Horizontal directional drilling guide butt joint drilling tool

Abstract

The utility model provides a horizontal directional drilling guide butt joint drilling tool which comprises a main drill bit arranged on one side of a main drilling machine and an auxiliary drill bit arranged on one side of an auxiliary drilling machine and in butt joint with the main drill bit, a guide hole for the main drill bit to extend into and guide the main drill bit is formed in the end portion, facing the main drill bit, of the auxiliary drill bit, and a butt joint column is arranged in the guide hole. The butt-joint column is provided with external threads, a butt-joint hole is formed in the end, facing the auxiliary drill bit, of the main drill bit, and the butt-joint hole is provided with internal threads matched with the external threads of the butt-joint column. According to the horizontal directional drilling guide butt joint drilling tool, the main drill bit and the auxiliary drill bit are firmly connected, and accurate butt joint of the main drill bit and the auxiliary drill bit is achieved.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the horizontal directional drilling construction field, concretely relates to a horizontal directional drilling guide butt joint drilling tool. BACKGROUND

[0002] Horizontal directional drilling is a kind of trenchless construction technology for underground pipeline laying, mainly used for laying underground pipelines of petroleum, chemical industry, electric power, communication, gas and water heating, and especially suitable for sensitive areas such as urban roads, rivers and railways, which can avoid the damage to environment and traffic caused by traditional excavation method, has low cost and high safety and efficiency.Horizontal directional drilling machine is composed of drilling machine system, control system, mud system, drilling tool and auxiliary machine tool.Drilling machine system is composed of power control part and hydraulic part, and the drilling machine system is the main body of crossing equipment drilling operation and back dragging operation, equivalent to a person's body.Control system is a directional tool for guiding drilling head to drill correctly by monitoring and controlling the specific position of drilling head underground and other parameters through computer, and the drilling head can drill according to the design curve due to the control of the system, and the control system commands the drilling machine to complete the guide hole operation in directional drilling, equivalent to a person's brain.At present, the control system usually has two forms of hand-held wireless type and wired type, and the wired control mode is usually used in large horizontal directional drilling crossing, that is, the magnetic induction probe receives the earth's magnetic field to generate an electric signal, which is input into the computer after processing, and then the operator controls the direction of the drilling head according to the data reflected in the computer. 1 5 Drilling tool mainly has drilling head suitable for various geologies, mud motor, reamer, cutting knife and drill rod, and the commonly used drill rod specifications are 5

[0003] In the process of directional drilling crossing, with the increase of drilling length, the friction resistance of the drill string to the stratum also increases significantly when the drilling length exceeds 2000 meters, the torsional deformation of the drill string increases, and the relationship between the length of the drill rod and the thrust is shown in Figure 1 and Figure 2 , which leads to the fact that the torque of the drilling machine cannot be transmitted to the drilling head in time, and the drilling head is in discontinuous rotation at the bottom of the well.In this case, it is difficult for the drilling machine to control the orientation of the tool face angle, and there is a certain deviation between the tool face angle displayed on the ground and the actual tool face angle underground, which leads to the loss of control of the drilling direction.Therefore, in order to accurately control the guide direction, ensure the accuracy of the soil point and the completion time of the guide, and reduce the difficulty and risk of single drilling, the guide hole butt joint crossing technology is adopted.

