WO2010013713A1 - Bending strength member and bumper reinforcement having same - Google Patents

Abstract

Disclosed is a bending strength member which can be improved in the bending strength while an increase in the weight being minimized.  The bending strength member comprises a pair of flanges (2, 3) so disposed as to face each other in the colliding direction and a web (5) having a variable cross-section disposed between the flanges parallel to each other in the colliding direction.  The web (5) is so shaped that the wall thicknesses at both ends are larger than the wall thickness on the inner side, whereby the buckling strength of the web (5) is increased, and the bending strength of the member can be improved.

Description

Bending strength member and bumper reinforcement including the same

The present invention relates to a bending strength member to which a bending load due to an external force acts, and a bumper reinforcement including the bending strength member.

Conventionally, a bumper reinforcement attached to a car body of an automobile is an example of a bending strength member made of a thin material and subjected to a bending load due to an external force. Many of such bumper reinforcements are molded using a 980 MPa grade steel plate into a B-shaped cross section or a cross section in which a plate material for vertically partitioning it is arranged in a hollow rectangular cross section.

The main role of the bumper reinforcement is to absorb the energy at the time of collision by deforming and absorbing energy at the time of collision, and transmitting the impact load to the left and right side members to deform the side members. That is, by deforming the side member and absorbing energy, the deformation of the cabin of the automobile is suppressed as designed to protect the passenger from impact.

Patent Document 1 discloses an automotive bumper reinforcement in which bending strength is increased by making a portion on the compression flange side thicker than a portion on the tension flange side with respect to the bending neutral axis of the web constituting the hollow rectangular cross section. Has been. Further, Patent Document 2 discloses a vehicular bumper device having a bumper force having three ribs arranged in a specific direction. In this device, the thickness of ribs at intermediate positions among these ribs is changed. By making it larger than this rib, the energy absorbing ability is prevented from being lowered when the three ribs are buckled.

Patent Document 3 discloses a bending strength member having a flange to which a bending load acts and a flange on the opposite side thereof. In this bending strength member, an FRP material is provided on the flange surface of the latter flange. The amount of energy absorption is increased by setting the ratio of the width and thickness of the flange on the compression side to 12 or less. Patent document 4 includes a steel pipe and a composite of a vehicle including a steel pipe and a reinforcing rod having an outer shape along the inner wall thereof and having a rib formed therein, and the strength is ensured by inserting the reinforcing pipe into the steel pipe. A structural member is disclosed.

Patent Document 5 discloses a filling structure having a hollow member and a filler rich in energy absorption performance, and the corrosion resistance is ensured by inserting and fixing the filler into the hollow member. Is disclosed. Further, Patent Document 6 discloses a vehicle body structural member that is composed of a plurality of members having different strengths so that a torsional moment is generated, and has improved energy absorption efficiency by dispersing a bending load to other members. ing.

Further, Patent Document 7 discloses a bumper structure having a bumper reinforcing material having a hollow portion and a crush preventing body that is disposed in the hollow portion and improves impact energy absorption capability due to buckling deformation. Yes. Further, Patent Document 8 discloses an automobile bumper in which a limit load of buckling is improved by providing an R provided in a concave shape toward the center direction of the reinforcing material on a surface that is not perpendicular to the load direction of the load. A reinforcement is disclosed.

By the way, in a bending strength member with a hollow cross section such as a bumper reinforcement, in order to demonstrate the theoretical cross section performance, when subjected to a collision load, the flange is buckled before the entire section is plasticized. It is indispensable condition not to generate.

In order to prevent the web from buckling, it is effective to increase the thickness of the web. However, since the increase in web thickness causes an increase in weight, the performance per weight is not improved so much. In addition, an increase in web wall thickness leads to an increase in weight as it is, but today there is a background that a reduction in vehicle weight is required to reduce CO ₂ .

In addition, it is difficult to manufacture an attachment in the cross section of the bumper reinforcement, and it is difficult to manufacture. Further, it is hardly possible to prevent compression buckling with FRP. In addition, when these adducts are used, there is a problem that the cost is significantly increased.

JP 11-059296 A JP 2004-148915 A JP 2003-129611 A JP 2003-312404 A Japanese Patent Laid-Open No. 2005-088651 JP 2006-248336 A JP 2000-052897 A JP-A-6-199193

An object of the present invention is to provide a bending strength member capable of improving the bending strength while minimizing an increase in weight, and a bumper reinforcement including the bending strength member.

The bending strength member according to the present invention is disposed so as to oppose each other in a load application direction to which a load is applied, each of which is perpendicular to the load application direction, and the load application direction between the pair of flanges And a web having a shape in which the thickness of the inner portion is larger than the thickness of both ends. This web has a higher buckling strength in the load application direction than a web having the same cross-sectional area as that of the web and having a constant wall thickness from one end to the other end. In this way, the web buckling strength can be improved by increasing the thickness on the inner side than the thickness at both ends, without increasing the thickness of the web uniformly from one end to the other. The bending strength can be improved while minimizing the increase in weight due to the thickening of the web.

It is a schematic diagram of the bumper reinforcement according to the first embodiment of the present invention. (A)-(c) is sectional drawing of the said bumper reinforcement. (A)-(c) is sectional drawing of the conventional bumper reinforcement. It is a graph showing the simulation result about the buckling strength of the web in the said bumper reinforcement. (A)-(c) is sectional drawing of the bumper reinforcement which concerns on the 2nd Embodiment of this invention. It is a graph showing the simulation result about the buckling strength of the web in the bumper reinforcement which concerns on the 2nd Embodiment of this invention. It is sectional drawing of the bumper reinforcement which concerns on the 3rd Embodiment of this invention. It is sectional drawing of the bumper reinforcement which concerns on the 4th Embodiment of this invention. (A) And (b) is sectional drawing of the variable cross-section web of the bumper reinforcement which concerns on the 4th Embodiment of this invention. It is a graph showing the simulation result about the buckling strength of the web in the bumper reinforcement which concerns on the 2nd Embodiment of this invention. (A) And (b) is sectional drawing which shows the modification of the bumper reinforcement which concerns on this invention. (A)-(c) is sectional drawing which shows the modification of the bumper reinforcement which concerns on this invention. (A) And (b) is sectional drawing which shows the modification of the bumper reinforcement which concerns on this invention. It is sectional drawing which shows the modification of the bumper reinforcement which concerns on this invention.

Hereinafter, an embodiment of a bending strength member according to the present invention will be described based on the drawings. In these embodiments, a bumper reinforcement attached to a vehicle body is described as a bending strength member, but the bending strength member according to the present invention is not limited to a bumper reinforcement. Moreover, the bumper reinforcement according to each embodiment may include other components in addition to the bending strength member according to the present invention.

[First Embodiment]
A bumper reinforcement (bending strength member) 1 according to a first embodiment of the present invention will be described with reference to FIGS.

