JP4416091B2 - Structure of pipe for fluid flow path - Google Patents

Description

The present invention relates to a structure of a long fluid flow pipe constituting a water and sewage system, various irrigation channels, and the like, and particularly relates to a structure suitable for a rehabilitation pipe provided inside an existing pipe.

Rehabilitation pipes are known. For example, there is a rehabilitation pipe through which a new rehabilitation pipe is passed while being destroyed from the inside (see Patent Document 1).
In addition, as such a correction pipe, it is also known to form a necessary long pipe by adding a plurality of unit pipes made of ceramic, metal or resin of a predetermined length in the length direction. In this case, adjacent unit pipes are used. In some cases, the end portions in the length direction are connected by a large-diameter screw joint (for example, see Patent Document 2).
Furthermore, there is also a joint in which a multi-threaded screw is formed in a thickened portion on the inner peripheral side and the outer periphery at the time of connection is made flush with a flat surface (for example, see Patent Document 3).
In addition, the unit tube is made of resin, and male and male joint portions are provided in the thickness of both end portions in the length direction, and the inner and outer peripheral surfaces are flush when connected (see Patent Document 4), a screw joint type metal tube The joint at the end is a taper screw, the tip of one side is a taper-shaped protrusion, and the other side is provided with a taper-shaped recess to which the taper-shaped protrusion fits, and the taper-shaped protrusion fits into the taper-shaped recess when screwed. There are also those that have improved sealing performance (see Patent Document 5).

JP 2001-271966 A JP 2004-270828 A Japanese Patent Laid-Open No. 10-311028 Japanese Utility Model Publication No. 4-124391 Japanese Patent Laid-Open No. 11-82829

Since the method of laying the correction pipe while destroying the existing pipe as in the above-mentioned Patent Document 1, it takes time to work, so in order to shorten the construction period and reduce the construction cost, the correction pipe into the existing pipe without breaking. Those that can be inserted smoothly are preferable.
However, if the joint part is larger than the outer diameter of one stage as in Patent Document 2, if it is going to be inserted into the existing pipe, it is necessary to make the outer diameter of the rehabilitated pipe smaller by the diameter of the joint part. Since the flow rate is reduced, it is required to eliminate such a large-diameter joint and make the outer peripheral surface flush when connected.
Moreover, since the flow rate is reduced by increasing the wall thickness on the inner peripheral side even if the outer surface of the joint part is flush as in Patent Document 3, the narrow part by such a joint is not formed. The inner peripheral surface at the time of connection is also required to be flush.
By the way, Patent Documents 4 and 5 relate to a metal pipe joint structure used for an application that must withstand high pressure such as an oil feeding pipe, and the joint in such an application maintains the seal of the connecting portion. Therefore, considerations such as welding or friction joining by applying high pressure are required, and a large-scale device is required.
On the other hand, for example, those having a sealing performance (0.5 MPa) to the extent required for five types of JIS standard internal pressure pipes are not required to have such a high sealing performance as realized by the large-scale facilities and operations. However, it is desirable to be able to connect quickly and easily by hand, and to achieve the sealing performance of the above standard.
For this purpose, it is conceivable to use a resin tube to couple with a multi-thread screw such as a four-thread screw.
However, in the case of using resin as in Patent Document 4, since the screw portion is originally provided with a clearance for enabling coupling, a seal member must be provided on the non-screw portion so as to close the clearance. However, the above-mentioned standard cannot be cleared only with such a seal, and it is necessary to block the clearance more reliably with a part other than the seal member.
Furthermore, if multi-threaded screws are used, quick screw connection work is possible, but if the seal projection is fitted into the seal groove using this screw connection, the seal projection moves in the axial direction. For multi-threaded screws with a small amount of stroke (hereinafter referred to as stroke amount), it is difficult to increase the seal pressure because the axial force applied to the seal protrusions is small, and it is difficult to increase the seal pressure. It was difficult to apply.
Further, as in Patent Document 5, a seal by fitting a tapered protrusion and a tapered groove is also conceivable. However, since the tapered groove is provided in the metal tube, the seal uses elastic deformation of the tapered groove. It is not intended to be increased by the above-mentioned large-scale device, and the axial force due to screw connection is simply increased by the above-mentioned large device, so that the pressure contact force on the taper surface is increased, so that the seal protrusion is axially connected when connecting a four-thread screw or the like. This method is not applicable to the case where the amount of movement (hereinafter referred to as stroke amount) is small, and it cannot be applied to applications where the connection is easily made by work.
Furthermore, using a separate known joint having a rubber seal and press-fitting the tip of the resin tube into it, a predetermined sealing performance can be obtained, but such press-fit connection requires a large force, After all, it cannot be applied to applications that are easily connected by hand. In addition, the above basic request to make the outer periphery of the connection flush with each other cannot be satisfied.
Therefore, the present invention uses a multi-threaded resin unit tube, allows easy connection by hand, and realizes a sealing performance that meets a predetermined standard. Objective.

In order to solve the above-mentioned problems, the invention according to claim 1 relating to the structure of a fluid flow path tube body is provided with a screw on the outer peripheral surface at one end in the length direction of a unit pipe of a predetermined length in order to form a fluid flow path. The formed male joint part is provided, the female joint part is formed on the other end side with a screw formed on the inner peripheral surface, and the male and male joint parts are respectively formed within the general thickness of the unit pipe. In the structure of the fluid flow channel tube in which the outer surface of the long tubular body at the time of connection is flush with the long tubular body by connecting multiple in the length direction,
The unit tube is made of resin, and the screw of the joint part of the male and female is a multi-threaded screw,
Provided on one side of the joint part of the male and female is a seal projection that protrudes in the axial direction with a tip having a tapered cross section, and on the other side is provided a seal groove into which this seal projection fits,
When the male and male joints are screwed together, the seal protrusion fits while expanding the seal groove.

According to a second aspect of the present invention, in the first aspect of the present invention, the male and female screws are engaged with four screw grooves formed approximately every ¼ circumference in the circumferential direction of each joint portion and the screw grooves 4. It is characterized in that it is a four-thread screw consisting of a screw thread.

A third aspect of the present invention is characterized in that, in the first aspect, the seal protrusion and the seal groove are formed on the radially inner side of the unit tube with respect to the screw portion.

A fourth aspect of the invention is characterized in that, in any one of the first to third aspects, a long tubular body to which the unit pipe is added is used as a correction pipe.

According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the male and female joint portions include a lock portion that prevents loosening when screw coupling is completed.

A sixth aspect of the present invention is the method according to any one of the first to fifth aspects, wherein the seal protrusion has a V-shaped cross section at a tip portion, the seal groove has a V-shaped cross section groove into which the seal protrusion is fitted, The opening angle of the seal protrusion in the V shape is larger than the opening angle of the seal groove in the V shape.

A seventh aspect of the present invention is characterized in that, in any one of the first to sixth aspects, a seal material is previously placed in the seal groove to seal between the tip of the seal protrusion and the seal groove.

The invention of claim 8 is characterized in that in any one of the above-mentioned claims 1 to 7, the unit tube is connected outside the manhole in a state of being held by hand and inserted into the manhole. .

According to the first aspect of the present invention, the unit pipe provided with the multi-thread is made of resin, and the female side joint part, male side joint part and seal part constituting the joint part are all formed within the general thickness of the unit pipe. Therefore, when a plurality of unit tubes are added and connected to form a long tube body, the outer surface of the long tube body can be formed flush. For this reason, even when interpolating into an existing pipe, the outer diameter of the long pipe can be made as close as possible to the inner diameter of the existing pipe, and the outer diameter of the long pipe can be increased accordingly. Can be easily secured, and the top surface is smooth, so that the interpolation work is smooth.
In addition, when connecting adjacent unit tubes at the joint, the seal is formed with an axial fitting structure, and the seal protrusion enters the resin seal groove while expanding it, so that the elastic deformation of the seal groove As a result, the seal protrusion is closely fitted to the wall surface of the seal groove, and a reliable sealing performance can be realized.
As a result, it is possible to quickly connect with a multi-thread screw while realizing a predetermined sealing performance, and it is possible to easily perform a connecting operation manually.

