JP2018149975A - Bumper reinforcement - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent or restrain the occurrence of bending by preventing or restraining stress concentration from occurring in a joint line position thereof, when bumper reinforcements are formed by press-molding a tailored blank material.SOLUTION: Bumper reinforcements 14, which are arranged in a vehicle width direction, are formed in a long shape with a plurality of joint lines by press-molding a tailored blank material in which three or more blank materials are joined together. A central part 20A, which is arranged in a central part position, has the highest strength. Right and left side parts 20B and 20C, which are arranged on both sides thereof, have strength lower than the strength. The joint lines 22A and 22B are arranged in the state of being inclined with respect to a longitudinal axis line X of the long shape.SELECTED DRAWING: Figure 2

Description

  The present invention relates to bumper reinforcement. In particular, the present invention relates to bumper reinforcement as a core material of a bumper structure installed in the front or rear of an automobile.

  A bumper structure that receives a collision load at the time of a vehicle collision is provided at the front or rear of the automobile body. The bumper structure is equipped with bumper reinforcement as a core material. The bumper reinforcement is disposed in a long shape in the width direction of the automobile body, and is supported by being connected to a frame member of the automobile body by a bumper support structure at both end positions in the width direction of the automobile body. As the bumper support structure, a crash box (C / B) in which an energy absorbing action at the time of a vehicle collision is usually used.

  Since the bumper reinforcement has a long shape, a method of forming a so-called tailored blank material by press molding, which is conventionally formed by joining a plurality of blank materials by welding, is sometimes used (see Patent Document 1 below). ). As a result, the yield of the material is improved. Moreover, desired strength characteristics in the longitudinal direction of bumper reinforcement are obtained by using a plurality of high-strength steel blanks having different tensile strengths and plate thicknesses.

JP 2001-180398 A

  By the way, when forming bumper reinforcement with a tailored blank material in which a plurality of blank materials are joined, a joining line for joining adjacent blank materials is perpendicular to the longitudinal axis of the long member. It is a joining line in the direction to be.

  In the bumper reinforcement obtained by press-molding the tailored blank material of the above-described form, when a collision load is applied to the center position, the load is sequentially transmitted and received in both end directions. During the transmission, if the joining line of the blank material is a joining line orthogonal to the longitudinal axis, the cross-sectional yield strength changes suddenly at the joining line position due to the difference in strength of the adjacent blank material, Stress concentration occurs. For this reason, there is a problem that the bumper reinforcement is bent at the position.

  The present invention was devised in view of the above-described problems, and the problem to be solved by the present invention is that when a bumper reinforcement is formed by press molding a tailored blank material, stress concentration is present at the joint line position. Is to prevent or suppress the occurrence of bending and prevent or suppress the occurrence of bending.

  In order to solve the above problems, the present invention takes the following means. In the description of the present invention (including the description of the embodiment described later and the description of the background art described above), the “blank material” refers to a flat plate member formed in a predetermined shape before joining. "Tailored blank material" is a member in a state where a plurality of blank materials are joined with a tailored blank, and indicates a state before press molding.

  The bumper reinforcement according to the first aspect of the present invention is formed into a long shape having a plurality of joining lines by press-molding a tailored blank material in which three or more blank materials are joined. The bumper reinforcement disposed in the direction, the central portion of the bumper reinforcement disposed at the center of the elongated shape between the plurality of joint lines has the highest strength, The strength is gradually reduced toward the both side portions of the bumper reinforcement located on the outer side in the vehicle width direction with respect to the plurality of joint lines, and the plurality of joint lines become the longitudinal axis of the elongated shape. It is bumper reinforcement that is formed to be inclined.

  According to the first aspect of the present invention, in the bumper reinforcement formed of a so-called tailored blank material, the joining line is formed to be inclined with respect to the longitudinal axis of the long shape. As a result, a collision load is applied to the bumper reinforcement, and when the load is transmitted in the longitudinal direction, the stress acting on the inclined joining line is dispersed. That is, there is no sudden change in the cross-sectional yield strength at the joining line position as in the prior art, and no stress concentration occurs. For this reason, the bending of the bumper reinforcement at the joining line position can be prevented or suppressed.

  Next, a second invention of the present invention is the bumper reinforcement according to the bumper reinforcement of the first invention described above, wherein the thicknesses of the portions disposed adjacent to the plurality of joining lines are the same. .

