JP2007307615A - Apparatus and method of press-bending tubular material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a new apparatus and method of bending a tubular material by which the compatibility of three properties of the bending work of a large bend radius without requiring large-scale equipment and die, a bending work by which wrinkles and buckling can not be generated inside the bending and a bending work having high productivity is made possible. <P>SOLUTION: This apparatus is a press-bending apparatus for performing the three-point bending of the tubular material with a punch 12 and a set of rolls 13, 13, the punch 12 has a groove 12a having width larger than the width of a round tube 11 and the set of the rolls 13, 13 are supported with stands 14. The rolls 13, 13 are freely movable on the stands 14 in the direction away from each other in the state where they are brought into contact with the punch 12. The stands 14 have a void 14a for making the punch 12 which is lowered during the bending work of the round tube 11 and the round tube 11 which is bent with the lowering freely movable. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a pipe bending apparatus and a bending method for manufacturing automobile parts, building material parts, furniture parts, and the like.

  In recent years, in the fields of automobile parts, building material parts, furniture parts, etc., it has been required to reduce the weight as much as possible while securing rigidity, but it is effective to make the material hollow as one of the means It is. On the other hand, these parts are also increasingly being bent due to needs such as small space arrangement, designability, and integration of multiple parts.

  There are a great many types of pipe bending methods. Non-Patent Document 1 includes several examples of bending (see FIG. 1), press bending (see FIG. 2), and pressing bending (see FIG. 3).

  Among them, the bending is the most widely used method. As an advantage, since the pipe material is restrained by a wiper die, a mandrel, a pressure die or the like, wrinkles or buckling hardly occurs inside the bending, and bending with a small bending radius is possible. However, in other words, there is a disadvantage that many molds are required when performing one kind of bending. Further, although it is good at bending with a small bending radius, a large rotary bending die is required when bending with a large bending radius, and the apparatus itself needs to be enlarged. In order to avoid an increase in the size of the device, by repeating the bending of a small bending radius and a linear shape, it is sometimes performed to approximate the entire bending to a bending of a large bending radius. Cycle time is long and productivity is not good. In addition, there is a drawback that the bending shape is only an arc, and in principle, only bending with one kind of bending radius can be processed.

  On the other hand, the press bending may be such that the fulcrum does not rotate as shown in FIG. 4 (Non-Patent Document 2) other than the method using the bending die and the support roller as shown in FIG. Compared with the above-described pull bending, the press bending has the advantage that it requires less molds and can be bent only by moving the punch (bending die in FIG. 2), and thus has high productivity. However, since there are few constraints by surrounding molds, wrinkles and buckling are likely to occur inside the bend, and especially when the distance between the fulcrums is large, buckling is likely to bend at the punch pressing location.

  The pressing bending is a method of bending the pipe material while the pressing mold rotates around the bending mold as shown in FIG. It is relatively similar to the above-described bending, and is the difference between the bending mold rotating and the pressing mold rotating. In addition to the case of using a mold as shown in FIG. 3, there is an example in which a roll is used as shown in FIG. 5 (Patent Document 1) (in FIG. 5, (a) to (d) 1 to 4 of Patent Document 1 are shown, wherein 1 is a fixed mold, 2 is a guide surface, 3 is a groove, 4 is a support shaft, 4a is a pinion rack, 5 is a hydraulic cylinder for pressing, 6 Is a bearing frame, 7 is a pressing die, 7a is a support shaft, 8 is a groove, 9 is a hydraulic cylinder for rotation, 10 is a hole type, P is a material pipe, and Pa is a tip portion). However, the bending shape is limited to a circular arc, and the disadvantage that bending with a large bending radius is difficult in terms of equipment is the same as in the case of drawing bending.

“Tube Forming” pages 36-64 (published by Corona on October 30, 1992) Plasticity and processing, Vol.44, No.508 (2003), p.530 JP-A-3-32427

  As described above, existing pipe bending devices and methods can be bent with a large bending radius that does not require large-scale equipment and dies, bending that does not easily wrinkle or buckle inside the bend, and high productivity. The three characteristics of bending cannot be compatible. Therefore, an object of the present invention is to provide a new pipe bending apparatus and bending method that can satisfy both of these three characteristics.

