High temperature resistant drill bit

Abstract

The application relates to a high-temperature-resistant drill bit, which comprises a blade shaft neck and a roller rotatably connected to the blade shaft neck, the root of the blade shaft neck is provided with a sealing groove, a sealing assembly is arranged between the blade shaft neck and the roller, and the sealing assembly comprises: an insert sleeve which is inlaid into the inner cavity of the shaft hole of the roller; a rigid ring which is movably connected to the end face of the insert sleeve; an elastic sealing gasket which is arranged in the sealing groove and seals the rigid ring and the blade shaft neck along the axial direction of the blade shaft neck, the contact surface of the elastic sealing gasket and the groove bottom of the sealing groove is a concave curved surface, and the radial width of the elastic sealing gasket along the blade shaft neck is smaller than the width of the groove bottom of the sealing groove; and an elastic energy-supply ring which is arranged between the inner wall of the rigid ring close to the blade shaft neck and the blade shaft neck. The sealing can adapt to a high temperature of 300 DEG C, and the problem that the elastic sealing gasket is easily broken after a large volume expansion under the linear thermal expansion characteristics of perfluoroether rubber at high temperature, and the sealing is invalid after mud enters the bearing is solved.

Description

Technical Field

[0001] This application relates to the field of drill bit bearing sealing technology, and in particular to a high-temperature resistant drill bit. Background Technology

[0002] The development of deep and ultra-deep oil and gas, as well as unconventional energy drilling operations, is showing a year-on-year increasing trend in China. The development of deep oil and gas in Northwest China, tight oil and gas and shale oil and gas in Southwest China, and hot dry rock resources in Qinghai and other areas will become the focus of the next stage of onshore development operations. In particular, the well temperatures of some deep wells in western Sichuan can reach 150–170℃, some wells in the Qinghai oilfield can reach over 160℃, and some ultra-deep wells in northern Xinjiang can reach over 190℃. In deep, highly abrasive, and hard formations, roller cone bits and hybrid bits are more suitable for drilling; however, roller cone bits face extremely challenging high-temperature problems. High-temperature environments accelerate the aging of rubber sealing materials, affect the lifespan of bearing seals, and restrict the efficient development of oil, gas, and geothermal resources.

[0003] To address the aging problem of rubber seal materials in drill bit bearings, fluororubber and perfluoroether rubber, which have higher temperature resistance, are generally used instead of hydrogenated nitrile rubber. Ordinary fluororubber typically withstands temperatures up to 220℃, but if drill bits need to withstand higher temperatures, the bearings must use perfluoroether rubber with even higher temperature resistance. Although perfluoroether rubber can withstand temperatures up to 300℃, in actual use, it has been found that as the temperature rises, the edges of the elastic sealing gasket are prone to cracking or shearing damage, leading to seal failure. Summary of the Invention

[0004] This application provides a high-temperature resistant drill bit to solve the problem in related technologies that the edges of elastic sealing gaskets made of perfluoroether rubber are prone to cracking or shear damage in a high-temperature environment of 300°C, leading to sealing failure.

[0005] In a first aspect, a high-temperature resistant drill bit is provided, comprising a tooth journal and a toothed cone rotatably connected to the tooth journal, wherein a sealing groove is provided at the root of the tooth journal, and a sealing assembly is provided between the tooth journal and the toothed cone, the sealing assembly comprising: A bushing, fitted inside the shaft hole cavity of the toothed wheel; A rigid ring is movably connected to the end face of the bushing; An elastic sealing gasket is disposed in the sealing groove, which seals the rigid ring and the toothed journal along the axial direction of the toothed journal. The contact surface between the gasket and the bottom of the sealing groove is a concave curved surface, and its radial width along the toothed journal is smaller than the width of the bottom of the sealing groove. An elastic power supply ring is disposed between the inner wall of the rigid ring near the tooth bearing journal and the tooth bearing journal.

[0006] In some embodiments, the contact surface width between the rigid ring and the elastic sealing gasket is L0; The contact surface width between the elastic sealing gasket and the rigid ring is L1; Where 1.0≤L0 / L1≤1.4.

[0007] In some embodiments, the radial width of the resilient sealing gasket is set to L2; The bottom width of the sealing groove is set to L3; Among them, L2 and L3 satisfy 0.50mm≤L3-L2≤2.00mm.

[0008] In some embodiments, the inner diameter of the elastic sealing gasket in its free state is d; The diameter of the tooth palm journal is D; Where 0 < Dd ≤ 1.50 mm and d / D ≤ 0.99.

[0009] In some embodiments, the angle between the concave curved surface and the bottom surface of the sealing groove is α, and 5°≤α≤50°.

[0010] In some embodiments, the edge of the rigid ring that contacts the resilient sealing gasket is rounded.

[0011] In some embodiments, the radius of the fillet is R and 0.25mm < R < 1.00mm.

[0012] In some embodiments, the contact surface between the elastic sealing gasket and the rigid ring is surface C1; The side of the elastic sealing gasket closest to the lubricating oil is surface C2; The side of the elastic sealing gasket away from the lubricating oil is surface C3; The C1 surface and the C2 surface are connected by an inclined transition surface A, and the angle between the transition surface A and the C2 surface is β1, and 15° < β1 < 90°. The C1 surface and the C3 surface are connected by an inclined transition surface B. The angle between the transition surface B and the C3 surface is β2, where 15°≤β2<90° and β2<β1. The C2 surface and the C3 surface are parallel to the sidewall of the sealing groove, and the C2 surface is in contact with the sealing groove.

[0013] In some embodiments, the sealing assembly further includes a bushing fixedly connected to the inner wall of the roller cone, and the rigid ring sealingly connected to the bushing.

[0014] In some embodiments, the resilient sealing gasket and resilient power supply ring are made of perfluoroether rubber.

[0015] In some embodiments, the rubber hardness of the elastic sealing gasket is not less than 80 Shore A.

