A gas seal cover sealing structure for a lower oil guide pan of a generator

Abstract

The application discloses a kind of air seal cover sealing structure for generator lower oil guide basin, it is related to the sealing technical field of hydroelectric generator, including main shaft, oil guide basin body and air seal cover, air seal cover is set up with through hole, the inner wall of through hole is equipped with installation groove, installation groove is equipped with air seal ring, air seal ring includes multiple sealing units, sealing unit includes sealing element, support and elastic element, support is located in installation groove, and it has displacement space in radial direction relative to air seal cover, elastic element is connected between corresponding support and air seal cover, for supporting elastic constraint in working position, sealing element extends installation groove along radial direction, and it is close to main shaft setting;Two adjacent sealing elements are mutually abutting in circumferential direction, and multiple sealing elements are arranged in the outer periphery of main shaft around.The above-mentioned scheme can solve the problem that the gap increases due to the deformation of the felt in the existing sealing structure and cannot be compensated, and the sealing element is easily worn out and failed due to rigid collision when jumping in the radial direction.

Description

Technical Field

[0001] This application relates to the field of sealing technology for hydro-generators, and in particular to a gas seal cover sealing structure for the lower oil guide pan of a generator. Background Technology

[0002] In hydro-generator sets, the lower oil guide basin is used to hold bearing lubricating oil, and its top is equipped with an air seal cover through which the main shaft vertically passes. To prevent oil mist from escaping from the gap between the air seal cover and the main shaft, traditional sealing structures often use a combination of labyrinth teeth and felt. The sealing teeth have a fixed gap during operation, and the seal mainly relies on the contact between the felt and the main shaft. However, the felt gradually deforms under pressure during long-term operation, increasing the gap and failing to automatically compensate, leading to poor sealing and the escape of large amounts of oil mist. This escaped oil mist enters the generator, contaminating components such as stator bars and rotor poles, and forming a black oil layer on surfaces such as the frame and base plate, accelerating insulation aging and increasing maintenance difficulty and cost. Furthermore, if the sealing structure makes rigid contact with the main shaft, it may cause excessive shaft current, seriously threatening the safe operation of the generator. Although some existing technologies use split-type sealing rings, their radial adjustment capability is limited, unable to adapt to the large radial runout caused by main shaft start-up and shutdown and load changes, and lacks convenient on-site gap adjustment methods.

[0003] Chinese utility model patent CN221035175U, authorized and announced on November 17, 2023, entitled "An oil mist overflow prevention device for the lower oil guide basin of a hydropower station generator set," discloses an oil mist overflow prevention device including a base and a felt layer. The base is mounted on the lower oil guide basin cover, and a cover is mounted on the base. The inner surface of the upper end of the cover is covered with a felt layer, one end of which is in soft contact with the upper plane of the main shaft. However, this device still uses felt as the main sealing element. During long-term operation, the felt is easily squeezed and deformed, resulting in increased gaps that cannot be automatically compensated for, and the sealing effect decreases significantly with the use time. At the same time, the felt and the main shaft have a fixed soft contact, lacking radial floating and elastic compensation capabilities, and cannot adapt to the large radial runout caused by the start-up and shutdown of the main shaft and load changes. Moreover, the sealing gap cannot be adjusted on-site, making it difficult to fundamentally solve the problem of oil mist escape and the resulting insulation pollution. The aforementioned technical defects have not been effectively resolved. Summary of the Invention

[0004] In order to overcome the shortcomings of the prior art, this application provides a gas seal cover sealing structure for the lower oil guide pan of a generator, so as to solve the problems in the existing sealing structure that the gap increases due to felt deformation and cannot be compensated, and that rigid collisions easily occur during radial runout, leading to wear and failure of the seal.

[0005] To achieve the above objectives, this application adopts the following technical solution: A gas seal cover sealing structure for a generator lower oil guide pan includes a main shaft, an oil guide pan body, and a gas seal cover. The top of the oil guide pan body has an opening, which is closed by the gas seal cover. A through hole is provided on the gas seal cover, through which the main shaft passes vertically. The inner wall of the through hole has a circumferentially extending mounting groove. A gas seal ring is mounted in the mounting groove. The gas seal ring includes multiple sealing units, each including a sealing element, a support element, and an elastic element. Multiple support elements are sequentially arranged within the mounting groove along its extension direction, with at least a portion of each support element located within the mounting groove and positioned relative to the surrounding surface. The air seal cover has a displacement space in the radial direction. The support member has a working position close to the main shaft in the mounting groove, and this working position is limited by the limiting sidewall of the mounting groove. The elastic member is connected between the corresponding support member and the air seal cover to elastically constrain the support member to the working position. The sealing member is fixed to the inner side of the corresponding support member. At least part of the sealing member extends radially out of the mounting groove and is set close to the main shaft. Two adjacent sealing members abut against each other in the circumferential direction, and multiple sealing members are arranged around the outer periphery of the main shaft to achieve a seal between the air seal ring and the main shaft.

[0006] In the above technical solution, the gas seal ring is divided into multiple independent sealing units, each with independent radial floating capability and elastic compensation capability. When the spindle experiences radial runout and impacts a seal, the sealing unit can slightly retract radially outward, while the elastic element is compressed to absorb the impact energy. When the radial runout decreases, the elastic element pushes the sealing unit back to its initial gap or slight contact state with the spindle. This mechanism gives the sealing unit a certain elastic avoidance capability during spindle radial runout, effectively preventing seal breakage, support deformation, or spindle surface scratches caused by rigid collisions, thereby significantly improving the impact resistance and service life of the sealing structure. Simultaneously, since the multiple sealing units are independent in the circumferential direction, local out-of-roundness or eccentricity of the spindle will only affect one or a few sealing units at the corresponding position, without causing the entire sealing ring to fail. Adjacent seals abut against each other in the circumferential direction, and multiple seals are arranged around the outer circumference of the spindle, thus forming a continuous and complete sealing interface along the entire circumference of the spindle.

[0007] Preferably, the seal is made of a composite material of graphite and insulating flexible material.

[0008] Preferably, the mounting groove includes an interconnected mounting portion and a through portion, the axial dimension of the mounting portion is greater than the axial dimension of the through portion, a support member and an elastic member are disposed in the mounting portion, and the radial dimension of the mounting portion is greater than the radial dimension of the support member, so that the support member has displacement space in the radial direction of the mounting portion, the seal member extends to the outside of the spindle via the through portion, and the side wall of the mounting portion near the spindle forms the limiting side wall.