In order to solve the problem, the gist of the present invention is as follows.
(1) In a press bending apparatus that performs three-point bending of a tube material with a punch and a set of rolls, the punch has a groove on the outer periphery that is wider than the width of the tube material, and the set of rolls is supported by a frame And can move on the frame in a direction away from each other while being in contact with the punch, and the frame is a cavity for allowing the punch and the tube to move during bending of the tube A press bending apparatus for a pipe material, characterized by comprising a portion.
(2) In a press bending apparatus that bends while pressing a pipe against the punch with a single roll while a part of the pipe is fixed to the punch, the punch has a groove on the outer periphery that is wider than the width of the pipe. The roll is supported by a pedestal and is movable in contact with the punch, and the pedestal has a hollow portion for allowing the punch and the tube to move during bending of the tube. A press bending apparatus for pipe materials, characterized by
(3) A part or all of the cross-sectional shape of the center portion of the roll and the groove of the punch is formed of a semicircular shape, an ellipse shape, a rectangular shape, a polygonal shape, or a combination of curves, The press bending apparatus for pipe materials according to (2).
(4) Any one of the above (1) to (3), wherein a part of the pipe material is bulged and a hollow portion into which the bulged portion can be mounted is provided in the punch. The press bending apparatus for pipe materials according to Item.
(5) The press bending apparatus for a pipe material according to any one of (1) to (4), wherein the roll is rotatable with respect to the gantry.
(6) The press bending apparatus for a pipe material according to any one of (1) to (5), wherein the roll is rotatable with respect to the punch.
(7) The tube bending press apparatus according to (6), further comprising a driving unit that rotationally drives the roll in a direction in which the tube is advanced toward the tube end.
(8) The press bending apparatus for a pipe material according to (6), further including a driving unit that rotationally drives the roll in a direction in which the pipe material is advanced in a direction opposite to the pipe end.
(9) The press bending apparatus for a tube material according to any one of (1) to (8), wherein the roll is movable with respect to an axial direction of the roll.
(10) The press bending of the pipe material according to any one of (1) to (9), wherein a surface of the gantry on which the roll moves forms an acute angle with respect to a traveling direction of the punch. Processing equipment.
(11) A tube material is inserted into a groove provided on the outer periphery of the punch, and a pair of rolls positioned on the opposite side of the punch with respect to the tube material and supported by a cage frame and one of the punches The tube is clamped by the section, the punch is moved to the gantry side, the pair of rolls are moved on the gantry in a direction away from each other while being in contact with the punch, and the tube material is moved to the punch. A method of press bending a pipe material, characterized by bending along a groove shape.
(12) In a state where a part of the tube material is fixed to the punch, the tube material and the punch are pressed together with one roll located on the opposite side of the punch from the tube material and supported by the frame. A part of the punch is brought into contact with the roll, the roll and the tube material are sandwiched in a groove provided in the punch, the punch is further moved to the roll side, and the roll is moved. A tube material press bending method, wherein the tube material is bent along the groove shape of the punch by moving on the frame along the punch while being in contact with the punch.
(13) A part or all of the cross-sectional shape of the central portion of the roll and the groove of the punch is formed of a semicircular shape, an ellipse, a rectangular shape, a polygonal shape or a combination of curves, and the punch and the roll. The method of press bending a pipe material according to (11) or (12), wherein the cross-sectional shape is deformed and bent at the same time.
(14) The press bending method for a pipe material according to any one of (11) to (13), wherein the pipe material is bent using a partially expanded pipe material.
(15) The method of press bending a pipe material according to any one of (11) to (14), wherein the roll is bent while being rotated with respect to the gantry.
(16) The press bending method for a pipe material according to any one of (11) to (15), wherein the bending is performed while rotating the roll with respect to the punch.
(17) The press bending method for a pipe material according to (16), wherein the bending is performed while the roll is rotationally driven in a direction in which the pipe material is advanced toward the pipe end.
(18) The press bending method for a pipe material according to (16), wherein the bending is performed while the roll is rotationally driven in a direction in which the pipe material is advanced in a direction opposite to the pipe end.
(19) The method of press bending a pipe material according to any one of (11) to (18), wherein the roll is bent while being moved in the axial direction of the roll.
(20) The press bending of a pipe material according to any one of (11) to (19), wherein the roll is bent while being moved at an acute angle with respect to a direction in which the punch proceeds. Method.

  According to the present invention, the conventional drawing bending and pressing bending can reduce the cost of bending with a large bending radius, which has been high in equipment cost and mold cost, and can be bent with high productivity. Reduction can also be achieved. On the other hand, in the conventional press bending, wrinkles and buckling occur inside the bend and bending is impossible, so that bending can be performed without generating wrinkles and buckling. This further expands the range of application of pipe bending parts for automobile parts, building material parts, furniture parts, etc., which not only contributes to weight reduction, but also reduces production costs.

  FIG. 6 shows an example in which the center of the circular pipe (tube material) 11 is bent into an arc shape by the processing apparatus according to the embodiment of the present invention. Hereinafter, details of the processing apparatus and the processing method of the present invention will be described with reference to this drawing. In the figure, a front view of the structure of the entire apparatus is shown on the left, and a side view is shown on the right. Further, the left side from the center line of the front view is an external view, and the right side from the center line is a central sectional view.

  First, the structure of the entire apparatus will be described. This apparatus includes a punch 12, a pair (two pieces) of rolls 13 and 13, and a mount 14. On the outer peripheral surface of the punch 12 in contact with the circular tube 11, a groove having the same cross section as the upper half of the circular tube 11, that is, a groove 12 a having a width equal to the diameter (width) of the circular tube 11 and a semicircular cross section is provided. is there. The central portion 31 of the roll 13 in contact with the circular tube 11 has a groove having the same cross section as the lower half of the circular tube 11, that is, a groove 13 a having a width equal to the diameter (width) of the circular tube 11 and a semicircular cross section. It is the shape of. The gantry 14 supporting the roll 13 has a cavity 14a having a width larger than any of the punch 12 and the circular tube 11 when viewed from the side, and the descending punch 12 and the circular tube 11 bent along therewith are provided. The cavity 14a can be moved freely. In this example, the gantry 14 has a structure that is completely divided into two parts. However, if there is a sufficiently large cavity, the gantry 14 may be integrated on the lower side of the gantry. Further, the pair of rolls 13 and 13 are installed on the gantry 14 and the end portion 30 of the roll 13 in contact with the outer circumference of the gantry 14 and the punch 12 has a cylindrical shape so that it can move on the gantry 14. It has become.

