JP7192837B2 - Vehicle structural member - Google Patents

Description

TECHNICAL FIELD The present invention relates to a vehicle structural member (framework member) having a closed cross-sectional structure composed of two hat members. In particular, the present invention relates to a technique for providing a structural member having collision resistance against bending deformation due to a collision load input from a direction along the direction in which two top plate portions face each other.

In recent years, in the automobile field, collision safety standards have been tightened from the viewpoint of passenger protection, and there is a strong demand for the expansion of the application of high-strength steel and the development of vehicles with excellent collision safety performance.
Here, as the form of collision, there are a collision form of axial crush (axial crush mode) and a collision form of bending deformation (bending crush mode). In a collision mode that causes axial crushing, axial crushing occurs when the longitudinal direction of a member coincides with the direction of collision, such as a crash box or a front side member that receives a collision load input from the front of an automobile. In a collision mode in which bending deformation occurs, a collision load is applied to the side surface of a structural member such as a B-pillar or a side sill in a side collision, and the member bends and deforms. Both forms exhibit collision resistance performance by absorbing collision energy through buckling deformation of the member.

A structural member having a closed cross-sectional structure using a hat member is often adopted as a structural member for a vehicle that requires the above collision resistance performance.
As one of the techniques for improving the collision resistance performance of a structural member having a closed cross-section structure using such a hat member, there is a technique for improving the strength of the surface rigidity of the structural member by attaching a reinforcing member to the surface of the member. Proposed. For example, Patent Literature 1 describes that a reinforcing member is arranged in close contact with the inner surfaces of the bottom plate portion and the top plate portion that constitute the hollow member. Further, in Japanese Unexamined Patent Application Publication No. 2002-100001, a reinforcing member is provided that is joined to a ridge connecting a top plate portion and a side wall portion, and a welded portion to the reinforcing member is provided at the ridge. Further, in Patent Document 3, a steel plate member combination structure includes a first steel plate member having a main wall portion, a rising wall portion, and a flange portion, and a second steel plate member joined to the inner or outer surface of the ridge portion. describes improving the collision energy absorption efficiency.

JP 2017-159896 A JP 2014-87848 A WO2017/030191 JP 2012-66795 A

The methods described in Patent Documents 1 to 3 are known to be excellent reinforcement methods for the crash characteristics of the axial crush mode. However, the methods described in Patent Documents 1 to 3 are optimal reinforcement methods for crash characteristics in the case of a bending crush mode and also in the case of a part such as a rocker in which a hat member is also used for the bottom plate. It is hard to say that it is. That is, in the method of Patent Document 1, it is necessary to use a filling member formed of foamed resin or the like as a sub-reinforcing member separately from the main reinforcing member made of a plate material or the like. There is a problem. In addition, in the method disclosed in Patent Document 2, the main reinforcing member is joined to the side wall portion and the ridge line portion, but since no consideration has been given to the reinforcing position, it is difficult to say that it is an effective reinforcing position for each part shape. Hard to say. In addition, in the method disclosed in Patent Document 3, the length of the vertical wall defines the range in which the reinforcing member is joined. , it is difficult to say that it is an effective reinforcement.

Further, in Patent Document 4, a connecting wall (reinforcing member) is provided for each hat member in a structural member having a closed cross section formed by combining two hat members, thereby improving the resistance against collision in bending crush mode. Although the structure has been examined, it is difficult to say that the reinforcement is effective for the optimum reinforcement position that differs for each member, as in Patent Document 3.

Furthermore, simply attaching a reinforcing member to the surface of a structural member improves crash resistance, but increases the number of parts, resulting in an unnecessary increase in the mass of the structural member and an increase in the number of dies. Therefore, conventionally, there is a problem in terms of cost. In particular, in the conventional art, the larger a region is to be reinforced with a reinforcing member, the greater the increase in mass.

The present invention focuses on the above points, and aims to effectively improve the collision resistance performance of structural members, especially the collision resistance performance against bending crush mode, while suppressing an unnecessary increase in the mass of structural members. purpose.

The present inventor studied the effective reinforcement position in a hollow member that constitutes a closed cross-sectional shape, and in particular, with respect to a closed cross-sectional structural member that is formed by combining two hat members, studied the deformation mode against a collision load. The reinforcement method and the effective reinforcement position were studied earnestly. As a result of the earnest investigation, the present invention was made.