[0009] Preferably, the elastic element is an elastic metal sheet, which is inclined in the circumferential direction relative to the radial direction of the gas seal cover. One end of the elastic metal sheet is fixed to the outer side of the support member, and the other end is pressed against the inner wall of the mounting part.

[0010] Preferably, multiple elastic metal sheets are fixed to the outer side of each support member, and the elastic metal sheets on each support member have the same tilt direction.

[0011] Preferably, the gas seal cover is composed of multiple sealing cover units, which are sequentially spliced ​​together along the circumference. Adjacent sealing cover units are fixed together by connectors, and the mounting slots of the multiple sealing cover units are sequentially connected to form a complete annular groove.

[0012] Preferably, the supports are spaced apart between two circumferentially adjacent supports.

[0013] Preferably, the air seal cover is provided with multiple mounting grooves spaced apart along the axial direction, and each mounting groove corresponds to the installation of an air seal ring; the inner wall of the sealing element is provided with at least one circumferentially extending dividing groove, which divides the inner wall of the sealing element into multiple independent sealing surfaces.

[0014] Preferably, it also includes multiple adjusting plates with various thicknesses. Each adjusting plate includes an operating part and a clamping part. The mounting groove is provided with an adjusting groove in the axial direction. Each sealing unit is provided with at least one adjusting groove. The adjusting groove connects the internal space of the mounting groove with the external space of the oil guide basin body. Multiple adjusting plates are selectively inserted into the mounting groove through the adjusting groove. The support member and the limiting sidewall radially clamp the clamping part. The operating part is located outside the oil guide basin body. The axial cross-sectional dimension of the clamping part is smaller than the axial cross-sectional dimension of the adjusting groove, so that the clamping part can be inserted into the mounting groove through the adjusting groove, or the clamping part can be disengaged from the adjusting groove and the mounting groove.

[0015] Preferably, an axial through-hole is provided between the support member and the sealing member, and the axial cross-sectional dimension of the through-hole is larger than the axial cross-sectional dimension of the clamping part. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the first structure in this application; Figure 2 yes Figure 1 A magnified view of a section at point A in the middle; Figure 3 This is a schematic diagram of the first structural design of the sealing unit in this application; Figure 4 This is a schematic diagram of the structure of the gas seal ring of this application; Figure 5 This is a schematic diagram of the second structure of this application; Figure 6 yes Figure 5A magnified view of a section at point B in the middle; Figure 7 This is a schematic diagram of the second structure of the sealing unit in this application.

[0017] In the figure: 1. Main shaft, 2. Oil guide pan body, 21. Opening, 3. Air seal cover, 31. Through hole, 32. Mounting groove, 321. Mounting part, 322. Limiting side wall, 323. Adjusting groove, 33. Air seal ring, 4. Sealing unit, 41. Sealing element, 411. Support element, 412. Elastic element, 413. Dividing groove, 414. Avoidance hole, 415. Adjusting plate, 5. Operating part, 51. Clamping part, 52. Detailed Implementation

[0018] The technical solutions of this application will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of this application, and not all embodiments. The components of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0019] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, in the description of this application, terms such as "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0020] Example 1: like Figure 1 Character Figure 7As shown, a gas seal cover sealing structure for a generator lower oil guide pan includes a main shaft 1, an oil guide pan body 2, and a gas seal cover 3. The top of the oil guide pan body 2 has an opening 21, which is closed by the gas seal cover 3. A through hole 31 is provided on the gas seal cover 3, through which the main shaft 1 passes vertically. The inner wall of the through hole 31 has a circumferentially extending mounting groove 32. A gas seal ring 4 is mounted in the mounting groove 32. The gas seal ring 4 includes multiple sealing units 41, each including a sealing element 411, a support element 412, and an elastic element 413. Multiple support elements 412 are sequentially arranged within the mounting groove 32 along its extension direction, with at least a portion of each support element 412 located within the mounting groove 32. The support member 412 has a radial displacement space relative to the air seal cover 3. The support member 412 has a working position close to the main shaft 1 in the mounting groove 32, and this working position is limited by the limiting sidewall 323 of the mounting groove 32. The elastic member 413 is connected between the corresponding support member 412 and the air seal cover 3 to elastically constrain the support member 412 to the working position. The sealing member 411 is fixed to the inner side of the corresponding support member 412. At least part of the structure of the sealing member 411 extends radially out of the mounting groove 32 and is set close to the main shaft 1. Two adjacent sealing members 411 abut against each other in the circumferential direction, and multiple sealing members 411 are arranged around the outer periphery of the main shaft 1 to achieve a seal between the air seal ring 4 and the main shaft 1.

[0021] For ease of understanding, some key terms in this embodiment are explained below.

[0022] Gas seal ring 4: A ring-shaped component installed in the mounting groove 32 of the gas seal cover 3 to achieve gas sealing between the spindle 1 and the gas seal cover 3, which is composed of multiple sealing units 41 spliced ​​together circumferentially.

[0023] Sealing unit 41: The basic independent module that constitutes the air seal ring 4. Each sealing unit 41 includes a sealing element 411, a support element 412 and an elastic element 413, and can float radially independently.

[0024] Seal 411: A sealing element that is directly opposite to or in contact with the surface of the spindle 1, and can be made of materials with self-lubricating, high temperature resistance and wear resistance, such as graphite, polytetrafluoroethylene, and flexible graphite composite insulating materials.

[0025] Support member 412: A rigid or semi-rigid member used to support the seal 411 and transmit the force of the elastic member 413 to the seal 411. It is usually made of metal (such as aluminum alloy or stainless steel) or high-strength engineering plastic.

[0026] Elastic element 413: An elastic element connected between the support 412 and the air seal cover 3, providing reset force and preload. Its stiffness should be designed to match the allowable contact pressure and required relief stroke of the spindle 1.