[0016] This application provides a high-temperature resistant drill bit. Due to the fit between the inner diameter of the sealing gasket and the shaft diameter, and the fit between the radial width of the sealing gasket and the bottom width of the sealing groove, the elastic sealing gasket is prevented from overflowing the sealing groove at high temperatures, while providing adequate deformation space to prevent it from being squeezed and broken. The concave curved surface of the elastic sealing gasket reduces its axial compression ratio. When the roller cone moves axially, the concave curved surface acts as a buffer. As the temperature rises, the elastic sealing gasket expands in volume, and the concave curved surface deforms under the axial sealing force, mitigating the risk of excessive axial sealing force at high temperatures due to expansion and causing damage to the elastic sealing gasket, further improving sealing performance. The contact plane between the rubber sealing gasket and the metal-sealed sealing ring is connected via a transition surface to the outer diameter side of the sealing gasket near the mud side and the inner diameter side of the sealing gasket near the grease side, respectively, avoiding the cutting action of the metal sealing ring on the rubber. By employing the above technologies, the high-temperature bearing metal seal structure can adapt to the large volume expansion of perfluoroelastomer rubber at high temperatures, while ensuring that the perfluoroelastomer rubber gasket does not break down from room temperature to 300°C, thus improving the service life of the seal at high temperatures. 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 longitudinal cross-sectional structure of a high-temperature resistant drill bit provided in an embodiment of this application; Figure 2 for Figure 1 Enlarged structural diagram at point M; Figure 3 This is a schematic diagram of the rigid ring cross-sectional structure in a high-temperature resistant drill bit provided in an embodiment of this application; Figure 4 Schematic diagram of the cross-sectional structure of the elastic sealing gasket in the high-temperature drill bit provided in the embodiments of this application. Figure I ; Figure 5 Schematic diagram of the cross-sectional structure of the elastic sealing gasket in the high-temperature drill bit provided in the embodiments of this application. Figure II ; In the diagram: 1. Toothed journal; 101. Sealing groove; 2. Toothed wheel; 3. Sealing cavity; 4. Sealing assembly; 401. Rigid ring; 402. Elastic sealing gasket; 4021. Concave surface; 403. Elastic power supply ring; 404. Sleeve; 5. Steel ball; 6. Plug pin; 7. Lubricating grease channel; 8. Toothed journal. Detailed Implementation

[0019] 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.

[0020] Existing high-temperature drill bit bearing seals typically employ a composite sealing structure consisting of a metal sealing ring, an elastic power supply ring, and an elastic sealing gasket. To meet the increasingly demanding high-temperature operation requirements of deep and ultra-deep wells, the elastic power supply ring and elastic sealing gasket are often made of perfluoroelastomer rubber with higher temperature resistance. However, the applicant has discovered that while perfluoroelastomer rubber exhibits excellent basic temperature resistance, its volume effect at extreme high temperatures becomes a key factor contributing to seal failure.

[0021] Experimental data show that the appearance and performance of the elastic gasket of the sealing component using perfluoroether rubber are good in the initial process of rising from room temperature to 300℃; however, when the temperature reaches 300℃, the edge of the elastic gasket cracks or is sheared, resulting in sealing failure.

[0022] Analysis revealed that this is because perfluoroelastomer rubber exhibits a much higher volume expansion rate than ordinary rubber at temperatures exceeding 200°C. Traditional sealing structures do not adequately consider volume changes in their design; for example, limitations exist in the volume of the sealing groove, the structure of the elastic gasket, and the fit clearance of the metal sealing ring. This results in the elastic gasket having nowhere to release stress after expanding at high temperatures. Excessive volume expansion causes the gasket to suffer immense internal compressive stress within the sealing groove. Simultaneously, under the dynamic shear force caused by the movement of the rollers, it is highly susceptible to cracking or shear damage at the sharp edge of the metal ring or the groove opening, ultimately leading to slurry intrusion into the bearing and complete loss of sealing function.

[0023] In view of this, the present application provides a high-temperature resistant drill bit that can solve the problem in the related art that perfluoroether rubber is prone to cracking due to thermal expansion in a high-temperature environment of 300°C, leading to seal failure.

[0024] like Figure 1As shown, a high-temperature resistant drill bit includes a roller cone 2 and a toothed journal 8. The roller cone 2 has a bearing hole, and the toothed journal 8 has a toothed journal journal 1. A sealing groove 101 is formed at the rear root of the toothed journal journal 1, and the axis of the sealing groove 101 is parallel to the axial direction of the toothed journal journal 1. The roller cone 2 is sleeved with the toothed journal journal 1 through the bearing hole to form a bearing structure. A bushing 404 is embedded in the inner cavity of the shaft hole of the roller cone 2. After the steel ball 5 is inserted into the sliding bearing structure through the hole of the plug pin 6, the plug pin 6 is inserted into the hole of the plug pin 6 and welded to fix it. The steel ball 5 can hold the roller cone 2 axially on the toothed journal journal 1. The toothed journal 8 has a lubricating grease channel 7, 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 regulated by the oil storage pressure balancing system to squeeze out some of the lubricating grease from the oil storage sac, thereby achieving the function of regulating the pressure difference inside and outside the bearing cavity. The bearing end is sealed by a high-temperature resistant bearing metal sealing assembly 4 to prevent mud from entering the bearing.

[0025] Furthermore, a sealing cavity 3 is provided between the toothed journal 1 and the toothed cone 2, and the sealing cavity 3 is connected to the sealing groove 101. A sealing assembly 4 is disposed in the sealing cavity 3 and the sealing groove 101. The sealing assembly 4 includes: The insert is 404 and is embedded in the inner cavity of the shaft hole of the gear 2; The rigid ring 401 is movably connected to the end face of the bushing 404, that is, the rigid ring 401 and the end face of the bushing 404 are rotated and sealed together, and are made of hard alloy or 9Cr18 and other materials. The elastic sealing gasket 402 is disposed in the sealing groove 101. It seals the rigid ring 401 and the toothed journal 1 along the axial direction of the toothed journal 1. Its contact surface with the bottom of the sealing groove 101 is a concave curved surface 4021, and its radial width along the toothed journal is less than the width of the bottom of the sealing groove 101. An elastic energy supply ring 403 is disposed between the inner wall of the rigid ring 401 near the tooth bearing journal 1 and the tooth bearing journal 1. The elastic energy supply ring 403 is disposed on the inner wall of the rigid ring 401, that is, on the side of the rigid ring 401 near the tooth bearing journal 1. The cross-section of the rigid ring 401 is a trapezoidal structure. The elastic energy supply ring 403 continuously provides thrust to the wedge-shaped edge of the trapezoidal rigid ring 401, so that the rigid ring 401 always forms a dynamic seal with the bushing 404.

