A rotatable chip-cutter PDC bit

Abstract

The present application relates to the technical field of PDC drill bit, disclose a kind of rotatable chip tooth PDC drill bit, including drill bit main body, the lower surface of the drill bit main body is fixedly connected with connector, the drill bit main body is provided with main flow channel, the outer wall of the drill bit main body is fixedly connected with chip arm, the outer wall of the chip arm is provided with chip tooth mechanism, the chip tooth mechanism includes edge chip tooth and middle chip tooth, the edge chip tooth is fixedly connected in the outer wall of chip arm, the edge chip tooth is connected with transmission mechanism, the inside of the edge chip tooth and middle chip tooth is rotatably connected with shaft, the outer wall of the shaft is fixedly connected with composite sheet. The rotary power of adjacent chip tooth can be directly transmitted to jamming tooth by transmission chain, solve the problem that traditional fixed chip tooth and independent rotary chip tooth are prone to jamming, while synchronous rotation ensures that the wear rate of all edge composite sheets is completely consistent, avoid the drill bit to be scrapped in advance due to excessive wear of individual chip tooth.

Description

Technical Field

[0001] This invention relates to the field of PDC drill bit technology, specifically a rotatable chip-tooth PDC drill bit. Background Technology

[0002] Currently, in oil and gas drilling and geological drilling operations, PDC drill bits have become the core downhole tool for drilling hard formations, interlayers, and abrasive formations due to their advantages of high rock-breaking efficiency and good drilling stability. Conventional PDC drill bits mostly adopt a fixed, inlaid structure for their cutting teeth. The cutting teeth and drill bit wings are rigidly connected and assembled. During operation, the posture of the cutting teeth remains fixed, and rock breaking is completed solely by the rotation of the entire drill bit. This simple structure and convenient assembly make it suitable for basic construction needs in drilling homogeneous soft formations, and its application range is quite wide.

[0003] However, in actual deep well, directional well, and complex interbedded formation drilling conditions, the fixed cutting tooth structure reveals significant technical shortcomings. Interbedded soft and hard rock layers, gravel, and hard interlayers in the formation can generate instantaneous eccentric loads and jamming resistance on local cutting teeth. Fixed cutting teeth cannot adaptively unload this force, making them highly susceptible to tooth jamming, localized tooth breakage, and uneven wear of composite cutting teeth. Furthermore, each cutting tooth operates independently without any linkage. When a single cutting tooth becomes stuck, it cannot be freed with the help of surrounding teeth; it can only rely on increased torque in the drill string to forcibly break the resistance, which can easily cause drill bit vibration and drill string torque buildup. In severe cases, it can even lead to stuck drill pipe, buried drill string, and other downhole accidents, significantly reducing the safety and continuity of drilling operations. While some existing technologies feature rotatable PDC cutting teeth designs, most are single-tooth independent rotation structures, especially at the edges. Single-tooth rotation only improves the uniformity of wear within the tooth itself, failing to achieve load sharing and coordinated escape. When faced with sudden changes in formation hardness or high-resistance jamming conditions, it remains difficult to effectively avoid the problem of cutting teeth locking up. Particularly at the edges, relying solely on cutting friction for drive results in low linear velocity, hindering effective rotation and leading to uneven wear. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a rotatable chip-tooth PDC drill bit, which solves the problems of chip teeth locking and uneven wear when a single tooth at the edge rotates against a sudden hard point in the formation and under conditions of high resistance jamming.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a rotatable chip tooth PDC drill bit, comprising a drill bit body, a connector fixedly connected to the lower surface of the drill bit body, a main channel provided in the drill bit body, a nozzle fixedly connected inside the drill bit body, a chip arm fixedly connected to the outer wall of the drill bit body, a chip tooth mechanism provided on the outer wall of the chip arm, the chip tooth mechanism including edge chip teeth and middle chip teeth, the edge chip teeth fixedly connected to the outer wall of the chip arm, a transmission mechanism connected to the edge chip teeth, a rotating shaft rotatably connected inside both the edge chip teeth and the middle chip teeth, a composite plate fixedly connected to the outer wall of the rotating shaft, and the middle chip teeth connected inside the chip arm.

[0006] Preferably, the transmission mechanism includes a first gear and a transmission gear. The outer wall of the first gear is fixedly connected to the outer wall of the rotating shaft to which the edge cutting teeth belong. Adjacent first gears are meshed with transmission gears, and the transmission gears are rotatably connected inside the cutting arm.

