JP2021195966A - Pipe coupling structure - Google Patents

Abstract

To simplify construction and ensure sufficient tensile strength while minimizing machining of a pipe or a member to be united.SOLUTION: A pipe coupling structure is provided with an outer peripheral groove 21 extending over a total circumference of an outer peripheral surface is provided on an outer peripheral surface of an insertion cylinder portion 2A of a cylindrical joint 2, and an inner peripheral groove 11 extending over a total circumference of an inner peripheral surface and a C-shaped fit-in ring 3 that is fitted with the outer peripheral groove 21 and the inner peripheral groove 11 in the circumferential direction to couple pipes, on an inner peripheral surface of an end portion of a pipe 10. The outer peripheral groove 21 has a fastening groove portion 24 that has depth dimensions not less than height dimensions of the C-shaped fit-in ring 3, and groove width dimensions not less than width dimensions of the C-shaped fit-in ring 3, and a tensioning groove portion 25 that decreases depth dimensions toward a direction separating from the fastening groove portion 24 in a pipe axis direction.SELECTED DRAWING: Figure 3

Description

The present invention relates to a pipe connecting structure.

Conventionally, a long mirror bolt method has been used for the purpose of preventing the mirror surface from collapsing when excavating a tunnel on soft ground. As for the mirror bolts used in such a long mirror bolt method, a plurality of mirror bolts are driven into the cross section of the face of the tunnel so that a steel pipe (hereinafter, simply referred to as a pipe) has a depth of a predetermined length.
Welding is the first conceivable technique for joining small-diameter steel pipes (pipes) used for ground reinforcement of tunnels or slopes and civil engineering work such as foundation piles in the pipe axis direction. However, in the case of joining by welding, there are problems such as the quality is affected by the weather, environment, and the skill of the welder, the shortage of welders, and the length of welding time. In many cases, mechanical joints that can be connected to each other are used.

The following joint types (1) to (3) are known as typical configurations of mechanical joints.
The joint type (1) has a structure in which a male screw is machined on the outer surface of the steel pipe, a female screw is machined on the inner surface, and both male and female threads are screwed. Alternatively, there is also a structure in which steel pipes machined with male threads are connected to each other by a coupler with machined female threads. In the case of the joint type (1), it is often difficult to directly thread the steel pipe because the wall thickness is thin in the small diameter steel pipe.
The joint type (2) is a structure in which a coupler, an inner pipe, or the like is connected via a joint member. In this case, it is necessary to connect the joint member and the steel pipe with screws, bolts, etc., but it takes time to tighten the threaded joint, and the cross section of the steel pipe or joint is lost with bolts, so sufficient tensile strength of the joint is secured. It's hard to do.
The joint type (3) is a structure in which a separately processed joint is attached to a steel pipe by factory welding. In this case, it is necessary to process bolt holes and weld the steel pipe in advance, and it is costly to procure parts other than the steel pipe and the joint such as bolts and adhesives.

On the other hand, as a joint structure corresponding to the above-mentioned problems such as the joint types (1) to (3), a one-touch joint using a C-shaped fitting ring is known (see, for example, Patent Document 1). ).
11 (a) to 11 (d) are examples of the one-touch joint 100, and show a cross-sectional view of a main part of the C-shaped fitting ring 103. The one-touch joint 100 includes a pipe 101, a joint member 102 inserted inside the pipe 101, and a C-shaped fitting ring 103 that fits into both the pipe 101 and the joint member 102. On the outer surface 102a of the joint member 102 and the inner surface 101a of the pipe 101, storage grooves 104 and 105 in which the C-shaped fitting ring 103 is accommodated at the time of fastening the pipe are pre-processed over the entire circumference in the circumferential direction of the pipe.

As shown in FIGS. 11A to 11D, as an example of the fastening method of the one-touch joint 100, first, the C-shaped fitting ring 103 is set in the outer peripheral storage groove 104 of the joint member 102, and the pipe of the pipe 101 is piped. The joint member 102 is inserted from the end. A tapered surface or a curved surface is formed in advance at the pipe end of the pipe 101, and when the C-shaped fitting ring 103 hits the pipe end, the diameter of the C-shaped fitting ring 103 gradually shrinks along the tapered surface. The diameter is set to be equal to or smaller than the inner diameter of the pipe 101. As a result, the C-shaped fitting ring 103 is not caught on the inner surface of the pipe 101, and the joint member 102 is inserted.
Then, when the joint member 102 is inserted as it is and the C-shaped fitting ring 103 reaches the inner peripheral storage groove 105 on the inner surface of the pipe 101, the reduced diameter C-shaped fitting ring 103 is restored to the original diameter. Then, it becomes larger than the inner diameter of the return pipe 101. As a result, the C-shaped fitting ring 103 is fitted into both the outer peripheral storage groove 104 and the inner peripheral storage groove 105, and even if the joint member 102 is pulled, the C-shaped fitting ring 103 remains in both storage grooves 104 and 105. The pipe 101 and the joint member 102 are connected to each other without coming off by hooking on the pipe 101.

Japanese Unexamined Patent Publication No. 2004-190758

However, in the conventional pipe connecting structure using a one-touch joint, the pipes can be easily connected to each other by a simple structure, for example, but there is a problem that the tensile strength is small with respect to the pipe.

