TWI823421B - Mechanical joints, steel pipes with joints, methods of manufacturing steel pipes with joints, structures including mechanical joints, construction methods of structures including mechanical joints, and design methods of mechanical joints - Google Patents

Abstract

An object of the present invention is to reduce the press-fit load required for fitting without causing an increase in processing costs and a decrease in strength. The mechanical joint 1 of the present invention includes an inner joint tube 5 and an outer joint tube 7, and includes a radially flexible dividing piece 11, a convex part 13, an engaging part 17 and a guiding part 19. The dividing pieces 11 are grouped into For a plurality of groups that satisfy the following conditions (1) and (2), the timing at which the maximum deflection is reached is shifted in units of divided pieces 11 of the same group during the fitting process. (1) The axial positions where maximum deflection occurs in the guide portion of the divided pieces belonging to the same group are the same, and the axial positions in each group are different; (2) For the divided pieces belonging to the same group, if When adjacent divided pieces are connected with a straight line at their circumferential centers, a straight line passing through the center of the tube or a polygon whose center of gravity coincides with the center of the tube is formed.

Description

Mechanical joints, jointed steel pipes, jointed steel pipes Manufacturing method, structure including mechanical joints, construction method of structure including mechanical joints, and design method of mechanical joints

The present invention relates to a mechanical joint for joining steel pipes to each other, a jointed steel pipe including a mechanical joint, a manufacturing method of a jointed steel pipe, a mechanical joint, and a plurality of joints including a plurality of joints joined by a mechanical joint. The structure of the steel pipe, the construction method of the structure and the design method of mechanical joints.

In the past, welding was mainly used to join steel pipes to each other. However, in recent years, due to shortened construction periods or quality management problems, mechanical joining has gradually been used. Regarding this mechanical joining, Patent Document 1 discloses a joint that can be joined by just insertion and has excellent workability.

The "joint structure of steel pipes" described in Patent Document 1 is provided with an outer joint pipe and an inner joint pipe at the ends of the steel pipes to be joined, and the outer joint pipe and the inner joint pipe are inserted into each other in the pipe axis direction. Fitting to join the steel pipes. The top end of any one of the outer joint pipe and the inner joint pipe is divided in the circumferential direction and can be flexed in the radial direction. A pressing load is applied in the axial direction, and the tip of either the outer joint pipe or the inner joint pipe is deflected and inserted. At this time, the deflection is restored to the insertion end position, and the convex portion formed on the outer peripheral surface of the inner joint pipe is connected to the formed The engaging portion formed on the inner peripheral surface of the outer joint pipe is engaged and fitted, or the convex portion formed on the inner peripheral surface of the outer joint pipe is engaged and fitted with the engaging portion formed on the outer peripheral surface of the inner joint pipe.

[Prior art documents]

[Patent Document]

Patent Document 1: Japanese Patent Application Publication No. 2004-36329

In the joint described in Patent Document 1, the circumferentially divided portion of the tip has an arc-shaped cross section and therefore has higher bending rigidity than a rectangular cross section, and requires a large press load when fitting the joints together. . In addition, joints generally require the same compression and tensile strength as steel pipes. Therefore, if the thickness of the joint is increased according to the specifications of the steel pipe, a larger press-in load is required. An increase in the press-fit load required for fitting by insertion will deteriorate the workability, so methods to reduce the press-fit load are being studied.

Therefore, in order to reduce the necessary press-fit load, it is considered to increase the number of divisions of the flexural portion. However, when this portion is cut for production, the number of cutting parts increases, which increases the processing cost. Furthermore, as the number of divisions increases, the strength of the portion may decrease, causing irreversible deformation such as torsion due to unexpected loads during transportation or work, and may result in failure to fit during construction. Therefore, a mechanical joint that can reduce the press-fit load without increasing the number of divisions is required.

The present invention has been made in view of the above problems, and an object thereof is to provide a mechanical joint, a steel pipe with a joint, a manufacturing method of a steel pipe with a joint, a structure, and a structure. The construction method of the structure and the design method of the mechanical joint can reduce the press-in load required for fitting without increasing the processing cost and reducing the strength, thereby improving the workability.

A mechanical joint according to one aspect of the present invention includes an inner joint pipe and an outer joint pipe, each of which is provided at an end of a steel pipe to be joined, and any one of the inner joint pipe and the outer joint pipe is included in The segmented pieces are divided into equal intervals in the circumferential direction and can be flexed in the radial direction, and the mechanical joint includes: a convex portion formed on the outer peripheral surface of the inner joint tube; and an engaging portion formed on the outer joint tube. The inner peripheral surface of the inner joint pipe is engaged with the convex part in a state where the inner joint pipe and the outer joint pipe are fitted together, and together with the convex part resists the tensile load; and a guide part is provided on A portion of the outer joint pipe closer to the distal end than the engaging portion abuts the convex portion in the middle of fitting the inner joint pipe and the outer joint pipe, and cooperates with the convex portion. The divided pieces are deflected and maintained in a deflected state until the engaging portion, and the divided pieces are grouped into a plurality of groups that satisfy the following conditions (1) and (2) so that they can be inserted into each other. During the joining process, the timing of reaching the maximum deflection is staggered in units of divided pieces of the same group.

(1) The split pieces belonging to the same group have the same axial position where maximum deflection occurs in the guide portion, and the axial positions in each group are different.

(2) For divided pieces belonging to the same group, if the centers of the adjacent divided pieces in the circumferential direction are connected with a straight line, a straight line passing through the center of the tube or a polygon whose center of gravity coincides with the center of the tube will be formed.

One aspect of the mechanical joint of the present invention includes: an inner joint tube and an outer joint tube. The joint pipes are respectively provided at the ends of the steel pipes to be joined, and each of the inner joint pipe and the outer joint pipe includes divided pieces that are divided at equal intervals in the circumferential direction and are flexible in the radial direction, And the mechanical joint includes: a convex part formed on the inner peripheral surface of the outer joint pipe; an engaging part formed on the outer peripheral surface of the inner joint pipe, between the outer joint pipe and the inner joint pipe. When the fitting is completed, it is engaged with the convex part and resists the tensile load together with the convex part; and a guide part is provided on the top end side of the inner joint pipe than the engaging part, The outer joint pipe comes into contact with the convex part in the middle of fitting the inner joint pipe, cooperates with the convex part to deflect the divided piece, and maintains the deflected state until the to the engaging portion, and the divided pieces are grouped into a plurality of groups that satisfy the following conditions (1) and (2), so that the divided pieces of the same group can be used as a unit to achieve maximum deflection during the fitting process. The timing is staggered.

(1) The split pieces belonging to the same group have the same axial position where maximum deflection occurs in the guide portion, and the axial positions in each group are different.

(2) For divided pieces belonging to the same group, if the centers of the adjacent divided pieces in the circumferential direction are connected with a straight line, a straight line passing through the center of the tube or a polygon whose center of gravity coincides with the center of the tube will be formed.

In one aspect of the mechanical joint of the present invention, the divided pieces of the other group do not start to radially deflect before the divided pieces of one group reach maximum deflection.

A steel pipe with a joint according to one aspect of the present invention includes an inner joint pipe and/or an outer joint pipe in the mechanical joint of the invention at both ends or at one end.

A method of manufacturing a steel pipe with a joint according to one aspect of the present invention is a method of manufacturing the steel pipe with a joint of the invention, and attaching the outer ends of the mechanical joints of the invention to the ends of the steel pipes to be joined. Joint pipe and/or inner joint pipe.

A structure of one aspect of the present invention includes the mechanical joint of the invention and a plurality of steel pipes joined by the mechanical joint.

A construction method of a structure of one aspect of the present invention is a method of constructing the structure of the invention, and a steel pipe with the outer joint pipe installed at the end and a steel pipe with the inner joint pipe installed at the end Any one of the steel pipes of the pipe is installed vertically in the ground, and another steel pipe is placed on one of the steel pipes in this state, so that the inner joint pipe and the outer joint pipe are fitted and joined. .

