JP2020111088A - Structure for vehicles - Google Patents

Abstract

To provide a structure for vehicles capable of fully exerting the performance of each of panel members against a load.SOLUTION: The board thicknesses and tensile strengths of rocker panels 12R and 12L are designated so that the bending angles of the rocker panels 12R and 12L, at which the bending moments of the rocker panels 12R and 12L reach their peaks in the event that a bending moment reacts on a rocker 10 due to a load imposed from ahead of a vehicle, will be equal to each other.SELECTED DRAWING: Figure 1

Description

The present invention relates to a vehicle structure formed of a plurality of panel members and having a closed cross-sectional shape.

Patent Document 1 below discloses a vehicle structural body having a closed cross-sectional shape by closing the opening side of a hat-shaped member having a hat-shaped cross section formed of a high-tensile steel plate with a flat closing plate. In this vehicle structure, bending rigidity and the like are ensured by providing an intermediate rib in the web portion of the hat-shaped member. The bending moment (or bending load) when the cross section of the vehicle structure collapses causes the bending when each cross section of the plurality of panel members constituting the vehicle structure such as the hat-shaped member and the closing plate collapses. It may be lower than the sum of moments (or bending loads) and the like, and the performance of each of the plurality of panel members for each load may not be fully utilized.

JP, 2012-017047, A

In view of the above facts, an object of the present invention is to obtain a vehicle structure in which the performance of the panel member against each load can be sufficiently used.

The vehicle structure according to claim 1 is formed into a closed cross-sectional shape by a plurality of panel members, and when a load or a moment acting on each of the plurality of panel members reaches a peak in the process of collapsing the cross section. The deformation amounts of the plurality of panel members are set to be the same.

The vehicle structure according to claim 1 has a closed cross-sectional shape by a plurality of panel members. Here, the amount of deformation of each of the plurality of panel members when the load or the moment applied to each of the plurality of panel members reaches a peak during the process of collapsing the cross section of the vehicle structure is made equal. Is set to. Therefore, the collapse of the cross section of the vehicle structure is suppressed until the load obtained by superposing (adding) the peak values of the loads acting on each of the plurality of panel members is applied to the vehicle structure. ..

As described above, in the vehicle structure according to claim 1, the vehicle structure is provided with a load obtained by superimposing the peak value of the load acting on each of the plurality of panel members on the vehicle structure. The collapse of the cross section of the construction structure is suppressed. Therefore, the performance of each of the plurality of panel members with respect to the load can be effectively utilized.

FIG. 1 is a rear view of a rocker as a vehicle structure according to an embodiment of the present invention viewed from a vehicle rear side. FIG. 1 is a perspective view of a rocker as a vehicle structure according to an embodiment of the present invention as viewed from the rear right side of the vehicle. In the graph schematically showing the relationship between the bending angle and the bending moment of the rocker and each rocker panel, (A) shows that the bending angle at which the bending moment of each rocker panel is the maximum is different between the right rocker panel and the left rocker panel. (B) shows a case where the bending angles of the rocker panels that maximize the bending moment are substantially the same in both rocker panels.

Next, an embodiment of the present invention will be described based on each of FIGS. 1 to 3. In each drawing, the arrow FR indicates the front side (vehicle front side) of the vehicle to which the rocker 10 as the vehicle structure according to the present embodiment is applied, the arrow LH indicates the vehicle width direction left side, and the arrow UP. Indicates the upper side of the vehicle.

<Structure of the present embodiment>
As shown in FIGS. 1 and 2, the rocker 10 includes a right rocker panel 12R as a panel member and a left rocker panel 12L as a panel member. It should be noted that one of the right rocker panel 12R and the left rocker panel 12L, which is relatively arranged on the inner side in the vehicle width direction, may be called a rocker panel inner, and is arranged relatively on the outer side in the vehicle width direction. One is also called the rocker panel outer.

The right rocker panel 12R includes a vertical wall portion 14R. The vertical wall portion 14R has a substantially flat plate shape, the longitudinal direction of the vertical wall portion 14R is approximately the vehicle front-rear direction, and the thickness direction of the vertical wall portion 14R is approximately the vehicle width direction. .. An upper wall portion 16R extends from the end portion of the vertical wall portion 14R on the vehicle upper side toward the left side in the vehicle width direction.