In order to solve the problem, one aspect of the present invention provides two hat members each having a hat-shaped cross section in which a side wall portion and a flange portion are continuous on both sides of a top plate portion. It is composed of a hollow member forming a shape and a metal plate extending along the width direction of the top plate portion, and the inner surfaces of two opposing side wall portions are connected to each other to widen the distance between the two side wall portions. and a tension member for restraining the

Further, according to one aspect of the present invention, for example, in the two hat members, the height of the other hat member is lower than the height of the other hat member and is 0.5 times the height of the one hat member. and the thickness of the tension member is thinner than the thickness of the hollow member.

In another aspect of the present invention, two hat members each having a hat-shaped cross section in which a side wall portion and a flange portion are continuous on both sides of a top plate portion are joined to each other to form a hollow cross-sectional shape with a closed cross-sectional shape. and a tension member comprising a metal plate extending along the width direction of the top plate portion and connecting the inner surfaces of two opposing side wall portions to restrain the distance between the two side wall portions from increasing. and wherein the thickness of the tension member is thinner than the thickness of the hollow member, and the top plate portions of the two hat members are arranged to face each other vertically. Among the members, the height of the upper hat member is h1, the height of the lower hat member is h2, and the vertical distance from the top plate of the upper hat member to the tension member is the reinforcement position p. , the gist is that the reinforcement height ratio r defined by the following formula (1) satisfies the following formula (2).
r = (h1-p)/h1 : when h1 > p r = (h1-p)/h2 : when h1 < p
... (1)
−0.5≦r≦0.375 (2)

According to the aspect of the present invention, since the reinforcing member is joined to the effective reinforcing position in the hollow member that forms the closed cross-sectional shape with the two hat members, the reinforcement can be performed at the more effective reinforcing position. . That is, according to the aspect of the present invention, it is possible to effectively improve the collision resistance performance of the structural member, particularly the collision resistance performance per member mass against the bending crush mode, while suppressing an unnecessary increase in the mass of the structural member. It becomes possible.

1 is a perspective view of a structural member according to an embodiment of the invention; FIG. 1 is a cross-sectional view of a structural member according to an embodiment of the invention; FIG. It is a conceptual diagram explaining a three-point bending crush test. It is a figure which shows an example of the relationship between a load and a deformation|transformation stroke. It is a figure explaining the behavior of member deformation|transformation by a three-point bending crush test, (a) shows the state with deformation stroke amount: 20 mm, (b) shows the state with deformation stroke amount: 60 mm. In FIG. 5, the upper drawing is a cross-sectional view, and the lower drawing is a side view. It is a figure which shows the relationship between reinforcement height ratio r and the maximum load per mass. FIG. 3 is a diagram showing the result of summarizing the horizontal axis as the plate thickness t of the tension member and the vertical axis as the maximum load per mass of the structural member. It is a figure which shows the relationship between a reinforcement height ratio r and a performance improvement ratio.

Next, embodiments of the present invention will be described with reference to the drawings.
(composition)
The vehicle structural member of the present embodiment has a hollow member 1 and a tension member 5 that reinforces the hollow member 1, as shown in FIGS.

<Hollow member 1>
The hollow member 1 forms a closed cross-sectional shape by joining two hat members 1A and 1B with flange portions 4A and 4B.
Each of the hat members 1A and 1B is a hat-shaped cross-sectional member having top plate portions 2A and 2B, and side wall portions 3A and 3B and flange portions 4A and 4B that are continuous on both sides of the top plate portions 2A and 2B, respectively. Each hat member 1A, 1B has two side wall portions 3A, 3B facing each other in the width direction of the top plate portions 2A, 2B. The opposing flange portions 4A and 4B of the hat members 1A and 1B are welded to each other, so that the structural member has a closed cross section.

Here, in this specification, as shown in FIGS. 1 and 2, the top plate portions 2A and 2B of the two hat members 1A and 1B are arranged to face each other vertically. When distinguishing between the two hat members 1A and 1B, the upper hat member 1A is referred to as the first hat member 1A, and the lower hat member 1B is referred to as the second hat member 1B. In this embodiment, it is assumed that an impact from the side of the structural member is likely to be input to the first hat member 1A side.

