JP3470645B2 - Body floor structure - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a floor structure of a vehicle body.

[0002]

2. Description of the Related Art As a conventional floor structure of a vehicle body, as disclosed in, for example, Japanese Unexamined Patent Publication No. 10-194162, a center pillar is provided to counteract a collision input acting through the center pillar at the time of a side collision. Of which the reinforcement is connected across the base of the vehicle and the skeleton member in the vehicle width direction of the floor, and as shown in JP-A-9-99870, the floor is extruded in the front-back direction into a closed cross-section structure with a lightweight metal material. A molded product is known.

[0003]

However, in any of the above-mentioned prior arts, since the structure is simply designed to improve the rigidity of the floor, it is heavy in weight and secures a living space for the passenger compartment in a side collision. When a collision input acts on the vehicle body floor via the center pillar, the lower end portion of the center pillar is moved in the vehicle width direction, and the vehicle body floor is deformed by a required crushing reaction force. It was difficult to adjust to an ideal deformation mode that can absorb collision energy well.

Therefore, the present invention uses a lightweight and simple structure without increasing the number of parts or the number of assembling steps.
An object of the present invention is to provide a floor structure of a vehicle body capable of deforming a floor in an ideal mode at the time of a side collision, securing a living space in a vehicle interior, and improving a collision energy absorption effect. Is.

[0005]

According to a first aspect of the present invention, there is provided a floor main portion extruded in the front-rear direction in a closed sectional structure, and a vehicle width direction connected to front and rear end portions of the floor main portion. in the floor of the vehicle body structure and a strength member, the floor main portion via the center pillar constituted by the floor center part side of a side collision input comprises a floor side portion and the floor tunnel portion acting, these Floor side part and frame
Areas of different strength, which are different in strength from the lower center side, are set by dividing them in the width direction of the vehicle.
Area is set to the floor side part, and the floor side part
The strength of the upper wall is set to be larger than that of the lower wall .

[0006]

According to a second aspect of the present invention, the high-strength regions according to the first aspect are set in the floorside portion and the floor center portion, and regions having lower strength than these are set in the floorside portion and the floor. The feature is that it is set in the middle part between the center part.

According to the invention of claim 3 , claim 1 or
The high-strength region described in 2 is characterized in that the floor constituting member having a closed cross section is made thicker than the low-strength region.

According to the invention of claim 4 , claim 1 or
The high-strength region described in 2 is configured such that the thickness of the floor constituting material of the closed cross section is thicker than that of the low-strength region, and the upper wall of the floor constituting material of the closed cross section has a lower thickness. It is characterized by being set thicker than the wall thickness.

According to the invention of claim 5 , claim 1 or
The high-strength region described in 2 is characterized in that the floor constituent material of the closed cross section is made of a high-strength material with respect to the low-strength region.

According to the invention of claim 6 , claim 1 or
The high-strength region described in 2 is characterized in that the closed cross-section height of the floor constituting material of the closed cross-section is made higher than that of the low-strength region.

According to the invention of claim 7 , claim 1 or
The high-strength region described in 2 is characterized in that a reinforcing rib wall is additionally provided in the closed cross-section of the floor constituting material of the closed cross-section with respect to the low-strength region.

According to the invention of claim 8 , claims 1 to 7 are provided.
Characterized in that the floor structural material of the closed cross section of the high-strength region and the floor structural material of the closed cross-section of the low-strength region are separately molded, and these are integrally connected by a connecting means. There is.

According to a ninth aspect of the present invention, the connecting means according to the eighth aspect is either a floor constituent member having a closed cross section in a high strength region or a floor constituent member having a closed cross section in a low strength region. One of the socket portions formed by opening one end in the vehicle width direction, and the other insertion portion formed at the end portion in the vehicle width direction of the other floor member having a closed cross section and fitted into the socket portion. The socket portion and the insertion portion are provided with engaging means for engaging with each other at the time of fitting.

[0015]

According to the invention described in claim 1, the floor main portion is extruded in the front-rear direction in a closed cross-section structure, and the strength members in the vehicle width direction are connected to both front and rear ends thereof. ,
Not only can the overall strength of the vehicle body floor be increased, but on the floor main part, different strength regions with different levels of strength are divided in the vehicle width direction between the floor side part and the floor center part. Therefore, in response to a collision input that acts through the center pillar during a side collision, crush deformation starts in the vehicle width direction from a low strength region and the vehicle width direction from the lower end side of the center pillar To facilitate the movement of the vehicle to the vehicle and to increase the degree of rise of the collision energy absorption characteristics in the initial stage of the collision to easily obtain the ideal deformation mode, and to secure the living space in the passenger compartment. And the improvement of the collision energy absorption effect can be realized.

