JP3677431B2 - Fixing structure of pipe end anticorrosion core - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a pipe end anticorrosion core fixing structure of a metal pipe insertion opening constituting a pipeline such as a water pipe, and more particularly, a random pipe (cut pipe generated when cut in the middle of a metal pipe for dimensional adjustment at the time of site installation. ) End tube end anticorrosive core fixing structure.
[0002]
[Prior art]
Conventionally, for example, when a ductile cast iron pipe is buried in the ground and a pipe line is laid, the entire pipe is protected against corrosion by painting or lining, and as shown in FIG. In general, the insertion port 2a of the succeeding tube 2 is inserted and joined. At this time, as shown in the figure, in the NS type joint imparted with earthquake resistance, the lock ring 3 is provided on the inner surface of the receiving port 1a via the rubber centering ring 3a, as shown by the chain line in FIG. The lock ring 3 is inserted and the opening ring 4 gets over and the insertion opening 2a is inserted. In the figure, 4a is an annular fitting groove of the insertion port ring 4, 5 is a packing, and 6 is a lining.
[0003]
In the laying of this pipe line, there is a case where the pipe 2 is not always joined only by a fixed size (standard) pipe, but the pipe 2 may be cut and joined so as to have a predetermined length at the construction site. . When the tube 2 is cut in this way, the coating is peeled off and the background is exposed on the tube end surface that becomes the cut surface, so that the anticorrosion function is impaired and red water or the like is generated. Therefore, in general, an anticorrosion coating is applied again to the end face after the cut tube to prevent corrosion. However, when reapplying, it takes time to dry in cold weather, and workability is reduced, and it is difficult to place paint on the edge part, and the anticorrosion performance is inferior to factory-painted products. In places where running water does not stop completely, there is a problem that it is difficult to apply such as difficult to apply.
[0004]
For this reason, there exists a method of sealing the exposed part using the anticorrosion core 7, as shown in FIG. This anticorrosion core 7 is made of resin, rubber or the like having a certain degree of elasticity, and is attached over the entire circumference of the circle so as to cover the end face of the cut tube from the inner and outer faces of the opening 2a, thereby preventing water from entering the end face. The anticorrosion performance of the edge portion, which is difficult with the anticorrosion paint, is improved.
[0005]
Further, since the NS type pipe has its tapered surface 2b in contact with the lock ring 3 at the time of joint joining, the anticorrosive paint may be peeled off at the site construction and a sufficient anticorrosion effect may not be obtained. For this reason, covering the taper surface 2b with the core 7 having high tear resistance is an effective anticorrosion means. Since the anticorrosion core 7 is made of an elastic body such as rubber, it is held by an elastic force. However, as a method of fixing it more reliably, it is disclosed in JP-A-7-253189, and as shown in FIG. There is a type in which a fixing ring 8 having a split opening in one direction is fitted to the inner cylindrical portion of the anticorrosion core 7 and is fixed by a diameter expanding force from the inner surface (see FIG. 4). In FIG. 20, 9 is an annular fitting groove of the fixing ring 8.
[0006]
[Problems to be solved by the invention]
However, since the fixing ring 8 fixes the anticorrosion core 7 only with a large opening force, if it is used for a long time, the expansion force is attenuated due to aging deterioration of the material of the fixing ring 8 and the anticorrosion function. However, there is a limit to maintaining the system, and there is a problem that reliability is low.
[0007]
An object of the present invention is to suppress the deterioration over time of the diameter expansion force of the fixing ring as much as possible.
[0008]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the present invention provides a diameter reduction preventing function between both ends of the split of the fixing ring. With this function, regardless of whether the fixing ring is open or not, the degree of attenuation of the diameter expansion force over time is moderate as compared with the conventional one.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
As an embodiment of the present invention, a fixing ring is provided over the entire inner surface of the cylindrical portion inserted into the inner surface of the tube end of the tube end anticorrosion core, and the anticorrosion core is connected to the cylindrical end by the fixing ring. In the structure in which it is pressed against the inner surface and fixed to the pipe end, the fixing ring is divided in one circumferential direction, and both ends of the fixing ring are overlapped with the inner surface of the pipe end anticorrosion core in a pressure contact state to form a communication hole. A configuration in which a blind rivet is inserted into the communication hole from the inside of the fixing ring and both ends of the fixing ring are fastened by the blind rivet may be employed. In this configuration, both ends of the fixing ring are integrated by rivet fastening, and the function of preventing the diameter expansion of the fixing ring is achieved.
