Drilling tool switching components and jet jet drilling tools
By designing drill tool switching components, switching the three-channel drill rod assembly to dual-channel, the problem of cumbersome and high cost of drill tool replacement in the existing technology is solved, and more efficient construction and resource utilization is achieved.
Patent Information
- Application Number
- CN202110692039.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2021-06-22
- Publication Date
- 2024-12-10
- Estimated Expiration
- 2041-06-22
AI Technical Summary
When switching different construction requirements, existing rotary spray drilling tools need to be disassembled and replaced, resulting in high construction costs, long working hours, large inventory space, and high parts costs.
A drill tool switching assembly was designed, which simplifies drill tool replacement procedures by switching three channels of the drill rod assembly to two channels, reducing disassembly and assembly time and cost, and reducing parts and production costs.
The dual-channel application of three-channel drill rod assembly is realized, which simplifies drill tool replacement procedures, shortens man-time, reduces costs, and reduces inventory space occupation and production resource requirements.
Smart Images
Figure CN113250619B_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of drilling tools of drilling rigs, in particular to a drilling tool switching component and a rotary jet drilling tool. Background Art
[0002] The rotary jet grouting construction method uses a drilling rig to drill a hole, and then uses a high-pressure generating device to spray the slurry out from a high-pressure nozzle at high speed, forming a liquid flow with highly concentrated energy to directly destroy the soil.
[0003] Commonly used high-pressure jet grouting tools include single-, dual-, and triple-drill tools. Single-drill tools have a single channel and can only transport one medium (such as mud) at a time. Dual-drill tools have two channels and can simultaneously transport two media (such as air and mud). For jet grouting applications with large diameters and high pile quality requirements, triple-drill tools are typically used. These tools have three channels and can simultaneously transport three media (such as mud, water, and air). In the existing technology, double drill tools use a drill rod assembly and a joint assembly with two channels, while triple drill tools use a drill rod assembly and a joint assembly with three channels. The drill rod assemblies and the joint assemblies of the double drill tools and the triple drill tools cannot be directly interchanged. When switching drill tools according to different construction requirements, it is necessary to remove the entire set of double drill tools or triple drill tools including the drill rod assembly and the joint assembly, and then replace them with another drill tool. The drill tool replacement procedure is cumbersome and time-consuming, thereby increasing construction costs and extending construction working hours. Moreover, each set of double drill tools and triple drill tools needs to be separately equipped with a matching drill rod assembly and joint assembly, which must be purchased or prepared separately and produced independently. This will take up a large inventory space and production resources, and the cost of parts and production costs are high. Summary of the Invention
[0004] In response to the shortcomings of existing rotary jet drilling tools, the applicant provides a drill tool switching assembly and a rotary jet drilling tool with a reasonable structure. The switching assembly switches the three channels of the drill rod assembly to a dual channel, so that the three-channel drill rod assembly can meet the construction requirements of the dual-channel drilling tool, simplifying the drill tool replacement procedure, reducing the disassembly and assembly time, reducing construction costs, shortening working hours, and reducing the cost of parts and production costs.
[0005] The technical solutions adopted in the present invention are as follows:
[0006] A drilling tool switching assembly, wherein a second inner connecting sleeve is inserted into an outer connecting sleeve, and a nozzle assembly is radially inserted into the outer connecting sleeve and the second inner connecting sleeve; a seventh channel is provided between the second inner connecting sleeve and the outer connecting sleeve, and the bottom of the seventh channel has a blocking structure; an eighth channel with an open top surface and a closed bottom surface is provided in the center of the upper part of the second inner connecting sleeve; a radial through hole is provided on the circumferential wall surface of the second inner connecting sleeve, and the nozzle assembly is inserted into the radial through hole, and the nozzle assembly is respectively connected to the seventh channel and the eighth channel.
[0007] As a further improvement of the above technical solution:
[0008] The second inner connecting sleeve has a first shaft portion, a second shaft portion, and a third shaft portion with outer diameters decreasing successively, and the outer diameter of the third shaft portion is equivalent to the inner diameter of the outer connecting sleeve; the first inner connecting sleeve is mounted on the first shaft portion, and there are several through-flow diversion holes between the first inner connecting sleeve and the outer connecting sleeve, and there is an annular gap between the second shaft portion and the outer connecting sleeve, and the annular gap is connected with the diversion hole to form a seventh channel; the third shaft portion constitutes a blocking structure and is blocked at the bottom of the seventh channel.
