JP2021062378A - Metallic plate machining device and metallic plate machining method - Google Patents

Abstract

To suppress galling abrasion of a die of a circular ring machining device, in machining a metallic plate into a circular ring shape by UO molding and enhance circularity of a metallic pipe to be molded as much as possible.SOLUTION: A metallic plate machining device comprises a C-bending device 10 that bends a metallic plate 100 in a C-shape before a U-bending device 20 performs U-bending machining to the plate. The C-bending device 10 has a first lower mold 13 having a first recessed part 14 recessed downward, on which the metallic plate 100 is placed, and a first upper mold 15 having a first punch 16 which presses the metallic plate 100 placed on the first lower mold 13 toward the first recessed part 14. A cross sectional shape of the first recessed part 14 has end-side bending portions 14a which is provided at both-side end parts in a width direction, for forming curve shapes at both end parts respectively in the width direction of the metallic plate 100; and a center bending portion 14b which is provided at a center in the width direction, for forming a curve shape at a center in the width direction of the metallic plate 100.SELECTED DRAWING: Figure 1

Description

The technology disclosed herein belongs to the technical field relating to the metal plate processing apparatus and the metal plate processing method.

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.

JP-A-2019-104025

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.

The technique disclosed here has been made in view of these points, and the purpose thereof is to grab the mold of the annular processing apparatus when processing a metal plate into an annular shape by UO molding. The purpose is to suppress wear and to make the roundness of the formed metal tube as high as possible.

In order to solve the above problems, the first aspect of the technique disclosed here is to bend a metal plate into a U shape and then press it from the U shape opening side with a mold to process the metal into an annular shape. When manufacturing a tube, the metal plate has a first recess that is recessed downward for a metal plate processing device that bends the metal plate into a C shape before bending the metal plate into a U shape. The first lower mold is provided with a first lower mold on which the metal plate is placed and a first upper mold having a first punch for pressing the metal plate placed on the first lower mold toward the first recess. The cross-sectional shape of the recess is provided at both side ends in the width direction, and is provided at both end portions of the metal plate in the width direction to form a curved shape, and is provided at the center in the width direction. It is characterized by having a central curved portion for forming a curved shape at the center in the width direction of the metal plate.

A second aspect of the technique disclosed herein is that, in the first aspect, in the cross-sectional shape of the first recess, the portions between the end side curved portions and the central curved portions are described above. It is characterized in that it is an inclined portion extending so as to connect the end side curved portion and the central curved portion.

A third aspect of the technique disclosed herein is that, in the second aspect, the U-bending device that bends the metal plate into a U-shape after bending the metal plate into a C-shape is recessed downward. A second lower mold having a second recess on which a metal plate bent in a C shape is placed and a metal plate placed on the second lower mold are pressed toward the second recess. The U-bending device has a second upper mold having a second punch, and after bending into a U-shape by the second punch, both end portions of the U-shaped metal plate are subjected to the second. It is characterized in that it is configured to be pressed by the upper mold.

A fourth aspect of the technique disclosed herein is that when a metal plate is bent into a U shape and then pressed from the U-shaped opening side by a mold to be processed into an annular shape, the metal tube is manufactured. For the metal plate processing method of bending the metal plate into a C shape before bending the metal plate into a U shape, a mounting step of placing the metal plate on a lower mold having a recessed recess on the lower side, and The pressing step includes a pressing step of pressing the metal plate placed on the lower mold toward the recess, and the pressing steps include both end portions in the width direction of the metal plate and the center in the width direction of the metal plate. It is characterized in that it is a step of forming each curved portion.

