JP2006315575A - Bumper stay, and bumper device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an aluminum stay capable of absorbing the energy during the collision without increasing the cost and the weight, and a bumper device using the aluminum stay. <P>SOLUTION: The stay 1 arranged between a bumper reinforcing member 2 of a vehicle body and a side member 3 consists of an aluminum alloy extruded hollow structural angle with its extrusion direction being the vertical direction of the vehicle body has a substantially rectangular section consisting of a pair of longitudinal wall-like flanges 5a, 5b, and longitudinal wall-like ribs 6a, 6b to connect the flanges to each other, and has expansion flanges 4a, 4b, 4c, 4d expanded in the width direction of the vehicle body from the longitudinal wall-like ribs on either/each of the longitudinal wall-like flanges 5a, 5b. The stay is joined with either/each of the bumper reinforcing member 2 and the side member 3 on the expansion flanges. An energy absorption part 8 having a substantially hat-shaped section protruded in the longitudinal direction of the vehicle body within the substantially rectangular section is formed on at least one of the flanges 5a, 5b. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an aluminum alloy bumper stay disposed between a bumper reinforcing member and a side member of an automobile body and capable of absorbing collision energy at the time of a collision, and a bumper apparatus having the bumper stay disposed therein.

  Bumper reinforcements (also called bumper reinforcements or bumper armatures) as strength reinforcements are provided inside bumpers attached to the front end (front) and rear end (rear) of automobile bodies. .

  As a crash box (impact energy absorber) that can be plastically deformed between the bumper reinforcement of the vehicle body and the side member (side frame) on the vehicle body side in order to mitigate the impact on the passenger at the time of the vehicle body collision, An example in which a bumper stay (hereinafter simply referred to as stay) is interposed has been proposed. This stay originally has a role as a support member (body connection member) from the rear surface of the bumper reinforcement.

Conventionally, various types of stays using extruded hollow shapes have been proposed and adopted as aluminum alloy stays instead of steel for weight reduction. Stays made of this aluminum alloy extruded hollow shape (hereinafter also simply referred to as aluminum stays) are roughly classified into the following two types.
1. A stay that longitudinally crushes in the extrusion direction of the extruded profile with the longitudinal direction of the vehicle (the longitudinal direction of the vehicle) as the extrusion direction (hereinafter referred to as the longitudinal crush-type stay)
2. A stay that laterally collapses in the cross-sectional direction of the extruded profile (hereinafter referred to as a laterally collapsed stay), with the vehicle body left-right direction (vehicle width direction) or vehicle body vertical direction as the extrusion direction.

  The vertical crushing type stay can have a cross-sectional structure that is perpendicular to the collision direction, and the weight can be reduced as compared with the lateral crushing type stay in consideration of obtaining the same strength. However, it is necessary to join the mounting flange for joining the rear surface (back surface) or side member of the bumper reinforcing material to the extruded shape of the stay body by welding or the like. For this reason, there is a problem that the manufacturing cost of the stay itself increases.

  On the other hand, the lateral crush type stay can be formed by integrally extruding in advance together with the shape of the stay body together with the flange corresponding to the mounting surface. Then, by cutting the extruded shape member into a certain length in the longitudinal direction, it is possible to obtain a predetermined stay shape, and to obtain a lower cost product as compared with the longitudinal crush stay. Can do.

  Various types of stays have been proposed as the above-described lateral collapse type stays, in which the cross-sectional shape of the stay main body has a substantially mouth-shaped or rice-shaped cross-sectional shape and is provided with a flange that is shaped to fit to other parts. (See Patent Documents 1 and 2).

Also, the vertical wall-shaped ribs that make up the lateral collapse type stay are thinned only on the front side of the vehicle body. After the thin wall portion is first buckled, the thick wall portion on the rear side of the vehicle body is buckled and deformed to absorb energy in two stages. An example to be attempted has also been reported (see Patent Document 3). Further, a vertical wall-shaped middle rib that reinforces deformation of the ribs of the lateral crush type stay includes an intersection of the vehicle body front side flange and the rib or the vicinity thereof, and an intersection of the vehicle body rear side flange and the rib or the There is also an example in which neighbors are connected diagonally and extended obliquely (see Patent Document 4). There is also an example in which a rubber energy absorbing member is inserted into the lateral crushing stay (see Patent Document 5). Further, there is an example in which a vertical crushing stay is inserted into the lateral crushing stay to achieve both attachment performance and energy absorption characteristics (see Patent Document 6).
JP 2001-294106 A (full text) JP-A-6-227333 (full text) JP 2002-12103 A (full text) Japanese Patent Laying-Open No. 2005-14836 (full text) JP 2001-58549 A (full text) JP 2002-12107 A (full text)

  In recent years, in accordance with the strengthening of collision safety standards, high energy absorption performance has been required for bumper stays for automobiles. For this reason, it has been desired that the aluminum stay also be deformed below a predetermined load limit and efficiently absorb the collision energy within a limited deformation stroke.