The two hat members 1A, 1B need not have the same dimensions. For example, the height h2 of the second hat member 1B may be lower than the height h1 of the first hat member 1A. As for the height ratio of the two hat members 1A and 1B, for example, the ratio of the larger hat member to the smaller hat member is 1:1 to 1:0.5. That is, when the two hat members have different heights, the height of the hat member with the lower height is lower than the height of the hat member with the higher height, and the height of the hat member with the higher height is lower than that of the hat member with the higher height. The height should be 0.5 times or more the height.

The height of the hat members 1A, 1B refers to the height from the flange portions 4A, 4B to the top plate portions 2A, 2B. Further, in this embodiment, in each of the hat members 1A and 1B, the heights of the left and right side wall portions 3A and 3A and 3B and 3B are substantially equal. The right and left side walls having the same height means that the height difference between the left and right side walls is within 2 mm.

One or more beads extending in the longitudinal direction may be formed on the top plate portions 2A and 2B. By providing the beads extending in the longitudinal direction, the strength of the vehicle structural member against load input in the direction along the longitudinal direction of the hollow member 1 is improved.
1 and 2 also show the dimensions of the members in the embodiment, but these dimensions do not limit the present invention.

<Tension member 5>
The tension member 5 is made of a metal plate extending in the width direction of the top plate portions 2A and 2B. The tension member 5 is a member that connects the inner surfaces of the two side wall portions 3A or 3B facing each other on the left and right sides and restricts the opening between the two side wall portions 3A and 3B.
The plate thickness of the tension member 5 is set according to the specifications required for the portion where it is used.

In this embodiment, the thickness of the tension member 5 is, for example, less than the thickness of the hollow member 1, 0.6 mm or more, preferably 0.8 mm or less and 0.6 mm or more. Moreover, it is preferable to set the plate thickness of the tension member 5 to, for example, 50% or more and 80% or less of the plate thickness of the hat members 1A and 1B. Here, when setting the plate thickness of the tension member 5 to be less than the plate thickness of the hollow member 1, if the hat members 1A and 1B constituting the hollow member 1 have different plate thicknesses, the hat members 1A and 1B The value of the plate thickness of the hat member on the thinner side is used.

The tension member 5 made of a metal plate is preferably parallel or substantially parallel to the surfaces of the top plate portions 2A and 2B. The tension member 5 may be provided in a state inclined in the width direction or the longitudinal direction of the top plate portions 2A and 2B with respect to a virtual plane parallel to the surfaces of the top plate portions 2A and 2B.
The tension member 5 forms a space between the tension member 5 and the inner surface of each of the top plate portions 2A and 2B, and is arranged so as to vertically partition the space between the opposing top plate portions 2A and 2B.

The two side wall portions 3A or 3B connected by the tension member 5 are the two laterally opposed side wall portions 3A of the first hat member 1A or the two laterally opposed side wall portions of the second hat member 1B. 3B. That is, one tension member 5 is interposed between the two top plate portions 2A and 2B. Although two or more tension members 5 may be interposed between the two top plate portions 2A and 2B, one tension member 5 is preferable because it leads to an increase in the mass of the structural member.

Both sides in the width direction of the tension member 5 are joined (connected) to the inner surfaces of the two opposing side wall portions 3A or 3B by welding. In FIG. 2, for example, flange portions are formed at both ends in the width direction of the tension member 5, and the tension member 5 is attached by abutting and welding the surfaces of the flange portions against the inner surfaces of the side wall portions 3B. However, the method of joining the tension member 5 and the inner surface of the side wall portion 3A or 3B is not particularly limited. The joining is performed, for example, by laser welding, spot welding, or an adhesive.

The tension member 5 has a curvature of the bending portion between the tension member 5 and the flange formed at its end so that a larger tensile force can be obtained for the opening of the two side wall portions 3A and 3B at the time of collision. A smaller radius is preferred. It is preferable that the thickness of the tension member 5 is thin in consideration of the moldability of the flange portion and in order to make the radius of curvature of the bent portion smaller. Moreover, the higher the tensile strength of the tension member 5, the better. However, if the curvature radius of the bent portion is set as small as 0.3 mm or less, for example, the tensile strength of the tension member 5 is set as low as 590 MPa or less in order to realize molding at the bent portion. Here, the tension member 5 is mainly for bearing the tensile force. That is, since the plate thickness of the tension member 5 does not contribute much to the tensile force, it is preferable that the plate thickness of the tension member 5 is thin from the viewpoint of weight reduction. Therefore, it is preferable to reduce the radius of curvature of the bent portion even if the strength of the tension member 5 is lowered.

