WO2019176792A1

WO2019176792A1 - Floor structure

Info

Publication number: WO2019176792A1
Application number: PCT/JP2019/009420
Authority: WO
Inventors: 豊三日月; 中田　匡浩; 栄志磯貝
Original assignee: 日本製鉄株式会社
Priority date: 2018-03-13
Filing date: 2019-03-08
Publication date: 2019-09-19
Also published as: JPWO2019176792A1; JP6958722B2

Abstract

The present invention provides a floor structure that is provided with: a side sill that has a hat-shaped side sill outer and a hat-shaped side sill inner; a floor panel that is joined to the side sill inner; and a reinforcement member that is disposed at an inner side of the side sill inner, wherein the side sill outer and the side sill inner are joined at flange sections thereof; an angle θ formed by a top-surface section and a vertical-wall section of the side sill inner is 85 to 95 degrees; the floor panel is joined to an upper vertical-wall section or a lower vertical-wall section of the side sill inner; an upper end section of the reinforcement member is joined to the upper vertical-wall section, and a lower end section of the reinforcement member is joined to the lower vertical-wall section; and the value of W₁/t, which is the ratio of the width W₁ of the vertical-wall section of the side sill inner to the plate thickness t of the vertical-wall section thereof, is less than 42.9.

Description

Floor structure

The present invention relates to an automobile floor structure.

The floor structure of an automobile includes, for example, a floor panel, a side sill, a floor cross member, and other reinforcing members. In such a floor structure, for example, at the time of a side collision of an automobile, in particular, at the time of a pole side collision, a shock is absorbed mainly by bending deformation of the side sill and crushing deformation of the floor cross member, thereby securing a living space for the occupant. Yes. At this time, the floor panel is required not to be greatly deformed in order to secure the occupant's living space and to support the load from the side sill.

In recent years, a vehicle body layout in which a large-capacity battery is mounted under the floor panel has been adopted for the purpose of increasing the cruising range of an electric vehicle. In the vehicle body having such a layout, it is desired that the impact is surely absorbed by the deformation of the side sill so as not to damage the battery from the viewpoint of electrical safety at the time of a pole side collision. Therefore, it is necessary to enhance the load bearing performance when the side sill is deformed, and the floor panel is required to withstand the high load transmitted from the side sill so that the floor panel does not deform greatly. Note that a member such as a floor panel is greatly deformed so that a load input to the member is smaller than that before the large deformation. However, in this specification, the maximum input load before the member is largely deformed is referred to as “proof strength”.

On the other hand, in an electric vehicle, a driving component called a propeller shaft and an exhaust pipe are not required compared to a conventional vehicle. Therefore, a step shape called a tunnel provided at the center of the floor panel in the vehicle width direction is not required, and the floor panel can be formed into a substantially flat shape. From the viewpoint of processing such as press molding, a substantially flat floor panel can be easily provided with a shape such as emboss as compared with a conventional floor panel.

There is a conventional floor structure described in Patent Document 1. Patent Document 1 discloses a structure in which a reinforcing member is joined to the lower surface of the center portion in the vehicle width direction of the front portion of the cab floor as a cab over type cab floor reinforcing structure. The floor structure of Patent Document 1 is joined in a state in which the flange portion at the end in the vehicle width direction of the reinforcing member is in contact with the underframes disposed on the left and right of the reinforcing member.

JP 2000-135990 A

The floor structure is required to have improved yield strength. However, in the floor structure disclosed in Patent Document 1, a load is locally input to the flange portion at the end of the reinforcing member in the vehicle width direction at the time of a side collision, and the local portion Since the load is transmitted to the cab floor through the load, the load transmission efficiency is low.

As a conventional floor structure, for example, there is a floor structure 101 having a floor panel 102 and a side sill 103 as shown in FIG. FIG. 1 is a view showing a cross section perpendicular to the vehicle length direction L. The side sill 103 includes a hat-shaped side sill outer 104 and a hat-shaped side sill inner 105. A flange portion 102 a is formed at an end portion of the floor panel 102 in the vehicle width direction W (hereinafter referred to as “width direction end portion”), and the flange portion 102 a is joined to the top surface portion 105 a of the side sill inner 105. In the case of such a floor structure 101, for example, when the pole collides with the side sill outer 104 in the pole side collision test, as shown in FIG. Out-of-plane deformation occurs in such a manner that the wall portion “) and the lower vertical wall portion 105c (hereinafter referred to as“ lower vertical wall portion ”) in the vehicle height direction H open to the outside of the cross section. When the load is transmitted to the floor panel 102 while being deformed out of plane in this way, not only the load transmission efficiency is lowered, but the out-of-plane deformation of the floor panel 102 is induced and the proof stress cannot be sufficiently improved.

Further, as a conventional floor structure, for example, there is a floor structure 101 having a floor panel 102 and a side sill 103 as shown in FIG. FIG. 3 is a view showing a cross section perpendicular to the vehicle length direction L, and the side sill 103 includes a hat-shaped side sill outer 104 and a hat-shaped side sill inner 105. The width direction end portion of the floor panel 102 is joined to the lower vertical wall portion 105 c of the side sill inner 105. In the case of such a floor structure 101, for example, when the pole collides with the side sill outer 104 in the pole side collision test, the upper vertical wall portion 105b and the lower vertical wall portion 105c of the side sill inner 105 are outside the cross section as shown in FIG. When it opens, the out-of-plane deformation occurs. When the load is transmitted to the floor panel 102 while being deformed out of plane in this way, not only the load transmission efficiency is lowered, but the out-of-plane deformation of the floor panel 102 is induced and the proof stress cannot be sufficiently improved.

The present invention has been made in view of such a problem of the prior art, and an object thereof is to provide a floor structure with improved proof stress.

In order to solve the above-mentioned problems, the inventor has intensively studied the side sill and floor panel mounting structure for transmitting a load from the side sill to the floor panel with in-plane force, and the cross-sectional deformation behavior of the side sill at the time of pole side collision. The present invention has been completed with knowledge. That is, the inventor joins the floor panel to the upper vertical wall portion or the lower vertical wall portion of the hat-shaped side sill inner, and the reinforcing member that suppresses the out-of-plane deformation of the upper vertical wall portion and the lower vertical wall portion. It has been found that the above problem can be solved by defining a value of W ₁ / t, which is a ratio between the width W ₁ of the vertical wall portion of the side sill inner and the plate thickness t of the vertical wall portion.

Therefore, one aspect of the present invention that solves the above problems is a floor structure, a side sill having a side sill outer and a side sill inner, a floor panel joined to the side sill inner, and an inner side of the side sill inner The side sill outer has a hat-shaped cross section perpendicular to the vehicle length direction, and a vertical wall portion extending from the top surface portion to the vehicle inner side in the vehicle width direction. And a flange portion extending in the vehicle height direction, and the side sill inner has a hat-shaped cross section perpendicular to the vehicle length direction, and extends from the top surface portion to the vehicle outer side in the vehicle width direction. The side sill outer and the side sill inner are joined to each other by the flange part, and the side sill inner is provided. An angle θ formed by the top surface portion and the vertical wall portion of the side sill inner is 85 to 95 degrees, and the floor panel is an upper vertical wall portion that is the vertical wall portion on the upper side in the vehicle height direction of the side sill inner. Or, the reinforcing member is joined to the lower vertical wall portion which is the vertical wall portion on the vehicle height direction lower side of the side sill inner, the upper end portion of the reinforcing member is joined to the upper vertical wall portion of the side sill inner, and the lower end The portion is joined to the lower vertical wall portion of the side sill inner, and the value of W ₁ / t, which is the ratio of the width W _{1 of the} vertical wall portion of the side sill inner and the thickness t of the vertical wall portion, is It is characterized by being less than 42.9.

