Vehicle body frontal structure

A vehicle body frontal structure includes a bumper face extending in a widthwise direction of a vehicle, a bumper beam disposed behind the bumper face and extending in the widthwise direction of the vehicle; and an energy absorbing member disposed between the bumper face and the bumper beam, formed in a hollow cross sectional shape of which a rear portion is left open, and having an open edge portion that is joined to the bumper beam, so as to deform and absorb collision energy when the collision energy in a rearwards direction of the vehicle is applied to the bumper face. The open edge portion includes cutaway portions which leave portions of the open edge portion as joining leg portions to the bumper beam, and the joining leg portions are provided with deformation guide portions which, in the initial period of deformation by the collision energy, cause the open edge portion to tilt in a predetermined direction.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a vehicle body frontal structure which can be applied to a vehicle such as an automobile or the like.

Priority is claimed on Japanese Patent Application No. 2004-138322, filed May 7, 2004, the content of which is incorporated herein by reference.

2. Description of Related Art

In the past, in a vehicle body frontal structure for an automobile or the like, from the point of view of enhancing the collision absorption performance of the bumper, it has been per se known to provide an energy absorbing member which can absorb the energy of collision between the bumper face and the bumper beam. Among such energy absorbing members, one is per se known (for example, refer to Japanese Unexamined Patent Application, First Publication No. H11-342812) in which a separate member is joined as one unit to the bumper beam, and one which is formed as one unit with the bumper beam (for example, refer to Japanese Unexamined Patent Application, First Publication No. 2003-212069). Furthermore, among the latter type, there is a per se known one in which the bumper beam and the energy absorbing member are formed together as one unit using an extruded aluminum material or the like, and moreover, by making the energy absorbing member with a cross sectional shape of pantograph form, its energy absorption efficiency is enhanced, while minimizing the amount of incomplete collapse in the energy absorbing member.

With the above described prior art techniques, when questions of manufacturing efficiency and the like are considered, in practice the former is more usually employed. However, with the former, if an attempt is made to restore the pantograph shaped cross sectional shape to its original condition, this is difficult since its structure is rather complicated; and accordingly, from this type of point of view, there is a demand for a structure in which the amount of incomplete collapse in the energy absorbing member is minimized.

SUMMARY OF THE INVENTION

In view of the above circumstances, an object of the present invention is to provide a vehicle body frontal structure in which the amount of incomplete collapse in the energy absorbing member can be minimized with a simple configuration.

As a means for solving the above described problem, the present invention provides a vehicle body frontal structure including: a bumper face extending in a widthwise direction of a vehicle; a bumper beam disposed behind the bumper face and extending in the widthwise direction of the vehicle; and an energy absorbing member disposed between the bumper face and the bumper beam, formed in a hollow cross sectional shape of which a rear portion is left open, and having an open edge portion that is joined to the bumper beam, so as to deform and absorb collision energy when the collision energy in a rearwards direction of the vehicle is applied to the bumper face; wherein the open edge portion includes cutaway portions which leave portions of the open edge portion as joining leg portions to the bumper beam, and wherein the joining leg portions are provided with deformation guide portions which, in the initial period of deformation by the collision energy, cause the open edge portion to tilt in a predetermined direction.

The present invention provides a vehicle body frontal structure including: a bumper face extending in a widthwise direction of a vehicle; a bumper beam disposed behind the bumper face and extending in the widthwise direction of the vehicle; and an energy absorbing member disposed between the bumper face and the bumper beam, formed in a hollow cross sectional shape of which a rear portion is left open, and having an open edge portion that is joined to the bumper beam, so as to deform and absorb collision energy when the collision energy in a rearwards direction of the vehicle is applied to the bumper face; wherein the open edge portion includes joining leg portions that are joined to the bumper beam, and wherein the joining leg portions are provided with deformation guide portions which, in the initial period of deformation by the collision energy, cause the open edge portion to tilt in a predetermined direction.

According to the above structures, when, due to a collision, a body comes into violent contact with the bumper face, and collision energy is applied to the bumper face in the rearwards direction of the vehicle, and the energy is inputted to the energy absorbing member and starts to deform it, first, this deformation begins at the joining leg portions which are partially provided. At this time, due to the provision of the deformation guide portions, the open edge portion deforms so as to tilt towards a predetermined direction (for example, in cross section, towards the interior of the energy absorbing member), and thereby, as the subsequent deformation is induced, it becomes possible for the energy absorbing member to be collapsed smoothly, so that, as a result, the amount of incomplete collapse in the energy absorbing member can be minimized.