[0027] Limiting sidewall 323: A wall surface within the mounting groove 32 used to limit the inward movement limit of the support member 412. Its position determines the minimum clearance or initial contact pressure between the seal member 411 and the main shaft 1. The surface of the limiting sidewall 323 can be a plane perpendicular to the radial direction, or it can be an arc surface or a slope that matches the outer surface of the support member 412. When the support member 412 is pushed to its innermost position by the elastic member 413, the outer surface of the support member 412 (the side facing away from the main shaft 1) or other limiting structures of the support member 412 comes into contact with the limiting sidewall 323, thereby precisely limiting the minimum clearance or initial contact pressure between the seal member 411 and the main shaft 1.

[0028] Working position: The position where the support member 412 is pushed to the limiting sidewall 323 under the action of the elastic member 413. At this time, there is a preset sealing gap or slight contact between the seal member 411 and the spindle 1. This application describes the implementation method with a preset sealing gap between the seal member 411 and the spindle 1. It should be noted that the "working position" is not an absolutely fixed geometric coordinate, but a dynamic balance reference position determined by the preload of the elastic member 413 and the blocking effect of the limiting sidewall 323. When the spindle 1 is in an ideally aligned state and there is no radial runout, the support member 412 is stably maintained in this working position; when the spindle 1 experiences radial runout and pushes the seal member 411, the support member 412 can overcome the elastic force of the elastic member 413 and move radially outward, temporarily leaving the working position; when the radial runout decreases or disappears, the restoring force of the elastic member 413 pushes the support member 412 back to the working position. Therefore, the working position is essentially the "reset reference" of the sealing unit 41 under static or stable operating conditions, and is the key constraint boundary to ensure that the sealing gap between the sealing element 411 and the spindle 1 is always within the design range.

[0029] Displacement space: refers to the hollow area formed by the radial dimension of the mounting groove 32 being larger than the radial dimension of the support member 412. This space allows the support member 412 to move radially outward a certain distance without rigidly interfering with the inner wall of the mounting groove 32 when pushed by the main shaft 1. The size of the displacement space determines the maximum retraction stroke of the sealing unit 41 and should be designed according to the maximum radial runout that the main shaft 1 may experience.

[0030] Elastic constraint: refers to the continuous elastic force exerted by the elastic element 413 on the support element 412. The direction of this force is towards the main shaft 1 (i.e., radially inward), so that the support element 412 always tends to return to its working position. The stiffness of the elastic constraint should be matched and designed to ensure that the seal 411 and the main shaft 1 maintain effective contact or a small gap under normal operating conditions, while allowing the support element 412 to smoothly retreat when the main shaft 1 experiences large radial runout, avoiding rigid impact.

[0031] In this embodiment, the top of the oil guide pan body 2 refers to the surface located at the upper end when the oil guide pan body 2 is normally placed. The generator main shaft 1 is generally vertically positioned during normal operation, therefore the main shaft 1 passes vertically through the through hole 31. In other possible embodiments, if the main shaft 1 is horizontally positioned, the corresponding end face of the oil guide pan body 2 can also be defined as the "top," making the through hole 31 horizontally positioned, with the main shaft 1 passing horizontally through the through hole 31, without affecting its structural adaptability and sealing reliability.

[0032] To facilitate a clear description of the structure and motion relationships of the present invention, the directional terms such as "circumferential," "radial," "axial," "inner," and "outer" used in this application are all defined based on the central axis of the main shaft 1: the side closer to the central axis of the main shaft 1 is the "inner side," and the side farther from the central axis of the main shaft 1 is the "outer side"; the circumferential direction of the main shaft 1 is "circumferential"; the diametrical direction of the main shaft 1 is "radial"; and the axial direction of the main shaft 1 is "axial."

[0033] The phrase "seal 411 is positioned close to the spindle 1" in this application refers to the inner edge of seal 411 being dynamically fitted to the surface of spindle 1, or a very small gap being maintained between the inner edge of seal 411 and the surface of spindle 1. The specific value of this gap can be set according to actual sealing requirements, the diameter of spindle 1, rotational speed, and allowable leakage rate; for example, it can be set to 0.5mm to 2mm. The sealing between the gas seal ring 4 and spindle 1 described in this application refers to the sealing of gaseous media (such as oil mist), used to prevent lubricating oil mist inside the oil guide pan from escaping to the external environment, while preventing the intrusion of external impurities, ensuring the cleanliness and efficiency of the bearing lubrication system. Therefore, the sealing between the gas seal ring 4 and spindle 1 does not require seal 411 to be completely tightly fitted to spindle 1; in actual operation, a small gap between seal 411 and spindle 1 is permissible. This gap can prevent hard friction wear on spindle 1 and achieve sufficient sealing effect through the labyrinth effect or throttling pressure reduction.

[0034] The radial runout of the generator main shaft 1 is most pronounced during start-up and shutdown, sudden load changes, or mechanical failures. In the aforementioned technical solution, the gas sealing ring 4 is divided into multiple independent sealing units 41, each with independent radial floating capability and elastic compensation capability. When the main shaft 1 experiences radial runout and impacts a seal 411, the sealing unit 41 can slightly retract radially outward, while the elastic element 413 is compressed, absorbing the impact energy. When the radial runout decreases, the elastic element 413 pushes the sealing unit 41 back to its initial gap or slight contact state with the main shaft 1. This mechanism gives the sealing unit 41 a certain elastic avoidance capability during radial runout of the main shaft 1, effectively preventing damage to the seal 411, deformation of the support 412, or scratches on the surface of the main shaft 1 caused by rigid collisions, thereby significantly improving the impact resistance and service life of the sealing structure. Meanwhile, since the multiple sealing units 41 are independent of each other in the circumferential direction, the local out-of-roundness or eccentricity of the main shaft 1 will only affect one or a few sealing units 41 at the corresponding position, and will not cause the entire sealing ring to fail.

[0035] In the above technical solution, the limiting sidewall 323 of the mounting groove 32 can accurately position the radial floating limit of the support member 412. When the elastic member 413 pushes the support member 412 to the innermost working position, the support member 412 abuts against the limiting sidewall 323. At this time, the seal member 411 and the spindle 1 have a designed initial gap or are in slight contact. This working position ensures that the seal member 411 will not excessively press against the spindle 1 under any working condition (avoiding hard friction), nor will it lose its sealing effect due to excessive yielding. The limiting sidewall 323 can adopt a planar structure perpendicular to the radial direction, or it can adopt an arc surface or inclined surface structure that matches the outer surface of the support member 412 to improve the stability of the limiting.

