JP2003053462A - Bumper reinforcement for vehicle body and press forming method and device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize deep bending above 10 degrees without causing wrinkles with respect to bumper reinforcement. SOLUTION: A bumper reinforcement 14 is installed through bumper stays at the front end of a vehicle body side member 12. The bumper reinforcement 14 has a bend at both ends 14-2 relative to the center part 14-1. On the side face (rear face) of the bumper reinforcement 14 where compression is applied by bending, there is formed a long narrow recess 18 having a partially circular cross sectional shape extending in a long narrow fashion longitudinally. In the recess 18, an excess thickness flows in that is produced on the compressed side in bending from a rectangular tube stock, obtaining an angle in excess of 10 degrees without causing wrinkles (buckles).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bumper reinforcement, a press-bending method and a press-bending apparatus, which are made of a metal pipe material having a rectangular cross section and are installed in the vehicle body width direction.

[0002]

2. Description of the Related Art In a vehicle such as an automobile, a bumper fascia made of plastic at an end portion (front portion or rear portion) is attached to a bumper reinforcement. The bumper reinforcement is formed of a metal pipe material such as a steel pipe having a rectangular cross section, and is arranged between bumper stays extending forward from a pair of side members as vehicle body frame members. The impact applied to the bumper fascia at the time of a collision is transmitted to the side member through the bumper reinforcement and bump paste, but the slight impact is absorbed by the bumper reinforcement and bump paste, and the side member as the vehicle body skeleton is absorbed. It is designed to avoid permanent deformation of. That is, in a minor collision, only the replacement of bumper reinforcements and bumpers stays, and the side members are not affected by the collision.

The bumper reinforcement is arranged inside the bumper fascia. When the bumper fascia is bent at both ends in the vehicle width direction due to the design, the bumper fascia is also bent at both ends in accordance with this. It is designed to take The bending angle depends on the design of the bumper facia, but it often exceeds 10 degrees.

The simplest conventional method for bending the bumper fascia at its two ends is with a press bending device. In the conventional press bending device, a blank rectangular section steel pipe is placed so as to straddle a lower die conforming to the bumper reinforcement bending shape, and an upper die having a sharp wedge-shaped tip is sandwiched between the rectangular sectional steel pipes. It is placed above the lower mold and the tip of the wedge section of the upper mold is brought into contact with the upper side surface of the rectangular section steel pipe by moving the upper mold toward the lower mold, and the rectangular section steel pipe is bent around this contact part. I am letting you.

An alternative means of bending with a press bending device is with a pipe bender. In a pipe bender, a steel pipe having a rectangular cross section is held between a plurality of rolls to bend the pipe.

[0006]

In the case of bending with a press die, the material is compressed on the side that hits the press die,
There is excess meat on the side surface on the compression side. The amount of this surplus at the portion that is compressed by bending naturally increases as the bending angle increases. The surplus on the compression side during bending is received in the recess formed when the press die bites, but in the conventional press die, the area for receiving the surplus is narrow, so the bending angle exceeds 10 degrees. When it gets bigger, there is no place for extra meat and it becomes wrinkled. Therefore, there is a problem that it cannot be used as a product. Bending by a pipe bender can be processed without wrinkling even if it is deeply bent at more than 10 degrees, but it has a drawback that the cost is higher than that by pressing.

The present invention has been made in view of the above problems of the prior art, and it is an object of the present invention to make it possible to perform deep bending exceeding 10 degrees by pressing without causing wrinkles.

[0008]

According to the invention as set forth in claim 1, a bumper rain which is made of a metal pipe material having a rectangular cross section and is installed in the vehicle body width direction at the end portion (front portion or rear portion) of the vehicle body. In the force, the bumper reinforcement has a bent portion, and a concave portion elongated in the longitudinal direction of the bumper reinforcement is formed in a portion of the side surface of the bumper reinforcement which is compressed by bending and which is separated from the upper and lower ridges. A bumper reinforcement for the body is provided.

