JP7297251B2 - Underground drilling pipe using high-strength thin-walled steel pipe - Google Patents

Description

The present invention is an underground drilling pipe used for drilling work in the ground. A long inner rod is arranged inside the drilling outer pipe by connecting multiple relay rods with a sleeve, and an inner bit is attached to the lower end of the inner rod. It is widely used in civil engineering work where the inner bit and ring bit are simultaneously rotated by the rotation of the inner rod, and the ground and rock are drilled. A protection tube for protecting the taper threaded portion of the uppermost high-strength thin-walled steel pipe when using a known underground drilling pipe, particularly a light-weight, high-strength, and durable high-strength thin-walled steel pipe. It relates to an improved technology that can solve the difficulty of desorption of the.

Conventionally, the drilling outer pipe of the underground drilling pipe used in devices such as rock drills and drilling machines for underground piles has male and female threads opposite to each other at the upper and lower ends as shown in Patent Document 1. A plurality of steel pipes formed with are screwed together at the upper and lower ends to make them long so that they can correspond to the depth of drilling.
The threaded portion of the male thread at the upper end of the uppermost steel pipe of the drilled outer pipe is used while being exposed. As a result, during drilling work, the exposed screw portion comes into contact with other machines, instruments, members, etc., and the screw portion is deformed, displaced, or damaged, making it impossible to screw it with other steel pipes. . In order to avoid this, a hollow cylindrical protective tube is screwed onto the exposed threaded portion of the upper end of the uppermost steel pipe so that the exposed threaded portion does not come into contact with other members, etc., to prevent deformation, displacement, and damage. was preventing

In the case of a conventional drilled outer pipe using a conventional steel pipe with a wall thickness of about 6 mm, which does not use a high-strength thin-walled steel pipe, a straight thread can be used for the threaded portion of the steel pipe, and the protective pipe having the same straight thread is used to the end. Even if it is tightened, it can be sufficiently tightened and removed easily by human power, and there was no problem in attaching and removing it.
However, in the case of screwing the straight screw, there is a problem that the protection tube comes off due to vibration or the like.

The use of a high-strength, thin-walled steel pipe with a wall thickness of about 3.5 mm, which has high strength and durability, is advantageous in light weight, high strength, and improved durability. However, high-strength thin-walled steel pipes employ tapered threads at the upper and lower ends, and as shown in FIG. When this protective tube is screwed to the end of the tapered thread at the upper end of the high-strength thin steel tube, it cannot be removed manually. In addition, even if the screw portion is partially tightened, the screw may be tightened by the vibration of the rotating device or rock drilling machine and cannot be removed by human power.

Japanese Patent Application Laid-Open No. 2002-213174

The problem to be solved by the invention is to use a lightweight, high-strength thin-walled steel pipe with high strength and durability as the outer pipe for drilling, thereby reducing the labor required for attaching and detaching the steel pipe during drilling work. The shortcomings of the protection tube can be easily attached and detached by human power, the protection tube is less likely to come off due to vibration during use, and the thickness of the remaining wall at the end of the protection tube can be prevented from becoming thin. To provide an underground drilling pipe using an excellent high-strength thin-walled steel pipe capable of reducing deformation, displacement and breakage of the end of the protective pipe.