[0004] ​The guiding hole butt joint crossing technology is to set one drilling machine at each end of the out-of-soil point and the into-soil point of the crossing curve, and the two drilling machines are simultaneously guided to the crossing curve in opposite directions according to the design. Usually, the drilling machine at the into-soil side drills for more than half of the crossing length or even longer, which is usually called the main drilling machine. The drilling machine at the out-of-soil side drills for the remaining length, which is usually called the auxiliary drilling machine. When the drill bits of the two drilling machines are within the preset butt joint range, the main drilling machine detects the magnetic signal emitted by the drill bit of the auxiliary drilling machine, determines the relative position of the two drill bits, and then the drill bit of the auxiliary drilling machine is drilled in and the drill bit of the main drilling machine is drilled out, the drill bit of the auxiliary drilling machine is drilled into the hole of the drill bit of the main drilling machine, the drill rod of the main drilling machine is uniformly pulled back, and the auxiliary drilling machine is drilled in the direction of the guiding hole of the main drilling machine at a uniform speed, until the crossing curves of the two drilling machines are completely combined, so that the guiding hole construction is accurately completed and the guiding hole butt joint is completed. In this butt joint mode, the drill bit of the auxiliary drilling machine is not connected with the drill bit of the main drilling machine, but only drilled into the hole of the drill bit of the main drilling machine, which is suitable for crossing in rock stratum with good hole formation. However, in soft stratum and sand layer, the bearing capacity of the hole is low, and the drill bit of the auxiliary drilling machine is easy to run out of the hole after being drilled into the hole of the drill bit of the main drilling machine, resulting in failure of the guiding.

[0005] The Chinese patent CN205277310U discloses a handshake type butt joint drill bit, which comprises a conical surface concave flange locking drill bit and a conical head convex flange locking drill bit, and a scraper blade is connected to each of the conical surface concave flange locking drill bit and the conical head convex flange locking drill bit. The scraper blade of the conical surface concave flange locking drill bit is crossly buckled with the scraper blade of the conical head convex flange locking drill bit, so as to realize the connection of the two drill bits. In the process of moving the drill bit, the connection is not firm, and the two drill bits are easy to separate, resulting in failure of the guiding. Practical new type

[0006] In view of the problems in the prior art, the utility model provides a horizontal directional drilling guiding butt joint drilling tool, which is suitable for butt joint crossing in soft stratum and sand layer, and the main drill bit is connected with the auxiliary drill bit to form an integral whole, so that hole running out is avoided.

[0007] The technical scheme adopted by the utility model is as follows:

[0008] The horizontal directional drilling guiding butt joint drilling tool comprises a main drill bit arranged on one side of a main drilling machine and an auxiliary drill bit arranged on one side of an auxiliary drilling machine and butt jointed with the main drill bit, the end of the auxiliary drill bit facing the main drill bit forms a guiding hole for the main drill bit to extend into and guide the main drill bit, the guiding hole is internally provided with a butt joint column, the butt joint column is provided with external threads, and the end of the main drill bit facing the auxiliary drill bit forms a butt joint hole, the butt joint hole is provided with internal threads matched with the external threads of the butt joint column.

[0009] Further, the auxiliary drill bit is a rod-shaped body, an axial first mud hole is formed in the inside of the auxiliary drill bit and extends to the butt joint column, a first truncated cone body is formed at the end of the auxiliary drill bit opposite to the guiding hole, and the outer wall of the first truncated cone body is provided with first connecting threads connected with a drill rod.

[0010] Further, the butt joint column is a cylindrical body integrated with the auxiliary drill bit, the butt joint column protrudes from the bottom of the pilot hole to the direction of the pilot hole port, the outer diameter of the butt joint column is smaller than the inner diameter of the pilot hole, the annular space is formed between the outer wall of the butt joint column and the inner wall of the pilot hole, and the distance between the outer wall of the butt joint column and the inner wall of the pilot hole is greater than the thickness of the hole wall of the butt joint hole, for example, 1-2 mm, and the length of the butt joint column is preferably smaller than the length of the pilot hole.

[0011] Further, the side wall and the end portion of the butt joint column are distributed with a plurality of first cleaning nozzles for mud spray inside the butt joint column, the first cleaning nozzles are used to communicate the first mud hole and the annular space, the first cleaning nozzles can be circular holes, for example, the first cleaning nozzles arranged on the side wall of the butt joint column are arranged around the butt joint column, the plurality of first cleaning nozzles are distributed in multiple rings at equal intervals, the distance between adjacent rings can be 1 / 5-1 / 4 of the length of the butt joint column, for example, 4-6 first cleaning nozzles are arranged in each ring, the central angles between adjacent first cleaning nozzles in each ring are equal, for example, 60-90 degrees, and the first cleaning nozzles arranged at the end portion of the butt joint column are opposite to the port of the pilot hole. In specific applications, high-pressure mud input from the auxiliary drilling machine enters the inside of the butt joint column from the first mud hole, and is then sprayed out from the first cleaning nozzles. The high-pressure mud entering the first mud hole on the side wall of the butt joint column washes the inner wall of the pilot hole and the outer wall of the butt joint column. The high-pressure mud entering the first mud hole at the end portion of the butt joint column impacts impurities in front of the auxiliary drill bit, and the impurities such as sand and gravel in the annular space are washed out of the pilot hole.

