Stepped tooth brush type combined sealing device with inclined arc groove

Abstract

The invention provides a stepped tooth brush type combined sealing device with an inclined arc groove, comprising: a runway which is of a revolving body structure, the outer wall of the runway is provided with a plurality of step structures, and the distance between the upper end face of each step structure and the revolving axis of the runway is increased in a stepped manner along the gas flowing direction; and the sealing tooth is arranged on the outer side of the runway in a sleeving mode, a plurality of cavities are formed in the inner side of the sealing tooth, and the multiple cavities and the multiple step structures are arranged in a one-to-one correspondence mode and form multiple sealing units of the same structure. The machining difficulty is effectively reduced by simplifying the shapes of the sealing teeth, and meanwhile, the number of leakage points is reduced and the assembly process is optimized by utilizing the layout of the stepped sealing teeth, so that the sealing device is more flexible to use. The design of the wide sealing teeth and the small groove depth ratio greatly improves the aeroelastic stability of the sealing teeth, and the structural safety is guaranteed. Due to the design of the inclined arc grooves, the airflow flowing path is optimized, the dissipation effect is enhanced, and the sealing effect of the stepped teeth is obviously improved.

Description

Technical Field

[0001] This invention relates to the field of aero-engine testing technology, and specifically to a stepped toothed brush-type combined sealing device with an inclined circular arc groove. Background Technology

[0002] In certain aero-engine testing operations, a high-pressure sealing environment is typically provided for the engine bearing cavity sealing device using a sealed cavity. This sealed cavity usually has multiple sealing positions, which are limited by factors such as the structural dimensions of the test piece, axial spacing, sealing surface linear velocity, and assembly interference, making contact-type mechanical seals unsuitable. Non-contact sealing methods primarily use grate seals, but traditional grate seals suffer from high leakage rates, demanding machining requirements for the sealing teeth, and potential aeroelastic instability, hindering further improvements in grate seal performance. Interlaced grate structures require dividing the sealing teeth into multiple sector segments for installation, introducing unnecessary leakage points that reduce sealing performance, and resulting in complex structures, high machining precision requirements, and cumbersome assembly. Summary of the Invention

[0003] In view of this, the present invention provides a stepped toothed brush type combined sealing device with inclined arc groove to solve the problems of large leakage, complex processing technology and high risk of aeroelastic instability of traditional toothed seals.

[0004] The present invention provides the following technical solution: a stepped toothed brush type combined sealing device with inclined arc groove, comprising: a runway, which has a rotating structure, and the outer wall of the runway is provided with multiple stepped structures, and the distance between the upper end face of the stepped structure and the rotation axis of the runway increases stepwise along the gas flow direction; sealing teeth, which are sleeved on the outer side of the runway, and the inner side of the sealing teeth is provided with multiple cavities, and the multiple cavities are provided one-to-one with the multiple stepped structures to form multiple sealing units with the same structure.

[0005] Compared with existing technologies, the beneficial effects achieved by at least one of the above-mentioned technical solutions of the present invention include at least the following: The wide stepped tooth-brush combined sealing device with inclined arc groove provided by the present invention effectively reduces the processing difficulty by simplifying the shape of the sealing teeth. Simultaneously, the stepped sealing tooth layout reduces the number of leakage points, optimizes the assembly process, and makes the sealing device more flexible in use. The wide sealing teeth and small groove depth ratio design greatly improves the aeroelastic stability of the sealing teeth, ensuring structural safety. The inclined arc groove design optimizes the airflow path, enhances dissipation, and significantly improves the sealing effect of the stepped teeth.