Here, the tension member 5 does not have to be provided continuously over the entire longitudinal direction of the hollow member 1 . The tension member 5 may be partially provided along the longitudinal direction of the hollow member 1 . In this case, in plan view, the tension member 5 is preferably provided at a location including at least a position where the collision load is likely to be applied.

The surface position of the top plate portion 2A where the collision load is likely to be applied is determined based on the vehicle position where the structural member is arranged, based on past accident information, etc. It is estimated based on which part of the structural member to which the collision load is likely to be input.

Further, the deformation area is determined by analyzing the deformation position of the member by, for example, FEM simulation analysis. As the preset collision load, the permissible collision load required as collision resistance performance at the position where the structural member is used is adopted.
Also, when the two hat members 1A and 1B have different heights, the tension member 5 may be provided on either hat member, but is provided on the lower hat member side, for example.

Further, for example, the tension member 5 is arranged at a position where it is estimated that a collision load along the opposing direction of the top plate portions of the two hat members 1A and 1B is likely to be applied. If known, the tension member 5 is preferably provided on the hat member located on the side opposite to the hat member located at the position where the collision load is likely to be applied.

<Height Position of Tension Member 5>
Next, a suitable arrangement position (position in the height direction) of the tension member 5 made of a metal plate will be described.
Here, as shown in FIG. 2, of the two hat members 1A and 1B, the height of the first hat member 1A (upper hat member 1A) is set to h1, and the height of the second hat member 1B (lower hat member 1A) is set to h1. Let h2 be the height of the member 1B). Further, the vertical distance from the top plate portion 2A of the first hat member 1A to the tension member 5 is defined as a reinforcing position p. Let H be the height of the structural member, and w be the width of each hat member.

When the heights of the two hat members 1A and 1B are different, for example, the hat member having the higher height among the two hat members 1A and 1B is defined as the first hat member 1A. The lower hat member may be used as the first hat member 1A.

Further, for example, when provided in a vehicle, the hat on the side that is arranged at a position where it is estimated that there is a high possibility that a collision load is applied along the opposing direction of the top plate portions of the two hat members 1A and 1B. Let the member be the 1st hat member 1A.

The tension member 5 is provided to bear the tensile force when the two left and right side wall portions 3A and 3B are about to widen. Therefore, the reinforcing position p is a position where the tension member 5 applies tensile force when the space between the left and right side wall portions 3A and 3B is about to widen. That is, when the tension member 5 is a flat plate, the reinforcement position p is, for example, the value at the central position in the thickness direction of the tension member 5 . When the surface of the tension member 5 is arranged in a tilted state, the reinforcement position p is, for example, a value at the central position of the tension member 5 or the center of gravity of the tension member 5 in plan view.

At this time, it is preferable to set the height position of the tension member 5 so as to satisfy the following formulas (1) and (2) (see Examples).
By satisfying the formulas (1) and (2), it is possible to improve the collision resistance performance more efficiently with respect to collisions in the bending crush mode.
r = (h1-p)/h1 : when h1 > p r = (h1-p)/h2 : when h1 < p
... (1)
−0.5≦r≦0.375 (2)
More preferably, it satisfies the following formula (3).
−0.25≦r≦0.125 (3)
Note that if h1>p, r is greater than zero, and if h1<p, r is less than zero.

<Operation and others>
By FEM analysis, the inventors found that a structural member (a hollow member 1 without a tension member 5) having a closed cross section composed of hat members 1A and 1B having dimensions as shown in FIGS. The member deformation behavior in the crush test was analyzed in detail. As shown in FIG. 3, the three-point bending analysis conditions are such that two points on the lower surface of the structural member separated in the longitudinal direction are supported by a support member 10, and a punch is applied to the central portion in the longitudinal direction of the top plate portions 2A and 2B. 11 is a condition that the load is applied from the upper side toward the lower side. Specifically, the punch 11 was moved at a speed of 1 m/s in the direction indicated by the arrow F in FIG. Moreover, the deformation stroke of the structural member, which is the test piece, was set to 80 mm. FIG. 4 shows the relationship between the load and the deformation stroke at that time.

