Rock-breaking PDC bit for hard conglomerate formations

Abstract

The present application relates to the technical field of PDC drill bit, and particularly relates to a rock breaking PDC drill bit for hard gravel stratum. The rock breaking PDC drill bit comprises a drill body, a water supply groove is formed through the drill body, a dredging mechanism is arranged in the water supply groove, the dredging mechanism comprises a plurality of mounting frames which are slidably connected in the water supply groove, a steel needle and a U-shaped frame are slidably connected in the mounting frames in a vertical direction, the steel needle is fixedly connected with the U-shaped frame, the U-shaped frame is assembled with a first compression spring on the inner wall of the mounting frame, and a driving mechanism for driving the steel needle to perform vertical impact movement is arranged in the drill body. When the water outlet is blocked by gravel, the pressure in the branch corresponding to the water supply groove is automatically increased to trigger the driving mechanism to control the action of the telescopic rod, the mounting frame is driven to slide radially so that the steel needle is aligned with the blocked position, and the steel needle is impacted downward to break the gravel in the water outlet, thereby realizing accurate positioning and dredging, preventing the pump from being blocked, and ensuring continuous drilling operation.

Description

Technical Field

[0001] This invention relates to the field of PDC drill bit technology, and more particularly to a rock-breaking PDC drill bit for hard gravel formations. Background Technology

[0002] PDC drill bits are widely used in oil and gas drilling due to their high cutting efficiency and fast drilling speed. However, when drilling in hard gravel formations, the following prominent problems exist: Firstly, the water supply tank in the drill body usually branches out into multiple outlets that penetrate the drill bit. These outlets are used to deliver high-pressure drilling fluid to the bottom of the drill bit to cool the cutting teeth and carry rock cuttings back up. During drilling in hard gravel formations, large gravel particles are very easy to embed or get stuck in the outlets, causing blockages and preventing the high-pressure drilling fluid from flowing out normally. At this time, the pressure in the water supply tank rises sharply, which can cause pump stalling in severe cases, forcing the drilling operation to be interrupted, affecting drilling efficiency, and even damaging the mud pump equipment.

[0003] Secondly, existing drill bits lack an active unblocking mechanism for outlet blockage. Once blocked, the only solutions are to pull out the drill bit and replace it or to use reverse circulation flushing, which is time-consuming, labor-intensive, and increases drilling costs.

[0004] To address the aforementioned problems, this invention provides a rock-breaking PDC drill bit for hard gravel formations, which aims to utilize the increased pressure in the water supply tank when the outlet is blocked to adaptively trigger the radial positioning and vertical impact of the steel needle, thereby achieving precise crushing and unblocking of the blocked gravel. Summary of the Invention

[0005] This invention addresses the problem that existing PDC drill bits are prone to pump blockage due to gravel clogging at the outlet in hard gravel formations, and lack an active unblocking mechanism. It provides a PDC drill bit that can adaptively trigger radial positioning and vertical impact unblocking using the blockage pressure.

[0006] The technical solution is as follows: A rock-breaking PDC drill bit for hard gravel formations includes a drill body with a water supply groove extending through it. It also includes a clearing mechanism located within the water supply groove. The clearing mechanism includes several mounting brackets slidably connected within the water supply groove. Each mounting bracket has a steel needle and a U-shaped frame slidably connected vertically through it. The steel needle is fixedly connected to the U-shaped frame. A first compression spring is fitted to the inner wall of the U-shaped frame and the mounting bracket. A driving mechanism for driving the steel needle to move vertically in impact is provided within the drill body. Several telescopic rods are fixedly installed within the water supply groove. A tension spring is fitted between the fixed end and the telescopic end of each telescopic rod. The telescopic ends of the telescopic rods are respectively fixedly connected to the mounting brackets via support plates.

[0007] Furthermore, a drying chamber is provided inside the drill body, and the driving mechanism includes an impact rod disposed inside the U-shaped frame. The impact rod slides through the water supply tank and extends into the drying chamber. A second compression spring is assembled between the impact rod and the inner wall of the drying chamber. A rectangular block is fixedly connected to the impact rod. Grooves are symmetrically provided on the U-shaped frame. A locking block that engages with the rectangular block is slidably connected in the groove. A third compression spring is assembled between the locking block and the groove.

