JPH09137446A - Screw joint structure of steel pipe pile or the like - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate the screwing-in work, by providing parallel screws and taper screws respectively at male and female screw joints so that the parallel screws begin to mesh with each other prior to the taper screws. SOLUTION: The first steel pipe pile body provided with a female screw joint at the upper end is buried in the ground. And the second steel pipe pile body provided with a male screw joint at the lower end is hoisted up by a crane car. Then the second steel pipe pile body is lowered to position the male screw joint 1 at the upper side of the female screw joint 4 of the first steel pipe pile body and insert the male screw joint into the female screw joint. In this way, the parallel male screw part 3a is arranged to contact the parallel female screw part 3b prior to the taper male screw part 2a. And further, when the second steel pipe pile body is rotated, the male screw joint 1 advances to the axial direction of the pipe of the female screw joint 4 in accordance with the screw pitch of the parallel male screw part 3a and the taper male screw part 2a is screwed in the taper female screw part 2b.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a threaded joint structure such as a steel pipe pile, and more particularly, to a pile, a steel pipe pile, and a steel pipe sheet pile (hereinafter collectively referred to as a steel pipe pile) jointed by a joint having a threaded portion. And the like) can be easily and surely joined.

[0002]

2. Description of the Related Art In the field joint pile work performed to prevent landslides and the like, instead of the conventional field welding, a field joint pile using a screw joint is performed as a simple joint. FIG. 8 is a schematic view showing an example of a joint structure of a conventional steel pipe pile for landslide prevention disclosed in JP-A-7-82738 (Prior art example 1). The male and female threaded joints 1 and 4 provided at the ends of the steel pipe pile main body are provided with taper male threaded portions and taper female threaded portions 2a and 2b, respectively, and the taper male threaded portion 2a is inserted into the taper female threaded portion 2b, and then rotated several times (substantially). The screwing is completed in 3 to 5 rotations. In Japanese Patent Laid-Open No. 7-102555, the taper male and female screw portions 2a and 2b of Conventional Example 1 are numerically limited with respect to the taper angle, thread pitch, etc. (Conventional Example 2).

FIG. 9 is a schematic view showing another example of a steel pipe pile with a threaded joint (conventional example 3). The male and female threaded joints 1 and 4 provided at the ends of the steel pipe pile main body are provided with parallel male threaded portions and parallel female threaded portions 3a and 3b, respectively. Since they mesh smoothly as they are, this point is superior to the threaded joint portions of Conventional Examples 1 and 2, but on the other hand, the joining requires the rotation of the number of screw threads. For example, the size of the steel pipe pile body has an outer diameter of 3
Assuming that the threaded joint portions 3a and 3b of the steel pipe pile main body have a thread count of 30 threads with a thickness of 18.5 mm and a wall thickness of 35 mm, the threaded joint requires 30 rotations, and the screwing is completed in 3 to 5 rotations. It cannot be said that the workability is good as compared with Conventional Example 1 (FIG. 8).

When these first to third conventional examples are further compared, the screw joint portion having the tapered male and female screw portions 2a and 2b as in the conventional example 1 (FIG. 8) has a screw at the tip portion. Unlike a parallel screw like the conventional example 3 (FIG. 9) that sequentially engages from the crest, the male screw joint part 1 is inserted into the female screw joint part 4 until the middle of the connection, and after the screw crests come into contact with each other,
The screw-in rotation is started and all threads are engaged at the same time. That is, regardless of the length of the threaded portion, the amount of rotation required for joining is determined by screw thread height × taper / screw pitch, and screwing is completed with a much smaller amount of rotation than parallel threads.

