Oil groove sealing cover with water drop crossed helical tooth structure

Abstract

The utility model relates to a bearing oil groove cover plate, in particular to an oil groove sealing cover with a water drop crossed helical tooth structure, which comprises an oil groove cover, a gap is formed between the oil groove cover and a rotating shaft, and a sealing structure is formed at the upper and lower gap openings; an annular air supply channel is arranged in the oil groove cover, is communicated to the gap through an air supply hole and conveys air into the gap; an air suction hole is formed in the oil groove cover and extends to an air suction cavity from the gap, and the air suction cavity is connected with an oil mist suction treatment device in a matched mode; a sealing structure is formed between the oil groove cover and the rotating shaft and comprises a protruding structure, and the protruding structure comprises a plurality of protruding units and forms a channel. Air is supplied into the gap of the matching surface to form a stable airtight sealing structure, meanwhile, the air suction structure is used for maintaining the stability of air flow in the gap, a sealing structure is formed to be used for treating oil mist in the air flow, and outward discharge of the oil mist is reduced. The structure is stable and reliable, the sealing performance of the rotating shaft can be kept, meanwhile, the sealing structure can be kept stable, and oil mist is reasonably treated.

Description

Technical Field

[0001] The utility model relates to the technical field of oil groove cover plates for bearings of a hydro-turbine generator set, in particular to an oil groove sealing cover provided with a water droplet cross helical tooth structure. Background Art

[0002] The supporting bearings of the main shaft of the hydro-turbine generator set generally use self-lubricating sliding bearings, and the bearing bushes are immersed in lubricating oil. When the unit is running, on the one hand, the lubricating oil is repeatedly stirred and collided in the oil tank, generating a large number of bubbles, which form oil mist after bursting; on the other hand, the oil film on the bearing bush has a higher temperature locally, and the lubricating oil vaporizes at a higher temperature, also forming oil mist. Therefore, for hydro-turbine generators, the generation of oil mist is inevitable, and as the speed of the unit increases, especially the linear speed of large units is higher, the oil splashes everywhere, generating more oil mist, and the severity increases significantly.

[0003] The oil mist escape phenomenon inside the hydropower unit causes the oil mist to escape from the gap between the generator shaft and the oil tank, generating a negative pressure during the operation of the unit. The circulating oil flow in and out of the oil tank is in a turbulent state. The collision and impact between oil molecules and between the moving and static parts and the oil will cause the circulating oil to vaporize and produce oil mist, which overflows through the narrow gap between the generator shaft and the oil tank cover, resulting in a large amount of lubricating oil and oil mist leakage. In order to seal the oil mist generated in the oil tank, as shown in the prior CN203248722U, the disclosed anti-oil mist device includes an annular sealing cylinder and a flange-shaped sealing outer body, one end of the sealing cylinder is connected to the inner edge of the sealing outer body by bolts, the rotating shaft of the generator passes through the sealing cylinder, a respirator is installed on the sealing outer body, and an oil slinger is installed on the surface of the rotating shaft; an upper chamber and a lower chamber are provided on the inner circumferential surface of the sealing cylinder, sealing teeth are installed between the upper chamber and the lower chamber and in the sealing grooves on both sides, and an oil mist absorption layer corresponding to the oil slinger is installed on the inner edge of the sealing outer body; an automatic oil mist absorption processing device and an air supply device are installed on the sealing outer body, an air inlet interface connected to the air supply device is provided in the upper chamber; an oil mist absorption interface connected to the automatic oil mist absorption processing device is provided in the lower chamber.

