JP6605325B2 - Tubular structure - Google Patents

Description

  The present invention relates to a tubular structure.

Conventionally, ductile cast iron pipes are often used as tubular structures such as water pipes. Since the ductile cast iron pipe is made of cast metal, it has a high degree of freedom in shape. For this reason, a wide variety of joints exist and are used in the right place for the right material.
On the other hand, stainless steel (SUS) is also present as a tubular structure such as a water pipe, but it is limited to a specific application because it is not easy to process the joint. However, the SUS pipe has a longer service life than the ductile cast iron pipe. Furthermore, problems such as red water and blue water are unlikely to occur, and stress corrosion cracking does not occur in a room temperature environment, so the running cost is low. For this reason, use of the SUS pipe | tube for various uses is calculated | required in the future.

Since the tubular member made of SUS has a lower degree of freedom in shape than a ductile cast iron pipe, it is difficult to connect the same as a ductile cast iron pipe.
For this reason, as a method for connecting the tubular structures made of SUS, conventionally, a convex portion is formed on the outer periphery of the tubular member by welding a square ring to the outer periphery of the tubular member, and the tube ends of the two tubular structures are connected to each other. There is a method in which the housings are arranged on the outer periphery (see Patent Document 1).

  In addition, a retaining member is attached to the outer periphery of the tubular structure, the retaining member is reduced in diameter by a cap nut having a tapered surface, and the pipe ends are joined by biting into the outer periphery of the annular structure of the retaining member. There is also a method (see Patent Document 2).

  Furthermore, there is also a method of connecting tubes using a lock ring (see Patent Document 3). In Patent Document 3, a groove provided on the outer periphery of one tube end of two tubular structures to be connected is provided with a lock ring that is elastically deformed on the wide diameter side by cutting one portion in the circumferential direction. Fit. The tube end of the other tubular structure is provided with a special shape for receiving the tube end on one side where the lock ring is fitted. The tubular structure is connected by disposing a push ring at a portion opposite to the tube end with respect to the lock ring, and connecting the push ring and the special shape portion with the lock ring interposed therebetween.

Utility Model Registration No. 3171067 JP 2003-254476 A JP 2008-309276 A

  The tubular structure may be cut and connected to a predetermined length at a construction site, and the square ring is attached to the cut pipe end. For this reason, in Patent Document 1, the square ring is welded to the tubular member after cutting at the construction site. However, it is difficult to guarantee the quality of welding at the construction site.

  In Patent Document 2, since welding is not used, processing at a construction site is possible. However, the annular structure is fixed by reducing the diameter of the retaining member with a cap nut, and the diameter of the retaining member is also limited, and it cannot be said that the ability to prevent extraction is sufficient.

  Also in Patent Document 3, since welding is not used, processing at a construction site is possible. Moreover, since the lock ring is attached, it has the extraction prevention capability higher than patent document 2. FIG. However, since the lock ring is only fitted into a groove provided on the outer periphery of the tubular member by elastic deformation, the fixing force to the tubular member is not so strong. Furthermore, the shape of one end of the tubular structure is complicated, and the number of parts is large. Further, in a cast iron pipe (for example, thickness 7.5 mm) having a large pipe thickness, a sufficient groove depth for fitting the lock ring can be secured, but a stainless steel pipe thickness (for example 3.0 mm) is sufficient. It is difficult to process a deep groove.

  In view of these prior arts, an object of the present invention is to provide a tubular structure that can be processed at a construction site and has a high ability to prevent extraction when connected even if the wall thickness is thin. To do.

The present invention includes a tubular member having an annular recess formed at a tube end, and two outer surfaces perpendicular to the axis of the tubular member, and a fitting ring that is pressed and fixed to the outer periphery of the annular recess. When,
It is a tubular structure provided with.

  The fitting ring is divided into a plurality of arc-shaped members, and the arc-shaped members are connected to each other by a connecting member, and the fitting ring is pressed and fixed to the inner periphery of the fitting ring in a connected state. The arcuate member is shorter than the outer periphery of the annular recess, and the arcuate member before connection is disposed on the outer periphery of the annular recess of the tubular member, and by connecting the arcuate members to each other by the connecting member, the tubular member is It is preferable to press and fix to the outer periphery of the annular recess.

  The annular recess has two inner surfaces perpendicular to the axis and a bottom surface parallel to the axis, the fitting ring is a square ring, the two inner surfaces of the annular recess and the fitting It is preferable that the two outer surfaces of the insertion ring substantially contact each other, and the bottom surface of the annular recess and the inner peripheral surface of the fitting ring contact each other.