On the other hand, in order to smoothly join the taper male and female threaded portions 2a and 2b as in the conventional example 1, the upper and lower steel pipe pile main bodies having the male and female threaded joints 1 and 4 are securely aligned. There must be. If the axes of the steel pipe pile main bodies having the male and female threaded joints 1 and 4 are not aligned, the threads will be bitten during the screwing, making it impossible to screw in. Further, in the screwing operation, it is necessary to advance the steel pipe pile main body having the threaded joint portion in the axial direction according to the thread pitch. On the other hand, the parallel male and female threaded portions 3a and 3b shown in the conventional example 3 can be screwed in by applying a large torque without moving in the tube axis direction. , Female screw portions 2a, 2b
In the case of 1, in the initial stage until the threads are meshed with each other, unless the movement adjustment in the pipe axis direction according to the thread pitch is properly performed, galling of the threads occurs.

FIG. 10 shows, for example, Japanese Patent Laid-Open No. 7-81796.
It is a schematic diagram which shows an example of the conventional steel pipe pile with a screw joint disclosed by the gazette (conventional example 4), and the discontinuity screw which provided the step in a parallel male and female thread part with respect to the conventional example 3 (FIG. 9). age,
The threads of opposite steps mesh with each other at the same time,
The joining is completed by the number of threads / the number of steps. That is, the male and female threaded joints 1 and 4 provided at the ends of the steel pipe pile body are provided with the first and second parallel male threaded portions 3
c, 3d and first and second parallel female screw portions 3e, 3f are provided. The diameter of each threaded portion changes discontinuously over two steps (or a large number of steps). Due to this step, the first and second threads are meshed at the same time, and the screwing rotation amount is small. Has become.

For example, the size of the steel pipe pile body has an outer diameter of 31.
If the number of threads in the threaded joint portion of the steel pipe pile body is 8.5 mm, the wall thickness is 35 mm, and the number of threads is 30, it is necessary to rotate 10 times or more even if a three-stage screw is used, and welding is performed in 3 to 5 rotations. It cannot be said that the workability is good as compared with the completed conventional example 1 (FIG. 8).

FIG. 11 is a schematic view showing an example of a conventional joint structure of a steel pipe pile having a threaded portion (conventional example 5).
The tapered male and female threaded portions 2a and 2b shown in FIG. 8 are provided with insertion portions to provide a centering function. That is, a male insertion portion 13a, which is a non-threaded portion, is provided at the tip of the male threaded joint portion 1 that connects the steel pipe pile body, and a female insertion portion 13b, which is a non-threaded portion, is provided at the position of the female threaded joint portion 4 corresponding to this. Is provided to serve as a guide for joining the joints. When the male and female insertion portions 13a and 13b provided on the male and female screw joint portions 1 and 4 are fitted in advance, the male screw joint portion 1 and the female screw joint portion 4 have their axial centers aligned with each other, and the male and female screw threads are opposed to each other. The joints 1 and 4 rotate on concentric circles, which makes screwing in smoother.

[0009]

According to the threaded joint structure of the conventional example 5 (FIG. 11) configured as described above, the male and female insertion portions 13a and 13b are used for centering, but while rotating. It does not have the function of proceeding in the axial direction. That is, when the steel pipe piles having the male and female threaded joint portions 1 and 4 are connected, first of all, the opposing male and female insertion portions 13 are connected.
As shown in FIG. 12, as shown in FIG. 12, the male,
The threads 2c and 2d of the female threaded joints 1 and 4 come into contact with each other,
There are cases where screwing becomes impossible.

The present invention has been made in order to solve the above problems, and a steel pipe pile or the like which can be easily and reliably screwed and joined without finely controlling the alignment and the slight drop. The purpose is to obtain a threaded joint structure.

[0011]

A threaded joint structure for a steel pipe pile or the like according to the present invention is constructed as follows. (1) A screw joint structure for joining pile ends of a plurality of steel pipe piles, etc. at a construction site, wherein a male screw joint portion and a female screw joint portion are provided at the end portions of the steel pipe pile, and these screw joint portions are provided. Is provided with a threaded portion including a taper threaded portion and a parallel threaded portion. The parallel threads of the male and female threaded joints start meshing prior to the taper threaded portion to start the alignment of the male and female threaded joints. Engage with prevention.