[0026] During operation, as the drill bit rotates, the rigid ring 401 rotates relative to the bushing 404, forming a dynamic sealing surface. At high temperatures, the elastic power supply ring 403 and the elastic sealing gasket 402 continuously apply thrust to the rigid ring 401, ensuring that the end face of the rigid ring 401 remains in contact with the end face of the bushing. This dynamic compensation mechanism ensures that even when high temperatures cause the parts to expand or the drill bit to experience slight movement, the two metal surfaces will not separate, maintaining an effective seal. Simultaneously, severe vibrations and pressure fluctuations during drilling are transmitted to the root of the rigid ring 401 through the journal. At this time, the elastic sealing gasket 402, installed in the sealing groove 101 at the root of the journal 1 and the lower end face of the rigid ring 401, acts as a buffer layer, absorbing high-frequency vibrations and impact energy through its elastic deformation, preventing the rigid ring 401 from cracking due to rigid collisions.

[0027] The above design provides deformation space for the elastic gasket to expand at high temperatures, especially for perfluoroether rubber materials near 300°C. When the temperature rises and the rubber expands thermally, the concave surface can adapt to the axial sealing force, effectively absorbing and mitigating the internal stress caused by the increased volume, thus preventing stress concentration and rupture of the elastic gasket 402. Simultaneously, the radial width difference design and the matching design between the inner diameter of the elastic gasket 402 and the diameter of the tooth bearing journal 1 ensure that the expanded elastic gasket 402 will not overflow from the sealing groove 101 or be excessively compressed by the groove wall, maintaining the integrity and tight fit of the sealing interface. This combined structure significantly enhances the adaptability and reliability of the sealing assembly 4 under complex conditions such as high temperature, high pressure, and axial movement of the toothed wheel 2. It fundamentally solves the technical problem of traditional perfluoroether rubber seals being easily damaged by high-temperature expansion, leading to mud intrusion into the bearing and failure. This increases the withstand temperature of the drill bit bearing seal to 300°C, significantly extending the service life and operational safety of the drill bit in high-temperature environments such as deep wells, ultra-deep wells, and geothermal resource development.

[0028] Furthermore, the elastic sealing gasket 402 and the elastic power supply ring 403 are made of perfluoroether rubber; Furthermore, the rubber hardness of the elastic sealing gasket 402 is not less than 80 Shore A.

[0029] Perfluoroelastomer rubber was selected as the material for the elastic sealing gasket 402 and the elastic power supply ring 403. This fully utilizes the material's inherent high-temperature resistance, oil resistance, and chemical resistance, enabling it to operate stably in extreme downhole environments exceeding 220°C and even reaching 300°C, fundamentally overcoming the shortcomings of ordinary rubber materials that are prone to high-temperature aging and failure. Simultaneously, the rubber hardness of the elastic sealing gasket 402 was explicitly specified to be no less than 80 Shore A, ensuring that the sealing ring maintains sufficient mechanical strength and rigidity at high temperatures. This provides the necessary elasticity to maintain good sealing contact pressure while effectively resisting excessive deformation, crushing damage, or cutting by metal parts due to high-temperature softening. This optimized combination of material and hardness allows the sealing ring to alleviate stress through moderate deformation while maintaining structural integrity and the durability of its sealing function when subjected to high-temperature expansion, axial movement, and system pressure fluctuations. This achieves long service life and high reliability of the drill bit bearing sealing system under ultra-high temperature conditions.

[0030] Furthermore, the contact surface width between the rigid ring 401 and the elastic sealing gasket 402 is L0; The contact surface width between the elastic sealing gasket 402 and the rigid ring 401 is L1; Where 1.0≤L0 / L1≤1.4.

[0031] The above settings provide a more uniform and stable axial clamping force distribution during sealing, avoiding edge stress concentration or insufficient local sealing pressure caused by mismatched contact surface widths. Especially under high-temperature conditions, when the perfluoroelastomer rubber sealing ring undergoes thermal expansion and softening, this proportional relationship helps maintain the integrity of the sealing interface, preventing a reduction in effective sealing area or misalignment of the sealing line due to rubber deformation. This ensures the reliability and consistency of the seal across the entire operating temperature range from room temperature to 300°C, effectively improving the adaptability of the sealing assembly to temperature changes.

[0032] Furthermore, the edges where the rigid ring 401 contacts the elastic sealing gasket 402 are rounded. Furthermore, the radius of the fillet is R and 0.25mm < R < 1.00mm.

[0033] The above-mentioned design eliminates stress concentration points and micro-cutting effects that may occur at the metal edges. Under high-temperature conditions, the perfluoroelastomer rubber sealing ring softens significantly, reducing its mechanical strength and resistance to sharp objects. Without a rounded transition, the hard metal sharp edge can easily cut into or scratch the rubber surface like a knife when the sealing ring is subjected to axial pressure, thermal expansion, or friction from the toothed gear, leading to localized damage and seal failure. A rounded radius within a specific range (R > 0.25 mm) is sufficient to evenly distribute the contact stress onto a small curved surface, forming a smooth transition contact area that effectively protects the softened rubber surface. At the same time, the upper limit of the rounded radius (R < 1.00 mm) ensures that the chamfer does not excessively reduce the effective sealing contact area or change the distribution of sealing pressure, thereby providing reliable protection while maintaining the necessary clamping force and sealing performance at the axial sealing interface, significantly improving the durability and reliability of the sealing assembly 4 under high temperature and dynamic load.

[0034] Furthermore, the radial width of the elastic sealing gasket 402 is set to L2; The bottom width of the sealing groove 101 is set to L3; Among them, L2 and L3 satisfy 0.50mm≤L3-L2≤2.00mm.

[0035] The above-described design provides precise and necessary deformation space for the radial thermal expansion of the elastic gasket 402 at high temperatures. This ensures that the elastic gasket 402 is easy to assemble and correctly positioned during installation at room temperature, while allowing the perfluoroelastomer rubber material to expand safely as the operating temperature rises to 300°C. This prevents excessive internal stress caused by rigid compression from the sidewall of the sealing groove 101, effectively preventing shear cracking or structural damage to the elastic gasket 402. Simultaneously, this gap range is optimized to accommodate the expansion without being excessive, preventing excessive displacement or torsion of the sealing ring within the groove. This ensures that the axial sealing interface between the elastic gasket 402 and the rigid ring 401 remains stably aligned and in effective contact, thus maintaining durable and reliable sealing performance under high temperature, high pressure, and dynamic operating conditions.

[0036] Furthermore, the inner diameter of the elastic sealing gasket 402 in its free state is d; The diameter of the palmar neck 1 is D; Where 0 < Dd ≤ 1.50 mm and d / D ≤ 0.99.

