JP4600407B2 - Steel pipe joint structure - Google Patents

Description

  The present invention relates to a joint structure and a joining method in the pipe axis direction of steel pipes, for example, steel pipe piles and ready-made concrete piles (PHC piles, PRC piles, SC piles).

Steel pipe piles such as soil cement synthetic steel pipe piles are generally constructed by jointing them at the construction site by welding.
However, with joints by welding, (1) the quality of the welded part depends on the skill of the welder, and (2) the construction depends on the weather. It was rare.

As a steel pipe connection method instead of welding, for example, there is a steel pipe connection structure disclosed in Japanese Patent Application Laid-Open No. 11-81304.
FIG. 13 is an explanatory view of a steel pipe connection structure disclosed in the publication. An outline of the steel pipe connection structure disclosed in the publication is as follows.
Cylindrical connecting portions 51 and 71 having an outer diameter smaller than the diameter of the steel pipe pile are fixed to the butted edge portions 60a and 61a of the steel pipe piles 60 and 61 to be connected. Then, screw holes 53 and 73 are provided on the side surfaces of the cylindrical connection parts 51 and 71, and the cylindrical connection parts 51 and 71 are abutted. Furthermore, the outer periphery of these cylindrical connection portions 51 and 71 is covered with a divided cylindrical joint 56 that is divided into arcs and has bolt insertion holes, and each of the bolt insertion holes of each of the divided cylindrical joints 56 and each of the above-described parts. The steel pipe piles 60 and 61 are connected to each other by matching the screw holes 53 and 73 and tightening them with bolts 62.

JP-A-11-81304

However, the steel pipe connection structure described in JP-A-11-81304 has the following problems.
The split cylindrical joint 56 is used separately from the steel pipe pile, and in order to integrate it, not only the upper joint and the lower joint are engaged, but also the precision considering the engagement of the divided cylindrical joint 56 and the upper and lower joints. High production is required, production is difficult, and production cost is high.
Moreover, the work which separately conveys and attaches the divided cylindrical joint 56 is necessary, and the workability is poor.
Furthermore, when the diameter of the steel pipe joint is increased and the wall thickness is increased, the weight of the split cylindrical joint 56 increases, and transportability and workability are further improved, such as the need to bring a new heavy equipment for transportation such as a crane. There is a problem of getting worse.
The present invention has been made to solve the above problems.

The steel pipe joint structure according to the present invention includes an outer joint pipe and an inner joint pipe provided at the joint end of the steel pipe to be joined, and the outer joint pipe and the inner joint pipe are inserted into each other in the pipe axial direction. A steel pipe joint structure, which is formed on one of the outer joint pipe or the inner joint pipe, and a slit that divides them into a plurality of circumferential directions, and a convex part formed on the outer peripheral surface of the inner joint pipe, An engaging portion that is formed on an inner peripheral surface of the outer joint pipe and engages with the convex portion in a state in which the inner joint pipe is inserted into the outer joint pipe and resists a tensile load together with the convex portion; A contact portion that resists a compressive load in a state where the inner joint pipe is inserted into the outer joint pipe, and is formed at a portion other than the portion where the convex portion is formed on the distal end side of the inner joint pipe. And the base end side of the convex part The outer diameter of the reduced diameter portion is a site, the smaller than the inner diameter of the outer joint tube, the contact portion has a side of the distal end portion which is not divided among the outer joint tube or inner joint tube, divided side In the state which inserted the said inner joint pipe in the said outer joint pipe, both were fastened with the volt | bolt.

Also, the outer diameter of the portion where the convex portion is formed in the inner joint pipe is set larger than the minimum inner diameter in the outer joint pipe,
In the middle of inserting the inner joint pipe into the outer joint pipe, the convex portion presses and contacts the inner peripheral surface of the outer joint pipe, so that the slit is formed in the outer joint pipe or the inner joint pipe. The bent side is bent in the radial direction, and when the insertion is completed, the bending is returned and the convex portion is engaged with the engaging portion.
Note that the return of the bending includes a case where the elastically deformed one is automatically returned by an elastic action, and a case where the plastically deformed one is forcibly returned by other means.

