A polycrystalline diamond compact cutting tooth and a high-efficiency high-bearing drill

Abstract

The utility model discloses a kind of polycrystalline diamond composite cutting teeth and high-efficiency high bearing drill, cutting tooth includes hard alloy base body and polycrystalline diamond layer, hard alloy base body is connected by the arc surface portion of two ends and the straight surface portion between two arc surface portion and is made into capsule-shaped column structure;The end face of polycrystalline diamond layer away from alloy base body is working surface, working surface is plane or is equipped with at least one convex portion;Convex portion includes upper end portion and the transition surface between it and arc surface portion and / or straight surface portion;The layout of cutting tooth is optimized by straight edge design in the application, innovative "capsule-shaped" composite cutting tooth design is introduced, and the failure problem of high bearing drill in restricted space is systematically solved under the tooth distribution bottleneck and hard rock working condition. Cutting tooth of straight edge design can realize higher tooth distribution density, so that drill can effectively distribute load in narrow space, thereby significantly improve the cutting performance of key area, improve overall drilling efficiency.

Description

Technical Field

[0001] This utility model relates to the field of superhard composite material technology, and in particular to a polycrystalline diamond composite cutting tooth and a high-efficiency, high-load-bearing drill bit. Background Technology

[0002] Currently, polycrystalline diamond composite (PDC) drill bits are widely used in oil and gas drilling, coalfield drilling, and geological exploration due to their significant advantages of high drilling speed and long service life. Especially in oil and gas drilling, PDC drill bits have a very high international market share. However, harsh working conditions such as hard and abrasive formations, heterogeneous formations, interbedded formations, or drilling requiring high drilling pressure (such as in certain directional well sections) significantly limit the drilling efficiency of PDC drill bits, with rapid wear of the cutting teeth constituting a key limiting factor.

[0003] Data shows that most PDC drill bit failures are primarily due to the degradation of cutting tooth performance, particularly in the wear and fracture of cutting teeth in the inner cone and crown regions. Current PDC drill bit designs exhibit relatively low tooth density in the inner cone and crown regions, causing individual cutting teeth in these areas to bear significantly increased loads during rock breaking. This excessively high single-tooth load easily leads to abnormal wear and fracture failure of the cutting teeth, becoming a key factor limiting the overall service life of the drill bit. Furthermore, due to the inherently narrow spatial structure of the crown and inner cone regions, the widely used cylindrical polycrystalline diamond composite cutting teeth, constrained by their geometry, cannot achieve high-density arrangement in these critical areas, objectively limiting the improvement of tooth density. Utility Model Content

[0004] Therefore, in order to solve the problems existing in the prior art, one of the objectives of this utility model is to provide a polycrystalline diamond composite cutting tooth.

[0005] The second objective of this invention is to provide a high-efficiency, high-load-bearing drill bit comprising polycrystalline diamond composite cutting teeth.

[0006] To achieve one of the above objectives, this utility model provides the following technical solution:

[0007] A polycrystalline diamond composite cutting tooth includes a cemented carbide substrate and a polycrystalline diamond layer bonded to the cemented carbide substrate. The cemented carbide substrate is composed of two arc-shaped surfaces at both ends and a straight surface between the two arc-shaped surfaces to form a capsule-like column structure. The end face of the polycrystalline diamond layer away from the cemented carbide substrate is the working surface, which is either flat or has at least one protrusion. The protrusion includes an upper end and a transition surface between it and the arc-shaped and / or straight surfaces.

[0008] To further explain, the diameter of the arc of the cross-section of the curved part is 5-30mm, and the length of the straight side of the cross-section of the straight part is 1 / 3-5 / 6 of the diameter of the arc.

[0009] To further explain, the arc lengths of the circular arcs in the cross-sections of the two curved surfaces are different, and the same end of the straight edge of the cross-sections of the two straight surfaces is close to or far from each other.

[0010] To further explain, the upper end portion has a planar or convex curved surface structure, and the edge of the upper end portion slopes downward toward the top edge of the straight portion and / or the two curved portions at both ends, forming the transition surface.

[0011] To further explain, the upper end portion is located above the central axis of the working surface of the polycrystalline diamond layer and extends toward the arc-shaped surface along the central axis direction; the edge of the upper end portion forms two transition surfaces between the top edges of the two straight surfaces.

[0012] To further explain, the upper end is located above the arc-shaped surface at one end of the working surface of the polycrystalline diamond layer, and the edge of the upper end forms three transition surfaces between the top edges of the arc-shaped surface and the straight surfaces on both sides at the other end.