A method for designing a mechanical joint of one aspect of the present invention designs a mechanical joint. The mechanical joint includes an inner joint pipe and an outer joint pipe, which are respectively provided at the ends of the steel pipes to be joined. The inner joint pipe Any one of the outer joint pipes includes divided pieces that are divided at equal intervals in the circumferential direction and are flexible in the radial direction, and the mechanical joint includes a convex portion formed on the outer periphery of the inner joint pipe. surface; an engaging portion is formed on the inner circumferential surface of the outer joint pipe, and is engaged with the convex portion when the inner joint pipe and the outer joint pipe are mated together, and is together with the convex portion. and resist tensile load; and a guide portion is provided on the top end side of the outer joint pipe than the engaging portion, and is in contact with the inner joint pipe and the outer joint pipe during the fitting process. The convex portion cooperates with the convex portion to deflect the divided piece and maintain the deflected state until the engaging portion, and the In the design method of the mechanical joint, the divided pieces are grouped into a plurality of groups that satisfy the following conditions (1) and (2), and the maximum deflection is achieved in units of divided pieces of the same group during the fitting process. The timing is staggered, and the horizontal stress generated by the deflection of the divided pieces is offset.

(1) The split pieces belonging to the same group have the same axial position where maximum deflection occurs in the guide portion, and the axial positions in each group are different.

(2) For divided pieces belonging to the same group, if the centers of the adjacent divided pieces in the circumferential direction are connected with a straight line, a straight line passing through the center of the tube or a polygon whose center of gravity coincides with the center of the tube will be formed.

A method for designing a mechanical joint of one aspect of the present invention designs a mechanical joint. The mechanical joint includes an inner joint pipe and an outer joint pipe, which are respectively provided at the ends of the steel pipes to be joined. The inner joint pipe Any one of the outer joint pipes includes divided pieces that are divided at equal intervals in the circumferential direction and are flexible in the radial direction, and the mechanical joint includes: a convex portion formed inside the outer joint pipe. circumferential surface; an engaging portion formed on the outer circumferential surface of the inner joint pipe, and is engaged with the convex portion when the outer joint pipe and the inner joint pipe are fitted together, and is connected to the convex portion. and resist tensile load; and a guide portion is provided on the top end side of the inner joint pipe than the engaging portion, and is in contact with the outer joint pipe in the middle of fitting the outer joint pipe and the inner joint pipe. The convex portion cooperates with the convex portion to deflect the split piece and maintain the deflected state until the engaging portion, and in the method of designing the mechanical joint, the The segmented pieces are grouped into multiple groups that meet the following conditions (1) and (2). In the fitting process, the segmented pieces of the same group are regarded as a single group. This position staggers the timing of reaching maximum deflection and offsets the stress in the horizontal direction caused by the deflection of the divided pieces.

(1) The split pieces belonging to the same group have the same axial position where maximum deflection occurs in the guide portion, and the axial positions in each group are different.

(2) For divided pieces belonging to the same group, if the centers of the adjacent divided pieces in the circumferential direction are connected with a straight line, a straight line passing through the center of the tube or a polygon whose center of gravity coincides with the center of the tube will be formed.

According to the present invention, the divided pieces are grouped into multiple groups in a manner that satisfies predetermined conditions. During the fitting process, the timing of reaching the maximum deflection is staggered based on the divided pieces of the same group, thereby reducing the pressure required for fitting. load, the construction performance is improved. Furthermore, according to the present invention, the pressing load can be reduced without increasing the number of divided pieces, so the processing cost does not increase or the strength does not decrease.

1, 2, 23: Mechanical joint

3:Steel pipe

5. 5A: Inner joint pipe

7, 7A, 25: Outer joint pipe

9. 9A: Base end

11, 11A, A ₁ ~A ₄ , B ₁ ~B ₄ , C ₁ ~C ₃ : divided slices

13, 13A: convex part

13a, 19a: tilted face

15, 15A: concave part

17, 17A: Engagement part

19, 19A: Guidance Department

19b:Flat face

21: Center of tube

X ₀ ~X ₃ : Axial position

1A is a diagram showing a mechanical joint according to an embodiment of the present invention, and is a diagram schematically showing the deflection of the divided pieces during the joining process.

1B is a diagram showing a mechanical joint according to an embodiment of the present invention, and is a diagram schematically showing the deflection of the divided pieces during the joining process.

1C is a diagram showing a mechanical joint according to an embodiment of the present invention, and is a diagram schematically showing the deflection of the divided pieces during the joining process.

1D is a diagram showing a mechanical joint according to an embodiment of the present invention. A diagram schematically showing the deflection of the divided pieces during the joining process.

FIG. 2 is a diagram showing an example of grouping eight divided slices in a manner that satisfies the conditions of the present invention.

FIG. 3A is a diagram for explaining the press-in load when a conventional mechanical joint is used as a comparative example.

FIG. 3B is a diagram for explaining the press-in load when a conventional mechanical joint is used as a comparative example.

FIG. 3C is a diagram for explaining the press-in load when a conventional mechanical joint is used as a comparative example.

FIG. 4A is a diagram for explaining the press-in load of the mechanical joint according to the embodiment of the present invention.

FIG. 4B is a diagram for explaining the press-in load of the mechanical joint according to the embodiment of the present invention.

FIG. 4C is a diagram for explaining the press-in load of the mechanical joint according to the embodiment of the present invention.

FIG. 5 is a diagram showing an example of grouping four divided slices in a manner that satisfies the conditions of the present invention.

FIG. 6 is a diagram showing an example in which eight divided slices are grouped in a manner that does not satisfy the conditions of the present invention.

FIG. 7 is a schematic diagram showing a state before fitting of the mechanical joint according to the modification of the embodiment of the present invention.

FIG. 8 is a diagram showing the insertion of a mechanical joint according to a modified example of the embodiment of the present invention. Schematic diagram of the combined state.

FIG. 9A is a diagram illustrating the joining process of another aspect of the mechanical joint.

FIG. 9B is a diagram illustrating the joining process of another aspect of the mechanical joint.

FIG. 9C is a diagram illustrating the joining process of another aspect of the mechanical joint.

FIG. 9D is a diagram illustrating the joining process of another aspect of the mechanical joint.

FIG. 10A is a diagram showing another aspect of the mechanical joint of FIG. 1A , and is a diagram schematically showing the deflection of the split piece during the joining process.

FIG. 10B is a diagram showing another aspect of the mechanical joint of FIG. 1B , and is a diagram schematically showing the deflection of the divided pieces during the joining process.

FIG. 10C is a diagram showing another aspect of the mechanical joint of FIG. 1C , and is a diagram schematically showing the deflection of the divided pieces during the joining process.

FIG. 10D is a diagram showing another aspect of the mechanical joint of FIG. 1D , and is a diagram schematically showing the deflection of the split piece during the joining process.

FIG. 11 is a schematic diagram showing a conventional mechanical joint, showing a state before fitting.

FIG. 12 is a diagram showing the mechanical joint of FIG. 11 in a mated state.

Figure 13 is a view of arrow A-A in Figure 11 .

FIG. 14A is a diagram illustrating the joining process of the previous mechanical joint.

FIG. 14B is a diagram illustrating the joining process of the previous mechanical joint.

FIG. 14C is a diagram illustrating the joining process of the previous mechanical joint.

FIG. 14D is a diagram illustrating the joining process of the previous mechanical joint.

Figure 15 shows a divided piece during the joining process shown in Figures 14A to 14D Graph showing the relationship between axial displacement and load.

Before describing the mechanical joint according to one embodiment of the present invention, the structure of the previous mechanical joint will be described based on FIGS. 11 , 12 , 13 , 14A, 14B, 14C and 14D.