[0009] A plurality of sealing rings are provided between the matching surfaces of the third shaft portion and the outer connecting sleeve for sealing; a fourth shaft portion is also provided on the lower side of the third shaft portion, and the outer diameter of the fourth shaft portion is smaller than the outer diameter of the third shaft portion.
[0010] The eighth channel has a countersunk hole at its upper portion.
[0011] A core tube is axially inserted into the bottom of the second inner connecting sleeve.
[0012] A rotary jet drilling tool adopts the above-mentioned drilling tool switching assembly, and the drill rod assembly, the lower joint assembly, and the switching assembly are connected in sequence; the drill rod assembly is a three-layer tube structure, including an outer tube, a middle tube, and an inner tube; there are three channels in the drill rod assembly, the outer channel is between the outer tube and the middle tube, the middle channel is between the middle tube and the inner tube, and the inner channel is in the center of the inner tube; the lower joint assembly includes a lower outer joint, a first lower inner joint, and a second lower inner joint; a fourth channel is connected between the lower outer joint and the first lower inner joint, and the fourth channel is connected to the outer channel; there is a through channel between the first lower inner joint and the second lower inner joint The fifth channel is connected to the middle channel; the center of the second lower inner joint is the sixth channel, which is connected to the inner channel; the upper end of the outer connecting sleeve of the switching assembly is fixedly connected to the lower outer joint, the upper part of the first inner connecting sleeve is sleeved onto the lower part of the first lower inner joint, and the lower part of the second lower inner joint is inserted into the eighth channel of the second inner connecting sleeve, the seventh channel is connected to the fourth channel, and the eighth channel is connected to the sixth channel; the first shaft portion of the second inner connecting sleeve is inserted between the second lower inner joint and the first inner connecting sleeve, and the first shaft portion is blocked at the bottom of the fifth channel.
[0013] As a further improvement of the above technical solution:
[0014] The lower end of the switching assembly is connected with a drill assembly, which includes a drill body and an inner sleeve inserted in the drill body. The drill body is fixedly connected to the outer connecting sleeve, and the core tube is inserted into the inner sleeve.
[0015] The upper end of the drill pipe assembly is connected to an upper joint assembly, which includes an upper external joint, a first upper internal joint, a second upper internal joint and a third upper internal joint; the upper part of the upper external joint is a connecting part, and a first channel is provided between the upper external joint and the first upper internal joint, and the first channel is connected to the external channel; a second channel is provided between the first upper internal joint and the second upper internal joint, and the second channel is connected to the middle channel; a third channel is provided in the center of the third upper internal joint, and the third channel is connected to the internal channel.
[0016] Several sealing rings are respectively provided between the second lower inner joint and the matching surfaces of the first inner connecting sleeve and the second inner connecting sleeve for sealing, and several sealing rings are also provided between the matching surfaces of the first inner connecting sleeve and the first lower inner joint for sealing.
[0017] The lower part of the second lower inner joint is inserted into the countersunk hole of the second inner connecting sleeve.
[0018] The beneficial effects of the present invention are as follows:
[0019] The switching assembly of the present invention connects the outer channel and the inner channel of the drill rod assembly, and at the same time blocks the middle channel of the drill rod assembly, switching the three channels of the drill rod assembly to a dual-channel output, thereby achieving the purpose of using the three-channel drill rod assembly for dual-channel construction, expanding the dual-channel application of the three-channel drill rod assembly, so that the three-channel drill rod assembly can be used for three-channel construction and dual-channel construction at the same time. When switching drilling tools according to different construction requirements, the drill rod assembly does not need to be disassembled, but only the switching assembly and the drill bit assembly need to be disassembled and replaced with corresponding components to carry out the corresponding construction, which simplifies the replacement procedure of the drilling tool, reduces the time for disassembly and assembly of the drilling tool, reduces construction costs, shortens working hours, and improves construction efficiency. Moreover, since the drill rod assembly can be used for both three-channel and dual-channel construction, a set of drill rod assemblies can be used for three-channel drilling tools and dual-channel drilling tools at the same time, reducing the demand for drill rod assemblies, reducing the occupation of inventory space and production resources, and reducing parts costs and production costs. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] Figure 1 It is a front view of the present invention.
