JP2004216388A - Method for molding c-shaped pipe and working device, and c-shaped pipe molded by the molding method and working device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pipe in which a usable space can be secured by reducing a dead space of a pipe to be arranged in a heat exchanger or the like, a working method capable of molding the pipe in less working processes, and a working device. <P>SOLUTION: The C-shaped pipe is molded by the following molding method. The molding method is composed of a process to bend the pipe 10 with a prescribed length into an approximately U-shape by a bending machine 1, a process to insert the pipe 10, which is formed to the U-shape, into a constrained jig 20 having a recessed molding groove 11a, a process to restrain both ends of the U-shaped pipe 10, and a process to insert a core metal 19 into the pipe while pressing the pipe end parts on both sides to the direction of the constrained jig 20. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a pipe forming technique used for a pipe arranged in a heat exchanger or the like, and a pipe used for a pipe joint for connecting the pipe and the pipe, and a processing method for the pipe and a processing apparatus used for performing the processing method. It is about technology.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, components such as a heat exchanger provided in an engine room or a water heater of an automobile are connected by pipes for sending refrigerant, water, and the like. In recent years, the performance of the above-described devices has been improved, and the number of components has increased accordingly, and each component has been arranged at a high density. For this reason, there is an increasing need for space-saving piping, and piping that is bent with a small radius of curvature is required in order to connect components arranged at a high density. This is because, if bending can be performed with a small radius of curvature, for example, a dead space generated at a bent portion of a U-shaped pipe can be reduced.
[0003]
However, when bending is performed with a small radius of curvature, there is a concern that the inside of the bent portion may be buckled, and the outside of the bent portion may have a reduced thickness and deteriorate durability. For this reason, when performing bending with a small radius of curvature, it was impossible to perform bending beyond the minimum radius of curvature determined from the elongation percentage, wall thickness, and the like of the piping material.
[0004]
In order to solve such a problem, conventionally, a first step of bending a pipe at a normal bending radius larger than a minimum radius of curvature, and restraining a side wall of a bent portion of the bent pipe. A known method is a processing method comprising a second step of pressing the pipe end portion with a pressing member while the pipe is being bent (see Patent Document 1). Has been realized.
[0005]
[Patent Document 1]
JP-A-09-1247
[0006]
[Problems to be solved by the invention]
However, the bending method in the related art including the above-mentioned Patent Document 1 and an apparatus used for the bending method can be applied to a single bending operation, but a plurality of bending operations at an adjacent position are possible. Processing is not considered.
In other words, for example, in the case of forming an L-shaped pipe by bending once, it is possible to perform the minimal R bending process, but in the case of bending twice in an adjacent position to form a C-shaped pipe, for example, It becomes difficult to apply.
That is, when trying to form a C-shaped pipe by simply performing the L-shaped bending twice, it is not possible to secure an allowance for the once-formed L-shaped pipe by using a bending apparatus such as a pipe bender. Further, there is a concern that the C-shaped pipe to be formed may be distorted or may have an uneven thickness.
Further, when a C-shaped pipe is formed by the above-described processing method by twice bending, as shown in FIG. 17 (a plan view showing a C-shaped pipe formed by a conventional processing method), both ends of the pipe are non-uniform. The protruding portions 65, 65 become unnecessary portions and need to be cut, and the protruding portions 65, 65 to be cut cause loss.
[0007]
In view of the above, the present invention provides a C-shaped pipe capable of minimizing a dead space as much as possible, and forms the C-shaped pipe without causing distortion or uneven thickness. Provided is a processing method and a processing apparatus used for the processing method.
In addition, the present invention provides a method and a processing apparatus for a C-shaped pipe that enables the C-shaped pipe formed by the processing method and the processing apparatus to be realized with a small number of processing steps and that can be formed without loss. Things.
[0008]
[Means for Solving the Problems]
The problem to be solved by the present invention is as described above. Next, means for solving the problem will be described.
