JP2017042771A - Roll molding method and roll molding apparatus for metallic material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable precise roll molding on a tapered raw material which varies in plate thickness lengthwise with simple, inexpensive constitution.SOLUTION: The present invention relates to a roll molding method for a plate-like metal material M' varying in plate thickness along a length, the roll molding method comprising a plurality of stages of roll molding processes a to m of sending the metal material M' to between a plurality of pairs of molding rolls RA1 to RA13, RB1 to RB13, and molding the materials in stages so that a cross-sectional shape orthogonal to the lengthwise becomes a predetermined shape having a curved corner part CR, and, in one or a plurality of stages of the successive roll molding processes k, l and m including the final stage m, molding the corner part CR with the molding roll pairs RA11 to RA13, RB11 to RB13 having radii of curvature of r3 to r5 at corner part smaller than a target radius of curvature rt at the corner part CR of the metal material M'.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a roll forming method and roll forming apparatus for a metal material in which a plate-shaped metal material is fed between a plurality of forming rolls and the cross-sectional shape of the metal material is formed stepwise into a predetermined shape. .

For example, when the flat strip-shaped metal material M shown in FIG. 1A is formed into a stringer member S of an aircraft having a bent cross-sectional shape shown in FIG. Forming is performed step by step through a plurality of roll forming steps shown in b) to (l).
The plurality of roll forming steps are performed by a roll forming apparatus called a roll forming line as disclosed in Patent Document 1. As shown in FIG. 1, the roll forming line is a forming line in which a plurality of forming rolls RA1 to RA13 having different cross-sectional shapes and RB1 to RB13 are arranged on the line. The metal material M is molded stepwise as it sequentially passes between the forming rolls RA1 to RA13 and RB1 to RB13.

  In the roll forming method disclosed in Patent Document 1, a pinch point of a material to be formed by upper and lower rolls is set at a boundary between a target forming region in a material width direction and a pre-formed region or an un-formed region, and the target forming region Is formed along the predetermined caliber of the upper roll on the inner side of the bend, and in particular, the lower roll is hardly brought into contact with the outer side of the target forming region.

  According to this roll forming method, the bending formability is remarkably improved, the occurrence of roll wrinkles, roll marks and buckling is prevented, the forming function in the breakdown forming part is enhanced, and the overall formability of the base plate is improved. It can be greatly improved.

JP 2012-6083 A

  As shown in FIG. 2 (a), a recent stringer member for aircraft uses a taper material M ′ whose thickness repeatedly changes in a taper shape along the longitudinal direction, as shown in FIG. 2 (b). It has come to be formed into a shape called a taper stringer. Such a taper stringer TS is designed to reduce the weight by keeping the plate thickness Tmax of the portion to be coupled with other members of the machine body large and minimizing the plate thickness Tmin of the other portions.

  When roll forming a material whose plate thickness changes in a taper shape along the longitudinal direction like the taper material M ′ described above, for example, the portion of the plate thickness Tmax and the portion of the plate thickness Tmin are similarly set to 90 °. When it is attempted to bend, even if the bending angle of the portion having the plate thickness Tmax is 90 °, the bending angle of the portion having the plate thickness Tmin is larger than 90 °. The reason is that the plate thickness Tmin has a smaller volume in which permanent distortion is accumulated than the plate thickness Tmax, so that springback is likely to occur.

  Therefore, such a taper material cannot be roll-formed with high accuracy. This problem is difficult to solve even by the roll forming method described in Patent Document 1.

  The present invention has been made in view of such circumstances, and a metal material that can accurately roll-form a taper material whose thickness changes along the longitudinal direction with a simple and inexpensive configuration. An object is to provide a roll forming method and a roll forming apparatus.

  In order to solve the above problems, the present invention employs the following means.

  That is, the metal material roll forming method according to the present invention is a plate-shaped metal material roll forming method in which the plate thickness varies along the longitudinal direction, and the metal material is placed between a plurality of forming roll sets. Feeding, having a multi-stage roll forming process in which the cross-sectional shape perpendicular to the longitudinal direction has a predetermined shape having a curved corner, and the final of the multi-stage roll forming processes In the one or a plurality of successive roll forming steps including a step, the corner portion is formed by a forming roll set having a corner radius of curvature smaller than a target radius of curvature at the corner portion of the metal material. It is characterized by that.

