An adaptive screw drill

Abstract

The application provides a self-adaptive screw drill, which comprises a cylindrical shell, a power spindle for connecting a power motor, the power spindle being arranged concentrically in the cylindrical shell and being rotatable relative to the cylindrical shell, the power spindle being provided with a first central flow channel, an output spindle for connecting a drill bit, the output spindle being arranged at a lower end of the power spindle and being provided with a second central flow channel extending in an axial direction, and an elastic member being sleeved on the output spindle, wherein the power spindle is configured to drive the output spindle to rotate so as to transmit power of the power motor to the drill bit, the output spindle is capable of moving upward relative to the power spindle to reduce a soil penetration depth of the drill bit when a torque of the drill bit is too large, the output spindle is capable of generating a pressure pulse when the output spindle moves upward to a highest point, the output spindle compresses the elastic member to store energy during the upward movement of the output spindle, and the output spindle is capable of releasing elastic potential energy after reaching the highest point, so that the output spindle impacts the drill bit under the combined action of the pulse pressure and the elastic member.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of drilling tools, and particularly relates to a self-adaptive screw drill. BACKGROUND

[0002] With the continuous exploitation of oil and gas fields, oil and gas exploration gradually moves to deep layers, the proportion of complex strata and difficult-to-drill strata increases, the rock breaking difficulty increases, and the demand for drilling speed-up technology and tools for oil and gas well engineering is more urgent. In order to meet the construction requirements in difficult-to-drill strata, many speed-up tools based on screw drills have appeared.

[0003] At present, most of the speed-up drilling tools use screw or turbine as the rotating power source, and use the speed difference between the stator and the rotor to drive the hammer to generate impact load. However, the speed-up drilling tools in the prior art still have some problems. For example, most of the speed-up drilling tools have single function, which sacrifices the rotating speed of the screw drill, can only realize axial impact, has low mechanical drilling speed, and has low drilling efficiency. Moreover, when hard strata or deep bit embedment is drilled, the bit torque is too large, which further causes the lag phenomenon of the downhole motor, and even causes the damage of the downhole motor, which seriously affects the efficiency of drilling operation, and the application range of the speed-up drilling tool is small. SUMMARY

[0004] In view of the above technical problems, the present application aims to provide a self-adaptive screw drill, which can make the bit self-adaptively retreat when the bit torque is too large, so as to reduce the bit embedment depth and reduce the bit torque, thereby preventing the lag phenomenon of the downhole motor, and can generate pulse pressure to impact the bit, which is very beneficial to improve the drilling operation efficiency.

[0005] To this end, according to the present application, a self-adaptive screw drill is provided, which comprises: a cylindrical shell; a power main shaft for connecting a power motor, the power main shaft is concentrically arranged in the cylindrical shell and can rotate relative to the cylindrical shell, and the power main shaft is provided with a first central flow channel; an output main shaft for connecting a bit, the output main shaft is arranged at the lower end of the power main shaft and is provided with a second central flow channel extending in the axial direction, and an elastic member is sleeved on the output main shaft; wherein the power main shaft is configured to drive the output main shaft to rotate to transmit the power of the power motor to the bit, the output main shaft can move upward relative to the power main shaft to reduce the bit embedment depth when the bit torque is too large, and can generate a pressure pulse when the output main shaft moves upward to the highest point, at the same time, the output main shaft compresses the elastic member to store energy during the upward movement, and can release the elastic potential energy after reaching the highest point, so that the output main shaft forms an impact on the bit under the joint action of the pulse pressure and the elastic member.

[0006] In one embodiment, a helical spline extending along the axial direction is arranged on the outer wall surface of the output spindle, and a helical spline groove capable of being matched with the helical spline is arranged on the inner wall surface of the power spindle, and the output spindle and the power spindle are connected through the helical spline and the helical spline groove.

[0007] The helical spline can be screwed into the helical spline groove upwardly, so that the output spindle moves upwardly relative to the power spindle.

[0008] In one embodiment, the pitch of the helical spline is arranged in the range of 100-800 mm, and the helix angle of the helix formed by the helical spline extending helically is arranged in the range of 5-85 degrees.