[0007] Preferably, the central cutting tooth is fixedly connected inside the cutting arm.

[0008] Preferably, the central cutting tooth is slidably connected to the inside of the cutting arm, a slider is fixedly connected to the outer wall of the central cutting tooth, a limiting cavity is formed inside the cutting arm, and the outer wall of the slider is slidably connected to the inside of the limiting cavity.

[0009] Preferably, the inner wall of the cutting arm is provided with a flow channel, one end of which is connected to the limiting cavity and the other end of which is connected to the main flow channel.

[0010] Preferably, an auxiliary nozzle is fixedly connected inside the chip arm, and the chip arm has a drainage channel, a water inlet channel, and a connection port inside. The connection port connects the auxiliary nozzle and the drainage channel, the drainage channel connects the connection port and the water inlet channel, and the water inlet channel connects the drainage channel and the main channel.

[0011] Preferably, one of the gears is connected to a transmission mechanism, a slide rod is slidably connected inside the chip arm, and balls are fixedly connected to both ends of the slide rod. The transmission mechanism is connected to one of the balls, and the other ball is slidably connected inside the drainage channel.

[0012] Preferably, the transmission mechanism includes a second gear, the tooth end of the second gear meshing with the tooth end of the first gear, an eccentric wheel fixedly connected to the outer wall of the second gear, the second gear being rotatably connected inside the chip arm, and the outer wall of the eccentric wheel conforming to the outer wall of the sphere.

[0013] Preferably, the composite sheet comprises a polycrystalline diamond layer and a cemented carbide substrate. The cemented carbide substrate is subjected to a cobalt removal treatment to form a cobalt-removed layer. The cobalt-removed layer is filled with a ceramic self-lubricating material driven by extreme pressure. The ceramic self-lubricating material is selected from at least one of molybdenum disulfide, tungsten diselenide, or graphite-like carbon.

[0014] Preferably, the surface of the composite sheet is deposited with a composite coating, which includes a first coating, a second coating and a third coating arranged sequentially from the inside to the outside. The first coating is a Ti / TiN transition layer, the second coating is a multilayer alternating structure formed by alternating deposition of TiCN hard coating and MoS2 / C soft coating, with the alternating deposition number being 2 to 4 times, and the third coating is an amorphous alloy coating or a high-entropy amorphous alloy coating.

[0015] This invention provides a rotatable chip-tooth PDC drill bit. It has the following beneficial effects: 1. This invention achieves forced synchronous rotation of all edge cutting teeth through the meshing transmission of adjacent cutting tooth shaft gears and intermediate transmission gears. When a single cutting tooth encounters instantaneous high resistance while cutting hard rock, the rotational power of adjacent cutting teeth can be directly transmitted to the stuck teeth through the transmission chain, solving the problem of easy drill jamming caused by traditional fixed cutting teeth and independently rotating cutting teeth; at the same time, synchronous rotation ensures that the wear rate of all edge composite plates is completely consistent, avoiding premature drill bit failure due to excessive wear of individual cutting teeth.

[0016] 2. When the middle cutting tooth encounters hard interlayer or gravel impact, it can automatically retract into the cutting arm along the frustum-shaped guide surface. The impact load is passively buffered through the structural gap, which significantly reduces the failure rate of the middle cutting tooth breaking or fracture.

[0017] 3. This invention utilizes a dedicated flow channel connecting the main flow channel and the limiting cavity within the cutting arm to directly convert the system pressure of the drilling fluid into the thrust of the central cutting teeth. As the drilling fluid pressure automatically changes with drilling depth and formation conditions, the extension of the central cutting teeth can be adaptively adjusted synchronously, always maintaining the optimal cutting angle and cutting depth, which can significantly improve the drilling speed in complex formations.

[0018] 4. This invention utilizes the power generated by the rotation of the cutting teeth to periodically block the drainage path through a gear-eccentric wheel-slide rod-ball mechanism, generating pulsed water flow without the need for an additional power unit. The pulse frequency perfectly matches the cutting frequency of the cutting teeth, generating a stronger jet impact force, effectively removing sticky rock chips adhering to the surface of the cutting teeth and the gaps between the cutting arms; simultaneously, the auxiliary nozzle provides directional cooling to the sides and root areas of the cutting teeth that the main nozzle cannot cover, eliminating cooling blind spots and significantly reducing the operating temperature of the cutting teeth.

