JP5455349B2 - Aluminum alloy extruded shape roll bending method and aluminum alloy extruded shape member - Google Patents

Description

  The present invention relates to a roll bending method of an aluminum alloy extruded shape, and an aluminum alloy extruded shape member produced by the roll bending method.

  In recent years, from the viewpoint of protecting the global environment, the weight reduction of automobiles is expected, and aluminum alloy extruded shapes are expected to be applied to automobile frames or energy absorbing members.

Aluminum alloy extruded shapes have the advantage of being able to have a closed cross-section in advance without joining, and energy absorption performance compared to a closed cross-section structure such as a substantially hat-type manufactured by press forming of steel plate materials. There is an advantage that it is excellent. Moreover, it is possible to easily provide the thickness distribution in the cross section, and by appropriately distributing the thickness, a product having high bending strength, rigidity, and energy absorption characteristics can be obtained with an equivalent weight.
For this reason, application to components and frames that absorb loads and absorb energy in the event of a collision, such as automotive door reinforcement, bumper reinforcement, and roof reinforcement, is advancing. Among them, JIS7000 series (Al-Zn-Mg- (Cu) series) aluminum alloys have high material strength and are expected as high-strength energy absorbing parts.

Aluminum alloys are characterized by high corrosion resistance as compared to conventionally used steel sheets, but stress corrosion cracking often occurs depending on conditions. In particular, the 7000 series aluminum alloy has a problem that this stress corrosion cracking is likely to occur.
Stress corrosion cracking depends on the residual stress generated when the material is processed, and is more likely to occur as the tensile residual stress is higher than the material strength. Aluminum alloy extruded profiles are often required to bend when applied to body frames, reinforcements, etc., and stress corrosion cracking may occur due to the residual stress after the bending. is there.

In the 7000 series or 6000 series aluminum alloy, development of a material composition or manufacturing method for the purpose of improving the stress corrosion cracking property has been performed (see Patent Documents 1 to 3).
However, even if these materials are used, depending on the processing conditions, tensile stress may partially remain and stress corrosion cracking may occur. On the other hand, there is a measure to reduce the residual stress by performing shot peening on the surface (see Patent Document 4), but there is a problem of cost increase due to post-processing addition.

  In general, countermeasures against stress corrosion cracking by heat treatment after processing are also performed. For example, if the material strength is increased by performing T5 or T6 treatment (aging treatment) after processing in a T1 tempered state with low yield strength, the ratio of the tensile residual stress to the material strength can be reduced. . In addition, the residual stress itself may be reduced by heat treatment at a higher temperature, but in this case, the strength of the material itself is also lowered, so the advantage of applying a high strength 7000 series or 6000 series aluminum alloy There is a problem that it disappears.

  In the case of post-processing heat treatment in the state of the T1 tempered material, there is an advantage that residual stress can be reduced as described above, but securing the product dimensional accuracy after processing becomes a problem. Extruded shapes produced hot are subject to variations in material strength, and the T1 tempered material has natural aging even at room temperature, so that the material properties change depending on the processing timing. For this reason, variations occur in the amount of spring back after processing, making it difficult to ensure dimensional accuracy. In particular, in a large R-bending product having a large bending radius, the amount of springback itself is large, and the variation width is also large.

There are various methods for bending extruded shapes such as press bending, pressing bending, tensile bending, and roll bending. Each of these bending methods has its own characteristics, and there are several methods for adjusting the processing conditions when the above-described material characteristic variation occurs. Various proposals (see Patent Documents 5 and 6) have also been made regarding the cross-sectional shape of an extruded profile used for bending.
In the case of press bending or pressing bending in which bending is performed by pressing a material against a bending mold, the tool itself is formed of a rigid body. For this reason, when material variation occurs during mass production, it is only possible to adjust by the amount of pressing of the punch tool or the bending angle, and it is difficult to adjust when R is entirely provided in the longitudinal direction of the extruded profile.

In tension bending, in which bending is performed while applying tension to a material, there is an advantage that the amount of spring back itself is small by applying tension and it is easy to ensure dimensional accuracy. Further, when the material characteristics vary, it is possible to obtain a predetermined product by adjusting the springback amount by changing the tension applied during processing. However, in order to apply tension to the material, it is necessary to firmly clamp the end of the material, so it is necessary to cut and discard this part after bending, which reduces the yield of the material and the cost of adding the processing process Up is a problem.
On the other hand, in the case of roll bending, it is possible to manufacture products of different R by changing the push amount of the roll tool. In other words, if the material variation changes, it can be handled by changing the tool push-in amount, and the die cost is low. This is advantageous for products with large springback conditions.

