JP2021172117A - Vehicular skeleton member and electric vehicle - Google Patents

Abstract

To improve the energy absorption efficiency (the mass efficiency of absorbed energy) of a vehicular skeleton member.SOLUTION: A vehicular skeleton member includes a hat member 10 and a closing plate 20. The hat member 10 includes a top plate 11, two vertical walls 12, and two flanges 13. The two vertical walls 12 each include a plurality of grooves 31 that extends in the vertical direction (Z-direction) to the lengthwise direction (Y-direction) of the hat member 10. Each groove 31 includes one ridge line and two side faces. The ridge line extends in the vertical direction (Z-direction) to the lengthwise direction (Y-direction) of the hat member 10. The two side faces are respectively connected to the ridge line. A depth a of the groove 31 in the cross-section parallel to the top plate 11, a width b of the groove, and a height e of the vertical wall 12 in the vertical direction (Z-direction) to the top plate 11 satisfy 0.2≤a/e≤0.3 and 0.1≤b/e≤0.3.SELECTED DRAWING: Figure 1

Description

The present invention relates to an automobile skeleton member that exhibits high energy absorption efficiency, for example, in the event of an automobile collision.

In recent years, fuel efficiency regulations have become stricter all over the world, and there is a demand for improved collision performance and weight reduction of automobile bodies. However, simply replacing the material of the automobile skeleton member with a material having high strength and a thin plate thickness may cause early buckling at the time of a collision due to a decrease in rigidity depending on the shape of the skeleton member, and the energy absorption efficiency is not necessarily high. Is not always obtained. The energy absorption performance increases as the number of plastically deformed parts of the skeleton member increases, but if buckling occurs early at the time of collision, many parts that do not plastically deform remain, and even if the material strength is increased, the energy absorption performance is improved. The degree of improvement is small. For this reason, studies are underway on skeletal members that can utilize the original strength of the material so that buckling does not occur at an early stage in the event of a collision. Further, in electric vehicles, the development of a vehicle body structure in which a large-capacity battery is mounted under the floor is being promoted, and the skeletal members such as side sills are being improved.

As a technique for improving energy absorption performance, Patent Document 1 discloses that a bulkhead having a substantially U-shaped cross section is provided between a side sill and a cross member. The bulkhead of Patent Document 1 is composed of a front portion, a rear side surface portion, and a flange, and has recesses in the front surface portion and the rear side surface portion. Patent Document 2 discloses a shock absorbing member in which a bellows-shaped deformation promoting means is provided on the hollow member. In the shock absorbing member of Patent Document 2, when a bending load due to an impact is applied, the bellows-shaped deformation promoting means buckles to convert the bending load into a compression load in the longitudinal direction to suppress cross-sectional collapse. There is. Patent Document 3 discloses a metal absorber in which a concave or convex bead is formed on a vertical wall of a hat member.

Japanese Unexamined Patent Publication No. 2006-205977 Japanese Unexamined Patent Publication No. 2006-207679 Japanese Unexamined Patent Publication No. 2008-265738

Since the vehicle body structure of Patent Document 1 is not a structure intended to suppress buckling of the side sill itself, there is room for improvement from the viewpoint of improving energy absorption performance by utilizing the material strength. Further, when the present inventor carried out a simulation on the shock absorbing member of Patent Document 2, many parts of the shock absorbing member that were not plastically deformed remained, and from the viewpoint of improving the energy absorption performance by utilizing the material strength. Then there is room for improvement. The absorber of Patent Document 3 is intended to protect the legs of a pedestrian in the event of a collision between a pedestrian and an automobile, and there is room for improvement in terms of improving the energy absorption performance on the vehicle body side.

The present invention has been made in view of the above problems, and an object of the present invention is to improve the energy absorption efficiency (mass efficiency of absorbed energy) of an automobile frame member.

One aspect of the present invention for solving the above problems is an automobile skeleton member, which includes a hat member and a closing plate, and the hat member includes a top plate, two vertical walls, and two flanges. The two vertical walls are respectively between the top plate and the flange, the two vertical walls face each other, the two flanges are each joined to the closing plate, and the two vertical walls are each said. It comprises a plurality of grooves extending in a direction perpendicular to the longitudinal direction of the hat member, the groove having one ridge and two side surfaces, the ridge extending in a direction perpendicular to the longitudinal direction of the hat member, said. The two side surfaces are connected to the ridgeline, respectively, and the depth a of the groove portion in the cross section parallel to the top plate, the width b of the groove portion, and the height e of the vertical wall in the direction perpendicular to the top plate. Is characterized in that the relationship of 0.2 ≦ a / e ≦ 0.3 and 0.1 ≦ b / e ≦ 0.3 is satisfied.

One aspect of the present invention from another aspect is an automobile skeleton member, comprising a hollow member, the hollow member comprising a top plate, a bottom plate, and two vertical walls, the top plate and the bottom plate. Facing each other, the two vertical walls are between the top plate and the bottom plate, respectively, the two vertical walls face each other, and the two vertical walls extend in a direction perpendicular to the longitudinal direction of the hollow member. A plurality of grooves are provided, the groove includes one ridge and two sides, the ridge extends in a direction perpendicular to the longitudinal direction of the hollow member, and the two sides are each connected to the ridge. The depth a of the groove in the cross section parallel to the top plate, the width b of the groove, and the height e of the vertical wall in the direction perpendicular to the top plate are 0.2 ≦ a / e ≦ 0. It is characterized in that it satisfies the relationship of 0.3 and 0.1 ≦ b / e ≦ 0.3.

The energy absorption efficiency of the automobile frame member can be improved.