In addition, since the number of parts and the number of assembling steps are not increased, the mode control is light and the mode control can be easily performed, which is advantageous in terms of cost.

Further , since the high-strength region is set in the floor side portion, it is possible to prevent the floor side portion from being crushed and deformed in the vehicle width direction at the initial stage at the time of a side collision, and the lower end portion of the center pillar is prevented. It is possible to promote the movement of the lower end portion of the center pillar in the vehicle width direction while maintaining the angle of connection with the floor side portion, and it is possible to more advantageously secure the living space in the vehicle compartment.

According to the invention of claim 2 , claim 1
In addition to the effect of the invention described above, a high-strength region is set in the floor side part and the floor center part, and a low-strength region is set between them, so that the floor is not damaged at the initial stage of a side collision. The side portion can be prevented from being crushed and deformed in the vehicle width direction, and the movement of the lower end portion of the center pillar in the vehicle width direction can be promoted while maintaining the coupling angle between the lower end portion of the center pillar and the floor side portion. Therefore, the living space of the vehicle compartment can be secured more advantageously.

Further, as described above, since the high-strength regions extend in the front-rear direction in the floor side portions on both sides and the floor center portion, the strength and rigidity in the front-rear direction of the floor can be remarkably enhanced.

According to the invention described in claim 3, claim 1
Alternatively , in addition to the effect of the second aspect of the invention, the different strength region of the floor main portion can be easily set by sectioning by adjusting the plate pressure of the floor component.

According to the invention of claim 4 , claim 1
Alternatively , in addition to the effects of the invention of 2 , the different strength regions of the floor main portion can be easily set by adjusting the plate pressure of the floor component, and the plate thickness of the upper wall of the floor component of the closed cross section can be reduced. Since it is set thicker than the wall thickness of the wall, particularly in the floor side portion, it is possible to enhance the effect of holding the joint angle between the lower end portion of the center pillar and the floor side portion at the time of a side collision.

According to the invention of claim 5 , claim 1
Alternatively , in addition to the effect of the second aspect of the invention, the different strength region of the floor main portion can be easily set by classification by selecting the material of the floor constituent material.

According to the invention of claim 6 , claim 1
Alternatively , in addition to the effect of the second aspect of the invention, it is possible to easily set the different strength regions of the floor main portion by adjusting the height of the closed cross section of the floor component.

According to the invention described in claim 7, claim 1
Alternatively , in addition to the effect of the second aspect of the invention, the different strength region of the floor main portion can be easily set by section by adjusting the set number of the reinforcing rib walls of the closed cross section of the floor component.

According to the invention described in claim 8 , claim 1
In addition to the effects of the inventions of to 7 above , a plurality of floor constituent materials are separately molded, and both of them are integrally connected by a connecting means to set the different strength regions, which is advantageous in manufacturing. The floor main part can be configured.

According to the invention of claim 9 , claim 8
In addition to the effect of the invention described above, since a plurality of floor constituent members can be firmly joined by a so-called one-touch operation of merely fitting the socket portion and the insertion portion, the assembling work can be easily performed.

[0027]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIGS. 1 and 2, reference numeral 1 denotes a vehicle body floor, which is a floor main portion 2 extruded in the front-rear direction by a lightweight metal material such as an aluminum alloy in a closed cross-section structure, and a closed cross-section structure made of the same material. Extruded into the floor main part 2
The front and rear ends of the vehicle are provided with strength members 7, 7 in the vehicle width direction joined by welding or bolts and nuts.

The floor main portion 2 has a closed cross-section structure composed of an upper wall 3, a lower wall 4, and a plurality of longitudinal reinforcing rib walls 5 connecting the upper and lower walls 3, 4.

Front and rear skeleton portions 6 having a closed cross section which constitute side sill inners are integrally formed at both ends of the floor main portion 2 in the vehicle width direction.
The body side assembly 11 formed separately from the vehicle body floor 1 is connected.

The body side assembly 11 is constructed by integrally molding a side sill outer 12, a front pillar 13, a center pillar 14 and a roof side rail 15, and the side sill outer 12 is attached to a side sill inner 6 (a skeleton portion in the front-rear direction). They are combined and assembled to the vehicle body floor 1.