(Configuration of Bumper Reinforcement 1)
The bumper reinforcement 1 in the present embodiment is made of a metal material such as aluminum or steel, and is entirely molded integrally. As shown in FIG. 1, the bumper reinforcement 1 has a shape extending in a specific direction, and the longitudinal direction of the bumper reinforcement 1 is orthogonal to the collision direction indicated by an arrow (load addition direction to which a load is applied). It is attached to the front of the vehicle body 100. Specifically, the bumper reinforcement 1 is supported by a pair of stays 8 and 8 provided at a predetermined interval in a direction orthogonal to the collision direction.

FIG. 2 shows a cross section corresponding to the cross section taken along line AA shown in FIG. As shown in FIG. 2, the bumper reinforcement 1 has a hollow rectangular cross section, and the hollow portion is partitioned vertically by a horizontal web. Specifically, the bumper reinforcement 1 is disposed so as to face each other in the collision direction, and a pair of the front flange 2 and the rear flange 3 that are orthogonal to the collision direction, and between the flanges 2 and 3. 3, three webs 4, 4, 5 are arranged so as to be lined up and down in a posture parallel to the collision direction. The number of webs is not limited to three.

The front flange 2 is located on the upstream side in the collision direction indicated by the arrow, and the rear flange 3 is located on the downstream side in the collision direction with respect to the front flange 2. The front flange 2 and the rear flange 3 are connected to each other by the three webs 4, 4, and 5.

Two of the three webs 4, 4, 5 are respectively disposed between both ends of the front flange 2 and both ends of the rear flange 3 facing the both ends. . Further, the web 5 is disposed between a longitudinal center portion which is a portion inside the both end portions of the front flange 2 and a longitudinal center portion which is a portion inside the both end portions of the rear flange 3. Is done. Each of the end side webs 4, 4 has a constant thickness from one end to the other end. Such a web is called a constant section web. On the other hand, the inner web 5 has such a thickness that the inner portion is thicker than the both end portions. Such a web is called a variable cross section web. The thicknesses of the constant cross-section web 4 and the variable cross-section web 5 are set so that the cross-sectional areas of the constant cross-section web 4 and the variable cross-section web 5 viewed from the direction orthogonal to the collision direction are the same.

As shown in FIG. 2A, the constant cross-section web 4 has a length L in a direction parallel to the collision direction, and a wall thickness t3 that is constant from one end to the other end. The cross-sectional shape of the constant cross-section web 4 is a rectangle. On the other hand, the variable cross-section web 5 has a length L in a direction parallel to the collision direction and a thickness that varies from one end to the other end. Specifically, both end portions of the cross-section web 5 have a thickness t1, and the central portion, which is a distance of L / 2 from each end portion, has the maximum thickness t2. The cross-sectional shape of the variable cross-section web 5 is bilaterally symmetric when the direction orthogonal to the collision direction is left and right, so that the central portion is the thickest thickest portion from both ends to the central portion. The shape is such that the wall thickness continuously increases toward.

On the other hand, as shown in FIG. 3 (a), in the conventional bumper reinforcement 31, all of the three webs have constant cross-sectional webs 14, 14 whose both end portions and central portion have a constant thickness t3. , 15. Each of these constant cross-section webs 14, 14 and 15 is the same as the constant cross-section web 4 shown in FIG.

That is, the conventional bumper reinforcement 31 has the constant cross-section web 15 having a constant thickness between the longitudinal center portions of the pair of flanges 2 and 3, whereas the bumper according to the present embodiment. The lean reinforcement 1 has a variable cross-section web 5 between the longitudinal center portions of the pair of flanges 2 and 3, the inner thickness being larger than the thickness at both ends. The variable cross-section web 5 has a buckling strength higher than that of the constant cross-section web 15 having the same cross-sectional area as the variable cross-section web 5 because the inner thickness is larger than the thickness of both ends thereof.

Here, in the variable cross-section web 5, the thickness t1 at both ends and the thickness t2 at the thickest portion satisfy the following formula 1. In other words, the wall thickness t1 at both ends of the variable cross section web 5 and the wall thickness t2 at the thickest part are set so as to satisfy Expression 1. As a result, it is possible to suitably improve the bending strength of the bumper reinforcement 1 while minimizing an increase in weight.

1.1 ≦ t2 / t1 ≦ 1.4 (Formula 1)

(Operation of Bumper Reinforcement 1)
Next, the operation of the bumper reinforcement 1 will be described with reference to FIGS.

As shown in FIG. 2A, when a load is applied to the bumper reinforcement 1 of the present embodiment in the collision direction indicated by the arrow, as shown in FIG. The constant cross-section webs 4 and 4 begin to buckle in the direction in which the middle portions thereof are separated from each other. However, since the variable cross-section web 5 on the inner side has a higher buckling strength than the constant cross-section webs 4 and 4, Do not start. For this reason, as shown in FIG. 2 (c), the rear flange 3 is plasticized so that the intermediate portion of the rear flange 3 protrudes in the collision direction before the inner cross-section web 5 buckles. First, accompanying this, the stay 8 is also deformed.

When a further load is applied, as shown in FIG. 2 (c), the buckling of the constant cross-section webs 4, 4 on the end side further progresses, and the variable cross-section web 5 on the inner side begins to buckle. Further, the rear flange 3 and the stay 8 are further deformed. In this way, the bending strength of the bumper reinforcement 1 is improved so as not to cause buckling of the variable cross section web 5 before the rear flange 3 is plasticized over its entire cross section.

On the other hand, as shown in FIG. 3 (a), when a load is applied to the conventional bumper reinforcement 31 in the collision direction indicated by the arrow, as shown in FIG. The constant cross-section webs 14 and 14 begin to buckle in the direction in which the intermediate portions of the constant cross-section webs 14 and 14 are separated from each other, and the inner constant cross-section web 15 also begins to buckle. After all the constant cross-section webs 14, 14, and 15 are buckled in this way, the force for maintaining the cross-sectional shape of the bumper reinforcement 31 is lost, and as shown in FIG. 31 collapse will proceed rapidly.

(Buckling strength simulation results)
Next, for the bumper reinforcement 1 shown in FIG. 2, the buckling strength of the variable cross-section web 5 disposed at the center of the hollow rectangular cross section was calculated. The calculation of the buckling strength was performed with the cross-sectional area of the variable cross section web 5 being constant.

FIG. 4 is a graph showing the simulation results of the buckling strength, wherein the vertical axis is the ratio of Pcr and Pcr0 (Pcr / Pcr0), and the horizontal axis is the thickness of the thickest part (maximum thickness) t2 and both ends. It is a ratio (t2 / t1) with the thickness t1 of the part. Here, Pcr is a buckling load, and Pcr0 is a buckling load when t2 / t1 = 1. In all calculations, the cross-sectional area of the web is the same.