Another aspect of the present invention according to another aspect is a floor structure having a side sill outer and a side sill inner, a floor panel joined to the side sill inner, the side sill outer, and the side sill inner. The side sill outer has a hat-shaped cross section perpendicular to the vehicle length direction, and a vertical surface extending from the top surface portion to the vehicle inner side in the vehicle width direction. The side sill inner has a hat-shaped cross section perpendicular to the vehicle length direction, and includes a top surface portion and a vehicle in the vehicle width direction from the top surface portion. And an angle θ formed by the top surface portion of the side sill inner and the vertical wall portion of the side sill inner is 85 to 9 and has a vertical wall portion extending outward and a flange portion extending in the vehicle height direction. The floor panel is an upper vertical wall portion that is the vertical wall portion on the vehicle height direction upper side of the side sill inner, or a lower side that is the vertical wall portion on the lower side of the side sill inner in the vehicle height direction. The flange portion of the side sill outer, the reinforcing member, and the flange portion of the side sill inner are joined to each other, the width W _{1 of the} vertical wall portion of the side sill inner, The value of W ₁ / t, which is a ratio to the wall thickness t, is less than 35.7.

According to the present invention, a floor structure with improved proof stress can be provided.

It is a figure which shows the cross section perpendicular | vertical to the vehicle length direction of the conventional floor structure. It is a figure which shows the deformation | transformation state after the pole collision in the floor structure of FIG. It is a figure which shows the cross section perpendicular | vertical to the vehicle length direction of the conventional floor structure. It is a figure which shows the deformation | transformation state after the pole collision in the floor structure of FIG. It is a figure which shows the cross section perpendicular | vertical to the vehicle length direction of the floor structure concerning 1st Embodiment of this invention. It is a figure which shows the deformation | transformation state after the pole collision in the floor structure concerning 1st Embodiment of this invention. It is a figure which shows the cross section perpendicular | vertical to the vehicle length direction of the floor structure concerning 2nd Embodiment of this invention. It is a figure which shows the cross section perpendicular | vertical to the vehicle length direction of the floor structure concerning 3rd Embodiment of this invention. It is a perspective view which shows schematic structure of the floor structure which concerns on 4th Embodiment of this invention. It is a top view which shows schematic structure of the floor structure which concerns on 4th Embodiment of this invention. It is AA sectional drawing of FIG. FIG. 11 is a sectional view taken along line BB in FIG. 10. FIG. 11 is a view corresponding to the AA cross-sectional view of FIG. 10 showing an example of the shape of the floor panel. It is a figure which shows the example when the period C is not constant. It is a figure which shows the example in case the height h is not constant. It is a figure which shows the example in case the period C and height h are not constant. It is a figure which shows the analysis conditions of a side collision simulation (A). It is a figure which shows the deformation | transformation state of the side sill of the comparative example 4. It is a figure which shows the deformation | transformation state of the side sill of Example 1. FIG. It is a figure which shows the deformation | transformation state of the side sill of the comparative example 6. It is a figure which shows the deformation | transformation state of the side sill of Example 3. FIG. It is a figure which shows the analysis model in a side collision simulation (B). It is a figure which shows the analysis model in a side collision simulation (B). It is CC sectional drawing of FIG. It is a figure which shows the analysis model in a side collision simulation (B). It is a figure which shows the relationship between the displacement of the pole in a comparative example and an Example, and the input load to a floor panel. In addition, the vertical axis | shaft of this figure is represented by the load ratio which normalized the input load in each analysis model with the maximum input load of the comparative example 7. FIG. It is a figure which shows the state of the out-of-plane deformation | transformation of the floor panel in the comparative example 7. It is a figure which shows the state of the out-of-plane deformation | transformation of the floor panel in Example 4. FIG. It is a figure which shows the relationship between the period C and the maximum input load when the height h / period C of the convex part of a floor panel is 0.067. In addition, the vertical axis | shaft of this figure is represented by the maximum load ratio which normalized the maximum input load in each analysis model with the maximum input load of the comparative example 7. FIG. It is a figure which shows the relationship between C / (root) h of the convex part of a floor panel, and the mass efficiency of yield strength in each analysis model.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the present specification and drawings, elements having substantially the same functional configuration are denoted by the same reference numerals, and redundant description is omitted.

<First Embodiment>
As shown in FIG. 5, the floor structure 1 of the first embodiment includes a floor panel 2 and a side sill 3. The side sill 3 includes a side sill outer 4 and a side sill inner 5.

The side sill outer 4 is a member having a hat-shaped cross section perpendicular to the vehicle length direction L, and a top surface portion 4a extending in the vehicle height direction H, and an upper end portion of the top surface portion 4a in the vehicle height direction H in the vehicle width direction W. Upper vertical wall portion 4b extending to the vehicle interior side, lower vertical wall portion 4c extending from the lower end portion in the vehicle height direction H of the top surface portion 4a to the vehicle inner side in the vehicle width direction W, and the tip portion of the upper vertical wall portion 4b 4d extending upward in the vehicle height direction H and a flange portion 4e extending downward in the vehicle height direction H from the tip of the lower vertical wall portion 4c.

The side sill inner 5 is a member having a hat-shaped cross section perpendicular to the vehicle length direction L, and a top surface portion 5a extending in the vehicle height direction H, and an upper end portion of the top surface portion 5a in the vehicle height direction H in the vehicle width direction W. An upper vertical wall portion 5b extending to the vehicle outer side, a lower vertical wall portion 5c extending from the lower end portion in the vehicle height direction H of the top surface portion 5a to the vehicle outer side in the vehicle width direction W, and a tip portion of the upper vertical wall portion 5b The flange portion 5d extends upward in the vehicle height direction H, and the flange portion 5e extends downward from the front end portion of the lower vertical wall portion 5c in the vehicle height direction H.

The side sill outer 4 and the side sill inner 5 are joined by spot welding of the flange portion 4d and the flange portion 5d, and the flange portion 4e and the flange portion 5e, respectively. Note that the hat shape of the side sill outer 4 and the hat shape of the side sill inner 5 include, for example, a substantially hat shape in which the vertical wall portion is inclined with respect to the top surface portion. The angle θ formed by the top surface portion 5a of the side sill inner 5 and the

vertical wall portions

5b and 5c is 85 to 95 degrees. When the angle θ is less than 85 degrees, the moment generated in the floor panel 2 that deforms the side sill 3 to the inside of the cross section increases. Thereby, the effect of load transmission by deformation due to shearing force, that is, in-plane deformation is reduced, and the efficiency of load transmission to the floor panel 2 is reduced. The angle θ is preferably 87 degrees or more, and this can enhance the effect of suppressing the moment generated in the floor panel 2 that deforms the side sill 3 to the inside of the cross section. On the other hand, when the angle θ exceeds 95 degrees, the moment generated in the floor panel 2 that deforms the side sill 3 to the outside of the cross section increases. Thereby, the effect of load transmission by deformation due to shearing force, that is, in-plane deformation is reduced, and the efficiency of load transmission to the floor panel 2 is reduced. The angle θ is preferably 93 degrees or less, which can enhance the effect of suppressing the moment generated in the floor panel 2 that deforms the side sill 3 to the outside of the cross section.