(2) In the threaded joint structure of (1) above, the parallel thread portion is provided at the base portion or the tip portion of the taper thread portion. After the parallel threaded portions near the base of the male and female joints start meshing prior to the taper screwed portion to align the male and female joints and perform the guide function, the tapered threaded portions are Engage while preventing galling of the threads.

(3) In the threaded joint structure of (1) or (2) above, n is the number of threads required for the parallel threads, h is the thread height, k is the taper angle, and p is the thread pitch. At this time, the relationship of n ≧ hk / p is satisfied. The parallel threaded portions satisfying the relation of n ≧ hk / p of the male and female joints started meshing prior to the taper screwed portion to align the male and female joints and perform the guide function. After that, the taper threads engage with each other while preventing the thread from galling.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 FIG. 1 is a schematic diagram of the first embodiment of the present invention. Reference numeral 1 denotes a male threaded joint portion having a convex tip portion, which is attached to an end portion of a steel pipe pile body (not shown) used for slip prevention, for example, by welding or the like, and the outer diameter of the attachment portion is a steel pipe pile. It is formed to have almost the same outer diameter as the main body. Reference numeral 2a denotes a taper male screw portion provided at a tip portion (lower end portion in the drawing) of the male screw joint portion 1, which is formed in a taper shape having a diameter reduced toward the tip portion (downward direction in the diagram), and a taper female screw portion of the female screw joint portion. (See below)
It has an inclined surface and a screw thread interval where screwing is completed in a few turns.

Reference numeral 3a designates a parallel male screw portion provided on the male screw joint portion 1, which is provided on the base portion (end portion) of the taper male screw portion 2a, that is, on the large diameter side, and has a larger thread diameter than the outer diameter on the large diameter side. Formed, and has the same thread interval as the taper male screw portion 2a. Since the number of threads provided on the parallel male screw portion 3a is directly linked to the number of rotations, the smaller the number, the better the workability, but the number of threads required to guide the threads of the tapered male screw portion 2a until they mesh with each other. Must have. Therefore, the parallel male screw portion 3a
In order to reliably perform the function as a guide, it is preferable to guide the taper male threaded portion 2a by the parallel male threaded portion 3a until half or more of the threads are engaged. Therefore, the number of threads required for the parallel male screw portion 3a is n ≧ hk / p, where n is the required number of threads, h is the thread height, k is the taper angle, and p is the thread pitch.

Reference numeral 4 denotes a female threaded joint portion having a concave tip for joining with the convex male threaded joint portion 1, which is attached to the end portion of the steel pipe pile body (not shown) by welding or the like. The outer diameter of is approximately the same as the outer diameter of the steel pipe pile body. 2b is provided on the upper part of the female screw joint portion 4,
It is a concave taper female screw portion with which the taper male screw portion 2a is screwed, and is formed in a taper shape by expanding the diameter toward the inlet side (upper direction in the figure), and the screwing is completed by rotating the taper male screw portion 2a several times. The taper surface and the thread groove spacing are provided. Reference numeral 3b denotes a parallel female screw portion that is screwed with the parallel male screw portion 3a, and is provided on the inlet side of the taper female screw portion 2b, that is, on the large diameter side, and has a larger thread groove diameter than the outer diameter of the taper female screw portion 2b on the large diameter side. The taper female threaded portion 2b has the same thread groove spacing.

In the male screw joint portion 1 and the female screw joint portion 4, the male screw joint portion 1 is replaced with the female screw joint portion 2.
At this time, the parallel male threaded portion 2a of the male threaded joint portion 1 precedes the tapered male threaded portion 2a at the time of connection of the joint and starts to mesh with the parallel female threaded portion 3b of the female threaded joint portion 4, which is guided. Thus, the taper male screw portion 2a and the taper female screw portion 2b are meshed with each other through the aligning action, and the thread ridges of these taper male and female screw portions 2a and 2b are prevented from being galled, so that they are screwed together. ing. The male threaded joint portion 1 and the female threaded joint portion 4 may be provided with a material strength greater than that of the steel pipe pile body or a screw end portion thickness greater than that of the steel pipe pile body.