  The depth of the annular recess is preferably less than or equal to one half of the radial thickness of the tubular member.

One of the tube end portions of the tubular member is an insertion port, and the other is a receiving port having a larger diameter than the insertion port,
It is preferable that the annular recess and the fitting ring are provided on at least one side of the insertion port or the receiving port.

  The tubular member and the fitting ring are preferably formed of stainless steel.

  According to the present invention, it is possible to provide a tubular structure that can be processed at a construction site and has a high ability to prevent extraction when connected even when the wall thickness is thin.

It is sectional drawing which shows the state which connected two tubular structures concerning embodiment using the housing. It is a fragmentary sectional view of the tubular member in the state where the fitting ring is not attached. It is the fragmentary sectional view which showed the state which mounted | wore with the fitting ring to the tubular member 1 of the state of FIG. It is a figure explaining a fitting ring, (a) is one perspective view divided | segmented, (b) is the other perspective view divided | segmented, (c) shows the state which couple | bonded one and the other. The housing is shown in a sectional view seen from the direction of arrow B in FIG. It is a photograph of the principal part of a tubular structure.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a cross-sectional view showing a state in which two tubular structures 100 according to the embodiment (100A, 100B) are connected using a sealing rubber 40 and a housing 30. FIG. Although the tubular structure 100 of embodiment is used for the pipe joint part for fluid supply, it is not limited to this.

  The tubular structure 100 of the embodiment includes a tubular member 1, a small-diameter side insertion ring 13 </ b> A disposed on the outer periphery of the tubular member 1, and a large-diameter side insertion ring 13 </ b> B.

The tubular member 1 is constituted by, for example, a steel pipe made of stainless steel (SUS304). The tubular member 1 has a small diameter portion 10 and a large diameter portion 20 provided continuously from one end of the small diameter portion 10.
The end of the small diameter portion 10 on the side that is not continuous with the large diameter portion 20 serves as the insertion opening 11 connected to the large diameter portion 20 of the other tubular member 1. A small-diameter annular recess 12 </ b> A is formed near the end of the insertion slot 11.
The end of the large diameter portion 20 on the side that is not continuous with the small diameter portion 10 serves as a receiving port 21 connected to the insertion port 11 of the other tubular member 1. In the vicinity of the end of the receiving port 21, a large-diameter annular recess 12 </ b> B is formed.

  Next, the small-diameter-side annular recess 12A and the large-diameter-side annular recess 12B will be described. In the following description, near the end of the small-diameter-side annular recess 12A and the receiving port 21 provided near the end of the insertion slot 11. The provided large-diameter-side annular recess 12B is the same as the one other than the diameter, and therefore will be described as the annular recess 12 without distinguishing both unless it is necessary to distinguish them.

FIG. 2 is a partial cross-sectional view of the tubular member 1 in a state where the fitting ring 13 is not attached.
As illustrated, an annular recess 12 is formed on the outer surface of the tubular member 1 by cutting recess processing.
The width t1 of the annular recess 12 is 8 mm in this embodiment.
The depth t2 of the annular recess 12 is preferably not more than half of the thickness around the annular recess 12 in the tubular member 1 (thickness of the tubular member 1 in the state of a raw tube) t3 in terms of strength. In the embodiment, the thickness t3 around the annular recess 12 is 3 mm, and the cutting depth is 1.0 to 1.5 mm.

The small diameter side fitting ring 13 </ b> A is inserted into the small diameter side annular recess 12 </ b> A on the outer periphery of the small diameter portion 10. The large diameter side fitting ring 13 </ b> B is inserted into the large diameter side annular recess 12 </ b> B on the outer periphery of the large diameter portion 20.
Hereinafter, since the small-diameter side insertion ring 13A inserted into the small-diameter side annular recess 12A and the large-diameter side insertion ring 13B inserted into the large-diameter side annular recess 12B are also the same except for the diameter, it is necessary to distinguish below. Except for the case where there is, it will be described as the fitting ring 13 without distinguishing both.

FIG. 3 is a partial cross-sectional view showing a state in which the fitting ring 13 is attached to the tubular member 1 in the state of FIG.
The fitting ring 13 is divided into two arc-shaped members. 4A and 4B are views for explaining the fitting ring 13, wherein FIG. 4A is a perspective view of one arcuate member 13a divided into two parts, and FIG. 4B is a perspective view of the other arcuate member 13b divided into two parts. (C) shows a state in which the arcuate member 13a and the arcuate member 13b are coupled.