[0004] The main shortcomings of this structure are as follows: First, an upper chamber is set on the oil tank cover, and the upper chamber is connected to the air supply device, but each upper chamber is independent, and the gas pressure entering it is determined by its own air supply device, resulting in large pressure fluctuations between the gases in each upper chamber. The pressure difference between the gas in each upper chamber on the gap between the rotating shaft and the sealing cylinder and the sealing ring is large, which makes it difficult to meet the uniformity requirements, reduces the sealing effect, and reduces the service life of the sealing ring. Second, because there is a suitable gap between the front end of the oil tank cover and the rotating shaft, the oil-containing gas in the oil tank will flow upward through the gap, but the sealing structure (sealing ring, sealing teeth) set at the front end of the oil tank cover has a weak sealing effect, and the blocking effect on the oil mist in the oil-containing gas is weak, and the blocking effect is poor, resulting in more oil mist passing into the oil mist treatment device, increasing the processing volume of the oil-containing gas. Third, there are usually more air supply devices and oil mist treatment devices, and there are also more gas pipelines and control lines, which is not convenient for on-site equipment layout.

[0005] Therefore, a more reasonable technical solution should be proposed to solve the technical problems existing in the prior art. Utility Model Content

[0006] In order to overcome at least one of the defects mentioned above, the utility model proposes an oil tank sealing cover provided with a water drop cross bevel tooth structure, wherein gas is input into the space between the rotating shaft and the oil tank sealing cover through an air supply structure to form an air sealing structure, so as to keep the gap between the rotating shaft and the oil tank sealing cover and the pressure of the sealing ring constant to meet the uniformity requirement; and a blocking structure is provided in the gap between the oil tank sealing cover and the rotating shaft to block the oil mist, thereby reducing the backward transmission of the oil mist and improving the treatment effect of the oil mist.

[0007] In order to achieve the above purpose, the sealing cover disclosed in the utility model can adopt the following technical solutions:

[0008] An oil tank sealing cover with a water drop cross helical tooth structure comprises an oil tank cover arranged around a rotating shaft of a generator, a gap is formed between the oil tank cover and the rotating shaft, and a sealing structure is formed at the upper and lower gap openings; an annular air supply channel is arranged in the oil tank cover, the air supply channel is connected to the gap through an air supply hole and transports gas into the gap to form a positive pressure;

[0009] The oil tank cover is also provided with a plurality of air suction holes, the front ports of the air suction holes extend to the gap and the rear ports are correspondingly connected to the air suction cavity, and the air suction cavity is connected to the oil mist treatment device;

[0010] A sealing structure is formed on the sealing surface of the oil tank cover facing the rotating shaft. The sealing structure includes several groups of protrusion structures arranged crosswise along the axial direction. The protrusion structure includes several protrusion units arranged at intervals. Gas gaps are formed between adjacent protrusion units to form channels for oil and gas to pass through.

[0011] The oil tank sealing cover disclosed above introduces gas that performs air sealing into the gap between the rotating shaft and the oil tank cover through the air filling hole provided on the oil tank cover, so that the pressure of the gas on the gap between the rotating shaft and the oil tank cover and the sealing ring is kept constant to meet the uniformity requirement; a water droplet cross-bevel tooth structure is provided on the oil tank cover to improve the blocking effect on oil mist in the oil-containing gas, block and reduce the volume of oil mist entering the oil mist absorption treatment device.

[0012] Furthermore, in the present invention, the protrusion unit can be constructed in a variety of forms, and its structure is not limited to a single one. Here, an optimization is performed and one feasible option is proposed: each protrusion unit is in a teardrop shape and the two ends form a large end and a small end respectively.

[0013] Furthermore, the arrangement and combination of the protrusion units can form a channel to facilitate the passage of oil and gas. The structure of the channel can be set in various forms, which is not limited to a single one. Here, an optimization is made and a feasible option is proposed: each group of protrusion structures includes two rows of protrusion units, and the small ends of the two rows of protrusion units are relatively close and staggered. When such a scheme is adopted, the channel formed between the protrusion units is a curved structure, and when the oil and gas pass through it, it is easy to adhere to the channel wall, so that it condenses and then flows back, reducing the oil loss in the gap.

[0014] Furthermore, when the gas in the gap is sucked outward to form a gas circulation, the gas circulation is realized by connecting the suction channel and the suction cavity. The structure of the suction channel is not limited to a single one. Here, an optimization is made and one of the feasible options is proposed: an annular suction channel is set on the oil tank cover, the suction cavity is connected to the suction channel, and the suction channel is also connected to the oil suction mist treatment device to form a negative pressure. When such a solution is adopted, the gas in multiple suction cavities enters the suction channel and is uniformly transported to the oil suction mist treatment device.

