KR102558628B1 - Structural members for vehicles - Google Patents

Abstract

The crash resistance performance of the structural member is effectively improved while suppressing an unnecessarily increased mass of the structural member. The structural member includes a hollow member (1) and a tension member (12). The hollow member 1 has a closed cross-sectional shape with a top plate portion 10A, a pair of side wall portions 10B each successive on both sides of the top plate portion 10A in the width direction, and a bottom plate portion 11 arranged opposite to the top plate portion 10A. The tension member 12 is made of a metal plate that extends along the width direction of the top plate portion 10A and is thinner than the plate thickness of the hollow member, and connects the inner surfaces of the pair of side wall portions 10B that oppose each other to restrain an increase in the distance between the pair of side wall portions 10B.

Description

Structural members for vehicles

The present invention relates to a structural member (skeletal part) for automobiles comprising a top plate portion, a pair of side wall portions, and a bottom plate portion in a closed cross-sectional shape. In particular, the present invention is a technique for providing a structural member having crash resistance against bending deformation (deformation in the bending crushing direction) due to a crash load input from directions along opposite directions of the top plate portion and the bottom plate portion.

In recent years, in the field of automobiles, stricter crash safety standards are in progress from the viewpoint of protecting crew members, and there is a strong demand for expanding the application of high-strength steel and developing vehicles with excellent crash safety performance.

Here, as a form of collision, there are a form of collision in which axial crushing and a form of bending deformation occur. In an axial crushing collision type, axial crushing occurs when the longitudinal direction of a member coincides with the impact direction, such as a crash box or a front side member that receives a crash load input from the front of a vehicle. In the collision form of bending deformation (collision form of bending collapse), a collision load is applied to the side surface of a structural member, such as a B-pillar or side sill in a side collision, and the member bends and deforms. In both modes, collision resistance is exhibited by absorbing collision energy when the member buckles and deforms.

As one of the techniques for improving crash resistance, a technique for improving the surface rigidity of a structural member by attaching a reinforcing member to the surface of the member has been proposed. For example, Patent Literature 1 describes that a reinforcing member is placed in close contact with the inner surface of the bottom plate portion or top plate portion constituting the hollow member. Further, in Patent Literature 2, a reinforcing member joined to a ridge portion connecting a top plate portion and a side wall portion is provided, and a welded portion with the reinforcing member is formed at the ridge portion. Further, in Patent Document 3, it is described that collision energy absorption efficiency is improved in a steel plate member combination structure having a first steel plate member having a circumferential wall portion, an upright wall portion, and a flange portion, and a second steel plate member joined to the inner or outer surface of the ridge portion.

In addition, Patent Literature 4 proposes a shock absorbing member capable of reducing weight while ensuring energy absorption in the form of an axial crushing collision by providing a reinforcing member having a plurality of holes.

Japanese Unexamined Patent Publication No. 2017-159896 Japanese Unexamined Patent Publication No. 2014-87848 WO2017/030191 Japanese Unexamined Patent Publication No. 2016-155509

However, in the methods described in Patent Literatures 1 to 3, a reinforcing member is formed on the surface constituting the structural member to directly improve the surface rigidity. Further, in this prior art example, not much research has been done on the determination of the reinforcement position for efficiently improving the crash resistance performance.

Here, in the case of simply attaching a reinforcing member to the surface of the structural member, although the crash resistance performance is improved, the number of parts is increased, the mass of the structural member is increased more than necessary, or the mold is increased, so conventionally there is a problem in terms of cost. Particularly, in the prior art, the mass increase becomes remarkable as an attempt is made to reinforce a wide area with a reinforcing member.

Further, in Patent Literature 4, impact absorption in the axial direction in which mass increase is suppressed by forming a plurality of holes in a reinforcing member is studied, but collision in the bending crushing direction is not examined. In particular, Patent Document 4 stipulates that the plate thickness of the reinforcing member should be equal to or greater than the plate thickness of the hollow member in order to increase the absorbed energy by generating buckling deformation of a different phase during axial crushing deformation. However, it is not obvious whether this effect can be obtained in the same way for a collision in the bending crushing direction, and it is necessary to examine the optimal structure of the reinforcing member in bending crushing.

The present invention focuses on the above points, and aims to effectively improve the crash resistance performance of structural members against collisions in the bending and crushing direction while suppressing the unnecessarily increased mass of the structural members.

