A rotary drill bit with a wear-resistant bushing

Abstract

This utility model relates to the field of rotary drilling rig drill bit technology, and discloses a rotary drilling rig drill bit with a wear-resistant bushing. It includes a connector, a connecting flange, a drill barrel, a connecting base, and the drill bit. The connecting flange is located at the bottom of the connector, the drill barrel is located at the bottom of the connecting flange, and the connecting base is located at the bottom of the drill barrel. The drill bit is installed in a ring-shaped arrangement at the bottom of the connecting base. A wear-resistant bushing is detachably installed on the outer side of the drill barrel and is fixed to the outer wall of the drill barrel by a radial locking mechanism. By designing the wear-resistant bushing as a segmented, detachable structure, "on-demand maintenance" is achieved. When a part of the bushing (such as the bottom where wear is fastest) fails, only that module can be replaced, without scrapping the entire drill bit or the most valuable drill barrel base. This significantly reduces spare parts costs and inventory pressure, and minimizes equipment downtime.

Description

Technical Field

[0001] This utility model relates to the field of rotary drilling rig drill bit technology, and in particular to a rotary drilling rig drill bit with a wear-resistant bushing. Background Technology

[0002] Rotary drilling rigs, as a highly efficient foundation pile hole-forming device, are widely used in foundation construction for buildings, bridges, and other projects. When applied to hard rock formations, conventional drill buckets are inefficient or even unable to drill through. In such cases, specially designed barrel drills (or circumferential drill bits) are required. These barrel drills use cutting teeth arranged at the bottom of the drill barrel to break up and form holes in the hard rock in a circumferential manner.

[0003] Patent document CN219101221U discloses a barrel drill for a hard rock ring-cutting rotary drilling rig, comprising a barrel body, a connecting block fixedly connected to the upper part of the barrel body, and a reinforcing barrel section welded to the lower part. The bottom plane of the reinforcing barrel section is provided with plate-shaped drill teeth arranged in a ring at intervals. Alloy beads are arranged on three sides of the drill teeth to achieve simultaneous cutting with the contact surface of the rock, making drilling easier. The thinness of the drill teeth reduces drilling resistance and makes it easier to form a ring-shaped cutting surface. The optimized slag removal setting facilitates slag removal and avoids repeated crushing. The tooth mounting base is welded to the reinforcing ring of the barrel body, resulting in stronger connection and avoiding deformation and other failures.

[0004] However, in practical engineering applications, hard rock formations are highly abrasive, resulting in direct and intense friction between the drill bit casing and the borehole wall and rock. Furthermore, the casing is often a single steel plate structure, which, despite its thickness, wears out extremely quickly on its outer side during high-intensity hard rock drilling. This significantly shortens the drill bit's lifespan, increasing construction costs and replacement frequency. Therefore, we provide a rotary drilling rig bit with a wear-resistant bushing to address this issue. Utility Model Content

[0005] To overcome the above shortcomings, this utility model provides a rotary drilling rig bit with a wear-resistant bushing, which aims to improve the problem of excessive wear and short service life of the outer shell of the existing medium-bore drill bit when drilling in hard rock formations due to direct friction.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: a rotary drilling rig drill bit with a wear-resistant bushing, comprising a connector, a connecting flange, a drill barrel, a connecting base, and a drill bit. The connector has a connecting flange at its bottom, a drill barrel at its bottom, a connecting base at its bottom, and drill bits arranged in a ring at the bottom of the connecting base. A wear-resistant bushing is detachably installed on the outer side of the drill barrel, and the wear-resistant bushing is fixed to the outer wall of the drill barrel by a radial locking mechanism.

[0007] As a further description of the above technical solution:

[0008] The wear-resistant bushing is composed of multiple bushing rings spliced ​​along the drill barrel axis, including a first bushing at the top, at least one second bushing in the middle, and a third bushing at the bottom.

