Jet drill bit for directional hydraulic fracturing in coal mine underground

Abstract

The present application provides a kind of jet drill bit for coal mine underground directional fracturing, it is related to the technical field of auxiliary equipment for coal mine exploitation, including drill bit main body, shaft cylinder and linkage mechanism, drill bit main body and shaft cylinder are arranged along the first direction interval;On the projection plane orthogonal to the first direction, the projection outer contour of drill bit main body is located in the projection outer contour outside each of shaft cylinder and linkage mechanism;Linkage mechanism includes push-pull rod, first swing bar, second swing bar and locking assembly, push-pull rod is pivotally connected with the inner cavity of shaft cylinder;The first end of each of first swing bar and second swing bar is slidably connected with push-pull rod along the radial direction of drill bit main body, the second end of each of first swing bar and second swing bar is pivotally connected with drill bit main body, and four-sided unit is formed between first swing bar, drill bit main body, second swing bar and push-pull rod.The present application adjusts drill bit angle by using linkage mechanism, the overall size of linkage mechanism is small, and it can enter the drilled hole with drill bit simultaneously, which significantly expands the drilling range.

Description

Technical Field

[0001] This invention relates to the field of auxiliary equipment technology for coal mine drilling, and in particular to a jet drill bit for directional fracturing in coal mines. Background Technology

[0002] In coal mine operations, jet drill bits are typically used for directional fracturing of coal seams to improve coal seam permeability and gas extraction efficiency. Jet drill bits mainly utilize the impact force of high-pressure water jets to break rocks and fracture coal seams. First, a high-pressure water pump pressurizes water and delivers it to the jet drill bit through the drill rod. Then, the water is ejected at high speed from the jet nozzle of the jet drill bit, forming a water jet with a strong impact force that impacts the coal seam rock, causing the rock to break and form cracks. At the same time, by controlling the direction and angle of the jet, directional fracturing can be achieved, allowing the cracks to expand in a predetermined direction.

[0003] However, the components used to adjust the angle of the jet drill bit in related technologies are often large in size. During coal mine drilling, only the drill bit head extends into the borehole, while the components cannot enter the drilled hole simultaneously with the drill bit. Therefore, the effective drilling depth of the jet drill bit as a whole is limited, which greatly restricts its drilling range. Summary of the Invention

[0004] The present invention aims to at least partially solve one of the technical problems in the related art.

[0005] Therefore, embodiments of the present invention propose a jet drill bit for directional fracturing in coal mines. This jet drill bit for directional fracturing in coal mines uses a linkage mechanism to adjust the drill bit angle. The linkage mechanism has a small overall size and can enter the drilled hole synchronously with the drill bit, significantly expanding the drilling range.

[0006] According to an embodiment of the present invention, a jet drill bit for directional fracturing in coal mines includes a drill bit body, a shaft, and a linkage mechanism. The drill bit body and the shaft are arranged at intervals along a first direction, and the first direction forms an angle with the radial direction of the drill bit body. On a projection plane orthogonal to the first direction, the projected outer contour of the drill bit body is located outside the projected outer contour of each of the shaft and the linkage mechanism. The linkage mechanism includes a push-pull rod, a first swing rod, a second swing rod, and a locking assembly. The push-pull rod is pivotally connected to the inner cavity of the shaft cylinder. The first swing rod and the second swing rod are arranged radially spaced along the drill bit body. The first end of each of the first swing rod and the second swing rod is slidably connected to the push-pull rod radially along the drill bit body. The second end of each of the first swing rod and the second swing rod is pivotally connected to the drill bit body. The first swing rod, the drill bit body, the second swing rod, and the push-pull rod form a quadrilateral unit. The locking assembly can lock the push-pull rod and the inner cavity of the shaft cylinder when the push-pull rod is pivoted to any position relative to the inner cavity of the shaft cylinder.

[0007] According to an embodiment of the present invention, a jet drill bit for directional fracturing in coal mines comprises a drill bit body, a shaft, and a linkage mechanism to construct a jet drill bit structure with angle adjustment function, so as to control the direction and angle of the jet and achieve directional fracturing. The first and second swing arms are slidably connected to a push-pull rod along the radial direction of the drill bit body. Both the first and second swing arms are pivotally connected to the drill bit body, and a quadrilateral unit is formed between the first swing arm, the drill bit body, the second swing arm, and the push-pull rod. Therefore, by rotating the push-pull rod, the first and second swing arms can be pushed and pulled to swing relative to the push-pull rod, thereby causing the drill bit body to deflect relative to the shaft, that is, changing the angle between the drill bit body and the shaft. The locking assembly can lock the push-pull rod after adjustment, thus... The jet drill bit's jet direction and angle are adjusted. Simultaneously, on a projection plane orthogonal to the first direction, the outer contour of the drill bit's main body is located outside the outer contour of the projection of each of the shaft and the linkage mechanism. That is, the overall radial dimension of the angle adjustment device formed by the shaft and the linkage mechanism is smaller than the radial dimension of the drill bit's main body. This allows the jet drill bit to enter the drilled hole synchronously with the drill bit's main body, completely solving the problem of limited drilling depth caused by the excessively large size of the angle adjustment device (i.e., the supporting component used to adjust the angle of the jet drill bit) in traditional equipment. Therefore, compared with related technologies, this invention uses a linkage mechanism to adjust the drill bit's angle. The linkage mechanism has a small overall size and can enter the drilled hole synchronously with the drill bit, significantly expanding the drilling range.