Also, an inner peripheral surface is provided on the outer peripheral surface of the inner joint pipe, which is inclined toward the distal end side from the top of the convex portion in the diameter reducing direction, and is located on the proximal end side from the distal end portion or the distal end portion of the outer joint pipe. Further, an inclined surface that is inclined inward and is opposed to the inclined surface of the inner joint pipe is provided.

  Further, the inner joint pipe and the outer joint pipe are made of a material having a strength higher than that of the steel pipe to be joined.

In the present invention, a steel pipe joint structure for connecting steel pipes by inserting an outer joint pipe and an inner joint pipe into each other in the pipe axial direction, which is formed on one of the outer joint pipe or the inner joint pipe, In the circumferential direction, a convex portion formed on the outer peripheral surface of the inner joint pipe, an inner peripheral surface of the outer joint pipe, and the inner joint pipe inserted into the outer joint pipe An engaging portion that engages with a convex portion and resists a tensile load together with the convex portion, and an abutting portion that resists a compressive load when the inner joint pipe is inserted into the outer joint pipe. The outer diameter of the reduced diameter portion, which is a portion other than the portion formed on the distal end side of the inner joint pipe and where the convex portion is formed, is a portion closer to the base end side than the convex portion. Smaller than the inner diameter of the outer joint pipe Is composed of a front end portion of the inner joint pipe that is not divided and a stepped portion formed on the base end side of the divided side, and both in a state where the inner joint pipe is inserted into the outer joint pipe. With bolts, the separate cylindrical joints separate from the steel pipe piles required in the prior art are no longer required, the transportability and workability that have become problems in the past have been greatly improved, and manufacturing has become easier. Production costs can also be reduced.

Embodiment 1 FIG.
1 is a perspective view of one embodiment of the present invention, and FIG. 2 is a cross-sectional view taken along line AA in FIG. 1 (however, FIG. 1 shows a state before joining, and FIG. 2 shows a state after joining). ). As shown in FIGS. 1 and 2, this embodiment includes an outer joint pipe 3 attached to one steel pipe 1 to be connected and an inner joint pipe 33 attached to the other steel pipe 31 to be connected. .
The outer joint pipe 3 has a cylindrical shape, and an inclined surface 5 that is inclined inward is formed at the tip of the outer joint pipe 3.
Further, a concave portion 7 is formed on the inner peripheral surface of the base end side (steel pipe 1 side) of the outer joint pipe 3 so as to be recessed outward at a depth h. In addition, a plurality of through holes 11 for inserting bolts 9 are provided on the proximal end side of the outer joint pipe 3 at regular intervals in the circumferential direction.

The inner joint pipe 33 basically has a cylindrical shape, and is formed with the same diameter part 33a having the same diameter as the steel pipe 31 on the base end side, and the steel pipe 31 is welded to the end part of the same diameter part 33a. . A diameter-reduced portion 33b that is reduced in diameter via a stepped portion 34 is formed on the distal end side of the same-diameter portion 33a.
The reduced diameter portion 33b is divided into a plurality of circumferential directions by slits extending in the axial direction. A stepped portion 35 having a height h protruding outward is formed at a position closer to the tip than the center of the reduced diameter portion 33b. An inclined surface 37 that is inclined in the direction of diameter reduction from the top of the step portion 35 toward the distal end side is formed continuously with the step portion 35. A bolt hole 39 in which a screw is cut is provided on the further end side of the inclined surface 37. The bolt hole 39 is provided at a position facing the through hole 11 provided in the outer joint pipe 3 in a state where the steel pipes 1 and 31 are connected, that is, in a state where the inner joint pipe 33 is inserted into the outer joint pipe 3. .

The joining state of the outer joint pipe 3 and the inner joint pipe 33 will be described with reference to FIG.
In the joined state, the distal end portion 3 a of the outer joint pipe 3 is in contact with a step portion 34 formed on the proximal end side of the inner joint pipe 33. Stress transmission in the tube axis compression direction is performed at the contact surface between the tip of the outer joint tube 3 and the stepped portion 34.
Further, the inner peripheral surface of the outer joint pipe 3 is in contact with the outer peripheral surface of the reduced diameter portion 33 b of the inner joint pipe 33. The stepped portion 35 of the inner joint pipe 33 is engaged with the side wall 7 a of the recessed portion 7 of the outer joint pipe 3. That is, the side wall 7a constitutes the engaging portion of the present invention.
Further, a bolt 9 (see FIG. 1) is inserted from the through hole 11 of the outer joint pipe 3 to the bolt hole 39 of the inner joint pipe 33 to fasten them together.