As shown in FIG. 11 , an example of the conventional mechanical joint 23 includes an inner joint pipe 5 and an outer joint pipe 25 , which are respectively provided at the ends of the steel pipes 3 to be joined. The inner joint pipe 5 and the outer joint pipe 25 are arranged to face each other up and down. In the state of FIG. 11 , an axial load is applied to the inner joint pipe 5 disposed above, and the inner joint pipe 5 is inserted into the outer joint pipe 25 , so that the inner joint pipe 5 and the outer joint pipe 25 are fitted, as shown in FIG. 12 The upper and lower steel pipes 3 are joined as shown.

The inner joint pipe 5 has a base end 9 welded to the steel pipe 3. On the top side of the base end 9, a cylindrical member with an outer diameter smaller than that of the base end 9 is provided to form a narrow slot extending in the axial direction. The divided piece 11 is divided by sewing. FIG. 13 is a view of arrow A-A in FIG. 11 , and only the top end of the divided piece 11 is shown. As shown in FIGS. 11 and 13 , in the mechanical joint 23 , the top end of the inner joint pipe 5 is divided into eight, for example, and eight divided pieces 11 with arcuate cross-sections are arranged at equal intervals in the circumferential direction. The dividing piece 11 is flexible in the radial direction, and a convex portion 13 protruding outward is formed on the outer peripheral surface of the top end portion.

The inner diameter of the outer joint pipe 25 is smaller than the outer diameter of the portion of the inner joint pipe 5 where the convex portion 13 is formed, and a recessed portion 15 is formed on the base end side of the inner peripheral surface of the outer joint pipe 25 . While the inner joint pipe 5 is inserted into the outer joint pipe 25 and fitted, the inner peripheral surface of the outer joint pipe 25 comes into pressing contact with the convex portion 13 of the inner joint pipe 5, thereby The divided piece 11 of the inner joint pipe 5 is deflected radially inward. When the insertion is completed, the deflection of the split piece 11 is restored, and the convex portion 13 of the inner joint pipe 5 enters the recessed portion 15 of the outer joint pipe 25 to complete the fitting.

The joining process of the inner joint pipe 5 and the outer joint pipe 25 will be described in more detail based on FIGS. 14A, 14B, 14C and 14D. 14A to 14D schematically show an axial cross-section of part B in FIG. 11 . As shown in FIG. 14A , an engaging portion 17 and a guide portion 19 are provided on the inner peripheral surface of the outer joint pipe 25 . The engaging portion 17 constitutes the side wall of the recessed portion 15 and is engaged with the convex portion 13 of the inner joint pipe 5 . The guide portion 19 cooperates with the convex portion 13 to deflect the divided piece 11 while the inner joint pipe 5 is being inserted into the outer joint pipe 25 and the guide portion 19 maintains the deflected state until the engaging portion 17 . The guide portion 19 has an inclined surface portion 19 a that starts deflection of the divided piece 11 and guides it until the maximum deflection, and a flat portion 19 b that maintains the maximum deflection until the engaging portion 17 . Furthermore, an inclined surface portion 13 a having a shape corresponding to the inclined surface portion 19 a of the guide portion 19 is formed on the outer peripheral side of the front end of the convex portion 13 of the inner joint pipe 5 .

FIG. 14A shows a state before the inner joint pipe 5 and the outer joint pipe 25 are brought into press contact, that is, before the divided piece 11 starts to deflect. Furthermore, let the axial position of the convex portion 13 at this time be X ₀ . When the split piece 11 moves downward by applying an axial load to the inner joint pipe 5, as shown in FIG. The inclined surface portion 19a of 19 contacts, thereby squeezing the convex portion 13, and causing the divided piece 11 to deflect in the radially inner direction. By providing the guide portion 19 and the convex portion 13 with correspondingly shaped inclined surface portions 19a and 13a, respectively, the force in the pipe axial direction can be converted into a force in the radial direction, and fitting by insertion can be smoothly performed. . 14B shows a state when the outer peripheral surface of the convex portion 13 reaches the apex of the inclined surface portion 19a, that is, when the divided piece 11 is most deflected. Furthermore, let the axial position of the convex portion 13 at this time be X ₁ .

Then, as shown in FIG. 14C , the divided piece 11 is inserted while maintaining the maximum deflection state. Let the axial position of the convex portion 13 shown in FIG. 14C here be X ₂ . When the top end portion of the outer joint pipe 25 comes into contact with the base end portion 9 of the inner joint pipe 5, as shown in FIG. 14D, the deflection of the divided piece 11 is restored, and the convex portion 13 engages and fits with the engaging portion 17. Joining is complete. Let the axial position of the convex portion 13 at this time be X ₃ .

In the mechanical joint 23 that is joined as described above, in response to the axial compressive load acting on the inner joint pipe 5 and the outer joint pipe 25, the base end 9 of the inner joint pipe 5 and the top end of the outer joint pipe 25 are engage in confrontation. Furthermore, in the mechanical joint 23, the convex portion 13 of the inner joint pipe 5 and the engaging portion 17 of the outer joint pipe 25 resist the axial tensile load acting on the inner joint pipe 5 and the outer joint pipe 25.

During the joining process, the load required to insert the inner joint pipe 5 varies depending on the deflection state of the divided piece 11 . This aspect will be explained using FIG. 15 . FIG. 15 is a graph showing the relationship between axial displacement and the magnitude of the load required to bend and insert one divided piece 11 .

As shown in FIG. 15 , the inclined surface portion 19 a of the guide portion 19 comes into contact with the inclined surface portion 13 a of the convex portion 13 , and the divided piece 11 is inserted into the fitting process (X ₀ to X ₁ ) while being bent. , insertion requires a large load. Especially when the divided piece 11 reaches the maximum deflection (X ₁ ), the maximum load is required. On the other hand, the flat surface 19b of the guide part 19 or the inner peripheral surface of the engaging part 17 is in contact with the outer peripheral surface of the convex part 13, and the insertion and fitting process is performed while maintaining maximum deflection (X ₁ ~ In X ₃ ), it is sufficient to have a load exceeding the frictional resistance between the inner joint pipe 5 and the outer joint pipe 25, so fitting can be performed with a small load.

FIG. 15 is a graph showing the load required for inserting and fitting one divided piece 11 while bending it. The load shown in FIG. 15 is also required for each of the other seven divided pieces 11 . That is, in the case of the mechanical joint 23 shown in FIGS. 11 to 13 , the eight divided pieces 11 are deflected in unison, so the load required to insert and fit the inner joint pipe 5 is approximately the load shown in FIG. 15 8 times.

As mentioned above, in the conventional mechanical joint 23, all the divided pieces 11 are uniformly bent and inserted. Therefore, when the eight divided pieces 11 reach the maximum deflection (X1) at the same time, a particularly large load is required. From this viewpoint, the present inventors devised a method of staggering the timing at which each divided piece 11 reaches its maximum deflection. Thereby, the maximum load required to insert the mechanical joint 23 as a whole can be reduced.

In addition, when the steel pipes 3 are joined using the mechanical joint 23, either the steel pipe 3 to which the outer joint pipe 25 is attached and the steel pipe 3 to which the inner joint pipe 5 is attached are placed vertically in the ground. The other one is hoisted by a crane, placed above the steel pipe 3 erected in the ground, and inserted. At this time, it is difficult to restrict the horizontal movement of the upper steel pipe 3 lifted by the crane, so it is preferable to completely offset the horizontal stress generated when the split piece 11 deflects during the joining process. In this regard, in the conventional mechanical joint 23, a polygon (a two-point chain line in FIG. 13) connecting the centers of the arcs of the divided pieces 11 (an x mark in FIG. 13) is used. The center of gravity is consistent with the center 21 of the tube. Thereby, the stress in the horizontal direction caused by the deflection of the divided piece 11 is offset. The offset of the stress in the horizontal direction during insertion should also be considered when the timing of the split piece 11 reaching the maximum deflection is shifted as described above. The present invention is based on this finding. In one embodiment described below, a case where the inner joint pipe is divided into eight parts will be described as an example. In the following description, the same parts as those in FIGS. 11 to 14A to 14D showing the previous example are denoted by the same reference numerals.

