A double-end air-film supported follow-up air-film end cylindrical sealing structure

Abstract

This invention discloses a double-end-face air-film supported follow-up air-film end-cylindrical sealing structure, including a sealing cavity, a floating ring mounting seat fixedly connected to one end of the sealing cavity, and a rotor eccentrically passing through the sealing cavity. A first sealing cavity is provided between the floating ring mounting seat and the sealing cavity. A graphite floating ring, a floating ring seat, and a second grate seal are installed sequentially from top to bottom in the first sealing cavity. There is a first floating sealing gap radially between the rotor and the graphite floating ring, and a second floating sealing gap axially between the first sealing end face and the floating ring seat. A pump-out dynamic pressure groove is formed on the first sealing end face, and a third floating sealing gap is formed between the second sealing end face and the end face of the floating ring mounting seat. A pump-in dynamic pressure groove is formed on the second sealing end face. The graphite floating ring seal generates significant fluid film bearing capacity on both end faces of the present invention, and non-contact operation can be achieved between the graphite floating ring end face and the components on both sides, reducing the wear and friction of the floating ring end face and extending the service life of the graphite floating ring.

Description

Technical Field

[0001] This invention relates to the field of lubricating oil sealing of bearing cavities in rotating machinery, and specifically to a double-end-face air film supported follow-up type air film end cylindrical surface sealing structure. Background Technology

[0002] Bearing cavities in rotating machinery such as aero engines and turbine compressors require seals to prevent lubricating oil leakage or ingress into the equipment. As the operating parameters of aero engines continue to increase, the requirements for leakage control in bearing cavity lubricating oil seals are also becoming increasingly stringent.

[0003] Floating ring seals, as a type of non-contact micro-gap seal, are widely used in the main bearing cavities of aero-engines. A type of cylindrical seal, the floating ring is suspended from the shaft by gravity when stationary. When the shaft starts, the rotation of the fluid within the gap generates a gas film bearing force, causing the floating ring to overcome gravity and float, thus achieving non-contact operation of the seal. During the floating process, the floating ring is subjected to the gas film bearing force, gravity, and end-face friction. Given a constant gravity, the magnitude of the gas film bearing force and end-face friction becomes the main factor determining the floating ring's floating performance. Improving floating performance and reducing floating ring wear are among the main driving forces in floating ring design.

[0004] Current designs for improving the buoyancy of floating rings primarily focus on structural modifications to enhance the sealing film support force. This is achieved by creating dynamic pressure grooves or throttling orifices on the inner cylindrical surface to increase the local fluid pressure and thus enhance the fluid's carrying capacity, thereby improving the floating ring's buoyancy. However, current floating ring designs only consider the wear and failure of the primary sealing surface, neglecting the wear caused by dry friction between the ring and the primary and secondary sealing surfaces during seal activation. Furthermore, as the operating temperature of aero-engines increases, excessive temperature variations can cause radial displacement of the seal; excessive end-face friction can lead to poor seal following performance. All these factors contribute to contact wear on the inner cylindrical surface of the floating ring, ultimately leading to its failure. Therefore, effectively cooling the seal and reducing radial displacement variations are crucial for the design and application of floating rings in aero-engine bearing cavities. Summary of the Invention

[0005] In view of the problems existing in the prior art, the present invention proposes a double-end air film support follow-up air film end cylindrical sealing structure that can simultaneously achieve floating in the radial and axial directions.

[0006] Compared with the prior art, the technical solution of the present invention is as follows:

[0007] A double-end-face air-film supported follower-type air-film end-cylindrical sealing structure includes a sealing cavity, a floating ring mounting seat fixedly connected to one end of the sealing cavity, and a rotor eccentrically passing through the sealing cavity. A first sealing cavity is provided between the floating ring mounting seat and the sealing cavity. A graphite floating ring, a floating ring seat, and a second grate seal are sequentially installed in the first sealing cavity from top to bottom. A first floating sealing gap exists radially between the rotor and the graphite floating ring. The lower surface of the graphite floating ring is a first sealing end face. A second floating sealing gap exists axially between the first sealing end face and the floating ring seat. A plurality of pump-out dynamic pressure grooves are uniformly formed along the circumferential direction of the first sealing end face. The upper surface of the graphite floating ring is a second sealing end face. A third floating sealing gap exists between the second sealing end face and the end face of the floating ring mounting seat. A plurality of pump-in dynamic pressure grooves are uniformly formed along the circumferential direction of the second sealing end face. The pump-out dynamic pressure grooves communicate with the inner diameter side of the graphite floating ring, and the pump-in dynamic pressure grooves communicate with the outer diameter side of the graphite floating ring.