[0021] Figure 2 for Figure 1 AA section view of the .
[0022] Figure 3 It is a top view of the present invention.
[0023] Figure 4 for Figure 3 BB cross-sectional view.
[0024] Figure 5 for Figure 4 Enlarged view of part C in the middle.
[0025] Figure 6 for Figure 4 Enlarged view of part D in the middle.
[0026] Figure 7 It is a three-dimensional view of the second inner connecting sleeve.
[0027] In the figure: 100, upper joint assembly; 1, upper outer joint; 2, first upper inner joint; 3, second upper inner joint; 4, third upper inner joint; 18, first channel; 19, second channel; 20, third channel; 30, connecting portion;
[0028] 200, drill pipe assembly; 5, outer tube; 6, middle tube; 7, inner tube; 21, outer channel; 22, middle channel; 23, inner channel;
[0029] 300, lower connector assembly; 8, lower outer connector; 9, first lower inner connector; 10, second lower inner connector; 24, fourth channel; 25, fifth channel; 26, sixth channel;
[0030] 400, switching assembly; 11, outer connecting sleeve; 12, first inner connecting sleeve; 13, second inner connecting sleeve; 14, core tube; 15, nozzle assembly; 27, seventh channel; 28, eighth channel; 281, counterbore; 29, radial through hole; 131, first shaft portion; 132, second shaft portion; 133, third shaft portion; 134, fourth shaft portion;
[0031] 500, drill bit assembly; 16, drill bit body; 17, inner sleeve. DETAILED DESCRIPTION
[0032] The specific embodiments of the present invention will be described below with reference to the accompanying drawings.
[0033] like Figures 1 to 4 As shown, the present invention comprises, from top to bottom, an upper joint assembly 100, a drill rod assembly 200, a lower joint assembly 300, a switching assembly 400, and a drill bit assembly 500; the upper joint assembly 100 and the lower joint assembly 300 are respectively connected to the upper and lower ends of the drill rod assembly 200, the lower joint assembly 300 is connected to the upper end of the switching assembly 400, and the lower end of the switching assembly 400 is connected to the drill bit assembly 500.
[0034] like Figures 2 to 4As shown, the upper joint assembly 100 includes an upper outer joint 1, a first upper inner joint 2, a second upper inner joint 3, and a third upper inner joint 4. The upper portion of the upper outer joint 1 is a connecting portion 30 for connecting to the rotary device; the first upper inner joint 2 is inserted into the upper outer joint 1, and the outer cylindrical surface of the first upper inner joint 2 is provided with a plurality of notches along the axial direction, forming a plurality of through first passages 18 between the outer circumference of the first upper inner joint 2 and the inner circumference of the upper outer joint 1; the second upper inner joint 3 is inserted into the first upper inner joint 2, and the outer cylindrical surface of the second upper inner joint 3 is provided with a plurality of raised key teeth along the circumference, forming a through second passage 19 between adjacent key teeth and the inner circumference of the first upper inner joint 2; the upper portion of the third upper inner joint 4 is inserted into the second upper inner joint 3, and the center of the third upper inner joint 4 has a through third passage 20.
[0035] like Figure 2 、 Figure 4 As shown, the drill pipe assembly 200 is a coaxial three-layer tube structure, which is composed of an outer tube 5, a middle tube 6, and an inner tube 7 from the outside to the inside. The drill pipe assembly 200 has three channels. The annular gap between the inner circumference of the outer tube 5 and the outer circumference of the middle tube 6 constitutes an outer channel 21, the annular gap between the inner circumference of the middle tube 6 and the outer circumference of the inner tube 7 constitutes an intermediate channel 22, and the center of the inner tube 7 is a through inner channel 23. Figure 4 、 Figure 5 As shown, the outer tube 5 is fixed to the upper outer joint 1 by a threaded connection, the middle tube 6 is inserted into the first upper inner joint 2, and the inner tube 7 is sleeved onto the lower outer periphery of the third upper inner joint 4. The first channel 18 is connected to the outer channel 21, the second channel 19 is connected to the middle channel 22, and the third channel 20 is connected to the inner channel 23.