Explaining the function and effect of the invention of claim 1, the side surface on the compression side is left over when the bumper reinforcement is bent, but in this invention, the side surface (rear surface) on the side receiving the compression of the bumper reinforcement is. Since it has a long and narrow recess in the longitudinal direction, even if the metal pipe material is bent at an angle of more than 10 degrees, the excess meat on the compressed side is completely poured into the recess. It is possible to obtain a clean ridgeline shape above and below the bumper reinforcement without causing wrinkles.

According to the invention of claim 2, claim 1
In the invention described in (3), there is provided a bumper reinforcement for a vehicle body, wherein a> L1 when the length of the recess is a and the vertical height of the bumper reinforcement is L1.

Explaining the function and effect of the invention of claim 2, wrinkles at the time of bending are caused by the excess thickness of the compression receiving side overlapping in the height direction. By making the length a of the recesses larger than the vertical height L1 of the bumper reinforcement, the surplus on the side that receives compression during bending can be poured into the recesses evenly, and even in deep bending exceeding 10 degrees, wrinkles The occurrence can be completely suppressed.

According to the invention of claim 3, claim 1
In the invention described in (1), there is provided a bumper reinforcement for a vehicle body, wherein the recess has a shape that becomes deeper toward a center thereof in a longitudinal direction.

Since the concave portion is deepened toward the center, the meat is smoothly flowed on the compressed side, and a large bending angle can be obtained without wrinkles.

According to the invention of claim 4, claim 3
In the invention described in (3), when the maximum depth of the recess is d and the width of the bumper reinforcement in the front-rear direction is L2, d> (1
/ 3) x L2 is provided, which is a bumper reinforcement for a vehicle body.

When the maximum depth of the recess is d and the width of the bumper reinforcement in the front-rear direction is L2, d> (1/3) × L2
It was possible to realize a large bending angle by using, and this could be confirmed by the results of model experiments by the finite element method.

According to the invention described in claim 5, in a method of bending a metal pipe material having a rectangular cross section to form a bumper reinforcement, the metal pipe material is supported at both ends thereof, and is opposed to the metal pipe material to form a metal pipe material. A pressure protrusion having an elongated cross-sectional shape is disposed in the longitudinal direction of the metal plate, and the pressure protrusion and the metal pipe material are relatively moved in the approaching direction so that the tip of the pressure protrusion bites into the opposing surface of the metal pipe material to form a concave portion. By bending the metal pipe material around the biting part of the pressure protrusion to the metal pipe material, and flowing the excess thickness generated on the side surface of the metal pipe material that is compressed during bending to the recesses, the bumper reinforcement with a large bending angle can be formed. Provided is a press bend forming method for performing bend forming without wrinkles.

Explaining the operation and effect of the invention of claim 5, the tip of the pressure projection forms a recessed recess on the opposing surface of the metal pipe at the time of bending forming from the metal pipe to the bumper reinforcement, and at the same time the center of this recess is formed. Then, the bending of the rectangular pipe material progresses, and finally the bending angle according to the molding surface of the lower mold is obtained. Since the pressure protrusion has a cross-sectional shape elongated in the longitudinal direction of the metal pipe material, the recess formed by the pressure protrusion biting into the opposing side surface of the metal pipe material also extends in the longitudinal direction of the metal pipe material. Since the extra thickness generated on the side of the metal pipe that receives compression is made to flow in the recesses, it is possible to perform bending without wrinkles (buckling) despite the large bending angle, for example, 10 to 20 degrees. Can be realized.

According to the invention of claim 6, claim 5
In the invention described in paragraph 1, when the length in the cross section of the pressure projection is a ′ and the vertical height of the metal pipe material is L1, a ′>
A press bending method is provided, which is L1.

Explaining the operation and effect of the invention of claim 6, the amount of surplus to be poured into the recess so as not to cause wrinkles at the time of bending at a bending angle of 10 degrees or more is the height L1 of the pipe material and 1/3 This corresponds to the amount of meat when a concave shape is formed at a depth of × L2 minutes, but in the present invention, the length a ′ of the pressure projection in the cross section is equal to or greater than the height L1 of the pipe material. Therefore, it is possible to pour excess meat generated when the pipe material is bent into the recess.