[0009]
That is, in claim 1, a step of bending a pipe of a predetermined length into a substantially U shape by a bending device, and a step of inserting the U-shaped pipe into a restraining jig having a concave forming groove. And forming a C-shaped pipe, which comprises a step of restraining both ends of the U-shaped pipe and a step of inserting a core metal into the pipe while pressing both ends of the pipe in the direction of the restraining jig. .
[0010]
The restraining jig according to claim 2, wherein the restraining jig comprises a left-right split mold, wherein the restraining shaft is formed with a concave forming groove having a circular cross section, and a ring-shaped step is formed at an open end of the concave forming groove. A punch is disposed above the pair of opening ends so as to be able to ascend and descend, and the punch is provided with a mandrel through a predetermined gap in a pipe-shaped base, and the mandrel is projected toward the opening. It is.
[0011]
According to a third aspect of the present invention, the core metal has a circular tip, a bent inside is formed in a straight line, and a bent outside is formed in an arc shape in accordance with the bent shape.
[0012]
According to a fourth aspect of the present invention, there is provided the processing apparatus according to the second and third aspects, wherein the processing method according to the first aspect is used to form a C-shaped pipe obtained by processing a minimal R-bent portion at the bent portion. .
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, an embodiment of the invention will be described.
1 is a schematic view showing a first bending step, FIG. 2 is a perspective view of one side of a mold used in a second bending step, FIG. 3 is a front view of a mold on the other side, and FIG. FIG. 5 is a perspective view of a pressing member used in the second bending step, and FIG. 6 is a plan view of the same.
[0014]
First, processing steps until the C-shaped pipe according to the present invention is formed will be described. In the present embodiment, the C-shaped pipe is formed by a hollow pipe member having a circular cross section.
The C-shaped pipe is formed by a first bending step of performing a bending process with a large radius of curvature and a second bending step of performing a bending process with a small radius of curvature on the pipe member that has been bent to a large radius in the first step.
[0015]
In the first step, a straight pipe member is subjected to bending with a large radius of curvature by a known bending apparatus such as a pipe bender or a cut-off bender, and cut into a predetermined length to form a U-shaped pipe.
As shown in FIG. 1, the U-shaped pipe to be formed is bent by a bending apparatus 1 and then cut to a predetermined length by a pipe cutting machine 2 to be formed. That is, since both sides of the pipe 10 bent in a U-shape are cut out in parallel at the same time, the inclined portion 5 which is formed at the tip of the pipe 10 due to the uneven thickness due to the bending can be cut out, and the pipe of the formed U-shaped pipe is cut. The ends are aligned in parallel on both sides.
[0016]
Next, a second step of processing the U-shaped pipe formed in the first step into a C-shaped pipe having a minimal R-bent portion of the present invention will be described.
In the second step, the dies 11 and 13 as shown in FIGS. 2 and 3 are constituted by two halves, and the restraining jig 20 (FIG. 4) formed by fitting the dies 11 and 13 together. A U-shaped pipe is inserted into the forming groove, and the two punches 16 are pressed against a pressing member 15 projecting from the same side as shown in FIG.
[0017]
As shown in FIG. 4, the restraining jig 20 includes a pair of dies 11 and 13. The pair of dies 11 and 13 are formed in substantially the same shape, and are provided with protrusions 12 and 12 at positions which do not interfere with the molding on both sides of the mating surface of one of the dies 11 shown in FIG. The other mold 13 shown in FIG. 1 is provided with concave portions 14 and 14 which are positioned so that the protrusions 12 can be fitted. Then, the projections 12 of the one mold 11 are fitted into the recesses 14 of the other mold 13 so that the two molds 11 are securely fixed and do not shift.
[0018]
A molding groove 11a (or 13a) having a circular cross section for accommodating a U-shaped pipe and having a concave shape in a side sectional view is formed in the upper surface of the mold 11 (or the mold 13). The forming groove 11a has a size corresponding to the outer diameter of the pipe 10, and a step 11c having a diameter slightly larger than the width (diameter) of the forming groove 11a is provided at the open end of the forming groove 11a. ing. The lower ends on both sides of the forming groove 11a are formed in a square shape so as to be smaller than the radius of curvature of the U-shaped pipe 10, and the bottom of the central projection 20d located between the openings on both sides has the U-shaped bottom. The shape is approximately matched to the radius of curvature of the pipe.