The mechanical joint 1 according to one embodiment of the present invention includes an inner joint pipe 5 and an outer joint pipe 7, which are respectively provided at the ends of the steel pipes 3 to be joined. The inner joint pipe 5 includes divided pieces 11 that are divided into eight pieces at equal intervals in the circumferential direction and are flexible in the radial direction. A convex portion 13 is formed on the outer peripheral surface of the divided piece 11 . An engaging portion 17 is provided on the inner peripheral surface of the outer joint pipe 7. The engaging portion 17 is engaged with the convex portion 13 when the inner joint pipe 5 and the outer joint pipe 7 are fitted together. Together with the convex portion 13, and resist tensile loads. A guide portion 19 is provided on the front end side of the outer joint pipe 7 relative to the engaging portion 17. The guide portion 19 abuts the convex portion 13 during the fitting of the inner joint pipe 5 and the outer joint pipe 7. The divided piece 11 is deflected in cooperation with the convex portion 13 , and the deflected state is maintained until the engaging portion 17 . The guide portion 19 has an inclined surface portion 19 a that starts deflection of the divided piece 11 and guides it to the maximum deflection, and a flat portion 19 b that maintains the maximum deflection until the engaging portion 17 . Furthermore, an inclined surface portion 13 a having a shape corresponding to the inclined surface portion 19 a of the guide portion 19 is formed on the outer peripheral side of the front end of the convex portion 13 of the inner joint pipe 5 . These structures are the same as those of the previous mechanical joint 23 described in FIGS. 11 to 14D, and therefore their description is omitted. In the following, the characteristic parts of this embodiment will be described in detail. bright.

The inner joint pipe 5 of this embodiment has the same shape as the previous example except for the divided piece 11 . The eight divided pieces 11 of this embodiment are divided into a plurality of groups that satisfy the following conditions (1) and (2). The eight divided pieces 11 are configured so that the timing of reaching the maximum deflection is staggered in units of divided pieces of the same group during the fitting process.

<condition>

(1) The split pieces belonging to the same group have the same axial position where maximum deflection occurs in the guide portion, and the axial positions in each group are different.

The condition (1) is used to stagger the timing (period) at which the maximum deflection is reached in units of divided pieces of the same group during the fitting process.

(2) For divided pieces belonging to the same group, if the centers of the adjacent divided pieces in the circumferential direction are connected with a straight line, a straight line passing through the center of the tube or a polygon whose center of gravity coincides with the center of the tube will be formed.

The condition (2) is a condition for completely canceling out the stress in the horizontal direction caused by the deflection of the split piece 11 during the fitting process of the mechanical joint.

As a prerequisite for satisfying these conditions (1) and (2), the number of divisions must be 4 or more. When the number of divisions is 3 or less, one division piece may belong to one group. In this case, the straight line or polygon of condition (2) cannot be formed.

In this embodiment, the eight divided pieces 11 of the inner joint pipe 5 are divided into two groups, A ₁ to A ₄ and B ₁ to B ₄ , as shown in FIG. 2 . According to the condition (1), the axial position of the inclined surface portion 19a that deflects the divided pieces 11 of each group is different in each group. FIG. 1A is a cross-sectional view of the divided pieces 11 of A ₁ to A ₄ and the guide portion 19 of the portion in contact with the divided pieces 11 of A ₁ to A ₄ . FIG. 1B is a cross-sectional view of the divided pieces 11 of B ₁ to B ₄ and the guide portion 19 of the portion in contact with the divided pieces 11 of B ₁ to B ₄ . 1A and 1B show an initial state in which the inner joint pipe 5 is inserted into the outer joint pipe 7 .

As shown in FIG. 1A, the inclined surface portion 19a in contact with the divided pieces 11 of _{A1 to A4} is formed between _{X0 and} . Furthermore, as shown in FIG. 1B , the inclined surface portion 19 a in contact with the divided pieces 11 of B ₁ to B ₄ is formed between X _{1 to x2} .

Thereby, in the initial stage of insertion shown in FIGS. 1A and 1B , the divided pieces 11 of A ₁ to A ₄ are in a state of being deflected while abutting against the inclined surface portion 19 a. In contrast, the divided pieces 11 of B ₁ to B are in a state of being deflected. The divided piece 11 of ₄ does not contact the inclined surface portion 19a and does not deflect.

Next, the state in which the inner coupling pipe 5 is further inserted from the position of FIGS. 1A and 1B is shown in FIGS. 1C and 1D respectively. As shown in FIGS. 1C and 1D , when the divided pieces 11 of A ₁ to A ₄ are in contact with the flat surface 19 b and maintain the maximum deflection state, the divided pieces 11 of B ₁ to B ₄ are in contact with the inclined surface. 19a and the state of deflection.

In this way, in this embodiment, the axial position at which each divided piece 11 reaches maximum deflection is the same position in the same group, but is different in each group. In other words, during the fitting process, the timing at which the divided pieces 11 of the same group reach the maximum deflection are staggered.

Furthermore, in this embodiment, as shown in FIG. 2 , among the divided pieces 11 of the same group, if the centers of the adjacent divided pieces in the circumferential direction are connected with each other by a straight line, a quadrilateral whose center of gravity coincides with the center 21 of the pipe will be formed. (In Figure 2, two-point chain line) (Condition (2)). In addition, in FIG. 2 , the group of the divided pieces 11 of A ₁ to A ₄ is represented by an × mark, and the group of the divided pieces 11 of B ₁ to B ₄ is represented by a □ mark. Furthermore, the "center in the circumferential direction" is assumed to be the same position in the axial direction in each divided piece 11 . When the divided pieces 11 of A ₁ to A ₄ are deflected, the horizontal stresses are offset by the divided pieces 11 of A ₁ and A ₃ and the divided pieces 11 of A ₂ and A ₄ arranged at mutually facing positions. , so there is no overall horizontal stress. Similarly, when the divided pieces 11 of B ₁ to B ₄ are deflected, the divided pieces 11 of B ₁ and B ₃ and the divided pieces 11 of B ₂ and B ₄ are arranged at opposite positions in the horizontal direction. The stress is offset, so there is no overall horizontal stress.

Next, the load reduction effect of the mechanical joint 1 of this embodiment configured as above will be described below. First, as a comparative example, a case will be described in which the inner joint pipe 5 divided into eight parts as shown in FIG. 2 is inserted and fitted into the previous outer joint pipe 25 (see FIGS. 14A to 14D ). As mentioned above, in the previous outer joint pipe 25, all the inclined surface portions 19a in contact with the eight divided pieces 11 are formed at the same position in the axial direction (positions X ₀ to X ₁ shown in FIGS. 14A to 14D). The relationship between the axial displacement and the load required for insertion when the outer joint pipe 25 is inserted into and fitted into the inner joint pipe 5 as described above is shown in FIGS. 3A , 3B and 3C respectively.

FIG. 3A shows the load required to deflect the four divided pieces 11 corresponding to the positions A ₁ to A ₄ shown in FIG. 2 in the conventional outer joint pipe 25 and the timing sequence in which the deflection occurs. As shown in FIG. 3A , when the divided pieces 11 of A ₁ to A ₄ reach the maximum deflection (X ₁ ), the maximum load is required. FIG. 3B shows the load required to deflect the four divided pieces 11 corresponding to the positions B ₁ to B ₄ shown in FIG. 2 in the previous outer joint pipe 25 and the timing sequence in which the deflection occurs. As shown in FIG. 3B , the divided pieces 11 of B ₁ to B ₄ also reach the maximum deflection at the same timing (X ₁ ) as the divided pieces 11 of A ₁ to A ₄ , and the maximum load is required at this time.