[0036] In the above technical solution, two adjacent seals 411 abut against each other in the circumferential direction, and multiple seals 411 are arranged around the outer periphery of the main shaft 1, thereby forming a continuous and complete sealing interface in the entire circumferential direction of the main shaft 1. The abutment between adjacent seals 411 can be direct end-face contact or indirect abutment achieved through gap compensation elements (such as elastic gaskets). When the main shaft 1 experiences radial runout, causing a seal 411 to retract outward, the circumferential abutment between adjacent seals 411 can be maintained by the flexible deformation of the seal 411 itself or the lateral component force of the elastic element 413, without creating a significant circumferential leakage channel.

[0037] Preferred, such as Figure 3 As shown, the support members 412 are spaced apart between two adjacent support members in the circumferential direction.

[0038] In the above technical solution, a certain gap is maintained between adjacent support members 412 in the circumferential direction instead of them abutting against each other. This gap allows each sealing unit 41 to be independent of each other in the radial direction: when the main shaft 1 experiences radial runout or local deformation, the affected sealing unit 41 can independently retract outward, and its movement will not be transmitted to the adjacent sealing unit 41 through the support member 412, thereby avoiding overall deformation or jamming of the sealing ring due to a chain reaction. At the same time, this gap provides a basis for the circumferential contact between two adjacent sealing members 411—when the elastic member 413 drives the sealing unit 41 to move radially closer to the main shaft 1, it will not be hindered by the rigid contact of the adjacent support members 412, thus preventing the sealing member 411 from failing to reach the expected position and ensuring that the two adjacent sealing members 411 remain tightly abutted.

[0039] It should be noted that the "spaced arrangement" refers to the fact that two adjacent support members 412 do not contact each other in the circumferential direction, and a preset gap is left between them. The specific size of this gap should be designed to match the diameter of the spindle 1, the number of sealing units 41, the coefficient of thermal expansion of the material, and the allowable radial displacement. It is worth noting that although the support members 412 are spaced apart, the sealing members 411 fixed to their inner sides still remain tightly pressed against each other (as described in Embodiment 1), so the integrity of the sealing ring in the circumferential direction will not be affected.

[0040] Understandably, in one embodiment, the air seal cover 3 is provided with a plurality of mounting grooves 32 spaced apart along the axial direction, and each mounting groove 32 is provided with an air seal ring 4; the inner sidewall of the sealing member 411 is provided with at least one dividing groove 414 extending circumferentially, and the dividing groove 414 divides the inner wall of the sealing member 411 into a plurality of independent sealing surfaces.

[0041] In the above technical solution, when multiple mounting grooves 32 and multiple air sealing rings 4 are used, each air sealing ring 4 forms a multi-stage series sealing structure in the axial direction. Oil mist needs to pass through each stage of the sealing element 411 in sequence before it can escape, significantly extending the leakage path. At the same time, the chambers between each stage can serve as buffer chambers, allowing the oil mist to condense and flow back within the chambers, greatly improving the sealing effect. When the dividing groove 414 is used, the inner wall of the sealing element 411 is divided into multiple independent sealing surfaces. Each surface can independently form a sealing contact or a small gap with the surface of the main shaft 1. The multi-lip design increases the redundancy of the seal and forms a labyrinthine throttling channel through the dividing groove 414, further reducing the leakage rate. The two features can be implemented individually or in combination. When the two features are implemented in combination, the multi-stage air sealing rings 4 and the multi-lip structure on each stage of the sealing element 411 work together to form a composite seal of "axial multi-stage × circumferential multi-lip", which has a significantly better sealing performance than a single structure.

[0042] It should be noted that the "axial spacing" refers to the arrangement of multiple mounting grooves 32 along the axis of the main shaft 1, with spacing between them. The "dividing groove 414" refers to an annular groove formed on the inner wall of the seal 411 (i.e., the side opposite to the main shaft 1). Its cross-sectional shape can be V-shaped, U-shaped, or rectangular, and the groove width and depth can be designed according to the size of the seal 411 and the required sealing effect. The number of dividing grooves 414 can be one, two, or more, and multiple dividing grooves 414 divide the inner wall of the seal 411 into multiple axially arranged sealing lips.

[0043] Those skilled in the art will understand that in the above embodiments, the gas seal ring 4 is composed of multiple sealing units 41 arranged end to end. However, without departing from the concept of the present invention, the following alternative solutions can also be adopted: The number of sealing units 41 can be flexibly selected according to the diameter of the spindle 1. For example, when the diameter is small, 4 to 6 sealing units 41 can be used, and when the diameter is large, 8 to 12 or more sealing units 41 can be used to ensure that the arc length of each sealing unit 41 is appropriate and easy to process and install.

[0044] The sealing element 411 and the support element 412 can be fixed by bonding, screw connection, snap-fit ​​connection or integral molding, as long as it is ensured that the sealing element 411 will not fall off or rotate relative to the support element 412 when it moves radially.

[0045] In addition to the elastic metal sheet preferred in the following embodiments, the elastic element 413 can also be a helical spring, wave spring, rubber elastomer or other element with energy storage and release functions, as long as it can elastically constrain the support 412 to the working position and provide a restoring force after radial retraction.

[0046] The cross-sectional shape of the mounting groove 32 is not limited to rectangular or stepped, but may also be trapezoidal, dovetail-shaped or other geometry that can accommodate the support 412 and provide radial guidance for it.

[0047] Example 2: Based on Example 1, the sealing element 411 is made of a composite material of graphite and insulating flexible material.