Japanese Patent Publication No. 61-28744 JP 2001-207233 A JP 2001-240930 A JP-A-5-320838 Japanese Patent No. 3525979 Japanese Patent Laid-Open No. 2002-225651

However, the residual stress of a member subjected to roll bending is often higher than that of other bending methods such as the press bender, and particularly high in the case of a hollow shape material. The study revealed it. Therefore, as described above, the possibility that SCC (stress corrosion cracking) occurs is significantly increased.
In the present invention, the residual stress after bending is applied to an aluminum alloy extruded shape whose curvature is formed in the longitudinal direction by roll bending which is advantageous in terms of manufacturing cost and adjustment function for material variation at the time of manufacturing. It aims at obtaining the member made from an aluminum alloy extrusion shape material which is excellent in SCC (stress corrosion cracking resistance) performance by making small.

The roll bending method according to the present invention has a pair of flanges located inside and outside the bend and two or more webs connecting the flanges when viewed in a cross section perpendicular to the longitudinal direction, and a bend radius. In a roll bending method of an aluminum alloy extruded member having a projecting flange that is substantially perpendicular to the direction and projecting in both directions outside the web in the width direction, one surface of the projecting flange is supported by a receiving roll, and It is characterized in that it is bent while being loaded with a pressing roll on the other surface of both projecting flanges to give a curvature in the longitudinal direction.
This roll-bending member is mainly used as an energy absorbing member such as an automobile door reinforcing material, a bumper reinforcing material, or a roof reinforcing material, and in this case, a flange on the outer side of the bending is installed toward the outside of the vehicle body.

In the bending method according to the present invention, the following desirable embodiments can be mentioned.
(1) Both the projecting flanges are provided on the outermost bending side of the aluminum alloy extruded profile.
(2) In the cross section, the projecting flanges protrude outward in the width direction. In this case, further, in the cross section, when there is a portion located on the inner side (or outer side) than the two projecting flanges, the portion on which the receiving roll or pressing roll is located on the inner side (or outer side) than the two projecting flanges. Have a recess to store the

  The aluminum alloy extruded profile member having a curvature in the longitudinal direction according to the present invention has a pair of flanges located on the inner side and the outer side of the bend and two or more connecting these flanges when viewed in a cross section perpendicular to the longitudinal direction. And is formed of an aluminum alloy extruded shape member having a protruding flange that is substantially perpendicular to the bending radius direction and protrudes in both width directions outside of the web. It is supported and bent while being loaded on the other surface of both projecting flanges with a pressing roll, and can be manufactured by the above bending method.

According to the present invention, there are a pair of flanges positioned on the inner side and the outer side of the bend, and two or more webs connecting the flanges, and both directions that are substantially perpendicular to the bend radial direction and outside the web in the width direction. For the aluminum alloy extruded profile having a protruding flange projecting over, by supporting one surface of the both protruding flanges with a roll, and bending while loading with a pressing roll on the other surface of the protruding flange, An aluminum alloy extruded shape member having low tensile residual stress after bending and excellent SCC (stress corrosion cracking) resistance can be produced.
In addition, when the roll bent member according to the present invention is applied to an automobile energy absorbing member such as an automobile door reinforcement, a bumper reinforcement, or a roof reinforcement, an effect of improving performance by preventing breakage at the time of a collision. Can be obtained.
The present invention is most effective for application to a 7000 series (Al-Zn-Mg- (Cu)) aluminum alloy having high sensitivity to stress corrosion cracking, and when bending an aging treatment (T5, T6) material. Even so, the stress corrosion cracking resistance can be improved.

[Characteristics of conventional roll bending]
In the case of roll bending, the distance between the support points of the receiving roll and the pressing roll is short, and the tool load for performing predetermined bending is high compared to press bending or the like. For this reason, a high shear stress is applied to the material after passing through the receiving roll in accordance with a high tool load. Further, according to the new knowledge of the present inventor, the tool load from the pressing roll is also applied as a compressive stress in the longitudinal direction of the shape member (see FIG. 12 described later). It will be responsible for stress.

  FIG. 11 shows a pair of flanges (bending outer flange 2 and bending inner flange 3) located on the bending inner side and the bending outer side, two webs 4 and 5 connecting the flanges 2 and 3, and a web connected to the flanges 2 and 3. 4 shows a conventional method in which an aluminum alloy extruded profile 1 composed of left and right projecting flanges 6 to 9 (which can be said to be part of the flanges 2 and 3) projecting outward in the width direction from 4 and 5 is roll-bended. As shown in FIG. 11, the bending inner surface of the bending inner flange 3 of the aluminum alloy extruded profile 1 is supported by the feeding roll 11 and the receiving roll 12, and the bending outer surface of the bending outer flange 2 is supported by the feeding roll 11 and the receiving roll 12. Is sandwiched between feed rolls 13 and 14 installed immediately above, and is loaded on the outer surface of the bent outer flange 2 with a pressing roll 15, and the aluminum alloy extruded profile 1 passes between these rolls in the direction of the arrow. Bending is performed. The receiving roll 12 receives the load of the pressing roll 15 to support the bending of the aluminum alloy extruded shape 1, and the feeding roll 13 has an action of receiving the reaction force. In addition, 16 is a roll support part.