[0012] Further, the end face of the butt joint column forms a first chamfer, the inclination angle of the first chamfer can be 30 degrees, 45 degrees or 60 degrees, for example, the first chamfer is used to avoid hard contact between the butt joint column and the butt joint hole, and to protect the internal thread from damage.

[0013] Further, the outer side of the pilot hole is connected with a trumpet-shaped or truncated cone-shaped introduction cylinder, the small circular port of the introduction cylinder is connected with the pilot hole, the inner diameter of the small circular port of the introduction cylinder is consistent with the inner diameter of the pilot hole, the diameter of the large circular port of the introduction cylinder can be 1.5-2 times the diameter of the small circular port, for example, the height of the introduction cylinder can be 300-400 mm, a plurality of cylindrical first wear-resistant teeth are arranged in a ring shape on the outer surface of the introduction cylinder close to the large circular port, the first wear-resistant teeth are used to protect the outer wall of the introduction cylinder, prevent the cylinder wall from being worn and thinned, and the material of the first wear-resistant teeth can be wear-resistant alloy steel. During the butt joint process of the main drill bit and the auxiliary drill bit, the main drill bit first enters the large circular port of the introduction cylinder, and in the process of advancing, the butt joint hole of the main drill bit is gradually opposite to the butt joint column through the guidance and pilot of the introduction cylinder and the pilot hole, which provides preparation for the rotation of the butt joint column into the butt joint hole, and finally makes the butt joint column rotate into the butt joint hole smoothly, and the main drill bit and the auxiliary drill bit are connected as one.

[0014] Further, the position where the pilot hole is connected with the guide cylinder is chamfered, and the radius of the chamfer can be 4-8 mm, preferably about 6 mm, so as to avoid the main drill entering the pilot hole, to prevent damage to the end of the main drill, and to improve the smoothness of the main drill entering the pilot hole.

[0015] Further, the main drill is a rod-shaped body, and a plurality of cylindrical second wear-resistant teeth extending radially from the main drill are arranged in an annular array on the outer wall of the main drill near the port. The second wear-resistant teeth are used to protect the outer wall of the main drill, prevent the outer wall of the main drill from being worn and thinned, and the material of the second wear-resistant teeth can be wear-resistant alloy steel. The height of the second wear-resistant teeth protruding from the outer wall of the main drill is h, which is less than the difference between the radius of the inner wall of the pilot hole and the radius of the outer wall of the main drill, for example, 1-2 mm, so that the second wear-resistant teeth do not affect the main drill entering the pilot hole. After being guided and aligned by the guide cylinder and the pilot hole, the main drill accurately captures the butt joint column. The rod body of the main drill is provided with an axial second mud hole, and a spacing is formed between the second mud hole and the butt joint hole. A second truncated cone is formed at the end of the main drill opposite to the second wear-resistant teeth. The outer wall of the second truncated cone is provided with a second connecting thread for connecting with the drill pipe.