[0009] In one embodiment, the width of the helical spline is arranged in the range of 40-200 mm, and the depth is arranged in the range of 5-20 mm.

[0010] In one embodiment, a first eccentric hole communicating with the first central channel is arranged in the power spindle, the first eccentric hole is at the axial inner end of the helical spline groove, a second eccentric hole communicating with the second central channel is arranged at the upper end of the output spindle, and when the output spindle moves upwardly to the highest point, the first eccentric hole and the second eccentric hole overlap to form a throttle, thereby generating a pressure pulse.

[0011] In one embodiment, an annular limiting groove is arranged on the outer surface of the output spindle, a through hole is arranged on the side wall of the power spindle, and a limiting block is mounted in the through hole, the axial inner end of the limiting block extends into the annular limiting groove,

[0012] The axial width of the annular limiting groove is greater than the width of the limiting block.

[0013] In one embodiment, the cylindrical shell is configured to include an upper shell, a middle joint and a lower shell fixedly connected in sequence from top to bottom.

[0014] In one embodiment, a bearing string is sleeved on the power spindle, the bearing string is arranged between the upper shell and the power spindle, and a first wear-preventing assembly and a second wear-preventing assembly are arranged at both ends of the bearing string.

[0015] In one embodiment, an adjusting check ring and a limiting piece are arranged at both ends of the elastic member respectively, the upper end surface of the adjusting check ring is in contact with the lower end surface of the power spindle, and the limiting piece is fixedly connected with the output spindle,

[0016] The output spindle is compressed by the limiting piece during the upward movement relative to the power spindle.

[0017] In one embodiment, a limiting cylinder is fixed at the lower end of the lower housing, and a centralizing and anti-abrasion assembly is arranged between the limiting cylinder and the output spindle.

[0018] Compared with the prior art, the application has the following advantages:

[0019] The adaptive screw drill according to the application can adapt to downhole working conditions and automatically adjust when the bit torque is too large. Through the cooperation of the helical spline and the helical spline groove of the output spindle, the output spindle can rotate into a certain distance relative to the power spindle and move upward, and the elastic member is compressed to store energy, so as to reduce the bit penetration depth. On the one hand, the bit torque is reduced by reducing the bit penetration depth. On the other hand, the output spindle moves upward relative to the power spindle, and a pressure pulse is generated when the output spindle moves upward to the highest point, so that the generated pressure pulse acts on the output spindle and is then transmitted to the bit, thereby enhancing the bit impact force. At the same time, the elastic member is compressed to store energy during the upward movement of the output spindle, and the elastic potential energy is released after the output spindle reaches the highest point. Thus, the stalling phenomenon of the downhole motor can be effectively prevented. Moreover, the output spindle forms an impact on the bit under the combined action of the pulse pressure and the elastic member, which is very beneficial to improve the downhole working performance of the adaptive screw drill, improve the drilling operation efficiency, and significantly enhance the drilling construction effect. In addition, the adaptive screw drill is easy to operate and can adapt to the actual downhole conditions and automatically adjust during operation, so it has strong adaptability. BRIEF DESCRIPTION OF DRAWINGS

[0020] The application will be described below with reference to the accompanying drawings.

[0021] Figure 1 The structure of the adaptive screw drill according to the application is shown.

[0022] Figure 2 The structure of the helical spline on the output spindle is shown schematically.

[0023] Figure 3 The structure of the helical spline groove on the power spindle is shown schematically.

[0024] Figure 4 The distribution structure of the first eccentric hole on the power spindle and the second eccentric hole on the output spindle is shown schematically.

[0025] In the present application, all the drawings are schematic drawings and are only used to illustrate the principles of the application, and are not drawn to scale. DETAILED DESCRIPTION

[0026] The application will be described below with reference to the accompanying drawings.

[0027] In this application, it should be noted that the end of the adaptive screw drill string according to the present invention that is lowered into the wellbore near the wellhead is defined as the upper end or a similar term, and the end that is far from the wellhead is defined as the lower end or a similar term.

