A type of drill bit

Abstract

This application relates to a drill bit comprising: a roller cone, a sealing groove, a first sealing ring, and a second sealing ring. The sealing groove is formed inside the roller cone, with a bearing mud side and a bearing grease side on its two sides, respectively. Both the first and second sealing rings are disposed inside the sealing groove. The first sealing ring seals the bearing grease side, and the second sealing ring seals the bearing mud side. A self-lubricating channel is formed between the first and second sealing rings. In this invention, by using the first and second sealing rings in combination, the amount of extrusion deformation can be automatically adjusted by changes in external pressure, achieving a reliable seal. Simultaneously, the self-lubricating channel formed between the first and second sealing rings allows for self-lubrication using the internal pressure of the bearing, continuously ensuring good lubrication of the sealing area of ​​the sealing ring, improving the service life and reliability of the sealing ring, thereby improving the bearing seal life and reliability.

Description

Technical Field

[0001] This application relates to the field of drill bit bearing seals, and particularly to a drill bit. Background Technology

[0002] The lifespan of a roller cone drill bit is mainly related to the lifespan of its bearings. The bearing seal is a very important component of the bearing, and its main function is to prevent the leakage of grease inside the bearing and to prevent mud from entering the bearing from the outside of the drill bit, thereby ensuring the service life of the drill bit.

[0003] Currently, the seals for roller cone drill bits mainly consist of metal seals and rubber seals. Among the rubber seals, bearing O-rings are generally used. Due to the eccentric rotation of the roller cone under load, the O-ring requires a large amount of extrusion deformation. However, this large extrusion deformation leads to increased sliding frictional heat, and as the bearing wears during use, the bearing clearance increases, significantly reducing the sealing reliability of the O-ring. Based on the problem of O-rings being prone to wear due to large extrusion deformation during use, the O-ring was improved into a flat rubber ring, which improved the sealing stability. However, during use, the flat rubber ring is still susceptible to erosion from sand and other substances carried in the high-pressure mud, causing the rubber on the mud side near the rotating shaft to wear easily after use. Summary of the Invention

[0004] This application provides a drill bit to solve the problem in related technologies where the rubber ring is prone to wear due to increased sliding friction heat and erosion by mud and gravel.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a drill bit comprising: a roller cone, a sealing groove, a first sealing ring, and a second sealing ring, wherein the sealing groove is formed inside the roller cone, and the two sides of the sealing groove are respectively a bearing mud side and a bearing grease side; the first sealing ring and the second sealing ring are both disposed inside the sealing groove, the first sealing ring is used to seal the bearing grease side, the second sealing ring is used to seal the bearing mud side, and a self-lubricating channel is formed between the first sealing ring and the second sealing ring.

[0006] In some embodiments, the sealing groove includes: an inner surface of mud, an inner surface of grease, and a bottom surface of the groove, wherein one side of the inner surface of mud is the bearing mud side; one side of the inner surface of grease is the bearing grease side; and the bottom surface of the groove is located between the inner surface of mud and the inner surface of grease.

[0007] In some embodiments, the bottom surface of the groove is parallel to the surface of the tooth palm journal.

[0008] In some embodiments, the first sealing ring includes: an inner circumferential surface, a first outer surface, and a first inner surface, wherein the inner circumferential surface abuts against the surface of the tooth palm journal; the first outer surface faces the inner surface of the grease; and a self-lubricating channel is formed between the first inner surface and the second sealing ring.

[0009] In some embodiments, the second sealing ring includes: an outer peripheral surface, a second outer side surface, and a second inner side surface, wherein the outer peripheral surface abuts against the bottom surface of the groove; the second outer side surface is opposite to the inner side surface of the mud; and a self-lubricating channel is formed between the second inner side surface and the first inner side surface.

[0010] In some embodiments, the first and second sealing rings both have triangular cross-sections.

[0011] In some embodiments, the distance from the intersection line of the first outer side surface and the first inner side surface to the inner peripheral surface is h1, and the distance from the intersection line of the second outer side surface and the second inner side surface to the outer peripheral surface is h2, satisfying: 1.00≤h2 / h1≤1.13.