[0013] To further explain, the upper end is located above the center of the working surface of the polycrystalline diamond layer, and four transition surfaces are formed between the edge of the upper end and the top edges of the two curved surfaces and the two straight surfaces.

[0014] To further explain, the transition surface is a concave or convex curved surface, and a chamfer is provided between the top edge of the transition surface and the top edge of the curved or straight surface.

[0015] To achieve the second objective mentioned above, this utility model provides the following technical solution:

[0016] A high-efficiency, high-load-bearing drill bit includes a drill bit body and a connector. The drill bit body has multiple cutting blades distributed on it. Each cutting blade has a diameter-maintaining area, a crown area, an inner cone area, and an outer cone area. The diameter-maintaining area has multiple columnar diameter-maintaining teeth. The crown area, the inner cone area, and the outer cone area are each provided with multiple polycrystalline diamond composite cutting teeth at intervals along the extension direction of the cutting blade.

[0017] To further explain, the drill bit body is also provided with a nozzle; the nozzle is used to form a drilling fluid passage; chip removal grooves are respectively provided between the two cutting blades; and connecting threads are provided on the outer periphery of the connector.

[0018] Compared with the prior art, the beneficial effects of this utility model are at least in the following aspects:

[0019] 1. This utility model's polycrystalline diamond composite cutting teeth optimize the layout of cutting teeth through a straight-edge design and introduce an innovative "capsule-shaped" composite cutting tooth design, systematically solving the bottleneck of tooth placement in confined spaces and the failure problem of high-load-bearing drill bits under hard rock conditions. The straight-edge design allows for the placement of more cutting teeth in space-constrained areas such as the crown area and inner cone area of ​​the drill bit, achieving a higher tooth density. This enables the drill bit to effectively distribute the load in a confined space, thereby significantly improving the cutting performance in critical areas and enhancing overall drilling efficiency.

[0020] Compared to traditional cylindrical cutting teeth, the optimized cutting tooth structure of this invention can increase the tooth density of the drill bit by 20%-50%. The increased density optimizes the load distribution, and the peak load per tooth decreases by 20%-35%, making the drill bit more adaptable to the harsh drilling conditions of high drilling pressure and high impact, thereby effectively improving rock breaking efficiency and drill bit service life.

[0021] 2. Furthermore, this invention optimizes the geometry of the cutting teeth, effectively improving the uniformity of load distribution through the design of the straight and curved surfaces. The addition of transition surfaces and a well-designed protrusion further enhances the structure, effectively reducing cutting tooth wear caused by overload. The transition surfaces between the protrusions and the curved and straight surfaces effectively alleviate stress concentration during cutting, preventing microscopic cracking and wear of the diamond layer, and extending the service life of the cutting teeth.

[0022] 3. The capsule-shaped cutting tooth structure of this utility model is a 180° rotatable symmetrical structure along its central axis. When the diamond layer at the working end wears to failure, it can be disassembled, rotated 180°, and re-brazed and fixed, using the original non-working end as an effective cutting surface, thus realizing the secondary use of the cutting tooth. This significantly reduces the replacement frequency of the cutting tooth, reduces maintenance costs and downtime in drilling operations, and ensures the continuous and efficient operation of the drill bit under complex geological conditions.

[0023] 4. The drill bit of this utility model achieves a high-density step tooth design through structural optimization of the cutting teeth, which greatly improves the load-bearing capacity and optimizes the load distribution, reducing the risk of damage to individual cutting teeth due to overload. It meets the requirements of maintaining efficient and stable cutting performance under high load and high impact conditions, improves its working ability in confined spaces, and can still maintain efficient operation in narrow areas, adapting to the high load-bearing drilling requirements. Attached Figure Description

[0024] Figure 1 This is a three-dimensional view of the overall structure of the polycrystalline diamond composite cutting tooth in Embodiment 1 of this utility model;

[0025] Figure 2 This is a top view of the overall structure of the polycrystalline diamond composite cutting tooth in Embodiment 1 of this utility model;

[0026] Figure 3 This is a perspective view of another overall structure of the polycrystalline diamond composite cutting tooth in Embodiment 1 of this utility model;

[0027] Figure 4 This is a three-dimensional view of the overall structure of the polycrystalline diamond composite cutting tooth in Embodiment 2 of this utility model;

[0028] Figure 5 This is a top view of the overall structure of the polycrystalline diamond composite cutting tooth in Embodiment 2 of this utility model;