The upper wall portion 16R has a substantially flat plate shape, the longitudinal direction of the upper wall portion 16R is substantially the vehicle front-rear direction, and the thickness direction of the upper wall portion 16R is substantially the vehicle vertical direction. .. An upper flange portion 18R extends toward the vehicle upper side from an end portion of the upper wall portion 16R on the left side in the vehicle width direction. The upper flange portion 18R has a substantially flat plate shape, the longitudinal direction of the upper flange portion 18R is substantially the vehicle front-rear direction, and the thickness direction of the upper flange portion 18R is generally the vehicle width direction. ..

On the other hand, the lower wall portion 20R extends toward the left side in the vehicle width direction from an end portion of the vertical wall portion 14R on the vehicle lower side. The lower wall portion 20R has a substantially flat plate shape, the longitudinal direction of the lower wall portion 20R is substantially the vehicle front-rear direction, and the thickness direction of the lower wall portion 20R is substantially the vehicle vertical direction. ..

A lower flange portion 22R extends toward the vehicle lower side from an end portion of the lower wall portion 20R on the left side in the vehicle width direction. The lower flange portion 22R has a substantially flat plate shape, the longitudinal direction of the lower flange portion 22R is generally the vehicle front-rear direction, and the thickness direction of the lower flange portion 22R is generally the vehicle width direction. Has been done.

On the other hand, the left rocker panel 12L basically has a structure in which the right rocker panel 12R is laterally inverted in the vehicle width direction. Therefore, the detailed description of the configuration of the left rocker panel 12L will be omitted by replacing “R” in the configuration of the right rocker panel 12R with “L”.

Each of the right rocker panel 12R and the left rocker panel 12L configured as described above is formed by press-forming a steel plate (including, for example, a high-tensile steel plate having a tensile strength of 490 MPa or more). However, the plate thickness and mechanical characteristics (for example, tensile strength) of the steel plate (for example, including a high-tensile steel plate having a tensile strength of 490 MPa or more) for forming the left rocker panel 12L form the right rocker panel 12R. Is different from the steel plate for.

The surface on the left side in the vehicle width direction of the upper flange portion 18R of the right rocker panel 12R and the surface on the right side in the vehicle width direction of the upper flange portion 18L of the left rocker panel 12L are opposed to each other in the vehicle width direction and are in contact with each other. .. Further, the upper flange portion 18R and the upper flange portion 18L are intermittently welded and integrated in the longitudinal direction of the upper flange portions 18R and 18L by spot welding or the like, for example.

On the other hand, the surface on the left side in the vehicle width direction of the lower flange portion 22R of the right rocker panel 12R and the surface on the right side in the vehicle width direction of the lower flange portion 22L of the left rocker panel 12L are opposed to each other in the vehicle width direction. Are abutted against each other. Further, the lower flange portion 22R and the lower flange portion 22L are intermittently welded and integrated in the longitudinal direction of the lower flange portions 22R and 22L by spot welding or the like, for example. As a result, the cross-sectional shape of the rocker 10 obtained by cutting the rocker 10 in the direction orthogonal to the longitudinal direction of the rocker 10 is a closed cross-sectional shape.

<Operation and effect of this embodiment>
When a vehicle to which the present rocker 10 having the above configuration is applied collides with an obstacle or the like on the vehicle front side, that is, when a vehicle front collision such as a vehicle front collision occurs, the vehicle front end portion of the vehicle is The collision load F (see FIG. 2) is input. When the collision load F is transmitted to the rocker 10, the collision load F is input to the rocker 10 as an axial force along the longitudinal direction of the rocker 10 (that is, generally in the vehicle front-rear direction). Therefore, when the collision load F is input to the rocker 10, a moment M (see FIG. 2) that causes the vehicle front side portion of the rocker 10 to rotate toward the vehicle upper side is generated in the rocker 10. When such a collision load F exceeds a predetermined magnitude, the rocker 10 is deformed and the cross-sectional shape of the rocker 10 is collapsed.