In the present embodiment configured as described above, the compression direction of the pipe shaft is resisted by the abutting portion between the tip 3a of the outer joint pipe 3 and the step 34 of the inner joint pipe 33. Further, the pulling direction of the pipe shaft is resisted by the engaging portion of the side wall 7 a of the recessed portion 7 in the outer joint pipe 3 and the step portion 35 of the inner joint pipe 33.
As described above, in the present embodiment, basic stress transmission is performed at the contact portion and the engagement portion between the outer joint pipe 3 and the inner joint pipe 33. However, when a strong tensile force is applied, the reduced diameter portion 33b of the inner joint pipe 33 may be bent and the engaging portion may be disengaged, so that the bolt 9 prevents this. That is, the bolt 9 is only an auxiliary means.

The effect | action at the time of the connection of this Embodiment comprised as mentioned above is demonstrated based on FIGS. 3-5 which are explanatory drawings of the process which reaches a steel pipe joining state.
In a factory or the like, the outer joint pipe 3 and the inner joint pipe 33 are fixed to the connecting portions of the steel pipes 1 and 31 in advance by welding.
In the state as described above, the steel pipes 1 and 31 are brought into the field, and the tip of the lower steel pipe 1 on which the outer joint pipe 3 is not fixed is driven into the soil. When the driving progresses and the upper steel pipe 31 is connected, the tip of the inner joint pipe 33 fixed to the upper steel pipe 31 is brought into contact with the lower outer joint pipe 3.

At this time, by providing an inclined surface inclined inwardly at the tip of the lower outer joint pipe 3, the opening of the outer joint pipe 3 becomes larger than the tip diameter of the reduced diameter portion 33b of the inner joint pipe 33. Therefore, insertion can be started smoothly.
Moreover, when the front-end | tip part of the inner joint pipe 33 is inserted in the outer joint pipe 3, the inclined surface 5 formed in the outer joint pipe 3 contacts the inclined surface 37 of the inner joint pipe 33 (see FIGS. 3 and 4). By the action of these inclined surfaces, the force in the tube axis direction is converted into a vector in the radial direction, and the divided reduced diameter portion 33b can be bent in the radially inward direction. Thereby, the inner joint pipe 33 can be further inserted, and the inner joint pipe 33 is inserted in a bent state as shown in FIG.

  Thereafter, the insertion is advanced with the reduced diameter portion 33b bent in the radially inward direction (see FIG. 5), and when the distal end portion 3a of the outer joint pipe 3 comes into contact with the step 34 formed on the inner joint pipe 33. The step portion 35 of the inner joint pipe 33 engages with the side wall 7a of the recessed portion 7 of the outer joint pipe 3, and the bending is returned to complete the joining of the steel pipe. In this completed state, the outer joint pipe 3 and the inner joint pipe 33 are, as shown in FIG. A step portion 35 of the inner joint pipe 33 is engaged with the side wall 7 a of the recessed portion 7 of the joint pipe 3.

  The stress at the connecting portion of the steel pipes connected as described above resists the compressive force by the bearing pressure of the end 3a of the outer joint pipe 3 and the step 34 of the inner joint pipe 33. Further, the tensile force is resisted by shearing and supporting pressure of the side wall 7a of the recessed portion 7 of the outer joint pipe 3 and the step 35 of the inner joint pipe 33.

As described above, in the present embodiment, the reduced diameter portion 33b of the inner joint pipe 33 is divided into a plurality of parts, so that it can be easily deformed radially inward at the time of joining and can be connected with its own weight or a small pushing load. .
Further, since the compressive load after joining is transmitted by the distal end portion 3a of the outer joint pipe 3 that is not divided and the step portion 34 of the inner joint pipe 33, breakage due to buckling can be prevented.

