Engine rotating shaft sealing structure

Abstract

The application discloses an engine rotating shaft sealing structure, which comprises a shaft sleeve, a static ring assembly and a dynamic ring. The shaft sleeve is sleeved on the outside of a rotating shaft. The static ring assembly is fixed to the inner wall of the shaft sleeve, is sleeved on the outside of the rotating shaft and is radially provided with a first annular gap from the rotating shaft. The dynamic ring is fixed to the outer wall of the rotating shaft, is radially provided with a second annular gap from the shaft sleeve, is coaxially arranged with the static ring assembly and is provided with a reserved expansion gap between the dynamic ring and the static ring assembly. The application relates to the technical field of rotating shaft sealing. Multiple sets of the sealing structure are arranged in the shaft sleeve, so that multiple sets of narrow and long gaps and irregular baffle-type gaps form a zigzag labyrinth gap. When medium flows through the zigzag labyrinth gap, the medium is throttled, depressurized and vortexed multiple times, and the problem of sealing of a long rotating shaft is effectively solved.

Description

Technical Field

[0001] This invention relates to the field of shaft sealing technology, specifically to an engine shaft sealing structure. Background Technology

[0002] The core function of a shaft seal is to prevent media leakage and block external impurities. There are various types of shaft seals, one of which is the non-contact seal. Non-contact seals involve no direct contact between the sealing element and the shaft, maintaining a gap. They rely on fluid dynamics, centrifugal force, or labyrinth barrier to achieve sealing. They offer advantages such as no wear and long service life, making them suitable for high-speed applications where friction is unacceptable. Typically, the gap in a non-contact seal is between 0.1-0.3 mm. The fluid resistance of this narrow gap provides the sealing effect. However, during actual operation, if the shaft frequently switches between high and low speeds, a pressure difference will appear at both ends of the 0.1-0.3 mm gap, causing frequent changes in fluid resistance. In such cases, water can seep into the narrow gap. Accumulated leakage over time reduces the effectiveness of the non-contact seal, affecting its sealing performance. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention provides an engine shaft sealing structure that solves the problem of poor sealing and easy water leakage caused by the narrow and long gap of existing non-contact seals when dealing with frequent changes in fluid resistance.

[0004] To achieve the above objectives, the present invention provides the following technical solution: an engine shaft sealing structure, comprising: A bushing, which is fitted onto the outside of the rotating shaft; A stationary ring assembly is fixed to the inner wall of the bushing and is fitted around the outside of the rotating shaft with a first annular gap in the radial direction. The rotating ring is fixed to the outer wall of the rotating shaft. The rotating ring and the bushing are radially provided with a second annular gap. The rotating ring and the stationary ring assembly are coaxially arranged and a reserved expansion gap is provided between them. The stationary ring assembly and the moving ring are distributed along the axial direction of the rotating shaft.

[0005] In some embodiments, the stationary ring assembly includes: The first stationary ring is located on one side of the axial direction of the moving ring, and the inner wall facing the moving ring is an inner conical arc surface. The arc of the inner conical arc surface protrudes towards the moving ring, and the reserved expansion gap between it and the moving ring is the first gap. The second stationary ring is located on the other side of the axial direction of the moving ring, and the inner wall facing the moving ring is a concave arc surface. The reserved expansion gap between the concave arc surface and the moving ring is the second gap. The first gap is connected to the second annular gap and the second gap.

[0006] In some embodiments, the inner wall of the first stationary ring on the side away from the moving ring is a convex conical surface, and the conical surface of the convex conical surface is concave on the side of the moving ring.

[0007] In some embodiments, a first liquid film is provided in the first annular gap between the first stationary ring and the rotating shaft, the length of the first liquid film being longer than the length of the outer wall of the first stationary ring; a second liquid film is provided in the second annular gap between the second stationary ring and the rotating shaft, the second liquid film being narrower than the first liquid film.

[0008] In some embodiments, the moving ring is composed of a first elastic metal bowl and a second elastic metal bowl, the rims of the first elastic metal bowl and the rims of the second elastic metal bowl can contact each other, the first elastic metal bowl and the second elastic metal bowl form a metal drum, and the interior of the metal drum is a closed cavity.

[0009] In some embodiments, the rims of the first elastic metal bowl and the second elastic metal bowl may also be spaced apart, and the interior of the elastic metal drum is an open cavity.

