JP2021058896A - Metal pipe molding device and metal pipe molding method - Google Patents

Abstract

To provide a metal pipe molding device and a metal pipe molding method capable of suppressing production cost, suppressing scuffing wear of a metal mold when processing a metal plate into a toric shape by UO molding, and enhancing circularity of the metal pipe as possible.SOLUTION: A U bending device 10 comprises: a bottom tool 20 which is fixed on a base 11, has a U-shaped recess 23 which becomes hollow downward, and on which a metal plate 100 is mounted; a top tool 30 which is fixed to a ramp 12, and has a punch 32 for pressing the metal plate 100 mounted on the bottom tool 20 toward the U-shaped recess 23; and a pair of curve formation parts 42 being formed on one of the bottom tool 20 and top tool 30, for forming a tip end curve part being curved on tip end parts of respective standing wall parts so that the tip end curve parts approach each other, with respect to a pair of standing wall parts extending in a vertical direction, the standing wall parts being formed on the metal plate 100 when the metal plate 100 is pressed toward the U-shaped recess 23 by the top tool 30.SELECTED DRAWING: Figure 1

Description

The techniques disclosed herein belong to the technical fields relating to metal tube molding devices and metal tube molding methods.

Conventionally, when forming a metal tube, a metal plate is bent into a U shape, and then the metal plate bent into a U shape is pressed from the U-shaped opening side to be processed into an annular shape, so-called UO molding. Is widely used.

For example, Patent Document 1 describes a lower die having a recess for accommodating the lower side of a work material made of a U-shaped bent metal plate material whose upper side is opened in advance, and a work material set in the lower die. It is provided with two side dies for molding the side surface portions of the above and an intermediate die for molding the upper portion of the work material, and after pressing both side surface portions of the work material with each side mold, the intermediate dies are formed. A pipe making device for forming an upper portion of a work material by a mold is disclosed.

Further, in Patent Document 2, metal is formed by CUO forming in which both ends of a metal plate in the width direction are bent in a C shape, the metal plate is bent in a U shape, and then the metal plate is bent in an annular shape. A method of obtaining a tube is disclosed.

JP-A-2019-104025 Japanese Unexamined Patent Publication No. 2003-285117

By the way, when processing a U-shaped bent metal plate into an annular shape, the metal plate is pressed from the U-shaped opening side by a ring processing device with a mold having a semicircular concave surface. Is common. At this time, the processing proceeds while the edge of the end portion of the metal plate slides on the concave surface of the mold. For this reason, wear (so-called galling wear) in which the concave surface of the mold is scraped off by the edge of the end portion of the metal plate progresses. If galling wear progresses on the concave surface of the mold, the concave surface may be deformed and the roundness of the finally formed metal tube may be lowered.

In the pipe making device described in Patent Document 1, a pair of standing wall portions continuous with a curved portion of a U-shaped metal plate are brought close to each other in advance by a side mold to narrow the U-shaped opening, thereby preventing galling wear. The amount is decreasing. However, since the upper mold is divided into three, there is a possibility that the divided portions of each mold may be displaced, and the roundness of the metal tube to be formed may be lowered.

On the other hand, as in Patent Document 2, it is conceivable to perform a C-bending process before bending the metal plate into a U-shape. However, a device and a process for performing the C bending process are required, which increases the manufacturing cost.

The technique disclosed here has been made in view of these points, and the purpose thereof is an annulus when processing a metal plate into an annulus by UO molding while suppressing a manufacturing cost. The purpose is to suppress galling wear of the mold of the processing device and to make the roundness of the metal tube to be formed as high as possible.

In order to solve the above problems, the first aspect of the technique disclosed herein is a U-bending device that bends a metal plate into a U-shape, and a metal plate that is bent into a U-shape by the U-bending device. For a metal tube forming apparatus having an annular processing apparatus that presses from the U-shaped opening side with a mold to process into an annular shape, the U-bending apparatus includes a base installed on a floor surface and the base. An elevating table that is arranged so as to be able to move up and down on the upper side of the base, and a lower mold that is fixed on the base and has a recessed recess on the lower side on which the metal plate is placed. An upper mold having a punch fixed to the lift and pressing the metal plate placed on the lower mold toward the recess, and a metal plate provided on either the lower mold or the upper mold. Is pressed toward the concave portion by the upper mold so that the pair of vertical wall portions extending in the vertical direction, which are formed on the metal plate, are close to the tip portions of the respective vertical wall portions. It is characterized by including a pair of curved forming portions each forming a curved tip curved portion.

A second aspect of the technique disclosed herein is, in the first aspect, the punch having a pressing portion that actually enters the recess and presses the metal plate, the pressing portion being in the recess. A lower surface portion having a corresponding outer edge shape, a pair of side surface portions extending straight upward from a pair of upper end portions of the lower surface portion, and curved so as to approach each other from the upper end portion of each of the side surface portions toward the upper side. It has a pair of upper surface portions, and each curved tip curved portion is formed by bending the tip portion of the standing wall portion along the upper surface portion by the curved forming portion.

