium curved portions 27 of the side member inner 20 , and the rear plate member 32 has small curved portions 36 of the side member inner 20 . It is formed corresponding to the curved portion 27 . As a result, the outer flange 22 of the side member inner 20 and the side member outer 21 are in close contact with each other. The curved portion 36 of the side member outer 21 becomes a weak portion and a starting point of deformation.

A plurality of longitudinal beads 40 are formed on the outer surface of the front plate member 30 . A vertically intermediate portion of the two vertical beads 40 protrudes outside the vehicle to form a pedestal 41 for attaching other members such as a harness clamp. The two pedestals 41 are arranged side by side in the front-rear direction. The front pedestal 41 is provided at a position corresponding to the large lateral bead 23a of the side member inner 20, and the rear pedestal 41 is provided at a position corresponding to the middle lateral bead 23b. A mounting hole 42 is formed in the longitudinal bead 40 . By providing the pedestal 41 bulging outward in this way, it functions as a weakened portion, and the front side of the front side member 10 is easily buckled, so that the buckling can be easily controlled.

When a frontal collision occurs, a load is applied to the front side member 1 from the front. First, the crash box 12 is crushed. Then, the front side of the front side member 10 is crushed and deformed by the plurality of fragile portions 15 provided in the front side member 10 . Depending on the size of the horizontal bead 23 and the vertical bead 25 of the front side member 10, the bead on the front side is sequentially buckled, and the front side of the front side member 10 is stably deformed. This provides a large amount of shock absorption.

In order to increase the amount of shock absorption on the front side of the front side member 1, it is preferable to reduce the size of each bead of the fragile portion 15 as a whole. At this time, the bead on the rear side becomes minimal. Therefore, by providing the connecting portion 34 in the side member outer 21 and arranging the connecting portion 34 in accordance with the extremely small bead, even the extremely small bead can be reliably buckled, and the deformation of the front side member 10 can be prevented. can be stabilized. Therefore, when applied to a vehicle such as a compact car in which the front side member 1 cannot be long, the buckling of the front side member 1 can be appropriately controlled, and the front side member 1 can be stabilized while efficiently absorbing impact. can be transformed into, and the influence on the passenger compartment can be avoided. In addition, since the deformation can be stabilized only by processing the front side member 1, there is no need to add a reinforcing member, thereby avoiding an increase in cost, weight, and deterioration of productivity.

It should be noted that the present invention is not limited to the above-described embodiments, and of course many modifications and changes can be made to the above-described embodiments within the scope of the present invention. As the fragile portion 15, the thickness of the front side member 10 may be reduced to form a longitudinal groove or a lateral groove. The side member outer 21 may be formed of three or more plate materials, and a plurality of connecting portions 34 are provided in alignment with the lateral beads 23 respectively.

In the above-described embodiment, buckling of the front side member 1 can be controlled by matching the weak portion 15 with low rigidity with the connecting portion 34 with low rigidity. Alternatively, a high-rigidity joining portion may be aligned with a high-rigidity breaking point. As shown in FIG. 6 , by attaching the patch 50 to the side member inner 20 , the strength is increased locally, and a rigid breaking point 51 with high rigidity is provided. The front end of the patch 50 becomes the starting point of deformation of the front side member 1 . When connecting the front and rear plate members 30 and 31, the front and rear plate members 30 and 31 are overlapped and joined by welding such as spot welding, laser welding, fillet welding, or by bolting to form a joint portion 34 with high rigidity. be done. The position of the connecting portion 34 is set according to the front end of the patch 50 . With such a structure in which the connecting portion 34 is aligned with the rigid breaking point 51, deformation of the front side member 1 can be suppressed even when a load is applied. Therefore, the deformation of the front side member 1 can be controlled by applying this structure to a portion that should not be deformed.

1 front side member 10 front side member 11 rear side member 13 inclined portion 14 joint portion 15 fragile portion 16 reinforcing portion 20 side member inner 21 side member outer 23a large lateral bead 23b medium lateral bead 23c small lateral bead 30 front plate material 31 rear Plate material 34 Joint part 40 Vertical bead 41 Pedestal 45 Reinforcement bead 46 Concave bead

Claims (1)

A front side member extending in the front-rear direction of the vehicle body is formed by a side member inner having a hat-shaped cross section with one side open and a flat side member outer closing the opening of the side member inner. The side member outer is formed by connecting a plurality of plate materials , a flange is formed at the end of each plate material, and a connection portion is formed by joining the flanges together to form a side member outer. A vehicle front structure , wherein the member inner has a rigid breaking point at a position facing the joint .

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