Vehicle floor structure for a motor vehicle

A cross member passes a longitudinal member. The cross member is connected, on its outer end, to a side sill assembly and includes a connecting portion that divides the cross member into a remote cross member portion from the outer end of the cross member, and the other cross member portion. A reinforcement element extends through the connecting portion into the remote cross member portion and terminates in at its inner end spaced by a gap from a top wall of the longitudinal member, and it extends into the other cross member portion and terminates in at its outer end in the neighborhood of the side sill assembly. It is connected to an upper inner wall of the remote cross member portion, but spaced from an upper inner wall of the other cross member portion.

The present application claims the priority of Japanese Patent Application No. 2007-178399, filed Jul. 6, 2007, the disclosure of which is hereby incorporated by reference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a vehicle floor structure for a motor vehicle.

2. Background Art

JP-A 8-80874 (now JP Pat. No. 3381404) discloses a vehicle with a seat cross member, which is connected to a longitudinal floor beam, for example, a floor side sill assembly, on each side of the vehicle, and a center tunnel. Each of the seat cross members includes a recessed portion between an outer end side portion and an inner end side portion. The recessed portion and the outer end side portion are connected by a connecting portion. The connecting portion includes a ramp between top walls of the recessed portion and the outer end side portion. The top wall of the recessed portion is lower in height than the top wall of the outer end side portion.

An object of the present invention is to provide a vehicle floor structure with a seat cross member in a floor which is stable but which guarantees optimal deforming and/or bending properties to absorb the impact load in the event of a side collision.

SUMMARY OF THE INVENTION

According to one aspect of the present invention, there is provided a vehicle floor structure for a motor vehicle, comprising:

a side sill assembly on each side of the vehicle;

a longitudinal member;

a cross member passing, on a predetermined portion between outer and inner ends thereof, the longitudinal member and providing a gap above the longitudinal member, the cross member being connected, on an outer end thereof, to the side sill assembly,

the cross member including, between the longitudinal member and the side sill assembly, a connecting portion that divides the cross member into two cross member portions and connects the two cross member portions together, the two cross member portions including a remote cross member portion from the outer end of the cross member and the other cross member portion; and

a reinforcement element extending through the connecting portion into the remote cross member portion and terminating in at an inner end thereof spaced above from a top wall of the longitudinal member, the reinforcement element being connected to an upper inner wall of the remote cross member portion to reinforce same, the reinforcement element extending into the other cross member portion and terminating in at an outer end thereof in the neighborhood of the side sill assembly, the reinforcement element being spaced from an upper inner wall of the other cross member portion.

DETAILED DESCRIPTION OF THE INVENTION

Initially it is noted that the drawings referred to hereinafter as illustrating the preferred embodiment of the present invention are not to scale and are schematic in nature and, therefore, should not be taken too literally. Nevertheless, the drawings illustrate the invention sufficiently to enable one skilled in the art to practice the invention.

FIG. 2in conjunction withFIGS. 1 and 3shows a vehicle floor structure of a vehicle, of which only the center section in the region of two seat cross members9,9is shown. The vehicle floor structure comprises two longitudinal members7,7, a center tunnel3in a floor panel1and two side sill assemblies5,5. Only a portion of a right one of the two side sill assemblies5,5is shown inFIG. 2. A portion of a left one of the two side sill assemblies5,5is shown inFIG. 1. The center tunnel3protrudes toward a passenger compartment2and runs or extends along the vehicle longitudinal center axis L-L (seeFIG. 2). The center tunnel3holds the cross members9,9so that they function as a single cross member between the two side sill assemblies5,5.

Disposed on the floor panel1between the right side sill assembly5and the center tunnel3is a right longitudinal member7that extends generally along the vehicle longitudinal center axis L-L. Disposed on the floor panel1between the left side sill assembly5and the center tunnel3is a left longitudinal member7that extends generally along the vehicle longitudinal center axis L-L. In the embodiment, the longitudinal members7,7are rear extensions of two front side members, not shown, that extend rearwards from the front of the vehicle. Thus, the longitudinal members7,7may be called front side member rear extensions.

Each of the longitudinal members7,7has a top wall7a, two bent down side walls7b,7cfrom side edges of the top wall7a, and downwardly facing laterally bent flanges7d,7efrom bottom edges of the side walls7b,7c. The flanges7d,7eare fixedly connected to the floor panel1. In other words, each of the longitudinal members7,7has downwardly facing bent down legs7b,7d, and7c,7econnected to the floor panel1.

Interposing the center tunnel3, the two cross members9,9of right and left are connected to the floor panel1on the right and left sides of the center tunnel3. Stepping over the respective longitudinal members7,7, the cross members9,9extend in the vehicle width direction. In other words, crossing the respective longitudinal members7,7, the cross members9,9extend in the vehicle width direction.