[0012] In some embodiments, the angle formed by the first outer surface and the first inner surface is α, and the angle formed by the second outer surface and the second inner surface is β, satisfying: 0.5≤α / β≤1.5.

[0013] In some embodiments, the distance from the bottom surface of the groove to the tooth journal is H, which satisfies: 0.8≤H / h1≤0.9.

[0014] In some embodiments, the hardness of the first and second sealing rings is greater than or equal to 85 Shore A.

[0015] The beneficial effects of the technical solution provided in this application include:

[0016] This application provides a drill bit that uses a first sealing ring and a second sealing ring in combination. The amount of extrusion deformation can be automatically adjusted based on changes in external pressure to achieve a reliable seal. The second sealing ring seals the mud side of the bearing, and the pressure of the mud is transmitted to the first sealing ring through the second sealing ring, thus dynamically changing the amount of extrusion deformation of the first sealing ring. The force on the sealing part of the bearing between the first and second sealing rings is also automatically adjusted with the amount of extrusion deformation, alleviating the continuous sliding friction heat of the rubber at the sealing part. In addition, the second sealing ring assists the first sealing ring in resisting external mud and sand, preventing the intrusion of mud and sand during the extrusion deformation of the first sealing ring. Simultaneously, a self-lubricating channel is formed between the first and second sealing rings, which can achieve self-lubrication using the internal pressure of the bearing, continuously ensuring good lubrication of the sealing area of ​​the sealing ring, improving the service life and reliability of the sealing ring, thereby improving the bearing seal life and reliability. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the overall front cross-sectional structure provided for an embodiment of this application;

[0019] Figure 2 for Figure 1 A magnified view of the structure at point A in the middle;

[0020] Figure 3 This is a schematic diagram of the first sealing ring structure provided in an embodiment of this application;

[0021] Figure 4 This is a schematic diagram of the second sealing ring structure provided in an embodiment of this application;

[0022] Figure 5 This is a schematic diagram of the sealing groove structure provided in an embodiment of this application.

[0023] In the diagram: 1. Toothed palm; 10. Toothed palm journal; 100. Toothed palm journal face; 2. Toothed wheel; 20. Sealing groove; 200. Groove bottom; 201. Inner surface of mud; 202. Inner surface of grease; 203. Self-lubricating channel; 21. Flow channel; 3. Steel ball; 4. Plug pin; 5. Lubricating grease hole; 6. First sealing ring; 60. Inner circumferential surface; 61. First outer surface; 62. First inner surface; 7. Second sealing ring; 70. Outer circumferential surface; 71. Second outer surface; 72. Second inner surface; 73. Inner circumferential part; 8. Bearing mud side; 9. Bearing grease side. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0025] This application provides a drill bit that can solve the problems of increased frictional heat from the sliding friction of the rubber ring and erosion from mud and gravel in related technologies, which can easily lead to wear of the rubber.

[0026] See Figures 1 to 5This application provides a drill bit comprising: a roller cone 2, a sealing groove 20, a first sealing ring 6, and a second sealing ring 7. The sealing groove 20 is formed inside the roller cone 2, with a bearing mud side 8 and a bearing grease side 9 on both sides of the sealing groove 20, respectively. The first sealing ring 6 and the second sealing ring 7 are both disposed inside the sealing groove 20. The first sealing ring 6 is used to seal the bearing grease side 9, and the second sealing ring 7 is used to seal the bearing mud side 8. A self-lubricating channel 203 is formed between the first sealing ring 6 and the second sealing ring 7.

[0027] In this application, by using the first sealing ring 6 and the second sealing ring 7 in combination, the amount of extrusion deformation can be automatically adjusted by changes in external pressure to achieve a reliable seal. The second sealing ring 7 seals the mud side 8 of the bearing, and the pressure of the mud is transmitted to the first sealing ring 6 through the second sealing ring 7, thereby realizing the dynamic change of the amount of extrusion deformation of the first sealing ring 6. The force on the first sealing ring 6 and the second sealing ring 7 and the bearing sealing part is also automatically adjusted with the amount of extrusion deformation, which alleviates the continuous sliding friction heat of the rubber at the sealing part. In addition, the second sealing ring 7 assists the first sealing ring 6 in resisting external mud and sand, preventing the intrusion of mud and sand during the extrusion deformation of the first sealing ring 6. At the same time, a self-lubricating channel 203 is formed between the first sealing ring 6 and the second sealing ring 7, which can achieve self-lubrication by utilizing the internal pressure of the bearing, continuously ensuring good lubrication of the sealing area of ​​the sealing ring, improving the service life and reliability of the sealing ring, thereby improving the bearing sealing life and reliability.

