JP2021172277A - Side sill structure - Google Patents

Abstract

To provide a side sill structure capable of achieving both of impact absorption performance and light-weight properties excellent upon occurrence of a collision, especially a pole side collision.SOLUTION: A side sill structure forms a cabin lower part of a vehicle, and is arranged on an outer side of in a vehicle width direction and extending in a vehicle longitudinal direction. A cross section of the side sill with a normal line extending in the vehicle longitudinal direction, is a closed cross section having a polygonal shape. In the cross section of the side sill, there is arranged a reinforcement member with a basic shape formed of a substantial flat plate, bridged in the vehicle vertical direction. In a reinforcement member 4, there is provided at least one hole 4a at any other position than a center pillar position in the vehicle lengthwise direction. Around a hole edge of the reinforcement member 4, there is a vertical wall 4b substantially in parallel to the vehicle width direction.SELECTED DRAWING: Figure 3

Description

The present invention relates to a side sill structure that achieves both high impact absorption performance and light weight in a side collision of an automobile.

The side sill of an automobile is a member that constitutes the lower part of the cabin, is arranged outside in the vehicle width direction, and extends in the vehicle length direction. The cross section of the side sill with the vehicle length direction as the normal direction is generally composed of a hat-shaped outer and inner. The side sill has a closed cross-sectional structure in which the outer portion having a substantially hat shape faces outward in the vehicle width direction, while the inner portion has a substantially hat-shaped convex portion facing inward in the vehicle width direction. The inners are joined by their respective flanges. The side sill is generally supported by a skeletal member called a cross member that extends in the vehicle width direction.

At the time of a side collision of an automobile, particularly at the time of a pole side collision, a bending load is input to the side sill supported by a cross member or the like, and the side sill is plastically deformed to absorb the impact.

As a conventional side sill structure, there are those described in Patent Document 1 and Patent Document 2.
Patent Document 1 discloses a technique for enhancing shock absorption performance by arranging a plate-shaped reinforcing member in a closed cross section of a side sill to form a truss structure. Patent Document 2 has a reinforcing plate in the cross section of the side sill, the reinforcing plate has a plurality of holes at positions where the center pillars in the vehicle length direction are arranged, and each of the plurality of holes has a triangular opening peripheral edge. However, a technique is disclosed that assumes that the rigidity of the vertical, front-rear, and inclined loads of the vehicle body is increased by forming an annular step portion that is bent in the thickness direction of the reinforcing plate at the peripheral edge of the opening.

JP-A-2007-62410 Japanese Unexamined Patent Publication No. 2017-39338

However, although Patent Document 1 discloses the arrangement of the plate-shaped reinforcing member, it does not disclose the shape of the plate-shaped reinforcing member, and there is room for improving the balance between collision performance and light weight.

Further, in Patent Document 2, the reinforcing plate has a plurality of holes at positions where the center pillars in the vehicle length direction are arranged, and an annular step bent in the thickness direction of the reinforcing plate is provided at the peripheral edge of the hole opening. Although the technology is disclosed assuming that the rigidity of the vertical, front-rear, and tilt loads of the vehicle body is increased by forming the portion, the collision position is other than the center pillar position, such as a side collision, especially a pole side collision. In some cases, it is not disclosed that the deformation behavior of the cross section and the excellent balance between the collision performance and the mass are not disclosed, and the effect thereof is not disclosed quantitatively. Further, if a hole is provided in the reinforcing plate at the position where the center pillar in the vehicle length direction is arranged, there is a problem that the resistance to out-of-plane deformation of the reinforcing member is lowered and the shock absorption performance at the time of a collision is lowered. .. Further, in Patent Document 2, each of the plurality of holes has a triangular opening peripheral edge in order to increase the rigidity of the inclined load. Therefore, the hole shape is asymmetric with respect to the plane parallel to the vehicle width direction and the vehicle length direction. Due to this asymmetry, the top surface, side surface and reinforcing plate of the side sill on the weak side of the hole are greatly deformed, and there is a concern about the effect of improving the balance between collision performance and mass.

An object of the present invention is to provide a side sill structure that has both high impact absorption performance at the time of a collision and light weight as compared with a conventional side sill.