FIG. 12 shows a schematic diagram of the profile longitudinal stress distribution of the bent inner flange 2 and the bent outer flange 3 when the aluminum alloy extruded profile 1 (hollow profile) is roll-bent by the apparatus shown in FIG. In the figure, X is a position along the longitudinal direction of the aluminum alloy extruded profile 1, A is a contact portion of the receiving roll 12, and B is a contact portion of the pressing roll 15.
As shown in FIG. 12, the aluminum alloy extruded shape member 1 subjected to the bending process receives the largest bending moment immediately above the receiving roll 12, compresses the bending inner flange 3, and applies tensile bending stress to the bending outer flange 2. Furthermore, the absolute value of the compressive stress applied to the bending inner flange 3 is higher than the absolute value of the tensile stress applied to the bending outer flange 2 by applying the above-described shape member longitudinal direction compressive stress.

In the part which passed the receiving roll 12, the webs 4 and 5 are shear-deformed, and the compressive stress in the longitudinal direction of the profile applied to the bending inner flange 3 is suddenly unloaded and turned to tensile stress. As the bending stress is unloaded elastically as it comes closer to the contact portion with the pressing roll 15, the tensile stress generated in the bending inner flange 3 further increases and remains as it is after passing through the pressing roll 15. It will be. For this reason, the conventional roll bending process has a problem that a high tensile stress remains in the bending inner flange 3 and the risk of stress corrosion cracking increases.
Particularly in a hollow part such as an aluminum alloy extruded shape 1, since the thickness of the webs 4 and 5 is smaller than the width of the flanges 2 and 3, shearing deformation of the webs 4 and 5 is likely to occur, and after passing through the receiving roll 12 The stress change at the timing when the compressive stress is unloaded is large, and the tensile residual stress becomes large. This is a new finding of the present inventors.

[Roll bending according to the present invention]
FIG. 1 shows a typical example of a roll bending process according to the present invention (the same numbers as those in FIG. 11 are used for substantially the same parts for the aluminum alloy extruded shape and each roll). As shown in FIG. 1, the bending inner surfaces 6a and 7a of the left and right protruding flanges 6 and 7 on the outermost bending side of the aluminum alloy extruded profile 1 are supported by a feed roll 11 and a receiving roll 12, and the bending outer flange 2 ( The feed rolls 13 and 14 installed just above the rolls 11 and 12 are brought into contact with the bending outer surface of the protruding flanges 6 and 7, and the bending outer surface of the bending outer flange 2 (of the protruding flanges 6 and 7 is included). Bending is performed by passing the aluminum alloy extruded profile 1 in the direction of the arrow between these rolls while pressing the outer bending surfaces 6b and 7b) with the pressing roll 15.

In the example of FIG. 1, the projecting flanges 6 and 7 are projected most outward in the width direction in the cross section perpendicular to the extrusion direction of the aluminum alloy extruded profile 1. Further, the feed rolls 13 and 14 and the press roll 15 are rolls having a uniform peripheral surface, but the feed roll 11 and the receiving roll 12 have the same shape and have a small-diameter portion 17 at the center of the peripheral surface. The large-diameter portions 18 and 19 are provided, and a recessed portion 21 is formed between the large-diameter portions 18 and 19. The recessed portion 21 accommodates a portion positioned on the bending inner side of the protruding flanges 6 and 7 of the aluminum alloy extruded profile 1, and the peripheral surfaces of the large diameter portions 18 and 19 are bent inner surfaces 6 a and 7 a of the protruding flanges 6 and 7. Support. The aluminum alloy extruded profile 1 is fed forward with the projecting flanges 6 and 7 sandwiched between the feed roll 11, the receiving roll 12 and the feed rolls 13 and 14.
Since the receiving roll 12 supports only the bent inner surfaces 6a and 7a of the protruding flanges 6 and 7, the load applied from the pressing roll 15 is not transmitted to the webs 4 and 5, but the protruding flanges 6 and 7 are Via the receiving roll 12.

As shown in FIG. 1, the roll bending process according to the present invention includes a pressing roll 15 for loading and a receiving roll 12 for supporting the load on the same protruding flanges 6 and 7, compared to the conventional roll bending process. The protruding flanges 6 and 7 that are in contact with these roll tools are bent, and the bending is performed by causing other portions of the cross section of the aluminum alloy extruded profile 1 to follow this deformation. Yes.
In the example of FIG. 1, the receiving roll 12 is brought into contact with the bent inner surfaces 6a and 7a of the protruding flanges 6 and 7, and the pressing roll 15 is brought into contact with the bent outer surfaces 6b and 7b of the same protruding flanges 6 and 7. Depending on the roll arrangement of the roll bending process, conversely, the receiving roll may be brought into contact with the bent outer surface of the protruding flange, and the pressing roll may be brought into contact with the bent inner surface of the same protruding flange (see FIG. 3).
In the case of conventional roll bending, the tool load applied from the pressing roll 15 is transmitted to the bending inner flange 3 via the webs 4 and 5, so that the webs 4 and 5 are easily sheared. On the other hand, in the case of the present invention, the receiving roll 12 and the pressing roll 15 which are the support point and the load point are brought into contact with the same protruding flanges 6 and 7 so that the load is not transmitted to the webs 4 and 5. The residual stress can be reduced by suppressing the effect of this shear deformation.