[0008] In some embodiments, both the first rocker arm and the second rocker arm include a support portion and a pressing portion pivotally connected to each other. One end of the support portion opposite to the pressing portion is pivotally connected to the drill bit body. One end of the pressing portion opposite to the support portion is slidably connected to the push-pull rod along the radial direction of the drill bit body. The pressing portion is slidably connected to the shaft cylinder along the first direction.

[0009] In some embodiments, the linkage mechanism further includes a drive assembly disposed in the inner cavity of the shaft cylinder, and the drive assembly is throttle-connected to the push-pull rod so that the push-pull rod can rotate relative to the shaft cylinder.

[0010] In some embodiments, the drive assembly includes a telescopic cylinder and a push box, the cylinder body of the telescopic cylinder being connected to the inner cavity of the shaft cylinder; the telescopic rod of the telescopic cylinder being connected to the push box to push and pull the push box relative to the shaft cylinder to move in the first direction, and the side of the push box opposite to the telescopic cylinder being connected to the push-pull rod so that the push-pull rod can rotate relative to the shaft cylinder.

[0011] In some embodiments, the inner wall surface of the shaft cylinder is provided with a positioning groove, the locking assembly includes a positioning block, the positioning block is slidably connected to the push box along the radial direction of the drill bit body, and the positioning block has a locking position that cooperates with the positioning groove and an unlocking position that is spaced apart from the positioning groove; The positioning slots are at least one and are arranged at intervals along the first direction.

[0012] In some embodiments, the positioning block has a guide surface facing the positioning groove, and when the positioning block switches between the locked position and the unlocked position, the guide surface is movably connected to the positioning groove along a second direction, the second direction forming an angle with both the first direction and the radial direction of the drill bit body.

[0013] In some embodiments, the push box has a receiving cavity, and the positioning block is slidably connected to the receiving cavity along the radial direction of the drill bit body. When the positioning block is switched from the locked position to the unlocked position, the positioning block is completely located in the receiving cavity.

[0014] In some embodiments, the locking assembly further includes a movable plate, a connecting rod, and an elastic element. The movable plate is disposed in the receiving cavity. A first end of the connecting rod is pivotally connected to the movable plate, and a second end of the connecting rod is pivotally connected to the positioning block. The movable plate has a first position and a second position. When the positioning block switches from the locking position to the unlocking position, the movable plate can slide relative to the receiving cavity from the first position to the second position along the first direction. The elastic element is clamped between the movable plate and the inner wall surface of the receiving cavity and can press the movable plate towards the second position.

[0015] In some embodiments, the drive assembly further includes a pressing plate disposed in the receiving cavity and arranged with the movable plate along the first direction, the pressing plate being closer to the push-pull rod than the movable plate; At least a portion of the telescopic rod of the telescopic cylinder is located in the receiving cavity and is slidably connected to the receiving cavity along the first direction. The extrusion plate is connected to the telescopic rod of the telescopic cylinder and is capable of sliding relative to the receiving cavity along the first direction to drive the push box or the moving plate.

[0016] In some embodiments, the drill bit body is provided with a jet nozzle, and the jet drill bit further includes a delivery pipe, a collection box, and a connecting pipe. The delivery pipe is disposed in the inner cavity of the shaft cylinder and located on the outer periphery of the linkage mechanism. The inlet of the delivery pipe is adapted to communicate with the external high-pressure water source. The collection box is located between the drill bit body and the shaft cylinder. The outlet of the delivery pipe, the collection box, the connecting pipe, and the jet nozzle are connected in sequence. The connecting pipe is a flexible pipe. The conveying pipes are at least one and are arranged at circumferential intervals along the shaft.

[0017] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of a jet drill bit for directional fracturing in coal mines according to an embodiment of the present invention.

[0019] Figure 2 This is a schematic diagram of the middle position of a jet drill bit for directional fracturing in coal mines according to an embodiment of the present invention.