Here, the floor main portion 2 has a different strength region in which a difference in strength is given, that is, a high strength region S1.
And a region S2 having a lower strength than this are divided and set in the vehicle width direction.

In this embodiment, an area S1 of high strength on the side of the floor side of the general floor portion 2B extending substantially horizontally on both sides of the floor tunnel portion 2A with the reinforcing rib wall 5 at the substantially central portion in the vehicle width direction as a boundary. Then, the floor center portion side including the floor tunnel portion 2A is set as a region S2 having lower strength.

The difference in intensity between these regions S1 and S2 is
For example, the area S1 having a high strength can be arbitrarily set by forming the floor constituent material having a closed cross section with a larger plate thickness than the area S2 having a low strength.

Although it is possible to integrally extrude the regions S1 and S2 by changing the plate thickness, as shown in FIG. 3, the floor constituent materials of the regions S1 and S2 are extruded separately, Both may be integrally connected by the connecting means 21.

In the embodiment shown in FIG. 3, the connection means 21
As a result, the closed cross section of the vehicle width direction end of the floor component in the low strength region S2 is opened to form the socket portion 22, while the closed cross section of the vehicle width direction end of the floor component in the high strength region S1 is formed. The insertion part 2 having a slightly smaller outer shape than the socket part 22 so that the socket part 22 can be fitted into the socket part 22.
3 to form the socket portion 22 and the insertion portion 2
3 and 3 are fitted and connected.

Further, the socket portion 22 and the insertion portion 2
The engaging hooks 3 are engaged with each other at the time of fitting, for example, locking hooks 2 provided on the upper and lower inner sides of the open end of the socket 22.
4 and hook engaging grooves 25 provided on the upper and lower walls of the insertion portion 23
When the socket portion 22 and the insertion portion 23 are fitted with each other, the engaging hook 24 and the hook engaging groove 25 can be firmly coupled to each other.

Next, the operation of the first embodiment having the above structure will be described.

When a collision input F acts on the center pillar 14 as shown in FIG. 4 during a side collision of the vehicle, the collision input F is applied to the vehicle body floor 1 side and the roof 8 side collision input F ₁ , respectively. It is dispersed at the F _2.

In the vehicle body floor 1 and the roof 8, the roof 8
Since the reaction force when the vehicle body floor 1 is crushed and deformed in the vehicle width direction is large as compared with the above, it is desirable to absorb the collision energy by crushing the vehicle body floor 1.

In addition to the collapse and deformation of the vehicle body floor 1 in the vehicle width direction during a side collision as described above, the center pillar 14 is centered at the connection point with the roof 8 at its upper end as shown by the broken line in FIG. As described above, it is the most ideal deformation mode that the lower end portion is deformed so as to rotate toward the passenger compartment side in order to secure a living space in the passenger compartment.

Here, as described above, the collision input to the center pillar 14 at the time of a side collision is F, and the center pillar 1
4 is the input from the vehicle floor 1 to F ₁ , the input from the center pillar 14 to the roof 8 is F ₂ , the span between the working points of F and F ₁ is L ₁ , and the span between the working points of F and F ₂ is To L
When _{2, F = F 1 + F} 2 ... (1) F 1 = F × L 2 / (L 1 + L 2) ... (2) F 2 = F × L 1 / (L 1 + L 2) ... (3) It can be assumed that the relational expression is established and the relationship between F ₁ and F ₂ is constant at each stage of a side collision.

On the other hand, as described above, in order to realize the ideal deformation mode at the time of a side collision, if the reaction force at which the roof 8 starts to be crushed is F _2max , the roof can be obtained from the equations (1) to (3). It is possible to define the upper limit value F _1max of the crushing reaction force of the vehicle body floor 1 that does not _{crush 8} .

In order to maintain such an ideal deformation mode and efficiently absorb the collision energy, that is, the vehicle body floor 1 has a smaller deformation amount (deformation stroke in the vehicle width direction). In order to absorb the above, it can be said that it is desirable to stably maintain the crushing reaction force of the vehicle body floor 1 as high as possible within a range not _{exceeding the} upper limit value F _1max .

