Non-contact zero-leakage combined sealing device for high-speed shaft of wind power gear box

Abstract

The invention relates to the technical field of wind power gear box high-speed shaft sealing, in particular to a wind power gear box high-speed shaft non-contact zero-leakage combined sealing device which is used for sealing a gap between a high-speed shaft in a wind power gear box and a gear box high-speed shaft end cover. The sealing device comprises a sealing sleeve assembly, a centrifugal switch assembly, a magnetic fluid sealing assembly, an overflow valve assembly and an air guide pressure maintaining assembly. The sealing sleeve assembly and the centrifugal switch assembly form clearance sealing, the sealing sleeve assembly, the air guide pressure maintaining assembly and the magnetic fluid sealing assembly form air pressure sealing together, and the magnetic fluid sealing assembly forms magnetic fluid sealing. The high-speed shaft and the outer end cover of the wind power gear box are sealed together through the synergistic effect of gap sealing, air pressure sealing and magnetic fluid sealing. And meanwhile, pressure maintaining is conducted on a pressure maintaining ring cavity in the air guiding and pressure maintaining assembly through the overflow valve assembly, and lubricating oil leaked into the pressure maintaining ring cavity is discharged into the gearbox through the overflow valve assembly.

Description

Technical Field

[0001] This invention relates to the field of high-speed shaft sealing technology for wind turbine gearboxes, specifically to a contactless, zero-leakage combined sealing device for high-speed shafts of wind turbine gearboxes. Background Technology

[0002] Wind power generation is a crucial pathway for my country to achieve peak carbon emissions and carbon neutrality, as well as a green transformation of its energy structure. High-speed shaft seals in wind turbine gearboxes are key components ensuring the stable operation of the gearbox lubrication system. Their sealing reliability directly impacts the power generation safety, system operating efficiency, and environmental friendliness of the wind turbine. Currently, high-speed shaft seals in wind turbine gearboxes commonly employ structural forms such as skeleton oil seals, mechanical seals, and labyrinth seals. However, skeleton oil seals, under complex operating conditions such as high speeds and large temperature differences, are prone to wear and aging of the rubber material, leading to rapid deterioration of sealing performance and requiring frequent replacement, severely impacting equipment operation and maintenance efficiency and economy. While mechanical seals possess certain sealing performance, they have extremely high requirements for installation accuracy, shaft coaxiality, and lubrication conditions. In operating environments characterized by frequent wind turbine start-ups and shutdowns, speed changes, shaft vibrations, and severe temperature fluctuations, they are prone to dry friction, thermal deformation, and even seal failure, making long-term stable operation difficult. Labyrinth seals are widely used due to their simple structure and high-speed resistance, but their sealing ability against splashed lubricating oil and oil mist within the gearbox is limited, making zero leakage difficult and posing a significant leakage risk. Therefore, the reliability of the high-speed shaft seal in wind turbine gearboxes has become a key issue restricting the high-quality development of wind turbine generator sets. Summary of the Invention

[0003] The purpose of this invention is to provide a contactless, zero-leakage combined sealing device for the high-speed shaft of a wind turbine gearbox, which can prevent oil mist leakage inside the gearbox.