[0008] Furthermore, the depth of the pump-out dynamic pressure groove is 2 to 20 μm, preferably 3 to 6 μm, and the width h1 of the second floating seal gap is 1 to 10 μm, preferably 2 to 5 μm.

[0009] Furthermore, the depth of the pump-in dynamic pressure groove ranges from 2 to 20 μm, with a preferred value of 3 to 6 μm, and the width h2 of the third floating seal gap ranges from 1 to 10 μm, with a preferred value of 2 to 5 μm.

[0010] Furthermore, the first sealing surface includes a first sealing surface sealing dam, and the pump-out type dynamic pressure groove is formed on the first sealing surface sealing dam; the second sealing end face includes a second sealing surface sealing dam, and the pump-in type dynamic pressure groove is formed on the second sealing surface sealing dam.

[0011] Furthermore, a grate-tooth flow-blocking structure is provided on the inner diameter side of the floating ring seat, and a second grate-tooth seal is installed in the mounting groove on the inner side of the sealing cavity. A second sealing cavity is provided between the grate-tooth flow-blocking structure and the second grate-tooth seal. There is a first fixed sealing gap between the floating ring seat and the rotor radially, and a second fixed sealing gap between the second grate-tooth seal and the rotor radially.

[0012] Furthermore, the sealing cavity is provided with a first vent and a second vent, the second vent being connected to the second sealing cavity, and the two sides of the second sealing cavity being connected to the first fixed sealing gap and the second fixed sealing gap, respectively; the first vent is connected to the first sealing cavity.

[0013] Furthermore, an auxiliary sealing ring is provided in the sealing ring mounting groove of the floating ring seat, an elastic element is provided axially between the floating ring seat and the sealing cavity, and an anti-rotation pin is installed in the pin hole of the floating ring seat.

[0014] Furthermore, a retaining ring is provided between the second tooth seal and the sealing cavity for axial positioning of the second tooth seal.

[0015] The working principle of this invention is as follows:

[0016] In a zero-speed, pressureless state, the graphite floating ring will be suspended on the rotor, at which point the eccentricity of the first floating seal gap reaches its maximum. Due to the elastic force of the elastic element, the floating ring seat will directly contact the graphite floating ring, pressing the graphite floating ring tightly against the floating ring mounting seat. At this time, both the second and third floating seal gaps are zero, and the end-face friction resistance is at its maximum. A higher pressure is introduced into the second sealing cavity through the second vent, at which point the graphite floating ring is under zero-speed static pressure conditions. The gas pressure is still relatively high after being throttled by the grate-tooth flow-blocking structure, and after entering the first sealing cavity, the airflow is divided into two streams: one stream flows axially into the first fixed sealing gap and flows out of the first sealing cavity after throttling; the other stream flows radially into the pump-out dynamic pressure groove on the first sealing end face, causing the graphite floating ring to overcome the elastic force of the elastic element and disengage from the floating ring seat. The airflow is throttled by the second fixed sealing gap and divided into two parts. One part flows out of the cavity through the first air hole, and the other part flows radially into the pump-in dynamic pressure groove on the second sealing end face. After being throttled by the third floating sealing gap, it flows out of the first sealing cavity, causing the graphite floating ring to overcome the pressure of the second fixed sealing gap and thus detach from the contact with the floating ring mounting seat, forming the third floating sealing gap and realizing the static pressure opening of the graphite floating ring. At this time, since the graphite floating ring is no longer in contact with the sealing components on both sides, the end face friction is minimized, facilitating the follow-up movement between the graphite floating ring and the rotor.

[0017] Under high speed and pressure, the graphite floating ring will follow the rotor's motion due to the contact friction of the main sealing surface. This motion enhances the pumping effect of both the pump-out and pump-in dynamic pressure grooves, increasing the opening force on both sides of the graphite floating ring. Because the pressure at the outlet of the first sealing cavity is lower, and the pumping effect of the pump-in dynamic pressure groove is stronger, under certain pressure conditions, the forces on both sides of the graphite floating ring can be balanced. The forces on both sides must meet the following conditions:

[0018] F ph =F pl

[0019] For floating ring seats, the following conditions must be met between the elastic force and the force of the second sealing gap:

[0020] F pl =F p1 +F s +F p4 ±F f .