From the graph of FIG. 4, when the cross-sectional area of the variable cross-section web 5 is a constant value, the buckling strength of the variable cross-section web 5 is a constant cross section where the wall thickness shown in FIG. 3 is constant (t3 / t3 = 1). It can be seen that the maximum is 1.4 times (t2 / t1 = 1.3) compared to the web 15. In addition, if the buckling strength of the variable cross-section web 5 is 20% or more and is in the range of 1.1 ≦ t2 / t1 ≦ 1.4, the bumper reinforcement 1 is kept to a minimum while the bumper reinforcement 1 is kept to a minimum. It can be seen that the bending strength of the reinforcement 1 can be improved.

Thus, since the cross-section web 5 disposed between the pair of flanges 2 and 3 has a shape in which the inner wall thickness is larger than the wall thickness at both ends thereof, the cross-sectional area is the same as this variable cross-section web 5. The buckling strength is higher than that of the constant cross-section web 15 having a constant thickness from one end to the other end. Thus, even if the thickness of the web is not increased uniformly from one end to the other, the web buckling strength is improved by making the inner thickness larger than the thickness at both ends of the web. Therefore, the bending strength can be improved while minimizing the increase in weight due to the thickening of the web.

In addition, the fact that the thickness t1 of the end portion of the cross section web 5 and the thickness t2 of the thickest portion satisfy the relationship of Formula 1 favorably improves the bending strength while minimizing an increase in weight. enable.

Moreover, the bumper reinforcement 1 having the above-described cross section web 5 can be attached to the vehicle body 100 of the automobile, thereby improving the safety of the passenger while contributing to the weight reduction of the vehicle.

(Outline of this embodiment)
As described above, the bending strength member (bumper reinforcement) 1 of the present embodiment is disposed so as to face each other in the load application direction to which a load is applied, and a pair of flanges each orthogonal to the load application direction. 2 and 3, and a web (variable cross-section web 5) which is disposed between the pair of flanges 2 and 3 in parallel to the load application direction and has a shape whose inner thickness is larger than the thickness at both ends thereof. Since the web disposed between the pair of flanges 2 and 3 has a shape in which the inner wall thickness is larger than the wall thickness at both ends, the web and the cross-sectional area are the same, and the wall thickness extends from one end to the other end. Has a higher buckling strength than a constant web. Therefore, without increasing the thickness of the web uniformly from one end to the other, by increasing the inner thickness than the thickness of both ends, the buckling strength of the web can be improved, The bending strength can be improved while minimizing the increase in weight due to the thickening of the web.

Further, as in the bending strength member 1 of this embodiment, the thickness t1 of the end portion of the web and the maximum thickness t2 do not satisfy the relationship of 1.1 ≦ t2 / t1 ≦ 1.4. The bending strength is preferably improved while minimizing the increase in weight.

Further, the bumper reinforcement 1 of the present embodiment comprising the bending strength member 1 described above can be attached to the vehicle body 100 of the automobile, thereby improving the safety of the occupant while contributing to weight reduction of the vehicle. .

[Second Embodiment]
Next, a bumper reinforcement (bending strength member) 21 according to the second embodiment of the present invention will be described with reference to FIGS.

(Configuration of Bumper Reinforcement 21)
The bumper reinforcement 21 in the present embodiment is made of a metal material such as aluminum or steel, and is integrally molded as a whole, and is supported by a pair of stays 8 and 8 as shown in FIG. It is attached in front of.

FIG. 5 shows a section of the bumper reinforcement 21 corresponding to the section taken along line AA of FIG. As shown in FIG. 5, the bumper reinforcement 21 has a cross-sectional shape in which the inside of a hollow rectangular cross section is partitioned vertically by a horizontal web, and specifically, it faces each other in the collision direction. Each having a front flange 2 and a rear flange 3 orthogonal to the collision direction, and three webs 4, 6, 6 arranged between the pair of flanges 2 and 3 in parallel to the collision direction. ing. The number of webs is not limited to three.

The front flange 2 is located on the upstream side in the collision direction indicated by the arrow, and the rear flange 3 is located on the downstream side in the collision direction with respect to the front flange 2. The front flange 2 and the rear flange 3 are connected to each other by three webs 4, 6, 6.

Of the three webs 4, 6, 6, two webs 6, 6 are respectively disposed between both end portions of the front flange 2 and both end portions of the rear flange 3 corresponding to the both end portions, respectively. The web 4 between the webs 6 and 6 is disposed between the longitudinal center portion of the front flange 2 and the longitudinal center portion of the rear flange 3. The webs 6 and 6 on the end portions are variable cross-section webs, and have a shape in which the inner wall thickness is larger than the wall thicknesses at both ends. On the other hand, the web 4 on the inner side is a constant cross-section web, and has a constant thickness from one end to the other end.

As shown in FIG. 5A, the constant cross-section web 4 has a length L in a direction parallel to the collision direction and a wall thickness t3 that is constant from one end to the other end. The cross-sectional shape of the constant cross-section web 4 is a rectangle. On the other hand, the variable cross-section web 6 has a length L in a direction parallel to the collision direction and a thickness that changes in that direction. Specifically, both end portions of the cross section web 6 have a thickness t1, and the central portion at a distance of L / 2 from both end portions is the thickest portion having the largest thickness t2. In addition, each variable cross-section web 6 has a center plane 6c that is a virtual cross section connecting the central point in the thickness direction at one end of the variable cross-section web 6 and the central point in the thickness direction at the other end. The thickness from the side surface (the surface on the side facing the mating cross-section web 6) 6a to the center plane 6c is the center plane from the outer surface (the surface on the opposite side to the surface facing the mating cross-section web 6) 6b. It has a shape larger than the wall thickness up to 6c.

The cross-sectional shape of the variable cross-section web 6 is asymmetrical when the direction orthogonal to the collision direction is left and right, and the inner side surface 6a has a large thickness from the inner side surface 6a to the central surface 6c. The outer surface 6b is a flat surface that suppresses the thickness from the outer surface 6b to the center surface 6c. Further, the cross-sectional shape of the variable cross-section web 6 is such that the thickness continuously increases from both end portions toward the central portion so that the central portion becomes the thickest thickest portion. ing.

On the other hand, as shown in FIG. 3 (a), in the conventional bumper reinforcement 31, all of the three webs have constant cross-sectional webs 14, 14 whose both end portions and central portion have a constant thickness t3. , 15. In other words, the conventional bumper reinforcement 31 has a pair of constant cross-sectional webs 14 and 14 having a constant thickness between the ends of the pair of flanges 2 and 3. The bumper reinforcement 1 of the form of this has the cross-section webs 6 and 6 between the edge parts of a pair of flanges 2 and 3 whose inner wall thickness is larger than the wall thickness of both ends. These variable cross-section webs 6 and 6 have a shape in which the inner wall thickness is larger than the thickness at both ends, so that the cross-sectional webs 14 and 14 having the same cross-sectional area as the variable cross-section webs 6 and 6 are higher. Has buckling strength. Further, the shape in which the thickness from the inner surface 6a to the central surface 6c is larger than the thickness from the outer surface 6b to the central surface 6c is such that the variable cross-section web 6 faces inward (approaching the opposite variable cross-section webs 6, 6). It is urged to buckle.

