Seal assembly, gear box and wind turbine generator system

Abstract

This disclosure relates to a sealing assembly, a gearbox, and a wind turbine generator set. The gearbox includes a through cover, a shaft, and a sealing disc. The through cover has a through hole that penetrates both the inner and outer surfaces of the through cover. The shaft portion passes through the through hole. The sealing disc is sleeved on the shaft, connected to the outer surface of the through cover, and forming an oil collection space with the through cover. The sealing disc has an oil return port communicating with the oil collection space. The technical solution provided by this disclosure can improve the sealing effect and reduce oil leakage.

Description

Technical Field

[0001] This disclosure relates to the technical field of wind power equipment, and particularly to a sealing assembly, gearbox, and wind turbine generator set. Background Technology

[0002] Wind turbine generators are typically equipped with gearboxes to increase the low speed of the wind turbine to the high speed required by the generator, thereby achieving an efficient conversion of wind energy into electrical energy.

[0003] Existing gearboxes typically have a sealing element between the high-speed shaft and the through hole of the cover to seal the gap between them. However, with long-term operation, high temperature, vibration, or oil corrosion, the sealing element will gradually fail, leading to problems such as lubricating oil leakage and oil spillage. Utility Model Content

[0004] The purpose of this disclosure is to provide a sealing assembly, gearbox, and wind turbine generator set that can improve sealing performance and reduce oil leakage.

[0005] According to one aspect of this disclosure, a gearbox is provided, the gearbox comprising:

[0006] A through cover having a through hole that penetrates the inner and outer surfaces of the through cover;

[0007] A shaft, the portion of which passes through the through hole;

[0008] A sealing disc is sleeved on the shaft. The sealing disc is connected to the outer surface of the through cover and forms an oil collection space with the through cover. The sealing disc is provided with an oil return port that communicates with the oil collection space.

[0009] The technical solution disclosed herein involves installing a sealing disc on the outer surface of the gearbox's transparent cover and fitting the sealing disc onto the shaft. This allows lubricating oil inside the gearbox to leak through the gap between the through-hole and the shaft, enabling the leaked oil to be collected in the oil collection space. This prevents lubricating oil from splashing everywhere and reduces the cost of manual cleaning and maintenance. Furthermore, the gearbox can be equipped with a pipe connecting the oil return port to the inside of the gearbox, allowing leaked oil to re-enter the gearbox through the oil collection space and the oil return port for reuse, reducing the frequency of gearbox lubrication.

[0010] Optionally, the sealing disc has a through hole, and the sealing disc is sleeved on the shaft through the through hole; the oil return port is located below the through hole.

[0011] The above solution can control the oil in the oil collection space below the through hole, thereby preventing oil from leaking out through the through hole or from causing long-term immersion and corrosion to the sealing element at the through hole.

[0012] Optionally, the outer surface of the transparent cover is provided with a connection hole; the side of the sealing disc adjacent to the transparent cover is provided with a skirt, and the skirt is connected to the connection hole by fasteners.

[0013] The above solution facilitates installation and operation, improves the installation stability of the sealing disc and the cover, and ensures stable operation of the equipment.

[0014] Optionally, the sealing disc further includes a side portion and an end portion, wherein the side portion is arranged around the axis of the shaft; the end portion and the skirt are located at opposite ends of the side portion along the axis of the shaft, the end portion surrounds to form the through hole, and the side portion, the end portion and the through cover surround to form an oil collection space.

[0015] The above solution increases the volume of the oil collection space by utilizing the side portion extending along the shaft's axis, thereby increasing the oil capacity. Simultaneously, the side portion extending along the shaft's axis also increases the distance between the through-hole and the main hole, reducing the likelihood of oil leaking from the through-hole splashing into the main hole and being exposed through it. In other words, it increases the likelihood of oil leaking from the through-hole entering the oil collection space, thus reducing the probability of oil leakage.

[0016] Optionally, the oil return port is located at the bottom end of the side surface.