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0022] 1) By opening dynamic pressure grooves with pumping capabilities on both ends of the graphite floating ring, the present invention can generate gas film reaction force on both ends simultaneously, causing the end face of the graphite floating ring to disengage from the end face of the retaining ring. On the one hand, this can reduce the contact friction of the end face and improve the floating performance of the graphite floating ring; on the other hand, it can reduce the wear of the end face of the graphite floating ring, prevent the seal from wearing and failing, and extend the service life of the seal.

[0023] 2) The first sealing cavity of the present invention is equipped with a second grate seal, and a grate flow obstruction structure is provided on the inner diameter side of the floating ring seat. High-pressure cooling gas is introduced into the air inlet between the two-stage grate sealing rings to prevent the lubricating oil in the bearing cavity from leaking outward. The cooling air enters the gap between the inner and outer circular surfaces of the floating ring after being depressurized by the retaining ring grate ring and pumped by the spiral groove. It plays a cooling role when the graphite floating ring is overheated during operation. Attached Figure Description

[0024] Figure 1 This is a cross-sectional schematic diagram of the sealing structure of the present invention;

[0025] Figure 2 This is a three-dimensional structural diagram of the present invention;

[0026] Figure 3 This is a schematic diagram of the groove structure on the low-pressure side end face of the graphite floating ring of the present invention;

[0027] Figure 4 This is a schematic diagram of the high-pressure side end face groove structure of the graphite floating ring of the present invention;

[0028] Figure 5 This is a schematic diagram of the sealing gap of the present invention;

[0029] Figure 6 This is a schematic diagram of the airflow distribution of the present invention;

[0030] Figure 7 This is a force analysis diagram of the double-end air film floating ring of the present invention;

[0031] Figure 8 This is a force analysis diagram of the actual retaining ring of the present invention.

[0032] In the diagram: 1. Rotor; 2. Graphite floating ring; 21. First sealing end face; 22. Second sealing end face; 23. Pump-out type dynamic pressure groove; 24. Pump-in type dynamic pressure groove; 25. First sealing surface sealing dam; 26. Second sealing surface sealing dam; 3. First sealing cavity; 31. First floating sealing gap; 32. Second floating sealing gap; 33. Third floating sealing gap; 34. Floating ring seat; 341. Grate-tooth flow-blocking structure; 35. Elastic element; 36. Auxiliary sealing ring; 37. Anti-rotation pin; 4. Sealing cavity; 41. First vent; 42. Second vent; 43. Second grate-tooth seal; 5. Floating ring mounting seat; 51. Screw; 6. Second sealing cavity; 61. Snap ring; 11. First fixed sealing gap; 12. Second fixed sealing gap. Detailed Implementation

[0033] The present invention will be further described below with reference to the accompanying drawings, but the scope of protection of the present invention is not limited to the scope described.

[0034] Please refer to Figure 1-4 A double-end-face air-film supported follower-type air-film end-cylindrical sealing structure includes a sealing cavity 4, a floating ring mounting seat 5 fixedly connected to one end of the sealing cavity 4, and a rotor 1 eccentrically passing through the sealing cavity 4. A first sealing cavity 3 is provided between the floating ring mounting seat 5 and the sealing cavity 4. A graphite floating ring 2, a floating ring seat 34, and a second grate seal 43 are installed sequentially from top to bottom in the first sealing cavity 3. A first floating sealing gap 31 is provided radially between the rotor 1 and the graphite floating ring 2. The lower surface of the graphite floating ring 2 is a first sealing end face 21. There is a second floating sealing gap 32 between the first sealing end face 21 and the floating ring seat 34 in the axial direction. Several pump-out dynamic pressure grooves 23 are evenly opened along the circumferential direction of the first sealing end face 21. The upper surface of the graphite floating ring 2 is the second sealing end face 22. There is a third floating sealing gap 33 between the second sealing end face 22 and the end face of the floating ring mounting seat 5. Several pump-in dynamic pressure grooves 24 are evenly opened along the circumferential direction of the second sealing end face 22. The pump-out dynamic pressure grooves 23 are connected to the inner diameter side of the graphite floating ring 2, and the pump-in dynamic pressure grooves 24 are connected to the outer diameter side of the graphite floating ring 2.

[0035] Please refer to Figure 3 and 4 Furthermore, the first sealing surface 21 includes a first sealing surface sealing dam 25, and a pump-out type dynamic pressure groove 23 is provided on the first sealing surface sealing dam 25; the second sealing end face 22 includes a second sealing surface sealing dam 26, and a pump-in type dynamic pressure groove 24 is provided on the second sealing surface sealing dam 26.