[0028] Figure 1 The structure of the adaptive screw drill 100 according to the present invention is shown. Figure 1 As shown, the adaptive screw drill 100 includes a cylindrical housing 1, a power spindle 2 concentrically arranged within the cylindrical housing 1, and an output spindle 4 for connecting the drill bit. The power spindle 2 is concentrically arranged inside the cylindrical housing 1, and has a first central flow channel 21 extending axially within it for flowing drilling fluid. A bearing string 3 is fitted onto the power spindle 2, forming a rotatable connection between the power spindle 2 and the cylindrical housing 1. The output spindle 4 is concentrically arranged within the cylindrical housing 1 and is located at the lower end of the power spindle 2. The output spindle 4 has a second central flow channel 41 extending axially, and an elastic element 5 is fitted onto the output spindle 4.

[0029] In practical applications, the adaptive screw drill 100 is mounted at the lower end of the downhole power motor (not shown). During operation, the downhole power motor drives the power spindle 2 to rotate. The power spindle 2 is configured to drive the output spindle 4 to rotate, thereby transmitting the power of the downhole power motor to the drill bit. The output spindle 4 can move upward relative to the power spindle 2 when the drill bit torque is too high, thereby reducing the drill bit's soil penetration depth. It can also generate a pressure pulse when the output spindle 4 moves upward to its highest point. Simultaneously, the output spindle 4 compresses the elastic element 5 to store energy during its upward movement and can release the elastic potential energy after reaching the highest point. Thus, the output spindle 4 impacts the drill bit under the combined action of the pulse pressure and the elastic element.

[0030] According to the present invention, such as Figure 1 As shown, the cylindrical housing 1 is constructed comprising an upper outer shell 11, a middle connector 12, and a lower outer shell 13, which are fixedly connected from top to bottom. The power spindle 2 is located within the upper outer shell 11 and the middle connector 12, and the output spindle 4 is located within the lower outer shell 13. The middle connector 12 can be a centralizer (a spiral centralizer or a straight-edged centralizer), enabling the central connector 12 to centralize the adaptive screw drill 100, which greatly enhances the performance of the adaptive screw drill 100.

[0031] In one embodiment, the upper housing 11, the middle connector 12, and the lower housing 13 are all fixedly connected by positive and negative tapered connectors. This connection method is convenient and quick to install, and can effectively ensure the stability of the connection.

[0032] like Figure 1As shown, the bearing string 3 is arranged between the power spindle 2 and the upper housing 11. Preferably, the bearing string 3 is a TC bearing string, which can be a carbide bearing or a tungsten carbide bearing, where TC refers to tungsten carbide, which is a main raw material for producing carbide. The inner ring of the bearing string 3 is fixedly connected to the power spindle 2 in an interference fit, and the outer ring of the bearing string 3 is fixedly connected to the inner wall of the upper housing 11. In this way, the power spindle 2 is rotationally connected to the cylindrical housing 1 through the bearing string 3.

[0033] According to the present application, a first anti-wear assembly 31 and a second anti-wear assembly 32 are arranged at the upper and lower ends of the bearing string 3, respectively. As shown, Figure 1 The first anti-wear assembly 31 is arranged radially between the power spindle 2 and the upper housing 11. The first anti-wear assembly 31 includes a first anti-wear static ring 311 and a first anti-wear dynamic ring 312. The first anti-wear static ring 311 is fixedly connected to the inner wall of the upper housing 11, and the lower end surface of the first anti-wear static ring 311 abuts against the upper end surface of the outer ring of the bearing string 3. In one embodiment, the inner wall of the upper housing 11 is provided with a two-stage step with the end surface facing downward, and the outer wall of the first anti-wear static ring 311 is provided with a two-stage step with the end surface facing upward, and the first anti-wear static ring 311 is axially limited by the two-stage steps when being installed in the upper housing 11. The first anti-wear dynamic ring 312 is fixedly connected to the power spindle 2, and the lower end surface of the first anti-wear dynamic ring 312 abuts against the upper end surface of the inner ring of the bearing string 3. The first anti-wear assembly 31 can effectively prevent wear between the power spindle 2 and the upper housing 11.