Here, FIGS. 11A to 11D show the behavior of the joint member 102 and the pipe 101 when a tensile load is applied to the one-touch joint 100. When a tensile load (in the direction of arrow F in FIG. 11) acts on the pipe 101, the C-shaped fitting ring 103 comes into contact with one wall surface 104a of the outer peripheral storage groove 104 of the joint member 102 as shown in FIG. 11 (b). .. At this time, as shown in FIGS. 11 (c) and 11 (d), one wall surface 104a is crushed by the C-shaped fitting ring 103, and the diameter of the C-shaped fitting ring 103 is reduced to the groove of the outer peripheral storage groove 104. A rotational force acts in the direction of sinking to the bottom (arrow P1 direction). As a result, the pipe 101 is lifted to the outside of the C-shaped fitting ring 103, moves along the outer surface 102a and is separated from the pipe 101, and the connection between the pipe 101 and the joint member 102 is disconnected.

Therefore, in the one-touch joint, the C-shaped fitting ring 103 is required to resist the tensile load and increase the tensile strength, and there is room for improvement in that respect.

The present invention has been made in view of the above-mentioned problems, and is a pipe connecting structure capable of being easy to construct and ensuring sufficient tensile strength while minimizing the processing of pipes and members to be connected. The purpose is to provide.

In order to achieve the above object, in the pipe connecting structure according to the present invention, a pipe connecting structure for connecting a pair of the pipes on a coaxial line via a cylindrical joint having an insertion cylinder portion to be inserted into the end of the pipe at both ends. The outer peripheral surface of the insertion cylinder portion has an outer peripheral groove extending over the entire circumference of the outer peripheral surface, and the inner peripheral surface of the end of the pipe extends over the entire circumference of the inner peripheral surface. The outer peripheral groove is provided with a C-shaped fitting ring that is fitted into each of the outer peripheral groove and the inner peripheral groove in the circumferential direction to form a pipe connection state, and the outer peripheral groove is the C-shaped. A fastening groove having a depth dimension equal to or greater than the height dimension of the fitting ring and a groove width dimension equal to or greater than the width dimension of the C-shaped fitting ring, in a direction separated from the fastening groove portion in the pipe axial direction. It is characterized by having a groove portion for tension whose depth dimension becomes smaller toward the surface.

In the pipe connecting structure according to the present invention, in a state where the pipe and the cylindrical joint are fastened, the inner peripheral groove formed in the pipe and the outer peripheral groove formed in the insertion cylinder portion of the cylindrical joint are formed into the fastening groove portion. The C-shaped fitting ring is fitted. When a tensile load acts on the pipe, the C-shaped fitting ring moves from the fastening groove portion of the outer peripheral groove to the tensile groove portion. At this time, since the depth dimension of the tension groove portion is set to be smaller in the direction away from the fastening groove portion, the groove bottom of the tension groove portion is located on the inner peripheral side of the C-shaped fitting ring. There is no space to move or deform inward in the radial direction of the C-shaped fitting ring, and the ring is supported from the bottom of the groove. Therefore, in the C-shaped fitting ring, the rotational force is suppressed from acting in the direction of sinking into the groove bottom of the fastening groove portion, and the rotational force acts in the direction of entering the inner peripheral groove.
That is, since the C-shaped fitting ring on which the rotational force acts restricts the movement of the pipe in the pulling direction, the tensile strength of the pipe connecting structure can be improved. As a result, even if the pipe is lifted to the outside of the C-shaped fitting ring, it moves beyond the C-shaped fitting ring in the direction of coming out along the outer peripheral surface of the cylindrical joint, making it difficult to separate from the pipe. It is possible to prevent the connection with the cylindrical joint from being disconnected.

As described above, in the present invention, the C-shaped fitting ring housed in the outer peripheral groove is a fastening groove portion in which a space is secured for the C-shaped fitting ring to sink to the lower part when the pipe and the cylindrical joint are fastened. Is used, and when a tensile load is applied to the pipe, a tension groove that closes the space on the inner peripheral side of the C-shaped fitting ring is used, and the outer groove has two functions, and two functions are effective depending on the situation. Can be used properly.
As described above, in the present invention, the construction can be easily performed with a simple structure that minimizes the processing of the pipes and members to be connected.

Further, the pipe connecting structure according to the present invention is a pipe connecting structure in which a pair of the pipes are connected to each other on a coaxial line via a cylindrical joint having an outer fitting tubular portion into which an end portion of the pipe is inserted at both ends. The inner peripheral surface of the outer fitting cylinder portion has an inner peripheral groove extending over the entire circumference of the inner peripheral surface, and the outer peripheral surface of the end of the pipe extends over the entire circumference of the outer peripheral surface. The outer peripheral groove is provided with a C-shaped fitting ring that is fitted into each of the inner peripheral groove and the outer peripheral groove in a circumferential direction to form a pipe connected state, and the inner peripheral groove is the C-shaped fitting. A fastening groove having a depth dimension equal to or larger than the height dimension of the built-in ring and a groove width dimension equal to or larger than the width dimension of the C-shaped fitting ring, and a direction away from the fastening groove portion in the pipe axial direction. It is characterized by having a groove for tension having a small depth dimension.

In the pipe connecting structure according to the present invention, in a state where the pipe and the cylindrical joint are fastened, the outer peripheral groove formed in the pipe and the inner peripheral groove formed in the outer fitting cylinder portion of the cylindrical joint are connected to the fastening groove portion. A C-shaped fitting ring is fitted into the. When a tensile load acts on the pipe, the C-shaped fitting ring moves from the fastening groove portion of the inner peripheral groove to the tensile groove portion. At this time, since the depth dimension of the tension groove portion is set to be smaller in the direction away from the fastening groove portion, the groove bottom of the tension groove portion is located on the outer peripheral side of the C-shaped fitting ring, and C. There is no space to move or deform in the radial direction of the character fitting ring, and the ring is supported from the bottom of the groove. Therefore, in the C-shaped fitting ring, the rotational force is suppressed from acting in the direction of sinking into the groove bottom of the fastening groove portion, and the rotational force acts in the direction of entering the outer peripheral groove.
That is, since the C-shaped fitting ring on which the rotational force acts restricts the movement of the pipe in the pulling direction, the tensile strength of the pipe connecting structure can be improved. As a result, even if the pipe goes down inside the C-shaped fitting ring, it moves beyond the C-shaped fitting ring in the direction of coming out along the inner peripheral surface of the cylindrical joint, making it difficult for the pipe to come off. It is possible to prevent the member from being disconnected from the member of the cylindrical joint.