A third aspect of the technique disclosed herein is, in the second aspect, each of the curved forming portions has a curved concave surface portion recessed so as to correspond to the shape of the upper surface portion, and the upper surface portion thereof. By pressing each of the standing wall portions from the side with each of the curved forming portions so that the tip portion of the standing wall portion is sandwiched between the curved concave portion and the curved concave portion, the tip curved portion is formed. It is a feature.

A fourth aspect of the technique disclosed herein is, in the third aspect, to bring the curved forming portions closer to the other of the lower mold or the upper mold as the lifting table is lowered. Is provided with a cam portion that moves in the horizontal direction.

A fifth aspect of the technique disclosed herein is, in any one of the first to fourth aspects, in each of the curved forming portions, the punch enters the recess and punches the metal plate. It is characterized in that it is configured so that the tip end portion of each of the standing wall portions is curved after being sandwiched between the lower mold and the lower mold.

A sixth aspect of the technique disclosed herein is, in any one of the first to fourth aspects, in a metal plate bent into a U shape by the U bending device, the tip of each of the standing wall portions. Each end of the curved portion is connected to each other on the opposite side of the curved portion, and the curved portion is used as the bottom wall portion. , Each of the standing wall portions is configured to be curved.

A seventh aspect of the technique disclosed herein is a U-bending step of bending a metal plate into a U-shape, and a metal plate bent into a U-shape by the U-bending step from the U-shaped opening side by a mold. In the U-bending step, the metal plate is placed on a lower mold having a recessed portion on the lower side, targeting a metal tube forming method in which a metal tube is formed by a ring processing step of pressing and processing into an annular shape. A mounting step, a pressing step of pressing the metal plate placed on the lower mold toward the recess by an upper mold having a punch having a shape corresponding to the recess, and a pressing step of pressing the metal plate on the metal plate. It is characterized by including a tip processing step of forming a tip curved portion curved so as to approach each other at the tip of each standing wall portion to be formed with respect to a pair of standing wall portions extending in the vertical direction. And.

According to the first and seventh aspects of the technique disclosed herein, when the metal plate is bent in a U shape (hereinafter referred to as U-bending), a tip curved portion is formed at the tip of each standing wall portion. As a result, when the ring processing device is used to process the ring into an annular shape, the mold of the ring processing device can be brought into contact with the curved surface of each curved tip. When the die of the ring processing device comes into contact with the curved surface of each curved tip portion, it is suppressed that the die is scraped by the tip portion of each standing wall portion. As a result, it is possible to suppress galling wear of the mold of the ring processing apparatus when the metal plate is processed into an annular shape by UO molding.

Further, since it is not necessary to excessively divide the mold of the ring processing apparatus, it becomes easy to increase the roundness of the metal tube to be formed.

Further, since the processing of bending the end portion in the width direction of the metal plate (C bending processing) is not separately required, the manufacturing cost can be suppressed.

According to the second aspect of the technique disclosed herein, the shape of each tip curved portion is formed by bending the tip portion of the standing wall portion along the upper surface portion of the punch to form each tip curved portion by the curved forming portion. It becomes easier to make the shape more appropriate. As a result, galling wear of the mold of the ring processing apparatus can be suppressed more effectively.

According to the third aspect of the technique disclosed herein, each tip is formed by sandwiching the tip of the standing wall portion between the upper surface portion of the punch and the curved concave surface portion of the bending forming portion to form each tip bending portion. It becomes easier to make the shape of the curved portion more appropriate. In addition, it becomes easy to maintain the shape of each curved tip. As a result, galling wear of the mold of the ring processing apparatus can be suppressed more effectively.

According to the fourth aspect of the technique disclosed herein, since the curved forming portions can be brought close to each other as the elevating table descends, it is necessary to separately prepare a drive source for moving each curved forming portion. It is possible to reduce the cost.

According to a fifth aspect of the technique disclosed herein, a metal plate is bent into a U shape by a punch and a lower mold to form a pair of standing wall portions, and then each curved tip portion is formed. This makes it easier to make the shape of the U-shaped metal plate more appropriate. As a result, the roundness of the formed metal tube can be improved.

According to the sixth aspect of the technique disclosed herein, since the curvature of each tip curved portion is substantially the same as the curvature of the bottom wall portion, the mold of the ring processing device is more effective than the curved surface of each tip curved portion. You will be able to make contact with each other. As a result, galling wear of the mold of the ring processing apparatus can be suppressed more effectively.

Further, the processing by the ring processing apparatus becomes easy, and the roundness of the metal tube to be formed can be increased more easily.

FIG. 5 is a cross-sectional view of a U-bending device according to an exemplary embodiment, showing a state in which the upper die is at the top dead center position. It is an enlarged view which shows the lower mold main body and the punch part of the U bending apparatus. It is sectional drawing of the O bending apparatus, and shows the state in which the upper die is at the position of the top dead center. It is an operation diagram of the U bending apparatus, and shows the state in which a metal plate is placed on the lower mold. FIG. 5 is an operation diagram of the U bending device, showing a state in which the punch presses the counter punch from the state of FIG. FIG. 5 is an operation diagram of the U-bending device, showing a state in which the punch has entered the recess of the lower mold from the state of FIG. FIG. 5 is an operation diagram of the U-bending device, showing a state in which each standing wall portion is pressed by each bending forming portion from the state of FIG. FIG. 5 is an operation diagram of the U-bending device, showing a state in which the upper mold is released from the state shown in FIG. It is an operation diagram of the O bending apparatus, and shows the state in which the pre-processed product is placed. It is an operation diagram of the O bending apparatus, and shows the state in which the split die is in contact with the preprocessed product from the state of FIG. It is an operation diagram of the O bending apparatus, and shows the state which O bending is completed from the state of FIG.