  When the deformation load of the aluminum stay exceeds the load limit (when the maximum load at the time of crushing is too high), the parts such as the side member constituting the vehicle body are deformed earlier than the aluminum stay. Further, even when energy cannot be absorbed within a limited stroke, there is a problem that parts such as a side member located behind the member are naturally damaged.

  The structure that absorbs energy most ideally is a structure in which the maximum load at the time of crushing does not exceed the target requirement, and the crushing deformation proceeds without load fluctuation (without lowering). In this regard, in the lateral crushing type aluminum stay, a pair of flanges extending in the longitudinal direction of the vehicle body (the longitudinal direction of the vehicle body), extending in the vehicle body width direction and spaced apart in the longitudinal direction of the vehicle body We are connected to each other. For this reason, in a lateral crushing type aluminum stay, at the time of a collision, the vertical wall-shaped rib in the aluminum stay is bent and deformed, so that the collision energy is mainly absorbed. Therefore, it is most desirable for the lateral crushing type aluminum stay to obtain a stable deformation load in the bending deformation of the vertical wall rib.

  On the other hand, for transportation equipment such as automobiles, lighter parts are desired from the viewpoint of protecting the global environment. For this reason, the aluminum stay is also made of a high-strength material among aluminum alloys such as 6000 series or 7000 series in order to obtain a thin wall (light weight) and a high deformation load. Although these materials have a high yield strength, the amount of work hardening in the plastic region is small.

  However, when such a high-strength material is applied to the lateral crushing type aluminum stay having the extrusion direction in the lateral direction of the vehicle body (the vehicle body width direction) or the vehicle body vertical direction, in the types such as Patent Documents 1 and 2, As the crushing progresses, there is a problem that the deformation load decreases and the energy absorption amount decreases.

  The cause of this will be briefly described below. Since the high-strength material has a small amount of work hardening in the plastic region, it hardly increases after the bending moment applied to the bending deformation part of the vertical ribs reaches the total plastic moment Mp (material proof stress σy × total plasticity coefficient Zp). . The deformation load P is proportional to the bending moment divided by the vehicle width direction distance L (the vehicle width direction distance from the front end of the vehicle body to the bending deformation portion) of the vertical wall-shaped rib. That is, as the crushing deformation progresses, the bending deformation portion of the vertical wall-shaped rib spreads in the vehicle body width direction, and the bending moment generated in the bending deformation portion does not increase, so the deformation load P decreases. Further, it can be said that as the stay length becomes longer, L becomes larger and the deformation load is significantly reduced.

  In order to avoid this, if the thickness of the vertical wall ribs or the like is increased, the maximum load increases, and there is a problem that the side members on the rear side of the stay are damaged. In this regard, for example, if the difference between the thin portion and the thick portion is small as in Patent Document 3, the target two-stage buckling mode in Patent Document 3 does not occur. On the other hand, when the difference is increased, there is a problem that the difference in deformation load in the buckling deformation of the thin wall portion and the thick wall portion becomes large, and as a result, there is a problem that a great effect cannot be obtained. Lack of sex.

  In addition, the example in which the inclined wall that reinforces the deformation of the ribs in Patent Document 4 is also a proposal for preventing the stay from collapsing mainly due to a collision, and is not intended to improve the energy absorption characteristics. Absent. In addition, the means and mechanism for increasing the wall thickness are the same, and the maximum load is increased, causing a problem such as damage to the side member on the rear side of the stay. Moreover, the load drop after the maximum load is large.

  Furthermore, in the example in which a rubber energy absorbing member is inserted into the lateral crushing type stay in Patent Document 5 or the vertical crushing type stay in Patent Document 6 is inserted, an attempt is made to achieve both mounting performance and energy absorption characteristics. However, in both cases, there is a problem that due to the insertion of a new member, the manufacturing cost of the stay increases and the practicality is lacking.

  Therefore, in these conventional lateral collapse type stays, it is difficult to achieve both reduction in the maximum load and increase in the amount of energy absorption by suppressing a decrease in load after the maximum load. In other words, there is a big problem that the characteristics such as the maximum load of the aluminum stay and the energy absorption characteristic cannot be adjusted particularly corresponding to the offset barrier collision.

