JP2011098386A - Bending device and bending method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bending device which can improve workability for bending of a pipe material with a hollow cross section. <P>SOLUTION: The bending device includes a pair of wing-type dies 3 which are connected to be swingable through a pair of fulcra 2, a pair of chucks 4 for holding both ends of the pipe material W respectively, a supporting face 31 for supporting the pipe material W, a mounting face 32 for mounting the chuck 4, a back face 33 positioned opposite to the supporting face 31, a cushion pad 5 for urging the back face 33 toward the supporting face 31, a projected part 34 projecting from the back face 33 in the projection direction A toward the supporting face 31, a punch 6 for pressing the pipe material W in the direction B from the supporting face 31 toward the back face 33 selectively, and a constraining face 341 for imparting axial force to the pipe material W by constraining movement of the chucks 4 to the placing face 32 in the extending direction S of the pipe material W, when the punch 6 presses the pipe material W. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a bending apparatus and a bending method capable of obtaining higher workability when bending a pipe having a hollow cross section.

  In recent years, there has been an increasing demand for weight reduction of automobiles, which are sources of carbon dioxide, as an aid to prevent global warming. In particular, aluminum extruded alloy pipes are used for various parts such as bumper reinforcement. It has increased.

  Magnesium alloy extruded shapes and aluminum extruded alloy tubes are required for various parts mentioned above by bending cold or hot square or circular tubes that are generally extruded by hot working and have a hollow cross section. Bending into the desired shape. As an apparatus for bending a magnesium alloy extruded shape or an aluminum extruded alloy tube as described above, a bending apparatus as shown in Patent Document 1, for example, is used.

  In the bending apparatus shown in Patent Document 1, in order to prevent wrinkles and cross-sectional deformation due to compression inside the bending, the bending apparatus is equipped with a small and medium-sized insertion cylinder that pushes the core mold into the tube. For the purpose of imparting an axial tensile force to both ends of the tube material to be subjected to the above, a configuration comprising a gripping tool that grips both ends of the tube material and a stretch cylinder that presses the gripping tool outward in the axial direction is adopted. Yes.

JP-A-8-132142

  However, in such a bending apparatus shown in Patent Document 1, since it is necessary to use a core mold, the number of bending processes increases, and the structure of the structure includes a core mold insertion cylinder and a stretch cylinder. In addition to increasing the complexity, it becomes necessary to individually control the core insertion cylinder and the stretch cylinder. This also increases the number of man-hours, and it is not always easy to improve the workability of the bending process. For this reason, there existed a problem that the bending apparatus which can improve the workability in bending the pipe material which has a hollow cross section more appropriately could not be provided.

  In view of the above problems, an object of the present invention is to provide a bending apparatus and a bending method capable of improving workability when bending a pipe having a hollow cross section.

In order to solve the above problem, the bending apparatus according to the present invention is:
A pair of bases;
A pair of winged dies that are slidably coupled via a pair of fulcrums respectively corresponding to the pair of bases;
A pair of gripping portions for gripping both ends of the pipe material,
A support surface that forms part of the wing die and supports the tube;
A mounting surface on which the gripping portion is mounted as a part of the wing die;
A back surface that forms part of the wing die and is located opposite the support surface;
A biasing portion that biases the back surface in a direction from the back surface toward the support surface;
A protruding portion that forms a part of the wing die and protrudes in a protruding direction from the back surface toward the support surface;
A punch that selectively presses the tube material in a direction from the support surface toward the back surface;
Constraint that forms a part of the projecting portion and restricts relative movement of the gripping portion with respect to the placement surface in the extending direction of the tube material when the punch presses the tube material and applies an axial force to the tube material Surface,
It is characterized by including.

  The punch is operated by a crank mechanism, for example, in a direction perpendicular to a straight line connecting the pair of fulcrum and passing through a midpoint of the pair of fulcrum as viewed from the fulcrum direction. The tube material is selectively pressed. Further, the gripping part is a so-called chuck that grips both ends of the pipe material, and in order to ensure contact with the restraint surface as compared with a round chuck used in a normal tensile test, It is comprised in a rectangular parallelepiped shape so that the to-be-restricted surface contacted with the said restraint surface may be included.

  According to the bending apparatus, the punch is supported in a state where the tube is supported by the support surface, and the gripping portions that grip the both end portions that are free ends of the tube are placed on the placement surface. When the tube material is pressed by displacing the tube material and the pair of wing-type dies in a forward direction, the gripping portion is bent when the tube material is bent between the punch and the wing-type die. Can be restrained by the restraining surface from being moved relative to the placement surface in the extending direction.