FIG. 2 shows another example of the roll bending process according to the present invention (the aluminum alloy extruded shape member and each roll are denoted by the same reference numerals as those in FIG. 1 for substantially the same parts). In the roll bending process shown in FIG. 1, the contact position of the feed roll 11, the receiving roll 12 and the feed rolls 13 and 14 with the aluminum alloy extruded profile 1 is set to the same position in the longitudinal direction of the aluminum alloy extruded profile 1. However, in the roll bending process shown in FIG. 2, the feed roll 11, the receiving roll 12, and the feed rolls 13 and 14 are arranged in a staggered manner. The only difference between the two methods is this roll arrangement.
In the example of FIGS. 1 and 2, the feed roll 11 and the receiving roll 12 and the feed rolls 13 and 14 are shown with the same diameter and the same shape, respectively, but need not necessarily have the same diameter and the same shape. . Since the bending process is performed between the receiving roll 12 and the pressing roll 15, if these two rolls satisfy the requirements of the present invention, the diameters and shapes of the feed rolls 11, 13, and 14 are determined according to the processing requirements and device constraints. It may be selected according to convenience.

FIG. 3 shows still another example of the roll bending process according to the present invention (for the aluminum alloy extruded shape and each roll, the same reference numerals as those in FIG. 1 are used for substantially the same parts). This roll bending process is a three-roll type roll bending process in which a pressing roll 15 is disposed between two receiving rolls 12A and 12B. The peripheral surfaces of the receiving rolls 12A and 12B have a uniform diameter and support the bending outer surface of the bending outer flange 2 (the bending outer surfaces 6b and 7b of the projecting flanges 6 and 7). It has a large diameter part on the left and right (same structure as the receiving roll 12 in FIG. 1B), and the peripheral surface of the large diameter part is in contact with the bent inner surfaces 6a and 7a of the projecting flanges 6 and 7 for loading. ing. In addition, a recess located between the large diameter portions of the pressing roll 15 accommodates a portion located on the bending inner side of the protruding flanges 6 and 7 of the aluminum alloy extruded profile 1. The only difference from the processing method of FIG. 1 is this roll structure and roll arrangement.
In the processing method of FIGS. 1 and 2, the receiving roll 12 is disposed on the inner side of the bending and the pressing roll 15 is disposed on the outer side of the bending. However, the processing method of FIG.

In the example of FIGS. 1 to 3, the protruding flange where the receiving roll and the pressing roll contact is provided at a position (bending outermost position) connected to the bending outer flange of the aluminum alloy extruded profile. , Anywhere inside the cross section of the bent inner end, the bent outer end, and the middle part thereof, and by bending the press roll and support roll in contact with the same flange, at least due to the shear deformation of the webs 4, 5 An increase in residual stress can be suppressed.
However, in order to reduce the residual stress, it is desirable to provide it at a position close to the bent outer flange. In bending work without considering the influence of shear deformation, the residual stress distribution after unloading of bending stress is a compressive stress in the bending outer flange and a tensile stress in the bending inner flange. Since the projecting flange in contact with the presser roll is also subjected to compressive stress in the longitudinal direction of the profile, after passing through the presser roll, in addition to the stress caused by unloading the bending stress in the previous period, the longitudinal direction compression of the profile Tensile stress resulting from stress unloading is applied. For this reason, when the bending stress is unloaded, the bending stress (bending outside the bending neutral axis) where the compressive stress is generated is more preferable than the bending inner side where the tensile stress is generated (bending inner side than the bending neutral axis). Residual stress can be further reduced by providing a protruding flange on the outside.
When the protruding flange is provided on the outermost side of the bending, the thickness of the cross section is distributed to a position farther from the bending neutral axis, so if the bending rigidity and bending strength are equal, the product will be lighter. The desirable effect that it can be obtained is also obtained, and when a bent product is used as an energy absorbing member of an automobile as described later, the collision performance can be improved.

Moreover, in the example of FIGS. 1-3, although the protrusion flange which a receiving roll and a press roll contact is provided in the both sides of the closed cross-section part which a pair of flange and two webs make, this closed cross-section part is not necessarily rectangular. There is no need, and one or two or more medium webs (medium ribs) may be appropriately formed between the two webs in view of the required performance.
In addition, about the protrusion flange which a receiving roll and a press roll contact, in order to receive the load at the time of a bending process efficiently, it is desirable that it is substantially perpendicular | vertical with respect to the bending radial direction.