[0028] The roller cone 2 is provided with a bearing hole, and the toothed shaft 1 is provided with a toothed shaft journal 10. The roller cone 2 is connected to the toothed shaft journal 10 through the bearing hole to form a sliding bearing structure. After the steel ball 3 is put into the sliding bearing structure through the plug pin hole, the plug pin 4 is put into the plug pin hole and welded to fix it. The steel ball 3 can keep the roller cone 2 axially on the toothed shaft journal 10. The toothed shaft 1 is provided with a lubricating grease hole 5, which provides lubricating grease to the sliding bearing structure. When the drill bit is working, the internal pressure of the sliding bearing structure fluctuates. The excessive pressure will be adjusted by the oil storage balance system to release the pressure from the oil storage bladder. The sealing groove 20 is formed inside the roller cone 2, that is, at the outer end of the bearing hole of the roller cone 2. The first sealing ring 6 and the second sealing ring 7 are installed in the sealing groove 20. The outer peripheral surface of the roller cone journal 10 is the roller cone journal surface 100. The first sealing ring 6 and the second sealing ring 7 are configured with the roller cone journal surface 100 to form a bearing dynamic seal. The first sealing ring 6 and the second sealing ring 7 separate the external mud medium from the lubricating grease inside the sliding bearing to prevent external mud from entering.

[0029] The first sealing ring 6 and the second sealing ring 7 are used in combination to automatically adjust the amount of extrusion deformation based on changes in external pressure, achieving a reliable seal. The second sealing ring 7 seals the mud side 8 of the bearing, and the pressure of the mud is transmitted to the first sealing ring 6 through the second sealing ring 7, thereby realizing the dynamic change of the amount of extrusion deformation of the first sealing ring 6; the first sealing ring 6 seals the grease side 9 of the bearing, and its sealing extrusion deformation changes with the second sealing ring 7, thereby alleviating the sliding friction heat continuously generated by the rubber at the sealing part.

[0030] Based on the above embodiments, in this embodiment, the sealing groove 20 includes a mud inner surface 201, a grease inner surface 202, and a groove bottom surface 200. One side of the mud inner surface 201 is the bearing mud side 8; one side of the grease inner surface 202 is the bearing grease side 9; the groove bottom surface 200 is located between the mud inner surface 201 and the grease inner surface 202. Specifically, the groove bottom surface 200 is parallel to the surface of the tooth journal 10, and more specifically, the groove bottom surface 200 is parallel to the tooth journal surface 100.

[0031] The first sealing ring 6 includes an inner circumferential surface 60, a first outer surface 61, and a first inner surface 62. The inner circumferential surface 60 abuts against the surface of the tooth palm journal 10. More specifically, abutting means that the inner circumferential surface 60 is in contact with the tooth palm journal surface 100, forming a seal. The first outer surface 61 is opposite to the inner surface 202 of the lubricating grease. A self-lubricating channel 203 is formed between the first inner surface 62 and the second sealing ring 7. "Opposite" means that the connection state between the first outer surface 61 and the inner surface 202 of the lubricating grease is different in different states. In some possible embodiments, the first outer surface 61 and the inner surface 202 of the lubricating grease are in close contact, while in other possible embodiments, there is a gap between the first outer surface 61 and the inner surface 202 of the lubricating grease.

[0032] The second sealing ring 7 includes an outer peripheral surface 70, a second outer surface 71, and a second inner surface 72. The outer peripheral surface 70 abuts against the bottom surface 200 of the tank; the second outer surface 71 faces the inner surface 201 of the mud; and a self-lubricating channel 203 is formed between the second inner surface 72 and the first inner surface 62. More specifically, the outer peripheral surface 70 contacts the bottom surface 200 of the tank to form a seal; "facing" means that the connection state between the second outer surface 71 and the inner surface 201 of the mud is different in different states. In some possible embodiments, the second outer surface 71 is in close contact with the inner surface 201 of the mud, while in other possible embodiments, there is a gap between the second outer surface 71 and the inner surface 201 of the mud.