Figure 3C is a composite of Figure 3A and Figure 3B. FIG. 3C shows the load required to deflect the eight divided pieces 11 when the inner joint pipe 5 is inserted into and fitted into the outer joint pipe 25 and its timing. As shown in FIG. 3C , when all the eight segmented pieces 11 A ₁ to A ₄ and B ₁ to B ₄ reach the maximum deflection (X ₁ ), the necessary load reaches the maximum value. The maximum value of the necessary load is the sum of the maximum value of the load in FIG. 3A and the maximum value of the load in FIG. 3B.

Next, the case where the inner joint pipe 5 shown in FIG. 2 is inserted into and fitted with the outer joint pipe 7 of this embodiment will be described. In the outer joint pipe 7 of this embodiment, the inclined surface portions 19a in contact with the four divided pieces 11 of _A1 to _A4 are respectively formed at the positions of X0 to _X1 shown in FIGS. _1A to 1D. Furthermore, in the outer joint pipe 7, the inclined surface portions 19a with which the four divided pieces 11 of _B1 to _B4 come into contact are respectively formed at the positions of X1 to _X2 shown in FIGS. _1A to 1D. 4A , 4B and 4C respectively show the relationship between the axial displacement and the load required for insertion when the outer joint pipe 7 of the present embodiment is inserted into the inner joint pipe 5 and fitted.

FIG. 4A shows the load required to deflect the four divided pieces 11 A ₁ to A ₄ and the timing of occurrence of deflection. As shown in FIG. 4A , the load required to deflect the four divided pieces 11 reaches the maximum when the divided pieces 11 of A ₁ to A ₄ reach the maximum deflection (X ₁ ). FIG. 4B shows the load required to deflect the four divided pieces 11 B ₁ to B ₄ and the timing of occurrence of deflection. As shown in FIG. 4B , the load required to deflect the four divided pieces 11 reaches the maximum when the divided pieces 11 of B ₁ to B ₄ reach the maximum deflection (X ₂ ).

Figure 4C is a composite of Figure 4A and Figure 4B. FIG. 4C shows the load and timing required to deflect the eight divided pieces 11 when the inner joint pipe 5 is inserted into the outer joint pipe 7 . As shown in FIG. 4C , by staggering the timing of reaching the maximum deflection by using the same group of divided pieces 11 of A ₁ to A ₄ and B ₁ to B ₄ as a unit, the timing that requires a large load is dispersed to two places. . It can be seen that the maximum value of the load required to insert the mechanical joint 1 is approximately half compared to that in FIG. 3C .

Furthermore, the above example is an example in which the eight divided pieces 11 are divided into two groups, and the timing of reaching the maximum deflection is staggered between the two groups. However, for example, if two facing divided pieces 11 By staggering the timing of reaching maximum deflection in units, the maximum load can be further reduced. That is, four groups of A ₁ and A ₃ , A ₂ and A ₄ , B ₁ and B ₃ , and B ₂ and B ₄ shown in FIG. 2 are set. Furthermore, the positions of the inclined surface portions 19a of the outer joint pipe 7 are made different in the axial direction so that the timing at which the maximum deflection is reached among the four groups is shifted. This enables insertion with approximately 1/4 of the load compared to FIG. 3C .

In this way, even if the number of divided pieces 11 is the same, the load reduction effect changes depending on the number of groups. In terms of construction, it is ideal that the steel pipe 3 placed above can be inserted and fitted using only its own weight. Therefore, it is preferable to set the load in consideration of the number of divisions, the thickness of the division pieces 11, the weight of the steel pipe 3, etc. Lower the target and decide the group Count.

Furthermore, in the above example, the top end of the inner joint pipe 5 is divided into eight parts, but the number of divisions is not limited to this. For example, it is generally desirable to set the number of divisions to 4 or more for small steel pipes with a diameter of 400 mm or less, and to 8 or more for steel pipes with a diameter of more than 400 mm. Therefore, an example in which the top end of the inner joint pipe 5 is divided into four as the minimum number of divisions is shown in FIG. 5 . When the number of divided pieces 11 is four, as shown in FIG. 5 , the opposite groups A ₁ and A ₂ , and B ₁ and B ₂ can be set into the same group. In the example of FIG. 5 , the straight line connecting the circumferential centers of the divided pieces 11 of the same group (a two-point chain line in FIG. 5 ) also passes through the center 21 of the tube, so the condition (2) of the present invention is satisfied.

Furthermore, as long as the condition (2) of the present invention is satisfied, the number of divided pieces 11 is not limited to a multiple of 2, but may also be a multiple of 3. For example, the top end of the inner joint pipe 5 may be divided into nine parts, and three figures connecting the centers of the divided pieces 11 in the circumferential direction with straight lines may be set to form a group like an equilateral triangle. In this case, the centers of gravity of the three equilateral triangles are also consistent with the center 21 of the tube, so the invention is within the scope of application (not shown).

Furthermore, as mentioned above, the condition (2) of the present invention is that when the inner joint pipe 5 is inserted and fitted into the outer joint pipe 7, the stress in the horizontal direction caused by the deflection of the divided piece 11 is caused by A condition under which the stresses in the horizontal direction of the other split pieces 11 that are deflected at the same timing are offset. When each group satisfies the condition (2) of the present invention, the stress in the horizontal direction is offset within the group and the workability during construction is not deteriorated.

In contrast, an example in which condition (2) is not satisfied is shown in FIG. 6 . Figure 6 divides the eight segmented slices 11 into three groups: A ₁ to A ₂ , B ₁ to B ₃ , and C ₁ to C ₃ . In the example shown in FIG. 6 , the straight line connecting the circumferential centers (refer to × marks in FIG. ₆ ) of the divided pieces 11 of A ₁ to A 2 does not pass through the center 21 of the tube. Therefore, only the centers of A ₁ to A ₂ are connected. When the divided piece 11 is deflected, the stresses in the horizontal direction are not offset by each other. Similarly, the triangles connecting the centers of the divided pieces 11 of B ₁ to B ₃ (refer to the □ mark in FIG. 6 ) and the circumferential centers of the divided pieces 11 of C ₁ to C ₃ (refer to the Δ mark in FIG. 6 ) are respectively formed. The center of gravity is also not consistent with the center 21 of the tube, so the stress in the horizontal direction is not offset in the same group. In the above example, although the load required for insertion and fitting is reduced during construction, the upper steel pipe 3 hoisted by a crane or the like moves in the horizontal direction, which deteriorates the workability, so it is not preferable.

As described above, according to the mechanical joint 1 of the present embodiment, all the divided pieces 11 are grouped into a plurality of groups, and the positions where the divided pieces 11 come into contact and generate maximum deflection are different in each group, so that during the fitting process The timing at which the divided pieces 11 of the same group reach maximum deflection are staggered, so the press-fitting load required for fitting can be reduced and the workability can be improved. Furthermore, the pressing load can be reduced without increasing the number of divided pieces 11, so the processing cost does not increase and the strength does not decrease.

Furthermore, the embodiment is configured in such a manner that the divided pieces 11 of the other group do not start to deflect in the radial direction before the divided pieces 11 of one group reach the maximum deflection, but the present invention is not limited thereto. As mentioned above, the maximum load is required when the divided piece 11 reaches the maximum deflection. Therefore, as long as there is at least a time difference in the timing of reaching the maximum deflection, the effects of the present invention can be obtained. Therefore, what is necessary is just to form it so that at least the position of the top of the inclined surface part 19a may differ in each group in the axial direction.