4 to 6 show still another example of the roll bending process according to the present invention (for the aluminum alloy extruded profile and each roll, the same reference numerals as those in FIG. 1 are used for substantially the same parts. ). Further, it is assumed that the arrangement of each roll and the point that each roll is cantilevered are the same as those in FIG.
The bending process of FIG. 4A is as follows: (1) The protruding flanges 6 and 7 of the aluminum alloy extruded profile 1 are not connected to both sides of the bending outer flange 2 and are closer to the bending inner side than the bending outer flange 2. (2) The pressing roll 15 has a small diameter portion 22 at the center of the peripheral surface, large diameter portions 23 and 24 on the left and right sides thereof, and a recess between the large diameter portions 23 and 24. A portion 25 is formed, and a portion located outside the protruding flanges 6 and 7 of the aluminum alloy extruded shape member 1 is accommodated in the recessed portion 25, and the peripheral surfaces of the large diameter portions 23 and 24 are formed on the protruding flanges 6 and 7. (3) The feed rolls 13 and 14 (not shown) have a small-diameter portion at the center of the peripheral surface and have large diameters on the right and left sides, respectively. And a recess is formed between the large diameter portions, the recess A portion of the aluminum alloy extruded shape member 1 located on the bent outer side from the protruding flanges 6 and 7 is accommodated, and the peripheral surface of the large diameter portion is in contact with the bent outer surfaces 6b and 7b of the protruding flanges 6 and 7. This is different from the bending process of FIG. The recessed portion 21 of the receiving roll 12 accommodates a portion located on the bending inner side of the projecting flanges 6 and 7 of the aluminum alloy extruded profile 1 as in the bending process of FIG.

  The bending process of FIG. 4 (b) is that (1) the protruding flanges 8 and 9 on the inner side of the bend project from the protruding flanges 6 and 7 on the outer side of the aluminum alloy extruded profile 1 in the cross-section. (2) The receiving roll 12 (also a feed roll 11 not shown) is a roll having a uniform peripheral surface and supports the bending inner surface of the bending inner flange 3 (the bending inner surfaces 8a and 9a of the protruding flanges 8 and 9). (3) The pressing roll 15 has a small diameter portion 22 at the center portion of the peripheral surface, large diameter portions 23 and 24 on the left and right sides thereof, and a recessed portion 25 between the large diameter portions. A portion of the aluminum alloy extruded profile 1 positioned on the outer side of the bent flanges 8 and 9 is accommodated in the recessed portion 25, and the peripheral surfaces of the large diameter portions 23 and 24 are bent outer surfaces of the protruding flanges 8 and 9. The point where 8b and 9b are pressed and loaded ( ) The feed rolls 13 and 14 (not shown) have a small-diameter portion at the center of the peripheral surface, have large-diameter portions on the left and right sides thereof, and a recess is formed between the large-diameter portions, like the press roll 15. A portion of the aluminum alloy extruded profile 1 located on the bent outer side from the protruding flanges 8 and 9 is accommodated in the recessed portion, and the peripheral surface of the large diameter portion contacts the bent outer surfaces 8b and 9b of the protruding flanges 8 and 9. This is different from the bending process of FIG.

  5A, (1) an intermediate web 26 is added between both webs of the aluminum alloy extruded profile 1, and the protruding flanges 6 and 7 on the outer side of the bending are positioned on the outer side of the bending outer flange 2. And (2) the presser roll 15 has a large diameter portion 28 at the center of the peripheral surface and small diameter portions 29 and 30 on the left and right sides thereof. The large-diameter portion 28 is fitted in the concave portion 27 of the aluminum alloy extruded profile 1, and the peripheral surfaces of both small-diameter portions 29, 30 are loaded while pressing the bent outer surfaces 6b, 7b of the projecting flanges 6, 7. (3) The feed rolls 13 and 14 (not shown) have a large-diameter portion at the center of the peripheral surface and small-diameter portions on the left and right sides thereof, similar to the press roll 15, and the concave portion of the aluminum alloy extruded profile 1. 27 is fitted with the large diameter portion, and the peripheral surface of the small diameter portion protrudes. Bending the outer surface 6b of the flange 6, in that in contact with 7b, different from the bending FIG. The peripheral surfaces of the feed rolls 13 and 14 and the pressing roll 15 may have a uniform diameter.

The bending process of FIG. 5B differs from the bending process of FIG. 1 only in that an intermediate web 26 is added between both webs of the aluminum alloy extruded profile 1.
5 (c), the bending outer flange 2 and the webs 3 and 4 of the aluminum alloy extruded profile 1 are inclined so that the closed cross section is not rectangular, and the protruding flanges 6 and 7 on the outer side are bent. It is located on the outer side of the bent outer flange 2 and has a concave portion 27 formed on the outer side of the bent outer flange 2, and (2) the small diameter portion 17 and the large diameter portion 17 on the peripheral surface of the receiving roll 12 (also the feed roll 11 not shown). The inner walls 31, 32 connecting the diameter portions 18, 19 are inclined inward in accordance with the inclination of the webs 3, 4 of the aluminum alloy extruded profile 1, and the indented portion 21 is narrowed inward. This is different from the bending process of No. 1.