In the first embodiment, a reinforcing member 6 is provided inside the side sill inner 5. The reinforcing member 6 is a member having a C-shaped cross section perpendicular to the vehicle length direction L, and includes a flat portion 6a and

flange portions

6b and 6c formed at both ends of the flat portion 6a. In the first embodiment, the reinforcing member 6 is disposed such that the flat surface portion 6a of the reinforcing member 6 is parallel to the top surface portion 5a of the side sill inner 5 and the flange portion 6b and the flange portion 6c extend to the vehicle outer side in the vehicle width direction W. Has been.

The flange portion 6b of the reinforcing member 6 is in contact with the inner surface of the upper vertical wall portion 5b of the side sill inner 5, and the flange portion 6c of the reinforcing member 6 is in contact with the inner surface of the lower vertical wall portion 5c of the side sill inner 5. The floor panel 2 is in contact with the outer surface of the lower vertical wall 5c of the side sill inner 5 at the end in the width direction. That is, in the lower vertical wall portion 5c of the side sill inner 5, the flange portion 6c of the reinforcing member 6 is in contact with the inner surface, and the width direction end portion of the floor panel 2 is in contact with the outer surface. The members are joined. The flange portion 6b of the reinforcing member 6 is joined to the upper vertical wall portion 5b of the side sill inner 5 by, for example, spot welding. Thereby, the reinforcing member 6 of 1st Embodiment is being fixed to the side sill inner 5 so that it may span over the upper side vertical wall part 5b and the lower side vertical wall part 5c.

The floor structure 1 of the first embodiment is configured as described above. In such a floor structure 1, for example, when a pole collides with the side sill outer 4 in a pole side collision test, a load is transmitted to the floor panel 2 via the lower vertical wall portion 5 c of the side sill inner 5. At the time of pole side collision, the upper vertical wall portion 5b and the lower vertical wall portion 5c of the side sill inner 5 try to be deformed out of plane so as to open to the outside of the cross section or to fall inside the cross section. In the floor structure 1 of the embodiment, since the reinforcing member 6 is joined in a state of being spanned between the upper vertical wall portion 5b and the lower vertical wall portion 5c, the upper vertical wall portion 5b of the side sill inner 5 and When the lower vertical wall portion 5c is deformed so as to open to the outside of the cross section, the reinforcing member 6 is pulled, and tension is generated in the reinforcing member 6. On the other hand, when the upper vertical wall portion 5b and the lower vertical wall portion 5c of the side sill inner 5 are deformed so as to fall inside the cross section, the reinforcing member 6 is compressed, and a compressive force is generated in the reinforcing member 6. These tensions or compressive forces become resistance against out-of-plane deformation of the upper vertical wall portion 5b and the lower vertical wall portion 5c, and are out of plane of the lower vertical wall portion 5c to which the floor panel 2 is joined as shown in FIG. Deformation is suppressed. Thereby, the load transmitted to the floor panel 2 is transmitted by shear deformation of the lower vertical wall portion 5c, that is, in-plane deformation, and the load transmission efficiency to the floor panel 2 is improved. As a result, the proof stress as the floor structure 1 can be improved.

In order to obtain the effect of suppressing such out-of-plane deformation, the width W ₁ of the

vertical wall portions

5b and 5c of the side sill inner 5 (the length in the vehicle width direction W from the top surface portion 5a to the

flange portions

5d and 5e). The balance between the

vertical wall portions

5b and 5c and the plate thickness t is important. In the first embodiment, the value of W ₁ / t, which is the ratio of the width W ₁ of the

vertical wall portions

5b and 5c to the plate thickness t, is less than 42.9, and the floor structure 1 that satisfies this condition Then, it becomes possible to suppress the out-of-plane deformation of the

vertical wall portions

5b and 5c. In order to further enhance the effect, W ₁ / t is preferably 40 or less, and more preferably 30 or less. The lower limit of W ₁ / t is the moldability and the side sill inner 5, the vertical wall 5b, but determined appropriately in view of securing white welding 5c and the floor panel 2, W ₁ / t that is 7.5 or more Is preferred. Further, when the side sill inner 5 and the reinforcing member 6 are joined by spot welding, the width W ₁ of the

vertical wall portions

5b and 5c is preferably 15 mm or more in order to ensure a sufficient spot hitting space.

The shape of the reinforcing member 6 is not particularly limited as long as the upper end portion is joined to the inner surface of the upper vertical wall portion 5b of the side sill inner 5 and the lower end portion is joined to the inner surface of the lower vertical wall portion 5c. On the other hand, in order to increase the tension of the reinforcing member 6 generated at the time of a side collision, the reinforcing member 6 has a shape that does not loosen, that is, a shape in which the upper vertical wall portion 5b and the lower vertical wall portion 5c are bridged over the shortest distance. Preferably there is.

Further, in the first embodiment, the reinforcing member 6 is arranged in such a direction that the flange portion 6b and the flange portion 6c of the reinforcing member 6 extend to the vehicle outer side in the vehicle width direction W. However, the flange portion 6b and the flange portion 6c are arranged. May be arranged in a direction extending toward the vehicle inner side in the vehicle width direction W. On the other hand, if the flange portion 6b and the flange portion 6c are arranged in a direction extending toward the vehicle outer side in the vehicle width direction W as in the first embodiment, spot welding can be performed by sandwiching with a gun. Becomes easier.

Second Embodiment
As shown in FIG. 7, in the floor structure 1 of the second embodiment, the reinforcing member 6 is configured by a flat plate member, and the reinforcing member 6 is disposed between the side sill outer 4 and the side sill inner 5. The flange portion 4d of the side sill outer 4 and the flange portion 5d of the side sill inner 5 are joined by, for example, spot welding in a state where the reinforcing member 6 is sandwiched therebetween. Similarly, the flange portion 4e of the side sill outer 4 and the flange portion 5e of the side sill inner 5 are also joined by, for example, spot welding in a state where the reinforcing member 6 is sandwiched therebetween. As described above, in the floor structure 1 of the second embodiment, when the side sill outer 4 and the side sill inner 5 are joined by spot welding, the reinforcing member 6 can be joined at the same time. Thereby, a welding location can be decreased and productivity can be improved.

In the second embodiment, the value of W ₁ / t, which is the ratio between the width W ₁ of the

vertical wall portions

5b and 5c of the side sill inner 5 and the plate thickness t, is less than 35.7. According to such a floor structure 1, the out-of-plane deformation that opens to the outside of the cross-section and the out-of-plane deformation that closes to the inside of the cross-section generated in the upper vertical wall portion 5 b and the lower vertical wall portion 5 c of the side sill inner 5 at the time of a side collision. Can be suppressed. In the case of the floor structure 1 in which the reinforcing member 6 is sandwiched between the side sill outer 4 and the side sill inner 5 as in the second embodiment, W ₁ / t may be 32 or less from the viewpoint of further suppressing out-of-plane deformation. preferable. The lower limit of W ₁ / t is the moldability and the side sill inner 5, the vertical wall 5b, but determined appropriately in view of securing white welding 5c and the floor panel 2, W ₁ / t that is 7.5 or more Is preferred.