The operation of the present embodiment configured as described above will be described with reference to FIG. First, the female threaded joint 4 is attached to the upper end.
The first steel pipe pile main body 5 provided with is embedded in the ground 7 by the crane vehicle 6, and then the second with the male screw joint portion 1 provided at the lower end portion.
The steel pipe pile main body 8 is suspended by the crane vehicle 6. And
The second steel pipe pile main body 8 is lowered so that the male screw joint portion 1 is located above the female screw joint portion 4 of the first steel pipe pile main body 5.

Next, the second steel pipe pile main body 8 is lowered to connect the male screw joint portion 1 to the female screw joint portion 4 of the first steel pipe pile body 5.
1, the parallel male threaded portion 3a shown in FIG. 1 comes into contact with the parallel female threaded portion 3b prior to the tapered male threaded portion 2a, and this serves as a guide to perform the centering action. Next, when the second steel pipe pile main body 8 is rotated, screwing is started, and the male screw joint portion 1 advances in the pipe axial direction of the female screw joint portion 4 in accordance with the thread pitch of the parallel male screw portion 3a. Then, as shown in FIG. 3, the threads of the taper male thread portion 2a do not bite the threads of the taper female thread portion 2b in the middle, and
As c and 2d mesh smoothly, and the second steel pipe pile main body 8 rotates, the taper male screw portion 2a is screwed into the taper female screw portion 2b, and the screwing operation is completed.

In the past, since the taper screw portion itself was easily gazed during screwing, it was troublesome to perform the centering work and the slight descending action surely, but according to this embodiment, the parallel male and female screw portions 3a are formed. , 3b having the function of guiding the start of biting of the taper male and female screw portions 2a, 2b, the centering work is also carried out, and the screw threads 2c, 2d are also required without performing a slight descending work. There is no biting.

Embodiment 2 FIG. 4 is a schematic view of the second embodiment of the present invention. In the first embodiment, the parallel male threaded portion 3a of the male threaded joint portion 1 is provided at the base of the tapered male threaded portion 2a, but in the present embodiment, the parallel threaded portion 3a is provided at the tip of the tapered male threaded portion 2a. 4 corresponds to this. Reference numeral 3a is a parallel male screw portion provided at the tip of the tapered male screw portion 2a of the male screw joint portion 1, and the thread diameter thereof is the tapered male screw portion 2a.
Is formed to have a diameter smaller than the outer diameter of the tip end portion of the. Further, 3b is a parallel female screw portion 3b which is provided at the innermost portion of the tapered female screw portion 2b of the female screw joint portion 4 and into which the parallel male screw portion 3a is fitted and screwed. Then, the parallel male threaded portion 3a of the male threaded joint portion 1 first meshes with the parallel female threaded portion 3b of the female threaded joint portion 4, and this serves as a guide to cause the centering action. The operation and effect of the present embodiment configured as described above are substantially the same as the case shown in the first embodiment, and therefore description thereof will be omitted.

[0022]

EXAMPLE In the invention shown in the first embodiment, in order to confirm the workability, a construction test was conducted using full-scale male and female joints. As shown in FIG. 5, a steel pipe is provided with a male threaded joint portion 1 to form a steel pipe upper pile 8, which is a crane truck 6
It was hung at and screwed to the female threaded joint portion 4.
At this time, the size of the steel pipe upper pile 8 has an outer diameter of 318.5 m.
m, wall thickness 35 mm, and length 6 m. Further, as shown in FIG. 6, the female threaded joint portion 4 is welded onto the upper steel plate 9, and further, by using the steel pipe 10 and the lower steel plate 11, the ground pipe 1 to 1.
Steel pipe lower pile 5 installed at the position of 5m and inserted in the ground
It was likened to. These male and female threaded joints 1 and 4 have a maximum plate thickness of 42 mm, a taper thread length of 160 mm, a thread pitch of 1 inch / 3 threads, and a thread height of 3 mm.
Further, the height of the parallel male and female screw portions 3a and 3b provided at the root portions of the taper screw joint portions 1 and 4 was 50 mm.