[0008] Furthermore, a drive chamber is provided inside the drill body, and the drive mechanism also includes a pressure relief valve that connects the water supply tank and the drive chamber. The pressure relief valve is connected to the inner cavity of the fixed end of the telescopic rod. When the pressure of the water supply tank is abnormal, the pressure relief valve guides liquid to the inner cavity of the telescopic rod to adjust the pressure, thereby realizing the adaptive triggering of the radial sliding of the mounting frame.

[0009] Furthermore, the drive mechanism also includes an impeller rotatably connected inside the drive cavity. The impeller's shaft rotates through the drill body and extends into the drying cavity, and is fixedly connected to a reciprocating screw. The reciprocating screw is rotatably assembled inside the drying cavity. A drive block is threadedly connected to the reciprocating screw. An impact frame that cooperates with the top end of the impact rod is slidably sleeved on the outside of the drive block. A fourth compression spring is assembled between the impact frame and the inner wall of the drying cavity.

[0010] Furthermore, guide rods are symmetrically fixed inside the drying chamber, and the driving block is slidably sleeved on the outside of the two guide rods and vertically limited and slidable along the guide rods.

[0011] Furthermore, the impact frame has symmetrically opened sliding grooves inside, and wedges are slidably connected in the sliding grooves. A fifth compression spring is installed between the wedges and the groove wall. The drive block has symmetrically opened irregular grooves that match the wedges.

[0012] Furthermore, an unlocking rod is slidably connected inside the irregular groove, and a sixth compression spring is assembled between the unlocking rod and the driving block. The end of the unlocking rod presses against the end of the wedge block to unlock the wedge block.

[0013] Furthermore, a top block is symmetrically fixed inside the drying chamber, and the top block engages with the unlocking rod during the upward stroke to achieve automatic mechanical unlocking.

[0014] Furthermore, a convex shaft is fixedly connected to the card block, and an unlocking plate that slides and presses against the convex shaft is symmetrically fixed inside the mounting frame. When the mounting frame is radially reset, the card block is unlocked through the unlocking plate.

[0015] Furthermore, the bottom of the drill body is symmetrically provided with two drainage grooves that are connected to the drive cavity, and two protective plates are symmetrically fixed to them. The protective plates are located directly below the corresponding drainage grooves and are cup-shaped covers that bulge downwards. The protective plates are fixed to the bottom of the drill body through circumferentially distributed legs, and a lateral flow gap is formed between the legs.

[0016] The beneficial effects of this invention are as follows: 1. This invention, by setting up a dredging mechanism, when the outlet is blocked by gravel, the pressure in the corresponding branch of the water supply tank increases, automatically triggering the drive mechanism to control the telescopic rod to move, driving the mounting frame to slide radially so that the steel needle is aimed at the blockage position, and realizing the downward impact of the steel needle to break the gravel in the outlet, achieving precise positioning and dredging, effectively preventing pump blockage, and ensuring continuous drilling operations.

[0017] 2. This invention utilizes the hydraulic pressure of the high-pressure drilling fluid to drive the impeller to rotate, and then converts the rotational motion into reciprocating linear motion through a reciprocating screw, so as to realize the impact of the impact frame on the impact rod. It does not require an independent hydraulic or electric power source and has a compact structure.

[0018] 3. By placing key transmission components such as the impact rod, reciprocating screw, drive block, and impact frame inside the drying chamber, the present invention completely isolates them from the high-pressure drilling fluid in the water supply tank, effectively preventing the high-pressure drilling fluid from entering the drying chamber and ensuring that the impact frame can smoothly impact the impact rod.

[0019] 4. This invention uses a bowl-shaped protective plate installed below the drainage tank. The protective plate's front shielding and the reverse flow blocking effect of the radial jet of drilling fluid prevent hard gravel from falling into the drainage tank from below and causing blockage. This ensures the continuous and smooth discharge of high-pressure drilling fluid from the drive chamber and ensures the stable operation of the impeller and impact mechanism. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a partial structural cross-sectional view of the water supply tank branch, telescopic rod, and drive cavity area in this invention; Figure 3 This is a schematic diagram of the unblocking mechanism of the present invention; Figure 4 This is a partial structural diagram of the installation location of the pressure relief valve of the present invention; Figure 5 This is a schematic diagram of the structure of the impact frame of the present invention; Figure 6 This is a cross-sectional view of the internal wedge block and the irregular groove of the drive block of the impact frame of the present invention. Figure 7 This is a partial structural schematic diagram of the cooperation between the unlocking rod and the irregular groove of the present invention; Figure 8This is a schematic diagram of the structure of the mating position between the top block inside the drying chamber and the unlocking rod in this invention; Figure 9 This is a schematic diagram of the installation of the unlocking plate of the present invention; Figure 10 This is a schematic diagram of the structure of the drainage tank of the present invention; Figure 11 This is a schematic diagram of the installation of the protective plate of the present invention.

