JP2013086159A - Manufacturing method for pipe material, pipe material produced with the same method, and exhaust gas catalyst system using the pipe material as outer cylinder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new manufacturing method for a pipe material capable of firmly joining an end edge of a workpiece made from a metal plate material without welding the end edge of the workpiece.SOLUTION: In the manufacturing method for a pipe material, before joining the end edges 11 of the workpiece W made from a metal plate material, fitting claws 12 are formed on one end edge 11, receiving grooves 13 for fitting the claws 12 are formed on the other end edge 11, and then the end edges 11 of the workpiece W are joined by fitting the claws 12 to the receiving grooves 13. Locking sections 14 being hooked each other by resisting to force in case when the pipe material 1 is forced to expand along an outer surface after being joined are formed on the claws 12 and the receiving grooves 13.

Description

  The present invention relates to a pipe material formed by joining the edge portions of a workpiece made of a metal plate material, and in particular, a novel pipe material that can be firmly joined without welding the edge portions of the workpiece. The present invention relates to a manufacturing method, this pipe material, and an exhaust gas catalyst device in which this is applied to an outer cylinder.

In general, in an engine that obtains mechanical power by exploding and burning oil in a cylinder, harmful gases such as CO (carbon monoxide), HC (hydrocarbon), and NO _x (nitrogen oxide) are contained in the exhaust gas. Therefore, a catalyst device (purification device) that reduces this kind of harmful substances is incorporated in the exhaust gas discharge path such as a muffler and an exhaust pipe.
As this catalyst device, a monolith type in which a honeycomb body as a core piece whose cross section is formed in a honeycomb shape is fitted into an outer cylinder is well known (see FIG. 1).

By the way, most of such outer cylinders are usually pipe materials having a cylindrical shape. In manufacturing (manufacturing), for example, a metal plate having a substantially constant thickness is rounded and formed into a cylindrical shape, and then this seam is formed. A technique for welding and joining portions (seams) is known, and such a pipe material is also called a welded steel pipe (see, for example, Patent Document 1).
By the way, there is also a seamless production method for pipe material, which is made by first opening a small pilot hole in a metal material, and expanding the pilot hole while reducing the wall thickness. It is a technique to obtain the pipe material. Of course, this is seamless and does not require welding, and is called “seamless pipe” or “seamless steel pipe”.

In obtaining the above-described welded steel pipe, since welding is performed in the longitudinal direction of the steel pipe, the reliability of the welding quality often becomes an essential problem of the product. In other words, it may be unclear whether welding has been reliably welded to the inside even though welding may seem to be good in appearance. To suppress the defective rate of the finished product (welded product) High technology is required, and the cost tends to increase accordingly.
Thus, conventionally, when obtaining a pipe material by rounding a metal plate material, it has been considered that welding is indispensable for joining edge portions. However, a technique that does not require welding, in particular, a metal plate material is rounded into an O-shape. At the time of O-bending, there is a need for a technique that can also join joints.

JP-A-5-161920

  The present invention has been made in view of such a background, and is based on the premise that a pipe material (steel pipe) is obtained from a metal plate, but the end edge (seam) is joined without welding. More specifically, a novel pipe material manufacturing method that enables jointing of edge portions when O-bending is performed to round a metal plate (workpiece) into a cylindrical shape, and The present inventors have attempted to develop a pipe material manufactured by this method and an exhaust gas catalyst device in which this pipe material is applied to an outer cylinder.

First, the manufacturing method of the pipe material according to claim 1 is:
It is a method of obtaining a pipe material by joining the edges of a workpiece made of a metal plate material,
Prior to joining the edge portions, the workpiece is formed with a claw that fits into one edge portion, and a receiving groove that fits the claw is formed at the other edge portion, and the claw is fitted into the groove. To join the edges of the workpiece,
Further, the claw and the groove are characterized in that when the pipe material after joining is about to spread along the outer surface, a hooking portion is formed which is caught against this force. .

Moreover, in addition to the requirements of the said Claim 1, the manufacturing method of the pipe material of Claim 2 WHEREIN:
In the initial flat state, the fitting claw is formed in a size larger than the receiving groove in the planar projection state,
Thereafter, prior to joining of the edge portions, the claw is three-dimensionally bent into a size smaller than the receiving groove in a planar projection state and is fitted into the groove in this state, and then flattened by crushing, It is characterized in that the outer shell is joined so as to be in close contact with the groove.