According to the second aspect of the present invention, since the joint portion is constituted by four threads, when the unit pipe is added, it can be quickly connected by screw connection only by making about 1/4 rotation. In addition, it is possible to work without turning it over just by twisting the hand by approximately 90 °, so that the screwing work becomes easy.
In addition, since the tightening limit can be grasped only by the amount of twist of the wrist, it is difficult to cause overtightening and insufficient tightening, and a high-precision connection is possible while enabling quick work.

According to the invention of claim 3, since the seal projection and the seal groove are formed on the radially inner side of the unit tube with respect to the threaded portion, the deformation that causes the outer peripheral surface to expand even when the seal groove is elastically deformed during connection. Therefore, the outer peripheral surface can be kept flush.

According to the invention of claim 4, the outer peripheral surface is smooth while maintaining the same surface, which is suitable for a correction pipe that is inserted into an existing pipe while being added.

According to the invention of claim 5, since the male and male joint portions are locked by the lock portion when the screw coupling is completed, it is possible to maintain high sealing performance by the seal groove and the seal protrusion which are prevented from loosening and elastically deformed.

According to the sixth aspect of the present invention, the seal protrusion and the seal groove each have a V-shaped cross section, and the opening angle forming the V shape of the seal protrusion is larger than the opening angle forming the V shape of the seal groove. The ratio of the amount by which the seal protrusion pushes into the seal groove sometimes increases and the ratio of the amount that pushes the seal groove is increased. Can be firmly attached. For this reason, the stroke amount of the seal protrusion can be relatively reduced, the protrusion amount of the seal protrusion can be reduced, and the seal groove can be shallowed.

According to the seventh aspect of the present invention, since the sealing material is put in the sealing groove, the sealing performance can be further improved.

According to the invention of claim 8, since the unit tube held by hand can be added and connected outside the manhole, the workability when working with a hand thrusting into a narrow place such as inside the manhole is possible. Can be improved.

Sectional drawing which shows the construction state of the correction pipe which concerns on 1st Example (FIGS. 1-7) A longitudinal sectional view along the axial direction of the unit pipe, A longitudinal sectional view showing a fastening state of the male side joint and the female side joint, The expanded sectional view of the A section (seal part) in FIG. An enlarged cross-sectional view of the male joint, An enlarged sectional view of the female joint, A diagram that explains the fastening of a male and female joint step by step The same figure as FIG. 1 which shows the state at the time of construction of the correction pipe which concerns on 2nd Example (FIGS. 8-17). Side view of unit tube, Perspective view showing the male joint from the front side The perspective view which fractures | ruptures a female side joint and shows the inner side from the back side Enlarged view of FIG. Axial sectional view of male and female joints of unit pipe Sectional drawing which shows the state before and after joining of a joint part Sectional drawing which shows the state before and behind the coupling | bonding of a thread part Cross-sectional view explaining the seal structure A diagram that explains the joint connection step by step

An embodiment will be described below with reference to the drawings. FIG. 1 is a cross-sectional view showing a construction state of an erecting pipe 1 having a long shape for correcting an existing pipe making an agricultural waterway.
The straightening pipe 1 is configured as a long pipe by connecting a large number of unit pipes 2 in the axial direction, and is inserted inside a pipe line 4 formed of an existing pipe 3 made of ceramics, for example. The existing pipe 3 is not limited to pottery but may be made of metal or resin. The pipe line 4 forms an agricultural irrigation channel to be corrected, and one end opens into a manhole 5 in a horizontal hole shape. Note that a felt tube 4a is inserted in advance in the conduit 4 over its entire length. The felt tube 4a is used for cushioning, and the outer diameter thereof is about the outer diameter of the conduit 4, the inner diameter is about the outer diameter of the correction tube 1, and the correction tube 1 is inserted into the felt tube 4a. . 6 is a ground surface, and 7 is a horizontal hole formed in the ground for embedding the existing pipe 3.

The correction pipe 1 is added in the manhole 5. Since one end of the correction pipe 1 protrudes from the pipe 4 in advance in the manhole 5, a continuous correction pipe 1 can be formed by successively adding new unit pipes 2 to the one end. 1 is fed from the manhole 5 into the horizontal hole-shaped pipe 4, the pipe 4 is corrected, and the correction pipe 1 becomes a new pipe. The length of the correction tube 1 can be freely adjusted depending on the number of unit tubes 2 to be added.

A male joint 10 and a female joint 20 each having four threads are formed at both ends of the unit tube 2, and a handle 9 b of the belt wrench 9 in which a belt 9 a is wound around an intermediate portion is grasped with a hand 8. A vertical hole-shaped manhole 5 is inserted from the upper opening, one end of the manhole 5 is fitted to the end of the correction pipe 1 protruding into the manhole 5, and the handle 9b is rotated to twist the unit pipe 2. The screw is coupled by rotating about 90 ° around the axis C.
As a result, the unit pipe 2 is connected to the correction pipe 1 and added, and becomes a new end portion thereof. If this is sent into the pipe line 4 and another unit pipe 2 is added an arbitrary number of times, A straightening pipe 1 made of a long pipe having a free length can be formed, and a new fluid flow path can be formed in the pipe 4.

The belt wrench 9 has a belt 9a made of nylon or the like in a ring shape at the tip of the handle 9b, and when the handle 9b is rotated by adjusting the length so that the belt 9a is fitted to the periphery of the unit tube 2 and then the handle 9b is rotated. This is a known tool capable of screwing the unit tube 2 together. By using this tool, it is possible to easily fasten the unit pipe 2 that is thick to some extent so that it cannot be grasped with one hand. The unit tube 2 of the present embodiment is set to have an outer diameter of 24.2 mm and a weight of 5.2 kg.

Here, if the inner diameter of the manhole 5 is D1, and the length of the unit tube 2 is D2, D2 <D1 in consideration of workability in the manhole 5. For example, the manhole is of a predetermined standard, and D1 = 90 cm and D2 = 65 cm. However, the inner diameter D1 of the manhole 5 can be arbitrarily set. The length D2 of the unit tube 2 is preferably set to be as long as possible within a range in which workability in the manhole 5 can be ensured, and can be freely set according to the inner diameter D1 of the manhole 5.

3a in the figure is a joint formed at one end of the existing pipe 3 in the axial direction, and has a larger diameter than the general outer diameter of the existing pipe 3. The outer diameter of the existing pipe 3 on the other end 3b side is a general outer diameter, but is relatively smaller than the joint 3a on the one end side, and is fitted and connected to the joint 3a of the adjacent existing pipe 3 A long pipe line is formed by joining.
In such a pipe line 4 that is added by simple fitting in the joint 3a, the seal at the joint portion is weak, and the risk of leakage from the connecting portion is increased.

In addition, if the pipe 4 of the existing pipe 3 is used for a long period of time, the existing pipe 3 itself may be damaged or deformed due to pressure fluctuations inside and outside, and this may cause trouble as a pipe such as a water channel. . However, in this embodiment, by newly inserting the correction pipe 1 into the inside of the pipe line 4 to which the existing pipe 3 is connected, the pipe line 4 by the existing pipe 3 is corrected to the pipe line by the correction pipe 1. The above obstacles can be eliminated.