In order to solve the problem, one aspect of the present invention is a hollow member constituting a closed cross-sectional shape with a top plate portion, a pair of side wall portions each successive on both sides of the top plate portion in the width direction of the top plate portion, and a bottom plate portion disposed opposite to the top plate portion, and a metal plate extending along the width direction of the top plate portion and having a plate thickness smaller than that of the hollow member, and connecting the inner surfaces of the pair of opposing side wall portions to widen the distance between the pair of side wall portions. It is a summary to provide a tension member to restrain.

Further, another aspect of the present invention includes a top plate portion, a pair of side wall portions each successive on both sides of the top plate portion in the width direction, and a hollow member constituting a closed cross-sectional shape with a bottom plate portion disposed opposite to the top plate portion, and a tension member formed in the hollow member and made of a metal plate extending along the width direction of the top plate portion, wherein the top plate portion has one or two or more concave portions recessed toward the bottom portion along the width direction of the top plate portion; The gist of the tension member is to connect the inner surface of the side wall portion and the upright portion of the concave portion of the top plate portion opposed to the inner surface of the side wall portion in a state where there is a space between the inner surface of the top plate portion and the inner surface of the side wall portion.

According to the aspect of the present invention, since the tensile force of the tension member as the reinforcing plate suppresses the opening of the pair of side wall portions against a collision in the bending and crushing direction to improve the crash resistance performance, it is possible to effectively improve the crash resistance performance per member mass. That is, according to the aspect of the present invention, it is possible to suppress an excessive increase in the mass of the structural member by using the reinforcing plate as the tension member while effectively improving the crash resistance performance against the collision form of bending collapse.

1 is a perspective view showing a structural member according to an embodiment based on the present invention.
Fig. 2 is a cross-sectional view showing a structural member according to an embodiment based on the present invention.
Fig. 3 is a cross-sectional view showing another example of a structural member according to an embodiment based on the present invention.
Fig. 4 is a cross-sectional view showing an example of arrangement of tension members in the case where beads are formed in the top plate portion.
5 is a cross-sectional view showing an example of arrangement of tension members in the case where beads are formed in the top plate portion.
6 is a conceptual diagram illustrating a three-point bending crush test.
7 is a diagram explaining the behavior of member deformation by a three-point bending crush test, (a) shows a state at a deformation stroke amount: 20 mm, and (b) shows a state at a deformation stroke amount: 60 mm. In Fig. 7, the upper figure is a sectional view, and the lower figure is a side view.
Fig. 8 is a diagram showing an example of the relationship between a load and a deformation stroke amount.
Fig. 9 is a diagram showing the relationship between the reinforcement height ratio (y) and the maximum load per mass.
Fig. 10 is a diagram showing the relationship between the aspect ratio (x) and the reinforcement height ratio (y).

Next, an embodiment of the present invention will be described with reference to the drawings.

＜Configuration＞

As shown in FIGS. 1 and 2 , the structural member for a vehicle of the present embodiment includes a hollow member 1 and a tension member 12 reinforcing the hollow member 1 .

The hollow member 1 has a closed cross-sectional shape with a top plate portion 10A, a pair of side wall portions 10B each successive on both sides of the top plate portion 10A in the width direction, and a bottom plate portion 11 disposed opposite to the top plate portion 10A. As shown in FIGS. 1 and 2 , for example, the hollow member 1 of the present embodiment is composed of a top plate portion 10A and a pair of side wall portions 10B each successive on both sides of the top plate portion 10A in the width direction. In this example, the bottom plate portion 11 is disposed opposite to the top plate portion 10A, and both sides of the bottom plate portion 11 in the width direction are welded to the flange 10C formed at each end of the pair of side wall portions 10B.

In addition, one or two or more beads extending in the longitudinal direction may be formed in the top plate portion 10A or the bottom plate portion 11 . By forming the bead extending in the longitudinal direction, the structural member for a vehicle is improved in strength against load input in the bending crushing direction and also in strength against load input in the axial direction along the longitudinal direction of the hollow member 1.

The plate thickness and tensile strength of the hollow member 1 are set according to the specifications required for the site to be used. In this embodiment, the plate thickness of the hollow member 1 is 1.0 mm or more and 2.0 mm or less, for example. In addition, the tensile strength of the hollow member 1 is, for example, 440 MPa or more and 1470 MPa or less.

In addition, although the dimension of the member in an Example is written together in FIG. 1 and FIG. 2, this dimension does not limit this invention in any way.

The tension member 12 extends in the width direction of the top plate portion 10A, and is made of a metal plate whose plate thickness is smaller than that of the hollow member 1 . In addition, the material of the hollow member 1 and the tension member 12 may be the same or different.