Moreover, in addition to the requirements of the said Claim 1 or 2, the manufacturing method of the pipe material of Claim 3 WHEREIN:
The metal plate material used as the workpiece is only one single plate, and both ends of the single plate workpiece are joined together to obtain a single pipe material. It is.

Moreover, in addition to the requirements of the said Claim 1, 2, or 3, the manufacturing method of the pipe material of Claim 4,
The fitting claw and the receiving groove are formed in an isosceles trapezoidal shape in a plan view in an initial flat state, and the isosceles trapezoidal leg portion functions as the hooking portion. Is.

Moreover, in addition to the requirements of the said claim 1, 2, 3 or 4, the manufacturing method of the pipe material of Claim 5,
The workpiece is blanked from a metal plate having an appropriate plate thickness,
In addition, when the mounting hole is opened in the radial direction of the pipe material as a finished product, the mounting hole is also opened at the same time when the workpiece is blanked.

Moreover, in addition to the requirements of the said Claim 1, 2, 3, 4 or 5, the manufacturing method of the pipe material of Claim 6,
The joining of the edge portions is characterized in that both burrs generated on the claw side end surface and the groove side end surface are positioned on the inside and outside of the pipe material.

Moreover, in addition to the requirements of the said Claim 1, 2, 3, 4, 5 or 6, the manufacturing method of the pipe material of Claim 7,
In the pipe material, an appropriate fluid passes or is accommodated, and the edge portion is joined so that the fluid does not leak from the inside of the pipe to the outside of the pipe at the joining portion. Is a feature.

The pipe material according to claim 8 is:
A pipe material manufactured by joining the edge portions of a workpiece made of a metal plate material, and the manufacturing method according to claim 1, 2, 3, 4, 5, 6 or 7 is applied to the pipe material. It is characterized by this.

The exhaust gas catalyst device according to claim 9
An exhaust gas catalyst device that purifies exhaust gas by a catalyst that is formed by providing a honeycomb body inside an outer cylinder body into which exhaust gas is fed, and is attached to the flow path surface,
A pipe material according to claim 8 is applied to the outer cylindrical body.

The above-described problems can be solved by using the configuration of the invention described in each of the claims.
First, according to the first, eighth, and ninth aspects of the invention, since the pipe edge is formed by joining the edge portions of the workpiece by fitting the claws and the grooves having the latching portions to each other, the end edge serving as a seam is formed. The pipe material can be obtained without performing welding for joining the parts. Incidentally, conventionally, a pipe material obtained by rounding a flat metal workpiece is also called a welded steel pipe, and it has been naturally considered that welding is performed for joining edge portions.
Moreover, since the edge part of a workpiece | work can be joined without welding, the reduction of a welding process and the simplification of the manufacturing process of a pipe material can be achieved. Of course, it is possible to completely eliminate welding defects (joint defects) that have conventionally occurred during welding.
Furthermore, in obtaining the pipe material as in the present invention, it is necessary to purchase a commercially available product, or purchase a long pipe material and cut it to a desired length. However, in such a case, the off-the-shelf product already formed into a pipe shape is often expensive (especially in the case of overseas), and therefore the present invention (and the edge) can be obtained from a metal plate material. The welding of the parts does not require welding) is also very effective in that the pipe material can be obtained at a very low cost.

Further, according to the inventions of claims 2, 8, and 9, after the claw that was initially formed in a size larger than the groove in the planar projection state is reduced and bent so as to be smaller than the groove in the planar projection state, Since the claw is crushed and then flattened and brought into close contact with the groove, the claw can be surely received in the groove. In addition, since the hooks and grooves are provided with latching portions, the claws are crushed into the latching portions as the claws are crushed, so that the claws and the grooves can be brought into intimate contact (workpieces). ) Can be securely and firmly joined to each other.
Incidentally, when the claw is not reduced and bent, a claw having a large size is forcibly pushed into the groove, and in some cases, a gap may be formed at the joint. Even if the indenting process itself can be managed, it is possible that the process will be accompanied by an excessive (excessive) load. Furthermore, depending on the size of the indentation force, the processing speed, or the overlapping dimension of the claw and the groove, the groove may tear. However, in the present invention, such a situation can be almost completely eliminated.