[0033] Since the tooth palm journal surface 100 forms a seal with the inner circumferential surface 60 of the first sealing ring 6, and the groove bottom surface 200 forms a seal with the outer circumferential surface 70 of the second sealing ring 7, the first sealing ring 6 and the second sealing ring 7 are matched with each other and can be adjusted with the outside world. Therefore, the groove bottom surface 200 is set to be parallel to the surface of the tooth palm journal 10, so that the first sealing ring 6 and the second sealing ring 7 can still form a seal with the inner circumferential surface 60 and the outer circumferential surface 70 when they are adjusted.

[0034] Specifically, the first sealing ring 6 and the second sealing ring 7 are both triangular in cross-section, allowing the compression of the first sealing ring 6 and the second sealing ring 7 to be adjusted in the radial direction, which refers to the direction perpendicular to the tooth journal surface 100. The first sealing ring 6 and the second sealing ring 7 are inserted into the sealing groove 20 with a certain radial compression. The inner circumferential surface 60 of the first sealing ring 6 is configured with the tooth journal surface 100 to form a seal. The first outer surface 61 is opposite to the inner surface 202 of the lubricant. The first inner surface 62 is adjacent to the second inner surface 72 of the second sealing ring 7. A self-lubricating channel 203 is formed between the second inner surface 72 and the first inner surface 62. The outer circumferential surface 70 of the second sealing ring 7 abuts against the bottom surface 200 of the sealing groove 20 to form a seal. The second outer surface 71 is opposite to the inner surface 201 of the mud in the sealing groove 20.

[0035] The intersection of the second outer surface 71 and the second inner surface 72 on the second sealing ring 7 is the inner circumference 73. After the second sealing ring 7 is compressed, the inner circumference 73 is configured with the toothed shaft neck surface 100 to form an auxiliary seal. The sealing contact area between the inner circumference 73 and the toothed shaft neck surface 100 is small, so the heat generated by sliding friction is small. The inner circumference 73 can also prevent external mud from entering and protect the seal formed by the contact between the inner circumference surface 60 and the toothed shaft neck surface 100.

[0036] When the pressure on the external bearing mud side 8 is high, the mud fluid pressure acts on the second outer surface 71 of the second sealing ring 7. After the second sealing ring 7 is subjected to force, the second inner surface 72 of the second sealing ring 7 comes into contact with the first inner surface 62 of the first sealing ring 6 and pushes the force inward to the first sealing ring 6. The inner circumferential surface 60 of the first sealing ring 6 further presses the toothed shaft neck surface 100, thereby forming a larger sealing force and improving the sealing reliability when the external mud pressure increases. When the pressure on the external bearing mud side 8 decreases, the pressure on the second outer surface 71 of the second sealing ring 7 decreases, and the first sealing ring 6 attempts to return to its original position. As a result, the amount of compression between the inner circumferential surface 60 of the first sealing ring 6 and the toothed shaft neck surface 100 decreases, and the sealing force between the inner circumferential surface 60 and the toothed shaft neck surface 100 decreases. At this time, the frictional heat generated between the inner circumferential surface 60 of the first sealing ring 6 and the toothed shaft neck surface 100 decreases. During this process, as the pressure on the bearing mud side 8 decreases, the grease on the bearing grease side 9 is simultaneously pumped through the flow channel 21 between the first outer surface 61 and the inner surface 202 of the sealing groove 20, providing lubrication to the sealing surface. Similarly, when the bearing experiences a sudden increase in internal grease pressure due to excessive pressure, and the pressure of the grease inside the bearing, i.e., in the flow channel 21, increases, the pressure that cannot be released through the oil reservoir bladder by the oil balance system will act on the first outer surface 61 of the first sealing ring 6. After the first sealing ring 6 is subjected to force, the first inner surface 62 and the second inner surface 72 of the second sealing ring 7 come into contact with each other and transmit the force to the second sealing ring 7. The radial compression between the inner circumference 73 of the second sealing ring 7 and the toothed journal 10 increases, that is, the radial compression between the inner circumference 73 and the toothed journal surface 100 increases, thus increasing the ability to resist external mud. At the same time, the radial extrusion between the inner circumferential surface 60 of the first sealing ring 6 and the toothed journal 10 decreases, that is, the radial extrusion between the inner circumferential surface 60 and the toothed journal surface 100 decreases and the sealing force decreases. At this time, the frictional heat generated between the inner circumferential surface 60 of the first sealing ring 6 and the toothed journal surface 100 decreases. Meanwhile, grease is squeezed into the space between the first outer surface 61 of the first sealing ring 6 and the inner surface 202 of the grease in the sealing groove 20, providing lubrication to the bearing sealing surface.