[0015] Furthermore, the structure and arrangement of the air supply hole and the air suction cavity are not limited to a single one. Here, an optimization is made and one of the feasible options is proposed: the air supply hole and the air suction cavity extend toward the gap and tilt downward near the gap. When such a solution is adopted, the direction of the airflow can be guided during the air supply process to promote the airflow to flow in a unified direction; at the same time, the resistance of the oil mist is increased during the air suction process, so that more oil mist in the airflow condenses from the air suction cavity and flows back into the gap.

[0016] Furthermore, the arrangement of the protruding units of the sealing structure is not limited to a single one, and an optimization is made here and one feasible option is proposed: the protruding units of the sealing structure protrude radially toward the rotating shaft and deflect downwardly, and adjacent protruding units are spaced apart along the axial direction of the rotating shaft and an annular groove is formed between adjacent protruding units. When such a solution is adopted, a concave-convex structure similar to a sawtooth is formed between adjacent protruding units.

[0017] Furthermore, in order to form a barrier between the oil tank sealing cover and the inner side of the rotating shaft, an optimization is made here and one of the feasible options is proposed: a turbulence front baffle is provided on the inner side where the oil tank cover and the rotating shaft cooperate. When such a solution is adopted, the turbulence front baffle can block impurities and the like on the inner side.

[0018] Furthermore, the structure of the turbulence front baffle can be constructed in various forms, which are not limited to the only one. Here, an optimization is made and one feasible option is proposed: the turbulence front baffle is in the shape of an arc-shaped thin sheet and is provided with a plurality of through holes. When such a solution is adopted, the turbulence front baffle is bent toward the rotating shaft and forms a curved surface.

[0019] Furthermore, in order to improve the sealing performance between the oil tank cover and the rotating shaft, an optimization is made here and a feasible option is proposed: the gap between the oil tank cover and the rotating shaft is provided with an upper sealing ring and a lower sealing ring. When such a solution is adopted, the upper sealing ring and the lower sealing ring can be O-rings.

[0020] Furthermore, in the present invention, the number of the air-injection holes corresponds to the number of the air-injection cavities, specifically: the air-injection holes correspond to the air-injection cavities one by one. When such a solution is adopted, the air-injection holes and the air-injection cavities can be aligned in the circumferential direction, or the two can be staggered.

[0021] Compared with the prior art, some beneficial effects of the technical solution disclosed in the utility model include:

[0022] The utility model adjusts the mating surface structure of the rotating shaft and the oil tank end cover, supplies air into the gap of the mating surface to form a stable air sealing structure, and also provides an air suction structure to maintain the stability of the airflow in the gap, and forms a sealing structure for the oil mist in the airflow to adhere and reflux, reducing the discharge of oil mist. The structure is stable and reliable, can maintain the sealing performance of the rotating shaft, can also maintain the stability of the sealing structure, and reasonably handle the oil mist. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the embodiments of the utility model, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the utility model and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0024] Figure 1 This is a cross-sectional view of the matching structure of the rotating shaft and the oil tank cover of the utility model;

[0025] Figure 2 for Figure 1 A top view of

[0026] Figure 3 This is a cross-sectional view of the rotating shaft and the oil tank cover of the utility model in the second position;

[0027] Figure 4 This is a cross-sectional view of the rotating shaft and the oil tank cover of the utility model at the third position;

[0028] Figure 5 is a schematic diagram of the sealing structure;

[0029] Figure 6 yes Figure 5 A partial enlarged view of

[0030] Figure 7 Schematic diagram of the turbulence front baffle structure.

[0031] In the above drawings, the meanings of the various marks are as follows: 1. rotating shaft; 2. oil tank cover; 3. air supply channel; 4. air supply device; 5. upper sealing ring; 6. lower sealing ring; 7. air supply hole; 8. sealing structure; 9. raised unit; 10. large end; 11. small end; 12. air suction chamber; 13. oil mist treatment device; 14. air suction channel; 15. sealing teeth; 18. turbulence front baffle; 19-through hole. DETAILED DESCRIPTION

[0032] The present invention will be further explained below in conjunction with the accompanying drawings and specific embodiments.