According to the first and fourth aspects of the technique disclosed herein, the C-bent metal plate has curved shapes at both side ends in the width direction and the center in the width direction. Since the metal plate has curved shapes at both end portions in the width direction, when the U-bending process is performed, each tip portion of the U-shaped metal plate is in a curved state. 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 tip portion. When the die of the ring processing apparatus comes into contact with the curved surface of each tip portion, it is suppressed that the die is scraped by the tip portion of the metal plate. 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 the metal plate has a curved shape in the center in the width direction, U-bending in the U-bending device can be smoothly performed. Further, by bending the center of the metal plate in the width direction in advance, it is possible to prevent the metal plate after U-bending from being deformed such as opening a U-shaped opening due to springback as much as possible. As a result, the shape stability of the metal plate after U-bending is improved, and the processing with the ring processing apparatus can be performed stably. As a result, the roundness of the formed metal tube can be improved.

According to the second aspect of the technique disclosed herein, by forming the shape having the inclined portion, the curvature of each end side curved portion and the central curved portion is compared with the case where the entire first concave portion is curved. Can be increased. As a result, when the metal plate is processed into an annular shape by the annular processing apparatus, the mold of the annular processing apparatus can be easily brought into contact with the curved surface of each tip portion. As a result, it is possible to more effectively suppress galling wear of the mold of the ring processing apparatus when the metal plate is processed into an annular shape by UO molding.

According to the third aspect of the technique disclosed herein, even if the curvature of the curved shape formed by the C bending device is lowered by springback or the like, the curvature of the curved shape is restored to some extent by the U bending device. Can be done. Further, the entire metal plate can be bent to some extent by the repulsive load of the second lower mold and the pressing force of the second upper mold. As a result, when the metal plate is processed into an annular shape by the annular processing apparatus, the mold of the annular processing apparatus can be easily brought into contact with the curved surface formed on the metal plate. Therefore, it is possible to more effectively suppress the galling wear of the mold of the ring processing apparatus when the metal plate is processed into an annular shape by UO molding.

FIG. 5 is a cross-sectional view of a C-bending device according to an exemplary embodiment, showing a state in which the first upper die is at the top dead center position. It is sectional drawing of the U bending apparatus, and shows the state in which the 2nd upper die is at the position of the top dead center. It is sectional drawing of the O bending apparatus, and shows the state in which the 3rd upper die is at the position of the top dead center. FIG. 5 is an operation diagram of the C bending device, showing a state in which a metal plate is pressed by a lower curved surface portion of the first punch. FIG. 5 is an operation diagram of the C bending device, showing a state in which a metal plate is pressed by a first punch and a first lower die from the state of FIG. It is sectional drawing which shows the 1st pre-processed article formed by the C bending apparatus. It is an operation diagram of the U bending apparatus, and shows the state which the 2nd punch and the 1st pre-processed article were in contact with each other. FIG. 5 is an operation diagram of the U-bending device, showing a state in which the first pre-processed product is pressed by the second punch from the state of FIG. 7. FIG. 5 is an operation diagram of the U-bending device, showing a state in which both end portions of the first pre-processed product are pressed by the second upper mold from the state of FIG. It is an operation diagram of the O bending apparatus, and shows the state in which the 2nd pre-processed product is placed on the 3rd lower mold. FIG. 5 is an operation diagram of the O-bending device, showing a state in which the cam portion of the third upper mold is in contact with the slide mold 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 apparatus 1 is a C bending apparatus 10 (metal plate processing apparatus) that bends a flat metal plate 100 into a C shape to obtain a first preprocessed product 150, and a U-shaped first preprocessed product 150. It has a U-bending device 20 that bends the second pre-processed product 151 to obtain a second pre-processed product 151, and an O-bending device 50 that processes the second pre-processed product 151 into an annular shape, particularly in an O-shaped cross section. FIG. 1 shows a C-bending device 10, FIG. 2 shows a U-bending device 20, and FIG. 3 shows an O-bending device 50. In the following description, the process of bending the metal plate 100 into a C shape is simply referred to as a C-bending process, and the process of bending the first pre-processed product 150 into a U-shape is simply referred to as a U-bending process. The process of bending the product 151 into an O shape is simply called the O-bending process. Further, the vertical direction and the horizontal direction used in the following description do not limit the directions 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 example, as a metal tube for a body part of an automobile or a portion of an automobile where high strength is required.