[0006] Compared to conventional toothed structures, leakage can be reduced by approximately 20%. When used in conjunction with a single-stage brush seal, it forms a wide stepped tooth-brush combined seal structure with inclined arc grooves, further optimizing the sealing pressure differential. Within the sealing pressure differential range of 28 kPa to 500 kPa, the pressure differential between the stepped tooth and brush seals is reduced by approximately 50%, further controlling leakage. Attached Figure Description

[0007] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0008] Figure 1 This is a cross-sectional structural diagram of an embodiment of the present invention; Figure 2 This is a cross-sectional enlarged schematic diagram of a wide stepped tooth with an inclined arc groove provided in an embodiment of the present invention; Figure 3 This is a cross-sectional schematic diagram of the sealing tooth structure in the combined sealing device provided in the embodiment of the present invention; Figure 4 This is a cross-sectional schematic diagram of the inclined arc groove stepped tooth structure on the runway in the combined sealing device provided in the embodiment of the present invention.

[0009] The attached diagram is labeled as follows: 1. Outer ring; 11. Intake passage; 12. Arc-shaped cavity; 13. Trapezoidal cavity; 2. Elastic retaining ring; 3. Brush seal assembly; 4. Stop pin; 5. Sealing teeth; 6. Runway. Detailed Implementation

[0010] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0011] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0012] like Figures 1 to 4 As shown, this embodiment of the invention provides a stepped toothed brush type combined sealing device with inclined arc grooves. The core is used for sealing the airflow path of aero-engines. Its overall structure is symmetrical and mainly consists of runway 6 and sealing teeth 5. The two work together to form a multi-stage sealing unit to achieve a high-efficiency sealing effect.

[0013] Runway 6 is a rotating structure, coaxially mounted on the engine main shaft. Its outer wall is machined with multiple continuously arranged stepped structures. Along the gas flow direction (i.e. from the intake end to the exhaust end), the distance between the upper end face of each stepped structure and the rotation axis of runway 6 increases in a step-like manner, and the distance increment between adjacent steps is consistent. The sealing tooth 5 is a ring structure, coaxially sleeved on the outside of the runway 6. Its inner sidewall is machined with multiple cavities that match the shape of the stepped structure of the runway 6. Each cavity and the corresponding stepped structure enclose a sealing unit. All sealing units have the same structure and are arranged in series along the gas flow direction. The output end of the previous sealing unit is connected to the input end of the next sealing unit to form a continuous sealing flow channel.

[0014] Runway 6, as a rotating mating component of the sealing device, is made of high-strength alloy steel (such as 40CrNiMoA). This material possesses excellent wear resistance and structural strength, and can adapt to the high-speed rotation conditions of aero-engines. The rotating structure of runway 6 is precision machined, and the number of stepped structures on its outer wall can be adjusted according to actual sealing requirements. Preferably, 3-5 steps are provided, and in this embodiment, 4 stepped structures are preferred, forming a 4-level sealing unit.

[0015] Along the gas flow direction, the distance between the upper surface of each stepped structure and the axis of rotation of runway 6 increases by the same increment δ, ensuring that the radial fit clearance of each sealing unit is uniform. In this embodiment, the increment δ is preferably 0.4mm, which ensures the effect of stepped sealing while avoiding the problem of sudden airflow changes caused by excessive increment.

[0016] The sealing tooth 5 is a single-ring structure made of aluminum alloy (such as 6061 aluminum alloy), whose material hardness is lower than that of the runway 6. The advantages of this design are: when the sealing tooth 5 and the runway 6 have slight contact and friction, the sealing tooth 5 will wear out first, which can effectively protect the runway 6 from damage and reduce subsequent maintenance costs; at the same time, the aluminum alloy is lightweight, which can reduce the overall weight of the sealing device and is less likely to generate sparks, thus improving safety in use.

[0017] The sealing teeth 5 are precision milled, and their inner cavities correspond one-to-one with the stepped structure of the runway 6. The shape of the cavities is adapted to the stepped structure and the flow channel shape of the sealing unit. A radial clearance fit is used between the sealing teeth 5 and the runway 6, with a preferred clearance of 0.2mm. This clearance size ensures sealing performance while avoiding interference under high-speed rotation conditions. The outer side of the sealing teeth 5 is fixed to the stationary housing of the engine via an outer ring. The mating surface between the outer ring and the sealing teeth 5 features a tapered hole design and is coated with sealant to further enhance fixing reliability and sealing performance.