According to the invention of claim 7, claim 5
In the invention described in (1), there is provided a press bending forming method, wherein the pressing protrusion has a shape in which a central portion in the longitudinal direction of the bumper reinforcement is largely projected toward the metal pipe material.

The operation and effect of the invention of claim 7 will be described. The structure in which the pressure projection protrudes toward the tube material toward the center of the pressure projection makes the flow of the meat toward the concave portion during bending good, and makes a large bending angle. Can be obtained.

According to the invention described in claim 8, the central portion has a molding surface corresponding to a bent shape of the bumper reinforcement bent straight at both ends, and a metal pipe material having a rectangular cross section is placed on both ends thereof. And a lower die for pressing the bent portion of the lower die, and an upper die having a metal pipe material sandwiched therebetween and arranged above the lower die, wherein the pressure protrusion is in the longitudinal direction of the metal pipe material. There is provided a press bending apparatus characterized by having a lateral cross-sectional shape that extends toward the center and a side surface shape in which a central portion projects toward a metal pipe material.

The operation and effect of the invention of claim 8 will be described. By moving the lower die and the upper die in the joining direction,
The pressure projection of the upper die comes into contact with the upper surface of the metal pipe material, and when it partially digs into it, it becomes a recess and at the same time the bending of the metal pipe material progresses, and finally the bending angle according to the molding surface of the lower die is obtained. . Since the pressure protrusion has a cross-sectional shape that extends in the longitudinal direction of the metal pipe material, the recess formed by the biting of the pressure protrusion on the side surface of the pipe material extends elongated in the longitudinal direction of the pipe material, and during bending, Since the extra thickness generated on the compression side can be poured into the concave portion without a gap, bending processing without wrinkles (buckling) can be performed.

According to the invention of claim 9, claim 8
In the invention described in (1), there is provided a press bending apparatus characterized in that the upper die has a pair of pressure projections spaced apart in the longitudinal direction of the metal pipe material.

The operation and effect of the invention of claim 9 will be described below.
Since the upper mold has a pair of pressure projections, the bumper reinforcement bent at both ends can be efficiently obtained by one pressing operation.

According to the tenth aspect of the invention, in the invention of the eighth aspect, the length in the cross section of the pressure projection is a ', and the vertical height of the metal tube is L1.
A press bending apparatus is provided which is> L1.

Explaining the function and effect of the tenth aspect of the invention, the amount of surplus to be poured into the recess so as not to cause wrinkles at the time of bending at a bending angle of 10 degrees or more is 1/3 of the height of the pipe material and 1/3. It corresponds to the amount of meat in the case of forming a concave shape with a depth of × L2 minutes, but the length a'of the pressure projection in the cross section is equal to or greater than the height L1 of the pipe material. It is possible to pour extra meat generated when the pipe material is bent into the recess.

According to an eleventh aspect of the present invention, in the eighth aspect of the present invention, the pressure projection has a shape in which the central portion in the longitudinal direction of the bumper reinforcement is largely projected toward the metal pipe material. There is provided a press bending device characterized in that

The operation and effect of the invention of claim 11 will be described. The structure in which the pressurizing projection is protruded toward the pipe material toward the center of the pressurizing projection makes the flow of the meat toward the concave portion during bending good, and a large bending angle. Can be obtained.

[0030]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 schematically shows a front portion of a body of an automobile related to the present invention, and 10 is a side member which is a skeleton of the automobile body, and is provided on both sides of the vehicle body. As is well known, the side member 10 is made of steel.