[0037] By defining the relationship between the inner diameter d of the elastic sealing gasket 402 in its free state and the diameter D of the toothed journal 1, i.e., satisfying 0 < Dd ≤ 1.50 mm and d / D ≤ 0.99, a reasonable radial interference fit is set for the sealing ring. This ensures that the elastic sealing gasket 402 can tightly fit onto the toothed journal 1 after assembly, generating the necessary initial radial clamping force, thereby forming an effective radial seal even at low temperatures. Simultaneously, the upper limit control of the interference fit (Dd ≤ 1.50 mm) avoids excessive stretching or compression damage to the rubber during installation or after high-temperature expansion due to excessive interference fit, ensuring the structural integrity and continuous stability of the sealing function of the elastic sealing gasket 402 throughout the entire operating temperature range.

[0038] Given the limited space and compact structure of the drill bit sealing groove, and the extremely limited radial clearance, the precise design of the interference fit is crucial. By setting an appropriate initial interference fit at room temperature, assembly reliability is ensured, while also allowing reasonable space for volume expansion at high temperatures, thus maintaining a stable sealing interface even under extreme operating conditions.

[0039] Furthermore, such as Figure 5 As shown, the angle between the concave curved surface 4021 and the bottom surface of the sealing groove 101 is α, and 5°≤α≤50°.

[0040] By controlling the angle α between the concave curved surface 4021 and the bottom surface of the sealing groove 101 within the range of 5° to 50°, optimized geometric guidance is provided for the deformation behavior of the elastic sealing gasket 402. This specific angled concave curved surface design allows the elastic sealing gasket 402 to produce controllable and uniform radial deformation when compressed by axial sealing force, rather than simple overall compaction. When the roller 2 experiences axial movement or temperature rise causes pressure changes in the sealing system, this concave structure acts as a mechanical buffer, effectively absorbing and dispersing impact energy and reducing stress concentration within the rubber. More importantly, when the sealing ring expands in volume at high temperatures, this concave structure allows the rubber material to flow orderly and with low resistance into the concave space, thus providing additional, controllable accommodation space for thermal expansion. This alleviates the huge internal stress caused by the rigid restriction of volume expansion, fundamentally avoiding the risk of shearing or tearing of the elastic sealing gasket 402 under the combined effects of high compression and high expansion, ensuring the long-term integrity of the sealing interface under dynamic and extreme thermal conditions.

[0041] Furthermore, the contact surface between the elastic sealing gasket 402 and the rigid ring 401 is surface C1; The side of the elastic sealing gasket 402 closest to the lubricating oil is surface C2; The side of the elastic sealing gasket 402 furthest from the lubricating oil is surface C3, that is, the side closest to the mud is surface C3. Among them, the C1 surface and the C2 surface are connected by an inclined transition surface A. The angle between the transition surface A and the C2 surface is β1, and 15° < β1 < 90°. Surface C1 and surface C3 are connected by an inclined transition surface B. The angle between the transition surface B and surface C3 is β2, where 15°≤β2<90° and β2<β1. Surfaces C2 and C3 are parallel to the sidewalls of the sealing groove 101, and surface C2 is in contact with the sealing groove 101. That is, surface C2 is parallel to and in close contact with the side of the sealing groove 101 near the toothed shaft journal 1, while surface C3 is parallel to the side of the sealing groove 101 near the mud side.

[0042] By using inclined transition surfaces A and B, the structural response of the elastic sealing gasket 402 under complex stress conditions is significantly optimized. These transition surfaces break the stress concentration inflection points that may be formed by right-angle connections, so that when the elastic sealing gasket 402 is subjected to axial clamping force, lateral extrusion force due to high temperature expansion, or dynamic shear force caused by the movement of the roller 2, the stress can be effectively dispersed and transferred along the smooth inclined surfaces, avoiding the risk of local tearing or damage at the corners.

[0043] It is particularly important to note that because the elastic sealing gasket 402 faces the bottom mud directly from the lubricating oil side (i.e., surface C3), this side not only bears mechanical stress but is also more susceptible to mud erosion and intrusion. During temperature increases, the elastic sealing gasket 402 expands and moves towards the mud side, making it vulnerable to cutting action by the rigid ring 401, thus facing a higher risk of shear failure under dynamic conditions. Therefore, the angle design of the transition surfaces on both sides needs to be different: the angle β2 between the transition surface B (closer to the mud side) and surface C3 should be smaller than the angle β1 between the transition surface A (closer to the lubricating oil side) and surface C2, i.e., β2 < β1. This differentiated design makes the transition on the mud side smoother and the stress transition more uniform, more effectively resisting external shear forces. This significantly improves the durability and reliability of the elastic sealing gasket 402 under harsh conditions while ensuring sealing performance.

[0044] Meanwhile, the C2 and C3 surfaces are parallel to the corresponding sides of the sealing groove, ensuring that the elastic sealing gasket 402 can uniformly transfer stress to the groove wall when subjected to axial compression force and high-temperature expansion lateral force, avoiding local stress concentration caused by angular deviation; the tight fit between the C2 surface and the groove wall effectively restricts the displacement and rotation of the elastic sealing gasket 402 in the circumferential direction, ensuring that the sealing interface between it and the rigid ring 401 is always aligned, maintaining the continuity and stability of the sealing line.

[0045] To aid in understanding the technical solution of this invention, a specific embodiment is provided below to illustrate the positive effect of the following parameters: 0.50mm≤L3-L2≤2.0mm, 0<Dd≤1.50mm and d / D=0.99, 1.0≤L0 / L1≤1.4, 15°<β1<90°, 15°≤β2<90° and β2<β1, on overcoming the cracking of perfluoroether rubber elastic gaskets caused by high-temperature expansion. This embodiment is merely an example and does not constitute a limitation on the scope of protection of this invention.

[0046] Example 1: The sealing assembly in this embodiment is constructed strictly according to the key dimensions and material requirements of the present invention. Specific parameters are as follows: the bottom width L3 of the metal sealing groove 101 is 3.2 mm; the radial width L2 of the elastic sealing gasket 402 is 2.35 mm; the inner diameter d of the elastic sealing gasket 402 is 43.1 mm; the diameter D of the toothed journal 1 is 43.6 mm; the width L1 of the contact plane C1 between the elastic sealing gasket 402 and the rigid ring 401 is 1.15 mm; the width L0 of the contact plane between the rigid ring 401 and the elastic sealing gasket 402 is 1.4 mm; and the elastic sealing gasket 402... The contact area with the metal sealing groove 101 is a concave curved surface 4021. The angle α between the concave curved surface 4021 and the bottom surface of the metal sealing groove 101 is 25°. The angle β1 formed by the transition surface A and the tangent of the outer diameter side surface C2 of the elastic sealing gasket 402 near the lubricating oil side is 40°. The angle β2 formed by the transition surface B and the tangent of the inner diameter side surface C3 of the elastic sealing gasket 402 away from the grease side is 30°. The chamfer R of the contact between the rigid ring 401 and the elastic sealing gasket 402 is 0.5mm. The elastic sealing gasket 402 is made of perfluoroether rubber material with a hardness of 85 Shore A.

