JP2002249067A - Strength member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an extruded shape capable of simplifying the boring work and the mounting piece molding work to be mounted to another member, and lowering a peak value of a yielding point stress (equivalent to initial buckling load) to the axial compression load. SOLUTION: A partition 3 defining plural chambers 4 is inwardly collapsed to shear a connection part of a frame 2 and the partition 3, and only an end part of the extruded shape 1 is formed into one chamber 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention facilitates drilling and beading of an extruded material having a plurality of chambers (hollows or hollows), and yield stress (initial buckling) when a compressive load is applied in the axial direction. The present invention relates to a strength member that reduces a load (equivalent to a load) and exhibits a sufficient energy absorbing ability.

[0002]

2. Description of the Related Art An extruded material having a plurality of chambers (hollows or hollows) has a partition (rib) therein, and generally,
The cross-sectional shape is a double-hollow day with two rooms and three rooms.
The character with three triple hollow eyes and the character with four rooms are often used. An aluminum alloy or steel extrusion having such a cross section connects, for example, a bumper reinforcement to a front part of a vehicle and a side member on a vehicle body side of the vehicle (equivalent to a crash box) to form a bumper reinforcement. When an impact load at the time of a collision is applied, the transmission of the impact force to the vehicle body side is minimized, and it is used as a strength member that prevents shock to occupants and damage to the vehicle body.

As described above, the strength member uses both ends as attachment portions to other members, and absorbs a compressive load acting in the longitudinal direction thereof while plastically deforming the same. In order to attach the strength member to another member, a hole is drilled at the end of the strength member. Leaves problems with fixed strength. Further, when trying to drill a large hole in the strength member, in the case of a single hollow (one chamber) extruded member, a jig is put inside and the large hole can be processed by press work. In an extruded material having a chamber (hollow or hollow), an internal partition makes it impossible to make a large hole.

When a compressive load is applied to an extruded material having a plurality of chambers in the longitudinal direction, that is, in the axial direction, as shown in a dotted line in FIG. A yield point stress A having a high peak value corresponding to a load, and a subsequent plastic region stress (a region where the applied load is absorbed and the impact force or the like is attenuated) B are shown. For this reason,
When the aforementioned extruded die is used as a crash box as one application example of a strength member, a low yield stress at which a passenger can easily withstand a high yield stress at a low value and a yield point at which vehicle body damage is minimized. In order to lower the stress and secure a high energy absorption, the average stress C in the plastic region B
It is desired to raise.

[0005] For this reason, Japanese Patent Application Laid-Open No. 5-65076 teaches that a part of a partition is cut off so as to form an inwardly inclined portion. Japanese Unexamined Patent Publication No. Hei 7-145842 discloses that a groove or a ridge is provided at an end in the longitudinal direction of a mold material, and Japanese Unexamined Patent Publication No. Hei 11-208518 discloses that a load is applied by partially cutting off an axial end face of a hollow mold material. Teach to reduce the area.

[0006] The prior art proposes processing means such as drilling and cutting to secure a low yield point stress and a high energy absorption. However, as described above, a plurality of chambers (hollows or hollows) are formed. It is not practical to apply such conventional processing means to the extruded die material, because the processing operation is complicated and difficult. In addition, there is a disadvantage that the degree of reduction of the yield point stress (corresponding to the initial buckling load) varies depending on the processing accuracy of drilling and cutting.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned disadvantages of the prior art.

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention crushes a partition (rib) for forming a plurality of chambers (hollow portions or hollows) inside a hollow extruded mold member. The technical means of making at least one end of a single hollow or one chamber. The use of this means facilitates drilling, beading or fixing the mounting bracket to the end of the extrusion. When the strength member according to the present invention functions as an energy absorbing member, the end of the single hollow (chamber) has a function of lowering the yield point stress and the remainder having a plurality of chambers has a function of creating a plastic region having a high average stress. Thus, a high energy absorption is exhibited.

According to the present invention, the hollow portion formed by the frame is formed of an extruded member which defines a plurality of chambers by a partition integral with the frame, and the connecting portion between the partition at at least one end of the extruded member and the frame is elongated. A strength member is provided, wherein the strength member is partially sheared along a direction, and a partition of the sheared portion is squeezed into the interior of the extruded shape to form one chamber at the one end. Since the end portion of the strength member is a single chamber, it is possible to easily perform drilling and beading work on the frame by a common means, and furthermore, when functioning as an energy absorbing member, it can withstand an axial load. This is effective for lowering the yield point stress (equivalent to the initial buckling load). In addition, the remainder having a plurality of chambers is effective in creating a plastic region with a high average stress depending on the shape and number of the chambers against an axial load.

[0010] Preferably, an external force is applied so that an end portion (a portion of one chamber) of the strength member buckles in a longitudinal direction earlier than another portion. Thus, when functioning as an energy absorbing member, it is possible to efficiently create the above-described plastic region where the yield point stress is reduced and the energy absorption amount is large.