Hereinafter, exemplary embodiments will be described in detail with reference to the drawings. The following description of the preferred embodiment is essentially merely an example.

1 to 3 show a cross-sectional view of the metal tube forming apparatus 1 according to the present embodiment. The metal tube forming apparatus 1 is an apparatus for processing a metal plate 100 into a metal tube P by UO forming. The metal tube forming device 1 is a U-bending device 10 that bends a flat metal plate 100 into a U-shape, and a metal plate 100 that is bent into a U-shape by the U-bending device 10 in an annular shape, particularly in a cross section O. It has an O-bending device 50 for processing into a character shape. 1 and 2 are U bending devices 10, and FIG. 3 shows an O bending device 50. In the following description, the process of bending the metal plate 100 into a U shape is simply referred to as a U-bending process, and the process of bending the metal plate 100 into an O shape is simply referred to as an O-bending process. Further, in the following description, the metal plate 100 after the U-bending process may be referred to as a preprocessed product 150. Further, in the following description, the vertical direction and the horizontal direction will be described according to the arrows shown in each drawing, but this does not limit the direction in the actual usage state.

In the present embodiment, the metal plate 100 to be processed is, for example, a steel plate. Specifically, as the metal plate 100, a plate material such as a high-strength steel plate can be used. Finally, the obtained metal tube P is used for, for example, a propeller shaft of an automobile.

<U bending device>
As shown in FIG. 1, the U-bending device 10 is configured symmetrically. The U-bending device 10 has a base 11 installed on the floor surface F, and an elevating base 12 arranged so as to be able to move up and down on the upper side of the base 11 facing the base 11. The lower mold 20 is fixed on the base 11, while the upper mold 30 is fixed on the elevating base 12. Further, the lower mold 20 is provided with a pair of slide molds 40 that press the metal plate 100 from the left and right.

The lower mold 20 has a lower mold main body 21 and a processing die 22 provided at the center of the lower mold main body 21 in the left-right direction. The processing die 22 has a U-shaped recess 23 that is recessed in a U shape from the upper side to the lower side. As shown in FIG. 2, the U-shaped recess 23 includes a pair of vertical surface portions 23a extending straight in parallel in the vertical direction and a pair of curved bottom surfaces curved so as to approach each other from the lower end portions of each vertical surface portion 23a. It has a part 23b. Both corners between the vertical surface portions 23a and the upper surface of the processing die 22 are R-chamfered and curved.

At the center of the U-shaped recess 23 in the left-right direction of the processing die 22, a counter punch 24 protruding upward from the lower end of the U-shaped recess 23 is arranged. The upper surface 24a of the counter punch 24 is recessed downward. More specifically, the shape of the upper surface 24a of the counter punch 24 is a pair of curved bottom surfaces when the upper surface 24a of the counter punch 24 is at the same height as the curved bottom surface 23b of the U-shaped recess 23. It has a shape continuous with 23b.

A lower air cylinder 25 connected to the counter punch 24 is built in the center of the lower mold 20 in the left-right direction. The lower air cylinder 25 urges the counter punch 24 upward. Further, the lower air cylinder 25 acts as a cushion that absorbs an impact when the counter punch 24 is pressed by the upper mold 30. When the counter punch 24 is pressed by the punch 32 of the upper die 30, the cylinder rod 25a of the lower air cylinder 25 moves into the cylinder case, so that the counter punch 24 moves downward.

A pair of stopper portions 26 projecting upward are provided at the left-right end portions of the lower mold main body 21. As will be described in detail later, each stopper portion 26 limits the movement of each slide type 40 so that each slide type 40 does not move excessively when the pair of slide types 40 move in the left-right direction so as to separate from each other. It is a part to do.

The upper mold 30 has an upper mold main body 31 and a punch 32 arranged so as to vertically penetrate the central portion of the upper mold main body 31 in the left-right direction.

The punch 32 includes a block-shaped main body 33, a rod portion 34 extending downward from the lower surface of the main body 33, a pressing portion 35 provided at the lower end of the rod portion 34, and the punch 32 from the upper surface to the upper side of the main body 33. It has a pair of guide pins 36 extending toward each other. The rod portion 34 is provided at the center of the main body portion 33 in the left-right direction. The pair of guide pins 36 are provided at both left and right end portions of the main body portion 33 in the left-right direction.