<Third Embodiment>
As shown in FIG. 8, in the floor structure 1 of the third embodiment, a center pillar inner 7 is disposed between the side sill outer 4 and the side sill inner 5. The flange portion 4d of the side sill outer 4 and the flange portion 5d of the side sill inner 5 are joined together by, for example, spot welding with the center pillar inner 7 sandwiched therebetween. Similarly, the flange portion 4e of the side sill outer 4 and the flange portion 5e of the side sill inner 5 are also joined by, for example, spot welding with the center pillar inner 7 sandwiched therebetween. Thus, in the third embodiment, the center pillar inner 7 also plays a role as the reinforcing member 6 of the second embodiment. That is, in the floor structure 1 of the third embodiment, the number of parts used for vehicle body manufacturing can be reduced, and the number of welding locations can be reduced as in the floor structure 1 of the second embodiment.

In the third embodiment, the value of W ₁ / t, which is the ratio between the width W ₁ of the

vertical wall portions

5b and 5c of the side sill inner 5 and the plate thickness t, is less than 35.7. According to such a floor structure 1, the out-of-plane deformation that opens to the outside of the cross-section and the out-of-plane deformation that closes to the inside of the cross-section generated in the upper vertical wall portion 5 b and the lower vertical wall portion 5 c of the side sill inner 5 at the time of a side collision. Can be suppressed. In the case of the floor structure 1 in which the center pillar inner 7 is sandwiched between the side sill outer 4 and the side sill inner 5 as in the third embodiment, W ₁ / t is 32 or less from the viewpoint of further suppressing out-of-plane deformation. Is preferred. The lower limit of W ₁ / t is the moldability and the side sill inner 5, the vertical wall 5b, but determined appropriately in view of securing white welding 5c and the floor panel 2, W ₁ / t that is 7.5 or more Is preferred.

<Fourth embodiment>
In the first to third embodiments, the floor structure 1 for improving the yield strength by the structure of the side sill 3 has been described. In the fourth embodiment, the floor structure 1 for improving the mass efficiency of the yield strength by the shape of the floor panel 2 is explained. To do.

As shown in FIGS. 9 to 11, the floor panel 2 of the fourth embodiment includes a periodically formed convex portion 10, a bottom surface portion 11, and a ridge line that is a corner portion connecting the convex portion 10 and the bottom surface portion 11. It has a wave shape having a portion 12. The convex part 10 of the floor panel 2 in 4th Embodiment is the corner | angular part which connects the top surface part 10a, the side wall part 10b extended in the vehicle height direction H from the both ends of the top surface part 10a, and the top surface part 10a and the side wall part 10b. And a ridge line portion 10c. The ridge lines 10c and 12 are parallel to the vehicle width direction W. That is, the longitudinal direction of the convex portion 10 is parallel to the vehicle width direction W. Moreover, in the floor panel 2 of 4th Embodiment, the length of the top surface part 10a and the bottom face part 11 of the vehicle length direction L is mutually the same. Such a corrugated floor panel 2 is manufactured by imparting a shape to a flat plate by, for example, transfer by a roll or press molding.

As shown in FIG. 12, the floor structure 1 of the fourth embodiment is similar to the floor structure 1 (FIG. 5) of the first embodiment in the structure of the side sill 3 and the arrangement of the reinforcing members 6, and the

vertical wall portions

5b and 5c. The value of W ₁ / t, which is the ratio of the width W ₁ to the plate thickness t, is less than 42.9. At the end in the width direction of the floor panel 2, the top surface portion 10 a of the convex portion 10 is joined to the lower vertical wall portion 5 c of the side sill inner 5. In addition, when joining the top | upper surface part 10a of the floor panel 2 and the lower side vertical wall part 5c by spot welding, in order to ensure the space of a spot hitting point, the length of the vehicle length direction L of the top | upper surface part 10a is 15 mm. The above is preferable.

The floor structure 1 of the fourth embodiment is configured as described above. Here, the height from the bottom surface portion 11 of the corrugated portion of the floor panel 2 to the top surface portion 10a is defined as h, and the period of the convex portion 10 of the corrugated portion is defined as C. In the present specification, “period of the convex portion” means an interval from a boundary position between the convex portion 10 and the bottom surface portion 11 to a boundary position between the convex portion 10 adjacent to the convex portion 10 and the bottom surface portion 11. To do. In the case of the shape of the convex part 10 of 4th Embodiment, the period C is the space | interval from the side wall part 10b of the 1st convex part 10 to the side wall part 10b of the 2nd convex part 10 among the adjacent convex parts 10. is there. Further, as shown in FIG. 13, for example, when the side wall portion 10 b of the convex portion 10 is inclined with respect to the top surface portion 10 a, the period C is equal to the inner surface P ₁ of the side wall portion 10 b of the first convex portion 10. is the spacing from the intersection of the lower surface P ₂ of the bottom portion 11, an inner surface P ₁ of the second side wall portion 10b of the protrusion 10, until the line of intersection of the lower surface P ₂ of the bottom portion 11.

In the floor structure of the fourth embodiment, for example, out-of-plane deformation occurs in the top surface portion 10a and the bottom surface portion 11 of the floor panel 2 at the time of a side collision of an automobile, but as the period C becomes smaller, each top surface portion 10a and each bottom surface. The length of the portion 11 in the vehicle length direction L is shortened. As a result, the span where bending deformation can occur in each top surface portion 10a and each bottom surface portion 11 is shortened, and out-of-plane deformation is unlikely to occur. As a result, the proof stress of the floor panel 2 is improved. The period C of the convex portion 10 is preferably 15 to 200 mm. On the other hand, with respect to the height h of the convex portion 10, the higher the height h, the higher the bending rigidity against bending deformation with the vehicle length direction L as the rotation axis, so the proof stress of the floor panel 2 is easily improved. As a result, the proof stress of the floor structure 1 can be improved. The height h of the convex portion 10 is preferably 2 to 20 mm.

Incidentally, when the period C is reduced and the height h is increased, the amount of material used when the floor panel 2 is manufactured increases, and the mass of the floor panel 2 increases accordingly. Therefore, the balance between the cycle C and the height h is important from the viewpoint of achieving both yield strength and weight reduction. In this regard, in the floor panel 2 of the fourth embodiment, the corrugated portion is formed so that C / √h is less than 60. The floor panel 2 in which C / √h is less than 60 has improved proof mass efficiency relative to a floor panel having C / √h of 60 or more. In other words, according to the floor structure 1 of the fourth embodiment, the proof strength can be improved by the side sill structure, and the floor panel 2 joined to the side sill inner 5 has a corrugated portion where C / √h is less than 60 By having the above, the mass efficiency of the proof stress is also improved. In order to further enhance the effect of improving the mass efficiency, C / √h is preferably 55 or less, and more preferably 25 or less. In order to further enhance the effect, the floor panel is preferably a steel plate having a tensile strength of 780 MPa or more.

Further, according to the floor structure 1 as in the fourth embodiment, sufficient strength can be exerted without the floor panel 2 having a closed cross-sectional structure, so that the floor structure is configured without providing a reinforcing member such as a cross member. It is also possible to do. As a result, the indoor space or the battery mounting space can be expanded. However, from the viewpoint of improving the proof stress, the proof strength of the floor structure 1 can be further increased by further providing a reinforcing member such as a cross member to the floor structure 1 as in the fourth embodiment.