According to the structure of the present invention, since the amount of incomplete collapse in the energy absorbing member can be minimized, it becomes possible to take advantage of the space between the bumper face and the bumper beam, with no wastage of the deformation stroke of the energy absorbing member. In other words, it is possible to enhance the collision energy absorption efficiency of the vehicle body frontal portion. Furthermore, there is no influence upon the design of the bumper face or upon the component layout surrounding the bumper beam or the like, and it is possible to enhance the freedom of design of the vehicle body frontal portion. Moreover, by providing the cutaway portions, it is possible to anticipate a lightening of the energy absorbing member.

DETAILED DESCRIPTION OF THE INVENTION

In the following, a preferred embodiment of the present invention will be explained with reference to the drawings. It should be understood that, in this explanation, the orientations of front, rear, left, and right and so on are to be understood as being referred to the body of the vehicle, unless specifically stated otherwise. Furthermore, the arrow signs FR in the figure refers to the forward direction of the vehicle, while the arrow sign LH refers to the direction towards the left side of the vehicle and the arrow sign UP refers to the upward direction relative to the vehicle.

FIG. 1is a sectional view of the front end portion of a vehicle such as an automobile or the like taken in a central vertical plane extending along the longitudinal direction of the vehicle, and, as shown in this figure, a front bumper10of the vehicle includes a bumper face11and a bumper beam12, both of which extend in the widthwise direction of the vehicle. The bumper beam12is positioned in front of a radiator13for the engine of the vehicle and a condenser14for an air conditioning system of the vehicle and so on, and the bumper face11is provided so as to cover over the bumper beam12from the front.

The bumper beam12is, for example, made as a roughly rectangular steel tube arranged so that the long dimension of its cross sectional shape extends vertically, and this type of bumper beam12extends, just like a cross member15of the vehicle body, so as to straddle side frames (not shown in the figures) on the left and right sides of the body of the vehicle; and, moreover, both of its end portions are connected via connecting stays16(refer toFIGS. 2 and 3) to the side frames. By this arrangement, the bumper beam12also functions as a reinforcing member for the frontal portion of the vehicle body.

The bumper face11is made from a thermoplastic resin such as, for example, polypropylene or the like, and it constitutes one of the external surfaces of the vehicle which endow it with its characteristic appearance. A grille17is provided at a location somewhat below the central portion of the bumper face11in its vertical direction, for allowing air provided by the motion of the vehicle to be supplied to the radiator13and the condenser14, and, above and below the grille17, the cross sectional shape of the bumper face11is formed so as to be open to the rear.

At the region of the bumper face11above the grille17(in the following, termed the bumper upper portion18), the height of the bumper bottom wall portion18aand the height of the bottom wall portion12aof the bumper beam12are approximately equal to one another. Furthermore, the bumper beam12is provided so as to overlap with the lower half portion of the bumper upper portion18as seen in elevation from the front of the vehicle. In other words, the bumper beam12extends along the bumper upper portion18while being located as low as possible.

It should be understood that the reference symbol19in the figures denotes a strengthening frame which extends between a cross member15and an upper radiator support member (not shown in the drawings). If the bumper beam12is to shift to the rear, this strengthening frame19must allow this shifting, and accordingly the strengthening frame19is cranked towards the rearward direction at its upper portion which is at the same height as the bumper beam12, thus allowing space for such rearward shifting thereof. The bumper beam12is thus disposed at a roughly central position between this strengthening frame19and the bumper front wall portion18bof the bumper face11.

Moreover, a safety plate (an energy absorbing member)20is provided between the bumper beam12and the bumper face11, and, when the vehicle collides with some object which hits the bumper face11, this safety plate20deforms so as to receive the energy of the collision, and, by absorbing a part or all of this collision energy, mitigates the damage to the vehicle and to the object with which the vehicle has collided.

Referring toFIGS. 2 and 3together, this safety plate20has a hollow cross sectional shape of which the rear portion is open, and it is made by, for example, press forming a steel plate. This safety plate20includes a plate upper wall portion20cwhich is provided so as to slant downwards to the front, a plate bottom wall portion20awhich is provided so as to extend in a generally horizontal direction, and a plate front wall portion20bwhich is provided so as to extend in a generally vertical direction, and so as to extend between the front edges of the plate upper wall portion20cand the plate bottom wall portion20a.

Furthermore, the safety plate20is made so as to have a substantially V-shaped cross sectional shape, with the plate front wall portion20bwhich is provided at its generally lower half portion projecting to the front as a vertex portion. It should be understood that this plate front wall portion20bis disposed so as to be in the proximity of the bumper front wall portion of the bumper face11, and moreover is bulged out so as to be of a convex shape towards the front along the bumper front wall portion18b, as seen from the exterior of the vehicle.