Here, the wall thickness t1 at both ends of the variable cross-section web 6 and the wall thickness t2 at the thickest part satisfy the above-mentioned formula 1. In other words, the wall thickness t1 at both ends of the variable cross-section web 6 and the wall thickness t2 at the thickest part are set so as to satisfy Expression 1. This makes it possible to favorably improve the bending strength while minimizing the increase in weight of the variable cross section web 6.

Further, as described above, each of the variable cross-section webs 6 has a shape that prompts them to buckle in the direction in which these variable cross-section webs 6 approach each other (inward). Therefore, as shown in FIG. The bent cross-section webs 6, 6 can fill the hollow portion surrounded by the pair of flanges 2, 3 and the respective webs 4, 6 to increase the toughness (stickiness) after the web buckling.

(Operation of bumper reinforcement 21)
Next, the operation of the bumper reinforcement 21 will be described with reference to FIG.

As shown in FIG. 5A, when a load is applied to the bumper reinforcement 21 in the collision direction indicated by the arrow, as shown in FIG. The buckling webs 6 and 6 on both end sides having a higher buckling strength than this, but have not yet started buckling. For this reason, the front flange 2 and the rear flange 3 begin to plasticize in the direction in which the center portion swells toward the stay 8 before the end-section side change webs 6 and 6 buckle. Deformation also occurs.

When a load is further applied, as shown in FIG. 5 (c), the buckling of the constant cross-section web 4 on the inner side further proceeds, and the variable cross-section webs 6 and 6 on the pair of end portions face inward. That is, the intermediate portion of the cross section web 6 starts to buckle in a direction approaching the counterpart cross section web 6 facing the intermediate section. The variable cross-section web 6 buckled in this way fills the hollow portion surrounded by the pair of flanges 2 and 3 and the webs 4 and 6, thereby toughening the bumper reinforcement 21 after the web buckling ( Tenacity) can be improved. Further, the pair of flanges 2 and 3 and the stay 8 are further deformed. In this way, the bending strength of the bumper reinforcement 21 is improved so that the variable cross-section web 6 does not buckle before the pair of flanges 2 and 3 are plasticized over the entire cross section.

(Bending strength simulation results)
Next, the bending strength of the bumper reinforcement was calculated by three-point bending analysis for the bumper reinforcement 21 of the present embodiment shown in FIG. 5 and the conventional bumper reinforcement 31 shown in FIG. . In the three-point bending analysis, the center of the front flange 2 was used as a loading point, and two locations of the rear flange 3 symmetrical to the loading point were used as fulcrums.

Here, the front flange 2 of each bumper reinforcement can be regarded as a beam supported near both ends. For this reason, the front flange 2 resists the load received by the bumper reinforcement at the time of collision by bending. Therefore, the greater the bending moment that can be borne by the bumper reinforcement, the higher the bending strength.

FIG. 6 is a graph showing a simulation result of bending strength, where the vertical axis represents the bending moment (kN · m) and the horizontal axis represents the indentation displacement (mm). From the graph of FIG. 6, the decrease in the bending strength after the bending moment reaches the peak is that the bumper reinforcement 21 having the cross-section web 6 is more than the bumper reinforcement 31 having no cross-section web 6. I understand that it is small. That is, in the bumper reinforcement 21 having the deformed cross-section web 6, the toughness (stickiness) after the web buckling is improved by buckling the respective cross-section webs 6 in the directions approaching each other (inward). I understand that. Thus, it can be seen that the bumper reinforcement 21 having the variable cross-section web 6 has higher energy absorption performance than the bumper reinforcement 31 not having the variable cross-section web 6.

In this way, the pair of variable cross-section webs 6, 6 disposed between the pair of flanges 2, 3 has a shape in which the wall thickness at both ends is larger than the inner wall thickness. The buckling strength is higher than that of the constant cross-section web 14 having the same area and a constant wall thickness from one end to the other end. Thus, even if the thickness of the web is not increased uniformly from one end to the other, the web buckling strength can be improved by making the inner thickness larger than the thickness at both ends. Therefore, the bending strength can be improved while minimizing the increase in weight due to the thickening of the web.

Each of the variable cross-section webs 6 and 6 has a wall thickness from the inner side surface 6a to the central surface 6c, which is a surface facing the counterpart cross-section web 6, from the opposite outer surface 6b to the central surface 6c. Therefore, the direction of buckling of these variable cross-section webs 6 and 6 can be inward, that is, the direction in which these variable cross-section webs 6 approach each other. The variable cross-section web 6 buckled in this direction can improve the toughness (stickiness) after the web buckling by filling the hollow portion surrounded by the pair of flanges 2 and 3 and the webs 4 and 6. .

(Outline of this embodiment)
As described above, the bending strength member (bumper reinforcement) 21 according to the present embodiment is disposed so as to face each other in the load application direction to which a load is applied, and a pair of flanges each orthogonal to the load application direction. 2 and 3 and a pair of flanges 2 and 3, each of which is arranged in parallel to the load application direction and has a pair of webs having a shape whose inner wall thickness is larger than the wall thickness at both ends (the variable cross-section webs 6 and 6 The thickness of each web from the inner surface 6a to the center surface 6c, which is the surface facing the other web, is the thickness from the outer surface 6b to the center surface 6c opposite to the inner surface 6a. It has a shape larger than the thickness.

As described above, the pair of webs disposed between the pair of flanges 2 and 3 have a shape in which the inner wall thickness is larger than the wall thicknesses at both ends thereof, and thus the cross-sectional area is the same as that of the web. From the web to the other end, it has a higher buckling strength than a web having a constant wall thickness. As described above, the web buckling strength can be improved by increasing the inner wall thickness from the both wall thicknesses without increasing the web wall thickness uniformly from one end to the other end. Therefore, the bending strength can be improved while minimizing the increase in weight due to the thickening of the web.

In addition, each web has a shape in which the thickness from the inner surface 6a facing the counterpart web to the center surface 6c is larger than the thickness from the opposite outer surface 6b to the center surface 6c. Will be prompted to buckle inward, that is, closer to the opponent's web. The web buckled in this direction can improve the toughness (stickiness) after web buckling by filling the hollow portion surrounded by the pair of flanges 2 and 3 and each web.

[Third Embodiment]
Next, a bumper reinforcement (bending strength member) 41 according to the third embodiment of the present invention will be described with reference to FIG.