[0016] Further, the spacing is provided with a plurality of second cleaning nozzles distributed in a diverging manner. The second cleaning nozzles spray high-pressure mud in the second mud hole into the butt joint hole for cleaning impurities such as mud and sand in the butt joint hole. The plurality of second cleaning nozzles form inner, middle and outer rings around the central axis of the butt joint hole. Each ring is provided with at least three second cleaning nozzles. The central angles between adjacent second cleaning nozzles in each ring are equal. The second cleaning nozzles in the inner ring are inclined towards the port of the butt joint hole. The second cleaning nozzles in the middle ring are inclined towards the middle of the butt joint hole. The second cleaning nozzles in the outer ring are inclined towards the bottom of the butt joint hole. In specific applications, high-pressure mud input from the main drilling machine enters the second mud hole, and then enters the butt joint hole through the second cleaning nozzles in the inner, middle and outer rings. The high-pressure mud entering from the second cleaning nozzles in the inner ring flushes the impurities near the port of the butt joint hole. The high-pressure mud entering from the second cleaning nozzles in the middle ring flushes the impurities in the middle of the butt joint hole. The high-pressure mud entering from the second cleaning nozzles in the outer ring flushes the impurities at the bottom of the butt joint hole. The butt joint hole is cleaned in all directions to remove impurities in the butt joint hole, so as to avoid the impurities interfering with the threaded connection between the butt joint column and the butt joint hole.

[0017] Further, the length direction of the butt joint hole is consistent with the central axis direction of the main drill, the inner diameter of the butt joint hole matches the outer diameter of the butt joint column, the hole port end face of the butt joint hole forms an inner chamfer inside the hole port and an outer chamfer outside the hole port, the inclination angle of the inner chamfer is the same as that of the first chamfer, and the inclination angle of the outer chamfer can be 30 degrees, 45 degrees or 60 degrees. In specific applications, the inner chamfer is arranged to allow the butt joint column to smoothly slide into the butt joint hole, so as to realize the threaded connection between the butt joint column and the butt joint hole.

[0018] The docking process of a horizontal directional drilling guide docking tool of this utility model is as follows:

[0019] Before entering the docking area, the main drilling rig and auxiliary drilling rig are each connected to conventional drill bits. Their respective directional control systems manipulate their conventional drill bits to reach the docking area. Then, the conventional drill bits are pulled out along the guide holes, disassembled, and replaced with the main drill bit and auxiliary drill bit of this invention, which are then advanced to the original docking area. During the docking process, the auxiliary drill bit does not rotate or advance, while the main drill bit rotates and advances. During advancement, the main drill bit first enters the inlet tube. Guided by the inlet tube, the main drill bit smoothly enters the guide hole, which limits the main drill bit. The main drill bit pauses for a period of time after advancing a short distance to allow the main and auxiliary drill bits to clean away mud and other impurities. When the directional control system indicates that the main drill bit has advanced to the docking post of the auxiliary drill bit, the pause time needs to be extended to allow the main and auxiliary drill bits to thoroughly clean away mud and impurities. Then, the main drill bit is screwed into the auxiliary drill bit, and the main and auxiliary drill bits are connected by threads to form a single unit. The main drilling rig then drags the integrated main and auxiliary drill bits out of the soil, completing the guiding operation.

[0020] The beneficial effects of this utility model are:

[0021] This utility model provides a horizontal directional drilling guide and docking tool. By setting a guide hole, the main drill bit is limited, ensuring that the central axes of the main drill bit and auxiliary drill bit coincide, allowing for precise positioning of the main drill bit. A docking post set within the guide hole and a docking hole set within the main drill bit are used. The docking post has external threads, and the docking hole has internal threads matching the external threads of the docking post. The docking post is threadedly connected to the main drill bit, enhancing the stability of the connection between the main and auxiliary drill bits and preventing them from disengaging during movement. An inlet sleeve guides the main drill bit to the guide hole, allowing the docking hole to smoothly align with the docking post. First and second cleaning nozzles are used to flush the auxiliary and main drill bits, removing impurities that have entered the drill bits. This utility model provides a horizontal directional drilling guide and docking tool where the main and auxiliary drill bits are threadedly connected as one unit, suitable for directional hole construction in soft formations. Attached Figure Description

[0022] Figure 1 This is a graph showing the relationship between drill pipe advance length and drilling rig thrust.

[0023] Figure 2 This is a graph showing the relationship between drill pipe drilling length and torque.

[0024] Figure 3 This is an overall schematic diagram of a horizontal directional drilling guide docking tool according to the present invention.

[0025] Figure 4 for Figure 3 The main view.

[0026] Figure 5 is Figure 4 a sectional view along the A-A direction in

[0027] Figure 6 is a sectional view of the main drill bit.