Here, FIGS. 3A and 3B are graphs showing the relationship between the bending angle θ and the moment M in each of the rocker 10, the right rocker panel 12R, and the left rocker panel 12L. This graph is similar to the so-called “stress-strain diagram”, but the “stress-strain diagram” depends only on the material (material strength, etc.), while in FIG. B) depends not only on the materials of the rocker 10, the right rocker panel 12R, and the left rocker panel 12L, but also on the cross-sectional shapes and thicknesses of the rocker 10, the right rocker panel 12R, and the left rocker panel 12L. There is.

As shown in FIG. 3A, when the rocker 10 receives a load F from the front side of the vehicle and bending deformation occurs in the right rocker panel 12R, the bending moment M increases as the bending angle θ of the right rocker panel 12R increases. Will increase. The right rocker panel 12R is elastically deformed until the bending angle θ of the right rocker panel 12R reaches θER and the magnitude of the bending moment M reaches MER. Further, when the bending angle θ of the right rocker panel 12R exceeds θER and the bending moment M exceeds MER, the deformation of the right rocker panel 12R becomes plastic deformation. When the bending angle θ of the right rocker panel 12R reaches θPR, the bending moment M reaches the peak (maximum value) MPR, and the cross section of the right rocker panel 12R collapses. From this state, the bending moment M does not increase even if the bending angle θ of the right rocker panel 12R increases.

On the other hand, when the left rocker panel 12L is bent and deformed by the load F applied from the vehicle front side to the rocker 10, the bending moment M increases as the bending angle θ of the left rocker panel 12L increases. The left rocker panel 12L is elastically deformed until the bending angle θ of the left rocker panel 12L reaches θEL and the bending moment M reaches MEL. Further, when the bending angle θ of the left rocker panel 12L exceeds θEL and the bending moment M exceeds MEL, the deformation of the left rocker panel 12L becomes plastic deformation. When the bending angle θ of the left rocker panel 12L reaches θPL, the bending moment M reaches the peak (maximum value) MPL, and the cross section of the left rocker panel 12L collapses. From this state, the bending moment M does not increase even if the bending angle θ of the left rocker panel 12L increases.

By the way, as an example of the method of calculating the cross-sectional strength of the rocker 10, the full-section plastic strength may be used. In the calculation method using the all-section plastic strength, the load and bending moment when the entire cross section of the rocker 10 yields and reaches the plastic range from the elastic range are simply calculated, and the values are It is based on the product of the sectional line length, the thickness (plate thickness) of the rocker 10 and the yield stress. In such a calculation method, the bending moment M when the cross section of the rocker 10 including the right rocker panel 12R and the left rocker panel 12L having the mechanical characteristics shown in FIG. It is the sum of the peak MPR of the bending moment M when the section of 12R collapses and the peak MPL of the bending moment M when the section of the left rocker panel 12L collapses.

Here, as shown in FIG. 3A, the sum of the bending moments M of the rocker panels 12L and R when the bending angle θ of the rocker panels 12L and R reaches the bending angle θPR is Ms1. .. This Ms1 is smaller than the sum of the bending moment MPR and the bending moment MPL when the respective cross sections of both rocker panels 12L, R are collapsed. On the other hand, the sum of the bending moments M of the rocker panels 12L and R when the bending angle θ of the rocker panels 12L and R reaches the bending angle θPL is Ms2. This Ms2 is smaller than the sum of the bending moment MPR and the bending moment MPL when the respective cross sections of the rocker panels 12L and 12R are collapsed.

Therefore, as shown in FIG. 3(A), in the rocker 10 having such a configuration, the sum of the bending moments M of both rocker panels 12L and R in the state of the bending angle θ, that is, the state of the bending angle θ. The bending moment M of the rocker 10 does not reach the sum of MPR and MPL, which are peaks (maximum values) of the bending moments of both rocker panels 12L and 12R. Therefore, in the rocker 10 having such a configuration, the cross-section collapses at a bending moment M lower than the sum of the bending moments M of both rocker panels 12L and R, and the respective performances of both rocker panels 12L and R cannot be used up. ..