In addition, according to the inventions of claims 3, 8, and 9, in order to obtain a single pipe material by using only one single plate as a workpiece, a joint (seam) formed in one pipe material is also provided. Only one place (one piece) is provided in the longitudinal direction, so that a pipe material having high strength (strength against pressure from the inside) can be obtained, and processing to form a pipe can be easily performed.
In addition, when a plurality of metal plate materials are connected in series to form a workpiece and this is rounded in the connection direction to form a single pipe material, a pipe material having a large diameter even from a small size metal plate material However, it is considered that there is a plurality of joints (seams) formed in the axial direction for one pipe material, and the strength against internal pressure is also reduced.

  According to the inventions of claims 4, 8, and 9, the claw and the groove form an isosceles trapezoidal shape in a flat state before being subjected to the bending process, and the leg portion is defined as the latching portion. Therefore, the concrete shape of the claw and the groove that can obtain a high joining force without performing welding is realized.

  According to the fifth, eighth, and ninth aspects of the present invention, when a plurality of mounting holes (holes) are formed in the pipe material as a finished product in the radial direction, the mounting holes are used for blanking the workpiece. Since the holes are simultaneously opened at the time of punching (at the time of punching), the pipe material can be obtained very efficiently. That is, when the mounting hole is opened for the first time in the state of the pipe material or at the stage of forming the pipe material, for example, the pipe material is often opened while rotating at each opening location, which is extremely It was a laborious work. In this regard, in the present invention, since such a hole opening operation is performed together with blanking of the workpiece, even if there are a plurality of mounting holes, the hole shape is not a circular shape (a circular shape in plan view). (For example, polygons and stars), the attachment holes can be formed (opened) extremely easily and precisely, and the pipe material can be obtained efficiently.

  According to the invention described in claims 6, 8 and 9, since the end edges are joined so that burrs generated on the end surface on the claw side and the end surface on the groove side are located on the inner side and the outer side of the pipe material, Inclined end faces that occur during processing when forming grooves and grooves (for example, shearing) are almost matched, and it is easy to adopt a structure that makes it difficult for gaps to form in the joints, and therefore a structure that improves the sealing performance of the joints. It becomes.

  Further, according to the inventions according to claims 7, 8, and 9, since an appropriate fluid passes or is accommodated inside the pipe material and the end edges are joined so that the fluid does not leak out of the pipe. Even without welding, high sealing performance can be secured at the joint. Moreover, since a fluid does not leak from a junction part, a pipe material can be applied to various uses.

Sectional drawing (a) which shows the exhaust silencer unit which applied the pipe material of this invention as an outer cylinder of an exhaust gas catalyst apparatus, the perspective view (b) which shows this exhaust gas catalyst apparatus, and the joining condition of an edge part are shown It is a perspective view (c). A plan view and an end view (a) showing an example of a metal plate material (work) blanked in forming a pipe material, and a fitting claw and a receiving groove formed on an edge portion of the metal plate material are enlarged. It is a top view (b) shown. It is the end view (a) of the workpiece | work which shows a mode that the reduction | restoration bending process was performed to the fitting nail | claw by the preliminary bending process after blank removal, and the perspective view (b) which shows this workpiece | work from the back side. It is explanatory drawing (a) * (b) which shows a mode that the workpiece | work after a preliminary | backup bending process is performed U-bending, and the perspective view (c) which shows an example of the workpiece | work after a U-bending process. Explanatory drawing (a) showing a state of performing O-bending on the workpiece after U-bending, and an enlarged state in which the reduced-fitting fitting claw is flattened by this O-bending and is firmly adhered to the receiving groove. It is sectional drawing (c) which shows how to match | combine the nail | claw and the end surface of a groove | channel suitable for obtaining the junction part of a close_contact | adherence state, and the VV line sectional drawing in this figure (b). is there. It is a top view which shows the other Example which formed the nail | claw and the groove | channel in the planar view circle shape in the state (a) before fitting, and the state (b) after fitting. It is explanatory drawing which shows the other Example which was made to obtain one pipe material from several blank materials, (a) shows the state which connected the several blank materials in series, and formed the one workpiece | work. It is a top view, (b) is a perspective view which shows a mode that the said workpiece | work was rolled in the said connection direction and it formed in the pipe material.

The mode for carrying out the present invention includes one described in the following embodiments, and further includes various methods that can be improved within the technical idea.
In the description, the outline of the exhaust gas catalytic device S to which the pipe material 1 of the present invention can be applied as the outer cylinder S1 will be described first, and then the method for manufacturing the pipe material 1 of the present invention will be described.