[0019] 5. The ceramic self-lubricating material of this invention continuously precipitates as the substrate wears during cutting, forming a stable self-lubricating film at the interface between the composite sheet and the rock. This reduces the coefficient of friction and cutting temperature from within the material, unlike traditional methods that only coat the surface with a lubricating coating, which is prone to wear and peeling. This invention achieves a continuous self-lubricating effect from the surface to the interior of the composite sheet, significantly improving its wear resistance and resistance to thermal damage. The Ti / TiN transition layer ensures high bonding strength between the coating and the substrate, preventing coating peeling. The alternating soft and hard layers combine excellent wear resistance and self-lubricating properties. The outermost amorphous alloy coating provides excellent corrosion resistance and impact resistance, enabling the composite sheet to maintain long-term stable cutting performance in complex formations containing corrosive media. Attached Figure Description

[0020] Figure 1 This is a perspective view of the present invention; Figure 2 This is a cross-sectional schematic diagram of the internal structure of the chip arm of the present invention; Figure 3 This is a cross-sectional schematic diagram of the internal structure of the edge chipping teeth of the present invention; Figure 4 This is a schematic diagram of a partial structure of the slider of the present invention; Figure 5 This is a partial structural diagram of the limiting cavity of the present invention; Figure 6 for Figure 5 Enlarged view of point A in the middle; Figure 7 This is a partial structural diagram of the auxiliary nozzle of the present invention; Figure 8 This is a partial structural diagram of the composite sheet of the present invention; Figure 9 This is a partial structural diagram of the eccentric wheel of the present invention; Figure 10 Figure 9 Enlarged diagram of point B in the middle.

[0021] The components are as follows: 1. Drill bit body; 2. Connector; 3. Nozzle; 4. Chip arm; 5. Chip tooth mechanism; 501. Edge chip tooth; 502. Center chip tooth; 503. Rotating shaft; 504. Composite plate; 6. Transmission mechanism; 601. Gear one; 602. Transmission gear; 7. Slider; 8. Limiting cavity; 9. Flow channel; 10. Auxiliary nozzle; 11. Gear two; 12. Eccentric wheel; 13. Ball; 14. Drainage channel; 15. Water inlet channel; 16. Slide rod; 17. Connector. Detailed Implementation

[0022] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] Example 1

[0024] Please see the appendix Figure 1 - Appendix Figure 10 This invention provides a rotatable chip-tooth PDC drill bit, comprising a drill bit body 1, a connector 2 fixedly connected to the lower surface of the drill bit body 1, a main channel provided in the drill bit body 1, a nozzle 3 fixedly connected inside the drill bit body 1, a chip arm 4 fixedly connected to the outer wall of the drill bit body 1, a chip tooth mechanism 5 provided on the outer wall of the chip arm 4, the chip tooth mechanism 5 including edge chip teeth 501 and middle chip teeth 502, the edge chip teeth 501 fixedly connected to the outer wall of the chip arm 4, a transmission mechanism 6 connected to the edge chip teeth 501, a rotating shaft 503 rotatably connected inside both the edge chip teeth 501 and the middle chip teeth 502, a composite plate 504 fixedly connected to the outer wall of the rotating shaft 503, and the middle chip teeth 502 connected inside the chip arm 4.