As described above, in the present invention, the C-shaped fitting ring housed in the inner peripheral groove is for fastening in which a space is secured for the C-shaped fitting ring to sink to the lower part when the pipe and the cylindrical joint are fastened. A groove is used, and when a tensile load is applied to the pipe, a tension groove that closes the space on the outer peripheral side of the C-shaped fitting ring is used, and the inner groove has two functions, depending on the situation. Can be used properly.
As described above, in the present invention, the construction can be easily performed with a simple structure that minimizes the processing of the pipes and members to be connected.

Further, in the pipe connecting structure according to the present invention, the first groove width dimension Lc of the fastening groove portion and the second groove width dimension Lt of the tension groove portion are the total width dimension of the C-shaped fitting ring in the pipe axis direction. It is preferable to satisfy the relations of the equations (1) and (2) with respect to Lr.

In this case, the center of gravity of the C-shaped fitting ring can be supported by the groove bottom of the tension groove portion, and a rotational force acts in the direction in which the C-shaped fitting ring sinks into the groove bottom of the fastening groove portion. This can be suppressed more reliably.

Further, in the pipe connecting structure according to the present invention, the first groove depth dimension Hp at the end of the pipe, the second groove depth dimension Hc of the fastening groove portion in the cylindrical joint, and the third groove portion for tensioning. It is preferable that the groove depth dimension Ht satisfies the relationship of the equations (3) to (5) with respect to the height dimension Hr of the C-shaped fitting ring.

In the present invention, when a tensile load is applied to the pipe, the C-shaped fitting ring is easily caught in the inner peripheral groove of the pipe and the outer peripheral groove of the cylindrical joint and easily locked, and resists the tensile load of the pipe. Can be done.

According to the pipe connecting structure of the present invention, it is possible to secure sufficient tensile strength while being easy to construct while minimizing the processing of the pipes and members to be connected.

It is a vertical sectional view which shows the pipe connection structure by 1st Embodiment of this invention. It is a top view of the C-shaped fitting ring. It is an enlarged view of the main part which shows the fitting state of the C-shaped fitting ring shown in FIG. It is a vertical sectional view which shows the pipe connection structure when a tensile load is applied. It is an enlarged view of the main part which shows the fitting state of the C-shaped fitting ring, (a) is the figure before the action of the tensile load, and (b) is the figure of the state where the tensile load is applied. It is an enlarged view of the main part which shows the fitting state of the C-shaped fitting ring when a tensile load is applied, and is the figure corresponding to FIG. (A) to (d) are vertical cross-sectional views showing the behavior of the C-shaped fitting ring when a tensile load is applied. It is a figure which shows the tensile test result by an Example. It is a vertical sectional view which shows the pipe connection structure by 2nd Embodiment. It is a vertical cross-sectional view which shows the outer peripheral groove of the pipe connection structure by a modification. (A) to (d) are vertical cross-sectional views showing the behavior of the C-shaped fitting ring when a conventional tensile load is applied.

Hereinafter, the pipe connection structure according to the embodiment of the present invention will be described with reference to the drawings.

(First Embodiment)
As shown in FIG. 1, the pipe connecting structure 1 according to the present embodiment is, for example, a joint structure in which pipes 10 (10A, 10B) to be driven into the ground are fastened to each other via a cylindrical joint 2 in the pipe axis O direction. The pipe connection structure 1 of the present embodiment is a one-touch joint capable of easily connecting the pipes 10A and 10B to each other by human power.

The pipe connecting structure 1 is a joint structure in which a pair of pipes 10A and 10B are connected to each other on a coaxial line via a cylindrical joint 2 having an insertion cylinder portion 2A inserted into the pipe end portion 10a of the pipe 10 at both ends.

The pipe connecting structure 1 extends over the entire circumference of the outer peripheral groove 21 extending over the entire circumference of the outer peripheral surface 2a of the insertion cylinder portion 2A in the cylindrical joint 2 and the inner peripheral surface 10b of the pipe end portion 10a of the pipe 10. It is provided with an inner peripheral groove 11 and a C-shaped fitting ring 3 that is fitted into each of the outer peripheral groove 21 and the inner peripheral groove 11 in the circumferential direction to form a pipe connected state.

Here, in the following description, in the pipes 10A and 10B and the cylindrical joint 2, the direction of orbiting around the pipe axis O when viewed from the respective pipe axis O direction is referred to as the circumferential direction, and is orthogonal to the respective pipe axis O direction. The pipe axis O side is referred to as the inner peripheral side and the inner surface, and the inner peripheral side and the opposite side of the inner surface are referred to as the outer peripheral side and the outer surface.

The C-shaped fitting ring 3 shown in FIG. 2 has a substantially rectangular cross-sectional shape (see FIGS. 1 and 3), and a ring opening 3a is formed in a part of the ring shape in the circumferential direction. There is. The C-shaped fitting ring 3 can be elastically deformed so as to reduce the diameter and increase the diameter in the radial direction by opening and closing the ring opening 3a. The outer diameter of the C-shaped fitting ring 3 is set to be larger than the inner peripheral surface 10b of the pipe 10 shown in FIG.