[0029] Figure 6 This is a three-dimensional view of the overall structure of the polycrystalline diamond composite cutting tooth in Embodiment 3 of this utility model;

[0030] Figure 7 This is a top view of the overall structure of the polycrystalline diamond composite cutting tooth in Embodiment 3 of this utility model;

[0031] Figure 8 This is a three-dimensional view of the overall structure of the polycrystalline diamond composite cutting tooth in Embodiment 4 of this utility model;

[0032] Figure 9 This is a top view of the overall structure of the polycrystalline diamond composite cutting tooth in Embodiment 4 of this utility model;

[0033] Figure 10 This is a three-dimensional view of the overall structure of the high-efficiency, high-load-bearing drill bit of Embodiment 5 of this utility model;

[0034] Figure 11 This is a perspective view of another overall structure of the high-efficiency, high-load-bearing drill bit of Embodiment 5 of this utility model.

[0035] In the picture:

[0036] 10. Polycrystalline diamond composite cutting teeth;

[0037] 1. Hard alloy substrate; 11. Curved surface; 12. Straight surface; 2. Polycrystalline diamond layer; 21. Working surface; 22. Protrusion; 221. Upper end; 222. Transition surface; 23. Chamfer;

[0038] 20. Drill bit;

[0039] 201. Drill bit body; 202. Connector; 2021. Connecting thread; 203. Cutting tool; 2031. Gauge protection zone; 2032. Crown zone; 2033. Inner cone zone; 2034. Outer cone zone; 204. Columnar gauge protection tooth; 205. Nozzle; 206. Chip removal groove;

[0040] R is the diameter of the circle containing the arc of the cross-section of the curved section; L is the length of the straight side of the cross-section of the straight section. Detailed Implementation

[0041] To facilitate understanding of this utility model, the technical solution and advantages of the utility model will be further described in detail below with reference to the accompanying drawings and embodiments. The specific structure and features of this utility model are illustrated by way of example and should not constitute any limitation on this utility model. Furthermore, any of the technical features mentioned below (including implicit or disclosed features), as well as any technical features directly shown or implied in the figures, can be arbitrarily combined or deleted among these technical features to form other embodiments that may not be directly or indirectly mentioned in this utility model. The accompanying drawings show preferred embodiments of this utility model. However, this utility model can be implemented in many different forms and is not limited to the embodiments described herein.

[0042] In the description of this utility model, unless otherwise stated, all components used are conventional components in the prior art, and can be implemented as long as they meet the beneficial effects of this utility model.

[0043] Example 1

[0044] like Figure 1-3 As shown, this utility model provides a polycrystalline diamond composite cutting tooth 10, comprising a cemented carbide substrate 1 and a polycrystalline diamond layer 2 compositely bonded to the cemented carbide substrate 1. The cemented carbide substrate 1 is composed of two arc-shaped surfaces 11 at both ends and a straight surface 12 between the two arc-shaped surfaces 11, forming a capsule-like cylindrical structure. The end face of the polycrystalline diamond layer 2 away from the alloy substrate is the working surface 21, which is a planar working surface. In this embodiment, the alloy substrate structure is optimized into a capsule-like structure. The reasonable combination of the arc-shaped surfaces 11 and the straight surface 12 ensures uniform distribution of cutting force, improving cutting efficiency and rock-breaking ability. While taking into account cutting force, the transition between the arc-shaped surfaces 11 and the straight surface 12 allows for higher tooth density in space-constrained areas such as the crown region 2032 and the inner cone region 2033 of the drill bit 20, thus optimizing load distribution.

[0045] Preferably, the diameter R of the arc of the cross-section of the curved part 11 is 5-30 mm, and the length of the straight side of the cross-section of the straight part 12 is 1 / 3-5 / 6 of the diameter L of the arc.

[0046] In this embodiment, the diameter R of the arc-shaped section 11 is 5-30mm. This design ensures smoother contact between the arc-shaped section 11 and the formation, and enhances stability during cutting. The arc diameter can also be rationally selected according to different drilling requirements to optimize cutting performance. The straight edge length of the cross-section of the straight section 12 is 1 / 3-5 / 6 of the diameter of the arc-shaped section. By adjusting the ratio of the straight edge length of the straight section 12 to the arc diameter, the load distribution of the drill bit 20 is optimized. A smaller ratio design makes the cutting teeth sharper, enabling more effective penetration into hard rock formations and improving rock-breaking efficiency. As the drill bit penetrates deeper into the formation, the straight section continues cutting, bearing more of the load. A larger ratio design better enhances the durability and stability of the drill bit 20, effectively distributing the load, reducing wear, and maintaining high stability during long-term operation. This is suitable for soft or highly abrasive formations, avoiding excessive wear or reduced cutting efficiency.