[0018] Each sealing unit consists of an air intake channel 11, an arc-shaped cavity 12, and a trapezoidal cavity 13, which are integrally formed to create a continuous airflow channel. The specific structure is as follows: One end of the air intake channel 11 is connected to the air intake end (or the trapezoidal cavity 13 of the previous sealing unit), and the other end is connected to the arc-shaped cavity 12 and the trapezoidal cavity 13. Its function is to guide the airflow into the interior of the sealing unit. The air intake channel 11 is arranged axially, with a length of L1, a rectangular cross-section, and a height of a (i.e., the radial dimension of the air intake channel 11). In this embodiment, L1 is preferably 2 mm, and a is preferably 0.2 mm. This size design ensures that the airflow smoothly enters the subsequent cavities and avoids airflow congestion.

[0019] One end of the arc-shaped cavity 12 is smoothly connected to the outlet end of the intake channel 11, and the other end is positioned horizontally higher than the end connected to the intake channel 11, forming an inclined structure. The cross-section of the arc-shaped cavity 12 is circular, and the radius R of the circular arc is preferably 0.5 mm. The circular arc transition can reduce airflow resistance.

[0020] The angle between the tangent at the other end of the trapezoidal cavity 12 and the rotation axis of the runway 6 is β, and satisfies α+β=90° (α is the angle between the side of the trapezoidal cavity 13 and the vertical direction). In this embodiment, α is preferably 7°, so β=83°. This angle design allows the airflow to form a vortex within the arc-shaped cavity 12, enhancing the dissipation of airflow energy and improving sealing performance.

[0021] In addition, the distance between the endpoint of the other end of the arc-shaped cavity 12 and the center of the arc-shaped cavity 12 is L3, and L3=δ. In this embodiment, L3=0.8mm. This size design can ensure that the position of the arc-shaped cavity 12 is accurately matched with the stepped structure, and optimize the airflow path.

[0022] The trapezoidal cavity 13 is located above the arc-shaped cavity 12 and is connected to both the air intake channel 11 and the arc-shaped cavity 12. Its shape is an isosceles trapezoid, and it is a core energy-dissipating structure of the sealing unit. The angle between the side of the trapezoidal cavity 13 and the vertical direction is α, and the value of α ranges from 5° ≤ α ≤ 10°. In this embodiment, α is preferably 7°. This angle allows the airflow to generate a secondary vortex within the trapezoidal cavity, further dissipating airflow energy.

[0023] The length of the trapezoidal cavity 13 along the axial direction is L2, and it satisfies 2L1≤L2≤3L1. In this embodiment, L1=2mm, so L2 is preferably 5mm (i.e. 2.5*L1). This size ratio can ensure energy dissipation while avoiding excessive axial size of the sealing unit, thus adapting to the compact space requirements of aero-engines.

[0024] Along the gas flow direction, the sealing units are connected in series: the outlet end of the trapezoidal cavity 13 of the previous sealing unit is smoothly connected to the inlet end of the air inlet channel 11 of the next sealing unit, forming a continuous multi-stage sealing flow channel. After the airflow enters the air inlet channel 11 of the first-stage sealing unit from the inlet end, it flows through the arc-shaped cavity 12 and the trapezoidal cavity 13 in sequence, completing the first energy dissipation and pressure reduction; then the airflow enters the air inlet channel 11 of the second-stage sealing unit, repeating the above energy dissipation process. Through the synergistic effect of the multi-stage sealing units, a significant sealing effect is finally achieved.

[0025] It should be noted that the selection of each key parameter in this embodiment is based on a comprehensive consideration of sealing effect, processing technology, and adaptability to operating conditions, as detailed below: Angular relationship α+β=90°: This design allows the tilt direction of the arc-shaped cavity 12 to complement the side direction of the trapezoidal cavity 13, ensuring a smooth transition of airflow within the flow channel and avoiding increased leakage caused by sudden changes in airflow. Dimensional relationship δ≥2a: In this embodiment, δ=0.4mm and a=0.2mm, satisfying δ=2a, which not only ensures the step height of the stepped structure, but also avoids the increased processing difficulty of the sealing tooth 5 due to excessive δ; Size relationship 2L1≤L2≤3L1: This range can balance the energy dissipation effect and axial dimension of the sealing unit. If L2 is too small, the eddy current will not be formed sufficiently and the energy dissipation effect will be poor. If L2 is too large, the axial dimension of the sealing device will be too long and it will not be able to adapt to the compact installation space.