It is a perspective view which shows the schematic structure of the automobile skeleton member which concerns on 1st Embodiment. It is a figure which shows the cross section perpendicular to the member longitudinal direction in the part where the groove part is not provided of the automobile skeleton member. It is a figure which shows the periphery of the side sill in the cross section perpendicular to the vehicle height direction of an electric vehicle. It is a top view around the groove formation part of a hat member. It is a side view around the groove formation part of a hat member. FIG. 5 is a cross-sectional view taken along the line AA in FIG. It is a figure which shows an example (out-of-plane bending mode) of the deformation mode of the automobile skeleton member. FIG. 7 is a cross-sectional view taken along the line BB in FIG. It is a figure which shows an example (in-plane folding mode) of the deformation mode of an automobile skeleton member. It is a figure which shows an example (shaft crushing mode) of the deformation mode of the automobile skeleton member. FIG. 5 is a cross-sectional view taken along the line CC in FIG. It is a figure for demonstrating the radius of curvature d of a ridge line R. This figure is a view of the top plate of the hat member from above. It is a perspective view which shows the schematic structure of the automobile skeleton member which concerns on 2nd Embodiment. It is a figure corresponding to the AA cross section in FIG. 5 of the automobile frame member which concerns on 2nd Embodiment. It is a figure corresponding to the AA cross section in FIG. 5 which shows the shape example of the groove part. It is a figure corresponding to the AA cross section in FIG. 5 of the automobile frame member which concerns on 3rd Embodiment. It is a figure corresponding to the AA cross section in FIG. 5 of the automobile skeleton member which has the groove part in both the 1st hat member and the 2nd hat member. It is a perspective view which shows the schematic structure of the automobile skeleton member which concerns on 4th Embodiment. It is a figure corresponding to the AA cross section in FIG. 5 of the automobile frame member which concerns on 4th Embodiment. It is a figure which shows the shape example of the groove part. It is a figure which shows the shape example of the groove part. It is a figure which shows the shape example of the groove part. It is a figure which shows the shape example of the groove part. It is a figure which shows the analysis model in a collision simulation. It is a figure which shows the result of the simulation (1). It is a figure which shows the relationship between a / e, b / e, and a deformation mode in simulation (2).

Hereinafter, an embodiment according to 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.

<First Embodiment>
FIG. 1 is a diagram showing a schematic configuration of an automobile skeleton member 1 according to the first embodiment. The automobile skeleton member 1 is a member that receives a bending load such as a side sill or a bumper beam. The automobile skeleton member 1 of the first embodiment has a hat member 10 having a hat-shaped cross section perpendicular to the member longitudinal direction (Y direction in FIG. 1) and a flat plate-shaped bottom plate joined to the hat member 10. It has a closing plate 20 of the above. The X, Y, and Z directions shown in FIG. 1 are perpendicular to each other. When the automobile frame member 1 is, for example, a member constituting a side sill, the X direction is the vehicle height direction and the Y direction is the vehicle length. The direction and the Z direction are the vehicle width directions. When the automobile skeleton member 1 is, for example, a member constituting a bumper beam, the X direction is the vehicle height direction, the Y direction is the vehicle width direction, and the Z direction is the vehicle length direction.

As shown in FIG. 2, the hat member 10 has a top plate 11, two vertical walls 12 connected to the top plate 11, and two flanges 13 connected to the vertical wall 12. The two vertical walls 12 are located between the top plate 11 and the flange 13, respectively, and the two vertical walls 12 face each other. In the first embodiment, the automobile skeleton member 1 is formed by joining the two flanges 13 of the hat member 10 and the closing plate 20. The hat member 10 is formed of, for example, a steel material having a tensile strength of 440 to 1500 MPa, but the material of the hat member 10 is not particularly limited, and may be, for example, an aluminum alloy member or a magnesium alloy member. Similarly, the closing plate 20 is made of, for example, a steel material having a tensile strength of 440 to 1500 MPa, but the material of the closing plate 20 is not particularly limited, and may be, for example, an aluminum alloy member or a magnesium alloy member.

When the automobile skeleton member 1 is attached to the vehicle body, the top plate 11 of the hat member 10 may be arranged outside the vehicle or inside the vehicle with respect to the closing plate 20. Especially in the case of the side sill, it is preferable that the top plate 11 is arranged on the outside of the vehicle with respect to the closing plate 20. This is because if the flange of the hat member is on the outside of the vehicle, the flange and the door interfere with each other and the door does not close. Further, the automobile skeleton member 1 is preferably applied to an electric vehicle. This is because the side sill absorbs the impact to avoid damage to the battery placed inside the vehicle from the side sill. FIG. 3 is a diagram showing the periphery of the side sill 41 in a cross section perpendicular to the vehicle height direction of the electric vehicle 40. When the automobile skeleton member 1 is a member constituting the side sill 41 as shown in FIG. 3, the closing plate 20 is adjacent to the battery 42 arranged under the floor panel (not shown), and the top plate 11 Is preferably arranged on the outside of the vehicle, out of the outside and the inside of the vehicle. In addition, in this embodiment and the embodiment described later, the top plate 11 is arranged on the outside of the vehicle, out of the outside of the vehicle and the inside of the vehicle.

As shown in FIGS. 1 and 4 to 6, the hat member 10 of the first embodiment has a groove portion 31 extending in a direction perpendicular to the longitudinal direction of the member. From the viewpoint of effectively improving the energy absorption efficiency, the groove portion 31 is located between the vertical wall 12 and the flange 13 from the ridge line portion 14 between the top plate 11 and the vertical wall 12 as shown in FIGS. 1 and 6. It is preferable that the vertical wall 12 is formed so as to straddle the ridgeline portion 15, that is, from the vehicle outer end portion to the vehicle inner end portion of the vertical wall 12. Grooves 31 are provided on both of the pair of vertical walls 12. The molding method of the groove portion 31 is not particularly limited, and for example, molding is performed by repeatedly performing press working after molding the hat member 10 and gradually increasing the depth of the groove portion 31. In the present specification, a portion where the groove portion 31 as shown in FIG. 4 is formed is referred to as a “groove forming portion 30”. Further, as shown in FIG. 6, in the present specification, the top plate 11 at the groove forming portion 30 is referred to as “groove top plate 32”, and the vertical wall 12 at the groove forming portion 30 is referred to as “groove vertical wall 33”. The flange 13 at the groove forming portion 30 is referred to as a “groove flange 34”.