<C bending device>
As shown in FIG. 1, the C bending device 10 is configured symmetrically. The C-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 first lower mold 13 is fixed on the base 11, while the first upper mold 15 is fixed on the elevating base 12.

The first lower mold 13 has a first recess 14 that is recessed from the upper side to the lower side. As shown in FIG. 1, the cross-sectional shape of the first recess 14 has end-side curved portions 14a that are curved upward toward the outside in the width direction at both end portions in the width direction. Specifically, the left end side curved portion 14a is curved upward toward the left side, and the right end side curved portion 14a is curved upward toward the right side. Further, the first recess 14 has a central curved portion 14b curved in a U shape so as to open upward in the center in the width direction.

The portion of the first recess 14 between each end side curved portion 14a and the central curved portion 14b becomes a lower inclined portion 14c extending diagonally so as to connect the end side curved portion 14a and the central curved portion 14b, respectively. ing. Specifically, the right end of the left end side curved portion 14a and the left end of the central curved portion 14b are continuously connected by the lower inclined portion 14c. Further, the left end of the right end side curved portion 14a and the right end of the central curved portion 14b are continuously connected by the lower inclined portion 14c. The lower inclined portion 14c is an inclined plane extending diagonally and straight.

The corners between the upper side surface of the first lower mold 13 and the curved portions 14a on each end side are each R-chamfered.

The first upper mold 15 has a first punch 16. As shown in FIG. 1, the first punch 16 has a substantially pentagonal shape so as to correspond to the first recess 14. Specifically, the first punch 16 has a pair of side curved surface portions 16a corresponding to the pair of end side curved portions 14a and a lower curved surface portion 16b corresponding to the central curved portion 14b. Between each side curved surface portion 16a and the lower curved surface portion 16b, an upper inclined portion 16c extending straight is formed so as to correspond to the lower inclined portion 14c.

<U bending device>
As shown in FIG. 2, the U-bending device 20 is configured symmetrically. The U-bending device 20 has a base 21 installed on the floor surface F, and an elevating base 22 arranged so as to be able to move up and down on the upper side of the base 21 facing the base 21. The second lower mold 23 is fixed on the base 21, while the second upper mold 25 is fixed on the elevating base 22.

The second lower mold 23 has a second recess 24 that is recessed downward in a U shape at the center in the width direction. The second recess 24 has a shape in which the U-shaped opening gradually expands toward the upper side. The corners between the upper end of the second recess 24 and the upper surface of the second lower mold 23 are each R-chamfered.

The second upper mold 25 has a second upper mold main body 26 and a second punch 30 provided at the center of the second upper mold main body 26 in the left-right direction.

The second upper mold main body 26 has an upper concave portion 27 provided at the center in the left-right direction and recessed toward the upper side. The upper recess 27 is a horizontal portion 28 whose upper end extends horizontally. Both the left side and the right side of the upper concave portion 27 are formed with an inclined curved surface portion 29 that is curved in an S shape and is inclined at an angle. Specifically, the inclined curved surface portion 29 on the left side is curved so as to be dented upward and then bulged downward from the left end of the horizontal portion 28 toward the diagonally lower left side. The inclined curved surface portion 29 on the right side is curved so as to dent upward and then bulge downward from the right end of the horizontal portion 28 diagonally downward to the right, in symmetry with the inclined curved surface portion 29 on the left side. ing.

The second punch 30 includes a second punch main body 31 extending in the vertical direction, a pair of side pressing portions 32 for pressing the first preprocessed product 150 (see FIG. 6 and the like) against the side wall of the second recess 24, and each of them. It has a cam driver 33 that moves the side pressing portion 32 in the left-right direction.