[0017] The above solution allows all oil in the oil collection space to flow out through the return port, reducing oil retention within the oil collection space. Simultaneously, the pipe can be installed along the thickness of the sealing disc, reducing the axial length of the entire structure formed by the sealing disc and the pipe, thus preventing interference between the pipe and the shaft or other axial components.

[0018] Optionally, a first sealing element is held between the sealing disc and the outer surface of the transparent cover, the first sealing element being disposed around the axis of the shaft.

[0019] The above solution further reduces the possibility of oil leakage by sealing the gap between the first sealing element disc and the outer surface of the cover.

[0020] Optionally, a second sealing element is provided on the inner wall surface of the through hole of the sealing disc, and the second sealing element is arranged around the axis of the shaft.

[0021] The above solution prevents oil leakage from the oil collection space by the second sealing element, while also preventing external dust from entering, thus ensuring the quality of the oil in the oil collection space for recycling.

[0022] Optionally, the sealing disc is composed of at least two disc segments joined together, with the joint surfaces of two adjacent disc segments spaced apart around the axis of the through hole of the sealing disc.

[0023] With the above solution, the sealing disc can be fitted onto the shaft in a splicing manner, thus eliminating the need to disassemble the components connected to the shaft, which facilitates installation and subsequent maintenance.

[0024] Optionally, the sealing disc includes a first disc segment and a second disc segment, wherein the two splicing surfaces of the first disc segment and the second disc segment are coplanar and pass through the through-hole axis of the sealing disc.

[0025] The above solution can reduce the number of installations and facilitate the sealing installation process.

[0026] Optionally, the oil return port is connected to the inside of the gearbox via a pipe.

[0027] The above solution allows leaked oil to re-enter the gearbox through the oil collection space and return port for reuse, reducing the frequency of oil replenishment to the gearbox.

[0028] According to another aspect of this disclosure, a wind turbine generator set is provided, the wind turbine generator set including at least a main shaft, a generator and the aforementioned gearbox, the main shaft being connected to the generator via the gearbox.

[0029] According to another aspect of this disclosure, a sealing assembly includes a sealing disc, a first sealing element, and a second sealing element, wherein the sealing disc is formed by splicing at least two disc segments, the sealing disc has a skirt, a side portion, and an end portion, the skirt and the end portion are located at opposite ends of the side portion, the end portion surrounds a through hole, and the bottom end of the end portion is provided with an oil return port; the first sealing element is disposed on the side of the skirt away from the side portion, and the second sealing element is disposed on the inner wall surface of the through hole. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of this disclosure, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 A perspective view of a portion of the structure of a gearbox according to an embodiment of the present disclosure is shown;

[0032] Figure 2 A partial cross-sectional schematic diagram of a gearbox structure according to an embodiment of the present disclosure is shown;

[0033] Figure 3 A schematic diagram of a first angle of a sealing disc according to an embodiment of the present disclosure is shown;

[0034] Figure 4 A second angle schematic diagram of a sealing disc according to an embodiment of the present disclosure is shown;

[0035] Figure 5 An exploded view of a portion of the structure of a gearbox according to an embodiment of the present disclosure is shown;

[0036] Explanation of reference numerals in the attached figures:

[0037] 100. Through cover; 110. Through hole; 120. Connecting hole;

[0038] 200, shaft;

[0039] 300. Sealing disc; 301. Oil return port; 302. Through hole; 303. Skirt; 304. Side surface; 305. End face; 310. First disc section; 320. Second disc section;

[0040] 400. Oil collection space;

[0041] 500. First sealing element;

[0042] 600. Second sealing element. Detailed Implementation

[0043] In the energy conversion system of a wind turbine generator, the gearbox plays a crucial role. Like a highly efficient "speed amplifier," it precisely boosts the low-speed mechanical energy generated by the wind turbine after capturing wind energy to the high speed required for generator operation, thus achieving efficient conversion of wind energy into electrical energy. It is one of the core components ensuring the stable operation of the unit.