The pipe 10 (10A, 10B) is made of, for example, STK400, and is applied to a short steel pipe having a pipe outer diameter of 114.3 mm and a pipe inner diameter of 102.6 mm (for example, a length of about 3 m). The pipe 10 is used for the purpose of the reinforcing method for driving into the ground, but may be used for other purposes. As the pipe 10, for example, a carbon steel pipe for general structure, a carbon steel pipe for building structure, or the like can be used.

As shown in FIG. 3, an inner peripheral groove 11 having a rectangular cross section extending over the entire circumference is formed on the inner peripheral surface 10b on the pipe end portion 10a side of the pipe 10. A C-shaped fitting ring 3 is fitted to the inner peripheral groove 11 with the outer peripheral groove 21 described later. Then, when the C-shaped fitting ring 3 is fitted between the inner peripheral groove 11 and the outer peripheral groove 21, the pipe is connected (see FIG. 1), and the pipes 10A and 10B can rotate with each other. It is connected in a state where it cannot be pulled or pushed.

The inner peripheral groove 11 is formed by being recessed in the inner peripheral surface 10b of the pipe 10 with the same cross-sectional shape over the entire circumference. The inner peripheral groove 11 has a first inner surface 11a and a second inner surface 11b facing the pipe axis O direction, and a groove bottom surface 11c located on the groove bottom side.

As shown in FIG. 1, the inner peripheral edge portion of the opening located at the pipe end portion 10a of the pipe 10 is gradually directed from the inner peripheral surface 10b to the outer peripheral surface 10c along the pipe axis O toward the pipe end side. 1 Tapered surface 12 is formed. The first tapered surface 12 has a function of reducing the diameter of the C-shaped fitting ring 3 fitted in the outer peripheral groove 21 when the insertion cylinder portion 2A of the cylindrical joint 2 is inserted into the pipe 10. There is.

The cylindrical joint 2 has an insertion cylinder portion 2A on both sides of the central convex portion 22 in the tube axis O direction. One pipe 10A is externally fitted to one insertion tube 2A (here, the left side of the paper), and the other pipe 10B is externally fitted to the other insertion tube 2A (here, the right side of the paper). It is connected in the state of being connected. The central convex portion 22 of the cylindrical joint 2 projects radially outward from the outer peripheral surface 2a and extends in the circumferential direction. The outer peripheral surface 22a of the central convex portion 22 is flush with the outer peripheral surface 10c of the pipe 10 outerly fitted to the insertion cylinder portion 2A.

Between the insertion cylinder portion 2A and the central convex portion 22 of the cylindrical joint 2, a second tapered surface 23 whose diameter is gradually expanded from the insertion cylinder portion 2A toward the central convex portion 22 along the tube axis O is provided. It is formed. In the pipe connected state, the second tapered surface 23 is in a state of being close to or in contact with the first tapered surface 12 of the pipes 10A and 10B connected to each other.

On the outer peripheral surface 2a of the insertion cylinder portion 2A, an outer peripheral groove 21 having a rectangular cross section extending over the entire circumference is formed. A C-shaped fitting ring 3 is fitted to the outer peripheral groove 21 with the inner peripheral groove 11. Then, when the C-shaped fitting ring 3 is fitted between the outer peripheral groove 21 and the inner peripheral groove 11, the pipe connection state T is set, and the pipes 10A and 10B can rotate with each other and cannot be pulled or pushed. It is connected in the state.

As shown in FIG. 3, the outer peripheral groove 21 is formed by being recessed in the outer peripheral surface 2a of the insertion cylinder portion 2A with the same cross-sectional shape over the entire circumference. The outer peripheral groove 21 has a fastening groove portion 24 having a depth dimension Hc of a height dimension Hr or more and a groove width dimension Lc of a width dimension Lr or more of the C-shaped fitting ring 3, and a fastening groove portion 24 in the pipe axis O direction. It has a pulling groove portion 25 in which the depth dimension becomes smaller in the direction of separation (tension direction E1 of the pipe).

The fastening groove portion 24 has a drawing-side inner surface 24a, a bottom surface 24b, and a step portion 24c located at the boundary between the pulling groove portion 25 and the pulling groove portion 25.
The tension groove portion 25 has an inclined bottom surface 25a whose depth becomes shallower from the step portion 24c in the pipe axis O direction toward the pipe tensioning direction E1 and an insertion side located at the end of the pipe tensioning direction E1 of the inclined bottom surface 25a. It has an inner surface 25b and. The inner surface 25b on the insertion side is formed in a tapered shape that is inclined in the tensile direction E1 of the pipe from the inclined bottom surface 25a toward the outer peripheral surface 2a.

Next, FIGS. 3 and 3 show specific configurations of the inner peripheral groove 11 formed in the pipe 10, the outer peripheral groove 21 formed in the insertion cylinder portion 2A of the cylindrical joint 2, and the C-shaped fitting ring 3. It will be described in detail using 6 and the like.

First, as shown in FIG. 3, the lengths Lc and Lt of the two-stage fastening groove portion 24 and the tension groove portion 25 having different depth dimensions in the outer peripheral groove 21 in the pipe axis O direction (see FIG. 1) will be described. ..
In the pipe connecting structure 1, the length dimension of the fastening groove portion 24 (first groove width dimension Lc) and the length dimension of the tension groove portion 25 (second groove width dimension Lt) are the C-shaped fitting ring 3. It is set so as to satisfy the relationship of the equations (1) and (2) with respect to the total width dimension Lr in the pipe axis O direction.