As shown in FIG. 5, which is a cross section at the center of the member, the member deformation behavior based on the above analysis is such that the first hat member 1A is deformed and the second hat member 1B is deformed in accordance with the deformation of the member. The left and right side wall portions 3B are deformed so as to open outward. It was found that this deformation caused the member to bend in a V shape, and the load applied to the member was reduced as shown in FIG. Here, in FIG. 5, (a) shows the state when the deformation stroke is 20 mm, and (b) shows the state when the deformation stroke is 60 mm.

Therefore, if the maximum load at this time is regarded as the collision resistance performance, in order to increase the maximum load, it is necessary to suppress the opening of the two side wall portions 3A and 3B facing each other on the left and right sides as described above to improve the collision resistance performance. I thought it would be effective for

Therefore, in this embodiment, as shown in FIGS. 1 and 2, by providing a tension member 5 as a reinforcing member so as to connect the left and right side wall portions 3A or 3B, when the member is deformed due to a collision from the side, On the other hand, there is an effect that the opening of the opposing side wall portions 3A and 3B is suppressed.

In particular, as will be shown in the examples below, by providing the tension member 5 so that the reinforcement height ratio r satisfies the formulas (1) and (2), the mass of the structural member is increased more than necessary. is suppressed, it is possible to effectively improve the collision resistance performance of the structural member, particularly the collision resistance performance per member mass against the bending crush mode.

As shown in FIG. 5, the deformation due to the collision spreads the left and right side wall portions 3B of the second hat member 1B, which is the side opposite to the side to which the collision load is input. For this reason, the tension member 5 may simply be provided for the second hat member 1B, not the first hat member 1A, to which the collision is presumed to be input. By connecting the opposing side wall portions 3B of the second hat member 1B with the tension member 5, the opposing side wall portions 3A and 3B are not deformed due to a collision such as a load input to the top plate portion 2A, for example. It is possible to efficiently suppress an increase in the distance between the two and improve the anti-collision performance. At this time, the left and right side walls tend to widen relatively on the flange portion 4B side of the second hat member 1B, so for example, the reinforcement position p represented by the distance from the upper top plate portion 2A is ( 4) within the range of the formula.
h1<p<h1+(h2/2) (4)
Further, when the tension member 5 is provided on the first hat member 1A side, for example, the reinforcing position p is set within the range of the formula (5).
0.625·h1≦p<h1 (5)

As described above, in this embodiment, by providing the tension member 5 as described above, it is possible to improve the collision resistance performance of the structural member, particularly in the collision mode in which bending deformation occurs. The tension member 5 of the present embodiment restrains, by tension (pulling force), the two side wall portions 3A and 3B facing each other in the width direction from being displaced in the separating direction. As a result, the bulging (buckling) of the two opposing side wall portions 3A and 3B in the out-of-plane direction is suppressed with respect to the input of the collision load to the top plate portions 2A and 2B. That is, by providing the tension member 5 based on this embodiment, it is possible to effectively suppress member cross-sectional deformation at the time of collision, and particularly to increase the maximum load in bending deformation.

Moreover, since the tension member 5 made of a metal plate bears the tensile force against the collision load and does not necessarily bear the compressive force, even a thin metal plate is effective. That is, even if the tension member 5 is provided in order to improve the anti-collision performance, it is possible to suppress an increase in load compared to the conventional art. That is, even if the tension member 5 made of a metal plate is provided as a reinforcing member, it is possible to suppress the increase in the mass caused by the tension member 5 .

Next, examples based on the present invention will be described.
Considering the construction as shown in FIGS. 1 and 2, the joining of the tension member 5 in the embodiment is a case where continuous joining is performed.
The hat members 1A and 1B and the tension member 5 were set as shown in Table 1. Also, the hat cross-sectional shape was analyzed by setting the cross-sectional shape to the specifications of "1" to "6" as shown in Table 2.

Then, the three-point bending crush test by the FEM analysis described above was performed by setting the cross-sectional shape to "1" and changing the reinforcement height ratio r. Table 3 shows the results.