A bump paste 1 is provided at the front end of the side member 10.
2 is fixed by fasteners (not shown) such as bolts,
Bumper reinforcement 14 between the left and right bumpers stays 12
Are also fixed by fasteners (not shown) such as bolts. The bumper reinforcement 14 has a middle portion 14-1 which is linear, but both end portions 14-2 which are bent at an angle α (see FIG. 4). The present invention is a bumper reinforcement, and both end portions are formed at an angle α of more than 10 degrees with respect to the linear intermediate portion 14-1.
Suitable for those with 14-2 bends. The bumper reinforcement 14 has a rectangular cross section (see FIGS. 2 and 3) and is formed by bending a rectangular cross section steel pipe by a press. The bumper reinforcement 14 having a rectangular cross section includes a front side surface 14A on the front side of the vehicle, a rear surface 14B on the rear side of the vehicle,
It has an upper surface 14C and a lower surface 14D.

In FIG. 1, reference numeral 16 is a bumper fascia formed of a plastic material. The bumper fascia 16 covers the bumper reinforcement 14 from the front of the vehicle. The bumper fascia 16 has a design in which both ends are curved, so that both ends 14-2 of the bumper reinforcement 14 inside thereof are formed into a linear middle portion 14-1 in accordance with the curved shape of the bumper fascia 16. It is bent at an angle α.

The rear surface 14B of the bumper reinforcement 14 at the bent portion from the straight middle portion 14-1 to both end portions 14-2.
A recess 18 is formed in (a surface on the side that receives compression when bending from a steel pipe). As shown in FIG. 2, this recess 1
Reference numeral 8 is elongated in the longitudinal direction of the bumper reinforcement 14 and has a cross-sectional shape that is deep in the center and smoothly connects to the bumper reinforcement side surface 14B on both sides (see FIG. 4). The recesses 18 are the bumper reinforcement vertical ridge lines 141, 142 on the bumper reinforcement rear surface 14B.
Is formed at least a distance c (FIG. 3) larger than the bumper reinforcement wall thickness t. 141 here
Is the rear surface 14B and the upper surface 14C of the bumper reinforcement 14.
The ridge line connecting the rear surface 14B and the bottom surface 14D is indicated by 142.

The vertical height of the bumper reinforcement 14 is set to L
1. When the front and rear width is L2, the width (height) of the recess 18
h is h <L1-2 × t. Therefore, a blank portion up to the ridge lines 141 and 142 is formed above and below the concave portion 18. The depth d of the recess is preferably d> L2 × 1/3. The value of the length a of the recess is larger than the value of the height L1 of the rectangular pipe material. The horizontal cross-sectional shape of the recess 18 is a partial circle, and the radius R thereof is preferably R> L1 × 1/2, and a recess having such a radius allows smooth flow of the surplus during bending. Is obtained, and a large bend angle is obtained.

FIG. 5 schematically shows a press bending apparatus for forming the bumper reinforcement 14 from a rectangular steel pipe by bending, and the press bending apparatus comprises a lower die 20 and an upper die 22.

The lower die 20 has a molding surface 20-1 which is straight at the center and bent at both ends according to the bent shape of the bumper reinforcement.
A metal pipe material M having a rectangular cross section is placed on both ends of the lower mold 20 across the molding surface 20-1. The upper die 22 includes a pair of spaced apart pressure protrusions 24. The pressure protrusion 24 is shown in FIG.
As shown in, the metal pipe material M has a rectangular cross-sectional shape extending in the longitudinal direction. That is, in the cross section of FIG. 6, the value of the length a ′ of the pressure projection 24 is considerably larger than the value of the width h ′. This length a '
Is the length a of the concave portion 18 formed on the compression-side side surface of the rectangular pipe material when the rectangular pipe material is bent by the pressure projection 24.
Corresponding to (FIG. 4), the width h ′ corresponds to the height h (FIG. 2) of the recess 18.

The lower end 24-1 of the pressure projection 24 has a rounded shape toward the metal pipe M, as shown in FIG.
In other words, the lower end 24-1 of the pressurizing projection 24 has a side surface shape in which the central portion projects toward the metal pipe material. Pressure protrusion 24
The radius of curvature R ′ of the lower end 24-1 of the
The lower end 24-1 of No. 4 corresponds to the inner diameter R of the recess 18 having the partial circular cross section formed by cutting into the pipe material M.