On the other hand, in the rocker 10 according to the present embodiment, when the bending angle θ of the rocker 10 reaches the angle θP, the bending moment M of the right rocker panel 12R becomes the MPR of the peak (maximum value), and the left rocker 10 The bending moment M of the panel 12L becomes the MPL of the peak (maximum value). Therefore, the sum of the bending moments M of the rocker panels 12L and 12R when the bending angle θ of the rocker 10 reaches θP is the sum of MPR and MPL. As a result, in the rocker 10 according to the present embodiment, the collapse of the cross section can be suppressed until the bending moment M reaches the sum of MPR and MPL, and the respective performances of both rocker panels 12L, R can be used up.

Next, regarding the results of the finite element method analysis in the case where the plate thicknesses T1 and T2 of the right rocker panel 12R and the left rocker panel 12L and the tensile strengths of the steel plates constituting each of the right rocker panel 12R and the left rocker panel 12L are different explain.

In this analysis, sample 1 as one of the embodiments of the invention, sample 2 as another one of the embodiments of the invention, and further three rockers 10 of the comparative example for comparison with sample 1 and sample 2 were used. To be In each of Sample 1, Sample 2, and Comparative Example, the right rocker panel 12R is arranged on the inner side in the vehicle width direction with respect to the left rocker panel 12L. Further, the interval W (see FIG. 1) between the vertical wall portion 14R of the right rocker panel 12R and the vertical wall portion 14L of the left rocker panel 12L of each of Sample 1, Sample 2, and Comparative Example is set to 30 mm. Furthermore, the interval H (see FIG. 1) between the upper wall portion 16R and the lower wall portion 20R of the right rocker panel 12R of each of Sample 1, Sample 2, and Comparative Example is set to 30 mm. The radius of curvature of the bent portion R (see FIG. 1) of both rocker panels 12L and 12R is set to 5 mm. Further, the plate thickness and the tensile strength of the steel plates forming the rocker panels 12L, R of the rockers 10 of Sample 1, Sample 2, and Comparative Example are as shown in Table 1 below.

In Table 1, the deviation ratio is the bending angle θPR of the right rocker panel 12R when the moment M of the right rocker panel 12R reaches the peak MPR, and the left rocker when the moment M of the left rocker panel 12L reaches the peak MPL. The bending angle θPL of the panel 12L and the difference ΔθP are obtained for each of Sample 1, Sample 2, and Comparative Example, and are the ratios of the difference ΔθP of Sample 2 and the difference ΔθP of Comparative Example when the difference ΔθP of Sample 1 is 1. That is, the larger this ratio is, the larger the difference ΔθP is as compared with Sample 1.

Further, in Table 1, the superimposition maximum value ratio indicates a change in the bending moment M with an increase in the bending angle θ of the right rocker panel 12R and a change in the bending moment M with an increase in the bending angle θ of the left rocker panel 12L. The superposition maximum value of the bending moment M when superposed is obtained for each of Sample 1, Sample 2 and Comparative Example, and the superposition maximum value of Sample 2 and the superposition maximum of Comparative Example when the superposition maximum value of Sample 1 is 1. It is the ratio of values.

The steel plate forming the left rocker panel 12L of the comparative example has a smaller thickness and higher tensile strength than the steel plate forming the left rocker panel 12L of Sample 1. That is, for example, the comparative example has a structure in which weight reduction is considered while suppressing a decrease in bending strength with respect to Sample 1. However, as can be seen from Table 1, the deviation ratio of the comparative example is larger than 1. Therefore, the maximum overlapping value of the bending moment M of the comparative example is smaller than the sum of the maximum values MPR and MPL of the bending moment M of the rocker panels 12L and R of the comparative example, and the maximum overlapping value of the bending moment M of the comparative example is small. Is lower than the maximum superimposed value of the bending moment M of Sample 1. For this reason, the rocker 10 of the comparative example has a cross section collapsed at a lower bending moment M than the rocker 10 of the sample 1, and it is not possible to use up the respective performances of the rocker panels 12L and 12R.

On the other hand, the sample 2 has a thinner plate thickness and a higher tensile strength than the steel plates forming each of the rocker panels 12L and 12R as compared with the sample 1. Further, in Sample 2, the plate thickness and tensile strength of the steel plate forming the right rocker panel 12R and the plate thickness and tensile strength of the steel plate forming the left rocker panel 12L are the same, and the left rocker panel of the comparative example is also used. It is set to the same size as the plate thickness and the tensile strength of the steel plate forming 12L.