[0019]
When the two molds 11 and 13 are fitted to face each other, the molding grooves 11a and 13a for accommodating the U-shaped pipes of both molds overlap, and a pipe-shaped space capable of accommodating and restraining the bent portion of the U-shaped pipe. A portion (molding groove) 20a (FIG. 4) is formed. Also, the steps 11c, 11c and the steps 13c, 13c of the mold on the other side overlap to form annular steps 20c, 20c.
The steps 20c are provided to form a bulge 10c (FIG. 8) at the pipe end of the pipe, and will be described later in detail.
[0020]
As shown in FIGS. 5 and 6, the pressing member 15 has two punches 16 projecting from the front side (the pressing direction side) of the main body 17. The punches 16 are arranged in parallel with an equal distance between both ends of the pipe so that the protruding ends of the U-shaped pipe constrained by the restricting jig 20 can be pressed.
The punch 16 is composed of a base 18 formed in a pipe shape, and a metal core 19 protruding downward from the center of the base 18 (the restraining jig side is set downward). . The tip 19a of the metal core 19 is processed into a round and pointed shape, the inside 19b is straightly extended downward in a semi-cylindrical shape, and the outside 19c is formed into an R shape (arc shape) according to the shape to be bent. Have been. A pipe-shaped gap is formed between the inner circumference of the base 18 and the outer circumference of the cored bar 19, and the end diameter of the pipe is determined by the gap. The end is press-fitted. That is, by inserting the pipe end into the gap, the end diameter of the pipe to be processed can be corrected. At the same time, the pitch of the pipe to be processed (the distance between the pipe ends) can be corrected according to the distance between the punches 16.
[0021]
Here, a processing method using the restraining jig 20 and the pressing member 15 will be described.
FIGS. 7A and 7B are explanatory views showing a process of processing a U-shaped pipe into a C-shaped pipe, wherein FIG. 7A is a cross-sectional view showing the inside of a restraining jig before processing, and FIG. It is sectional drawing. 8 is an enlarged cross-sectional view showing the inside of the restraining jig during processing, and FIG. 9 is a cross-sectional view showing a restraining jig for forming a bulge. (A) is before bulge forming, and (b) is after bulge forming. Show. FIG. 10 is a plan view of the ball mandrel, and FIG. 11 is an enlarged sectional view of the inside of the restraining jig showing a use state of the ball mandrel.
[0022]
When the U-shaped pipe is sandwiched between the two dies 11 and 13 described above, the bending direction of the U-shaped pipe and the vertical direction of the bending direction are restrained by the restraining jig 20 as shown in FIG. Although there is no gap, gaps 20e are formed on both lower sides of the space.
Then, as shown in FIG. 7B, when the core metal 19 is inserted into the restraining jig 20 while pressing the pipe end of the U-shaped pipe by the pressing member 15, the bent portion of the U-shaped pipe is formed. The outer side 10a is pushed into the gaps 20e and 20e to expand the tube, and at the same time, the bent portion outer side R is formed along the shape by pressing the tip of the cored bar 19. Further, the inside 10b of the bent portion is pressed to the inside of the pipe along the inside of the cored bar 19 to reduce the bend R and is subjected to the minimum R bend processing. Since the metal core 19 has entered the pipe without any gap, buckling does not occur on the inside 10b of the bent portion.
[0023]
Also, in general, when the pipe is bent, the thickness of the bent portion outside 10a becomes thin, and the durability is reduced. However, in the present invention, the bent portion outside 10a is processed while pushing the pipe end. In addition, the thickness can be prevented from being reduced. Conversely, when the pipe end is pushed in, the inside of the bent portion 10b becomes thicker and wrinkles or buckling occurs, but this can be prevented by the core metal 19 inserted inside the pipe.
Further, the protrusion (FIG. 17) on the inner side of the pipe end caused by the change in the wall thickness due to the bending process can be suppressed because the pipe end of the pipe is pressed. The resulting C-shaped pipe is molded. Therefore, no loss occurs.