[0036] The floating ring seat 34 has a grate-tooth flow-blocking structure 341 on its inner diameter side. The second grate-tooth seal 43 is installed in the mounting groove on the inner side of the sealing cavity 4. A second sealing cavity 6 is provided between the grate-tooth flow-blocking structure 341 and the second grate-tooth seal 43. There is a first fixed sealing gap 11 between the floating ring seat 34 and the rotor 1 in the radial direction. There is a second fixed sealing gap 12 between the second grate-tooth seal 43 and the rotor 1 in the radial direction.

[0037] The sealed cavity 4 has a first vent 41 and a second vent 42. The second vent 42 is connected to the second sealed cavity 6. The two sides of the second sealed cavity 6 are connected to the first fixed sealing gap 11 and the second fixed sealing gap 12, respectively. The first vent 41 is connected to the first sealed cavity 3. Pressurized gas enters the second sealed cavity 6 through the second vent 42 and flows to both sides through the first fixed sealing gap 11 and the second fixed sealing gap 12, respectively.

[0038] An auxiliary sealing ring 36 is provided in the sealing ring mounting groove of the floating ring seat 34. An elastic element 35 is provided between the floating ring seat 34 and the sealing cavity 4 axially. An anti-rotation pin 37 is installed in the pin hole of the floating ring seat 34. The outer surface of the anti-rotation pin 47 is provided with an external thread, and the pin hole is provided with a matching internal thread. The anti-rotation pin 37 is threadedly connected to the pin hole.

[0039] A retaining ring 61 is provided between the second tooth seal 43 and the sealing cavity 4. The retaining ring 61 is used to axially position the second tooth seal 43.

[0040] In this embodiment, the floating ring mounting base 5 is fixed to the sealing cavity 4 by screws 51.

[0041] Reference Figures 3 to 5 The inner diameter and outer diameter of the first sealing end face 21 are r and r, respectively. ih and r oh Inner diameter r ih The groove is connected to the inner diameter side of the graphite floating ring 2; the groove radius of the pump-out type dynamic pressure groove 23 is r. gh The radial widths of the pump-out dynamic pressure groove 23 and the first sealing end face sealing dam 25 are respectively (r gh -r ih ), (r oh -r gh The depth of the pump-out type dynamic pressure groove 23 ranges from 2 to 20 μm, with a preferred value of 3 to 6 μm; the width of the second floating seal gap h1 is 1 to 10 μm, with a preferred value of 2 to 5 μm.

[0042] The inner and outer diameters of the second sealing end face 22 are r and r, respectively. il and r ol Inner diameter r il The groove is connected to the inner diameter side of the graphite floating ring 2; the groove radius of the pump-in dynamic pressure groove 24 is r. glThe radial widths of the pump-in dynamic pressure groove 24 and the second sealing end face sealing dam 26 are respectively (r ol -r gl ), (r gl -r il The depth of the pump-in dynamic pressure groove 24 ranges from 2 to 20 μm, with a preferred value of 3 to 6 μm; the width of the third floating seal gap h2 ranges from 1 to 10 μm, with a preferred value of 2 to 5 μm.

[0043] Please refer to Figures 6 to 8 Axial force analysis was performed on both sides of the graphite floating ring 2. The pressure of the high-pressure cooling air entering through the air inlet is p1, which is relatively high. After the high-pressure cooling air is depressurized by the grate-shaped flow-blocking structure 341, the pressure drops to p3. Thereafter, the airflow splits into two streams at the inner diameter of the high-pressure side of the graphite floating ring 2. One stream is pumped out by the dynamic pressure groove 23, and after depressurization by the end face gap, the pressure changes to p4. The pressure of this medium remains basically constant and does not change with other pressure changes. The other stream enters the first floating sealing gap 31, and after depressurization by the first floating sealing gap 31, the pressure drops to p5. The low-pressure side pressure p5 is always lower than the high-pressure side pressure p3, so the sealing gas can play a good sealing role for the lubricating oil in the bearing cavity. Part of the airflow at p4 flows to the outside through the first air hole 41, and the other part is pumped back by the dynamic pressure groove 24, depressurized by the sealing gap to p5, and flows out of the first sealing cavity 3 radially. The pressure p5 is always less than p4.