Details of the unit tube 2 will be described below. 2 is a longitudinal sectional view along the axial direction of the unit tube 2, FIG. 3 is a longitudinal sectional view showing a fastening state of the male side joint 10 and the female side joint 20, and FIG. 4 is an enlarged view of a portion A (seal portion) in FIG. FIG. 5 is an enlarged sectional view of the male side joint 10, FIG. 6 is an enlarged sectional view of the female side joint 20, and FIG. 7 is a diagram for explaining the fastening of the male side joint 10 and the female side joint 20 step by step. .

In these drawings, the unit pipe 2 is a pipe made of FRP resin as a whole, specifically made of PBT reinforced with an appropriate fiber material such as glass fiber. A male joint 10 having four threads is formed on the outer periphery of one end of the unit tube 2 (see FIG. 10), and a female joint 20 having four threads on the inner periphery of the other end is formed. (See FIG. 11).
The intermediate portion in the length direction of the unit tube 2 is a general thick portion 30, and the outer diameter R1, the inner diameter R2, and the thickness T (general thickness) can be arbitrarily set. R1 is 242 mm, the inner diameter R2 is 226 mm, and the thickness T of the general thickness portion 30 is 8 mm. This type of resin straight pipe is relatively thin.

The outer diameter R1 is arbitrarily determined, but a size that can be easily held with one hand (for example, about 200 to 300 mm) is preferable from the viewpoint of improving workability. The inner diameter R2 and the wall thickness T are appropriately determined, but it is required to increase the inner diameter R2 and to reduce the wall thickness T as much as possible in consideration of securing a larger flow rate and securing pressure resistance against fluid pressure. It has been.

The wall thickness T needs to consider the material constituting the unit tube 2 and the pressure of the fluid flowing inside, but in this embodiment, the base resin is PBT, and appropriate reinforcing fibers such as glass fibers are used. It shall be about 15% filled. PBT is most preferable because sufficient joint strength can be obtained even when the thickness of the base resin is PBT is relatively small. However, the base material resin and the reinforcing fiber of the unit tube 2 can be various combinations of known materials, and the base material resin can be an appropriate thermoplastic resin such as polypropylene or polyethylene. The reinforcing fibers can be appropriately set from various known materials, preferably in the range of about 10 to 20%.

As shown in FIGS. 2 to 5, the male joint 10 is formed with a screw forming portion 18 that is thinner than the general thick portion by reducing the thickness of the outer peripheral side at one axial end portion of the unit tube 2. The tip end side of the screw forming portion 18 forms a thin end portion 11 which is a non-threaded portion in which the thickness of the outer peripheral side is further cut. Four screw grooves 12 are cut in the screw forming portion 18 in the circumferential direction from the outside in the radial direction.
Each screw groove 12 has a trapezoidal cross section, and is engraved so as to gradually deepen from the surface of the screw forming portion 18 to form the screw groove 12, and one screw groove 12 is 90 ° on the outer periphery of the screw forming portion 18. Formed with length. The shallow part of the screw groove 12 becomes an introduction part when the other thread is engaged.

A portion between the screw groove 12 and the thin end portion 11 forms a screw thread 13. This thread 13 is also formed into four strips, each of which is also formed by 90 °, and each end portion has a low height and becomes an introduction portion.
Further, as is apparent from FIG. 2, each of the four threads 13 is arranged so that an end in the circumferential direction of one thread 13 partially overlaps with another adjacent thread 13 in the axial direction. If the adjacent screw threads 13 partially overlap in the axial direction in this way, the coupling strength becomes high against the axial tension during the coupling.
The circumferential length of each screw thread 13 is about ¼ circumference on the outer circumference of the unit tube 2. In FIG. 2, three screw threads 13 are visible, and the remaining one is not visible on the back side.
The four-thread screw has a pitch of 7 mm and a lead of 28 mm.

The screw forming portion 18 is a small-diameter portion obtained by cutting the outer peripheral side thickness of the unit tube 2 so as to form a step 14, and the outer diameter R3 thereof has a relationship of R1> R3> R2. The step 14 forms an annular wall surface when viewed from the axial front end side of the male joint 10. The top surface of the screw thread 13 is the same height as the bottom (inner diameter portion) of the step 14, the bottom of the screw groove 12 is the same height as the outer peripheral surface of the thin end portion 11, and the outer diameter R4 is R3> R4> R2. If the thickness of the thin end portion 11 is T1, the depth of the screw groove 12 or the height of the thread 13 is T2, the height of the step 14 is T3, and the general thickness 30 is T, then T1 + T2 + T3 = T It becomes.

The distal end of the thin end portion 11 that is the axial distal end portion of the male joint 10 forms a seal protrusion 15 that protrudes longer than the screw groove 12. The tip cross-sectional shape of the seal protrusion 15 is a substantially V-shaped protrusion protruding in the length direction of the horizontal axial line J, and the angle formed with respect to the axial line J of the outer slope 16 and the inner slope 17 is The opening angle θ of the seal projection 15 which is an angle between the outer inclined surface 16 and the inner inclined surface 17 is 20 °, and the opening angle θ is 10 ° with respect to the axial line J. ing. However, the tip of the seal projection 15 is cut to form a cut portion 15a.
The axial line J is a line parallel to the axial line C and is a line indicating the axial direction.

The length of the seal protrusion 15 is the length from the bending point P that changes to the outer slope 16 and the inner slope 17 at the thin end portion 11 to the cut portion 15a at the tip, and is appropriately determined. In the case, it is 3.4 mm. Further, the thickness T1 of the thin end portion 11 is 2.1 mm. Further, a taper-shaped non-screw portion 19 is formed between the end of the screw and the general thick portion 30 in the screw forming portion 18. In this embodiment, the length is 13.2 mm and the tip is inclined by 1 °. It has become. Further, the boundary between the tapered non-threaded portion 19 and the general thick portion 30 is a step 14, and two lock projections 31 are integrally formed at an interval of 180 ° so that the locking projection 31 protrudes toward the tip side. Has been. As shown in the enlarged portion in FIG. 5, the locking protrusion 31 has a substantially triangular claw shape having an inclined surface 33a inclined in the rotation direction (B arrow direction) during tightening and a right-angle wall 34a orthogonal to the B arrow direction. I am doing.

As shown in FIGS. 2 to 4 and 6, the female joint 20 has a screw forming portion 28 formed at the other end of the unit tube 2, which is thinner than the general thick portion 30 formed by cutting the inner peripheral thickness. The tip end side of the screw forming portion 28 forms a thin end portion 21 which is a non-threaded portion whose inner peripheral thickness is further reduced. On the inner peripheral surface of the screw forming portion 28, four thread grooves 22 are cut in the circumferential direction from the radially inner side. A portion between the screw groove 22 and the thin end portion 21 forms a screw thread 23 formed relatively by the screw groove 22. These screw groove 22 and screw thread 23 are configured in the same manner as the screw groove 12 and screw thread 13 of the male joint 10, and can be screwed together.

The four-thread screw is the same as that of the male joint 10, and as is apparent from FIG. 2, each thread groove 22 of the four threads is another screw whose end in the circumferential direction of one screw groove 22 is adjacent. It arrange | positions so that it may overlap with the groove | channel 22 in an axial direction, and the circumferential direction length of each screw groove 22 is about about 1/4 circumference length in the outer periphery of the unit pipe | tube 2. As shown in FIG.
Also in the female side joint 20, the adjacent thread grooves 22 partially overlap in the axial direction, so that the coupling strength is high with respect to the axial tension during the coupling.
In FIG. 2, three screw grooves 22 are visible, and the other one is on the back side and is not visible.