The second punch main body 31 has a rod portion 31a extending in the vertical direction and a pressing portion 31b provided at the lower end portion of the rod portion 31a to press the first preprocessed product 150. Although detailed illustration is omitted, the rod portion 31a is connected to an air cylinder provided in the second upper mold 25. The rod portion 31a is urged downward by the air cylinder, and when a predetermined amount or more of force is applied upward, the rod portion 31a moves relative to the second upper mold 25 against the urging force of the air cylinder. It has become like. As shown in FIG. 2, the pressing portion 31b is wider in the left-right direction than the rod portion 31a, and the lower surface is a curved surface. As shown in FIG. 2, the curvature of the curved surface of the pressing portion 31b when cut along the axial center of the rod portion 31a is equal to the curvature of the lower end portion in the cross section of the second recess 24. The upper surface of the pressing portion 31b extends horizontally to the left and right.

Each side pressing portion 32 has an engaging surface 32a pressed by the cam driver 33. Each side pressing portion 32 moves left and right so as to be separated from each other by pressing each engaging surface 32a downward by the cam driver 33, and presses the first pre-processed product 150. Although not shown, the side pressing portions 32 are urged in a direction approaching each other by a spring or the like. As will be described in detail later, the side pressing portion 32 is the first pre-processed product after the first pre-processed product 150 is pressed toward the second recess 24 by the second punch body 31 and bent into a U shape. The 150 is pressed toward the side wall of the second recess 24.

The cam driver 33 has a tapered portion 33a at the lower end portion that presses the engaging surface 32a of the side pressing portion 32. The cam driver 33 is urged upward by a spring or the like. As will be described in detail later, the cam driver 33 moves downward against the urging force when the second upper mold 25 is lowered and pressed against the horizontal portion 28 of the upper concave portion 27.

<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 third lower mold 53 is fixed on the base 51, while the third upper mold 56 is fixed on the elevating base 52. Further, on the third lower mold 53, a pair of slide molds 60 for pressing the second preprocessed product 151 from the side (from the left-right direction) are provided.

The third lower mold 53 has a lower arcuate recess 54. The lower arcuate recess 54 has an arcuate shape that opens upward. The corners between each upper end of the lower arcuate recess 54 and the upper surface of the third lower mold 53 are each R-chamfered.

The third lower mold 53 has stopper portions 55 extending upward at both end portions in the left-right direction. The stopper portion 55 is a portion for restricting the movement of the slide molds 60 so that the slide molds 60 do not move excessively when the pair of slide molds 60 move in the left-right direction so as to be separated from each other. ..

The third lower mold 53 has an engaging groove portion 53a recessed downward at each position between each stopper portion 55 and the lower arcuate concave portion 54. The engaging groove portion 53a is a portion where the lower end portion of the cam portion 70, which will be described later, of the third upper mold 56 is engaged.

The third upper mold 56 has an upper arcuate recess 57 at the center in the left-right direction. The upper arcuate recess 57 has an arcuate shape that opens downward.

The third upper mold 56 has a pair of cam portions 70 provided on the left side and the right side of the upper arcuate recess 57, respectively. Each cam portion 70 has an inner cam surface 71 on the upper arcuate recess 57 side and an outer cam surface 72 provided on a portion opposite to the upper arcuate recess 57. The cam surfaces 71 and 72 of the left cam portion 70 are inclined downward toward the left side. The cam surfaces 71 and 72 of the cam portion 70 on the right side are inclined downward toward the right side. The inclination angles of the inner and outer cam surfaces 71 and 72 are the same. Further, the cam portion 70 has an inclined surface 73 on the upper arcuate recess 57 side and above the inner cam surface 71, respectively. As shown in FIG. 3, the inclination angle of the inclined surface 73 is the same as the inclination angle of the inner and outer cam surfaces 71 and 72. As will be described in detail later, the cam portion 70 is a cam portion 70 for operating the slide type 60.