[0033] In view of the many unreasonable features of the existing oil tank sealing cover structure, optimization is performed here to overcome the defects in the prior art.

[0034] Example

[0035] The present embodiment provides an oil tank sealing cover with a water drop cross helical tooth structure, comprising an oil tank cover 2 arranged around a rotating shaft 1 of a generator, a gap is formed between the oil tank cover 2 and the rotating shaft 1, and a sealing structure 8 is formed at the upper and lower gap openings; an annular air supply channel 3 is arranged in the oil tank cover 2, and the air supply channel 3 is connected to the gap through an air supply hole 7 and transports gas into the gap to form a positive pressure;

[0036] The oil tank cover 2 is also provided with a plurality of air suction holes, the front ports of the air suction holes extend to the gap and the rear ports are correspondingly connected to the air suction cavity 12, and the air suction cavity 12 is connected to the oil mist treatment device 13;

[0037] A sealing structure 8 is formed on the sealing surface of the oil tank cover 2 facing the rotating shaft 1. The sealing structure 8 includes a plurality of groups of protrusion structures cross-arranged along the axial direction. The protrusion structure includes a plurality of protrusion units 9 arranged at intervals. Gas gaps are formed between adjacent protrusion units 9 to form channels for oil and gas to pass through.

[0038] The oil tank sealing cover disclosed in this embodiment passes gas that performs air sealing function into the gap between the rotating shaft 1 and the oil tank cover 2 through the air filling hole 7 provided on the oil tank cover 2, so that the pressure of the gas on the gap and the sealing ring between the rotating shaft 1 and the oil tank cover 2 is kept constant to meet the uniformity requirement; a water droplet cross-helical tooth structure is provided on the oil tank cover 2 to enhance the blocking effect on the oil mist in the oil-containing gas, and to block and reduce the volume of the oil mist entering the oil absorption mist treatment device 13.

[0039] In this embodiment, the protrusion unit 9 can be constructed in various forms, and its structure is not limited to a single one. This embodiment is optimized and adopts one of the feasible options: each protrusion unit 9 is in a teardrop shape and the two ends form a large end 10 and a small end 11 respectively.

[0040] The protrusion units 9 are arranged and combined to form a channel, which is convenient for oil and gas to pass through. The structure of the channel can be set in various forms, which are not limited to the only one. This embodiment optimizes and adopts a feasible option: each group of protrusion structures includes two rows of protrusion units 9, and the small ends 11 of the two rows of protrusion units 9 are relatively close and staggered. When such a scheme is adopted, the channel formed between the protrusion units 9 is a curved structure. When oil and gas pass through it, it is easy to adhere to the channel wall, so that it condenses and then flows back, reducing the oil loss in the gap.

[0041] When the gas in the gap is sucked outward to form a gas cycle, the gas circulation is realized by connecting the suction channel 14 and the suction cavity 12. The structure of the suction channel 14 is not limited to a single one. This embodiment is optimized and adopts one of the feasible options: an annular suction channel 14 is set on the oil tank cover 2, and the suction cavity 12 is connected to the suction channel 14. The suction channel 14 is also connected to the oil mist treatment device 13 to form a negative pressure. When such a solution is adopted, the gas in multiple suction cavities 12 enters the suction channel 14 and is uniformly transported to the oil mist treatment device 13.

[0042] The structure and arrangement of the air-filling hole 7 and the air-inhalation cavity 12 are not limited to a single one. This embodiment optimizes and adopts one of the feasible options: the air-filling hole 7 and the air-inhalation cavity 12 extend toward the gap and tilt downward near the gap. When such a solution is adopted, the direction of the airflow can be guided during the air-filling process to promote the airflow to flow in a unified direction; at the same time, the resistance of the oil mist is increased during the air-inhalation process, so that more oil mist in the airflow condenses from the air-inhalation cavity 12 and flows back into the gap.