The groove top plate 32 is located in the same plane as the top plate 11 in the portion other than the groove forming portion 30, and the groove flange 34 is located in the same plane as the flange 13 in the portion other than the groove forming portion 30. There is. As shown in FIG. 4, the groove vertical wall 33 of the first embodiment is recessed in a triangular shape when viewed from a direction perpendicular to the top plate 11. The groove vertical wall 33 has one ridge line 31a located at the bottom of the groove portion 31 and a pair of flat side surfaces 31b between the vertical wall 12 and the ridge line 31a in a portion other than the groove forming portion 30. That is, the groove portion 31 includes one ridge line 31a and two side surface 31b, and each of the two side surface 31b is connected to one ridge line 31a. In other words, the two side surfaces 31b are connected to each other via one ridge line 31a. The ridge line 31a extends in a direction (Z direction) perpendicular to the longitudinal direction (Y direction) of the hat member 10.

A plurality of groove forming portions 30 are provided at intervals along the member longitudinal direction of the hat member 10. That is, the two vertical walls 12 are provided with a plurality of groove portions 31 along the member longitudinal direction of the hat member 10. In the first embodiment, the region where the groove forming portion 30 exists is only the central portion in the member longitudinal direction of the hat member 10, but the groove forming portion 30 covers, for example, the entire area of the hat member 10 in the member longitudinal direction. It may be provided.

The automobile skeleton member 1 of the first embodiment is configured as described above. In the automobile skeleton member 1, a load is partially applied from the Z direction at the time of a collision. In the case of the automobile skeleton member 1 of the first embodiment, the groove portion 31 of the hat member 10 is not only between the vertical wall 12 but also between the ridge line portion 14 between the vertical wall 12 and the top plate 11 and between the vertical wall 12 and the flange 13. Since the ridge line portion 15 is also provided, the rigidity of the ridge line portion 15 is increased and the load required for deformation of the automobile skeleton member 1 is increased as compared with the case where the groove portions 31 are not provided in the ridge line portions 14 and 15. be able to. Further, since the groove portion 31 has a shape having one ridge line 31a extending in the direction perpendicular to the top plate 11 and two side surface 31b, the surface rigidity of the vertical wall 12 can be further increased, and the automobile skeleton member 1 can be formed. The load required for deformation can be further increased. In the automobile skeleton member 1 of the first embodiment, the energy absorption performance can be improved by their actions. Further, since the automobile skeleton member 1 of the first embodiment does not have a structure in which a reinforcing member is newly added, it is possible to improve the mass efficiency related to the energy absorption performance.

When the automobile skeleton member 1 is deformed, any of the following deformation modes occurs.

(Out-of-plane folding mode)
As shown in FIGS. 7 and 8, the out-of-plane bending mode is a mode in which the main deformation is a deformation in which the vertical wall 12 of the hat member 10 is bent in the out-of-plane direction in a cross section perpendicular to the longitudinal direction of the member.
(In-plane folding mode)
As shown in FIG. 9, in the in-plane folding mode, the main deformation is the deformation in which the vertical wall 12 of the hat member 10 bends in the longitudinal direction of the member, and in the out-of-plane direction in the cross section perpendicular to the longitudinal direction of the member. This is a mode in which the deformation of the vertical wall 12 is small.
(Axial crush mode)
As shown in FIGS. 10 and 11, the axial crushing mode is a mode in which the vertical walls 12 of the hat member 10 are crushed at short intervals in a cross section perpendicular to the longitudinal direction of the member, and a bellows-like deformation occurs as a whole.

In order to stably increase the load required for deformation from the initial stage of the collision to the latter stage of the collision, it is preferable that the automobile skeleton member 1 is deformed in the axial crushing mode.

Here, as shown in FIG. 4, the depth of the groove 31 in the cross section parallel to the top plate 11 of the hat member 10 is defined as “a”, the width of the groove 31 is defined as “b”, and the hat is defined as shown in FIG. The height of the vertical wall 12 in the direction perpendicular to the top plate 11 of the member 10 is defined as "e". The depth a of the groove portion 31 is the length from the vertical wall 12 to the ridge line 31a in the direction (X direction) perpendicular to the member longitudinal direction of the hat member 10 in the cross section parallel to the top plate 11. The width b of the groove portion 31 is the maximum length between the two side surfaces 31b in the member longitudinal direction (Y direction) of the hat member 10. The height e of the vertical wall 12 is the length from the flange 13 to the top plate 11 in the direction (Z direction) perpendicular to the member longitudinal direction of the hat member 10. In the first embodiment, the height e of the vertical wall 12 is equal to the height from the groove flange 34 to the groove top plate 32.

In order to make it easy for the automobile skeleton member 1 to be deformed in the axial crushing mode, the depth a of the groove portion 31, the width b of the groove portion 31, and the height e of the vertical wall 12 of the hat member 10 are 0.2. It is preferable that the relationship of ≦ a / e ≦ 0.3 and 0.1 ≦ b / e ≦ 0.3 is satisfied. When this numerical range is satisfied, the deformation of the automobile skeleton member 1 tends to be in the axial crushing mode as shown in the embodiment described later, and the load required for the deformation is stably increased from the early stage of the collision to the late stage of the collision. Thereby, the energy absorption performance can be further improved. From the viewpoint of further improving the energy absorption efficiency, b / e is preferably 0.2 or less.