A step 24 is formed between the screw forming portion 28 and the general thick portion 30, and a seal groove 25 is formed in the thickness of the step 24. The step 24 forms an annular wall surface when viewed from the axial front end side of the female joint 20. The seal groove 25 is for fitting the seal protrusion 15, and is engraved from the outside so as to form a V-shaped cross section in the length direction of the axial line J, and is formed on the entire circumference of the step 24. It is an annular groove and is opened axially outward, that is, toward the fitting direction of the seal protrusion 15.

The inner peripheral surface 23 of the thin end portion 21 is coincident with the crest diameter of the screw thread 13, and the crest diameter of the screw thread 22 is coincident with the outer diameter and the outer peripheral surface at the bottom of the screw groove 12, from the inner peripheral side of the step 24. It is located at the outer peripheral side and is located on the outer peripheral side from the step 24. By doing in this way, the seal groove 25 and the screw thread 22 can be simultaneously formed. However, as is apparent from FIG. 3, a slight clearance is formed between the outer periphery of the male joint 10 and the inner periphery of the female joint 20 to enable screw connection. The clearance in this example is 0.3 mm.
Here, in the female joint 20, if the thickness of the thin end portion 21 is T1, the height of the screw thread 22 is T2, the height of the step 24 is T3, and the thickness of the general thickness 30 is T, then male Similar to the side joint 20, T1 + T2 + T3 = T (see FIG. 6).

As shown in FIG. 3, the thin-walled end portion 21 is fitted to the outside of the tapered non-threaded portion 19 in the male joint 10 with a certain clearance, and therefore has a tapered shape corresponding to the non-threaded portion 19. Yes.

As shown in FIG. 6, two locking recesses 32 are integrally formed at the tip of the thin end portion 21 at intervals of 180 °. As shown in the enlarged portion in the figure, the locking recess 32 is formed in a notch shape from the front end surface to the axially inward (screw side), and the rotational direction of the male joint 10 during tightening (indicated by arrow B). ) And a right-angle wall 34b perpendicular to the direction indicated by the arrow B. When locked, the locking projection 31 enters the locking recess 32, and the right-angle walls 34a and 34b come into contact with each other and are locked. It has become.
It should be noted that the positions of the locking protrusion 31 and the locking recess 32 are formed at positions shifted by approximately 90 ° in the circumferential direction. The lock protrusion 31 and the lock recess 32 serve not only as a simple lock member but also as a positioning means during connection.

That is, in the case of a four-thread screw, the amount of rotation required for coupling differs greatly depending on the relationship between the screw thread positions of both unit pipes when connected. For example, the engagement start side end of the screw thread in one unit tube (tip tilted in the coupling direction) is inclined to the engagement end side (innermost side) of the screw thread in the other unit tube. If it is in the vicinity of the engagement start side end (front end closest to the front side) of the other screw thread, for example, it is first approximately 90 Rotate to move to the end of engagement end of the thread, move from here to the thread groove located on the back of the end of the engagement start side of the next thread, and further rotate 90 degrees to join the screw This will increase the amount of extra rotation. Therefore, if the locking protrusion 31 is connected by determining the position where the position of the locking recess 32 is shifted by approximately 90 ° in the circumferential direction by visual measurement, the locking protrusion 31 can be quickly connected by rotating approximately 90 °.

As shown in FIG. 4, the seal groove 25 has an opening angle θ = 20 ° with respect to the axial line J, and the outer wall surface 26 and the inner wall surface 27 are formed symmetrically with respect to the axial line J by 10 °. Has been. That is, the opening angle of the seal protrusion 15 and the seal groove 25 is the same.
The depth of the seal groove 25 is 4 mm longer than the seal protrusion 15, and the seal protrusion 15 is fitted into the seal groove 25 so that the outer inclined surface 16 and the outer wall surface 26 and the inner inclined surface 17 and the inner wall surface 27 are in contact with each other. As a result, the joint is sealed. This stage is an initial fitting state in which no special axial force is applied to the seal protrusion 15, and the Q point which is an intermediate point on the tapered surfaces of the outer slope 16 and the inner slope 17 is positioned in the opening of the seal groove 25. The bending point P is at a position 0.4 mm before the step 24, and the cut portion 15a is positioned 1 mm before the bottom portion 25a of the seal groove 25 (this position is referred to as an initial fitting position). To do).

That is, until the cut portion 15a reaches the initial fitting position, the seal projection 15 enters the seal groove 25 with almost no resistance, and the seal projection 15 and the seal groove 25 abut at the initial fitting position to seal the joint portion. The initial mating state is reached. At this time, the opening width w at the entrance of the seal groove 25 and the thickness width t of the portion Q of the seal projection 15 at this position are the same. In addition, a gap 36 larger than an interference 35 described later is formed between the point P and the point Q. The gap 36 is also for ensuring adjustment of the tightening allowance 35, and the point P does not yet enter the seal groove 25 even after the adjustment at the tightening allowance 35 is completed.

In addition, since a gap is formed between the cut portion 15a and the bottom portion 25a of the seal groove 25, the cut portion 15a is made to be a seal material by previously putting a seal material such as rubber packing (not shown) therein. Is pressed against the bottom 25a of the seal groove 25 to fill the gap, so that a stronger seal structure can be obtained in addition to the seal by the taper contact portion between the seal protrusion 15 and the seal groove 25.

As shown in FIG. 3, at this initial fitting position, a slight clearance is formed between the step 14 of the male joint 10 and the tip 21 a of the thin end 21 of the female joint 20. This clearance forms a tightening allowance 35. When the male joint 10 is tightened into the female joint 20 until the clearance of the tightening allowance 35 disappears, and the tip 21a of the thin end 21 abuts against the step 14, the initial fitting is performed. It is pushed further from the position.

At this time, the seal projection 15 has a portion from the Q point to the P point side into the seal groove 25, but the thickness width of this portion gradually expands more than t (matches the opening width w). 15 is fitted while pushing the seal groove 25 open, and the reaction force accompanying the elastic deformation of the seal groove 25 at this time causes the outer slope 16 and the inner wall surface 27 to be firmly in close contact with the outer wall face 26 and the inner slope 17. Increases sealing performance.
For this reason, due to the presence of the tightening allowance 35, it has a high sealing performance that can withstand an internal pressure of about 1.0 MPa, which is much higher than 0.5 MPa, which is a pressure resistance requirement required for JIS standard five types of internal pressure pipes. The above JIS standard can be easily cleared in terms of sealing performance even though it is made of resin.

In addition, if a sealing material is previously inserted between the seal protrusion 15 and the seal groove 25, the sealing performance is further improved and the internal pressure of about 1.0 MPa that sufficiently satisfies the pressure resistance requirements of the above five JIS standards can be obtained. Higher sealing performance than JIS standards can be realized with certainty, enabling sufficient sealing performance with safety in mind.
At this time, since the sealing material 40 only needs to be filled in advance into the sealing groove 25, it can be filled easily before screw connection, and the workability is excellent.
Note that, when the seal margin 35 has been eliminated, the seal protrusion 15 is fitted into the seal groove 25 up to the point P, and the reaction force from the seal groove 25 side increases accordingly, and this reaction force is in the loosening direction. Since they act so as to rotate relative to each other, when the sealing is completed, the locking projection 31 enters the locking recess 32 and locks to prevent loosening.

As shown in FIG. 6, the position of the seal groove 25 is provided at a position biased toward the inner peripheral side of the general thick portion 30, and the inner peripheral side thickness from the center of the bottom 25 a is about 2.5 mm. Yes, the outer circumference is 5.5 mm. Thus, by providing at a position where the thickness ratio is approximately 2: 1, the elastic deformation of the seal groove 25 is facilitated, and the influence of the elastic deformation on the outer peripheral side is reduced. In this case, the outer peripheral portion is thicker than the seal groove 25, and the outer wall surface 26 cannot be expected to be elastically deformed by the pressing of the seal projection 15, so that the inner wall surface 27 is mainly elastically deformed. That is, the seal groove 25 of the present embodiment is configured to elastically deform one side.