  According to the second aspect of the present invention, the stress concentration generated at the position of the joint line can be reduced as compared with the case where the plate thickness is different because the thickness of the portion disposed adjacent to the plurality of joint lines is the same. This can be prevented more effectively.

  Next, the third invention of the present invention is the bumper reinforcement of the first invention or the second invention described above. The plurality of joining lines are bumper reinforcements arranged in symmetrical positions and having a C shape.

  According to the third aspect of the present invention, the collision load input to the center position can be received in a well-balanced manner by setting the joining line position to a bilaterally symmetric position.

  Further, according to the third aspect, the blank material forming the both side portions disposed on both sides on the vehicle width direction outer side from the central portion shares the blank material if one blank material is used upside down. be able to. As a result, it is possible to share a press die for cutting a flat plate material into a blank material having a predetermined shape.

  Next, a fourth invention of the present invention is the bumper reinforcement according to any one of the first to third inventions described above, wherein the bumper reinforcement is positioned at both ends in the longitudinal direction of the long shape of the bumper reinforcement. Is a bumper reinforcement formed between the crash boxes disposed at the both end positions.

  According to the said 4th invention, a collision load can be effectively received by arrange | positioning a joining line between the crash boxes arrange | positioned at the both ends of bumper reinforcement. In other words, the collision load acting on the central position of the bumper reinforcement is transmitted to the crash box position and received, but the load moment becomes smaller as it approaches the crash box position (see FIG. 9). ). Like this characteristic, the load moment can be gradually reduced by arranging the inclined joining line.

  Next, according to a fifth aspect of the present invention, in the above-described fourth aspect, one joining line is provided on each of the left and right sides from the central position of the bumper reinforcement, and each joining line extends from the central position. It is bumper reinforcement arranged up to the position of the crash box.

  According to the said 5th invention, arrangement | positioning of the inclined joining line is made into the position of a crash box from the center position of bumper reinforcement. Thereby, the characteristic which receives the collision load transmitted to the crash box demonstrated by the above-mentioned 4th invention can be reduced more gradually from a center position to the position of a crash box. That is, the most preferable characteristic can be obtained.

  Next, a sixth aspect of the present invention is the bumper reinforcement according to any one of the first to fifth aspects of the present invention, wherein the shape of the joining line is directed in the longitudinal direction of the long shape. It is a bumper reinforcement that is V-shaped.

  According to the said 6th invention, the shape of a joining line is made into the V shape toward the longitudinal direction of the elongate shape. By being V-shaped, positioning of the blank materials to be tailored blank materials is reliably performed. That is, in the case of a straight line in which the joining line is inclined, it is easy to shift in the axial direction of the longitudinal direction, but in the case of a V shape, positioning can be performed by fitting the V shape. Thereby, the adjacent blank materials can be easily arranged in a straight line.

  According to the present invention as described above, when bumper reinforcement is formed by press molding a tailored blank material, stress concentration is prevented or suppressed from occurring at the joining line position, and bending is prevented from occurring. Can be suppressed.

It is the schematic which shows the arrangement position of the bumper structure with respect to a motor vehicle body. It is the perspective view which looked at 1st Embodiment of bumper reinforcement from the diagonally forward upper part. It is a top view (III arrow view of FIG. 2) of 1st Embodiment of bumper reinforcement. It is a front view (IV arrow line view of FIG. 2) of 1st Embodiment of bumper reinforcement. It is a side view (V arrow view of FIG.2 and FIG.4) of 1st Embodiment of bumper reinforcement. FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. 4. It is a front view of 2nd Embodiment of the bumper reinforcement shown corresponding to FIG. It is a front view of 3rd Embodiment of the bumper reinforcement shown corresponding to FIG. It is a moment diagram with respect to a collision load.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, the direction display shown in embodiment is the direction seen from the compartment of the motor vehicle.

  First, FIG. 1 shows an arrangement position of a bumper structure 10 in an automobile. The bumper structure 10 is usually disposed in the vehicle width direction with respect to the vehicle body 12 at the front and rear portions of the vehicle body 12. In FIG. 1, the front of the vehicle body 12 is indicated by an arrow Fr, and the rear is indicated by an arrow Rr. The automobile compartment is formed at the position of the automobile body 12. The bumper structure 10 includes a bumper reinforcement 14, a bumper covering member 16, and a bumper support structure 18. The bumper reinforcement 14 is disposed as a core material on the strength of the bumper structure 10. The bumper covering member 16 is disposed so as to cover the front surface of the bumper reinforcement 14. The bumper covering member 16 is disposed on the outermost surface of the bumper structure 10 and has a configuration in consideration of appearance. Usually, it is made of a resin suitable for molding a design.