[0010]
As another embodiment, in the above-mentioned embodiment, it is possible to pass a coupling piece between both ends of the fixing ring without overlapping both ends and fasten the both ends via the coupling piece. That is, a fixing ring is provided over the entire inner surface of the cylindrical portion inserted into the inner surface of the tube end portion of the tube end anticorrosion core, and the anticorrosion core is pressed against the inner surface of the tube end portion by the fixing ring. In the structure fixed to the end, the fixing ring is divided by one in the circumferential direction, and at both ends, the fixing ring is overlapped with the inner surface of the pipe end anticorrosion core in a pressure contact state, and the connecting piece and the fixing ring are overlapped. Communication holes are formed between both ends, and blind rivets are respectively inserted into the communication holes from the inside of the fixing ring, and both ends of the fixing ring are fastened to each other through the coupling pieces by the blind rivets. It can be.
[0011]
In the embodiment in which both ends of the fixing ring are overlapped, a plurality of communication holes of the same size are formed at both ends of the fixing ring at equal pitches in the length direction of the fixing ring. The pitch of the communication holes of the portions is different, and the blind rivet may be inserted into the corresponding communication holes at both ends of the fixing ring and the both ends thereof may be fastened.
[0012]
Further, in the embodiment using the coupling piece, a plurality of communication holes of the same size are formed at one end of the fixing ring and the coupling piece at equal pitches in the longitudinal direction, The pitch of the communication hole of the part and the communication hole of the coupling piece are different, and the blind rivet is inserted into the corresponding communication hole of one end part and the coupling piece, and the end part and the coupling piece are fastened Can do.
[0013]
When the pitch of these communication holes is different, both ends or one end and the connecting piece are based on the same function as the caliper main and vernier functions, and due to manufacturing tolerances of the inner diameter of the pipe insertion port, etc. Even if the gap of the one split portion changes, any one of the communication holes can correspond to rivet fastening. That is, it is possible to sufficiently absorb the tolerance of the inner diameter of the tube and perform a strong fastening. At this time, the pitch of the communication holes is appropriately set according to the degree of adjustment with respect to the change of the split portion.
[0014]
Here, the “same size” includes an error that does not impair absorption such as tolerance based on the functions of the main scale and the vernier, and the “corresponding” of the communication hole means that the communication hole has the same axis. It includes not only the case where it is located on the center, but also those that are about the core misalignment that can be fastened by inserting the rivet into both the communication holes without moving both ends of the fixing ring in pressure contact with the anticorrosion core and the connecting piece. Furthermore, the number of both communication holes on the main scale side and the vernier side may be the same, but if the number of communication holes with a large pitch on the main scale side is increased, the length of each communication hole formed, The adjustment width can be widened (see the chain line diagram in FIG. 9A).
[0015]
In the embodiment in which a plurality of both communication holes having the same pitch are formed, both ends of the fixing ring, or one end of the fixing ring and the number of both communication holes of the coupling piece are the same, and the number of communication holes having a large pitch is used. If the value obtained by multiplying the number minus one by the pitch and the value by multiplying the number of communication holes with a small pitch by the pitch are the same, the one at one end of both communication holes will correspond. If there is a deviation of the length obtained by multiplying the pitch difference by the number of one communication hole, the one at the one end of the communication hole with the small pitch is next to the one at the one end with the large pitch. In this state, the displacement is adjusted by the same action (see the embodiment in FIG. 9B).
[0016]
In the embodiment using the coupling piece, a plurality of the communication holes for fastening the other end of the fixing ring and one of the coupling pieces are formed in the length direction of the fixing ring or the coupling piece. The pitch of the communicating holes was multiplied by the pitch difference between the communicating holes of the one end and the connecting piece and the smaller number of communicating holes in the length direction (including the number in the case of the same number). A length configuration may be employed.
[0017]
In this way, by selecting each communication hole of the other end or the coupling piece and changing the fastening position of the other end and the coupling piece, the corresponding communication hole of the one end and the coupling piece can be changed. The reference point changes, and the range of response to changes in the inner diameter of the pipe, such as manufacturing tolerances, is expanded (see the examples in FIGS. 8A to 8C). Here, the length obtained by multiplying the pitch difference by the smaller number of communication holes is determined by the number of corresponding communication holes based on the misalignment between the one end and the coupling piece. The corresponding number depends on the smaller number, for example, 3 and 5 are determined by the former three, and after the third communication hole corresponds, the reference point is shifted, This is to obtain the same function.