  As shown in FIG. 1 as an example, the exhaust gas catalyst device S is incorporated in an exhaust silencer unit U, and purifies the exhaust gas G discharged from the engine after combustion before being released into the atmosphere. A catalyst (catalyzer material) for reducing harmful substances is formed on the wall surface of the flow path of the exhaust gas catalytic device S, and the exhaust gas G contacts the catalyzer material while passing through the exhaust gas catalytic device S. To be purified.

Such an exhaust gas catalytic device S includes an outer cylinder S1 that is opened forward and backward, and a honeycomb body S2 that is provided inside the outer cylinder S1. Note that the honeycomb body S2 has a cross section (flow path cross section) formed in a honeycomb shape so as to ensure a large contact area with the exhaust gas G.
Incidentally, in order to form such a honeycomb body S2, first, corrugated processing (corrugated processing) is first formed from a single metal plate material (flat plate), and a corrugated sheet (corrugated sheet having a channel cross-sectional waveform) is formed. Generally, the corrugated sheet is wound while being overlapped with another flat plate to form the honeycomb body S2. Here, the reason why the corrugation is applied to the flat plate is to form an exhaust gas passage as a cell.

The pipe material 1 of the present invention can be applied as the outer cylindrical body S1 of the above-described exhaust gas catalyst device S. Hereinafter, a method for manufacturing such a pipe material 1 will be described.
Here, as the pipe material 1 described below, for example, both openings have a straight shape (so-called straight pipe) having substantially the same size (diameter dimension), and the workpiece W is a single plate (metal plate material). ) Is applied, and the workpiece W is rounded and both end edges 11 are joined together to obtain a single pipe member 1. For this reason, in the basic embodiment described below, the cross-sectional shape of the pipe material 1 is also circular. In addition, the code | symbol 10 shown in FIG.1 (b) is a hole opened, for example in order to install the pipe material 1, etc., and this specification makes this a mounting hole for convenience (FIG.2 (a)). (The same applies to FIG. 3B). In addition, a plurality of such attachment holes 10 are often equally arranged in the radial direction of the pipe material 1. Of course, such a mounting hole 10 is not only for fixing and installing the pipe member 1 to another member. For example, as shown by the phantom line in FIG. 1B, other small-diameter pipes (branch pipes) It is also possible to use (apply) 10A or the like as a hole for connecting, and in that sense, in the above description, it is described as “for convenience (referred to as mounting hole 10)”.
Incidentally, conventionally, when the metal plate material is rolled to obtain the pipe material 1, the end edge portions 11 (joints) are generally joined by welding. For this reason, the conventional pipe material 1 is also a welded steel pipe. In the present invention, a claw 12 and a groove 13 are formed on the end edge portion 11 so as to be engaged with each other, and the claw 12 is fitted into the groove 13 so that the end edge portion does not require welding. 11 is joined. Of course, seamless (non-welded type) seamless pipes are also known as pipe materials, but this is fundamental to the present invention because the workpiece for forming the pipe material is not made of a metal plate material. The technical idea is different (not related to the present invention).

  Hereinafter, the manufacturing method of the pipe material of this invention is demonstrated. The pipe material 1 is basically manufactured in the order of blanking, preliminary bending (claw reduction bending), U bending, and O bending (round bending). explain. Here, each process corresponding to each processing is provided with a reference numeral. Specifically, P1 is assigned to the blanking process, P2 is assigned to the preliminary bending process, P3 is assigned to the U bending process, and P4 is assigned to the O bending process. Is. Moreover, in this specification, the metal plate material (blank material in a present Example) used as the starting material of the pipe material 1, and the intermediate workpiece until it joins an edge by bending this are called the workpiece | work W. .

(1) Blank removal (blank removal process P1)
In the blank removing process P1, for example, as shown in FIG. 2A, the diameter dimension (opening size) and the length dimension (axial dimension) of the target pipe material 1 are set in the vertical and horizontal directions of the blank material. Of course, the workpiece W is punched into a substantially rectangular shape in plan view as a dimension, and in this embodiment, the fitting claw 12 is received by the end edge 11 of the workpiece W (a butting portion that becomes a joint when rounded) and is received. The workpiece W is punched out so as to have the groove 13.