[0037] Based on the above embodiments, in this embodiment, it has been found that the dimensions of the first sealing ring 6 and the second sealing ring 7, the dimensional relationship between them and the sealing groove 20, and the hardness have a significant impact on the lifespan and sealing reliability of the first sealing ring 6 and the second sealing ring 7.

[0038] The distance from the intersection of the first outer surface 61 and the first inner surface 62 to the inner circumferential surface 60 is h1, and the distance from the intersection of the second outer surface 71 and the second inner surface 72 to the outer circumferential surface 70 is h2, satisfying: 1.00≤h2 / h1≤1.13; the included angle formed by the first outer surface 61 and the first inner surface 62 is α, and the included angle formed by the second outer surface 71 and the second inner surface 72 is β, satisfying: 0.5≤α / β≤1.5; the distance from the groove bottom surface 200 to the tooth palm journal 10 is H, more specifically, the distance from the groove bottom surface 200 to the tooth palm journal surface 100 is H, satisfying: 0.8≤H / h1≤0.9; the first sealing ring 6 and the second sealing ring 7 are made of nitrile rubber, hydrogenated nitrile rubber or other wear-resistant synthetic elastomers, with a hardness greater than or equal to 85 Shore A.

[0039] The invention can be better understood by referring to the following embodiments, which are included herein to describe exemplary implementations only and should not be construed as covering the full scope of the invention:

[0040] Based on the conditions that 1.00≤h2 / h1≤1.13, 0.5≤α / β≤1.5, 0.8≤H / h1≤0.9, and the hardness of the first sealing ring 6 and the second sealing ring 7 is greater than or equal to 85 Shore A, the angle α between the first outer surface 61 and the first inner surface 62 of the first sealing ring 6 is set to 80°, the distance h1 from the intersection line of the first outer surface 61 and the first inner surface 62 to its inner circumferential surface 60 is 6.5 mm, the angle β between the second outer surface 71 and the second inner surface 72 of the second sealing ring 7 is 60°, the distance h2 from the intersection line of the second outer surface 71 and the second inner surface 72 to the outer circumferential surface 70 is 7.2 mm, the distance H from the groove bottom surface 200 to the tooth palm journal surface 100 is 5.8 mm, and the hardness of the first sealing ring 6 and the second sealing ring 7 is 87 Shore A. The first sealing ring 6 and the second sealing ring 7 were installed in a sealing testing machine for sealing test evaluation. The outer side of the second outer surface 71 of the second sealing ring 7 was sealed with mud, and the outer side of the first outer surface 61 of the first sealing ring 6 was sealed with grease. The mud sealed by the second outer surface 71 of the second sealing ring 7 was cyclically pressurized at a certain frequency of 0 to 2.0 MPa. After the first sealing ring 6 and the second sealing ring 7 worked continuously at a speed of 450 rpm for 2.16 million revolutions, the seal was effective. The appearance of the two sealing rings was good, with basically no wear marks.