The fitting ring 13 is manufactured, for example, by cutting a roughly cast product. Therefore, the fitting ring 13 can be manufactured with higher accuracy than the case where it is manufactured by casting.
Although the fitting ring 13 of the embodiment is divided into two, it is not limited to this, and may be divided into three or more.
Bolt holes 13aa are formed at both ends of the arcuate member 13a.
Both end portions of the arcuate member 13b are cut away leaving a wall portion 13ba of a predetermined width, and the wall portion 13ba is provided with an insertion hole 13bb through which a bolt is inserted.

  As shown in FIG. 4C, the fitting ring 13 is configured so that the ends of the arcuate member 13a and the arcuate member 13b face each other, and the bolt 14 is inserted from the insertion hole 13bb of the arcuate member 13b. It is integrally formed by screwing into the bolt hole 13aa of the arc-shaped member 13a.

The inner circumference of the fitting ring 13 in the connected state is slightly shorter than the outer circumference of the annular recess 12 to which the fitting ring 13 is attached. That is, the fitting ring 13 has a fastening allowance with the bottom (outer surface) of the annular recess 12.
With this tightening allowance, the arc-shaped member 13a and the arc-shaped member 13b are arranged on the outer periphery of the annular recess 12, the bolt 14 is tightened, and the arc-shaped member 13a and the arc-shaped member 13b are connected to each other. The outer periphery of the annular recess 12 is pressed and fixed.

  The fitting ring 13 has two side surfaces 13c and 13d parallel to each other along a plane perpendicular to the axis A of the tubular member 1 as shown in FIG. However, the side surfaces 13c and 13d may not be strictly perpendicular to the axis A.

  The fitting ring 13 is a rectangular ring having a rectangular cross section. In the embodiment, the width T1 (the distance between the side surface 13c and the side surface 13d, the axial width and thickness of the tubular member 1) is the same as that of the annular recess 12. It is substantially equal to the width, and in this embodiment, it is 8 mm and is fitted into the annular recess 12 without a gap. Moreover, the protrusion height T3 which protrudes outside from the outer periphery of the tubular member 1 of the fitting ring 13 is 8 mm. That is, the radial thickness T2 of the fitting ring 13 is adjusted according to the depth t2 of the annular recess 12.

The protrusion height T3 projecting outward from the outer periphery of the tubular member 1 of the fitting ring 13 is a clearance between the inner peripheral surface of the housing 30 (the inner peripheral surface of the portion other than the groove) and the outer peripheral surface of the tubular member 1. 3 mm or more larger than 2.5 mm which is the maximum value of T4 (shown in FIG. 1) is preferable.
The protrusion height T3 of the fitting ring 13 is preferably equal to or less than the distance T5 between the bottoms of grooves 36 and 38 (described later) provided in the housing 30 and the outer peripheral surface of the tubular member 1.
In this embodiment, since the height T3 of the fitting ring 13 is 8 mm and the depth t2 (see FIG. 2) of the annular recess 12 is 1.5 mm, the protruding height T2 is 9.5 mm.

The material of the fitting ring 13 is stainless steel (SUS304), for example. The material of the fitting ring 13 is not limited to stainless steel, but the hardness of the fitting ring 13 is preferably at least as hard as the housing 30 and the annular recesses 12 and 22 (tubular member 1). .
If the fitting ring 13 is softer than the housing 30 and the annular recesses 12 and 22, the fitting ring 13 is plastically deformed when a force is applied in a direction in which the two tubular structures 100A and 100B to be connected are separated from each other. There is a possibility that the anti-pipe prevention performance cannot be ensured.

A sealing rubber 40 is attached to the outer periphery of the connecting portion of the two tubular structures 100.
The sealing rubber 40 has two inner peripheral surfaces 41 and 42 facing the outer peripheral surface of the tubular member 1, and has a substantially L shape in the cross section shown in FIG. However, it is not limited to this, For example, a U-shape may be sufficient.
The diameter of one inner peripheral surface 41 is slightly smaller than the diameter of the outer peripheral surface of the small-diameter portion 10, and when it is disposed on the outer peripheral surface of the small-diameter portion 10, it elastically deforms and comes into close contact with the outer peripheral surface of the small-diameter portion 10.
The other inner peripheral surface 42 is slightly smaller than the diameter of the outer peripheral surface of the large-diameter portion 20 and is elastically deformed when it is disposed on the outer peripheral surface of the large-diameter portion 20 so as to be in close contact with the outer peripheral surface of the large-diameter portion 20.

A housing 30 is attached to the outer peripheral side of the sealing rubber 40.
FIG. 5 is a cross-sectional view seen from the direction of arrow B in FIG.
In this embodiment, the housing 30 is made of cast iron defined by JIS G 5502 FCD450. Since the housing 30 is made of cast iron as described above, the dimensional tolerance is larger than that of the fitting ring 13, and the maximum between the inner peripheral surface of the housing 30 (the portion where no groove is provided) and the outer peripheral surface of the tubular member 1. The clearance is about 2.5 mm as described above.