As described above, the first groove width dimension Lc of the fastening groove portion 24 in which the C-shaped fitting ring 3 is located in the pipe connected state by satisfying the equation (1) is equal to or larger than the total width dimension Lr of the C-shaped fitting ring 3. By doing so, it is possible to secure the width dimension in which the C-shaped fitting ring 3 sinks into the fastening groove portion 24.

On the other hand, when a tensile load (arrow F) acts on the pipe 10, the tension groove portion 25 in which the C-shaped fitting ring 3 is located does not necessarily have the second groove width dimension Lt of the C-shaped fitting ring 3. It is not necessary to have the total width dimension Lr or more, but it is necessary to support the C-shaped fitting ring 3 from below so as not to sink.
Therefore, the second groove width dimension Lt of the tension groove portion 25 secures 20% or more of the total width dimension Lr and is set within the range of the equation (2). By setting the second groove width dimension Lt to 20% or more of the total width dimension Lr, the inclination due to the dimensional tolerance of the pipe 10 can be taken into consideration as shown below.

As shown in FIG. 4, depending on the dimensional tolerance of the pipe 10, a gap is inevitably generated between the cylindrical joint 2 forming the joint and the pipe 10, so that the pipe 10 is tilted by an angle θ with respect to the pipe axis O. At this time, enlarged views of the regions X1 and X2 of FIG. 4 are shown in FIGS. 5 (a) and 5 (b), respectively. FIG. 5A, which is an enlarged view of the region X1, shows the inner arc circle side of the bending when the bending is applied downward on the paper surface in FIG. On the other hand, FIG. 5 (b), which is an enlarged view of the region X2, shows the outer arc circle side of the bending when the bending is applied downward on the paper surface in FIG. The state shown in FIG. 6 is obtained on the outer arc circle side of the bend, and the grooves of the pipe 10 and the cylindrical joint 2 (inner peripheral groove 11 and outer peripheral groove 21) are shown on the inner arc circle side of the bend as shown in FIG. 5 (b). Since the deviation Ld is generated at the position of, the initially set second groove width dimension Lt is substantially shortened by the deviation Ld. Here, the reference numeral D shown in FIG. 5B indicates the diameter direction of the pipe 10 (the direction orthogonal to the pipe axis O). In addition, in FIGS. 4 and 5 (a) and 5 (b), in order to make the explanation easy to understand, the inner surface 25b on the insertion side of the pulling groove portion 25 of the outer peripheral groove 21 as shown in FIG. 3 does not have a tapered shape, but a pipe. The surface is in the direction orthogonal to the axis O (diameter direction of the pipe 10).

For example, assuming a pipe 10 having an outer diameter of 114.3 mm and a wall thickness of 6.0 mm of STK400, the wall thickness tolerance of the pipe 10 is -0.5 to +0.6 mm as defined in JIS G344. When the initial gap between the pipe 10 and the cylindrical joint 2 is 0.6 mm, the angle θ = if the overlapping length Lo of the cylindrical joint 2 and the pipe 10 is 114.3 mm, which is about the same as the outer diameter of the pipe. tan ^-1 (0.6 / 114.3) = 0.3 °.

At this time, the deviation Ld of the groove position is 114.3 mm in diameter × tan θ = 0.6 mm due to the geometrical relationship shown in FIG. 5 (b). Assuming that the overall width dimension Lr of the C-shaped fitting ring 3 is 6.0 mm, which is about the same as the steel pipe wall thickness of the pipe 10, the deviation Ld of the groove positions between the inner peripheral groove 11 and the outer peripheral groove 21 is C-shaped fitting. It is about 10% of the total width dimension Lr of the built-in ring 3. In this way, the inclination of the pipe 10 causes a groove shift Ld, which may shorten the effective second groove width dimension Lt. Therefore, it is necessary to secure 20% or more of the total width dimension Lr for the second groove width dimension Lt. There is.

Further, it is more preferable that the second groove width dimension Lt of the tension groove portion 25 is in the range of 0.5Lr ≦ Lt ≦ Lr. In this case, by setting the lower limit value to 0.5 Lr, the center of gravity of the C-shaped fitting ring 3 can be supported from below by the inclined bottom surface 25a of the tension groove portion 25.

As shown in FIG. 6, when the tensile load F acts on the pipe 10, the C-shaped fitting ring 3 moves in the pipe tensile direction E1 (on the left side of the paper in FIG. 6) in the pipe axis O direction and is pulled. It is located in the groove portion 25. The fastening groove portion 24 is set to have a depth dimension Hc equal to or greater than the height dimension Hr of the C-shaped fitting ring 3 in the pipe connected state T. As a result, the C-shaped fitting ring 3 is positioned in the fastening groove portion 24, and the entire thickness (height dimension Hr) of the C-shaped fitting ring 3 sinks into the fastening groove portion 24 to be smoothly fastened.
Further, the depth dimension Ht of the tension groove portion 25 is set to be smaller than the height dimension Hr of the C-shaped fitting ring 3. As a result, the C-shaped fitting ring 3 is prevented from sinking to the tension groove portion 25 side, and the C-shaped fitting ring 3 is counterclockwise (reference numeral P2) in the outer peripheral groove 21 toward the paper surface of FIG. Rotates and deforms in the direction) (see FIG. 7 (d)).