  Next, the processing method of the present invention will be described in order from FIG. (a) shows an initial state. Two positions of the rolls 13 and 13 on the gantry 14 are arranged in the center. As shown in the figure, they may be in contact with each other, or a stopper or the like may be provided between the rolls 13 and 13 so as to be in contact therewith. In any case, a force (horizontal arrow in the figure) for pressing the rolls 13 and 13 in a direction approaching each other is loaded. The force loading method may be performed by a hydraulic cylinder or a spring. As described above, the circular tube 11 is placed further above the set of rolls 13 and 13 installed on the gantry 14.

  Next, as shown in FIG. 4B, the punch 12 is lowered (advanced toward the gantry 14) from above the circular tube 11. Then, the circular tube 11 is sandwiched between the semicircular groove 12 a of the punch 12 and the semicircular groove 13 a of the central portion 31 of the roll 13. At the same time, the punch 12 and the end 30 of the roll 13 are in contact with each other at the outer portion of the grooves 12a and 13a. Since the center of the outer peripheral surface of the punch 12 in this example is arcuate, when the punch 12 is pushed downward in the vertical direction, a force is exerted to move the rolls 13 and 13 away from each other (outside). However, as described above, the rolls 13 and 13 have a force to bring them closer to each other. As a result, the end portions 30 of the rolls 13 and 13 are punched while being in contact with the punch 12 as the punch 12 is lowered. 12 is moved on the gantry 14 along the outer peripheral surface of 12. By the movement of the rolls 13 and 13 as described above, the circular tube 11 is bent so as to be pressed against the punch 12 by the pair of rolls 13 and 13.

  Finally, as shown in FIG. 5C, when the roll 13 reaches the straight portion of the punch 12, the bending process is completed. In addition, when removing the circular tube 11 after bending, it can be easily taken out by simply raising the punch 12.

  The above is description of the press bending apparatus and method of a pipe material in the case of using 1 set of rolls 13 proposed in the invention according to (1) and the invention according to (11). Next, with reference to FIG. 7, an apparatus and a method for press bending a pipe material when using one roll 13 proposed in the invention according to (2) and the invention according to (12) will be described.

  FIG. 7 shows an example in which the punch 12 is disposed below and the gantry 14 and the roll 13 are disposed above. First, the right end of the circular tube 11 is fixed on the punch 12 using the fixing jig 15. A groove 12a having a width equal to the diameter (width) of the circular tube 11 is provided on the outer peripheral surface of the punch 12 which is in contact with the circular tube 11 and having a semicircular groove having the same cross section as the lower half of the circular tube 11. is there. The central portion 31 of the roll 13 in contact with the circular tube 11 has a drum-like shape having a groove made of a semicircle having the same cross section as the upper half of the circular tube 11, that is, a groove 13 a having a width equal to the diameter (width) of the circular tube 11. It has become. The gantry 14 supporting the roll 13 has a cavity 14a having a width larger than any of the punch 12 and the circular tube 11 when viewed from the side, and the punch 12 and the circular tube 11 are movable in the cavity 14a. Yes. In addition, a T-shaped protrusion 13b is provided at the upper portion of the end portion 30 of the roll 13 in contact with the gantry 14, and a guide groove 14b having a cross section that matches the cross section of the protrusion 13b is formed at the lower portion of the gantry 14. Yes. The protrusion 13 b of the roll 13 is fitted into the guide groove 14 b of the gantry 14, and the roll 13 is supported by the gantry 14. At the same time, the roll 13 is guided by the guide groove 14 b and can move along the lower surface of the gantry 14. Moreover, the outer peripheral part of the punch 12 and the end part 30 of the roll 13 in contact with the mount 14 are cylindrical.

  According to such an example, the gantry 14 and the roll 13 are lowered in a direction in which the punch 12 and the circular tube 11 are present in an integrated state. A force pressing in the right direction (the horizontal arrow direction in the figure) is applied to the roll 13, and as a result, the roll 13 moves while being in contact with the punch 12 as the gantry 14 and the roll 13 are lowered. Therefore, the circular tube 11 sandwiched between the roll 13 and the punch 12 is bent into a shape along the groove 12 a of the punch 12. Finally, when the roll 13 reaches the straight portion of the punch 12, the bending process is completed. After that, when the gantry 14 and the roll 13 are raised, the bent circular pipe 11 can be taken out.

  In the example of FIG. 6 described above, the punch 12 is disposed on the upper side, and in the example of FIG. 7, the punch 12 is disposed on the lower side. That is, the punch 12 in the example of FIG. 6 may be disposed below, the circular tube 11 may be placed thereon, and the mount 14 and the roll 13 may be lowered from above, or the mount 14 and the roll 13 in the example of FIG. The punch 12 which is disposed below and fixes a part of the circular tube 11 may be lowered together with the circular tube 11 from above. Further, these arrangements may be arranged not in the vertical direction but in the horizontal direction, and the punch 12 or the gantry 14 and the roll 13 may be moved in the horizontal direction.

