JP2023152292A - Joint and pipe structure - Google Patents

Abstract

To provide a joint that adjusts a direction of a pipe conduit, and into which a cable or the like is easily inserted, and a pipe structure.SOLUTION: A joint 30 is a tubular joint 30 that extends along a linear pipe axis X. The joint 30 has a first socket 31 into which a first protection pipe 10 is fitted at one end 31a, a first spigot 32 into which a second protection pipe 20 is fitted at the other end 32a, and an intermediate part 33 between the first socket 31 and the first spigot 32. The first socket 31 has a socket enlarged diameter part 35 that increases in diameter from one end 31a toward the other end 32a. The first spigot 32 has a uniform annular cross section along a pipe axis X. A minimum inner diameter of the first socket 31 is larger than an outer diameter of the first spigot 32. A minimum inner diameter of the intermediate part 33 is smaller than the outer diameter of the first spigot 32.SELECTED DRAWING: Figure 5

Description

The present invention relates to a joint and piping structure.

BACKGROUND ART Conventionally, in a piping structure of a protection tube that protects a cable, there has been a piping structure in which protection tubes are connected to each other by a joint so that the direction of the pipe can be adjusted (see Patent Documents 1 to 3).

JP2017-163627A JP2017-198338A JP2020-014290A

A conventional piping structure in which the direction of the pipes can be freely adjusted is a structure in which protection tubes are connected to each other with a joint. Therefore, in a piping structure where the pipe direction is bent, the step created between the ends of the protection tubes inside the joint may prevent a linear cable with a circular cross section or a cable that is inserted into the piping structure. In some cases, it became difficult to insert a right cylindrical continuity test rod (hereinafter referred to as a cable, etc.) having a simulated outer diameter and length.

The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide a joint and a piping structure in which the direction of the pipe line can be freely adjusted and cables and the like can be easily inserted therethrough.

The means for solving the above problems are as follows.
(1) A joint according to one aspect of the present invention is a tubular joint that extends along a linear tube axis, and has a first socket at one end into which a first protection pipe is fitted, and a second protection pipe. A first spigot into which a pipe is fitted is provided at the other end, an intermediate portion is provided between the first spigot and the first spigot, and the first spigot extends from the one end to the other end. The first socket has a diameter-expanding part that expands toward the pipe axis, and the first socket has a uniform annular cross section along the pipe axis, and the first socket has a minimum inner diameter of The minimum inner diameter of the intermediate portion is larger than the outer diameter of one spigot, and the minimum inner diameter of the intermediate portion is smaller than the outer diameter.
(2) In (1) above, the first length of the first socket along the tube axis is equal to the second length of the first spigot along the tube axis.
(3) In (1) or (2) above, the socket enlarged diameter portion may have an elliptical cross section.
(4) In any one of (1) to (3) above, the socket enlarged diameter portion may have a tapered surface.
(5) In any one of (1) to (4) above, the intermediate portion may have an elliptical cross section.
(6) In any one of (1) to (5) above, the intermediate portion may have an intermediate enlarged diameter portion whose diameter increases as the distance from the one end increases.
(7) A piping structure according to one aspect of the present invention includes the first protection tube and the second protection tube, and includes any of the joints (1) to (6) above.
(8) In the above (7), the first protection tube or the second protection tube may be a straight tube.
(9) In the above (7), the first protection tube or the second protection tube may have the same shape as the joint.

According to the present invention, it is possible to provide a joint and piping structure in which the direction of the pipe line can be freely adjusted and cables and the like can be easily inserted therethrough.