The pressing portion 35 is a portion that enters the U-shaped recess 23 of the processing die 22 and presses the metal plate 100. As shown in FIG. 2, the peripheral surface of the pressing portion 35 extends straight upward from the lower surface portion 35a having an outer edge shape corresponding to the U-shaped recess 23 of the processing die 22 and the left and right upper ends of the lower surface portion 35a. It has a pair of side surface portions 35b and a pair of upper surface portions 35c curved so as to approach each other from the upper end portion of each side surface portion 35b toward the upper side. When the metal plate 100 is U-bent, the lower surface portion 35a faces the curved bottom surface portion 23b and the upper surface 24a of the counter punch 24 with the metal plate 100 interposed therebetween. The lower half of each side surface portion 35b faces the vertical surface portion 23a with the metal plate 100 in between during the U-bending process of the metal plate 100. When the metal plate 100 is U-bent, the upper half of each side surface portion 35b faces the curved forming portion 42 of the slide mold 40, which will be described later, with the metal plate 100 interposed therebetween. The upper surface portion 35c faces the curved forming portion 42 of the slide type 40 and the metal plate 100 with the metal plate 100 in between during the U-bending process of the metal plate 100.

An upper air cylinder 38 connected to the main body 33 is built in the center of the upper main body 31 in the left-right direction. The upper air cylinder 38 urges the punch 32 downward. Further, the upper air cylinder 38 acts as a cushion that absorbs the repulsive load from the metal plate 100 when the pressing portion 35 presses the metal plate 100. When the elevating table 12 is lowered while the metal plate 100 is sandwiched between the punch 32 and the processing die 22, the cylinder rod 38a of the upper air cylinder 38 moves into the cylinder case, and the punch 32 moves to the upper die body 31. It moves relative to it.

A pair of cam portions 39 are projected downward from each of the left and right side portions of the upper mold main body 31 in the left-right direction. As shown in FIG. 1, the pair of cam portions 39 are formed so as to be symmetrical. Specifically, the cam surface 39a of the left cam portion 39 is inclined upward toward the right side. On the other hand, the cam surface 39a of the cam portion 39 on the right side is inclined upward toward the left side. As will be described in detail later, each cam portion 39 is a portion that moves the curved forming portions 42 of each slide type 40 in the horizontal direction (horizontal direction) so as to approach each other as the elevating table 12 descends. The size of each cam portion 39 is set so that the slide mold 40 starts moving after the metal plate 100 is sandwiched between the punch 32 and the processing die 22.

As shown in FIG. 1, the pair of slide molds 40 are provided on the lower mold 20. As shown in FIG. 6, when the metal plate 100 is pressed toward the U-shaped recess 23 by the punch 32, a pair of vertical wall portions 101 extending in the vertical direction are formed on the metal plate 100. Each slide die 40 is a die that presses the standing wall portion 101 from the left-right direction.

The slide type 40 on the left side is slidable to the right side, and is configured to be urged to the left side by an urging device (not shown).

The slide type 40 on the left side has a slide type main body 41 and a curved forming portion 42 provided in a lower right portion of the slide type main body 41. As shown in FIG. 7, the bending forming portion 42 is a portion that actually presses the standing wall portion 101 from the left side, and forms a curved tip bending portion 103 on the right side at the tip portion 101a of the standing wall portion 101. The curved forming portion 42 has a curved concave surface portion 42a that is recessed so as to correspond to the shape of the upper surface portion 35c of the pressing portion 35. The curvature of the curved concave surface portion 42a is substantially the same as the curvature of the curved bottom surface portion 23b of the processing die 22.

On the upper left surface of the slide type 40 on the left side, an engaging surface 43 formed so as to extend along the cam surface 39a of the cam portion 39 on the left side is formed. Specifically, the engaging surface 43 is inclined upward to the right. When the elevating table 12 is lowered while the cam surface 39a of the left cam portion 39 and the engaging surface 43 are engaged, a force in the right direction acts on the slide mold 40 on the left side. The slide mold 40 moves to the right by this force in the right direction. Then, when the curved forming portion 42 comes into contact with the standing wall portion 101 of the metal plate 100, the standing wall portion 101 is pressed against the punch 32 by the force in the right direction to press the standing wall portion 101.

Since the configuration of the slide type 40 on the right side is symmetrical with that of the slide type 40 on the left side, detailed description thereof will be omitted. Regarding the operation of the slide type 40 on the right side, when the lifting platform 12 is lowered while the cam surface 39a of the cam portion 39 on the right side and the engaging surface 43 of the slide type on the right side are engaged, the slide type 40 on the right side is operated. A force in the left direction acts on. The slide mold 40 moves to the left by this force in the left direction. Then, when the curved forming portion 42 comes into contact with the standing wall portion 101 of the metal plate 100, the standing wall portion 101 is pressed against the punch 32 by the force in the left direction to press the standing wall portion 101.

<O bending device>
As shown in FIG. 3, the O-bending device 50 is configured symmetrically. The O-bending device 50 has a base 51 installed on the floor surface F, and an elevating base 52 which is arranged so as to be able to move up and down on the upper side of the base 51 facing the base 51. The first molding die 70 is fixed on the base 51, while the second molding die 80 is fixed on the elevating table 52.

The first molding die 70 has a first molding die main body 71 and a lower die 72 provided at the center of the first molding die main body 71 in the left-right direction.

Cam portions 73 extending upward toward the upper side are provided at both left and right end portions of the first molding mold main body 71 in the left-right direction. The cam surface 73a of the left cam portion 73 is inclined downward toward the right side. The cam surface 73a of the cam portion 73 on the right side is inclined downward toward the left side.