  Here, when the bending device is a so-called upper fulcrum type in which the fulcrum is located on the protruding direction side with respect to the support surface, the punch side of the pair of wing-type dies is free on the punch side. The ends are displaced in directions away from each other when viewed from the fulcrum direction while swinging and displacing in the circumferential direction around the fulcrum. Therefore, a so-called tensile bending process is performed in which the pipe material is bent while being pulled in the extending direction.

  About the said pipe material, the side which contacts the said punch will be compressed by the bending deformation accompanying the press of the said punch, and the side which contacts the said support surface will be pulled. For this reason, when the tube material is a magnesium alloy extruded shape and has a characteristic that the deformation resistance on the compression side is smaller than that on the tension side, the fracture occurs even if the thickness increase on the compression side occurs. In addition, there is a concern that wrinkles are generated due to large deformation in a bellows shape.

  When there is no restraint by the restraint surface, the gripping portion tends to move relative to the punch side, that is, the midpoint side of the pair of support points in the extending direction with respect to the placement surface as viewed from the fulcrum direction. However, since the restraining surface restrains and prevents this relative movement, a tensile force acts on the tube material, and the compressing force on the compression side or the compressive strain due to the compressing force is partially offset and canceled out. And the occurrence of wrinkles as described above can be prevented.

  Here, when the bending device is a so-called lower fulcrum type in which the fulcrum is located on the side opposite to the projecting direction from the support surface, the punch side of the pair of wing dies is pressed by the punch. The free ends of the two are displaced in a direction approaching each other when viewed from the fulcrum direction while swinging and displacing in the circumferential direction around the fulcrum. Therefore, a so-called compression bending process is performed in which the pipe material is bent while being compressed in the extending direction.

  About the said pipe material, the side which contacts the said punch will be compressed by the bending deformation accompanying the press of the said punch, and the side which contacts the said support surface will be pulled. For this reason, when the tube material is an aluminum extruded alloy tube material and has a characteristic that the ductility is low but the strength is high, there is a concern that cracks and fractures including microcracks may occur on the tensile side. It will be.

  When there is no restraint by the restraint surface, the gripping portion tends to move relatively to the punch side, that is, the side away from the midpoint of the pair of support points with respect to the placement surface as viewed from the fulcrum direction. In order to restrain and prevent the relative movement of the restraint surface, it is assumed that a compressive force acts on the pipe material, and cancels and partially cancels the tensile force on the tension side or the tensile strain due to the tensile force, It is possible to prevent the above-described cracks and breaks from occurring.

  As described above, in the bending apparatus, in order to prevent cracks or breaks on the compression side of the pipe material or on the tensile side, either the tensile force or the compression force that needs to be applied to the pipe material is used. The certain axial force can be generated as a passive force accompanying contact and interference between the gripping portion and the restraining surface of the protruding portion caused by the pressing of the punch.

  For this reason, the core type used in the prior art, the cylinder in which the core type is inserted into the hollow cross section of the tubular material, and the tensile force for canceling the compressive force on the compression side of the tubular material are generated. And the cylinder for generating the compressive force for canceling the tensile force on the pulling side of the pipe material are unnecessary, simplifying the configuration of the bending apparatus itself, The process itself can be simplified and the workability of bending can be improved.

Here, in the bending apparatus,
It is preferable that the length of the constraining surface in the protruding direction is shorter than the length of the grip portion by a predetermined length.

  According to the bending apparatus, when the pipe is bent by pressing the punch, and when the punch is moved backward in a direction away from the wing die, the gripping part, the restraining surface, Can be separated smoothly.

In the bending apparatus,
It is preferable that an adjustment unit for adjusting the distance of the fulcrum with respect to the support surface in the protruding direction is included.

  According to the bending apparatus, it is possible to relatively easily increase the degree of freedom of the relative movement restriction mode by the restriction surface.

Furthermore, it is preferable that the distance is adjusted according to the axial force in the bending apparatus.

  According to the bending apparatus, it is possible to appropriately adjust the distance according to a desired design value of the axial force.

Here, in the bending apparatus,
It is preferable that the axial force is within a permissible value for strain generated in the pipe material in the bending process.

  According to the bending apparatus, the distance can be adjusted as appropriate after determining the design value of the axial force so that the strain falls within the allowable value.

In addition, as one aspect of the bending apparatus,
The fulcrum is positioned on the projecting direction side with respect to the support surface, the restraint surface is positioned on the punch side with respect to the gripping portion, and the axial force is used as a tensile force against the tube material, and the tensile force is The larger the distance, the longer the distance can be selected.

  The bending apparatus according to this aspect can select a preferable aspect of the so-called upper fulcrum type and can more accurately adjust a desired design value of the tensile force based on the distance. can do.