Further, the distance c (FIG. 4) between the adjacent groove portions 31 is preferably 40 mm or less. When the distance c between the groove portions 31 is 40 mm or less, the shaft crushing mode is likely to be deformed, and the energy absorption efficiency can be improved. The smaller the distance c between the groove portions 31, the more the energy absorption efficiency can be improved. However, from the viewpoint of moldability of the hat member 10 having the groove portion 31, the distance c between the groove portions 31 is 10 mm or more. preferable. Further, in order to more easily induce the deformation of the axial crushing mode, the angle θ ₁ formed by the two side surfaces 31b is preferably 90 to 95 degrees, and more preferably vertical. Further, in order to more easily induce the deformation of the axial crushing mode, the angle θ ₂ formed by the groove vertical wall 33 and the groove flange 34 as shown in FIG. 6 is preferably 90 to 100 degrees, and is vertical. Is more preferable.

From the viewpoint of making it easier to induce deformation in the axial crushing mode, the radius of curvature d of the ridge line 31a shown in FIG. 12 (radius of curvature of the ridge line R) is preferably 5 mm or less.

<Second embodiment>
As shown in FIGS. 13 and 14, in the automobile skeleton member 1 of the second embodiment, the groove portion 31 does not extend to the ridgeline portion 14 of the hat member 10. More specifically, in the automobile skeleton member 1 of the second embodiment, although one end of the groove 31 extends to the inner end of the vertical wall 12 (the ridge line 15 in the example of FIG. 15), the groove 31 The other end does not extend to the outer end of the vertical wall 12 (the ridge 14 in the example of FIG. 15). Even in the groove portion 31 having such a shape, the depth a of the groove portion 31, the width b of the groove portion 31, and the height e of the vertical wall 12 of the hat member 10 are 0.2 ≦ a / e ≦ 0. By satisfying the relationship of 3 and 0.1 ≦ b / e ≦ 0.3, the shaft crushing mode is likely to be deformed, and the energy absorption efficiency can be improved. Also in this embodiment, b / e is preferably 0.2 or less from the viewpoint of further improving the energy absorption efficiency.

FIG. 15 is a diagram showing a shape example of the groove portion 31. In the automobile skeleton member 1 in the example of FIG. 15, unlike the example of FIG. 14, one end of the groove portion 31 extends to the vehicle outer end portion of the vertical wall 12 (the ridge line portion 14 in the example of FIG. 15), while the groove portion The other end of 31 has a structure that does not extend to the inner end portion of the vertical wall 12 (the ridgeline portion 15 in the example of FIG. 15). Even with such a structure, the energy absorption efficiency can be improved as shown in FIG.

However, the automobile skeleton member 1 having the structure shown in FIG. 14 can improve the energy absorption efficiency as compared with the automobile skeleton member 1 having the structure shown in FIG. When an impact load is input to the automobile skeleton member 1, the buckling region expands from the first buckled portion of the vertical wall 12 toward the inner end of the vertical wall 12. Therefore, it is advantageous in terms of improving the energy absorption efficiency that the first buckling point is on the outside of the vehicle of the vertical wall 12. The reason is that if the inside of the vertical wall 12 buckles first, the deviation between the extending direction of the groove 31 on the outside of the vehicle and the impact input direction becomes large, and the shaft crushing mode is less likely to be deformed, resulting in a bellows-like deformation region. Because it becomes smaller. That is, it is desirable that the groove portion 31 extends to the inner end portion of the vertical wall 12 on the vehicle side. The first place to buckle is the place without the groove 31. The reason for first buckling without the groove 31 is that the deformation resistance is small without the groove 31.

In the case of the automobile skeleton member 1 of FIG. 14, the groove portion 31 extends to the vehicle inner end portion (ridge line portion 15 in the example of FIG. 14) of the vertical wall 12 and the vehicle outer end portion of the vertical wall 12 (in the example of FIG. 14). The groove portion 31 is not formed in the ridge line portion 14). Therefore, the automobile skeleton member 1 of FIG. 14 tends to buckle in the vicinity of the vehicle outer end portion (ridge line portion 14 in the example of FIG. 14) of the vertical wall 12 when an impact load is input. On the other hand, the automobile skeleton member 1 of FIG. 15 tends to buckle in the vicinity of the vehicle inner end portion (ridge line portion 15 in the example of FIG. 15) of the vertical wall 12. Therefore, the automobile skeleton member 1 having the structure shown in FIG. 14 can secure a large area of deformation in a bellows shape as compared with the automobile skeleton member 1 having the structure shown in FIG. 15, and can improve the energy absorption efficiency. Can be done.

Further, according to the automobile skeleton member 1 of the second embodiment, since the groove portion 31 is not formed in one of the ridge line portions 14 and the ridge line portions 15, the automobile of the first embodiment. Compared to the skeleton member 1, the hat member 10 is easier to mold. That is, the automobile skeleton member 1 of the second embodiment is a member capable of achieving both energy absorption efficiency and moldability at a high level.

When the groove portion 31 extends to the vehicle inner end portion (ridge line portion 15 in the example of FIG. 14) of the hat member 10 as shown in FIG. 14, the length g of the groove portion 31 in the direction perpendicular to the top plate 11 of the hat member 10. Is preferably a length of 80% or more of the height e of the vertical wall 12 of the hat member 10. As a result, the shaft crushing mode is likely to be deformed when the impact load is input, and the energy absorption efficiency can be improved. The length g of the groove portion 31 when the groove portion 31 extends to the inner end portion of the hat member 10 is the R stop on the ridge line portion 14 side of the vertical wall 12 and the groove portion 31 side at the groove forming portion 30. Of the R stops, it is the length in the Z direction from the R stop on the groove 31 side to the flange 13. When the groove portion 31 extends to the vehicle inner end of the hat member 10, the length g of the groove portion 31 is 90% or more of the height e of the vertical wall 12 from the viewpoint of further improving the energy absorption efficiency. It is more preferable to have a length of 95% or more.