However, even in a type in which only one side is elastically deformed, a sufficient sealing performance is ensured. That is, when the unit pipe 2 is connected and laid in the ground as a long rectification pipe 1 (FIG. 1), a large force is frequently applied to the long rectification pipe 1 from inside and outside. For example, from the outside it is shocking due to the passing of the vehicle. Under pressure, an excessive flow rate exceeding the standard may temporarily flow from the inside, causing the internal pressure to rise rapidly. In either case, a large force is applied to the joint.

However, the seal in the long straight tube 1 is maintained by the fitting structure of the seal protrusion 15 and the seal groove 25, and when bending occurs due to the fluctuation of the force applied to the joint portion, the seal protrusion 15 and the seal groove This corresponds to bending by elastic deformation of 25. At this time, since the seal protrusion 15 and the seal groove 25 maintain a strong close relationship with each other, the sealing performance is sufficiently maintained.

Further, even if the internal pressure rises and the fluid tries to enter between the inner wall portion 27 and the inner inclined surface 17, both the inner wall portion 27 and the inner inclined surface 17 are pushed outward by the fluid pressure. The space between 17 is more firmly adhered to maintain the sealing performance. Even if a fluid enters between the inner wall 27 and the inner slope 17, the outer slope 16 is strongly pressed against the outer wall 26 by this penetration, so that the adhesion between the outer slope 16 and the outer wall 26 becomes strong, This part can be securely sealed.

In preparation for such a case, the sealing material can be put in the sealing groove 15 in advance to prevent fluid intrusion from between the inner wall 27 and the inner inclined surface 17 with certainty. Such an increase in sealing performance with a sealing material is necessary only in a special case such as a design with a high safety factor, and in a normal specification conforming to the JIS standard, a seal protrusion 15 and a seal not using such a sealing material are used. A seal with grooves 25 is sufficient.

As is apparent from FIG. 3, the step 24 protrudes to the inner peripheral side from the inner peripheral surface of the thin portion 11 of the male joint 10. Accordingly, a step is formed on the inner peripheral surface in the vicinity of the seal groove 25 at the connection portion between the two unit pipes. This is a necessary thickness for preventing the inner peripheral portion from being destroyed by elastic deformation of the seal groove 25. . Therefore, the step on the inner peripheral surface of the connecting portion is unavoidable, and the inner peripheral surface of the general thick portion 30 of the unit tube is connected from the male joint 10 on one side to the other female so that no step occurs on other portions. A taper is formed toward the side joint 20.

Next, the connection between the male side joint 10 and the female side joint 20 will be described. FIG. 7 is a cross-sectional view showing the coupling state step by step, A is a connection start state of two adjacent unit tubes 2, and the thin portion 11 of the male joint 10 is inserted into the female joint 20 and screwed. It is in a state where it is overlapped with the forming portion 28, and is still in a state where the screw connection between the four threads is not yet started. At this stage, the thread 13 of the male joint 10 contacts the outer side surface of the thread 23 of the female joint 20, and the insertion is stopped.

B shows a state when the four-thread screw is fastened. When the female joint 20 is rotated to the tightening side in A, the screw thread 13 of the male joint 10 comes into contact with the outer side surface of the screw thread 23 of the female joint 20. As it is guided in this state, it gradually enters the back while rotating in the circumferential direction, and when it eventually reaches the end of the screw thread 23, the end of this screw thread 23 is located deeper than the tip of the adjacent screw thread 23. Therefore, the screw thread 13 enters the screw groove 22 formed between the two screw threads 23 and 23, and the fastening with the four-thread screw is completed by the rotation of approximately 90.
In this state, the seal protrusion 15 is fitted into the seal groove 25 with almost no resistance and is in an initial fitting state, and the fastening allowance 35 is also maintained at a predetermined clearance.

C shows the seal completion state. When the male joint 10 is further rotated in the tightening direction in B, the seal protrusion 15 penetrates deeply while elastically deforming and expanding the seal groove 25, and the seal performance is suddenly improved and tightened. When the clearance of the margin 35 disappears, the male joint 10 and the female joint 20 are locked to each other, and relative rotation in the loosening direction is restricted.

D is an explanatory view of the lock, and until the sealing is completed, the male joint 10 rotates in the direction indicated by the arrow B, and the locking projection 31 slides the tip surface of the thin portion 21 of the mating female joint 20 by the inclined surface 33a. When it moves and eventually comes over the locking recess 32, the locking projection 31 enters the locking recess 32, and the right-angle walls 34a and 34b come into contact with each other and are locked.

In this state, although the stroke is relatively small due to the adoption of the four-thread screw, the internal pressure pipe defined in JISA5350 is formed by a strong seal in which the seal protrusion 15 and the seal groove 25 utilize elastic deformation. The pressure resistance performance of clearing the pressure resistance standard 0.5 MPa required for the five types with a margin is shown. The sealing performance can be evaluated by an internal pressure test defined in 8.1 of the above JIS.

Next, the operation of this embodiment will be described. As shown in FIG. 1, the unit pipe 2 is put into a manhole 5 and further inserted into a pipe line 4 by an existing pipe 3 having a horizontal hole shape. Subsequently, another unit pipe 2 is put into the manhole 5, and the end of the unit pipe 2 in the previous pipe line 4 is aligned with the male joint 10 and the female joint 20 so as to face each other. When the unit pipe 2 inserted into the pipe 4 is rotated, the unit pipe 2 in the pipe line 4 is screw-coupled and integrated by screw connection. The integrated pipe is fed into the pipe line 4, and is then renewed in the manhole 5. If the unit pipe 2 is added and the operation of feeding it into the pipe 4 is repeated, the long straightening pipe 1 can be easily laid in the pipe 4.

In this addition work, the operator holds the handle 9b of the belt wrench 9 with the belt 9a wound around the outer circumference of the unit pipe 2 with one hand 8 and puts it in the manhole 5, and the correction pipe 1 protruding into the manhole 5 If the end of the unit pipe 2 in the pipe line 4 forming the end is a female side joint 10, for example, the female side joint 20 of the unit pipe 2 to be newly added is fitted inside and outside and slightly rotated around the axis C. Thus, the phases of the thread groove 12 and the thread 22 are matched. Thereafter, when the unit pipe 2 to be newly added is rotated approximately ¼ rotation, that is, approximately 90 °, it is quickly coupled to the unit pipe 2 connected to one end of the correction pipe 1.
In addition, since the connection can be made at a rotation of approximately 90 ° at this time, the work can be easily performed in the relatively narrow manhole 5 and the work can be comfortably and quickly performed from the outside of the manhole 5.

In addition, the joint portion is sealed by fitting the seal projection 15 and the seal groove 25 by using the screw coupling force in the axial direction simultaneously with the screw coupling operation, so that the workability by the four-thread screw is improved. The sealability, which tends to be lowered, can be sufficiently compensated, and the improvement of workability by the four-thread screw and the maintenance / improvement of the sealability can be achieved at the same time.
In addition, a sufficiently high sealing performance can be realized by taper joining by fitting the seal protrusion 15 while elastically deforming and pushing open the seal groove 25.