In addition, the plate thickness and tensile strength of the tension member 12 are set according to the specifications required for the site to be used.

In this embodiment, the plate thickness of the tension member 12 is less than the plate thickness of the hollow member 1, 0.6 mm or more, and preferably 0.8 mm or less and 0.6 mm or more, for example. In addition, it is preferable to set the plate thickness of the tension member 12 to 50% or more and 80% or less of the plate thickness of the hat end face member 10, for example. Here, when the plate thickness of the tension member 12 is set to be less than the plate thickness of the hollow member 1, when the plate thicknesses of the respective parts 10 and 11 constituting the hollow member 1 are different, the hat end face member 10 or the bottom plate portion 11, the value of the thinner plate thickness is used.

Moreover, the tensile strength of the tension member 12 is 440 MPa or more and 1470 MPa or less, for example.

The tension member 12 is a reinforcing member that restrains the opening between the pair of side wall portions 10B by connecting the inner surfaces of the pair of side wall portions 10B facing each other. Since the tension member 12 suppresses the opening of the pair of side wall portions 10B with a tensile force against a collision in the bending and crushing direction, it is possible to reduce the plate thickness. The tension member 12 made of a metal plate is preferably parallel or approximately parallel to the surface of the top plate portion 10A, but the tension member 12 may be formed in a state inclined in the width direction or the longitudinal direction of the top plate portion 10A with respect to an imaginary plane parallel to the surface of the top plate portion 10A.

3 shows an example of a structural member for a vehicle in which the tension member 12 is formed in a state in which the tension member 12 is inclined toward the width direction of the top plate portion 10A with respect to an imaginary plane parallel to the surface of the top plate portion 10A. The vehicle structural member shown in FIG. 3 exemplifies a case where the heights of the pair of side wall portions 10B are different.

Further, the tension member 12 is arranged so as to form a space between the upper surface of the tension member 12 and the inner surface of the top plate portion 10A, and vertically partition the space between the top plate portion 10A and the bottom plate portion 11.

Both sides of the tension member 12 in the width direction are joined (connected) to the inner surface of the opposing side wall portion 10B by welding. 2 and 3, both ends of the tension member 12 in the width direction are bent to form the flange portion 12a, and the surface of the flange portion 12a is welded to the inner surface of the side wall portion 10B. It is an example in which the tension member 12 is attached. By welding the surface of the flange portion 12a to the inner surface of the side wall portion 10B, the tension member 12 is formed more firmly on the inner surface of the side wall portion 10B.

In the tension member 12, the bending radius (bending R) of the bending portion between the tension member 12 and the flange portion 12a formed at its end is preferably smaller so that a larger tensile force is obtained with respect to the opening of the pair of side wall portions 10B at the time of collision. In order to take moldability of the flange portion 12a into consideration and to make the radius of curvature of the bent portion smaller, the thickness of the tension member 12 is preferably thinner. Moreover, the one where the tensile strength of the tension member 12 is high is preferable. However, when setting the radius of curvature of the bent portion as small as, for example, 0.3 mm or less, in order to realize molding at the bent portion, depending on the sheet thickness of the tension member 12, it is necessary to set the tensile strength of the tension member 12 as low as, for example, 590 MPa or less. Here, the tension member 12 is mainly for bearing tension. That is, since the plate thickness of the tension member 12 does not contribute much to the tensile force, from the viewpoint of weight reduction, the plate thickness of the tension member 12 is preferably thinner. Therefore, even if the intensity|strength of the tension member 12 is reduced, it is preferable to make the said bending radius of curvature small.

Here, the tension member 12 need not be continuously formed over the entire surface of the hollow member 1 in the longitudinal direction. You may form the tension member 12 partially along the longitudinal direction of the hollow member 1. In this case, it is preferable to form the tension member 12 at a point including at least a position estimated to be highly likely to receive a collision load.

The surface position of the top plate portion 10A or the bottom plate portion 11, which is estimated to be highly likely to receive a crash load in the bending crushing direction, is estimated based on, for example, a vehicle position in which the structural member is disposed, based on past accident information, etc., depending on which part of the target structural member is likely to receive a crash load due to a side collision of the vehicle.

In addition, the specification of a deformation area|region is calculated|required by analyzing the deformation position of a member with respect to the impact load of a bending crushing direction by FEM simulation analysis, for example. As the preset crash load, an allowable crash load required as the crash resistance performance against the crash form in the bending and crushing direction at the position where the structural member is used is adopted.