[0010] In some embodiments, the number of stationary ring assemblies and the number of rotating rings are both several and are arranged alternately along the axis of the rotating shaft. A drainage cavity is formed between two adjacent stationary ring assemblies, and a drainage channel is provided on the side wall of the drainage cavity.

[0011] In some embodiments, the second annular gap, the first annular gap, and the reserved expansion gap form a baffle sealing channel, and the plurality of stationary ring assemblies and the plurality of rotating rings include a plurality of baffle sealing channels, and the plurality of baffle sealing channels are arranged along the axial direction of the rotating shaft to form a tortuous path seal.

[0012] In some embodiments, the first elastic metal bowl and the second elastic metal bowl are made of spring steel.

[0013] In some embodiments, the thickness of the first elastic metal bowl and the second elastic metal bowl gradually decreases from the center to the rim.

[0014] Beneficial effects The traditional narrow and long gap structure is designed as an irregular baffled gap composed of a first liquid film, a first gap, a second annular gap, a second gap, and a second liquid film. This greatly extends the length and tortuosity of the narrow and long gap, and achieves the function of shaft sealing through the dual method of narrow and long gap plus multiple baffles and pressure reduction.

[0015] When the shaft that needs to be sealed is long, multiple sets of this sealing structure can be set in the bushing, so that multiple sets of narrow and long gaps and irregular baffle gaps form a tortuous labyrinth gap. When the medium flows through the tortuous labyrinth gap, it will be throttled, depressurized and eddyed multiple times, effectively solving the sealing problem of long shafts.

[0016] The rotating ring positioned between the second stationary ring and the first stationary ring is a metal drum made of elastic metal. When the shaft rotates at a faster speed, the metal drum will extend outward under the action of centrifugal force, increasing its diameter and reducing the gap between the second rings. When the shaft rotates at a slower speed, the centrifugal force decreases, and the metal drum will contract inward. At this time, the second gap and the first gap formed between the metal drum and the second and first stationary rings on both sides will decrease. By changing the size of the gap, the shaft can adapt to different rotational speeds, thus solving the problem of reduced sealing effect of narrow and long gaps during high and low speed changes.

[0017] The metal drum made of elastic metal can also be two opposing elastic metal bowls. When the shaft rotates at a variable speed, the two opposing elastic metal bowls extend outward under the action of centrifugal force, and their diameter increases. Since the thickness gradually decreases from the center to the edge of the bowl, during the outward extension process, the two elastic metal bowls will each move closer to the second stationary ring and the first stationary ring. At this time, the first gap and the second gap will decrease, and the second annular gap between the two elastic metal bowls and the inner wall of the bushing will also decrease. When the shaft decelerates, the first gap and the second gap will increase, and the second annular gap between the two elastic metal bowls and the inner wall of the bushing will also increase. By changing the size of the gap, it can adapt to different rotational speeds of the shaft and also solve the problem of reduced sealing effect of narrow and long gaps during high and low speed changes.

[0018] An open cavity is formed between the two elastic metal cups. When multiple sets of sealing structures are axially arranged inside the bushing, the addition of the open cavity can form a more complex tortuous labyrinth gap, effectively solving the sealing problem of long rotating shafts.

[0019] When the shaft sealing structure consists of multiple sets of stationary and rotating rings arranged axially along the shaft sleeve, a drainage cavity is formed between each sealing structure. Even if the seal fails due to complex conditions, the liquid entering the shaft sleeve can be discharged in time through the drainage channel, preventing the liquid from passing through the shaft sleeve and affecting subsequent equipment. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of the present invention.

[0021] Figure 2 This is a schematic diagram of the structure of the first and second elastic metal bowls of the present invention when they are separated.

[0022] In the figure: 1. Bushing; 2. Second stationary ring; 3. First stationary ring; 4. Moving ring; 5. Second gap; 6. First gap; 7. Second annular gap; 8. First liquid film; 9. Second liquid film; 10. First elastic metal bowl; 11. Second elastic metal bowl; 12. Drainage channel; 13. Drainage cavity. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] Please see Figures 1-2 The present invention provides a technical solution: an engine shaft sealing structure, comprising: like Figure 1 As shown, bushing 1 is fitted onto the outside of the rotating shaft; stationary ring assembly is fixed to the inner wall of bushing 1, fitted onto the outside of the rotating shaft and having a first annular gap in the radial direction with the rotating shaft; rotating ring 4 is fixed to the outer wall of the rotating shaft, having a second annular gap 7 in the radial direction with bushing 1, and the rotating ring 4 and stationary ring assembly are coaxially arranged with a reserved expansion gap between them; the stationary ring assembly and the rotating ring 4 are distributed along the axial direction of the rotating shaft.