[0009] As a further description of the above technical solution:

[0010] The adjacent bushing rings are connected by a plug-in structure, which includes a plug-in plate disposed at one end of one bushing ring and a plug-in groove disposed at the corresponding end of another bushing ring. The mating surfaces of the plug-in plate and the plug-in groove form a labyrinthine concave-convex structure.

[0011] As a further description of the above technical solution:

[0012] On the inner side of the plug-in structure, that is, on the side of the plug-in plate and the plug-in groove near the center of the drill barrel, a sealing structure is provided. The sealing structure includes an O-ring sealing groove opened on the end face of the bushing ring and an O-ring sealing ring embedded in the groove.

[0013] As a further description of the above technical solution:

[0014] The radial locking mechanism includes: a locking block base welded to a blind hole in the outer wall of the drill barrel; the locking block base has a threaded hole; each bushing ring of the wear-resistant bushing has a through hole corresponding to the position of the locking block base; and a locking fastener is provided in the through hole; the locking fastener passes through the through hole on the bushing ring in sequence and is screwed into the threaded hole of the locking block base, thereby pressing and fixing the wear-resistant bushing to the drill barrel.

[0015] As a further description of the above technical solution:

[0016] The through path of the locking fastener and the location of the O-ring are spatially offset.

[0017] As a further description of the above technical solution:

[0018] The top of the first bushing is provided with a mounting plate that mates with the connecting flange, and the mounting plate and the connecting flange are fixedly connected by fasteners. The top of the connecting base is provided with an annular positioning boss, and the bottom of the third bushing is provided with a positioning groove. The connecting base is embedded in the positioning groove at the bottom of the third bushing through the positioning boss, thereby achieving preliminary axial and radial positioning.

[0019] As a further description of the above technical solution:

[0020] The wear-resistant bushing has a countersunk hole at the inlet of the through hole, and a sealing ring groove is opened at the bottom of the countersunk hole. A sealing ring is provided thereon. When the head of the locking fastener is tightened, it presses against the sealing ring to form a radial seal.

[0021] As a further description of the above technical solution:

[0022] The base material of the drill barrel is high-strength structural steel, and the material of the wear-resistant bushing is high-manganese steel, alloy wear-resistant steel or metal matrix composite material. The working surface of the wear-resistant bushing is welded with a wear-resistant hard alloy layer or has a wear-reducing coating.

[0023] In summary, due to the adoption of the above technical solution, the beneficial effects of this application are as follows:

[0024] 1. In this utility model, by designing the wear-resistant bushing as a segmented, detachable structure, "on-demand maintenance" is achieved. When a part of the bushing (such as the bottom where wear is fastest) fails, only that part of the module can be replaced, without scrapping the entire drill bit or the most valuable drill barrel base. This greatly reduces spare parts costs and inventory pressure, and minimizes equipment downtime.

[0025] 2. In this utility model, a passive-active composite seal is formed by adopting a "labyrinth structure + O-ring" at the bushing ring interface. Furthermore, countersunk holes and sealing rings are provided at each installation point of the locking fastener, forming a reliable secondary seal. This effectively prevents corrosion of the drill barrel base and the locking mechanism, ensuring long-term connection reliability and the service life of the drill barrel. Attached Figure Description

[0026] Figure 1 This utility model presents a perspective view of the connection structure between the first bushing, the second bushing, the third bushing, and the drill bit of a rotary drilling rig with wear-resistant bushings.

[0027] Figure 2 A perspective view of the drill barrel structure of a rotary drilling rig drill bit with a wear-resistant bushing proposed in this utility model;

[0028] Figure 3 A three-dimensional cross-sectional view of the wear-resistant bushing connection of a rotary drilling rig bit with a wear-resistant bushing, as proposed in this utility model.

[0029] Figure 4 This invention provides a cross-sectional view of the connection structure between the wear-resistant bushing and the drill barrel of a rotary drilling rig bit with a wear-resistant bushing.