[0041] To better demonstrate the benefits of satisfying 1.00≤h2 / h1≤1.13, 0.5≤α / β≤1.5, 0.8≤H / h1≤0.9, and the hardness of the first sealing ring 6 and the second sealing ring 7 being greater than or equal to 85 Shore A, the following comparative example is implemented;

[0042] Comparative Example 1: The angle α between the first outer surface 61 and the first inner surface 62 of the first sealing ring 6 is 80°, the distance h1 from the intersection line of the first outer surface 61 and the first inner surface 62 to its inner circumferential surface 60 is 6.5 mm, the angle β between the second outer surface 71 and the second inner surface 72 of the second sealing ring 7 is 60°, the distance h2 from the intersection line of the second outer surface 71 and the second inner surface 72 to the outer circumferential surface 70 is 6.42 mm, i.e., h2 / h1=0.988, the distance H from the groove bottom surface 200 to the tooth palm journal surface 100 is 5.8 mm, and the hardness of the first sealing ring 6 and the second sealing ring 7 is 87 Shore A. The first sealing ring 6 and the second sealing ring 7 are installed in a sealing testing machine for sealing test evaluation. The outer side of the second outer surface 71 of the second sealing ring 7 is sealed with mud, and the outer side of the first outer surface 61 of the first sealing ring 6 is sealed with grease. The mud sealed by the second outer surface 71 of the second sealing ring 7 is cyclically pressurized at a certain frequency of 0-2.0 MPa. After the first sealing ring 6 and the second sealing ring 7 work continuously at a speed of 450 rpm for 2.16 million revolutions, the seal is effective. Mud enters between the second inner surface 72 of the second sealing ring 7 and the first inner surface 62 of the first sealing ring 6. The rubber at the contact part between the first inner surface 62 of the first sealing ring 6 and the toothed shaft journal surface 100 has a certain degree of wear.

[0043] Comparative Example 2: The angle α between the first outer surface 61 and the first inner surface 62 of the first sealing ring 6 is 80°, the distance h1 from the intersection line of the first outer surface 61 and the first inner surface 62 to its inner circumferential surface 60 is 6.5 mm, the angle β between the second outer surface 71 and the second inner surface 72 of the second sealing ring 7 is 60°, the distance h2 from the intersection line of the second outer surface 71 and the second inner surface 72 to the outer circumferential surface 70 is 7.2 mm, the distance H from the groove bottom surface 200 to the tooth palm cervical surface 100 is 6.4 mm, that is, H / h1=0.985, and the hardness of the first sealing ring 6 and the second sealing ring 7 is 87 Shore A. The first sealing ring 6 and the second sealing ring 7 are installed in a sealing testing machine for sealing test evaluation. The outer side of the second outer surface 71 of the second sealing ring 7 is sealed with mud, and the outer side of the first outer surface 61 of the first sealing ring 6 is sealed with grease. The mud sealed by the second outer surface 71 of the second sealing ring 7 is cyclically pressurized at a certain frequency of 0 to 2.0 MPa. After the first sealing ring 6 and the second sealing ring 7 work continuously at a speed of 450 rpm for 800,000 revolutions, the seal fails.

[0044] Comparative Example 3: The angle α between the first outer surface 61 and the first inner surface 62 of the first sealing ring 6 is 80°, the distance h1 from the intersection line of the first outer surface 61 and the first inner surface 62 to its inner circumferential surface 60 is 6.5 mm, the angle β between the second outer surface 71 and the second inner surface 72 of the second sealing ring 7 is 60°, the distance h2 from the intersection line of the second outer surface 71 and the second inner surface 72 to the outer circumferential surface 70 is 7.2 mm, the distance H from the groove bottom surface 200 to the tooth palm journal surface 100 is 5.8 mm, and the hardness of the first sealing ring 6 and the second sealing ring 7 is 75 Shore A. The first sealing ring 6 and the second sealing ring 7 were installed in a sealing testing machine for sealing test evaluation. The outer side of the second outer surface 71 of the second sealing ring 7 was sealed with mud, and the outer side of the first outer surface 61 of the first sealing ring 6 was sealed with grease. The mud sealed by the second outer surface 71 of the second sealing ring 7 was cyclically pressurized at a certain frequency of 0 to 2.0 MPa. After the first sealing ring 6 and the second sealing ring 7 worked continuously at a speed of 450 rpm for 2.16 million revolutions, the seal was effective. The inner circumference 73 of the second sealing ring 7 was bent and deformed, and mud entered the self-lubricating channel 203. The rubber at the contact point between the first inner surface 62 of the first sealing ring 6 and the toothed shaft journal surface 100 was severely worn.