[0025] The bushing 1 is a cylindrical sleeve structure that is fitted onto the outside of the engine shaft. The bushing 1 is fixedly connected to the engine housing to ensure its positioning. The inner wall of the bushing 1 is polished to reduce the resistance to medium flow and improve the sealing performance with the rotating ring 4. The stationary ring assembly is fixed to the inner wall of the bushing 1 and assembled using an interference fit.

[0026] In some embodiments, the stationary ring assembly includes: The first stationary ring 3 is located on one side of the axial direction of the moving ring 4, and the inner wall facing the moving ring 4 is an inner conical arc surface. The arc of the inner conical arc surface protrudes towards the moving ring 4, and the reserved expansion gap between it and the moving ring 4 is the first gap 6. The second stationary ring 2 is located on the other side of the axial direction of the moving ring 4, and the inner wall of the side facing the moving ring 4 is a concave arc surface. The reserved expansion gap between the concave arc surface and the moving ring 4 is the second gap 5. The first gap 6 is connected to the second annular gap 7 and the second gap 5.

[0027] In some embodiments, the inner wall of the first stationary ring 3 on the side away from the moving ring 4 is a convex conical surface, and the conical surface of the convex conical surface is concave on the side of the moving ring 4.

[0028] In some embodiments, the first annular gap between the first stationary ring 3 and the rotating shaft is a first liquid film 8, the length of which is longer than the length of the outer wall of the first stationary ring 3; the first annular gap between the second stationary ring 2 and the rotating shaft is a second liquid film 9, the second liquid film 9 being narrower than the first liquid film 8.

[0029] By creating a stepped throttling effect through differences in gap size, fluid resistance is further increased, and media leakage is reduced.

[0030] In some embodiments, the moving ring 4 is composed of a first elastic metal bowl 10 and a second elastic metal bowl 11. The rims of the first elastic metal bowl 10 and the second elastic metal bowl 11 can contact each other. The first elastic metal bowl 10 and the second elastic metal bowl 11 form a metal drum, and the inside of the metal drum is a closed cavity.

[0031] like Figure 2 As shown, in some embodiments, the rim of the first elastic metal bowl 10 and the rim of the second elastic metal bowl 11 may also be spaced apart, and the interior of the elastic metal drum is an open cavity.

[0032] In some embodiments, the number of stationary ring assemblies and rotating rings 4 are both several and are arranged alternately along the axis of rotation. A drainage cavity 13 is formed between two adjacent stationary ring assemblies, and a drainage channel 12 is provided on the side wall of the drainage cavity 13.

[0033] In actual assembly, the bushing 1 is first installed on the outside of the engine shaft. Then, the stationary ring components are fixed to the inner wall of the bushing 1 using a heat-fitting process. Subsequently, the rotating ring 4 is fixed to the corresponding position on the shaft. Finally, the drain channel 12 and the guide pipe are assembled to complete the overall assembly. After assembly, when the engine shaft rotates at high speed, the rotating ring 4 rotates synchronously with the shaft, forming a multi-stage tortuous path seal and baffle seal with the stationary ring components, effectively intercepting lubricating oil and impurities. When the shaft is displaced due to thermal expansion, the elastic metal cup structure of the rotating ring 4 can adaptively deform to compensate for the gap change and avoid seal failure. At the same time, the drain structure promptly discharges the trapped liquid, ensuring the long-term stable operation of the sealing structure.

[0034] In some embodiments, the second annular gap 7, the first annular gap, and the reserved expansion gap form a baffle sealing channel, and a plurality of stationary ring assemblies and a plurality of rotating rings 4 include a plurality of baffle sealing channels, which are arranged along the axial direction of the rotating shaft to form a tortuous path seal.

[0035] In some embodiments, the first elastic metal bowl 10 and the second elastic metal bowl 11 are made of spring steel that has undergone quenching and medium-temperature tempering treatment.

