CN112547872A

CN112547872A - Method for manufacturing tube structure

Info

Publication number: CN112547872A
Application number: CN202011023759.3A
Authority: CN
Inventors: 瀬直己; 寺泽太平; 奥田丞志; 藤泽秀行; 古山元士
Original assignee: Noritz Corp
Current assignee: Noritz Corp
Priority date: 2019-09-26
Filing date: 2020-09-25
Publication date: 2021-03-26
Also published as: JP7363015B2; JP2021049569A; US20210094084A1

Abstract

A method for manufacturing a pipe structure includes a pipe bending step in which a plurality of bending processes are performed in which a straight pipe (1) is partially wound around the circumferential surface of a rotating block (2) and bent, and a plurality of bent portions (10) are formed at the middle positions in the longitudinal direction of the pipe (1). When the final bending process is performed in the pipe bending process, the position of the rear end part (11b) of the pipe (1) is judged, and the y-direction relative position of the pipe (1) and the rotating block (2) is controlled based on the position of the rear end part (11b) so that the predetermined y-direction position of the rear end part (11b) after the bending process is aligned with the y-direction position of the front end part (11 a). According to the structure, the troublesome of cutting the two end parts (11a, 11b) of the pipe (1) after the bending processing can be eliminated, and the pipe structure body such as the winding-shaped pipe body (A) with the two end parts (11a, 11b) aligned can be manufactured with high productivity and in a proper mode.

Description

Method for manufacturing tube structure

Technical Field

The present invention relates to a method for manufacturing a tube structure, for example, a serpentine or spiral tube structure used as a component of a heat exchanger.

Background

As a tube structure used as a heat transfer tube of a heat exchanger, for example, a serpentine tube body a shown in fig. 1 is known. The serpentine tube body a is formed by forming a stainless steel tube 1 in a serpentine shape, and has a plurality of bent portions 10. The both end

portion vicinity regions

11A, 11B of the tube 1 are separated in the x direction and extend in the y direction intersecting the x direction.

As a method for producing the serpentine tube body a, for example, a method shown in fig. 12 is given. The manufacturing method includes a pipe forming and press cutting process S1, a pipe bending process S2, and a cutting and flash removing process S3.

Here, the tube forming and press cutting step S1 is a step of: as shown in fig. 13A, after a long and straight stainless steel pipe 1B is manufactured, the pipe 1B is cut into a pipe 1 having an appropriate length by press working.

The pipe bending step S2 is a step of performing bending processing a plurality of times to form a plurality of bent portions 10 at a middle portion in the longitudinal direction of the pipe 1 as shown in fig. 13B. This bending process is performed, for example, by bringing a part of the tube 1 into pressure contact with the circumferential surface of a rotating block (roll block) of the bending machine and simultaneously winding the tube 1. Deformed portions 18 are present at both

ends

11a, 11b in the longitudinal direction of the pipe 1, and the deformed portions 18 are formed by flattening due to cutting by the press working.

The cutting and deburring step S3 is a step of cutting both

end portions

11a and 11b of the pipe 1 and deburring the cut portions as shown in fig. 13C. The cutting is performed to remove the deformed portion 18 and to align the positions of the both

end portions

11a and 11b in the y direction. When the tube 1 is bent a plurality of times, an error (variation) occurs in the position of each bent portion 10, and the positions of the both

end portions

11a and 11b in the y direction become misaligned due to such accumulated errors as the entire tube 1, and a displacement of the dimension L1 is likely to occur. For this purpose, such a misalignment is eliminated from the cutting. As will be described later with reference to fig. 2A to 3, when the serpentine tube body a is used as, for example, a heat transfer tube of the heat exchanger HE, it is desirable to align the positions of both

end portions

11a, 11b in the y direction in advance.

As described below, there is still room for improvement in the above-mentioned conventional techniques.