[0030] Legend:

[0031] 1. Connector; 2. Connecting flange; 3. Drill barrel; 4. Connecting base; 5. Drill bit; 6. Wear-resistant bushing; 61. First bushing; 62. Second bushing; 63. Third bushing; 7. Insert plate; 8. Insert groove; 9. O-ring sealing groove; 10. O-ring seal; 11. Locking block base; 12. Locking fastener; 13. Mounting plate. Detailed Implementation

[0032] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0033] Reference Figures 1-4 This utility model provides an embodiment of a rotary drilling rig drill bit with a wear-resistant bushing. Its core functional components, arranged axially from top to bottom, are: a connector 1, a connecting flange 2, a wear-resistant bushing system, a drill barrel 3, a connecting base 4, and a drill bit 5. The connector 1, located at the very top of the drill bit, is a standard interface used for rigid connection with the drill rod of the rotary drilling rig, transmitting torque and pressure. The connecting flange 2 is a thick annular steel plate with multiple bolt holes evenly distributed on it. Its upper end is welded to the connector 1, and its lower end is welded to the drill barrel 3. It is a key structure for power transmission. The drill barrel 3 is the core base, a cylindrical structure. The connecting base 4 is welded to the bottom of the drill barrel 3, and its lower part has a mounting seat for mounting the drill bit 5. The drill bit 5 consists of multiple cutting teeth or roller cones, responsible for cutting and breaking up rock and soil. The wear-resistant bushing 6 is fitted on the outside of the drill barrel 3 and is made of high manganese steel (ZGMn13) or Hardox series alloy wear-resistant steel. Its overall hardness is much higher than that of the drill barrel 3 matrix.

[0034] In this embodiment, the bushing is divided into three sections along the axial direction: a first bushing 61, a second bushing 62, and a third bushing 63. The top of the first bushing 61 is integrally cast or machined into an annular mounting plate 13. This mounting plate 13 has multiple evenly distributed holes. During installation, the first bushing 61 is fitted onto the drill barrel 3, ensuring that its mounting plate 13 is tightly fitted against the lower end face of the connecting flange 2. High-strength bolts are passed through the holes in the mounting plate 13 and screwed into the pre-drilled threaded holes on the corresponding positions of the lower end face of the connecting flange 2, thereby firmly fixing the top of the first bushing 61 to the top of the drill barrel 3. An annular positioning boss with a height of approximately 20-30mm is machined into the top of the connecting base 4. The outer diameter of this boss is precision machined. Correspondingly, a positioning groove with a depth matching the height of the positioning boss is machined into the bottom of the third bushing 63. The third bushing 63 is fitted into the drill barrel 3 from bottom to top, ensuring that the positioning groove at its bottom precisely fits into the positioning boss of the connecting base 4. This structure enables the initial positioning of the third bushing 63 in the radial and circumferential directions, effectively restricting its horizontal movement and rotation.

[0035] Taking the connection between the second bushing 62 and the third bushing 63 as an example. On the bottom end face of the second bushing 62, there is an annular insertion plate 7 with a "convex" shaped cross-section. On the top end face of the third bushing 63, there is a precisely complementary insertion groove 8 with a "concave" shaped cross-section. The entire mating surface of the insertion plate 7 and the insertion groove 8 is designed with a stepped concave-convex structure of three or more layers, i.e., a labyrinth seal. This structure, independent of contact pressure, can greatly extend the fluid permeation path, dissipate its kinetic energy, and effectively block abrasive particles.

[0036] On the innermost side of the end face where the insertion groove 8 is located (i.e., the side closest to the central axis of the drill barrel 3), an O-ring sealing groove 9 is formed. An oil-resistant and mud-resistant hydrogenated nitrile rubber O-ring 10 is placed in this groove. When the insertion plate 7 is inserted into the insertion groove 8 and compressed by the locking mechanism, the labyrinth structure first comes into play, and the O-ring 10 is compressed to 15%-20% of its cross-sectional diameter, generating a huge rebound force, forming an absolutely reliable elastic sealing barrier between the metal interfaces.