[0020] Figure 3 This is a schematic diagram of the connection structure of the drill bit body, shaft, and linkage mechanism in a jet drill bit for directional fracturing in coal mines according to an embodiment of the present invention (the shaft is cut in the figure).

[0021] Figure 4 yes Figure 3 A magnified schematic diagram of the structure at point A in the middle.

[0022] Figure 5 This is a schematic diagram of the connection structure between the drill bit body and the linkage mechanism in a jet drill bit for directional fracturing in coal mines according to an embodiment of the present invention.

[0023] Figure 6 This is an exploded structural diagram of the push-pull rod, locking assembly, and drive assembly in a jet drill bit for directional fracturing in coal mines according to an embodiment of the present invention.

[0024] Figure label: 1. Drill bit body; 11. Notch; 12. Jet nozzle; 2. Shaft sleeve; 21. Positioning groove; 3. Linkage mechanism; 31. Push-pull rod; 311. Extrusion groove; 32. First swing rod; 321. Support part; 322. Extrusion part; 323. First pressure shaft; 324. Second pressure shaft; 325. Third pressure shaft; 326. Guide block; 327. Guide groove; 33. Second swing rod; 34. Locking assembly; 341. Positioning block; 3411. Guide surface; 342. Moving plate; 343. Linkage rod; 344. Elastic element; 35. Drive assembly; 351. Telescopic cylinder; 352. Push box; 3521. Receiving cavity; 353. Push seat; 354. Push shaft; 355. Extrusion plate; 4. Conveying pipe; 5. Collector box; 6. Connecting pipe. Detailed Implementation

[0025] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0026] like Figures 1 to 6 As shown in the figure, an embodiment of the present invention provides a jet drill bit for directional fracturing in coal mines, comprising a drill bit body 1, a shaft 2, and a linkage mechanism 3. The drill bit body 1 and the shaft 2 are arranged at intervals along a first direction, which forms an angle with the radial direction of the drill bit body 1. On a projection plane orthogonal to the first direction, the projected outer contour of the drill bit body 1 is located outside the projected outer contour of each of the shaft 2 and the linkage mechanism 3.

[0027] The linkage mechanism 3 includes a push-pull rod 31, a first swing rod 32, a second swing rod 33, and a locking assembly 34. The push-pull rod 31 is pivotally connected to the inner cavity of the shaft cylinder 2. The first swing rod 32 and the second swing rod 33 are arranged radially at intervals along the drill bit body 1. The first end of each of the first swing rod 32 and the second swing rod 33 is slidably connected to the push-pull rod 31 radially along the drill bit body 1. The second end of each of the first swing rod 32 and the second swing rod 33 is pivotally connected to the drill bit body 1. The first swing rod 32, the drill bit body 1, the second swing rod 33, and the push-pull rod 31 form a quadrilateral unit. The locking assembly 34 can lock the push-pull rod 31 and the inner cavity of the shaft cylinder 2 when the push-pull rod 31 is pivoted to any position relative to the inner cavity of the shaft cylinder 2.

[0028] According to an embodiment of the present invention, a jet drill bit for directional fracturing in coal mines is constructed by the cooperation of a drill bit body 1, a shaft cylinder 2, and a linkage mechanism 3 to form a jet drill bit structure with angle adjustment function, so as to control the direction and angle of the jet and realize directional fracturing. The first swing rod 32 and the second swing rod 33 are both slidably connected to the push-pull rod 31 along the radial direction of the drill bit body 1. The first swing rod 32 and the second swing rod 33 are both pivotally connected to the drill bit body 1, and a quadrilateral unit is formed between the first swing rod 32, the drill bit body 1, the second swing rod 33, and the push-pull rod 31. Therefore, by rotating the push-pull rod 31, the first swing rod 32 and the second swing rod 33 can be pushed and pulled to swing relative to the push-pull rod 31, thereby pulling the drill bit body 1 to deflect relative to the shaft cylinder 2, that is, changing the angle between the drill bit body 1 and the shaft cylinder 2. The locking assembly 34 can... After adjustment, the push-pull rod 31 is locked, thereby completing the adjustment of the jet direction and angle of the jet drill bit. At the same time, on the projection plane orthogonal to the first direction, the projected outer contour of the drill bit body 1 is located outside the projected outer contour of each of the shaft cylinder 2 and the linkage mechanism 3. That is, the overall radial dimension of the angle adjustment device formed by the shaft cylinder 2 and the linkage mechanism 3 is smaller than the radial dimension of the drill bit body 1, so that the jet drill bit can enter the drilled hole synchronously with the drill bit body 1. This completely solves the problem that the drilling depth is limited by the excessive size of the angle adjustment device (i.e., the matching component used to adjust the angle of the jet drill bit) in traditional equipment. Therefore, compared with related technologies, the present invention uses the linkage mechanism 3 to adjust the drill bit angle. The linkage mechanism 3 has a small overall size and can enter the drilled hole synchronously with the drill bit, which significantly expands the drilling range.