In the above-described conventional technique, the cutting work is complicated because the both

end portions

11a and 11b of the pipe 1 are cut after the bending work of the pipe 1 is completed. As a result, the productivity of the meandering tube body a is poor, and the manufacturing cost is high, and there is room for improvement in this respect.

Unlike the above, for example, as shown in fig. 14, a member having no deformed portion 18 at both

end portions

11a and 11b may be used as the tube 1. However, if such a means is simply employed, the positions of both

end portions

11a, 11b in the y direction are shifted by an appropriate dimension L2. Therefore, in this case, a cutting process for aligning the positions of both

end portions

11a and 11b is also required. Therefore, the above-mentioned problems cannot be solved.

Documents of the prior art

Patent document

Patent document 1: japanese patent application laid-open No. 3824621

Patent document 2: japanese patent application laid-open No. 5822285

Patent document 3: japanese patent laid-open publication No. 2019-126830

Patent document 4: japanese laid-open patent publication No. 2012 and 135797

Disclosure of Invention

Problems to be solved by the invention

An object of the present invention is to provide a method for manufacturing such a tube structure: it is possible to eliminate the troublesome work of cutting or the like both end portions of the pipe after the bending work of the pipe, and to manufacture a pipe structure such as a meandering pipe body in which the both end portions are aligned with each other with high productivity and in a suitable manner.

Means for solving the problems

In order to solve the above problems, the present invention adopts the following technical means.

A method for manufacturing a pipe structure according to the present invention includes a pipe bending step of performing a bending process of bending a straight pipe by partially winding the straight pipe around a circumferential surface of a rotating block a plurality of times to form a plurality of bent portions at a middle portion in a longitudinal direction of the pipe, and is used for manufacturing a pipe structure in which: in the pipe bending step, a position of a rear end portion of the pipe is determined when the final bending process is performed, and a relative position of the pipe and the rotating block in the y direction is controlled based on the position of the rear end portion so that the position of the rear end portion after the bending process in the y direction is aligned with the position of the front end portion in the y direction.

The tube structure may be a serpentine tube or a spiral tube.

Preferably, in the operation of controlling the relative position of the tube and the turning block in the y direction based on the position of the rear end portion, a detection mechanism for detecting the rear end portion of the tube is used, and the tube is positioned by the detection mechanism so that the rear end portion of the tube is separated from the turning block by a predetermined dimension in the y direction.

Preferably, the predetermined dimension is a dimension in a y-direction from the turning block to the distal end portion of the tube in a state where the tube and the turning block are positioned in order to perform the first bending process on the tube.

Preferably, the method for manufacturing a tube structure of the present invention includes the steps of: when the pipe and the turning block are positioned to perform the final bending process, a projecting dimension in the y direction from the turning block to the tip end portion of the pipe is determined, and the predetermined dimension is a value corresponding to the projecting dimension.

Preferably, the linear tube is a tube having both longitudinal end portions cut by laser cutting.

Other features and advantages of the present invention will become more apparent from the following description of embodiments of the invention with reference to the accompanying drawings.

Drawings

Fig. 1 is a front view showing an example of a meandering tube body as a tube structure.

Fig. 2A is a top sectional view showing an example of a heat exchanger using the tube structure shown in fig. 1, fig. 2B is a front sectional view of fig. 2A, and fig. 2C is a right side sectional view of fig. 2B.

Fig. 3 is an exploded top cross-sectional view of fig. 2A.

Fig. 4 is an explanatory view showing an example of a series of operation steps of the method for producing a tube structure (a meandering tube body) according to the present invention.

Fig. 5A is an explanatory view showing the tube forming and press cutting process of fig. 4, and fig. 5B is an explanatory view showing the laser cutting process of fig. 4.

Fig. 6A is a schematic plan sectional view showing an example of a main part of a pipe bender used in the pipe bending process of fig. 4, and fig. 6B is a sectional view taken along line VIB-VIB in fig. 6A.

Fig. 7 is a schematic plan sectional view illustrating the operation of the pipe bender shown in fig. 6A and 6B.