The end forming one chamber is bent inward or outward, or holes or beads are provided at the end. This facilitates attachment to other members, and when functioning as an energy absorbing member, the value of the yield point stress corresponding to the initial buckling load can be selected as the initial value.

The strength member according to the present invention functions as an energy absorbing member exhibiting an effective energy absorbing ability as a crash box connecting the reinforce of the bumper and the side member of the vehicle body, but of course absorbs energy such as impact. It can be used as a frame member of a vehicle body as well as other uses that require the above.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a part of an extruded aluminum alloy material 1 constituting an example of an energy absorbing member which is one embodiment of a strength member of the present invention. The illustrated example 1 has a cross-sectional shape in which a cross-shaped partition 3 is integrally formed in a rectangular frame 2 to form a plurality of chambers (hollows or hollows) 4. It is not limited to. The chamber 4 may be shaped like three cross sections or shaped like two cross sections.

The outside of the extrusion 1 is surrounded by a mold (not shown), and the punch 5 is pushed downward from above, whereby the partition 3 is crushed inward. In response to the downward movement of the punch 5, a shearing force acts on the joint surface between the inner wall surface of the frame 2 and the edge of the partition 3, and the edge of the partition 3 peels off from the inner wall surface of the frame 2. While being folded and folded, it is folded and housed inside the extrusion 1. As a result, as shown in FIG. 3, an energy absorbing member 7 having one end as one chamber 6 is formed by the extruded mold 1. FIG. 2 is a top view of a state where a part of the partition 3 overlaps the waveform.

[0015] JIS standard having a hollow portion with a cross section
A6063 T5 extruded aluminum alloy material (Frame 2 is 1.7m thick
m, the thickness of the partition 3 is 2.4 mm, and the outer dimensions are 60 × 10
0 mm) from above, a load of about 500 kg to about 1 ton was applied from above to crush the partition 3. As a result, one chamber 6 having a depth of 30 mm shown in FIGS. 1 to 3 was obtained.

When a compressive load is applied to the energy absorbing member 7 shown in FIGS. 1 to 3 in the axial direction, the end having one chamber (single hollow) 6 undergoes initial buckling deformation, and the yield point stress is reduced. As shown by the solid line in FIG. 4, the plastic deformation of the remaining portion having the plurality of chambers 4 which is considerably lower than the value shown by the conventional dotted line, and forms a plastic deformation region which is almost similar to the conventional one. For this reason, it is possible to ensure a high energy absorption without showing a high yield point stress.
A material other than the Al alloy material can be used as the extruded material 1. The cross-sectional shape and material of the extruded die 1 and the thickness of the frame 2 and the partition (rib) 3 may be selected in consideration of the necessary energy absorption and yield point stress.

FIG. 5 shows an application example of the energy absorbing member 7 to a vehicle. In this example, the energy absorbing member 7 is used as a crash box 8. The front parts of the pair of crash boxes 8 are fixed to both ends of the bumper reinforcement 9 at the front part of the vehicle. The rear portion of the crash box 8 contacts the left and right brackets 11 of the substantially square radiator support 10 having an upper frame and a lower frame, which extend in the vehicle width direction. The bracket 11 of the radiator support 10 and the rear part of the crash box 8 are bolted to a bracket 12 which forms a part of the body of the vehicle and is fixed to a front end of a side member 13 extending rearward from left and right positions of the body. .

The operation when the energy absorbing member 7 is used as the crash box 8 shown in FIG. 5 will be described.
When an impact force is applied to the bumper from the front due to a vehicle collision or the like, the impact force is transmitted from the bumper reinforcement 9 to the crash box 8 and then to the side member 1.
3 to the vehicle body. At this time, one of the crash boxes 8 applied as a strength member of the present invention absorbs impact energy by buckling deformation due to a load applied in the axial direction, thereby minimizing adverse effects on occupants and damage to the vehicle body. It works hard to stop. The amount of energy absorption at this time is as shown by the solid line in FIG.

The energy absorbing member 7 shown in FIGS.
The work for diversion to the crash box 8 will be described. In the example shown in FIG. 6, four (preferably corner) slits 14 are formed in the frame 2 of one chamber 6 at the end of the energy absorbing member 7 in the vertical direction. Next, as shown in FIG. 7, the four pieces 15 defined by the slits 14 are bent outward, and a screw hole 16 is formed in each piece 15. Each piece 15 having a screw hole 16 is bolted to the rear surface of the bumper reinforcement 9 by using the work hole 17 on the front surface of the bumper reinforcement 9. Only the slit 14 is inserted into the frame 2 and the piece 1 for attachment to the bumper reinforcement 9
5 can easily be applied to the crash box 8 of the energy absorbing member 7.

The depth of the slit 14 determines the capacity of one chamber 6 at the end of the crush box 8, thereby changing the peak value of the yield point stress corresponding to the initial buckling load.