6A, (1) the ribs 33 and 34 in the bending inner direction are formed at the tips of the projecting flanges 6 and 7 of the aluminum alloy extruded profile 1, and (2) the receiving roll 12 1 in that the recesses 35 and 36 are formed in the outer end corners of the large-diameter portions 18 and 19 and the ribs 33 and 34 located on the bending inner side of the protruding flanges 6 and 7 are avoided. Different from processing.
The bending process of FIG. 6 (b) consists of (1) flanges 3A and 3B in which the bent inner flange 3 of the aluminum alloy extruded profile 1 is divided into left and right, and the bent outer flange 2 and the flange 3A are connected to the webs 4 and 38. And the webs 5 and 39 are connected to the flange 2 and the flange 3B, the open section 37 is formed at the center, and the closed sections 41 and 42 are formed on both sides of the open section 37, (2) A large-diameter portion 43 is formed at an intermediate portion between the large-diameter portions 18 and 19 of the receiving roll 12 (also the feed roll 11 not shown), and the recessed portions 21A and 21B are provided between the large-diameter portions 18 and 19 and the large-diameter portion 43. The large-diameter portion 43 is formed in contact with the bending inner surface 2a of the bending outer flange 2 within the open cross-section portion 37 to support the aluminum alloy extruded profile 1, and the closed cross-section portions 41 and 42 are recessed portions 21A and 21B, respectively. In terms of being housed in Bending and different.
6 (c), (1) the protruding flanges 6 and 7 of the aluminum alloy extruded profile 1 are not flat but inclined inwardly, (2) a receiving roll 12 (a feed roll 11 (not shown)). The peripheral surface of the large-diameter portions 18 and 19 has a truncated conical shape in accordance with the inclination of the protruding flanges 6 and 7, and (3) the peripheral surface of the pressing roll 15 is also bent outside of the protruding flanges 6 and 7. It differs from the bending process of FIG. 1 in that both side portions in contact with the surfaces 6b and 7b are formed in a truncated cone shape in accordance with the inclination of the protruding flanges 6 and 7.

  FIG. 7 shows still another example of the roll bending process according to the present invention (for the aluminum alloy extruded profile and each roll, the same reference numerals as those in FIG. 3 are used for substantially the same parts). This roll bending process uses a three-roll type roll bending process (see FIG. 3) in which a pressing roll 15 is disposed between two receiving rolls 12A and 12B, and an aluminum alloy extruded form shown in FIG. 4B. The material (the projecting flanges 8 and 9 on the inner side of the bend protrude from the projecting flanges 6 and 7 on the outer side in the cross section of the aluminum alloy extruded profile 1 to the outermost side in the width direction) is bent. The receiving rolls 12A and 12B have a small-diameter portion at the center and a large-diameter portion on the left and right sides thereof (the same structure as the pressing roll 15 in FIG. 3), and the peripheral surface of the large-diameter portion is the outer side of the protruding flanges 8 and 9 The surfaces 8b and 9b are supported, and the circumferential surface of the pressing roll 15 has a uniform diameter, and is in contact with and loaded on the bending inner surface of the bending inner flange 3 (particularly the protruding flanges 8 and 9).

  In addition, in the bending process of FIG. 1, 2, 5 (a)-(c), 6 (a)-(c), the part located inside bending from the protrusion flanges 6 and 7 of the aluminum alloy extrusion shape material 1, In the bending portion of FIG. 3, the portion positioned on the bending inner side of the protruding flanges 6 and 7 is stored in the recessed portion of the pressing roll 15, and stored in the recessed portion 21 (or the recessed portions 21 </ b> A and 21 </ b> B) of the receiving roll 12. In the bending process of FIG. 4 (a), the portion located on the bending inner side from the projecting flanges 6 and 7 is accommodated in the recessed portion 21 of the receiving roll 12, and the portion located on the bending outer side from the projecting flanges 6 and 7 is In the bending process shown in FIG. 4B, the portion positioned on the outer side of the protruding flanges 8 and 9 is accommodated in the depression 25 of the pressing roll 15 and is bent as shown in FIG. In processing, the protruding flange 8, More bending a portion located outside the receive rolls 12A, it is housed in the recessed portion of 12B.