Fig. 8A to 8G are explanatory views showing the pipe bending process of fig. 4.

Fig. 9A and 9B are front views showing another example of the meandering tube body.

Fig. 10A is a plan view showing an example of a spiral pipe body as a pipe structure, and fig. 10B is a cross-sectional view XB-XB of fig. 10A.

Fig. 11A to 11F are explanatory views showing a pipe bending process in the case of manufacturing the spiral pipe body shown in fig. 10A and 10B.

Fig. 12 is an explanatory diagram showing a series of operation steps in the prior art.

Fig. 13A to 13C are schematic explanatory views of the respective operation steps shown in fig. 12.

Fig. 14 is a front view showing another example of the conventional technique.

Detailed Description

Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

The target of the production method of the tube structure according to the present embodiment is the serpentine tube body a shown in fig. 1, as in the conventional technique described above. Thus, elements that are the same as or similar to the prior art are labeled with the same reference numerals as the prior art.

First, the serpentine tube body a will be described.

As described above, the serpentine tube body a is formed by winding the tube 1 made of, for example, stainless steel, and has a plurality of bent portions 10 each having a bending angle of 180 degrees and a plurality of linear portions 11 connected to each other by the plurality of bent portions 10. The end-

portion vicinity regions

11A and 11B of the tube 1 are separated in the x direction, which is the lateral width direction of fig. 1, and extend in the y direction. The x and y directions are directions intersecting each other.

The heat exchanger HE shown in fig. 2A to 2C is configured by a plurality of serpentine tubes a. More specifically, the heat exchanger HE houses the plurality of serpentine tubes a in the casing 7 in a state in which the plurality of serpentine tubes a are offset in the horizontal width direction and stacked in the vertical height direction. Both

end portions

11a and 11b of each of the serpentine tubes a are drawn out to the outside of the casing 7, and

headers

8a and 8b for water supply and hot water discharge are attached thereto. Hot water flows into or out of the serpentine tube body a through these

headers

8a and 8 b. The casing 7 is provided with an air supply port 70 and an exhaust port 71 for heating gas such as combustion gas generated by a burner, not shown. The serpentine tube body a functions as a heat transfer tube for recovering heat from the heating gas. The hot water flowing through the serpentine tube a is heated to generate hot water for hot water supply.

In the case of manufacturing the heat exchanger HE, as shown in fig. 3, the

headers

8a and 8b are attached to both

end portions

11a and 11b of each serpentine tube body a. In this case, it is required to align the positions of both

end portions

11a and 11b in the x direction in advance, and also align the positions of both

end portions

11a and 11b in the y direction. If the positions of the both

end portions

11a and 11b in the y direction are shifted, the hot water flowing manner in the

pipe headers

8a and 8b varies. Further, when the displacement in the y direction is large, the mounting of the

ferrules

8a and 8b may be hindered. The method of manufacturing a tubular structure according to the present embodiment can satisfy the above-described requirements. The contents of which are explained below.

In the method of manufacturing the tube structure (the meandering tube body a) according to the present embodiment, as shown in fig. 4, a tube forming and press-cutting process Sa, a laser cutting process Sb, and a tube bending process Sc are sequentially performed.

The tube forming and press-cutting step Sa is a step of manufacturing a long and straight tube 1A as shown in fig. 5A. The tube 1A is press-cut at both ends. Further, for example, a stainless steel member having a strip plate shape is rolled into a circular tube shape, and the butted portions are joined by laser welding or the like, whereby a pipe to be press-cut is manufactured (pipe manufacturing).

The laser cutting step Sb is a step of obtaining the tube 1 having the predetermined length La shown in fig. 5B by laser cutting the tube 1A as shown in fig. 5A. The laser cutting does not cause deformation such as a flat portion at both

end portions

11a and 11b of the tube 1. In addition, the flash is not easy to generate. Therefore, it is not necessary to perform a cutting step for removing the flat portion and burr removal. The length La of the tube 1 is the same as the overall length (flow path length) of the serpentine tube a to be finally obtained.