[0047] This design ensures a more uniform cutting effect from drill bit 20, reduces performance fluctuations caused by localized wear, and thus improves the stability and operational efficiency of drill bit 20.

[0048] Preferably, the arc lengths of the circles containing the arcs of the two curved surfaces 11 are different, and the same end of the straight edge of the cross-section of the two straight surfaces 12 are close to or far from each other. This forms a fan-shaped design, making the arc lengths of the two curved surfaces 11 different, resulting in different cutting effects of the cutting teeth during drilling, providing smoother and more efficient cutting. For example, when the wider side of the cutting tooth in the fan-shaped structure contacts the formation first, the load distribution of the cutting tooth can be more uniform, avoiding wear or breakage problems caused by excessively concentrated stress in local contact, making the drill bit 20 more stable during drilling.

[0049] In this embodiment, the back rake angle of the polycrystalline diamond composite cutting tooth is in the range of 10-30°. For example, the back rake angle refers to the angle between the working face 21 of the cutting tooth and the drilling direction. Setting this back rake angle range optimizes the cutting force distribution and improves the rock-breaking ability and stability of the drill bit 20.

[0050] This invention utilizes a polycrystalline diamond composite cutting tooth design that optimizes the tooth layout through a straight-edge design. It introduces an innovative "capsule-shaped" composite cutting tooth design, systematically addressing the bottleneck of tooth placement in confined spaces and the failure problem in hard rock conditions for high-load-bearing drill bits 20. The straight-edge design allows for the placement of more cutting teeth in space-constrained areas such as the crown region 2032 and the inner cone region 2033 of the drill bit 20, achieving a higher tooth density. This enables the drill bit 20 to effectively distribute the load within a narrow space, significantly improving the cutting performance in critical areas and enhancing overall drilling efficiency.

[0051] Compared to traditional cylindrical cutting teeth, the optimized cutting tooth structure of this invention can increase the tooth density of drill bit 20 by 20%-50%. The increased density optimizes the load distribution, and the peak load per tooth decreases by 20%-35%, making drill bit 20 more adaptable to harsh drilling conditions with high drilling pressure and high impact, thereby effectively improving rock breaking efficiency and service life of drill bit 20.

[0052] Furthermore, this invention optimizes the geometry of the cutting teeth, effectively improving the uniformity of load distribution through the design of the straight and curved surfaces. The addition of transition surfaces and a well-designed protrusion further enhances the structure, effectively reducing cutting tooth wear caused by overload. The transition surfaces between the protrusions and the curved and straight surfaces effectively alleviate stress concentration during cutting, preventing microscopic cracking and wear of the diamond layer, and extending the service life of the cutting teeth.

[0053] The capsule-shaped cutting tooth structure of this invention is a 180° rotatable symmetrical structure along its central axis. When the diamond layer at the working end wears down to failure, it can be disassembled, rotated 180°, and re-brazed and fixed, using the original non-working end as an effective cutting surface. This achieves secondary utilization of the cutting tooth, significantly reducing the replacement frequency of the cutting tooth, reducing maintenance costs and downtime in drilling operations, and ensuring continuous and efficient operation of the drill bit under complex geological conditions.

[0054] Example 2

[0055] like Figure 4-5 As shown, the difference between this embodiment 2 and embodiment 1 is that the working surface 21 is provided with at least one protrusion 22; the protrusion 22 includes an upper end portion 221 and a transition surface 222 provided between it and the arc-shaped surface portion 11 and / or the straight surface portion 12.

[0056] In further detail, the upper end portion 221 is a planar or convex curved surface structure, and the edge of the upper end portion 221 slopes downward toward the top edge of the straight portion 12 and / or the two ends of the arc portion 11, forming the transition surface 222.

[0057] In this embodiment, the upper end portion 221 is located above the central axis of the working surface 21 of the polycrystalline diamond layer 2 and extends towards the arcuate surface 11 along its central axis. Two transition surfaces 222 are formed between the edge of the upper end portion 221 and the top edges of the two straight surfaces 12, forming a ridge-shaped protrusion. This ridge-shaped protrusion makes the contact surface of the cutting teeth more concentrated. The advantage of this design is that when the drill bit 20 contacts the formation, the protrusion 22 contacts the formation first, enabling it to quickly cut into hard rock layers or solid formations, reducing frictional resistance during cutting, improving the rock-breaking efficiency of the drill bit 20, and adapting to high drilling pressure environments.