Each slide type 60 has an engaging portion 61 into which the cam portion 70 enters, and an arc-shaped pressing portion 62 for pressing the second preprocessed product 151.

The engaging portion 61 has a first engaging surface 61a that engages with the inner cam surface 71 when the elevating table 52 descends, and an outer side when the elevating table 52 rises after the cam portion 70 enters the engaging portion 61. It has a second engaging surface 61b that engages with the cam surface 72. Taking the slide type 60 on the left side as an example, when the lift 52 is lowered while the first engaging surface 61a of the slide type 60 on the left side and the inner cam surface 71 of the cam portion 70 are engaged, the slide type 60 on the left side is used. A rightward force acts on 60. As a result, the slide mold 60 on the left side moves so as to approach the slide mold 60 on the right side. Further, when the elevating table 52 is raised while the cam portion 70 is inserted into the engaging portion 61 of the slide type 60 on the left side (see FIG. 12), the second engaging surface 61b and the cam portion 70 of the slide type 60 on the left side are raised. Engages with the outer cam surface 72 of. When the lift 52 is further raised from this state, a leftward force acts on the slide type 60 on the left side. As a result, the slide mold 60 on the left side moves away from the slide mold 60 on the right side. That is, the slide mold 60 can be moved in the left-right direction only by the vertical movement of the third upper mold 56. The slide type 60 on the right side moves symmetrically with the slide type 60 on the left side.

The arc-shaped pressing portion 62 has an arc shape that continuously connects the lower arc-shaped recess 54 and the upper arc-shaped recess 57 to form one circle. Specifically, the arc-shaped pressing portion 62 on the left side has a concave arc shape on the left side, and the arc-shaped pressing portion 62 on the right side has a concave arc shape on the right side. Each arc-shaped pressing portion 62 is configured to be continuous with the lower arc-shaped recess 54 and the upper arc-shaped recess 57 when the elevating table 52 is lowered until the lower end portion of the cam portion 70 enters the engaging groove portion 53a. ing.

<Molding method of metal tube>
Next, a method of forming the metal tube P from the metal plate 100 by the metal tube forming apparatus 1 will be described with reference to FIGS. 4 to 12. Since the scale of each drawing is appropriately adjusted in order to make the drawings easier to see, the sizes of the first pre-processed product 150 and the second pre-processed product 151 may not match.

First, as shown in FIG. 4, the metal plate 100 is placed on the first lower mold 13, and the metal plate 100 is pressed toward the first recess 14 by the first punch 16 of the C bending device 10.

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 by the first punch 16, and the metal plate 100 is pressed by the first punch 16 and the first recess 14. Hold. As a result, curved portions are formed at the center and both ends of the metal plate 100 in the width direction, respectively. As a result, the first preprocessed product 150 as shown in FIG. 6 is formed.

As shown in FIG. 6, the first pre-processed product 150 has a pair of end-side curved portions 150a and a central curved portion 150b. The end-side curved portion 150a and the central curved portion 150b are continuously connected by a straight-line portion 150c, respectively.

With the above, the C bending process is completed. After the C-bending process is completed, the U-bending device 20 performs the U-bending process on the first pre-processed product 150.

In the U-bending process, first, as shown in FIG. 7, the first pre-processed product 150 is set in the second recess 24 of the second lower mold 23. The first pre-processed product 150 is set so that the central curved portion 150b is housed in the second recess 24 and the U-shaped opening faces upward.

Next, the elevating table 22 is lowered from the state of FIG. 7, and as shown in FIG. 8, the first pre-processed product 150 is pressed toward the second recess 24 by the pressing portion 31b of the second punch 30. To do. As a result, the central curved portion 150b enters the second concave portion 24, and each end side curved portion 150a and each straight portion 150c are mutated upward so as to close the U-shaped opening by the reaction force from the second lower mold 23.