The configuration of the present invention that solves this problem is
1) A plurality of high-strength thin-walled steel pipes with male threads on the outside of the upper ends and female threads on the inside of the lower ends with reversed tapered threads are connected by screwing the male and female tapered threads to each other. to form a long outer tube for drilling, and a long inner rod formed by screwing a plurality of relay rods through a sleeve to the inside of the outer tube for drilling, and
A ring bit is attached to the lower end of the high-strength thin steel pipe that is the lowest stage of the drilling outer tube, an inner bit is attached to the lower end of the inner rod, and the inner bit is the ring bit or the lowest stage to which it is attached. The structure is such that the rotation of the inner bit can be transmitted to the ring bit by engaging with the strong thin steel pipe, and both the ring bit and the inner bit are rotated by the rotation of the inner rod forced to rotate by the rotation device on the ground side. In drilling pipes using high-strength thin-walled steel pipes for drilling underground,
The female tapered threaded part of the hollow cylindrical protection tube is detachably attached to the male tapered threaded part on the outside of the upper end of the high-strength thin steel pipe at the top of the drilled outer tube,
At a position where a clearance δL is generated between the thread start end of the male tapered threaded portion outside the upper end of the uppermost high-strength thin steel pipe and the lower end of the female tapered threaded portion inside the screwed protective tube The screwing can be stopped, the male tapered part of the high-strength thin-walled steel pipe on the uppermost stage can be protected by the protective tube , and the protective tube can be easily removed. Let _L1 be the length of _the male tapered threaded portion of the high-strength thin-walled steel pipe , and _l2 be the length of the female tapered threaded portion of the protection tube _. Thus, even if it is screwed to the end, a gap is reliably generated due to the difference between the lengths l2 _and L1 _. An underground drilled pipe using a high-strength thin-walled steel pipe with a thickness L ₁ in the range of L ₁ /3 to L ₁ /2 2) The pipe thickness d of the high-strength thin-walled steel pipe is 2.0 mm < d < Underground drilled pipe using the high-strength thin-walled steel pipe according to 1) above , which is 5.5 mm 3) The high strength according to any one of 1) or 2) above, wherein the gap distance δL is in the range of 10 to 30 mm Underground drilling pipe using thin steel pipe 4) The material of the high-strength thin steel pipe is high-tensile steel, and the maximum stress T/pa is 400 N to 1000 N/mm ² or more. ) to 3) An underground drilled pipe using the high-strength thin-walled steel pipe according to any one.

In the present invention, by using a high-strength thin-walled steel pipe as an underground drilling pipe, it is possible to make it thin while obtaining high strength and durability. .

In addition, in the present invention, tapered threads are used for the male and female threaded portions at the upper and lower ends of the high-strength thin-walled steel pipe, and the steel pipes are connected manually using tools such as chain tongues, etc., thereby achieving high-strength thin-walled The threaded engagement between the steel pipes by the tapered threads is a strong connection, and even the thin steel pipes have high strength. On the other hand, the inside of the lower part of the hollow cylindrical protective tube, which is screwed into the tapered part of the male screw on the outside of the upper end of the high-strength thin steel pipe at the top, becomes a tapered screw of the female screw. Since there is a gap between the beginning of the tapered thread and the lower end of the tapered thread of the protective tube, it is not tightened to the end, and the screwing stops halfway through the tapered thread of the male thread. The protective tube can be easily screwed on and off by manual operation without being tightened to the maximum. Although the protective tube does not cover the entire length of the tapered thread of the male thread, the protective tube protects the middle and upper end portions of the tapered thread portion where the thickness of the male thread is thin and the strength is reduced. In addition, since the lower end of the tapered thread of the protective tube is shorter than the thread length of the male thread by the clearance interval, the thickness (remaining thickness) of the threaded portion at the lower end of the protective tube is thicker, and this lower end is It is less likely to be deformed, displaced, or damaged by contact with other members or equipment.

Furthermore, since the taper thread portion of the male thread and the tapered thread of the female thread of the protection tube are not tightened to the end, the screwing operation of the protection tube can be easily performed manually, enabling quick attachment and detachment.

If the above clearance δL is the length of the taper threaded portion of the male thread L ₁ and the length of the tapered threaded portion of the protective tube l ₂ , then the clearance spacing δL is the length of (L ₁ - l ₂ ). It can be guaranteed with certainty. Also, the clearance interval δL is practically (L ₁ /3 to L ₁ /2). When the clearance interval δL becomes shorter than L ₁ /3, the tightening state is close to the end, and manual operation takes time. If it is L ₁ /2 or more, the exposed portion of the tapered thread portion of the male thread becomes long, leaving the risk of contact, deformation, displacement, and breakage.

Further, if the pipe thickness d of the high-strength thin-walled steel pipe of the present invention is less than 2.0 mm, the pipe thickness becomes insufficient and the strength of the threaded portion becomes too weak. As a result, the weight of the steel pipe becomes heavy, and the load on moving and screwing the steel pipe increases, and the improvement of workability is weakened. Therefore, it is practical that the pipe thickness d is 2.0 mm<d<5.5 mm.

FIG. 1 is a cross-sectional explanatory view showing the overall structure of the drilled pipe of the embodiment. FIG. 2 is an explanatory diagram of the arrangement of three high-strength thin-walled steel pipes, a ring bit, and a protection pipe forming the drilling outer pipe of the embodiment. FIG. 3 is an explanatory diagram of the configuration of the inner rod of the embodiment. FIG. 4 is an explanatory view showing the screwing state between the taper screw portion Ko of the male screw of the high-strength thin steel pipe _K3 and the taper screw portion Hm of the female screw of the protective tube H of the embodiment. FIG. 5 is an explanatory view showing the screwed state of the uppermost steel pipe of the conventional drilling pipe and the protection pipe.