As shown in FIG. 5, the housing 30 includes two semicircular members 30 </ b> A and 30 </ b> B. Each of the semicircular members 30 </ b> A and 30 </ b> B includes a semicircular ring portion 31 along the outer periphery of the tubular member 1 and two flange portions 32 extending radially outward from both ends of the semicircular ring portion 31.
Each flange portion 32 is provided with a hole 33. When the semicircular members 30A and 30B are arranged on the outer periphery of the tubular structure 100 and the flange portion 32 of the semicircular member 30A and the flange portion 32 of the semicircular member 30B are opposed to each other, the holes 33 provided in both flange portions 32 are provided. Penetrates.
Bolts 34 are inserted into the holes 33, and nuts 35 are screwed onto the ends of the screw portions of the bolts 34. By tightening the nut 35, the two semicircular members 30A, 30B cover the outer periphery of the tubular structure 100, and the two tubular structures 100 are connected.

As shown in FIG. 1, on the inner peripheral surface of the housing 30, an annular groove 36 that covers the outer periphery of the large-diameter side fitting ring 13 </ b> B of the receiving port 21, an annular groove 37 that fits the sealing rubber 40, and an insertion port 11 and an annular groove 38 that covers the small-diameter side fitting ring 13A.
The width of the annular groove 36 has a slight gap so that the large-diameter side fitting ring 13B can be inserted.
The width of the annular groove 38 is considerably larger than the width of the small diameter side fitting ring 13A. The reason is that the tubular structure 100 is required to have a stretchability of about plus or minus 1.0% with respect to the tube length, for example, according to the standard of JWWA G 113. is there.

(Method for producing tubular structure)
On the outer periphery of the tubular member 1 in a state where the annular recess 12 is not formed, the annular recess 12 is manufactured by cutting as shown in FIG.

  Next, as shown in FIG. 4 (c), one arcuate member 13 a and the other arcuate member 13 b of the two-part fitting ring 13 are arranged on the outer periphery of the annular recess 12, and are mutually connected with bolts 14. tighten. Thereby, the fitting ring 13 presses the outer surface of the tubular member 1, and the fitting ring 13 is pressed and fixed to the annular recess 12 of the tubular member 1 as shown in FIG. 3. FIG. 6 is a photograph of the main part of the tubular structure 100 in a state where the fitting ring 13 is pressed and fixed to the annular recess 12 of the tubular member 1.

(Method for connecting tubular structures)
A method for connecting the tubular structure 100 will be described.
First, the sealing rubber 40 is inserted into the connecting side of the insertion port 11 or the receiving port 21 in one of the two tubular structures 100 to be connected.
Next, the connecting side of the insertion port 11 or the receiving port 21 in the other of the two tubular structures 100 is inserted into the sealing rubber 40.

The semicircular members 30 </ b> A and 30 </ b> B of the housing 30 are arranged on the outer periphery of the tubular structure 100.
At this time, the small-diameter side insertion ring 13A enters the annular groove 38, the sealing rubber 40 enters the annular groove 37, and the large-diameter side insertion ring 13B enters the annular groove 36.
The flange portion 32 of the semicircular member 30 </ b> A and the flange portion 32 of the semicircular member 30 </ b> B are opposed to each other, a bolt 34 is inserted into the hole 33 provided in both flange portions 32, and a nut 35 is inserted at the tip of the screw portion of the bolt 34. Screw together.
By tightening the nut 35, the two semicircular members 30A, 30B cover the outer periphery of the tubular structure 100, and the two tubular structures 100 are connected.

(Effect of tubular structure of embodiment)
The effect of the tubular structure 100 of embodiment is demonstrated.
Table 1 shown below is a table showing separation prevention loads of the tubular structure 100 of the embodiment and the tubular structure of the comparative form. Here, the detachment load is the maximum load that can be withstood when two tubular structures are connected using a housing and a force is applied in a direction in which both tubular structures are separated from each other.

The results of this embodiment are shown in (1) to (3). Further, (4) to (6) are comparative forms, and (4) is a fitting ring welded to the outer periphery of the tubular member described in Patent Document 1 described above. (5), as described in Patent Document 2 described above, the retaining member is attached to the outer periphery of the tubular structure, and the retaining member is reduced in diameter by a cap nut having a tapered surface. The tube ends are joined together by biting into the outer periphery of the annular structure. (6) connects the pipes by fitting a lock ring, which is a retaining member, into a groove formed on the outer peripheral surface of the pipe as described in Patent Document 3 described above.
As the tubular member, a nominal diameter of 80A (actual diameter: φ89.1 mm, pipe thickness: 3.0 mm) was used.