To explain this matter with reference toFIG. 4as well, the plate upper wall portion20cof the safety plate20is curved so that, at its upper side rear edge portion (open edge portion)21, it becomes generally horizontal along its entire extent, and a plurality of upper edge joining portions23(at four spots, in the shown embodiment) which are provided at roughly equal intervals upon the upper side rear edge portion21are contacted against the frontal portion of the beam upper wall portion12cof the bumper beam12, so as to be borne thereupon.

In this state, each of the upper edge joining portions23is joined to the beam upper wall portion12cby being welded thereto.

The plate bottom wall portion20aof the safety plate20is provided so as to be at almost the same height as the beam bottom wall portion12aof the bumper beam12. At the lower side rear edge portion (the open edge portion)22of this plate bottom wall portion20a, there are provided a plurality of cutaway portions25(three in the shown embodiment), so as to leave portions thereof as joining leg portions24with the bumper beam12. In other words, there are provided a plurality of sites (four in the shown embodiment) on both sides of the cutaway portions25, which remain as the joining leg portions24. Due to these cutaway portions25, the rear edges (hereinafter termed the cutaway rear edges26) at the sites upon the plate bottom wall portion20aat which these joining leg portions24are not present are separated by a predetermined amount from the beam front wall portion12bof the bumper beam12.

Each of the rear end portions24aof these joining leg portions24is contacted from the underneath against the beam bottom wall portion12aof the bumper beam12, and, in this state, they are connected to the beam bottom wall portion12aby being welded thereto. It should be understood that support legs27are provided between both side portions of the plate front wall portion20bof the safety plate20and the beam front wall portion12bof the bumper beam12, so as to extend therebetween (refer toFIGS. 2 and 3).

Embossing processing is appropriately performed upon the plate upper wall portion20cand the bottom wall portion20aof the safety plate20, so as to extend generally along the longitudinal direction of the vehicle. Thus, between each of the two joining leg portions24at the inside in the vehicle widthwise direction of the plate bottom wall portion20aand the plate front wall portion20b, there is formed an internal reinforcing embossed portion28extending therebetween. In the same manner, between a site of the plate bottom wall portion20aneighboring to each of the two joining leg portions24towards the outside of the vehicle in its widthwise direction and the plate front wall portion20b, there is formed an external reinforcing embossed portion29extending therebetween. It should be understood that each of these reinforcing embossed portions28and29is formed by deforming the plate bottom wall portion20ain the upwards direction, as shown inFIG. 3.

At each of the joining leg portions24of the plate bottom wall portion20aof the safety plate20, there is provided a deformation guide portion30for causing the lower side rear edge portion22of the plate bottom wall portion20ato slant in the direction inward with respect to the cross section of the safety plate20, during the initial deformation when collision energy in the rearward direction has been applied to the bumper face11.

As shown inFIG. 5, each of these deformation guide portions30includes a front side curved portion31which is in a position which adjoins to the cutaway rear edge26above the plate bottom wall portion20aas seen from the side of the vehicle, a sloping wall32which extends from the rear thereof downward to the rear, and a rear side curved portion33which is located at the rear edge of the sloping wall32; and the rear end portion24aextends onward to the rear from the rear side curved portion33. In other words, the rear end portion24aof each of the joining leg portions24is joined to the bumper beam12, after the joining leg portion24has been deformed from the plate bottom wall portion20adownwards via the deformation guide portion30(or, to put it in another manner, in cross section, in the outward direction relative to the safety plate20).

Next, the manner in which the above described structure operates during a collision will be explained.

FIG. 6Ashows the situation for the joining leg portions24before the collision; and when, from this state, collision energy is applied to the bumper face11in the rearward direction, the bumper face11deforms and its bumper front wall portion18bcomes into contact with the plate front wall portion20bof the safety plate20, so that the energy (load) is inputted to the safety plate20via the bumper face11.

At this time, since the reaction force is concentrated upon the joining leg portions24which have been partially left between the cutaway portions25, deformation first starts to take place at these joining leg portions24.

Since, in each of the joining leg portions24, the deformation guide portion30is provided, in which the rear end portion24awhich is joined to the bumper beam12is bent in the downward direction, accordingly, when the load is inputted towards the rearward direction, as shown inFIG. 6B, the sloping wall32is deformed so as to swing in the upward direction around the rear side curved portion33as a center, and the front side curved portion31comes to shift in the upward direction, in other words, in cross section, towards the direction of the interior of the safety plate20.

