JP6146336B2 - Steel pipe joints - Google Patents

Description

  The present invention relates to a joint for joining steel pipes constituting a structure to be placed in the ground, such as a steel pipe pile, a steel pipe sheet pile, and a built-up column.

Some steel pipe piles for preventing landslides and long support piles have a diameter of about 200 to 1500 mm and a length of several tens of meters depending on the conditions of the construction site.
In such a case, it is necessary to join short steel pipe piles at the construction site in the middle of placing the piles, and for this joining, joint joints attached to respective ends of the steel pipe piles to be joined are used.

As an example of such a joint, there is a “joint joint of steel pipe piles” disclosed in Patent Document 1.
The steel pipe pile joint is composed of a male cylinder having a male thread and a female cylinder having a female thread, each of which is provided at the end of the steel pipe pile, and the screw is a multi-thread with three or more parallel threads, It is characterized in that a cylindrical portion having an outer diameter that is loosely fitted to the inner diameter of the female screw is provided at the tip of the male side cylinder (see claim 1 of Patent Document 1).

Japanese Patent Laid-Open No. 10-311028

Since the thing of patent document 1 fits the cylindrical part in the internal diameter of the internal thread so that it can be positioned, the centering of the joint part can be performed in a short time when joining the upper pile and the lower pile in the field construction. It can be easily done and has excellent workability.
In the above-mentioned joint joint, since multi-threaded screws are used, the engagement of the screws starts at a large number of positions, and the shaft cores of the upper and lower piles are easily aligned with the positioning action of the cylindrical portion. (See paragraph [0010] of Patent Document 1).

Certainly, centering at the start of joining is important at the construction site, but it is also important to prevent misalignment at the time of completion of joining by the joint joint.
This is because if the joints of the joints are inconsistent, the load transmission area at the joints will be reduced, load transmission will not be performed properly, and the force from the difference in the joint area in the circumferential direction of the joints This is because it is possible that an unbalance occurs and bending which is not assumed in the design may occur.

In this respect, if there is no clearance at all in the threaded portion of the joint joint, there will be no difference.
However, there is a limit to the accuracy of manufacturing the steel pipe and the accuracy of attaching and processing the joined joint, and it is inevitable to provide a slight clearance in the threaded portion of the joined joint attached to the end of the steel pipe pile. Rather, it can be said that it is preferable that the clearance of the threaded portion of the joint joint is large in consideration of workability. For this reason, when the screw tightening is completed, there may be a deviation (mistake) of the clearance. In particular, when steel pipe piles have a large diameter, or when multi-threaded screws are used like the joint joint of Patent Document 1, the clearance becomes large in consideration of workability, and there is a high possibility that a mistake will occur. Become.
However, it is possible to prevent such mistakes by performing careful work using, for example, a guide during the joining work, but it takes time and effort to align the heavy pile body. It will damage the sex.
Thus, prevention of misunderstanding and improvement in workability are in a trade-off relationship.

As described above, the joint joint disclosed in Patent Document 1 can easily and reliably perform centering at the start of joining, but in terms of improving workability to completion after the start of screw tightening, There were still challenges.
In addition, said subject is not restricted to the joining joint of the steel pipe which comprises a steel pipe pile, For example, constructs structures other than the steel pipe pile formed in the ground, such as a steel pipe sheet pile and a construction column. The same is true for steel pipes.
The present invention has been made to solve such a problem, and an object of the present invention is to obtain a steel pipe joint that can improve the workability from the start of joining to the completion of screw tightening and has excellent workability.

(1) A steel pipe joint according to the present invention is a steel pipe joint that is attached to an end of a steel pipe constituting a structure to be placed in the ground and joins the steel pipes together.
A male side cylinder having a male thread consisting of three or more multi-threaded threads with parallel threads, and a female side cylinder having a female thread consisting of three or more multi-threaded threads with parallel threads;
A cylindrical portion having an outer diameter loosely fitted to the inner diameter of the female screw is provided at the tip of the male side cylinder,
In the state where the male screw of the male cylinder is screwed in and tightened, the tip of the female cylinder is configured to contact an outer peripheral seat formed on the male cylinder,
An inclined surface that is point-symmetric with respect to the center of the cylinder axis and that is inclined in the radial direction is formed over the entire circumference at the tip of the female side cylinder, and the male cylinder that is in contact with the inclined surface An inclined surface having the same inclination direction and inclination angle as the inclined surface is provided on the outer peripheral seat over the entire circumference.