The present inventors performed a three-point bending collision evaluation of the side sill assuming a situation in which the side sill is supported by a cross member extending in the vehicle width direction and collides with a pole.

As a result of observing the deformation state of the side sill and the reinforcing member at the time of collision in detail and then sincerely examining the shape of the side sill reinforcing member, the following findings were obtained.

By providing the reinforcing member with at least one hole other than the center pillar position in the vehicle length direction and providing a vertical wall around the hole edge, the resistance to out-of-plane deformation of the reinforcing member is increased, and the above problem can be solved.

The present invention is as listed below.
(1) A side sill structure that constitutes the lower part of the cabin of an automobile and is arranged outside in the vehicle width direction and extends in the vehicle length direction. It is a cross section, and in the cross section of the side sill, a reinforcing member which has a substantially flat plate as a basic shape and is bridged in the vertical direction of the vehicle is arranged. A side sill structure characterized in that a vertical wall is provided around the hole edge of the reinforcing member substantially parallel to the vehicle width direction.
(2) The side sill structure according to (1) above, wherein the end of the vertical wall around the hole edge of the reinforcing member is arranged inside the vehicle in the vehicle width direction.
(3) The height h of the vertical wall around the hole edge of the reinforcing member, the radius of curvature Rw of the rising ridge of the vertical wall around the hole edge of the reinforcing member, and the rising of the vertical wall around the hole edge of the reinforcing member. The above (1) or (2), wherein the relationship with the diameter Dh of the curvature stop of the ridge line portion satisfies h ≧ 5 mm and Dh / (Dh-2h-πRw) ≦ 1.40. Side sill structure.
(4) Any of the above (1) to (3), wherein the center between the adjacent holes is arranged at the center between the cross members among at least one or more holes of the reinforcing member. Side sill structure described in Crab.
(5) It is composed of a substantially hat-shaped outer, a substantially hat-shaped inner, and the reinforcing member, the outer and the inner are connected by a flange, and the reinforcing member is connected to the side surface of the outer and the side surface of the inner. The side sill structure according to any one of (1) to (4) above, wherein the flange is connected to the flange at a distance of 20 mm or less in the vehicle width direction.
(6) The above (1) to (4), which are composed of a substantially hat-shaped outer, a substantially hat-shaped inner, and the reinforcing member, and the reinforcing member is connected to the outer by a flange of the inner. ) Is described in any of the side sill structures.
(7) The side sill structure according to any one of (1) to (6) above, wherein the side sill is made of a steel plate having a tensile strength of 780 MPa or more.

According to the present invention, it is possible to provide a side sill structure that has both high impact absorption performance at the time of collision and light weight.

It is a figure which shows the side sill of this invention. It is a figure which shows the cross section of the conventional side sill. It is a figure which shows the cross section of the side sill of the 1st Embodiment of this invention. It is a figure which shows the cross section of the side sill of the 2nd Embodiment of this invention. It is a figure which shows the reinforcing member of the 1st Embodiment of this invention. It is a figure which shows the cross section of the reinforcing member of 1st Embodiment of this invention. It is a figure which shows the reinforcing member of the 3rd Embodiment of this invention. It is a figure which shows the deformation of the conventional side sill. It is a figure which shows the modification of the side sill of the 1st Embodiment of this invention. It is a figure which shows the modification of the side sill of the 2nd Embodiment of this invention. It is a figure which shows the evaluation condition of three-point bending. It is a figure which shows the energy absorption efficiency of a comparative example and an Example. It is a figure which shows the relationship between the height of the vertical wall around the hole edge of a reinforcing member, and the energy absorption efficiency.

Hereinafter, the side sill structure according to the embodiment of the present invention will be described with reference to the drawings. In the present specification and the drawings, elements having substantially the same functional configuration are designated by the same reference numerals, so that duplicate description will be omitted.

As shown in FIG. 1, the side sill 1 is supported by a cross member 11 arranged on the upper part of the floor panel 10. At the time of the pole side collision, the side sill 1 is plastically deformed by the bending load supported by the cross member 11 and absorbs the impact.

In this bending load, the condition in which the side sill 1 is most difficult to obtain the plastic deformation resistance is the case where the poles collide with each other at the central positions of the plurality of cross members 11, and therefore, in this condition, the plastic deformation resistance, that is, energy absorption It is important to achieve both lightness.