The high-strength thin-walled steel pipe of the present invention is mainly a long pre-received steel pipe or a high-strength high-tensile steel pipe. The high strength means that the maximum stress T/pa is 400 N/mm2 ^or more, and the thin wall means that the pipe thickness d of the steel pipe is 5.5 mm or less, where 2.0 mm < d < A range of 5.5 mm is a practical range.

The drilling outer pipe of the present invention uses a plurality of high-strength thin-walled steel pipes with a required length of about 3m, and is screwed together at the upper and lower male and female taper threads to achieve a predetermined length (drilling depth). length of the drilled pipe according to One or two intermediate pipes of the same high-strength thin-walled steel pipe are screwed onto one head pipe of a high-strength thin-walled steel pipe for the drilled outer pipe, and a high-strength thin-walled steel pipe (end pipe) is threaded on top of it. are connected with each other. A ring bit is attached to the lower end of the drilled outer tube, and a protective tube is screwed onto the tapered male thread of the uppermost high-strength thin-walled steel tube.
Also, for the inner rod, a plurality of relay rods are connected by a sleeve according to the length of the drilled outer pipe, and an inner bit is attached to the lower end of the inner rod. The inner bit is engaged with the ring bit, and the rotational force of the inner bit is transmitted to the ring bit. A rotating shaft of a rotating device is connected to the upper end of the inner rod via a shank sleeve. If three high-strength thin steel pipes are connected, the length of the drilled pipe will be nearly 10m, and if four high-strength thin steel pipes are connected, the length of the drilled pipe will be nearly 13m. By increasing the number of high-strength thin-walled steel pipes for the intermediate pipes, the length of the drilled pipes can be lengthened. As for the inner rods, the number of relay rods is increased according to the length of the drilled pipe so that the lengths of the inner rods are approximately the same.

Embodiments of the present invention will be described below with reference to the drawings.
_This embodiment, as _shown in FIGS _. The steel pipes K ₁ , K ₂ , and K ₃ have an outer diameter of 114.3 mm, a pipe thickness of 3.5 mm, _and a length of 3.63 m. A high-strength thin-walled steel pipe K 2 (intermediate pipe) made of a material equivalent to or greater than STK-700 with the same diameter and thickness and a length of 3.05 m, and a high-strength steel pipe K ₂ (intermediate pipe) made of STK-400 material with the same outer diameter and the same pipe thickness and a length of 3.10 m Three high-strength thin-walled steel pipes K ₁ , K ₂ , and K ₃ of high-strength thin-walled steel pipe K ₃ (terminal pipe) are used. At the upper and lower ends of the head tube _K1 , the intermediate tube _K2 and the terminal tube (uppermost) _K3 , taper screw portions Ko and Km with a male and female length of 46 mm are provided, and the male and female are screwed together. A long drilling outer tube S of about 8 m is formed.
A ring bit Rb is screwed to the lower end of the drilling outer tube S via a casing shoe Ks. In addition, a hollow cylindrical protection tube H of 73 mm length is provided on the inner circumference of the lower part of the tapered thread Ko of 46 mm length L ₁ of the male screw at the upper end of the uppermost high-strength thin steel tube K ₃ (terminal tube). It is attached by screwing with a tapered threaded portion Hm having a length of 29.2 mm of a female thread. When this protective tube H is screwed to the terminal tube of the high-strength thin steel tube _K3 , the taper thread Ko of the male thread 46 mm length _L1 and the taper thread of the female thread 29.2 mm length _L2 The portion Hm is screwed together, and a clearance interval δL of 46 _mm -29 mm=17 mm is generated between the starting end K31 of the male thread and the lower end _Hm1 of the female thread. In this example, the thickness of the lower end of the tapered threaded portion Hm of the protective tube H is 0.7 mm, which is three times as thick as the thickness of 0.2 mm at the terminal end _K32 of the 46 mm tapered threaded portion Ko. As shown in FIG. 3, an inner rod Ir having a length of about 10 m is formed inside the drilling outer tube S by screwing together three relay rods _Ir1 with two sleeves _Ir2 . there is The upper portion of the inner rod Ir has a structure that interlocks with the rotation output shaft of the rotation device RD via the shank sleeve SS.