Since the front side curved portion31is above the plate bottom wall portion20a, accordingly, by this front side curved portion31shifting in the upwards direction, the plate bottom wall portion20acomes to tilt, so as to shift the lower side rear edge portion22in the upwards direction about its front edge as a center. In other words, the plate bottom wall portion20ais deformed from the roughly horizontal state to a state in which its rear portion is raised.

FIG. 7Ashows the state at one of the cutaway portions25before the collision, and, in this state, the roughly horizontal plate bottom wall portion20ais positioned at roughly the same height as the beam bottom wall portion12aof the bumper beam12, and moreover the cutaway rear edge26is separated from the beam front wall portion12bof the bumper beam12.

When from the state described above collision energy in the rearwards direction is inputted to the safety plate20, then, as shown inFIG. 7B, due to the operation of the deformation guide portions30, the plate bottom wall portion20adeforms in the state of rising upwards and backwards until the point at which the cutaway rear edge26comes into contact with the beam front wall portion12bof the bumper beam12.

When the deformation of the safety plate20proceeds further from the state in which the cutaway rear edge26has come into contact with the beam front wall portion12bof the bumper beam12, the plate bottom wall portion20adoes not undergo buckling deformation in an irregular manner, but rather, as shown inFIG. 7C, the cutaway rear edge26slides towards the upwards direction along the surface of the beam front wall portion12bof the bumper beam12, and the entire body of the plate bottom wall portion20adeforms so as to be collapsed in the direction towards the interior of the safety plate20, in cross section. In this manner, the safety plate20collapses in a smooth manner.

Thus, the vehicle body frontal structure according to the above described preferred embodiment of the present invention is one in which, between the bumper face11and the bumper beam12which extend in the widthwise direction of the vehicle, there is provided the safety plate20which has a hollow cross sectional shape of which a rear portion is left open, and of which the rear edge portions21and22, which are open edge portions thereof, are joined to the bumper beam12, and which, when collision energy in the rearwards direction of the vehicle is applied to the bumper face11, absorbs the energy by deformation of the safety plate20; wherein, in the lower side rear edge portion22, there are provided the cutaway portions25which leave portions of the lower side rear edge portion22as the joining leg portions24to the bumper beam12, and, in the joining leg portions24, there are provided the deformation guide portions30which, in the initial period of deformation by the collision energy, cause the lower side rear edge portion22to tilt in a predetermined direction.

When due to a collision some object comes into contact with the bumper face11, so that collision energy in the rearward direction of the vehicle is applied to the bumper face11, and the energy is inputted to the safety plate20and starts to deform it, first, this deformation begins at the joining leg portions24which are left between the cutaway portions25. At this time, due to the provision of the deformation guide portions30, the lower side rear edge portion22deforms so as to tilt towards the interior direction of the safety plate20, in cross section, and, as the subsequent deformation is induced, it becomes possible for the safety plate20to be collapsed smoothly, so that, as a result, the amount of incomplete collapse in the safety plate20can be minimized.

In this manner, by minimizing the amount of incomplete collapse in the safety plate20, it becomes possible to take advantage of the space between the bumper face11and the bumper beam12, with no wastage of the deformation stroke of the safety plate20. In other words, it is possible to enhance the collision energy absorption efficiency of the vehicle body frontal portion. Furthermore, there is no influence upon the design of the bumper face11or upon the component layout surrounding the bumper beam12or the like, and it is possible to enhance the freedom of design of the vehicle body frontal portion.

Moreover, by providing the cutaway portions25, it is possible to anticipate a lightening of the safety plate20. Furthermore, by the deformation guide portions30being provided so that, in cross section, they are deformed in the direction towards the interior of the safety plate20, it becomes difficult for these deformation guide portions to become inverted, even when the safety plate20is manufactured by press forming. Although it is also possible to set the deformation guide portions30so that the plate bottom wall portion20aof the safety plate20is deformed in the outward direction, in cross section, it is preferable for the plate bottom wall portion20ato deform in the inward direction, in cross section, from the point of view of avoiding interference between the lower side rear edge portion22and the bumper face11.

It should be understood that the present invention is not to be considered as being limited to the embodiment disclosed above; for example, it would also be acceptable for the upper side rear edge portion21to be joined to the bumper beam21via joining leg portions as well. Furthermore, it would also be acceptable for the safety plate20to be made, as an energy absorbing member, from resin or the like, instead of being made from a pressed steel plate. Moreover, a structure would also be acceptable in which separate joining leg portions24were joined to the main body of the safety plate20.