FIG. 2 is a cross-sectional view of the joint according to the first embodiment when viewed from above. FIG. 2 is a sectional view taken along arrow A in FIG. 1. FIG. FIG. 2 is a sectional view taken along arrow B in FIG. 1. FIG. FIG. 2 is a sectional view taken along arrow C in FIG. 1. FIG. 2 is a sectional view taken along arrow D in FIG. 1. FIG. FIG. 2 is a cross-sectional view of the joint according to the first embodiment, viewed from the front. 4 is a sectional view taken along arrow A in FIG. 3. FIG. 4 is a sectional view taken along arrow B in FIG. 3. FIG. 4 is a sectional view taken along arrow C in FIG. 3. FIG. 4 is a sectional view taken along arrow D in FIG. 3. FIG. FIG. 2 is a cross-sectional view of the piping structure according to the first embodiment in a state where the piping direction is bent when viewed from above. It is an explanatory view showing a situation where a continuity test rod is passed through the piping structure according to the first embodiment in a state where the pipe direction is bent. It is an explanatory view showing a situation where a continuity test rod is passed through the piping structure according to the first embodiment in a state where the pipe direction is bent. FIG. 7 is a cross-sectional view of a joint according to a second embodiment when viewed from above. FIG. 7 is a cross-sectional view of a joint according to a third embodiment when viewed from above. FIG. 7 is a cross-sectional view of a joint according to a first modification seen from a plane. FIG. 7 is a cross-sectional view of a joint according to a second modification seen from a plane. FIG. 7 is a cross-sectional view of a joint according to a third modification seen from a plane. It is a sectional view seen from the plane of the joint concerning the 4th modification.

(First embodiment)
The joint 30 and piping structure 1 according to the first embodiment will be described below with reference to the drawings.
FIG. 1 is a sectional view of a joint 30 according to the first embodiment viewed from above. FIG. 2A is a sectional view taken along arrow A in FIG. FIG. 2B is a sectional view taken along arrow B in FIG. 1. FIG. FIG. 2C is a sectional view taken along arrow C in FIG. FIG. 2D is a sectional view taken along arrow D in FIG. FIG. 3 is a sectional view of the joint 30 according to the first embodiment viewed from the front. 4A is a cross-sectional view taken along arrow A in FIG. 3. FIG. FIG. 4B is a sectional view taken along arrow B in FIG. 3. FIG. FIG. 4C is a sectional view taken along arrow C in FIG. 3. FIG. 4D is a sectional view taken along arrow D in FIG. 3. FIG. 5 is a cross-sectional view of the piping structure 1 according to the first embodiment in a state where the pipe direction is bent when viewed from above. Note that FIGS. 1 to 5 show cross sections passing through the tube axis X.

(Piping structure)
As shown in FIG. 5, the piping structure 1 according to the first embodiment includes a first protection tube 10 and a second protection tube 20, and includes a joint 30.
The piping structure 1 may include a plurality of joints 30 connected together. The length of each of the first protection tube 10, the second protection tube 20, or the joint 30 (dimension along the tube axis It is set appropriately according to the outer diameter, curvature, and angle of the cable, etc., which are passed through the cylindrical space (a cylindrical space through which the cable, etc. passes), and the inner diameter, curvature, and angle of the conduit. For example, as shown in FIG. 5, the first protection pipe 10, the joint 30 (one joint 30), and the second protection pipe 20 (the other joint 30) may be connected in this order. Thereby, the piping structure 1 can be obtained in which a pipe line having a desired curvature and a desired angle is formed.

The first protection tube 10 or the second protection tube 20 may be a so-called straight tube whose inner diameter, outer diameter, and wall thickness are uniform along the tube axis. The first protection tube 10 and the second protection tube 20 may have the same size. By connecting the first protection tube 10 and the second protection tube 20 via the joint 30, even if the first protection tube 10 or the second protection tube 20 is a straight pipe, the inside of the piping structure 1 can be It is possible to form a bent conduit through which a bent cable or the like can be inserted and placed.

The first protection tube 10 or the second protection tube 20 may have the same shape as the joint 30. That is, the first protective tube 10 connected to the first socket 31 of the joint 30 may have the same shape as the joint 30. The second protective tube 20 connected to the first spigot 32 of the joint 30 may have the same shape as the joint 30. In other words, the piping structure 1 may include two or more joints 30 connected in succession. Thereby, a piping structure 1 in which a plurality of joints 30 having the same shape are connected can be formed. Depending on the length of the joint 30 and the number of joints 30 to be connected, a conduit curved at a desired angle with a desired curvature can be formed.