[0036] like Figure 2 、 Figure 4 As shown, the lower joint assembly 300 includes a lower outer joint 8, a first lower inner joint 9, and a second lower inner joint 10. The first lower inner joint 9 is inserted into the lower outer joint 8, and a fourth channel 24 is provided between the first lower inner joint 9 and the lower outer joint 8; the second lower inner joint 10 is inserted into the first lower inner joint 9, and a fifth channel 25 is provided between the second lower inner joint 10 and the first lower inner joint 9; and a sixth channel 26 is provided in the center of the second lower inner joint 10. Figure 4 、 Figure 6 As shown, the lower outer joint 8 is fixedly connected to the lower end of the outer tube 5 by threads, the first lower inner joint 9 is fitted into the lower end of the middle tube 6, the second lower inner joint 10 is inserted into the lower end of the inner tube 7, the fourth channel 24 is connected to the outer channel 21, the fifth channel 25 is connected to the middle channel 22, and the sixth channel 26 is connected to the inner channel 23.
[0037] like Figure 2 、 Figure 4 、 Figure 6As shown, the switching assembly 400 includes an outer connecting sleeve 11, a first inner connecting sleeve 12, a second inner connecting sleeve 13, a core tube 14 and a nozzle assembly 15. Figure 4 、 Figure 6 As shown, the first inner connecting sleeve 12 and the second inner connecting sleeve 13 are inserted into the outer connecting sleeve 11, and the lower part of the first inner connecting sleeve 12 is inserted into the upper part of the second inner connecting sleeve 13; the core tube 14 is inserted into the bottom of the second inner connecting sleeve 13 along the axial direction, and the nozzle assembly 15 is inserted into the outer connecting sleeve 11 and the second inner connecting sleeve 13 along the radial direction. Figure 7 As shown, the second inner connecting sleeve 13 comprises a first shaft portion 131, a second shaft portion 132, a third shaft portion 133 and a fourth shaft portion 134 from top to bottom. The outer diameters of the first shaft portion 131, the second shaft portion 132 and the third shaft portion 133 decrease successively. The outer diameter of the fourth shaft portion 134 is smaller than the outer diameter of the third shaft portion 133. The outer diameter of the third shaft portion 133 is equivalent to the inner diameter of the outer connecting sleeve 11. The lower part of the first inner connecting sleeve 12 is fitted onto the first shaft portion 131. The outer cylindrical surface of the first inner connecting sleeve 12 is provided with a number of notches along the axial direction, and a number of through diversion holes are formed between the outer circumference of the first inner connecting sleeve 12 and the inner circumference of the outer connecting sleeve 11. There is an annular gap between the outer circumference of the second shaft portion 132 and the inner circumference of the outer connecting sleeve 11. The annular gap is connected with the diversion hole of the first inner connecting sleeve 12 to form the seventh channel 27. The third shaft portion 133 constitutes a blocking structure, blocking the bottom of the seventh channel 27. A number of sealing rings are provided between the mating surface of the third shaft portion 133 and the outer connecting sleeve 11 for sealing. Figure 2 、 Figure 4 、 Figure 6 As shown, an eighth channel 28 is provided in the center of the upper portion of the second inner connecting sleeve 13. The eighth channel 28 is a blind hole with an open top and a closed bottom. A countersunk hole 281 is provided on the upper portion of the eighth channel 28. Radial through holes 29 are symmetrically provided on the circumferential wall surfaces on opposite sides of the second shaft portion 132 of the second inner connecting sleeve 13. The radial through holes 29 connect the seventh channel 27 and the eighth channel 28. The nozzle assembly 15 is inserted into the radial through holes 29 and is in conduction with the seventh channel 27 and the eighth channel 28 respectively. Figure 4 、 Figure 6As shown, the upper end of the outer connecting sleeve 11 is threadedly fixed to the lower outer joint 8. The upper portion of the first inner connecting sleeve 12 is inserted into the lower portion of the first lower inner joint 9. The lower portion of the second lower inner joint 10 is inserted into the counterbore 281 of the second inner connecting sleeve 13. The seventh channel 27 connects to the fourth channel 24 and, in turn, to the outer channel 21. The eighth channel 28 connects to the sixth channel 26 and, in turn, to the inner channel 23. The first shaft portion 131 of the second inner connecting sleeve 13 is inserted between the second lower inner joint 10 and the first inner connecting sleeve 12. The first shaft portion 131 forms a blocking structure, blocking the bottom of the fifth channel 25, thereby disconnecting the fifth channel 25 (i.e., the intermediate channel 22). Several sealing rings are provided