[0028] Figure 7 is a schematic view of the main drill bit and the auxiliary drill bit during the docking process.

[0029] Figure 8 is a schematic view of the main drill bit guiding.

[0030] BRIEF DESCRIPTION OF DRAWINGS

[0031] 1-auxiliary drill bit, 2-introduction cylinder, 3-main drill bit, 4-docking column, 5-guiding hole, 6-first mud hole, 7-first cleaning nozzle, 8-inner thread, 9-second cleaning nozzle, 10-second mud hole, 11-outer thread, 12-second wear-resistant tooth, 13-first chamfer, 14-docking hole, 15-interval, 16-inner chamfer, 17-outer chamfer, 18-first wear-resistant tooth, 19-first connecting thread, 20-second connecting thread. DETAILED DESCRIPTION

[0032] The utility model will be explained in detail below with reference to the drawings.

[0033] As Figures 3-8 shown, the utility model provides a kind of horizontal directional drilling guiding docking drilling rig, it includes the main drill bit 3 of being set to the one side of main drill machine, the auxiliary drill bit 1 of being set to the one side of auxiliary drilling machine and with the main drill bit 3 docking, the end of auxiliary drill bit 1 towards main drill bit 3 forms the guiding hole 5 for main drill bit 3 to extend and guide main drill bit 3, guiding hole 5 inside is equipped with docking column 4, docking column 4 is equipped with outer thread 11, the end of main drill bit 3 towards auxiliary drill bit 1 forms docking hole 14, docking hole 14 is equipped with the inner thread 8 matching with the outer thread 11 of docking column 4.

[0034] Auxiliary drill bit 1 is pole-like body, the first mud hole 6 of axial is opened in the inside of auxiliary drill bit 1, first mud hole 6 extends to docking column 4, first truncated cone body is formed on the end of auxiliary drill bit opposite guiding hole, and the outer wall of first truncated cone body is equipped with the first connecting thread 19 connected with drill rod.

[0035] Docking column 4 is the cylindrical body integrally formed with auxiliary drill bit 1, docking column 4 protrudes from the bottom of guiding hole 5 to the direction of guiding hole 5 port, the outer diameter of docking column 4 is less than the inner diameter of guiding hole 5, annular space is formed between the outer wall of docking column 4 and the inner wall of guiding hole 5, and the distance between the outer wall of docking column 4 and the inner wall of guiding hole 5 is greater than the hole wall thickness of docking hole 14, for example, 1-2mm, the length of docking column 4 is preferably less than the length of guiding hole 5, and the length of guiding hole 5 is generally 400-500mm.

[0036] The side wall and end portion of the docking column 4 are provided with a plurality of first cleaning nozzles 7 for spraying the mud inside the docking column 4, the first cleaning nozzles 7 can be circular holes for example, the inner diameter of the first cleaning nozzles 7 can be 3-4 mm for example, the first cleaning nozzles 7 arranged on the side wall of the docking column 4 are arranged around the docking column 4, the plurality of first cleaning nozzles 7 are arranged in multiple rings at equal intervals, the distance between adjacent rings can be 1 / 5-1 / 4 of the length of the docking column 4 for example, 4-6 first cleaning nozzles 7 are arranged in each ring, the central angles between adjacent first cleaning nozzles 7 in each ring are equal, which can be 60-90 degrees for example, the first cleaning nozzles 7 arranged at the end of the docking column 4 are opposite the port of the pilot hole. In specific applications, high-pressure mud input from the auxiliary drilling machine enters the inside of the docking column 4 from the first mud hole 6, and is then sprayed out by the first cleaning nozzles 7. The high-pressure mud entering the first mud hole on the side wall of the docking column 4 washes the inner wall of the pilot hole 5 and the outer wall of the docking column 4, and the high-pressure mud entering the first mud hole at the end of the docking column 4 impacts impurities in front of the auxiliary drill bit, and the impurities such as sand and gravel in the annular space are washed out of the pilot hole 5.