[0043] The arrangement form of the protruding unit 9 of the sealing structure 8 is not limited to a single one, and this embodiment is optimized and adopts one of the feasible options: the protruding unit 9 of the sealing structure 8 protrudes radially toward the rotating shaft 1 and deflects downwardly, and adjacent protruding units 9 are spaced apart along the axial direction of the rotating shaft 1 and annular grooves are formed between adjacent protruding units 9. When such a solution is adopted, a concave-convex structure similar to a sawtooth is formed between adjacent protruding units 9.

[0044] In order to form a barrier between the oil tank sealing cover and the inner side of the rotating shaft 1, this embodiment is optimized and adopts one of the feasible options: a turbulence front baffle 18 is provided on the inner side of the oil tank cover 2 and the rotating shaft 1. When such a solution is adopted, the turbulence front baffle 18 can block impurities and the like on the inner side.

[0045] The structure of the turbulence front baffle 18 can be constructed in various forms, which are not limited to the only one. This embodiment optimizes and adopts one of the feasible options: the turbulence front baffle 18 is in the shape of an arc-shaped thin sheet and is provided with a plurality of through holes 19. When such a solution is adopted, the turbulence front baffle 18 bends toward the rotating shaft 1 and forms a curved surface.

[0046] In order to improve the sealing performance between the oil tank cover 2 and the rotating shaft 1, this embodiment is optimized and adopts one of the feasible options: the gap between the oil tank cover 2 and the rotating shaft 1 is provided with an upper sealing ring 5 and a lower sealing ring 6. When such a solution is adopted, the upper sealing ring 5 and the lower sealing ring 6 can be O-rings and sealing teeth 15.

[0047] In this embodiment, the number of the air-injection holes 7 corresponds to the number of the air-injection cavities 12. Specifically, the air-injection holes 7 correspond to the air-injection cavities 12. When such a solution is adopted, the air-injection holes 7 and the air-injection cavities 12 can be aligned in the circumferential direction, or the two can be staggered.

[0048] Here is an example to illustrate:

[0049] The oil tank sealing cover of the generator provided in this embodiment is provided with a water drop cross helical tooth structure, such as Figure 1-4 As shown, it is arranged in cooperation with the rotating shaft 1 of the generator, specifically, it is arranged in cooperation with and around the circumference of the rotating shaft 1 of the generator, and an oil tank cover 2 is arranged in the circumference of the rotating shaft 1, and the oil tank cover 2 covers the lubricating oil tank of the generator to form a closed cover; the oil tank cover 2 forms a sealing surface with the corresponding part of the surface of the rotating shaft 1, and a gap is left between the two, and the oil tank cover 2 cannot block the normal rotation of the rotating shaft 1.

[0050] The oil tank cover 2 of this embodiment is an annular structure, in which an annular air supply channel 3 is arranged. The upper and lower ends of the oil tank cover 2 are respectively provided with an upper sealing ring 5 and a lower sealing ring 6 to seal the gap between the oil tank cover 2 and the rotating shaft 1; the upper sealing ring 5 and the lower sealing ring 6 are usually made of soft materials to form a flexible sealing structure.

[0051] The air supply channel 3 is connected with the air supply device 4. A plurality of air supply holes 7 are axially arranged on the front side of the air supply channel 3 (the side facing the rotating shaft). The air supply holes 7 are connected with the gap between the rotating shaft 1 and the oil tank cover 2. After the air supply device 4 is started, the external gas is transported into the air supply channel 3 by the air supply device 4, and then enters the gap between the rotating shaft 1 and the oil tank cover 2 through the air supply holes 7, thereby playing the role of "air sealing".