[0004] The technical solution of this invention is as follows: a contactless zero-leakage combined sealing device for the high-speed shaft of a wind turbine gearbox, which is installed at the high-speed shaft of the wind turbine gearbox. The high-speed shaft is installed inside the high-speed shaft end cover of the gearbox via a high-speed shaft generator-side bearing. An outer end cover is provided on one side of the high-speed shaft end cover. The end of the high-speed shaft passes through the outer end cover and extends to the outside of the outer end cover. The sealing device is used to seal the gap between the high-speed shaft inside the wind turbine gearbox and the high-speed shaft end cover of the gearbox. The sealing device includes a sealing sleeve assembly, a centrifugal switch assembly, a magnetic fluid sealing assembly, and a gas guiding and pressure maintaining assembly. The sealing sleeve assembly and the centrifugal switch assembly form a gap seal. The sealing sleeve assembly, the gas guiding and pressure maintaining assembly, and the magnetic fluid sealing assembly together form a pneumatic seal. The magnetic fluid sealing assembly forms a magnetic fluid seal. The gap seal, the pneumatic seal, and the magnetic fluid seal work together to seal the gap between the high-speed shaft of the wind turbine gearbox and the outer end cover. The sealing sleeve assembly is located on the outside of the high-speed shaft generator-side bearing. The sealing sleeve assembly includes an oil guide ring and a conical dynamic sealing sleeve. The oil guide ring is located on the outside of the high-speed shaft generator-side bearing and is mounted on the inner wall of the gearbox high-speed shaft end cover. An oil guide gap is provided between the oil guide ring and the high-speed shaft. Several oil guide holes are provided through the oil guide ring. Each oil guide hole communicates with the outside through an oil injection channel on the gearbox high-speed shaft end cover and an oil injection hole on the outer end cover. An oil drain groove is provided on the inner wall of the oil guide ring. The oil drain groove is connected to several oil guide holes; the dynamic sealing sleeve is sleeved on the first shoulder of the high-speed shaft, and the large-diameter end of the dynamic sealing sleeve is located on one side of the oil guide ring; an oil guide ring cover is sleeved on the outside of the dynamic sealing sleeve, the oil guide ring cover is connected to the inner wall of the gearbox high-speed shaft end cover, one side of the oil guide ring cover abuts against the side wall of the oil guide ring, one side of the inner wall of the oil guide ring cover is provided with a conical structure that matches the dynamic sealing sleeve, the other side of the oil guide ring cover is connected to the side wall of the outer end cover, and a centrifugal gap is provided between the inner wall of the oil guide ring cover and the dynamic sealing sleeve; The centrifugal switch assembly is sleeved on the second shoulder of the high-speed shaft and is located between the generator-side bearing of the high-speed shaft and the dynamic sealing sleeve. The centrifugal switch assembly includes a hollow centrifugal sleeve with a T-shaped sealing ring inside. The T-shaped sealing ring includes a sealing part and an abutting part. The sealing part is slidably connected to the side wall of the centrifugal sleeve through a sliding port. One end of the sealing part abuts against the inner wall of the oil guide ring cover. A pre-tightening spring connected to the inner wall of the centrifugal sleeve is provided on the inner diameter side of the abutting part. A centrifugal rotation mechanism is provided on the abutting part. Under the action of centrifugal force, the sealing part of the T-shaped sealing ring is pressed into the interior of the centrifugal sleeve by the centrifugal rotation mechanism. The magnetic fluid sealing assembly is located on one side of the dynamic sealing sleeve. The magnetic fluid sealing assembly includes an inner pole shoe and an outer pole shoe with the same structure. The inner walls of the inner pole shoe and the outer pole shoe are provided with pole teeth. Magnetic fluid is provided at the pole teeth of the inner pole shoe and the outer pole shoe. A permanent magnet ring is connected between the inner pole shoe and the outer pole shoe. The outer walls of the inner pole shoe, the permanent magnet ring, and the outer pole shoe are all connected to the inner wall of the oil guide ring gland. One side of the outer pole shoe is connected to the side wall of the outer end cap. The pressure-maintaining and air-guiding assembly includes a pressure-maintaining ring cavity formed by the inner wall of the oil guide ring cover, the side wall of the dynamic sealing sleeve, the high-speed shaft, and the side wall of the inner pole shoe. The pressure-maintaining ring cavity is connected to a pressure-stabilizing air-guiding channel and a leakage collection cavity opened on the oil guide ring cover. The pressure-stabilizing air-guiding channel is connected to an external air source through a pressurization hole opened on the outer end cover. One end of the leakage collection cavity is connected to an overflow channel located below the high-speed shaft. An overflow valve assembly is installed inside the overflow channel. One end of the overflow channel is connected to the inside of the gearbox through a pressure relief hole opened on the oil guide ring and the generator side bearing of the high-speed shaft. The overflow valve assembly maintains pressure in the pressure-maintaining ring cavity and discharges the lubricating oil leaking into the pressure-maintaining ring cavity into the gearbox through the overflow valve assembly.

[0005] Preferably, a sleeve sealing ring is provided between the dynamic sealing sleeve and the high-speed shaft, the large-diameter end of the dynamic sealing sleeve is connected to the first shoulder of the high-speed shaft, and a sleeve retaining ring is provided at the small-diameter end of the dynamic sealing sleeve; a plurality of spiral grooves are evenly opened on the side wall of the dynamic sealing sleeve.