(First modification)

Furthermore, the above-mentioned embodiment shows an example in which the side where the inside is inserted (the inside joint pipe) is divided. However, the present invention is not limited to this. As a first modification of the mechanical joint, the side disposed on the outside may also be used. (Outer joint pipe) divided structure. In this case, radially flexible segmented pieces are formed on the outer joint pipe at equal intervals in the circumferential direction, and guide portions are formed on the inner peripheral surfaces of the segmented pieces. Furthermore, in the inner joint pipe, a convex portion is formed on the outer peripheral surface of a cylindrical member provided on the distal side of the base end portion and having a smaller diameter than the base end portion. In this case, it is only necessary to group the divided pieces into a plurality of groups that satisfy the following conditions (1) and (2), and to allow the maximum deflection of the guide portion formed on the inner peripheral surface of the divided pieces to occur. If the axial position is different in each group, the timing of reaching the maximum deflection can be staggered in the fitting process in units of divided pieces of the same group, and the same effect as the above-described embodiment can be obtained.

(1) The split pieces belonging to the same group have the same axial position where maximum deflection occurs in the guide portion, and the axial positions in each group are different.

(2) For divided pieces belonging to the same group, if the centers of the adjacent divided pieces in the circumferential direction are connected with a straight line, a straight line passing through the center of the tube or a polygon whose center of gravity coincides with the center of the tube will be formed.

(Second modification)

Hereinafter, a second modification of the mechanical joint will be described based on FIGS. 7 , 8 , 9A, 9B, 9C, and 9D. As shown in FIG. 7 , the mechanical joint 2 according to the second modified example includes an inner joint pipe 5A and an outer joint pipe 7A, which are respectively provided at the ends of the steel pipes 3 to be joined. The inner joint pipe 5A and the outer joint pipe 7A are arranged to face each other up and down. In the state shown in Figure 7, connect the outer joint arranged above The pipe 7A applies an axial load, so that the outer joint pipe 7A is externally embedded in the inner joint pipe 5A. Thereby, as shown in FIG. 8 , the outer joint pipe 7A and the inner joint pipe 5A are fitted to join the upper and lower steel pipes 3 .

The outer joint pipe 7A has a base end portion 9A welded to the steel pipe 3, and a divided piece 11A divided into a cylindrical member with a slit extending in the axial direction is provided on the distal end side of the base end portion 9A. In the mechanical joint 2 shown in FIG. 7 , the top end of the outer joint pipe 7A is divided into eight, for example, and eight divided pieces 11A having an arcuate cross-section are arranged at equal intervals in the circumferential direction. The divided piece 11A is flexible in the radial direction, and a convex portion 13A protruding inward is formed on the inner peripheral surface of the top end portion.

The outer diameter of the inner joint pipe 5A is larger than the inner diameter of the portion of the outer joint pipe 7A where the convex portion 13A is formed, and a recessed portion 15A is formed on the proximal end side of the outer peripheral surface of the inner joint pipe 5A. In the middle of fitting the outer joint pipe 7A and the inner joint pipe 5A, the outer peripheral surface of the inner joint pipe 5A comes into pressing contact with the convex portion 13 of the outer joint pipe 7A, so that the divided piece 11A of the outer joint pipe 7A moves radially outward. Flex. In the insertion-completed state, the deflection of the split piece 11A is restored, and the convex portion 13A of the outer joint pipe 7A enters the recessed portion 15A of the inner joint pipe 5A, and the fitting is completed.

Each divided piece 11A in the second modified example is divided into a plurality of groups that satisfy the condition (1) and the condition (2), as in the first embodiment. The eight divided pieces 11A are configured so that the timing of reaching the maximum deflection of the divided pieces of the same group is staggered during the fitting process. In the second modification, also as a prerequisite for satisfying conditions (1) and (2), the number of divisions is 4 or more. Furthermore, the method of dividing each divided piece 11A into a plurality of groups is also the same as in the first embodiment.

That is, in the second modification, the eight divided pieces 11A of the inner joint pipe 5A are divided into two groups, A ₁ to A ₄ and B ₁ to B ₄ , as in FIG. 2 . According to the condition (1), the axial position of the inclined surface portion 19a that deflects the divided pieces 11A of each group is different in each group. 9A is a cross-sectional view of the divided pieces 11A of A ₁ to A ₄ and the guide portion 19A of the portion in contact with the divided pieces 11A of A ₁ to A ₄ . An engaging portion 17A is provided on the outer peripheral surface of the inner joint pipe 5A. The engaging portion 17A is engaged with the convex portion 13A and together with the convex portion 13A when the outer joint pipe 7A and the inner joint pipe 5A are completely fitted. Against tensile loads. 9B is a cross-sectional view of the divided pieces 11A of B ₁ to B ₄ and the guide portion 19A of the portion in contact with the divided pieces 11A of B ₁ to B ₄ . 9A and 9B show an initial state in which the outer joint pipe 7A is fitted into the inner joint pipe 5A. FIG. 9A and FIG. 9B are diagrams corresponding to FIG. 1A and FIG. 1B respectively.

As shown in FIG _. 9A, the inclined surface portion 19a in contact with the divided pieces 11A of _A1 to _A4 is formed between _{X0 and} . Furthermore, as shown in FIG. 9B , the inclined surface portion 19 a in contact with the divided pieces 11A of B ₁ to B ₄ is formed between X _{1 to x2} .

Thereby, in the initial stage of fitting shown in FIGS. 9A and 9B , the divided pieces 11A of A ₁ to A ₄ are in a state of being deflected while being in contact with the inclined surface portion 19 a. In contrast, B ₁ to A 4 are in a state of being deflected. The divided piece 11A of B ₄ does not contact the inclined surface portion 19a and does not deflect.

Next, the state in which the outer joint pipe 7A is further pushed in from the position of FIGS. 9A and 9B is shown in FIGS. 9C and 9D , respectively. FIG. 9C shows that the outer joint pipe 7A is The state of being pushed in from the position shown in Fig. 9A. Fig. 9D shows a state in which the outer joint pipe 7A is pressed in from the position shown in Fig. 9B. That is, FIG. 9C and FIG. 9D are diagrams corresponding to the above-mentioned FIG. 1C and FIG. 1D respectively. Furthermore, the structure shown in FIGS. 9A to 9D is the same as the mechanical joint of the present invention described with reference to FIGS. 1A to 1D .

As shown in FIGS. 9C and 9D , when the divided pieces 11A of A ₁ to A ₄ are in contact with the flat surface 19 b and maintain the maximum deflection state, the divided pieces 11A of B ₁ to B ₄ are in contact with the inclined surface. 19a and the state of deflection. In this way, also in the second modification, the axial position at which each divided piece 11A reaches maximum deflection is the same position in the same group, but is different in each group. In other words, during the fitting process, the timing of reaching the maximum deflection of the divided pieces 11A of the same group is staggered. When the outer joint pipe 7A is further pressed in, the convex portion 13A is engaged with the concave portion 15A, and the joining is completed (the axial position of the convex portion 13A at this time is denoted as X ₃ ). Other structures are the same as in the first embodiment.

(Third modification)

Next, the third modification example will be described. That is, in the example shown in FIGS. 1A to 1D , both the convex portion 13 of the inner joint pipe 5 and the guide portion 19 of the outer joint pipe 7 have the inclined surface portion 13 a and the inclined surface portion 19 a , but the convex portion may also be provided only in the convex portion 13 of the outer joint pipe 7 . One of the guide portion 13 and the guide portion 19 is formed with an inclined surface. If any of the convex portion 13 and the guide portion 19 is formed with an inclined surface portion, the divided piece 11 can be deflected using the press-in load of the inner joint pipe 5 . Therefore, as another aspect of the mechanical joint 1 of FIGS. 1A to 1D , an example in which the convex portion 13 is formed with an inclined surface 13 a and the guide portion 19 is not formed with an inclined surface 19 a is shown in FIGS. 10A to 10D .