For example, as shown in FIG. 5, the first protective tube 10 that fits into the first socket 31 of one joint 30 is a so-called straight tube, and the second protective tube 20 that fits into the first socket 32 of one joint 30 is a straight pipe. It may be used as the other joint 30. That is, as shown in FIG. 5, the piping structure 1 may connect a plurality of joints 30 (one joint 30 and the other joint 30) in succession.

(fitting)
As shown in FIGS. 1 and 3, the joint 30 is tubular and extends along a linear tube axis X. This allows manufacturing costs to be reduced compared to a so-called curved pipe that extends along a curved pipe axis.

The joint 30 has a first socket 31 at one end 31a into which the first protection tube 10 is fitted, a first socket 32 into which the second protection tube 20 is fitted at the other end 32a, and a first socket 31 into which the first protection tube 10 is fitted. An intermediate portion 33 is provided between the opening 31 and the first spigot 32 .

The first spigot 32 has a uniform annular cross section along the tube axis X. It is preferable that the outer diameter φ2 of the first spigot 32 is the same as the outer diameter of the first protective tube 10. Thereby, the first protective tube 10 that fits into the first socket 31 of the joint 30 can be either a straight pipe or the first spigot 32 of the other joint 30.

Here, the first socket 31 has a socket enlarged diameter portion 35 that increases in diameter from one end 31a toward the other end 32a. Thereby, the first spigot 32 inserted into the first socket 31 can be supported rotatably within the range of the predetermined bending angle θ.

The minimum inner diameter D1 of the first socket 31 is larger than the outer diameter φ2 of the first spigot 32. The minimum inner diameter D4 of the intermediate portion 33 is smaller than the outer diameter φ2. In this way, the minimum inner diameter D1 of the first socket 31 is larger than the outer diameter φ2 of the first socket 32, so the first socket 31 of one joint 30 is connected to the first socket 32 of the other joint 30. It can be fitted. Therefore, a plurality of joints 30 having the same shape can be connected in succession. Furthermore, since the minimum inner diameter D4 of the intermediate portion 33 is smaller than the outer diameter φ2, the outer diameter φ2 portion of the first socket 32 of the other joint 30 that is fitted into the first socket 31 of one joint 30 is , interferes with the minimum inner diameter D4 of the intermediate portion 33 of one joint 30. Therefore, the first socket 32 of the other joint 30, which is inserted into the first socket 31 of one joint 30, is not moved further back (towards the first socket 32 of one joint 30). Can be done. Since the first socket 31 has a socket enlarged diameter part 35 that expands in diameter from one end 31a to the other end 32a, the other joint 30 inserted therein is inserted inside the socket enlarged diameter part 35. The first spigot 32 (or the first protection tube 10) can be freely swung within a predetermined bending angle θ. By bending the pipe axes X of the continuously connected joints 30 at a desired bending angle θ and adjusting the pipe direction (direction along the pipe axis Can be formed. As shown in FIG. 5, even when the pipe direction is bent, a part of the end 10E of the first protective tube 10 inserted into the first socket 31 is inserted into the socket enlarged diameter part 35. This allows the pipe to be accommodated in a space whose diameter has been enlarged, and it is possible to prevent the formation of a step in the conduit that would impede the insertion of a cable or the like. Therefore, it is possible to provide the joint 30 and piping structure 1 in which the direction of the pipe line can be freely adjusted and cables and the like can be easily inserted.

It is preferable that the first length L1 of the first socket 31 along the tube axis X is equal to the second length L2 of the first difference port 32 along the tube axis X. As a result, as shown in FIG. 5, while the first socket 32 of one joint 30 is inserted into the first socket 31 of the other joint 30, While the first spigot 32 of the other joint 30 is inserted, the end 30E of the first spigot 32 of the other joint 30 can be placed inside the enlarged socket portion 35 of one of the joints 30.

The socket enlarged diameter portion 35 may have a tapered surface 35T. Thereby, the side surface of the first protection tube 10 inserted into the first socket 31 can be received by the surface. Therefore, the bending angle θ of the conduit can be reliably regulated.