[0021] Reference numerals: 1_Drill body, 101_Water supply tank, 102_Outlet, 201_Mounting bracket, 202_Steel needle, 203_U-shaped bracket, 204_Telescopic rod, 205_Support plate, 301_Drying chamber, 302_Impact rod, 303_Rectangular block, 304_Clamping block, 401_Drive chamber, 402_Pressure relief valve, 501_Impeller, 502_Reciprocating screw, 503_Drive block, 504_Impact frame, 505_Guide rod, 601_Wedge block, 602_Irregular groove, 701_Unlocking rod, 801_Top block, 901_Piston shaft, 902_Unlocking plate, 1001_Drainage tank, 1002_Protective plate. Detailed Implementation

[0022] The invention will now be described more fully below with reference to the accompanying drawings, in which presently preferred embodiments of the invention are illustrated. However, the invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided for thoroughness and completeness and to fully convey the scope of the invention to those skilled in the art. Example 1

[0023] A rock-breaking PDC drill bit for hard gravel formations, such as Figures 1-3As shown, the system includes a drill body 1. An axially extending water supply tank 101 is formed inside the drill body 1. The upper end of the water supply tank 101 is connected to a high-pressure drilling fluid channel within the drill string (the drill string is prior art and is not shown in the figure; further details are omitted here). The water supply tank 101 branches into four outlets 102 penetrating the drill body 1, used to transport high-pressure drilling fluid to the cutting area at the bottom of the drill body 1. A clearing mechanism is also provided within the water supply tank 101. This mechanism includes four mounting brackets 201 slidably connected horizontally within the water supply tank 101, corresponding to the positions of the four outlets 102. Each mounting bracket 201 contains a steel needle 202 and a U-shaped bracket 203 slidably connected vertically. Specifically, the steel needle 202 is a slender cylindrical structure with a sharp lower end. A conical or wedge-shaped tip is used to impact and break up gravel blocking the outlet 102. The bottom of the U-shaped frame 203 is fixedly connected to the top of the steel needle 202. A first compression spring is installed between the bottom of the U-shaped frame 203 and the bottom of the inner wall of the mounting frame 201. The first compression spring is sleeved on the outside of the steel needle 202 and is used to apply an upward elastic thrust to the U-shaped frame 203. A drive mechanism is provided inside the drill body 1 to drive the steel needle 202 to perform vertical impact movement. Four telescopic rods 204 are fixedly installed on the inner wall of the water supply tank 101. A tension spring is provided between the fixed end and the telescopic end of the telescopic rod 204 to provide a reset tension for the telescopic rod 204. A support plate 205 is fixedly connected to the telescopic end of each telescopic rod 204. The support plate 205 is L-shaped and is fixedly connected to the corresponding mounting frame 201.

[0024] like Figure 2 and Figure 4 As shown, a drying chamber 301 is provided inside the drill body 1. The driving mechanism includes an impact rod 302 disposed inside the U-shaped frame 203. Its lower end extends out of the lower wall of the drying chamber 301 and into the water supply tank 101, and its upper end extends into the interior of the drying chamber 301. The impact rod 302 and the drill body 1 are slidably sealed together. A second compression spring is installed between the impact rod 302 and the inner wall of the drying chamber 301. A rectangular block 303 is fixedly connected to the bottom end of the impact rod 302. Grooves are symmetrically provided on the inner wall of the U-shaped frame 203. A locking block 304 is slidably connected in each groove. A third compression spring is installed between the locking block 304 and the groove.

[0025] like Figure 2 and Figure 4 As shown, a drive chamber 401 is provided inside the drill body 1. The drive mechanism also includes a pressure relief valve 402 that connects the water supply tank 101 and the drive chamber 401. Specifically, the inlet of the pressure relief valve 402 is connected to the inside of the water supply tank 101, and the outlet of the pressure relief valve 402 is connected to the inner cavity of the fixed end of the telescopic rod 204 and the inside of the drive chamber 401. When the high-pressure drilling fluid in the water supply tank 101 cannot be discharged normally, the telescopic end of the telescopic rod 204 can be extended.