Next, a suitable arrangement position (position in the height direction) of the tension member 12 made of a metal plate will be described.

Here, as shown in Fig. 2, the width of the closed cross-sectional shape formed on the inner surface of the hollow member 1 is w and the height is h. Moreover, the distance in the height direction from the top plate part 10A to the tension member 12 is made into the reinforcement position p.

The tension member is formed to bear a tensile force when the space between the opposing side wall portions 10B is to widen. For this reason, the reinforcement position p is a position to which the tension member 12 applies a tensile force when the space between the opposing side wall portions 10B is to be widened. That is, when the tension member 12 is a flat plate, the reinforcement position p is taken as a value at the center position of the tension member 12 in the thickness direction, for example. In addition, when the surface of the tension member 12 is disposed in an inclined state, the reinforcement position p is, for example, the center position of the tension member 12 or the center of gravity of the tension member 12 when viewed from a plane.

For example, the width w is the horizontal distance between the intersection of a straight line along the inner surface of the opposing side wall portion 10B and the upper surface of the bottom plate portion 11. Also, the height h is the vertical distance (opposite distance) between the top plate portion 10A and the bottom face portion.

Here, as shown in FIG. 3, when the top plate part 10A and the bottom plate part 11 are not parallel to each other, the height h is determined as follows. That is, as shown in FIG. 3 , the height h is the vertical distance between the bottom plate portion 11 and the neutral plane hm of the horizontal planes h1 and h2 of the R stop portions on the top plate portion 10A side of each ridge line at both ends of the top plate portion 10A in the width direction.

Further, as shown in FIG. 3 , the reinforcement position p in the case where the tension member 12 and the bottom plate portion 11 are not parallel is the vertical distance between the neutral plane pm of the horizontal planes p1 and p2 of the R stop portions p1 and p2 on the side of the tension member 12 of each ridge at both ends in the width direction of the tension member 12 and the neutral plane hm.

Further, the ratio (h/w) of the height (h) to the width (w) in the closed cross-sectional shape is referred to as the member aspect ratio (x). The ratio (p/h) of the reinforcement position (p) to the height (h) is described as the reinforcement height ratio (y).

At this time, it is preferable to set the height position of the tension member 12 so that the following formula (1) is satisfied (see Examples).

(1) By satisfying the equation, it is possible to improve the crash resistance performance more efficiently.

y ≤ 0.2x + 0.6... (One)

In addition, it is more preferable to form the tension member 12 in the range satisfying the equation (2) for further improvement of the crash resistance performance.

y ≤ 0.2x + 0.4... (2)

More preferably, it is preferable to satisfy the following formulas (3) and (4).

y ≤ 0.2x + 0.25 . (3)

y ≥ 0.2x ‥‥ (4)

4 and 5 , when a bead extending in the longitudinal direction is formed on the top plate portion 10A and one or two or more concave portions 10Ab are formed along the width direction in the top plate portion 10A, the height h is the vertical distance between the bottom plate portion 11 and the portion 10Aa of the top plate portion 10A other than the concave portion 10Ab. do In FIG. 4 and FIG. 5, the case where there is one concave part 10Ab in the width direction center part of top-plate part 10A is illustrated as an example.

In addition, when forming the tension member 12 in a structural member in which one or two or more concave portions 10Ab are formed in the top plate portion 10A along the width direction, a case in which the tension member 12 is disposed closer to the top plate portion 10A to less than the depth of the concave portion 10Ab will be described. That is, the case where the tension member 12 is formed so that reinforcement position p < the depth of a recess is demonstrated.

In this case, for example, as shown in FIG. 4 , the portion of the tension member 12 vertically opposed to the bottom of the concave portion 10Ab is deformed into a shape along the lower surface of the bottom portion of the concave portion 10Ab, whereby the reinforcement position p < the depth of the concave portion. The tension member 12 is disposed. In this case, the tension member 12 is attached to the inner surface of each side wall portion 10B by welding. You may fix by welding or adhesive also about the contact part of the tension member 12 and a bottom part.

Alternatively, as shown in FIG. 5 , the tension member 12 is disposed so as to connect the inner surface of the side wall portion 10B and the inner surface of the upright portion 10Ab1 of the concave portion 10Ab opposed to the inner surface of the side wall portion 10B with a space between the inner surface and the inner surface of the top plate portion 10A. In the case of FIG. 5 , two tension members 12 are disposed along the width direction of the top plate portion 10A.