[0025] Specifically, the transmission mechanism 6 is used to prevent the edge cutting teeth 501 from getting stuck. The composite plate 504 and the rotating shaft 503 are equipped with anti-disengagement features. The edge cutting teeth 501 and the middle cutting teeth 502 support the rotation of the rotating shaft 503. A connector 2 is fixedly connected to the lower surface of the drill bit body 1. The outer wall of the connector 2 is provided with standard API drill pipe threads for connecting the drill bit to the drill string. The drill bit body 1 has a main channel inside, which extends along the axis of the drill bit body 1. The upper end of the main channel is connected to the water eye inside the drill string, and the lower end of the main channel branches into multiple branch channels. The drill bit body 1 has nozzles 3 fixedly connected inside. The number of nozzles 3 is the same as the number of branch channels. Each nozzle 3 is connected to a branch channel. The outlet of the nozzle 3 faces the cutting surface of the drill bit and is used to spray drilling fluid into the cutting area to achieve cooling and chip removal functions. A cutting arm 4 is fixedly connected to the outer wall of the drill bit body 1. There are three to six cutting arms 4, evenly distributed along the circumference of the drill bit body 1. The cross-sectional shape of the cutting arm 4 is trapezoidal, providing high structural strength and resistance to deformation. A cutting tooth mechanism 5 is provided on the outer wall of the cutting arm 4, used for cutting and breaking the rock. The cutting tooth mechanism 5 includes edge cutting teeth 501 and central cutting teeth 502. The edge cutting teeth 501 are fixedly connected to the outer wall of the cutting arm 4, located at the outer edge of the cutting arm 4, and are mainly responsible for cutting the outer rock of the wellbore. A transmission mechanism 6 is connected to the edge cutting teeth 501, which drives the edge cutting teeth 501 to rotate, preventing them from getting stuck when cutting hard rock. The rotating shaft 503 is made of high-strength wear-resistant alloy steel, and its surface is hardened, providing high hardness and wear resistance. A composite plate 504 is fixedly connected to the outer wall of the rotating shaft 503. The composite plate 504 and the rotating shaft 503 are connected by an interference fit, resulting in high connection strength and the ability to withstand large cutting torques. The composite plate 504 and the rotating shaft 503 are equipped with an anti-disengagement structure, which includes an annular boss at the end of the rotating shaft 503 and an annular groove inside the cutting teeth. The annular boss is embedded in the annular groove, effectively preventing the rotating shaft 503 and the composite plate 504 from disengaging from the cutting teeth during operation. The edge cutting teeth 501 and the middle cutting teeth 502 support the rotation of the rotating shaft 503. Bearing seats are provided inside the edge cutting teeth 501 and the middle cutting teeth 502, and sliding bearings are installed inside the bearing seats. The sliding bearings are sleeved on the outer wall of the rotating shaft 503, reducing the frictional resistance during rotation and improving the rotational flexibility of the rotating shaft 503. The central cutting tooth 502 is connected inside the cutting arm 4. The central cutting tooth 502 is located in the middle of the cutting arm 4 and is mainly responsible for cutting the rock in the central area of ​​the wellbore.The transmission mechanism 6 of this application enables the synchronous rotation of all edge cutting teeth 501. When a single edge cutting tooth 501 encounters significant resistance due to cutting hard rock, the rotational power of adjacent edge cutting teeth 501 is transmitted to that cutting tooth through the transmission gear 602, helping it overcome the resistance and continue rotating. This solves the problem of traditional fixed cutting teeth easily getting stuck, significantly reducing the incidence of drill bit jamming accidents. Furthermore, the synchronously rotating edge cutting teeth 501 ensure that the wear rate of all composite plates 504 is consistent, assisting in the grinding process while preventing the entire drill bit from being prematurely scrapped due to excessive wear of individual cutting teeth, thus extending the overall service life of the drill bit.

[0026] The transmission mechanism 6 includes a gear 601 and a transmission gear 602. The outer wall of the gear 601 is fixedly connected to the outer wall of the rotating shaft 503 to which the edge cutting tooth 501 belongs. The transmission gear 602 is meshed between adjacent gears 601 and is rotatably connected inside the cutting arm 4.

[0027] Specifically, the outer wall of gear 601 is fixedly connected to the outer wall of the rotating shaft 503 to which the edge cutting tooth 501 belongs. Gear 601 and rotating shaft 503 are connected by a flat key, ensuring synchronous rotation of gear 601 and rotating shaft 503. A transmission gear 602 meshes between adjacent gears 601. The module and pressure angle of transmission gear 602 are the same as those of gear 601, ensuring smooth gear meshing. Transmission gear 602 is rotatably connected inside the cutting arm 4. The cutting arm 4 has a gear mounting cavity inside, and a gear shaft is fixedly connected inside the gear mounting cavity. Transmission gear 602 is sleeved on the outer wall of the gear shaft. A rolling bearing is installed between transmission gear 602 and gear shaft. The rolling bearing reduces the frictional resistance of transmission gear 602 during rotation, improving transmission efficiency. The cutting arm 4 supports the rotation of the transmission gear 602. The two ends of the gear shaft are fixedly connected to the inner walls of the gear mounting cavity on both sides. The gear shaft has sufficient rigidity and strength to withstand the radial and axial forces generated during transmission. When the edge cutting teeth 501 are cutting rock, the friction between the rock and the composite plate 504 causes the composite plate 504 and the rotating shaft 503 to rotate. The rotating shaft 503 drives the gear 601 to rotate, and the gear 601 drives the adjacent edge cutting teeth 501 to rotate synchronously through the transmission gear 602, thus achieving the coordinated rotation of all edge cutting teeth 501.