[0006] Furthermore, a bearing retainer ring is provided on one side of the high-speed shaft generator side bearing, and the bearing retainer ring is located between the high-speed shaft generator side bearing and the oil guide ring. An oil storage groove is provided on the outer wall of the oil guide ring, and the oil storage groove is connected to several oil guide holes.

[0007] Preferably, an oil guide ring sealing ring is provided between the oil guide ring cover and the oil guide ring, and between the oil guide ring cover and the high-speed shaft end cover of the gearbox.

[0008] Furthermore, the centrifugal sleeve includes a mounting ring, with a left collar and a right collar symmetrically arranged on both sides of the mounting ring. The T-shaped sealing ring is fastened to the inside of the centrifugal sleeve by the left collar and the right collar. The left collar abuts against the second shoulder of the high-speed shaft, and a left collar sealing ring is provided between the left collar and the second shoulder. The right collar abuts against the side wall of the dynamic sealing sleeve, and a right collar sealing ring is provided between the right collar and the dynamic sealing sleeve. A sliding port is provided between the left collar and the right collar, and the sealing part of the T-shaped sealing ring extends to the outside of the centrifugal sleeve through the sliding port. The T-shaped sealing ring is composed of several sealing ring segments connected end to end. Each sealing ring segment has a locking part at both ends, and the locking parts at the beginning and end of each sealing ring segment are staggered.

[0009] Furthermore, the centrifugal rotation mechanism includes a left receiving ring and a right receiving ring symmetrically arranged on both sides of the T-shaped sealing ring. Each left receiving ring and the right receiving ring are provided with several mounting bases. Each mounting base is rotatably connected to a centrifugal block via a pin. The centrifugal block has a centrifugal part and a contact part at both ends. The weight of the centrifugal part is greater than the weight of the contact part. The contact part and the groove on the abutment part cooperate with each other.

[0010] Preferably, an inner electrode shoe sealing ring and an outer electrode shoe sealing ring are respectively provided between the inner electrode shoe and the outer electrode shoe and the oil guide ring cap.

[0011] Preferably, a gas-guiding sealing ring is provided at the pressure-stabilizing gas-guiding channel and the pressurization hole, and the gas-guiding sealing ring is located on the side wall of the oil guide ring cover.

[0012] Furthermore, the overflow valve assembly includes a valve core, which abuts against the inner wall of one side of the overflow channel to form a conical sealing surface. The valve core has an oil guide hole, and one end of the valve core is connected to a pressure adjusting spring. One end of the pressure adjusting spring is connected to a pressure adjusting screw. The side wall of the pressure adjusting screw abuts against the inner wall of the overflow channel. The pressure adjusting screw adjusts the compression of the pressure adjusting spring to form an overflow pressure at the conical sealing surface formed by the valve core and the overflow channel. An overflow pressure relief hole is provided through the middle of the pressure adjusting screw. When the pressure in the pressure-holding ring cavity is not higher than the overflow pressure of the overflow valve assembly, the overflow valve assembly is in the closed state. Under the action of the pressure regulating spring, the valve core is pressed against the inner wall of the overflow channel, and the valve core separates the leakage collection cavity from the overflow channel to achieve the pressure-holding function. When the pressure in the pressure-holding ring cavity reaches the overflow pressure of the overflow valve assembly, the pressure regulating spring in the overflow channel begins to compress, the valve core separates from the inner wall of the overflow channel, and the leakage collection cavity is connected through the overflow channel, the valve core guide hole, and the overflow pressure relief hole and pressure relief hole.