  In view of this point, an object of the present invention is to provide a bumper stay in which an aluminum stay can absorb energy at the time of collision without increasing the manufacturing cost, and a bumper apparatus in which the bumper stay is arranged.

  In order to achieve the above object, the gist of the bumper stay of the present invention is a bumper stay disposed between a bumper reinforcing member and a side member of an automobile body, and the bumper stay is an aluminum alloy whose vertical direction is the extrusion direction of the vehicle body. A pair of vertical wall-shaped flanges, which are made of extruded hollow shapes and extend in the vehicle body width direction and are spaced apart from each other in the vehicle body longitudinal direction, and a vertical wall that extends in the vehicle body longitudinal direction and connects the pair of flanges A rib having a substantially rectangular cross-sectional shape, and a protruding flange that protrudes in the vehicle width direction side of the vertical wall-shaped rib on either or both of the vertical wall-shaped flanges. In the overhang flange, either or both of the bumper reinforcing member and the side member are joined, and at least one of the flanges is within the substantially rectangular cross section. It is that the energy absorbing portion having a substantially hat-shaped cross section projecting in body length side direction are formed.

  In order to achieve the above object, the gist of the bumper stay device of the present invention is that the bumper stay according to any one of the above gist and a preferred mode described later is disposed between the bumper reinforcing material of the automobile body and the side member. .

  In the present invention, in the lateral crushing type aluminum stay in which the vertical direction of the vehicle body is the extrusion direction, an energy absorbing portion having a substantially hat-shaped cross-sectional shape protruding in the longitudinal direction of the vehicle body in the substantially rectangular cross section is formed on at least one of the flanges. It is characterized by that.

  Assuming a collision from the front side of the vehicle body, in the initial stage of the lateral crushing type aluminum stay crushing deformation, the opposed vertical wall flanges according to the present invention do not contact each other, and the vertical wall ribs connecting these flanges are bent. Energy is absorbed by deformation.

  Next, as the crushing deformation further proceeds, as described above, the deformation load usually decreases. However, the flange formed with the energy absorbing portion having the substantially hat-shaped cross-sectional shape according to the present invention comes into contact with each other in the substantially hat-shaped cross-sectional shape portion as the crushing deformation further proceeds. Then, the contact between the flanges increases the deformation load, and it is possible to prevent the extreme decrease in the deformation load as described above.

  Moreover, this effect can be achieved without increasing the thickness of the flanges and ribs of the aluminum stay. In addition, the increase in thickness when forming the energy absorbing portion having a substantially hat-shaped cross-section on the flange is only the portion corresponding to the wall-like rib portion extending in the longitudinal direction of the vehicle body, and the increase in the weight of the component is also minimized. It is suppressed.

  Furthermore, such an energy absorbing portion having a substantially hat-shaped cross-section need not be separately formed or attached to the aluminum stay. That is, by hot extrusion of an aluminum alloy, it is possible to form an energy absorbing portion having a substantially hat-shaped cross-section as an extruded hollow shape integrally with the aluminum stay and simultaneously. Therefore, there are significant advantages such as reduction in stay production cost and improvement in production efficiency.

  Therefore, the present invention can provide a bumper device in which the aluminum stay can absorb energy at the time of collision without increasing cost and weight.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 and 2 are plan views showing an embodiment of a stay 1 according to the present invention.
1 and 2, FIG. 1 shows a right-hand side of a bumper reinforcing material (bumper R / F) 2 that extends in the center of the vehicle body parallel to the vehicle body width direction and is bent at the end. An embodiment in which the aluminum stays 1 are symmetrically attached to the wall 2b and the left inclined wall 2a is shown. On the other hand, FIG. 2 shows a partially enlarged view of the aluminum stay 1 attached to the left inclined wall portion 2a of the bumper reinforcing member 2 of FIG. The aluminum stay 1 attached to the right inclined wall portion 2b also has the same structure as this.

  1 and 2, an aluminum stay 1 is disposed between a bumper reinforcement 2 and a side member 3 of a vehicle body, and constitutes a bumper device.

  As shown in FIGS. 1 and 2, two aluminum stays 1 are spaced apart in the vehicle body width direction (longitudinal direction of the bumper reinforcing material 2) according to the shape of the left and right end portions of the bumper reinforcing material 2 in the longitudinal direction. Arranged. 1 and 2, the aluminum stay 1 constitutes a lateral crushing stay in which the vertical direction of the vehicle body is the extrusion direction.