Alternatively, as one aspect of the bending apparatus,
The fulcrum is positioned on the opposite side of the projecting direction from the support surface, the restraint surface is positioned on the opposite side of the punch from the gripping portion, and the axial force is used as a compressive force for the tube material. At the same time, it is possible to select to increase the distance as the compression force is increased.

  The bending apparatus according to this aspect can select a preferable aspect in a so-called lower fulcrum type and can more accurately adjust a desired design value of the compression force based on the distance. can do.

Moreover, in order to solve the above-mentioned problem, the bending method according to the present invention is:
A bending method for the tube material using the bending device according to claim 1, wherein the tube material is pressed by the punch, and the gripping portion is constrained by the constraining surface to the shaft. A constraining step of applying a force to the tube.

  According to the bending method, the constraining step can be performed passively and simultaneously with the pressing step, and the occurrence of wrinkles or cracks in the bending of the pipe material is more effective while improving the workability of bending. Can be prevented.

Furthermore, in the bending method,
In the case where the pipe material has an uneven thickness that varies depending on the circumferential position in a cross section perpendicular to the extending direction, the thick portion having the thick thickness may be positioned on the opposite side of the support surface.

  According to the bending method, generation of wrinkles on the compression side of the pipe material can be prevented particularly when the pipe material is a magnesium alloy extruded shape.

  According to the present invention, a pipe having a hollow cross section can be bent while maintaining higher workability.

It is a schematic diagram which shows one Embodiment (upper fulcrum type) of the bending apparatus which concerns on this invention. It is a schematic diagram which shows the form of the punch which one Embodiment of the bending apparatus which concerns on this invention contains. It is a schematic diagram which shows the form of the punch corresponding to the wing type | mold die which one Embodiment of the bending apparatus which concerns on this invention contains. It is a schematic diagram which shows the form of operation | movement of the wing type | mold die and chuck | zipper which one Embodiment of the bending apparatus which concerns on this invention contains. It is a schematic diagram which shows the form of the chuck | zipper which one Embodiment of the bending apparatus which concerns on this invention contains. It is a schematic diagram which shows the form of the holding tool used in the chuck | zipper which one Embodiment of the bending apparatus which concerns on this invention contains. It is a schematic diagram which shows the form of the adjustment part which adjusts the position of the fulcrum with respect to the support surface of the wing type | mold die which one Embodiment of the bending apparatus which concerns on this invention contains. It is a schematic diagram which shows the form of the adjustment part which adjusts the position of the fulcrum with respect to the support surface of the wing type | mold die which one Embodiment of the bending apparatus which concerns on this invention contains. It is a schematic diagram which shows the form in the state which has a punch in a bottom dead center after completion | finish of the bending process of the wing type | mold die and chuck | zipper which one Embodiment of the bending apparatus which concerns on this invention contains. It is a schematic diagram which shows the form in the state after the punch moved toward the top dead center from the bottom dead center after the bending process of the wing type die and chuck included in the embodiment of the bending apparatus according to the present invention. It is a schematic diagram which shows other embodiment (lower fulcrum type | mold) of the bending apparatus which concerns on this invention. It is a schematic diagram which shows the form in the state which has a punch in a bottom dead center after completion | finish of the bending process of the wing type | mold and chuck | zipper which other embodiment of the bending apparatus which concerns on this invention includes. It is a schematic diagram which shows the form in the state after a punch moves toward the top dead center from the bottom dead center after the bending process of the wing type die and chuck which other embodiment of the bending apparatus which concerns on this invention includes.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the accompanying drawings.

  In the first embodiment, the bending apparatus 1 includes a pair of wing type die support portions 7 (base portions) and a pair of wing type die support portions 7, which show only one of the pair of symmetrically positioned in FIG. 4. A pair of wing-type dies 3 that are swingably coupled via a corresponding pair of fulcrums 2 and a pair of chucks 4 (gripping portions) that respectively grip both ends of the pipe W are configured. A flat portion 71 is provided on the rear side in FIG. 4 of the projecting portion including the fulcrum 2 of the wing die support portion 7, and the swing range of the wing die 3 is determined from the plane including the pair of flat portions 71. The stopper which restrict | limits only to the advancing direction B side shown in FIG. 1 is comprised.

  Further, the bending apparatus 1 includes a support surface 31 that forms a part of the wing die 3 and supports the pipe W, and a chuck 4 that forms a part of the wing die 3 as shown in FIGS. 4 and 1. A rear surface 33 that is a part of the wing die 3 and is located on the opposite side of the support surface 31, and a cushion that biases the rear surface 33 in the direction from the rear surface 33 toward the support surface 31. The pad 5 (the urging portion) and a protruding portion 34 that forms a part of the wing die 3 and protrudes in a protruding shape A from the back surface 33 toward the support surface 31 are included.