Hereinafter, the terms and symbols used in the examples will be explained.
G is a drilled pipe using the three high-strength thin steel pipes K ₁ , K ₂ and K ₃ of high tensile steel of the example, K ₁ is a length of 3.63 m using a material equivalent to STK-700 or more High-strength thin-walled steel pipe (head pipe) with pipe wall thickness d of 3.5mm, _K2 uses material equivalent to STK-700 or higher, length 3.05m, high-strength thin-walled pipe wall thickness d of 3.5mm The steel pipe (intermediate pipe) _K3 is a high-strength thin steel pipe (end pipe) with a length of 3.10 m and a pipe wall thickness d of 3.5 mm using material STK-400. Ko is a male tapered threaded portion with a screw length _L1 of 46 mm at the upper end outer side of the high-strength thin steel pipes _K1 , _K2 , _K3 , and Km is a female at the lower end of the high-strength thin steel pipes _K1 , _K2 , _K3 . _K31 is the beginning of the male tapered thread Ko of the high-strength thin steel pipe _K3 , _K32 is the end of the male tapered thread Ko of the high-strength thin steel pipe _K3 , S is the three high-strength Thin steel pipes K ₁ , K ₂ , K ₃ are screwed together with male and female tapered threads Ko, Km at the upper and lower ends to form a long drilled outer pipe of about 9.8 m. Ks is a high-strength thin steel pipe K _1. 0.14 m casing shoe screwed to the lower end of (head tube), Rb is a drilling ring bit attached to the lower end of the drilling outer tube S through the casing shoe Ks, Ir is the inside of the drilling outer tube S Ir ₁ is a plurality of relay rods with a length of 3.0 to 4.0 m that constitute the inner rod Ir, and Ir ₂ is connected by screwing to the relay rod Ir ₁ . A 19 m long sleeve, Ib is an inner bit attached to the lower end of the inner rod Ir. SS is a shank sleeve that connects the uppermost relay rod _Ir1 and the output shaft of the rotating device RD, and H is a male tapered thread Ko formed on the outside of the upper end of the high-strength thin steel pipe _K3 (terminal pipe). A hollow cylindrical protective tube with a length of 73 mm that is joined and protected, Hh is an insertion hole for a rotating operation rod (not shown) for rotating and screwing the protective tube H, Hm is the lower part of the protective tube H A female tapered threaded portion with a thread length _l2 of 29 mm formed inside, _Hm1 is the lower end of the tapered thread, and δL is the starting end _K31 of the tapered threaded portion Ko of the high-strength thin steel pipe _K3 . A gap distance RD between the lower end _Hm1 of the tapered threaded portion Hm of the protective tube H and RD is a rotating device for rotating the inner rod Ir.

The drilled pipe G using the high-strength thin-walled high-tensile steel pipes _K1 , _K2 , and _K3 of this embodiment has an inner rod Ir shown in FIG. 3 inside the drilled outer pipe S shown in FIGS. A ring bit Rb is attached to the lower end of the drilling outer tube S via a casing shoe Ks. An inner bit Ib is attached to the lower end of the inner rod Ir. A 29 mm long tapered threaded portion Hm of a protective tube H is screwed into the 46 mm long tapered threaded portion Ko of the male thread of the high-strength thin steel pipe _K3 at the top of the drilled outer tube S. A gap δL of about 17 mm is generated between the starting end _K31 of the thread of the threaded portion Ko and the lower end _Hm1 of the tapered threaded portion Hm, so that the tapered threaded portion Hm of the female thread does not engage with the entire length of the tapered threaded portion Ko. The screwing is stopped halfway through. FIG. 4 shows an enlarged view of the screwing with the protective tube H. As shown in FIG.
FIG. 5 shows a state in which tapered threads of the same length are screwed together over the entire thread width in the conventional drilling pipe shown in FIG. Compared to the conventional protective tube H, the protective tube H of the embodiment shown in FIG. 4 of the present invention is not tightened to the full width of the thread, so that the protective tube H can be easily screwed manually.

In addition, since the thread length of the protective tube H is shortened, the tube thickness at the lower end of the tapered thread portion Hm of the female thread is about 0.7 mm, which is 0.2 mm lower than the lower end of the conventional protective tube H shown in FIG. The thickness of the protection tube H is three times or more than the thickness of the tube H, and the strength of the lower end of the protection tube H is high, and deformation, displacement, and breakage due to contact with other equipment can be reduced.