FIG. 8 shows still another example of the roll bending process according to the present invention (for the aluminum alloy extruded profile and each roll, the same reference numerals as those in FIG. 1 are used for substantially the same parts). Further, it is assumed that the arrangement of each roll is the same as that in FIG.
The bending process of FIG. 8 includes (1) the protruding width of the protruding flanges 6 and 7 on the outer side of the aluminum alloy extruded profile 1 is smaller than the protruding width of the protruding flanges 8 and 9 on the inner side of the bending, and (2) FIG. Instead of the receiving roll 12 having the small-diameter portion 17 and the large-diameter portions 18 and 19, a pair of receiving rolls 12 and 12 having a uniform peripheral surface are arranged on both sides of the aluminum alloy extruded profile 1, and the protruding flanges 6 and 8 The receiving rolls 12 and 12 are inserted between the projecting flanges 7 and 9, and the bending inner surfaces 6 a and 7 a of the projecting flanges 6 and 7 are supported.

In addition, in the bending process of FIGS. 1-7, a recessed part is formed in a receiving roll or / and a pressing roll, a receiving roll and a pressing roll are made to contact the protruding flange which protruded the width direction outermost, and both said protruding flanges A receiving roll or / and a pressing roll was configured in a cantilever structure by accommodating a portion located on the bending inner side and / or outer side in the bending portion. For this reason, it is possible to simplify an apparatus structure. In addition, this configuration has an advantage that a motor required for driving the roll need only be provided on one side even when the bearings are provided on both sides of the roll and the both-side support is adopted.
On the other hand, as in the bending process of FIG. 7, a both-end type device having a pair of rolls as a receiving roll and / or a pressing roll can also be used.

[Application to energy absorbing members]
The roll-bending member (aluminum alloy extruded member) according to the present invention is a flange on the outer side when considering use as an energy absorbing member such as an automobile door reinforcement, a bumper reinforcement or a roof reinforcement. Will be installed facing the outside of the vehicle body (collision direction). This is because, in general, automobiles have a design that has a convex shape toward the outside of the vehicle body, and if the roll-bending member according to the present invention is adapted to this design, such an installation form naturally occurs. .
When the roll-bending member according to the present invention is applied to the above uses (mainly door reinforcing material, bumper reinforcing material, roof reinforcing material) according to this installation form, the following effects (1) to (3) are further obtained. be able to.

(1) The aluminum alloy extruded profile member according to the present invention has a curvature in the longitudinal direction and is disposed with the convex side (bending outer flange side) facing the outer side of the vehicle body. Since a compressive stress is generated in the axial direction of the extruded shape member, the tensile stress applied to the bent inner flange is reduced, and the fracture is less likely to occur.
(2) The aluminum alloy extruded profile member according to the present invention has a curvature in the longitudinal direction, and has a curvature in the longitudinal direction by being installed with the convex side (bending outer flange side) facing the outer side of the vehicle body. Compared to a straight member that does not, it has a structure that protrudes to the front side of the collision, has an advantage of quicker contact with the other side of the collision, and can increase the energy absorption stroke. This makes it easier to suppress damage to the vehicle body by increasing the amount of energy absorption, and when compared with the same amount of energy absorption, the collision will be faster (because it is convex toward the outside of the vehicle body), so that when energy absorption ends The amount of entering the vehicle body can be suppressed.
(3) By providing a protruding flange that protrudes to the outermost side in the width direction on the outermost side of the bend, it is possible to widen the range in contact with the flange at the time of collision, and widen the corresponding range when the collision position is different. it can.

  In addition, when the aluminum alloy extruded member according to the present invention is applied to such an energy absorbing member, the web for connecting the flange inside and outside the bending is responsible for the load at the time of collision, and therefore is provided substantially parallel to the collision direction. It is desirable.

FIG. 10 shows the result of bending analysis using a T5 treated material (yield strength: 450 MPa) of a 7000 series aluminum alloy extruded shape having a cross-sectional shape (unit: mm) shown in FIG. A general-purpose static implicit software ABAQUS was used for the bending analysis.
FIG. 10 is a graph showing the relationship between the product bending radius of the aluminum alloy extruded profile and the maximum residual stress of the bent inner and outer flanges. In the figure, the horizontal axis indicates the bending radius determined from the shape of the outer surface of the aluminum alloy extruded profile, and the vertical axis indicates the residual stress in the longitudinal direction of the inner or outer surface of the bending where the residual stress is greatest.
The values when the conventional roll bending process is performed (see FIG. 11) are indicated by solid lines and broken lines with a ■ mark, and when the roll bending process of the present invention is applied with the protruding flange as the outermost bending position (see FIG. 11). 1) is indicated by a solid line and a broken line marked with ◆, and the roll bending process of the present invention is applied with the cross-section reversed and the protruding flange bent to the innermost side (see FIG. 4B). Values are indicated by solid and dashed lines with a circle.

  As shown in FIG. 10, when the conventional roll bending process is applied (marked with ■), a high residual stress is generated in the bending inner flange. On the other hand, when the roll bending process of the present invention is applied with the protruding flange as the outermost bending side (♦ mark), a residual tensile stress is generated in the bent outer flange, and the value is It can be seen that it is significantly lower than the roll bending method. In addition, the residual stress (○ mark) when the roll bending process of the present invention is applied with the protruding flange at the innermost bending side is less effective, but compared with the case of applying the conventional roll bending process (marked with ■). Thus, the tensile residual stress is low, and the residual stress reduction effect by the roll bending process of the present invention is recognized.