[0047] To verify the high-temperature sealing performance of the above structure, simulated working condition tests were conducted. The drill bit bearing unit equipped with the sealing component 4 was placed in a high-temperature test chamber and uniformly heated from room temperature to 280°C and held at that temperature for 10 minutes to ensure sufficient thermal expansion of the material. Subsequently, under high-temperature conditions, an axial load was applied to the sealing interface using an electronic tensile testing machine to simulate the axial movement of the drill bit during operation, and five cycles of load-unload tests were performed. After the test, the elastic sealing gasket 402 was inspected, and the results showed that its appearance was intact, with no visible damage, tearing, or overflow from the sealing groove. The minimum sealing specific pressure at 280°C was 3.5 MPa, meeting the sealing requirements, and the dynamic sealing reliability verification at 280°C was successfully passed.

[0048] Based on the above embodiments, research has found that the fit dimensions between the inner diameter of the elastic sealing gasket 402 and the diameter of the toothed journal 1, the fit dimensions between the radial width of the elastic sealing gasket 402 and the bottom width of the metal sealing groove 101, the width of the contact plane between the elastic sealing gasket 402 and the rigid ring 401, the width of the contact plane between the rigid ring 401 and the elastic sealing gasket 402, the angle between the concave curved surface of the elastic sealing gasket 402 and the bottom surface of the metal sealing groove 101, and the hardness of the elastic sealing gasket 402 have a significant impact on the perfluoroether rubber sealing gasket's ability to withstand high temperatures of 280°C and avoid damage due to high-temperature expansion.

[0049] To further reveal the technical contribution of each parameter and explain why the aforementioned series of conditions must be met simultaneously, several comparative examples are provided below, as shown in the table:

[0050] Comparative Example 1: In this comparative example, L3-L2 is 0.3 mm, which is less than the lower limit of 0.5 mm. All other structural dimensions, materials and test conditions are exactly the same as in Example 1.

[0051] After testing, it was found that the elastic sealing gasket 402 was cut and damaged by the outer step of the sealing groove 101. At 280℃, the minimum sealing pressure was 1.0MPa, indicating seal failure. This shows that when the difference between the width of the sealing groove and the radial width of the elastic sealing gasket is too small, it cannot provide sufficient radial space to accommodate the volume expansion of the perfluoroether rubber at high temperatures. The over-expanded rubber material generates huge internal stress in the confined space, and under the combined action of axial compression force and dynamic shear force, it is forced into the groove gap, eventually being cut and damaged by the sharp groove edge, leading to seal failure.

[0052] Comparative Example 2: In this comparative example, the difference from Example 1 is that L3-L2 is set to 2.5mm, which is greater than the upper limit of 2.0mm. All other structural dimensions, materials and test conditions are exactly the same as in Example 1.

[0053] After testing, it was found that the elastic gasket 402 flipped inward within the sealing groove, and the minimum sealing pressure dropped to 0.5 MPa at 280℃, indicating seal failure. This shows that when the difference between the sealing groove width and the radial width of the elastic gasket is too large, the elastic gasket loses effective radial constraint within the groove. Under the combined action of axial clamping force, high-temperature expansion stress, and dynamic load caused by the movement of the toothed conduit, the excessive gap causes the gasket to become unstable and deform, eventually flipping over. The flipped gasket cannot maintain normal contact with the rigid ring and the sealing groove wall, leading to damage to the sealing interface, a sharp drop in sealing pressure, and ultimately, seal failure.

[0054] Comparative Example 3: In this comparative example, the difference from Example 1 is that Dd is set to -0.1mm, that is, the inner diameter of the elastic sealing gasket 402 in the free state is greater than the diameter of the tooth palm journal 1, forming a negative interference (clearance fit). All other structural dimensions, materials and test conditions are exactly the same as in Example 1.

[0055] After testing, it was found that the elastic sealing gasket 402 was cut and damaged by the outer step (groove edge) of the sealing groove 101. At 280℃, the minimum sealing pressure was 0.8MPa, indicating seal failure. This shows that when there is a lack of necessary radial interference (Dd≤0) between the elastic sealing gasket and the journal, the gasket cannot tightly fit against the journal surface, resulting in insufficient initial radial sealing force. Under high-temperature conditions, although the perfluoroelastomer rubber expands in volume, the presence of the initial gap prevents the establishment of effective contact pressure between the gasket and the journal. Simultaneously, the gasket, having lost its radial positioning, moves radially under the action of axial clamping force and dynamic shear force, being squeezed into the gap between the sealing groove and the rigid ring, and ultimately cut and damaged by the groove edge, leading to seal failure.

[0056] Comparative Example 4: In this comparative example, the difference from Example 1 is that Dd is set to 1.7 mm, which exceeds the upper limit of 1.5 mm. All other structural dimensions, materials and test conditions are exactly the same as in Example 1.

[0057] During initial installation, the elastic gasket 402 flipped and was sheared by the rigid ring 401, causing pre-existing damage. The minimum sealing pressure under 280℃ testing conditions was 0.4 MPa, indicating seal failure. This demonstrates that when the radial interference exceeds the reasonable upper limit (Dd>1.5mm), excessive interference causes excessive compression deformation of the elastic gasket during assembly. Due to the narrow sealing groove space, excessive interference causes the gasket to lose its stable shape during installation, flipping and being sheared by the edge of the rigid ring. Although the expansion of the perfluoroelastomer at high temperatures may compensate for the initial damage to some extent, the damaged gasket cannot maintain a complete sealing interface, ultimately leading to seal failure.

[0058] Comparative Example 5: In this comparative example, the difference from Example 1 is that the hardness of the elastic sealing gasket 402 is set to 75 Shore A, which is lower than the lower limit of 80 Shore A. All other structural dimensions, materials and test conditions are exactly the same as in Example 1.