As shown in the first embodiment of FIG. 3, the side sill 1 is composed of an outer 2, an inner 3, and a reinforcing member 4. The outer 2 has a substantially hat shape and a convex portion, that is, the outer top surface 2a faces the outside in the vehicle width direction W, and the inner 3 has a substantially hat shape and the convex portion, that is, the inner top surface 3a faces the inside of the vehicle width direction W. It is arranged facing the surface and forms a closed cross section. The outer 2 and the inner 3 are connected by the outer flange 2c and the inner flange 3c. For example, spot welding is used for bonding.

The reinforcing member 4 is arranged in a cross section formed by the outer 2 and the inner 3. The reinforcing member 4 has a substantially flat plate shape, and in the first embodiment shown in FIG. 3, the reinforcing member 4 is coupled to the outer flange 2c and the inner flange 3c, respectively. For example, spot welding is used for bonding. Further, the reinforcing member 4 is provided with at least one reinforcing member hole 4a. The reinforcing member hole 4a is provided at a position other than the center pillar position in the vehicle length direction L. That is, the reinforcing member hole 4a is not provided at the position of the center pillar in the vehicle length direction L. The alternate long and short dash line in FIG. 5 indicates the center between adjacent cross members 11, that is, the center of one reinforcing member hole 4a is located at the center between the cross members 11. Further, the vertical wall 4b around the hole edge of the reinforcing member hole 4a is provided so as to be substantially parallel to the vehicle width direction from the reinforcing member hole 4a, and the end portion of the vertical wall 4b around the hole edge of the reinforcing member hole 4a is provided. It is located on the outer 2 side. On the other hand, FIG. 2 is a diagram showing a cross section of the conventional side sill 100. In the conventional side sill 100 shown in FIG. 2, the vertical wall 4b around the hole edge of the reinforcing member hole 4a is not provided.

In the deformation of the conventional side sill 100 shown in FIG. 8, the reinforcing member 4 is out-of-plane deformed toward the outer 2 side in the vehicle width direction W, and the direction of deformation is the same for the side sill 1 of the present invention shown in FIG. However, in the side sill 1 of the present invention, the vertical wall 4b around the hole edge of the reinforcing member hole 4a is provided substantially parallel to the vehicle width direction, so that the resistance when the reinforcing member 4 is deformed out of the plane is increased. As a result, the resistance to out-of-plane deformation of the side sill 1 of the present invention is increased as compared with the conventional side sill 100, and the side sill 1 of the present invention can achieve both excellent energy absorption performance and light weight.

Next, the side sill 1 of the second embodiment shown in FIG. 4 will be described. In the side sill 1 of the second embodiment, the end portion of the vertical wall 4b around the hole edge of the reinforcing member hole 4a is arranged on the inner 3 side with respect to the side sill 1 of the first embodiment. The arrangement of the reinforcing member holes 4a in the second embodiment is the same as that in the first embodiment (FIG. 5).

The reinforcing member 4 of the side sill 1 of the second embodiment shown in FIG. 10 is out-of-plane deformed to the outer side in the vehicle width direction W like the side sill 1 of the first embodiment and the conventional side sill 100. As a result, the end of the vertical wall 4b around the hole edge of the reinforcing member hole 4a of the first embodiment is subjected to tensile deformation, while the vertical wall 4b around the hole edge of the reinforcing member hole 4a of the second embodiment is deformed. The end of is compressed and deformed. As shown in Examples described later, the side sill 1 of the second embodiment has a higher absorption energy than the side sill 1 of the first embodiment. From this, the side sill 1 is further excellent by arranging the vertical wall 4b around the hole edge of the reinforcing member hole 4a so that the end portion of the vertical wall 4b around the hole edge of the reinforcing member hole 4a is compressed and deformed. It is possible to achieve both energy absorption performance and light weight.

Next, the side sill 1 of the third embodiment having the reinforcing member 4 shown in FIG. 7 will be described. The alternate long and short dash line in FIG. 7 shows the center between adjacent cross members 11, as in FIG. The reinforcing member 4 of the side sill 1 of the third embodiment is arranged at the center between the adjacent cross members 11 in at least one or more reinforcing member holes 4a so that the center between the adjacent reinforcing member holes 4a is the center. ..