As best seen inFIG. 3, the cross member9passes, on a predetermined portion between outer and inner ends thereof, the longitudinal member7. To avoid interference contact with the longitudinal member7, the predetermined portion of the cross member9is cut upwardly from below to form a tunnel opening9athat allows the passage of the longitudinal member7. The cross member9has two flanges9bextending along the vehicle longitudinal center axis L-L in the opposite directions from above the tunnel opening9a. InFIG. 3, only a front one9bof the flanges is shown, but a rear one of the flanges is not shown. The front and rear flanges9bare fixedly connected to a top wall7aof the longitudinal member7.

Each of the cross members9,9has a top wall9c, two bent down side walls9d,9efrom side edges of the top wall9c, and downwardly facing bent flanges9f,9g(seeFIG. 8) from bottom edges of the side walls9d,9e. The flanges9f,9gare fixedly connected to the floor panel1. In other words, each of the cross members9,9has downwardly facing bent down legs9d,9f, and9e,9gconnected to the floor panel1.

As shown inFIG. 1, at its outer end, each of the cross members9,9has a flange9hfixedly connected to a sill inner5aof one of the side sill assemblies5. At its inner end, each of the cross members9,9has a flange9i(seeFIG. 2) fixedly connected to one of side walls3aof the center tunnel3. The side walls3aslope downwards.

The top wall9cof each of cross member9is recessed at a predetermined area between the center tunnel3and the side sill assembly5to provide a recessed section9j. The recessed section9jof the top wall9cis a flat top wall section9j3. The flat top wall section9j3is lower in height than the two remaining sections of the top wall9cwhich are not recessed. An inner one of the two remaining sections of the top wall9cwhich are not recessed extends inwards from the inner end of the cross member9and connects into the recessed section9jof the top wall9cby way of an inner connecting portion9j1, and an outer one thereof extends inwards from the outer end of the cross member9and connects into the recessed section9jof the top wall9cby way of an outer connecting portion9j2. The inner connecting portion9j1includes a ramp between the top wall of the inner section of the top wall9cwhich is not recessed and the flat top wall section9j3of the recessed section9j. This ramp slopes downwards toward the flat top wall section9j3in a direction from the center tunnel3toward the side sill assembly5. The outer connecting portion9j2includes a ramp between the top wall of the outer section of the top wall9cwhich is not recessed and the flat top wall section9j3of the recessed section9j. This ramp slopes downwards toward the flat top wall section9j3in a direction from the side sill assembly5toward the center tunnel3. The inner connecting portion9j1is located between the longitudinal member7and the center tunnel3, and the outer connecting portion is located between the longitudinal member7and the side sill assembly5.

From the above description, it is noted that the cross member9includes, between the longitudinal member7and the side sill assembly5, the outer connecting portion9j2that divides the cross member9into two cross member portions (seeFIG. 3). The two cross member portions include the remote cross member portion32from the outer end of the cross member9connected to the side sill assembly5. This cross member portion32carries the top flat wall9j3of the recessed section9j. The two cross member portions include the other cross member portion34adjacent to the side sill assembly5. This cross member portion34carries the top wall9cof the outer one of those remaining sections which are not recessed. The outer connecting portion9j2connects the remote cross member portion32and the other cross member portion34together.

Forming each cross member9with the above-mentioned recessed section9jprovides increased space under the associated one of seats17(seeFIG. 2). Referring also toFIG. 3, the flat top wall section9j3of the remote cross member portion32is lower in height than the top wall of the other cross member portion34. Because the ramp36slopes downwards toward the flat top wall section9j3in the direction from the side sill assembly5toward the center tunnel3, the connecting portion9j2provides a transition in cross sectional profile between the different cross sectional profiles of the two cross member portions32and34.

Referring toFIG. 2, arranged behind, with respect to the vehicle longitudinal axis L-L, each cross member9is another cross member13. The associated seat17is installed via a seat slide mechanism15on the sections of the top wall9cwhich are not recessed of the cross member and a top wall of the cross member13.

Referring toFIGS. 1,3,4and5, each cross member9is reinforced by an internal reinforcement element19. The reinforcement element19, within each cross member9, extends through the connecting portion9j2into the remote cross member portion32and terminating in at its inner end19bspaced by a gap23from a top wall7aof the longitudinal member7. As best seen inFIG. 4, the reinforcement element19is connected, on its top wall19c, to an upper inner wall9mof the remote cross member portion32to reinforce same. The reinforcement element19extends into the other cross member portion34and terminating in at its outer end19ain the neighborhood of the side sill assembly5(seeFIG. 1). As best seen inFIG. 5, the reinforcement element19is spaced from an upper inner wall9nof the other cross member portion34to provide a gap21.