Here, the fitting claw 12 and the receiving groove 13 are for joining the end edge portion 11 of the workpiece W, and in the present invention, the welding required for joining the end edge portion 11 of the workpiece W is thereby performed. Is to be abolished. Hereinafter, in this specification, a fitting nail | claw (12) and a receiving groove | channel (13) may be simply called a nail | claw (12) and a groove | channel (13).
The fitting claw 12 and the receiving groove 13 are formed so as to be hooked to each other in a state where the claw 12 is fitted into the groove 13 as described above. In other words, the latching portion 14 has a claw 12 fitted in the groove 13 and a force of spreading along the circumferential direction (outer surface) acts on the pipe material 1 in which the end edge portions 11 are joined together ( Even if the joints are separated in the circumferential direction), it can be said that they are intended to be caught against each other against this force and not to separate.

Furthermore, as shown in the plan view of FIG. 2B, the fitting claw 12 and the receiving groove 13 in this embodiment are configured so that the individual shapes of the claw 12 and the groove 13 are substantially isosceles trapezoidal shapes. The inclined leg portion of the isosceles trapezoid is the hook portion 14.
Further, when the claw 12 and the groove 13 are viewed as isosceles trapezoids, as shown in FIG. 2B, the upper base is a · A, the lower base is b · B, and the height is h · H. Then (both small letters are the dimensions on the claw 12 side and uppercase letters are the dimensions on the groove 13 side), the upper and lower bases are set so that the claw 12 has a larger dimension than the groove 13 ( For example, the height is set to about 0.2 to 0.3 mm), and the height is set to approximately the same length in the claw 12 and the groove 13. That is, such dimension setting is expressed by the following equation.
a> A
b> B
h ≒ H

Here, the upper base a and the lower base b on the claw 12 side are made larger than the upper base A and the lower base B on the groove 13 side, so that the outline (outside) of the claw 12 is firmly attached to the groove 13. This is to increase the joining force of the end edge portion 11 (how to fit the claw 12 will be described later).
The height dimension h · H when the claw 12 and the groove 13 are isosceles trapezoids is set to be substantially the same for the claw 12 and the groove 13 because a gap is generated at the joint (joint) of the workpiece W. This is to make it difficult to let them. That is, when the claw 12 and the groove 13 are viewed as an isosceles trapezoid, the height dimension h of the claw 12 hits the pipe material 1 in the circumferential direction, and the height dimension h of the claw 12 is greater than the height dimension H of the groove 13. This is because if it is increased, it is considered that a gap is easily formed at the joint between the claw 12 and the groove 13. In other words, if the height dimension h on the claw 12 side is larger than the height dimension H on the groove 13 side, a gap is likely to be formed at the seam between the claw 12 and the groove 13 from the beginning. This is considered to be a situation where the portions 11 are easily separated from each other.

In this configuration, that is, the latching portion 14 that is hooked to the claw 12 and the groove 13 is formed, and the claw 12 that is formed to be slightly larger than the groove 13 in a planar projection state is firmly attached to the groove 13. By doing so, both edge portions 11 of the workpiece W can be strongly joined without performing welding, which was conventionally considered to be natural.
Further, when the pipe material 1 is applied as the outer cylinder S1 of the exhaust gas silencing unit U, the exhaust gas G flows inside the pipe material 1, and the exhaust gas G flows from the joint (seam) to the outside. It does not leak. That is, the above-described configuration not only enables the end edge 11 of the workpiece W to be joined to such an extent that welding is not required, but also has an effect of ensuring a high level of airtightness (sealability) of the joint of the pipe material 1. It is what you play. Of course, when the inside and outside of the pipe material 1 may communicate with each other (when the fluid flowing inside the pipe material 1 may leak outside from the joint), the height dimension h of the claw 12 is It is also possible to make it larger than the height dimension H of the groove 13.