[0024]
The lengths of the punches 19 protruding from the pressing member 15 are equal, and no force is applied to both sides when pressing the tube end. For this reason, a force is evenly applied to both ends of the pipe, and it is possible to solve the problems such as uneven thickness and distortion that are concerned when obtaining the C-shaped pipe by repeating the conventional L-shaped bending twice.
[0025]
As described above, the U-shaped pipe is restrained by the restraining jig 20 and the C-shaped pipe is formed by simultaneously pressing both ends of the U-shaped pipe with the pressing member, so that the thickness is reduced and the seat is reduced. It is possible to form a C-shaped pipe that has been subjected to a minimum R-bending process at two locations at a close position without fear of bending.
In addition, the end diameter can be corrected and the pitch can be corrected at the same time when the C-shaped pipe is formed, so that various processing steps can be performed at the same time.
[0026]
Further, as described above, when the U-shaped pipe is pressed from the pipe end side by the pressing member to form the C-shaped pipe, the bulge 10c can be formed at the same time. That is, as shown in FIG. 8, when the pipe end is pressed by the pressing member, the outside of the U-shaped pipe is bent, and the bent portion is sandwiched between the annular step 20c and the tip of the punch base 18, so that the C-shaped pipe is bent. A protrusion is formed on the tube end side, and the bulge 10c is formed. It is also possible to form a C-shaped pipe without a bulge by not providing the step 10c.
[0027]
It is also possible to form a bulge later on a C-shaped pipe without a bulge once formed. For example, as shown in FIG. 9, a mold 33 having a groove formed in accordance with the shape of the C-shaped pipe 10 is used, and annular steps 33b and 33b are provided on the pipe end side. Then, the C-shaped pipe 10 is fitted into the groove of the mold 33 and restrained. At this time, there is no gap between the C-shaped pipe 10 and the groove of the mold 33. When the C-shaped pipe 10 is pressed by the pressing member from the pipe end side, the C-shaped pipe 10 is restrained in the groove without any gap, so that bending occurs at the steps 33b, 33b, and the bent portion is pressed by the pressing member. The bulge 10c is formed between the tip 18a of the base 18 and the step 33b.
As described above, the bulge can be formed at the same time as the C-shaped pipe is formed, or can be formed in a separate step after forming the C-shaped pipe.
[0028]
Further, a ball mandrel 21 as shown in FIG. 10 can be used for the pressing member 15.
The ball mandrel 21 is provided with a substantially spherical rocking body 23 at the tip of a straight metal core 22. The diameter of the oscillating body 23 is configured to be slightly smaller than the inner diameter of the pipe 10, and the base of the oscillating body 23 is pivotally supported by a fulcrum shaft 24 fixed to the front end of the cored bar 22 so as to be rotatable. Is provided. The leading end of the core bar 22 is cut obliquely to provide an inclined portion 22a, which is rotatable toward the inclined portion 22a. By attaching the ball mandrel 21 to the distal end of the pressing member 15 and functioning as a punch, the rocking body at the distal end can penetrate deep into the pipe and make the diameter of the pipe constant.
[0029]
That is, as shown in FIG. 11, when the ball mandrel 21 is press-fitted from both ends of the pipe, the rocking body 23 at the tip of the ball mandrel 21 enters the inside of the pipe and is pressed downward along the inner surface of the pipe. Then, the outside 10a of the bent portion of the pipe is pushed in. In addition, since the spherical rocking body 23 enters the back side while moving along the bent portion of the pipe, the pipe diameter does not change between the straight portion and the bent portion. Further, the inside of the bent portion is regulated by the surface of the rocking body 23, so that buckling of the inside can be prevented.
In this manner, the ball mandrel can function as a punch for the pressing member.