between the mating surfaces of the second lower inner joint 10, the first inner connecting sleeve 12, and the second inner connecting sleeve 13 for sealing. Several sealing rings are also provided between the mating surfaces of the first inner connecting sleeve 12 and the first lower inner joint 9 for sealing. The switching assembly 400 connects the outer channel 21 and the inner channel 23 of the drill rod assembly 200 through the connecting sleeve, and at the same time blocks the middle channel 22 of the drill rod assembly 200, switching the three channels of the drill rod assembly 200 to a dual-channel output, thereby achieving the purpose of using the three-channel drill rod assembly 200 for dual-channel construction, expanding the dual-channel application of the three-channel drill rod assembly 200, so that the three-channel drill rod assembly 200 can be used for three-channel construction and dual-channel construction at the same time. When switching drilling tools according to different construction requirements, the drill rod assembly 200 does not need to be disassembled, and It is only necessary to remove the switching assembly 400 and the drill bit assembly 500 and replace the corresponding components to carry out the corresponding construction, which simplifies the replacement procedure of the drilling tools, reduces the time for disassembly and assembly of the drilling tools, reduces construction costs, shortens working hours, and improves construction efficiency; and because the drill rod assembly 200 can be used for three-channel and dual-channel construction, a set of drill rod assembly 200 can be used for three-channel drilling tools and dual-channel drilling tools at the same time, reducing the demand for drill rod assemblies 200, reducing the occupation of inventory space and production resources, and reducing parts costs and production costs.
[0038] like Figure 4 As shown, the drill bit assembly 500 includes a drill bit body 16 and an inner sleeve 17 inserted into the drill bit body 16. The drill bit body 16 is fixed to the outer connecting sleeve 11 of the switching assembly 400 through a threaded connection, and the core tube 14 of the switching assembly 400 is inserted into the inner sleeve 17.
[0039] During actual use, the upper joint assembly 100 is connected to the rotary device through the connecting part 30, and the high-pressure slurry is input from the third channel 20, transmitted to the nozzle assembly 15 through the inner channel 23, the sixth channel 26, and the eighth channel 28, and ejected from the nozzle assembly 15; the high-pressure gas is input from the first channel 18, transmitted to the nozzle assembly 15 through the outer channel 21, the fourth channel 24, and the seventh channel 27, and ejected from the nozzle assembly 15; the high-pressure slurry ejected from the nozzle assembly 15 is merged with the high-pressure water to perform double rotary spraying construction.
[0040] The above description is an explanation of the present invention, not a limitation of the present invention. The present invention may be modified in any form without violating the spirit of the present invention.
Claims
1. A drilling tool switching assembly, characterized in that: The second inner connecting sleeve (13) is inserted into the outer connecting sleeve (11), and a nozzle assembly (15) is radially inserted on the outer connecting sleeve (11) and the second inner connecting sleeve (13); a seventh channel (27) is provided between the second inner connecting sleeve (13) and the outer connecting sleeve (11), and the bottom of the seventh channel (27) has a blocking structure; an eighth channel (28) with an open top surface and a closed bottom surface is provided at the center of the upper part of the second inner connecting sleeve (13); a radial through hole (29) is provided on the circumferential wall surface of the second inner connecting sleeve (13), and the nozzle assembly (15) is inserted into the radial through hole (29), and the nozzle assembly (15) is respectively connected to the seventh channel (27) and the eighth channel (28).
2. The drilling tool switching assembly according to claim 1, characterized in that: The second inner connecting sleeve (13) comprises a first shaft portion (131), a second shaft portion (132), and a third shaft portion (133), the outer diameters of which decrease in sequence, and the outer diameter of the third shaft portion (133) is equivalent to the inner diameter of the outer connecting sleeve (11); the first inner connecting sleeve (12) is sleeved on the first shaft portion (131), a plurality of through-flow diversion holes are provided between the first inner connecting sleeve (12) and the outer connecting sleeve (11), and an annular gap is provided between the second shaft portion (132) and the outer connecting sleeve (11), and the annular gap is connected to the diversion holes to form a seventh channel (27); and the third shaft portion (133) constitutes a blocking structure, blocking the bottom of the seventh channel (27).