The pipe bending step Sc is a step of bending the pipe 1a plurality of times to form the entire pipe into a serpentine shape. For bending the pipe 1, a pipe bender PB shown in fig. 6A and 6B is used, for example.

The basic structure of the pipe bender PB is a conventionally known structure (for example, as described in patent documents 3 and 4), and includes a turning block 2, a pressing die 3, and a holding die 4. Further, the bender PB further includes a tube chuck 5 and a position sensor 6.

The turning block 2 is horizontally rotatable about the shaft portion 20, and has a pipe fitting recess 21 in the outer peripheral surface thereof for fitting the outer peripheral surface of the pipe 1. The pipe fitting recess 21 has a bent portion 21a bent in an arc shape within an angular range of 180 degrees, and linear portions 21b and 21c connected to both ends of the bent portion 21 a. A plurality of groove portions 22 are provided at appropriate intervals at the bent portion 21 a. The groove portion 22 is a portion for facilitating the compression deformation of the inner region of the bent portion 10 when the pipe 1 is bent.

The pressing die 3 is a block-shaped member having a series of tube fitting recesses 31 formed in the side surface thereof, and is located in the vicinity of the rotating block 2 so as to be capable of reciprocating in the x direction and the y direction. When the turning block 2 is rotated, the pressing die 3 presses the pipe 1 between the turning block 2 and the pressing die, and the pipe 1 can be bent and deformed.

The clamp die 4 is a portion for clamping the pipe 1 between the rotating block 2 and the clamp die 4 to perform a drawing operation of the pipe 1, and a pipe fitting recess 41 is provided on a side surface of the clamp die 4. By rotating the clamp die 4 together with the rotary block 2 in the direction of arrow Na in fig. 6A about the shaft portion 20, the pipe 1 can be partially wound around the inner surface of the bent portion 21a of the rotary block 2 and bent as shown in fig. 7.

In fig. 6A, the pipe chuck 5 can feed the pipe 1 to the rotary block 2 side by freely clamping or not clamping the pipe 1 and moving forward to the rotary block 2 side while clamping the pipe 1. The pipe chuck 5 can also rotate the pipe 1 by rotating around the axial center of the pipe 1 (rotation in the direction of arrow Nb in fig. 6A) with the pipe 1 being held therebetween.

The position sensor 6 is, for example, a light-reflecting optical sensor including a light-emitting element and a light-receiving element, and is capable of detecting the position of the edge of the rear end portion 11b of the tube 1. In the present embodiment, when the edge of the rear end portion 11b reaches the front surface of the position sensor 6 when the pipe 1 is fed to the rotary block 2 side, the position sensor 6 can detect this. The position sensor 6 corresponds to an example of "detection means for detecting the rear end portion" in the present invention. As the position sensor 6, a light transmission type may be used instead of the light reflection type, and a sensor other than an optical type may be used.

The pipe bending step Sc is performed in the process shown in fig. 8A to 8G. The following description is made.

First, as shown in fig. 8A, it is arranged to sandwich the tube 1 between the pressing die 3 and the clamping die 4 and the turning block 2 each other. At this time, (the edge of) the leading end portion 11a of the tube 1 and the mutual dimension Lb in the y direction of the rotating block 2 are defined in advance as a predetermined dimension. In this state, as shown in fig. 8B, the first bending process is performed by rotating the clamp die 4 and the rotary block 2 in the direction of arrow Na, and thereby the bent portion 10 is formed.

Next, as shown in fig. 8C, the tube chuck 5 is rotated in the arrow Nc direction to change the orientation of the tube 1, and the tube chuck 5 is advanced toward the turning block 2. The holding die 4 and the turning block 2 are returned to the original positions without interfering with the pipe 1. This makes it possible to prepare for the second bending process as shown in fig. 8D. Then, as shown in fig. 8E, the second bending process is performed by rotating the holding die 4 and the rotating block 2 again in the arrow Na direction, thereby forming a second bent portion 10.