[0018]
In each of the above embodiments, it is preferable that a concave portion for accommodating the protrusion from the fixing ring of the blind rivet is formed in the pipe end anticorrosion core so that the anticorrosion core is not pressed by the protrusion of the blind rivet. .
[0019]
Moreover, it is good also as screwing fastening instead of blind rivet fastening. At this time, the communication hole at the end of the fixing ring on the side of the anticorrosion core may be a screw hole, but may be fastened with a tap screw instead of a screw hole.
[0020]
【Example】
An embodiment is shown in FIGS. 1 to 8, and this embodiment is a structure in which an anticorrosion core 7 is attached to the end of the NS-shaped incised slot 2a shown in FIGS. The two end portions 8a and 8b of FIG. The material of the fixing ring 8 and the coupling piece 10 is preferably a spring stainless material, but is not particularly limited to a material having no spring property. In addition, a shape memory alloy and a superelastic alloy can also be used for the fixing ring 8, and these alloys are beneficial from the viewpoint of workability when the diameter of the tube 2 is small. That is, when an anticorrosion core is attached to a pipe having a small diameter, it may be difficult to reduce the diameter with a fixing ring such as a stainless steel material, and workability may be deteriorated. In addition, if the diameter is forcibly reduced, plastic deformation or fracture may be considered. On the other hand, shape memory alloys are generally easily deformable, and at a certain temperature, a shape memory alloy fixing ring memorized so as to expand to an optimum size for fixing the anticorrosion core can enter the inner surface of the anticorrosion core. After being reduced in size and attached to the inner surface of the core, it can be constructed more smoothly by heating to the certain temperature, returning it to its original shape, and fixing the core. Also, the superelastic effect means that even if it is greatly deformed at a temperature higher than the shape recovery temperature, it means that it returns to its original shape again if the stress is removed.If it is a superelastic alloy fixing ring with this characteristic, If it is attached to the inner surface of the core at a temperature higher than the shape recovery temperature, its deformation is easy, plastic deformation does not occur, the shape recovers at room temperature, and the core can be fixed and can be installed smoothly.
[0021]
Five holes 11 are formed at one end of the fixing ring 8 with a 9 mm pitch A ′ in the length direction (A = 36 mm), and three holes are formed at the other end with a 5 mm pitch C ′ in the length direction. 12 is formed (C = 10 mm, see FIG. 7). An insertion hole (jig hole) 13 for the spring pliers P is formed inside both the holes 11 and 12, and the pliers P are inserted into the holes 13 and fixed by the pliers P as shown in FIG. The ring 8 is enlarged or reduced. The connecting piece 10 is formed with five holes 14 having the same size as the holes 11 at a pitch B ′ of 10 mm in the length direction (B = 40 mm) and separated to one side and having the same size as the holes 12. A fixing hole 15 is formed. As shown in FIG. 20, there is no tolerance between the inner surface of the tube and the groove 9 and the fixing ring 8 is simply fitted to the anticorrosion core 7 only by its elasticity, as shown in FIG. When the fixing hole 15 has the same axis as the center of the three holes 12, the left end hole 11 of the one end 8a and the left end hole 14 of the coupling piece 10 are set to have the same axis ( FIG. 7). Further, the fixing hole 15 can have the same axial center as that of the left end of the three holes 12 (see FIG. 8). In this case, when the fixing ring 8 is fitted in the groove 9, there is no diameter reduction. The diameter must be expanded. The gap between both end portions 8a and 8b of the fixing ring 8 when these referenced gap Y _0. The reference gap Y ₀ may be in a good pressure contact state of the anticorrosion core 7 in which the fixing ring 8 is expanded in diameter by the spring pliers P when there is no tolerance.
[0022]
If the connecting piece 10 and the one end 8a of the fixing ring 8 are a caliper main scale and a sub-scale, a hole 11 having the same axial center according to the degree of displacement between the holes 11 and 14 due to the pitch difference between the holes 11 and 14 14 will change. That is, in FIG. 8 (a), in the state where the center of the hole 15 and the left end hole 12 are aligned (with the same axis), one end 8a moves in the direction of the arrow as shown in FIG. 8 (b). When the diameter of the ring 8 is increased (when the gap between the end portions 8a and 8b becomes Y), for example, when the ring 8 moves, the centers of the fourth holes 11 and 14 from the left side coincide. Thus, the matching holes 11 and 14 change by 1 mm. For this reason, if the rivet 20 is inserted and fastened in the matched holes 11 and 14, the diameter-expanded state is reliably maintained.