[0026] like Figure 2 , Figures 5-7 As shown, the drive mechanism also includes an impeller 501 rotatably connected inside the drive chamber 401. The high-pressure drilling fluid flowing out from the pressure relief valve 402 impacts the blades of the impeller 501, driving the impeller 501 to rotate. The shaft of the impeller 501 rotates upwards through the drive chamber 401 and extends into the drying chamber 301 to prevent the high-pressure drilling fluid in the drive chamber 401 from seeping into the drying chamber 301. A reciprocating screw 502 is fixedly connected to the top of the shaft of the impeller 501. The top of the reciprocating screw 502 is rotatably mounted inside the drying chamber 301. A drive block 503 is threadedly connected to the reciprocating screw 502. An impact frame 504 is slidably sleeved on the outside of the drive block 503. The impact frame 504 cooperates with the top of the impact rod 302. A fourth compression spring is installed between the top of the impact frame 504 and the inner wall of the drying chamber 301.

[0027] like Figure 5 and Figure 6 As shown, guide rods 505 are symmetrically fixed inside the drying chamber 301. The two guide rods 505 are symmetrically arranged relative to the reciprocating screw 502. The drive block 503 is slidably sleeved on the outside of the two guide rods 505. The drive block 503 slides vertically along the guide rods 505.

[0028] like Figure 6 and Figure 7 As shown, the impact frame 504 has symmetrically opened sliding grooves inside, and each sliding groove is slidably connected to a wedge 601. A fifth compression spring is installed between the wedge 601 and the sliding groove. The drive block 503 has symmetrically opened irregular grooves 602 that match the wedge 601. When the impact frame 504 moves to a specific position, the wedge 601 is embedded in the irregular groove 602 under the action of the fifth compression spring, thereby achieving axial locking between the impact frame 504 and the drive block 503.

[0029] like Figure 3 and Figure 7 As shown, an unlocking rod 701 is slidably connected inside the irregular groove 602. The top end of the unlocking rod 701 extends a certain length from the irregular groove 602. A sixth compression spring is assembled between the unlocking rod 701 and the drive block 503. When the unlocking rod 701 is subjected to a downward pushing force, the end of the unlocking rod 701 presses against the wedge block 601, pushing the wedge block 601 to overcome the elastic force of the fifth compression spring and exit from the irregular groove 602, thereby unlocking the wedge block 601 and releasing the locking relationship between the impact frame 504 and the drive block 503.

[0030] like Figure 8As shown, a top block 801 is symmetrically fixed inside the drying chamber 301. When the drive block 503 moves upward along the reciprocating screw 502 to near the top dead center, the top end of the unlocking rod 701 contacts the bottom end of the top block 801. As the drive block 503 continues to move upward, the top block 801 presses against the upward-moving unlocking rod 701. The top block 801 applies a downward thrust to the unlocking rod 701, pushing the unlocking rod 701 to slide downward, thereby pushing the wedge block 601 out of the irregular groove 602.

[0031] like Figure 9 As shown, a convex shaft 901 is fixedly connected to the locking block 304, and an unlocking plate 902 is symmetrically fixed inside the mounting frame 201. The unlocking plate 902 and the convex shaft 901 slide and press together. When the impact frame 504 slides downward, it applies a downward force to the top of the impact rod 302. If the steel needle 202 fails to break the gravel in one impact, the high-pressure drilling fluid remains in the inner cavity of the telescopic rod 204. The telescopic rod 204 remains in the extended state, and the steel needle 202 is still aligned with the blocked outlet, waiting for the next impact until the steel needle 202 breaks the gravel. When the steel needle 202 breaks the gravel and the outlet 102 is unobstructed, the high-pressure drilling fluid is discharged smoothly and no longer enters the pressure relief valve 402. The pressure in the inner cavity of the telescopic rod 204 is then released, and the tension spring contracts, causing the telescopic end of the telescopic rod 204 to contract, driving the mounting frame 201 to reset. Furthermore, the unlocking plate 902, by pressing the convex shaft 901, causes the rectangular block 303 to disengage from the locking block 304.