[0034] As shown, Figure 1 A jam nut 9 is arranged at the upper end of the first anti-wear assembly 31, and the jam nut 9 is installed on the power spindle 2 in a threaded fastening manner. The jam nut 9 is used to lock the first anti-wear dynamic ring 312 of the first anti-wear assembly 31 on the power spindle 2, so that the first anti-wear dynamic ring 312 is relatively stationary with the power spindle 2, and the first anti-wear dynamic ring 312 is fixedly connected to the power spindle 2, thereby enhancing the stability of the self-adaptive screw drill 100.

[0035] In addition, an adjusting pad can be installed at the upper end of the jam nut 9, which is used as an adjusting member during installation to facilitate installation.

[0036] As shown, Figure 1As shown, the second anti-wear assembly 32 corresponds to the radially inner side of the middle joint 12. The second anti-wear assembly 32 comprises a second anti-wear static ring 321 and a second anti-wear dynamic ring 322. The second anti-wear static ring 321 is fixedly connected with the inner wall of the middle joint 12, and the upper end surface of the second anti-wear static ring 321 abuts against the lower end surface of the outer ring of the compression bearing string 3. In an embodiment, the inner wall of the middle joint 12 is provided with a step with an end surface facing upward, and the lower end surface of the second anti-wear static ring 321 abuts against the step to form axial positioning. The second anti-wear dynamic ring 322 is fixedly connected with the power main shaft 2, and the upper end surface of the second anti-wear dynamic ring 322 abuts against the lower end surface of the inner ring of the compression bearing string 3. The second anti-wear assembly 32 can effectively prevent wear between the power main shaft 2 and the middle joint 12.

[0037] In the working process, the first anti-wear assembly 31 and the second anti-wear assembly 32 can bear the radial force generated by the eccentric motion of the rotor in the downhole motor, the swing of the universal shaft body, and the fixed shaft rotation of the power main shaft 2. Thus, the guiding ability of the self-adapting screw drill 100 and the transmission performance of the power main shaft 2 are improved.

[0038] According to the present application, a clamping assembly can also be arranged between the bearing string 3 and the second anti-wear assembly 32. As shown, Figure 1 The clamping assembly is arranged between the bearing string 3 and the second anti-wear assembly 32 in the axial direction, and the clamping assembly comprises an outer clamping sleeve 33 and an inner clamping sleeve 34. The outer clamping sleeve 33 is used to clamp the lower end surface of the outer ring of the bearing string 3, and the inner clamping sleeve 34 is used to clamp the lower end surface of the inner ring of the bearing string 3. In an embodiment, the inner clamping sleeve 34 is provided with an inner thread, which is fixedly connected with the power main shaft 2 through the inner thread, thereby clamping the inner ring of the bearing string 3 and forming axial positioning of the bearing string 3.

[0039] According to the present application, as shown, Figures 1 to 3 A helical spline 42 extending in the axial direction is arranged on the outer wall surface of the output main shaft 4, and a helical spline groove 22 capable of being matched with the helical spline 42 is arranged on the inner wall surface of the power main shaft 2, and the output main shaft 4 is connected with the power main shaft 2 through the helical spline 42 and the helical spline groove 22. The helical spline 42 can be screwed upward relative to the helical spline groove 22, so that the output main shaft 4 can move upward relative to the power main shaft 2. Thus, on the one hand, the output main shaft 4 can transmit torque through the helical spline 42 and the helical spline groove 22, and on the other hand, the output main shaft 4 can move upward or downward relative to the power main shaft 2 under the action of the helical spline 42 and the helical spline groove 22.

[0040] In one embodiment, taking the 7" drill tool as an example, the pitch of the helical spline 42 is set to be in the range of 100-800 mm, and the helix angle of the helix line formed by the helical extension of the helical spline 42 is set to be in the range of 5-85 degrees. The width of the helical spline 42 is set to be in the range of 40-200 mm, and the depth is set to be in the range of 5-20 mm. Correspondingly, the helical spline groove 22 is adapted to the helical spline 42. In order to facilitate the cooperation of the helical spline 42 and the helical spline groove 22, the width and depth of the helical spline groove 22 are set to be slightly larger than the width and depth of the helical spline 42.