(Configuration of Bumper Reinforcement 41)
The bumper reinforcement 41 in the present embodiment is made of a metal material such as aluminum or steel, and is entirely molded integrally, and is supported by a pair of stays 8 and 8 as shown in FIG. It is attached to the front of the vehicle body 100.

FIG. 7 shows a cross section of the bumper reinforcement 41 corresponding to the cross section taken along line AA of FIG. As shown in FIG. 7, the bumper reinforcement 41 has a hollow rectangular cross section, and the hollow portion is vertically partitioned by a horizontal web. Specifically, the bumper reinforcement 41 is disposed so as to be opposed to each other in the collision direction, and the bumper reinforcement 41 collides between the front flange 2 and the rear flange 3 that are orthogonal to the collision direction, and the pair of flanges 2 and 3. And three webs 5, 6, 6 arranged parallel to the direction. The number of webs is not limited to three.

The front flange 2 is located on the upstream side in the collision direction indicated by the arrow, and the rear flange 3 is located on the downstream side in the collision direction with respect to the front flange 2. The front flange 2 and the rear flange 3 are connected to each other by three webs 5, 6, 6.

Two of the three webs 5, 6, 6 are disposed between both ends of the front flange 2 and both ends of the rear flange 3 respectively corresponding to these both ends, The web 4 between 6 is arrange | positioned between the longitudinal direction center part of the front side flange 2, and the longitudinal direction center part of the rear side flange 3. FIG. The end side webs 6 and 6 are the variable cross-section webs described in the second embodiment, and the internal web 5 is the variable cross-section web described in the first embodiment.

That is, the bumper reinforcement 41 in the present embodiment is configured by a combination of the variable cross-section web 5 described in the first embodiment and the variable cross-section webs 6 and 6 described in the second embodiment. The Other configurations are the same as those in the first embodiment and the second embodiment, and thus description thereof is omitted.

(Outline of this embodiment)
As described above, the bending strength member (bumper reinforcement) 41 of the present embodiment is disposed so as to face each other in the load application direction to which a load is applied, and a pair of flanges each orthogonal to the load application direction. 2 and 3 and one or more internal webs (variable cross-sections) disposed between the inner sides of the pair of flanges 2 and 3 in parallel to the load application direction and having a shape whose inner thickness is larger than the thickness at both ends. Between the ends of the web 5) and the pair of flanges 2 and 3, the webs on the side of the pair of end portions, each of which is arranged in parallel to the load application direction and has a shape whose inner thickness is larger than the thickness of both ends. (Varied cross-section webs 6 and 6), and the thickness of the web on each end side from the inner side surface 6a facing the opposite end side web to the center surface 6c is opposite to the inner side surface 6a. From the outer side 6b to the center plane 6c Having a wall shape larger than the thickness of at.

According to said structure, since each web arrange | positioned between a pair of flanges 2 and 3 has a shape where inner wall thickness is larger than the wall thickness of the both ends, this web and cross-sectional area are the same, It has a buckling strength higher than that of a web having a constant wall thickness from one end to the other end. As described above, the web buckling strength can be improved by increasing the inner wall thickness from the both wall thicknesses without increasing the web wall thickness uniformly from one end to the other end. Therefore, the bending strength can be improved while minimizing the increase in weight due to the thickening of the web.

Each end side web has a wall thickness from the inner side surface 6a to the center surface 6c facing the other end side web, and from the outer side surface 6b to the center surface 6c opposite to the inner side surface 6a. Since it has a shape larger than the thickness, it is urged to buckle inward, that is, toward the web on the other end side. The web buckling in this direction can improve the toughness (stickiness) after the web buckling by filling the hollow portion surrounded by the pair of flanges 2 and 3 and each web.

[Fourth Embodiment]
Next, a bumper reinforcement (bending strength member) 121 according to the fourth embodiment of the present invention will be described with reference to FIGS.

(Configuration of Bumper Reinforcement 121)
The bumper reinforcement 121 in the present embodiment is made of a metal material such as aluminum or steel, and is entirely molded integrally, and is supported by a pair of stays 8 and 8 as shown in FIG. It is attached to the front of the vehicle body 100.

FIG. 8 shows a cross section of the bumper reinforcement 121 corresponding to the cross section taken along line AA of FIG. As shown in FIG. 8, the bumper reinforcement 121 has a hollow rectangular cross section, and the hollow portion is vertically partitioned by a horizontal web. Specifically, the bumper reinforcement 121 is disposed so as to face each other in the collision direction, and the bumper reinforcement 121 collides between the front flange 2 and the rear flange 3 and the pair of flanges 2 and 3 which are orthogonal to the collision direction. And three webs 4, 11, 11 arranged parallel to the direction. The number of webs is not limited to three.

The front flange 2 is located on the upstream side in the collision direction indicated by the arrow, and the rear flange 3 is located on the downstream side in the collision direction with respect to the front flange 2. The front flange 2 and the rear flange 3 are connected to each other by three webs 4, 11, 11.

Of the three webs 4, 11, 11, two webs 11, 11 are respectively disposed between both ends of the front flange 2 and both ends of the rear flange 3 facing the both ends. . Further, the web 4 is disposed between the longitudinal center portion of the front flange 2 and the longitudinal center portion of the rear flange 3. The webs 11, 11 on each end side are variable cross-section webs and have a shape in which the inner wall thickness is larger than the wall thickness at both ends. On the other hand, the inner web 4 is the constant cross-sectional web described in the first embodiment, and has a constant thickness from one end to the other end.

As shown in FIG. 8, the constant cross-section web 4 has a length L in a direction parallel to the collision direction and a wall thickness t3 that is constant from one end to the other end. The cross-sectional shape of the constant cross-section web 4 is a rectangle. On the other hand, the variable cross-section web 11 has a length L in a direction parallel to the collision direction and a thickness that changes in the longitudinal direction. Specifically, both end portions of the variable cross-section web 11 have a thickness t1, and the center portion at a distance of L / 2 from both end portions is the thickest portion having the largest thickness t2. However, the apparent thickness t2 of the thickest portion includes a depth c of a notch portion 11d described later, and the actual thickness t4 is smaller by the depth c.

Each variable cross-section web 11 has an inner surface 11a that is a surface facing the counterpart variable cross-section web 11, and an outer surface 11b opposite to the inner surface 11a, and the wall thickness from the inner surface 11a to the center surface 11c is It has a shape larger than the thickness from the outer surface 11b to the center surface 11c. Here, the center plane 11c is a virtual cross section that connects the center point in the thickness direction at one end of the variable cross-section web 11 and the center point in the thickness direction at the other end.

The cross-sectional shape of the variable cross-section web 11 is asymmetrical when the direction orthogonal to the collision direction is left and right. The inner surface 11a is a convex surface that swells inward so as to increase the thickness from the inner surface 11a to the central surface 11c, and the outer surface 11b suppresses the thickness from the outer surface 11b to the central surface 11c. It is a plane. Moreover, the cross-sectional shape of the variable cross-section web 11 is a shape in which the thickness continuously increases from both end portions toward the central portion so that the central portion becomes the thickest thickest portion. .