  The first advantage of the present invention is that the cost is low because the device is simple. Basically, it is only necessary to have a press device, and the device is simple and low-cost. Further, when bending different bending shapes, only the punch 12 needs to be recreated. Since the roll 13 and the gantry 14 can be used in common, the die cost can be reduced.

  The second advantage is high productivity. In normal bending, it takes about 20-30 seconds for one bend, and it may take more than 1 minute for multiple bends. In contrast, the bending method of the present invention can be bent in a few seconds because it can be bent with a single press.

  A third advantage is that wrinkles and buckling are unlikely to occur. In press bending by three-point bending with the fulcrum position fixed, wrinkles and buckling tend to occur inside the bending. However, in the bending method according to the present invention, since the distance between the fulcrums, that is, the distance between the rolls 13 and 13 or the distance between the roll 13 and the fixing jig 15 is initially short, bending is unlikely to occur, and the bending process proceeds. Along with this, the distance between the fulcrums gradually expands and bends sequentially, so that finally a shape without wrinkles or buckling can be formed.

  In this example, the tube 11 is bent, but the cross-sectional shape of the tube material does not have to be circular, and as shown in the examples of FIGS. 8A to 8C, an ellipse, a rectangle, and other irregular cross-sections are used. In addition, the present invention is applicable. In addition, as shown in the example of FIG. 8D, the present invention can be applied to a pipe material having an inner rib such as a sun-shaped cross section produced by an aluminum extruded material or a pipe material having a rib on the outer side. . In that case, what is necessary is just to make the cross-sectional shape of the groove | channel 12a of the punch 12, and the cross-sectional shape of the groove | channel 13a of the center part 31 of the roll 13 into the shape suitable for each cross-sectional shape of a pipe material.

  Further, as in the example of FIG. 9, a processed product 16 preformed by hydroforming or the like may be used. FIG. 4A is an example in which there is an expanded portion 16a of hydrofoam as a bulging portion on the side where the rolls 13 and 13 are present. In this case, the position does not interfere with the rolls 13 and 13 in the initial state. If the pipe expansion part 16a can be arrange | positioned in this, the bending method of this invention can be utilized as it is. FIG. 5B is an example in which the expanded portion 16a of the hydrofoam is present in the direction in which the punch 12 is present. In this case, the excavated portion 12b as a hollow portion is formed at a position corresponding to the expanded portion 16a of the punch 12 (FIG. In the example of 9, if the lower part of the center of the punch 12 is provided, the tube expansion portion 16 a can be formed without being crushed during bending.

  The shape for bending the circular tube 11 need not be an arc shape. The parabolic shape as shown in FIG. 10A may be used, and the present invention can also be applied to a hyperbolic shape or a sinusoidal shape. Moreover, the shape which combined those curves and a straight line like the same figure (b) may be sufficient.

  Further, the cross-sectional shape of the tube material 11 and the cross-sectional shapes of the grooves 12a and 13a in the central portion 31 of the punch 12 and the roll 13 do not have to be the same. For example, as shown in FIG. 11, the cross section of the tube material 11 may be circular, and the shapes of the grooves 12 a and 13 a in the central portion 31 of the punch 12 and the rolls 13 and 3 may be rectangular. If it processes by such a combination, the whole can be bent, deform | transforming the cross-sectional shape of the pipe material 11 from a circular shape to a rectangular cross section. Originally, if the tube material 11 having a rectangular cross section is bent, problems such as cross section deformation and buckling are likely to occur. However, as described above, if cross section deformation and bending are performed simultaneously, the cross section accuracy after processing is high and buckling is also possible. Hard to occur. Moreover, since it leads to process reduction and the number of molds, it is advantageous in terms of cost.

  In addition, the shape of the grooves 12a and 13a in the central portion 31 of the punch 12 and the rolls 13 and 13 may be a shape combining polygons or curves as shown in FIG. 12, but the tube material 11 is first inserted. The width of the grooves 12a and 13a needs to be equal to or greater than the width of the tube material 11 so that it can be made. The total length of the circumferential lengths of the punch 12 and the grooves 12a and 13a of the central portion 31 of the roll 13 is preferably substantially the same as the circumferential length of the tube material 11, but a slight size is acceptable. However, if the circumferential length of the grooves 12a and 13a is excessively large with respect to the circumferential length of the tube material 11, the accuracy of the cross-sectional shape after bending is deteriorated. On the contrary, if the circumferential length is excessively small, wrinkles may occur. is there.

  Further, the cross-sectional shapes of the grooves 12a and 13a need not be uniform in the longitudinal direction. For example, as shown in FIG. 13A, when the cross section of the groove 12a of the punch 12 is changed in the longitudinal direction, the tube material 11 is deformed into a cross-sectional shape in which both ends are square and the other part is circular, and is bent at the same time. Further, as shown in FIG. 2B, the cross section of the groove 13a in the central portion 31 of the roll 13 may be repeatedly changed into a circular cross section and a quadrangular cross section in the circumferential direction. However, as described above, since the sum of the circumferential lengths of the groove 12a of the punch 12 and the groove 13a of the central portion 31 of the roll 13 is preferably the same as the circumferential length of the original tube material 11, the groove 12a of the punch 12 It is better to design the sum of the circumferential lengths of the grooves 13a in the central portion 31 of the roll 13 to be uniform.