Table 3 shows the maximum load per mass of the structural member when the cross-sectional shape is "1".
Here, Examples 1 to 11 are the results when reinforcement is performed by arranging the tension member 5 at the reinforcement position p corresponding to each reinforcement height ratio r, and Comparative Example 1 does not provide the tension member 5. This is the result when

FIG. 6 shows the result of summarizing the reinforcement height ratio r on the horizontal axis and the maximum load per mass of the structural member on the vertical axis. In FIG. 6, the values for Comparative Example 1 are indicated by horizontal lines.
As can be seen from FIG. 6, the maximum load per mass is maximized when the reinforcement height ratio r is -0.1 or around it.

Next, the three-point bending crush test by the FEM analysis described above was performed by changing the plate thickness t of the tension member 5 in Example 5, in which the performance improvement ratio was maximized among the results shown in Table 3. . Table 4 shows the results.

Table 4 shows the maximum load per mass of the structural member when the plate thickness t of the tension member 5 is changed when the cross-sectional shape is "1" and the reinforcement height ratio r is -0.171. Here, Comparative Example 1 is the result when the tension member 5 is not provided.

FIG. 7 shows the result of summarizing the thickness t of the tension member on the horizontal axis and the maximum load per mass of the structural member on the vertical axis.
As can be seen from FIG. 7, the maximum load per mass is maximized when the plate thickness t of the tension member 5 is 0.8.

Next, the three-point bending crushing test by the FEM analysis described above was performed by setting the cross-sectional shape to any one of "2" to "6" and changing the reinforcement height ratio r. Table 5 shows the results.

Table 5 shows the maximum load per mass when the cross-sectional shape is "2" to "6". Tables 3 and 5 also show the performance improvement ratio values of the tension member 5 for each cross-sectional shape. This value is obtained by dividing the maximum load per mass at each reinforcement height ratio r by the maximum load per mass without the tension member 5 .

FIG. 8 shows results obtained by plotting the reinforcement height ratio r on the horizontal axis and the performance improvement ratio on the vertical axis for each cross-sectional shape.
As shown in FIG. 8, it can be seen that the performance improvement ratio by the tension member 5 is maximized when the reinforcement height ratio r is -0.1 or around it, regardless of the cross-sectional shape of the structural member. . Moreover, it was found that the performance was significantly improved when the reinforcement height ratio r was -0.5 or more and 0.375 or less. It was found that it is more preferably -0.25 or more and 0.125 or less, and further -0.25 or more and 0.00 or less.

1 Hollow member 1A First hat member 1B Second hat members 2A, 2B Top plate portions 3A, 3B Side wall portions 4A, 4B Flange portion 5 Tension member p Reinforcement position r Reinforcement height ratio

Claims (3)

a hollow member that forms a closed cross-sectional shape by joining two hat members each having a hat-shaped cross section in which a side wall portion and a flange portion are continuous on both sides of a top plate portion;
a tension member made of a metal plate extending along the width direction of the top plate portion and connecting inner surfaces of two opposing side wall portions to restrain the distance between the two side wall portions from increasing;
with
In the two hat members, the height of the other hat member is lower than the height of the other hat member and is 0.5 times or more the height of the one hat member,
The thickness of the tension member is thinner than the thickness of the hollow member,
The tension member connects inner surfaces of two opposing side walls of the other hat member.
A structural member for a vehicle characterized by: a hollow member that forms a closed cross-sectional shape by joining two hat members each having a hat-shaped cross section in which a side wall portion and a flange portion are continuous on both sides of a top plate portion;
a tension member made of a metal plate extending along the width direction of the top plate portion, and connecting inner surfaces of two opposing side wall portions to restrain an increase in the distance between the two side wall portions;
with
The thickness of the tension member is thinner than the thickness of the hollow member,
The two hat members are such that the height of the other hat member is lower than the height of the one hat member, and the tension member connects inner surfaces of two opposing side walls of the other hat member,
In a state in which the top plate portions of the two hat members are vertically opposed to each other,
Of the two hat members, the height of the upper hat member is h1, the height of the lower hat member is h2, and the vertical distance from the top plate of the upper hat member to the tension member is the reinforcement position p,
A structural member for a vehicle, wherein a reinforcement height ratio r defined by the following formula (1) satisfies the following formula (2).
r = (h1-p)/h1 : when h1 > p r = (h1-p)/h2 : when h1 < p
... (1)
−0.5≦r≦0.375 (2) In the two hat members, the height of the other hat member is lower than the height of the other hat member and is 0.5 times or more the height of the one hat member.
The vehicle structural member according to claim 2, characterized in that:

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