(2) Further, in the above (1), the inclination angle with respect to the radial direction of the inclined surface is set in a range of 5 degrees to 25 degrees.

(3) Further, in the above-described (1) or (2), the free end of the female side tubular body and the radially inner side of the inclined surface at the outer peripheral seat of the male side tubular body are axially play with each other. The loose fitting portion to be fitted is formed over the entire circumference.

  In the steel pipe joint according to the present invention, the male side cylinder is provided with a cylindrical portion having an outer diameter loosely fitted to the inner diameter of the female thread, and the male thread of the male cylinder is screwed and tightened. The tip of the body is configured to contact the outer peripheral seat formed on the male cylinder, and the tip of the female cylinder is point-symmetric with respect to the center of the cylinder axis and is inclined in the radial direction Is formed over the entire circumference, and an inclined surface having the same inclination direction and inclination angle as the inclined surface is provided over the entire circumference on the outer peripheral seat of the male cylinder that contacts the inclined surface. The cylindrical portion is inserted into the internal diameter of the female thread of the female cylinder so that positioning is easy and excellent workability at the start of joining is formed on the male cylinder and female cylinder immediately before the completion of screwing. The axis of the male cylinder and the female cylinder is adjusted by contacting the inclined surface and guiding. In, can be prevented tongue and groove without a careful work using a guide or the like, can improve a series of operations of from the time of joining the start to the screw tightening completion, is excellent in workability.

It is explanatory drawing explaining the external appearance of the joint joint which concerns on one embodiment of this invention. It is explanatory drawing of the joint joint which concerns on one embodiment of this invention, and shows a part of longitudinal cross-sectional view. It is explanatory drawing explaining the effect | action of the joint joint which concerns on one embodiment of this invention. It is explanatory drawing explaining the function of the inclined surface in the joint joint which concerns on one embodiment of this invention. It is explanatory drawing of the joining method of the pile using the joint joint which concerns on one embodiment of this invention. It is explanatory drawing of the aspect of the inclined surface in the joint joint which concerns on one embodiment of this invention. It is explanatory drawing of the joint joint which concerns on other embodiment of this invention, and shows a part of longitudinal cross-sectional view. It is an enlarged view which expands and shows a part of FIG. It is explanatory drawing of the effect | action of the joint joint which concerns on other embodiment of this invention.

[Embodiment 1]
In the present embodiment, a steel pipe pile will be described as an example of a structure to be placed in the ground.
As shown in FIGS. 1 and 2, a steel pipe joint (hereinafter simply referred to as “joint joint”) constituting a steel pipe pile is a joint 3 that is attached to the end of the steel pipe 1 and joins the steel pipes 1 to each other. It is composed of a male side cylindrical body 5 having a male screw made up of three or more multi-threaded screws with parallel screws and a female side cylinder 7 having a female screw made up of three or more multi-threaded screws with parallel screws.
In addition, what is shown in FIG. 1 is a 4 thread | screw, and when it sees from the front, the screw start end part 9 is visible at three places.
And the cylindrical part 11 which has the outer diameter loosely fitted in the internal diameter of a female screw is provided in the front-end | tip of the male side cylinder 5. As shown in FIG.

In the state where the male screw of the male cylinder 5 is screwed and tightened, as shown in FIG. 2, the female tip portion 13 of the female cylinder 7 abuts on the outer peripheral seat 15 formed on the male cylinder 5. It is configured as follows.
In order to do this, as shown in FIG. 2, in the state where the male screw of the male cylinder 5 is screwed and tightened, the male front end 17 of the male cylinder 5 and the inner peripheral seat of the female cylinder 7 What is necessary is just to make a clearance gap between 19 and 19. But you may make it the front-end | tip part of the male side cylinder 5 and the inner peripheral seat 19 of the female side cylinder 7 contact | abut simultaneously with the completion of joining by the joining joint 3. FIG.

Further, the entire circumference of the distal end portion of the female side cylindrical body 7 is point-symmetric with respect to the center of the cylinder axis, and is female with an inclination angle α that is inclined downward in the radially outward direction with the distal end portion facing upward. A side inclined surface 13a is formed. A preferable value of the inclination angle α will be described later.
On the other hand, on the outer peripheral seat 15 of the male cylinder 5 that contacts the female inclined surface 13a, a male inclined surface 15a having the same inclination direction and the same inclination angle as the female inclined surface 13a is provided in the joined state. It has been.

