JP7478080B2 - Crash box and method for manufacturing crash box - Google Patents

Description

The present invention relates to a crash box that absorbs the impact when a vehicle crashes, and a method for manufacturing the same.

For example, as shown in FIG. 6, a crash box 100 that absorbs shock by collapsing when the vehicle collides is provided at the front of a body frame 121 used in a pickup truck or SUV vehicle 120. A similar crash box is also shown in Patent Document 1 listed below.

As shown in FIG. 6, a conventional crash box 100 is generally composed of a first member 101 and a second member 102. The first member 101 and the second member 102 are formed in a substantially U-shape with webs 101a, 102a extending in the longitudinal direction of the vehicle body, upper flanges 101b, 102b extending in the vehicle width direction from the upper ends of the webs 101a, 102a, and lower flanges 101c, 102c extending in the vehicle width direction from the lower ends of the webs 101a, 102a. The first member 101 and the second member 102 are then faced to each other, and the upper flanges 101b and 102b are welded together, and the lower flanges 101c and 102c are welded together, forming a crash box 100 with a closed cross-section structure.

In addition, the crash box 100 is generally provided with bead portions 101d, 102d extending in the vertical direction relative to the first member 101 and the second member 102 as shown in the figure, in order to ensure stable axial crushing and shock absorption during a collision.

In addition, the member (first member 101 in this embodiment) in which the overlapping portion of upper flange 101b and upper flange 102b (the overlapping portion of lower flange 101c and lower flange 102c) is located on the outside when assembled face to face is provided with a lance portion 101e that determines the widthwise positioning when assembled. As shown in FIG. 6, the lance portion 101e is a protruding portion formed by locally recessing upper flange 101b and lower flange 101c, and when second member 102 is moved in the vehicle width direction relative to first member 101, the longitudinal end of upper flange 102b and the longitudinal end of lower flange 102c come into contact with lance portion 101e, thereby uniquely determining the widthwise positioning.

JP 2009-61845 A

In forming such a first member 101 and a second member 102, as shown in FIG. 7, a blanking process is first performed on a plate-shaped material to form a blank pierce B10 having a predetermined shape and holes (see FIG. 7(a)), and then a forming process is performed to bend the blank pierce B10 (see FIG. 7(b)). As shown in FIG. 6, the first member 101 and the second member 102 have bead portions 101d and 102d, so it is difficult to stably make the angles of the upper flanges 101b and 102b and the lower flanges 101c and 102c relative to the webs 101a and 102a right angles in one process. For this reason, after forming, a secondary process (restriking process) is required to correct the angles (see FIG. 7(c)). Furthermore, in the first member 101, a process of performing lance processing is also required to form the lance portion 101e (see FIG. 7(d)).

As such, the conventional crash box 100 requires a process to correct the angle due to the bead portions 101d and 102d and a process to provide the lance portion 101e, which leads to increased processing costs and mold costs.

The present invention aims to solve these problems and provide a crash box that can reduce costs compared to conventional methods while still ensuring adequate shock absorption capacity, and a manufacturing method for the same.

The present invention relates to a crash box including a first member and a second member that are formed into a substantially U-shaped shape by a web extending in the longitudinal direction of a vehicle body, an upper flange extending in the vehicle width direction from an upper end of the web, and a lower flange extending in the vehicle width direction from a lower end of the web, and the first member and the second member are faced to each other, and the upper flanges and the lower flanges are welded to each other, the upper flanges and the lower flanges of the first member and the second member being welded to each other with the first member and the second member facing each other, the upper flanges and the lower flanges of the first member and the second member being spaced apart in the longitudinal direction of the vehicle body and having a plurality of cutout portions that become holes when the first member and the second member are faced to each other, and cylindrical positioning pins that position the first member and the second member via the cutout portions can be placed in the holes, the front hole portion of the upper flange and the lower flange, and the rear hole portion of the upper flange and the lower flange rearward of the front hole portion, the front hole portion of the upper flange and the front hole portion of the lower flange are provided at the same position in the fore-and-aft direction of the vehicle body, the rear hole portion of the upper flange and the rear hole portion of the lower flange are provided at the same position in the fore-and-aft direction of the vehicle body, the front hole portion is a circle or a regular polygon that can be positioned in the fore-and-aft direction of the vehicle body and in the vehicle width direction by the positioning pin, and the rear hole portion is an elongated shape that is long in the fore-and-aft direction of the vehicle body relative to the positioning pin, has a pair of straight portions extending in the fore-and-aft direction of the vehicle body, and can be positioned in the vehicle width direction by the positioning pin .