Further, a cutout portion 11 d is formed on the outermost surface 11 b of the thickest portion of the variable cross section web 11. As shown in FIG. 9A, the notch portion 11d has a depth c, and the actual thickness t4 of the thickest portion excluding the depth c of the notch portion 11d is greater than the apparent thickness t2. Is also small. The variable cross-section web 11 is different from the variable cross-section web 6 shown in FIG. 9B in that it has a notch 11d.

Here, in the variable cross-section web 11, the thickness t1 at both ends, the apparent thickness t2 of the thickest part including the depth c of the notch 11d, and the depth c of the notch 11d are as follows: The following formula 2 is satisfied. In other words, the thickness t1 of the both end portions of the variable cross section web 11, the apparent thickness t2 of the thickest portion, and the depth c of the notch portion 11d are set so as to satisfy Expression 2. This makes it possible to suitably improve the bending strength while minimizing the increase in weight.

1.1 ≦ (t2-c) /t1≦1.4 ... (Formula 2)

The apparent thickness t2 of the thickest part including the depth c of the notch part 11d satisfies the above formula 1.

As described above, the variable cross-section webs 11 and 11 have a shape in which the inner wall thickness is larger than the wall thicknesses at both ends, so that the constant cross-section webs 14 and 14 having the same cross-sectional area as this (see FIG. 3A). ) And a wall thickness from the inner surface 11a to the central surface 11c is larger than a wall thickness from the outer surface 11b to the central surface 11c. You are prompted to buckle inward (inward). The variable cross-section webs 11 and 11 that buckle in this direction improve the toughness (stickiness) after the web buckling by filling the hollow portion surrounded by the pair of flanges 2 and 3 and the webs 4 and 11. Can be made.

Further, the notched portion 11d formed on the outer side surface 11b of the variable cross-section webs 11 and 11 can also promote the buckling of the variable cross-section webs 11 and 11 inwardly. This can contribute to the improvement of tenacity.

(Displacement simulation results)
For the bumper reinforcement 121 of the present embodiment shown in FIG. 8 and the bumper reinforcement 21 shown in FIG. 5, the depth c of the notch 11d and the displacement amount due to the inward buckling of the web The relationship was calculated.

FIG. 10 is a graph showing a simulation result of the displacement amount. U / U0 on the vertical axis represents the displacement amount U of the bumper reinforcement 121 of the present embodiment having the notch 11d (see FIG. 9A). Is divided by the amount of displacement U0 (see FIG. 9B) of the bumper reinforcement 21 having no notch. The horizontal axis represents a value obtained by dividing the depth c of the notch 11d by the thickness t2 of the thickest part including the depth c of the notch 11d.

From the graph of FIG. 10, it can be seen that the notch 11d greatly increases the amount of displacement due to the inward buckling of the web even if the depth c is slight. For example, even if the value of c / t2 is 0.15, the amount of displacement U of the bumper reinforcement 121 having the variable cross-section web 11 having the notch 11d is the bumper having the variable cross-section web 6 having no notch. The displacement amount U0 of the reinforcement 21 is 1.6 times.

That is, in the bumper reinforcement 121 having the variable cross-section web 11 in which the notch portion 11d is formed, each variable cross-section web 11 is likely to buckle in a direction (inward) approaching the counterpart variable cross-section web 11. Recognize. This is because the bumper reinforcement 121 having the variable cross-section web 11 having the notched portion 11d has a toughness after web buckling (bumper reinforcement 21 having the variable cross-section web 6 not having the notched portion). It means that tenacity can be improved.

As described above, the pair of variable cross-section webs 11 and 11 disposed between the pair of flanges 2 and 3 have a shape in which the inner wall thickness is larger than the wall thickness at both ends thereof. The buckling strength is higher than that of the constant cross-section web 14 (see FIG. 3A) having the same area and a constant thickness from one end to the other end. That is, even if the thickness of the web is not increased uniformly from one end to the other, the web buckling strength can be improved by increasing the thickness inside the thickness at both ends. Therefore, the bending strength can be improved while minimizing the increase in weight due to the thickening of the web.

Further, each of the variable cross-section webs 11 and 11 has a wall thickness from the inner surface 11a to the central surface 11c, which is a surface facing the counterpart variable cross-section web 11, from a wall thickness from the outer surface 11b to the central surface 11c. Therefore, the direction of buckling of each of the cross-section webs 11 and 11 can be inward, that is, the direction approaching the counterpart cross-section web 11. Since the variable cross-section web 11 buckled in this direction can fill the hollow portion surrounded by the pair of flanges 2 and 3 and each web, the toughness (stickiness) after web buckling can be improved. .

Further, the notched portion 11d provided on the outermost surface 11b of the thickest portion of each variable cross-section web 11, 11 can also easily buckle in the direction in which the cross-section web 11, 11 approaches each other. Each of the deformed cross-section webs 11 and 11 is urged to fill a hollow portion surrounded by the pair of flanges 2 and 3 and the webs 4 and 11 to further improve toughness (stickiness) after web buckling. Can do.

Further, the thickness t1 of the end of the variable cross section web 11, the apparent thickness t2 of the thickest portion (including the depth c of the notch 11d), and the depth c of the notch 11d are expressed by the following equation (2). Since the relationship is satisfied, the bending strength can be suitably improved while minimizing the increase in weight.

Other configurations are the same as those of the second embodiment, and thus description thereof is omitted.

(Outline of this embodiment)
As described above, in the bending strength member (bumper reinforcement) 121 of the present embodiment, the notch portion 11d is provided on the outermost surface 11b of the thickest portion of each web (the variable cross section web 11). ing. This notch portion 11d encourages the web to buckle in the direction in which the webs approach each other, thereby promoting the buckling of the hollow portion surrounded by the pair of flanges 2 and 3 and each web. Thus, the toughness (stickiness) after web buckling can be further improved.

Further, the thickness t1 of the end portion of the web, the thickness t2 of the thickest portion, and the depth c of the notch portion 11d satisfy the relationship of 1.1 ≦ (t2-c) /t1≦1.4. The bending strength can be suitably improved while minimizing the increase in weight.

(Modification)
As mentioned above, although main embodiment of this invention was described, this is an illustration and is not the meaning which limits this invention to the said embodiment, The design of a concrete structure etc. can be changed suitably. Further, the actions and effects described in the embodiments of the invention only list the most preferable actions and effects resulting from the present invention, and the actions and effects according to the present invention are described in the embodiments of the present invention. It is not limited to what was done.