[0037] A first chamfer 13 is formed on the end face of the docking column 4, the inclination angle of the first chamfer 13 can be 30 degrees, 45 degrees or 60 degrees for example, and the first chamfer 13 is used to avoid hard contact between the docking column 4 and the docking hole 14, and to protect the internal thread 8 from damage.

[0038] The outer side of the pilot hole 5 is connected with a trumpet-shaped or truncated cone-shaped introduction cylinder 2, the small circular port of the introduction cylinder 2 is connected with the pilot hole 5, the inner diameter of the small circular port of the introduction cylinder 2 is consistent with the inner diameter of the pilot hole 5, the diameter of the large circular port of the introduction cylinder 2 can be 1.5-2 times the diameter of the small circular port for example, and the height of the introduction cylinder 2 can be 300-400 mm for example. A plurality of cylindrical first wear-resistant teeth 18 are arranged in a circular array on the outer surface of the introduction cylinder 2 close to the large circular port, the first wear-resistant teeth 18 are used to protect the outer wall of the introduction cylinder 2, prevent the cylinder wall from being worn and thinned, and the material of the first wear-resistant teeth 18 can be wear-resistant alloy steel for example. During the docking process of the main drill bit 3 and the auxiliary drill bit 1, the main drill bit 3 first enters the large circular port of the introduction cylinder 2, and in the process of advancing, the docking hole 14 of the main drill bit 3 is gradually aligned with the docking column 4 through the guidance and alignment of the introduction cylinder 2 and the pilot hole 5, which provides preliminary preparation for the rotation of the docking column 4 into the docking hole 14, and finally makes the docking column 4 smoothly rotate into the docking hole 14, and the main drill bit 3 and the auxiliary drill bit 1 are connected into one body.

[0039] The position where the pilot hole 5 is connected with the introduction cylinder 2 is rounded, the radius of the round corner can be 4-8 mm for example, preferably 6 mm, which avoids damage to the end portion of the main drill bit 3 when the main drill bit 3 enters the pilot hole 5, and improves the smoothness of the main drill bit 3 entering the pilot hole 5.

[0040] The main drill bit 3 is a rod-shaped body, and a plurality of cylindrical second wear-resistant teeth 12 are arranged in an annular array on the outer wall of the main drill bit 3 close to the port, and the second wear-resistant teeth 12 are used to protect the outer wall of the main drill bit 3 to prevent the outer wall of the main drill bit 3 from being worn and thinned, and the material of the second wear-resistant teeth 12 can be, for example, wear-resistant alloy steel, and the height h of the second wear-resistant teeth 12 protruding from the outer wall of the main drill bit 3 is set to be smaller than the difference between the inner wall radius of the pilot hole and the outer wall radius of the main drill bit, for example, 1-2 mm, so that the second wear-resistant teeth 12 do not affect the entry of the main drill bit 3 into the pilot hole 5, and h can be, for example, 2-3 mm. After being guided and aligned by the guide sleeve 2 and the pilot hole 5, the main drill bit 3 accurately captures the butt joint column 4, the rod body of the main drill bit 3 is provided with an axial second mud hole 10, and a spacing part 15 is formed between the second mud hole 10 and the butt joint hole 14. A second truncated cone body is formed at the end of the main drill bit opposite to the second wear-resistant teeth, and the outer wall of the second truncated cone body is provided with a second connecting thread 20 connected with the drill rod.