[0013] The beneficial effects of this invention are as follows: The dynamic sealing sleeve, with its conical cross-section decreasing in size from the inside out, creates a pressure-reducing effect, causing the lubricating oil pressure in the centrifugal gap to gradually decrease in the leakage direction from left to right. Simultaneously, the conical spiral groove, rotating at high speed with the high-speed shaft, generates a pressure difference from right to left, pumping pressure onto the lubricating oil in the centrifugal gap from right to left, further sealing the lubricating oil. Furthermore, the gradually increasing conical cross-section of the dynamic sealing sleeve, as the conical spiral groove rotates at high speed with the high-speed shaft, subjectes the lubricating oil in the centrifugal gap to a significant centrifugal force, creating a centrifugal seal in the opposite direction of leakage. Finally, the gas pressure within the pressure-holding ring cavity also contributes to sealing the lubricating oil in the centrifugal gap. The throttling effect of the conical cross-section, the pumping effect of the spiral groove, the centrifugal effect of the combination of the conical cross-section and the spiral groove, and the gas pressure effect of the pressure-holding ring cavity all work together to achieve a synergistic sealing effect on the lubricating oil in the centrifugal gap. These four combined effects reach pressure balance on the right side of the oil drain groove, ensuring that the lubricating oil from the oil drain groove can only enter the gearbox from its left side, providing auxiliary cooling and lubrication for the bearings and gears inside the gearbox. The magnetic fluid sealing assembly achieves a pressure-holding and sealing effect on the pressure-holding cavity formed by the pressure-holding ring cavity, the pressure-stabilizing gas guide channel, and the leakage collection cavity, fully leveraging the advantage of magnetic fluid in reliably sealing gases. Finally, the overflow valve assembly automatically discharges any leaking lubricating oil into the gearbox, ensuring that the lubricating oil flows through the oil guide gap, the passage gap, and the centrifugal gap during wind turbine power generation, all with gap seals and no mechanical-physical contact. The entire sealing system forms a contactless, zero-leakage, ultra-long-life sealing solution. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 This is a cross-sectional schematic diagram of the installation location of the present invention inside a wind turbine gearbox; Figure 2 This is a cross-sectional schematic diagram showing the invention in use; Figure 3 for Figure 2 A magnified view of a section at point B in the middle; Figure 4 This is a cross-sectional view of the other side of the invention in use. Figure 5 This is a cross-sectional view of the oil guide ring of the present invention; Figure 6 This is a cross-sectional schematic diagram of the sealing sleeve assembly of the present invention; Figure 7 A partial 3D view of the centrifugal switch assembly; Figure 8 This is a partial cross-sectional view of the centrifugal switch assembly when the high-speed shaft is stationary. Figure 9 This is a partial cross-sectional view of the centrifugal switch assembly during high-speed shaft movement. Figure 10 Schematic diagram of a T-shaped sealing ring connector; Figure 11 This is a cross-sectional schematic diagram of the magnetofluid assembly of the present invention; Figure 12 for Figure 4 A magnified view of a section at point C.

[0016] In the diagram: High-speed shaft 1, high-speed shaft generator side bearing 11, first shoulder 12, bearing retaining ring 13, gearbox oil inlet nozzle 14, gearbox oil outlet nozzle 15, second shoulder 16, left collar seal ring 16-1; gearbox high-speed shaft end cover 2, oil injection channel 2-1; outer end cover 3, oil injection hole 3-1; sealing sleeve assembly 4, oil guide ring 41, oil guide hole 41-1, oil drain groove 41-2, oil reservoir 41-3, guide... Oil gap 41-4, dynamic sealing sleeve 42, centrifugal gap 42-1, oil guide ring gland 43, oil guide ring gland sealing ring 43-1, horizontal inner circular surface 43-2, passage gap 43-3, sleeve retaining ring 44, spiral groove 45; Magnetofluid sealing assembly 5, inner pole shoe 51, inner pole shoe sealing ring 51-1, outer pole shoe 52, outer pole shoe sealing ring 52-1, pole tooth 53, permanent magnet ring 54; Gas guiding and pressure maintaining assembly 6, pressure maintaining 61. Ring cavity; 61-1. Pressure holding cavity; 62. Pressure stabilizing air guide channel; 62-1. Pressurizing hole; 63. Leakage collection cavity; 63-1. Pressure relief hole; 63-2. Overflow channel; 64. Overflow valve assembly; 64-1. Valve core; 64-2. Valve core oil guide hole; 64-3. Pressure adjusting spring; 64-4. Pressure adjusting screw; 64-5. Overflow pressure relief hole; 65. Air guide sealing ring; 7. Centrifugal switch assembly; 71. Centrifugal sleeve; 71-1. 71-2 left collar, 71-3 right collar, 71-4 right collar sealing ring, 72 T-shaped sealing ring, 72-1 sealing part, 72-2 abutting part, 72-3 sealing ring petal, 72-4 engaging part, 72-5 slot, 73 pre-tightening spring, 74 centrifugal rotation mechanism, 74-1 left receiving ring, 74-2 right receiving ring, 74-3 mounting base, 75 centrifugal block, 75-1 centrifugal part, 75-2 contact part. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] In the description of this invention, it should be noted that the terms "middle," "upper," "lower," "one side," "one end," "vertical," "horizontal," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention. Furthermore, unless otherwise explicitly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0019] like Figure 1-12 As shown, a contactless zero-leakage combined sealing device for the high-speed shaft of a wind turbine gearbox is provided at the high-speed shaft 1 of the wind turbine gearbox. The high-speed shaft 1 is rotatably connected to the high-speed shaft end cover 2 of the gearbox via a high-speed shaft generator-side bearing 11. An outer end cover 3 is provided on one side of the high-speed shaft end cover 2 of the gearbox. The end of the high-speed shaft 1 passes through the outer end cover 3 and extends to the outside of the outer end cover 3. The sealing device is used to seal the gap between the high-speed shaft 1 and the high-speed shaft end cover 2 of the gearbox. The sealing device includes: a sealing sleeve assembly 4, a magnetic fluid sealing assembly 5 and an air guiding and pressure maintaining assembly 6, a centrifugal switch assembly 7, and an overflow valve assembly 64. Figure 1 Point A in the middle is the installation position of the sealing device described in this embodiment; wherein, the sealing sleeve assembly 4 and the centrifugal switch assembly 7 form a gap seal, the sealing sleeve assembly 4, the air guiding and pressure maintaining assembly 6 and the magnetic fluid sealing assembly 5 together form a pneumatic seal, the magnetic fluid sealing assembly 5 forms a magnetic fluid seal, and the overflow valve assembly 64 serves to maintain pressure and discharge any possible leaked lubricating oil into the gearbox; through the synergistic effect of the gap seal, the pneumatic seal and the magnetic fluid seal, the high-speed shaft of the wind turbine gearbox and the outer end cover are sealed, and at the same time, the overflow valve assembly 64 discharges any possible leaked lubricating oil into the gearbox.