[0037] like Figures 3-4 As shown, the radial locking mechanism is crucial for ensuring a tight fit between each bushing ring and the drill barrel 3. Multiple blind holes that do not penetrate the barrel wall are machined on the outer wall of the drill barrel 3. Pre-machined locking block bases 11 are welded securely into these blind holes. An internally threaded hole is machined at the center of the locking block base 11. Through holes are drilled on the first, second, and third bushing rings at positions corresponding to the locking block base 11. A countersunk hole is machined at the entrance of each through hole, and a standard O-ring sealing groove is machined at the bottom of the countersunk hole, into which a smaller O-ring is embedded as a sealing ring 14. The locking fastener 12 is a hexagonal head screw.

[0038] In this embodiment, after the bushing ring is fitted onto the drill barrel and aligned, the locking fastener 12 is inserted from the outside of the bushing ring, with its head pressing against the sealing ring 14. The shank passes through the through hole of the bushing ring and is finally screwed into the threaded hole of the locking block base 11. A torque wrench is used to tighten it to a preset torque. During this process, the tension of the screw firmly fixes the bushing ring to the drill barrel. The screw head presses against the sealing ring 14, achieving a radial seal on the screw mounting hole itself, preventing media from entering. The screw's path is completely separated and offset from the O-ring seal 10 at the bushing ring interface in space; the two complement each other functionally and do not interfere with each other, together forming a three-dimensional, seamless sealing network. To further improve performance, a 3-5mm thick layer of tungsten carbide-based wear-resistant hard alloy is deposited on the outer working surface of the wear-resistant bushing 6 (i.e., the surface directly in contact with the hole wall) using carbon arc welding or plasma spraying. This greatly improves the wear life of the bushing.

[0039] The implementation principle of this embodiment of a rotary drilling rig drill bit with a wear-resistant bushing is as follows: During use, the connecting flange 2 is rigidly connected to the drill rod of the rotary drilling rig through a standard interface to transmit torque and pressure. During drilling in hard rock formations, the cutting teeth at the bottom of the drill bit 5 break the rock in a ring-cutting manner, while the wear-resistant bushing 6 directly contacts the borehole wall. Because the wear-resistant bushing 6 is made of wear-resistant materials such as high-manganese steel, and a wear-resistant hard alloy layer is welded onto its working surface or a friction-reducing coating is applied, its wear resistance is much higher than that of the drill barrel 3 substrate, effectively preventing direct friction and erosion of the drill barrel 3 by the borehole wall. When vibration or torque occurs during drilling, the segmented wear-resistant bushing 6 is tightly fixed to the drill barrel 3 via a radial locking mechanism. The mounting plate 13 at the top of the first bushing 61 is bolted to the connecting flange 2. The positioning groove at the bottom of the third bushing 63 engages with the positioning boss of the connecting base 4. Combined with the labyrinthine insertion structure between each bushing ring and the O-ring seal, the stability and sealing of the overall structure are ensured, preventing mud and rock cuttings from entering the gap between the drill barrel 3 and the wear-resistant bushing 6, thus avoiding corrosion of the drill barrel 3 base and failure of the locking mechanism. After long-term use, if the third bushing 63 at the bottom reaches the replacement threshold due to wear, the bolts between the connecting flange 2 and the mounting plate 13 of the first bushing 61 can be removed first. Then, the locking fasteners 12 of each radial locking mechanism can be unscrewed, and the first bushing 61 and the second bushing 62 can be removed in sequence. Finally, the worn third bushing 63 can be removed from the positioning boss of the connecting base 4, and a new third bushing 63 can be replaced. After that, the parts can be reassembled in the reverse order to achieve partial maintenance and replacement, reducing operating costs.