[0032] like Figure 10 and Figure 11 As shown, the bottom of the drill body 1 is symmetrically perforated with two drainage channels 1001 that communicate with the drive chamber 401, and two protective plates 1002 are symmetrically fixed to them. The two protective plates 1002 are located directly below the two drainage channels 1001 and vertically cover the outlet of the drainage channels 1001. The protective plates 1002 are cup-shaped covers that bulge downwards. They are fixed to the bottom of the drill body 1 by several circumferentially distributed legs, and a lateral gap is formed between the legs for the drilling fluid to flow out radially. After the high-pressure drilling fluid is sprayed vertically downwards through the drainage channels 1001, it impacts the top surface of the protective plate 1002, turns into a radial flow, and flows out into the borehole through the lateral gap. The bottom of the protective plate 1002 is higher than the cutting position of the crown cutting teeth of the drill body 1. The protective plate 1002 will not have a strong collision with the hard gravel. The protective plate 1002 is used to prevent hard gravel from falling into the drainage channels 1001 from below and causing blockage.

[0033] In the initial state, the elastic force of the fourth compression spring is greater than that of the second compression spring, so that the impact frame 504 exerts downward pressure on the impact rod 302 under the action of the elastic force of the fourth compression spring, causing the second compression spring to be compressed and put into an energy storage state. The rectangular block 303 is located below the two locking blocks 304, and the two wedges 601 are respectively embedded in the two irregular grooves 602.

[0034] Under normal drilling conditions, the high-pressure drilling fluid is evenly distributed to the four outlets 102 through the water supply tank 101. The telescopic end of the telescopic rod 204 is in a contracted state under the action of the tension spring, and the steel needle 202 is retracted inside the mounting frame 201, which does not interfere with the normal flow of the high-pressure drilling fluid, so that the high-pressure drilling fluid in the water supply tank 101 can be discharged smoothly, completing the drill bit cooling and cuttings return. Each outlet 102 of the water supply tank 101 is unobstructed and the branch pressure of the water supply tank 101 is balanced. The pressure relief valve 402 is kept closed, and the unblocking mechanism and the impact mechanism are in a static state and do not participate in the work. The drill bit only relies on the rotation of the crown cutting teeth to complete the conventional rock breaking operation.

[0035] When any outlet 102 is blocked by hard gravel, the high-pressure drilling fluid in the branch of the water supply tank 101 cannot be discharged normally, and the internal pressure of the branch rises sharply. The high-pressure drilling fluid triggers the corresponding pressure relief valve 402 to open. After being diverted by the pressure relief valve 402, one path of the high-pressure drilling fluid flows into the inner cavity of the fixed end of the telescopic rod 204, pushing the telescopic end of the telescopic rod 204 to extend outward. The tension spring is stretched, and the telescopic end of the telescopic rod 204 drives the mounting bracket 201 to slide radially along the drill body 1 through the support plate 205, so that the steel needle 202 is precisely aligned with the blocked outlet 102. The other path enters the drive chamber 401 and impacts the impeller 501 to rotate. 1. The reciprocating screw 502 rotates synchronously. Under the action of the reciprocating screw 502, the drive block 503 slides upward along the two guide rods 505. The drive block 503 drives the two unlocking rods 701 to move upward. Since the two wedges 601 are respectively embedded in the corresponding irregular grooves 602, the impact frame 504 slides upward with the drive block 503. The fourth compression spring is compressed, and the downward pressing force of the impact frame 504 on the impact rod 302 gradually decreases. The second compression spring releases its stored elastic potential energy, causing the corresponding impact rod 302 to slide upward. The impact rod 302 drives the rectangular block 303 to move upward. Subsequently, the rectangular block 303 and... The lower inclined surfaces of the two corresponding locking blocks 304 contact and press, causing the locking blocks 304 to slide and retract into the groove of the U-shaped frame 203. The third compression spring contracts until the bottom of the rectangular block 303 aligns with the tops of the two locking blocks 304. The third compression spring releases, and the locking blocks 304 reset and lock the bottom surface of the rectangular block 303 under the action of the third compression spring. When the drive block 503 and the impact frame 504 continue to move upward to near the upper stop point, the two top blocks 801 contact the tops of the two unlocking rods 701 respectively and apply a pushing force to them. The unlocking rods 701 slide downward along the irregular groove 602, the sixth compression spring contracts, and the unlocking rods 701... The bottom end pushes the corresponding wedge 601 out of the irregular groove 602, the fifth compression spring contracts, the impact frame 504 and the drive block 503 are unlocked, the fourth compression spring is released and drives the impact frame 504 to slide downward, so that the impact frame 504 hits the top of the impact rod 302. The impact rod 302 drives the steel needle 202 to slide downward through the rectangular block 303, the locking block 304 and the U-shaped frame 203. The first compression spring contracts and causes the steel needle 202 to extend into the outlet 102 to impact the gravel. After the impact frame 504 slides downward until the wedge 601 is disengaged from the drive block 503, the fifth compression spring is released and pushes the wedge 601 to extend.