[0048] In the above technical solution, graphite itself has excellent self-lubricating properties, which significantly reduces the coefficient of friction between the seal 411 and the main shaft 1, thereby reducing frictional heat and wear, and extending the service life of the seal 411 and the main shaft 1. Furthermore, graphite has good thermal stability and chemical inertness, maintaining stable performance in the high-temperature environment (typically 60℃~100℃) generated by generator operation, and is resistant to corrosion from acidic or alkaline decomposition products that may be present in the lubricating oil. The composite of the insulating flexible material (such as rubber, silicone, fluororubber, polyurethane, or flexible epoxy resin, etc.) with graphite imparts a certain elastic deformation capacity to the seal 411. This elastic deformation capacity allows the seal 411 to adapt to deformation when the main shaft 1 undergoes axial movement, reducing hard impacts and minimizing damage to the sealing structure. In addition, the two adjacent seals 411 can achieve surface contact through the micro-deformation of the flexible material, thereby better forming a complete annular sealing structure. During the radial displacement of the sealing unit 41, the contact surface between the two adjacent seals 411 can be adjusted synchronously with the displacement, ensuring that no gaps always occur. Pure graphite has good electrical conductivity. If the seal 411 comes into contact with the spindle 1, it may form a shaft current path, leading to electro-corrosion. In this embodiment, an insulating flexible material forms an insulating barrier between the graphite particles, significantly increasing the volume resistivity of the composite material. Even if the seal 411 comes into contact with the spindle 1, no harmful shaft current will be generated, thus avoiding electrical damage to the bearing and spindle 1. An insulating structure is provided in the lower middle position of the lower oil guide basin 2, making the lower oil guide basin 2 completely insulated from the external structure. Therefore, only appropriate insulation performance needs to be considered between the gas seal cover 3 and the spindle 1.

[0049] The graphite mentioned above is conventional graphite, which has excellent self-lubricating, high temperature resistance, and corrosion resistance properties. After being combined and fused together with an insulating flexible material, it retains the inherent self-lubricating, high temperature resistance, and corrosion resistance properties of graphite. At the same time, the insulating flexible material gives the finished product a certain degree of flexibility and plasticity. Meanwhile, the insulating flexible material blocks the conductive path of the graphite, so that the seal 411 as a whole has electrical insulation properties. Here, insulation does not mean absolutely non-conductive. It just means that compared with the graphite material itself, the resulting seal 411 has a certain degree of flexibility and plasticity and is less conductive.

[0050] Those skilled in the art will understand that, without departing from the concept of the present invention, the composite material composition of the seal 411 can adopt various parallel schemes. For example, graphite can be composited with rubber-like materials, such as graphite blended with nitrile rubber, fluororubber, or silicone rubber and vulcanized, combining the lubricity of graphite and the elasticity of rubber; or graphite can be composited with engineering plastics, such as graphite blended or sintered with polytetrafluoroethylene (PTFE), polyetheretherketone (PEEK), or polyimide (PI), suitable for higher temperatures or harsher chemical environments; or graphite can be composited with thermoplastic elastomers, such as graphite blended with thermoplastic polyurethane (TPU) or styrene-based elastomers (SEBS) and injection molded, facilitating mass production; or a multi-layer composite structure can be adopted, such as using an insulating flexible material as the matrix and a graphite coating or graphite film composited on the surface, ensuring both the self-lubricating properties of the contact surface and the overall insulation performance.

[0051] It is understood that in other embodiments, the seal 411 may also be made of other materials commonly used in the sealing field. For example, pure polytetrafluoroethylene (PTFE) or its filled modified materials (such as filled carbon fiber, glass fiber, molybdenum disulfide, etc.); high-performance engineering plastics such as polyimide (PI) or polyether ether ketone (PEEK); impregnated graphite or resin graphite (i.e., resin or metal is impregnated into the pores of graphite through an impregnation process to reduce air permeability and increase strength); and carbon fiber reinforced composite materials.

[0052] To facilitate understanding of this embodiment, the relevant terms are explained below.

[0053] The term "insulating flexible material" refers to polymeric materials that have electrical insulation properties and a certain degree of flexibility and elasticity, including but not limited to natural rubber, nitrile rubber, chloroprene rubber, silicone rubber, fluororubber, ethylene propylene diene monomer (EPDM), polyurethane (PU), polyvinyl chloride (PVC), polyethylene (PE), polypropylene (PP), polytetrafluoroethylene (PTFE), and various thermoplastic elastomers (TPE).

[0054] The term "composite molding" refers to the process of combining graphite and insulating flexible materials into one through physical or chemical methods. Specific molding methods include, but are not limited to, mechanical blending followed by compression molding, injection molding, extrusion molding, or spraying, impregnating, or coating graphite powder onto the surface of the insulating flexible material substrate, or combining the two through hot pressing and sintering.

[0055] In this application, "electrical insulation performance" refers to a significant reduction in conductivity and a substantial increase in volume resistivity of the seal 411 compared to pure graphite material. This ensures that when the seal 411 comes into contact with the spindle 1, the leakage current flowing through the spindle 1, the seal 411, the gas seal cover 3, and ground is insufficient to cause electro-corrosion damage to the bearing or the spindle 1. Typically, the volume resistivity is greater than 10 ohms. 4A value of Ω·cm can be considered as having basic insulation capability, preferably greater than 10. 6 Ω·cm.

[0056] The "shaft current" refers to the current that may be generated at the two ends of the main shaft 1 due to magnetic circuit asymmetry, static charge accumulation, etc. in large rotating motors such as hydro generators. In this embodiment, by making the seal 411 have electrical insulation properties, the path of shaft current from the main shaft 1 through the seal 411 and the gas seal cover 3 to the ground is cut off, thereby protecting the bearing.

[0057] Example 3: like Figure 2 and Figure 3 As shown, based on Embodiment 1 or Embodiment 2, the mounting groove 32 includes a mounting portion 321 and a through portion 322 that are interconnected. The axial dimension of the mounting portion 321 is larger than the axial dimension of the through portion 322. The support member 412 and the elastic member 413 are disposed in the mounting portion 321. The radial dimension of the mounting portion 321 is larger than the radial dimension of the support member 412, so that the support member 412 has displacement space in the radial direction of the mounting portion 321. The sealing member 411 extends to the outside of the main shaft 1 through the through portion 322. The side wall of the mounting portion 321 near the main shaft 1 forms the limiting side wall 323.

[0058] In the above technical solution, by adopting a stepped structure design for the mounting groove 32 (i.e., the axial dimension of the mounting portion 321 is larger than the axial dimension of the through portion 322), the support member 412 and the elastic member 413 can be accommodated within the mounting portion 321, while the through portion 322 only allows the seal member 411 to pass through. The area within the mounting portion 321 provides radial displacement space for the support member 412, allowing the support member 412 to slightly retract outward or return inward according to the radial runout of the spindle 1. The size of the displacement space should be adaptively designed according to the maximum possible radial runout of the spindle 1. The limiting sidewall 323, as the sidewall of the mounting portion 321 near the spindle 1, abuts against the support member 412 when it is pushed to the innermost side by the elastic member 413, precisely defining the minimum gap between the seal member 411 and the spindle 1. The beneficial effects of the above technical solution include: 1. Providing reliable radial displacement space and axial limiting for the support member 412, ensuring that the sealing unit 41 can work stably; 2. Guiding and straightening the sealing member 411 through the through part 322, improving the smoothness of the movement of the sealing member 411; 3. The cooperation between the limiting side wall 323 and the support member 412 realizes the precise reset of the working position, ensuring the consistency of the sealing gap.