[0044] The high-pressure side pressures of the near-axial surface graphite floating ring 2 are p3 and p5, respectively, with the high-pressure side pressure p3 being much greater than the low-pressure side pressure p5. The closing force generated by the high-pressure side gas medium on the first sealing end face 21 is F. ph The closing force generated by the low-pressure side gas medium on the second sealing end face 22 is F. pl The floating ring seat 34 is subjected to a closing force F on its right side. ph The opening force is the same as that on the first sealing end face 21 of the graphite floating ring 2; the end face area of ​​the left grate-tooth flow-blocking structure 341 of the floating ring seat 34 is A1, and the pressure it experiences is the high-pressure cooling air pressure p1. Therefore, the closing force F experienced by the end face of the left grate-tooth flow-blocking structure 341 of the floating ring seat 34 is... p1 =A1×p1; The area of ​​the remaining end face of the floating ring seat 34 on the left side of the grating-tooth flow obstruction structure 341 is A2, and the pressure it experiences is the outlet pressure p4. Then, the closing force F experienced by the other end faces on the left side of the floating ring seat 34 is... p4 =A2×p4.

[0045] In this embodiment, the elastic element 35 is a spring. The spring is in a compressed state during operation, and the closing force it generates on the floating ring seat 34 is F. sIt should be noted that the spring force is directly proportional to the spring compression; as the spring compression increases, the spring force gradually increases. The frictional force between the floating ring seat 34 and the sealing cavity 4 is F. f However, the direction of friction is undetermined.

[0046] Taking the graphite floating ring 2 as the object of force analysis, when the sealing gaps on both sides are the same, the pressure p3 on the side of the second floating sealing gap 32 is higher than the pressure p5 on the side of the third floating sealing gap 33. In the design, since the pumping capacity of the pump-in type dynamic pressure groove 24 is stronger than that of the pump-out type dynamic pressure groove 23, the peak pressure p of the second sealing end face 22 is... lmax Greater than the peak pressure p at the first sealing end face hmax The opening forces on both sides can be balanced, meaning that the axial force satisfies:

[0047] F ph =F pl

[0048] Assume the area of ​​the first sealing end face 21 is A h The radial pressure distribution is p h (r), the area of ​​the second sealing end face 22 is A l The radial pressure distribution is p l (r), then the resultant force F of the air film opening force on both sides of the gap. ph and F pl They are respectively

[0049]

[0050] To prevent uneven force distribution on both ends of the graphite floating ring 2, which could generate an overturning moment and cause the sealing ring to deflect, affecting the end face clearance, it is necessary to ensure the resultant force F of the gap air film opening force. ph and F pl Located on the same axis, the radial width (r) of the pump-out type dynamic pressure groove 23 is... gh -r ih It should be smaller than the radial width (r) of the pump-in dynamic pressure groove 24. ol -r gl ),Right now:

[0051] (r gh -r ih )<(r ol -r gl )

[0052] When the width h1 of the second floating seal gap is less than the width h2 of the third floating seal gap, the pressure on the first sealing end face 21 increases, and the pressure on the second sealing end face 22 decreases. Therefore, the opening forces on both sides of the graphite floating ring 2 are no longer balanced, and the opening force F of the second floating seal gap 32 increases. ph The opening force F on the side greater than the third floating seal gap 33 plThe graphite floating ring 2 is subjected to an opening force F ph The force moves towards the third floating seal gap 33, increasing the width h1 of the second floating seal gap 32 and decreasing the width h2 of the third floating seal gap 33. As the gaps on both sides change, the pressure and opening force on both sides of the floating ring also change accordingly, with the opening force F on the second floating seal gap 32 side... ph The opening force F on the third floating seal gap 33 side decreases as the gap increases. pl The opening force increases as the gap decreases. When the floating ring moves to a certain position and the opening forces on both sides are equal, the floating ring reaches equilibrium again. When the width h1 of the second floating sealing gap 32 is greater than the width h2 of the third floating sealing gap 33, the change in the gas film opening force is similar to the above process. Through the above principle, the graphite floating ring 2 can maintain a suitable sealing gap.

[0053] Taking the floating ring seat 34 as the object of force analysis, when it is in equilibrium, its axial force satisfies:

[0054] F ph =F p1 +F p4 +F s ±F f

[0055] When the rotor 1 operates at too low a speed, the graphite floating ring 2 also operates at a low speed, and the high-voltage side opening force F... ph The closing force on the left side of the floating ring seat 34 remains unchanged as the opening and closing forces decrease. The net force of the opening and closing forces causes the floating ring seat 34 to move to the right. During this process, the deformation of the elastic element 35 decreases, and the elastic force F... s As the load decreases, the resultant force of the closing force on the left side decreases. When the floating ring seat 34 moves to a certain position, the opening force and closing force reach equilibrium again, and the floating ring seat 34 reaches a new equilibrium state. The operating principle of the floating ring seat 34 is similar when the rotor 1 is too large. Through the above principle, the floating ring seat 34 can automatically adjust to the equilibrium position.