[0041] The spacing part 15 is provided with a plurality of second cleaning nozzles 9 distributed in a diverging manner, the second cleaning nozzles 9 spray high-pressure mud in the second mud hole 10 into the butt joint hole 14 for cleaning impurities such as mud and sand in the butt joint hole 14, and the inner diameter of the second cleaning nozzle 9 can be, for example, 3-4 mm. The plurality of second cleaning nozzles 9 are distributed in an inner ring, a middle ring and an outer ring around the central axis of the butt joint hole 14, at least three second cleaning nozzles 9 are arranged in each ring, the central angles between adjacent second cleaning nozzles 9 in each ring are equal, the second cleaning nozzles in the inner ring are inclined toward the port of the butt joint hole 14, the second cleaning nozzles in the middle ring are inclined toward the middle part of the butt joint hole 14, and the second cleaning nozzles in the outer ring are inclined toward the bottom of the butt joint hole 14. In specific applications, high-pressure mud input from the main drilling machine enters the second mud hole 10 and then enters the butt joint hole 14 through the second cleaning nozzles 9 in the inner ring, the middle ring and the outer ring, respectively. Among them, the high-pressure mud entering from the second cleaning nozzles 9 in the inner ring flushes the impurities near the port of the butt joint hole 14, the high-pressure mud entering from the second cleaning nozzles 9 in the middle ring flushes the impurities in the middle part of the butt joint hole 14, and the high-pressure mud entering from the second cleaning nozzles 9 in the outer ring flushes the impurities at the bottom of the butt joint hole 14. The butt joint hole 14 is cleaned in all directions to remove impurities in the butt joint hole 14, so as to avoid the interference of impurities with the threaded connection between the butt joint column 4 and the butt joint hole 14. The diameters of the first mud hole and the second mud hole are generally 40-60 mm.

[0042] The length direction of the butt joint hole 14 is consistent with the central axis direction of the main drill bit 3, the inner diameter of the butt joint hole 14 matches the outer diameter of the butt joint column 4, the hole opening end face of the butt joint hole 14 forms an inner chamfer 16 located inside the hole opening and an outer chamfer 17 located outside the hole opening, the inclination angle of the inner chamfer 16 is the same as the inclination angle of the first chamfer 13, and the inclination angle of the outer chamfer 17 can be, for example, 30 degrees, 45 degrees or 60 degrees, and in specific applications, the inner chamfer 16 is arranged to allow the butt joint column 4 to smoothly slide into the butt joint hole 14, thereby achieving the threaded connection of the butt joint column 4 and the butt joint hole 14.

[0043] The butt joint process of the horizontal directional drilling guide butt joint drilling tool of the utility model is as follows:

[0044] Before entering the butt joint area, the main drilling machine and the auxiliary drilling machine are respectively connected with conventional drill bits (the hole forming diameter of the conventional drill bit is greater than the large circular port diameter of the lead-in cylinder 2), the steering systems of the main drilling machine and the auxiliary drilling machine respectively control the conventional drill bits to reach the butt joint area, and then the conventional drill bits are pulled out along the guide holes and disassembled to be replaced by the main drill bit 3 and the auxiliary drill bit 1 of the utility model and pushed into the original butt joint area. During the butt joint process, the auxiliary drill bit 1 does not rotate and advance, and the main drill bit 3 rotates and advances. During the advancing process, the main drill bit 3 first enters the lead-in cylinder 2, is guided by the lead-in cylinder 2, and then smoothly enters the pilot hole 5, the pilot hole 5 limits the main drill bit 3, and the main drill bit 3 stops for a period of time for cleaning the silt impurities of the main drill bit 3 and the auxiliary drill bit 1 every time it advances a small distance. When the steering system displays that the main drill bit 3 advances to the butt joint column of the auxiliary drill bit 1, the stopping time needs to be lengthened, the main drill bit 3 and the auxiliary drill bit 1 are completely cleaned of silt impurities, the main drill bit 3 is screwed into the auxiliary drill bit 1, the main drill bit 3 and the auxiliary drill bit 1 are integrated through threaded connection, and then the main drilling machine pulls out the integrated main drill bit 3 and auxiliary drill bit 1 to realize the guiding work.

[0045] The preferred embodiments of the utility model are described above, however, the above description is not used for the purpose of limitation. Those skilled in the art can make many changes or modifications to the utility model without deviating from the main idea and range of the utility model. The changes or modifications should be included in the range of the appended claims.

Claims

1. A horizontal directional drilling pilot butt drill, characterized by, It includes the main drill bit (3) arranged on one side of the main drilling machine, the auxiliary drill bit (1) arranged on one side of the auxiliary drilling machine and butted with the main drill bit (3), the end of the auxiliary drill bit (1) facing the main drill bit (3) forms a pilot hole (5) for the main drill bit (3) to extend into and correct the main drill bit (3), the pilot hole (5) is provided with a butt joint column (4), the butt joint column (4) is provided with an external thread (11), the end of the main drill bit (3) facing the auxiliary drill bit (1) forms a butt joint hole (14), the butt joint hole (14) is provided with an internal thread (8) matched with the external thread (11) of the butt joint column (4).