It is the side view (a) explaining the bending method of the aluminum alloy extrusion shape material which concerns on this invention, and its AA sectional drawing (b). It is a side view explaining the other bending method which concerns on this invention. It is a side view explaining the further bending method which concerns on this invention. It is sectional drawing explaining the further another bending method which concerns on this invention. It is sectional drawing explaining the further another bending method which concerns on this invention. It is a side view explaining the further bending method which concerns on this invention. It is sectional drawing explaining the further another bending method which concerns on this invention. It is sectional drawing explaining the further another bending method which concerns on this invention. It is sectional drawing of the aluminum alloy extrusion shape material used for the Example of this invention. It is a graph which shows the value of the largest residual stress of the bending inner and outer flange with respect to the bending radius calculated | required by analyzing in the Example. It is the side view (a) explaining the bending method of the conventional aluminum alloy extrusion shape material, and its AA sectional drawing (b). It is a schematic diagram of the profile longitudinal direction position and profile longitudinal direction stress distribution in the conventional bending method.

Explanation of symbols

2,3 Flange 4,5 Web 6-9 Protruding flange 11,12 Receiving roll 13,14 Feeding roll 15 Holding roll 21,25 Recessed part

Claims (14)

When viewed in a cross section perpendicular to the longitudinal direction, it has a pair of flanges located inside and outside the bend, and two or more webs connecting the flanges, and is substantially perpendicular to the bend radial direction and wider than the web. In a roll bending method of an aluminum alloy extruded shape member having projecting flanges projecting outward in both directions, one surface of both projecting flanges is supported by a receiving roll, and a pressing roll is supported on the other surface of both projecting flanges A roll bending method for an aluminum alloy extruded shape, characterized in that bending is carried out while being loaded and a curvature is imparted in the longitudinal direction. 2. The roll bending method for an aluminum alloy extruded profile according to claim 1, wherein the two projecting flanges are provided on the outermost bending side of the aluminum alloy extruded profile. The method for bending a roll of an aluminum alloy extruded profile according to claim 1, wherein the projecting flanges protrude outward in the width direction in the cross section. 3. The aluminum alloy extruded profile roll bending method according to claim 2, wherein the projecting flanges project outward in the width direction in the cross section. 5. The aluminum alloy extruded profile roll according to claim 3, wherein the receiving roll or the pressing roll has a recessed portion that accommodates a portion of the cross section that is located on the bending inner side with respect to the protruding flanges. Bending method. 4. The roll bending process for an aluminum alloy extruded shape member according to claim 3, wherein the pressing roll or the receiving roll has a recessed portion that accommodates a portion positioned on the bending outer side of the protruding flanges in the cross section. Method. 7. The aluminum alloy extruded shape roll bending method according to any one of claims 1 to 6, wherein the aluminum alloy extruded shape is made of a JIS7000 series aluminum alloy. When viewed in a cross section perpendicular to the longitudinal direction, it has a pair of flanges located inside and outside the bend, and two or more webs connecting the flanges, and is substantially perpendicular to the bend radial direction and wider than the web. It is made of an aluminum alloy extruded shape having projecting flanges projecting outward in both directions, and supports one surface of both projecting flanges with a receiving roll, and loads the other surface of both projecting flanges with a pressing roll An aluminum alloy extruded member having a curvature in the longitudinal direction, characterized by bending. 9. The aluminum alloy extruded shape member having a longitudinal curvature according to claim 8, wherein the both projecting flanges are provided on the outermost bending side of the aluminum alloy extruded shape. 10. The aluminum alloy extruded member having a longitudinal curvature according to claim 8, wherein both the projecting flanges protrude outward in the width direction in the cross section. The said aluminum alloy extrusion shape material consists of JIS7000 type | system | group aluminum alloy, The aluminum alloy extrusion shape material member which has a curvature in the longitudinal direction described in any one of Claims 8-10 characterized by the above-mentioned. The use of the aluminum alloy extruded member is an energy absorbing member of an automobile, and the flange located on the outer side of the bend is installed toward the outer side of the vehicle body. An aluminum alloy extruded member having a curvature in the longitudinal direction. It is an aluminum alloy extruded member made by the roll bending method described in any one of claims 1 to 6 and having a curvature in the longitudinal direction, and its use is an energy absorbing member of an automobile, An aluminum alloy extruded member having a curvature in the longitudinal direction, wherein the flange located on the outer side of the bending is installed toward the outer side of the vehicle body. 14. The aluminum alloy extruded shape member having a longitudinal curvature according to claim 12 or 13, wherein the energy absorbing member is an automobile door reinforcing material, a bumper reinforcing material or a roof reinforcing material.

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