[0023]
In the case of a displacement of 4 mm or more, as shown in FIG. 8 (c), when the hole 15 is aligned with the hole 12 on the right side, the displacement is 5mm. The holes 14 coincide. If there is a displacement of 9 mm or more, when the hole 15 is made to coincide with the hole 12 at the right end, any one of the holes 11 and the hole 14 coincide with each other up to a displacement of 14 mm. For this reason, in this embodiment, it is possible to cope from the reference gap Y ₀ to the 14 mm expansion gap of the gap Y.
[0024]
From this idea, by arbitrarily setting the pitches A ′ and B ′ of the holes 11 and 14 and the number thereof and the number of the holes 12 (see FIG. 7), the diameter deviation from the reference gap Y ₀ is arbitrarily taken. You can get. Further, if the reference gap Y ₀ is set when the hole 15 corresponds to the intermediate hole 12 instead of the holes 12 at both ends, it can correspond to both the fixed state in which the diameter is reduced or expanded from the reference gap Y _0. . One hole 12 and a plurality of holes 15 may be provided.
[0025]
The blind rivet 20 shown in FIG. 6 that can be fastened only from one side is adopted as the rivet, and this blind rivet 20 comprises a cylindrical rivet main body 21 and a pulling rod 22 inserted through the main body 21. As shown in (a), by inserting the holes 11 and 12 of the fixing ring ends 8a and 8b and the holes 14 and 15 of the coupling piece 10 and pulling the pulling rod 22 as shown in FIG. The ear portion 21a of the main body 21 is bulged with the portion 22a, and the fixing ring 8 and the coupling piece 10 are sandwiched between the bulged portion 21a and the upper flange 21b to fasten them together. At this time, since the bulging portion 21 a protrudes from the surface of the fixing ring 8, the portion corresponding to the holes 11 and 12 of the anticorrosion core 7 forms a groove 16, and the bulging portion 21 a (head 22 a) is formed by the groove 16. It should be stored. Thereby, the fixing ring 8 does not float from the anticorrosion core 7, and the anticorrosion core 7 is not damaged. However, the groove 16 can be omitted if there is no problem.
[0026]
This embodiment is configured as described above. Next, the mounting operation of this embodiment will be described. First, the fixing ring 8 is fitted into the groove 9 of the anticorrosion core 7, and the snap ring pliers P are inserted into the jig hole 13. Expand the diameter. The diameter is increased to such an extent that the fixing ring 8 provides an appropriate pressure-bonding force to the anticorrosion core 7 to effectively prevent the peeling, and the rivet 20 is inserted into the corresponding holes 11 and 14 and tightened by the increased diameter. To do. At this time, as shown in FIG. 5, the corresponding holes 11 and 14 may be confirmed by the gauge 25. That is, the gauge 25 cannot be inserted into the holes 11 and 14 if they do not correspond to each other as shown in FIG. It can be inserted and the correspondence can be confirmed. Further, as shown in FIGS. 7 and 8, numerical values such as 0 to 4 are sequentially assigned to the holes 11 and 14 in the row direction, the gap Y after the diameter expansion is measured, and the gap Y and the reference gap Y are measured. _If the difference is ₀ , and the difference holes 11 and 14 are, for example, 3 mm, the rivet 20 can be inserted into the holes 11 and 14 having the numerical value 3. In place of the spring pliers P, other tools such as a pin spanner and a giant clam vise may be employed.
[0027]
As shown in FIG. 9, the number of the holes 12 in the other end portion 8b of the fixing ring 8 may be one, and the number of the holes 11 and 14 is arbitrary as described above, such as 10 in the figure. Further, the number of the communication holes 11 and 14 on the main scale side and the vernier side is the same number, and a numerical value obtained by multiplying the number obtained by subtracting one from the number of communication holes 14 having a large pitch, and a small pitch. If the number obtained by multiplying the number of the communication holes 11 by the pitch is set to be the same, for example, in the embodiment of FIG. 9A, the pitch difference of one communication hole is added to the pitch difference as shown in FIG. If a deviation of the length multiplied by the number occurs, the end of the communication hole 11 with a small pitch corresponds to the next of the one end with the large pitch (the reference point becomes the next hole 14). ) From this state, the deviation is adjusted by the same action. Further, as shown in FIG. 10, the one end 8a side of the fixing ring 8 can be the main scale side, and the coupling piece 10 can be the vernier side (B ′ <A ′, B <A).