[0059] After testing, it was found that the elastic sealing gasket 402 exhibited circumferential cracking, and the minimum sealing pressure dropped to 0.2 MPa at 280°C, resulting in seal failure. This indicates that when the rubber hardness of the elastic sealing gasket is below 80 Shore A, the material's mechanical strength and resistance to deformation at high temperatures are insufficient. At 280°C, the excessively softened perfluoroether rubber cannot effectively resist axial clamping force, its own thermal expansion stress, and the dynamic shear force caused by the movement of the toothed conduit. Fatigue cracks develop at stress concentration points, eventually leading to a penetrating circumferential crack. The ruptured gasket loses its axial support capacity for the rigid ring and the integrity of the sealing interface, resulting in a sharp drop in sealing pressure and complete seal failure.

[0060] Comparative Example 6: In this comparative example, the difference from Example 1 is that L3-L2 is set to 0.3mm (less than the lower limit of 0.5mm), and Dd is set to -0.1mm (negative interference, i.e., the inner diameter of the elastic sealing gasket is greater than the diameter of the tooth palm journal). All other structural dimensions, materials and test conditions are exactly the same as in Example 1.

[0061] After the test, it was found that the elastic sealing gasket 402 was cut and damaged by the outer step of the sealing groove 101. At 280℃, the minimum sealing pressure was 0.7MPa, and the seal failed. Combining the test results of Comparative Example 1 (only L3-L2 is too small) and Comparative Example 3 (only Dd is negative), it is further shown that the two adverse factors of insufficient radial clearance and lack of radial interference have a superimposed effect: on the one hand, the clearance is too small (L3-L2=0.3mm) and cannot provide enough space to accommodate high-temperature expansion; on the other hand, the negative interference (Dd=-0.1mm) makes the sealing gasket lack effective clamping to the journal in the initial state, and it is more likely to overflow the sealing groove after expansion at high temperature. The combined effect of the two causes the sealing gasket to be more unstable at high temperature, squeezed into the groove gap, and finally cut and broken under the synergistic influence of the two defects, resulting in seal failure.

[0062] Comparative Example 7: The difference from Example 1 is that L3-L2 is set to 0.3mm (less than the lower limit of 0.5mm) and Dd is set to 1.7mm (more than the upper limit of 1.5mm). All other structural dimensions, materials and test conditions are exactly the same as in Example 1.

[0063] During initial installation, the elastic gasket 402 flipped and was sheared by the rigid ring 401, causing pre-existing damage. The minimum sealing pressure under 280℃ test conditions was 0.3MPa, indicating seal failure. Further analysis of the test results from Comparative Example 1 (only L3-L2 were too small) and Comparative Example 4 (only Dd was too large) further illustrates that the combined effects of insufficient radial clearance and excessive radial interference exacerbated the gasket failure risk: on the one hand, insufficient clearance could not provide enough space for high-temperature expansion; on the other hand, excessive interference caused the gasket to undergo excessive compression deformation during installation, losing its stable shape and flipping, ultimately being sheared and broken by the rigid ring. This demonstrates that the matching design of radial clearance and radial interference is crucial. A single parameter within a reasonable range cannot compensate for a significant deviation in the other parameter; both must work together to meet design requirements to ensure the reliability of the sealing assembly under assembly and high-temperature conditions.

[0064] Comparative Example 8: The difference from Example 1 is that L3-L2 is set to 2.5mm (exceeding the upper limit of 2.0mm), and Dd is set to -0.1mm (negative interference, that is, the inner diameter of the elastic sealing gasket is greater than the diameter of the tooth palm journal). All other structural dimensions, materials and test conditions are exactly the same as in Example 1.

[0065] After testing, it was found that the elastic gasket 402 was under unbalanced stress, exhibiting irregular deformation. At 280℃, the minimum sealing pressure dropped to 0.6 MPa, resulting in seal failure. Further analysis of the test results from Comparative Example 2 (only L3-L2 was excessive) and Comparative Example 3 (only Dd was negative) further illustrates that the combined effects of excessive radial clearance and insufficient radial interference caused the gasket to lose effective stress balance within the groove. On one hand, the excessive clearance (L3-L2=2.5mm) resulted in insufficient radial constraint on the gasket within the groove, making it prone to instability and displacement. On the other hand, the negative interference (Dd=-0.1mm) prevented the gasket from tightly adhering to the journal surface, losing its initial radial positioning capability. The combined effect of these two factors led to a severe imbalance in the stress state of the gasket under the combined action of axial clamping force, high-temperature expansion stress, and dynamic shear force, resulting in irregular deformation and localized damage to the gasket. This inability to maintain a stable sealing interface ultimately led to seal failure. This indicates that sufficient radial constraint and reliable initial positioning are necessary conditions for ensuring the stress balance of the gasket, and neither can be lacking.

[0066] Comparative Example 9: The difference from Example 1 is that L3-L2 is set to 2.5mm (exceeding the upper limit of 2.0mm), and Dd is set to 1.7mm (exceeding the upper limit of 1.5mm). All other structural dimensions, materials and test conditions are exactly the same as in Example 1.

[0067] During initial installation, the elastic gasket 402 flipped and was sheared by the rigid ring 401, causing pre-existing damage. The minimum sealing pressure under 280℃ test conditions was 0.4 MPa, indicating seal failure. Further analysis of the test results from Comparative Example 2 (only L3-L2 was excessive) and Comparative Example 4 (only Dd was excessive) further illustrates that the combined effects of excessive radial clearance and excessive radial interference compromised the gasket's stability from different dimensions: on the one hand, excessive clearance (L3-L2=2.5mm) resulted in insufficient radial restraint within the groove, making the gasket prone to displacement; on the other hand, excessive interference (Dd=1.7mm) subjected the gasket to excessive compression during installation, causing it to lose its stable shape, flip, and be sheared by the rigid ring. The combined effect of these two factors resulted in irreversible structural damage to the gasket during the assembly stage. This indicates that both radial clearance and radial interference must be controlled within reasonable ranges simultaneously; significant deviations from either parameter can lead to assembly damage, and the two cannot compensate for each other.

[0068] Comparative Example 10: The difference from Example 1 is that L3-L2 is set to 0.3mm (less than the lower limit of 0.5mm), Dd is set to -0.1mm (negative interference, i.e. the inner diameter of the elastic sealing gasket is greater than the diameter of the tooth palm journal), and the hardness of the elastic sealing gasket 402 is set to 75 Shore A (less than the lower limit of 80 Shore A). All other structural dimensions, materials and test conditions are exactly the same as in Example 1.