When the lift 22 is further lowered from the state of FIG. 8, as shown in FIG. 9, the engaging surface 32a of each side pressing portion 32 is pressed by the cam driver 33, and the side pressing portions 32 are separated from each other. Move to. As a result, each straight portion 150c of the first pre-processed product 150 is pressed against the second recess 24. As a result, the portion near the central curved portion 150b in each straight portion 150c is bent. Further, as shown in FIG. 9, after the first pre-processed product 150 is bent into a U shape, each end side curved portion 150a presses against the horizontal portion 28 and each inclined curved surface portion 29 of the second upper mold 25. Will be done. As a result, each straight portion 150c bends. As a result, from the first pre-processed product 150, a second pre-processed product 151 bent into a U shape so as to form a substantially elliptical outer shape is formed.

With the above, the U bending process is completed. After the U-bending process is completed, the O-bending device 50 performs the O-bending process on the second pre-processed product 151.

First, as shown in FIG. 10, the second pre-processed product 151 is set in the lower arcuate recess 54 of the third lower mold 53. The second pre-processed product 151 is set so that the U-shaped opening faces upward. At this time, each slide type 60 is in contact with the stopper portion 55.

Next, the lift 52 is lowered from the state shown in FIG. As a result, as shown in FIG. 11, the upper arcuate concave portion 57 and the end side curved portion 150a come into contact with each other. At this time, the upper arcuate concave portion 57 comes into contact with the curved surface of the end side curved portion 150a.

Further, as shown in FIG. 11, each first engaging surface 61a of the left and right slide type 60 and the inner cam surface 71 of each cam portion 70 are engaged with each other. At this time, as shown in FIG. 11, the second engaging surface 61b and the outer cam surface 72 are in a state of being obliquely continuous. When the elevating table 52 is further lowered from the state shown in FIG. 11, each slide type 60 receives a force in the left-right direction by each cam portion 70 of the third upper type 56 and moves in a direction approaching each other. As a result, the second pre-processed product 151 receives a force in the left-right direction from each slide type 60 so as to close the U-shaped opening. At this time, as a result of the second pre-processed product 151 being deformed by the force from the slide mold 60, a gap may be formed between the second pre-processed product 151 and the upper arcuate recess 57.

Then, as shown in FIG. 12, the elevating table 52 is further lowered until the lower end portion of each cam portion 70 and the engaging groove portion 53a of the third lower mold 53 are engaged. As a result, as shown in FIG. 12, the second pre-processed product 151 is pressed by the lower arc-shaped recess 54, the upper arc-shaped recess 57, and the arc-shaped pressing portion 62 of each slide type 60, and has an O-shape. It is bent and deformed.

After that, the lift 52 is raised to release the slide mold 60 and the third upper mold 56. At this time, each of the second engaging surfaces 61b of the left and right slide molds 60 presses the outer cam surface 72 of each cam portion 70. As a result, each slide type 60 moves in a direction away from each other. As a result, the release of the third upper mold 56 and each slide mold 60 is completed at the same time. Then, when the third lower mold 53 is released, the O-bending process is completed and the metal tube P is formed.

After the metal tube P is formed, the abutting portion between the tips is welded by a welding device (not shown) to complete the metal tube P.

As described above, in the present embodiment, by molding the first pre-processed product 150 from the metal plate 100 by the C bending device 10, the end-side curved portion 150a can be formed at the time of molding the second pre-processed product 151. it can. As a result, when O-bending is performed by the O-bending device 50, the edge portion of each tip of the second pre-processed product 151 does not abut on the upper arcuate recess 57, and the curved surface of the end-side curved portion 150a has an upper arcuate shape. It abuts on the recess 57. As a result, the third upper die 56 is less likely to be scraped off by each tip of the second preprocessed product 151, and the die of the O bending device 50 (particularly, the first die) when the second preprocessed product 151 is machined in an annular shape. 3 It is possible to suppress galling wear of the upper die 56).