[0036] If the steel needle 202 successfully breaks the gravel, the outlet 102 becomes unobstructed, and the pressure in the branch of the water supply tank 101 returns to normal. The steel needle 202 and the U-shaped frame 203 have sufficient downward sliding stroke, allowing the convex shaft 901 on the locking block 304 to contact the inclined surface of the corresponding unlocking plate 902. The unlocking plate 902 pushes the locking block 304 to slide into the groove of the U-shaped frame 203 via the convex shaft 901. The third compression spring contracts, and the locking block 304 no longer contacts the rectangular block 303, thus releasing the locking of the rectangular block 303. The first compression spring releases, causing the U-shaped frame 203 to move. Upon resetting, the U-shaped frame 203 drives the steel needle 202, the locking block 304, and the convex shaft 901 to move upwards and reset. At the same time, the third compression spring releases, causing the locking block 304 to extend out of the groove of the U-shaped frame 203 to complete the reset. The high-pressure drilling fluid is smoothly discharged and no longer enters the pressure relief valve 402. The pressure in the inner cavity of the telescopic rod 204 is released, and the tension spring contracts, causing the telescopic end of the telescopic rod 204 to contract, driving the mounting frame 201 to reset radially. At the same time, the high-pressure drilling fluid no longer enters the drive cavity 401, thereby causing the reciprocating screw 502 to stop rotating and the impact frame 504 to stop moving, thus completing the unblocking and resetting.

[0037] If the steel needle 202 fails to break the gravel, and the outlet 102 remains blocked, the pressure within the branch of the water supply tank 101 remains constant. The downward sliding stroke of the steel needle 202 and the U-shaped frame 203 is insufficient to allow the convex shaft 901 to contact the inclined surface of the unlocking plate 902. The locking block 304 maintains its hold on the rectangular block 303. The reciprocating screw 502 continues to rotate, driving the drive block 503 to descend. Once the drive block 503 enters the impact frame 504, the bottom end of the drive block 503 contacts the ends of the two wedges 601. The inclined surfaces make contact and push the two wedges 601 to slide. The fifth compression spring contracts, and then the wedges 601 align with the irregular grooves 602 of the drive block 503. Under the action of the fifth compression spring, they slide and embed into the irregular grooves 602, thereby locking the impact frame 504 and the drive block 503 again. Then the drive block 503 moves upward, which in turn causes the impact frame 504 to move upward and repeat the above steps to make the steel needle 202 continue to impact the gravel until the gravel is broken and the reset is completed.

[0038] As a further supplement, the high-pressure drilling fluid entering the drive chamber 401 is sprayed vertically downward through two drainage channels 1001, impacts the top surface of the corresponding protective plate 1002, and then turns into radial flow, flowing out into the borehole from the lateral gap between the protective plate 1002 and the bottom of the drill body 1; the protective plate 1002 blocks the outlet of the drainage channel 1001 in the vertical direction to prevent hard gravel from falling into the drainage channel 1001 from below and causing blockage.

[0039] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A rock-breaking PDC drill bit for hard gravel formations, comprising a drill body (1), wherein a water supply groove (101) is provided through the drill body (1), characterized in that: It also includes a dredging mechanism located in the water supply tank (101). The dredging mechanism includes several mounting brackets (201) slidably connected in the water supply tank (101). Each of the mounting brackets (201) has a steel needle (202) and a U-shaped frame (203) slidably connected in a vertical direction. The steel needle (202) is fixedly connected to the U-shaped frame (203). The U-shaped frame (203) and the inner wall of the mounting bracket (201) are equipped with a first compression spring. The drill body (1) is provided with a driving mechanism for driving the steel needle (202) to move vertically. Several telescopic rods (204) are fixedly installed in the water supply tank (101). A tension spring is installed between the fixed end and the telescopic end of the telescopic rod (204). The telescopic ends of the several telescopic rods (204) are respectively fixedly connected to the several mounting brackets (201) through support plates (205).