FIG. 12 shows an example in which the floor panel 2 of the floor structure 1 of the first embodiment has a corrugated portion, but the floor panel of the floor structure 1 as in the second and third embodiments. 2 may have a corrugated portion. In any case, if the corrugated portion with C / √h of less than 60 is provided on the floor panel, the mass efficiency of yield strength can be improved.

Note that the lower limit of C / √h is not particularly limited. For example, the lower limit of the period C is constrained from the viewpoint of formability of the floor panel 2, or the upper limit of the height h is constrained from the viewpoint of securing indoor space or battery mounting space, and the lower limit of C / √h is appropriately determined. C / √h is preferably 3.34 or more.

The floor panel 2 may not have a wave shape over the entire region in the vehicle length direction L, and only a part of the section in the vehicle length direction L may have a wave shape. Even in such a floor structure, if C / √h is less than 60 in the portion of the floor panel 2 to which the wave shape is given, the mass efficiency of yield strength is improved. Also in this case, C / √h is preferably 55 or less, and more preferably 25 or less. When only a part of the section in the vehicle length direction L is corrugated, the range of the corrugated portion is, for example, 200 mm or more in front of the vehicle length direction L around the collision position of the pole in the pole side collision test, and the rear It is preferable that it is 200 mm or more. In addition, by giving a wave shape over the entire region in the vehicle length direction L of the floor panel 2, a high proof stress can be exhibited regardless of the input position of the load at the time of a side collision, and the floor structure has excellent robustness. be able to.

The floor panel 2 may not have a wave shape over the entire region in the vehicle width direction W, and only the end in the width direction may have a wave shape. Even in such a floor structure, if C / √h is less than 60 in the portion to which the corrugation at the end in the width direction is given, the mass efficiency of yield strength is improved. Also in this case, C / √h is preferably 55 or less, and more preferably 25 or less. In addition, when only the width direction edge part is corrugated, the range of the corrugated part is the width of the floor panel 2 (from one side sill of the vehicle body to the other, starting from the end point in the vehicle width direction W of the floor panel 2. It is preferable that it is 1/4 or more of the length in the vehicle width direction W to the side sill.

As shown in FIG. 14, the period C of the convex part 10 of the floor panel 2 may not be constant. In this case, the “cycle C” is an average value of the cycles C of the convex portions 10. For example, as shown in FIG. 14, when four convex portions 10 having different periods are provided, the cycle of the first convex portion 10 is “C ₁ ”, and the second convex portion 10 located next to the first convex portion 10 is used. Assuming that the period of the convex part 10 is “C ₂ ” and the period of the third convex part adjacent to the second convex part 10 is “C ₃ ”, the period C in this specification is (C ₁ + C _2). + C ₃ ) / 3. Thus, even in a floor structure in which the period C is not constant, if C / √h is less than 60 in a portion where a wave shape is given, the mass efficiency of yield strength is improved. Also in this case, C / √h is preferably 55 or less, and more preferably 25 or less. If the period C is not constant, C / √h may not be less than 60 over the entire region in the vehicle length direction L. For example, even if the floor panel 2 has a wave shape over the entire region in the vehicle length direction L, the value of C / √h using the average period C and the height h of some sections in the vehicle length direction L If it is less than 60, the mass efficiency of yield strength is improved in the section. Therefore, if attention is paid to the section, the floor structure has C / √h of less than 60, and therefore it can be said to be an example of the floor structure according to the present invention.

As shown in FIG. 15, the height h of the convex part 10 of the floor panel 2 may not be constant. In this case, the “height h” is an average value of the heights h of the convex portions 10. For example, when four convex portions 10 having different heights are provided as shown in FIG. 15, the height of the first convex portion 10 is “h ₁ ”, which is located next to the first convex portion 10. Assuming that the height of the second convex portion 10 is “h ₂ ” and the height of the third convex portion located next to the second convex portion 10 is “h ₃ ”, the height h in this specification is This is a value calculated by (h ₁ + h ₂ + h ₃ ) / 3. Even in such a floor structure in which the height h is not constant, if C / √h is less than 60 in the portion where the wave shape is given, the mass efficiency of yield strength is improved. Also in this case, C / √h is preferably 55 or less, and more preferably 25 or less. When the height h is not constant, C / √h may not be less than 60 over the entire region in the vehicle length direction L. For example, even if the floor panel 2 has a wave shape over the entire region in the vehicle length direction L, the value of C / √h using the average value of the height h and the period C of some sections in the vehicle length direction L If it is less than 60, the mass efficiency of yield strength is improved in the section. Therefore, if attention is paid to the section, the floor structure has C / √h of less than 60, and therefore it can be said to be an example of the floor structure according to the present invention.

Moreover, as shown in FIG. 16, the period C and height h of the convex part 10 of the floor panel 2 may not be constant, respectively. The “cycle C” in this case is the average value of the period C of each convex portion 10 as in FIG. 14, and the “height h” is the average of the height h of each convex portion 10 as in FIG. Value. For example, as shown in FIG. 16, when four convex portions 10 having different periods and different heights are provided, the period C is calculated by (C ₁ + C ₂ + C ₃ ) / 3, and the height h Is calculated by (h ₁ + h ₂ + h ₃ ) / 3. Thus, even in a floor structure in which the period C and the height h are not constant, if C / √h is less than 60 in the portion where the wave shape is given, the mass efficiency of yield strength is improved. Also in this case, C / √h is preferably 55 or less, and more preferably 25 or less. Note that if the period C and the height h are not constant, C / √h may not be less than 60 over the entire vehicle length direction L. For example, even if the floor panel 2 has a wave shape over the entire region in the vehicle length direction L, C that is the average period of some sections in the vehicle length direction L and h that is the average height of the sections are used. If the value of C / √h is less than 60, the mass efficiency of yield strength is improved in the section. Therefore, if attention is paid to the section, the floor structure has C / √h of less than 60, and therefore it can be said to be an example of the floor structure according to the present invention.

The height h of the convex portion 10 of the floor panel 2 may be different depending on the position in the vehicle width direction W. In this case, the “height h” is an average value of heights different from each other at the position in the vehicle width direction W. Even in such a floor structure, if C / √h is less than 60 in the portion to which the wave shape is given, the mass efficiency of yield strength is improved. Also in this case, C / √h is preferably 55 or less, and more preferably 25 or less. In addition, when the height h of the convex portion 10 varies depending on the position in the vehicle width direction W, C / √h may not be less than 60 over the entire region in the vehicle width direction W. If √h is less than 60, the yield strength of the floor panel 2 is improved. The range in which C / √h in this case is less than 60 is the width of the floor panel 2 (the vehicle width direction W from one side sill of the vehicle body to the other side sill, starting from the end point of the floor panel 2 in the vehicle width direction W). The length is preferably ¼ or more of the length.

In the above description, the convex portion 10 of the floor panel 2 is configured by the top surface portion 10a, the side wall portion 10b, and the ridge line portion 10c. However, the shape of the convex portion 10 is not particularly limited. The cross-sectional shape perpendicular to the longitudinal direction may be circular. In this case, the “height h” is a height from the bottom surface portion 11 to the farthest position of the convex portion 10. Even in such a floor structure, if C / √h is less than 60 in the portion to which the wave shape is given, the mass efficiency of yield strength is improved. Also in this case, C / √h is preferably 55 or less, and more preferably 25 or less.