Further, when the groove portion 31 does not extend to the vehicle inner end portion (ridge line portion 15 in the example of FIG. 14) of the hat member 10 as shown in FIG. 15, the length of the groove portion 31 in the direction perpendicular to the top plate 11 of the hat member 10 The length g is preferably 70% or more of the height e of the vertical wall 12 of the hat member 10. As a result, the shaft crushing mode is likely to be deformed when the impact load is input, and the energy absorption efficiency can be improved. The length g of the groove portion 31 when the groove portion 31 does not extend to the inner end portion of the hat member 10 is the R stop on the ridge line portion 15 side of the vertical wall 12 and the groove portion 31 side at the groove forming portion 30. Of the R stops, it is the length in the Z direction from the R stop on the groove 31 side to the top plate 11. When the groove portion 31 does not extend to the vehicle inner end of the hat member 10, the length g of the groove portion 31 is 75% or more of the height e of the vertical wall 12 from the viewpoint of further improving the energy absorption efficiency. More preferably, it is more preferably 85% or more or 90% or more in length.

<Third embodiment>
In the automobile skeleton member 1 in the first embodiment, the mating member of the hat member 10 was the closing plate 20. In the automobile skeleton member 1 of the third embodiment shown in FIG. 16, the mating member is also a hat member. In the following description, the hat member (upper member in FIG. 16) described in the first embodiment is referred to as a "first hat member 10a", and a hat member (a hat member serving as a mating member of the first hat member 10a). The lower member in FIG. 16) is referred to as a "second hat member 10b". Like the first hat member 10a, the second hat member 10b also has a top plate 11, a pair of vertical walls 12 connected to the top plate 11, and a flange 13 connected to the vertical wall 12. The automobile skeleton member 1 is configured by joining the first hat member 10a and the second hat member 10b with each other flange 13. Also in the automobile skeleton member 1 of the third embodiment, the groove portion 31 of the first hat member 10a has one ridge line 31a and two side surfaces 31b when viewed from a direction perpendicular to the top plate 11 as shown in FIG. The groove portion 31 is provided from the ridge line portion 14 to the ridge line portion 15 as shown in FIG. Therefore, the energy absorption efficiency can be improved.

Further, as shown in FIG. 17, the second hat member 10b may also be provided with the groove portion 31 in the same manner as the first hat member 10a. As a result, the energy absorption efficiency can be further improved. In the case where the groove 31 is provided in the second hat member 10b, and the depth a of the groove 31, the sum of the height e ₂ of the height of the first hat member 10a e ₁ and the second hat member 10b e the ratio of the (a / e) is 0.2 to 0.3, and the width b of the groove 31, the height of the height of the first hat member 10a e ₁ and the second hat member 10b e ₂ The ratio (b / e) of to the sum e is preferably 0.1 to 0.3. Also in this embodiment, b / e is preferably 0.2 or less from the viewpoint of further improving the energy absorption efficiency. _{Further, the angle θ 1} formed by the two side surfaces 31b of the groove portion 31 is preferably 90 to 95 degrees, and more preferably vertical. _{Further, the angle θ 2} formed by the groove vertical wall 33 and the groove flange 34 is preferably 90 to 100 degrees, and more preferably vertical.

Furthermore, both the first hat member and the second hat member 10b may have a groove forming portion 30, the height e ₂ of the second hat member 10b of the height e ₁ of the first hat member 10a The ratio (e ₂ / e ₁ ) is preferably 0.25 or less. When this numerical range is satisfied, the deformation of the axial crushing mode is more likely to be induced, and the energy absorption efficiency can be improved as compared with the case where _{e 2} / e _{1 exceeds 0.25.} e ₂ / e ₁ is more preferably 0.2 or less, and further preferably 0.1 or less. That _{is, the smaller e 2} / e ₁ , the more preferable.

<Fourth Embodiment>
The automobile skeleton member 1 of the first to third embodiments described above is configured by joining a plurality of members to each other, whereas the automobile skeleton member 1 of the fourth embodiment is shown in FIGS. 18 and 19. As shown in, it is composed of a square tubular hollow member 2. The hollow member 2 has a top plate 11, two vertical walls 12 connected to the top plate 11, and a bottom plate 16 connected to the two vertical walls 12. The two vertical walls 12 are between the top plate 11 and the bottom plate 16, respectively, and the two vertical walls 12 face each other. The top plate 11 and the bottom plate 16 also face each other. The material of the hollow member 2 is not particularly limited, and is, for example, a steel material, an aluminum alloy member, a magnesium alloy member, or the like. When the automobile skeleton member 1 of the fourth embodiment is, for example, a member constituting the side sill 41 of the electric vehicle 40, the bottom plate 16 of the hollow member 2 is a floor panel (not shown) as in the example of FIG. Adjacent to the battery 42 located below.

Similar to the first to third embodiments, the automobile skeleton member 1 of the fourth embodiment has a plurality of groove portions 31 extending in a direction perpendicular to the member longitudinal direction of the hollow member 2. From the viewpoint of effectively improving the energy absorption efficiency, the groove portion 31 is formed so as to extend from the ridge line portion 14 to the ridge line portion 17, that is, from the vehicle outer end portion to the vehicle inner end portion of the vertical wall 12. Is preferable. Grooves 31 are provided on both of the pair of vertical walls 12. The molding method of the groove portion 31 is not particularly limited. For example, after forming a square tubular hollow member by extrusion molding, press working is repeated to gradually increase the depth of the groove portion 31 to perform molding. Be struck. Further, for example, the groove portion 31 may be formed by hydroforming.