[0058] Specifically, the transition surface 222 is a concave curved surface, and a chamfer 23 is provided between the transition surface 222 and the top edge of the arc-shaped surface 11 or the straight surface 12. The concave curved surface makes the contact surface of the drill bit 20 smoother, reducing the impact force between the drill bit 20 and the formation, and also helps to distribute the cutting force more evenly across the entire working face 21 of the drill bit 20, preventing excessive local stress. Furthermore, when the drill bit 20 contacts the rock formation, the chamfer 23 helps to reduce the impact at the contact edge, reducing the risk of cracks appearing in the drill bit 20 during cutting, and also helps to improve cutting stability.

[0059] Example 3

[0060] like Figure 6-7 As shown, the difference between this embodiment 3 and embodiment 2 is that the upper end 221 is located above the arc-shaped surface 11 at one end of the working surface 21 of the polycrystalline diamond layer 2, and is a plane. The edge of the upper end 221 and the top edges of the arc-shaped surface 11 at the other end and the straight surfaces 12 on both sides respectively form three transition surfaces 222.

[0061] In this embodiment, the upper end portion 221 is a square plane and is located above the arc-shaped surface 11 at one end of the working surface 21 of the polycrystalline diamond layer 2. One side edge of the upper end portion 221 coincides with the edge projection of the cemented carbide substrate 1. At the same time, the provision of multiple transition surfaces 222 helps to further distribute the cutting force evenly, enabling the drill bit 20 to adapt to more diverse formation changes and improve the adaptability and overall operating efficiency of the drill bit 20.

[0062] Example 4

[0063] like Figure 8-9 As shown, the difference between this embodiment 4 and embodiments 2 and 3 is that the upper end portion 221 is located above the center of the working surface 21 of the polycrystalline diamond layer 2, and four transition surfaces 222 are formed between the edge of the upper end portion 221 and the top edges of the two end arc surfaces 11 and the two side straight surfaces 12. Furthermore, the transition surfaces 222 are convex curved surfaces.

[0064] In this embodiment, since the upper end 221 is located at the center of the working surface 21, and forms four transition surfaces 222 between it and the top edges of the two end arc surfaces 11 and the two side straight surfaces 12, it forms a rhomboid platform-like protrusion. The four transition surfaces 222 make the pressure distribution more uniform, enhance the stability of the drill bit 20, and improve the penetration power of the drill bit 20.

[0065] Example 5

[0066] like Figure 10-11As shown, this embodiment 5 provides a high-efficiency, high-load-bearing drill bit 20, including a drill bit body 201 and a connector 202. Multiple cutting blades 203 are distributed on the drill bit body 201. Each cutting blade 203 has a gauge protection area 2031, a crown area 2032, an inner cone area 2033, and an outer cone area 2034. Specifically, the drill bit body 201 is an integral structure made of wear-resistant alloy material, capable of withstanding high-load, high-impact drilling environments. The multiple cutting blades 203 are evenly distributed along the outer periphery of the drill bit body 201, ensuring that the working face of the drill bit 20 can perform cutting operations simultaneously, improving drilling efficiency. In this embodiment, the number of cutting blades 203 is 3-12.

[0067] Preferably, the gauge protection zone 2031 is provided with multiple columnar gauge protection teeth 204; their function is to ensure that the drill bit 20 maintains a stable diameter during drilling and avoids deviation. The gauge protection zone 2031 is located on the side of the drill bit 20, and the columnar gauge protection teeth 204 in the gauge protection zone 2031 can be one or more of PDC (polycrystalline diamond), thermally stable polycrystalline (TSP), cemented carbide teeth, inlaid polycrystalline diamond, and impregnated diamond.

[0068] The crown region 2032, inner cone region 2033, and outer cone region 2034 are each provided with a plurality of polycrystalline diamond composite cutting teeth 10 as described in Examples 1-4, spaced apart along the extension direction of the cutting tool 203. The outer cone region 2034 can be configured with the same cutting teeth as the crown region 2032 and inner cone region 2033, or it can be configured with columnar cutting teeth, such as... Figure 11 As shown.