[0030]
Since the C-shaped pipe can be formed by the above-described processing method and the processing apparatus used for the processing method, the C-shaped pipe can be formed by a single processing without having to bend twice as in the related art. Therefore, it can be processed in a small number of steps, and there is no fear of distortion or the like due to uneven application of force. In addition, since the pipe end of the formed C-shaped pipe is flat and does not protrude wastefully, loss can be eliminated and cost can be reduced. Further, since the correction of the terminal diameter, the correction of the pitch, and the molding of the bulge can be performed together with the molding of the C-shaped pipe, various types of processing steps can be performed at once, and the number of processing steps can be reduced.
[0031]
Here, a description will be given of an embodiment in a case where the hairpin-shaped U-shaped pipe having a long straight portion is subjected to the minimum R processing. 12A and 12B are cross-sectional views illustrating a method of forming a hairpin-shaped C-shaped pipe. FIG. 12A illustrates a hairpin-shaped U-shaped pipe before processing, and FIG. 12B illustrates a hairpin-shaped C-shaped pipe after processing. FIG.
As shown in FIG. 12 (a), when performing a minimal R-bending process on a U-shaped pipe 42 having a long straight portion like a hairpin, a restraining jig 43 for holding both straight portions 42a of the U-shaped pipe, It is processed by a pressing die 46 that presses a bent portion 42 b protruding outside from the restraining jig 43.
In the restraining jig 43, two pipe-shaped restraining holes are opened in parallel according to the shape of the straight portion 42a of the hairpin-shaped U-shaped pipe, and both straight portions 42a of the hairpin-shaped U-shaped pipe are opened at the restraining holes. -42a is restricted.
The pressing die 46 is provided with a pressing groove 46a having a substantially "C" shape in cross section, and a bent portion 42b of a hairpin U-shaped pipe is fitted into the pressing groove 46a and pressed. I am trying to do it.
[0032]
In the hairpin-shaped U-shaped pipe 42 in which the straight portions 42a on both sides are restrained by the restraining jig 43, metal cores 47 are inserted in advance from the pipe end side to the bent portion side, and the core The ends of the golds 47 are arranged so as to be located at the bent portion of the U-shaped pipe. The metal cores 47 have a circular tip, and the inside of the bent portion has a straight shape, and the outside of the bent portion has an arc shape in accordance with a desired bent shape.
[0033]
When the pressing die 46 is pressed against the bent portion 42b of the hairpin-shaped U-shaped pipe 42 constrained in this manner from the pressing groove 46a side, the bent portion 42b is deformed along the shape of the pressing groove 46a. Then, as shown in FIG. 12 (b), at the position where the pressing die 46 and the restraining jig 43 come into contact, the bent portion 42b becomes the same shape as the shape of the pressing groove 46a, and the minimum R bending process is performed. Is completed, and the hairpin-shaped C-shaped pipe 52 is formed.
The processed hairpin-shaped C-shaped pipe 52 has a smaller protruding length than the hairpin-shaped U-shaped pipe 42 shown in FIG. 12A, and can be arranged in a space-saving manner.
[0034]
That is, in the processing method described above, the pipe is pressed by the pressing member provided with the core, but in the present embodiment, the cores 47 are inserted in advance into the pipe. The pressing is performed by the pressing die 46. By processing with such a processing method, when processing a pipe having a long straight portion such as a hairpin shape, the processing can be performed with a small operation.
[0035]
In addition, the processing method of the hairpin-shaped U-shaped pipe according to the present embodiment can be applied to the normal processing method described above. Conversely, the processing method of the hairpin-shaped U-shaped pipe according to the present embodiment includes the above-described processing method. The method of processing a C-shaped pipe described above can also be applied. That is, when the hairpin-shaped U-shaped pipe of the present embodiment is formed, it is possible to perform processing by restraining the bent portion and pressing with a pressing member having a metal core longer than the tube end. In the above-described method of processing a C-shaped pipe, a core may be inserted in advance from the end of the pipe and pressed from the bent portion.
[0036]
Next, FIGS. 13 and 14 show the processing method and the C-shaped pipe formed by the processing apparatus described above.