When the floor main portion 2 of the vehicle body floor 1 is formed by extrusion molding in the front-rear direction in a closed cross-section structure as described above, the center pillar 14 is provided in the first half of the side collision as illustrated in FIG. Although it deforms only in the vicinity of the root of the vehicle, the deformation section spreads in the front-rear direction of the vehicle body as the deformation progresses in the latter half, and when viewed from above the vehicle body, it becomes a deformation mode in which ripples spread as shown by the broken line in FIG. When the strength of the floor main portion 2 is constant in the vehicle width direction, the crushing reaction force of the vehicle body floor 1 as shown by the line C in FIG.
As the deformation of No. 1 increases, the deformation stroke of the vehicle body floor 1 in the vehicle width direction also increases, and it is not possible to efficiently absorb the collision energy while maintaining the preferable deformation mode as described above.

On the other hand, according to the structure of the first embodiment of the present invention, the floor main portion 2 is extruded in the front-rear direction in a closed cross-section structure, and the strength members 7 in the vehicle width direction are provided at both front and rear ends thereof. Since they are connected, the overall strength of the vehicle body floor 1 can be increased, and the floor main portion 2 has a difference in strength between the floor side portion side and the floor center portion side. Since the strength region, that is, the high strength region S1 and the low strength region S2 are set separately in the vehicle width direction, the crushing deformation in the vehicle width direction starting from the low strength region S2 at the time of a side collision. By center pillar 1
Prompt movement in the vehicle width direction from the lower end side of 4, that is,
It is possible to promote rotational movement of the lower end of the center pillar 14 toward the vehicle compartment around the connection point of the upper end of the center pillar 14 with the roof 8.

Further, by the division setting of the high-strength region S1 and the low-strength region S2, the line a in FIG. 13 can be used within a range not _exceeding the required upper limit value F _1max of the crushing reaction force of the vehicle body floor 1 described above. It is possible to set the rising degree of the reaction force characteristic at the initial stage of the collision to be large and to set the crushing reaction force to be stable and as high as possible near the upper limit value F _1max as shown in (4). In addition to the ideal collision energy absorption characteristic, the mode control can be easily performed so that the deformation mode can be obtained, the living space of the vehicle interior can be secured, the deformation stroke of the vehicle body floor 1 is small, and the collision energy absorption amount is large. Obtainable.

In particular, in this embodiment, since the above-described high-strength region S1 is set in the floor side portion, it is possible to prevent the floor side portion from being crushed and deformed in the vehicle width direction at the initial stage of the side collision. Since the movement of the lower end of the center pillar 14 toward the vehicle interior can be promoted while maintaining the coupling angle between the lower end of the center pillar 14 and the floor side portion, the living space of the vehicle interior can be more effectively secured. can do.

In addition to the effect of absorbing the collision energy as described above, the different strength regions S1 and S2 of the floor main portion 2 are adjusted by adjusting the plate thickness of the floor constituting material having the above-mentioned closed cross section structure.
Since the setting is made, it can be advantageously constructed in manufacturing.

Further, since the different strength regions S1 and S2 are extruded separately, the molding can be performed more easily, and by fitting the socket portion 22 and the insertion portion 23, the locking hook 24 and the hook. The engaging groove 25 can be engaged and firmly coupled, and both can be connected with one touch, so that the assembling work can be easily performed.

Here, when a collision load is applied from the center pillar 14 to the vehicle body floor 1 in the above-mentioned side collision, an upward bending moment acts on the floor side portion around the input point of the center pillar 14. .

Therefore, in the case where the high-strength region S1 of the floor side portion is formed by increasing the thickness of the floor constituting material as described above, the lower wall 4 of the floor constituting material of the region S1 is raised. When the plate thickness is thicker than the wall 3, the lower wall 4 is bulged by the bending moment as shown in FIG. 6B, but the upper wall 3 is crushed and deformed, and the floor side portion and the center pillar lower end portion. It may not be possible to maintain the angle of connection with the center pillar 14, and the center pillar 14 may be bent near the base of the lower end thereof to make it difficult to axially collapse the vehicle body floor 1 in the vehicle width direction.

On the contrary, the upper wall 3 of the floor constituting material of the region S1
Is thicker than the lower wall 4, the crush deformation of the upper wall 3 and the lower wall 4 is started at substantially the same time with respect to the bending moment, and the crush deformation of the vehicle body floor 1 in the vehicle width direction is axially crushed. It becomes possible to approach.

Therefore, when the high-strength region S1 of the floor side portion is formed by increasing the thickness of the floor constituent material as described above, the thickness of the upper wall 3 of the floor constituent material is set to the lower wall 4.
It is desirable to set the thickness to be thicker than the plate thickness of the vehicle body 1 so that the vehicle body floor 1 can be efficiently collapsed and deformed in the vehicle width direction at the time of a side collision.