  According to the roll forming method of the metal material having the above configuration, in one or a plurality of successive roll forming steps including the final stage, the corner radius of curvature is smaller than the target radius of curvature at the corner of the metal material. The corner portion is formed by a forming roll set having

  Here, the bending angle of the metal material in the finishing process including the final stage is substantially equal to the target bending angle. For example, when a corner portion is formed by a forming roll set having a corner radius of curvature equivalent to a target radius of curvature at the corner portion of the metal material, the spring back is small in the portion where the metal material has a large plate thickness. , It is formed at an angle approximately equal to the target angle. However, since the springback is large in the thin part, the bending angle after molding becomes larger than the target angle.

  In the present invention, since the corner portion is formed by the forming roll set having a corner radius of curvature smaller than the target radius of curvature, a springback within an assumed range is generated in a thin portion of the plate thickness, and bending after forming is performed. The angle can be close to the target.

  Therefore, even for a taper material whose thickness changes in a taper shape along the longitudinal direction, the formability is changed according to the occurrence of springback depending on the thickness change direction, and the thin portion of the thickness is changed. The roll radius can be accurately formed by approximating the radius of curvature at the corner to the target radius of curvature.

  In addition, since the corner portion of the metal material is bent in a plurality of stages, the influence of the spring back can be reduced and the curvature radius accuracy of the corner portion can be increased. For these reasons, a taper material whose plate thickness varies in the longitudinal direction can be roll-formed accurately and stably with a simple and inexpensive configuration.

  In the metal material roll forming method, the roll forming step of forming with the forming roll set having the corner portion radius of curvature smaller than the target radius of curvature is performed a plurality of times, and at this time, from the front side to the back side The radius of curvature of the corner of the forming roll set is preferably decreased toward the front.

  According to the roll forming method of the metal material having the above-described configuration, the corner portion of the metal material is elastically deformed stepwise by a plurality of forming roll sets to a corner radius of curvature smaller than the target curvature radius. For this reason, it can suppress more effectively that a springback arises in a corner part.

  The roll forming apparatus according to the present invention is a roll forming apparatus that feeds a plate-shaped metal material between a plurality of stages of forming roll sets, and forms the cross-sectional shape of the metal material into a predetermined shape step by step. Among the plurality of forming roll sets, one or a plurality of continuous forming roll sets including the final forming roll set have corner portions curved in a cross section perpendicular to the longitudinal direction of the metal material. A convex forming part to be molded, and a concave forming part facing the convex forming part, and the corner radius of curvature of the convex forming part is for the springback after molding, The metal material is set to be smaller than a target curvature radius at the corner portion.

  According to the roll forming apparatus having the above configuration, in one or a plurality of successive roll forming steps including the final stage, forming having a corner radius of curvature smaller than a target radius of curvature at the corner of the metal material. Corner portions are formed by the roll set.

  For this reason, as in the case of the action and effect of the roll forming method described above, even in a thin metal material that is prone to spring back, bending at the corner is caused by the occurrence of a large spring back at the corner. It can suppress that an angle spreads more than a target angle. Thereby, even if it is a taper raw material which plate | board thickness changes along a longitudinal direction, for example, the thin part of the board | plate thickness can be roll-formed to a bending cross-sectional shape with sufficient precision.

  In the above roll forming apparatus, a plurality of the forming roll sets having the convex forming portion having the corner radius of curvature smaller than the target radius of curvature are provided, and the corner radius of curvature is changed from the front side to the rear side. It is preferable to make it small toward the side.

  According to the roll forming apparatus for a metal material having the above-described configuration, the corner portion of the metal material is elastically deformed stepwise by a plurality of forming roll sets to a corner radius of curvature smaller than the target radius of curvature. For this reason, it can suppress more effectively that a springback arises in a corner part.

  In the above-described configuration, one of the forming rolls that abuts on one surface of the metal material is provided concentrically with respect to one of the roll shafts, and abuts against the other surface of the metal material and the one of the forming rolls The other forming roll opposite to the other roll shaft is provided so as to be eccentric with respect to the other roll shaft, and the other forming roll provided to be eccentric is provided by a pressing roll that comes into contact with the outer peripheral portion thereof. You may make it press on the one said forming roll side provided concentrically.