A plurality of groove forming portions 30 are provided along the member longitudinal direction of the hollow member 2. That is, the two vertical walls 12 are provided with a plurality of groove portions 31 along the member longitudinal direction of the hollow member 2. In the present specification, the top plate 11 at the groove forming portion 30 is referred to as "groove top plate 32", the vertical wall 12 at the groove forming portion 30 is referred to as "groove vertical wall 33", and the bottom plate 16 at the groove forming portion 30 is referred to as "groove vertical wall 33". It is called the groove bottom plate 35 ". The groove top plate 32 is located in the same plane as the top plate 11 in the portion other than the groove forming portion 30, and the groove bottom plate 35 is located in the same plane as the bottom plate 16 in the portion other than the groove forming portion 30. There is. The shape of the groove 31 in a plan view is the same as that of the first to third embodiments. That is, in the automobile skeleton member 1 of the fourth embodiment as in the case of FIG. 4, the groove portion 31 extends in the direction (Z direction) perpendicular to the longitudinal direction of the hat member 10 on the groove portion vertical wall 33. There is one ridge line 31a located at the bottom, and a side surface 31b which is a pair of planes between the vertical wall 12 and the ridge line 31a in a portion other than the groove forming portion 30. That is, the groove portion 31 includes one ridge line 31a and two side surface 31b, and each of the two side surface 31b is connected to one ridge line 31a. In other words, the two side surfaces 31b are connected to each other via one ridge line 31a.

The automobile skeleton member 1 of the fourth embodiment is configured as described above. Also in the automobile skeleton member 1 of the fourth embodiment, the depth a of the groove portion 31 (FIG. 4), the width b of the groove portion 31 (FIG. 4), and the height e of the vertical wall 12 of the hollow member 2 (FIG. 19). ) Satisfies the relationship of 0.2 ≦ a / e ≦ 0.3 and 0.1 ≦ b / e ≦ 0.3. Therefore, the energy absorption efficiency can be improved as in the automobile skeleton member 1 of the first to third embodiments. Also in this embodiment, b / e is preferably 0.2 or less from the viewpoint of further improving the energy absorption efficiency. The height e of the vertical wall 12 of the hollow member 2 is the length from the bottom plate 16 to the top plate 11 in the direction (Z direction) perpendicular to the longitudinal direction of the member. Further, the height e of the vertical wall 12 of the hollow member 2 of the fourth embodiment is equal to the height from the groove bottom plate 35 to the groove top plate 32.

The distance c (FIG. 4) between the adjacent groove portions 31 is preferably 40 mm or less as in the first to third embodiments. As a result, the shaft crushing mode is likely to be deformed, and the energy absorption efficiency can be improved. From the viewpoint of moldability of the hollow member 2 having the groove portion 31, the distance c between the groove portions 31 is preferably 10 mm or more. Further, in order to more easily induce the deformation of the axial crushing mode, the angle θ ₁ (FIG. 4) formed by the two side surfaces 31b of the groove portion 31 is preferably 90 to 95 degrees, and is preferably vertical. More preferred. Further, in order to more easily induce the deformation of the axial crushing mode, the angle θ ₃ formed by the groove vertical wall 33 and the groove bottom plate 35 is preferably 80 to 90 degrees as shown in FIG. 19, and is vertical. Is more preferable.

Similar to the case of the second embodiment shown in FIG. 13, even when the automobile skeleton member 1 is composed of the hollow member 2, the groove portion 31 is the vehicle inner end portion of the vertical wall 12 (as shown in FIG. 20). In the example of FIG. 20, it does not have to be formed over the entire area from the ridge line portion 17) to the outer end portion of the vehicle (ridge line portion 14 in the example of FIG. 20). When the groove portion 31 is formed up to the inner end portion of the vehicle as shown in FIG. 20, the length g of the groove portion 31 in the direction perpendicular to the top plate 11 of the hollow member 2 is the height of the vertical wall 12 of the hollow member 2. It is preferably 80% or more of the length of e. This makes it possible to achieve both energy absorption efficiency and moldability at a high level. From the viewpoint of further improving the energy absorption efficiency, the length g of the groove portion 31 is more preferably 90% or more of the height e of the vertical wall 12, and further preferably 95% or more. preferable. The length g of the groove portion 31 when the groove portion 31 extends to the inner end of the vehicle is the R stop on the ridge line portion 14 side of the vertical wall 12 and the R stop on the groove portion 31 side at the groove forming portion 30. It is the length in the Z direction from the R stop on the groove 31 side to the bottom plate 16.

Further, as shown in FIG. 21, when the automobile skeleton member 1 is composed of the hollow member 2, the groove portion 31 is not formed up to the vehicle inner end portion (the ridge line portion 17 in the example of FIG. 21). The length g of the groove 31 in the direction perpendicular to the top plate 11 of the hollow member 2 is preferably 70% or more of the height e of the vertical wall 12 of the hollow member 2. This makes it possible to achieve both energy absorption efficiency and moldability at a high level. From the viewpoint of further improving the energy absorption efficiency, the length g of the groove portion 31 is more preferably 80% or more of the height e of the vertical wall 12, and is 85% or more or 90% or more. It is more preferable to have. The length g of the groove portion 31 when the groove portion 31 does not extend to the inner end of the vehicle is the R stop on the ridge line portion 17 side of the vertical wall 12 and the R stop on the groove 31 side at the groove forming portion 30. It is the length in the Z direction from the R stop on the groove 31 side to the top plate 11.

Further, even when the automobile skeleton member 1 is composed of the hollow member 2, from the viewpoint of making it easier to induce the deformation of the axial crushing mode, the radius of curvature d of the ridge line 31a shown in FIG. 12 (the radius of curvature of the ridge line R). ) Is preferably 5 mm or less.