It is also preferable that at least one of the web of the first member and the web of the second member has through holes.

It is also preferable that the through hole is provided at a position corresponding to the hole portion in the fore-aft direction of the vehicle body.

The present invention also provides a method for manufacturing a crash box that includes a first member and a second member that are formed into a substantially U-shaped shape by a web extending in the longitudinal direction of the vehicle body, an upper flange extending in the vehicle width direction from the upper end of the web, and a lower flange extending in the vehicle width direction from the lower end of the web, and that is welded together with the first member and the second member facing each other, the method including the steps of: providing a plurality of cutouts that are spaced apart in the longitudinal direction of the vehicle body at the portions of the first member and the second member that will become the upper flange and the lower flange, respectively, and that will become holes when the first member and the second member are faced each other; facing the first member and the second member and placing positioning pins in the holes; welding the upper flanges together and the lower flanges together with the positioning pins placed in the holes; and removing the positioning pins from the holes after welding the upper flanges together and the lower flanges together.

In such a method for manufacturing a crash box, it is preferable that one of the holes formed by the multiple cutouts is a regular polygon or a circle, and the others are elongated shapes whose length in the fore-and-aft direction of the vehicle body is longer than their width direction.

It is also preferable to include a step of immersing the crash box in a predetermined solvent after removing the positioning pin from the hole, and then lifting it out, while discharging the solvent and/or air from within the crash box through the hole.

When a vehicle collides, the crash box of the present invention can achieve the intended impact absorbing capacity by axially crushing the vehicle starting from the hole formed by the notch in the first and second members. In addition, the bead portion as in the past is not required, and when manufacturing the crash box, the hole can be used to position the first and second members, making the lance portion unnecessary. This eliminates the machining and mold costs required to provide these, allowing for cost reduction.

1 is a perspective view showing an embodiment of a crash box according to the present invention; FIG. 2 is an exploded perspective view of the crash box shown in FIG. 1 . 4A to 4C are diagrams illustrating the process of manufacturing the first and second members that constitute the crash box. 11A to 11C are diagrams illustrating a process for manufacturing a crash box from a first member and a second member. FIG. 2 is a diagram showing a modified example of the crash box shown in FIG. 1 . FIG. 1 is a diagram showing a conventional crash box. 1A to 1C are diagrams illustrating a process for manufacturing a first member constituting a conventional crash box.

Below, we will explain an example of a crash box according to the present invention with reference to the attached drawings.

Figure 1 shows an embodiment of a crash box according to the present invention. As shown in Figures 1 and 2, the crash box 10 of this embodiment is composed of a first member 1 and a second member 2. The first member 1 is formed in a substantially U-shape with a web 1a extending in the longitudinal direction of the vehicle body, an upper flange 1b extending in the vehicle width direction from the upper end of the web 1a, and a lower flange 1c extending in the vehicle width direction from the lower end of the web 1a. The second member 2 is formed in a substantially U-shape with a shape that is substantially linearly symmetrical with respect to the first member 1 with respect to the longitudinal direction of the vehicle body as a reference, and is formed in a substantially U-shape with a web 2a extending in the longitudinal direction of the vehicle body, an upper flange 2b extending in the vehicle width direction from the upper end of the web 2a, and a lower flange 2c extending in the vehicle width direction from the lower end of the web 2a.

The first member 1 also has a plurality of cutouts at the longitudinal end of the upper flange 1b (hereinafter, the front side of the vehicle body is referred to as the upper front first cutout 1d, and the rear side of the vehicle body is referred to as the upper rear first cutout 1e) spaced apart in the vehicle body longitudinal direction. The longitudinal end of the lower flange 1c also has a lower front first cutout 1f and a lower rear first cutout 1g at the same positions in the vehicle body longitudinal direction as the upper front first cutout 1d and the upper rear first cutout 1e. In this embodiment, the upper front first cutout 1d and the lower front first cutout 1f are semicircular, and the upper rear first cutout 1e and the lower rear first cutout 1g are semicircular rectangular (half-truck shape) whose length in the vehicle body longitudinal direction is longer than the vehicle width direction.