  According to the above configuration, for example, even when the metal material is a taper material whose plate thickness repeatedly changes along the longitudinal direction, the metal material is formed while being pressed with a constant force without impairing the plate thickness of the metal material. can do. Thereby, the taper stringer of an aircraft etc. can be shape | molded and manufactured accurately.

  In the above configuration, the metal material may be a taper material whose plate thickness repeatedly changes in the longitudinal direction. As a result, it is possible to manufacture a part whose cross section changes, such as an aircraft taper stringer.

  As described above, according to the roll forming apparatus according to the present invention, it is possible to roll-form a taper material whose thickness changes in the longitudinal direction with high accuracy with a simple and inexpensive configuration.

(A)-(m) is sectional drawing which shows a roll forming process until a flat strip | belt-shaped metal material is shape | molded by the stringer member of an aircraft. (A) is a perspective view which shows the taper raw material which plate | board thickness changes in a taper shape along a longitudinal direction, (b) is a perspective view which shows the taper stringer roll-formed using the taper raw material of (a). FIG. It is a longitudinal cross-sectional view of the roll forming apparatus which concerns on embodiment of this invention. It is the IV section enlarged view in FIG. It is a longitudinal cross-sectional view which expands the V section in FIG. 4, and shows 1st Embodiment of this invention. It is a longitudinal cross-sectional view which shows 2nd Embodiment of this invention.

  Embodiments of the present invention will be described below with reference to the drawings.

[First Embodiment]
FIG. 3 is a longitudinal sectional view of the roll forming apparatus according to the embodiment of the present invention. The roll forming apparatus 1 includes, for example, a taper material M ′ (metal material) whose thickness changes repeatedly in a taper shape along the longitudinal direction shown in FIG. 2A, and a taper stringer shown in FIG. Can be molded into TS without difficulty. The roll forming apparatus 1 according to the present embodiment includes a final stage (m) among roll forming lines in which a plurality of forming rolls having different cross-sectional shapes shown in FIGS. The first stage molding (j) of the finishing steps (j) to (m) is performed.

  As shown in FIG. 3, the roll forming apparatus 1 includes two upper and lower horizontal roll shafts 7A and 7B. The two roll shafts 7A and 7B are engaged with each other by gears 8A and 8B fixed to the ends thereof. Then, for example, when a rotational driving force R is applied from a driving source such as an electric motor (not shown) provided on one roll shaft 7A, the two roll shafts 7A and 7B are interlocked with each other at a constant speed in opposite rotation directions. Rotate. That is, the roll shaft 7A is a drive shaft and the roll shaft 7B is a driven shaft.

  The roll shaft 7A and the roll shaft 7B are respectively provided with fixed rolls 11A and 11B (one forming roll) concentrically. These fixed rolls 11A and 11B rotate integrally with the roll shafts 7A and 7B, respectively. For example, the upper fixed roll 11B is a stepped roll.

The roll shaft 7A and the roll shaft 7B are provided with floating rolls 12A and 12B (the other forming roll) so as to be eccentric. These floating rolls 12A and 12B are rotatable relative to the roll shafts 7A and 7B, respectively.
For example, the floating roll 12A can move a little in the axial direction of the roll shaft 7A. The amount of movement is approximately the same as the maximum thickness Tmax of the taper material M ′, but may be larger.

The roll shaft 7A is provided with a fixed roll 11A and a floating roll 12A adjacent in the axial direction, and the roll shaft 7B is provided with a fixed roll 11B and a floating roll 12B adjacent in the axial direction.
The fixed roll 11A provided on the roll shaft 7A faces the floating roll 12B provided on the roll shaft 7B, and the fixed roll 11B provided on the roll shaft 7B faces the floating roll 12A provided on the roll shaft 7A. doing.

  That is, in this embodiment, the fixed roll 11A and the floating roll 12A provided on the roll shaft 7A constitute a combination roll RA10 that abuts one surface of the taper material M ′, and the fixed roll provided on the roll shaft 7B. The roll 11B and the floating roll 12B constitute a combination roll RB10 that comes into contact with the other surface of the tapered material M ′. The combination rolls RA10 and RB10 form a pair of forming rolls, and the taper material M 'is sent between the forming rolls RA10 and RB10 and roll-formed.