[0059] It should be noted that the "axial dimension" mentioned in this application refers to the dimension along the axis of the main shaft 1 (i.e., the groove width); the "radial dimension" refers to the dimension along the diameter of the main shaft 1 (i.e., the groove depth or the radial depth of the groove). The axial dimension of the mounting part 321 is greater than the axial dimension of the through part 322, which means that the groove width of the mounting part 321 is greater than the groove width of the through part 322, thereby forming a stepped surface in the axial direction. This stepped surface can serve as an axial limiting surface for the support member 412, preventing the support member 412 from dislodging from the through part 322. The radial dimension of the mounting part 321 is greater than the radial dimension of the support member 412, which means that the distance from the bottom of the groove to the limiting sidewall 323 is greater than the thickness of the support member 412 in that direction, thereby reserving space for radial movement.

[0060] Example 4: like Figure 3 As shown, based on Embodiment 1, the elastic element 413 is an elastic metal sheet. The elastic metal sheet is inclined in the circumferential direction relative to the radial direction of the gas seal cover 3. One end of the elastic metal sheet is fixed to the outer side of the support member 412, and the other end is pressed against the inner wall of the mounting part 321.

[0061] In the above technical solution, the elastic element 413 is an inclined elastic metal sheet, whose inclination direction relative to the radial direction can be clockwise or counterclockwise along the circumference. When the support element 412 is pushed outward by the main shaft 1, the elastic metal sheet bends and deforms, storing elastic potential energy; when the radial runout of the main shaft 1 decreases, the elastic metal sheet releases potential energy, pushing the support element 412 to return to the limiting sidewall 323 radially inward. The inclination angle of the elastic metal sheet can be designed to match the required radial return force and circumferential preload. Typically, the inclination angle (the angle between the length direction of the elastic metal sheet and the radial direction) can be set to 15° to 45°.

[0062] It should be noted that the "elastic metal sheet" refers to a thin metal sheet with a certain elastic modulus. Commonly used materials include stainless steel, spring steel, beryllium bronze, and phosphor bronze. Its thickness and width are determined according to the required elastic force. "Inclined in the radial and circumferential directions relative to the gas seal cover 3" means that the main extension direction of the elastic metal sheet is neither parallel to the radial direction nor parallel to the circumferential direction, but is somewhere in between. One end is fixed to the outer side of the support member 412, and the other end abuts against the inner wall of the mounting part 321 (usually the bottom wall or side wall of the mounting part 321, depending on the geometry of the mounting groove 32). Multiple elastic metal sheets can be arranged along the axial or circumferential direction of the support member 412 to provide uniform elastic support.

[0063] It is understood that, in one embodiment, multiple elastic metal sheets are fixed to the outer side of each support member 412, and the elastic metal sheets on each support member 412 have the same inclination direction. Preferably, the gas seal cover 3 is composed of multiple cover units, which are sequentially spliced ​​along the circumference. Adjacent cover units are fixed together by connectors, and the mounting grooves 32 of the multiple cover units are sequentially connected to form a complete annular groove.

[0064] In the above technical solution, the split structure of multiple sealing units facilitates processing and assembly. Before assembling the sealing units, operators can pre-install each sealing unit 41 into the mounting groove 32 of each sealing unit from the splicing surface. Since the multiple elastic metal pieces on each support 412 are tilted in the same direction, during installation, the support 412 can be directly inserted into the mounting groove 32 from one side according to this tilt direction, without pressing the elastic element 413, making installation convenient. Compared with the integral gas seal cover 3, this solution reduces processing difficulty and improves assembly efficiency. At the same time, the split structure also makes it easier to replace only a part of the sealing unit during later maintenance, reducing maintenance costs.

[0065] It should be noted that the "sealing unit" refers to dividing the gas seal cap 3 circumferentially into several independent modules, each module having an arc-shaped mounting groove 32. The "connector" between adjacent sealing units can be common fastening elements such as bolts, pins, clips, or locating pins. "Pre-installing the sealing unit 41 from the splicing surface" means using the open end faces (i.e., splicing surfaces) at both ends of the sealing unit to slide the sealing unit 41 circumferentially into the mounting groove 32, avoiding the difficulty of inserting multiple sealing units 41 into the overall annular groove. The same tilt direction of the elastic metal sheets further simplifies the orientation determination during the insertion process, which is especially suitable for automated assembly lines.

[0066] It is understood that in another embodiment, two elastic metal sheets are fixed to the outer side of each support 412, and the two elastic metal sheets on the same support 412 have opposite tilt directions.

[0067] It is understood that in another embodiment, a plurality of the elastic metal sheets are fixed to the outer side of each support 412, and the tilt direction of the elastic metal sheets on each support 412 is random.

[0068] Example 5: like Figures 5 to 7As shown, based on Embodiment 1, it also includes multiple adjusting plates 5 with various thickness specifications. The adjusting plate 5 includes an operating part 51 and a clamping part 52. The mounting groove 32 is provided with an adjusting groove 33 in the axial direction. Each sealing unit 41 is provided with at least one adjusting groove 33. The adjusting groove 33 connects the internal space of the mounting groove 32 with the external space of the oil guide basin body 2. Multiple adjusting plates 5 are selectively inserted into the mounting groove 32 through the adjusting groove 33. The support member 412 and the limiting sidewall 323 radially clamp the clamping part 52. The operating part 51 is located outside the oil guide basin body 2. The axial cross-sectional dimension of the clamping part 52 is smaller than the axial cross-sectional dimension of the adjusting groove 33, so that the clamping part 52 can be inserted into the mounting groove 32 through the adjusting groove 33, or the clamping part 52 can be disengaged from the adjusting groove 33 and the mounting groove 32.