[0052] like Figure 5 , 6 As shown, a sealing structure 8 is provided on the sealing surface of the oil tank cover 2, and the sealing structure 8 seals the gap between the rotating shaft 1 and the oil tank cover 2; the sealing structure 8 is composed of a plurality of groups of protrusions 9 arranged in a height direction and arranged crosswise, each protrusion 9 is in the shape of a water drop, one end of which is large as a large end 10 and the other end is small as a small end 11, forming a water drop shape, and there are gaps between adjacent protrusions 9, and the gaps are connected to form a gas channel; each group of water drop-shaped protrusions 9 shown in the figure is formed by two rows of protrusions 9 with large ends 10 outside and small ends 11 inside being regularly arranged, and the upper and lower rows of corresponding water drop-shaped protrusions 9 are arranged in staggered positions. When the sealing structure 8 passes through the gap between the adjacent protrusions 9, the airflow will cross, collide and move therein, thereby sealing the oil-containing gas between the rotating shaft 1 and the oil tank cover 2. When the oil-containing gas passes through the sealing structure 8, the blocking effect on the oil mist in the oil-containing gas can be improved, and the blocked oil mist can be formed into water droplets, which will gather and flow back into the oil tank, thereby greatly reducing the volume of oil mist entering the oil mist absorption treatment device.

[0053] At the gap between the rotating shaft 1 and the oil tank cover 2, corresponding to the air-injection holes 7, a plurality of air suction chambers 12 are provided, and the rear end of the air suction chamber 12 is connected to the oil suction mist treatment device 13. After the oil suction mist treatment device 13 is started, the oil suction mist treatment device 13 generates a suction effect, and the gas that enters the air suction chamber 12 from top to bottom through the gap between the rotating shaft 1 and the oil tank cover 2 through the air-injection holes 7, and the gas that enters the air suction chamber 12 from bottom to top from the oil tank through the lower sealing ring 6 are sucked into the oil suction mist treatment device 13, and the oil mist is separated and purified by the oil suction mist treatment device 13 before being discharged. Usually, an air suction chamber 12 is provided corresponding to each air-injection hole 7, and the air-injection hole 7 and the air suction chamber 12 are in a one-to-one correspondence. The oil suction mist treatment device 13 can use existing equipment, which will not be further introduced here as the prior art. In order to enhance the oil mist suction effect and maintain the stability of the suction action, an annular air suction channel 14 is provided on the oil tank cover 2, and each air suction cavity 12 is connected through the air suction channel 14, and the air suction channel 14 is further connected to the oil mist suction treatment device 13; the air suction channel 14 is provided below the air supply channel 3, forming two annular cavities arranged upper and lower, one for inputting gas inwardly, and the other for sucking and discharging gas outwardly.

[0054] The sealing surface of the oil tank cover 2, i.e., the front end of the air supply hole 7 and the front end of the air suction chamber 13, facing the surface of the rotating shaft 1, is provided with a downwardly inclined structure, which can effectively reduce the resistance to inward replenishment and outward air suction when the rotating shaft 1 rotates, and the gas flows more smoothly, producing a better sealing effect. The sealing portion of the oil tank cover 2 facing the surface of the rotating shaft 1 is provided with a serrated, downwardly inclined serrated structure of the protrusion 9 of the sealing structure 8. The downwardly inclined (downward in the height direction of the rotating shaft 1) protrusion 9 cooperates with the downwardly inclined structure of the front end of the air supply hole 7 and the front end of the air suction chamber 12, so that the sealing surfaces of the oil tank cover 2 of the utility model corresponding to the contact with the rotating shaft 1 form an overall downwardly inclined matching structure, which can effectively reduce the resistance to air supply and air suction when the rotating shaft 1 rotates, and the gas flows more smoothly, producing a better sealing effect. The lower end of the protrusion 9 is tilted downward, and the curved channel for the oil-containing gas to flow through is formed between adjacent protrusions 9, which is conducive to the oil mist in the oil-containing gas to condense into small oil droplets at the lower end of the protrusion 9, and then gather into large water droplets and automatically flow back downward into the oil tank.