[0069] Further, the drill bit body 201 is also provided with a nozzle 205; the nozzle 205 is used to form a drilling fluid passage; specifically, water holes are respectively provided between adjacent cutting blades, and nozzles 205 are fixedly installed in the water holes; the nozzles 205 communicate with the drilling fluid flow channels in the drill string to form a high-pressure drilling fluid passage. Chip removal grooves 206 are respectively provided between the two cutting blades 203 to guide and remove cuttings and debris generated during drilling. The connector 202 has connecting threads 2021 on its outer periphery. In this embodiment, the connector has API standard threads for direct connection to the drill collar or downhole motor drive shaft.

[0070] The drill bit 20 of this invention achieves a high-density step tooth design through structural optimization of the cutting teeth, which greatly improves the load-bearing capacity and optimizes the load distribution, reducing the risk of damage to individual cutting teeth due to overload. It meets the requirements of maintaining efficient and stable cutting performance under high load and high impact conditions, improves its working ability in confined spaces, and can still maintain efficient operation in narrow areas, adapting to the high load-bearing drilling requirements.

[0071] The above embodiments are merely preferred embodiments of the present utility model and should not be construed as limiting the scope of protection of the present utility model. For those skilled in the art, it will be understood that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present utility model. The scope of the present utility model is defined by the appended claims and their equivalents.

Claims

1. A polycrystalline diamond composite cutting tooth, characterized in that, The invention includes a cemented carbide substrate and a polycrystalline diamond layer bonded to the cemented carbide substrate. The cemented carbide substrate is composed of two arc-shaped surfaces at both ends and a straight surface between the two arc-shaped surfaces to form a capsule-like column structure. The end face of the polycrystalline diamond layer away from the alloy substrate is the working surface. The working surface is either flat or has at least one protrusion. The protrusion includes an upper end and a transition surface between the upper end and the arc-shaped and / or straight surface.

2. The polycrystalline diamond composite cutting tooth as described in claim 1, characterized in that, The diameter of the arc of the cross-section of the curved part is 5-30mm, and the length of the straight side of the cross-section of the straight part is 1 / 3-5 / 6 of the diameter of the arc.

3. The polycrystalline diamond composite cutting tooth as described in claim 2, characterized in that, The arc lengths of the two arc-shaped cross-sections are not the same.

4. The polycrystalline diamond composite cutting tooth as described in claim 2 or 3, characterized in that, The upper end portion has a planar or convex curved surface structure, and the edge of the upper end portion slopes downward toward the top edge of the straight portion and / or the two curved portions at both ends, forming the transition surface.

5. The polycrystalline diamond composite cutting tooth as described in claim 4, characterized in that, The upper end is located above the central axis of the working surface of the polycrystalline diamond layer and extends toward the arc-shaped surface along the central axis direction; the edge of the upper end forms two transition surfaces between the top edges of the two straight surfaces.

6. The polycrystalline diamond composite cutting tooth as described in claim 4, characterized in that, The upper end is located above the arc-shaped surface at one end of the working surface of the polycrystalline diamond layer, and the edge of the upper end forms three transition surfaces between the top edges of the arc-shaped surface and the straight surfaces on both sides at the other end.

7. The polycrystalline diamond composite cutting tooth as described in claim 4, characterized in that, The upper end is located above the center of the working surface of the polycrystalline diamond layer, and four transition surfaces are formed between the edge of the upper end and the top edges of the two curved surfaces and the two straight surfaces.

8. The polycrystalline diamond composite cutting tooth as described in any one of claims 5-7, characterized in that, The transition surface is a concave or convex curved surface, and a chamfer is provided between the top edge of the transition surface and the top edge of the curved or straight surface.

9. A high-efficiency, high-load-bearing drill bit, comprising polycrystalline diamond composite cutting teeth as described in any one of claims 1-8, characterized in that, The drill bit includes a drill bit body and a connector. The drill bit body has multiple cutting blades distributed on it. Each cutting blade has a diameter protection area, a crown area, an inner cone area, and an outer cone area. The diameter protection area has multiple columnar diameter protection teeth. The crown area, the inner cone area, and the outer cone area are each provided with multiple polycrystalline diamond composite cutting teeth at intervals along the extension direction of the cutting blade.

10. The high-efficiency, high-load-bearing drill bit as described in claim 9, characterized in that, The drill bit body is also provided with a nozzle; the nozzle is used to form a drilling fluid passage; chip removal grooves are provided between the two cutting blades; and connecting threads are provided on the outer periphery of the connector.

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