[0028] The middle cutting tooth 502 is fixedly connected to the inside of the cutting arm 4.

[0029] Specifically, in one basic embodiment, the housing of the central cutting tooth 502 is fixedly connected to the mounting hole of the cutting arm 4 by an interference fit or welding. The central cutting tooth 502 is located in the middle region of the crown of the cutting arm 4, between the edge cutting tooth 501 and the drill body 1. Due to its fixed connection, the shaft 503 of the central cutting tooth 502 can still rotate freely. This fixed connection method has a simple structure and is easy to process and assemble.

[0030] Example 2

[0031] The middle cutting tooth 502 is slidably connected to the inside of the cutting arm 4, and the outer wall of the middle cutting tooth 502 is fixedly connected to the slider 7. A limiting cavity 8 is opened inside the cutting arm 4, and the outer wall of the slider 7 is slidably connected to the inside of the limiting cavity 8.

[0032] Specifically, in another embodiment of the present invention, the central cutting tooth 502 is slidably connected to the inside of the cutting arm 4. A slider 7 is fixedly connected to the outer wall of the central cutting tooth 502. The slider 7 is frustoconical, with its large-diameter end fixedly connected to the outer wall of the central cutting tooth 502 and its small-diameter end facing the inside of the cutting arm 4. A limiting cavity 8 is formed inside the cutting arm 4. The shape of the limiting cavity 8 is adapted to the shape of the slider 7. The large-diameter end of the limiting cavity 8 faces the outer wall of the cutting arm 4, and the small-diameter end faces the inside of the cutting arm 4. The outer wall of the slider 7 is slidably connected to the inside of the limiting cavity 8. The slider 7 and the limiting cavity 8 allow the central cutting tooth 502 to move slightly. When the central cutting tooth 502 encounters a hard interlayer, the central cutting tooth 502 can move slightly inward into the cutting arm 4, thereby buffering the impact load of the hard interlayer on the central cutting tooth 502, effectively preventing tooth breakage and improving the service life of the drill bit. When the middle cutting tooth 502 encounters a hard interlayer or gravel layer, it can automatically retract into the cutting arm 4, thereby effectively buffering the impact load of hard rock on the cutting tooth and significantly reducing the probability of the middle cutting tooth 502 chipping or breaking.

[0033] Example 3

[0034] The inner wall of the chip arm 4 is provided with a flow channel 9, one end of which is connected to the limiting cavity 8, and the other end of which is connected to the main flow channel.

[0035] Specifically, in another embodiment of the present invention, a flow channel 9 is formed on the inner wall of the cutting arm 4. The inner wall of the flow channel 9 is polished to reduce the resistance to the flow of drilling fluid. One end of the flow channel 9 is connected to the limiting cavity 8, and the connection between the flow channel 9 and the limiting cavity 8 is located at the bottom of the small-diameter end of the limiting cavity 8. The other end of the flow channel 9 is connected to the main flow channel, and the connection between the flow channel 9 and the main flow channel is located on the side wall of the main flow channel. When the drilling fluid flows inside the main flow channel, some of the drilling fluid will enter the limiting cavity 8 through the flow channel 9. When the water pressure is high, the thrust of the drilling fluid on the slider 7 will increase, thereby pushing the slider 7 and the middle cutting tooth 502 to extend outward from the cutting arm 4. The greater the pressure of the drilling fluid, the greater the extension of the middle cutting tooth 502. This ensures that the middle cutting tooth 502 always maintains a good cutting state.

[0036] Example 4

[0037] An auxiliary nozzle 10 is fixedly connected inside the chip arm 4. The chip arm 4 has a drainage channel 14, a water inlet channel 15, and a connection port 17. The connection port 17 connects the auxiliary nozzle 10 and the drainage channel 14. The drainage channel 14 connects the connection port 17 and the water inlet channel 15. The water inlet channel 15 connects the drainage channel 14 and the main channel.