At this time, by further tightening the tightening allowance 35 in the initial fitting state, the seal protrusion 15 can easily push open the seal groove 25, and the seal protrusion 15 The opposing slopes of the seal groove 25 can be firmly adhered. For this reason, even if the stroke amount of the seal projection 15 is relatively small even with a four-thread screw, the sealing performance can be obtained within a necessary and sufficient range, which is suitable for a four-thread seal structure. Moreover, as apparent from comparison with the second embodiment described later, since the opening angle θ of the seal projection 15 is relatively small, the outer inclined surface 16 and the inner inclined surface 17 and the outer wall surface 26 and the inner wall surface 27 are respectively formed. Since it becomes long, a contact area becomes large and a sealing performance improves.
Furthermore, if a sealing material is put in the sealing groove 25, the sealing performance can be reliably and further enhanced, and a high sealing performance sufficient for use can be realized even though it is made of resin.

In addition, the male joint 10 and the female joint 20 are thread grooves that form a four-thread screw by forming the apexes forming the V-shaped cross section of the seal protrusion 15 and the seal groove 25 so as to protrude in the axial direction. 12 and the thread 22, and the seal protrusion 15 and the seal groove 25 forming the seal portion can be provided in the general wall thickness T having relatively small dimensions, respectively. There is no need to enlarge.

For this reason, since the outer peripheral surface of the correction pipe 1 is flush with the outer surface of the general thick portion even at the joint portion of the adjacent unit pipe 2, the outer diameter of the correction pipe 1 is made equal to that of the existing pipe 3. The inner diameter can be made as close as possible.
As a result, even if the pipe is inserted into the existing pipe 3, the diameter of the straightening pipe 1 can be increased as much as possible, and a large flow rate can be secured. In addition, since the entire outer peripheral surface of the rectifying pipe 1 becomes smooth, it can be smoothly fed into the existing pipe 3 and the workability can be improved, particularly when inserted into the felt tube 4a. Therefore, it is suitable for rehabilitation pipes.

In addition, since the unit pipe 2 is made of resin, the entire correction pipe 1 connected to the unit pipe 2 is also made of resin, and can be manufactured at high speed by a resin molding method such as injection molding. Manufacture is easier and less expensive. In addition, since the weight can be reduced, handling becomes easier and workability is improved. In addition, since it is resistant to corrosion and the like, it is durable. For example, it has sufficient durability even when used in a flow path such as a sewer in which a strongly acidic fluid flows. Further, since the inner and outer surfaces can be smoothed, the flow resistance of the fluid flowing inside can be reduced.

Hereinafter, a second embodiment will be described with reference to FIGS. Since this embodiment is only partially different from the previous embodiment, common parts will be denoted by common reference numerals, and parts other than those requiring special description will be denoted by common reference numerals in the drawing and redundant description will be given. Shall be omitted.

FIG. 8 is a view similar to FIG. 1 showing a state at the time of construction. The unit tube 2 of this embodiment is formed with a male side joint 10 and a female side joint 20 each having four threads on both ends. The outer diameter is relatively thin and can be gripped by hand. Therefore, the middle part is grasped with the hand 8 and inserted into the vertical hole-shaped manhole 5 from the upper opening, and one end thereof is fitted to the end of the correction pipe 1 projecting into the manhole 5, and the grasping unit pipe 2 is held. Screwing is performed by twisting and rotating about 90 ° around the axis C. The length of the unit tube 2 and the dimensions of the manhole 5 are the same as in the previous embodiment.

In this way, since the joint portion is constituted by four-thread screws, when the unit pipe 2 is added, it can be quickly connected by screw connection only by making about 1/4 rotation. In particular, the work of inserting only the hand into the manhole 5 and connecting it to the outside of the manhole 5 is only the work of the hand which is difficult to visually check the connection part, but twisting about 90 ° which is the limit to return the wrist without difficulty. Since the fastening is completed in this manner, the workability is most suitable for the type that is inserted into the manhole of this type and connected from the outside.

In addition, since the fastening is completed at about 90 °, which is the limit to return the wrist comfortably, if the wrist is twisted back to about 90 °, the fastening will be done securely, and the fastening limit will be clear with the sense of the hand Thus, the fastening operation can be prevented from being finished with a twist smaller than about 90 °, so that the fastening accuracy is stabilized and the fastening failure can be prevented.

Details of the unit tube 2 will be described below. 9 is a side view of the unit tube 2, FIG. 10 is a perspective view showing the male side joint 10 of the unit tube 2 from the front side, and FIG. 11 is a cutaway view of the female side joint 20 of the unit tube 2 from the back side. FIG. 12 is an enlarged view of FIG. 9, in which the front side is shown in appearance and the back side is shown in an axial cross section. FIG. 13 is each axis of the male joint 10 and the female joint 20 of the unit tube 2. 14 is a sectional view showing a state before and after the joint portion is joined, FIG. 15 is a sectional view showing a state before and after the joining of the screw portion, FIG. 16 is a sectional view explaining the seal structure, and FIG. 17 is a joint portion. It is a figure explaining the coupling | bonding of step by step.

In these drawings, the male joint 10 is a four-thread screw similar to the previous embodiment, but a female-side joint 20 having four threads is formed on the inner periphery of the other end. The screw of the female joint 20 shown in FIG. 11 is different from the four-thread screw of the previous embodiment in that adjacent ones do not overlap and are relatively short in the circumferential direction.

In the middle portion of the unit pipe 2 in the longitudinal direction, the general thickness portion 30 has an outer diameter R1 of 140 mm, an inner diameter R2 of 129 mm, and a thickness T of 5.5 mm. It has become. The outer diameter R1 is arbitrarily determined, but a size that can be easily held with one hand (for example, about 200 mm) is preferable from the viewpoint of improving workability. The inner diameter R2 and the wall thickness T are appropriately determined, but it is required to increase the inner diameter R2 and to reduce the wall thickness T as much as possible in consideration of securing a larger flow rate and securing pressure resistance against fluid pressure. It has been.

The tip of the thin end 11 which is the axial tip of the male joint 10 forms a seal projection 15 that protrudes longer than the screw groove 12, and is thin and has an outer peripheral surface that matches the screw inner diameter of the general thick portion 30. . The cross-sectional shape of the tip of the seal projection 15 is a V-shaped projection protruding in the length direction of the horizontal axial line J, and the angles formed with respect to the axial line J of the outer slope 16 and the inner slope 17 are respectively The opening angle α of the seal projection 15 which is an angle between the outer slope 16 and the inner slope 17 is 60 °.

As shown in FIGS. 11 to 14, a seal groove 25 is formed in the step 24 in the female joint 20. The seal groove 25 is an annular groove formed on the entire circumference of the step 24 so as to form a V-shaped cross section in the length direction of the axial line J, and is opened outward in the axial direction. .
The seal groove 25 is formed at a position where the seal protrusion 15 is fitted when the male joint 10 and the female joint 20 are screwed together, but the angle of the outer wall surface 26 and the inner wall surface 27 with respect to each axial line J is 25 °. The opening angle β between the outer wall surface 26 and the inner wall surface 27 is as small as 50 ° with respect to 60 ° of the seal protrusion 15, and the seal protrusion 15 pushes the seal groove 25 and fits to increase the degree of adhesion. High sealing performance is obtained.

The thread 22 is formed by forming four threads at equal intervals in the circumferential direction so as to be engaged with the thread groove 12. A gap is formed between adjacent threads 22, and the circumference of the thread 22 is The direction length L2 is formed to be shorter than the circumferential length L1 of the portion that does not overlap in the axial direction of the screw groove 12, and when the female side joint 20 is combined with the male side joint 20, each thread 22 is a unit tube. Each of the screw grooves 12 can be engaged with each other by a slight angle adjustment for rotating the 2 around the axis C thereof. The screw thread 22 also has a trapezoidal cross section corresponding to the screw groove 12.