[0029] Specifically, when the drill bit body 1 does not deflect relative to the shaft 2, that is, when both the drill bit body 1 and the shaft 2 are parallel to the drilled hole, the drill bit body 1 can be arranged coaxially with the shaft 2. In this case, the axial direction of the drill bit body 1 is the same as the axial direction of the shaft 2 and both are consistent with the first direction. The specific structure of the drill bit body 1 can adopt the existing technology in this field, and will not be elaborated here.

[0030] The direction of the pivot axis of the push-pull rod 31 at the shaft cylinder 2, and the direction of the pivot axis of each of the first rocker arm 32 and the second rocker arm 33 at the drill body 1, can be orthogonal to the first direction and also orthogonal to the arrangement direction of the first rocker arm 32 and the second rocker arm 33. For example, as shown in the figure, the direction of the pivot axis of the aforementioned components can be the up-down direction in the figure, the first direction can be the left-right direction in the figure, and the arrangement direction of the first rocker arm 32 and the second rocker arm 33 can be the front-back direction in the figure. The drill body 1 can be located on the left side of the shaft cylinder 2. The push-pull rod 31 can extend along the front-back direction in the figure, and the first end of each of the first rocker arm 32 and the second rocker arm 33 is slidably connected to the push-pull rod 31 along the front-back direction in the figure. The middle position of the push-pull rod 31 can be pivotally connected to the inner cavity of the shaft cylinder 2. The first rocker arm 32 and the second rocker arm 33 can be mirror-symmetrical with respect to a reference plane, which is orthogonal to the first direction and coplanar with the center of the push-pull rod 31.

[0031] like Figures 1 to 5 As shown, in some embodiments, the first rocker arm 32 and the second rocker arm 33 both include a support portion 321 and a pressing portion 322 that are pivotally connected to each other. The end of the support portion 321 away from the pressing portion 322 is pivotally connected to the drill body 1. The end of the pressing portion 322 away from the support portion 321 is slidably connected to the push-pull rod 31 along the radial direction of the drill body 1. The pressing portion 322 is slidably connected to the shaft cylinder 2 along the first direction.

[0032] It is understandable that designing the first swing arm 32 and the second swing arm 33 to include a support part 321 and a pressing part 322 can effectively reduce the extent to which the first swing arm 32 and the second swing arm 33 extend beyond the outside of the drill bit body 1 in the front-back direction. This allows for the adjustment of the set deflection angle of the drill bit body 1 relative to the shaft cylinder 2, while reducing the space occupied by the linkage mechanism 3 in the drilled hole, which is beneficial to further improve the drilling application range of the jet drill bit.

[0033] Specifically, a notch 11 can be formed on the side wall of the drill bit body 1. The support part 321 can be pivotally connected to the drill bit body 1 via a first pressure shaft 323 so that the support part 321 can rotate relative to the notch 11. The support part 321 can be pivotally connected to the extrusion part 322 via a second pressure shaft 324. An extrusion groove 311 extending in the front-back direction can be formed on the push-pull rod 31. There are two extrusion grooves 311, which are mirror-symmetrical with respect to the aforementioned reference plane. The extrusion part 322 can be slidably connected to the extrusion groove 311 in the front-back direction via a third pressure shaft 325.

[0034] Furthermore, a guide structure may be provided between the extrusion part 322 and the shaft cylinder 2 so that the extrusion part 322 can reliably slide relative to the shaft cylinder 2 in the left-right direction. For example, the guide structure may include a guide block 326 and a guide groove 327. One of the inner wall surfaces of the extrusion part 322 and the shaft cylinder 2 is provided with a guide block 326, and the other is provided with a guide groove 327. At least a portion of the guide block 326 is slidably fitted in the guide groove 327 in the first direction.

[0035] like Figure 3 As shown, in some embodiments, the linkage mechanism 3 further includes a drive component 35, which is disposed in the inner cavity of the shaft cylinder 2. The drive component 35 is connected to the push-pull rod 31 so that the push-pull rod 31 can rotate relative to the shaft cylinder 2, thereby driving the push-pull rod 31 to move by the drive component 35, thereby improving the automation level of the jet drill bit. At the same time, placing the drive component 35 in the inner cavity of the shaft cylinder 2 can reduce the corrosive damage of the external environment to the drive component 35 and ensure the service life of the drive component 35.