[0036] In some embodiments, the thickness of the first elastic metal bowl 10 and the second elastic metal bowl 11 gradually decreases from the center to the rim.

[0037] The spring steel is 65Mn spring steel, and its hardness reaches HRC42-48 after heat treatment. It has excellent elasticity and fatigue resistance, ensuring elastic expansion during high-speed rotation and complete springback after stopping.

[0038] The thickness of the first elastic metal bowl 10 and the second elastic metal bowl 11 ranges from 0.8 to 2.5 mm, with the center being the thickest and the edge being the thinnest, so that the moving ring 4 can expand uniformly under centrifugal force and the expansion amount is controllable (0.1-0.8 mm).

[0039] Example 1: Single-unit baffle seal + closed elastic metal drum structure: The bushing 1 is fitted onto the outside of the engine shaft and is fixed to the engine housing by bolts to ensure the static positioning of the bushing 1. The inner wall of the bushing 1 is polished (Ra≤0.8μm) to reduce the resistance to medium flow and improve the sealing performance with the rotating ring 4. At this time, the first gap 6 is connected to the second annular gap 7 and the second gap 5, forming a complete baffle sealing channel. When the engine shaft rotates at low speed, the centrifugal force on the rotating ring 4 is small, and the metal drum is in a contracted state. At this time, the first gap 6, the second gap 5 and the second annular gap 7 maintain a preset position. The size relies on the dual throttling effect of the first liquid film 8 and the baffle sealing channel to achieve sealing. When the shaft rotates at high speed, the centrifugal force increases, and the elastic metal drum extends outward, increasing its diameter. This makes the second annular gap 7 smaller. At the same time, the two sides of the metal drum approach the first stationary ring 3 and the second stationary ring 2 respectively, and the first gap 6 and the second gap 5 decrease simultaneously, increasing fluid resistance. When the shaft decelerates, the centrifugal force decreases, the metal drum elastically rebounds, and each gap returns to the preset size, thus adapting to the frequent high and low speed switching of the shaft and avoiding water leakage caused by pressure difference fluctuations at both ends of the gap.

[0040] Example 2: A sealed + open elastic metal drum structure with multiple tortuous paths: This embodiment provides an engine shaft sealing structure, which is mainly adapted to long shafts and high-speed engine shafts, focusing on solving the sealing problem of longer shafts, while improving sealing redundancy.

[0041] The bushing 1 contains several sets of stationary ring assemblies and several sets of rotating rings 4. The sets of stationary ring assemblies and rotating rings 4 are arranged alternately along the axial direction of the rotating shaft. A drainage channel 12 is provided on the side wall of the bushing 1 at the position of two adjacent sets of stationary ring assemblies. The drainage channel 12 is connected to the liquid collection structure outside the bushing 1 to drain a small amount of liquid that has seeped in. Each set of stationary ring assemblies is fixed to the inner wall of the bushing 1. The stationary ring assembly is fitted onto the outside of the rotating shaft and has a first annular gap in the radial direction with the rotating shaft. The stationary ring assembly includes a first stationary ring 3 and a second stationary ring 2. The first stationary ring 3 is located on the left side of the rotating ring 4, on the inner wall of the side closer to the rotating ring 4. The first stationary ring 3 has an inner conical arc-shaped surface, forming a first gap 6 with the moving ring 4; the second stationary ring 2 is located on the right side of the moving ring 4, and its inner wall near the moving ring 4 is an inner concave arc-shaped surface, forming a second gap 5 with the moving ring 4; the inner wall of the first stationary ring 3 away from the moving ring 4 is an outer convex conical surface, the length of the first liquid film 8 between the first stationary ring 3 and the rotating shaft is longer than the length of the outer wall of the first stationary ring 3, and the second liquid film 9 between the second stationary ring 2 and the rotating shaft is narrower than the first liquid film 8. The first gap 6, the second annular gap 7, the second gap 5 are connected to the first liquid film 8 and the second liquid film 9, forming a single set of baffle sealing channels. Each set of rotating rings 4 is fixed to the outer wall of the rotating shaft using a double fixing method of interference fit and key connection to ensure that the rotating rings 4 rotate synchronously with the rotating shaft. A second annular gap 7 is radially provided between the rotating rings 4 and the bushing 1. The rotating rings 4 consist of a first elastic metal cup 10 and a second elastic metal cup 11. The rims of the first elastic metal cup 10 and the second elastic metal cup 11 are spaced apart (0.5-1mm). The interior of the elastic metal cups is an open cavity, which communicates with the gaps between two adjacent sets of sealing structures, further increasing the tortuosity of the sealing channel. When the engine rotating shaft rotates, each set of rotating rings 4 rotates synchronously with the rotating shaft. Under centrifugal force, the first elastic metal bowl 10 and the second elastic metal bowl 11 extend outward, increasing their diameter, while the first gap 6, the second gap 5, and the second annular gap 7 decrease, meeting the requirements of high-speed sealing. When the shaft decelerates, the rotating ring 4 elastically rebounds, and all gaps recover, avoiding water leakage caused by pressure difference fluctuations. For longer shafts, the tortuous path sealing composed of multiple sets of baffle sealing channels, combined with the guiding effect of the open cavity, significantly improves fluid resistance. Even if a small amount of medium seeps in, it will enter the drain cavity 13 and be discharged in time through the drain channel 12, preventing the medium from passing through the bushing 1 and affecting subsequent equipment, thus improving sealing reliability.