Then, the first groove depth dimension Hp of the inner peripheral groove 11 at the end of the pipe 10, the second groove depth dimension Hc of the fastening groove portion 24 in the outer peripheral groove 21 of the cylindrical joint 2, and the third groove portion 25 for tensioning. The groove depth dimension Ht is set so as to satisfy the relationship of the equations (3) to (5) with respect to the height dimension Hr of the C-shaped fitting ring 3.

In the pipe connection state T, the fastening groove portion 24 in which the C-shaped fitting ring 3 is located needs to have a depth at which the entire C-shaped fitting ring 3 sinks, so that the equation (3) is adopted. Further, due to the geometrical relationship, the total of the first groove depth dimension Hp of the inner peripheral groove 11 of the pipe 10 and the second groove depth dimension Ht of the pulling groove portion 25 in the outer peripheral groove 21 of the cylindrical joint 2 is C-shaped. Since the C-shaped fitting ring 3 cannot exist in the cylindrical joint 2 unless the height dimension of the fitting ring 3 is Hr or more, the equation (4) is obtained.

On the other hand, when the tensile load F is applied, if the C-shaped fitting ring 3 is caught in the inner peripheral groove 11 of the pipe 10 and the outer peripheral groove 21 of the cylindrical joint 2 and is not locked, the tensile load is applied. Since it cannot resist, the depth dimension of the outer peripheral groove 21 is adopted to obtain the above-mentioned equation (5). Unless there is an extreme difference in strength between the cylindrical joint 2 and the pipe 10, the areas where the inner peripheral groove 11 of the pipe 10 and the outer peripheral groove 21 of the cylindrical joint 2 each contact the C-shaped fitting ring 3 are as equal as possible. Since the balance is better, 0.4 Hr ≦ Ht ≦ 0.6 Hr is more preferable.

Here, in the above equations (3) to (5), it is preferable to consider the gap Hb of the tolerance generated between the pipe 10 and the cylindrical joint 2. That is, the equations (3) to (5) are set assuming that the gap Hb is included in any of the first groove depth dimension Hp, the second groove depth dimension Hc, and the third groove depth dimension Ht. Can be done. Alternatively, the formula (3) may be Hc + Hb ≧ Hr, the formula (4) may be Hp + Ht + Hb ≧ Hr, and the formula (5) may be 0.1 Hr ≦ Ht + Hb ≦ 0.9 Hr. The size of the gap Hb is about 0.3 to 1.0 mm in diameter.

Next, the operation of the pipe connecting structure 1 described above will be described in detail with reference to the drawings.
In the pipe connecting structure 1 shown in FIGS. 1 and 3 according to the present embodiment, the C-shaped fitting ring 3 is fitted and set in the outer peripheral groove 21 of the cylindrical joint 2, and then the insertion cylinder of the cylindrical joint 2 is inserted. By inserting the portion 2A inside the pipe end portion 10a (or fitting the pipe 10 externally into the insertion cylinder portion 2A of the cylindrical joint 2), the C-shaped fitting ring 3 is gradually formed along the tapered surface 12. The diameter is reduced so that the diameter is equal to or less than the inner diameter of the inner peripheral surface 10b of the pipe 10, and the entire pipe 10 is pushed into the fastening groove portion 24 of the outer peripheral groove 21. As a result, the cylindrical joint 2 is inserted into the pipe 10 without the C-shaped fitting ring 3 being caught on the inner peripheral surface 10b of the pipe 10.

After that, by further inserting the cylindrical joint 2 into the pipe 10 (or inserting the pipe 10 deeply into the cylindrical joint 2), the C-shaped fitting ring 3 becomes a pipe as shown in FIGS. 1 and 3. The diameter is expanded by elastic force at the position of the inner peripheral groove 11 of 10, and a part of the outer peripheral side of the C-shaped fitting ring 103 is fitted into the inner peripheral groove 11. As a result, the C-shaped fitting ring 3 is in a pipe connected state (see FIG. 1) fitted between the outer peripheral groove 21 and the inner peripheral groove 11, and the pipes 10A and 10B can rotate and pull each other. It is connected in a state where it cannot be pushed.

In the pipe connecting structure 1 according to the present embodiment, as shown in FIGS. 7A and 7B, when a tensile load F acts on the pipe 10, the C-shaped fitting ring 3 has a groove portion 24 for fastening the outer peripheral groove 21. Moves from to the tension groove portion 25. At this time, since the tension groove portion 25 is set to have a smaller depth dimension in the direction away from the fastening groove portion 24 (the tension direction E1 of the pipe), it is located on the inner peripheral side of the C-shaped fitting ring 3. The inclined bottom surface 25a of the tension groove portion 25 is located, and there is no space for moving or deforming inward in the radial direction of the C-shaped fitting ring 3, and the inclined bottom surface 25a is supported. Therefore, the C-shaped fitting ring 3 is suppressed from having a rotational force acting in the direction of sinking into the groove bottom of the fastening groove portion 24 (clockwise direction P2 in FIG. 7 (d)), and FIG. 7 (c). ) And (d), the rotational force acts in the direction of entering the inner peripheral groove 11 (arrow P1 in the figure).

That is, as shown in FIGS. 7 (b) and 7 (c), the C-shaped fitting ring 3 in which the rotational force acts in the direction of the arrow P1 (counterclockwise method on the paper surface of FIG. 7) is the pull-out direction of the pipe 10. Since the movement in the direction (direction of the tensile load F) is restricted, the tensile strength of the pipe connecting structure 1 can be improved. As a result, even if the pipe 10 is lifted to the outside of the C-shaped fitting ring 3, it moves in the direction of coming out along the outer peripheral surface 2a of the cylindrical joint 2 beyond the C-shaped fitting ring 3 and is difficult to be detached. The structure is formed, and it is possible to prevent the pipe 10 and the cylindrical joint 2 from being disconnected from each other.