Further, in the above description, the

ridgeline portions

10c and 12 of the floor panel 2 are parallel to the vehicle width direction W and the floor structure is adapted to the side collision, but the

ridgeline portions

10c and 12 are arranged in the vehicle length direction L of the floor panel 2. It is good also as a floor structure corresponding to front collision or rear collision. Even in such a floor structure, if C / √h is less than 60 in the portion to which the wave shape is given, the mass efficiency of yield strength is improved. Also in this case, C / √h is preferably 55 or less, and more preferably 25 or less.

Even when the

ridge portions

10c and 12 are parallel to the vehicle length direction L, the floor panel 2 may not be corrugated over the entire region in the vehicle width direction W, and only a portion of the section in the vehicle width direction W is corrugated. There may be. Even in such a floor structure, if C / √h is less than 60 in the portion of the floor panel 2 to which the wave shape is given, the mass efficiency of yield strength is improved. Also in this case, C / √h is preferably 55 or less, and more preferably 25 or less. When only a part of the section in the vehicle width direction W has a wave shape, the range of the wave shape portion is, for example, 200 mm or more from the center position in the vehicle width direction W of the floor panel 2 to the right in the vehicle width direction W, And it is preferable that it is 200 mm or more to the left.

Even when the

ridge portions

10c and 12 are parallel to the vehicle length direction L, the floor panel 2 may not be wavy throughout the vehicle length direction L. The end portion of the vehicle length direction L (hereinafter referred to as “longitudinal direction”). Only the edge ") may be wavy. Even in such a floor structure, if C / √h is less than 60 in the portion where the corrugation at the end in the longitudinal direction is applied, the mass efficiency of yield strength is improved. Also in this case, C / √h is preferably 55 or less, and more preferably 25 or less. When only the longitudinal end portion is corrugated, the range of the corrugated portion is 1 of the length from the front end to the rear end of the floor panel 2 starting from the end point of the floor panel 2 in the vehicle length direction L. / 4 or more is preferable.

Also when the

ridges

10c and 12 are parallel to the vehicle length direction L, the period C of the convex part 10 of the floor panel 2 may not be constant. In this case, the “cycle C” is an average value of the cycles C of the convex portions 10. Even in such a floor structure, if C / √h is less than 60 in the portion to which the wave shape is given, the mass efficiency of yield strength is improved. Also in this case, C / √h is preferably 55 or less, and more preferably 25 or less. If the period C is not constant, C / √h may not be less than 60 over the entire region in the vehicle width direction W. For example, even if the floor panel 2 has a wave shape over the entire region in the vehicle width direction W, the value of C / √h using the average period C and the height h of some sections in the vehicle width direction W If it is less than 60, the mass efficiency of yield strength is improved in the section. Therefore, if attention is paid to the section, the floor structure has C / √h of less than 60, and therefore it can be said to be an example of the floor structure according to the present invention.

Also when the

ridge portions

10c and 12 are parallel to the vehicle length direction L, the height h of the convex portion 10 of the floor panel 2 may not be constant. In this case, the “height h” is an average value of the heights h of the convex portions 10. Even in such a floor structure, if C / √h is less than 60 in the portion to which the wave shape is given, the mass efficiency of yield strength is improved. Also in this case, C / √h is preferably 55 or less, and more preferably 25 or less. When the height h is not constant, C / √h may not be less than 60 over the entire region in the vehicle width direction W. For example, even if the floor panel 2 has a wave shape over the entire region in the vehicle width direction W, the value of C / √h using the average value of the height h and the period C of some sections in the vehicle width direction W If it is less than 60, the mass efficiency of yield strength is improved in the section. Therefore, if attention is paid to the section, the floor structure has C / √h of less than 60, and therefore it can be said to be an example of the floor structure according to the present invention.

Also when the

ridge line portions

10c and 12 are parallel to the vehicle length direction L, the period C and the height h of the convex portion 10 of the floor panel 2 may not be constant. In this case, “period C” is an average value of the periods C of the respective convex portions 10, and “height h” is an average value of the height h of each convex portion 10. Even in such a floor structure, if C / √h is less than 60 in the portion to which the wave shape is given, the mass efficiency of yield strength is improved. Also in this case, C / √h is preferably 55 or less, and more preferably 25 or less. If the period C and the height h are not constant, C / √h may not be less than 60 over the entire region in the vehicle width direction W. For example, even if the floor panel 2 has a wave shape over the entire area in the vehicle width direction W, C that is the average period of a part of the section in the vehicle width direction W and h that is the average height of the section are used. If the value of C / √h is less than 60, the mass efficiency of yield strength is improved in the section. Therefore, if attention is paid to the section, the floor structure has C / √h of less than 60, and therefore it can be said to be an example of the floor structure according to the present invention.

When the

ridges

10c and 12 are parallel to the vehicle length direction L, the height h of the convex portion 10 of the floor panel 2 may be different depending on the position in the vehicle length direction L. The “height h” in this case is an average value of heights that are different at the position in the vehicle length direction L. Even in such a floor structure, if C / √h is less than 60 in the portion to which the wave shape is given, the mass efficiency of yield strength is improved. Also in this case, C / √h is preferably 55 or less, and more preferably 25 or less. In addition, when the height h of the convex portion 10 varies depending on the position in the vehicle length direction L, C / √h may not be less than 60 over the entire region in the vehicle length direction L, and C / only at the longitudinal end portion. If √h is less than 60, the yield strength of the floor panel 2 is improved. In this case, the range in which C / √h is less than 60 may be ¼ or more of the length from the front end to the rear end of the floor panel 2 starting from the end point of the floor panel 2 in the vehicle length direction L. preferable.

As mentioned above, although embodiment of this invention was described, this invention is not limited to this example. It is obvious for those skilled in the art that various changes or modifications can be conceived within the scope of the technical idea described in the claims. It is understood that it belongs to.

For example, in the above embodiment, the floor panel 2 is joined to the lower vertical wall portion 5c of the side sill inner 5, but may be joined to the upper vertical wall portion 5b. Also in this case, for example, by providing the reinforcing member 6 as in the first to fourth embodiments, out-of-plane deformation of the upper vertical wall portion 5b and the lower vertical wall portion 5c of the side sill inner 5 is suppressed. The load transmission efficiency to the floor panel 2 can be improved.

<Side collision simulation (A)>
In order to evaluate the influence of the side sill structure in the conventional floor structure and the floor structure according to the present invention, a side collision simulation was performed. As shown in FIG. 17, this simulation is performed under the condition of three-point bending in which a support point 20 that supports the top surface portion 5 a of the side sill inner 5 is provided and the pole 21 collides with the side sill outer 4. In addition, a plate 22 that contacts the top surface portion 5a of the side sill inner 5 is disposed to simulate a structure assuming a battery case.

The floor structure of the analysis model used in this simulation includes a structure in which the reinforcing member shown in FIG. 3 is not provided, and a structure in which a C-shaped reinforcing member 6 is provided inward of the side sill inner 5 shown in FIG. 7 is a structure in which a flat reinforcing member 6 is provided between the side sill outer 4 and the side sill inner 5 shown in FIG. Further, in each structure, a plurality of analysis models in which the width W ₁ of the lower vertical wall portion 5c of the side sill inner 5 was changed were created and simulated. The materials of the side sill outer 4, the side sill inner 5, and the reinforcing member 6 are all 980 MPa grade steel plates, and the thickness t is 1.4 mm. The angle θ formed between the top surface portion of the side sill inner and the vertical wall portion is 90 degrees.