[0038] Specifically, in another embodiment of the present invention, an auxiliary nozzle 10 is fixedly connected inside the cutting arm 4. Multiple auxiliary nozzles 10 are evenly distributed along the length of the cutting arm 4, with their outlets facing the cutting surface of the cutting tooth mechanism 5. The cutting arm 4 has a drainage channel 14, a water inlet channel 15, and a connection port 17 inside. One end of the water inlet channel 15 connects to the main channel, and the other end connects to the drainage channel 14. The diameter of the drainage channel 14 is the same as the diameter of the water inlet channel 15. One end of the drainage channel 14 connects to the water inlet channel 15, and the other end connects to the connection port 17. One end of the connection port 17 connects to the drainage channel 14, and the other end connects to the auxiliary nozzle 10. Drilling fluid enters the water inlet channel 15 from the main channel, then passes through the drainage channel 14 and the connection port 17 to reach the auxiliary nozzle 10, and finally is sprayed from the auxiliary nozzle 10 onto the cutting surface of the cutting tooth mechanism 5. The auxiliary nozzle 10 can provide auxiliary cooling and chip removal for the chip tooth mechanism 5, effectively reducing the working temperature of the chip tooth mechanism 5, and promptly removing the rock chips generated during cutting, preventing rock chips from accumulating around the chip teeth and affecting the cutting effect. It can also provide targeted cooling and chip removal for the sides and root areas of the chip teeth that cannot be covered by the main nozzle, eliminating blind spots in cooling and chip removal.

[0039] Gear 601 is connected to transmission mechanism 6. Inside chip arm 4, slide rod 16 is slidably connected. Both ends of slide rod 16 are fixedly connected to ball 13. Transmission mechanism 6 is connected to one of the balls 13. The other ball 13 is slidably connected inside drainage channel 14.

[0040] Specifically, gear 601 is connected to a transmission mechanism 6, and a slide rod 16 is slidably connected inside the cutting arm 4. The slide rod 16 is made of stainless steel, possessing excellent corrosion resistance and wear resistance. Balls 13, made of hard alloy, are fixedly connected to both ends of the slide rod 16, exhibiting high hardness and wear resistance. The transmission mechanism 6 connects to one ball 13, while the other ball 13 is slidably connected inside the drainage channel 14. The transmission mechanism 6 drives the slide rod 16 to reciprocate within the cutting arm 4, and the slide rod 16 drives the ball 13 to reciprocate within the drainage channel 14. During this reciprocating motion, the ball 13 periodically blocks the drainage channel 14, causing a periodic change in the drilling fluid flow rate within the drainage channel 14, forming a pulsed water path. This pulsed water path increases the injection pressure and impact force of the auxiliary nozzle 10, enhancing cooling and chip removal effects. Pulsed water flow has a stronger rock-clearing ability, effectively removing sticky rock cuttings adhering to the surface of the cutting teeth and between the cutting arms, preventing rock cuttings from forming mud bags, and ensuring the cutting efficiency of the drill bit. The pulse frequency is synchronized with the rotation speed of the cutting teeth, ensuring optimal pulse cooling and cuttings removal effects under different drilling parameters.

[0041] The transmission mechanism 6 includes a second gear 11, the tooth end of which is meshed with the tooth end of a first gear 601. An eccentric wheel 12 is fixedly connected to the outer wall of the second gear 11. The second gear 11 is rotatably connected to the inside of the cutting arm 4. The outer wall of the eccentric wheel 12 is in contact with the outer wall of the sphere 13.

[0042] Specifically, the transmission mechanism 6 includes a second gear 11. The module and pressure angle of the second gear 11 are the same as those of the first gear 601, and the tooth ends of the second gear 11 mesh with the tooth ends of the first gear 601. An eccentric wheel 12 is fixedly connected to the outer wall of the second gear 11. The second gear 11 is rotatably connected inside the chip arm 4, which has a second gear mounting cavity. A second gear shaft is fixedly connected inside the second gear mounting cavity, and the second gear 11 is fitted onto the outer wall of the second gear shaft. A rolling bearing is installed between the second gear 11 and the second gear shaft. The chip arm 4 supports the rotation of the second gear 11, and both ends of the second gear shaft are fixedly connected to the inner walls of the second gear mounting cavity on both sides. The outer wall of the eccentric wheel 12 fits against the outer wall of the sphere 13. The outer wall of the eccentric wheel 12 is polished to reduce the frictional resistance between the eccentric wheel 12 and the sphere 13. When gear 1 601 rotates, gear 1 601 drives gear 2 11 to rotate, and gear 2 11 drives eccentric wheel 12 to rotate synchronously. When eccentric wheel 12 rotates, it pushes ball 13 and slide rod 16 to move towards drainage channel 14. At the same time, the drilling fluid pressure inside water inlet channel 15 pushes ball 13 and slide rod 16 towards eccentric wheel 12, thereby realizing the reciprocating sliding of slide rod 16 and ball 13.