  Next, the rotation of the roll 13 will be described. FIG. 14 shows a case where the roll 13 does not rotate with respect to the gantry 14 or the punch 12 and slides along the upper surface of the gantry 14. In order to achieve such an effect, the lower surface of the end portion 30 of the roll 13 in contact with the gantry 14 is a flat surface, and the upper portion of the roll end portion 30 in contact with the punch 12 has a semicircular shape. The cross section of the groove 13a of the central portion 31 of the roll 13 is semicircular. Advantages in this case include that the structure of the rolls 13 and 13 is simple, and that the tube member 11 is bent while being pulled in the longitudinal direction due to frictional resistance during bending, so that buckling is unlikely to occur. Can be mentioned. On the other hand, the disadvantage is that the rolls 13 and 13 are difficult to move because of high frictional resistance.

  On the other hand, FIG. 15 is an example in which the roll 13 slides without rotating with respect to the gantry 14 and moves while rotating with respect to the punch 12. In order to exhibit such an action, the lower surface of the end portion 30 of the roll 13 in contact with the gantry 14 is a flat surface. The central portion 31 of the roll 13 in contact with the punch 12 has a drum-like circular shape and is rotatable independently of the roll end portion 30. The cross section of the groove 13a of the central portion 31 of the roll 13 is semicircular. In this case, since the roll 13 can move with little resistance with respect to the punch 12, it is particularly effective when bending while changing the cross-sectional shape of the tube material 11 as shown in FIG. Further, as shown in FIG. 13B, the shape of the groove 13a in the central portion 31 of the roll 13 can be changed in the longitudinal direction to change the cross-sectional shape of the outer side of the tube 11 while changing the shape. However, the structure of the roll 13 becomes complicated, and the tensile force with respect to the pipe material 11 decreases. Therefore, as shown in FIG. 15B, if the rolls 13 and 13 are driven outward (that is, in a direction in which the tube 11 is advanced toward the tube end), the tensile force on the tube 11 is increased. This is effective in suppressing buckling during bending. On the contrary, when the rolls 13 and 13 are driven inwardly with respect to each other (that is, in a direction in which the pipe material 11 is advanced in the direction opposite to the pipe end) as shown in FIG. 15C, the movement resistance of the roll 13 can be reduced. . This is particularly effective when the contact angle between the contact surfaces of the punch 12 and the roll 13 is nearly horizontal, and the roll 13 can be smoothly moved outward in the initial stage of bending.

  As an example of a roll that rotates on the gantry 14 and slides with respect to the punch 12, a roll 17 having a flat contact portion with the punch 12 as shown in FIG. In order to exhibit such an action, the end portion 70 of the roll 17 in contact with the gantry 14 has a cylindrical shape, and the central portion 71 of the roll 17 in contact with the punch 12 has a rectangular parallelepiped outer shape. The roll end portion 70 is rotatable independently of the roll center portion 71, and the roll center portion 71 can freely follow the angle of the shape of the groove 12 a of the punch 12. The cross section of the groove 17a in the central portion 71 of the roll 17 is semicircular. In this case, the tube material 11 can be crushed on a wide surface, which is effective in preventing local crushing. Further, the central portion of the tube material 11 that cannot be crushed at the initial stage of bending with the circular roll 13 can be crushed by using the flat roll 17. Further, the flat rolls 17 and 17 are taken as an example of sliding with respect to the punch 12 and rotating with respect to the gantry 14 as shown in FIG. The present invention can also be applied to the case shown in FIG.

  Finally, FIG. 17 shows an example in which the rolls 13 and 13 rotate with respect to the gantry 14 and the punch 12. In order to exhibit such an action, the end portion 30 of the roll 13 in contact with the gantry 14 has a columnar shape, and the central portion 31 of the roll 13 in contact with the punch 12 has a drum-like circular shape. The roll end portion 30 and the roll center portion 31 are independently rotatable. The cross section of the groove 13a of the central portion 31 of the roll 13 is semicircular. The movement resistance of the roll 13 is smaller than in the examples shown in FIGS. 14 to 16 and the movement is smooth. However, since the tensile force in the longitudinal direction with respect to the tube material 11 is reduced, it is disadvantageous for buckling. It becomes.

  The rotation of the roll 13 has been described above. Next, the movement of the roll 13 in the axial direction will be described. As shown in FIG. 18, the shape of the groove 12 a of the punch 12 is changed in the short direction, and the central portion 31 of the roll 13 is movable with respect to the axial direction of the roll 13 so as to follow the shape. Then, it is also possible to bend the pipe material 11 into a three-dimensional shape.

  Next, the shape of the gantry 14 will be described. In the example described so far, for example, as shown in FIG. 6, the surface of the gantry 14 on which the roll 13 moves has an angle perpendicular to the traveling direction of the punch 12. However, when the angle of the contact surface between the punch 12 and the roll 13 is almost perpendicular to the moving direction of the punch 12, as in the initial stage of bending in FIG. It is difficult to move in the direction. Therefore, as shown in FIG. 19, the roll 17 can move smoothly even in the initial stage of bending by using a gantry 18 in which the angle of the surface on which the roll 17 moves is an acute angle with respect to the traveling direction of the punch 12. Further, when such a gantry 18 is used, even when the punch 12 has a flat central portion as shown in FIG. 19, the roll 17 can be smoothly moved from the initial stage.

  Examples of the present invention are shown below.