  The bumper support structure 18 is disposed between the frame member (not shown) of the automobile body 12 and the bumper reinforcement 14 at positions at both ends in the longitudinal direction of the bumper reinforcement 14 (width direction when viewed from the automobile body 12). Has been. The bumper support structure 18 transmits the collision load received by the bumper reinforcement 14 to the automobile body 12 and receives it. In the present embodiment, the bumper support structure 18 is formed of a component that can absorb a collision energy called a crash box (C / B).

  In the following embodiments, the bumper reinforcement 14 disposed in the front part of the automobile body 12 will be described as an example.

  Since the bumper structure 10 of the present embodiment has the above-described arrangement configuration, the collision load F acting on the center position of the bumper structure 10 due to the frontal collision of the automobile is received as follows. First, it is received by the bumper covering member 16 and supported by the bumper reinforcement 14. And the load which acted on the bumper reinforcement 14 is received by the vehicle body 12 through the crash box (C / B) as the bumper support structure 18 disposed at both ends of the bumper reinforcement 14. At this time, the crash box (C / B) absorbs the collision energy.

  Next, the structure of the bumper reinforcement 14 of this embodiment is demonstrated. For the bumper reinforcement 14 of the present embodiment, three or more blanks having a predetermined shape are used. And the tailored blank material which this blank material joined by welding is press-molded, and the bumper reinforcement 14 is formed. In the case of this embodiment, it is the structure formed by joining three blank materials. The feature of this embodiment is the arrangement of the joining lines to be joined. The arrangement method will be described below as each embodiment.

[First embodiment]
The first embodiment is shown in FIGS. FIG. 2 shows a view of the bumper reinforcement 14 as viewed from the front obliquely above, FIG. 3 is a top view thereof, FIG. 4 is a front view thereof, FIG. 5 is a side view thereof, and FIG. -A cross-sectional view taken along line VI. As shown in FIG. 6, the cross-sectional shape of the bumper reinforcement 14 of the present embodiment is a hat-shaped cross-section, and the rear is an opening 22. For this reason, it arrange | positions so that the front-plate part 24 may become a contact surface at the time of a collision.

  The bumper reinforcement 14 includes a front plate portion 24, an upper side plate portion 28, and a lower side plate portion 32 that are contact surfaces at the time of collision, as viewed in the cross-sectional shape of FIG. 6. A recess 26 is formed at the center of the front plate portion 24 in the vertical direction as viewed in FIG. 6, and the strength of the front plate portion 24 is improved. Further, a flange portion 30 is provided at the end of the upper side plate portion 28 on the opening 22 side so as to extend upward as viewed in FIG. Similarly, a flange portion 34 is provided at the end of the lower side plate portion 32 on the opening 22 side so as to extend downward as viewed in FIG.

  The bumper reinforcement 14 having a hat-shaped cross section is formed in a long shape as shown in FIGS. 2 to 4, and is arranged in the vehicle width direction of the automobile body as shown in FIG. The long bumper reinforcement 14 has a shape that gently curves backward toward both ends. Crash boxes (C / B) 18 as bumper support structures are disposed at both end positions. In FIG. 2 to FIG. 4, the positions where the crash boxes (C / B) 18 are arranged are simply indicated by triangles. The same applies to FIGS. 7 and 8 of the embodiments described later.

  In the present embodiment, the bumper reinforcement 14 includes three portions 20A, 20B, and 20C in a form in which a tailored blank material obtained by joining three blank materials is press-molded and connected in an elongated shape. The three parts are composed of a central part 20A disposed at the central part, a right part 20B disposed at the right side of the central part 20A, and a left part 20C disposed at the left side of the central part 20A. It has become. The positions where these three portions 20A, 20B, and 20C are joined by welding in the blank material are indicated by broken joining lines 22A and 22B. The joining line 22A shows the joining part of the blank material of the central part 20A and the blank material of the right part 20B, and the joining line 22B shows the joining part of the blank material of the center part 20A and the blank material of the left part 20C. ing.

  Two joining lines 22A and 22B for joining the blanks of the three portions 20A, 20B, and 20C are disposed to be inclined with respect to the longitudinal axis X of the bumper reinforcement 14. Specifically, they are arranged in a C shape when viewed in the vertical direction of FIGS. Note that the C-shaped formation positions of the two joining lines 22A and 22B are between the crash boxes (C / B) 18 disposed at both ends of the bumper reinforcement 14.