3. The drilling tool switching assembly according to claim 2, characterized in that: A plurality of sealing rings are arranged between the matching surfaces of the third shaft portion (133) and the outer connecting sleeve (11) for sealing; the third shaft portion (133) also has a fourth shaft portion (134) on the lower side, and the outer diameter of the fourth shaft portion (134) is smaller than the outer diameter of the third shaft portion (133).
4. The drilling tool switching assembly according to claim 1, characterized in that: The eighth channel (28) has a countersunk hole (281) at its upper portion.
5. The drilling tool switching assembly according to claim 1, characterized in that: A core tube (14) is axially inserted into the bottom of the second inner connecting sleeve (13).
6. A rotary jet drilling tool, characterized in that: Using the drilling tool switching assembly as described in any one of claims 1 to 5, the drill rod assembly (200), the lower joint assembly (300), and the switching assembly (400) are connected in sequence; The drill rod assembly (200) is a three-layer tube structure, comprising an outer tube (5), a middle tube (6), and an inner tube (7); the drill rod assembly (200) has three channels, an outer channel (21) is between the outer tube (5) and the middle tube (6), an intermediate channel (22) is between the middle tube (6) and the inner tube (7), and an inner channel (23) is located in the center of the inner tube (7); The lower joint assembly (300) comprises a lower outer joint (8), a first lower inner joint (9) and a second lower inner joint (10); a fourth channel (24) is provided between the lower outer joint (8) and the first lower inner joint (9), and the fourth channel (24) is connected to the outer channel (21); a fifth channel (25) is provided between the first lower inner joint (9) and the second lower inner joint (10), and the fifth channel (25) is connected to the middle channel (22); a sixth channel (26) is provided in the middle of the second lower inner joint (10), and the sixth channel (26) is connected to the inner channel (23); The upper end of the outer connecting sleeve (11) of the switching assembly (400) is fixedly connected to the lower outer joint (8); the upper part of the first inner connecting sleeve (12) is sleeved onto the lower part of the first lower inner joint (9); the lower part of the second lower inner joint (10) is inserted into the eighth channel (28) of the second inner connecting sleeve (13); the seventh channel (27) is connected to the fourth channel (24); and the eighth channel (28) is connected to the sixth channel (26); the first shaft portion (131) of the second inner connecting sleeve (13) is inserted between the second lower inner joint (10) and the first inner connecting sleeve (12); and the first shaft portion (131) is blocked at the bottom of the fifth channel (25).
7. The rotary jet drilling tool according to claim 6, characterized in that: The lower end of the switching assembly (400) is connected to a drill assembly (500), the drill assembly (500) comprising a drill body (16) and an inner sleeve (17) inserted into the drill body (16), the drill body (16) is fixedly connected to the outer connecting sleeve (11), and the core tube (14) is inserted into the inner sleeve (17).
8. The rotary jet drilling tool according to claim 6, characterized in that: The upper end of the drill rod assembly (200) is connected to an upper joint assembly (100), the upper joint assembly (100) comprising an upper outer joint (1), a first upper inner joint (2), a second upper inner joint (3) and a third upper inner joint (4); the upper portion of the upper outer joint (1) is a connecting portion (30); a first channel (18) is provided between the upper outer joint (1) and the first upper inner joint (2), the first channel (18) being connected to an outer channel (21); a second channel (19) is provided between the first upper inner joint (2) and the second upper inner joint (3), the second channel (19) being connected to an intermediate channel (22); and a third channel (20) is provided in the center of the third upper inner joint (4), the third channel (20) being connected to an inner channel (23).
9. The rotary jet drilling tool according to claim 6, characterized in that: A plurality of sealing rings are respectively arranged between the matching surfaces of the second lower inner joint (10), the first inner connecting sleeve (12) and the second inner connecting sleeve (13) for sealing, and a plurality of sealing rings are also arranged between the matching surfaces of the first inner connecting sleeve (12) and the first lower inner joint (9) for sealing.
10. The rotary jet drilling tool according to claim 6, characterized in that: The lower portion of the second lower inner joint (10) is inserted into the countersunk hole (281) of the second inner connecting sleeve (13).