[0044] However, the sealing problem between the high-speed shaft and the through-hole of the gearbox has always been a major challenge in the industry during long-term operation. Currently, the industry generally uses sealing elements at this gap to prevent the leakage of lubricating oil inside the gearbox. However, under the long-term, high-intensity operating environment of the unit, the sealing elements will be continuously corroded by various factors: the friction generated by the continuous rotation of the high-speed shaft will generate a lot of heat, causing the sealing elements to age faster at high temperatures; the unavoidable vibration during unit operation will gradually reduce the fit between the sealing elements and the shaft and through-hole; at the same time, the chemical properties of the lubricating oil itself will also have a certain corrosive effect on the sealing elements.

[0045] These factors combined make sealing elements highly susceptible to gradual failure, leading to a series of problems. Firstly, lubricating oil leaks from the gaps where the seals fail, reducing the oil level inside the gearbox. To ensure proper gearbox lubrication, regular replenishment of lubricating oil is necessary, increasing lubricating oil consumption costs and impacting the unit's power generation efficiency due to downtime required for replenishment. Secondly, the high-speed rotating shaft flings leaked lubricating oil outwards, which adheres to various components of the unit, affecting cleanliness and potentially polluting the surrounding environment. Regular cleaning by staff further increases maintenance costs and workload, causing significant inconvenience to the stable operation of the unit.

[0046] To address the aforementioned problems, this disclosure proposes an innovative solution: installing a specially designed sealing component on the outer surface of the gearbox cover. This sealing component cleverly encloses a sealed oil collection space between itself and the cover, effectively intercepting and collecting the lubricating oil ejected from the high-speed shaft.

[0047] Specifically, when the sealing element fails and the lubricating oil is thrown out by the high-speed shaft, the sealing assembly acts as a sturdy "barrier" to block the lubricating oil in the oil collection space, preventing the lubricating oil from splashing everywhere. This greatly reduces pollution to the equipment and the environment, reduces the frequency and difficulty of manual cleaning, and saves on labor maintenance costs.

[0048] More importantly, the lubricating oil collected in the oil collection space is not useless. This disclosure also includes a corresponding oil return device that can return the collected lubricating oil to the gearbox. After simple filtration, this recovered lubricating oil can be reused in the gearbox's lubrication process, achieving the recycling of lubricating oil. This not only reduces the frequency of adding new lubricating oil to the gearbox and lowers the procurement cost of lubricating oil, but also improves resource utilization efficiency, aligning with the development concept of energy conservation and environmental protection.

[0049] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of this disclosure, but not all embodiments.

[0050] like Figures 1 to 4As shown, this disclosure provides a gearbox that may include a housing, a cover 100, and a shaft 200. The housing and the cover 100 together form a space for accommodating gear transmission components. The cover 100 has a through-hole 110 that penetrates both its inner and outer surfaces. The shaft 200 partially passes through the through-hole 110 for connecting external components. It should be noted that the side of the cover 100 adjacent to the space enclosed by the housing and the cover 100 is the inner surface of the cover 100, and the side facing away is the outer surface of the cover 100.

[0051] For example, the cover 100 can be an integral structure of the housing, serving as part of the housing body. Alternatively, the cover 100 can be designed independently from the housing body and then assembled together. Of course, the cover 100 can also be composed of multiple parts assembled together or be an integral structure. The shaft 200 can be a high-speed shaft of the gearbox, or it can be a low-speed shaft of the gearbox. Considering that the high-speed shaft rotates at a higher speed and is more prone to leakage, the shaft 200 is preferably a high-speed shaft.

[0052] The gearbox may also include a sealing disc 300, which is fitted onto the shaft 200. The sealing disc 300 is connected to the outer surface of the cover 100, meaning that the sealing disc 300 is located outside the space enclosed by the gearbox and the cover 100. The sealing disc 300 and the cover 100 together form an oil collecting space 400. Thus, when lubricating oil inside the gearbox leaks through the gap between the through hole 110 and the shaft 200, the leaked oil can enter the oil collecting space 400 and be collected, thereby preventing the possibility of lubricating oil splashing everywhere and reducing the cost of manual cleaning and maintenance.