The lower die 72 has a semicircular recess 72a that is recessed from the upper side to the lower side in a semicircular shape.

The second molding die 80 has a second molding die main body 81 and a pair of split dies 90 provided so as to be slidable in the left-right direction with respect to the second molding die main body 81.

The second mold main body 81 has end side stopper portions 82 extending downward at both side end portions in the left-right direction. Further, the second molding die main body 81 has a central protruding portion 83 protruding downward at the center in the left-right direction. As shown in FIG. 3, the central projecting portion 83 projects below each end side stopper portion 82. As will be described in detail later, each end-side stopper 82 moves the split molds 90 so that the split molds 90 do not move excessively when the pair of split molds 90 move in the left-right direction so as to separate from each other. It is a part to limit. Further, the central protrusion 83 is a portion for restricting the movement of each split die 90 so that the upper dies 92 of the split die 90, which will be described later, come into contact with each other at an appropriate position.

The split mold 90 on the left side is slidable to the right side and is configured to be urged to the left side by an urging device (not shown). The left side split mold 90 is restricted from moving to the left side by the left end side stopper portion 82. The split mold 90 on the left side has a split mold main body 91 and an upper die 92 provided in the lower right portion of the split mold main body 91.

The split mold body 91 on the left side has an engaging surface 91a that engages with the cam surface 73a of the cam portion 73 on the left side in the lower left portion. When the elevating table 52 is lowered while the cam surface 73a of the left cam portion 73 and the engaging surface 91a are engaged, a force in the right direction acts on the split mold 90 on the left side. Due to this force in the right direction, the split mold 90 on the left side moves to the right.

The upper die 92 on the left side has an arcuate recess 92a recessed in a quarter circle. As shown in FIG. 11, the arcuate recess 92a is configured to form one circular shape in cooperation with the semicircular recess 72a of the lower die 72.

Since the configuration of the split mold 90 on the right side is symmetrical with that of the split mold 90 on the left side, detailed description thereof will be omitted. Regarding the operation of the split mold 90 on the right side, when the lift 52 is lowered while the cam surface 73a of the cam portion 73 on the right side and the engaging surface 91a of the split mold 90 on the right side are engaged, the split mold on the right side is operated. A leftward force acts on 90. Due to this leftward force, the split mold 90 on the right side moves to the left.

<Molding method of metal tube>
Next, a method of molding the metal tube P from the metal plate 100 by the metal tube forming apparatus 1 will be described. Since FIGS. 9 to 11 are shown by enlarging the entire apparatus in order to make the drawings easier to see, the total length of the metal plate 100 is longer in FIGS. 9 to 11 than in FIGS. 4 to 8. It looks like it has become.

First, as shown in FIG. 4, the metal plate 100 is carried between the lower mold 20 and the upper mold 30 in the mold-opened state. The metal plate 100 is placed on the lower mold 20 so that the central portion in the left-right direction is located on the U-shaped recess 23. At this time, each slide type 40 is in a state of being positioned at the initial position. Further, the counter punch 24 is in a state of being projected upward from the curved bottom surface portion 23b of the U-shaped recess 23 by the lower air cylinder 25.

Next, the elevating table 12 is lowered from the state of FIG. 4, and as shown in FIG. 5, the metal plate 100 is pressed toward the U-shaped recess 23 by the pressing portion 35 of the punch 32. The central portion of the metal plate 100 is sandwiched between the pressing portion 35 and the counter punch 24. The left side portion and the right side portion of the metal plate 100 receive an upward repulsive load from the edge portion of the processing die 22, and are bent upward so as to approach the punch 32. The counter punch 24 is pushed downward by the pressing portion 35 and moves downward against the urging force of the lower air cylinder 25.

Next, the elevating table 12 is lowered from the state of FIG. 5, and as shown in FIG. 6, the metal plate 100 is formed by the pressing portion 35 of the punch 32 and the processing die 22 (strictly speaking, the processing die 22 and the counter punch 24). Put it in a sandwiched state. As a result, the metal plate 100 is formed with a pair of standing wall portions 101 that face each other on the left and right and extend in the vertical direction, and a bottom wall portion 102 that connects and curves the lower end portions of each standing wall portion. The tip portion 101a of each standing wall portion 101 is in a state of protruding upward from the processing die 22. At this time, the slide mold 40 and the cam portion 39 of the upper mold 30 are not yet in contact with each other. That is, each slide type 40 has not yet moved in the horizontal direction (horizontal direction). This is possible by adjusting the size of each cam portion 39.

Next, the elevating table 12 is lowered from the state shown in FIG. 6, and the slide molds 40 are pressed by the cam portions 39 of the upper mold 30 so that the slide molds 40 are brought closer to each other in the horizontal direction (horizontal direction). ). Then, as shown in FIG. 7, the curved forming portion 42 of each slide type 40 presses the tip portion 101a of each standing wall portion 101 toward the upper surface portion 35c of the pressing portion 35, respectively. As a result, the tip end portion 101a of each standing wall portion 101 is sandwiched between the upper surface portion 35c and the curved concave surface portion 42a of each curvature forming portion 42, and is bent along each upper surface portion 35c. As a result, the tip curved portion 103 curved so as to approach each other is formed at the tip portion 101a of each standing wall portion 101. Specifically, the left standing wall portion 101 is formed with a tip curved portion 103 curved toward the right side, while the right standing wall portion 101 is formed with a tip curved portion 103 curved toward the left side. To. The curvature of each tip curved portion 103 is substantially the same as the curvature of the bottom wall portion 102. As a result, the metal plate 100 is processed into the preprocessed product 150. When the curvature of the tip curved portion 103 and the curvature of the bottom wall portion 102 are compared, substantially the same is a range in which the curvatures are the same or slightly smaller.