Side impact simulation was performed under the above conditions to evaluate the deformation state of the side sill inner. The results are shown in Table 1 below.

As shown in Table 1, in the case where the reinforcing member was not provided (Comparative Examples 1 to 3), the side sill inner had an out-of-plane deformation whose cross section opened outward. On the other hand, in the case where the C-shaped reinforcing member is provided inward of the side sill inner, the result varies depending on the value of W ₁ / t, which is the ratio of the width W ₁ of the vertical wall portion of the side sill inner to the plate thickness t. occured. For example, in the case of the comparative example 4, a large out-of-plane deformation is generated in which the cross-section closes as the vertical wall portion of the side sill inner falls down as shown in FIG. Out-of-plane deformation of the wall was suppressed. Therefore, when the reinforcing member is provided inside the side sill inner, if W ₁ / t is less than 42.9, the out-of-plane deformation of the side sill inner can be suppressed. Incidentally, according to the results of this simulation, if W ₁ / t is 40 or less, it is possible to more reliably suppress the out-of-plane deformation of the side sill inner.

Even in the case where a flat reinforcing member is provided between the side sill outer and the side sill inner, the results differ depending on the value of W ₁ / t. For example, in the case of the comparative example 6, a large out-of-plane deformation is generated in which the cross-section closes as the vertical wall portion of the side sill inner falls down as shown in FIG. Out-of-plane deformation of the wall was suppressed. Therefore, when a reinforcing member is provided between the side sill outer and the side sill inner, if W ₁ / t is less than 35.7, out-of-plane deformation of the side sill inner can be suppressed. According to the result of this simulation, if W ₁ / t is 32 or less, the out-of-plane deformation of the side sill inner can be more reliably suppressed.

<Side collision simulation (B)>
A side impact simulation of the floor structure was conducted assuming a pole side impact. The floor structure of the analysis model used in this simulation is the structure having the flat floor panel shown in FIG. 22 (Comparative Example 7) and the flat floor panel as shown in FIG. This is a structure using a cross-member for bonding (Comparative Example 8) and a corrugated floor panel shown in FIG. In addition, regarding the floor structure using the corrugated floor panel, a plurality of analysis models in which the period C and the height h of the convex portion were changed were created and simulated (Examples 4 to 13). The structure of Example 13 is a structure in which a cross member is joined to a corrugated floor panel. In this simulation, the evaluation is performed by paying attention to the proof stress of the floor panel. Therefore, the side sill is replaced with an elastic plate having a thickness of 6 mm.

Side simulation was performed by placing a 254 mm diameter pole in the center of an elastic plate simulating a side sill and moving the pole by 10 mm at 1 m / s parallel to the vehicle width direction W. The indentation amount (displacement amount) and input load of the pole at that time were recorded, and the input maximum load, that is, the proof stress was measured. Since a material having a strength of 270 to 440 MPa is usually applied to the floor panel, only the floor panel of Comparative Example 8 has a strength of 270 MPa. The other floor panels had a strength of 980 MPa, which was higher than that of a normal one. A material of 590 MPa is usually used for the cross member for pole side collision in Comparative Example 8, but in this simulation, the strength was set to 980 MPa, and the strength was higher than that of a normal one.

Table 2 below shows the conditions of the analysis model of the side collision simulation and the maximum load ratio (F ₁ / F ₀ ) obtained by normalizing the maximum input load F ₁ of each analysis model with the maximum input load F ₀ of Comparative Example 7. In addition, the mass ratio (m ₁ / m ₀ ) obtained by normalizing the mass m ₁ of each analysis model with the mass m ₀ of Comparative Example 7 is also shown.

FIG. 26 shows displacement-load ratio diagrams of Comparative Example 7 and Examples 4 and 5. The load ratio shown in FIG. 26 is a value obtained by normalizing the input load in each analysis model with the maximum input load of Comparative Example 7. As shown in FIG. 26, under any condition, after the input load reaches the maximum load, the input load decreases and changes. The reason for such transition is that the floor panel undergoes a large deformation after the input load reaches the maximum load. That is, the maximum input load is an input load before the floor panel is largely deformed, and corresponds to a proof stress. Therefore, according to FIG. 26, it is shown that the proof stress of the floor structure of Example 4 is higher than that of Comparative Example 7.

Here, FIG. 27 shows the state of the out-of-plane deformation caused by the simulation of the analysis model of Comparative Example 7. FIG. 28 shows a state of out-of-plane deformation caused by the simulation of the analysis model of the fourth embodiment. When the pole collides with the side sill, the floor panel receives a compressive load. However, in the case of a flat floor panel as shown in FIG. Deformation has occurred.

On the other hand, as shown in FIG. 28, in the case of the corrugated floor panel of Example 4, the top surface portion 10a and the bottom surface portion 11 of the convex portion are individually deformed out of plane. And the generation | occurrence | production area | region of an out-of-plane deformation at the time of seeing as the whole floor panel is narrower than the flat floor panel shown in FIG. The reason why the top surface portion 10a and the bottom surface portion 11 are individually deformed out of plane is that the ridge line portion 10c (FIG. 11) connecting the top surface portion 10a and the side wall portion 10b, and the ridge line connecting the bottom surface portion 11 and the side wall portion 10b. Since the extending direction of the portion 12 (FIG. 11) coincides with the load input direction, a strong resistance is generated against the deformation of the floor panel due to the load input, and each

ridge line portion

10c, 12 serves as a support point during bending deformation. This is because it works. The space between the supporting points is a region where the out-of-plane deformation of the floor panel can occur, but the interval between the supporting points is shortened because the floor panel is corrugated, and the span of bending deformation is changed to a flat floor panel. On the other hand, it becomes shorter. Thereby, in the floor panel of Example 4, resistance to bending deformation is increased, and the proof stress is greater than that of a floor panel that is not corrugated.

Next, when Example 4 and Example 5 are compared in FIG. 26, the maximum load in Example 5 is larger than that in Example 4, while the attenuation of the input load after reaching the maximum load is in Example 4. Is smaller. In other words, the maximum load before the large deformation of the floor panel is smaller in the fourth embodiment than in the fifth embodiment, but the input load after the large deformation of the floor panel is kept high. Therefore, it can be said that the floor structure of Example 4 is a structure having higher energy absorption performance than that of Example 5, but from the viewpoint of exhibiting high proof strength before large deformation of the floor panel, Is better. This result shows that a floor structure with high energy absorption performance is not necessarily a structure with high yield strength.

FIG. 29 shows the maximum load ratio F ₁ / F obtained by normalizing the convex portion period C of each analysis model having a corrugated floor panel and the maximum input load F ₁ of each analysis model by the maximum input load F ₀ of Comparative Example 7. The relationship with F ₀ is shown. The plot in FIG. 29 corresponds to the results of Comparative Example 11 and Examples 4 to 8 in Table 2 above, and is the case where h / C is all 0.067 and constant. When h / C is constant, the line length of the floor panel in the cross-sectional view as shown in FIG. 11 is constant, and the proof stress can be evaluated under the condition of constant mass.