  The two joining lines 22 </ b> A and 22 </ b> B are arranged at symmetrical positions with respect to the center position C in the longitudinal direction of the bumper reinforcement 14. Therefore, the right side portion 20B and the left side portion 20C are symmetrical with respect to the center position C.

  The joining lines 22 </ b> A and 22 </ b> B illustrated as the first embodiment are linearly formed with an inclination with respect to the axis X. However, if it is inclined with respect to the axis X, it may be formed in a curved shape instead of a straight shape. Further, the entire length of the joining lines 22A and 22B does not need to be inclined, and there may be a portion that is partially formed in the same direction as the axis X or in a direction perpendicular to the axis X. Preferably, the joining part in the bottom face part of the front plate part 24 and the recessed part 26 shown in FIG. This is because the portion is likely to be bent when the collision load F is applied.

  In the present embodiment, the materials of the three portions 20A, 20B, and 20C are made of the same steel plate, and the plate thickness is also the same. However, the strength is set to be strongest at the central part 20A at the central position, and the right part 20B and the left part 20C on both sides are set to be weaker than the central part 20A. In the present embodiment, the strength of the central portion 20A is 1180 MPa, and the strength of the right portion 20B and the left portion on both sides is 980 MPa.

  FIG. 9 shows a moment load characteristic diagram generated when the bumper reinforcement 14 is supported by the crash boxes 18 at both ends when a collision load F is applied to the central position of the bumper reinforcement 14. As can be seen from this characteristic diagram, the moment load at the center position is the largest and gradually decreases toward both sides. In the present embodiment, the strengths of the three portions 20A, 20B, and 20C described above are set according to this characteristic diagram. Therefore, the strength of the central portion 20A is the strongest, and the right side portion 20B and the left side portion 20C on both sides are made weaker.

  In addition, joining of the blank materials which form joining wire 22A, 22B in this embodiment is performed by welding a steel plate. As the welding, any appropriate welding such as laser welding, plasma welding, (mash) seam welding, friction stir welding, or the like can be used.

  In addition, shaping | molding of 3 site | parts 20A, 20B, and 20C of the bumper reinforcement 14 in this embodiment is the process of cutting a flat plate material into the blank material of a predetermined shape, the process of tailoring blank materials, and the tailored blank. And pressing the material into a predetermined bumper reinforcement 14 shape. When this forming method is used, when the joining lines 22A and 22B are in the shape of a letter C and left and right symmetrical as in the present embodiment, one of the blanks forming the right side portion 20B and the left side portion 20C is turned over. By using it, a flat blank material can be shared. As a result, it is possible to share a press die for cutting a flat plate material into a blank material having a predetermined shape.

  Next, the operational effects of the first embodiment described above will be described. In the present embodiment, the joint lines 22A, 22B of the three portions 20A, 20B, 20C are disposed so as to be inclined with respect to the longitudinal axis X of the bumper reinforcement 14. Thereby, when the collision load applied to the central position of the bumper reinforcement 14 is transmitted to the position of the crash box 18, the load stress acting on the inclined joint line is dispersed. For this reason, the bending of the bumper reinforcement 14 at the joining lines 22A and 22B can be prevented or suppressed.

  In addition, since the joining lines 22A and 22B are disposed at an inclination, the strength during the inclination is increased so that the blank material corresponding part 20A in the central portion and the blank material corresponding parts 20B on both sides are disposed. It gradually decreases with an area ratio of 20C. That is, at the position close to the central portion, the area ratio of the blank material corresponding portion 20A in the central portion is larger than the area ratio of the blank material corresponding portions 20B and 20C on both sides, and the influence of the strength of the blank material corresponding portion 20A in the central portion is large. The area ratio of the blank material-corresponding portion 20A in the central portion is gradually reduced toward the both end portions, the area ratio of the blank material-corresponding portions 20B, 20C on both sides is increased, and both blank material-corresponding portions 20B, 20C are The effect of strength increases, and the strength gradually decreases. This is along the moment load characteristic diagram shown in FIG.

[Second Embodiment]
A second embodiment is shown in FIG. FIG. 7 is a view corresponding to FIG. 4 in the first embodiment described above. Note that in the second embodiment, the description of the components that are substantially the same as those of the first embodiment described above may be omitted by providing the same reference numerals.