Figure 10A is a cross-sectional view of the divided pieces 11 of A ₁ to A ₄ and the guide portion 19 of the portion in contact with the divided pieces 11 of A ₁ to A ₄ , and Figure 10B is a sectional view of the divided pieces 11 of B ₁ to B ₄ and the guide portion 19 A cross-sectional view of the guide portion 19 of the portion where the divided pieces 11 of B ₁ to B ₄ are in contact. 10A and 10B show an initial state in which the inner joint pipe 5 is inserted into the outer joint pipe 7 . 10C and 10D respectively show a state in which the inner joint pipe 5 is further inserted from the position of FIGS. 10A and 10B.

As shown in FIGS. 10A to 10D , when the inclined surface portion 19 a is not formed in the guide portion 19 , the inclined surface portion 13 a of the convex portion 13 and the tip side corner portion of the guide portion 19 (the tip side end of the flat surface portion 19 b part) are in pressing contact, whereby the divided piece 11 is deflected in the radially inner direction.

In the case of this example, the position where the divided pieces 11 of A ₁ to A ₄ come into contact with the guide part 19 is different from the position where the divided pieces 11 of B ₁ to B ₄ contact the guide part 19 in the axial direction. , so that the period of reaching maximum deflection can be staggered in units of divided pieces of the same group. The above example is an example in which the inclined surface portion 13a is formed on the convex portion 13 and the inclined surface portion 19a is not formed on the guide portion 19. However, the inclined surface portion 19a is formed on the guide portion 19 and the inclined surface portion 13a is not formed on the convex portion 13. The same situation applies.

Originally, the fitting load differs depending on the axial length of the inclined surface (specifically, when the axial length of the inclined surface is long, the fitting load becomes smaller), so only between the convex portion 13 and the guide portion 19 When one of them forms an inclined surface, when the inclined surface is provided on the guide portion 19 side, the axial length of the inclined surface can be ensured and is reasonable.

Furthermore, the guide portion 19 of the outer joint pipe 7 (gray in FIGS. 1A to 1D The colored part) can be integrated with the outer joint pipe 7, or can be manufactured in the form of other components and installed on the inner peripheral surface of the outer joint pipe 7. For example, the engaging portion 17 of the outer joint pipe 7 is a part that resists the tensile load together with the convex portion 13 of the inner joint pipe 5 during fitting, and therefore requires strong durability. However, the guide portion 19 is only used during insertion. The extrusion load acts, but the load does not act during fitting, so strong durability is not required. Therefore, the guide part 19 can also be made in the form of other components with a strength similar to ordinary steel, and installed on the inner peripheral surface of the outer joint pipe 7 by screws or welding. In this case, the screws or welding can also be minimal. .

Moreover, when the guide part 19 is installed in the form of other components, the guide part 19 can also be brought into contact with the engaging part 17 as shown in FIGS. 14A to 14D , as long as the maximum deflection of the divided piece 11 can be maintained until the engagement is reached. Up to the joint 17, there may be a gap as shown in Figure 1A to Figure 1D.

In the above embodiment, the mechanical joint installed at the end of the steel pipe has been described. However, the outer joint pipe and/or the inner joint pipe in the mechanical joint may be welded in advance in a factory or the like. Installed on the end of the steel pipe to produce a steel pipe with a joint. That is, the steel pipe with a joint includes the inner joint pipe and/or the outer joint pipe of the mechanical joint described in the embodiment at both ends or at one end.

In addition, by connecting a plurality of steel pipes with joints at a construction site, etc., structures such as steel pipe piles, steel pipe sheet piles, steel pipe sheet pile walls, steel pipe columns, and steel pipe beams formed by connecting steel pipe sheet piles can be formed. That is, these structures include the mechanical joint described in the above embodiment and a plurality of steel pipes joined via the mechanical joint.

In the case of construction of these structures, as long as the restrictions become When one of the jointed steel pipes is connected, the mechanical joint of the other jointed steel pipe is aligned with the mechanical joint of the one of the jointed steel pipes, and then they are inserted and fitted. For example, when the structure is a steel pipe pile or the like, as long as either a steel pipe with an outer joint pipe attached to an end or a steel pipe with an inner joint pipe attached to an end is erected in the ground, the In this state, another steel pipe is placed on one of the steel pipes by lifting it with a crane, inserting the inner joint pipe into the outer joint pipe, and fitting the inner joint pipe and the outer joint pipe to join.

In addition, the mechanical joint of the present invention is configured to reduce the load required for insertion and offset the horizontal stress during insertion, so there is no need to restrict the horizontal movement of the upper steel pipe suspended by a crane during construction.

Furthermore, in the above description, a mechanical joint is described as an article, but the mechanical joint is designed by the following design method. That is, the design method of a mechanical joint designs a mechanical joint. The mechanical joint includes an inner joint pipe and an outer joint pipe, which are respectively provided at the ends of the steel pipes to be joined. The inner joint pipe and the outer joint pipe Any one of them includes divided pieces divided at equal intervals in the circumferential direction and flexible in the radial direction, and the mechanical joint includes: a convex portion formed on the outer peripheral surface of the inner joint pipe; an engaging portion, It is formed on the inner circumferential surface of the outer joint pipe, engages with the convex part in a state where the inner joint pipe and the outer joint pipe are fitted together, and resists tensile load together with the convex part; and a guide portion provided on the front end side of the outer joint pipe than the engaging portion, and abuts against the convex portion during fitting of the inner joint pipe and the outer joint pipe, and Place The convex portions cooperate to deflect the divided pieces and maintain the deflected state until the engaging portion, and in the method of designing the mechanical joint, the divided pieces are grouped so as to satisfy the following For multiple sets of conditions (1) and (2), during the fitting process, the timing of reaching the maximum deflection is staggered in units of divided pieces of the same group, and the horizontal deflection caused by the deflection of the divided pieces is shifted. Stress offset.

(1) The split pieces belonging to the same group have the same axial position where maximum deflection occurs in the guide portion, and the axial positions in each group are different.

(2) For divided pieces belonging to the same group, if the centers of the adjacent divided pieces in the circumferential direction are connected with a straight line, a straight line passing through the center of the tube or a polygon whose center of gravity coincides with the center of the tube will be formed.

Furthermore, another example of a mechanical joint is designed using the following design method. That is, the design method of a mechanical joint designs a mechanical joint. The mechanical joint includes an inner joint pipe and an outer joint pipe, which are respectively provided at the ends of the steel pipes to be joined. The inner joint pipe and the outer joint pipe Any one of them includes divided pieces divided at equal intervals in the circumferential direction and flexible in the radial direction, and the mechanical joint includes: a convex portion formed on the inner peripheral surface of the outer joint pipe; and an engaging portion , is formed on the outer peripheral surface of the inner joint pipe, is engaged with the convex portion in a state where the outer joint pipe and the inner joint pipe are mated, and resists the tensile load together with the convex portion; and a guide portion provided on the distal end side of the inner joint pipe than the engaging portion, and abuts on the convex portion during fitting of the outer joint pipe and the inner joint pipe, and The convex portion cooperates to deflect the divided piece and maintains the deflected state until the engaging portion, and the method for designing the mechanical joint , the divided pieces are grouped into multiple groups that satisfy the following conditions (1) and (2). During the fitting process, the timing of reaching the maximum deflection is staggered based on the divided pieces of the same group, and the The horizontal stress caused by the deflection of the split piece is offset.

(1) The split pieces belonging to the same group have the same axial position where maximum deflection occurs in the guide portion, and the axial positions in each group are different.

(2) For divided pieces belonging to the same group, if the centers of the adjacent divided pieces in the circumferential direction are connected with a straight line, a straight line passing through the center of the tube or a polygon whose center of gravity coincides with the center of the tube will be formed.