[0041] According to the present application, a first eccentric hole 211 (see Figure 4 ) is arranged in the power spindle 2 and communicates with the first central channel 21. The first eccentric hole 211 is located at the most axially inner end of the helical spline groove 22. At the same time, a second eccentric hole 411 (see Figure 4 ) is arranged at the upper end of the output spindle 4 and communicates with the second central channel 41. Before the output spindle 4 moves upward to the highest point, the first central channel 21 is sequentially communicated with the first eccentric hole 211, the second eccentric hole 411 and the second central channel 41. At this time, there is a certain distance between the axial end surface position provided with the first eccentric hole 211 and the axial end surface position provided with the second eccentric hole 411, and the first eccentric hole 211 is in a fully open state. When the output spindle 4 moves upward to the highest point, the axial end surface position provided with the first eccentric hole 211 coincides with the axial end surface position provided with the second eccentric hole 411, the overlapping area of the first eccentric hole 211 and the second eccentric hole 411 is the smallest, and the first central channel 21 is communicated with the second central channel 41 through the overlapping area of the first eccentric hole 211 and the second eccentric hole 411. Due to the reduction of the overlapping area, throttling is formed, thereby generating a pressure pulse. The generated pulse pressure can act on the upper end surface of the output spindle 4, and then be transmitted to the drill bit, so as to form an axial impact on the drill bit, which is very helpful to enhance the impact force of the drill bit and improve the brick drilling construction.

[0042] As shown in Figures 1 to 3 , an annular limiting groove 43 is arranged on the outer surface of the output spindle 4, a through hole 23 is arranged on the side wall of the power spindle 2, a limiting block 6 is installed in the through hole 23, and the axially inner end of the limiting block 6 extends into the annular limiting groove 43. During the process of the self-adaptive screw drill tool 100 into the well, the limiting block 6 can play a good anti-falling role and effectively prevent the output spindle 4 from falling off.

[0043] During installation, the limiting block 6 passes through the through hole 23 from the outside to the inside and is inserted into the annular limiting groove 43. In order to avoid the limiting block 6 from falling out during work, a sleeve (not shown) is sleeved at the position of the power spindle 2 corresponding to the through hole 23.

[0044] In the embodiment, the axial width of the annular limiting groove 43 is greater than the axial width of the limiting block 6. Moreover, the value of the width of the annular limiting groove 43 minus the axial width of the limiting block 6 is greater than the maximum value of the stroke of the axial movement of the output spindle 4 relative to the power spindle 2, so as to ensure that when the output spindle 4 moves upward to the highest point, the position of the axial end face provided with the first eccentric hole 211 can coincide with the position of the axial end face provided with the second eccentric hole 411.

[0045] According to the present application, the output spindle 4 is concentrically arranged inside the lower housing 13. The elastic member 5 is sleeved on the output spindle 4 and is located between the lower housing 13 and the radial direction of the output spindle 4. As shown in Figure 1 The limiting block 51 and the limiting nut 52 are respectively arranged at the two ends of the elastic member 5. The upper end face of the limiting block 51 is in contact with the lower end face of the power spindle 2, which is used to adjust the pre-tightening force of the elastic member 5. In an embodiment, a gasket can be arranged between the limiting block 51 and the elastic member 5. The limiting member 52 is fixedly connected with the output spindle 4. Preferably, the limiting member 52 is fixedly connected with the output spindle 4 through threads, so as to form axial limiting for the elastic member 5. The elastic member 5 is compressed by the limiting member 52 during the upward movement of the output spindle 4 relative to the power spindle 2, so as to store energy. The elastic member 5 can be a disc spring, for example. In actual construction process, when the drill bit torque is too large, the output spindle 4 can be rotated relative to the power spindle 2 by a certain distance under the cooperation of the helical spline 42 and the helical spline groove 22, so as to move upward and compress the elastic member 5 to store energy, thereby effectively preventing the phenomenon of stalling of the downhole motor.