The enlarged socket portion 35 may have an elliptical cross section. As a result, as shown in FIG. 2C, the cross section of the socket enlarged diameter portion 35 has a short axis length D5 smaller than the outer diameter φ2 of the first protective tube 10 (or the first spigot 32 of the other joint 30). and a major axis length D2 larger than the outer diameter φ2 of the first protective tube 10 (or the first spigot 32 of the other joint 30). Therefore, when the first protective tube 10 (or the first spigot 32 of the other joint 30) having a circular outer peripheral surface with an outer diameter φ2 is inserted into the first socket 31 of the joint 30, the overlapping length is When increasing, the end 10E of the first protection tube 10 (or the end 30E of the other joint 30) interferes with the short axis of the socket enlarged diameter part 35 (see section F in FIG. 5). . Therefore, the first protective tube 10 inserted into the first socket 31 of one joint 30 (or the first socket 32 of the other joint 30) can be inserted deeper (the first socket 32 of one joint 30) into the first socket 31 of one joint 30. It can be prevented from moving to the mouth 32 side).

(Seal ring)
The joint 30 is a seal ring disposed between the inner peripheral surface of the first socket 31 of the joint 30 and the outer peripheral surface of the first protective tube 10 (or the outer peripheral surface of the first spigot 32 of the other joint 30). 34. The seal ring 34 provides an airtight or watertight seal between the joint 30 and the first protection tube 10 (or the other joint 30). The inner diameter of the seal ring 34 is compressed and deformed in the diametrical direction when the first protective tube 10 (or the first spigot 32 of the other joint 30) is inserted into the first socket 31, and the inner diameter expands. The minimum inner diameter of one socket 31 is D1. The seal ring 34 may be a rubber ring, for example. Thereby, as shown in FIG. 5, the joint 30 can rotatably support the first protection tube 10 (or the other joint 30) by the seal ring 34 within the range of the bending angle θ. At this time, the intersection Y can be located inside the seal ring 34. Therefore, the piping structure 1 can be bent at the bending angle θ centering on the intersection Y of the adjacent pipe axes X.

The intermediate portion 33 may have an elliptical cross section. As a result, as shown in FIG. 2B, the cross section of the intermediate portion 33 is changed to the minimum inner diameter that has a short axis length smaller than the outer diameter φ2 of the first protection tube 10 (or the first difference port 32 of the other joint 30). D4, and a maximum outer diameter D3 having a major axis length larger than the outer diameter φ2 of the first protective tube 10 (or the first spigot 32 of the other joint 30). Therefore, when the first socket 31 of one joint 30 is inserted into the first socket 32 of the other joint 30, which has a circular cross section with an outer diameter φ2, and the overlapping length is increased, The end of the first socket 31 of one joint 30 interferes with the outer peripheral surface of the long axis portion of the intermediate portion 33 of the other joint 30 (see section K in FIG. 5). Therefore, the first socket 32 of the other joint 30, which is inserted into the first socket 31 of one joint 30, is not moved further back (towards the first socket 32 of one joint 30). Can be done.

For example, if the first protective tube 10 has a nominal diameter of 100 (outer diameter 114 mm, inner diameter 100 mm) and the total length (effective length) of the first socket 31 and the intermediate part 33 is 500 mm, the first socket of the joint 30 By setting the bending angle θ at the mouth 31 to 5.75°, a piping structure 1 with a curvature of 5 mR using two joints 30 as shown in FIG. 5 can be obtained. In this case, the inner diameter of the intermediate portion 33 is 124 mm or more, and the length of the first spigot 32 is 142 mm.
In addition, when three joints 30 are used, the bending angle θ is set to 3.82°, so that the piping structure 1 can have a curvature of 5 mR. In this case, the lengths of the first socket 31 and the intermediate portion 33 and the length of the first spigot 32 are adjusted as appropriate. The bending angle θ can be made small by using a plurality of joints 30, but the use of a large number of joints 30 increases the cost and construction of the piping structure 1, so the bending angle θ should be 2.86° or more. It is preferable that the shape is such that it can be bent within a range of 5.75° or less.