(Basic structure of aluminum stay)
Details of the basic structure of the aluminum stay 1 will be described with reference to FIG.
The aluminum stay 1 is made of an aluminum alloy extruded hollow member whose extrusion direction is the vertical direction of the vehicle body. The basic configuration includes a pair of vertical wall-like flanges (front wall, rear wall) 5a, 5b extending in the vehicle body width direction and spaced apart from each other in the vehicle body longitudinal direction, and extending in the vehicle body longitudinal direction. It has a substantially rectangular cross-sectional shape (hollow shape) composed of vertical wall-shaped ribs (left and right side walls) 6a and 6b that connect the pair of flanges 5a and 5b.

  As the basic structure of the aluminum stay 1, the flanges 5 a and 5 b may be two each, but the vertical wall-like ribs 6 a and 6 b are not limited to two, and have a substantially rectangular cross section as shown in FIG. 4 described later. Three or more sheets may be provided in a divided form.

  Here, the flange 5a on the front surface side of the vehicle body has a flat plate shape corresponding to the shape of the end portion of the bumper reinforcing member 2 to be bonded, in connection with the rear wall of the bumper reinforcing member 2. That is, the bumper reinforcement shown in FIGS. 1 and 2 is a slant wall (rear wall) as a linear or curved curved part (bent part) bent toward the vehicle body at both ends of the linear center part. 2a and 2b. For this reason, the flange 5a on the front surface side of the vehicle body in the aluminum stay 1 also has a slanted wall shape corresponding to the end shape of the bumper reinforcing material and inclined toward the vehicle body side. Therefore, the two aluminum stays 1 of FIGS. 1 and 2 are arranged symmetrically on the inclined wall portions (rear wall) 2a and 2b of the bumper reinforcing member 2, respectively. Incidentally, if the bumper reinforcing material is linear including the end shape, the flange 5a on the front surface side of the vehicle body is also linear and is arranged in parallel with the flange 5b on the rear surface side of the vehicle body.

  Further, the flange 5b on the rear side of the vehicle body has a shape corresponding to the front side joining flange 3a of the side member 3 to be joined, that is, in the vehicle body width direction (vehicle body direction) in connection with the front side joining flange 3a of the side member 3. It has a flat plate shape extending in the width direction) and the vertical direction of the vehicle body (substantially vertical direction).

  The flanges 5a and 5b are flat plate-like (vertical wall-like) projecting flanges 4a, 4b, 4c, and 4d that project outward from the vertical wall-like ribs 6a and 6b (vehicle width direction side). Is integrated. In these overhanging flanges, the flange 5a and the flange 5b are joined to the bumper reinforcing member 2 and the side member 3, respectively. In this embodiment, overhanging flanges 4a, 4b, 4c, and 4d are provided on both the vertical wall-like flanges 5a and 5b and on both sides of the flanges 5a and 5b.

  If there is no difficulty in joining the bumper reinforcing member and the side member to the flange 5a and the flange 5b depending on the design conditions of the bumper reinforcing member and the side member, these overhanging flanges are the vertical wall-shaped flanges 5a. 5b may be provided on only one side of the flanges 5a and 5b or on either side of the flanges 5a and 5b, if necessary. However, normally, without such an overhanging flange, it becomes difficult to join the stay 1 itself to the bumper reinforcement 2 or the side member 3. For this reason, when such an overhanging flange is not formed integrally with the stay main body in advance, it is usually necessary to separately attach an attachment portion such as an overhanging flange to the stay 1 by welding or the like. The manufacturing cost is high, and the practicality may be lost.

(Stay joining)
The flange 5a on the front side of the vehicle body of the aluminum stay 1 is joined to the inclined wall portion 2a (rear wall) of the bumper reinforcing material at the overhanging flanges 4a and 4b. The flange 5b on the rear side of the vehicle body is joined to the front side joining flange 3a of the side member 3 at the overhanging flanges 4c and 4d.

  These specific joints include the overhanging flanges 4a and 4b of the aluminum stay 1, the portions of the inclined wall portions 2a of the bumper reinforcement corresponding to the overhanging flanges 4c and 4d, and the overhanging flanges 4c and 4d of the aluminum stay 1, respectively. A through hole is provided at each of the corresponding front side flanges 3a of the side members, and a bolt 7 is mechanically joined to each through hole. In addition, you may join mechanically using a stud bolt or a nut instead of this through-hole.

  In the present invention, the flanges 5a and 5b of the aluminum stay 1 are thus flange surfaces that match the joint surfaces of the bumper reinforcement and the side member, so that these parts can be easily attached without welding. Joining is possible. As a result, the stay production cost can be reduced and the production efficiency can be improved. It should be noted that the welding around the flanges 5a, 5b and the like is allowed as an aid for the mechanical joining.