  As shown in FIG. 7, the right side joining line 22 </ b> A and the left side joining line 22 </ b> B of the second embodiment are separated from the upper position as viewed in FIG. B) It is formed to be inclined toward the lower position as seen in FIG. In the second embodiment, the two joining lines 22A and 22B are also used. It is arranged at a symmetrical position from the center position C, and receives a collision load in a balanced manner.

  According to the second embodiment described above, the inclination forming range of the joining lines 22A and 22B of the second embodiment is the maximum range from the center position C to the crush box (C / B) 18 position. Thereby, it can be set as the load characteristic most approximated to the characteristic diagram shown in FIG. 9 demonstrated in 1st Embodiment mentioned above.

[Third Embodiment]
A third embodiment is shown in FIG. FIG. 8 is a view corresponding to FIG. 4 in the first embodiment and FIG. 7 in the second embodiment. Note that in the third embodiment, the description of the same components as in the first embodiment and the second embodiment described above may be omitted by retaining the same reference numerals.

  As shown in FIG. 8, the right side joining line 22 </ b> A and the left side joining line 22 </ b> B of the third embodiment are formed as a V shape toward the longitudinal axis X, and are inclined with respect to the axis X. Is done. Each V-shape is formed so that the lower end Y of the V-shape is directed toward both ends of the bumper reinforcement 14. The V-shaped joining lines 22A and 22B are arranged symmetrically from the center position C, and can receive a collision load in a balanced manner.

  According to 3rd Embodiment mentioned above, positioning of the blank material used as a tailored blank material is performed reliably because joining line 22A, 22B is V-shaped. That is, in the case of a straight line in which the joining line is inclined, it is easy to shift in the axial direction of the longitudinal direction, but in the case of a V shape, positioning can be performed by fitting the V shape. Thereby, the adjacent blank materials can be easily arranged in a straight line.

  While specific embodiments of the present invention have been described above, the present invention can be implemented in various other forms.

  For example, the cross-sectional shape of the bumper reinforcement of the above-described embodiment is a hat-shaped shape. However, the cross-sectional shape is not particularly specified. Moreover, it is applicable also to the bumper reinforcement of the form by which a reinforcement member is arrange | positioned suitably.

  Further, in the above-described embodiment, the bumper reinforcement is configured by the three parts of the central part 20A, the right part 20B, and the left part 20C, but is not limited to the three parts, and forms a plurality of three or more parts. A plurality of blank materials may be connected and configured.

  Further, in the above-described embodiment, the inclined joining lines are arranged symmetrically, but it is not always necessary to be symmetrical. However, from the viewpoint of receiving a collision load in a well-balanced manner, it is preferable to use a symmetrical arrangement.

DESCRIPTION OF SYMBOLS 10 Bumper structure 12 Automobile body 14 Bumper reinforcement 16 Bumper covering member 18 Bumper support structure (crash box)
20A Central part 20B Right part 20C Left part 22A Right joint line 22B Left joint line 24 Front panel part 26 Recess 28 Upper side panel part 30 Flange part 32 Lower side board part 34 Flange part

Claims (6)

It is a bumper reinforcement that is formed into a long shape having a plurality of joining lines by press molding a tailored blank material in which three or more blank materials are joined, and is arranged in the vehicle width direction,
The central part of the bumper reinforcement disposed at the central portion of the elongated shape between the plurality of joint lines has the highest strength, and is located outside in the vehicle width direction with respect to the plurality of joint lines. The strength is gradually reduced as it goes to both sides of the bumper reinforcement located,
The bumper reinforcement in which the plurality of joining lines are formed to be inclined with respect to the longitudinal axis of the elongated shape. The bumper reinforcement according to claim 1,
The bumper reinforcement in which the plate thickness of the portion disposed adjacent to the plurality of joining lines is the same. The bumper reinforcement according to claim 1 or 2,
The bumper reinforcement in which the plurality of joining lines are arranged at symmetrical positions and have a C-shape. The bumper reinforcement according to any one of claims 1 to 3, wherein
Crash boxes are arranged at both end positions in the longitudinal direction of the long shape of the bumper reinforcement,
The joint line is bumper reinforcement formed between crush boxes disposed at both end positions. The bumper reinforcement according to claim 4,
One joint line is provided on each of the left and right sides from the central position of the bumper reinforcement, and each joint line is disposed from the central position to the position of the crash box. The bumper reinforcement according to any one of claims 1 to 5,
The bumper reinforcement in which the shape of the joining line is a V shape oriented in the longitudinal direction of the long shape.

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