Subsequently, the elevating table 12 is raised from the state shown in FIG. 7 to release the upper mold 30. When the upper mold 30 rises, the slide molds 40 move in a direction away from each other. At this time, the standing wall portions 101 of the pre-processed product 150 move apart from each other by the springback. As a result, as shown in FIG. 8, the U-shaped opening of the preprocessed product 150 is opened, and the pressing portion 35 of the punch 32 can be released from the mold. Then, after raising the upper mold 30 to the top dead center, the preprocessed product 150 is taken out from the lower mold 20. The slide type 40 is restricted from moving in the left-right direction by each stopper portion 26, and returns to the initial position to stand by.

With the above, the U bending process is completed. After the U-bending process is completed, the pre-processed product 150 is subjected to the O-bending process by the O-bending device 50.

First, as shown in FIG. 9, the preprocessed product 150 is set on the lower die 72 of the first molding die 70. The pre-processed product 150 is set so that the bottom wall portion 102 is housed in the lower die 72 and the U-shaped opening faces upward.

Next, the lift 52 is lowered from the state shown in FIG. As a result, as shown in FIG. 10, the left and right split molds 90 receive a force in the left-right direction by each cam portion 73 of the first molding mold 70, move downward, and move in a direction approaching each other. .. At this time, the arcuate recess 92a of the upper die 92 in each split mold 90 and the curved surface of each tip curved portion 103 come into contact with each other. As a result, each split mold 90 presses the tip curved portion 103 of the pre-processed product 150 downward and in a direction approaching each other. Then, as shown in FIG. 10, when the upper dies 92 of each split die 90 come into contact with each other, the U-shaped opening of the pre-processed product 150 becomes narrow. Further, as shown in FIG. 10, when the upper dies 92 of the split molds 90 come into contact with each other, the arcuate recesses 92a of the upper dies 92 cooperate to form one semicircular recess. As a result, when the mold is matched with the lower die 72, a circular mold having a high degree of roundness is formed. As shown in FIG. 10, at the timing when the upper dies 92 come into contact with each other, a gap having a predetermined length is formed between the upper dies 92 and the lower dies 72.

Next, the lift 52 is further lowered from the state shown in FIG. As a result, as shown in FIG. 11, the pre-processed product 150 is pressed against the arcuate recess 92a of each upper die 92 and the semicircular recess 72a of the lower die 72, and is bent and deformed in an O shape. At this time, each split mold 90 can be moved straight downward without being displaced in the left-right direction by being guided by the central protrusion 83. After that, the elevating table 52 is raised to release the second molding die 80 including each split die 90. This completes the O-bending process.

As described above, the metal tube P is formed from the metal plate 100. After the metal pipe P is formed, the butt portion is welded by a welding device (not shown) to complete the metal pipe P.

As described above, in the present embodiment, the pre-processed product 150 is formed from the metal plate 100 by the U-bending device 10, so that the tip curved portion 103 is formed on the tip portion 101a of each standing wall portion 101 of the pre-processed product 150. To do. As a result, when the O-bending device 50 performs the O-bending process, the edge portion of each tip portion 101a does not abut on the upper die 92, but the curved surface of the tip bending portion 103 abuts on the upper die 92. As a result, the upper die 92 is less likely to be scraped off by each tip portion 101a of the pre-processed product 150, and the mold of the O-bending device 50 (particularly, the upper side of the split die 90) when the pre-processed product 150 is machined in an annular shape. The galling wear of the die 92) can be suppressed.

In the above-described embodiment, the upper die 92 is divided into left and right so as to come into contact with the tip curved portion 103 of the pre-processed product 150 while moving diagonally downward. However, the upper die 92 is not divided into left and right, and the upper die simply has a semicircular recess that is recessed on the upper side, and is configured to come into contact with the preprocessed product 150 while moving downward. Even if there is, the above-mentioned effect can be obtained. That is, even if the upper die has the above configuration, the curved surface of the tip curved portion 103 can be brought into contact with the semicircular recess of the upper die, so that the preprocessed product 150 is pressed by the upper die. At that time, it is possible to suppress the occurrence of galling wear on the upper die.