Embodiment 2. FIG.
FIG. 6 is an explanatory diagram of Embodiment 2 of the present invention. In FIG. 6, the same parts as those in FIG. 2 showing the first embodiment are denoted by the same reference numerals.
In this embodiment, the outer diameter of the reduced diameter portion 33b (the portion other than the portion where the step portion 35 is formed) of the inner joint tube 33 is set smaller than the inner diameter of the outer joint tube 3. That is, a gap g is formed between the two as shown in FIG.
Thus, by providing the initial clearance between the inner peripheral surface of the outer pipe joint tube 3 and the outer peripheral surface of the reduced diameter portion 33b of the inner pipe joint tube 33, the radial deformation due to bending during pressing can be reduced. Therefore, it can be inserted with a small pushing load.

  In this case, the engagement of the stepped portion 35 becomes shallow, but as shown in FIG. 6, by tightening with the bolt 9, the distal end portion of the divided reduced diameter portion 33b is expanded outward, and the recessed portion 7 The engagement between the side wall 7a and the stepped portion 35 can be deepened to increase the area of the hooked portion.

In the above example, the outer diameter of the reduced diameter portion 33 b of the inner joint pipe 33 is set smaller than the inner diameter of the outer joint pipe 3, but the step portion 35 is in press contact with the inner peripheral surface of the outer joint pipe 3 during the insertion. Therefore, an increase in the pushing load accompanying the pressing contact is inevitable.
Therefore, if the outer diameter of the portion where the step portion 35 is formed is set to be smaller and the gap g> h (the height of the step portion) is set, the step portion 35 is attached to the outer joint pipe 3 during the insertion. It can be prevented from being pressed against the inner peripheral surface. If it does in this way, the pushing load at the time of pipe connection can be made still smaller.

Embodiment 3 FIG.
FIG. 7 is an explanatory diagram of Embodiment 3 of the present invention. In the third embodiment, the position of the inclined surface 5 formed on the inner surface of the outer pipe joint pipe 3 is compared with the first embodiment from the distal end of the outer pipe joint pipe 3 to the back (base end side). It is what was positioned. By doing in this way, the space | interval of the relative position of the upper and lower steel pipes 1 and 31 just before joining becomes small, and centering construction becomes easy.
In addition, as shown in FIG. 7, it can also be regarded as a convex part between the inclined surface 5 of the inner surface of the outer pipe joint pipe 3, and the recessed part 7, and an engaging part can also be comprised by such a convex part. it can. FIG. 7 shows an example in which the through hole 40 is provided at the end of the inner pipe joint pipe 33 and the nut 41 is welded and attached to the inside thereof, thereby providing the same effect as the bolt hole 39 of the first embodiment. ing.

Embodiment 4 FIG.
While the first to third embodiments focus on the joining of steel pipes, the fourth embodiment focuses on separating connected steel pipes.
8 and 9 are explanatory views of the fourth embodiment, and the same reference numerals are given to the same parts as those in FIG. 3 showing the first embodiment.
In the fourth embodiment, the through hole provided in the outer joint pipe 3 is used as the screw hole 21, and the diameter thereof is set larger than the diameter of the bolt hole 39 provided at the end of the inner joint pipe 31.

  In the present embodiment configured as described above, the bolt 23 is inserted into the screw hole 21 formed in the outer joint pipe 3 and screwed. Then, as shown in FIG. 8, the tip of the bolt 23 pushes the reduced diameter portion 33b of the inner joint pipe 33 inward. Therefore, the reduced diameter portion 33 b is deformed inward, and the engagement between the side wall 7 a of the recessed portion 7 of the outer joint pipe 3 and the step portion 35 of the inner joint pipe 33 is released. In this state, as shown in FIG. 9, the joint can be separated by applying a pulling load to the inner pipe joint pipe 33.

In the above-described embodiment, an example in which the side (inner joint pipe 33) to be inserted inside is divided is shown.
However, the present invention is not limited to this, and the side (outer joint pipe 3) disposed outside may be divided as shown in FIG.
In this case, in the connected state, the distal end portion of the inner joint pipe 33 and the proximal end side inner peripheral surface of the outer joint pipe 3 are brought into contact with each other, and compression stress is transmitted on the contact surface. If it does in this way, since the compressive load after joining can be transmitted in the part which is not divided, destruction by buckling can be prevented.