As shown in Table 1, the largest separation load is the largest in the comparative form (4). (4) is a fitting ring attached to the pipe end by welding.
Here, the length of the tubular structure is adjusted at the construction site, and the tubular structure is cut. Then, since the pipe end position is determined at the construction site, it is necessary to perform the work of welding the fitting ring to the pipe end at the construction site. However, processing at the construction site is not preferable from the viewpoint of quality assurance. Therefore, it is difficult to realistically implement the comparison form (4).

  On the other hand, the tubular structures of the comparative forms (5) and (6) can have length nodes at the construction site, but this embodiment is compared with these (5) and (6), The maximum detachment prevention load is large, indicating a value close to (4).

As described above, according to the present embodiment, the fitting ring 13 is fitted into the annular recess 12 with a tightening margin so that the groove depth is as high as possible in a stainless steel pipe having a thickness of about 3.0 mm. It is possible to provide a joint structure that can provide a pull-out prevention capability of 160 kN that is twice the nominal diameter 80A and less than 3 times 240 kN at 0.0 mm, 1.2 mm, and 1.5 mm.
Moreover, since welding is not used, processing at a construction site is also possible.

  As mentioned above, although embodiment of this invention was described, it is not limited to this. Although the tubular structure 100 of the embodiment has been described with respect to the form in which the annular recess and the fitting rings 13A and 13B are arranged on both sides of the insertion opening 11 and the receiving opening 21, the present invention is not limited thereto. May be provided with an annular recess and fitting rings 13A and 13B, and the fitting ring 13A and 13B may be welded to the tubular member 1 without providing an annular recess at the receiving port.

DESCRIPTION OF SYMBOLS 1 Tubular member 10 Small diameter part 11 Insertion port 12 Annular recessed part 12A Small diameter side annular recessed part 12B Large diameter side annular recessed part 13 Insertion ring 13c Side surface 13d Side surface 13A Small diameter side insertion ring 13B Large diameter side insertion ring 30 Housing 36 Annular groove 37 Annular groove 38 Annular groove 40 Sealing rubber 41 Inner peripheral surface 42 Inner peripheral surface 100 Tubular structure

Claims (4)

A tubular member having an annular recess formed at the end of the tube;
A fitting ring having two outer surfaces perpendicular to the axis of the tubular member and pressed and fixed to the outer periphery of the annular recess,
The fitting ring is
Divided into two arcuate members,
Bolt holes are formed at both ends of one arcuate member,
Both ends of the other arcuate member are cut away leaving a wall portion of a predetermined width, and the wall portion is provided with an insertion hole for inserting a bolt,
The ends of the one arcuate member and the other arcuate member are opposed to each other, a bolt is inserted from the insertion hole of the other arcuate member, and the bolthole of the one arcuate member is inserted. By being screwed together, they are connected to each other,
One of the tube end portions of the tubular member is an insertion port, and the other is a receiving port having a larger diameter than the insertion port,
The annular recess is provided in each of the insertion port and the receiving port,
A small-diameter side insertion ring is attached to the annular recess on the insertion side,
A large-diameter side fitting ring is attached to the annular recess on the receiving side,
The inner peripheral surface is connected by a housing made of cast iron provided with an annular groove covering the outer periphery of the large-diameter side fitting ring and an annular groove covering the outer periphery of the small-diameter side fitting ring,
The tubular member is formed of stainless steel, and the fitting ring is formed of stainless steel having a hardness equal to or higher than that of the housing and the annular tubular member.
Tubular structure. The inner circumference of the fitting ring in a connected state is shorter than the outer circumference of the annular recess to which the fitting ring is pressed and fixed.
The arc-shaped member before connection is arranged on the outer periphery of the annular recess of the tubular member, and the fitting ring is pressed and fixed to the outer periphery of the annular recess by connecting the arc-shaped members to each other by the connection member.
The tubular structure according to claim 1. The annular recess has two inner surfaces perpendicular to the axis, and a bottom surface parallel to the axis.
The fitting ring is a square ring,
The two inner side surfaces of the annular recess and the two outer surfaces of the fitting ring are substantially in contact with each other, and the bottom surface of the annular recess and the inner peripheral surface of the fitting ring are in contact with each other,
The tubular structure according to claim 1 or 2. The depth of the annular recess is not more than one half of the radial thickness of the tubular member.
The tubular structure according to any one of claims 1 to 3.