In the above embodiment, the different strength regions S1 and S2 of the floor main portion 2 are divided and set by changing the plate thickness of the floor constituting material. However, in addition to this, the material of the floor constituting material is changed. Can also be configured by
The floor constituent material in the high-strength area S1 is changed to the low-strength area S1.
By using a high-strength material for the second floor constituent material, it is possible to easily set different strength areas in this case. In this case, for example, as shown in FIG.
It is also possible to make the plate thicknesses of the floor constituent materials of 1 and the area S2 the same.

FIG. 8 shows a third embodiment of the present invention. In this embodiment, the high strength region S1 of the floor side portion is closed with respect to the low strength region S2 of the floor component. The closed cross-sectional area is enlarged by increasing the cross-sectional height and gradually raising the upper wall 3 toward the side sill inner 6 to form an oblique shape as shown in the figure.

Therefore, even in the case of the third embodiment, the same collision energy absorption effect as that of the first embodiment can be obtained, and the floor main portion 2 is adjusted by adjusting the height of the closed cross section of the floor component. The different intensity areas S1 and S2 can be easily set by classification.

9 and 10 show the fourth and fifth embodiments of the present invention. In both cases, the different strength regions S1 and S2 are formed by adjusting the set number of the reinforcing rib walls 5 within the closed section of the floor component. In the embodiment shown in FIG. 9, the floor components of the floor side portion are arranged horizontally across the reinforcing rib wall 5 and the side sill inner 6 in the center of the floor general portion 2B in the vehicle width direction. Direction reinforcing rib wall 5A is additionally provided, and in the embodiment of FIG. 10, the middle between the longitudinal reinforcing rib wall 5 and the side sill inner 6 in the vehicle width direction center of the floor general portion 2B. A reinforcing rib wall 5 in the vertical direction is further added to the section, and in each case, the side of the floor side is a high-strength region S1.

Therefore, even in the case of these fourth and fifth embodiments, it is possible to obtain the same collision energy absorbing effect as in the first embodiment, and at the same time, the reinforcing rib wall 5 in the closed cross section of the floor component. , 5A, the different strength regions S1 and S2 of the floor main portion 2 can be easily divided and set.

The sixth embodiment shown in FIG. 11 is a combination of the third embodiment shown in FIG. 8 and the fourth embodiment shown in FIG. 9. In the sixth embodiment, the floor of the floor side portion is By arranging the reinforcing wall 26 in a slanted manner so as to straddle the upper wall 3 and the side sill inner 6 of the constituent material, the height of the closed cross section is increased, and a part of the upper wall 4 is reinforced laterally by the reinforcing rib wall 5A. And functions as a region S1 having a high strength.

In the present embodiment, the reinforcing wall 26 is formed separately, and the region S1 is constituted by the simple means for joining and arranging the reinforcing wall 26 as described above. However, the reinforcing wall 26 may of course be integrally co-extruded. Good.

FIG. 12 shows a seventh embodiment of the present invention. In this embodiment, similarly to the first embodiment, the different strength regions S1 and S2 are separately set by adjusting the plate thickness of the floor constituting material. However, the side sill inner 6 and the floor side portion near the side sill inner 6 and the floor center portion around the floor tunnel portion 2A are connected to the high strength region S1 (OUT),
S1 (IN) is set, and an intermediate portion between the floor side portion and the floor center portion is set as a low strength region S2.

Therefore, also in the case of the seventh embodiment, substantially the same collision energy absorption effect as in the first embodiment can be obtained, but the region S2 of low strength is the region of high strength in each of the floor side portion and the floor center portion. S1 (OUT), S1
Since it is sandwiched by (IN), the degree of progress of the crushing deformation of the low-strength region S2 at the time of a side collision becomes large. Therefore, as shown by the line b in FIG. Compared with the first embodiment, the deformation stroke of the vehicle body floor 1 becomes slightly larger and the amount of collision energy absorption can be made substantially equal to that of the first embodiment.

In the seventh embodiment, the high-strength area S1 (OUT) of the floor side portion is made thicker in addition to having a thicker cross-sectional area as shown in FIG. Although the reinforcing rib wall 5B is added in a shape like this, it goes without saying that the plate thickness may simply be increased depending on the intended deformation mode.

Even in each of the embodiments shown in FIGS. 7 to 12, the different strength regions S1 and S2 are extruded separately,
Connection may be made by the same means as in FIG.