The deviation ratio of this sample 2 is larger than 1, but is sufficiently smaller than that of the comparative example, and is a value sufficiently close to 1 as compared with the comparative example. Therefore, the maximum value of the bending moment M of the sample 2 is sufficiently close to the sum of the peaks (maximum values) MPR and MPL of the bending moments M of the rocker panels 12L and R of the sample 2, The superposition maximum value of the bending moment M is larger than the superposition maximum value of the bending moment M of the sample 1. Therefore, in the rocker 10 of Sample 2, collapse of the cross section is suppressed until the bending moment M becomes sufficiently large, and the performance of each of the rocker panels 12L and 12R can be used up.

Further, in order to reduce the difference ΔθP between the bending angle θPR of the right rocker panel 12R and the bending angle θPL of the left rocker panel 12L, the total plastic moment and the second moment of area of each of the right rocker panel 12R and the left rocker panel 12L are calculated. It is possible to reduce the difference between the indexes. Therefore, it is possible to design the rocker 10 having high efficiency and high pressure crushing strength with a simple and small man-hour, as compared with designing the rocker panels 12L and 12R based on the analysis by the finite element method as described above. As a result, the number of verifications in the analysis by the finite element method can be reduced, and the number of times of redesigning the rocker 10 based on the analysis result by the finite element method can be reduced.

Further, in each rocker panel 12L, R, when the cross-sectional area is increased, the bending angle θPR or the bending angle θPL at which the moment M reaches the peak (maximum value) MPR or the peak (maximum value) MPL becomes smaller and the cross-sectional area decreases. Then, the bending angle θPR or the bending angle θPL at which the moment M reaches the peak (maximum value) MPR or the peak (maximum value) MPL becomes large. For example, in order to increase the cross-sectional area of each rocker panel 12L, R, by increasing the plate thickness of the steel plate forming each rocker panel 12L, R, adding beads, ribs, etc., adding plate-shaped patches and reinforcing parts, etc. It is possible. Therefore, the rocker 10 having a small difference ΔθP between the bending angle θPR of the right rocker panel 12R and the bending angle θPL of the left rocker panel 12L can be designed relatively easily.

In addition, in the present embodiment, the rocker 10 of Sample 1 and the rocker 10 of Sample 2 described above are different in thickness and tensile strength of the steel plate forming the right rocker panel 12R and the plate thickness of the steel plate forming the left rocker panel 12L. And tensile strength were the same. However, the cross-sectional area of the right rocker panel 12R including the plate thickness of the steel plate forming the right rocker panel 12R and the cross-sectional area of the left rocker panel 12L including the plate thickness of the steel plate forming the left rocker panel 12L are different. It may be. In addition, the mechanical properties of the right rocker panel 12R including the tensile strength of the steel plate forming the right rocker panel 12R and the mechanical properties of the left rocker panel 12L including the tensile strength of the steel plate forming the left rocker panel 12L are different. Good.

In addition, in the present embodiment, the left rocker panel 12L of each of Sample 1 and Sample 2 has a shape obtained by horizontally inverting the right rocker panel 12R. However, for example, the cross-sectional shape of the right rocker panel 12R is a concave shape or a hat shape that opens to the left in the vehicle width direction, and the left rocker panel 12L has a thickness direction along the vehicle width direction and a width direction along the vehicle vertical direction. It may be flat. That is, the cross-sectional shape of the right rocker panel 12R and the cross-sectional shape of the left rocker panel 12L do not have to be symmetrical.

10 Rocker (Vehicle structure)
12L left rocker panel (panel member)
12R Right rocker panel (panel member)
MPR Bending moment peak of right rocker panel (maximum value)
MPL Bending moment peak of left rocker panel (maximum value)
θPR Bending angle when the bending moment of the right rocker panel reaches its peak θPR Bending angle when the bending moment of the left rocker panel reaches its peak

Claims (1)

Formed in a closed cross-sectional shape by a plurality of panel members, the amount of deformation of each of the plurality of panel members when the load or moment acting on each of the plurality of panel members reaches a peak in the process of collapsing the cross section. Vehicle structure set to have the same size.