Incidentally, in this embodiment, it is explained that the workpiece W is blanked from a metal plate material that has been basically rolled to a constant thickness, and the mounting hole 10 is also opened at the time of blanking. It is preferable to do. That is, when the attachment hole 10 is opened for the first time in the state of the pipe material 1 (when the pipe material 1 is formed), for example, the opening work is performed while rotating the pipe material 1 for each opening location. (For example, if it is a three-dimensional arrangement, the pipe material 1 needs to be rotated three times while rotating the pipe material 1 by 120 degrees). This is an extremely time-consuming operation. Since the attachment holes 10 can be formed simultaneously with the blanking of the workpiece W, the pipe material 1 can be formed extremely efficiently. Further, in the above-described method of simultaneously forming the mounting hole 10 at the time of blanking, a complicated hole shape can be easily and precisely set by setting a target hole shape punching die when blank material (work W) is punched. The attachment hole 10 can be formed in the. That is, if the mounting hole 10 is punched in advance at the blank material stage, various shapes such as an elliptical shape, a polygonal shape, and a star shape are considered after the blank material is expected to be three-dimensionally formed into a tubular shape as the pipe material 1. The attachment hole 10 can be freely opened. Incidentally, when the mounting hole 10 is opened for the first time in the state of the pipe material 1 or when the pipe material 1 is formed, for example, drilling by drilling cannot open a polygonal shape or a star shape. is there. On the other hand, for example, when opening a pipe material using a mold, it may be possible to open a polygonal shape or a star shape, but the mold structure becomes extremely complicated and its practicality is extremely low. It is.
Furthermore, when the workpiece W is blanked, the pipe material 1 can be obtained more efficiently by punching the workpiece W so as to have not only the mounting holes 10 but also the claws 12 and the grooves 13. It is.
Of course, if there is a metal plate previously formed in a rectangular shape with an appropriate plate thickness, this can also be applied as a starting material (work W). In this case, the work W is subjected to punching processing. It is also possible to form the attachment hole 10 and perform chamfering or cutting-off processing to form the claw 12 and the groove 13 (after-processing necessary portions).

(2) Pre-bending process (pre-bending process P2)
Next, the preliminary bending process (preliminary bending process P2) will be described. The pre-bending process P2 is a bending process (process) in which the claw 12 punched larger than the groove 13 in a planar projection state is formed in a reduced state (slimmed). In this embodiment, for example, as shown in FIG. The bottom bottom b of the claw 12 (the wide bottom bottom b when viewed as an isosceles trapezoid) is bent so as to be inside the pipe member 1.
Further, the dimension b ′ (reduced width dimension b ′ in a planar projection state) is, as shown in FIG. 3A, the upper base A of the groove 13 (the narrow upper base when viewed as an isosceles trapezoid). B) is bent so as to be smaller than A) (b ′ <A), so that the claw 12 punched larger than the groove 13 in a planar projection state can be reliably accommodated in the groove 13. is there. Here, the reference numeral “12a” is attached to the claw that has been subjected to the reduction bending process, and it is used when it is desired to clearly distinguish the claw 12 from before the reduction bending process.

The pre-bending direction (bending direction for reducing the planar projection size of the claw 12) is not limited to the inner side direction of the pipe material 1, but is bent so as to rise to the outer side of the pipe material 1. It doesn't matter.
Further, in this embodiment, as shown in FIG. 3B as an example, the claw 12 and the groove are formed in this preliminary bending process so that the claw 12a after the reduced bending process can be easily fitted into the groove 13 or crushed. Although the process of bending the end edge portion 11 of the workpiece W having 13 to the inside of the pipe member 1 as a whole is also performed, this is not necessarily essential. In other words, the preliminary bending process can be said to be a reduction bending process of the claws 12 and an important process in the present invention.

(3) U bending process (U bending process P3)
Next, the U bending process (U bending process P3) will be described. As an example, as shown in FIGS. 4A and 4B, the U-bending step P3 bends the workpiece W after the pre-bending process (slender bending process) that is substantially flat as a whole into a U-shaped section. It is a process (process), and thereby, both end edges 11 that receive the joining thereafter are raised so as to face each other.
In the present embodiment, as described above, the workpiece W is U-bent so that the one that is reduced and bent during the preliminary bending process (the one that has been raised) is placed inside the pipe material 1. Here, reference numerals 21 and 22 in the drawing are female and male types respectively applied to the U-bending process. In this embodiment, the workpiece W is set on the female die 21 cut into a semi-cylindrical shape. (Positioning) The workpiece W is bent into a U-shaped section by pressing with a cylindrical male die 22 from above.