(effect)
The operation of the piping structure 1 will be explained using FIGS. 5 to 7.
FIG. 5 is a cross-sectional view of the piping structure 1 according to the first embodiment in a state where the pipe direction is bent when viewed from above. FIG. 6 is an explanatory diagram showing a situation where the continuity test rod CM is passed through the piping structure 1 according to the first embodiment in a state where the pipe direction is bent. FIG. 7 is an explanatory diagram showing a situation where the continuity test rod CM is passed through the piping structure 1 according to the first embodiment in a state where the pipe direction is bent. Note that FIGS. 5 to 7 show cross sections passing through the tube axis X.

The pipe line of the piping structure 1 assembled by connecting the first protection pipe 10, one joint 30, and the other joint 30 (second protection pipe 20) is connected to the tube axis X1 of the first protection pipe 10, and the other joint 30 (second protection pipe 20). As shown in FIG. In order to form a conduit for passing a bent cable or the like, the tube axis X1 and the tube axis X2 are made to intersect with the tube axis X3, so that the direction of the conduit is bent at a bending angle θ. Then, the end portion 10E of the first protective tube 10 comes into contact with the inner surface of the socket enlarged diameter portion 35 of the first socket 31 of the joint 30, and further rotation is suppressed. On the other hand, the end 30E of the first spigot 32 of the joint 30 comes into contact with the inner surface of the enlarged diameter part 35 of the first socket 31 of the other joint 30, and further rotation is suppressed. In this way, the first protection tube 10 or the second protection tube connected to the joint 30 can be made rotatable according to a desired curvature, and the maximum bending angle θ can be defined.
In addition, as shown in FIGS. 5 to 7, the end 10E of one joint 30 and the end 30E of the other joint 30 are formed in an enlarged diameter socket formed in each of the one joint 30 and the other joint 30. It is located in section 35. As shown in FIGS. 6 and 7, for example, the inner diameter of the first protective tube 10 (the dimension obtained by subtracting twice the wall thickness from the outer diameter φ2), which simulates a power cable inserted into the piping structure 1, is It is possible to smoothly pass a right cylindrical continuity test rod CM having a 10 mm smaller outer diameter and a length of 400 mm from the first protection tube 10 through the joint 30 to the second protection tube 20 (the other joint 30). can. In this way, cables and the like can be easily inserted into the pipe line formed by the piping structure 1.

(Second embodiment)
Next, a joint 30 and piping structure 1 according to a second embodiment will be described with reference to the drawings. Note that in the description of the second embodiment, characteristic parts having functions common to those of the first embodiment may be given the same reference numerals. Note that in the description of the second embodiment, descriptions of characteristic parts having functions common to those of the first embodiment may be omitted.
FIG. 8 is a cross-sectional view of the joint 30 according to the second embodiment when viewed from above. Note that FIG. 8 shows a cross section passing through the tube axis X.

As shown in FIG. 8, the piping structure 1 according to the second embodiment, like the piping structure 1 according to the first embodiment, includes a first protection tube 10 (not shown in FIG. 8) and a second protection tube 20. (not shown in FIG. 8).

Here, the intermediate portion 33 of the joint 30 according to the second embodiment has an intermediate enlarged diameter portion 36 whose diameter increases as the distance from the other end 32a increases. Note that the intermediate portion 33 may have a uniform annular cross section along the tube axis X. The intermediate enlarged diameter portion 36 may have a uniform annular cross section along the tube axis X. That is, the intermediate portion 33 and the intermediate enlarged diameter portion 36 do not need to be elliptical. As a result, when fitting the first socket 31 of the other joint 30 into the first socket 32 of one joint 30, the end of the first socket 31 of the other joint 30 is attached to the first socket 32 of one joint 30. interferes with the outer circumferential surface of the intermediate enlarged diameter portion 36. Therefore, the overlapping length of one joint 30 and the other joint 30 can be regulated. Moreover, it can be easily manufactured by blow molding or the like.