In this way, the male screw joint portion 1 of the steel pipe upper pile 8 is inserted into the female screw joint portion 4 of the steel pipe lower pile 5, and the parallel male screw portion 3 is inserted.
After a first contacted the parallel female screw portion 3b, the screwing rotation was started. At this time, taper male and female thread 2
The screw threads of a and 2b did not bite each other, and the screwing operation was completed smoothly at 6.5 rotations. This experiment was performed twice and the parallel screwing time was 4 minutes.

In order to confirm the aligning function, as shown in FIG. 7, a steel piece 12 is inserted into one side of the female threaded joint portion 4 and the taper female threaded portion 4, that is, the steel pipe lower pile 5a is ⅙.
The screwing construction test was performed with the inclination of. After manually pushing the lower end of the steel pipe upper pile 8 to perform centering visually,
When the screwing operation was performed in the same manner as the above, it was possible to screw in smoothly, and the work was completed in about 6 minutes.

[0025]

According to the present invention, there is provided a threaded joint structure for jointing pile ends of a plurality of steel pipe piles at a construction site,
A male threaded joint and a female threaded joint are provided at the ends of steel pipe piles, etc., and a threaded section consisting of a tapered threaded section and a parallel threaded section is provided at each of these threaded joints, and the parallel threaded section precedes the tapered threaded section. Since it was configured to start meshing with
It was possible to easily and surely perform the screwing and joining work without finely controlling the alignment and the slight drop, and it was possible to greatly improve the work efficiency.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a first embodiment of the present invention.

FIG. 2 is an operation explanatory view of FIG. 1;

FIG. 3 is an explanatory view of the operation of FIG.

FIG. 4 is a schematic diagram of a second embodiment of the present invention.

FIG. 5 is an explanatory view of the operation of the embodiment of the present invention.

FIG. 6 is a side view of a main part of FIG. 5;

FIG. 7 is an explanatory view of the operation of the embodiment of the present invention.

FIG. 8 is a schematic view showing an example of a conventional threaded joint structure.

FIG. 9 is a schematic view showing an example of another conventional threaded joint structure.

FIG. 10 is a schematic view showing an example of still another conventional threaded joint structure.

FIG. 11 is a schematic view showing an example of another conventional threaded joint structure.

FIG. 12 is an operation explanatory view of FIG. 11;

[Explanation of symbols]

 1 Male screw joint part 2a, 2b Tapered screw part 3a, 3b Parallel screw part 4 Female screw joint part 5 1st steel pipe pile main body 8 2nd steel pipe pile main body

Claims (3)

[Claims] 1. A screw joint structure for joining pile ends of a plurality of steel pipe piles, etc. at a construction site, wherein a male screw joint portion and a female screw joint portion are provided at the end portions of the steel pipe piles, and these screw joints are provided. A threaded joint structure for a steel pipe pile or the like, characterized in that a threaded portion including a taper threaded portion and a parallel threaded portion is provided in the portion, and the parallel threaded portion starts meshing prior to the taper threaded portion. 2. The threaded joint structure for a steel pipe pile or the like according to claim 1, wherein the parallel thread portion is provided at a base portion or a tip portion of the taper thread portion. 3. When n is the number of threads required for a parallel thread portion, h is the thread height, k is the taper angle, and p is the thread pitch, the relationship n ≧ hk / p is satisfied. The threaded joint structure for a steel pipe pile or the like according to claim 1 or 2.