Turning back toFIG. 1, at that portion of the side sill assembly5which is connected by the cross member9, a center pillar (or a B-pillar)20extends upwardly from the side sill assembly5. The center pillar20includes a pillar inner20aand a pillar outer20b. At its lower end portion, the pillar inner20ais fixedly connected to a sill outer5bof the side sill assembly5. The cross member9and the center pillar20lie in the common transverse plane with respect to the longitudinal center axis L-L (seeFIG. 2) of the vehicle.

The reinforcement element19forms the gap21with the upper inner wall9nof the other cross member portion34of the cross member9in approximately half of its entire length on the side of the outer end19a, that is, the outer side of the connecting portion9j2. Thus, the reinforcement element19has its outer end19adisposed adjacent to the side sill assembly5and its top wall19cspaced from the upper inner wall9nof the cross member9on the side of its outer end19a.

The reinforcement element19forms a gap23(seeFIG. 1) with the top wall7aof the longitudinal member7on the side of the inner end19b, that is, the inner side of the connecting portion9j2. This means that the reinforcement element19has its inner end19bspaced by a gap23from the top wall7aof the longitudinal member7.

As is seen fromFIGS. 4 and 5, the reinforcement element19has a cross sectional profile of a vertically inversed U and includes bent down side walls19dand19efrom the top wall19c.

Thus, the reinforcement element19has its top wall19cfixedly connected to the upper inner wall9mon the opposite side of the flat top wall section9j3on the inner side near the longitudinal member7, that is, the inner side of the connecting portion9j2. This means that the top wall19cof the portion of the reinforcement element19on the side of the inner end19bis fixedly connected to the upper inner wall9mof the cross member9on the opposite side of the flat top wall9j3.

As shown inFIG. 6, a lower side impact load in the direction F1of the arrow is applied to the side sill assembly5adjacent to the bottom end of the center pillar20in the event of a side collision. Smashing the bottom end of the center pillar20and the side sill assembly5, the lower impact load F1acts on the cross member9and the reinforcement element19in their longitudinal direction. InFIG. 6, the illustration of the center pillar20and the sill outer5bis hereby omitted.

The cross member9is reinforced by the reinforcement element19to maintain the required setting level of strength. The cross member9and the reinforcement element19are spaced from each other to form the gap21on that portion which is disposed on the side of the side sill assembly5. Thus, the strength of that cross member portion34of the cross member9which is spaced from the reinforcement element19does not rise too much so that the cross member portion34is compressed and broken in the longitudinal direction efficiently to absorb the impact energy.

It is noted that the cross member9is stable enough, but has the cross member portion34which is compressed and broken in a longitudinal direction when the cross member9is stressed in the longitudinal direction by the lower side impact load F1to absorb the impact energy in the event of a side collision.

As shown inFIG. 7, an upper side impact load in the direction F2of the arrow is applied to the center pillar20at a portion above the side sill assembly5in the event of a side collision. The cross member9and the reinforcement element19are deformed and bent on that zone25where the cross member9and the reinforcement element19are fixedly connected to each other so that the portions of the cross member9and the reinforcement element19on the side of the side sill assembly5move upwardly, thereby to absorb the impact energy.

The above-mentioned deformation and bending continue until the gap23disappears, that is, the reinforcement element19contacts with the top wall7aof the longitudinal member7. After the deformation and bending, the inner end19bor its adjacent portion contacts with the top wall7ato suppress further deformation and bending, thus securing a space within the passenger compartment3in the event of a side collision.

It is noted that the cross member9and the reinforcement element19are bent and deformed on that portion where the reinforcement element19is fixedly connected to the cross member9in such a direction to allow an upward movement of the side sill assembly5until the inner end19bof the reinforcement element19contacts with the top wall7aof the longitudinal member7when the cross member9is stressed in a rotational direction by the upper impact load F2applied to the center pillar20above the side sill assembly5in the event of a side collision. Because further deformation and bending of the cross member9and the reinforcement element19end after the inner end19bof the reinforcement element19contacts with the top wall7aof the longitudinal member7, a shape-locking connection is created to secure a space within the passenger compartment2in the event of a side collision.

In the embodiment, the cross member9is located under the passenger compartment2as high as the longitudinal member7, which is a rear extension of a front side member, and the cross member9and the center pillar20lie in the common transverse plane with respect the vehicle longitudinal center axis L-L. Thus, a space within the passenger compartment2is secured in the event of a side collision where the upper impact load F2is applied to the center pillar20.

As shown inFIG. 8, in the event of a front end collision, an impact load F3is applied. In this case, the reinforcement element19is stiff enough to bear the load to restrain the deformation of the cross member9. This suppresses the movement of the seat17along the vehicle longitudinal axis L-L (seeFIG. 3) in the event of a front end collision.

While the preferred embodiment of the present invention has been described with particularly herein, it is considered apparent that the present invention is capable of numerous modifications, replacements, and substitutions of parts and, therefore, is not to be limited. Rather, the present invention is only to be defined by the claims appended hereto, including equivalents thereof.