As can be understood from the first bending and the second bending, the bending step Sc repeats the following operations: after the tube 1 is fed to the rotary block 2 side while changing the direction of the tube 1, the clamp die 4 and the rotary block 2 are rotated to bend the tube 1. This produces a serpentine tube body a' shown in fig. 8F. The meandering tube a' is a tube that has not been subjected to final bending.

When the pipe 1 is finally bent, control is performed to position the pipe 1 in advance so that the edge of the rear end portion 11b of the pipe 1 is positioned on the front surface of the position sensor 6, and detection is performed by the position sensor 6. Thereby, the dimension Lc from the edge of the rear end portion 11b to the center of the rotating block 2 is accurately defined as a predetermined dimension. This dimension Lc is the same as, for example, a dimension Lb from the edge of the distal end portion 11a to the center of the rotating block 2 in the initial setting state shown in fig. 8A.

In the set state, as shown in fig. 8G, the holding die 4 and the turning block 2 are rotated to perform the final bending process. The meandering tube body a shown in fig. 1 is thus obtained, but based on the fact that the relative positioning in the y direction of (the edge of the rear end portion 11b of) the tube 1 and the turning block 2 shown in fig. 8F is achieved, the positions in the y direction of both

end portions

11a, 11b (the front end portion 11a and the rear end portion 11b) of the meandering tube body a are aligned.

According to the manufacturing method described above, for example, as shown in fig. 9A, the last folded portion 10(10B) is located at a position lower than the folded portions 10 of the other intermediate portions by an appropriate dimension Ld, or as shown in fig. 9B, the last folded portion 10(10B) is located at a position higher than the folded portions 10 of the other intermediate portions by an appropriate dimension Le. However, the positions of both

end portions

11a, 11b in the y direction are appropriately aligned, and a serpentine tube body a preferable in the case of manufacturing the heat exchanger HE shown in fig. 2A to 2C is obtained. When the positions of the both

end portions

11a, 11b in the y direction are misaligned, the length adjustment by cutting the both

end portions

11a, 11b is necessary as a means for eliminating the misalignment, but this is not necessary according to the present embodiment. Therefore, the productivity of the heat exchanger HE can be improved, and the manufacturing cost can be reduced.

Fig. 10A and 10B show a spiral pipe body Aa as another example of the pipe structure of the present invention.

The spiral pipe body Aa has a plurality of bent portions 10 formed at 90-degree bending angles at intermediate positions in the longitudinal direction of the pipe 1, and the pipe 1 is formed in a substantially rectangular spiral shape in a front view. The

regions

11A and 11B near both ends of the spiral pipe body Aa are separated in the x direction and extend in the y direction. The spiral pipe body Aa can also be used as a heat transfer pipe of a heat exchanger.

The spiral pipe body Aa can be manufactured through, for example, a bending process shown in fig. 11A to 11F. Fig. 11A to 11F schematically show the positional relationship between the tube 1 and the turning block 2, and other components of the tube bender are omitted.

First, as shown in fig. 11A, in a state where the tube 1 is along the rotary block 2, the tube 1 is bent by 90 degrees in the arrow Nd direction as shown in fig. 11B. Next, after the pipe 1 is fed out by a predetermined dimension in the arrow Ne direction as shown in fig. 11C, the pipe 1 is bent again by 90 degrees as shown in fig. 11D. By repeating such steps, a spiral pipe body Aa' in the form shown in fig. 11E is obtained.

The spiral pipe body Aa ' is a member immediately before the final bending process is performed, and before the final bending process is performed thereafter, the edge of the rear end portion 11b of the pipe 1 is detected by the position sensor 6, and the position of the pipe 1 is controlled so that a dimension Lc ' from the edge of the rear end portion 11b to the center of the rotating block 2 coincides with a dimension Lb ' from the edge of the front end portion 11A to the center of the rotating block 2 as shown in fig. 11A, for example. Then, as shown in fig. 11F, when the final bending process is performed on the tube 1, the positions of the front end portion 11a and the rear end portion 11b of the tube 1 in the y direction are aligned.

