JP2001153115A - Steel pipe connecting structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a steel pipe connecting structure which can simplify a steel pipe manufacturing or assembling process and can reduce a manufacturing cost. SOLUTION: In the steel pipe connecting structure, steel pipes are connected to each other in a manner that an annular projection is forcibly inserted into an annular groove by the elasticity of the steel pipe itself and the female part of the steel pipe is fitted around the male part thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a steel pipe connecting structure.

[0002]

In tunnel excavation and the like, it has been known to implement a long end receiving method or a pipe roof method, which is an example of an earth retaining method, in order to prevent collapse of a fragile ground in front of and above a face. I have. In these construction methods, a method of arranging a short divided steel pipe to a predetermined depth while connecting the steel pipes is widely known.

As a conventional steel pipe connection structure, for example,
As shown in FIG. 6, a female part a and a male part b are provided at the ends of the steel pipes to be connected, and a male part b is provided in a concave part a1 of the female part a.
Of the male part b and the female part a in the concave part b1 of the male part b.
And a structure in which the projections a2 are matched and connected.

However, when the male part b is press-fitted into the female part a, the diameter of the male part b is reduced.
In which a plurality of slits b3 are formed in the axial direction. However, such processing of the slit b3 complicates the manufacturing process of the steel pipe and causes a high cost. Further, there is a structure in which a threaded joint is provided in the male part and the female part, but this increases the cost and requires time and labor for the connecting operation.

FIG. 7 shows the tip of a known double-pipe drilling tool for drilling ground, rock, and the like. This tool attaches a ring bit c to the tip of an outer tube a via a top joint b, attaches an inner bit e to a tip of an inner tube d arranged in the outer tube a, and adjusts the rotational force of the inner tube d. The excavation is performed by transmitting the impact force to the inner bit e and the ring bit c. After excavation to a predetermined depth, the inner pipe d is pulled out together with the inner bit e, and the ring bit c, the top joint b, and the outer pipe d are left underground.

Here, since the ring bit c rotates together with the inner bit e, the fixed top joint b
Must be connected so that they can rotate. The striking force of the inner pipe d is transmitted to the ring bit c by the striking surface e2 of the striking portion e1 of the inner bit e striking the end face b1 of the top joint b. Accordingly, the impact force at that time causes wear on the end face b1 of the top joint b. And since it is necessary to advance the inner bit e and the ring bit c by the amount of wear,
The ring bit c needs to be configured to be slidable in the axial direction with respect to the top joint b.

Conventionally, therefore, the ring bit c and the top joint b are mounted in a rotatable loose fit state, and are inserted into the gap f surrounded by the annular grooves b2 and c1 provided at the opposing positions. The iron wheel g is inserted from the insertion hole b3 all around. This prevents the ring bit c from being pulled out of the top joint b. Then, the axial length of the gap f is longer than the cross-sectional dimension of the iron ring g,
The ring bit c is configured to be slidable in the axial direction.

However, the method using the iron wheel g as described above increases the number of parts and increases the cost, and also increases the cost.
Insertion work is complicated, which causes a reduction in the efficiency of the work of assembling the double pipe.

[0009]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its object to simplify a steel pipe manufacturing process or an assembling process and to reduce the manufacturing cost. Is provided.

[0010]

According to the present invention, as a means for solving the above problems, a steel pipe is provided at a connecting end of one steel pipe in a female section provided at a connecting end of the other steel pipe. In the structure in which the male portion is fitted to connect the steel pipes, the female portion gradually expands the inner peripheral surface from the base end to the distal end to form the expanded portion, An annular groove is formed in the circumferential direction adjacent to the proximal end of the inner peripheral surface of the portion, and the male portion gradually reduces the outer peripheral surface from the proximal end toward the distal end, and the enlarged portion and Along with forming the reduced diameter portion so as to match, adjacent to the distal end side of the outer peripheral surface of the reduced diameter portion, an annular projection matching the inside of the annular groove is formed in the circumferential direction,
The outer diameter of this annular projection is provided without an axial slit for expanding or reducing the tube diameter in the female or male part,
Due to the elasticity of the steel pipe material itself, it is formed slightly larger than the minimum inner diameter portion of the enlarged diameter portion so that it can be pressed into the annular groove and does not pull out, and the enlarged diameter portion and the reduced diameter portion, the annular groove and the annular shape are formed. Provided is a steel pipe connection structure, wherein the steel pipes are connected by matching the projections and fitting the female part and the male part.