In addition, in FIG. 4 and FIG. 5, although the case where one recessed part 10Ab is illustrated, two or more recessed parts may be formed.

<Movement and others>

The inventor, by FEM analysis, analyzed in detail the behavior of member deformation in the three-point bending crush test for a structural member (hollow member 1, without tension member 12) constituting a closed cross section with a hat end face member 10 having dimensions as shown in FIGS. 1 and 2 and a bottom plate portion 11. As shown in FIG. 6, the three-point bending analysis condition is a condition in which two points on the lower surface of the structural member separated in the longitudinal direction are supported by the supporting member 20, and a load is applied from the top to the bottom by a punch to the central portion in the longitudinal direction of the top plate portion 10A.

As shown in FIG. 7 showing the cross-sectional shape of the center of the member, the behavior of member deformation by the three-point bending crush test is as the stroke amount of the punch increases, FIG. 7 (a) → FIG. 7 (b), the member deforms downward while the left and right side wall portions 10B open outward. As a result of this deformation, the longitudinal center portion (load input position) of the member was bent in a V shape. 8 shows the relationship between the load and the deformation stroke amount (the amount of downward deformation at the load input position). As shown in FIG. 8 , the load decreases from the vicinity where the structural member begins to bend in a V shape with respect to the load in the bending crushing direction. And the inventors obtained the knowledge that it is effective to suppress the opening of the side wall part 10B which opposes, in order to increase the maximum load, when the maximum load of a load is made into crash resistance performance.

In the present embodiment, by connecting the opposing side wall portions 10B with the tension member 12, the collision resistance performance is improved by suppressing an increase in the distance between the opposing side wall portions 10B when the member is deformed, for example, due to a collision in which a load is input to the top plate portion.

That is, in the present embodiment, by forming the tension member 12 as described above, it is possible to improve the crash resistance performance of the structural member, particularly in the form of bending and deformation. The tension member 12 of the present embodiment restrains, by tension (tensile force), the displacement of a pair of side wall portions 10B facing each other in the width direction in the direction in which they are separated. As a result, in response to an input of a collision load to the top plate portion 10A or the bottom plate portion 11, swelling (buckling) of the pair of opposing side wall portions 10B in the out-of-plane direction is suppressed. That is, by forming the tension member 12 based on the present embodiment, it becomes possible to effectively suppress the cross-sectional deformation of the member at the time of collision, and to improve the maximum load in bending deformation in particular.

Further, since the tension member 12 made of a metal plate bears a tensile force against a collision load and does not necessarily need to bear a compressive force, it is also effective as a thin metal plate. That is, even if the tension member 12 is provided in order to improve the crash resistance performance, it is possible to suppress the increase in load compared to the prior art. That is, even if it forms the tension member 12 which consists of a metal plate as a reinforcing member, the mass increase accompanying it can be suppressed small.

Moreover, as can be seen from FIG. 7 , the position at which the side wall portion 10B deforms (swells) the most outward is the position on the top plate portion 10A side rather than the center portion in the height direction of the side wall portion 10B. For this reason, it is preferable to form the position where the tension member 12 is formed closer to the top plate portion 10A side than to the bottom plate portion 11 side with respect to the collision form of bending crushing.

More preferably, it is a position that satisfies the above expression (1). In this case, by forming the tension member 12 at an appropriate position according to the aspect ratio of the structural member, it becomes possible to provide a vehicle structural member with effectively improved crash resistance performance per member mass (see Examples). That is, the tension member 12 can be formed at an effective reinforcing position that differs for each aspect ratio of the structural member, and in the present embodiment, the crash resistance performance can be improved more effectively by specifying the reinforcing position.

Example

Next, examples based on the present invention will be described.

FEM analysis of member deformation in the three-point bending crush test was performed under the following conditions, and the improvement of the crash resistance performance by forming the tension member 12 was studied.

The structural member for a vehicle in the example had the configuration shown in FIGS. 1 and 2 .

The strength and plate thickness of the hat end face member 10, the bottom plate portion 11, and the tension member 12 constituting the hollow member 1 were set as shown in Table 1. In addition, the unit of strength is [MPa]. In addition, bending R of the bending part of the flange part 12a of the tension member 12 was 0.3 mm.

In addition, for each Example and Comparative Example, analysis was performed by setting to the specifications shown in Table 2. In Table 2, the maximum load per mass of the structural member at that time was also written.

In addition, the ratio (p/h) of the reinforcement position (p) to the height (h) was defined as the reinforcement height ratio (y) on the horizontal axis, and the maximum load per mass of the structural member was defined on the vertical axis. The result is shown in FIG. 9 .