[0069] After the test, it was found that the elastic sealing gasket 402 was partially cut and damaged by the outer step of the sealing groove 101. At 280℃, the minimum sealing pressure dropped to 0.3MPa, and the seal failed. Combined with the test results of Comparative Example 1 (only L3-L2 is too small), Comparative Example 3 (only Dd is negative), and Comparative Example 5 (only hardness is too low), it is further illustrated that the three adverse factors of insufficient radial clearance, lack of radial interference, and excessively low material hardness have a serious superimposed effect: the clearance is too small (L3-L2=0.3mm) and cannot provide space for high-temperature expansion; the negative interference (Dd=-0.1mm) causes the sealing gasket to lose its initial radial positioning ability; and the excessively low hardness (75 Shore A) causes the material to soften excessively at high temperatures and its mechanical strength to decrease significantly. The combined effect of these three defects causes the sealing gasket to completely lose its structural stability under high-temperature conditions: the excessively softened material is easily deformed under axial compression and dynamic shear forces, and under the constraint of insufficient clearance, it is forced into the groove, eventually being cut and damaged by the sharp edge of the groove, resulting in a complete loss of sealing performance. This indicates that structural parameters and material properties must work together to meet design requirements. Severe defects in any dimension can be amplified under the coupling of multiple factors, leading to premature seal failure.

[0070] Comparative Example 11: The difference from Example 1 is that Dd is set to 0.3 mm, which is still greater than 0, but d / D = 0.993, which is greater than the limit of 0.99. This means that the initial radial clamping force is weakened. At the same time, the hardness of the elastic sealing gasket 402 is set to 75 Shore A (below the lower limit of 80 Shore A). The other parameters are consistent with those of Example 1.

[0071] After testing, it was observed that the elastic gasket 402 partially overflowed from the metal sealing groove 101, and significant shearing damage occurred at the junction of the sealing groove 101 and the overflow portion. This proves that even if the absolute value of the radial interference (Dd) meets the requirements, an excessively large d / D ratio (i.e., the inner diameter of the gasket is too large relative to the journal diameter) will still lead to an excessively large initial radial clamping force, causing the gasket to bear excessive compressive stress during assembly. When this structural defect is coupled with insufficient material hardness (75 Shore A), a serious superimposed effect occurs: on the one hand, the excessive initial clamping force causes the gasket to be over-compressed during assembly, resulting in excessive internal stress reserves; on the other hand, the excessively low hardness causes the material to soften excessively at high temperatures, severely reducing mechanical strength. The combined effect of these two factors causes the gasket to lose stability under axial clamping force and dynamic shear force. High-temperature expansion further exacerbates the internal stress, ultimately causing the gasket to be squeezed out of the sealing groove and sheared at the groove edge. This indicates that the upper limit control of the d / D ratio (d / D≤0.99), as a key indicator for measuring radial clamping efficiency, is of equal importance to the lower limit requirement of material hardness. Both must be met in tandem to ensure the structural integrity and sealing reliability of the sealing assembly under high-temperature conditions.

[0072] Comparative Example 12: This comparative example aims to verify the combined effects of an excessively small transition surface angle and an excessively small fillet radius of the metal ring. The angle β2 between the transition surface B and the C3 surface was modified to 10°, and the fillet radius R of the rigid ring 401 was reduced to 0.20 mm (less than the lower limit requirement of 0.25 mm). The remaining parameters are the same as in Example 1.

[0073] After testing, localized shear failure was observed on the outer periphery of the elastic sealing gasket 402 (near the C3 surface), with a minimum sealing pressure of 0.9 MPa at 280℃, indicating reduced sealing reliability. Analysis suggests that this failure was primarily caused by two structural factors: firstly, the transition surface angle was too small (β2=10°), resulting in a larger contact surface width L1 between the elastic sealing gasket 402 and the rigid ring 401, making it easier for the rigid ring 401 to cut the elastic sealing gasket 402; secondly, the metal edge radius of the rigid ring 401 was small (R=0.20mm), making the edge relatively sharp. At high temperatures, the material of the elastic sealing gasket 402 softens, making it even more susceptible to scratches and cuts from this sharp edge. The combined effect of these two factors led to the failure of the sealing ring edge under dynamic load.

[0074] Comparative Example 13: This comparative example aims to verify the effect of an improper width ratio between the contact surfaces of the rigid ring 401 and the elastic sealing gasket 402. The width L1 of the contact surface C1 of the elastic sealing gasket 402 was adjusted to 1.37 mm, and the corresponding contact surface width L0 of the rigid ring 401 was 1.35 mm. At this point, L0 / L1 ≈ 0.985, which is less than the lower limit of 1.0. The remaining parameters are the same as in Example 1.

[0075] After testing, localized rubber damage was observed in the circumferential region of the elastic sealing gasket 402, resulting in a minimum sealing pressure of 0.8 MPa at 280°C and reduced sealing reliability. When the contact surface width of the rigid ring 401 is smaller than that of the elastic sealing gasket 402, uneven overflow deformation of the rubber material may occur under clamping force, especially at the edges. Under cyclic loading, this uneven contact and deformation of the softened rubber at high temperatures can easily lead to fatigue failure, affecting the continuity and stability of the sealing line.

[0076] Comparative Example 14: This comparative example aims to verify the impact of eliminating the concave curved surface design. The contact surface between the elastic sealing gasket 402 and the bottom of the sealing groove 101 is changed to a plane, that is, the concave curved surface 4021 design is eliminated (which can be regarded as α=180°), and all other parameters are kept consistent with Example 1.

[0077] Post-test inspection revealed slight circumferential damage in the middle of the outer diameter surface of the elastic sealing gasket 402. While the minimum sealing pressure at 280℃ was 3.0 MPa, the circumferential damage affected its service life. This highlights the crucial role of the concave surface: planar contact designs cannot provide additional, orderly axial accommodation space during high-temperature expansion, leading to greater internal stress in the rubber under axial and radial constraints. The lack of concave surface also weakens the ability to buffer the axial movement impact of the gear, making the sealing ring more prone to stress concentration and fatigue failure under dynamic conditions.

[0078] In summary, the high-temperature drill bit sealing assembly provided in Embodiment 1 of this application successfully solves the technical problem of perfluoroether rubber sealing rings cracking and failing due to thermal expansion in high-temperature environments above 280°C through a series of synergistically optimized structural designs and material selections. The comparative tests of Examples 1 to 14, on the other hand, demonstrate from the opposite perspective that the various technical parameters defined in this application have clear critical significance and synergistic effects; deviation from any parameter will lead to a decrease in sealing performance or complete failure.