  In the above embodiment, the one-stage locking portion is shown, but it may be two-stage as shown in FIGS. Alternatively, it may be a multi-stage of three or more stages.

  Further, by forming the outer joint pipe 3 and the inner joint pipe 33 with a material having a strength higher than that of the steel pipe to be joined, the length of the hook portion (for example, the height of the step portion 35 of the inner joint pipe 33). h) The thickness of the divided joint pipe can be reduced. Further, a material having a high strength has a large limit to behave elastically, and combined with a decrease in the thickness of the joint tube sheet, provides a good return performance against a large deformation. As a result, it becomes possible to insert with the same length with a small indentation load, and the necessary split length with respect to the same indentation load becomes small, and the joint length can be shortened.

It is a perspective view explaining the joint structure of the steel pipe concerning one embodiment of the present invention. It is sectional drawing of the joining state of one Embodiment shown in FIG. It is explanatory drawing of the joining progress of one Embodiment shown in FIG. It is an enlarged view which expands and shows a part (circled part A) of FIG. It is explanatory drawing of the joining progress of one Embodiment shown in FIG. It is sectional drawing of other embodiment of this invention. It is sectional drawing of other embodiment of this invention. It is explanatory drawing of other embodiment of this invention. It is explanatory drawing of other embodiment of this invention. It is explanatory drawing of other embodiment of this invention. It is explanatory drawing of other embodiment of this invention. It is explanatory drawing of other embodiment of this invention. It is explanatory drawing of the joint structure of the conventional steel pipe.

Explanation of symbols

1,31 steel pipe
3 Outer joint pipe 5 Inclined surface 7 Recessed part 9 Bolt 11 Through hole 33 Inner joint pipe 33a Same diameter part 33b Reduced diameter part 35 Step part 39 Bolt hole

Claims (4)

A steel pipe joint structure in which an outer joint pipe and an inner joint pipe are provided at the joint ends of steel pipes to be joined, and these outer joint pipes and inner joint pipes are inserted into each other in the pipe axial direction to connect the steel pipes. ,
A slit formed on one of the outer joint pipe or the inner joint pipe and dividing them into a plurality of circumferential directions,
A convex portion formed on the outer peripheral surface of the inner joint pipe;
An engaging portion that is formed on an inner peripheral surface of the outer joint pipe, engages with the convex portion in a state in which the inner joint pipe is inserted into the outer joint pipe, and resists a tensile load together with the convex portion;
A contact portion that resists a compressive load in a state in which the inner joint pipe is inserted into the outer joint pipe;
The outer diameter of the reduced diameter portion, which is a portion other than the portion formed on the distal end side of the inner joint pipe and where the convex portion is formed, is a portion closer to the base end side than the convex portion . Smaller than the inner diameter,
The contact portion is composed of a distal end portion that is not divided among the outer joint pipe or the inner joint pipe, and a step portion formed on the proximal end side of the divided side,
A steel pipe joint structure, wherein the inner joint pipe is fastened with bolts in a state where the inner joint pipe is inserted into the outer joint pipe. The outer diameter of the portion where the convex portion is formed in the inner joint pipe is set larger than the minimum inner diameter in the outer joint pipe,
In the middle of inserting the inner joint pipe into the outer joint pipe, the convex portion presses and contacts the inner peripheral surface of the outer joint pipe, so that the slit is formed in the outer joint pipe or the inner joint pipe. 2. The steel pipe joint structure according to claim 1, wherein the bent side is bent in a radial direction, and in the insertion completed state, the bending is returned and the convex portion is engaged with the engaging portion. Provided on the outer peripheral surface of the inner joint pipe an inclined surface inclined in the direction of diameter reduction from the top of the convex portion toward the distal end side, on the inner peripheral surface located on the proximal end side from the distal end portion or the distal end portion of the outer joint pipe, The steel pipe joint structure according to claim 1 or 2, further comprising an inclined surface that is inclined inward and is opposed to the inclined surface of the inner joint pipe. The steel pipe joint structure according to any one of claims 1 to 3, wherein the inner joint pipe and the outer joint pipe are formed of a material having a strength higher than that of the steel pipe to be joined.

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