[0069] In the above technical solution, by setting an adjustment groove 33 communicating with the outside in the axial direction of the mounting groove 32, and inserting the clamping part 52 of the adjustment piece 5 between the support member 412 and the limiting sidewall 323, the on-site adjustment of the sealing gap is achieved. Specifically, the limiting sidewall 323 is located on the side of the mounting groove 32 closer to the main shaft 1, and the support member 412 abuts against the limiting sidewall 323 under the action of the elastic member 413. When the clamping part 52 of the adjustment piece 5 is inserted between the two, the support member 412 and the limiting sidewall 323 are no longer in direct contact, but are indirectly transmitted through the clamping part 52. The support member 412 is forced to move radially outward by a distance equal to the thickness of the clamping part 52, thereby driving the sealing member 411 away from the main shaft 1 and increasing the initial gap. Adjustment pieces 5 of different thicknesses correspond to different radial displacements. Users can select one or more pieces to be used in combination according to the actual diameter, roundness error or sealing requirements of the main shaft 1 to achieve precise adjustment. After adjustment, the support 412, under the thrust of the elastic element 413, clamps the clamping part 52 together with the limiting sidewall 323, preventing the adjusting plate 5 from falling off or moving. The operating part 51 is always located outside the oil guide basin body 2, facilitating the insertion, removal, or replacement of the adjusting plate 5 at any time without disassembling the air seal cover 3 or air seal ring 4. In specific use, a sealing unit 41 with an inner diameter slightly smaller than the actual diameter of the spindle can be selected, and a suitable adjusting plate 5 can be selected to compensate for the radial clearance, ensuring that the initial clearance between the sealing element 411 and the spindle 1 meets the design requirements after installation. If the clearance increases due to wear after long-term operation, a thinner adjusting plate 5 can be reinserted for dynamic compensation to restore the sealing performance. The advantages of this solution are: the initial gap can be precisely adjusted on-site according to the actual size of the spindle and the sealing requirements, without disassembling the air seal ring 4, making the operation simple and the adjustment accuracy high; one sealing unit 41 can be equipped with one or more adjustment grooves 33 (preferably two) to achieve multi-position support adjustment, ensuring uniform displacement of the sealing element 411, reducing radial deviation or twisting, and improving fit consistency and long-term sealing reliability; when no adjustment is required, the adjustment plate 5 can be omitted, allowing the support element 412 to be directly limited by the limiting side wall 323 to maintain the maximum preload.

[0070] In particular, because this embodiment includes an adjusting plate 5, the sealing gap between the seal 411 and the main shaft 1 can be precisely controlled according to actual needs. Therefore, while meeting the sealing requirements, it is unnecessary to install multiple air seal rings 4 in the axial direction, thereby significantly simplifying the sealing structure and reducing manufacturing costs and assembly difficulty. Furthermore, when the sealing effect declines after long-term operation, there is no need to disassemble the air seal cover 3 or replace the air seal rings 4; simply increasing or decreasing the thickness or number of the adjusting plate 5 is sufficient to quickly restore the ideal sealing performance, greatly improving maintenance convenience and economy.

[0071] Preferably, to facilitate the insertion of the clamping part 52 of the adjusting plate 5, a guide slope or chamfer can be provided on the upper end face of the support member 412 to guide the clamping part 52 to smoothly slide into the clamping gap between the support member 412 and the limiting sidewall 323. This guide structure can effectively prevent the clamping part 52 from scraping or getting stuck with the edge of the support member 412 during insertion, reducing the difficulty of operation, and is especially suitable for working conditions where the space is limited or the adjusting plate 5 is thin (e.g., 0.05mm).

[0072] Preferably, the adjusting piece 5 can be made of a magnetic material, so that it can be automatically attracted and positioned by the metal surface of the support member 412 or the limiting sidewall 323 after insertion.

[0073] Preferably, an axially penetrating clearance hole 415 is provided between the support member 412 and the sealing member 411, the axial cross-sectional dimension of the clearance hole 415 being larger than the axial cross-sectional dimension of the clamping part 52.

[0074] In the above technical solution, the clearance hole 415 provides an axial passage for the clamping part 52 of the adjusting piece 5 to pass through. After the adjusting piece 5 is inserted from the adjusting groove 33, the clamping part 52 can further pass through the clearance hole 415 axially, thereby extending into the clamping gap between the support member 412 and the limiting sidewall 323. The design of the clearance hole 415 enables the clamping part 52 of the adjusting piece 5 to accurately reach between the support member 412 and the limiting sidewall 323 without interfering with the sealing member 411. At the same time, since the clearance hole 415 axially penetrates the sealing member 411, both the upper and lower sides (i.e., the two ends axially) of the sealing member 411 form a stable contact surface with the support member 412, making the sealing member 411 more evenly stressed during radial movement and avoiding skewing or local wear due to unilateral stress.

[0075] It should be noted that the "adjusting piece 5" refers to a thin sheet-like element with a standard thickness series. Its material can be stainless steel, brass, or polyester film, with thickness specifications such as 0.05mm, 0.10mm, 0.20mm, and 0.50mm. Users can choose to use one or more pieces in combination as needed. The "operating part 51" is the portion of the adjusting piece 5 located outside the oil guide basin body 2, facilitating handheld or tool-assisted clamping. Its shape can be handle-shaped, ring-shaped, or a flat plate with anti-slip texture. The "clamping part 52" is the portion inserted into the mounting groove 32 and clamped by the support member 412 and the limiting sidewall 323. Its axial cross-sectional dimension (i.e., thickness) is smaller than the axial cross-sectional dimension of the adjusting groove 33 to ensure smooth insertion or removal. The "adjusting groove 33" is a through groove extending axially outward from the mounting groove 32 to the outer surface of the oil guide basin body 2. Its number corresponds to the sealing unit 41, with each sealing unit 41 corresponding to at least one adjusting groove 33. The width (axial dimension) of the adjusting groove 33 is slightly larger than the thickness of the clamping part 52, and the axial depth of the adjusting groove 33 should be sufficient to allow the clamping part 52 to extend to the gap between the support member 412 and the limiting sidewall 323. The "avoidance hole 415" is a through hole that axially penetrates the seal 411, and its axial cross-sectional dimension (i.e., hole diameter or groove width) is larger than the axial cross-sectional dimension of the clamping part 52 so that the clamping part 52 can pass through freely; the shape of the avoidance hole 415 can be a round hole, a square hole, or an oblong hole, and its number corresponds to the position and number of the adjusting groove 33. Through the axial penetration design of the avoidance hole 415, both the upper and lower sides of the seal 411 are in contact with the support member 412, forming a double-sided support, which effectively prevents the seal 411 from tilting during radial movement.