In Example 5, the maximum load per mass is equal to that of Comparative Example 1, but the absolute value of the maximum load in Example 5 is greater than that of Comparative Example 1.

In addition, analysis was performed by changing the aspect ratio of the hollow member 1. The results are shown in Table 3.

Then, when the aspect ratio (x) was arranged along the horizontal axis and the reinforcement height ratio (y) along the vertical axis, it became as shown in FIG. 10 .

In Fig. 10, "x" is an example in which the maximum load per mass is smaller than that of the comparative example at the same aspect ratio (x), and examples 10, 15, and 20 correspond to them. However, even in Examples 10, 15, and 20, the absolute value of the maximum load is larger than that of the comparative example with the same aspect ratio (x).

As described above, by forming the tension member 12, the absolute value of the maximum load of the structural member increased compared to the case where the tension member 12 was not provided.

In addition, it was found that when the height of the tension member 12 is determined so as to satisfy the above expression (1), the maximum load per mass also increases compared to the case where the tension member 12 is not provided.

In addition, the relationship between the bending radius (bending R) of the bending portion of the flange portion 12a of the tension member 12, the plate thickness, and the tensile strength with respect to the load in the bending crushing direction was evaluated. Specifically, the tensile strength of the tension member 12, the plate thickness, and the maximum load per mass when the radius of curvature (bending R) of the bending portion between the tension member 12 and the flange portion 12a formed at the end thereof were changed.

The evaluation result is shown in Table 4.

The tension member 12 is for obtaining a larger tensile force with respect to the opening of the pair of side wall portions 10B at the time of collision.

As can be seen from Table 4, as shown in Example 2 and Example B, when the tensile strength and plate thickness of the tension member 12 are the same, it was found that the smaller the radius of curvature of the bent portion is preferable.

In addition, when the plate thickness of the tension member 12 and the radius of curvature of the bent portion are equal, as shown in Example 2 and Example A of Table 4, the higher the tensile strength of the tension member 12, the higher the anti-collision performance. It was found that. However, as described above, the radius of curvature is preferably smaller, and as shown in Example A and Example B, by setting the tensile strength of the tension member 12 low, for example, 590 MPa or less, even if the strength is lowered from the 1470 MPa grade to the 590 MPa grade, it was found that it is preferable to reduce the radius of curvature to 0.3 mm.

In addition, when the tensile strength of the tension member 12 and the radius of curvature of the bent portion are equal, as shown in Example B and Example C, the thicker the plate thickness of the tension member 12, the higher the crash resistance performance. It was found to be obtained. However, as described above, the radius of curvature is preferably smaller. When the radius of curvature is set as small as, for example, 0.3 mm or less, in order to realize molding at the bent portion, the thickness of the tension member 12 is preferably thinner, and as shown in Examples 2 and 3, the thickness of the tension member 12 is preferably, for example, about 0.8 mm. Therefore, the plate thickness of the general tension member 12 is preferably 50% or more and 60% or less of the plate thickness of the hat end face member 10, for example.

Here, the entire contents of Japanese Patent Application No. 2019-033075 (filed on February 26, 2019) and Japanese Patent Application No. 2020-005697 (filed on January 17, 2020) to which this application claims priority are made a part of this disclosure by reference. Here, although the description was made with reference to a limited number of embodiments, the scope of rights is not limited thereto, and modifications of each embodiment based on the above disclosure are obvious to those skilled in the art.

1: hollow member
10: hat section member
10A: top plate
10Ab: concave part
10B: side wall
10C: Flange
11: bottom plate
12: absence of tension
p: reinforcement position
w : width
x: member aspect ratio
y: reinforcement height ratio

Claims (3)

A hollow member constituting a closed cross-sectional shape with a top plate portion, a pair of side wall portions each successive on both sides in the width direction of the top plate portion, and a bottom plate portion disposed opposite to the top plate portion;
The top plate portion has one or two or more concave portions recessed toward the bottom plate portion along the width direction of the top plate portion, and each concave portion is composed of a pair of upright portions facing each other in the width direction and a bottom portion connecting between the pair of upright portions,
The tension member connects an inner surface of the side wall portion and an upright portion of a concave portion of the top plate portion facing the inner surface of the side wall portion, with a space between the inner surface of the top plate portion and the tension member. According to claim 1,
The structural member for a vehicle according to claim 1 , wherein the tension member extends to the bottom portion along an inner surface of the concave portion at a junction to the upright portion. delete