  4, the taper material M ′ (taper stringer TS) is sent and molded between the fixed roll 11A and the floating roll 12B and between the floating roll 12A and the fixed roll 11B. . The cross-sectional shape of the taper material M ′ is a shape bent in a crank shape (channel shape), between the side surface of the floating roll 12A and the side surface of the floating roll 12B, and between the side surface of the floating roll 12A and the side surface of the fixed roll 11B. A taper material M ′ is also sandwiched between them.

  As shown in FIGS. 3 and 4, clearances CA and CB are provided between the roll shaft 7A and the floating roll 12A and between the roll shaft 7B and the floating roll 12B, respectively. The floating rolls 12A and 12B can be eccentric with respect to the fixed rolls 11A and 11B by the clearances CA and CB. The sizes of the clearances CA and CB need to be larger than the difference between the maximum plate thickness and the minimum plate thickness of the taper material M ′. For example, when the maximum plate thickness of the taper material M ′ is 3 mm and the minimum plate thickness is 1 mm, the clearances CA and CB are set larger than the plate thickness difference of 2 mm.

As shown in FIGS. 3 and 4, one surface of the adjacent portion of the fixed rolls 11 </ b> A and 11 </ b> B and the adjacent floating rolls 12 </ b> A and 12 </ b> B, for example, the side surface of the fixed rolls 11 </ b> A and 11 </ b> B A plurality of (for example, eight) driving recesses 15 are formed.
Further, the same number of loosely fitted drive driving recesses 15 of the fixed rolls 11A and 11B is provided on the other surface of the adjacent portions of the fixed rolls 11A and 11B and the floating rolls 12A and 12B, for example, the side surfaces of the floating rolls 12A and 12B. A driving convex portion 16 is formed.

Eccentric margins EA and EB are provided between the driving concave portion 15 and the driving convex portion 16 so that the floating rolls 12A and 12B can be eccentric. The sizes of the eccentric margins EA and EB are set to be approximately the same as the sizes of the clearances CA and CB between the roll shafts 7A and 7B and the floating rolls 12A and 12B.
In this embodiment, the driving concave portion 15 is formed on the fixed rolls 11A and 11B side and the driving convex portion 16 is formed on the floating rolls 12A and 12B side. Conversely, the driving concave portion 15 is driven on the fixed rolls 11A and 11B side. The convex portion 16 for driving may be formed, and the concave portion 15 for driving may be formed on the floating rolls 12A and 12B side.

  A pressing roll 19 is in contact with each of the floating rolls 12A and 12B. These pressing rolls 19 are pivotally supported by roll carriers 21A and 21B, respectively. And actuator 23A, 23B which presses floating roll 12A, 12B to fixed roll 11A, 11B side via roll carrier 21A, 21B and the press roll 19 is provided. As these actuators 23A and 23B, for example, a hydraulic cylinder, an air cylinder or the like is used.

  The actuators 23A and 23B press the floating rolls 12A and 12B to the opposing fixed rolls 11A and 11B with the pressing force F through the roll carriers 21A and 21B and the pressing roll 19, respectively. The pressing force F is set to a constant force that changes only the cross-sectional shape without impairing the thickness of the taper material M ′.

  As shown in FIGS. 3, 4, and 5, the combination rolls RA10 and RB10 are each bent with a corner portion CR that bends the taper material M ′ at a right angle in a cross-sectional view orthogonal to the longitudinal direction, for example. Mold into shape. For example, three corner portions CR are formed in the cross section of the taper material M ′, but only the central corner portion CR will be described here.

  As shown in FIG. 5 in an enlarged manner, for example, the outer peripheral portion of the floating roll 12A constituting the combination roll RA10 is provided with a convex forming portion FA that contacts the inside of the corner portion CR. The corner portion of the convex forming portion FA is R-chamfered. The corner radius of curvature is assumed to be r2.

  On the other hand, a concave forming portion FB that opposes the convex forming portion FA is formed at the step portion of the mating surface of the fixed roll 11B and the floating roll 12B that constitutes the combination roll RB10. The sandwiching angle of the concave forming portion FB is a right angle, but may be an R shape as long as it is smaller than the corner radius of curvature r2 or the radius of curvature of the outer periphery of the corner CR.