The present invention is not limited to the above-described embodiments. The specific structure of each operation step of the method for producing a tubular structure of the present invention can be variously modified within the scope intended by the present invention.

In the above-described embodiment, as means for aligning the position of the rear end portion 11b of the tube 1 in the y direction and the position of the front end portion 11a in the y direction after the final bending process of the tube 1, for example, the dimension Lc shown in fig. 8F is the same as the dimension Lb of fig. 8A, but the present invention is not limited thereto. In the present invention, for example, the following means can be adopted: in the state shown in fig. 8F, the position of the distal end portion 11a is detected by an appropriate sensor (e.g., the sensor 6A indicated by the imaginary line), the projecting dimension Lf in the y direction from the rotary block 2 to the distal end portion 11a is determined, and the relative positioning control of the pipe 1 and the rotary block 2 is realized such that the dimension Lc and the value corresponding to the projecting dimension Lf (e.g., the value obtained by adding the projecting dimension Lf and the arc length of the bent portion 10) are the same.

The specific number and bending angle of the bent portions formed in the tube are not limited. In the above-described embodiment, the bent angle of the bent portion 10 of the meandering tube body a is 180 degrees, and the bent angle of the bent portion 10 of the spiral tube body Aa is 90 degrees, but other bent angles may be used. The specific bending radius of the pipe, the size and material of the pipe to be bent, and the like are not limited. Instead of a circular tube, an elliptical tube can also be used.

The tube structure manufactured according to the present invention is suitable for use as a heat transfer tube of a heat exchanger, but can also be applied to other applications. The tube structure is not limited to a serpentine tube or a helical tube.

Claims

1. A method for manufacturing a tube structure is provided,

the manufacturing method comprises a pipe bending step of performing bending processing of partially winding a straight pipe around the circumferential surface of a rotating block and bending the pipe a plurality of times to form a plurality of bent portions at the middle part of the pipe in the longitudinal direction,

the manufacturing method is used for manufacturing the pipe structure: a front end region of the tube on a bend start side and a rear end region of the tube on a bend end side are separated in a predetermined x direction and extend in a y direction intersecting the x direction,

in the pipe bending step, the position of the rear end portion of the pipe is determined when the final bending process is performed, and the y-direction relative position between the pipe and the rotating block is controlled based on the position of the rear end portion so that the y-direction position of the rear end portion after the bending process is aligned with the y-direction position of the front end portion.

2. The method of manufacturing a tubular structure according to claim 1,

the tube structure is a serpentine tube body.

3. The method of manufacturing a tubular structure according to claim 1,

the tubular structure is a helical tubular body.

4. The method of manufacturing a tubular structure according to claim 1,

in the operation of controlling the relative position of the tube and the turning block in the y direction based on the position of the rear end portion, a detection mechanism for detecting the rear end portion of the tube is used, and the tube is positioned by the detection mechanism so that the rear end portion of the tube is separated from the turning block by a predetermined dimension in the y direction.

5. The method of manufacturing a tubular structure according to claim 4,

the predetermined dimension is a dimension in the y direction from the turning block to the tip end portion of the tube in a state where the tube and the turning block are positioned in order to perform the first bending process on the tube.

6. The method of manufacturing a tubular structure according to claim 4,

the method for manufacturing the pipe structure comprises the following steps: determining a projecting dimension in a y-direction from the turning block to the tip end portion of the tube when the tube and the turning block are positioned to perform the final bending process,

the predetermined size is a value corresponding to the protrusion size.

7. The method of manufacturing a tubular structure according to claim 1,

as the linear tube, a tube having both longitudinal end portions cut by laser was used.