2. The horizontal directional drill pilot bit drill tool of claim 1, wherein, The auxiliary drill bit (1) is a rod-shaped body, and the inside of the auxiliary drill bit (1) is provided with an axial first mud hole (6) extending to the butt joint column (4).

3. The horizontal directional drill pilot bit drill tool of claim 2, wherein, The butt joint column (4) is a cylindrical body integrally formed with the auxiliary drill bit (1), the butt joint column (4) protrudes from the bottom of the pilot hole to the direction of the pilot hole port, the outer diameter of the butt joint column (4) is smaller than the inner diameter of the pilot hole (5), and the annular space is formed between the outer wall of the butt joint column (4) and the inner wall of the pilot hole (5), and the distance between the outer wall of the butt joint column (4) and the inner wall of the pilot hole (5) is greater than the hole wall thickness of the butt joint hole (14).

4. The horizontal directional drill pilot bit as defined in claim 3, wherein, The side wall and end of the butt joint column (4) are provided with a plurality of first cleaning nozzles (7) for mud spraying in the butt joint column (4), the first cleaning nozzles (7) arranged on the side wall of the butt joint column (4) are arranged around the butt joint column (4), the plurality of first cleaning nozzles (7) are distributed in multiple rings at equal intervals, and the first cleaning nozzles (7) arranged on the end of the butt joint column (4) are opposite to the port of the pilot hole.

5. A horizontal directional drilling pilot bit as claimed in claim 3 or 4, characterised in that, The end face of the butt joint column (4) forms a first chamfer (13).

6. The horizontal directional drill pilot bit of claim 1, wherein, The outer side of the pilot hole (5) is connected with a trumpet-shaped or truncated cone-shaped introduction cylinder (2), the small circular port of the introduction cylinder (2) is connected with the pilot hole (5), the large circular port of the introduction cylinder (2) has a diameter of 1.5-2 times of the small circular port, and the outer surface of the introduction cylinder (2) near the large circular port is arranged with annular array of cylindrical first wear-resistant teeth (18).

7. The horizontal directional drill pilot bit drill tool of claim 6, wherein, The position where the pilot hole (5) is connected with the introduction cylinder (2) is treated with round corner.

8. The horizontal directional drill pilot bit of claim 1, wherein, The main drill bit (3) is a rod-shaped body, and the outer wall of the main drill bit (3) near the port is arranged with annular array of cylindrical second wear-resistant teeth (12) extending in the radial direction of the main drill bit (3), the rod body of the main drill bit (3) is provided with an axial second mud hole (10), and the second mud hole (10) and the butt joint hole (14) form a spacing part (15).

9. The horizontal directional drill pilot bit drill tool of claim 8, wherein, The spacing part (15) is provided with a plurality of second cleaning nozzles (9) for mud spraying and distributed in a diverging manner, the plurality of second cleaning nozzles (9) form inner, middle and outer rings around the central axis of the butt joint hole (14), at least three second cleaning nozzles (9) are arranged in each ring, the central angles between adjacent second cleaning nozzles (9) in each ring are equal, the second cleaning nozzles (9) in the inner ring are inclined towards the port of the butt joint hole (14), the second cleaning nozzles (9) in the middle ring are inclined towards the middle part of the butt joint hole (14), and the second cleaning nozzles (9) in the outer ring are inclined towards the bottom of the butt joint hole (14).

10. The horizontal directional drill pilot bit of claim 1, wherein, The length direction of the butt joint hole (14) is consistent with the central axis direction of the main drill bit (3), the inner diameter of the butt joint hole (14) matches the outer diameter of the butt joint column (4), the hole opening end face of the butt joint hole (14) forms an inner chamfer (16) located inside the hole opening and an outer chamfer (17) located outside the hole opening, and the inclination angle of the inner chamfer (16) is the same as the inclination angle of the first chamfer (13).

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