[0042] Example 3: Precision sealing + corrosion-resistant elastic metal drum structure: This embodiment provides an engine shaft sealing structure, mainly suitable for engine shafts in high-temperature and corrosive media environments (such as marine engines and chemical industry engines). It emphasizes corrosion resistance and high-precision sealing. A bushing 1 is fitted onto the outside of the engine shaft. The bushing 1 is made of corrosion-resistant stainless steel (316L), with its inner wall precision polished (Ra≤0.4μm) to reduce media adhesion and improve the fit accuracy with the rotating ring 4. The bushing 1 is connected to the engine housing via a flange, with a sealing gasket at the connection to prevent media leakage between the bushing 1 and the housing. In high-temperature and corrosive media environments, the rotating ring 4, made of 17-7PH elastic stainless steel, possesses excellent corrosion resistance and high-temperature resistance while maintaining excellent elastic rebound. The stationary ring assembly is fixed to the inner wall of the bushing 1 using a double-layer adhesive and bolt fixing method. This method ensures the reliability of the stationary ring assembly in corrosive environments. The stationary ring assembly is fitted around the outside of the rotating shaft and has a first annular gap radially between it and the shaft. The stationary ring assembly includes a first stationary ring 3 and a second stationary ring 2. Both the first stationary ring 3 and the second stationary ring 2 are made of corrosion-resistant ceramic material (silicon nitride), which has excellent corrosion resistance and high temperature resistance. The first stationary ring 3 is located on the left side of the rotating ring 4, and the inner wall of the side closer to the rotating ring 4 is an inner conical arc surface, forming a first gap 6 between it and the rotating ring 4. The second stationary ring 2 is located on the right side of the rotating ring 4, and the inner wall of the side closer to the rotating ring 4 is an inner concave arc surface, forming a second gap 5 between it and the rotating ring 4. The inner wall of the first stationary ring 3 on the side away from the rotating ring 4 is an outer convex conical surface. The length of the first liquid film 8 is longer than the length of the outer wall of the first stationary ring 3, and the length of the second liquid film 9 is narrower than the length of the first liquid film 8, forming a stepped throttling structure.

[0043] The moving ring 4 is fixed to the outer wall of the rotating shaft and connected by a corrosion-resistant alloy key. The moving ring 4 and the bushing 1 are radially provided with a second annular gap 7. The moving ring 4 is composed of a first elastic metal cup 10 and a second elastic metal cup 11. The cup edges of the first elastic metal cup 10 and the second elastic metal cup 11 are fixed together by laser welding to form a metal drum with a closed cavity inside. The first elastic metal cup 10 and the second elastic metal cup 11 are made of 17-7PH elastic stainless steel. After solution treatment and aging treatment, they have excellent corrosion resistance, high temperature resistance (≤300℃) and elastic resilience, making them suitable for corrosive media environments.