  As the tube material 11 of the circular pipe, STKM20A, a carbon steel pipe for mechanical structure having an outer diameter of 25.4 mm and a total length of 480 mm, was used, and the wall thickness t was set to two types of 2.0 mm and 1.6 mm. The steel pipe was processed by a process as shown in FIGS. 20 (a) to 20 (c). That is, as shown in FIG. 20A, the center of the tube material 11 was bent 90 ° into an arc shape with a bending radius of 203.2 mm (eight times the outer diameter). As shown in FIG. 14, the roll 13 is configured to slide without rotating with respect to the gantry 14 or the punch 12, and the dimensions are R = 25.4 mm on the outer side and the inner side (as shown in FIG. R = 12.7 mm at the groove bottom). That is, the lower surface of the end portion 30 of the roll 13 in contact with the gantry 14 is a flat surface, and the upper portion of the roll end portion 30 in contact with the punch 12 has a semicircular shape. The cross section of the groove 13a in the central portion 31 of the roll 13 is semicircular. The shape of the groove 13a was a semicircular cross section having the same diameter as the outer diameter of the tube material 11 on both the punch 12 side and the roll 13 side. As a final position, the punch 12 was pushed in until the distance between the centers of the two rolls 13 and 13 reached 400 mm.

  Although bending was performed under the same conditions using the same tube material 11 as in Example 1, only the structure of the roll 13 was changed. As shown in FIG. 21, the roll 13 has a structure in which a circular wheel 30 (the end 30 of the roll) can move while rotating on the gantry 14, and the drum-shaped roll center having a semicircular cross section with respect to the punch 12. The part 31 can move while rotating. The axle 32 connecting the wheel portion 30 on the gantry 14 and the drum-shaped roll center portion 31 that contacts the punch 12 is fixed to the roll center portion 31, but is free from the wheel portion 30. It has a structure that can be rotated. The dimensions of the roll 13 are such that the wheel portion 30 has an outer diameter of 48 mm, the outer diameter of the drum-shaped roll central portion 31 is 50.8 mm, and the distance between the grooves 13a and 13a is 25.4 mm.

  Using the same tube material 11, punch 12, gantry 14, and roll 13 as in Example 2, the punch 12 was pushed to the same position as in Example 2 and bent. However, bending was performed while driving the roll 13 to forcibly rotate it. In this example, as shown in FIG. 22, the roll 13 is driven by a driving means 40 that rotationally drives the roll 13 in a direction in which the tube material 11 is advanced toward the tube end. A chain 42 for rotating the motor 41 and the axle 32 of the roll 13 is disposed in the driving means 40, and the axle 32 is forcibly rotated from the motor 41 through the chain 42. That is, the direction of rotation was set so that the two rolls 13 and 13 were directed outward.

  In contrast to Example 3, only the driving direction of the roll 13 was reversed. That is, the drive means 50 which rotationally drives the roll 13 in the direction in which the pipe material 11 is advanced in the direction opposite to the pipe end is used. A chain 52 for rotating the motor 51 and the axle 32 of the roll 13 is arranged in the driving means 50, and bending is performed while the two rolls 13 and 13 are rotated inward toward each other (see FIG. 23). .

  Table 1 shows a list of the results of the presence or absence of buckling inside the bending and the indentation load when bending is performed in Examples 1 to 4 described above. For comparison, the result of the conventional three-point bending method is also shown. In addition, the fulcrum of the same shape as the roll 13 of Example 1 was used for the fulcrum of 3 point | piece bending, and the distance between fulcrum was set to 400 mm same as the final position of Examples 1-4.

  As a result, the bending of the 2.0-t-thick material that would buckle in conventional three-point bending was bent without buckling in any of Examples 1 to 4 by the method according to the present invention. However, in the case of a 1.6-t thin material, the condition of Example 2 in which the roll 13 rotates is not buckled under the condition of Example 1 in which the roll 13 slides with respect to the punch 12 or the mount 14. Then I buckled. Therefore, when the rolls 13 are driven to rotate outward as in the third embodiment, the tube material 11 is prevented from buckling due to the tensile force acting in the tube axis direction.

  However, under the condition that the roll 13 is slid or rotated outward, the pressing load of the punch 12 increases, which is disadvantageous from the viewpoint of minimizing the equipment capacity. On the other hand, when the rolls 13 are rotated inward as in the fourth embodiment, the pushing load can be reduced. The method of Example 4 is effective for bending a thick material that does not become a neck by buckling with a small force.

  FIG. 24 shows an example in which a processed product 16 obtained by primary processing of the pipe material 11 to be bent with a hydroform instead of a simple straight pipe is applied. First, hydroform the outer diameter 25.4mm, the wall thickness 2.0mm, the total length 540mm, steel grade STKM20A (the same material as the 2.0t material used in Examples 1 to 4 and 60mm long) The tube expansion part 16a having a height of 30 mm is formed into a protruding shape. As hydroform conditions at that time, the internal pressure was 105 MPa, and the axial push was 30 mm from both ends. Therefore, the length after hydroforming is 480 mm. Bending is performed with the expanded pipe portion 16a of the hydroformed product 16 disposed below. In this case, the shape of the punch 12 and the roll 13 and the distance between the final rolls 13 and 13 were the same as those in the first to fourth embodiments. On the other hand, it was set as slip conditions. As a result of the bending process, molding defects such as buckling were not observed, and a molded product having a good shape was obtained.