[0036] like Figure 3 As shown, in some embodiments, the drive assembly 35 includes a telescopic cylinder 351 and a push box 352. The cylinder body of the telescopic cylinder 351 is connected to the inner cavity of the shaft cylinder 2. The telescopic rod of the telescopic cylinder 351 is connected to the push box 352 to push and pull the push box 352 to move relative to the shaft cylinder 2 in a first direction. The side of the push box 352 away from the telescopic cylinder 351 is connected to the push-pull rod 31 so that the push-pull rod 31 can rotate relative to the shaft cylinder 2.

[0037] Understandably, using the telescopic cylinder 351 can simplify the driving method of the linkage mechanism 3, which is conducive to simplifying the overall structure of the jet drill bit and reducing the later maintenance cost.

[0038] Specifically, the telescopic cylinder 351 is not limited to one of the following: hydraulic cylinder, electric cylinder, oil cylinder, and pneumatic cylinder. The central axis of the telescopic cylinder 351 can be coplanar with the aforementioned reference plane. The telescopic rod of the telescopic cylinder 351 can be connected to the middle position of the push box 352. A push seat 353 can be provided on the side of the push box 352 away from the telescopic cylinder 351, and the push seat 353 is arranged near the front end of the push box 352. A push shaft 354 can be provided on the side of the push seat 353 away from the push box 352, and the push shaft 354 can slide in cooperation with the aforementioned extrusion groove 311.

[0039] like Figure 3 and Figure 4As shown, in some embodiments, the inner wall of the shaft cylinder 2 is provided with a positioning groove 21, and the locking assembly 34 includes a positioning block 341. The positioning block 341 is slidably connected to the push box 352 along the radial direction of the drill bit body 1. The positioning block 341 has a locking position that cooperates with the positioning groove 21 and an unlocking position that is spaced apart from the positioning groove 21. In other words, the positioning block 341 is inserted into the positioning groove 21 in the locking position, and the positioning block 341 is dislodged from the positioning groove 21 in the unlocking position.

[0040] The positioning groove 21 is at least one and is arranged at intervals along the first direction.

[0041] It is understandable that, since the positioning block 341 is connected to the push box 352, and the telescopic cylinder 351 pushes and pulls the push box 352 to achieve the push-pull operation of the push rod 31, when the positioning block 341 is engaged in the positioning groove 21, the push box 352 can be limited along the first direction to lock the position of the push rod 31 on the shaft cylinder 2, thereby realizing the linkage of angle adjustment and position locking of the drill bit body 1 relative to the shaft cylinder 2.

[0042] By using multiple positioning slots 21, multi-level adjustment of the angle between the drill bit body 1 and the shaft 2 can be further realized, enabling the jet drill bit to adapt to more downhole directional fracturing scenarios.

[0043] like Figures 4 to 6 As shown, in some embodiments, the positioning block 341 has a guide surface 3411 facing the positioning groove 21. When the positioning block 341 switches between the locked position and the unlocked position, the guide surface 3411 is movably connected to the positioning groove 21 along a second direction. The second direction forms an angle with the first direction and the radial direction of the drill body 1. That is, the guide surface 3411 is inclined to facilitate the removal action of the positioning block 341 from the positioning groove 21 or the insertion action of the positioning block 341 into the positioning groove 21.

[0044] like Figure 6 As shown, in some embodiments, the push box 352 has a receiving cavity 3521, and the positioning block 341 is slidably connected to the receiving cavity 3521 along the radial direction of the drill bit body 1. When the positioning block 341 is switched from the locked position to the unlocked position, the positioning block 341 is completely located in the receiving cavity 3521, so that the positioning block 341 can retract into the receiving cavity 3521 in the unlocked position, reducing the erosion damage of the positioning block 341 by external environmental factors, and at the same time further improving the integration of the jet drill bit and reducing the space occupation.

[0045] Specifically, the positioning block 341 can be slidably connected to the receiving cavity 3521 in the vertical direction shown in the figure. At least a portion of the positioning block 341 extends out of the receiving cavity 3521 in the locked position.

[0046] like Figure 6As shown, in some embodiments, the locking assembly 34 further includes a movable plate 342, a connecting rod 343, and an elastic element 344. The movable plate 342 is disposed in the receiving cavity 3521. The first end of the connecting rod 343 is pivotally connected to the movable plate 342, and the second end of the connecting rod 343 is pivotally connected to the positioning block 341. The movable plate 342 has a first position and a second position. When the positioning block 341 switches from the locked position to the unlocked position, the movable plate 342 can slide relative to the receiving cavity 3521 from the first position to the second position along a first direction. The elastic element 344 is sandwiched between the movable plate 342 and the inner wall surface of the receiving cavity 3521 and can press the movable plate 342 towards the second position.