In addition, since most of the thin portions of the middle and upper portions of the tapered screw portion Ko of the male screw of the uppermost high-strength thin-walled steel pipe _K3 are covered with the protective tube H that is screwed together, contact with other equipment is avoided. , the tapered screw portion Ko is rarely deformed, displaced, or damaged.
If it is difficult to screw the protective tube H, it can be securely screwed by inserting a rotating operation rod into the insertion hole Hh of the protective tube H.

Therefore, in this embodiment, since the tapered threaded portion Hm of the female thread of the protective tube H is screwed only halfway through the male tapered threaded portion Ko, it is difficult to remove the protective tube H by tightening the protective tube H. It can be attached and detached easily and quickly by manual work. Furthermore, since the tapered screw portion is used for screwing, there is little loosening of the screw due to vibration.

Moreover, the thickness of the high-strength thin-walled steel pipes _K1 , _K2 , and _K3 can be reduced to about 3.5 mm compared to the conventional steel pipe thickness of 6 mm, and the weight of one steel pipe can be reduced to about 60%, or about 40%. The weight can be reduced, and the labor for moving, attaching, and removing the steel pipe can be greatly reduced.

The present invention can be used not only for borehole pipes in the ground, but also for pipe end protection pipes for aboveground pipes.

G Drilled pipe using high-strength thin-walled steel pipe K ₁ , K ₂ , K ₃ High-strength thin-walled steel pipe Ko Tapered part of male thread at the upper end of high-strength thin-walled steel pipe Km Taper thread of female thread at the lower end of high-strength thin steel pipe Part K ₃₁ Start end of taper thread Ko K ₃₂ End of taper thread Ko S Drilling outer tube Ks Casing shoe Rb Ring bit Ir Inner rod Ir ₁ Relay rod Ir ₂ Sleeve Ib Inner bit SS Shank sleeve H Protective tube Hh Insertion hole Hm Tapered portion of female thread Hm ₁ Lower end L ₁ Length of tapered portion of male thread outside upper end l ₂ Length of tapered portion of female thread of protective tube δL Clearance interval RD Rotating device

Claims (4)

A plurality of high-strength thin-walled steel pipes are connected by screwing the male and female taper threads together. Forming one long outer tube for drilling, disposing a long inner rod formed by screwing a plurality of relay rods through a sleeve inside the outer tube for drilling,
A ring bit is attached to the lower end of the high-strength thin steel pipe that is the lowest stage of the drilling outer tube, an inner bit is attached to the lower end of the inner rod, and the inner bit is the ring bit or the lowest stage to which it is attached. The structure is such that the rotation of the inner bit can be transmitted to the ring bit by engaging with the strong thin steel pipe, and both the ring bit and the inner bit are rotated by the rotation of the inner rod forced to rotate by the rotation device on the ground side. In drilling pipes using high-strength thin-walled steel pipes for drilling underground,
The female tapered threaded part of the hollow cylindrical protection tube is detachably attached to the male tapered threaded part on the outside of the upper end of the high-strength thin steel pipe at the top of the drilled outer tube,
At a position where a clearance δL is generated between the thread start end of the male tapered threaded portion outside the upper end of the uppermost high-strength thin steel pipe and the lower end of the female tapered threaded portion inside the screwed protective tube The screwing can be stopped, the male tapered part of the high-strength thin-walled steel pipe on the uppermost stage can be protected by the protective tube , and the protective tube can be easily removed. Let _L1 be the length of _the male tapered threaded portion of the high-strength thin-walled steel pipe , and _l2 be the length of the female tapered threaded portion of the protection tube _. Thus, even if it is screwed to the end, a gap is reliably generated due to the difference between the lengths l2 _and L1 _. An underground drilling pipe using a high-strength thin-walled steel pipe with a length L ₁ in the range of L ₁ /3 to L ₁ /2. 2. An underground drilling pipe using a high-strength thin-walled steel pipe according to claim 1, wherein the pipe thickness d of said high-strength thin-walled steel pipe is 2.0 mm<d<5.5 mm . An underground drilling pipe using a high-strength thin-walled steel pipe according to claim 1 or 2 , wherein said gap distance δL is in the range of 10 to 30 mm . The high-strength thin-walled steel pipe according to any one of claims 1 to 3 , wherein the high-strength thin-walled steel pipe is made of high-tensile steel and has a maximum stress T/pa of 400 N to 1000 N/mm ² or more. Underground drill pipe used.

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