Therefore, in the present embodiment, the U-bending device 10 of the metal tube forming device 1 is arranged so as to be able to move up and down on the base 11 installed on the floor surface F and on the upper side of the base 11 facing the base 11. The lower mold 20 which is fixed on the base 11 and has a U-shaped concave portion 23 which is recessed on the lower side and on which the metal plate 100 is placed, and the lower mold 20 which is fixed on the base 11 and lower. An upper mold 30 having a punch 32 for pressing the metal plate 100 placed on the mold 20 toward the U-shaped recess 23, and a metal plate 100 provided on the lower mold 20 by the upper mold 30. With respect to a pair of standing wall portions 101 extending in the vertical direction formed on the metal plate 100 by being pressed toward the metal plate 100, the tip portion curved so as to approach the tip portion 101a of each standing wall portion 101. A pair of curved forming portions 42 for forming the curved portions 103 are provided. As a result, when the metal plate 100 is U-bent, the tip curved portion 103 is formed at the tip portion 101a of each standing wall portion 101. Therefore, when the O-bending device 50 processes the ring into an annular shape, the upper die 92 of the O-bending device 50 can be brought into contact with the curved surface of each tip bending portion 103. As a result, it is possible to suppress galling wear of the upper die 92 of the O-bending device 50 when the U-shaped bent metal plate 100 is processed into an annular shape. Further, since it is not necessary to excessively divide the upper die 92 of the O-bending device 50, it becomes easy to increase the roundness of the formed metal tube P. Further, since the tip curved portion 103 can be formed during the U bending process without separately preparing a step for forming the tip curved portion 103, the manufacturing cost can be suppressed.

Further, in the present embodiment, the punch 32 has a pressing portion 35 that actually enters the U-shaped recess 23 and presses the metal plate 100, and the pressing portion 35 has an outer edge shape corresponding to the U-shaped recess 23. A pair of lower surface portions 35a, a pair of side surface portions 35b extending straight upward from a pair of upper end portions of the lower surface portion 35a, and a pair of upper surfaces curved so as to approach each other from the upper end portion of each side surface portion 35b toward the upper side. Each tip curved portion 103 is formed by bending the tip portion 101a of the standing wall portion 101 along the upper surface portion 35c by the curved forming portion 42 having the portion 35c. This makes it easier to make the shape of each tip curved portion 103 more appropriate. As a result, galling wear of the upper die 92 of the O-bending device 50 can be suppressed more effectively.

In particular, in the present embodiment, each curved forming portion 42 has a curved concave surface portion 42a that is recessed so as to correspond to the shape of each upper surface portion 35c, and the upper surface portion 35c and the curved concave surface portion 42a form a vertical wall portion 101. Each bending portion 103 is formed by pressing each standing wall portion 101 from the side with each bending forming portion 42 so as to sandwich the tip portion 101a. As a result, it becomes easier to make the shape of each tip curved portion 103 more appropriate, and it becomes easier to maintain the shape of each tip curved portion 103. As a result, galling wear of the upper die 92 of the O-bending device 50 can be suppressed more effectively.

Further, in the present embodiment, the upper die 30 is provided with a cam portion 39 that moves the curved forming portions 42 in the horizontal direction so as to approach each other as the elevating table 12 descends. Since the curved forming portions 42 can be brought close to each other as the elevating table 12 descends, it is not necessary to separately prepare a drive source for moving the curved forming portions 42, and the cost can be reduced.

In particular, in the present embodiment, since the lower mold 20 is provided with the slide mold 40 having the curved forming portion 42 and the upper mold 30 is provided with each cam portion 39, the left and right sides of the curved forming portion 42 are not moved up and down. It can be moved horizontally in the direction. As a result, a force in the left-right direction can be efficiently applied to each standing wall portion 101, and each tip curved portion 103 can be easily formed.

Further, in the present embodiment, in each curved forming portion 42, the punch 32 enters the U-shaped recess 23, the metal plate 100 is sandwiched between the punch 32 and the processing die 22, and then the tip of each standing wall portion 101. The portion 101a is configured to be curved. As a result, the tip curved portion 103 is formed after each of the standing wall portion 101 and the bottom wall portion 102 is formed, so that the shape of the preprocessed product 150 can be made more appropriate. As a result, the roundness of the formed metal tube P can be improved.

Further, in the present embodiment, each bending forming portion 42 has a tip portion of each standing wall portion 101 so that the curvature of each tip bending portion 103 is substantially the same (same or slightly smaller) as the curvature of the bottom wall portion 102. It is configured to bend 101a. As a result, the mold of the O-bending device 50 can be brought into contact with the curved surface of each tip bending portion 103 more effectively. As a result, galling wear of the upper die 92 of the O-bending device 50 can be suppressed more effectively.

(Other embodiments)
The technique disclosed herein is not limited to the above-described embodiment, and can be substituted as long as it does not deviate from the gist of the claims.

For example, in the above-described embodiment, the bending forming portion 42 sandwiches the tip portion 101a of the standing wall portion 101 between the upper surface portion 35c of the pressing portion 35 in the punch 32 and the bending forming portion 42 having the curved concave surface portion 42a. By pressing the standing wall portion 101 from the side, the tip curved portion 103 was formed. Not limited to this, for example, the bending forming portion 42 is composed of a pressing roller, and the pressing roller presses the standing wall portion 101 toward the upper surface portion 35c of the pressing portion 35 to form the tip curved portion 103. It may be.

Further, in the above-described embodiment, the slide type 40 having the curved forming portion 42 is configured to move in the left-right direction by the cam portion 39. Not limited to this, a fluid cylinder for moving the slide type 40 in the left-right direction may be provided, and the curve forming portion 42 may be moved in the left-right direction together with the slide type 40 by the fluid cylinder. In this case, the fluid cylinder so as to allow the punch 32 to enter the U-shaped recess 23, sandwich the metal plate 100 between the punch 32 and the processing die 22, and then move the slide mold 40 toward the punch 32. It is preferable to provide a control device.