As described above, in the present embodiment, the C-shaped fitting ring 3 housed in the outer peripheral groove 21 has a space in which the C-shaped fitting ring 3 sinks to the lower part when the pipe 10 and the cylindrical joint 2 are fastened. The secured fastening groove 24 is used, and when a tensile load F acts on the pipe 10, a tension groove 25 that closes the space on the inner peripheral side of the C-shaped fitting ring 3 is used, and two outer grooves 21 are used. It is possible to have a function and effectively use the two functions depending on the situation.
As described above, in the present embodiment, the construction can be easily performed with a simple structure that minimizes the processing of the pipe 10 and the members to be connected.

Further, in the present embodiment, as shown in FIG. 3, the first groove width dimension Lc of the fastening groove portion 24 and the second groove width dimension Lt of the tension groove portion 25 are the total width of the C-shaped fitting ring in the pipe axis direction. It is set so as to satisfy the relationship between the above equations (1) and (2) with respect to the dimension Lr. Therefore, the center of gravity of the C-shaped fitting ring 3 can be supported by the inclined bottom surface 25a of the tension groove portion 25, and the rotational force is applied in the direction in which the C-shaped fitting ring 3 sinks into the groove bottom of the fastening groove portion 24. The action can be suppressed more reliably.

Further, in the present embodiment, the first groove depth dimension Hp at the end of the pipe 10, the second groove depth dimension Hc of the fastening groove portion 24 in the cylindrical joint 2, and the third groove depth dimension of the tension groove portion 25. Ht is set so as to satisfy the relationship of the above-mentioned equations (3) to (5) with respect to the height dimension Hr of the C-shaped fitting ring 3. Therefore, when a tensile load is applied to the pipe 10, the C-shaped fitting ring 3 is easily caught in the inner peripheral groove 11 of the pipe 10 and the outer peripheral groove 21 of the cylindrical joint 2 and is easily locked, and the pipe 10 is pulled. It can resist the load F.

In the pipe connecting structure 1 according to the above-described embodiment, the construction is simple and sufficient tensile strength is ensured while minimizing the processing of the members such as the pipes 10A and 10B to be connected and the cylindrical joint 2. Can be done.

Next, an example carried out to support the effect of the pipe connection structure 1 according to the above-described embodiment will be described below.

(Example)
In the embodiment, in order to confirm the effect of the pipe connection structure 1 described above, an FEA model by the elasto-plastic finite element method (FEA) is created and numerical simulation analysis is performed, and a tensile load F is applied to the pipe 10 of the pipe connection structure 1. The structural analysis of the joint deformation behavior when the above was applied was performed, and the effect was confirmed.

7 (a) to 7 (d) are also cross-sectional views of a main part schematically showing the analysis results of this embodiment. As a result, it was confirmed that the C-shaped fitting ring 3 rotated counterclockwise (in the direction of arrow P2) with respect to the paper surface, and the early disconnection of the pipe 10 and the cylindrical joint was suppressed.

FIG. 8 shows a tensile test in an embodiment in which a fastening groove and a tension groove are provided in the outer peripheral groove as in the above-described embodiment, and a comparative example consisting of a conventional outer peripheral groove in which the tension groove is not provided. , Is a graph showing the relationship between displacement (mm) and load (kN). As a result, it was confirmed that the tensile load of the example was larger than that of the comparative example.

Next, another embodiment of the pipe connecting structure of the present invention will be described with reference to the accompanying drawings, but the description will be omitted by using the same reference numerals for the same or similar members and parts as those of the first embodiment described above. Then, a configuration different from the embodiment will be described.

(Second Embodiment)
The pipe connection structure 1A according to the second embodiment shown in FIG. 9 will be described.
The cylindrical joint 2 has an outer fitting cylinder portion 2B fitted to the outside of the pipe end portion 10a, an inner peripheral groove 26 is formed on the inner peripheral surface 2b of the outer fitting cylinder portion 2B, and the outer periphery of the pipe end portion 10a is formed. An outer peripheral groove 13 is formed on the surface 10c.
In this case, the C-shaped fitting ring 3 is fitted between the inner peripheral groove 26 and the outer peripheral groove 13 in the pipe connected state. The inner peripheral groove 26 includes a fastening groove portion 27 having a depth dimension equal to or larger than the height dimension of the C-shaped fitting ring 3 and a groove width dimension equal to or larger than the width dimension of the C-shaped fitting ring 3. It has a tension groove portion 28 whose depth dimension becomes smaller in the direction away from the fastening groove portion 27 in the axis O direction.

In the pipe connecting structure 1A according to the second embodiment, when a tensile load acts on the pipe 10, the C-shaped fitting ring 3 moves from the fastening groove portion 27 of the inner peripheral groove 26 to the tension groove portion 28. At this time, since the tension groove portion 28 is set to have a smaller depth dimension in the direction away from the fastening groove portion 27, the inclined bottom surface 28a of the tension groove portion 28 is set on the outer peripheral side of the C-shaped fitting ring 3. (Groove bottom) is located, and there is no space for moving or deforming the C-shaped fitting ring 3 to the outside in the radial direction, and the C-shaped fitting ring 3 is supported from the inclined bottom surface 28a.