[0076] It is understood that the operation part 51 in the above embodiments is only for the convenience of the user when installing, disassembling or replacing the adjustment piece 5. In another embodiment, the adjustment piece 5 may include a clamping part 52 and no operation part 51, so that the entire adjustment piece 5 is located in the mounting groove 32 and the adjustment groove 33. When it is necessary to replace or disassemble the adjustment piece 5, a special tool is required to clamp it from the adjustment groove 33.

[0077] The above description is merely an embodiment of this application and is not intended to limit the scope of protection of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application. All driving components not described in detail in this application are conventional rotary or linear driving components in the art, capable of achieving rotary and linear drive.

Claims

1. A sealing structure for an air seal cover (3) for a lower oil guide pan of a generator, comprising a main shaft (1), an oil guide pan body (2), and an air seal cover (3), wherein the top of the oil guide pan body (2) is provided with an opening (21), the air seal cover (3) closes the opening (21), and a through hole (31) is provided on the air seal cover (3), through which the main shaft (1) passes vertically, characterized in that, The inner wall of the through hole (31) is provided with a circumferentially extending mounting groove (32). An air seal ring (4) is installed in the mounting groove (32). The air seal ring (4) includes multiple sealing units (41). Each sealing unit (41) includes a sealing element (411), a support element (412), and an elastic element (413). Multiple support elements (412) are sequentially arranged in the mounting groove (32) along the extension direction of the mounting groove (32). The support elements (412) are at least partially located in the mounting groove (32) and have radial displacement space relative to the air seal cover (3). The support elements (412) have a working position close to the main shaft (1) in the mounting groove (32). The working position is limited by the limiting sidewall (323) of the mounting groove (32). The elastic element (413) is connected between the corresponding support (412) and the air seal cover (3) to elastically constrain the support (412) to the working position. The sealing element (411) is fixed to the inner side of the corresponding support (412). At least part of the structure of the sealing element (411) extends radially out of the mounting groove (32) and is set close to the main shaft (1). Two adjacent sealing elements (411) abut against each other in the circumferential direction, and multiple sealing elements (411) are arranged around the outer periphery of the main shaft (1) to achieve the sealing between the air seal ring (4) and the main shaft (1).

2. The sealing structure of the gas seal cover (3) for the lower oil guide pan of a generator according to claim 1, characterized in that, The seal (411) is made of a composite material of graphite and insulating flexible material.

3. The sealing structure of the gas seal cover (3) for the lower oil guide pan of a generator according to claim 1, characterized in that, The mounting groove (32) includes a mounting portion (321) and a through portion (322) that are interconnected. The axial dimension of the mounting portion (321) is greater than the axial dimension of the through portion (322). A support member (412) and an elastic member (413) are disposed in the mounting portion (321). The radial dimension of the mounting portion (321) is greater than the radial dimension of the support member (412) so that the support member (412) has a displacement space in the radial direction of the mounting portion (321). The seal (411) extends to the outside of the main shaft (1) via the through portion (322). The sidewall of the mounting portion (321) near the main shaft (1) forms the limiting sidewall (323).

4. The sealing structure of the gas seal cover (3) for the lower oil guide pan of a generator according to claim 3, characterized in that, The elastic element (413) is an elastic metal sheet. The elastic metal sheet is inclined in the circumferential direction relative to the radial direction of the gas seal cover (3). One end of the elastic metal sheet is fixed to the outer side of the support (412), and the other end is pressed against the inner wall of the mounting part (321).

5. The sealing structure of the gas seal cover (3) for the lower oil guide pan of a generator according to claim 4, characterized in that, Multiple elastic metal sheets are fixed to the outside of each support member (412), and the elastic metal sheets on each support member (412) have the same tilt direction.

6. The sealing structure of the gas seal cover (3) for the lower oil guide pan of a generator according to claim 5, characterized in that, The gas seal cover (3) is composed of multiple sealing cover units, which are spliced ​​together in the circumferential direction. Adjacent sealing cover units are fixed by connectors, and the mounting slots (32) of the multiple sealing cover units are connected in sequence to form a complete annular groove.

7. A sealing structure for an air seal cover (3) for a generator lower oil guide pan according to any one of claims 1 to 6, characterized in that, The support members (412) are spaced apart between two adjacent support members in the circumferential direction.

8. A sealing structure for a gas seal cover (3) for a generator lower oil guide pan according to any one of claims 1 to 6, characterized in that, The air seal cover (3) is provided with multiple mounting grooves (32) spaced apart along the axial direction, and each mounting groove (32) is provided with an air seal ring (4); the inner wall of the sealing element (411) is provided with at least one circumferentially extending dividing groove (414), and the dividing groove (414) divides the inner wall of the sealing element (411) into multiple independent sealing surfaces.

9. A sealing structure for a gas seal cover (3) for a generator lower oil guide pan according to any one of claims 1 to 6, characterized in that, It also includes multiple adjusting plates (5) with various thickness specifications. The adjusting plate (5) includes an operating part (51) and a clamping part (52). The mounting groove (32) is provided with an adjusting groove (33) in the axial direction. A sealing unit (41) is provided with at least one adjusting groove (33). The adjusting groove (33) connects the internal space of the mounting groove (32) with the external space of the oil guide basin body (2). Multiple adjusting plates (5) are selectively inserted into the mounting groove (32) through the adjusting groove (33). The support member (412) and the limiting side wall (323) radially clamp the clamping part (52). The operating part (51) is located outside the oil guide basin body (2). The axial cross-sectional dimension of the clamping part (52) is smaller than the axial cross-sectional dimension of the adjusting groove (33) so that the clamping part (52) can be inserted into the mounting groove (32) through the adjusting groove (33) or the clamping part (52) can be removed from the adjusting groove (33) and the mounting groove (32).

10. The sealing structure of the gas seal cover (3) for the lower oil guide pan of a generator according to claim 9, characterized in that, An axially penetrating clearance hole (415) is provided between the support member (412) and the sealing member (411), and the axial cross-sectional dimension of the clearance hole (415) is larger than the axial cross-sectional dimension of the clamping part (52).

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