[0026] The assembly process of the sealing device described in this invention is simple, and the specific steps are as follows: First, the stop pin 4 is placed into the outer ring 1, and then the brush seal assembly 3 is installed into the outer ring 1, ensuring that the stop pin 4 accurately enters the pre-drilled pin hole on the brush seal assembly 3. Then, the elastic retaining ring 2 is installed into the pre-drilled annular groove on the outer ring 1. In some embodiments, sealant can be applied to the outer cylindrical surface and the side facing the stop pin 4 of the brush seal assembly 3 during assembly to enhance the sealing effect. Typically, the sealing teeth 5 are not disassembled after being machined together with the outer ring 1.

[0027] Runway 6 is fixed to the engine main shaft by interference fit, ensuring that the stepped structure of runway 6 is arranged along the gas flow direction, and the coaxiality error between runway 6 and main shaft does not exceed 0.02mm. The sealing tooth 5 is fitted onto the outside of the runway 6. The position of the sealing tooth 5 is adjusted so that the inner cavity corresponds precisely to the stepped structure of the runway 6, ensuring the integrity of the flow channel shape of each sealing unit. Install the runway 6 with the sealing teeth 5 fitted on and the main shaft assembly into the preset position on the engine housing. Fix the sealing teeth 5 to the stationary housing through the outer ring. Apply sealant to the mating surface between the outer ring and the sealing teeth 5 to enhance the sealing performance. After assembly, check the radial clearance between sealing tooth 5 and runway 6 to ensure that the clearance is about 0.2mm and there is no interference.

[0028] The sealing effect of the sealing device described in this invention is mainly achieved through the airflow energy consumption of the multi-stage sealing unit. The specific working process is as follows: After the high-pressure gas enters the sealing device from the inlet end, it first enters the inlet channel 11 of the first-stage sealing unit. Under the guidance of the inlet channel 11, the airflow smoothly enters the arc-shaped cavity 12. Because the arc-shaped cavity 12 has an inclined arc-shaped structure, the airflow will form a vortex in the cavity, and the kinetic energy of the airflow will be converted into heat energy, achieving the first energy dissipation and the initial pressure reduction. The airflow passing through the arc-shaped cavity 12 enters the trapezoidal cavity 13. The isosceles trapezoidal structure allows the airflow to diffuse further, forming a secondary vortex, which dissipates energy again and further reduces the pressure. The airflow passing through the first-stage sealing unit enters the air intake channel 11 of the second-stage sealing unit, repeating the above-mentioned vortex energy consumption process. Through the synergistic effect of the four-stage sealing units, the pressure and velocity of the airflow are greatly reduced, and the leakage amount when it is finally discharged from the outlet end is significantly reduced.

[0029] In addition, the stepped mating structure of the sealing teeth 5 and the runway 6 can effectively divide the airflow channel, avoid the formation of a continuous high-speed airflow channel, and further suppress leakage; at the same time, the structural design of the wide sealing teeth optimizes the aeroelastic stability and avoids the aeroelastic instability problem that is prone to occur in traditional tooth seals.

[0030] The stepped toothed brush-type combined sealing device with inclined arc grooves provided in this embodiment has been experimentally verified to reduce leakage by approximately 20% compared to traditional comb-tooth sealing structures. Within a sealing pressure differential range of 28 kPa to 500 kPa, the synergistic effect of the stepped teeth and multi-stage sealing units can reduce the pressure differential by approximately 50%, significantly improving the sealing effect. Furthermore, both the sealing teeth 5 and the runway 6 of this device are integral ring structures with no additional leakage points, simplifying the manufacturing process and improving assembly convenience. It can be widely applied to airflow path sealing scenarios in aero-engines.