From the embodiment described later, with respect to the reinforcing member 4 of the side sill 1, the center between the adjacent reinforcing member holes 4a is arranged at the center between the adjacent cross members 11 among at least one or more reinforcing member holes 4a. , The side sill 1 makes it possible to achieve both excellent energy absorption performance and light weight when a pole collides with the center between the cross members 11.

Next, from the viewpoint of achieving both excellent energy absorption performance and light weight, the height h of the vertical wall 4b around the hole edge of the reinforcing member hole 4a and the vertical wall 4b around the hole edge of the reinforcing member hole 4a shown in FIG. The relationship between the radius of curvature Rw of the rising ridge and the diameter Dh of the curvature stop of the rising ridge of the vertical wall 4b around the hole edge of the reinforcing member hole 4a is h ≧ 5 mm and Dh / (Dh-2h-πRw). It is preferable to satisfy ≦ 1.40. Here, Dh / (Dh-2h-πRw) means a hole expansion rate, and when the hole expansion rate exceeds 1.40, a vertical wall around the hole edge is formed by flange-up processing using a metal material. At that time, the end portion of the vertical wall is locally thinned or cracked, and does not contribute to the improvement of the energy absorption performance. The diameter Dh of the curvature stop of the rising ridge of the vertical wall 4b means the outer diameter of the boundary between the curved surface of the rising ridge of the vertical wall 4b around the hole edge of the reinforcing member hole 4a and the outer plane thereof. ..

From the examples described later, by satisfying h ≧ 5 mm, the side sill 1 can achieve both excellent energy absorption performance and light weight. Increasing h increases the resistance to out-of-plane deformation. However, the effect is insufficient when h <5. On the other hand, when Dh / (Dh-2h-πRw)> 1.40, the edge of the vertical wall 4b around the hole edge of the reinforcing member hole 4a is formed when the vertical wall 4b around the hole edge of the reinforcing member hole 4a is formed. The tensile deformation of the part becomes high, and in order to avoid breakage, there are difficulties in molding such as increasing the number of molding steps and complicating the molding die.

Although preferred embodiments of the present invention have been described above, the present invention is not limited to such examples. It is clear that a person skilled in the art can come up with various modifications or modifications within the scope of the technical idea described in the claims, and of course, the technical scope of the present invention also includes them. It is understood that it belongs to.

For example, in the first to third embodiments, the shape of the reinforcing member hole 4a is a circle, but the shape does not necessarily have to be a circle, and the circumference of the hole edge of the reinforcing member hole 4a is not limited to the shape of the reinforcing member hole 4a. By providing the vertical wall 4b of the above, the effect of the present invention can be enjoyed.

For example, the reinforcing member hole 4a may be a rounded quadrangle. In that case, the height h of the vertical wall 4b around the hole edge of the member hole 4a in the curved portion of the reinforcing member hole 4a, the radius of curvature Rw of the rising ridge of the vertical wall 4b around the hole edge of the reinforcing member hole 4a, and the reinforcing member. It is preferable that the relationship of the length Dh of the curvature stop of the rising ridge of the vertical wall 4b around the hole edge of the hole 4a satisfies Dh / (Dh-2h-πRw) ≦ 1.40, and the reinforcing member hole 4a It is preferable that the height h of the vertical wall 4b around the hole edge of the member hole 4a in the straight portion of the member hole 4a satisfies h ≧ 5 mm. The length Dh of the curvature stop of the rising ridge of the vertical wall 4b is a rounded quadrangle with respect to the boundary between the curved surface of the rising ridge of the vertical wall 4b around the hole edge of the reinforcing member hole 4a and the outer plane thereof. Means the distance between two boundaries on two opposite sides of.

Further, the reinforcing member hole 4a may be pentagonal. However, when the reinforcing member hole 4a has an asymmetrical shape with respect to the surfaces parallel to the vehicle width direction W and the vehicle length direction L, the top surface, side surface, and reinforcing plate of the side sill on the weak side of the hole are greatly deformed and collide. The effect of balancing performance and mass may not be fully enjoyed. Therefore, the hole shape of the reinforcing member hole 4a is preferably a shape substantially symmetrical with respect to the plane parallel to the vehicle width direction W and the vehicle length direction L.