In the above-described embodiment, the upper arcuate recess 57 is brought into contact with the second pre-processed product 151 while closing the U-shaped opening of the second pre-processed product 151 with a pair of left and right slide molds 60. However, even if there is no slide type 60, the above-mentioned effect can be obtained. That is, even when the slide mold 60 is not provided, the curved surface of the end-side curved portion 150a can be brought into contact with the upper arcuate concave portion of the third upper mold 56. Therefore, when the second pre-processed product 151 is pressed by the upper arcuate concave portion, it is possible to prevent the third upper mold 56 from being gnawed and worn.

Therefore, in the present embodiment, the C-bending device 10 for bending the metal plate 100 into a C shape before the U-bending process is performed by the U-bending device 20, and the C-bending device 10 is the first recess 14 recessed downward. First having a first lower mold 13 on which the metal plate 100 is placed, and a first punch 16 for pressing the metal plate 100 placed on the first lower mold 13 toward the first recess 14. The upper mold 15 and the cross-sectional shape of the first recess 14 are provided at both side ends in the width direction, respectively, and end-side curved portions 150a are formed at both ends in the width direction of the metal plate 100. It has an end side curved portion 14a and a central curved portion 14b provided at the center in the width direction and for forming a central curved portion 150b at the center in the width direction of the metal plate 100. As a result, the metal plate 100 (first preprocessed product 150) has the end-side curved portion 150a, so that when U-bending is performed, each tip portion of the U-shaped metal plate 100 (second preprocessed product 151) is formed. Are in a curved state. As a result, when the O-bending device 50 processes the ring into an annular shape, the third upper die 56 of the O-bending device 50 can be brought into contact with the curved surface of each tip portion. When the third upper mold 56 of the O bending device 50 comes into contact with the curved surface of each tip portion, it is possible to prevent the third upper mold from being scraped by the tip portion of the metal plate 100. As a result, it is possible to suppress galling wear of the mold of the O-bending device 50 when the metal plate 100 is processed into an annular shape by UO molding.

Further, since the metal plate 100 has the central curved portion 150b at the center in the width direction, the U-bending in the U-bending device 20 can be smoothly performed. Further, by bending the center of the metal plate 100 in the width direction in advance, it is possible to prevent the metal plate 100 after U bending from being deformed such as opening a U-shaped opening due to springback as much as possible. .. As a result, the shape stability of the metal plate 100 (second pre-processed product 151) after U-bending is improved, and machining with the O-bending device 50 can be performed stably. As a result, the roundness of the formed metal tube P can be improved.

Further, in the present embodiment, in the cross-sectional shape of the first concave portion 14, the portion between each end side curved portion 14a and the central curved portion 14b connects the end side curved portion 14a and the central curved portion 14b, respectively. It is a lower inclined portion 14c extending so as to. By forming the shape having the lower inclined portion 14c, the curvature of each end side curved portion 14a and the central curved portion 14b can be increased as compared with the case where the entire first concave portion 14 is curved. As a result, when the metal plate 100 is processed into an annular shape by the O-bending device 50, the third upper die 56 of the O-bending device 50 can be easily brought into contact with the curved surface of each tip portion. As a result, it is possible to more effectively suppress galling wear of the mold of the O-bending device 50 when the metal plate 100 is processed into an annular shape by UO molding.