[0028]
In the fastening by the above-mentioned coupling piece 10, the rivet fastening between the coupling piece 10 and the other end portion 8b of the fixing ring 8 is performed before the fixing ring 8 is fitted into the groove 9, before the expansion / contraction diameter after the fitting, and the same expansion / contraction. Any of the following may be used, but when there are a plurality of holes 12 and 15, the width of the expansion shift can be set arbitrarily by selecting the holes, and therefore it is preferable to be after the expansion / contraction diameter.
[0029]
11 and 12 show an embodiment in which both end portions 8a and 8b of the fixing ring 8 are overlapped without using the coupling piece 10, and the modes of the holes 11, 13, and 14 are the same as those described above. In each of the above embodiments including this embodiment, the number of communication holes on the main scale side can be made larger than the number of communication holes on the vernier side (see the chain line diagram in FIG. 9A). By doing so, the diameter expansion deviation can be adjusted within the range of the number of communication holes on the main scale side so that the caliper can be measured within the range of the main scale. At this time, if the jig hole 13 gets in the way, it is displaced appropriately.
[0030]
FIGS. 13A and 14A show the case where fine adjustment is not necessary in each of the above-described embodiments, that is, the case where the diameter change of the fixing ring 8 can be absorbed only by the compressibility of the anticorrosion core 7. At this time, the number of holes 11 and 14 is one. At this time, one of the holes 11 and 14 may be formed on the construction site corresponding to the other. On the other hand, as shown in FIG. 2B, either one of the holes 11 or 14 is formed in the length direction so that the diameter change of the fixing ring 8 can be absorbed by the selection of the holes. obtain. At this time, the pitches of the holes 11 and 14 are preferably equal, but may be appropriate.
[0031]
15 to 18 show various aspects of the pipe end portion to which the anticorrosion core 7 is fixed, FIG. 15 shows the fixing ring 8 positioned by the annular step portion 9a, and FIG. 16 shows wear of the anticorrosion core 7. The wear-resistant layer 7a is formed by fusion of an ultra-high molecular weight polyethylene film at an easy place. FIG. 17 shows the peeling of the core 7 by interposing the upper edge portion of the anticorrosion core 7 on the lower surface of the insertion ring 4. FIG. 18 is a diagram in which a rib 8 c is provided on the fixing ring 8 over the entire length in the length direction so that the fixing state of the fixing ring 8 is strengthened. Each of these examples may adopt their features mutually.
[0032]
In each of the above embodiments, the members 8a, 8b, and 10 are fastened by the blind rivet 20. However, in the embodiment of FIG. 1, the holes 11 on both ends 8a and 8b of the fixing ring 8 are provided. Can be fastened by screwing a screw through the hole 14 into the screw hole. If it is a tapping screw, it is not necessary to make the hole 11 etc. into a screw hole.
[0033]
The embodiment was NS type, but the present invention can be applied not only to the fixing structure of the anticorrosion core at the pipe end of other types, but also to the pipe end of the standard specification, not limited to the cut pipe. Of course.
[0034]
【The invention's effect】
As described above, since the present invention provides the fixing ring with the function of preventing the diameter reduction, the aging degradation of the diameter expansion force of the fixing ring is also suppressed, and therefore, the sufficient adhesion to the tube end of the waterproof core has also been maintained for many years. The anticorrosion core is effectively prevented from falling off against expansion / contraction / bending of the joint portion, and red water can be prevented over a long period of time.