Further, in the above-described embodiment, the lower mold 20 is provided with the slide mold 40 having the curved forming portion 42, and the upper mold 30 is provided with the cam portion 39. Not limited to this, the lower mold 20 may be provided with the cam portion 39, and the upper mold 30 may be provided with the slide mold 40 having the curved forming portion 42.

Further, in the above-described embodiment, the columnar core is not used during the O-bending process, but the columnar core may be used. Thereby, the roundness of the metal tube P can be further improved.

The above embodiments are merely examples, and the scope of the present disclosure should not be construed in a limited manner. The scope of the present disclosure is defined by the scope of claims, and all modifications and changes belonging to the equivalent scope of the scope of claims are within the scope of the present disclosure.

The technique disclosed herein is a U-bending device that bends a metal plate into a U-shape, and a metal plate that is bent into a U-shape by the U-bending device is pressed from the U-shaped opening side by a mold to form an annular shape. It is useful as a metal tube forming apparatus having an annulus processing apparatus for processing.

1 Metal tube forming device 10 U bending device 11 Base 12 Lifting table 20 Lower type 23 U-shaped recess 30 Upper type 32 Punch 35 Pressing part 35a Lower surface part 35b Side surface part 35c Upper surface part 39 Cam part 42 Curved forming part 42a Curved concave surface Part 50 O bending device (annular processing device)
100 Metal plate 101 Standing wall 101a Tip 102 Bottom wall 103 Curved tip F Floor P Metal pipe

Claims (7)

A U-bending device that bends a metal plate into a U-shape, and an annular processing device that presses the metal plate bent into a U-shape by the U-bending device from the U-shaped opening side with a mold to process it into an annular shape. It is a metal tube forming apparatus having
The U bending device is
The base installed on the floor and
An elevating table that is arranged so as to be able to move up and down on the upper side of the base so as to face the base.
A lower mold that is fixed on the base, has a recessed recess on the lower side, and on which the metal plate is placed.
An upper mold having a punch fixed to the lift and pressing the metal plate placed on the lower mold toward the recess.
With respect to a pair of vertical wall portions extending in the vertical direction, which are provided on either the lower mold or the upper mold and are formed on the metal plate by pressing the metal plate toward the recess by the upper mold. A pair of curved forming portions that form curved tip curved portions that are curved so as to approach each other at the tip portions of the standing wall portions.
A metal tube forming apparatus comprising. In the metal tube molding apparatus according to claim 1,
The punch actually has a pressing portion that enters the recess and presses the metal plate.
The pressing part is
A lower surface having an outer edge shape corresponding to the recess,
A pair of side surfaces extending straight upward from the pair of upper end portions of the lower surface portion,
A pair of upper surface portions curved so as to approach each other from the upper end portion of each side surface portion toward the upper side.
Have,
A metal tube forming apparatus characterized in that each of the tip curved portions is formed by bending the tip portion of the standing wall portion along the upper surface portion by the curved forming portion. In the metal tube molding apparatus according to claim 2,
Each of the curved forming portions has a curved concave surface portion that is recessed so as to correspond to the shape of each of the upper surface portions.
The tip curved portion is formed by pressing each of the standing wall portions from the side with each of the curved forming portions so that the tip portion of the standing wall portion is sandwiched between the upper surface portion and the curved concave surface portion. A metal tube forming apparatus characterized in that. In the metal tube molding apparatus according to claim 3,
A metal characterized in that the other of the lower mold or the upper mold is provided with a cam portion that moves the curved forming portions in the horizontal direction so as to approach each other as the elevating table descends. Tube forming equipment. In the metal tube molding apparatus according to any one of claims 1 to 4.
Each of the curved forming portions is configured so that the punch enters the recess, sandwiches the metal plate between the punch and the lower mold, and then bends the tip portion of each of the standing wall portions. A metal tube forming apparatus characterized by. In the metal tube molding apparatus according to any one of claims 1 to 5.
In a metal plate bent into a U shape by the U-bending device, each end of each standing wall portion on the opposite side of the tip-curved portion is connected and the curved portion is used as a bottom wall portion.
Each of the curved forming portions is a metal characterized in that the tip portion of each of the standing wall portions is curved so that the curvature of the tip curved portion is substantially the same as the curvature of the bottom wall portion. Tube forming equipment. By a U-bending step of bending a metal plate into a U-shape, and a ring processing step of pressing the metal plate bent into a U-shape by the U-bending step from the U-shaped opening side with a mold to form an annular shape. It is a metal tube molding method for molding a metal tube.
The U bending step is
The mounting process of mounting the metal plate on a lower mold having a recessed recess on the lower side, and
A pressing step of pressing the metal plate placed on the lower mold toward the concave portion by an upper mold having a punch having a shape corresponding to the concave portion.
Tip processing that forms curved tip curved portions that are curved so as to approach each other at the tip portions of the standing wall portions that extend in the vertical direction and are formed on the metal plate by the pressing step. Process and
A metal tube molding method comprising.

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