[0053] In some embodiments, a sealing element may be provided between the through hole 110 and the shaft 200 to serve as a first-line sealing protection, reducing oil leakage from the gearbox. In the event of accidental leakage, the oil is then collected through the oil collection space 400.

[0054] In some other embodiments, there may be no sealing element between the through hole 110 and the shaft 200, and oil leakage may be prevented only by the oil collection space 400.

[0055] Furthermore, the sealing disc 300 is provided with an oil return port 301, which is connected to the oil collection space 400, so that oil in the oil collection space 400 can be collected through the oil return port 301.

[0056] For example, the gearbox can be equipped with a pipe so that the oil return port 301 is connected to the inside of the gearbox, allowing leaked oil to re-enter the gearbox through the oil collection space 400 and the oil return port 301 for reuse, reducing the frequency of oil replenishment. For instance, a pump can be added to draw oil from the oil collection space 400 through the oil return port 301 and pump it into the gearbox. Alternatively, the oil return port 301 can be manually opened to collect and process the oil in the oil collection space 400.

[0057] Specifically, such as Figures 2 to 4 As shown, the sealing disc 300 has a through hole 302, and the sealing disc 300 is sleeved on the shaft 200 through the through hole 302. The oil return port 301 is located below the through hole 302. In this way, the oil in the oil collection space 400 can be controlled below the through hole 302, thereby preventing oil from leaking out through the through hole 302 or from long-term immersion and corrosion of the sealing element at the through hole 302.

[0058] Regarding the specific connection method between the sealing disc 300 and the through cover 100, in some embodiments, the outer surface of the through cover 100 may be provided with a connection hole 120. The side of the sealing disc 300 adjacent to the through cover 100 is provided with a skirt 303, and the skirt 303 is connected to the connection hole 120 by fasteners.

[0059] For example, there may be multiple connection holes 120 arranged in a ring array around the shaft 200. Correspondingly, the sealing disc 300 is connected to the multiple connection holes 120 by multiple fasteners passing through the skirt 303, thereby ensuring the installation stability of the sealing disc 300.

[0060] In some other embodiments, the sealing disc 300 may also be connected to the cover 100 by welding, bonding or snap-fitting.

[0061] In some embodiments, the sealing disc 300 may further include a side portion 304 and an end portion 305, wherein the side portion 304 is disposed around the axis of the shaft 200, the end portion 305 and the skirt 303 are located at opposite ends of the side portion 304 along the axis of the shaft 200, the end portion 305 surrounds the through hole 302, and the side portion 304, the end portion 305 and the cover 100 surround to form the oil collection space 400, thereby increasing the volume of the oil collection space 400 by utilizing the side portion 304 extending along the axial direction of the shaft 200, and increasing the oil capacity. At the same time, the side portion 304 extending along the axial direction of the shaft 200 can also increase the distance between the through hole 110 and the through hole 302, reducing the possibility of oil leaking from the through hole 110 splashing into the through hole 302 and being exposed through the through hole 302, or in other words, increasing the possibility of oil leaking from the through hole 110 entering the oil collection space 400, and reducing the probability of oil leakage.

[0062] For example, the skirt 303 may be annular, and the skirt 303 may be arranged around the axis 200. There may also be multiple skirts 303, which are spaced apart circumferentially along the side portion 304.

[0063] Correspondingly, the oil return port 301 is located at the bottom of the side portion 304, so that all the oil in the oil collection space 400 can flow out through the oil return port 301, reducing the amount of oil remaining in the oil collection space 400. At the same time, the pipe can be installed in the thickness direction of the sealing disc 300, reducing the axial length of the whole formed by the sealing disc 300 and the pipe, and avoiding interference of the pipe with the shaft 200 or other axial components.