Furthermore, the first member 1 has through holes (hereinafter, the front side of the vehicle body is referred to as the front through hole 1h, and the rear side of the vehicle body is referred to as the rear through hole 1j) that penetrate the web 1a. The front through hole 1h and the rear through hole 1j are both circular and have the same diameter. The front through hole 1h is provided at a position in the vehicle front-rear direction that corresponds to the upper front first notch 1d and the lower front first notch 1f (the vehicle front-rear direction position of the center of the front through hole 1h coincides with the vehicle front-rear direction position of the center of the upper front first notch 1d and the lower front first notch 1f). The rear through-hole 1j is provided at a position in the vehicle body longitudinal direction that corresponds to the upper rear first notch 1e and the lower rear first notch 1g (the position in the vehicle body longitudinal direction of the center of the rear through-hole 1j coincides with the position of the center in the vehicle body longitudinal direction of the upper rear first notch 1e and the lower rear first notch 1g).

The second member 2 has an upper front second notch 2d, an upper rear second notch 2e, a lower front second notch 2f, a lower rear second notch 2g, a front through hole 2h, and a rear through hole 2j, which are similar in shape to the above-mentioned upper front first notch 1d, upper rear first notch 1e, lower front first notch 1f, lower rear first notch 1g, front through hole 1h, and rear through hole 1j.

Such a first member 1 and second member 2 can be formed by the procedure shown in FIG. 3. First, a blank is made on a plate-shaped material to form a blank pierce B1 having the outer shape of the first member 1 and second member 2, the above-mentioned cutouts (upper front first cutout 1d, etc., upper front second cutout 2d, etc.), and the above-mentioned through holes (front through hole 1h, etc., front through hole 2h, etc.) (see FIG. 3(a)). Next, a forming process is performed to bend both longitudinal ends of the first member 1 and second member 2 at right angles (see FIG. 3(b)). This allows the first member 1 and second member 2 to be formed into a roughly U-shape.

The conventional first member 101 and second member 102 shown in FIG. 6 basically require four steps to form, as shown in FIG. 7. In contrast, the first member 1 and second member 2 of this embodiment can basically be formed in two steps, so processing costs and mold costs can be reduced compared to the conventional method, resulting in reduced costs.

The first member 1 and second member 2 thus formed are assembled into a crash box 10 by the procedure shown in FIG. 4. First, as shown in FIG. 4(a), either the first member 1 or the second member 2 (first member 1 in the illustrated example) is placed on a flat assembly jig J1. As shown in the figure, the first member 1 is placed on the assembly jig J1 with the web 1a oriented so that it abuts against the upper surface of the assembly jig J1.

Then, as shown in FIG. 4(b), the second member 2 is placed over the first member 1 in a state where it faces the first member 1. At this time, positioning pins J2 are placed between the upper front first notch 1d and the lower front first notch 1f, and between the upper front second notch 2d and the lower front second notch 2f. Note that the positioning pin J2 in this embodiment is cylindrical with a diameter equal to that of the upper front first notch 1d, which is semicircular. Positioning pins J2 are also placed between the upper rear first notch 1e and the lower rear first notch 1g, and between the upper rear second notch 2e and the lower rear second notch 2g. By placing the positioning pins J2 in this manner, the first member 1 and the second member 2 are uniquely positioned in the vehicle body front-rear direction and the vehicle body width direction. Depending on the processing conditions and mold accuracy when forming the first member 1 and the second member 2, for example, there may be variation in the vehicle body longitudinal position of the upper rear first notch 1e relative to the upper front first notch 1d and the vehicle body longitudinal position of the upper rear second notch 2e relative to the upper front second notch 2d. However, as described above, the upper rear first notch 1e and the upper rear second notch 2e are semi-rounded rectangular shapes (semi-track shapes), so this variation can be absorbed. Then, after the second member 2 is placed over the first member 1, the second member 2 is clamped by pressing it against the first member 1.