  In addition, the bending apparatus 1 includes the punch 6 that selectively presses the tube material W in the forward direction B from the support surface 31 toward the back surface 33, and the extension of the tube material W of the chuck 4 as a part of the protrusion 34. A restraint surface 341 that restrains the relative movement with respect to the mounting surface 32 in the direction S when the punch 6 presses the tube material W and applies an axial force to the tube material W.

  Furthermore, as shown in FIG. 4, a pair of wing side flanges 35 are provided on both sides of the support surface 31 of the wing die 3 so as to protrude in the protruding direction A from the support surface 31.

  1 and 2, a straight line C is perpendicular to a straight line connecting the pair of fulcrums 2 when viewed from the direction of the fulcrum 2 showing only one of the pair of inner right sides in FIG. It is a straight line passing through the midpoint of fulcrum 2. The straight line C coincides with the center of the punch 6 in the left-right direction in FIGS. As shown in FIGS. 1 and 2, the punch 6 is formed in a tongue-like shape that is curved with a predetermined radius in a convex shape with respect to the forward direction B.

  The punch 6 is operated so as to be movable forward and backward in the direction of the straight line C by a crank mechanism (not shown) driven by a motor, for example. FIG. 3 is a right side view of FIG. 2. As shown in FIG. 3, the left side of the punch 6 has a front punch side flange 61 disposed on the left side, and the right side of the punch 6 has a rear punch side. A flange 62 is disposed, and the punch-side flange 62 is set to have a smaller vertical dimension in FIG. 3 than the punch-side flange 61. The punch-side flange 61 and the punch-side flange 62 are aligned with the lower ends in FIG. In a state of being sandwiched, the fixing bolt 63 is integrally configured.

  2 and 3, the base plate BA of the movable portion of the crank mechanism is located on the upper side. As shown in FIG. 3, the base plate BA includes a punch holder H that protrudes downward. The punch 6, the punch side flange 61, and the punch side flange 62 that are integrated as described above are fixed to the left side surface of the punch holder H shown in FIG.

  The punch 6 selectively presses the tube material W supported by the support surface 31 of the wing die 3 based on the operation of the crank mechanism. Here, the wing side flanges 35 shown in FIGS. 4 and 1 located on both sides of the support surface 31 of the wing die 3 regulate the displacement of the tube material W to the side of the support surface 31, and the punch side flange 61. And 62 guide surfaces.

  Further, the chuck 4 constituting the gripping portion of the wing die 3 is different in form from the round chuck used in the normal tensile test, and in order to ensure the contact with the restraining surface 341, It is configured in a rectangular parallelepiped shape as shown in FIG. 5 so as to include a constrained surface 41 that comes into contact with the constraining surface 341 in the same plane.

  As shown in FIG. 5 (a), the chuck 4 is configured by chamfering each corner of a rectangular parallelepiped shape that is flat in the paper surface direction in FIG. 5 (a), and in FIG. 5 (a) and FIG. 5 (a). A constrained surface 41 is configured as shown in FIG. As shown in FIG. 5 (a), a trapezoidal columnar concave portion 42 having a trapezoidal bottom surface whose left bottom is longer than the right bottom from the front side in the paper direction to the back side is configured by cutting. As shown in FIG. 5C, which is a right view in FIG. 5A, the recess 42 has a shape that opens in the extending direction S of the tube material W (not shown) toward the facing surface of the constrained surface 41. Eggplant. Further, as shown in FIG. 5A, a bolt insertion hole 43 is formed from the constrained surface 41 toward the recess 42.

  In the recess 42 shown in FIG. 5 (a), before one of the both ends of the above-described tube material W is inserted and stored from the front side in the middle of FIG. 5 (a), the direction of the middle paper in FIG. A pair of wedge-shaped spaces formed in the gap between the outside of the space in which the tubular material W that is a square tube or a circular tube as viewed from the front side and the trapezoidal columnar concave portion 42 are formed as shown in FIG. The grippers 44 are arranged and set in advance so as to correspond to the pair of wedge-shaped spaces, respectively.

  The direction shown in FIG. 6 (b) coincides with the paper surface direction in FIG. 5 (a). As shown in FIG. 6 (b), the gripping tool 44 has an extension of the pipe W on the pipe W side (not shown). A file surface 441 parallel to the direction S is configured, and an opposite side to the tube material W is parallel to the side wall of the trapezoidal columnar recess 42 of the recess 42 and an inclined surface 422 that is inclined with respect to the extending direction S of the tube material W is configured. To do. The file surface 441 of the gripping tool 44 indicated by A in FIG. 6B has a relatively rough file-like surface as shown in FIG. 6D, for example.