Claims

1. A double-end-face air-film supported follow-up air-film end cylindrical sealing structure, comprising a sealing cavity (4), a floating ring mounting seat (5) fixedly connected to one end of the sealing cavity (4), and a rotor (1) eccentrically passing through the sealing cavity (4), wherein a first sealing cavity (3) is provided between the floating ring mounting seat (5) and the sealing cavity (4), and a graphite floating ring (2), a floating ring seat (34) and a second toothed seal (43) are sequentially installed in the first sealing cavity (3) from top to bottom, and a first floating sealing gap (31) is provided radially between the rotor (1) and the graphite floating ring (2), characterized in that The lower surface of the graphite floating ring (2) is the first sealing end face (21). There is a second floating sealing gap (32) between the first sealing end face (21) and the floating ring seat (34) in the axial direction. The first sealing end face (21) is uniformly provided with a plurality of pump-out dynamic pressure grooves (23) along its circumferential direction. The upper surface of the graphite floating ring (2) is the second sealing end face (22). There is a third floating sealing gap (33) between the second sealing end face (22) and the end face of the floating ring mounting seat (5). The second sealing end face (22) is uniformly provided with a plurality of pump-in dynamic pressure grooves (24) along its circumferential direction. The pump-out dynamic pressure grooves (23) are connected to the inner diameter side of the graphite floating ring (2). The pump-in dynamic pressure grooves (24) are connected to the outer diameter side of the graphite floating ring (2).

2. The double-end-face air-film support follow-up type air-film end cylindrical sealing structure according to claim 1, characterized in that... The depth of the pump-out type dynamic pressure groove (23) is 2 to 20 μm, and the width of the second floating seal gap is... h 1 represents 1–10 μm.

3. The double-end-face air-film support follow-up type air-film end cylindrical sealing structure according to claim 1, characterized in that... The depth of the pump-in dynamic pressure groove (24) ranges from 2 to 20 μm, and the width of the third floating seal gap... h 2 is 1–10 μm.

4. The double-end-face air-film support follow-up type air-film end cylindrical sealing structure according to claim 1, characterized in that... The first sealing end face (21) includes a first sealing surface sealing dam (25), and the pump-out type dynamic pressure groove (23) is provided on the first sealing surface sealing dam (25); the second sealing end face (22) includes a second sealing surface sealing dam (26), and the pump-in type dynamic pressure groove (24) is provided on the second sealing surface sealing dam (26).

5. The double-end-face air-film support follow-up type air-film end cylindrical sealing structure according to claim 1, characterized in that... The floating ring seat (34) has a toothed flow-blocking structure (341) on its inner diameter side. The mounting groove on the inner side of the sealing cavity (4) is equipped with a second toothed seal (43). A second sealing cavity (6) is provided between the toothed flow-blocking structure (341) and the second toothed seal (43). There is a first fixed sealing gap (11) between the floating ring seat (34) and the rotor (1) in the radial direction. There is a second fixed sealing gap (12) between the second toothed seal (43) and the rotor (1) in the radial direction.

6. The double-end-face air-film support follow-up type air-film end cylindrical sealing structure according to claim 5, characterized in that... The sealing cavity (4) is provided with a first air hole (41) and a second air hole (42). The second air hole (42) is connected to the second sealing cavity (6). The two sides of the second sealing cavity (6) are connected to the first fixed sealing gap (11) and the second fixed sealing gap (12) respectively. The first air hole (41) is connected to the first sealing cavity (3).

7. The double-end-face air-film support follow-up type air-film end cylindrical sealing structure according to claim 5, characterized in that... An auxiliary sealing ring (36) is provided in the sealing ring mounting groove of the floating ring seat (34), and an elastic element (35) is provided axially between the floating ring seat (34) and the sealing cavity (4). An anti-rotation pin (37) is installed in the pin hole of the floating ring seat (34).

8. The double-end-face air-film support follow-up type air-film end cylindrical sealing structure according to claim 5, characterized in that... A retaining ring (61) for axial positioning of the second tooth seal (43) is provided between the second tooth seal (43) and the sealing cavity (4).

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