Therefore, in the C-shaped fitting ring 3, the rotational force is suppressed from acting in the direction of sinking into the groove bottom of the fastening groove portion 27, and the rotational force acts in the direction of entering the outer peripheral groove 13. That is, since the C-shaped fitting ring 3 on which the rotational force acts restricts the movement of the pipe 10 in the pulling direction, the tensile strength of the pipe connecting structure 1A can be improved. As a result, even if the pipe 10 is lowered inside the C-shaped fitting ring 3, it moves beyond the C-shaped fitting ring 3 and moves out along the inner peripheral surface 2b of the cylindrical joint 2 and is detached. The structure is difficult, and it is possible to prevent the pipe 10 and the member of the cylindrical joint 2 from being disconnected from each other.

As described above, in the pipe connecting structure 1A according to the second embodiment, the C-shaped fitting ring housed in the inner peripheral groove 26 has the C-shaped fitting ring 3 when the pipe 10 and the cylindrical joint 2 are fastened. A fastening groove 27 that secures a space to sink in the lower part is used, and when a tensile load is applied to the pipe 10, a tension groove 28 that closes the space on the outer peripheral side of the C-shaped fitting ring 3 is used, and the inner circumference is used. The groove 26 can be provided with two functions so that the two functions can be effectively used depending on the situation.
As described above, in the present embodiment, the construction can be easily performed with a simple structure that minimizes the processing of the pipe 10 and the members to be connected.

Although the embodiment of the pipe connecting structure according to the present invention has been described above, the present invention is not limited to the above-described embodiment and can be appropriately modified without departing from the spirit of the present invention.

For example, the groove shape of the outer peripheral groove 21 of the cylindrical joint 2 is not limited to this embodiment. For example, in the modified example shown in FIG. 10, the tension groove portion 25A of the outer peripheral groove 21A extends in a direction in which the insertion side inner surface 25d extends in a direction orthogonal to the outer peripheral surface 2a of the insertion cylinder portion 2A when viewed from the circumferential direction.

Further, in the present embodiment, the first groove width dimension Lc of the fastening groove portion and the second groove width dimension Lt of the tension groove portion are described above with respect to the total width dimension Lr in the pipe axis direction of the C-shaped fitting ring ( Although it is configured to satisfy the relations of the equations 1) and (2), it is not limited to satisfying such a relational expression.

Further, in the present embodiment, the first groove depth dimension Hp at the end of the pipe, the second groove depth dimension Hc of the fastening groove portion in the cylindrical joint, and the third groove depth dimension Ht of the tension groove portion are C. Although the configuration is such that the above-mentioned relations of the equations (3) to (5) are satisfied with respect to the height dimension Hr of the character-shaped fitting ring, the present invention is not limited to satisfying such relational expressions.

In addition, it is possible to replace the components in the above-described embodiment with well-known components as appropriate without departing from the spirit of the present invention.

1, 1A Pipe connection structure 2 Cylindrical joint 2A Insertion cylinder 2B Outer cylinder 3 C-shaped fitting ring 10, 10A, 10B Pipe 11 Inner peripheral groove 13 Outer groove 21 Outer groove 24 Fastening groove 25, 25A Tension Groove 25a Inclined bottom (groove bottom)
25d Insertion side inner surface 26 Inner peripheral groove 27 Fastening groove 28 Tension groove O Pipe shaft

Claims (4)

It is a pipe connecting structure that connects a pair of the pipes on a coaxial line via a cylindrical joint having an insertion cylinder portion inserted at the end of the pipe at both ends.
On the outer peripheral surface of the insertion cylinder portion, an outer peripheral groove extending over the entire circumference of the outer peripheral surface and
On the inner peripheral surface of the end of the pipe, an inner peripheral groove extending over the entire circumference of the inner peripheral surface and
A C-shaped fitting ring that is fitted into each of the outer peripheral groove and the inner peripheral groove in the circumferential direction to form a pipe connection state is provided.
The outer peripheral groove is
A fastening groove portion having a depth dimension equal to or larger than the height dimension of the C-shaped fitting ring and a groove width dimension equal to or larger than the width dimension of the C-shaped fitting ring.
A pipe connecting structure characterized by having a tension groove portion whose depth dimension becomes smaller in a direction away from the fastening groove portion in the pipe axis direction. It is a pipe connecting structure that connects a pair of the pipes on a coaxial line via a cylindrical joint having an outer fitting cylinder portion at both ends into which the end portion of the pipe is inserted.
On the inner peripheral surface of the outer fitting cylinder portion, an inner peripheral groove extending over the entire circumference of the inner peripheral surface and
On the outer peripheral surface of the end of the pipe, an outer peripheral groove extending over the entire circumference of the outer peripheral surface and
A C-shaped fitting ring that is fitted into each of the inner peripheral groove and the outer peripheral groove in the circumferential direction to form a pipe connection state is provided.
The inner groove is
A fastening groove portion having a depth dimension equal to or larger than the height dimension of the C-shaped fitting ring and a groove width dimension equal to or larger than the width dimension of the C-shaped fitting ring.
A pipe connecting structure characterized by having a tension groove portion whose depth dimension becomes smaller in a direction away from the fastening groove portion in the pipe axis direction. The first groove width dimension Lc of the fastening groove portion and the second groove width dimension Lt of the tension groove portion are the equation (1), (2) with respect to the total width dimension Lr of the C-shaped fitting ring in the pipe axis direction. ) The pipe connection structure according to claim 1 or 2, wherein the relationship of the equation is satisfied.

The first groove depth dimension Hp at the end of the pipe, the second groove depth dimension Hc of the fastening groove portion in the cylindrical joint, and the third groove depth dimension Ht of the tension groove portion are C-shaped. The pipe connecting structure according to claim 1 or 2, wherein the relationship of the equations (3) to (5) is satisfied with respect to the height dimension Hr of the fitting ring.

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