(Third embodiment)
Next, a joint 30 and piping structure 1 according to a third embodiment will be described with reference to the drawings. Note that in the description of the third embodiment, the same reference numerals may be attached to characteristic parts having functions in common with those of the first embodiment or the second embodiment. Note that in the description of the third embodiment, descriptions of characteristic parts having functions common to those of the first embodiment or the second embodiment may be omitted.
FIG. 9 is a cross-sectional view of the joint 30 according to the third embodiment when viewed from above. Note that FIG. 9 shows a cross section passing through the tube axis X.

As shown in FIG. 9, the piping structure 1 according to the third embodiment is similar to the piping structure 1 according to the first embodiment and the piping structure 1 according to the second embodiment. (not shown) and a second protection tube 20 (not shown in FIG. 9).

Here, the intermediate portion 33 of the joint 30 according to the third embodiment has an intermediate enlarged diameter portion 36 whose diameter increases as the distance from the other end 32a increases, similarly to the piping structure 1 according to the second embodiment. Here, the intermediate expanded diameter portion 36 according to the third embodiment is provided approximately at the center of the intermediate portion 33 in the tube axis X direction. Note that the intermediate portion 33 may have a uniform annular cross section along the tube axis X. The intermediate enlarged diameter portion 36 may have a uniform annular cross section along the tube axis X. That is, the intermediate portion 33 and the intermediate enlarged diameter portion 36 do not need to be elliptical. As a result, when fitting the first socket 31 of the other joint 30 into the first socket 32 of one joint 30, the end of the first socket 31 of the other joint 30 is attached to the first socket 32 of one joint 30. interferes with the outer circumferential surface of the intermediate enlarged diameter portion 36. Therefore, the overlapping length of one joint 30 and the other joint 30 can be regulated. Moreover, it can be easily manufactured by blow molding or the like.

As explained above, the joint 30 according to the second and third embodiments is a tubular joint 30 that extends along the linear tube axis X. The joint 30 has a first socket 31 at one end 31a into which the first protection tube 10 is fitted, a first socket 32 into which the second protection tube 20 is fitted at the other end 32a, and a first socket 31 into which the first protection tube 10 is fitted. An intermediate portion 33 is provided between the opening 31 and the first spigot 32 . The first socket 31 has a socket enlarged diameter portion 35 that increases in diameter from one end 31a toward the other end 32a. The first spigot 32 has a uniform annular cross section along the tube axis X. The minimum inner diameter D1 of the first socket 31 is larger than the outer diameter φ2 of the first spigot 32. The minimum inner diameter D4 of the intermediate portion 33 is smaller than the outer diameter φ2. In this way, the minimum inner diameter D1 of the first socket 31 is larger than the outer diameter φ2 of the first socket 32, so the first socket 31 of one joint 30 is connected to the first socket 32 of the other joint 30. It can be fitted. Therefore, a plurality of joints 30 having the same shape can be connected in succession. Furthermore, since the minimum inner diameter D4 of the intermediate portion 33 is smaller than the outer diameter φ2, the outer diameter φ2 portion of the first socket 32 of the other joint 30 that is fitted into the first socket 31 of one joint 30 is , interferes with the minimum inner diameter D4 of the intermediate portion 33 of one joint 30. Therefore, the first spigot 32 (or straight pipe) of the other joint 30, which is inserted into the first socket 31 of one joint 30, can be prevented from moving further back. A portion of the intermediate portion 33 having the minimum inner diameter D4 functions as a stopper in the first socket 31. However, the minimum inner diameter D4 is larger than the outer diameter of the continuity test rod CM (the minimum inner diameter D4 is 10 mm larger than the inner diameter of the first protective tube 10 (the dimension obtained by subtracting twice the wall thickness from the outer diameter φ2). ). Therefore, the continuity test rod CM can pass through the portion having the minimum inner diameter D4. Furthermore, the intermediate portion 33 is provided with an intermediate enlarged diameter portion 36 . Therefore, when the continuity test rod CM is located in the intermediate portion 33, the continuity test rod CM can be tilted with respect to the tube axis X by utilizing the space expanded by the intermediate enlarged diameter portion 36. can. As a result, even if the piping structure including the joint 30 having the stopper is bent in the direction of the pipe, the continuity test rod CM can pass through the pipe. Since the first socket 31 has a socket enlarged diameter part 35 that expands in diameter from one end 31a to the other end 32a, the other joint 30 inserted therein is inserted inside the socket enlarged diameter part 35. The first spigot 32 (or the first protection tube 10) can be freely swung within a predetermined bending angle θ. By adjusting the direction of the pipe by bending the pipe axes X of the continuously connected joints 30 at a desired bending angle θ, a pipe line curved along a desired curvature can be formed. As shown in FIG. 5, even when the pipe direction is bent, a part of the end 10E of the first protective tube 10 inserted into the first socket 31 is inserted into the socket enlarged diameter part 35. This allows the pipe to be accommodated in a space whose diameter has been enlarged, and it is possible to prevent the formation of a step in the conduit that would impede the insertion of a cable or the like. Therefore, it is possible to provide the joint 30 and piping structure 1 in which the direction of the pipe line can be freely adjusted and cables and the like can be easily inserted.