[0079] Comparative Examples 1 to 4 and 6 to 10 demonstrate that the radial clearance (L3-L2) and radial interference (Dd and d / D) must be strictly controlled within the range defined in the claims. If the radial clearance is too small, it cannot accommodate high-temperature expansion, causing the gasket to be cut and damaged by the groove. If the clearance is too large, the gasket loses radial restraint and becomes unstable and flips over. Insufficient radial interference results in a lack of initial clamping force, causing the gasket to shift and be squeezed into the gap at high temperatures. Excessive interference causes flipping and shearing to occur during assembly, resulting in irreversible initial damage. When the above defects exist simultaneously, the failure risk is significantly amplified, indicating that the radial clearance and radial interference must work together to meet the design requirements and cannot compensate for each other.

[0080] Comparative Examples 5, 10, and 11 demonstrate that the rubber hardness of the elastic gasket must be no less than 80 Shore A. Insufficient hardness (75 Shore A, Comparative Example 5) causes the material to soften excessively at high temperatures, making it unable to withstand the combined effects of axial compressive force, thermal expansion stress, and dynamic shear force, resulting in circumferential cracking. When insufficient hardness is combined with structural parameter defects (Comparative Examples 10 and 11), the gasket completely loses its structural stability at high temperatures, leading to more rapid and complete failure.

[0081] Comparative Example 12 demonstrates that an improper transition surface angle leads to uneven stress transmission, causing stress concentration at the edges. Insufficient chamfering of the metal ring causes sharp edges to cut through the softened rubber at high temperatures. In Comparative Example 13, an imbalance in the contact surface width ratio (L0 / L1<1.0) results in uneven distribution of sealing pressure and stress concentration at the edges. In Comparative Example 14, the lack of a concave curved surface causes the gasket to lose its axial deformation buffering capacity, leading to a sharp increase in internal stress at high temperatures. The combined effect of these geometric features is to disperse concentrated stress into a uniform stress field, preventing damage caused by local overload.

[0082] This application further demonstrates through comparative tests of embodiments and comparative examples that any deviation from a key parameter (such as insufficient hardness, improper interference fit, excessively small gap, missing concave surface, etc.) may lead to damage or overflow of the sealing ring at high temperatures, thereby verifying the necessity and synergistic effect of the overall technical solution of this application. The various technical parameters defined in this application—including radial gap 0.50mm≤L3-L2≤2.00mm, radial interference fit 0<Dd≤1.50mm and d / D≤0.99, contact surface width ratio 1.0≤L0 / L1≤1.4, concave curved surface included angle 5°≤ɑ≤50°, transition surface included angle 15°<β1<90°, 15°≤β2<90° and β2<β1, metal ring chamfer 0.25mm<R<1.00mm, rubber hardness ≥80 Shore A—together constitute a complete technical solution. These parameters work together to enable the elastic gasket 402 to withstand temperatures up to 300°C, while providing the necessary space, a reasonable stress release path, and reliable interface contact conditions for the volume expansion of the elastic gasket 402. This fundamentally solves the technical problem of traditional sealing structures being prone to cracking and failure under ultra-high temperature conditions, and significantly improves the high temperature resistance and service life of drill bit bearing seals.

[0083] 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.

[0084] 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.

[0085] 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 high-temperature resistant drill bit, characterized in that, It includes a toothed journal (1) and a toothed wheel (2) rotatably connected to the toothed journal (1). The root of the toothed journal (1) is provided with a sealing groove (101). A sealing assembly (4) is provided between the toothed journal (1) and the toothed wheel (2). The sealing assembly (4) includes: The insert (404) is embedded in the inner cavity of the shaft hole of the toothed wheel (2); A rigid ring (401) is movably connected to the end face of the bushing (404); An elastic sealing gasket (402) is disposed in the sealing groove (101), which seals the rigid ring (401) and the tooth journal (1) along the axial direction of the tooth journal (1). The contact surface between the gasket and the bottom of the sealing groove (101) is a concave curved surface (4021), and its radial width along the tooth journal is smaller than the width of the bottom of the sealing groove (101). An elastic power supply ring (403) is disposed between the inner wall of the rigid ring (401) near the tooth and palm journal (1) and the tooth and palm journal (1).

2. The high-temperature resistant drill bit as described in claim 1, characterized in that: The contact surface width between the rigid ring (401) and the elastic sealing gasket (402) is L0; The contact surface width between the elastic sealing gasket (402) and the rigid ring (401) is L1; Where 1.0≤L0 / L1≤1.

4.

3. The high-temperature resistant drill bit as described in claim 1, characterized in that: The radial width of the elastic sealing gasket (402) is set to L2; The bottom width of the sealing groove (101) is set to L3; Among them, L2 and L3 satisfy 0.50mm≤L3-L2≤2.00mm.

4. The high-temperature resistant drill bit as described in claim 1, characterized in that: The inner diameter of the elastic sealing gasket (402) in its free state is d; The diameter of the tooth palm journal (1) is D; Where 0 < Dd ≤ 1.50 mm and d / D ≤ 0.

99.

5. The high-temperature resistant drill bit as described in claim 1, characterized in that: The angle between the concave curved surface (4021) and the bottom surface of the sealing groove (101) is α, and 5°≤α≤50°.

6. The high-temperature resistant drill bit as described in claim 1, characterized in that: The edge of the rigid ring (401) that contacts the elastic sealing gasket (402) has a rounded corner.

7. The high-temperature resistant drill bit as described in claim 6, characterized in that: The radius of the fillet is R and 0.25mm < R < 1.00mm.

8. The high-temperature resistant drill bit as described in claim 1, characterized in that: The contact surface between the elastic sealing gasket (402) and the rigid ring (401) is surface C1; The elastic sealing gasket (402) has a C2 surface on the side closest to the lubricating oil. The side of the elastic sealing gasket (402) away from the lubricating oil is surface C3; The C1 surface and the C2 surface are connected by an inclined transition surface A, and the angle between the transition surface A and the C2 surface is β1, and 15° < β1 < 90°. The C1 surface and the C3 surface are connected by an inclined transition surface B. The angle between the transition surface B and the C3 surface is β2, where 15°≤β2<90° and β2<β1. The C2 surface and the C3 surface are parallel to the sidewall of the sealing groove (101), and the C2 surface is in contact with the sealing groove (101).

9. The high-temperature resistant drill bit as described in claim 1, characterized in that: The elastic sealing gasket (402) and the elastic power supply ring (403) are made of perfluoroether rubber.

10. The high-temperature resistant drill bit as described in claim 1, characterized in that: The rubber hardness of the elastic sealing gasket (402) is not less than 80 Shore A.

Images