[0044] The thickness of the first elastic metal bowl 10 and the second elastic metal bowl 11 gradually decreases from the center to the edge, with a thickness range of 0.5-2.0 mm, a center thickness of 1.8-2.0 mm, and an edge thickness of 0.5-0.8 mm. This ensures that the moving ring 4 can expand uniformly when rotating at high speed (≤12000 r / min), with the expansion amount controlled within 0.05-0.5 mm, to meet precision sealing requirements. The outer wall of the moving ring 4 is nitrided to improve surface hardness and wear resistance, extending its service life. The second annular gap 7, the first annular gap, and the reserved expansion gap form a baffle sealing channel. The inner wall of the baffle sealing channel is smoothed to reduce the resistance to medium flow and prevent medium accumulation in the gap. The inner wall of the bushing 1 has an annular groove corresponding to the position of the second annular gap 7 to collect a small amount of infiltrated medium. The annular groove is connected to the drainage channel 12 on the side wall of the bushing 1 to achieve timely discharge of the medium.

[0045] When the shaft rotates, the moving ring 4 expands elastically under centrifugal force, adjusting the gap dimensions to adapt to high and low speed switching and avoid water leakage caused by pressure difference fluctuations; the stationary ring assembly made of silicon nitride can resist the erosion of corrosive media and extend the service life of the sealing assembly; the stepped throttling effect of the baffle sealing channel, combined with the drainage function of the drainage channel 12, achieves a high-precision and corrosion-resistant sealing effect, adapting to the sealing requirements of engine shafts in special environments.

[0046] Example 4: This example provides an engine shaft sealing structure, which is mainly suitable for engine shafts with variable load, high pressure difference, and long service life (such as heavy truck, aircraft engine, and high pressure fuel pump shaft). The core solution is to address the dual problems of large pressure difference fluctuations and bidirectional medium leakage (internal / external leakage) during high-speed and low-speed transitions.

[0047] The bushing 1 is fitted onto the outside of the engine shaft, and both ends of the shaft are connected to the engine housing via floating flanges, which can accommodate the slight thermal expansion and deformation of the shaft. The multi-stage stationary ring assembly is fixed to the inner wall of the bushing 1 and is arranged at equal intervals along the shaft axis. The core structure is formed by integral stamping of the left and right elastic metal cups, and the whole is a two-way open cavity structure. The cavity is filled with high-temperature damping oil (silicone oil, viscosity grade 1000cSt). Multi-stage sealing channels: multiple sets of multi-stage stationary ring assemblies and multiple sets of dynamic rings cooperate to form multiple single-stage baffle sealing channels arranged along the shaft axis, which are superimposed to form a tortuous path sealing channel. Adjacent channels are connected through the drainage cavity 13 of the pressure difference compensation guide assembly, which further extends the fluid flow path and realizes multi-stage throttling, pressure reduction and eddy current.

[0048] Low-speed operation: The engine shaft rotates at low speed, the centrifugal force is small, the left and right elastic metal cups are in a contracted state, the first gap 6, the second gap 5, and the second annular gap 7 maintain the preset initial size (0.2-0.3mm), and the single-stage baffle sealing channel relies on the fluid resistance of the narrow and long gap to achieve basic sealing; Speed-up condition: As the shaft speed increases, the centrifugal force increases. Under the synergistic effect of centrifugal force and the middle elastic connecting ring, the left and right elastic metal bowls expand outward uniformly, increasing in diameter by 0.1-0.4mm. The first gap 6 and the second gap 5 decrease simultaneously, and the second annular gap 7 also shrinks accordingly. By adaptively reducing the gaps, the fluid resistance is increased, offsetting the pressure difference fluctuations at high speed. Deceleration condition: The shaft speed decreases, the centrifugal force decreases, and the left and right elastic metal cups contract under the elastic rebound. The first gap 6, the second gap 5, and the second annular gap 7 return to their initial size, avoiding medium leakage caused by excessive gaps at low speeds. Differential pressure compensation and leak prevention: The multi-stage tortuous sealing channel achieves multi-stage throttling and pressure reduction for leaking fluid. Even if a small amount of fluid passes through the first-stage channel, it will enter the adjacent drain cavity 13, avoiding seal failure caused by liquid accumulation. Long shaft adaptation: The labyrinth structure formed by the superposition of multi-level sealing channels can effectively adapt to the sealing requirements of long shafts, avoid the decrease in sealing effect caused by excessive shaft length, block external impurities, protect the sealing components from corrosion, and extend the overall lifespan.

[0049] It should be noted that, in this document, 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, the phrase "comprising an element defined as..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes the element.