Note that the technical scope of the present invention is not limited to the embodiments described above, and various changes can be made without departing from the spirit of the present invention.

In addition, it is possible to appropriately replace the components in the embodiments with well-known components without departing from the spirit of the present invention. Furthermore, the above-described modifications may be combined as appropriate without departing from the spirit of the present invention.
For example, in the embodiment described above, a power cable is used as the cable inserted into the piping structure 1, but the cable is not limited to this, and a communication cable may also be used. A plurality of sheath tubes that accommodate cables may be inserted into the first protection tube 10, the second protection tube 20, and the joint 30 that constitute the piping structure 1. In this way, the piping structure 1 can be used not only as a power pipeline but also as a communication pipeline. However, the effects of the present invention are more effective when the piping structure 1 has local bends (large bends) like a power pipe.
Further, in the above embodiment, the joint 30 has the first socket 31 at one end and the first socket 32 at the other end, but the joint 30 is not limited to this, and the joint 30 has the first socket 31 at one end and the first socket 32 at the other end. Like the joints 30A to 30D according to the fourth modification, the joints 30A to 30D may have sockets at both ends. That is, in the joints 30A to 30D, a second socket 37 is provided at the other end 32a in place of the first socket 32. In this case, the shapes of the sockets at both ends may be the same as in the modified examples shown in FIGS. 10 to 13, or may be different shapes from these modified examples. For example, in the modified examples shown in FIGS. 10 to 13 Both the socket shapes at both ends may have the socket enlarged diameter part 35 as shown in FIG. good. When the sockets at both ends are provided with socket enlarged diameter parts 35, the total bending angle θ is 5.75° or less when the sockets at both ends are bent, thereby creating a piping structure 1 with a curvature of 5 mR. It is also possible to do this. In addition, when both ends are sockets, it is preferable that the first protection tube 10 and the second protection tube 20 are both straight tubes.