[0047] It is understandable that the linkage structure is formed by the sequential pivoting connection of the moving plate 342, the connecting rod 343 and the positioning block 341. When the moving plate 342 slides along the first direction, the positioning block 341 can be pulled out or retracted relative to the receiving cavity 3521 by the connecting rod 343, so as to realize the switching of the positioning block 341 between the locked position and the unlocked position.

[0048] The elastic element 344 can not only provide a restoring force for the moving plate 342 to return to the second position, but also exert a pressing force on the moving plate 342 toward the second position when external factors act on the positioning block 341 and cause the moving plate 342 to move toward the first position, so as to prevent the influence of external forces on the moving plate 342, limit the moving plate 342, and further ensure the position reliability of the positioning block 341.

[0049] Specifically, the movable plate 342 is slidably connected to the receiving cavity 3521 in the left-right direction. The movable plate 342 may be provided with a first hinge seat, and the first end of the connecting rod 343 is hinged to the first hinge seat. The positioning block 341 may be provided with a second hinge seat, and the second end of the connecting rod 343 is hinged to the second hinge seat. The elastic element 344 can be a spring, which can extend in the left-right direction. One end of the spring can be connected to the inner wall of the receiving cavity 3521, and the other end of the spring can be connected to the movable plate 342. In the first position, the elastic element is in a stretched state, and the elastic restoring force of the spring will pull the movable plate 342 back to its original position. In the second position, the spring is at its free length.

[0050] like Figure 6 As shown, in some embodiments, the drive assembly 35 further includes a pressing plate 355, which is disposed in the receiving cavity 3521 and arranged with the moving plate 342 along a first direction, and the pressing plate 355 is closer to the push-pull rod 31 than the moving plate 342.

[0051] At least a portion of the telescopic rod of the telescopic cylinder 351 is located in the receiving cavity 3521 and is slidably connected to the receiving cavity 3521 in a first direction. The extrusion plate 355 is connected to the telescopic rod of the telescopic cylinder 351 and can slide relative to the receiving cavity 3521 in a first direction to drive the push box 352 or the moving plate 342.

[0052] It is understandable that the telescopic rod of the telescopic cylinder 351 extends so that the extrusion plate 355 abuts against the inner wall of the receiving cavity 3521, thereby driving the push box 352 to rotate. When the telescopic rod of the telescopic cylinder 351 retracts, the extrusion plate 355 presses against the moving plate 342 to drive the moving plate 342, causing the moving plate 342 to move in the left and right directions. The moving plate 342 drives the positioning block 341 to retract into the receiving cavity 3521 through the linkage rod 343. The positioning block 341 disengages from the positioning groove 21. Thus, the telescopic cylinder 351 is used to realize the linkage control of the angle adjustment, position locking and position reset of the drill bit body 1 relative to the shaft cylinder 2, further optimizing the overall structure of the jet drill bit.

[0053] Specifically, the extrusion plate 355 and the telescopic rod of the telescopic cylinder 351 are fixedly connected to the portion of the receiving cavity 3521. For example, as shown in the figure, the push-pull rod 31 is located on the left side of the push box 352, and the extrusion plate 355 is located on the left side of the moving plate 342.

[0054] like Figures 1 to 3 As shown, in some embodiments, the drill bit body 1 is provided with a jet nozzle 12. The jet drill bit also includes a delivery pipe 4, a collector box 5, and a connecting pipe 6. The delivery pipe 4 is located in the inner cavity of the shaft cylinder 2 and on the outer periphery of the linkage mechanism 3 so as not to affect the normal operation of the linkage mechanism 3. The inlet of the delivery pipe 4 is suitable for communication with an external high-pressure water source. The collector box 5 is located between the drill bit body 1 and the shaft cylinder 2. The outlet of the delivery pipe 4, the collector box 5, the connecting pipe 6, and the jet nozzle 12 are connected in sequence. The connecting pipe 6 is a flexible pipe and can be located in the drill bit body 1 and on the left side of the collector box 5.

[0055] The delivery pipe 4 is at least one and is arranged at intervals along the circumference of the shaft cylinder 2 to ensure the supply of high-pressure water to the jet drill bit.

[0056] Understandably, the collector box 5 can collect the high-pressure water transported by the temporary conveying pipe 4, so that the collector box 5 can supply the high-pressure water to the nozzle 12 through the connecting pipe 6 and spray it out at high speed, forming a water jet with strong impact force, impacting the coal seam rock, causing the rock to break and form cracks, thus achieving directional fracturing.