[0020] Specifically, in this embodiment, a zero-leakage combined seal is formed by the sealing sleeve assembly 4, the magnetic fluid sealing assembly 5, the air guiding and pressure maintaining assembly 6, the centrifugal switch assembly 7, and the overflow valve assembly 64. When the wind turbine control system detects that the ambient wind speed reaches the wind turbine's cut-in wind speed, the wind turbine control system will perform self-checks on the electrical system, mechanical system, sensing system, and lubrication system. This patent focuses on the wind turbine gearbox lubrication system, therefore, it only focuses on the gearbox lubrication system and related factors. Other electrical and mechanical systems are common technologies in the field of wind turbine gearbox technology and will not be described in detail. When the wind turbine control system detects that the ambient wind speed reaches the wind turbine's cut-in wind speed, it starts the gearbox lubrication oil pump. The lubricating oil supplied by the pump, with a certain temperature and pressure, is filtered and cooled by the filtration and cooling systems. It then forms two pressurized oil paths through a three-way connector: a gearbox lubrication oil path and a gearbox sealing oil path. The lubricating oil in the gearbox lubrication oil path is controlled to reach the set pressure and flow rate, then enters the gearbox through the gearbox inlet nozzle 14 to cool and lubricate the gears and bearings inside, preventing wear caused by dry friction during startup. Finally, it flows out through the gearbox outlet nozzle 15, returning to the gearbox lubrication oil pump's supply tank to complete the lubrication oil circulation. Simultaneously, the lubricating oil in the gearbox sealing oil path is controlled to reach the set pressure and flow rate, then introduced into the oil filling channel 2-1 through the oil filling hole 3-1 on the outer end cover 3. The lubricating oil then flows through the oil reservoir 41-3 and the guide hole 41-1 into the drain trough 41-2. At this time, because the T-seal ring 72 on the right side of the oil drain groove 41-2 is pressed against the horizontal inner circular surface 43-2 of the oil guide ring cover 43 to play a static sealing role, the lubricating oil in the oil drain groove 41-2 can only flow into the gearbox through the oil guide gap 41-4 on the left side of the oil drain groove 41-2 to play an auxiliary cooling and lubrication role for the high-speed shaft generator side bearing 11.