13A and 13B are plan views showing one embodiment of a C-shaped pipe, in which FIG. 13A shows a C-shaped pipe with no brazing material, FIG. 13B shows a C-shaped pipe with a brazing material attached thereto, and FIG. It is a top view which shows a form, (a) is a figure without a brazing material, (b) is a figure which shows the C-shaped pipe to which the brazing material was attached, and FIG. 15 is a restraining jig for shaping another form of C-shaped pipe. FIG.
The C-shaped pipe 40 shown in FIG. 13 is formed by the processing method and the processing apparatus described above. The C-shaped pipe 40 is formed such that the radius of curvature of the inside 40a of the bent portion is as close to zero as possible. By being formed in this way, it is possible to arrange the rectangular component so as to sandwich it, and to effectively use the space.
Also, the C-shaped pipe 40 shown in FIG. 13A has bulges 40b formed on both ends of the pipe and can be used as a pipe joint, and can join two pipes even in a small space. It becomes. In a C-shaped pipe 40 shown in FIG. 13B, a ring-shaped brazing material 41 is provided near the bulge 40b. The brazing material 41 is made of a metal having a low melting point, and is securely fixed when another pipe is connected to the C-shaped pipe 40 to enhance the sealing property.
[0037]
Further, by using a different shape of the groove of the restraining jig, a C-shaped pipe 50 having a different shape as shown in FIG. 14 can be formed. The C-shaped pipe 50 can be formed by a restraining jig formed by opposing two molds 53 each having a half-ring-shaped forming groove 53a as shown in FIG.
That is, a C-shaped pipe having two minimum R-bends at adjacent positions can be processed into various shapes depending on the application.
The C-shaped pipe 50 shown in FIG. 14A has bulges 50a formed on both ends of the pipe and can be used as a pipe joint. The C-shaped pipe 50 shown in FIG. The brazing material 51 is provided near the bulge 50a.
[0038]
Here, an example of use of the C-shaped pipe will be described with reference to FIG.
FIGS. 16A and 16B are explanatory diagrams comparing a C-shaped pipe of the present invention with a conventional pipe. FIG. 16A is an explanatory diagram showing an example of use of a conventional pipe, and FIG. It is explanatory drawing which shows an example.
For example, as shown in FIG. 16A, when a pipe formed by bending according to a conventional technique is inserted into a metal block 26 having a hole 26a formed in accordance with the shape of a pipe end of the pipe. However, the inside of the bent portion of the pipe is caught and cannot be inserted as far as it will protrude largely outside the mass 26. However, as shown in FIG. 16 (b), when the C-shaped pipe of the present invention is inserted into the mass 26 similar to the above, the inside of the bent portion of the C-shaped pipe is bent to a minimum R, so that the straight portion is It can be inserted deeper into the mass 26 as compared with the one of the above. That is, the protrusion length L2 of the C-shaped pipe of the present invention is smaller than the protrusion length L1 of the conventional pipe, and the area occupied by the pipe is smaller. Therefore, the use of the C-shaped pipe of the present invention makes it possible to make the conventional dead space usable.
[0039]
Then, the C-shaped pipe is disposed in a heat exchanger 60 provided inside, for example, a water heater. That is, as described above, when a C-shaped pipe is used, the protruding length of the pipe is reduced, and the area occupied by the pipe is reduced, so that a heat exchanger smaller than before can be realized.
[0040]
【The invention's effect】
The present invention is configured as described above, and has the following effects.
[0041]
That is, as set forth in claim 1, a step of bending a pipe of a predetermined length into a substantially U shape by a bending apparatus, and a step of inserting the U-shaped pipe into a restraining jig having a concave forming groove. And forming a C-shaped pipe from the step of restraining both ends of the U-shaped pipe and the step of inserting the core metal into the pipe while pressing both ends of the pipe in the direction of the restraining jig,
A C-shaped pipe without distortion and uneven thickness can be formed. Also, in order to form a C-shaped pipe in the prior art, two minimal R-bending processes were required. However, according to the present invention, it is possible to form a C-shaped pipe in a single operation. We can process the shape pipe. In addition, no loss occurs because the pipe end does not protrude during processing.