[Brief description of the drawings]
FIG. 1 is a perspective view of the main part of one embodiment. FIG. 2 is a plan view of the main part of FIG. 1. FIG. 3 is a cutaway view of the main part of FIG. 5] Action diagram of fastening ring of the same embodiment [FIG. 6] Action diagram of the blind rivet of the same embodiment [FIG. 7] Action diagram of the same embodiment [FIG. 8a] Action diagram of the same embodiment [FIG. FIG. 8c is an operational diagram of the embodiment. FIG. 9 is an operational diagram of the other embodiment. FIG. 10 is an operational diagram of the other embodiment. 12A is a perspective view of a fixing ring of the same embodiment, FIG. 12B is an operation view of the same embodiment, FIG. 13 is a perspective view of a fixing ring of each of the other embodiments, and FIG. FIG. 15 is a cross-sectional view of another example of the pipe end anticorrosion structure. FIG. 16 is a cross-sectional view of another example of the pipe end anticorrosion structure. FIG. 18: Pipe end Enlarged sectional view of another example of a cross-section view fragmentary cross-sectional view of FIG. 19 pipe joint [20] tube inserted port food structure EXPLANATION OF REFERENCE NUMERALS
1, 2 Tube 1a Receptacle 2a Insert 7 Corrosion-proof core 8 Corrosion-proof core fixing ring 8a, 8b Fixing ring end 9 Fixing ring fitting groove 10 Coupling pieces 11, 12, 13, 14, 15 Hole 16 Rivet groove ( Recess)
20 Blind rivet P Snap ring pliers (expansion jig)

Claims (8)

A fixing ring 8 is provided over the entire inner circumference of the cylindrical portion inserted into the inner surface of the tube end portion of the tube end anticorrosion core 7, and the cylindrical end portion of the tube end anticorrosion core 7 is formed on the inner surface of the tube end portion by the fixing ring 8. It is a structure that is fixed to the pipe end by pressure welding,
The fixing ring 8 is divided in one circumferential direction, and both end portions 8a and 8b of the fixing ring 8 overlap with the inner surface of the pipe end anticorrosive core 7 in a press-contact state to form communication holes 11 and 14, respectively. 14, a blind rivet 20 is inserted from the inside of the fixing ring 8, and both ends 8a and 8b of the fixing ring 8 are fastened by the blind rivet 20. A fixing ring 8 is provided over the entire inner circumference of the cylindrical portion inserted into the inner surface of the tube end portion of the tube end anticorrosion core 7, and the cylindrical end portion of the tube end anticorrosion core 7 is formed on the inner surface of the tube end portion by the fixing ring 8. It is a structure that is fixed to the pipe end by pressure welding,
The fixing ring 8 is divided by one in the circumferential direction, and at both ends 8a and 8b, the fixing ring 8 is overlapped with the inner surface of the pipe end anticorrosive core 7 in a pressure contact state, and the connecting piece 10 and the fixing ring are overlapped. 8, communication holes 11, 12, 14, and 15 are formed between both ends, respectively, and blind rivets 20 are inserted into the communication holes 11, 14, 12, and 15 from the inside of the fixing ring 8, respectively. The fixing structure of the pipe end anticorrosion core, wherein both ends of the fixing ring 8 are fastened by the joint piece 10 by 20. In claim 1, a plurality of communication holes 11, 14 having the same size are formed at both ends 8 a, 8 b of the fixing ring 8 at equal pitches in the length direction of the fixing ring 8, and both ends 8 a, The pitch of the communication holes 11 and 14 of 8b is different, and the blind rivet 20 is inserted into the corresponding communication holes 11 and 14 of the both ends 8a and 8b of the fixing ring 8 and the both ends 8a and 8b are fastened. A structure for fixing a pipe end anticorrosion core, characterized by comprising: In Claim 2, the one end 8a of the fixing ring 8 and the coupling piece 10 are each formed with a plurality of communication holes 11, 14 of the same size at equal pitches in the length direction, and the end thereof. The pitch of the communication hole 11 of 8a and the communication hole 14 of the coupling piece 10 are different, and the blind rivet 20 is inserted into the corresponding communication holes 11 and 14 of the coupling piece 10 and the end 8a. The fixing structure of the pipe end anticorrosion core, wherein the coupling piece 10 is fastened. In Claim 4, the other end portion 8b of the fixing ring 8 and one of the coupling pieces 10 have the communication holes 12 and 15 for fastening the both 8b and 10 in the length of the fixing ring 8 or the coupling piece 10. A plurality of communication holes 12 and 15 are formed in the direction, and the pitch of the communication holes 12 and 15 is less than the pitch difference between the one end 8a and the communication holes 11 and 14 of the coupling piece 10 and the communication holes 11 and 14 in the length direction. A structure for fixing a pipe end anticorrosion core characterized by having a length multiplied by the number of sides. In Claim 3 or 4, the number of both ends 8a and 8b of the fixing ring 8, or one end portion 8a of the fixing ring 8 and both the communication holes 11 and 14 of the coupling piece 10 is the same, and the number of communication holes having a large pitch is obtained. A pipe end anticorrosive core fixing structure, wherein a numerical value obtained by multiplying the number minus one by the pitch and a numerical value obtained by multiplying the number of communication holes having a small pitch by the pitch are the same. The pipe end anticorrosive core according to any one of claims 1 to 6, wherein the pipe end anticorrosive core 7 is formed with a recess 16 for accommodating a protrusion from the fixing ring 8 of the blind rivet 20. Construction. The pipe end anticorrosion core fixing structure according to any one of claims 1 to 7, wherein a fastening by screws is used in place of the fastening by the blind rivet 20.

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