After that, as shown in FIG. 4(c), the upper flange 1b and the upper flange 2b are welded together at the longitudinal end of the upper flange 1b by a welding torch W, and the lower flange 1c and the lower flange 2c are welded together at the longitudinal end of the lower flange 1c by a welding torch W. Then, the two positioning pins J2 are removed to form the crash box 10 shown in FIG. 1. The crash box 10 thus assembled has a circular hole (hereinafter referred to as the front hole H1) formed by the upper front first notch 1d and the upper front second notch 2d as shown in the figure. Although not shown in FIG. 1, the lower front first notch 1f and the lower front second notch 2f also form a circular front hole H1. The crash box 10 also has a rounded rectangular (track-shaped) rear hole H2 formed by the upper rear first notch 1e and the upper rear second notch 2e. Although not shown in FIG. 1, the lower rear first notch 1g and the lower rear second notch 2g also form the rounded rectangular (track-shaped) rear hole H2.

After the crash box 10 is formed in this manner, it is attached to the front of the vehicle frame 121 by welding or the like, as in the conventional crash box 100 shown in FIG. 6. Then, by immersing the crash box 10 in a predetermined solvent (paint, rust inhibitor, etc.) and pulling it up, the solvent can be applied to the periphery of the crash box 10. When the crash box 10 is immersed in a solvent, the solvent will enter the inside of the crash box 10, but if the air inside is not released and an air pocket is formed, there will be areas where the solvent cannot be applied. Also, if the solvent remains inside the crash box 10 when it is pulled up after being immersed in the solvent, a process is required to eject air or the like into the inside of the crash box 10 to expel the remaining solvent. On the other hand, the crash box 10 of this embodiment has a front hole portion H1, a rear hole portion H2, and further front through holes 1h, 2h, and rear through holes 1j, 2j, and the air and solvent inside can be exhausted from the front hole portion H1, etc., thereby preventing these problems.

The crash box 10 formed by the above process has a weaker strength at the portion where the front hole H1 and the rear hole H2 are located than at other portions. Therefore, when the vehicle collides, axial crushing occurs starting from the front hole H1 and the rear hole H2. In other words, the crushing starts from the intended portion, so that appropriate impact absorption capacity can be exhibited. In addition, in this embodiment, the rear hole H2 is a rounded rectangular shape (truck shape) with a straight portion in the front-rear direction of the vehicle body, while the front hole H1 is circular, so that the front hole H1 is weaker in strength against the force from the front-rear direction of the vehicle body than the rear hole H2. In other words, when an impact force is applied from the front when the vehicle collides, the front hole H1 located at the front can be crushed preferentially over the rear hole H2 located at the rear, so that the function of crushing from the intended portion becomes more stable. The crash box 10 also has front through holes 1h, 2h and rear through holes 1j, 2j, which locally weaken the strength of the areas of the webs 1a, 2a where these holes are provided. In particular, in this embodiment, the front through holes 1h, 2h and rear through holes 1j, 2j are provided at positions corresponding to the front hole portion H1 and the rear hole portion H2 in the vehicle body longitudinal direction, which further stabilizes the ability to crush from the intended areas.

Although one embodiment of the present invention has been described above, the present invention is not limited to the specific embodiment, and various modifications and alterations are possible within the scope of the spirit of the present invention described in the claims unless otherwise specifically limited in the above description. Furthermore, the effects of the above embodiment are merely examples of the effects resulting from the present invention, and do not mean that the effects of the present invention are limited to the above effects.

For example, the front through holes 1h, 2h and the rear through holes 1j, 2j may be provided as necessary, and only the front through holes 1h, 2h may be left, or all of them may be eliminated as shown in FIG. 5.