The operation of the joint joint 3 configured as described above will be described.
By providing the cylindrical portion 11 having an outer diameter loosely fitted to the inner diameter of the female screw at the tip of the male side cylindrical body 5, the cylindrical portion 11 serves as a guide at the start of pile joining to promote screw engagement, and easy to align the center. And improve workability at the start of pile joining.
In addition, since four-thread multi-threads are used, screw engagement begins at four locations, and the axial center of the upper and lower piles can be easily aligned with the positioning action of the cylindrical portion 11 described above. Can do.
Further, in the case of a four-thread screw, since the lead in the axial direction becomes four times the pitch when the screw makes one rotation, the screwing operation can be performed efficiently.

Furthermore, immediately before the completion of screwing, the female inclined surface 13a formed on the female cylindrical body 7 contacts the male inclined surface 15a formed on the outer peripheral seat 15 of the male cylindrical body 5, and these contact and screw An action of automatically adjusting the misalignment based on the clearance by the pressing force due to the rotation of the rotation occurs.
Hereinafter, this point will be described in detail with reference to FIGS.

FIG. 3A is a vertical cross-sectional view in a state where a part of the female inclined surface 13a and a part of the male inclined surface 15a are in contact with each other immediately before the completion of screwing.
As shown in FIG. 3A, immediately before the completion of screwing, the female inclined surface 13a and the male inclined surface 15a may be displaced in the horizontal direction due to the effect of the clearance provided in the screw portion. At this time, as shown in FIG. 3A, if the male inclined surface 15a on the upper side in the drawing is shifted to the right in the drawing with respect to the female inclined surface 13a, the male inclined surface 15a is in a horizontal state. Since it keeps approaching the female-side inclined surface 13a, the left-side male-side inclined surface 15a and the female-side inclined surface 13a contact each other, but the right-side male-side inclined surface 15a and the female-side inclined surface 13a contact each other. There is no gap.
In this state, when the male cylinder 5 is rotated and the last screwing is performed, the male inclined surface 15a existing on the upper side is guided by the female inclined surface 13a existing on the lower side so that the inclined surface slides. Thus, the state shown in FIG.
In this way, when the screwing is completed, the female side cylinder 7 and the male side cylinder 5 are automatically aligned in a state where the axial centers thereof coincide with each other.

  If the inclination angle α is too small, the effect of guiding the male cylinder 5 when screwing is completed is reduced. Conversely, if the inclination angle α is too large, the function of transmitting the compressive load on the contact surface is impaired. Therefore, since a preferred range of the inclination angle α has been studied, this point will be described below.

FIG. 4 is a graph showing the relationship between the tilt angle, the misalignment correction force, and the load transmission function. The horizontal axis represents the tilt angle α, the left vertical axis represents the misalignment correction force, and the right vertical axis. Indicates the soundness of the load transfer function.
As shown in FIG. 4, the misalignment correction force improves as the inclination angle α increases. On the other hand, when the inclination angle is greater than or equal to a certain value (25 degrees), the soundness of the load transmission function is inhibited.
Therefore, the range of the inclination angle α that can ensure the soundness of the load transmission function while exhibiting the correction force is preferably 5 degrees or more and 25 degrees or less.

An example of the method of joining the steel pipe 1 which comprises a steel pipe pile in a construction site using the joining joint 3 comprised as mentioned above is demonstrated based on FIG.
First, the female cylinder 7 is attached, and the steel pipe 1 with the male cylinder 5 attached to the lower end is suspended by a crane or the like above the steel pipe 1 of the lower pile placed in the ground. 11 is inserted into the female screw of the female cylinder 7. This alignment can be easily performed by the action of the cylindrical portion 11 as described above.

In this state, as shown in FIG. 5, it can be screwed by rotating the upper pile by human power, for example.
Since a certain amount of clearance is provided in the threaded portion of the joint joint 3, misalignment may occur immediately before the completion of screwing, as shown in FIG. When the screwing is completed by the action of the inclined surface 15a, the axial centers of the female cylinder 7 and the male cylinder 5 are automatically adjusted.

Thus, according to the joint joint 3 of the present embodiment, extremely smooth construction can be performed from the alignment at the start of joining, during the screwing, and at the completion of the screwing.
That is, the joint joint 3 of the present embodiment solves a problem that seems to be a trade-off between prevention of misunderstanding and improvement in workability, and is excellent in both load transmission function and workability.