For bending the bumper reinforcement,
The metal pipe material M having a rectangular cross section is placed on both ends of the lower mold 20, as shown in FIG. Then, hydraulic pressure is supplied to a hydraulic cylinder (not shown) that drives the upper die 22, and the upper die 22 is driven toward the lower die 20. By the lowering of the upper mold 22, the pressurizing projection 24 is engaged with the upper surface of the metal pipe material M, and its lower end 24-1.
Is bitten into the upper surface of the metal pipe material M, and at the same time, the metal pipe material M is bent around the biting portion (recess) of the lower end 24-1 of the pressure projection 24. At this time, the material is compressed on the upper surface in contact with the lower end 24-1 of the pressure projection 24 in the bent portion of the metal pipe M, and the material is expanded on the lower face facing the lower die 20, whereby the metal pipe M is bent. proceed. Lower end of pressure protrusion 24
The material produced by the compression tends to overlap with the upper surface in contact with 24-1 and tends to overlap, but the lower end 24-1 of the pressurizing projection 24 bites into the upper surface of the metal pipe material M to form the concave portion N. To go,
The excess thickness flows into the recess N. As a result of such a material flowing into the concave portion N on the upper surface of the compression side, the material does not overlap on the compression side and wrinkles are not generated. Since the pressurizing projection 24 has an elongated cross-sectional shape (FIG. 6) that extends in the longitudinal direction of the metal pipe material M, there is sufficient room for the material that has become excessive due to compression, and The rounded shape of the lower end 24-1 of 24 ensures smooth fluidity of the material as the bending progresses.

FIG. 5B shows a state in which the upper die 22 is lowered and the pipe material M is pressed against the molding surface 20-1 of the lower die 20 to complete the processing into the bumper reinforcement. Bite N
It is needless to say that the above portion becomes the concave portion 18 in the bumper reinforcement 14.

In the present invention, the cross-sectional shape of the pressurizing projection 24 is an elongated shape extending in the longitudinal direction of the metal pipe M, and the lower end of the pressurizing projection 24 is a side surface projecting toward the metal pipe M toward the center. As a result, as the bending progresses, it is possible to promote the smooth flow of the excess thickness toward the concave portion N on the compression-side side surface of the metal pipe material M. Therefore, stable bending without wrinkles can be realized even with a bending angle α of 20 degrees.

FIG. 7 shows another embodiment of the pressure projection 24a. In this embodiment, as shown in FIG. 7B, the pressure projection 24a has a rectangular cross-sectional shape elongated in the longitudinal direction of the metal pipe material. Is similar to the first embodiment,
As a side surface shape, as shown in FIG. 7 (a), it has a mountain shape that is sharp at the center. The angle θ of this chevron is θ>
It is preferably 120 degrees. Even in such a chevron shape, during bending of a rectangular pipe material, excess meat on the compression side can be made to flow into a concave portion caused by the biting of the pressure projection 24a on the compression surface of the pipe material.
The effect is that deep bending that exceeds the limit can be performed without wrinkles.

When the bumper reinforcement 14 of the present invention is used in a vehicle body as shown in FIG. 1, the recess 18 behaves as a reinforcing bead, and the strength at the time of collision can be increased.

Although the bumper reinforcement in the front part of the vehicle has been described in the above embodiment, it goes without saying that the present invention is equally applicable to the bumper reinforcement in the rear part of the vehicle.

[Brief description of drawings]

FIG. 1 is a schematic plan view of a front portion of a vehicle body including a bumper reinforcement of the present invention.

FIG. 2 is a perspective view of a bent portion of the bumper reinforcement of the present invention.

3 is a cross-sectional view of the bumper reinforcement taken along line III-III in FIG.

FIG. 4 is a partial vertical cross-sectional view of the bumper reinforcement taken along the line IV-IV in FIG.

FIG. 5 is a schematic diagram showing steps (a) and (b) of press bending of a bumper reinforcement from a rectangular pipe material according to the present invention.

6 is a cross-sectional view taken along line VI-VI in FIG. 5, and illustrates the relative positional relationship between the upper surface of the rectangular pipe material and the pressurizing projections.