The inner peripheral surface 23 of the thin end portion 21 is coincident with the crest diameter of the screw thread 13, and the crest diameter of the screw thread 22 is coincident with the outer diameter and the outer peripheral surface at the bottom of the screw groove 12, from the inner peripheral side of the step 24. It exists in the position which entered the outer peripheral side, and is located in the outer peripheral side from the seal | sticker part 24a. By doing in this way, the seal groove 25 and the screw thread 22 can be simultaneously formed.

The circumferential lengths of the screw groove 12 and the screw thread 22 forming the four-thread screw will be described with reference to FIG. The circumferential length of the screw groove 12 is a, the overlapping length of the adjacent screw grooves 12 is b, the length between the ends of the adjacent screw threads 13, and the receiving width that forms a gap for receiving the screw threads 22 Is c, the circumferential length a of the screw groove 12 is slightly longer than the quarter circumference, and the receiving width c is about a quarter circumference. The overlapping length b of adjacent screw grooves 12 can be arbitrarily set by the circumferential length a of the screw grooves 12.

On the other hand, when the circumferential length of the screw thread 22 is d and the adjacent distance that is the distance between the adjacent screw threads 22 is e, the circumferential length d of the screw thread 22 is considerably shorter than the 1/4 circumferential length. The length f from the one end of the screw thread 22 to the one end of the adjacent screw thread 22 that is slightly longer than the adjacent distance e and is the sum of the circumferential length d of the screw thread 22 and the adjacent distance e is accepted. The width is about ¼ circumference which is about the same as c. In this way, when the male joint 10 and the female joint 20 are screwed together, each screw thread 22 is reliably received between the ends of the adjacent screw threads 13, and the screw groove can be quickly adjusted by slight adjustment. 12 can be engaged.

Next, the coupling state of the male side joint 10 and the female side joint 20 will be described. FIG. 14 is a cross-sectional view showing a state before and after coupling, where A is a state before two adjacent unit tubes 2 are connected, and B is a state after connection. FIG. 15 is a partial cross-sectional view illustrating the coupling between the screw groove 12 and the screw thread 22, where A indicates the screw groove 12 and the screw thread 22 that are separated before the coupling, and B indicates a state after the coupling. FIG. 16 is a partial cross-sectional view illustrating the fitting of the seal protrusion 15 and the seal groove 25. A is a separated state before the seal protrusion 15 is fitted to the seal groove 25, and B is the seal protrusion 15 being a seal. The state fitted to the groove 25 is shown. FIG. 17 is a view for explaining the coupling of the joint portions step by step.

As shown in FIG. 14A, the two unit tubes 2 are arranged in the axial direction, the male joint 10 of one unit tube 2 and the female joint 20 of the other unit tube 2 face each other, and one unit tube When two male joints 10 are fitted inside the female joint 20 of the other unit tube 2 and either one of the unit tubes 2 is rotated approximately ¼ around the axis C (see FIG. 12), As shown, the thread 22 is engaged with the thread groove 12 so that both unit tubes 2 are screwed together.

At this time, the entire seal protrusion 15 does not enter the seal groove 25 and a part of the seal protrusion 15 protrudes to the outside, and the distal end portion 21a of the thin end portion 21 of the female side joint 20 contacts the step 14 of the male side joint 10, The seal protrusion 15 fits into the seal groove 25, but a fastening allowance 35 is secured between the tip 21 a of the thin portion 21 and the step 14 of the male joint 10. A gap 36 larger than the fastening allowance 35 is formed between the step P of the maximum width portion of the seal projection 5 (that is, the bending point with the thin end portion 21) and the step 24.

As shown in FIG. 15A, among the inclined surfaces of the thread groove 12 and the thread 22, the tip (open end) side is designated as 12a and 22a, and the other side is designated as 12b and 22b. In order to enable screw connection, the actual thread groove 12 and the thread 22 are slightly different in size and are provided with backlash. In FIG. A, for convenience of explanation, the screw groove 12 and the screw thread 22 are shown separated vertically.

In the coupled state shown in B, a slight gap 28 is formed between the screw groove 12 and the screw thread 22. At the time of construction, both unit tubes 2 are pulled in opposite directions as indicated by arrows, so that the gap 28 is formed between the thread groove slope 12a and the thread slope 22b. This gap 28 becomes a cause of liquid leakage at the screw coupling portion. In particular, in the case of a four-thread screw that places importance on workability, the engagement length between the screw groove 12 and the screw thread 22 is shortened, so that the sealing performance is inevitably lowered.

Next, a seal structure by fitting the seal protrusion 15 and the seal groove 25 will be described with reference to FIG. As shown in A, in a state before the seal protrusion 15 is fitted into the seal groove 25, the opening angle α of the seal protrusion 15 is 60 °, the opening angle β of the seal groove 25 is 50 °, and α> β It has become. Therefore, when the male joint 10 and the female joint 20 are screwed together, as shown in B, the seal projection 15 advances along the axial line J due to the screw coupling force due to both screw couplings, and the outer wall surface 26 of the seal groove 25 is shown. And it fits, expanding the inner wall surface 27 outward.

For this reason, since the female joint 20 is made of resin, both the outer wall surface 26 and the inner wall surface 27 are elastically deformed and pushed open by the seal protrusion 15 pushed into a wedge shape, and the outer wall surface of the seal groove 25 is restored by its restoring force. 26 is in close contact with the outer slope 16 of the seal projection 15 and the inner wall surface 27 of the seal groove 25 with the inner slope 17 of the seal projection 15 to enhance the sealing performance. In addition, since the outer slope 16 and the outer wall surface 26 and the inner slope 17 and the inner wall surface 27 are respectively taper-coupled by a tapered surface, the sealing performance is further enhanced.

Note that the seal groove 25 of the present embodiment is a type in which both the outer wall surface 26 and the inner wall surface 27 are elastically deformed, and is a thin type unit in which the thickness of the general thick portion 30 on the outer peripheral side from the seal groove 25 is relatively thin. Made possible in the tube. In addition, since the wall surfaces on both sides of the seal groove 25 are elastically deformed, the wall surfaces on both sides can be efficiently elastically deformed when the seal protrusions 15 are made symmetrical.

In this way, the seal protrusion 15 and the seal groove 25 are each formed into a V-shaped cross section, and the outer slope 16 and the outer wall surface 26, the inner slope 17 and the inner wall surface 27 are formed with respect to the axial line J passing through the V-shaped apex. When provided symmetrically, in either case, even if a force is applied to the inside and outside across the axial line J due to fluctuations in the fluid pressure flowing in the unit tube 2 or impact applied from the outside of the unit tube 2, at least one side Since the taper surface can follow and deform while maintaining the sealing performance, the high sealing performance can be maintained even in applications where the force varies from the inside to the outside. It is possible to realize a high sealing performance in which a fluid pressure much higher than 0.5 MPa, which is a pressure resistance requirement of five kinds of JIS standards, can withstand an internal pressure of about 1.0 MPa.

In addition, the sealing performance can be further improved if the sealing material 40 having fluidity such as silicone resin is filled between the sealing protrusion 15 and the sealing groove 25 in advance. At this time, since the sealing material 40 only needs to be filled in advance into the sealing groove 25, it can be filled easily before screw connection, and the workability is excellent. In this embodiment, although it is made of resin, a high sealing performance that can reliably withstand an internal pressure of about 1.0 MPa, which is far higher than the pressure resistance requirements of the above five JIS standards, can be realized.