(4) O bending process (O bending process P4)
Next, the O bending process (O bending process P4) will be described. As an example, the O bending process P4 is performed in a state in which the cored bar 25 is housed inside the work W after U bending (the inner side of the U-shaped cross section is substantially in the middle), as shown in FIG. In this process, the workpiece W is formed into a pipe shape (cylindrical shape) having an O-shaped cross-section. Of course, in this O-bending process, as shown in FIG. 5B, for example, as shown in FIG. 5B, the claw 12a after the reduced bending process has a flat shape (specifically, a curved shape along the side peripheral surface of the core metal 25). ) And the outer (outside) of the claw 12a is brought into close contact with the groove 13. This point is greatly different from general O-bending. In other words, in the present invention, both edge portions 11 of the workpiece W are firmly joined by such O bending (pressing), whereby welding to the part (welding conventionally performed for joining) is performed. ).
Here, reference numerals 26 and 27 in the figure respectively denote a receiving die and a pressing die that are applied to the O-bending process, and in this embodiment, the cored bar 25 is bitten into the receiving die 26 hollowed out in a semi-cylindrical shape. The workpiece W is accommodated and pressed from above by a pressing die 27 cut into a semi-cylindrical shape to bend the workpiece W into an O-shaped cross section and firmly join the edge 11.

  In addition, since the latching | locking part 14 which mutually catches is formed in the nail | claw 12 and the groove | channel 13, as shown also in FIG.5 (b), the meat of the nail | claw 12a is made into the groove | channel 13 by crushing (planarization) processing. As it enters (hangs into) the (holding portion 14), the both end edge portions 11 of the workpiece W are pulled so as to approach each other, and are joined more firmly. This also contributes to preventing the exhaust gas G from leaking out from the joint when, for example, the exhaust gas G is caused to flow inside the pipe material 1 (improvement of sealing performance). Of course, such a latching part 14 also bears the effect | action which does not isolate | separate the pipe material 1 (joining part) after completion in the circumferential direction.

As for the alignment of the end faces of the claw 12 and the groove 13, for example, as shown in FIG. 5C (i), when forming the claw 12 and the groove 13, for example, in this embodiment, punching is performed on the metal plate material. It is preferable to perform end face alignment (insertion of the claw 12a into the groove 13) so that the burr (burr) bu that is inevitably generated at the time of processing (at the time of shearing) is located on the inside and the outside of the pipe material 1. For example, in this embodiment, it is desirable to take a blank in consideration of the formation state of the burr bu as described above when the initial blank is taken. As a result, the inclined end surfaces generated when the claw 12 and the groove 13 are formed can be matched so as to be substantially matched, and a structure in which a gap is hardly formed in the joint portion and a structure that improves the sealing performance of the joint portion is adopted. It will be easy.
Here, the burr (bue) bu is a protrusion-like portion generated on the shearing surface (shear end portion) of the workpiece W. On the other hand, roundness (roundness caused by pressing of the punch) generated on the shearing surface (shear start portion) of the workpiece W is a sag roro, and this sagroro is normally generated at a position facing the burr bu on one shearing surface. For this reason, the burr bu referred to the end face alignment between the claw 12 and the groove 13 is the same as the sag ro.
Incidentally, when the burr bu and sag ro generated during the shearing process are positioned on the same side of the pipe material 1 and the end faces of the claw 12 and the groove 13 are aligned with each other, for example, as shown in (ii) of FIG. In addition, since the inclined end surfaces do not match, a V-shaped groove is generated by the inclined surface, and a gap is likely to be formed in the joint portion (it is considered that the sealing property is low).

[Other Examples]
The present invention has the above-described embodiment as one basic technical idea, but the following modifications can be considered.
First, in the basic embodiment described above, the individual shapes of the claw 12 and the groove 13 are substantially isosceles trapezoidal shapes, but are not necessarily limited to this, for example, as shown in FIG. The shape may be circular (a circle larger than a semicircle). In short, various shapes can be adopted as long as the latching portion 14 that is hooked on the claw 12 and the groove 13 is formed. Incidentally, in the case of the embodiment shown in FIG. 6, the portion larger than the semicircle is the latching portion 14.

In the basic embodiment described above, the metal plate material used as the workpiece W is basically only one single plate, and both edge portions 11 of the single plate workpiece W are joined together. One pipe material 1 was obtained. However, the workpiece W does not necessarily need to be only a single plate, and a single pipe member 1 can be obtained using a plurality of metal plate members (blank materials). In this case, for example, as shown in FIG. 7A, a plurality of (two in this case) metal plate members are first joined in series, that is, a work W having a required size is first formed in a developed state. Then, it is possible to obtain a desired pipe material 1 as shown in FIG. 7B, for example, by sequentially performing preliminary bending (reducing bending of the claws 12), U bending, and O bending.
In addition, as shown in this FIG. 7, when connecting several metal plate material in series to make one workpiece | work W and rounding this to the said connection direction and obtaining the one pipe material 1, it is small size. Although it is effective in that a pipe material 1 having a large diameter can be obtained even from a metal plate material, a single pipe material 1 has a plurality of joint portions (seams) formed in the axial direction, and has some strength against internal pressure. It is thought that it falls.