[0057] Therefore, compared with related technologies, the present invention has the following advantages: 1) The overall size of the linkage mechanism of the present invention is smaller than that of the drill bit body. It has a compact structure and is integrated inside the shaft. It can enter the drilled hole synchronously with the drill bit body, which completely solves the problem that the drilling depth is limited due to the inability of the angle adjustment device to keep up with the traditional equipment, and significantly expands the drilling range. 2) This invention can achieve multi-level angle adjustment. The telescopic cylinder drives the box to move, and the positioning block is connected to multiple positioning slots for positioning. The linkage transmission of the push rod, the extrusion part and the support part enables the multi-level angle adjustment of the jet drill bit. Compared with the traditional single angle adjustment method, it can adapt to more downhole directional fracturing scenarios. 3) The present invention has a simplified structure and stable operation. It abandons the traditional complex multi-group adjustment mechanism and achieves angle adjustment and positioning lock simultaneously through integrated linkage design with telescopic cylinder as the power core. This reduces component redundancy, reduces the risk of blockage and damage under highly corrosive and highly viscous working conditions, and extends the service life of the equipment.

[0058] The working process of this jet drill bit for directional fracturing in underground coal mines will now be explained in detail, based on its specific structure: 1) Connect the shaft cylinder to the external power machinery and connect the delivery pipe to the high-pressure water source fittings. Control the operation of the telescopic cylinder through an external controller. 2) Activate the telescopic cylinder, causing its telescopic rod to move towards the push box. This push rod then presses against the inner wall of the push box, causing it to move towards the drill bit body within the shaft cylinder. The movement of the push box drives the positioning block to move. During this movement, the guide surface of the positioning block presses against the side wall of the positioning groove. Since the side wall of the positioning groove is fixed, the positioning block retracts into the push box during this process. This retraction of the positioning block acts on the connecting rod, causing the other end of the connecting rod to push the moving plate. The movement of the moving plate stretches the spring, thus supporting the retraction of the positioning block. Simultaneously, the movement of the push box also drives the push seat and push shaft to move. The movement of the push shaft presses against the inner wall of the extrusion groove. The force on the inner wall of the extrusion groove acts on the push-pull rod, causing it to rotate in the direction of the push shaft's movement. When the pull rod rotates, the extrusion groove will extrude the third pressure shaft at the corresponding position. One of the third pressure shafts will move towards the drill body under pressure, while the other third pressure shaft will move away from the drill body. The movement of the third pressure shaft will drive the extrusion part to move. The movement of the extrusion part will drive the guide block to move inside the guide groove. The movement of the extrusion part will act on the corresponding support part through the second pressure shaft. The second pressure shaft moving towards the drill body will apply a thrust to the corresponding support part, and the second pressure shaft moving towards the shaft cylinder will apply a tension to the corresponding support part. At this time, the two support parts will drive the drill body to rotate through the support of the first pressure shaft. The drill body will rotate towards the first pressure shaft under tension, and the flexible connecting pipe on one side of the drill body will also deform adaptively. 3) After the drill bit body has finished rotating, the push box also moves the positioning block to the positioning slot adjacent to the initial positioning slot. At this time, the spring will drive the moving plate to reset. The moving plate drives the positioning block to reset through the linkage rod. The positioning block resets upward and is inserted into the corresponding positioning slot, thus completing the second-level angle adjustment. The remaining two unconnected positioning slots represent the third and fourth levels of drill bit body angle adjustment. 4) When the drill bit body needs to be reset, only the telescopic rod of the telescopic cylinder needs to retract. The retracted output end will drive the extrusion plate to move towards the moving plate. When the extrusion plate moves to a position adjacent to the moving plate, it will extrude pressure on the moving plate. The moving plate, under pressure, will move towards the telescopic cylinder. The movement of the moving plate will cause the positioning block to move downward actively with the linkage rod and separate from the connected positioning groove. The positioning block is no longer connected to the positioning groove, thus releasing the positioning of the push box moving towards the telescopic cylinder. When the moving plate moves to its maximum extent inside the push box, the moving plate will transmit the thrust to the push box, causing the push box to drive the various components to reset, thereby resetting the drill bit body to its original position. The entire linkage mechanism will not affect the drilling depth of the drill bit body, thus freeing the drill bit body from its usage limitations.