[0031] Modified embodiments The number of steps can be adjusted to 3 or 5, and the number of sealing units can be adjusted accordingly, as long as the synergistic effect of multi-level sealing is ensured; Key parameters can be adjusted within the range defined in the claims. For example, α can be selected as 5°, 8° or 10°, and β can be adjusted to 85°, 82° or 80° accordingly; L1 can be selected as 1.8 mm, L2 can be selected as 4 mm (2.22L1) or 5.4 mm (3L1); δ can be selected as 1.0 mm, and a can be selected as 0.4 mm, satisfying δ≥2a; The material for sealing tooth 5 can be other materials with a lower hardness than that for track 6 (such as copper alloy), and the material for track 6 can be other high-strength wear-resistant materials according to the actual working conditions, as long as the hardness matching requirements are met.

[0032] The above description is merely a specific embodiment of the present invention and should not be construed as limiting the scope of the invention. Therefore, any substitution of equivalent components or equivalent changes and modifications made within the scope of protection of this patent should still fall within the scope of this patent. Furthermore, the technical features, technical features and technical solutions, and technical solutions in this invention can be freely combined and used.

Claims

1. A stepped toothed brush-type combined sealing device with an inclined arc groove, characterized in that, include: The runway (6) has a rotating body structure. The outer wall of the runway (6) is provided with multiple stepped structures, and the distance between the upper end of the stepped structure and the rotation axis of the runway (6) increases stepwise along the gas flow direction. The sealing tooth (5) is fitted on the outside of the runway (6). The inner side of the sealing tooth (5) is provided with multiple cavities, and the multiple cavities are provided in correspondence with multiple stepped structures to form multiple sealing units with the same structure.

2. The stepped toothed brush type combined sealing device with inclined arc groove according to claim 1, characterized in that, The sealing unit includes: The air intake passage (11) is connected to the air intake end; The arc-shaped cavity (12) is connected at one end to the outlet end of the air intake channel (11), and the other end of the arc-shaped cavity (12) is positioned higher than one end of the arc-shaped cavity (12) in the horizontal direction. The trapezoidal cavity (13) is connected to both the air intake channel (11) and the arc-shaped cavity (12), and the trapezoidal cavity (13) is located above the arc-shaped cavity (12).

3. The stepped toothed brush type combined sealing device with inclined arc groove according to claim 2, characterized in that, The trapezoidal cavity (13) of the front sealing unit is connected to the air intake passage (11) of the rear sealing unit.

4. The stepped toothed brush type combined sealing device with inclined arc groove according to claim 2, characterized in that, Along the axial direction, the length of the air intake channel (11) is L1, and the length of the sealing unit is L2, where 2*L1≤L2≤3*L1.

5. The stepped toothed brush type combined sealing device with inclined arc groove according to claim 2, characterized in that, The trapezoidal cavity (13) is an isosceles trapezoidal cavity, and the angle between the side of the trapezoidal cavity (13) and the vertical direction is α, where 5°≤α≤10°.

6. The stepped toothed brush type combined sealing device with inclined arc groove according to claim 5, characterized in that, The other end of the arc-shaped cavity (12) is inclined toward the air intake channel (11), and the angle between the tangent of the other end of the arc-shaped cavity (12) and the rotation axis of the runway (6) is β, where α+β=90°.

7. The stepped toothed brush type combined sealing device with inclined arc groove according to claim 6, characterized in that, The height difference between the bottom surface of the trapezoidal cavity (13) of the rear sealing unit and the bottom surface of the trapezoidal cavity (13) of the front sealing unit is δ, and the height of the air intake channel (11) is a, where δ≥2a.

8. The stepped toothed brush type combined sealing device with inclined arc groove according to claim 7, characterized in that, The distance between the endpoint of the other end of the arc-shaped cavity (12) and the center of the arc-shaped cavity (12) is L3, where L3 = δ.

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