  In the state where the pair of grips 44 are set in the pair of wedge-shaped spaces inside the recess 42 shown in FIG. By screwing the fastening bolt into the bolt insertion hole 43 and pressing the end of the fastening bolt against the end of the pipe W through a jig (not shown), the grip 44 positioned on both sides of the pipe W is a file surface. Fastening is performed by the biting action of 441, and the gripping tool 44 and the side surface of the recess 42 are fastened by the taper effect of the inclined surface 441, and the chuck 4 grips the end of the tube material W.

  The tube material W whose both ends are gripped by the chuck 4 is supported on the support surfaces 31 of both the pair of wing dies 3 in the initial state, and the chuck 4 has the side having the recess 42 directed toward the placement surface 32. It is mounted on the mounting surface 32.

  In the bending apparatus 1 according to the first embodiment, the length L341 of the restraining surface 341 in the protruding direction A shown in FIG. 1 is made shorter than the length L4 of the chuck 4 by a predetermined length.

  Further, in the bending apparatus 1 of the first embodiment, the distance la ″ ′ from the center of the fulcrum 2 with respect to the support surface 31 in the protruding direction A shown in FIG. 1 is adjusted, for example, as shown in FIG. 1, the fulcrum 2 is constituted by a cylindrical rod-shaped shaft as shown in Fig. 1, but the adjustment unit 8 swings the shaft constituting the fulcrum 2 as shown in Fig. 7. The fulcrum support part 82 which has the hole part 81 supported so that it can move freely, and the fixing | fixed part 83 which fixes the fulcrum support part 82 to the wing type | mold die 3 are comprised.

  The fulcrum support portion 82 shown in the DD cross section of the wing die 3 shown in FIG. 7 has a hole portion 81 at the lower end portion of the fulcrum support portion 82. As shown in FIG. The distance la ″ with respect to the center of the fulcrum 2 with respect to the support surface 31 is adjusted by appropriately replacing the upper end with one having the hole 81.

  That is, as for the fulcrum support portion 82, a plurality of types of holes 81 provided in arbitrary multiple stages between the lower end portion and the upper end portion are manufactured in advance, and the distance la "needs to be changed. In this case, the distance la "is adjusted by exchanging with the fulcrum support part 82 corresponding to the changed distance la".

  In this case, in the bending apparatus 1 according to the first embodiment, the distance la ″ is adjusted according to the axial force applied to the tube W by the restraint surface 341 restraining the restrained surface 41 of the chuck 4. It is assumed that the axial force falls within the allowable value for the strain generated in the pipe W during bending.

  In addition, generally the extruded shape material which comprises the pipe material W may have the uneven thickness from which thickness differs in the circumferential direction position, and this uneven thickness can also be provided intentionally. When bending is performed on the tube material W, even if there is no uneven thickness in the initial state before bending, a thickening occurs on the inner side of the bending, that is, on the compression side, and the neutral surface is generally the compression side. Will be moved to.

  Here, if the pipe W is set and bent so that the tension side is thick and the compression side is thin, the neutral surface does not necessarily move to the compression side due to the difference in thickness at the time of setting. No longer limited. In particular, when the tube material W is constituted by a magnesium alloy extruded profile, the average deformation resistance is smaller on the compression side than on the tension side, the compression side is greatly deformed, and the neutral surface tends to move to the tension side. .

  Therefore, when the tube material W is a magnesium alloy extruded shape, when bending is performed, the thick wall portion is disposed on the compression side, the thin wall portion is disposed on the tension side, and there is uneven thickness. Although there is room for selecting according to the individual material to perform bending while applying tensile force to a non-pipe material W, from an industrial standpoint, the last method using a pipe material W having no uneven thickness is Safe and easy.

  In addition, in the bending apparatus 1 of the first embodiment, the fulcrum 2 is positioned on the protruding direction A side with respect to the support surface 31, and the restraining surface 341 is positioned on the punch 6 side with respect to the chuck 4, so that the axial force is increased. While the tensile force is applied to the pipe W, the distance la "is increased as the tensile force is increased.