2. The rock-breaking PDC drill bit for hard gravel formations according to claim 1, characterized in that: The drill body (1) has a drying chamber (301) inside. The driving mechanism includes an impact rod (302) disposed inside the U-shaped frame (203). The impact rod (302) slides through the water supply tank (101) and extends into the drying chamber (301). A second compression spring is installed between the impact rod (302) and the inner wall of the drying chamber (301). A rectangular block (303) is fixedly connected to the impact rod (302). Grooves are symmetrically provided on the U-shaped frame (203). A locking block (304) that engages with the rectangular block (303) is slidably connected in the groove. A third compression spring is installed between the locking block (304) and the groove.

3. The rock-breaking PDC drill bit for hard gravel formations according to claim 2, characterized in that: The drill body (1) has a drive chamber (401) inside. The drive mechanism also includes a pressure relief valve (402) that connects the water supply tank (101) and the drive chamber (401). The pressure relief valve (402) is connected to the inner cavity of the fixed end of the telescopic rod (204). When the pressure of the water supply tank (101) is abnormal, the pressure relief valve (402) guides the liquid to the inner cavity of the telescopic rod (204) to adjust the pressure, thereby realizing the adaptive triggering of the radial sliding of the mounting bracket (201).

4. The rock-breaking PDC drill bit for hard gravel formations according to claim 3, characterized in that: The drive mechanism also includes an impeller (501) rotatably connected inside the drive cavity (401). The impeller (501) shaft rotates through the drill body (1) and extends into the drying cavity (301), and is fixedly connected to a reciprocating screw (502). The reciprocating screw (502) is rotatably assembled inside the drying cavity (301). A drive block (503) is threaded onto the reciprocating screw (502). An impact frame (504) that cooperates with the top end of the impact rod (302) is slidably sleeved on the outside of the drive block (503). A fourth compression spring is assembled between the impact frame (504) and the inner wall of the drying cavity (301).

5. The rock-breaking PDC drill bit for hard gravel formations according to claim 4, characterized in that: The drying chamber (301) is symmetrically fixed with guide rods (505), and the driving block (503) is slidably sleeved on the outside of the two guide rods (505) and vertically limited and slidable along the guide rods (505).

6. The rock-breaking PDC drill bit for hard gravel formations according to claim 4, characterized in that: The impact frame (504) has symmetrically opened sliding grooves inside, and a wedge (601) is slidably connected in the sliding groove. A fifth compression spring is installed between the wedge (601) and the groove wall. The drive block (503) has symmetrically opened irregular grooves (602) that match the wedge (601).

7. The rock-breaking PDC drill bit for hard gravel formations according to claim 6, characterized in that: An unlocking rod (701) is slidably connected inside the irregular groove (602). A sixth compression spring is assembled between the unlocking rod (701) and the drive block (503). The end of the unlocking rod (701) is pressed against the end of the wedge block (601) to unlock the wedge block (601).

8. The rock-breaking PDC drill bit for hard gravel formations according to claim 7, characterized in that: A top block (801) is symmetrically fixed inside the drying chamber (301). The top block (801) is pressed against the unlocking rod (701) during the upward stroke to achieve automatic mechanical unlocking.

9. The rock-breaking PDC drill bit for hard gravel formations according to claim 2, characterized in that: A convex shaft (901) is fixedly connected to the locking block (304), and an unlocking plate (902) that slides and presses against the convex shaft (901) is symmetrically fixed inside the mounting bracket (201). When the mounting bracket (201) is radially reset, the locking block (304) is unlocked by the unlocking plate (902).

10. A rock-breaking PDC drill bit for hard gravel formations according to claim 3, characterized in that: The bottom of the drill body (1) is symmetrically provided with two drainage grooves (1001) that are connected to the drive cavity (401), and two protective plates (1002) are symmetrically fixed to it. The protective plates (1002) are located directly below the corresponding drainage grooves (1001) and are cup-shaped covers that bulge downwards. The protective plates (1002) are fixed to the bottom of the drill body (1) through circumferentially distributed legs, and a lateral flow gap is formed between the legs.

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