[0064] Considering that oil in the oil collection space 400 may leak from the outer surface of the sealing disc 300 and the cover 100, in some embodiments, a first sealing element 500 may be clamped between the outer surface of the sealing disc 300 and the cover 100. The first sealing element 500 is arranged around the axis of the shaft 200, thereby sealing the gap between the outer surface of the sealing disc 300 and the cover 100 by the first sealing element 500, further reducing the possibility of oil leakage.

[0065] For example, the first sealing element 500 may be a sealing ring or felt. A receiving groove may be provided on the side of the skirt 303 away from the side portion 304, or on the side of the side portion 304 away from the end portion 305, or at the included angle of the side portion 304 away from the end portion 305, for mounting the first sealing element 500.

[0066] Meanwhile, in order to prevent oil in the oil collection space 400 from leaking out between the inner wall of the shaft 200 and the through hole 302, in some embodiments, the inner wall of the through hole 302 of the sealing disc 300 is provided with a second sealing element 600. The second sealing element 600 is arranged around the axis of the shaft 200, so that the second sealing element 600 blocks the oil in the oil collection space 400 from leaking out, and at the same time blocks external dust from entering, ensuring the quality of the oil in the oil collection space 400 so as to facilitate recycling.

[0067] For example, the second sealing element 600 may be a sealing ring or felt. The inner wall surface of the through hole 302 may also be provided with a mounting groove for mounting the second sealing element 600, thereby limiting the second sealing element 600 and preventing axial movement of the second sealing element 600, which would affect normal use.

[0068] The aforementioned sealing disc 300 can be an integral structure, integrally installed on the cover 100.

[0069] The aforementioned sealing disc 300 can also be a split structure, or the sealing disc 300 can be composed of at least two disc segments spliced ​​together. The splicing surfaces of two adjacent disc segments are spaced apart around the axis of the through hole 302 of the sealing disc 300. In this way, the sealing disc 300 can be sleeved on the shaft 200 by splicing, so that the components connected to the shaft 200 do not need to be disassembled, which facilitates installation and subsequent maintenance.

[0070] For example, the sealing disc 300 may have two, three, or four segments, etc.

[0071] Taking the 300 sealing disc as an example, which has two segments, such as Figures 3 to 5 As shown, the sealing disc 300 may include a first disc segment 310 and a second disc segment 320. The first disc segment 310 and the second disc segment 320 have two joint surfaces, which are coplanar and pass through the axis of the through hole 302 of the sealing disc 300. In this way, the number of discs required for installation can be reduced, and the installation operation of the sealing disc 300 can be facilitated.

[0072] Accordingly, taking the sealing disc 300 as an example where it is composed of a first disc segment 310 and a second disc segment 320, the first disc segment 310 and the second disc segment 320 together form the aforementioned through hole 302, skirt 303, side surface 304, and end surface 305. An oil return port 301 is provided on either the first disc segment 310 or the second disc segment 320.

[0073] According to another aspect of this disclosure, a wind turbine generator set is also provided, which includes at least a main shaft, a generator, and the aforementioned gearbox, wherein the main shaft is connected to the generator via the gearbox.

[0074] It should be noted that the specific structure of the gearbox can be found in the detailed description in the above embodiments, and the generator and main shaft can be found in the prior art, and will not be described again here.

[0075] According to another aspect of this disclosure, a sealing assembly is also provided, comprising a sealing disc 300, a first sealing element 500, and a second sealing element 600. The sealing disc 300 is formed by splicing at least two disc segments. The sealing disc 300 has a skirt 303, a side portion 304, and an end portion 305. The skirt 303 and the end portion 305 are located at opposite ends of the side portion 304. The end portion 305 surrounds and forms a through hole 302. An oil return port 301 is provided at the bottom end of the end portion 305. The first sealing element 500 is disposed on the side of the skirt 303 away from the side portion 304, and the second sealing element 600 is disposed on the inner wall surface of the through hole 302.

[0076] It should be noted that the specific structures of the sealing disc 300, the first sealing element 500, and the second sealing element 600 can be found in the detailed descriptions in the above embodiments, and will not be repeated here.