The shapes of the front hole H1 and the rear hole H2 can also be changed in various ways. For example, in this embodiment, the front hole H1 is circular relative to the cylindrical positioning pin J2 for positioning during manufacturing, but the same function can be obtained by making the front hole H1 a regular polygonal shape such as a square or regular hexagon. In this embodiment, the rear hole H2 is a rounded rectangular shape (truck shape) whose length in the fore-aft direction of the vehicle body is longer than in the width direction of the vehicle, but this shape is not limited to this and other elongated shapes (for example, an ellipse or rectangle whose length in the fore-aft direction of the vehicle body is longer than in the width direction of the vehicle) are also acceptable. Two or more rear holes H2 may be provided in the fore-aft direction of the vehicle body.

1: First member 1a: Web 1b: Upper flange 1c: Lower flange 1d: Upper front first notch portion (notch portion)
1e: Upper rear first notch (cutout)
1f: Lower front first notch (notch)
1g: Lower rear first notch (notch)
1h: front through hole (through hole)
1j: Rear through hole (through hole)
2: Second member 2a: Web 2b: Upper flange 2c: Lower flange 2d: Upper front second cutout portion (cutout portion)
2e: Upper rear second cutout portion (cutout portion)
2f: Lower front second notch (notch)
2g: Lower rear second notch (notch)
2h: front through hole (through hole)
2j: Rear through hole (through hole)
10: Crash box H1: Front hole portion (hole portion)
H2: Rear hole (hole)

Claims (6)

a crash box including a first member and a second member formed into a substantially U-shape by a web extending in a front-rear direction of a vehicle body, an upper flange extending in a vehicle width direction from an upper end of the web, and a lower flange extending in the vehicle width direction from a lower end of the web, the first member and the second member being faced to each other and the upper flanges being welded to each other,
the upper flange and the lower flange of the first member and the second member, respectively, are spaced apart in the front-rear direction of the vehicle body and include a plurality of cutout portions that become holes when the first member and the second member are placed opposite each other ;
a cylindrical positioning pin that positions the first member and the second member via the notch portion can be disposed in the hole portion;
the hole portion includes a front hole portion provided in the upper flange and the lower flange, and a rear hole portion provided in the upper flange and the lower flange rearward of the front hole portion,
the front hole portion of the upper flange and the front hole portion of the lower flange are provided at the same position in a vehicle front-rear direction,
the rear hole portion of the upper flange and the rear hole portion of the lower flange are provided at the same position in a vehicle front-rear direction,
the front hole portion has a circular shape or a regular polygonal shape that can be positioned in the vehicle body front-rear direction and the vehicle body width direction by the positioning pin,
The rear hole portion has an elongated shape that is long in the fore-and-aft direction of the vehicle body relative to the positioning pin, and the crash box has a pair of straight portions extending in the fore-and-aft direction of the vehicle body and can be positioned in the width direction of the vehicle body by the positioning pin . The crash box of claim 1 , wherein at least one of the webs of the first member and the webs of the second member include through holes. The crash box according to claim 2 , wherein the through hole is provided at a position corresponding to the hole portion in the front-rear direction of the vehicle body. A method for manufacturing a crash box including a first member and a second member that are formed into a substantially U-shape by a web extending in a front-rear direction of a vehicle body, an upper flange extending in a vehicle width direction from an upper end of the web, and a lower flange extending in the vehicle width direction from a lower end of the web, the first member and the second member being placed opposite each other and the upper flanges being welded together and the lower flanges being welded together,
providing a plurality of cutout portions spaced apart in the front-rear direction of the vehicle body in the portions of the first member and the second member that will become the upper flange and the lower flange, respectively, the cutout portions being holes when the first member and the second member are placed opposite each other;
placing the first member and the second member facing each other and placing a positioning pin in the hole;
welding the upper flanges together and the lower flanges together with the positioning pins disposed in the holes;
and removing the positioning pin from the hole after welding the upper flanges together and the lower flanges together. 5. The method for manufacturing a crash box according to claim 4 , wherein one of the holes formed by the plurality of cutouts is a regular polygon or a circle, and the others are elongated shapes whose length in the fore-and-aft direction of the vehicle body is longer than its width direction. A method for manufacturing a crash box as described in claim 4 or 5, which includes a step of, after removing the positioning pin from the hole portion, immersing the crash box in a predetermined solvent and then pulling it out, and discharging the solvent and / or air from within the crash box through the hole portion.

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