For example, in each embodiment, the cross-sectional shape of the bumper reinforcements 1, 21, 41, 121 is a shape in which the inner space is partitioned vertically by a single horizontal web based on a hollow rectangular cross-section. However, based on the B shape, E shape, and hollow rectangular cross section, the inner space is divided into three or more pieces in the vertical direction by a plurality of horizontal webs, or simply a hollow rectangular cross section shape. Also good.

Further, the bumper reinforcement according to the present invention is the same as the bumper reinforcement 51 shown in FIG. 11A in which the variable cross-section web 5 in the bumper reinforcement 1 according to the first embodiment is used in the second embodiment. It may be replaced with the variable cross-section web 6 of the form. Also in this bumper reinforcement 51, the bending strength can be improved while minimizing the increase in weight due to the thickening of the web.

Further, the bumper reinforcement according to the present invention is the same as the bumper reinforcement 61 shown in FIG. 11B, in which the variable cross-section web 5 in the bumper reinforcement 1 according to the first embodiment is changed to the variable cross-section web 7. It may be replaced with. The variable cross-section web 7 has a length L in a direction parallel to the collision direction and a thickness that changes in the longitudinal direction. Specifically, both end portions of the cross section web 7 have a thickness t1, and a portion located at a distance of L / 4 from the one end portion constitutes the thickest portion having the maximum thickness t2. The cross-sectional shape of the variable cross-section web 7 is bilaterally symmetrical when the direction orthogonal to the collision direction is set to the left and right, and from both ends to the center so that the thickness of the center is the thickest. The shape is such that the wall thickness increases continuously. Also in the bumper reinforcement 61 having such a configuration, the bending strength can be improved while minimizing the increase in weight due to the thickening of the web.

In addition, the bumper reinforcement according to the present invention, like the bumper reinforcement 71 shown in FIG. 12 (a), is provided with two fixed members disposed between the pair of flanges 2 and 3 and their ends. Two variable cross-section webs 5, which are arranged between the inner side portions of the pair of flanges 2, 3 between the cross-section webs 4, 4 and between the constant cross-section webs 4, 4. 5 may be included. Also in this bumper reinforcement 71, the bending strength can be improved while minimizing the increase in weight due to the thickening of the web.

Further, the bumper reinforcement according to the present invention is similar to the bumper reinforcement 81 and 91 shown in FIGS. 12B and 12C, respectively, and the bumper reinforcement shown in FIG. The two variable cross-section webs 5 and 5 of 71 may be respectively replaced with variable cross-section webs 6 and 6 whose cross-sectional shapes are asymmetric. In these bumper reinforcements 81 and 91 as well, the bending strength can be improved and the toughness after the web buckling can be improved while minimizing the increase in weight due to the thickening of the web.

Further, the bumper reinforcement according to the present invention is similar to the bumper reinforcement 101 shown in FIG. 13A, in which the variable cross-section web 5 in the bumper reinforcement 1 according to the first embodiment is changed to the variable cross-section web 9. It may be replaced with. The variable cross-section web 9 has a length L in a direction parallel to the collision direction and a thickness that changes in the longitudinal direction. Specifically, both end portions of the variable cross-section web 9 have a thickness t1, and a central portion having a distance of L / 2 from both end portions constitutes the thickest portion having the maximum thickness t2. The cross-sectional shape of the variable cross-section web 9 is symmetrical when the direction orthogonal to the collision direction is left and right, and is a portion (boundary portion) located at a predetermined distance (for example, L / 3) from both ends. Up to 9a, a portion having a constant thickness t1 and sandwiched between the two boundary portions 9a is arranged from each boundary portion 9a to the central portion so that the central portion becomes the thickest portion having the maximum thickness. It has a shape in which the wall thickness continuously increases. Also in this bumper reinforcement 101, the bending strength can be improved while minimizing the increase in weight due to the thickening of the web.

Further, the bumper reinforcement according to the present invention is similar to the bumper reinforcement 111 shown in FIG. 13 (b), in which the variable cross-section web 5 in the bumper reinforcement 1 according to the first embodiment is replaced with the variable cross-section web 10. It may be replaced with. The variable cross-section web 10 has a length L in a direction parallel to the collision direction and a thickness that changes in the longitudinal direction. Specifically, both end portions of the variable cross-section web 10 have a thickness t1, and the central portion at a distance of L / 2 from both end portions constitutes the thickest portion having the maximum thickness t2. Specifically, the cross-sectional shape of the variable cross-section web 10 is symmetrical when the direction orthogonal to the collision direction is left and right, and is a portion (boundary) located at a predetermined distance (for example, L / 3) from both ends. Part) 10a has a constant thickness t1, and the portion sandwiched between the two boundary portions 10a has a two-stage shape having the maximum thickness t2. Also in this bumper reinforcement 111, the bending strength can be improved while minimizing the increase in weight due to the thickening of the web.

Further, the bumper reinforcement according to the present invention is similar to the bumper reinforcement 131 shown in FIG. 14 in that the constant cross-section web 4 in the bumper reinforcement 121 according to the fourth embodiment is replaced by the first embodiment. It may be replaced with the variable cross-section web 5. Also in the bumper reinforcement 131, the notched portions 11d formed in the variable cross-section webs 11 and 11 make it easy to buckle the variable cross-section webs 11 and 11 in a direction approaching each other.

Further, in the bumper reinforcement according to each of the above embodiments, the pair of flanges 2 and 3 and the web may not be molded integrally, or may be separate. An object of the present invention is to provide a bending strength member and a bumper reinforcement capable of improving bending strength while minimizing an increase in weight.

As described above, according to the present invention, a bending strength member and a bumper reinforcement capable of improving the bending strength while minimizing an increase in weight are provided.

The bending strength member according to the present invention is disposed so as to oppose each other in a load application direction to which a load is applied, each of which is perpendicular to the load application direction, and the load application direction between the pair of flanges And a web having a shape in which the thickness of the inner portion is larger than the thickness of both ends. Since the thickness of the inner side of the web is larger than the thickness of the both ends, the web has a higher seating in the load application direction than the web having the same cross-sectional area as the web and having a constant thickness from one end to the other end. Has bending strength. In this way, the web buckling strength can be improved by increasing the thickness on the inner side than the thickness at both ends, without increasing the thickness of the web uniformly from one end to the other. The bending strength can be improved while minimizing the increase in weight due to the thickening of the web.

Further, the bending strength member according to the present invention is disposed so as to face each other in the load application direction to which a load is applied, and each of the pair of flanges orthogonal to the load application direction, and between the pair of flanges, respectively. Are arranged in parallel with the load application direction, and have a pair of webs having a shape whose inner wall thickness is larger than the wall thickness at both ends, and each web is a surface on the side facing the counterpart web. The thickness from the inner surface to the center surface is larger than the thickness from the outer surface to the center surface, which is the surface opposite to the inner surface, and the center surface is the thickness of one end of the web. It is a surface connecting the center point in the direction and the center point in the thickness direction at the other end.