Although one embodiment of the present invention has been described above, the present invention is not limited to such an example. 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 above embodiment, the shape of the groove 31 with respect to the vertical wall 12 is concave, but it may be convex as shown in FIG. 22 or FIG. 23. In the case of the automobile skeleton member 1 of FIG. 22 or 23, at the groove forming portion 30, the inner surface of the vertical wall 12 is recessed toward the outside of the vertical wall 12, and becomes a groove portion 31 having one ridge line and two side surfaces. ing. Even in such an automobile skeleton member 1, the depth a of the groove portion 31, the width b of the groove portion 31, and the height e of the vertical wall 12 are 0.2 ≦ a / e ≦ 0.3, and If the relationship of 0.1 ≦ b / e ≦ 0.3 is satisfied, the shaft crushing mode is likely to be deformed, and the energy absorption efficiency can be improved. Further, even in the case of the convex groove portion 31, b / e is preferably 0.2 or less from the viewpoint of further improving the energy absorption efficiency as in the above-described embodiment. Further, the length g of the groove portion 31 is preferably 80% or more of the height e of the vertical wall 12. Further, the distance c between the groove portions 31 is preferably 40 mm or less. Further, the radius of curvature d of the ridge line 31a (radius of curvature of the ridge line R) is preferably 5 mm or less.

<Simulation (1)>
As an example of the automobile skeleton member according to the present invention, an analysis model (example structure) as shown in FIG. 24 was created, and a simulation simulating a pole side collision was carried out. The analysis model of FIG. 24 has a configuration equivalent to that of the automobile skeleton member shown in FIG. 1, and is composed of a hat member 10 and a closing plate 20. The material of the hat member 10 and the closing plate 20 is a steel material having a tensile strength of 1180 MPa and a plate thickness of 1.6 mm. A plurality of groove forming portions 30 are provided at the central portion of the hat member 10 in the longitudinal direction of the member. The total length of the hat member 10 is 1500 mm, and the height e (length in the Z direction) of the vertical wall 12 and the width (length in the X direction) of the top plate 11 are 100 mm, respectively. The depth a and the width b of the groove portion 31 are 20 mm each. That is, the above-mentioned values of a / e and b / e are 0.2, respectively. The groove c is 20 mm.

The simulation is carried out by pressing a columnar impactor 50 having a radius of 127 mm against the top plate 11 and displacing the impactor 50 at a speed of 1.8 km / h. In this simulation, a rigid wall is arranged on the top plate 11. Further, as a comparative example, an analysis model (comparative example structure) having no groove in the hat member was created, and the same simulation as the above conditions was carried out. The simulation result (1) is shown in FIG.

As shown in FIG. 25, the absorbed energy (EA) of the Example structure was significantly improved as compared with the Comparative Example structure.

<Simulation (2)>
Next, as shown in FIG. 26, the ratio of the groove depth a (FIG. 4) to the vertical wall height e (FIG. 6), and the groove width b (FIG. 4) and the vertical wall height e (FIG. 6). A plurality of analysis models having different ratios of 6) were created, and simulations were carried out with each analysis model. FIG. 26 also shows the deformation modes of each analysis model generated in the simulation. The simulation conditions are the same as those in the simulation (1) except that the analysis model is different.

As shown in FIG. 26, in the analysis model in which a / e is 0.2 to 0.3 and b / e is 0.1 to 0.3, the axial crushing mode is deformed. Next, the relationship between a / e, b / e, and energy absorption efficiency (EA efficiency) is summarized in Table 1 below.

As shown by the results of FIG. 26 and Table 1, the model in which the shaft crushing mode is deformed has improved energy absorption efficiency as compared with the model in which the shaft crushing mode is not deformed. For example, comparing the model of "a / e = 0.1, b / e = 0.1" with the model of "a / e = 0.2 to 0.3, b / e = 0.1", the axes The energy absorption efficiency is improved in the model of "a / e = 0.2 to 0.3, b / e = 0.1" in which the deformation of the crushing mode occurs. Similarly, even in the case of "b / e = 0.2", the energy efficiency of the model of "a / e = 0.2 to 0.3" is higher than that of the model of "a / e = 0.1". It is improving. Similarly, even in the case of "b / e = 0.3", the energy absorption efficiency of the model of "a / e = 0.2 to 0.3" is higher than that of the model of "a / e = 0.1". Is improving. According to the result of this simulation, in the automobile skeleton member 1 in which a / e is 0.2 to 0.3 and b / e satisfies 0.1 to 0.3, the deformation of the shaft crushing mode Is more likely to occur, and energy absorption efficiency is improved.

Further, as shown in Table 1, the energy absorption efficiency becomes even higher when a / e is 0.2 to 0.3 and b / e is 0.1 to 0.2. Therefore, b / e is preferably 0.2 or less. When b / e was 0.1 or less, the deformation of the axial crushing mode and the deformation of the in-plane folding mode occurred at the same time, and the energy absorption efficiency became the highest. The reason why the axial crushing mode and the in-plane bending mode occur together is that the shape of the groove is such that two side surfaces are connected to one ridgeline, so that the distance between the two side surfaces is close to each other near the ridgeline. It is considered that when the width b of the groove portion is narrow, the two side surfaces are likely to come into contact with each other.

<Simulation (3)>
Next, in the structure in which the groove portion 31 extends to the inner end portion of the vehicle (the ridgeline portion 15 in the example of FIG. 14) as shown in FIG. 14, the ratio of the length g of the groove portion and the height e of the vertical wall is different. Multiple models were created and simulations were performed with each analysis model. The simulation conditions are the same as those in the simulation (1) except that the analysis model is different. The results of simulation (3) are shown in Table 2 below.

As shown in Table 2, when g / e is 0.8 or more, the energy absorption efficiency is dramatically improved as compared with the case where g / e is less than 0.8. Under the conditions of this simulation, when g / e was 0.8 to 1.0, the automobile skeleton member was deformed in the axial crushing mode. That is, when the groove portion 31 extends to the inner end portion of the vehicle (the ridge line portion 15 in the example of FIG. 14), the length g of the groove portion is preferably 80% or more of the height e of the vertical wall. ..

<Simulation (4)>
Next, in a structure in which the groove portion 31 does not extend to the inner end of the vehicle (the ridgeline portion 15 in the example of FIG. 15) as shown in FIG. 15, the ratio of the length g of the groove portion and the height e of the vertical wall is different. Multiple models were created and simulations were performed with each analysis model. The simulation conditions are the same as the conditions of simulation (1) except that the analysis model is different. The results of simulation (4) are shown in Table 3 below.