[0043] The composite sheet 504 includes a polycrystalline diamond layer and a cemented carbide substrate. The cemented carbide substrate is subjected to a cobalt removal treatment to form a cobalt removal layer. The cobalt removal layer is filled with a ceramic self-lubricating material driven by extreme pressure. The ceramic self-lubricating material is selected from at least one of molybdenum disulfide, tungsten diselenide, or graphite-like carbon.

[0044] Specifically, the composite sheet 504 comprises a polycrystalline diamond layer and a cemented carbide matrix. The polycrystalline diamond layer, located at the front end of the composite sheet 504, is the primary cutting layer. The cemented carbide matrix, located at the rear end of the composite sheet 504, supports the polycrystalline diamond layer. The cemented carbide matrix undergoes a cobalt-removal treatment to form a cobalt-removed layer, which is performed using an acid leaching method. A ceramic self-lubricating material is then filled into the cobalt-removed layer under extreme pressure. This extreme pressure filling process involves filling the pores of the cobalt-removed layer with the ceramic self-lubricating material under pressures of 5 GPa to 10 GPa and temperatures of 1000°C to 1500°C. The ceramic self-lubricating material is selected from at least one of molybdenum disulfide, tungsten diselenide, or graphite-like carbon. During operation, the ceramic self-lubricating material continuously precipitates, forming a self-lubricating film on the contact surface between the composite sheet 504 and the rock. This effectively reduces the coefficient of friction between the composite sheet 504 and the rock, lowers the cutting temperature, and improves the wear resistance and service life of the composite sheet 504.

[0045] The surface of the composite sheet 504 is deposited with a composite coating, which includes a first coating, a second coating and a third coating arranged sequentially from the inside to the outside. The first coating is a Ti / TiN transition layer, the second coating is a multilayer alternating structure formed by alternating deposition of TiCN hard coating and MoS2 / C soft coating, with the alternating deposition number being 2 to 4 times, and the third coating is an amorphous alloy coating or a high-entropy amorphous alloy coating.

[0046] Specifically, the surface of the composite sheet 504 is deposited with a composite coating. The composite coating comprises a first coating, a second coating, and a third coating arranged sequentially from the inside out. The first coating is a Ti / TiN transition layer with a thickness of 0.1 to 0.3 micrometers. This first coating is deposited using magnetron sputtering, which improves the bonding strength between the composite coating and the composite sheet 504 substrate. The second coating is a multi-layered alternating structure formed by alternating deposition of a TiCN hard coating and a MoS2 / C soft coating. The alternation deposition is performed 2 to 4 times. Each TiCN hard coating layer has a thickness of 0.2 to 0.4 micrometers, and each MoS2 / C soft coating layer has a thickness of 0.1 to 0.2 micrometers. The TiCN hard coating has high hardness and wear resistance, improving the wear resistance of the composite sheet 504, while the MoS2 / C soft coating has good self-lubricating properties, reducing the frictional resistance between the composite sheet 504 and the rock. The third coating is an amorphous alloy coating or a high-entropy amorphous alloy coating. The thickness of the third coating is 0.5 micrometers to 1 micrometer. The third coating is deposited using a laser cladding process and has high hardness, wear resistance and corrosion resistance, which can effectively protect the surface of the composite sheet 504 from wear and corrosion.

[0047] Furthermore, considering that high-viscosity mud or drilling fluid containing solid particles may intrude into the mechanical movement gaps, causing gear mechanisms, slide bars, or shafts to become stuck due to mud buildup, this invention incorporates protective designs based on existing conventional sealing and lubrication technologies.