[0059] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0060] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0061] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0062] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0063] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0064] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A jet drill bit for directional fracturing in coal mines, characterized in that, include: The drill bit body and the shaft are arranged at intervals along a first direction, and the first direction forms an angle with the radial direction of the drill bit body. In the linkage mechanism, on a projection plane orthogonal to the first direction, the projected outer contour of the drill bit body is located outside the projected outer contour of each of the shaft and the linkage mechanism. The linkage mechanism includes: A push-pull rod, which is pivotally connected to the inner cavity of the shaft cylinder; A first pendulum and a second pendulum are arranged radially spaced along the drill bit body. The first end of each of the first pendulum and the second pendulum is slidably connected to the push-pull rod along the radial direction of the drill bit body. The second end of each of the first pendulum and the second pendulum is pivotally connected to the drill bit body. The first pendulum, the drill bit body, the second pendulum, and the push-pull rod form a quadrilateral unit. A locking assembly capable of locking the push-pull rod and the inner cavity of the shaft cylinder when the push-pull rod is pivoted to any position relative to the inner cavity of the shaft cylinder.

2. The jet drill bit for directional fracturing in coal mines according to claim 1, characterized in that, Both the first and second rocker arms include a support portion and a pressing portion that are pivotally connected to each other. The end of the support portion opposite to the pressing portion is pivotally connected to the drill bit body. The end of the pressing portion opposite to the support portion is slidably connected to the push-pull rod along the radial direction of the drill bit body. The pressing portion is slidably connected to the shaft cylinder along the first direction.

3. The jet drill bit for directional fracturing in coal mines according to claim 1, characterized in that, The linkage mechanism further includes a drive component, which is located in the inner cavity of the shaft cylinder. The drive component is connected to the push-pull rod so that the push-pull rod can rotate relative to the shaft cylinder.

4. The jet drill bit for directional fracturing in coal mines according to claim 3, characterized in that, The driving component includes: A telescopic cylinder, wherein the cylinder body of the telescopic cylinder is connected to the inner cavity of the shaft cylinder; The push box is connected to the telescopic rod of the telescopic cylinder to push and pull the push box relative to the shaft cylinder to move in the first direction. The side of the push box away from the telescopic cylinder is connected to the push-pull rod so that the push-pull rod can rotate relative to the shaft cylinder.

5. The jet drill bit for directional fracturing in coal mines according to claim 4, characterized in that, The inner wall of the shaft cylinder is provided with a positioning groove, and the locking assembly includes a positioning block. The positioning block is slidably connected to the push box along the radial direction of the drill bit body. The positioning block has a locking position that cooperates with the positioning groove and an unlocking position that is spaced apart from the positioning groove. The positioning slots are at least one and are arranged at intervals along the first direction.

6. The jet drill bit for directional fracturing in coal mines according to claim 5, characterized in that, The positioning block has a guide surface facing the positioning groove. When the positioning block switches between the locked position and the unlocked position, the guide surface is movably connected to the positioning groove along a second direction, which forms an angle with both the first direction and the radial direction of the drill bit body.

7. The jet drill bit for directional fracturing in coal mines according to claim 5, characterized in that, The push box has a receiving cavity, and the positioning block is slidably connected to the receiving cavity along the radial direction of the drill bit body. When the positioning block is switched from the locked position to the unlocked position, the positioning block is completely located in the receiving cavity.

8. The jet drill bit for directional fracturing in coal mines according to claim 7, characterized in that, The locking assembly further includes: A movable plate and a connecting rod, wherein the movable plate is disposed in the receiving cavity, the first end of the connecting rod is pivotally connected to the movable plate, and the second end of the connecting rod is pivotally connected to the positioning block; The movable plate has a first position and a second position. When the positioning block switches from the locked position to the unlocked position, the movable plate can slide relative to the receiving cavity from the first position to the second position along the first direction. An elastic element is provided, which is sandwiched between the movable plate and the inner wall of the receiving cavity and is capable of pressing the movable plate toward the second position.

9. The jet drill bit for directional fracturing in coal mines according to claim 7, characterized in that, The drive assembly further includes a pressing plate disposed in the receiving cavity and arranged with the moving plate along the first direction, wherein the pressing plate is closer to the push-pull rod than the moving plate; At least a portion of the telescopic rod of the telescopic cylinder is located in the receiving cavity and is slidably connected to the receiving cavity along the first direction. The extrusion plate is connected to the telescopic rod of the telescopic cylinder and is capable of sliding relative to the receiving cavity along the first direction to drive the push box or the moving plate.

10. The jet drill bit for directional fracturing in coal mines according to any one of claims 1-9, characterized in that, The drill bit body is provided with a jet nozzle, and the jet drill bit further includes: A conveying pipe is provided in the inner cavity of the shaft cylinder and located on the outer periphery of the linkage mechanism. The inlet of the conveying pipe is adapted to be connected to the external high-pressure water source. The manifold and connecting pipe are provided. The manifold is located between the drill bit body and the shaft. The outlet of the delivery pipe, the manifold, the connecting pipe and the jet nozzle are connected in sequence. The connecting pipe is a flexible pipe. The conveying pipes are at least one and are arranged at circumferential intervals along the shaft.

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