Further, in the basic embodiment described above, the straight pipe material 1 in which the sizes (diameter dimensions) of both openings are substantially equal is taken as an example. I do not care.
In the above basic embodiment, the pipe member 1 has a substantially circular cross section. However, the present invention is not necessarily limited to this. For example, a rectangular cross section (so-called square pipe member) may be used. However, in the case of a square pipe material, it is preferable to place the joint (seam) in a plane portion (not in a side or a corner) so that an excessive load is not applied to the joint.

The pipe material of the present invention can be used as an outer cylinder of an exhaust gas catalytic device that purifies combustion gas discharged from various internal combustion engines, and is also applied to a communication pipe that connects a muffler or other silencer chamber. I can.
In addition, the pipe material of the present invention can be applied to pipe materials for all uses, such as a pipe material for making concrete struts (so-called independent foundations).

1 Pipe material 10 Mounting hole (hole)
10A small-diameter pipe (branch pipe)
11 Edge part 12 Claw (Fitting claw)
12a claw (fitting claw after reduced bending)
13 groove (receiving groove)
14 Hook

21 Female type (U bending)
22 Male (U bending)
25 Core (O-bending)
26 Receiving type (O-bending)
27 Pressing type (O-bending)

P1 Blank removal process P2 Pre-bending process (claw reduction bending process)
P3 U bending process P4 O bending process

U Exhaust silencer unit S Exhaust gas catalyst device S1 Outer cylinder S2 Honeycomb body (core piece)
G exhaust gas W work bu burr
ro Dare

Claims (9)

It is a method of obtaining a pipe material by joining the edges of a workpiece made of a metal plate material,
Prior to joining the edge portions, the workpiece is formed with a claw that fits into one edge portion, and a receiving groove that fits the claw is formed at the other edge portion, and the claw is fitted into the groove. To join the edges of the workpiece,
Also, the pipe material is characterized in that the claw and the groove are formed with a latching portion that is caught against this force when the pipe material after joining is about to spread along the outer surface. Manufacturing method.
In the initial flat state, the fitting claw is formed in a size larger than the receiving groove in the planar projection state,
Thereafter, prior to joining of the edge portions, the claw is three-dimensionally bent into a size smaller than the receiving groove in a planar projection state and is fitted into the groove in this state, and then flattened by crushing, The pipe material manufacturing method according to claim 1, wherein the outer shell is joined so as to be in close contact with the groove.
The metal plate material used as the workpiece is only one single plate, and both edge portions of the single plate workpiece are joined to obtain a single pipe material. Item 3. The method for producing a pipe material according to Item 1 or 2.
The fitting claw and the receiving groove are formed in an isosceles trapezoidal shape in a plan view in an initial flat state, and the isosceles trapezoidal leg portion functions as the latching portion. The manufacturing method of the pipe material of Claim 1, 2, or 3.
The workpiece is blanked from a metal plate having an appropriate plate thickness,
Further, when the mounting hole is opened in the radial direction of the pipe material as a finished product, the mounting hole is also opened at the same time when blanking the workpiece. The method for producing a pipe material according to 2, 3 or 4.
Regarding the joining of the edge portions, both burrs generated on the claw-side end surface and the groove-side end surface are positioned on the inner side and the outer side of the pipe material. The method for producing a pipe material according to 4 or 5.
In the pipe material, an appropriate fluid passes or is accommodated, and the edge portion is joined so that the fluid does not leak from the inside of the pipe to the outside of the pipe at the joining portion. The method for manufacturing a pipe material according to claim 1, 2, 3, 4, 5, or 6.
A pipe material manufactured by joining the edge portions of a workpiece made of a metal plate material, and the manufacturing method according to claim 1, 2, 3, 4, 5, 6 or 7 is applied to the pipe material. Pipe material characterized by that.
An exhaust gas catalyst device that purifies exhaust gas by a catalyst that is formed by providing a honeycomb body inside an outer cylinder body into which exhaust gas is fed, and is attached to the flow path surface,
An exhaust gas catalytic device characterized in that the pipe material according to claim 8 is applied to the outer cylindrical body.

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