[0048] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A rotatable chip-tooth PDC drill bit, comprising a drill bit body (1), a connector (2) fixedly connected to the lower surface of the drill bit body (1), a main channel provided in the drill bit body (1), a nozzle (3) fixedly connected inside the drill bit body (1), and a chip arm (4) fixedly connected to the outer wall of the drill bit body (1), characterized in that, The outer wall of the chip arm (4) is provided with a chip tooth mechanism (5), which includes edge chip teeth (501) and middle chip teeth (502). The edge chip teeth (501) are fixedly connected to the outer wall of the chip arm (4), and the edge chip teeth (501) are connected to a transmission mechanism (6). The inner walls of the edge chip teeth (501) and the middle chip teeth (502) are rotatably connected to a rotating shaft (503). The outer wall of the rotating shaft (503) is fixedly connected to a composite plate (504), and the middle chip teeth (502) are connected to the inner wall of the chip arm (4).

2. The rotatable chip-tooth PDC drill bit according to claim 1, characterized in that, The transmission mechanism (6) includes a gear (601) and a transmission gear (602). The outer wall of the gear (601) is fixedly connected to the outer wall of the rotating shaft (503) to which the edge cutting tooth (501) belongs. The transmission gear (602) is meshed between adjacent gears (601) and the transmission gear (602) is rotatably connected inside the cutting arm (4).

3. A rotatable chip-tooth PDC drill bit according to claim 2, characterized in that, The central cutting tooth (502) is fixedly connected to the inside of the cutting arm (4).

4. A rotatable chip-tooth PDC drill bit according to claim 2, characterized in that, The central cutting tooth (502) is slidably connected to the inside of the cutting arm (4), and a slider (7) is fixedly connected to the outer wall of the central cutting tooth (502). A limiting cavity (8) is opened inside the cutting arm (4), and the outer wall of the slider (7) is slidably connected to the inside of the limiting cavity (8).

5. A rotatable chip-tooth PDC drill bit according to claim 4, characterized in that, The inner wall of the cutting arm (4) is provided with a flow channel (9), one end of the flow channel (9) is connected to the limiting cavity (8), and the other end of the flow channel (9) is connected to the main flow channel.

6. A rotatable chip-tooth PDC drill bit according to claim 2, characterized in that, An auxiliary nozzle (10) is fixedly connected inside the chip arm (4). The chip arm (4) has a drainage channel (14), a water inlet channel (15), and a connection port (17). The connection port (17) connects the auxiliary nozzle (10) and the drainage channel (14). The drainage channel (14) connects the connection port (17) and the water inlet channel (15). The water inlet channel (15) connects the drainage channel (14) and the main channel.

7. A rotatable chip-tooth PDC drill bit according to claim 6, characterized in that, The gear (601) is connected to a transmission mechanism (6), and a slide rod (16) is slidably connected inside the chip arm (4). Balls (13) are fixedly connected to both ends of the slide rod (16). The transmission mechanism (6) is connected to one of the balls (13), and the other ball (13) is slidably connected inside the drainage channel (14).

8. A rotatable chip-tooth PDC drill bit according to claim 7, characterized in that, The transmission mechanism (6) includes a second gear (11), the tooth end of the second gear (11) is meshed with the tooth end of the first gear (601), an eccentric wheel (12) is fixedly connected to the outer wall of the second gear (11), the second gear (11) is rotatably connected to the inside of the chip arm (4), and the outer wall of the eccentric wheel (12) is in contact with the outer wall of the sphere (13).

9. A rotatable chip-tooth PDC drill bit according to claim 1, characterized in that, The composite sheet (504) includes a polycrystalline diamond layer and a cemented carbide substrate. The cemented carbide substrate is subjected to a cobalt removal treatment to form a cobalt removal layer. The cobalt removal layer is filled with a ceramic self-lubricating material driven by extreme pressure. The ceramic self-lubricating material is selected from at least one of molybdenum disulfide, tungsten diselenide, or graphite-like carbon.

10. A rotatable chip-tooth PDC drill bit according to claim 9, characterized in that, The composite sheet (504) has a composite coating deposited on its surface. The composite coating includes a first coating, a second coating and a third coating arranged sequentially from the inside to the outside. The first coating is a Ti / TiN transition layer. The second coating is a multilayer alternating structure formed by alternating deposition of TiCN hard coating and MoS2 / C soft coating, with the alternating deposition number being 2 to 4 times. The third coating is an amorphous alloy coating or a high-entropy amorphous alloy coating.

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