  As shown in FIG. 5, the corner radius of curvature r2 of the convex forming part FA of the combination roll RA10 (floating roll 12A) in this forming roll set RA10, RB10 is the preceding roll forming step (i) shown in FIG. Is set to a radius smaller than the corner radius of curvature r1 (indicated by a two-dot chain line in FIG. 5) of the forming roll group RA9, RB9. Further, the corner radius of curvature r2 is set equal to the target radius of curvature rt at the corner CR of the taper material M ′.

  Further, as shown in FIG. 5, a forming roll set that is a subsequent stage of this forming roll set RA10, RB10 (any one of RA11-13, RB11-13 shown in roll forming steps (k) to (m) shown in FIG. 1). ) Corner radius of curvature r3 is set to a value smaller than the corner radius of curvature r2. When the subsequent stage of the forming roll group RA10, RB10 is only one stage of the forming roll group RA11, RB11, the forming roll group RA11, RB11 is the final stage, and the corner radius of curvature is r3. As specific numerical values, for example, r1 is set to 5.00 mm, r2 (rt) is set to 4.82 mm, and r3 is set to 4.32 mm.

  According to this configuration, as indicated by a two-dot chain line in FIG. 5, the radius of curvature at the corner portion CR is reduced to 4.32 mm, which is r3, at the time of forming with the forming roll assembly having the corner portion radius of curvature r3. At this time, the outer peripheral line in the corner CR is expanded outward as indicated by the symbol ro.

  The roll forming apparatus 1 is configured as described above. When forming the taper material M ′, a combination roll RA10 including a fixed roll 11A concentrically provided on the roll shaft 7A and a floating roll 12A provided eccentrically and a roll shaft 7B provided concentrically. The taper material M ′ is fed between the fixed roll 11B and the combination roll RB10 including the floating roll 12B provided to be eccentric.

  Then, the actuators 23A and 23B press the floating rolls 12A and 12B to the opposing fixed rolls 11A and 11B via the pressing rolls 19, respectively. Thereby, the cross-sectional shape of the taper material M ′ is finally formed according to the shapes of the fixed rolls 11A and 11B and the floating rolls 12A and 12B. That is, the corner portion CR in the cross section of the taper material M ′ is curved and formed into the corner portion curvature radius r2, that is, the target curvature radius rt by the convex forming portion FA of the floating roll 12A.

  According to the roll forming apparatus 1 and the roll forming method, among the roll forming steps (a) to (m) shown in FIG. 1, one or a plurality of continuous roll forming steps including the final step (m) (k, l, m), a forming roll set (any one of RA11-13 and RB11-13) having a corner radius of curvature r3 smaller than the target radius of curvature rt (r2) at the corner CR of the taper material M ′. Thus, the corner portion CR is formed.

  Here, the bending angle of the taper material M ′ in the finishing process including the final stage (m) is substantially equal to the target bending angle. For example, when the corner portion CR is formed by a forming roll set having a corner radius of curvature equal to the target radius of curvature rt at the corner portion CR of the taper material M ′, the thickness of the taper material M ′ is thick. Since the spring back is small, the portion is formed at an angle substantially equal to the target angle. However, since the springback is large in the thin part, the bending angle after molding becomes larger than the target angle.

  In the present invention, the corner portion CR is formed by the forming roll groups RA11 to 13 and RB11 to 13 having the corner radius of curvature r3 smaller than the target radius of curvature rt. Spring back can be generated, and the bending angle after molding can be brought close to the target.

  In other words, as a countermeasure for springback when bending or bending metal materials, it is common to make the angle of the bending die smaller than the target angle and approximate the target shape when springback occurs. Is.

  However, since the angle of the spring back varies depending on the plate thickness, a metal material whose plate thickness varies along the longitudinal direction, such as the taper material M ′ in the present embodiment, has a degree of spring back that is long. Different for each place of direction. Therefore, in the method of making the bending angle smaller than the target angle as described above, only one of the thick part and the thin part can be accurately formed.

  When the springback is anticipated by reducing the bending R as in the present embodiment, the portion having a thick plate thickness (the portion having the plate thickness Tmax shown in FIG. 2B) where the generation amount of the springback is small and the shape is almost formed. ) Is molded at 90 °. In addition, the thin portion where the springback is likely to occur (the portion having the plate thickness Tmin shown in FIG. 2 (b)) is more effective than the thick portion because the effect of reducing the bending R is given. The angle can be closer to 90 °. Specifically, it can be within a range of about ± 3 ° with respect to a target forming angle of 90 °.