The opening angles α and β can be arbitrarily set as long as the relationship α> β is maintained. In particular, when the opening angle α is increased, the seal groove 25 can be elastically deformed sufficiently large to obtain the required sealing performance even if the stroke, which is the amount of movement of the seal protrusion 15 in the screw connection by the four-thread screw, is not so large. Therefore, it is effective for multi-threaded screws such as 4-threaded screws with a small stroke. Further, the shape is not limited to the symmetrical V-shape, and may be an asymmetrical shape having a slope on only one of the inside and the outside, and the seal groove 25 side may have a substantially square or semicircular cross section.

Furthermore, the sealing material 40 is not limited to a liquid material but may be a solid member such as packing or O-ring. In this case, it is only necessary to put the solid sealing material 40 in the sealing groove 25 in advance, so that workability is further improved.

FIG. 17 is a diagram showing the state when the male side joint 10 and the female side joint 20 are coupled step by step, and A is a state before the screw coupling. When the thin portion 11 of the male joint 10 is inserted into the thin portion 21 of the female joint 20 in this state, the screw thread 13 of the male joint 10 is in contact with the outer side of the screw thread 23 in the female joint 20. It becomes the state of.
In the state B, only the seal protrusion 16 enters the seal groove 25 without resistance at the tip end side, but has not yet reached a state where the seal groove is elastically deformed.

C is a state in which the screw connection by the four-thread screw is finished, and the seal protrusion 15 is fitted into the seal groove 25 while elastically deforming the outer wall surface 26 and the inner wall surface 27 of the contact portion, but is still sufficiently fitted. However, an initial fitting state in which a fastening allowance 35 is formed between the step 14 and the tip 21a of the thin portion 21 is obtained.
D is a seal completion state, and when the male joint 10 is tightened until the tightening allowance 35 is eliminated in C, the seal protrusion 15 is sufficiently deformed by elastically deforming the seal groove 25 and expanding the outer wall surface 26 and the inner wall surface 27. Fits deeply into the surface to achieve high sealing performance.

Next, the operation of this embodiment will be described. As shown in FIG. 8, the unit pipe 2 is put into the manhole 5 and further inserted into the pipe line 4 by the existing pipe 3 having a horizontal hole shape. Subsequently, another unit pipe 2 is put into the manhole 5, and the end of the unit pipe 2 in the previous pipe line 4 is aligned with the male joint 10 and the female joint 20 so as to face each other. When the unit pipe 2 inserted into the pipe 4 is rotated, the unit pipe 2 in the pipe line 4 is screw-coupled and integrated by screw connection. The integrated pipe is fed into the pipe line 4, and is then renewed in the manhole 5. If the unit pipe 2 is added and the operation of feeding it into the pipe 4 is repeated, the long straightening pipe 1 can be easily laid in the pipe 4.

In this addition work, the operator holds the outer circumference of the unit tube 2 with one hand 8 and puts it into the manhole 5 and rotates it approximately 1/4 turn, that is, approximately 90 °, to quickly connect to one end of the correction tube 1. be able to. For this reason, since it can connect by rotation of about 90 degrees, it can connect without turning over a hand. At a rotation angle exceeding 90 °, such as a triple thread, it is necessary to turn the hand over, but turning the hand put into the manhole 5 from the top is quite painful and time-consuming work. Can be done comfortably and quickly.

Simultaneously with the coupling of the four-thread screw, the seal protrusion 15 enters the seal groove 25 to form a seal. At this time, since the opening angle α of the seal protrusion 15 is relatively large and larger than the opening angle β of the seal groove 25, the ratio of the amount of opening the seal groove 25 to the stroke amount of the seal protrusion 15 increases, and the The seal protrusion 15 is fitted while the seal groove 25 is pushed open, so that the opposed inclined surfaces of the seal protrusion 15 and the seal groove 25 can be firmly adhered.

For this reason, the stroke amount of the seal protrusion 15 can be made relatively small, which is suitable for a four-thread screw, the protrusion amount of the seal protrusion 15 can be reduced, and the seal groove 25 can be made shallow.
Further, by filling the sealing groove 25 with the sealing material 40, the sealing performance can be further enhanced, and a high sealing performance sufficient for use can be realized even though it is made of resin.

Further, by providing the seal protrusion 15 and the seal groove 25 within the thickness of the general thickness portion 30, it is not necessary to increase the inner diameter of the correction pipe 1 at the joint portion, and the inner diameter can be made as much as possible. The large flow rate can be achieved without forming a narrow part inside the joint part.
As a result, even if the pipe is inserted into the existing pipe 3, the diameter of the straightening pipe 1 can be increased as much as possible, and a large flow rate can be secured, which is suitable for the rehabilitation pipe.

In addition, this invention is not limited to the said Example, It can apply variously, For example, a pipe line is not only the use as a rehabilitation pipe | tube, but the pipes for various fluids, such as a general water supply and sewage system and a civil engineering business Available to: Further, the dimensions such as the outer diameter and inner diameter of the unit pipe, the general wall thickness, pressure resistance, etc. can be arbitrarily set according to the purpose of use. Further, the first and second embodiments can be appropriately combined because the constituent parts are not independent of each other so that they cannot be used with each other.
Moreover, the screw provided in a joint part does not necessarily need to be a 4 item | strip | line screw, and it is sufficient if it is a multiple item | strip | row screw more than two.
Furthermore, the standard of the sealing performance is not necessarily limited to the JIS standard grade (5 types), and may be a grade that requires equivalent sealing performance in other standards.

1: correction pipe, 2: unit pipe, 10: male side joint, 11: thin part, 12: screw groove, 13: screw thread, 15: seal projection, 18: screw forming part, 20: female side joint, 21: Thin part, 22: screw groove, 23: screw thread, 25: seal groove, 28: screw forming part, 30: general thick part

Claims (8)

In order to form a fluid flow path, a male joint part having a screw formed on the outer peripheral surface is provided on one end side in the length direction of the unit tube of a predetermined length, and a female joint part having a screw formed on the inner peripheral surface on the other end side The male and female joints are each formed within the general thickness of the unit pipe, and a plurality of unit pipes are added in the length direction to form a long pipe body, and the outer surface of the long pipe body when connected In the structure of the fluid flow path tube body that is made to be flush with each other,
The unit tube is made of resin, and the screw of the joint part of the male and female is a multi-threaded screw,
Provided on one side of the joint part of the male and female is a seal projection that protrudes in the axial direction with a tip having a tapered cross section, and on the other side is provided a seal groove into which this seal projection fits,
A structure of a fluid flow channel body, wherein when the male and female joint portions are screwed together, the seal protrusions are fitted while expanding the seal groove. The male and female screws are four-threaded screws comprising four screw grooves formed approximately every ¼ turn in the circumferential direction of each joint portion and four screw threads engaging with the screw grooves. 2. The structure of a fluid flow channel tube according to claim 1, wherein 3. The fluid channel structure according to claim 1, wherein the seal protrusion and the seal groove are formed radially inside the unit tube with respect to the screw portion. 4. The fluid channel structure according to any one of claims 1 to 3, wherein a long tubular body to which the unit pipe is added is used as a correction pipe. 5. The fluid channel structure according to claim 1, wherein the male and female joint portions each include a lock portion that prevents loosening when screw connection is completed. The seal protrusion has a V-shaped cross-section at the tip, the seal groove has a V-shaped cross-section groove into which the seal protrusion is fitted, and the V-shaped opening angle of the seal protrusion has a V-shape of the seal groove. The structure of the pipe for fluid passages according to any one of claims 1 to 5, wherein the structure is larger than an opening angle. 7. The fluid channel tube structure according to any one of claims 1 to 6, wherein a sealing material is previously placed in the sealing groove to seal between the tip of the sealing protrusion and the sealing groove. The pipe for a fluid flow path according to any one of claims 1 to 7, wherein the unit pipe is connected outside the manhole in a state of being held by hand and inserted into the manhole. Construction.

Images