(Energy absorption part with approximately hat-shaped cross section)
In FIGS. 1 and 2, reference numeral 8 denotes an energy absorbing portion having a substantially hat-shaped cross section provided on the flange 5 b on the rear side of the vehicle body. The energy absorbing portion 8 may be provided on either the flange 5a on the front surface side of the vehicle body or the flange 5b on the rear surface side of the vehicle body, or both, but it is necessary to be formed on at least one of the flanges.

  The energy absorbing portion 8 has a substantially hat-shaped cross-sectional shape (hollow shape) protruding in the longitudinal direction of the vehicle body within the substantially rectangular cross-section. Specifically, it is composed of vertical walls 8a and 8b that rise from the flange 5b toward the front side in the longitudinal direction of the vehicle body, and a flat top 8c that faces the front side of the vehicle body as a vertical wall, and has a substantially hat-shaped cross-sectional shape. Forming. Here, although the substantially hat-shaped cross-sectional shape shows a substantially rectangular shape, the change of the cross-sectional shape is allowed as long as the energy absorption function is not deteriorated. That is, the vertical walls 8a, 8b and the top 8c may be R-shaped or connected in an arc shape, and the entire cross-sectional shape of the energy absorbing portion 8 formed by the vertical walls 8a, 8b and the top 8c is made an arc shape. Also good.

  Since the energy absorbing portion 8 has such a shape and structure, as described above, with the further progress of the crushing deformation, the flanges 5a and 5b facing each other in the substantially hat-shaped cross-sectional shape portion. Contact. Then, the contact between the flanges 5a and 5b increases the deformation load, and it is possible to prevent the extreme decrease of the deformation load as described above.

  That is, as described above, when the aluminum stay is formed of a high-strength material, as the crushing deformation progresses, the bending deformation portions of the vertical wall-like ribs 6a and 6b spread outward in the vehicle body width direction and are generated in this bending deformation portion. Since the bending moment does not increase, the deformation load P decreases. On the other hand, according to the present invention, as the crushing deformation of the stay progresses, in addition to the bending deformation of the vertical wall-like ribs 6a and 6b, the energy absorbing portion 8 is crushing and deforming to increase the deformation load P.

  As described above, this effect can be achieved without increasing the thickness of the ribs 6a and 6b of the aluminum stay. That is, it can be said that the maximum load at the start of the crushing deformation does not change and the amount of energy absorption can be increased. Further, the thickness increase when the energy absorbing portion having the substantially hat-shaped cross-sectional shape is formed on the flange is only the portion corresponding to the wall-like rib portion extending in the longitudinal direction of the vehicle body. Minimized.

(Total wall thickness of the energy absorption part)
Here, the vertical wall 8a, the wall thickness is the total of each thickness t ₃ of _{8b T 3 (T 3 = t} 3 + t 3) at the energy absorbing portion 8, the vertical wall-like rib 6a constituting the stay 1 body, It is preferable that the thickness is equal to or smaller than (less than or equal to) the thickness T ₂ (T ₂ = t ₂ + t ₂ ) obtained by adding the thicknesses t ₂ of 6b.

Vertical wall 8a of the energy absorbing portion 8, 8b total thickness T ₃ of, stay 1 vertical wall-like rib 6a constituting the main body, greater than the total thickness T ₂ of the 6b, required to crush the energy absorbing portion 8 The deformation load is equal to or greater than the crushing load of the vertical wall-like ribs 6a and 6b constituting the stay 1 body. At the start of crushing of the energy absorbing portion 8, the bending deformation of the vertical wall-like ribs 6a and 6b constituting the stay 1 main body proceeds and the deformation load is reduced, but the load required for the bending deformation is still necessary. . For this reason, the deformation load at the start of the collapse of the energy absorbing portion 8 becomes higher than the start of the collapse of the main body of the stay 1, and the maximum load may increase.

(The shape of the vertical wall in the energy absorber)
The vertical walls 8a and 8b in the energy absorbing portion 8 and the vertical wall-like ribs 6a and 6b constituting the stay 1 main body may have the flat plate shape shown in FIGS. You may do it. This curve refers to the vertical walls 8a and 8b (vertical wall-like ribs 6a and 6b) as shown in FIG. 3 spreading outward in the vehicle body width direction, or although not shown, the vertical walls 8a and 8b ( The vertical wall-like ribs 6a and 6b) are curved in such a manner as to narrow inward in the vehicle body width direction. Further, as shown in FIG. 3, the curved shape may be such that the vertical walls 8a and 8b (vertical wall-shaped ribs 6a and 6b) are curved so as to form a substantially “<” shape, or not shown. However, the vertical walls 8a and 8b (vertical wall-like ribs 6a and 6b) may be curved in an arc shape.