The embodiments of the present invention have been specifically described above. However, the present invention is not limited to the above-described embodiments. Various modifications based on the technical idea of the present invention or a combination of mutual embodiments or modifications may be adopted. For example, in the second modified example, the guide portion 19A or the recessed portion 15A may be provided on the inner peripheral surface of the outer joint pipe 7A, and the convex portion 13A may be provided on the outer peripheral surface of the inner joint pipe 5A.

[Industrial availability]

The present invention is suitable for joining steel pipes to each other and is preferably used.

1: Mechanical joint

5: Inner joint pipe

7:Outside joint pipe

9: Base end

11. A ₁ ~ A ₄ , B ₁ ~ B ₄ : split slices

13:convex part

13a, 19b: tilted face

15: concave part

17: Engagement part

19: Guidance Department

19a: Inclined face

X ₀ ~X ₃ : Axial position

Claims (9)

A mechanical joint includes an inner joint pipe and an outer joint pipe, each of which is provided at the end of a steel pipe to be joined, and any one of the inner joint pipe and the outer joint pipe is included at equal intervals in the circumferential direction. A segmented piece that is divided and can be flexed in the radial direction, and the mechanical joint includes: a convex portion formed on the outer peripheral surface of the inner joint pipe; and an engaging portion formed on the inner peripheral surface of the outer joint pipe, When the fitting of the inner joint pipe and the outer joint pipe is completed, it is engaged with the convex part and resists the tensile load together with the convex part; and a guide part is provided on the outer joint pipe. on the front end side than the engaging portion, abuts on the convex portion in the middle of fitting the inner joint pipe and the outer joint pipe, and cooperates with the convex portion to cause the dividing piece to flex bend, and maintain the deflected state until the engaging portion, and the divided pieces are grouped into a plurality of groups that satisfy the following conditions (1) and (2), and are configured so that during the fitting process The timing of reaching the maximum deflection is staggered based on the divided pieces of the same group; (1) the axial positions of the divided pieces that belong to the same group where the maximum deflection occurs in the guide portion are the same, and the maximum deflection in each group is The axial positions are different; (2) For divided pieces belonging to the same group, if the centers of adjacent divided pieces in the circumferential direction are connected by a straight line, a straight line passing through the center of the tube or the center of gravity will be formed A polygon aligned with the center of the tube. A mechanical joint includes an inner joint pipe and an outer joint pipe, each of which is provided at the end of a steel pipe to be joined, and any one of the inner joint pipe and the outer joint pipe is included at equal intervals in the circumferential direction. A segmented piece that is divided and can be flexed in the radial direction, and the mechanical joint includes: a convex portion formed on the inner peripheral surface of the outer joint pipe; and an engaging portion formed on the outer peripheral surface of the inner joint pipe, When the fitting of the outer joint pipe and the inner joint pipe is completed, it is engaged with the convex part and resists the tensile load together with the convex part; and a guide part is provided on the inner joint pipe on the distal end side than the engaging portion, abuts on the convex portion in the middle of fitting the outer joint pipe and the inner joint pipe, and cooperates with the convex portion to cause the dividing piece to flex bend, and maintain the deflected state until the engaging portion, and the divided pieces are grouped into a plurality of groups that satisfy the following conditions (1) and (2), and are configured so that during the fitting process The timing of reaching the maximum deflection is staggered based on the divided pieces of the same group; (1) the axial positions of the divided pieces that belong to the same group where the maximum deflection occurs in the guide portion are the same, and the maximum deflection in each group is The axial positions are different; (2) For divided pieces belonging to the same group, if the centers of adjacent divided pieces in the circumferential direction are connected by a straight line, a straight line passing through the center of the tube or the center of gravity will be formed A polygon aligned with the center of the tube. The mechanical joint as claimed in claim 1 or claim 2, wherein the divided pieces of the other groups do not start to deflect in the radial direction before the divided pieces of one group reach maximum deflection. A steel pipe with a joint, including an inner joint pipe and/or an outer joint pipe in the mechanical joint as described in any one of claims 1 to 3 at both ends or at one end. A method of manufacturing a steel pipe with a joint, which includes manufacturing a steel pipe with a joint as described in Claim 4, and installing the pipes as described in any one of Claims 1 to 3 on the ends of the steel pipes to be joined. The outer joint pipe and/or the inner joint pipe in mechanical joints. A structure including a mechanical joint, including: the mechanical joint as described in any one of claim 1 to claim 3; and a plurality of steel pipes joined by the mechanical joint. A construction method of a structure including a mechanical joint, which constructs a structure including a mechanical joint as described in claim 6, and installs a steel pipe with the outer joint pipe at the end, and a steel pipe with the outer joint pipe installed at the end. Any one of the steel pipes with the inner joint pipe is placed erected in the ground. In this state, another steel pipe is arranged on one of the steel pipes, so that the inner joint pipe and the outer joint pipe Fitting and joining. A design method for mechanical joints, designing mechanical joints, so The mechanical joint includes an inner joint pipe and an outer joint pipe, which are respectively provided at the ends of the steel pipes to be joined, and each of the inner joint pipe and the outer joint pipe is divided into equal intervals in the circumferential direction. and a segmented piece that can be flexed in the radial direction, and the mechanical joint includes: a convex portion formed on the outer peripheral surface of the inner joint pipe; and an engaging portion formed on the inner peripheral surface of the outer joint pipe. The inner joint pipe and the outer joint pipe are engaged with the convex part in a state where the fitting is completed, and resist the tensile load together with the convex part; and a guide part is provided on the outer joint pipe. The distal end side of the engagement portion abuts against the convex portion in the middle of fitting the inner joint pipe and the outer joint pipe, and cooperates with the convex portion to flex the divided piece. , and maintain the deflected state until the engaging portion, and in the design method of the mechanical joint, the divided pieces are grouped into a plurality of pieces that satisfy the following conditions (1) and (2) Group, during the fitting process, the timing of reaching the maximum deflection is staggered with the divided pieces of the same group as a unit, and the horizontal stress generated by the deflection of the divided pieces is offset; (1) The divided pieces belonging to the same group The axial position that produces the maximum deflection in the guide part is the same, and the axial position in each group is different; (2) For the divided pieces belonging to the same group, if the adjacent divided pieces are aligned with each other in a straight line By connecting the centers in the circumferential direction, a straight line passing through the center of the tube or a polygon whose center of gravity coincides with the center of the tube is formed. A method for designing a mechanical joint. Designing a mechanical joint. The mechanical joint includes: an inner joint pipe and an outer joint pipe, which are respectively provided at the ends of the steel pipes to be joined. The inner joint pipe and the outer joint Each of the tubes includes divided pieces that are divided at equal intervals in the circumferential direction and can be flexed in the radial direction, and the mechanical joint includes: a convex portion formed on the inner peripheral surface of the outer joint tube; and an engaging portion. The portion is formed on the outer peripheral surface of the inner joint pipe, engages with the convex portion in a state where the outer joint pipe and the inner joint pipe are completely fitted, and resists the tensile load together with the convex portion. ; and a guide portion provided on the top end side of the inner joint pipe than the engaging portion, and abuts against the convex portion in the middle of fitting the outer joint pipe and the inner joint pipe, The divided pieces are deflected in cooperation with the convex portion, and the deflected state is maintained until the engaging portion, and in the method of designing the mechanical joint, the divided pieces are grouped to satisfy For multiple sets of the following conditions (1) and (2), the timing of reaching the maximum deflection is staggered in units of divided pieces of the same group during the fitting process, and the level caused by the deflection of the divided pieces is shifted. The stress in the direction cancels out; (1) The axial position where the maximum deflection occurs in the guide part of the segmented pieces belonging to the same group is the same, and the axial position in each group is different; (2) For the segmented pieces belonging to the same group If the adjacent divided pieces are connected by a straight line to the centers in the circumferential direction, a straight line passing through the center of the tube or the center of gravity will be formed. A polygon aligned with the center of the tube.