  For this reason, even in the taper material M ′ having a thin plate portion where springback is likely to occur, the bending angle at the corner portion CR becomes the target angle due to the occurrence of a large amount of springback at the corner portion CR. It can suppress that it expands more than (90 degree | times).

  In addition, since the corner portion CR of the taper material M ′ is bent in a plurality of stages, the influence of the springback can be reduced and the curvature radius accuracy of the corner portion CR can be increased. Therefore, the taper material M ′ whose thickness changes in the longitudinal direction can be roll-formed accurately and stably with a simple and inexpensive configuration.

  The plate thickness of the taper material M ′ changes in a taper shape along the longitudinal direction, but the floating rolls 12A and 12B are eccentric with respect to the roll shafts 7A and 7B in accordance with the change in the plate thickness. Thus, the difference in plate thickness is absorbed.

  At that time, the pressing force F of the actuators 23A and 23B is applied to the floating rolls 12A and 12B themselves via the pressing roll 19, and is not applied to the roll shafts 7A and 7B on which the floating rolls 12A and 12B are provided. For this reason, the taper material M ′ is predetermined while applying a constant pressing force F regardless of the eccentric position of the floating rolls 12A and 12B with respect to the roll shafts 7A and 7B, that is, regardless of the thickness of the taper material M ′. It can be formed into a shape.

  Therefore, the taper material M ′ whose plate thickness repeatedly changes in the longitudinal direction can be stably roll-formed with a very simple and inexpensive configuration.

  The pressing force F of the actuators 23A and 23B is set to a constant force that changes only the cross-sectional shape without impairing the thickness of the taper material M ′, so that the thickness of the taper material M ′ is reduced. The taper material M ′ is roll-formed into a predetermined cross-sectional shape while maintaining the originally planned plate thickness.

  As described above, according to the roll forming apparatus 1 according to the present embodiment, the taper material M ′ whose plate thickness repeatedly changes in the longitudinal direction can be roll-formed with high accuracy by a simple and inexpensive configuration.

  Further, in this roll forming apparatus 1, the floating rolls 12A and 12B are provided so as to be eccentric with respect to the roll shafts 7A and 7B, and these floating rolls 12A and 12B are connected to the actuators 23A and 23B via the pressing roll 19, respectively. It is the structure pressed by the fixed roll 11A, 11B side.

  For this reason, the taper material M ′ whose plate thickness repeatedly changes along the longitudinal direction can be molded while being pressed with a constant force without impairing the plate thickness. Thereby, the taper stringer TS etc. of an aircraft can be accurately shape | molded and manufactured.

[Second Embodiment]
FIG. 6 is a longitudinal sectional view showing a second embodiment of the present invention. This figure is the same as the configuration of FIG. 5 except that the corner radius of curvature r3, r4, r5 of the forming roll set that is the subsequent stage of the forming roll set RA10, RB10 is entered, so that each part is shown in FIG. The same reference numerals as in FIG.

  The corner radius of curvature r2 of the combination roll RA10 (floating roll 12A) is set equal to the target radius of curvature rt at the corner CR of the tapered material M '. And the corner part of the forming roll set (RA11, RB11 to RA13, RB13) shown in FIGS. 1 (k), (i), and (j) as the subsequent stage of this forming roll set (RA10 / RB10) The curvature radii r3, r4, and r5 are set to be smaller than the target curvature radius rt. As specific numerical values, for example, r1 is 5.00 mm, r2 (rt) is 4.82 mm, r3 is 4.62 mm, r4 is set to 4.52 mm, and r5 is set to 4.32 mm.

  That is, after the taper material M ′ is roll-formed by the forming roll group (RA10 / RB10) having the target curvature radius rt (r2), the taper material M ′ has the target curvature radii r3, r4, r5 smaller than the target curvature radius rt. The rolls (RA11, RB11 to RA13, RB13) are roll-formed a plurality of times, and at this time, the corner radiuses of curvature r3, r4, r5 become smaller from the front side to the rear side. At the time of forming with the final forming roll set RA13, RB13 having the corner radius of curvature r5, the outer peripheral line of the corner CR is expanded outward as indicated by the symbol ro.