In the example shown in FIG. 8, a U-shaped cut 18 is formed facing the portion of the frame 2 forming one chamber 6 of the energy absorbing member 7, and the adjacent facing portion 19 is folded inward to crash. Box 8. As shown in FIG. 9, a screw hole 20 is made in a portion 19 folded inward of the crash box 8, and this portion 19 is brought into contact with the rear surface of the bumper reinforcement 9, so that the working hole 17 and the screw hole 2 are formed.
Using 0, the crush box 8 is bolted to the rear surface of the bumper reinforcement 9. Also in this example, it is possible to make the crush box 8 in which the bumper reinforcement 9 can be easily mounted only by inserting the cut 18 into the end of the energy absorbing member 7.

8 and 9, the capacity of one chamber 6 is determined by the depth of the cut 18 so that the peak value of the yield point stress corresponding to the initial buckling load can be selected. 4 can secure the amount of energy absorption shown by the solid line. In the examples shown in FIGS. 7 and 9, the radius R of the bent portions of the mounting pieces 15 and 19 is preferably set to 50 to 10 mm.

In the illustrated example, one chamber 6 is provided at one end of the extrusion 1, but one chamber 6 may be provided at both ends. When used as the crash box 8, the radiator support 10 is attached to the bracket 11. 15 pieces for mounting
Alternatively, an inward folded portion 19 can be used.

The example shown in FIG. 10 is an example in which the partition at the end of the bumper reinforcement 9 having a plurality of chambers is crushed by the method shown in FIGS. By using one chamber 6, a large hole 21 can be formed in the wall, and a jig can be inserted into the large hole 21 to perform punching. The hole 21 allows the front part of the crash box 8 to pass through the hole 21 and fix the front part to the inner wall surface of the bumper reinforcement 9.

The example shown in FIG. 10 is based on A7003 T5 of the JIS standard.
Of an aluminum alloy extruded material (the thickness of the frame 2 is 2.5 mm, the thickness of the partition 3 is 1.2 mm, and the outer dimensions are 60 × 100 mm) from the upper side by a press machine from 500 kg to 1 kg.
The partition 3 is crushed by applying a load of about ton. The depth of one chamber 6 is 50 mm.

In the example shown in FIG. 11, when a load greater than a set value is applied to a member that is difficult to break at the root, a bent portion is formed at a portion other than the root. In this example, one room 6
A bead, a notch, or a small slit 22 facing the portion of the frame 2 for making a fold is formed as a break point.
As described above, the working of the portion of the frame 2 forming one chamber 6 is easy, and the strength of the extruded material 1 is maintained by the partition 3 in the remaining portion.

[Brief description of the drawings]

FIG. 1 is a view showing a work of crushing an end portion of a hollow extruded material having a plurality of chambers into a partition (rib).

FIG. 2 is a plan view of a partition (rib) that has been pressed.

FIG. 3 is a partial perspective view of an example in which an end of an extruded mold member is formed into one chamber.

FIG. 4 is a graph showing a relationship between an axial compressive load and a displacement (stroke).

FIG. 5 is a perspective view showing a front portion of the vehicle.

FIG. 6 is a perspective view showing a state where a slit is formed in the frame.

FIG. 7 is a perspective view showing an outwardly protruding mounting piece and a bumper reinforcement;

FIG. 8 is a perspective view showing an example in which a cut is made in a frame.

FIG. 9 is a perspective view showing a mounting piece bent inward and a bumper reinforcement;

FIG. 10 is a perspective view showing an example in which the end of the bumper reinforcement is formed into one chamber.

FIG. 11 is a perspective view showing an example of forming a break point.

[Explanation of symbols]

 DESCRIPTION OF REFERENCE NUMERALS 1 Extrusion member 2 Frame 3 Partition 4, 6 chamber 7 Energy absorbing member (strength member) 8 Crash box 15, 19 Mounting piece 16, 20 Mounting hole

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Shinichi Haneda 2-1-1 Asahi-cho, Kariya-shi, Aichi Aisin Seiki Co., Ltd. (72) Inventor Kazuo Mori 2-1-1 Asahi-cho, Kariya-shi, Aichi Aisin Seiki (72) Inventor Kazunari Azuchi 12 Aisin Light Metal Co., Ltd. at 12 Nagoe, Shinminato City, Toyama Prefecture

Claims (5)

[Claims] 1. An extruded member for defining a hollow portion formed by a frame into a plurality of chambers by a partition integral with the frame, and a joining portion between at least one end of the extruded member and the frame is formed along a longitudinal direction. A strength member characterized in that a part of the part is sheared, and a partition of the sheared part is pressed into the interior of the extruded mold member to form one chamber at the one end. 2. An end portion of a frame forming one chamber constitutes an external force input portion, and the input external force causes the one end portion to buckle and deform in a longitudinal direction earlier than other portions. The strength member for a vehicle according to claim 1. 3. The strength member according to claim 1, wherein one end of the frame forming one chamber is bent inward or outward. 4. The strength member according to claim 1, wherein at least one hole or bead is provided at one end of a frame forming one chamber. 5. The vehicle according to claim 1, wherein one end of a frame forming one chamber is fixed to a bumper reinforcement of a vehicle and the other end is fixed to a side member of the vehicle. Strength member.