  According to the bending apparatus 1 of the first embodiment, the tube material W is supported by the support surface 31, and the chuck 4 that grips both ends of the tube material W is placed on the placement surface 32. When the punch 6 is displaced in the forward direction B shown in FIG. 1 approaching the tube material W based on the operation of the crank mechanism and the tube material W is pressed, the tube material W is paired with the punch 6 and a pair of left and right wings. When the chuck 4 is bent with the die 3, the chuck 4 moves relative to the mounting surface 32 in the extending direction S in the direction close to the punch 6 with respect to the restrained surface 41 of the restraint surface 341. It can be restrained and blocked based on the contact.

  Since the bending device 1 according to the first embodiment is an upper fulcrum type in which the fulcrum 2 is located on the protruding direction A side with respect to the support surface 31, the punch 6 is free on the punch 6 side of the pair of wing dies 3. The ends are oscillated and displaced in the circumferential direction around the fulcrum 2 and are displaced in directions away from each other when viewed from the fulcrum 2 direction, so that the pipe W is bent while being pulled in the extending direction S.

  The tube material W is compressed by the bending deformation accompanying the pressing of the punch 6, the side contacting the punch 6 is compressed, the side contacting the support surface 31 is pulled, and the tube material W is a magnesium alloy extruded shape. When the resistance is smaller than that on the tension side, there is a concern that even if the compression-side increase in thickness occurs, breakage may occur, or wrinkles may occur due to large deformation in a bellows shape. It becomes a problem.

  As shown in the bending apparatus 1 of the first embodiment, when the relative movement with respect to the mounting surface 32 in the extending direction S of the chuck 4 is not restrained by the restraining surface 341 as shown in FIG. As viewed from two directions, the chuck 4 exhibits a behavior of moving relative to the punch 6 side, that is, the straight line C side in the extending direction S with respect to the mounting surface 32, but the restraining surface 341 restrains and prevents this relative movement. A tensile force acts on the pipe W, and cancels and reduces a part of the compressive force on the surface side that is in contact with the punch 6 of the pipe W, that is, the compression side, and the above-described fracture occurs on the compression side. Can be prevented.

  Furthermore, in the bending apparatus 1 according to the first embodiment, for the purpose of preventing wrinkles on the compression side of the tube material W, a tensile force necessary to be applied to the tube material W is applied to the chuck 4 by pressing the punch 6. It can be generated as a passive force generated when the constrained surface 41 and the constraining surface 341 of the protrusion 34 come into contact with each other and interfere with each other.

  For this reason, the core type as used in Patent Document 1 shown in the prior art, the cylinder in which the core type is inserted into the hollow cross section of the tube material W, and the compression force on the compression side of the tube material W are offset. A cylinder for generating a pulling force is unnecessary, and in the bending apparatus 1, a power mechanism other than a crank mechanism that moves the punch 6 in the advancing and retracting direction can be eliminated. While simplifying, the process of a bending process and the control accompanying a process can be simplified, and the workability of a bending process can be improved.

  Further, in the bending apparatus 1 of the first embodiment, the length L341 of the restraining surface 341 in the protruding direction A shown in FIG. 1 is shorter than the length L4 of the chuck 4 by a predetermined length. As shown in FIG. 9, after the bending of the tube material W by pressing the punch 6 is finished, as shown in FIG. 10, when the punch 6 is displaced in the retracting direction away from the wing die 3, the bending is performed. The processed pipe W is attached to the pressing surface of the punch 6 due to the compressive force remaining inside due to bending deformation, is retreated with the punch 6, and reduces the frictional force generated with the restraining surface 341. The chuck 4 and the restraining surface 341 are smoothly separated from each other so that the lower end of the surface having the length L4 of the chuck 4 does not come into contact with the upper end of the restraining surface 341. Formula die 3 in the initial state It can be attributed.

  Further, in the bending apparatus 1 according to the first embodiment, the adjusting unit 8 as shown in FIG. 7 or 8 for adjusting the distance la ″ of the fulcrum 2 with respect to the support surface 31 in the protruding direction A shown in FIG. Therefore, it is possible to relatively easily increase the degree of freedom of the restraining mode of relative movement in the extending direction S with respect to the mounting surface 32 of the chuck 4 by the restraining surface 341.

  Furthermore, in the bending apparatus 1 according to the first embodiment, the distance la ″ is adjusted according to the axial force applied to the pipe W by the restraint surface 341 restraining the chuck 4. The distance la ″ can be appropriately adjusted according to the desired design value.

  Further, in the bending apparatus 1 of the first embodiment, the axial force generated by the restraining surface 341 is intended to keep the distortion generated inside the pipe material W during the bending process within an allowable value. The distance la ″ can be adjusted as appropriate after determining the design value of the axial force generated by the constraining surface 341 so that the distortion generated in is kept within an allowable value.