Further, in the first to third embodiments, the reinforcing member 4 is connected by the outer flange 2c and the inner flange 3c, but the effect of the present invention is also obtained when the connecting position of the reinforcing member 4 is the outer side surface 2b or the inner side surface 3b. Can be enjoyed.

When the reinforcing member 4 is connected by the outer side surface 2b or the inner side surface 3b, the connecting portion of the reinforcing member 4 is preferably arranged at a distance of 20 mm or less in the vehicle width direction W with respect to the flange. When this distance is 20 mm or more, the deformation mode of the cross section of the side sill 1 changes, and the effect of the present invention may not be fully enjoyed.

As the material constituting the side sill 1 of the present invention, a metal material (for example, steel plate, aluminum, titanium) is selected. Further, a resin material or a carbon fiber material may be used. A material having high specific strength and specific rigidity is preferable.

For the conventional and the side sill structures of the present invention, a simulation of three-point bending in which a part of the side sill structure shown in FIG. 11 was cut out was carried out. The conventional side sill structure is a structure in which the vertical wall 4b around the hole edge of the reinforcing member hole 4a is excluded as shown in FIG. 2 with respect to the side sill structure shown in FIG. 3 (Comparative Example 1). The side sill structure of the present invention is a structure in which the reinforcing member holes 4a are arranged in FIG. 7 with respect to the structure of FIG. 3 (Example 1), the structure of FIG. 4 (Example 2), and FIG. 4 (Example 3). Is. In Examples 1 to 3, the height h of the vertical wall 4b around the hole edge of the reinforcing member hole 4a is 7 mm, and the diameter Dh of the curvature stop of the rising ridge of the vertical wall 4b around the hole edge of the reinforcing member hole 4a is 60 mm. The radius of curvature Rw of the rising ridge of the vertical wall 4b around the hole edge of the reinforcing member hole 4a was 5 mm, and the spacing Lh of the reinforcing member holes 4a was 80 mm at equal intervals. Further, with respect to the third embodiment, the radius of curvature Rw of the rising ridge of the vertical wall 4b around the hole edge of the reinforcing member hole 4a is 2.5 mm, and the height h of the vertical wall 4b around the hole edge of the reinforcing member hole 4a is set. A structure in which the pitch was changed from 2.5 to 12.5 mm at a pitch of 2 mm was also prepared. In each structure, the side sill length L1 was 800 mm, the connection between the outer 2 and the inner 3 and the reinforcing member 4 was spot welded, and the spot welding pitch was 30 mm. The outer 2 and the inner 3 having any structure were made of a steel plate of 980 MPa class and a plate thickness of 1.4 mm, and the reinforcing member 4 was made of a steel plate of 980 MPa class and a plate thickness of 1.0 mm.

The radius of curvature Ri of the three-point bending impactor (pole) is 127 mm, the radius of curvature Rs of the support points is 60 mm, the distance between the support points is 300 mm, the impactor speed Vi is 1 m / s, and the distance between the support points of the side sill structure is set. I moved it toward the center. That is, the situation where the pole collides with the center between adjacent cross members was simulated. The load generated between the pole and the side sill structure and the displacement of the pole were measured. The energy absorption amount was an integral value of the load with respect to the displacement of the pole, and the energy absorption amount at the time when the displacement of the pole was 100 mm was evaluated.

FIG. 12 compares the energy absorption efficiencies of Comparative Example and Example. The vertical axis of the figure is the value obtained by dividing the energy absorption amount of Example by the mass of the side sill structure (energy absorption amount / mass) and the energy absorption amount of Comparative Example 1 divided by the mass of the side sill structure (energy absorption amount). / Mass) indicates the standardized value. If this standardized value exceeds 1, it means that both excellent energy absorption performance and light weight can be achieved as compared with the conventional side sill structure. As shown in FIG. 12, the values of all the examples exceed 1. From this, it was shown that the side sill structure of the present invention provided with the vertical wall 4b around the hole edge of the reinforcing member hole 4a can achieve both excellent energy absorption performance and light weight.

Further, as shown in FIG. 12, the value of Example 2 is higher than that of Example 1. From this, it was shown that by arranging the vertical wall 4b around the hole of the reinforcing member hole 4a on the inner 3 side, the side sill 1 can achieve both excellent energy absorption performance and light weight.