  As described above, when the vertical walls 8a and 8b or the vertical wall-like ribs 6a and 6b are curved in the vehicle body width direction, a curved portion such as a substantially "<"-shaped bent portion becomes a starting point of deformation. Thereby, compared with the flat shape shown in FIGS. 1 and 2, it is possible to further suppress a rapid increase in the maximum load accompanying the buckling of the energy absorbing portion 8 or the buckling at the initial stage of the collapse. When the vertical wall is curved in this way, the maximum load decreases, and if the vertical wall thickness is the same, the energy absorption amount itself decreases, but the maximum load and subsequent deformation load are small. There is an advantage of becoming. In other words, if the wall thickness is set thick and the vertical wall is curved, the weight increases, but a stay structure with better energy absorption performance can be obtained within the limited maximum load limit. I can say that. The shape and thickness of these vertical wall shapes are conveniently selected from the maximum load limit required as a design requirement, the required energy absorption amount, and the target part weight.

  Therefore, in the present invention, the vertical walls 8a and 8b and / or the vertical wall-shaped ribs 6a constituting the main body of the stay 1 according to the maximum load and energy absorption required for the stay, such as for each vehicle type, The shape of 6b may be a shape that is previously curved in the vehicle body width direction, such as the substantially "<" shape.

(Plate shape at the energy absorption part)
In addition, a flat plate-like top portion 8c facing the vehicle body front side as a vertical wall in the energy absorbing portion 8 is arranged in parallel to the collision direction from the front of the vehicle body, and forms the substantially hat-shaped cross-sectional shape. It is desirable that the flange 5b (or the flange 5a on the front side of the vehicle body) is subjected to a deformation load in the form of a surface.

  In this sense, the substantially hat-shaped cross-sectional shape of the energy absorbing portion 8 is formed on the flange 5b side on the rear side of the vehicle body, and the flat top portion 8c is parallel to the vehicle body width direction or has a recent offset barrier collision. Is about 10 DEG. It is desirable to set the following angle.

  The hat-shaped cross-sectional shape of the energy absorbing portion 8 may be formed in the flange 5a on the front side of the vehicle body. However, the flange 5a on the collision surface side with respect to the collision direction from the front of the vehicle body is likely to be rotationally deformed due to the collision. . For this reason, when it is formed on the flange 5a on the front side of the vehicle body, if the angle of the collision surface of the flat plate-like top portion 8c is not controlled well, the above-described effect of preventing an extreme decrease in the desired deformation load can be obtained. Becomes difficult. For this reason, it is desirable to form the energy absorbing portion 8 on the flange 5b side on the rear side of the vehicle body as described above.

  2, the stay 1 has two wall-like ribs 6 and one energy absorbing portion 8 formed inside the stay. As shown in FIG. 4, three or more wall-like ribs 6 are provided, The substantially rectangular cross section may be divided into two or more, and each of the energy absorbing portions 8 and 8 may be installed in each of the substantially rectangular cross sections. Further, the energy absorbing portion 8 may be provided only in any one of the substantially rectangular cross sections, and the energy absorbing portion 8 may not be provided in the other substantially rectangular cross section.

  The size, shape, and installation method of these energy absorbing portions 8 are determined depending on the vehicle type and the like, and the flanges 5a and 5b that are opposed to each other as the crushing deformation progresses due to the target deformation load and the constraints such as the material and shape. The load is selected so that the deformation load due to the contact increases.

(Manufacture of aluminum stays)
As described above, the aluminum stay 1 constitutes a lateral crushing stay in which the vertical direction of the vehicle body is the extrusion direction. Therefore, the aluminum stay 1 can be manufactured by cutting an aluminum alloy extruded profile in the plane direction with the vertical direction of the vehicle body as the longitudinal direction and the plane direction of FIGS. Further, as described above, the flange 5a on the front surface side of the vehicle body is configured as a slanted wall shape inclined to the vehicle body side corresponding to the end shape of the bumper reinforcement, and as described above, the aluminum stays 1 are symmetrical to each other. In this case, the left and right aluminum stays 1 can be simultaneously manufactured with the same extrusion die.

  Therefore, the energy absorbing portion 8 and the overhanging flanges 4a, 4b, 4c, and 4d are not required to be separately formed or attached to the aluminum stay 1. That is, by hot extrusion of an aluminum alloy, it is possible to form a substantially hat-shaped energy absorbing portion 8 and overhanging flanges 4a, 4b, 4c, and 4d as an extruded hollow shape integrally with an aluminum stay and simultaneously. is there. Therefore, there are significant advantages such as reduction in stay production cost and improvement in production efficiency.