Each of the pair of webs disposed between the pair of flanges in the bending strength member has a shape in which the inner wall thickness is larger than the wall thickness at both ends thereof. It has a higher buckling strength than a web having a constant thickness across the other end. In this way, the web buckling strength can be improved by increasing the thickness on the inner side of the thickness at both ends without increasing the thickness of the web uniformly from one end to the other. Therefore, the bending strength can be improved while minimizing the increase in weight due to the thickening of the web.

In addition, each web has a shape in which the thickness from the inner surface to the center surface facing the counterpart web is larger than the thickness from the outer surface to the center surface opposite to the inner surface. Are likely to buckle toward each other, that is, inward. Thus, since the web buckled inward can fill the hollow portion surrounded by the pair of flanges and the webs, the toughness (stickiness) after the web buckling can be improved.

Further, in the bending strength member of the present invention, a notch portion may be provided on the outer side surface of the thickest portion having the maximum thickness in each web. This notch urges the web to buckle in the direction in which the webs approach each other, thereby making it easier for the buckled web to fill the hollow portion surrounded by the pair of flanges and each web, The toughness (stickiness) after bending can be further improved.

In the bending strength member of the present invention, the thickness t1 of the end portion of the web, the thickness t2 of the thickest portion, and the depth c of the notch portion are 1.1 ≦ (t2-c) / It is more preferable to satisfy the relationship of t1 ≦ 1.4. This makes it possible to suitably improve the bending strength of the bending strength member while minimizing the increase in weight.

Further, the bending strength member according to the present invention is disposed so as to face each other in the load application direction to which a load is applied, and each of the pair of flanges orthogonal to the load application direction and both ends of the pair of flanges. One or more inner webs arranged in parallel to the load application direction between the inner portions and having a shape in which the inner thickness is larger than the thickness at both ends, and the ends of the pair of flanges A pair of end-side webs, each of which is arranged so as to be parallel to the load application direction and has a shape whose inner thickness is larger than the thickness of both ends, and each of the end portions The side web has a wall thickness from the inner surface that is the surface facing the other end side web to the center surface, more than the wall thickness from the outer surface that is the surface opposite to the inner surface to the center surface. Also has a large shape, the center Is a surface connecting the middle point of the thickness direction of the central point and the other end in the thickness direction of one end of the web.

Each of the webs arranged between the pair of flanges in this bending strength member has a shape in which the inner wall thickness is larger than the wall thickness at both ends thereof. It has a higher buckling strength than a web with a constant wall thickness across the edges. In this way, the web buckling strength can be improved by increasing the thickness on the inner side of the thickness at both ends without increasing the thickness of the web uniformly from one end to the other. Therefore, the bending strength can be improved while minimizing the increase in weight due to the thickening of the web.

In addition, each end side web has a shape in which the thickness from the inner side surface to the center plane is larger than the thickness from the outer side surface to the center plane, so these end side webs buckle inward toward each other. Cheap. Thus, since the end side web which buckled inward can fill the hollow part enclosed by a pair of flange and each web, it can improve the toughness (tensile strength) after web buckling. it can.

Further, in the bending strength member according to the present invention, a notch portion may be provided on the outer surface side of the thickest portion having the maximum thickness in each end side web. This notch part buckles in the direction in which the end side webs approach each other and promotes filling of the hollow part surrounded by the pair of flanges and each web, further improving the toughness (stickiness) after web buckling Can be made.

In the bending strength member of the present invention, the thickness t1, the maximum thickness t2, and the depth c of the notch are 1.1 ≦ (t2c) / t1 ≦. It is more preferable to satisfy the relationship of 1.4. This makes it possible to favorably improve the bending strength while minimizing the increase in weight.

In the bending strength member of the present invention, it is more preferable that the thickness t1 of the end portion of the web and the thickness t2 of the thickest portion satisfy a relationship of 1.1 ≦ t2 / t1 ≦ 1.4. preferable. This makes it possible to favorably improve the bending strength while minimizing the increase in weight.

Also, the bumper reinforcement according to the present invention including the bending strength member described above can be attached to the vehicle body of the automobile, thereby improving the safety of the passenger while contributing to the weight reduction of the vehicle.

Claims (9)

1. A pair of flanges arranged to oppose each other in a load application direction to which a load is applied, each orthogonal to the load application direction;
   A bending strength member comprising: a web having a shape that is disposed between the pair of flanges so as to be parallel to the load application direction and has a larger inner thickness than the thickness of both ends.
2. A pair of flanges arranged to oppose each other in a load application direction to which a load is applied, each orthogonal to the load application direction;
   A pair of webs arranged between the pair of flanges so as to be parallel to the load application direction and having a shape having a larger inner thickness than the thickness of both ends, and each web has its counterpart The thickness from the inner surface that is the surface facing the web to the center surface is larger than the thickness from the outer surface that is the surface opposite to the inner surface to the center surface, A center plane is a bending strength member which is a surface which connects the center point of the thickness direction of one end of the said web, and the center point of the thickness direction of the other end.
3. The bending strength member according to claim 2, wherein a notch portion is provided on an outer surface of the thickest portion having the maximum thickness in each of the webs.
4. 1.1≤ (t2-c) /t1≤1.4 where t1 is the thickness of the end of the web, t2 is the thickness of the thickest part, and c is the depth of the notch. The bending strength member according to claim 3, wherein the relationship is established.
5. A pair of flanges arranged to oppose each other in a load application direction to which a load is applied, each orthogonal to the load application direction;
   One or more inner webs that are arranged between the inner portions of both ends of the pair of flanges so as to be parallel to the load application direction and have a shape in which the inner thickness is larger than the thickness of both ends. When,
   Between the ends of the pair of flanges, a pair of end-side webs that are arranged so as to be parallel to the load application direction and have a shape whose inner thickness is larger than the thickness at both ends, Each end side web has a wall thickness from the inner surface to the center surface on the side facing the other end side web from the outer side surface that is the surface opposite to the inner side surface. A bending strength member having a shape larger than the thickness up to the central plane, wherein the central plane is a plane connecting a central point in the thickness direction at one end of the web and a central point in the thickness direction at the other end.
6. The bending strength member according to claim 5, wherein a notch portion is provided on an outer surface side of a thickest portion having a maximum thickness in each end side web.
7. 1.1 ≦ (t2−c) / t1 ≦ 1 where t1 is the thickness of the web on the end side, t2 is the thickness of the thickest portion, and c is the depth of the notch. The bending strength member according to claim 6, wherein a relationship of .4 is established.
8. The bending strength member according to claim 1, wherein a relationship of 1.1 ≦ t2 / t1 ≦ 1.4 is established, where t1 is a thickness of an end portion of the web and t2 is a maximum thickness.
9. Bumper reinforcement including the bending strength member according to any one of claims 1 to 8.

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