[0046] As shown in Figure 1 A limiting cylinder 7 is fixedly arranged at the lower end of the lower housing 13. In an embodiment, the limiting cylinder 7 is fixedly connected with the lower housing 13 through threads. A centralizing and anti-wear assembly 8 is arranged between the limiting cylinder 7 and the output spindle 4. The centralizing and anti-wear assembly 8 comprises a centralizing and anti-wear dynamic ring and a centralizing and anti-wear static ring formed on the inner wall of the limiting cylinder 7. The centralizing and anti-wear dynamic ring is fixedly connected with the output spindle 4, for example, through threads. Thus, the wear between the output spindle 4 and the lower housing 13 is effectively prevented by the centralizing and anti-wear assembly 8.

[0047] The working process of the adaptive screw drill 100 according to the present application is briefly described as follows. First, the adaptive screw drill 100 is connected to the lower end of the downhole motor, and after assembly, it is lowered into the wellbore. During the process of being lowered into the wellbore, the output spindle 4 can be effectively prevented from falling under the action of the limiting block 6 and the limiting cylinder 7. When the adaptive screw drill 100 is lowered to a predetermined position in the well, the drill is started. In the normal working state, the downhole power motor drives the power spindle 2 to rotate, and the power spindle 2 drives the output spindle 4 to rotate through the cooperation of the helical spline 42 and the helical spline groove 22, so as to transmit the power of the downhole power motor to the drill bit. When the drill bit torque is too large, the output spindle 4 can automatically adjust to adapt to the downhole working condition. Under the cooperation of the helical spline 42 and the helical spline groove 22, the output spindle 4 can rotate a certain distance relative to the power spindle 2 and move upward, and the elastic member 5 is compressed to store energy, so as to reduce the soil depth of the drill bit. Thus, in the first aspect, the drill bit torque is reduced by reducing the soil depth of the drill bit. In the second aspect, the output spindle 4 moves upward relative to the power spindle 2, and a pressure pulse is generated when the output spindle 4 moves upward to the highest point, so that the generated pressure pulse acts on the output spindle 4 and is then transmitted to the drill bit, thereby enhancing the impact force of the drill bit. At the same time, the elastic member 5 is compressed to store energy during the upward movement of the output spindle 4, and the elastic potential energy is released after the output spindle 4 reaches the highest point. Thus, the output spindle 4 forms an impact on the drill bit under the joint action of the pulse pressure and the elastic member 5. This is very beneficial to improve the downhole working performance of the adaptive screw drill 100, greatly improves the drilling efficiency, and significantly enhances the drilling effect.

[0048] The adaptive screw drill 100 according to the present application can automatically adjust to adapt to the downhole working condition when the drill bit torque is too large. Under the cooperation of the helical spline 42 and the helical spline groove 22, the output spindle 4 can rotate a certain distance relative to the power spindle 2 and move upward, and the elastic member 5 is compressed to store energy, so as to reduce the soil depth of the drill bit. In one aspect, the drill bit torque is reduced by reducing the soil depth of the drill bit. In another aspect, the output spindle 4 moves upward relative to the power spindle 2, and a pressure pulse is generated when the output spindle 4 moves upward to the highest point, so that the generated pressure pulse acts on the output spindle 4 and is then transmitted to the drill bit, thereby enhancing the impact force of the drill bit. At the same time, the elastic member 5 is compressed to store energy during the upward movement of the output spindle 4, and the elastic potential energy is released after the output spindle 4 reaches the highest point. Thus, the downhole motor can be effectively prevented from generating a lag phenomenon. Moreover, the output spindle 4 can form an impact on the drill bit under the joint action of the pulse pressure and the elastic member 5, which is very beneficial to improve the downhole working performance of the adaptive screw drill 100, greatly improves the drilling efficiency, and significantly enhances the drilling effect. In addition, the adaptive screw drill 100 is easy to operate, and can adapt to the actual downhole working condition and automatically adjust during the working process, so it has strong adaptability.

[0049] In the description of the application, the terms "first", "second", "third", etc. are used only to describe purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the application, the meaning of "a plurality of" is two or more, unless otherwise explicitly specified and limited.