According to a second aspect of the present invention, in the structure for connecting a steel pipe by fitting a male part provided at a connection end of the other steel pipe into a female part provided at a connection end of one steel pipe, the male part is connected to the female part. The diameter of the outer peripheral surface is gradually reduced from the base end toward the distal end to form a reduced diameter portion, and an annular groove is formed in the circumferential direction adjacent to the base end side of the outer peripheral surface of the reduced diameter portion. The scalpel portion gradually expands the inner peripheral surface from the base end portion to the distal end portion, forms an enlarged diameter portion so as to match the reduced diameter portion, and forms an inner peripheral surface of the enlarged diameter portion. An annular projection that fits inside the annular groove is formed in the circumferential direction so as to be adjacent to the distal end side of the groove, and the inner diameter of the annular projection is provided with an axial slit for expanding or contracting the pipe diameter in the female portion or the male portion. Without being pressed into the annular groove by the elasticity of the steel pipe material itself and without being pulled out. The steel pipe is connected by forming it slightly smaller than the maximum outer diameter part of the reduced diameter part, matching the enlarged diameter part with the reduced diameter part, the annular groove and the annular protrusion, and fitting the female part and the male part. Characterized in that it is configured to
Provide a steel pipe connection structure.

According to a third aspect of the present invention, there is provided a structure for connecting a steel pipe by fitting a male part provided at a connection end of the other steel pipe into a female part provided at a connection end of one steel pipe. An annular projection is formed in the circumferential direction on the inner peripheral surface of the male part, an annular groove is formed in the circumferential direction adjacent to the proximal end side of the female part of the annular projection, and the annular projection of the female part is formed on the outer peripheral surface of the male part. Is formed in the circumferential direction, and an annular protrusion fitted in the annular groove of the female part is formed in the circumferential direction adjacent to the distal end side of the male part of the annular groove. The outer diameter of the annular projection can be press-fitted into the annular groove of the female part by the elasticity of the steel pipe material itself without providing an axial slit in the female part or the male part for expanding and contracting the pipe diameter. So that it is slightly larger than the inner diameter of the annular projection of the female part, and The annular protrusions of the female part and the male part are formed to have dimensions that are rotatable and slidable in the axial direction of the steel pipe in a state fitted in the annular grooves of the female part and the male part. A steel pipe connecting structure, wherein the steel pipe is connected by fitting the annular projection with the annular pipe. Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0013]

First Embodiment As shown in FIGS. 1 and 2, a female part 100 is provided at a connecting end of one steel pipe, and a male part 200 fitted to the female part 100 is provided at a connecting end of the other steel pipe. Is provided.

The scalpel portion 100 forms an enlarged diameter portion 110 by gradually increasing the diameter of the inner peripheral surface from the base end portion to the distal end portion, and is formed on the proximal end side of the inner peripheral surface of the enlarged diameter portion 110. An annular groove 120 is formed in the circumferential direction so as to be adjacent. In addition, an equal-diameter portion 111 having the same inner diameter is provided at the base end and the front end of the inner peripheral surface of the enlarged diameter portion 110.
And 112 may be formed.

The male part 200 gradually reduces the diameter of the outer peripheral surface from the base end part to the distal end part, and forms a reduced diameter part 210 so as to match the enlarged diameter part 110 of the female part 100, and also forms this reduced diameter part. Diameter 2
An annular projection 220 is formed in the circumferential direction adjacent to the distal end side of the outer peripheral surface of 10 so as to fit in the annular groove 120 of the female part 100. In addition, the base end and the distal end of the outer peripheral surface of the reduced diameter portion 210 are formed with equal diameter portions 211 and 212 having the same outer diameter, which match the equal diameter portions 111 and 112 of the female portion 100. Is also good. Further, a tapered portion 221 may be provided at the tip of the outer peripheral surface of the annular protrusion 220 to facilitate insertion into the female portion 100.

The outer diameter of the annular projection 220 can be adjusted by the elasticity of the steel tube material itself without providing an axial slit in the female portion 100 or the male portion 200 for expanding or reducing the pipe diameter. In order to be able to press-fit into 120 and not to be pulled out, the minimum inner diameter portion of the enlarged diameter portion 110 of the female portion 100,
It is formed slightly larger than the inside diameter of 111.