7A and 7B show pressing protrusions of a press according to another embodiment, wherein (A) is a side view and (B) is a cross-sectional view (FIG. 7A).
It is a sectional view taken along the line A-A in (a).

[Explanation of symbols]

10 ... Side member 12 ... Bum Paste 14 ... Bumper Reinforcement 14-1 ... Bumper reinforcement middle part 14-2 ... Bumper reinforcement both ends 16 ... Bumper Facia 18 ... Recess 20 ... Lower mold 22 ... Upper mold 24 ... Pressure protrusion a ... recess length d ... Depth of recess h ... Height of recess L1 ... Bumper reinforcement height L2 ... Bumper reinforcement front and rear width M ... Metal tubing α ... Bending angle

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Chihiro Sakakibara             19-1 Aobacho, Fuji City, Shizuoka Prefecture Unipres Co., Ltd.             Inside the company F-term (reference) 4E063 AA06 BA01 JA04 MA18

Claims (11)

[Claims] 1. A bumper reinforcement comprising a metal pipe material having a rectangular cross section and installed in a vehicle body width direction at an end portion of a vehicle body, wherein the bumper reinforcement has a bent portion, and the bumper reinforcement side surface is compressed by bending. A bumper reinforcement for a vehicle body, characterized in that a recessed portion elongated in the longitudinal direction is formed in a portion apart from the upper and lower ridge lines. 2. The invention according to claim 1, wherein a length of the recess is a and a vertical height of the bumper reinforcement is L1.
A bumper reinforcement for a vehicle body, wherein a> L1. 3. The bumper reinforcement for a vehicle body according to claim 1, wherein the recess has a shape deeper toward a center thereof in a longitudinal direction. 4. The invention according to claim 3, wherein when the maximum depth of the recess is d and the width of the bumper reinforcement in the front-rear direction is L2, d> (1/3) × L2. Bumper reinforcement for vehicle body characterized by 5. A method for bending a metal pipe material having a rectangular cross section to form a bumper reinforcement, the metal pipe material being supported at both ends thereof, facing the metal pipe material, and having a cross-sectional shape elongated in the longitudinal direction of the metal pipe material. A pressure protrusion is arranged, and the pressure protrusion and the metal pipe material are relatively moved in the approaching direction so that the tip of the pressure protrusion is bitten into the opposing surface of the metal pipe member to form a recess, and at the same time the pressure protrusion bites into the metal pipe member. Bending of the bumper reinforcement with a large bending angle is performed without wrinkles by bending the metal pipe material around the center and flowing the surplus generated on the side surface of the metal pipe material that is compressed during bending to the recess A press bending method characterized by the above. 6. The invention according to claim 5, wherein a ′> L1 when the length of the pressure projection in the cross section is a ′ and the vertical height of the metal pipe material is L1. Press bending method. 7. The press bend forming according to claim 5, wherein the pressurizing projection has a shape in which the central portion in the longitudinal direction of the bumper reinforcement is largely projected toward the metal pipe material. Method. 8. A lower mold for mounting a metal pipe material having a rectangular cross section on both ends thereof, which has a molding surface corresponding to a bent shape of a bumper reinforcement bent straight at both ends in a central portion,
The upper die has a pressure protrusion extending toward the bent portion of the lower die, and the upper die is disposed above the lower die with the metal pipe material interposed therebetween. The pressure protrusion has a cross-sectional shape extending in the longitudinal direction of the metal pipe material. The press bending apparatus is characterized in that the center portion has a side surface shape protruding toward the metal pipe material. 9. The press bending apparatus according to claim 8, wherein the upper mold has a pair of pressure projections spaced apart in the longitudinal direction of the metal pipe material. 10. The invention according to claim 8, wherein a ′> L1 when the length in the cross section of the pressure projection is a ′ and the vertical height of the metal tube is L1. Press bending device. 11. The press bending apparatus according to claim 8, wherein the pressurizing projection has a shape in which the central portion in the longitudinal direction of the bumper reinforcement is largely projected toward the metal pipe material. .