  In addition, in the bending apparatus 1 of the first embodiment, the fulcrum 2 is positioned on the protruding direction A side with respect to the support surface 31, and the restraining surface 341 is positioned on the punch 6 side with respect to the chuck 4, so that the axial force is increased. Since the tensile force on the pipe W can be selected and the distance la ″ can be increased as the tensile force is increased, it is possible to select a preferable mode in the bending apparatus 1 using the upper fulcrum type wing die 3. In addition, the desired design value of the tensile force to be applied can be adjusted more precisely based on the distance la ″.

  Moreover, in the bending process by the bending apparatus 1 of the first embodiment, the bending method according to the present invention is executed simultaneously. That is, the pressing step of pressing the tube material W by the punch 6 and the restraining step of restraining the chuck 4 by the restraining surface 341 and applying the axial force to the tube material W, which are included in the method of bending a tube material of the present invention, are automatically performed. To be executed.

  According to the bending method of the present invention executed in the first embodiment, the constraining step can be performed passively and simultaneously with the pressing step, and the bending property of the pipe W is improved while improving the workability of the bending process. Generation | occurrence | production of soot can be prevented more effectively.

  Furthermore, in the bending method executed in the first embodiment, when the pipe material W has an uneven thickness that varies depending on the circumferential position in a cross section perpendicular to the extending direction S, the thick wall is thick. It is preferable to position the portion on the opposite side of the support surface 31. According to this bending method, generation of wrinkles on the compression side of the tube material W can be prevented particularly when the tube material W is a magnesium alloy extruded shape.

  In the first embodiment described above, as shown in FIG. 1, the bending apparatus 1 is used as the upper fulcrum type, and the restraining surface 341 is positioned on the straight line C side of the chuck 4, but the bending apparatus 1 is used as the lower fulcrum type. As an alternative, the restraining surface 341 can be positioned on the opposite side of the chuck 4 from the straight line C. The second embodiment will be described below.

  As shown in FIG. 11, the bending apparatus 1 according to the second embodiment is a lower fulcrum type in which the fulcrum 2 is located on the forward direction B side with respect to the support surface 31 of the wing die 3, and the protrusion 34 is a wing type. The surface of the mounting surface 32 of the die 3 that is located farther from the straight line C than the portion on which the chuck 4 is mounted, and the surface of the protrusion 34 that faces the straight line C constitutes a restraining surface 341, The point which the surface on the opposite side to the recessed part 42 which is the part which hold | grips the pipe material W comprises the to-be-restricted surface 41 differs from Example 1. FIG.

  As described above, in the bending apparatus 1 according to the second embodiment, as shown in FIG. 11, the fulcrum 2 is positioned on the side opposite to the protruding direction A from the support surface 31, and the restraint surface 341 is punched more than the chuck 4. 6, the axial force is set as a compressive force on the pipe W, and the distance la "is increased as the compressive force is increased.

  In the bending apparatus 1 according to the second embodiment, the length L341 of the restraining surface 341 in the projecting direction A shown in FIG. 11 is made shorter than the length L4 of the chuck 4 by a predetermined length.

  The bending apparatus 1 according to the second embodiment can select a preferable mode in the lower fulcrum type, and can make the desired design value of the compression force more accurately adjustable based on the distance la ″. Since the bending apparatus 1 of Example 2 is a lower fulcrum type, the free ends on the punch 6 side of the pair of wing dies 3 are oscillated and displaced in the circumferential direction around the respective fulcrums 2 by the pressing of the punch 6. When the tube W is displaced in the extending direction S while being displaced in a direction approaching each other when viewed from the fulcrum 2 direction, compression bending is performed.

  As for the pipe material W, the side in contact with the punch 6 is compressed and the side in contact with the support surface 31 is pulled by the bending deformation accompanying the pressing of the punch 6, and the pipe W is particularly an aluminum extruded alloy pipe material, and is ductile. Is low but has high strength, the problem is that cracks, microscopic cracks and fractures occur on the tension side.

  When there is no restraint by the restraint surface 341, the chuck 4 moves relative to the mounting surface 32 shown in FIG. 11 toward the punch 6 side, that is, the side away from the midpoint of the pair of support points 2 when viewed from the fulcrum 2 direction. However, since the restraining surface 341 restrains and prevents the relative movement in the separated direction, a compressive force acts on the pipe W, and the tensile force on the pulling side is partially offset and canceled and reduced. It is possible to prevent the occurrence of cracks, microscopic cracks and breaks.