[0042]
3. A restraining jig as defined in claim 2, wherein said restraining jig comprises a left-right split mold, wherein said restraining shaft has a concave forming groove having a circular cross section, and a ring-shaped step portion is formed at an open end of said concave forming groove. Then, a punch is arranged above and below the pair of opening ends so as to be able to move up and down, and the punch is provided with a mandrel through a predetermined gap in a pipe-shaped base, and the mandrel protrudes toward the opening. So
It is possible to simultaneously press the pipe ends at both ends, and it is possible to form a C-shaped pipe without distortion and uneven thickness. Further, it is possible to correct the pipe end diameter, correct the pitch, and form the bulge simultaneously with the formation of the C-shaped pipe, and it is possible to perform a plurality of processing steps at the same time.
[0043]
As shown in claim 3, since the tip of the core metal has a circular shape, the inside of the bend has a linear shape, and the outside of the bend has an arc shape in accordance with the bent shape.
While preventing buckling on the inside of the bend, the C-shaped pipe can be formed without damaging the pipe on the outside of the bend.
[0044]
According to a fourth aspect of the present invention, with the processing apparatus according to the second and third aspects, the processing method according to the first aspect allows the bending portion to be processed into a minimal R-bent portion, so that it is obtained.
The area occupied by the pipes when arranging them in a heat exchanger, etc. is reduced, and extra dead space can be omitted, so that the available space increases and the pipes can be efficiently placed between components arranged at high density. Can be arranged.
[Brief description of the drawings]
FIG. 1 is a schematic view showing a first bending step.
FIG. 2 is a perspective view of one side of a mold used in a second bending step.
FIG. 3 is a front view of a mold on the other side.
FIG. 4 is a plan view of a pair of molds.
FIG. 5 is a perspective view of a pressing member used in a second bending step.
FIG. 6 is a plan view of the same.
FIG. 7 is an explanatory view showing a process of processing a U-shaped pipe into a C-shaped pipe.
FIG. 8 is an enlarged cross-sectional view showing the inside of a restraining jig during processing.
FIG. 9 is a sectional view showing a restraining jig for forming a bulge.
FIG. 10 is a plan view of a ball mandrel.
FIG. 11 is an enlarged sectional view of the inside of a restraining jig showing a use state of a ball mandrel.
FIG. 12 is a cross-sectional view illustrating a method of forming a hairpin-shaped C-shaped pipe.
FIG. 13 is a plan view showing one embodiment of a C-shaped pipe.
FIG. 14 is a plan view showing another form of the C-shaped pipe.
FIG. 15 is a plan view showing a restraining jig for forming a C-shaped pipe of another embodiment.
FIG. 16 is an explanatory diagram for comparing a C-shaped pipe of the present invention with a pipe of the related art.
FIG. 17 is a plan view showing a C-shaped pipe formed by a conventional processing method.
[Explanation of symbols]
1 bending equipment
10 pipes
10a Mold groove
19 core
20 Restraint jig

Claims (4)

A step of bending a pipe of a predetermined length into a substantially U-shape by a bending apparatus, a step of inserting the U-shaped pipe into a restraining jig having a concave forming groove, and a step of bending both ends of the U-shaped pipe. A method of forming a C-shaped pipe, comprising a step of restraining and a step of inserting a metal core into the pipe while pressing both ends of the pipe in the direction of the restraining jig. A restraining jig comprising a left-right split mold, wherein a recess-shaped forming groove having a circular cross section is formed in the restraining shaft, and a ring-shaped step portion is formed at an opening end of the recessed forming groove. A C-shaped pipe processing apparatus in which a punch is disposed so as to be able to ascend and descend upward, a core is provided in a pipe-shaped base through a predetermined gap, and the core projects toward the opening. 3. The C-shaped pipe processing apparatus according to claim 2, wherein the core metal has a circular tip, a bent inner side is formed in a straight line, and a bent outer side is formed in an arc shape in accordance with the bent shape. A C-shaped pipe obtained by processing the minimum R-bent portion at the bent portion by the processing method according to claim 1 using the processing device according to claim 2.

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