Next, the value of Example 3 is higher than that of Example 2. From this, with respect to the reinforcing member 4 of the side sill 1, the side sill is arranged by arranging the center between the adjacent reinforcing member holes 4a in the center between the adjacent cross members among at least one or more reinforcing member holes 4a. It was shown that when the pole collides with the center between the cross members, it is possible to achieve both excellent energy absorption performance and light weight.

Next, FIG. 13 shows the relationship between the height of the vertical wall 4b around the hole edge of the reinforcing member hole 4a and the energy absorption efficiency. The horizontal axis of the figure is the height of the vertical wall 4b around the hole edge of the reinforcing member hole 4a, and the vertical axis is the energy absorption amount / mass of the embodiment as in FIG. 12, standardized by the energy absorption amount / mass of Comparative Example 1. Indicates the value. When the height of the vertical wall 4b around the hole edge of the reinforcing member hole 4a is 0 to 4.5 mm, the value on the vertical axis increases sharply, and when it is 4.5 to 6.5 mm, the value on the vertical axis gradually increases. , The values on the vertical axis after that are almost unchanged. From this, it was shown that there is a preferable range of the height of the vertical wall 4b around the hole edge of the reinforcing member hole 4a from the viewpoint of achieving both excellent energy absorption performance and light weight.

The present invention can be applied to a side sill attached to an automobile or the like.

1 Side sill 2 Outer 2a Outer top surface 2b Outer side surface 2c Outer flange 3 Inner 3a Inner top surface 3b Inner side surface 3c Inner flange 4 Reinforcing member 4a Reinforcing member hole 4b Vertical wall 10 Floor panel 11 Cross member 100 Conventional side sill L Vehicle length direction W Vehicle width direction V Vehicle height direction Rw Radius of curvature of the rising ridge of the vertical wall around the hole edge of the reinforcing member Dh Radius of curvature of the rising ridge of the vertical wall around the hole edge of the reinforcing member h Vertical wall height Lh Reinforcing member hole spacing Ri Impactor radius of curvature Vi Impactor speed Rs Support point radius of curvature Ls Support point spacing L1 Side sill length

Claims (7)

It is a side sill structure that constitutes the lower part of the cabin of an automobile, is arranged outside in the vehicle width direction, and extends in the vehicle length direction.
The cross section of the side sill with the vehicle length direction as the normal is a closed cross section having a polygonal shape.
In the cross section of the side sill, a reinforcing member having a substantially flat plate as a basic shape and being bridged in the vertical direction of the vehicle is arranged, and the reinforcing member is provided with at least one or more holes other than the center pillar position in the vehicle length direction. Has been
A side sill structure characterized in that a vertical wall is provided around the hole edge of the reinforcing member substantially parallel to the vehicle width direction. The side sill structure according to claim 1, wherein the end of the vertical wall around the hole edge of the reinforcing member is arranged inside the vehicle in the vehicle width direction. The height h of the vertical wall around the hole edge of the reinforcing member, the radius of curvature Rw of the rising ridge of the vertical wall around the hole edge of the reinforcing member, and the rising ridge of the vertical wall around the hole edge of the reinforcing member. The side sill structure according to claim 1 or 2, wherein the relationship with the diameter Dh of the curvature stop satisfies h ≧ 5 mm and Dh / (Dh-2h-πRw) ≦ 1.40. The one according to any one of claims 1 to 3, wherein the center between the adjacent holes among at least one or more holes of the reinforcing member is arranged at the center between the cross members. Side sill structure. It is composed of a substantially hat-shaped outer, a substantially hat-shaped inner, and the reinforcing member, the outer and the inner are connected by a flange, the reinforcing member is connected to the side surface of the outer and the side surface of the inner, and the flange. The side sill structure according to any one of claims 1 to 4, wherein the side sill structure is connected to the vehicle at a distance of 20 mm or less in the vehicle width direction. Any one of claims 1 to 4, which is composed of a substantially hat-shaped outer, a substantially hat-shaped inner, and the reinforcing member, and the reinforcing member is joined to the outer by a flange of the inner. Side sill structure described in. The side sill structure according to any one of claims 1 to 6, wherein the side sill is made of a steel plate having a tensile strength of 780 MPa or more.

Images