As shown in Table 3, when g / e is 0.7 or more, the energy absorption efficiency is dramatically improved as compared with the case where g / e is less than 0.7. Under the conditions of this simulation, when g / e was 0.7 to 1.0, the automobile skeleton member was deformed in the axial crushing mode. That is, when the groove portion 31 does not extend to the inner end portion of the vehicle (the ridgeline portion 15 in the example of FIG. 15), the length g of the groove portion is preferably 70% or more of the height e of the vertical wall. ..

<Simulation (5)>
Next, a plurality of analysis models having different groove spacings c (FIG. 4) were created, and simulations were performed with each analysis model. The simulation conditions are the same as those in the simulation (1) except that the analysis model is different. The results of simulation (5) are shown in Table 4 below.

As shown in Table 4, under the conditions of this simulation, when the groove c is 40 mm or less, the shaft crushing mode is deformed and the energy absorption efficiency is improved.

<Simulation (6)>
Next, a plurality of analysis models having different radii of curvature d (FIG. 12) of the ridge line R of the groove were created, and simulation was performed with each analysis model. The simulation conditions are the same as those in the simulation (1) except that the analysis model is different. The results of simulation (6) are shown in Table 5 below.

As shown in Table 5, under the conditions of this simulation, when the radius of curvature d of the ridge line R of the groove is 5 mm or less, the axial crushing mode is deformed and the energy absorption efficiency is improved.

The technique according to the present invention can be used for a side sill, a bumper beam, or the like of an automobile.

1 Automobile skeleton member 2 Hollow member 10 Hat member 10a First hat member 10b Second hat member 11 Top plate 12 Vertical wall 13 Flange 14 Ridge line part 15 Ridge line part 16 Bottom plate 17 Ridge line part 20 Closing plate 30 Groove forming part 31 Groove part 31a Groove ridge 31b Groove side surface 32 Groove top plate 33 Groove vertical wall 34 Groove flange 35 Groove bottom plate 40 Electric vehicle 41 Side sill 42 Battery 50 Impactor a Groove depth b Groove width c Groove spacing d Ridge radius e Vertical wall height g Groove length θ _{1 Angle between the two} sides of the groove θ 2 Angle between the groove vertical wall and the groove flange θ ₃ Angle between the groove vertical wall and the groove bottom plate

Claims (12)

Equipped with a hat member and a closing plate
The hat member includes a top plate, two vertical walls, and two flanges.
The two vertical walls are located between the top plate and the flange, respectively.
The two vertical walls face each other
The two flanges are each joined to the closing plate and
Each of the two vertical walls has a plurality of grooves extending in a direction perpendicular to the longitudinal direction of the hat member.
The groove has one ridge and two sides.
The ridge extends in a direction perpendicular to the longitudinal direction of the hat member.
The two sides are connected to the ridgeline, respectively.
The depth a of the groove in the cross section parallel to the top plate, the width b of the groove, and the height e of the vertical wall in the direction perpendicular to the top plate are 0.2 ≦ a / e ≦ 0. An automobile skeleton member that satisfies the relationship of 3 and 0.1 ≦ b / e ≦ 0.3. The groove extends to the inner end of the vertical wall.
The automobile skeleton member according to claim 1, wherein the length g of the groove portion in the direction perpendicular to the top plate is 80% or more of the height e of the vertical wall. The groove does not extend to the inner end of the vertical wall,
The automobile skeleton member according to claim 1, wherein the length g of the groove portion in the direction perpendicular to the top plate is 70% or more of the height e of the vertical wall. The automobile skeleton member according to any one of claims 1 to 3, wherein the groove c is 40 mm or less. The automobile skeleton member according to any one of claims 1 to 4, wherein the radius of curvature d of the ridge line is 5 mm or less. Equipped with hollow members
The hollow member includes a top plate, a bottom plate, and two vertical walls.
The top plate and the bottom plate face each other,
The two vertical walls are located between the top plate and the bottom plate, respectively.
The two vertical walls face each other
Each of the two vertical walls has a plurality of grooves extending in a direction perpendicular to the longitudinal direction of the hollow member.
The groove has one ridge and two sides.
The ridge extends in a direction perpendicular to the longitudinal direction of the hollow member.
The two sides are connected to the ridgeline, respectively.
The depth a of the groove in the cross section parallel to the top plate, the width b of the groove, and the height e of the vertical wall in the direction perpendicular to the top plate are 0.2 ≦ a / e ≦ 0. An automobile skeleton member that satisfies the relationship of 3 and 0.1 ≦ b / e ≦ 0.3. The groove extends to the inner end of the vertical wall.
The automobile skeleton member according to claim 6, wherein the length g of the groove portion in the direction perpendicular to the top plate is 80% or more of the height e of the vertical wall. The groove does not extend to the inner end of the vertical wall,
The automobile skeleton member according to claim 6, wherein the length g of the groove portion in the direction perpendicular to the top plate is 70% or more of the height e of the vertical wall. The automobile skeleton member according to any one of claims 6 to 8, wherein the groove c is 40 mm or less. The automobile skeleton member according to any one of claims 6 to 8, wherein the radius of curvature d of the ridge line is 5 mm or less. A side sill provided with the automobile skeleton member according to any one of claims 1 to 5, and a battery.
An electric vehicle in which the closing plate is adjacent to the battery and the top plate is arranged on the outside of the vehicle in a cross section perpendicular to the vehicle height direction. A side sill provided with the automobile skeleton member according to any one of claims 6 to 10 and a battery.
The bottom plate is adjacent to the battery in a cross section perpendicular to the vehicle height direction.
The top plate is an electric vehicle arranged on the outside of the vehicle.

Images