[0050] It is worth noting that all standard parts used in this invention can be purchased from the market, and irregularly shaped parts can be customized according to the description and drawings. The specific connection methods of each part all adopt conventional methods such as bolts, rivets, and welding that are mature in the prior art. The models of electrical structure equipment involved can be selected according to the user's needs, as long as they meet the requirements of this application. In addition, the circuit connection adopts conventional connection methods in the prior art. The supporting electrical structures such as the control, current detection, position feedback, predicted voltage synchronization and parameter adjustment of the electrical equipment are all existing technologies, such as PLC controllers and module structures, so they will not be described in detail here.

[0051] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An engine shaft sealing structure, characterized in that, include: A bushing (1) is fitted onto the outside of the rotating shaft; A stationary ring assembly is fixed to the inner wall of the bushing (1), and the stationary ring assembly is sleeved on the outside of the rotating shaft and has a first annular gap radially between it and the rotating shaft. The moving ring (4) is fixed to the outer wall of the rotating shaft. The moving ring (4) and the bushing (1) are provided with a second annular gap (7) in the radial direction. The moving ring (4) and the stationary ring assembly are coaxially arranged and a reserved expansion gap is provided between them. The stationary ring assembly and the moving ring (4) are distributed along the axial direction of the rotating shaft.

2. The engine shaft sealing structure according to claim 1, characterized in that, The stationary ring assembly includes: The first stationary ring (3) is located on one side of the axial direction of the moving ring (4), and the inner wall facing the moving ring (4) is an inner conical arc surface. The arc of the inner conical arc surface protrudes towards the moving ring (4), and the reserved expansion gap between it and the moving ring (4) is the first gap (6). The second stationary ring (2) is located on the other side of the axial direction of the moving ring (4), and the inner wall facing the moving ring (4) is a concave arc surface. The reserved expansion gap between the concave arc surface and the moving ring (4) is the second gap (5). The first gap (6) is connected to the second annular gap (7) and the second gap (5).

3. The engine shaft sealing structure according to claim 2, characterized in that, The inner wall of the first stationary ring (3) on the side away from the moving ring (4) is a convex conical surface, and the conical surface of the convex conical surface is concave on the side of the moving ring (4).

4. The engine shaft sealing structure according to claim 2, characterized in that, A first liquid film (8) is provided in the first annular gap between the first stationary ring (3) and the rotating shaft, and the length of the first liquid film (8) is longer than the length of the outer wall of the first stationary ring (3); a second liquid film (9) is provided in the second annular gap (7) between the second stationary ring (2) and the rotating shaft, and the second liquid film (9) is narrower than the first liquid film (8).

5. The engine shaft sealing structure according to claim 1, characterized in that, The moving ring (4) is composed of a first elastic metal bowl (10) and a second elastic metal bowl (11). The rims of the first elastic metal bowl (10) and the rims of the second elastic metal bowl (11) can contact each other. The first elastic metal bowl (10) and the second elastic metal bowl (11) form a metal drum. The inside of the metal drum is a closed cavity.

6. The engine shaft sealing structure according to claim 5, characterized in that, The rims of the first elastic metal bowl (10) and the second elastic metal bowl (11) may also be spaced apart, and the interior of the elastic metal drum is an open cavity.

7. The engine shaft sealing structure according to claim 5, characterized in that, The thickness of the first elastic metal bowl (10) and the second elastic metal bowl (11) gradually decreases from the center to the edge of the bowl.

8. The engine shaft sealing structure according to claim 1, characterized in that, The number of stationary ring assemblies and the number of rotating rings (4) are both several and they are arranged alternately along the axis of the rotating shaft. A drainage cavity (13) is formed between two adjacent stationary ring assemblies, and a drainage channel (12) is provided on the side wall of the drainage cavity (13).

9. The engine shaft sealing structure according to claim 8, characterized in that, The second annular gap (7), the first annular gap and the reserved expansion gap form a baffle sealing channel. The several static ring assemblies and the several dynamic rings (4) contain several baffle sealing channels. The several baffle sealing channels are arranged along the axial direction of the rotating shaft to form a tortuous path seal.

10. The engine shaft sealing structure according to claim 5, characterized in that, The first elastic metal bowl (10) and the second elastic metal bowl (11) are made of spring steel.

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