[0055] like Figure 7 As shown, a turbulence front baffle 18 is provided at the lower end of the oil tank cover 2. After installation, the lower end of the turbulence front baffle 18 usually extends into the oil in the oil tank, or its lower end is slightly higher than the liquid level of the oil. A plurality of through holes 19 are provided on the sheet-like turbulence front baffle 18 to facilitate the passage of oil-containing gas; the turbulence front baffle 18 can prevent the oil in the oil tank from being violently stirred due to the instability of the rotating shaft during operation, causing the oil to directly reach the position of the lower sealing ring 6, thereby allowing the oil to flow stably and reducing the generation of oil mist.

[0056] The above are the implementation methods listed in this embodiment, but this embodiment is not limited to the above optional implementation methods. Those skilled in the art can arbitrarily combine the above methods to obtain other various implementation methods. Anyone can derive other various implementation methods under the inspiration of this embodiment. The above specific implementation methods should not be understood as limiting the protection scope of this embodiment. The protection scope of this embodiment should be based on the definition in the claims.

Claims

1. An oil tank sealing cover with a water drop cross helical tooth structure, comprising an oil tank cover (2) arranged around a rotating shaft (1) of a generator, a gap being formed between the oil tank cover (2) and the rotating shaft (1) and a sealing structure being formed at upper and lower gap openings; characterized in that: An annular air supply channel (3) is provided in the oil tank cover (2), and the air supply channel (3) is connected to the gap through the air supply hole (7) and transports gas into the gap to form a positive pressure; The oil tank cover (2) is also provided with a plurality of air suction holes, the front ports of the air suction holes extend to the gap and the rear ports are correspondingly connected to the air suction cavity (14), and the air suction cavity (14) is connected to the oil mist treatment device (13); A sealing structure (8) is formed on the sealing surface of the oil tank cover (2) facing the rotating shaft. The sealing structure (8) includes a plurality of groups of protrusion structures arranged crosswise along the axial direction. The protrusion structure includes a plurality of protrusion units (9) arranged at intervals. Gas gaps are formed between adjacent protrusion units (9) to form a channel for oil and gas to pass through.

2. The oil tank sealing cover with a water drop cross helical tooth structure according to claim 1, characterized in that: Two ends of each protruding unit (9) form a large end (10) and a small end (11) respectively.

3. The oil tank sealing cover with a water drop cross helical tooth structure according to claim 2, characterized in that: Each group of protrusion structures comprises two rows of protrusion units (9), and the small ends (11) of the two rows of protrusion units (9) are relatively close and staggered.

4. The oil tank sealing cover with a water drop cross helical tooth structure according to any one of claims 1 to 3, characterized in that: An annular air suction channel (12) is provided on the oil tank cover (2), the air suction chamber (14) is connected to the air suction channel (12), and the air suction channel (12) is also connected to the oil suction mist treatment device (13) to form a negative pressure.

5. The oil tank sealing cover with a water drop cross helical tooth structure according to claim 4, characterized in that: The air supply hole (7) and the air suction cavity (14) extend toward the gap and are tilted and deflected downward near the gap.

6. The oil tank sealing cover with a water drop cross helical tooth structure according to any one of claims 1 to 3, characterized in that: The protruding unit (9) of the sealing structure (8) protrudes radially toward the rotating shaft and tilts downward, and adjacent protruding units (9) are spaced apart along the axial direction of the rotating shaft, and annular grooves are formed between adjacent protruding units (9).

7. The oil tank sealing cover with a water drop cross helical tooth structure according to any one of claims 1 to 3, characterized in that: A turbulence front baffle (18) is arranged on the inner side surface of the oil tank cover (2) that cooperates with the rotating shaft.

8. The oil tank sealing cover with a water drop cross helical tooth structure according to claim 7, characterized in that: The turbulence front baffle (18) is in the shape of an arc-shaped thin sheet and is provided with a plurality of through holes (19).

9. The oil tank sealing cover with a water drop cross helical tooth structure according to any one of claims 1 to 3, characterized in that: An upper sealing ring and a lower sealing ring are provided in the gap between the oil tank cover (2) and the rotating shaft.

10. The oil tank sealing cover with a water drop cross helical tooth structure according to any one of claims 1 to 3, characterized in that: The air replenishing holes (7) correspond to the air suction cavities (14) one by one.

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