  FIG. 25 shows a rectangular cross section of the shape of the groove 12a of the punch 12 and the shape of the groove 13a of the central portion 31 of the roll 13 using the same tube material 11 as the 2.0t-thick material used in Examples 1 to 4. It is an example. The rectangle was designed with a width of 26.5 mm, a height of 8 + 8 = 16 mm, and a corner R = 3 mm. As for the circumference, the total circumference of the inner surfaces of the grooves 12a and 13a of the punch 12 and the roll 13 is 79.85 mm, while the outer circumference of the original pipe is 79.80 mm. did. The axial position of the groove 12a of the punch 12 was designed not to be on a plane parallel to the pushing direction but to pass on a plane inclined by 10 °. The roll end 30 is cylindrical so that the roll 13 can be moved in the axial direction, and the roll central part 31 is the axis of the roll 13 so that it can be moved during the bending process along the position of the groove 12 a of the punch 12. It was movable in the direction. Finally, the rolls 13 and 13 were pushed in until reaching the position of the pipe end, and the cross section was deformed over the entire length. Other conditions are the same as those in Example 2. As a result of bending with the above apparatus and processing conditions, a molded product having a rectangular cross section and a three-dimensional bending can be obtained from a straight pipe having a circular cross section by a single bending process.

  FIG. 26 shows an example in which the center portion of the punch 12 is bent in a flat shape. Moreover, the rolls 13 and 13 need to start moving from the center position for an example in which the cross section of the tube material 11 including the flat portion is deformed into a rectangle. Therefore, the gantry 18 is positioned with respect to the horizontal plane as shown in the figure so that the surface of the gantry 18 on which the end portions 30 of the rolls 13 and 13 move forms an acute angle with respect to the traveling direction of the punch 12 (downward in FIG. 26). The rolls 13 and 13 are easily moved outward by tilting downward by 15 °. Moreover, since the cross section of the roll center part 31 is also formed into a rectangle, the cross section of the roll center part 31 is not circular but rectangular. Moreover, the roll center part 31 and the roll end part 30 are rotatable independently, and the roll center part 31 can follow the angle formed by the shape of the groove 12 a of the punch 12. In addition, the same pipe material 11 as the 2.0t thick material used in Examples 1-4 was used for the pipe material 11. Finally, the rolls 13 and 13 were pushed in until reaching the position of the pipe end, and the cross section was deformed over the entire length. As a result of bending, a molded product having a rectangular cross section and bent at both ends was obtained.

  FIG. 27 shows an example in which the pipe material 11 is bent at one place by one roll 13. The shape of the grooves 12a and 13a of the punch 12 and the roll 13 was a simple circular cross section, and the same tube material 11 as the 2.0t material used in Examples 1 to 4 was used as the tube material 11. Further, the roll 13 slides with respect to the gantry 14 and rotates with respect to the punch 12 so that the upper surface of the roll end 30 in contact with the gantry 14 is a flat surface, and the lower part of the roll end 30 in contact with the outer periphery of the punch 12 is It has a semicircular shape (not shown). Moreover, the roll center part 31 was made into the drum shape which has the semicircular groove | channel 13a (not shown). The initial position of the roll 13 is pressed to a position as shown in FIG. As a result of the bending process, a molded product in which one side was a straight pipe and only the other side was bent was obtained.

  INDUSTRIAL APPLICABILITY The present invention is useful for bending pipe materials used for manufacturing automobile parts, building material parts, furniture parts, and pipes used in piping in various facilities.

Explanatory drawing of the conventional rotation drawing bending method is shown. An explanatory view of a conventional press bending method is shown. The explanatory view of the conventional press bending method is shown. An explanatory view of a press bending method in which a conventional fulcrum does not rotate is shown. The explanatory view of the conventional press bending method is shown. Explanatory drawing of the bending method in the case of using 1 set of rolls of this invention is shown. Explanatory drawing of the bending method in the case of using one roll of this invention is shown. Explanatory drawing of the cross-sectional shape of the pipe material used by this invention is shown. In this invention, explanatory drawing in the case of processing using a hydroform molded article is shown. The example of the bending shape to which this invention is applicable is shown. In the present invention, an explanatory diagram in the case of bending a pipe having a circular cross section while deforming to a rectangular cross section is shown. In this invention, the example of the groove | channel shape of a punch and a roll in the case of changing a cross-sectional shape after a bending process is shown. In the present invention, an example in which the groove-shaped cross section of the punch is changed in the longitudinal direction and an example in which the groove-shaped cross section of the roll is changed in the circumferential direction are shown. In this invention, explanatory drawing in case a roll slides also with respect to a punch and a mount frame is shown. In this invention, explanatory drawing in case a roll rotates with respect to a punch and slides with respect to a mount frame is shown. In this invention, explanatory drawing in case a roll slides with respect to a punch and rotates with respect to a mount frame is shown. In this invention, explanatory drawing in case a roll rotates with respect to a punch and a mount frame is shown. In the present invention, the roll is structured to be movable in the axial direction of the roll, and an explanatory view of a combination of a roll and a punch that can be bent into a three-dimensional shape is shown. In this invention, explanatory drawing in case the upper surface of a mount frame is an acute angle with respect to the advancing direction of a punch is shown. An explanatory view of Example 1 of the present invention is shown. An explanatory view of Example 2 of the present invention is shown. An explanatory view of Example 3 of the present invention is shown. An explanatory view of Example 4 of the present invention is shown. An explanatory view of Example 5 of the present invention is shown. Explanatory drawing of Example 6 of this invention is shown. An explanatory view of Example 7 of the present invention is shown. Explanatory drawing of Example 8 of this invention is shown.