29 shows that, under a constant mass condition, the proof strength of the floor panel is increased by reducing the period C rather than increasing the height h of the convex portion. In addition, the plot in the case where the period C in FIG. 29 is 30 mm corresponds to the result of Example 5 in Table 2 above, but according to Table 2 above, the plot is more implemented than Comparative Example 8 which is a floor structure having a cross member. Example 5 has a larger maximum load ratio. From this result, the floor structure of Example 5 shows that the proof stress increases so that the cross member for dealing with the pole side collision can be omitted.

FIG. 30 shows that the C / √h of the convex portion of the floor panel and the maximum load ratio F ₁ / F ₀ of each analysis model are normalized by the mass ratio m ₁ / m _{0 based} on Comparative Example 7. Show the relationship. The value on the vertical axis in FIG. 30 is the mass efficiency of the yield strength indicating the magnitude of the yield strength per mass, and the higher the value on the vertical axis, the better the balance between the yield strength and the mass.

FIG. 30 shows that the smaller the value of C / √h, the better the mass efficiency. As is clear from FIG. 30 and Table 2 above, even if the floor panel is corrugated, the proof stress mass efficiency may be inferior to that of the flat floor panel comparative example 7. That is, it is impossible to achieve both yield strength and weight reduction by simply making the floor panel corrugated. In view of the results of this simulation, the floor structure that is superior in mass efficiency of yield strength to Comparative Example 7 is a floor structure in which C / √h is less than 60. Therefore, when the corrugated portion is provided on the floor panel, C / √h is preferably less than 60 from the viewpoint of improving the mass efficiency of yield strength. By joining such a floor panel to the vertical wall portion of the side sill inner in which W ₁ / t is within a predetermined range, it is possible to improve the yield strength and to obtain an excellent mass efficiency. . Moreover, the mass efficiency of yield strength is greatly improved in the floor structure in which C / √h is 55 or less, and further 25 or less.

In addition, according to the result of Example 13 in Table 2 above, if the cross member is joined to the corrugated floor panel, the mass efficiency of yield strength is greatly improved. For this reason, for example, in the case where both improvement in yield strength and weight reduction are prioritized over securing the indoor space and the battery mounting space, it is effective to provide a cross member on the corrugated floor panel.

The present invention can be used as a floor structure attached to a vehicle such as an automobile.

DESCRIPTION OF SYMBOLS 1 Floor structure 2 Floor panel 3 Side sill 4 Side sill outer 4a Side sill outer top surface part 4b Side sill outer upper vertical wall part 4c Side sill outer lower vertical wall part 4d Side sill outer flange part 4e Side sill outer flange part 5 Side sill inner 5a Side sill inner top surface part 5b Side sill inner upper vertical wall portion 5c Side sill inner lower vertical wall portion 5d Side sill inner flange portion 5e Side sill inner flange portion 6 Reinforcement member 6a Reinforcement member flat surface portion 6b Reinforcement member flange portion 6c Reinforcement member flange portion 7 Center pillar inner 10 Convex part 10a Convex part top surface part 10b Convex part side wall part 10c Convex part ridgeline part 11 Bottom face part 12 Convex part 20 Support point 21 Pole 22 Play 101 conventional floor structure 102 floor panel 102a floor panel flange portion 103 side sill 104 side sill outer 104a side sill outer top surface portion 104b side sill outer upper vertical wall portion 104c side sill outer lower vertical wall portion 104d side sill outer flange portion 104e side sill outer flange portion 105 side sill Inner 105a Side sill inner top surface portion 105b Side sill inner upper vertical wall portion 105c Side sill inner lower vertical wall portion 105d Side sill inner flange portion 105e Side sill inner flange portion C Protrusion period H Vehicle height direction h Projection height L Vehicle length direction t Side sill inner vertical wall thickness W Vehicle width direction W ₁ Side sill inner vertical wall width θ Angle formed between the top surface of the side sill inner and the vertical wall

Claims

A floor structure,
A side sill having a side sill outer and a side sill inner;
A floor panel joined to the side sill inner;
A reinforcing member disposed inside the side sill inner,
The side sill outer has a hat-shaped cross section perpendicular to the vehicle length direction, a top surface portion, a vertical wall portion extending from the top surface portion toward the vehicle inner side in the vehicle width direction, and a flange portion extending in the vehicle height direction. Have
The side sill inner has a hat-shaped cross section perpendicular to the vehicle length direction, a top surface portion, a vertical wall portion extending from the top surface portion to the vehicle outer side in the vehicle width direction, and a flange portion extending in the vehicle height direction. Have
The side sill outer and the side sill inner are joined to each other at the flange portion,
An angle θ formed by the top surface portion of the side sill inner and the vertical wall portion of the side sill inner is 85 to 95 degrees,
The floor panel is formed on an upper vertical wall portion that is the vertical wall portion on the upper side in the vehicle height direction of the side sill inner, or on a lower vertical wall portion that is the vertical wall portion on the lower side in the vehicle height direction of the side sill inner. Joined and
The reinforcing member has an upper end joined to the upper vertical wall of the side sill inner, and a lower end joined to the lower vertical wall of the side sill inner,
The value of W 1 / t, which is the ratio between the width W 1 of the vertical wall portion of the side sill inner and the thickness t of the vertical wall portion, is less than 42.9.
In the floor structure according to claim 1,
The value of W 1 / t is 40 or less.
A floor structure,
A side sill having a side sill outer and a side sill inner;
A floor panel joined to the side sill inner;
A reinforcing member disposed between the side sill outer and the side sill inner;
The side sill outer has a hat-shaped cross section perpendicular to the vehicle length direction, a top surface portion, a vertical wall portion extending from the top surface portion toward the vehicle inner side in the vehicle width direction, and a flange portion extending in the vehicle height direction. Have
The side sill inner has a hat-shaped cross section perpendicular to the vehicle length direction, a top surface portion, a vertical wall portion extending from the top surface portion to the vehicle outer side in the vehicle width direction, and a flange portion extending in the vehicle height direction. Have
An angle θ formed by the top surface portion of the side sill inner and the vertical wall portion of the side sill inner is 85 to 95 degrees,
The floor panel is formed on an upper vertical wall portion that is the vertical wall portion on the upper side in the vehicle height direction of the side sill inner, or on a lower vertical wall portion that is the vertical wall portion on the lower side in the vehicle height direction of the side sill inner. Joined and
The flange portion of the side sill outer, the reinforcing member, and the flange portion of the side sill inner are joined together,
The value of W 1 / t, which is the ratio of the width W 1 of the vertical wall portion of the side sill inner to the plate thickness t of the vertical wall portion, is less than 35.7.
In the floor structure according to claim 3,
The value of W 1 / t is 32 or less.
In the floor structure according to claim 3 or 4,
The reinforcing member is a center pillar inner.
In the floor structure according to any one of claims 1 to 5,
The floor panel includes a corrugated portion having a ridge portion parallel to the vehicle width direction or the vehicle length direction,
The value of C / √h using the period C of the convex portion of the corrugated portion and the height h is less than 60.
In the floor structure according to claim 6,
The value of C / √h is 55 or less.
In the floor structure according to claim 6 or 7,
The ridge line portion is parallel to the vehicle width direction.
The floor structure according to any one of claims 1 to 8,
The floor panel is made of a steel plate having a tensile strength of 780 MPa or more.