[Brief description of drawings]

FIG. 1 is an exploded perspective view schematically showing an overall outline of a first embodiment of the present invention.

FIG. 2 is a sectional view taken along the line AA of FIG.

FIG. 3 is a cross-sectional view showing a connection structure of different strength regions.

FIG. 4 is a schematic diagram illustrating a deformation mode in a side collision.

FIG. 5 is a schematic diagram illustrating a progression mode of crushing deformation at the time of a side collision.

FIG. 6 is a schematic diagram illustrating a deformation mode of a floor side portion in the case of a side collision.

FIG. 7 is a sectional view similar to FIG. 2, showing a second embodiment of the present invention.

FIG. 8 is a sectional view similar to FIG. 2, showing a third embodiment of the present invention.

FIG. 9 is a sectional view similar to FIG. 2, showing a fourth embodiment of the present invention.

FIG. 10 is a sectional view similar to FIG. 2, showing a fifth embodiment of the present invention.

FIG. 11 is a sectional view similar to FIG. 2, showing a sixth embodiment of the present invention.

FIG. 12 is a sectional view similar to FIG. 2, showing a seventh embodiment of the present invention.

FIG. 13 is a collision energy absorption characteristic diagram of the vehicle body floor during a side collision.

[Explanation of symbols]

1 Body floor 2 floor main part 3 Upper wall 4 lower wall 5,5A, 5B Reinforcing rib wall 7 Car width direction strength member 14 Center pillar S1 High strength area S2 Low intensity area 21 Connection means 22 Socket 23 Insert 24 Locking hook (locking means) 25 Hook engagement groove (locking means)

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-8-175419 (JP, A) JP-A-4-221279 (JP, A) JP-A-9-323669 (JP, A) JP-A-9- 99870 (JP, A) JP-A-4-334669 (JP, A) Actual development 3-84286 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) B62D 25/20 B62D 25 / 04

Claims (9)

(57) [Claims] 1. A floor structure of a vehicle body comprising a floor main part extruded in a front-rear direction in a closed cross-section structure and a strength member in the vehicle width direction connected to front and rear end parts of the floor main part, floor main portion, floor side portion and the floor tunnel portion which acts side collision inputted via the center pillar
Constituted by the floor center part side including the, these Furoasa
In addition to setting different strength regions that have height differences between the id part side and floor center part side in the vehicle width direction ,
Set a high-strength area on the floor side, and
The strength of the upper wall of the lower side is greater than the strength of the lower wall.
The floor structure of the vehicle body is characterized by the fact that it has been set . 2. A high-strength region is set in a floor side part and a floor center part, and a lower-strength region is set in an intermediate portion between the floor side part and the floor center part. The floor structure for a vehicle body according to claim 1. Areas of high wherein intensity, the floor of the vehicle body according to claim 1 or 2, characterized in that it is constituted by thickening the thickness of the closed section of the floor construction material with lower strength region Construction. 4. The high-strength region is formed by increasing the plate thickness of the floor component having a closed cross section as compared with the low-strength region, and the plate thickness of the upper wall of the floor component having the closed cross section is larger than that of the low-strength region. The floor structure for a vehicle body according to claim 1 or 2 , wherein the thickness is set thicker than the thickness of the lower wall. Areas of high 5. strength, relative low intensity regions of the vehicle body according to claim 1 or 2, characterized in that to constitute a floor construction material closed section using a high strength material Floor Construction. Areas of high 6. strength, relative low intensity regions, the vehicle body according to claim 1 or 2, characterized by being configured to increase a closed cross section height of the floor structure material closed cross section Floor structure. 7. A high strength region, with respect to low intensity regions, to claim 1 or 2, characterized in that configured by adding a reinforcing rib wall closed plane of the floor construction material closed cross section Floor structure of the car body described. 8. A floor structural material having a closed cross section in a high strength region and a floor structural material having a closed cross section in a low strength region are separately molded, and both are integrally connected by a connecting means. the floor of the vehicle body structure according to any one of claims 1 to 7, characterized. 9. The connecting means is formed by opening one end of the floor constituent member having a closed cross section in a high strength region and the floor constituent member having a closed cross section in a low strength region in the vehicle width direction. The socket portion and the insertion portion that is formed at the end portion of the floor component of the other closed cross section in the vehicle width direction and is fitted to the socket portion. The floor structure for a vehicle body according to claim 8 , further comprising engaging means for engaging with the floor.