  According to the roll forming apparatus 1 and the roll forming method, the corner CR of the taper material M ′ is smaller than the target curvature radius rt by the plurality of forming roll groups (RA11 / RB11 to RA13 / RB13). Since the elastic deformation is performed step by step to the radii r3, r4, and r5, it is possible to more effectively suppress the occurrence of springback in the corner portion CR.

  It should be noted that the present invention is not limited to the configuration of each of the embodiments described above, and can be appropriately modified or improved within the scope not departing from the gist of the present invention. The form is also included in the scope of the right of the present invention.

For example, in the above-described embodiment, the two roll shafts 7A and 7B are provided in a state in which the distance between the axes is fixed, but the distance between the axes may be variable.
Moreover, in the said embodiment, although the angle of the corner | angular part CR of taper raw material M 'is 90 degrees, it is not specifically limited to 90 degrees, Other angles may be sufficient.

Furthermore, the shape of the taper material M ′ and the shape of the taper stringer TS formed by the taper material M ′ are not limited to those of the above embodiment.
Furthermore, the present invention is not limited to the forming roll set in the finishing process (not limited to (j) to (m) in FIG. 1). For example, an intermediate stage for forming at the positions (g) to (i) in FIG. You may apply to a forming roll group, and you may make small the corner | angular part curvature radius in each forming roll group gradually.

DESCRIPTION OF SYMBOLS 1 Roll forming apparatus 7A, 7B Roll axis | shaft 11A, 11B One forming roll 12A, 12B The other forming roll 19 Press roll 23A, 23B Actuator CA, CB Clearance CR Corner part FA Convex formation part FB Concave formation part M ' Tapered material (metal material)
RA1 to RA13 / RB1 to RB13 Forming roll assembly a to m Roll forming step r1 Corner radius of curvature r2, r3 of the convex forming portion in the intermediate forming roll assembly Corner angle of the convex forming portion in the subsequent forming roll assembly Part radius of curvature rt Target radius of curvature at the corner of taper material (metal material)

Claims (6)

A plate-shaped metal material roll forming method in which the plate thickness varies along the longitudinal direction,
There is a multi-stage roll forming process in which the metal material is fed between a plurality of forming roll sets and is formed stepwise so that the cross-sectional shape perpendicular to the longitudinal direction has a curved corner portion. And
Among the plurality of roll forming steps, in one or a plurality of successive roll forming steps including the final step, the metal material has a corner radius of curvature smaller than a target radius of curvature at the corner of the metal material. A metal material roll forming method, wherein the corner portion is formed by a forming roll set.   The roll forming step of forming by the forming roll set having the corner portion radius of curvature smaller than the target curvature radius is performed a plurality of times, and at this time, the corner angle of the forming roll set from the front side to the back side. 2. The metal material roll forming method according to claim 1, wherein the radius of curvature of the metal is reduced. A roll forming apparatus that feeds a plate-like metal material between a plurality of forming roll sets, and forms the cross-sectional shape of the metal material into a predetermined shape step by step,
Among the plurality of forming roll sets, one or a plurality of continuous forming roll sets including the final forming roll set form a corner portion curved in a cross section perpendicular to the longitudinal direction of the metal material. A convex forming part that has a concave forming part facing the convex forming part,
The roll forming apparatus according to claim 1, wherein a corner radius of curvature of the convex forming portion is set to be smaller than a target radius of curvature at the corner of the metal material.   The forming roll set having the convex-shaped part having the corner radius of curvature smaller than the target radius of curvature has a plurality of stages, and the corner radius of curvature decreases from the front side to the rear side. The roll forming apparatus according to 3. One of the forming rolls in contact with one surface of the metal material is provided concentrically with respect to one roll axis,
The other forming roll that contacts the other surface of the metal material and faces the one forming roll is provided to be eccentric with respect to the other roll shaft via a clearance,
The roll forming according to claim 3 or 4, wherein the other forming roll provided in an eccentric manner is pressed against the one forming roll provided concentrically by a pressing roll contacting the outer peripheral portion thereof. apparatus.   The roll forming apparatus according to any one of claims 3 to 5, wherein the metal material is a taper material whose plate thickness repeatedly changes in the longitudinal direction.

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