[0045] Comparative Example 4: The angle α between the first outer surface 61 and the first inner surface 62 of the first sealing ring 6 is 30°, the distance h1 from the intersection line of the first outer surface 61 and the first inner surface 62 to its inner circumferential surface 60 is 6.5 mm, the angle β between the second outer surface 71 and the second inner surface 72 of the second sealing ring 7 is 80°, i.e., α / β = 0.375, the distance h2 from the intersection line of the second outer surface 71 and the second inner surface 72 to the outer circumferential surface 70 is 7.2 mm, the distance H from the groove bottom surface 200 to the tooth palm journal surface 100 is 5.8 mm, and the hardness of the first sealing ring 6 and the second sealing ring 7 is 87 Shore A. The first sealing ring 6 and the second sealing ring 7 were installed in a sealing testing machine for sealing test evaluation. The outer side of the second outer surface 71 of the second sealing ring 7 was sealed with mud, and the outer side of the first outer surface 61 of the first sealing ring 6 was sealed with grease. The mud sealed by the second outer surface 71 of the second sealing ring 7 was cyclically pressurized at a certain frequency of 0 to 2.0 MPa. After the first sealing ring 6 and the second sealing ring 7 worked continuously at a speed of 450 rpm for 2.16 million revolutions, the seal was effective. The appearance of the first sealing ring 6 and the second sealing ring 7 was basically good, but circumferential wear marks appeared on the inner circumferential surface 60 of the first sealing ring 6.

[0046] In the description of this application, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0047] It should be noted that in this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0048] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A drill bit, characterized in that, It includes: Toothed wheel (2); A sealing groove (20) is formed inside the toothed wheel (2), and the two sides of the sealing groove (20) are the bearing mud side (8) and the bearing grease side (9), respectively. A first sealing ring (6) and a second sealing ring (7) are both disposed inside the sealing groove (20). The first sealing ring (6) is used to seal the bearing grease side (9), and the second sealing ring (7) is used to seal the bearing mud side (8). A self-lubricating channel (203) is formed between the first sealing ring (6) and the second sealing ring (7). The sealing groove (20) includes: The inner surface of the mud (201) is a bearing mud side (8). The inner surface of the grease (202) is one side of the bearing grease side (9); The bottom surface (200) of the tank is located between the inner surface of the mud (201) and the inner surface of the grease (202); The first sealing ring (6) includes: The inner circumferential surface (60) abuts against the surface of the tooth palm neck (10); The first outer surface (61) is opposite to the inner surface (202) of the grease; A self-lubricating channel (203) is formed between the first inner surface (62) and the second sealing ring (7). The second sealing ring (7) includes: The outer peripheral surface (70) abuts against the bottom surface (200) of the groove; The second outer surface (71) is opposite to the inner surface (201) of the mud; A self-lubricating channel (203) is formed between the second inner surface (72) and the first inner surface (62). The distance from the intersection line of the first outer side surface (61) and the first inner side surface (62) to the inner peripheral surface (60) is h1, and the distance from the intersection line of the second outer side surface (71) and the second inner side surface (72) to the outer peripheral surface (70) is h2, satisfying: 1.00≤h2 / h1≤1.

13.

2. The drill bit as described in claim 1, characterized in that: The bottom surface (200) of the groove is parallel to the surface of the tooth palm neck (10).

3. The drill bit as described in claim 1, characterized in that: The first sealing ring (6) and the second sealing ring (7) both have triangular cross sections.

4. The drill bit as described in claim 1, characterized in that: The angle formed by the first outer surface (61) and the first inner surface (62) is α, and the angle formed by the second outer surface (71) and the second inner surface (72) is β, satisfying: 0.5≤α / β≤1.

5.

5. The drill bit as described in claim 1, characterized in that: The distance from the bottom surface (200) of the groove to the tooth palm journal (10) is H, which satisfies: 0.8≤H / h1≤0.

9.

6. The drill bit as described in claim 1, characterized in that: The first sealing ring (6) and the second sealing ring (7) have a hardness greater than or equal to 85 Shore A.

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