In addition, as an aspect of the female side inclined surface 13a and the male side inclined surface 15a, a flat inclined surface may be provided on the entire front end of the female side cylindrical body 7 as shown in FIG. 6 (b), a part of the front end surface of the female cylinder 7 may be a flat surface and a part may be an inclined surface. Also, as shown in FIG. 6 (c), the inclined surface May be a curved surface.
Moreover, as shown in FIG.6 (d), contrary to what was shown in Fig.6 (a), an inclined surface may become an upward inclination toward a radial outward direction. Needless to say, in the case of the mode shown in FIG. 6D, the same mode as shown in FIGS. 6B and 6C can be adopted.

  Moreover, in said embodiment, although the 4-thread screw was illustrated as an example of a multi-thread screw, this invention is not limited to this, 3 to 8 threads can be applied as the number of threads of a screw. The reason why the upper limit is 8 is that if it exceeds 8, the processing becomes difficult.

[Embodiment 2]
As shown in FIGS. 7 and 8, the joint joint 23 of the present embodiment is axially connected to the distal end portion of the female cylinder 7 and the radially inner side of the inclined surface of the outer peripheral seat 15 of the male cylinder 5. A loose fitting portion 21 to be loosely fitted is formed over the entire circumference.
7 and 8, as an example of the loose fitting portion 21, an annular convex portion 21 a is provided at the distal end portion of the female side cylindrical body 7, and the convex portion 21 a is provided on the outer peripheral seat 15 of the male side cylindrical body 5. A ring-shaped concave groove 21b to be loosely fitted is shown.

  By providing the loose fitting portion 21, a bending force acts on the joined steel pipe piles, and even when the joint joint 23 is curved as shown by the dotted line in FIG. It is possible to prevent the screw 5 from being removed.

  Even when the convex portion 21a and the concave groove 21b are provided, it is essential that the female-side inclined surface 13a and the male-side inclined surface 15a come into contact with each other when the joint joint 23 is screwed in. A gap is formed between the groove 21b as shown in FIG.

  As a specific example of the joint joint of the present invention, for example, SKK490 is used as the material of the steel pipe, and 80 kilo steel is used as the material of the joint joint. Further, the diameter of the steel pipe can be about 400 mm to 1500 mm.

In addition, in order to confirm the effect of preventing misunderstanding due to the provision of the inclined surface in the joint joint, the difference in the screwing completion between the example of the present invention and the case where the inclined surface is not provided and the case where the inclined surface is not provided. investigated.
As a result, when the inclined surface was provided, there was almost no mistake, but when the inclined surface was not provided, a difference of about half of the clearance occurred.

  In the above description, the steel pipe pile is taken as an example of the structure to be placed in the ground. However, the structure targeted by the present invention is not limited to the steel pipe pile. It also includes other structures formed by placing in the ground such as pillars.

1 Steel pipe 3 Joined joint (Embodiment 1)
DESCRIPTION OF SYMBOLS 5 Male side cylinder 7 Female side cylinder 9 Starting end part 11 Cylindrical part 13 Female side front end part 13a Female side inclined surface 15 Outer peripheral seat 15a Male side inclined surface 17 Male side front end part 19 Inner peripheral seat 21 Free fitting part 21a Convex Part 21b Groove 23 Bonded joint (Embodiment 2)

Claims (2)

A steel pipe joint that is attached to an end of a steel pipe constituting a structure to be placed in the ground and joins the steel pipes,
A male side cylinder having a male thread consisting of three or more multi-threaded threads with parallel threads, and a female side cylinder having a female thread consisting of three or more multi-threaded threads with parallel threads;
A cylindrical portion having an outer diameter loosely fitted to the inner diameter of the female screw is provided at the tip of the male side cylinder,
In the state where the male screw of the male cylinder is screwed in and tightened, the tip of the female cylinder is configured to contact an outer peripheral seat formed on the male cylinder,
An inclined surface that is point-symmetric with respect to the center of the cylinder axis and that is inclined in the radial direction is formed over the entire circumference at the tip of the female side cylinder, and the male cylinder that is in contact with the inclined surface The outer peripheral seat is provided with an inclined surface having the same inclination direction and the same inclination angle as the inclined surface over the entire circumference, and the inclination angle with respect to the radial direction of the inclined surface is set in a range of 5 to 25 degrees. Steel pipe joint.   A free fitting portion that loosely fits in the axial direction is formed over the entire circumference on the radially inner side of the inclined surface of the distal end portion of the female side cylindrical body and the outer peripheral seat of the male side cylindrical body. The steel pipe joint according to claim 1.