Then, as shown in FIG. 2, the male part 200 is press-fitted into the female part 100, the annular groove 120 and the annular projection 220, the enlarged diameter part 110 and the reduced diameter part 210, the equal diameter parts 211 and 112, etc. Both steel pipes can be connected by matching the diameter portions 212 and 111 and fitting the female portion 100 and the male portion 200, respectively.

[0018]

[Embodiment 2] FIG. 3 shows a case where the female part and the male part are reverse to those of the first embodiment. That is, the female part 300
Are, in order from the base end, an equal diameter portion 310, an enlarged diameter portion 320, and an equal diameter portion 33.
0, an annular projection 340, a tapered portion 350, the male portion 400,
In order from the base end, an annular groove 410, an equal diameter portion 420, a reduced diameter portion 430,
It consists of an equal diameter part 440.

[0019]

Third Embodiment FIG. 4 shows a case where both a female part and a male part are provided with an annular groove and an annular projection. That is, the female part 50
0 is an annular groove 510, an equal diameter portion 520, and an enlarged diameter portion 5 in order from the base end.
30, consisting of an equal diameter part 540, an annular protrusion 550, and a tapered part 560,
The male part 600 has an annular groove 610 and an equal diameter part 62 in order from the base end.
0, reduced diameter part 630, equal diameter part 640, annular projection 650, tapered part 660
Consists of By providing the annular groove and the annular projection on both the female part and the male part in this way, the pull-out resistance of the tube body is increased, and the connection can be made stronger.

[0020]

[Embodiment 4] FIG. 5 shows an embodiment of a structure for connecting a pipe so as to be rotatable and slidable in an axial direction, and a top joint b constituting a tip portion of a double pipe type drilling tool.
The connection structure of the ring bit c and the ring bit c will be described as an example.

The top joint b is a member for attaching a ring bit c to the tip of the outer tube a. A first annular groove 710, an annular protrusion 720, and a second annular groove 730 are formed in the circumferential direction on the inner peripheral surface of the female portion 700 at the connection end of the top joint b in order from the base end. The second annular groove 730 is the first annular groove
Formed slightly larger than 710 in diameter.

On the outer peripheral surface of the male portion 800 at the connection end of the ring bit c, a first annular groove 810, a second annular groove 820 having a slightly smaller diameter, an annular protrusion 830, and a tapered portion 84 are arranged in order from the base end.
0 is formed in the circumferential direction. And the annular projection 83 of the male part 800
The outer diameter of 0 can be press-fitted into the first annular groove 710 of the female part 700 by the elasticity of the steel pipe material itself without providing an axial slit for expanding or reducing the pipe diameter in the female part 700 or the male part 800. So that it is slightly larger than the inner diameter of the annular projection 720 of the female part 700 so as not to be pulled out.

Further, the annular projections 720 and 830 of the female part 700 and the male part 800 are formed by the first annular groove 71 of the female part 700 and the male part 800.
It is formed so as to be rotatable while fitted in the second annular groove 820 and to be slidable in the axial direction of the steel pipe. That is,
The first annular groove is longer than the axial length of the annular projections 720 and 830.
The length in the axial direction of 710 and the second annular groove 820 is set to be sufficiently long, and the sliding in the axial direction is enabled. Further, the first annular groove 810 and the second annular groove 730, the annular protrusion 720 and the second annular groove 820,
A small gap is set between the inner and outer peripheral surfaces of the annular projection 830 and the first annular groove 710 to enable the rotation of the ring bit c.

Then, the annular projection 830 of the male part 800 is connected to the female part.
By press-fitting and fitting into the first annular groove 710 of the 700, the top joint b and the ring bit c can be connected rotatably and slidably in the axial direction.

Although not shown, the second annular groove 730 of the female part 700 and the first annular groove 810 of the male part 800 may not be provided. In addition, contrary to the fourth embodiment, the first annular groove, the second annular groove, the annular protrusion, and the tapered portion are formed in order from the base end of the inner peripheral surface of the female portion, and the base end of the inner peripheral surface of the male portion is formed. The first annular groove, the annular protrusion, and the second annular groove may be formed in this order.

[0026]

Since the present invention is configured as described above,
The following effects can be obtained. <B> The annular projection is press-fitted into the annular groove by the elasticity of the steel pipe material itself. Therefore, there is no need to provide a conventional slit at the connection end of the steel pipe. Therefore, it is possible to simplify the manufacturing process of the steel pipe and reduce the cost.