[0077] The terms "upper" and "lower" used in this disclosure are used to describe the relative positional relationship of the various structures in the accompanying drawings. They are only for the purpose of clarity of description and are not intended to limit the scope of implementation of this disclosure. Changes or adjustments to the relative relationships without substantially altering the technical content should also be considered as part of the scope of implementation of this disclosure.

[0078] It should be noted that, in this disclosure, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0079] Furthermore, in this disclosure, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this disclosure according to the specific circumstances.

[0080] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this disclosure. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0081] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this disclosure, and are not intended to limit them. Although this disclosure has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this disclosure.

Claims

1. A gearbox, characterized in that, The gearbox includes: A through cover (100) having a through hole (110) that penetrates the inner and outer surfaces of the through cover (100); A shaft (200) partially passes through the through hole (110); A sealing disc (300) is sleeved on the shaft (200). The sealing disc (300) is connected to the outer surface of the cover (100) and forms an oil collection space (400) with the cover (100). The sealing disc (300) is provided with an oil return port (301) that communicates with the oil collection space (400).

2. The gearbox according to claim 1, characterized in that, The sealing disc (300) has a through hole (302), and the sealing disc (300) is sleeved on the shaft (200) through the through hole (302); The oil return port (301) is located below the through hole (302).

3. The gearbox according to claim 2, characterized in that, The outer surface of the cover (100) is provided with a connection hole (120); The sealing disc (300) has a skirt (303) on the side adjacent to the transparent cover (100), and the skirt (303) is connected to the connecting hole (120) by fasteners.

4. The gearbox according to claim 3, characterized in that, The sealing disc (300) further includes a side portion (304) and an end portion (305), wherein, The side portion (304) is arranged around the axis of the shaft (200); The end face (305) and the skirt (303) are located at opposite ends of the side face (304) along the axis of the shaft (200). The end face (305) surrounds the through hole (302). The side face (304), the end face (305), and the cover (100) together form an oil collection space (400).

5. The gearbox according to claim 4, characterized in that, The oil return port (301) is located at the bottom end of the side portion (304).

6. The gearbox according to any one of claims 1 to 5, characterized in that, A first sealing element (500) is held between the outer surface of the sealing disc (300) and the cover (100), and the first sealing element (500) is arranged around the axis of the shaft (200).

7. The gearbox according to any one of claims 1 to 5, characterized in that, The inner wall surface of the through hole (302) of the sealing disc (300) is provided with a second sealing element (600), which is arranged around the axis of the shaft (200).

8. The gearbox according to any one of claims 1 to 5, characterized in that, The sealing disc (300) is composed of at least two disc segments spliced ​​together, and the splicing surfaces of two adjacent disc segments are spaced apart around the axis of the through hole (302) of the sealing disc (300).

9. The gearbox according to claim 8, characterized in that, The sealing disc (300) includes a first disc segment (310) and a second disc segment (320), wherein the two splicing surfaces of the first disc segment (310) and the second disc segment (320) are coplanar and pass through the axis of the through hole (302) of the sealing disc (300).

10. The gearbox according to claim 1, characterized in that, The oil return port (301) is connected to the inside of the gearbox via a pipe.

11. A wind turbine generator set, characterized in that, The wind turbine generator set includes at least a main shaft, a generator, and a gearbox as described in any one of claims 1 to 10, wherein the main shaft is connected to the generator via the gearbox.

12. A sealing assembly, characterized in that, The sealing assembly includes a sealing disc (300), a first sealing element (500), and a second sealing element (600), wherein, The sealing disc (300) is composed of at least two disc segments spliced ​​together. The sealing disc (300) has a skirt (303), a side portion (304) and an end portion (305). The skirt (303) and the end portion (305) are located at opposite ends of the side portion (304). The end portion (305) surrounds and forms a through hole (302). The bottom end of the end portion (305) is provided with an oil return port (301). The first sealing element (500) is disposed on the side of the skirt (303) away from the side portion (304), and the second sealing element (600) is disposed on the inner wall surface of the through hole (302).

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