Explanation of symbols

11 Round pipe (pipe material)
DESCRIPTION OF SYMBOLS 12 Punch 12a Groove 12b Excavated part 13 Roll 13a Groove 14 Mount 14a Cavity 15 Pipe material fixing jig 16 Hydroform processed product 16a Expanded part 17 Flat roll 18 Mount 30 in which slide surface of roll is inclined 30, 70 End of roll 31, 71 Central part of roll 40 Driving means for rotationally driving the roll in a direction for advancing the pipe material toward the pipe end 50 Driving means for rotationally driving the roll in a direction for advancing the pipe material in the direction opposite to the pipe end

Claims (20)

In a press bending machine that performs three-point bending of pipes with a punch and a set of rolls,
The punch has a groove having a width equal to or greater than the width of the tube material on the outer periphery,
The set of rolls are supported by a gantry, and are movable on the gantry in a direction away from each other in contact with the punch,
The said base has a hollow part for making the said punch and the said pipe material movable during bending of the said pipe material, The press bending process apparatus of the pipe material characterized by the above-mentioned. In a press bending apparatus that bends while pressing a pipe against the punch with a single roll while a part of the pipe is fixed to the punch,
The punch has a groove having a width equal to or greater than the width of the tube material on the outer periphery,
The roll is supported by a gantry and is movable in contact with the punch;
The said base has a hollow part for making the said punch and the said pipe material movable during bending of the said pipe material, The press bending process apparatus of the pipe material characterized by the above-mentioned. 3. A tubular material according to claim 1 or 2, wherein a part or all of the cross-sectional shape of the central portion of the roll and the groove of the punch has a semicircular shape, an elliptical shape, a rectangular shape, a polygonal shape, or a combined shape of curves. Press bending machine. The pipe material press according to any one of claims 1 to 3, wherein a part of the pipe material is bulged and a hollow portion in which the bulged portion can be mounted is provided in the punch. Bending device. The pipe bending press apparatus according to any one of claims 1 to 4, wherein the roll is rotatable with respect to the gantry. The pipe bending apparatus according to any one of claims 1 to 5, wherein the roll is rotatable with respect to the punch. The press bending apparatus for a pipe material according to claim 6, further comprising a drive unit that rotationally drives the roll in a direction in which the pipe material is advanced toward the pipe end. The press bending apparatus for a pipe material according to claim 6, further comprising a drive unit that rotationally drives the roll in a direction in which the pipe material is advanced in a direction opposite to the pipe end. The press bending apparatus for a pipe material according to any one of claims 1 to 8, wherein the roll is movable with respect to the axial direction of the roll. The press bending apparatus for a pipe material according to any one of claims 1 to 9, wherein the surface of the gantry on which the roll moves forms an acute angle with respect to the direction of punch movement. Insert the pipe material into the groove provided on the outer periphery of the punch,
The tube is sandwiched by a pair of rolls and a part of the punch, which is located on the opposite side of the punch with respect to the tube and supported by the gantry, and the punch is moved to the gantry,
A method of press bending a tube material, wherein the set of rolls are moved on the frame in a direction away from each other while being in contact with the punch, and the tube material is bent along the groove shape of the punch. With a part of the tube fixed to the punch,
The tube and the punch are pressed against a single roll located on the opposite side of the punch with respect to the tube and supported by the gantry,
A part of the punch is brought into contact with the roll, the roll and the tube material are sandwiched in a groove provided in the punch, and the punch is further moved to the roll side,
A method of press bending a tube material, wherein the roll is moved on a frame along the punch while being in contact with the punch, and the tube material is bent along the groove shape of the punch. At the same time that the cross-sectional shape of the tube material is deformed by using a punch and a roll in which all or a part of the cross-sectional shape of the central portion of the roll and the groove of the punch is a semicircular shape, an oval shape, a rectangular shape, a polygonal shape, or a combination of curves. The pipe material press bending method according to claim 11 or 12, wherein bending is performed. 14. The method of press bending a pipe material according to any one of claims 11 to 13, wherein a part of the pipe material is subjected to a bending process. The pipe material press bending method according to any one of claims 11 to 14, wherein the bending is performed while rotating the roll with respect to the gantry. The pipe material press bending method according to any one of claims 11 to 15, wherein the bending is performed while rotating the roll with respect to the punch. The method of bending a pipe material according to claim 16, wherein the bending is performed while rotating the roll in a direction in which the pipe material is advanced toward the pipe end. The method of press bending a pipe material according to claim 16, wherein the bending is performed while rotating the roll in a direction in which the pipe material is advanced in a direction opposite to the pipe end. The method for bending a pipe material according to any one of claims 11 to 18, wherein the bending is performed while moving the roll in the axial direction of the roll. The method of press bending a pipe material according to any one of claims 11 to 19, wherein the bending is performed while moving the roll at an acute angle with respect to the advancing direction of the punch.

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