[0050] In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting", "fixing" and the like should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium, or it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0051] In the description of the present application, the description of the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present application, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0052] Finally, it should be noted that the above only describes the preferred embodiments of the present application and does not constitute any limitation on the present application. Although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments, or make equivalent replacements to some technical features. Any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. An adaptive screw drill, comprising: a cylindrical shell (1); a power spindle (2) for connecting a power motor, the power spindle being arranged concentrically within the cylindrical shell and being rotatable relative to the cylindrical shell, the power spindle being provided with a first central flow channel (21) extending in an axial direction; an output spindle (4) for connecting a drill bit, the output spindle being arranged at a lower end of the power spindle and being provided with a second central flow channel (41) extending in an axial direction, an elastic member (5) being sleeved on the output spindle; wherein the power spindle is configured to drive the output spindle to rotate to transmit power of the power motor to the drill bit, the output spindle is capable of moving upward relative to the power spindle to reduce the depth of soil resistance of the drill bit when the torque of the drill bit is too large, and is capable of generating a pressure pulse when the output spindle moves upward to a highest point, meanwhile, the output spindle compresses the elastic member to store energy during the upward movement, and is capable of releasing the elastic potential energy after reaching the highest point, so that the output spindle impacts the drill bit under the joint action of the pulse pressure and the elastic member; a helical spline (42) extending in an axial direction is arranged on an outer wall surface of the output spindle, and a helical spline groove (22) capable of adapting to the helical spline is arranged on an inner wall surface of the power spindle, the output spindle and the power spindle are connected through the helical spline and the helical spline groove, and the helical spline is capable of being screwed upward relative to the helical spline groove, so that the output spindle moves upward relative to the power spindle; a first eccentric hole (211) communicating with the first central flow channel is arranged in the power spindle, the first eccentric hole is located at an axial inner end of the helical spline groove, a second eccentric hole (411) communicating with the second central flow channel is arranged at an upper end of the output spindle, and the first eccentric hole and the second eccentric hole overlap to form a throttle when the output spindle moves upward to the highest point, so that a pressure pulse is generated.

2. The adaptive screw-in drill tool of claim 1, wherein, A helical pitch of the helical spline is arranged in a range of 100-800 mm, and a helix angle of a helix line formed by the helical spline extending in a helical shape is arranged in a range of 5-85 degrees.

3. The adaptive screw-in drill tool according to claim 1 or 2, characterized in that A width of the helical spline is arranged in a range of 40-200 mm, and a depth is arranged in a range of 5-20 mm.

4. The adaptive screw-in drill tool of claim 1, wherein, An annular limiting groove (43) is arranged on an outer surface of the output spindle, a through hole (23) is arranged on a side wall of the power spindle, a limiting block (6) is mounted in the through hole, an axial inner end of the limiting block extends into the annular limiting groove, an axial width of the annular limiting groove is greater than a width of the limiting block.

5. The adaptive screw-in drill tool of claim 1, wherein, The cylindrical shell is configured to include an upper shell (11), a middle joint (12) and a lower shell (13) which are fixed and connected in sequence from top to bottom.

6. The adaptive screw-in drill tool of claim 5, wherein, A bearing string (3) is sleeved on the power spindle, the bearing string is arranged between the upper shell and the power spindle, and first and second anti-wear assemblies (31, 32) are arranged at two ends of the bearing string, respectively.

7. The adaptive screw-in drill tool of claim 5, wherein, Adjusting stop ring (51) and limiting member (52) are arranged at both ends of the elastic member respectively, the upper end surface of the adjusting stop ring is in contact with the lower end surface of the power main shaft, the limiting member is fixedly connected with the output main shaft, The output main shaft is moved upward relative to the power main shaft, and the elastic member is compressed by the limiting member.

8. The adaptive screw-in drill tool of claim 7, wherein, The limiting cylinder (7) is fixed at the lower end of the lower shell, and the righting and anti-abrasion assembly (8) is arranged between the limiting cylinder and the output main shaft.

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