  Further, in the bending apparatus 1 according to the second embodiment, the length L341 of the restraining surface 341 in the protruding direction A shown in FIG. 11 is shorter than the length L4 of the chuck 4 by a predetermined length. 12, after the bending process of the tube material W by the pressing of the punch 6 is finished, as shown in FIG. 13, the bending is performed when the punch 6 is displaced in the retracting direction away from the wing die 3. The processed tube W is attached to the pressing surface of the punch 6 due to the compressive force remaining inside due to bending deformation and is moved backward together with the punch 6, and between the constrained surface 41 of the chuck 4 and the constraining surface 341. The wing die 3 can be returned to the initial state in accordance with the backward displacement of the punch 6 by smoothly separating the chuck 4 and the restraining surface 341 by reducing the frictional force generated in the punch 6.

  Also in the bending apparatus 1 according to the second embodiment, the chuck caused by the pressing of the punch 6 has a compressive force necessary to be applied to the pipe W in order to prevent cracking, microscopic cracking and breakage of the pipe W. 4 can be generated as a passive force accompanying contact and interference with the restraint surface 341 of the projecting portion 34, simplifying the configuration of the bending apparatus 1 itself, simplifying the bending process itself, and bending The workability of processing can be improved.

  Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and various modifications and substitutions are made to the above-described embodiments without departing from the scope of the present invention. be able to.

  The present invention provides a bending apparatus and a bending method for bending a pipe having a hollow cross section, can improve the workability in bending, and can configure the bending apparatus with a simpler mechanism. Therefore, the present invention is useful for manufacturing parts constituted by bending a tubular material having a hollow cross section such as magnesium alloy extruded shapes such as various parts for automobiles and handrails for chairs and aluminum extruded alloy tubular materials.

DESCRIPTION OF SYMBOLS 1 Bending apparatus 2 Supporting point 3 Wing type die W Pipe material S Extension direction A Protrusion direction B Forward direction 31 Support surface 32 Mounting surface 33 Back surface 34 Protrusion part 341 Restriction surface 35 Wing side flange 4 Chuck (gripping part)
41 Constrained surface 42 Concave portion 43 Bolt insertion hole 44 Grasp 5 Cushion pad (biasing portion)
6 Punch 61 Punch side flange (Front side: Large)
62 Punch side flange (back side: small)
63 Fixing bolt 64 Mounting bolt 65 Key H Punch holder BA Base plate 7 Wing type die support (base)
71 Plane portion 8 Adjustment portion 81 Hole portion 82 Support point support portion 83 Fixing portion

Claims (9)

A pair of bases;
A pair of winged dies that are slidably coupled via a pair of fulcrums respectively corresponding to the pair of bases;
A pair of gripping portions for gripping both ends of the pipe material,
A support surface that forms part of the wing die and supports the tube;
A mounting surface on which the gripping portion is mounted as a part of the wing die;
A back surface that forms part of the wing die and is located opposite the support surface;
A biasing portion that biases the back surface in a direction from the back surface toward the support surface;
A protruding portion that forms a part of the wing die and protrudes in a protruding direction from the back surface toward the support surface;
A punch that selectively presses the tube material in a direction from the support surface toward the back surface;
Constraint that forms a part of the projecting portion and restricts relative movement of the gripping portion with respect to the placement surface in the extending direction of the tube material when the punch presses the tube material and applies an axial force to the tube material Surface,
A bending apparatus comprising:   2. The bending apparatus according to claim 1, wherein the length of the constraining surface in the projecting direction is shorter than the length of the grip portion by a predetermined length.   The bending apparatus according to claim 1, further comprising an adjustment unit that adjusts a distance of the fulcrum with respect to the support surface in the protruding direction.   The bending apparatus according to claim 3, wherein the distance is adjusted according to the axial force.   The bending apparatus according to claim 4, wherein the axial force is configured to keep a strain generated in the pipe material in the bending process within an allowable value.   The fulcrum is positioned on the projecting direction side with respect to the support surface, the restraint surface is positioned on the punch side with respect to the gripping portion, and the axial force is used as a tensile force against the tube material, and the tensile force is The bending apparatus according to claim 5, wherein the distance is increased as the distance increases.   The fulcrum is positioned on the opposite side of the projecting direction from the support surface, the restraint surface is positioned on the opposite side of the punch from the gripping portion, and the axial force is used as a compressive force for the tube material. The bending apparatus according to claim 6, wherein the distance is increased as the compressive force is increased.   A bending method for the tube material using the bending device according to claim 1, wherein the tube material is pressed by the punch, and the gripping portion is constrained by the constraining surface to the shaft. And a constraining step of applying a force to the pipe material.   The thick portion having the thick thickness is positioned on the opposite side of the support surface when the pipe material has an uneven thickness that varies depending on a circumferential position in a cross section perpendicular to the extending direction. The bending method according to 8.

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