  Furthermore, by making the aluminum stay an extruded hollow shape (formed by extrusion molding), it is possible to secure the necessary thickness only on the mounting bolt surface where breakage suppression is a problem, and to reduce the thickness of the other parts It is also possible to make the aluminum stay lighter.

(Shape of each part of stay)
For the vertical wall-like ribs 6a and 6b constituting the aluminum stay 1, no particular thickness is specified. However, for the flanges 5a and 5b, as described above, it is necessary to secure a necessary wall thickness on the mounting bolt surface in order to prevent the bolt portion 7 from being broken at the joint portion between the side member and the bumper reinforcing member at the time of the vehicle body collision. There is. For this reason, it is desirable that the flanges 5a and 5b have a relatively thick thickness of 2 mm or more.

  The shape, such as the height, width, and thickness of the aluminum stay 1 is not limited to the model of the automobile, the required impact load absorption capacity, and the aluminum alloy in order to demonstrate the original functions of the stay and to ensure high energy absorption. Design each according to strength and other conditions.

(Stay material)
In order to ensure the high energy absorption amount of the aluminum stay 1 including the energy absorbing portion 8, it is preferable that the stay is made of a high-strength aluminum alloy extruded shape with a 0.2% proof stress of 170 MPa or more.

  As an aluminum alloy that satisfies such characteristics, it is a general-purpose alloy that is generally used for this type of structural member application, such as AA to JIS 6000 series, 7000 series, etc., and has a relatively high yield strength and good formability, If necessary, a tempered aluminum alloy is selected and used.

  With respect to the examples in which the aluminum stays shown in FIGS. 5A to 5F are analytically modeled, the crushing characteristics were obtained by FEM analysis, and the effects of the present invention were verified. Each of these examples was a mouth-type stay with a protruding flange of the same size. Table 1 shows the shape requirements of the aluminum stays shown in FIGS.

5 (a) to 5 (c) show conventional examples A to B and C without the energy absorbing portion of the present invention, in which only the thickness of the vertical wall-like ribs 6a and 6b is changed.
5D to 5F show Invention Examples D, E, and F having the same shape as that shown in FIGS.
Invention Example D is vertical wall 8a of the energy absorbing portion 8, the total thickness T ₃ of 8b, as the preferred embodiment, vertical wall-like rib 6a constituting the stay 1 body, as compared to the total thickness T ₂ of the 6b I made it smaller.
In Invention Example E, the total thickness T ₃ of the vertical walls 8a and 8b in the energy absorbing portion 8 is the same as the total thickness T _{2 of} the vertical wall-shaped ribs 6a and 6b constituting the stay 1 body.
In Invention Example F, the total thickness T ₃ of the vertical walls 8a and 8b in the energy absorbing portion 8 is made larger than the total thickness T _{2 of} the vertical wall-shaped ribs 6a and 6b constituting the stay 1 body.

In the analysis, the crushing characteristics of only the stay main body were compared, and the crushing analysis was performed by crushing the stay with a flat plate-like rigid body simulating both the side member and the bumper reinforcement after crushing. For the crush analysis, general-purpose dynamic explicit method software LS-DYNA is used, and the material of the aluminum stay 1 is a 7000 series aluminum alloy extruded hollow material having a proof stress σ _0.2 of 310 MPa.

  Table 1 shows the results of the crushing characteristic analysis, FIG. 6 shows the deformation load-displacement relationship in the crushing characteristic analysis, and FIG. 7 shows two cross-sectional deformation forms of the conventional example A and the invention example D. .

  From these crush characteristics analysis results, it can be seen that the stays of Invention Examples D and E can increase the amount of energy absorption without increasing the maximum load as compared to the stay of Conventional Example A. On the other hand, in the stays of Comparative Examples B and C, as shown in the deformation load-displacement relationship in FIG. 6, the maximum load at the initial stage of crushing is high, and the tendency for a sudden drop in load after the maximum load does not change. It can be seen that the energy absorption performance is not so good.

  As shown in the deformation load-displacement relationship in FIG. 6, the stay of the present invention shows the same deformation load-back surface displacement relationship as that of the conventional aluminum stay until the maximum load and immediately thereafter. However, after the maximum load (with the progress of the crushing deformation), the opposing flanges 5a and 5b come into contact with each other in the substantially hat-shaped cross-sectional shape portion of the energy absorbing portion 8 as shown in FIG. And it turns out that the further fall of the deformation load is prevented by contact between these flanges 5a and 5b.