Here, the joints 30A to 30D shown in FIGS. 10 to 13 are used, for example, as joints for protection tubes 10 and 20 each having a nominal diameter of 100. Among these, a continuity test rod CM having a length of 500 mm can pass through the joints 30A to 30C shown in FIGS. 10 to 12.
In the joint 30A shown in FIG. 10, the bending angle θ at each of the first socket 31 and the second socket 37 is 5.75°, the inner diameter of the socket enlarged diameter part 35 is 124 mm or more, and the inner diameter of the intermediate enlarged diameter part 36 is 5.75 degrees. It is 142 mm or more. In addition, when aiming to pass a continuity test rod CM with a length of 500 mm, the effective length of the joint 30A (the distance between the ends of the protective tubes 10 and 20 (straight pipes) connected by the joint 30A) should be 400 mm or more. There is a need to. As a result, for example, by setting the length of the protection tubes 10, 20 (straight pipes) connected by the joint 30A to 600 mm, the sum of the joint effective length and the straight pipe is 1 m (1000 mm), and the joint 30A has a length of 11 mm. By bending .5 degrees (5.75 degrees x 2), a construction curvature of 5 mR can be achieved.
A joint 30B shown in FIG. 11 and a joint 30C shown in FIG. 12 are modifications of the joint 30A.
In the joint 30A shown in FIG. 10, the intermediate portion 33 includes two diameter changing portions 33a whose diameter gradually increases from the end in the tube axis X direction toward the center of the intermediate portion 33, and these two diameter changing portions 33a are directly connected at the center. On the other hand, in the joint 30B shown in FIG. 11, the intermediate portion 33 includes one straight pipe portion 33b in addition to the two diameter changing portions 33a. In the joint 30B, a straight tube portion 33b is arranged at the center of the intermediate portion 33, and diameter changing portions 33a are provided on both sides of the straight tube portion 33b in the tube axis X direction. Note that the inner diameter of the intermediate portion 33 at the center in the tube axis X direction does not need to be 142 mm or more. For example, another form that has a tapered structure (diameter changing part 33a) is adopted so that the inner diameter is 133 mm or more within 90 mm from the end of the intermediate part 33 in the tube axis X direction (the enlarged diameter part 35 of the socket) toward the center. It is possible to do so.
In the joint 30A shown in FIG. 10, the two diameter changing parts 33a (intermediate enlarged diameter parts 36) of the intermediate part 33 change in the radial direction of the joint 30A (in the paper) from the ends in the tube axis The diameter is expanded on both sides (direction). On the other hand, in the joint 30C shown in FIG. 12, in the illustrated cross section, the diameter changing portion 33a is only on one side in the radial direction from the end in the tube axis X direction toward the center (in the illustrated example, only on the upper side in the drawing). ). The diameter of the socket enlarged diameter portion 35 and the intermediate diameter enlarged portion 36 may be enlarged only on the outside of the bend of the pipe line formed by the piping structure 1, and may not be diameter enlarged on the inside of the bend.
Furthermore, a continuity test rod CM having a length of 400 mm can pass through the joint 30D shown in FIG. That is, the lengths of the continuity test rods CM that can be passed are different between the joints 30A to 30C shown in FIGS. 10 to 12 and the joint 30D shown in FIG. 13. In the joint 30D shown in FIG. 13, the effective length of the joint may be 250 mm or more, and the joint 30D can be made compact, making it possible to further reduce costs. An example of the joint effective length is, for example, the distance in the tube axis be done.

1 Piping structure 10 First protection tube 10E End 20 (of the first protection tube) Second protection tube 30, 30A, 30B, 30C, 30D Joint 30E End 31 (of the joint) First socket 31a (of the joint) One end 32 First spigot 32a Other end 33 (of the joint) Intermediate portion 34 Seal ring 35 Socket enlarged diameter portion 35T Tapered surface X Tube axis X1 Tube axis X2 Tube axis X3 Tube axis Y Intersection θ Bending angle

Claims (9)

A tubular fitting extending along a straight tube axis,
It has a first socket at one end into which the first protection tube is fitted, a first socket into which the second protection tube is fitted at the other end, and a connection between the first socket and the first socket. having an intermediate part in between;
The first socket has a socket expanding diameter part that increases in diameter from the one end toward the other end,
The first spigot has a uniform annular cross section along the tube axis,
The minimum inner diameter of the first socket is larger than the outer diameter of the first difference port,
The minimum inner diameter of the intermediate portion is smaller than the outer diameter of the joint. The joint according to claim 1, wherein a first length of the first socket along the pipe axis is equal to a second length of the first spigot along the pipe axis. The joint according to claim 1, wherein the socket enlarged diameter portion has an elliptical cross section. The joint according to claim 1, wherein the socket enlarged diameter portion has a tapered surface. The joint according to claim 1, wherein the intermediate portion has an elliptical cross section. The joint according to claim 1, wherein the intermediate portion has an intermediate enlarged diameter portion whose diameter increases as the distance from the one end increases. A piping structure including the joint according to any one of claims 1 to 6, comprising the first protection tube and the second protection tube. The piping structure including the joint according to claim 7, wherein the first protection tube or the second protection tube is a straight tube. The piping structure including the joint according to claim 7, wherein the first protection tube or the second protection tube has the same shape as the joint.

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