<B> When connecting a steel pipe such as a ring bit and a top joint of a double pipe type excavating tool, it is not necessary to provide a slit at the connection end of the steel pipe as described above. The process can be simplified and the cost can be reduced, and the steel pipes can be connected rotatably and slidably in the axial direction without using a conventional iron wheel. Therefore, it is possible to reduce the number of parts and cost, and to simplify the assembly process of the steel pipe.

[Brief description of the drawings]

FIG. 1 is a perspective view of a first embodiment of the present invention.

FIG. 2 is an enlarged sectional view of a main part according to the first embodiment of the present invention;

FIG. 3 is an enlarged sectional view of a main part according to a second embodiment of the present invention.

FIG. 4 is an enlarged sectional view of a main part according to a third embodiment of the present invention.

FIG. 5 is an enlarged sectional view of a main part according to a fourth embodiment of the present invention.

FIG. 6 is an explanatory view of a conventional technique.

FIG. 7 is an explanatory diagram of a conventional technique.

Claims (3)

[Claims] 1. A structure for connecting a steel pipe by fitting a male part provided at a connection end of another steel pipe into a female part provided at a connection end of one steel pipe, wherein the female part is The inner peripheral surface is gradually increased in diameter from the end to the distal end to form an enlarged diameter portion, and an annular groove is formed in the circumferential direction adjacent to the base end side of the inner peripheral surface of the enlarged diameter portion. The male portion gradually reduces the outer peripheral surface from the base end portion to the distal end portion, forms a reduced diameter portion so as to match the enlarged diameter portion, and forms a distal end side of the outer peripheral surface of the reduced diameter portion. An annular projection matching the inside of the annular groove is formed in the circumferential direction adjacent to the annular groove, and the outer diameter of the annular projection does not need to be provided in the female portion or the male portion with an axial slit for expanding and contracting the tube diameter. ,
Formed slightly larger than the minimum inner diameter portion of the enlarged diameter portion so that it can be pressed into the annular groove and cannot be pulled out by the elasticity of the steel pipe material itself, the enlarged diameter portion and the reduced diameter portion, the annular groove and the annular shape. A steel pipe connecting structure, wherein the steel pipes are connected by matching the projections and fitting the female part and the male part. 2. A structure for connecting a steel pipe by fitting a male part provided at a connecting end of another steel pipe into a female part provided at a connecting end of one steel pipe, wherein the male part is The outer peripheral surface is gradually reduced in diameter from the end toward the distal end to form a reduced diameter portion, and an annular groove is formed in the circumferential direction adjacent to the base end side of the outer peripheral surface of the reduced diameter portion. The scalpel portion gradually expands the inner peripheral surface from the base end portion to the distal end portion, forms a large-diameter portion so as to match the reduced-diameter portion, and forms a distal end side of the inner peripheral surface of the large-diameter portion. An annular projection matching the inside of the annular groove is formed in the circumferential direction adjacent to the annular groove, and the inner diameter of the annular projection is provided without providing an axial slit for expanding or reducing the pipe diameter in the female part or the male part,
Due to the elasticity of the steel pipe material itself, it can be press-fitted into the annular groove and cannot be pulled out, so that it is formed slightly smaller than the maximum outer diameter portion of the reduced diameter portion. A steel pipe connection structure, wherein a steel pipe is connected by matching an annular projection and fitting the female part and the male part. 3. A structure for connecting a steel pipe by fitting a male part provided at a connection end of the other steel pipe into a female part provided at a connection end of one steel pipe, wherein the inner circumference of the female part is provided. An annular protrusion is formed in the circumferential direction on the surface, an annular groove is formed in the circumferential direction adjacent to the base end side of the female portion of the annular protrusion, and the annular protrusion of the female portion fits on the outer peripheral surface of the male portion. An annular groove is formed in the circumferential direction, and an annular protrusion that fits in the annular groove of the female portion is formed in the circumferential direction adjacent to the distal end side of the male portion of the annular groove. The outer diameter can be press-fitted into the annular groove of the female part without being pulled out by the elasticity of the steel pipe material itself without providing an axial slit for expanding and contracting the pipe diameter in the female part or the male part. A slightly larger inner diameter of the annular projection of the female part; The annular protrusion of the female part is formed to have a dimension that is rotatable in a state fitted into the annular groove of the female part and the male part and is slidable in the axial direction of the steel pipe. A steel pipe connection structure, characterized in that the steel pipes are connected by fitting them together.