  Further, as the crushing deformation further proceeds, as shown in FIG. 7, a “<” shape deformation is generated along with the stay main body, in which the substantially hat-shaped cross-sectional shape portion of the energy absorbing portion 8 spreads outward. It can be seen that this deformation increases the deformation load in the later stage of deformation, thereby increasing the amount of energy absorbed in the later stage of crushing. Further, when the vertical wall-shaped ribs 6a and 6b constituting the stay 1 and the vertical walls 8a and 8b of the energy absorbing portion 8 are deformed from a straight shape to a "<" shape, a sudden increase in load occurs. I understand that. For this reason, it is clear that when these vertical walls are set in a “<” shape in advance, this rapid increase in the maximum load can be suppressed. In other words, as described above, if the vertical wall is shaped like a dogleg and the thickness of the vertical wall portion is increased, it is possible to obtain a stay structure with higher energy absorption efficiency, although the weight increases. .

Further, in the comparison between the inventive examples, it can be seen that although the energy absorption amount of the inventive example F is increased, the maximum load is slightly increased as compared with the stay of the conventional example A. On the other hand, it can be seen that Invention Examples D and E increase the amount of energy absorption without increasing the maximum load as compared with Invention Example F. Therefore, it can be seen that it is effective to reduce the total thickness T ₃ of the energy absorbing portion vertical walls 8 a and 8 b compared to the total thickness T ₂ of the ribs 6 a and 6 b constituting the stay 1 body.

  From the above results, the significance of the requirements and preferred requirements of the stay of the present invention for the energy absorption improvement effect at the time of each collision is supported.

  As described above, the present invention can provide a bumper stay and a bumper device in which an aluminum stay can absorb energy at the time of collision without increasing cost and weight. Therefore, it is suitable for a bumper device that has a light weight requirement and an energy absorption requirement at the time of collision with respect to the bumper stay.

1 is a plan view showing an embodiment of a bumper stay or bumper device of the present invention. 1 is a plan view showing an embodiment of a bumper stay or bumper device of the present invention. It is a top view which shows the other embodiment of the bumper stay thru | or bumper apparatus of this invention. It is a top view which shows the other embodiment of the bumper stay thru | or bumper apparatus of this invention. It is a top view which shows the analysis model in an Example. It is explanatory drawing which shows the deformation load-back surface displacement relationship in an Example. It is explanatory drawing which shows the deformation | transformation form of the cross section in an Example.

Explanation of symbols

1: Stay, 2: Bumper reinforcement, 3: Side member, 4: Overhang flange 5: Flange, 6: Rib, 7: Bolt, 8: Energy absorption part,

Claims (7)

  A bumper stay disposed between a bumper reinforcement member and a side member of an automobile body, and the bumper stay is made of an aluminum alloy extruded hollow shape having an extrusion direction in the vertical direction of the vehicle body, and extends in the vehicle body width direction. While having a substantially rectangular cross-sectional shape composed of a pair of vertical wall-like flanges arranged at intervals in the longitudinal direction and vertical wall-like ribs extending in the longitudinal direction of the vehicle body and connecting the pair of flanges, Either or both of the vertical wall-shaped flanges have a projecting flange projecting in the vehicle width direction side with respect to the vertical wall-shaped rib. In this projecting flange, either the bumper reinforcing material or the side member / Alternatively, both of them are joined, and at least one of the flanges has a substantially hat-shaped cross-sectional shape that projects in the longitudinal direction of the vehicle body within the substantially rectangular cross section. Banpasutei, characterized in that There are formed.   2. The bumper stay according to claim 1, wherein an energy absorbing portion having a substantially hat-shaped cross-sectional shape is formed on the rear face side flange of the vehicle body.   The total thickness of the vertical wall portion in the longitudinal direction of the vehicle body constituting the energy absorbing portion having the substantially hat-shaped cross-sectional shape is smaller than the total thickness of the vertical wall-shaped ribs constituting the stay. No bumper stay.   A longitudinal wall portion in the longitudinal direction of the vehicle body that constitutes the energy absorbing portion of the substantially hat-shaped cross section and / or a longitudinal wall-shaped rib that extends in the longitudinal direction of the vehicle body and connects the pair of flanges in the vehicle body width direction. The bumper stay according to any one of claims 1 to 3, which is curved toward the front.   5. The bumper stay according to claim 1, wherein the front-side flange of the vehicle body has an inclined or curved shape corresponding to the inclined or curved shape of the rear surface side of the bumper reinforcing material.   The bumper stay according to any one of claims 1 to 5, wherein the aluminum alloy extruded hollow member is made of a 6000 series or 7000 series aluminum alloy having a 0.2% proof stress of 190 MPa or more. The bumper apparatus which has arrange | positioned the bumper stay in any one of Claims 1 thru | or 6 between the bumper reinforcement material and side member of a motor vehicle body.

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