Further, in the present embodiment, the U bending device 20 has a second recess 24 recessed on the lower side, and the C-shaped metal plate 100 (first preprocessed product 150) processed by the C bending device 10 is formed. It has a second lower mold 23 on which it is placed, and a second upper mold 25 having a second punch 30 that presses the metal plate 100 placed on the second lower mold 23 toward the second recess 24. Further, the U-bending device 20 is configured to bend the U-shaped metal plate 100 into a U-shape by the second punch 30 and then press both side ends of the U-shaped metal plate 100 by the second upper mold 25. As a result, even if the curvature of the end-side bending portion 150a formed by the C-bending device 10 is lowered due to springback or the like, the curvature of the end-side bending portion 150a can be returned to some extent by the U-bending device. Further, the entire metal plate 100 (first preprocessed product 150) can be bent to some extent by the repulsive load of the second lower mold 23 and the pressing force of the second upper mold 25. As a result, when the metal plate 100 is processed into an annular shape by the O-bending device 50, the third upper mold 56 of the O-bending device 50 can be easily brought into contact with the curved surface formed on the metal plate 100. Therefore, it is possible to more effectively suppress the galling wear of the mold of the O-bending device 50 when the metal plate 100 is processed into an annular shape by UO molding.

(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, in the cross-sectional shape of the first concave portion 14, the portion between each end side curved portion 14a and the central curved portion 14b has the end side curved portion 14a and the central curved portion 14b, respectively. It was a lower inclined portion 14c extending so as to connect. Not limited to this, if the end-side curved portion 150a and the central curved portion 150b are formed in the first pre-processed product 150, the portion between each end-side curved portion 14a and the central curved portion 14b is curved. You may be.

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 here is that when a metal plate is bent into a U shape and then pressed from the U-shaped opening side by a mold to be processed into an annular shape to manufacture a metal tube, the metal plate is U-shaped. It is useful as a metal plate processing device that bends the metal plate into a C shape before bending it into a shape.

10 C bending device (metal plate processing device)
13 First lower mold
14 First recess
14a End side curved part
14b Central bend
14c Lower slope
15 First upper mold
16 1st punch
20 U bending device
23 Second lower mold
24 Second recess
25 Second upper mold
30 Second punch
50 O bending device 100 metal plate
150 1st pre-processed product (C-shaped metal plate)
151 Second pre-processed product (metal plate bent into a U shape)
P metal tube

Claims (4)

When a metal plate is bent into a U shape and then pressed from the U-shaped opening side by a mold to be processed into an annular shape to manufacture a metal tube, the metal plate is processed before being bent into a U shape. Is a metal plate processing device that bends in a C shape.
A first lower mold having a recessed first recess on the lower side and on which the metal plate is placed,
A first upper mold having a first punch for pressing the metal plate placed on the first lower mold toward the first recess is provided.
The cross-sectional shape of the first recess is
End-side curved portions provided at both end portions in the width direction for forming curved shapes at both end portions in the width direction of the metal plate, respectively.
A central curved portion provided in the center in the width direction for forming a curved shape in the center in the width direction of the metal plate, and a central curved portion.
A metal plate processing apparatus characterized by having. In the metal plate processing apparatus according to claim 1,
In the cross-sectional shape of the first recess, the portion between each end-side curved portion and the central curved portion is an inclined portion extending so as to connect the end-side curved portion and the central curved portion, respectively. A metal plate processing device characterized by being In the metal plate processing apparatus according to claim 2,
A U-bending device that bends the metal plate into a C-shape and then bends the metal plate into a U-shape
A second lower mold that has a second recess that is recessed on the lower side and on which a metal plate bent in a C shape is placed.
A second upper mold having a second punch that presses the metal plate placed on the second lower mold toward the second recess.
Have,
Further, the U-bending device is characterized in that after bending into a U-shape by the second punch, both end portions of the U-shaped metal plate are pressed by the second upper mold. Metal plate processing equipment. When a metal plate is bent into a U shape and then pressed from the U-shaped opening side by a mold to be processed into an annular shape to manufacture a metal tube, the metal plate is processed before being bent into a U shape. Is a metal plate processing method that bends in a C shape.
The mounting process of mounting the metal plate on a lower mold having a recessed recess on the lower side, and
Including a pressing step of pressing the metal plate placed on the lower mold toward the recess.
The metal plate processing method is characterized in that the pressing step is a step of forming curved portions at both side ends in the width direction of the metal plate and at the center in the width direction of the metal plate, respectively.

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