[0040] Finally, it should be noted that the above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Although the present utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A rotary excavator drill bit with a wear-resistant bushing, comprising a connecting head (1), a connecting flange (2), a drill cylinder (3), a connecting base (4) and a drill bit (5), characterized in that, The bottom of the connector (1) is provided with a connecting flange (2), the bottom of the connecting flange (2) is provided with a drill barrel (3), the bottom of the drill barrel (3) is provided with a connecting base (4), the bottom of the connecting base (4) is provided with drill bits (5) arranged in a ring, and a wear-resistant bushing (6) is detachably installed on the outside of the drill barrel (3). The wear-resistant bushing (6) is fixed to the outer wall of the drill barrel (3) by a radial locking mechanism.

2. The rotary excavating tool drill bit with a wear-resistant bushing of claim 1, wherein: The wear-resistant bushing (6) is formed by splicing multiple bushing rings along the axial direction of the drill barrel (3), including a first bushing (61) at the top, at least one second bushing (62) in the middle, and a third bushing (63) at the bottom.

3. The rotary excavating tool drill bit with wear resistant bushings of claim 2, wherein: The adjacent bushing rings are connected by a plug-in structure, which includes a plug-in plate (7) disposed at one end of a bushing ring and a plug-in groove (8) disposed at the corresponding end of another bushing ring. The mating surfaces of the plug-in plate (7) and the plug-in groove (8) form a labyrinthine concave-convex structure.

4. The rotary excavating tool drill bit with wear resistant bushings of claim 3, wherein: On the inner side of the plug-in structure, that is, on the side of the plug-in plate (7) and the plug-in groove (8) near the center of the drill barrel (3), a sealing structure is provided. The sealing structure includes an O-ring sealing groove (9) opened on the end face of the bushing ring and an O-ring sealing ring (10) embedded in the groove.

5. The rotary excavating tool drill bit with wear resistant bushings of claim 4, wherein: The radial locking mechanism includes: a locking block base (11) welded into a blind hole on the outer wall of the drill barrel (3), the locking block base (11) having a threaded hole, and each bushing ring of the wear-resistant bushing (6) having a through hole corresponding to the position of the locking block base (11), and a locking fastener (12) being provided in the through hole. The locking fastener (12) passes through the through hole on the bushing ring in sequence and is screwed into the threaded hole of the locking block base (11) to press and fix the wear-resistant bushing (6) onto the drill barrel (3).

6. The rotary excavating tool drill bit with a wear-resistant bushing of claim 5, wherein: The through path of the locking fastener (12) is spatially offset from the position of the O-ring seal (10).

7. The rotary excavating tool bit with wear sleeve of claim 2, wherein: The top of the first bushing (61) is provided with a mounting plate (13) that mates with the connecting flange (2), and the mounting plate (13) and the connecting flange (2) are fixedly connected by fasteners. The top of the connecting base (4) is provided with an annular positioning boss, and the bottom of the third bushing (63) is provided with a positioning groove. The connecting base (4) is embedded in the positioning groove at the bottom of the third bushing (63) through the positioning boss, thereby achieving preliminary axial and radial positioning.

8. The rotary excavating tool bit with wear sleeve of claim 6, wherein: The wear-resistant bushing (6) has a countersunk hole at the inlet of the through hole. A sealing ring groove is opened at the bottom of the countersunk hole and a sealing ring is provided. When the head of the locking fastener (12) is tightened, it presses the sealing ring to form a radial seal.

9. The rotary excavating tool bit with wear sleeve of claim 1, wherein: The base material of the drill barrel (3) is high-strength structural steel, and the material of the wear-resistant bushing (6) is high-manganese steel, alloy wear-resistant steel or metal-based composite material. The working surface of the wear-resistant bushing (6) is welded with a wear-resistant hard alloy layer or has a wear-reducing coating.

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