[0021] In this embodiment, as Figure 1-6As shown, the sealing sleeve assembly 4 is located on the outside of the high-speed shaft generator-side bearing 11. The sealing sleeve assembly 4 includes an oil guide ring 41 and a conical dynamic sealing sleeve 42. The oil guide ring 41 is located on the outside of the high-speed shaft generator-side bearing 11 and is installed on the inner wall of the gearbox high-speed shaft end cover 2. An oil guide gap 41-4 is provided between the oil guide ring 41 and the high-speed shaft 1. Several oil guide holes 41-1 are provided through the oil guide ring 41. Each oil guide hole 41-1 is connected to the outside through an oil injection channel 2-1 opened on the gearbox high-speed shaft end cover 2 and an oil injection hole 3-1 opened on the outer end cover 3. An oil drain groove 41- is provided on the inner wall of the oil guide ring 41. 2. The oil drain groove 41-2 is connected to several oil guide holes 41-1; the dynamic seal sleeve 4 is sleeved on the first shoulder 12 of the high-speed shaft 1, and the large diameter end of the dynamic seal sleeve 42 is located on one side of the oil guide ring 41; an oil guide ring cover 43 is sleeved on the outside of the dynamic seal sleeve 42, the oil guide ring cover 43 is connected to the inner wall of the gearbox high-speed shaft end cover 2, one side of the oil guide ring cover 43 abuts against the side wall of the oil guide ring 41, one side of the inner wall of the oil guide ring cover 43 is provided with a conical structure that matches the dynamic seal sleeve 42, the other side of the oil guide ring cover 43 is connected to the side wall of the outer end cover 3, and a centrifugal gap 42-1 is provided between the inner wall of the oil guide ring cover 43 and the dynamic seal sleeve 42.

[0022] like Figure 1-4 As shown, a sleeve sealing ring is provided between the dynamic sealing sleeve 42 and the high-speed shaft 1. The large-diameter end of the dynamic sealing sleeve 42 is connected to the first shoulder 12 of the high-speed shaft 1, and a sleeve retaining ring 44 is provided at the small-diameter end of the dynamic sealing sleeve 42. Several spiral grooves 45 are evenly opened on the side wall of the dynamic sealing sleeve 42.

[0023] Based on the above embodiments, oil is injected into the oil drain 41-2 through the oil injection hole 3-1, oil injection channel 2-1, and oil guide hole 41-1. The oil inside the oil drain 41-2 flows to the centrifugal gap 42-1 between the dynamic sealing sleeve 42 and the oil guide ring cover 43. When the high-speed shaft 1 drives the dynamic sealing sleeve 42 to rotate at high speed, the oil in the centrifugal gap 42-1 between the dynamic sealing sleeve 42 and the oil guide ring cover 43 forms a sealing pressure opposite to the leakage direction at the centrifugal gap 42-1 under the action of centrifugal force, pumping effect, and throttling resistance. Since the dynamic sealing sleeve 42 has a cross-section that changes from large to small from the inside out, the oil in the centrifugal gap 42-1 forms a sealing pressure opposite to the leakage direction at the centrifugal gap 42-1. The small conical shape of the dynamic sealing sleeve 42 causes the lubricating oil in the centrifugal gap 42-1 to gradually decrease in conical cross-section as it flows to the right, creating a throttling and pressure-reducing effect. This results in a gradual decrease in lubricating oil pressure in the centrifugal gap 42-1 in the leakage direction from left to right. Simultaneously, under pressure, the lubricating oil tends to gradually fill the entire centrifugal gap 42-1 from left to right. Secondly, the conical spiral groove 45 generates a pressure difference from right to left as the high-speed shaft 1 rotates at high speed, generating a pumping pressure from right to left on the lubricating oil in the centrifugal gap 42-1, further sealing the lubricating oil in the centrifugal gap 42-1. Furthermore, because the conical cross-section of the dynamic sealing sleeve 42 gradually increases from right to left, the conical spiral groove 45, during the high-speed rotation of the high-speed shaft 1, causes the lubricating oil in the centrifugal gap 42-1 to experience a significant centrifugal force. Due to the obstruction of the oil guide ring cap 43, the centrifugal effect of the lubricating oil manifests as a centrifugal force opposite to the leakage direction of the centrifugal gap 42-1, achieving a centrifugal sealing effect.

[0024] Among them, a bearing retainer ring 13 is provided on one side of the high-speed shaft generator side bearing 11, and the bearing retainer ring 13 is located between the high-speed self-aligning roller bearing 11 and the oil guide ring 41. An oil storage groove 41-3 is provided on the outer wall of the oil guide ring 41, and the oil storage groove 41-3 is connected to several oil guide holes 41-1. An oil guide ring cover sealing ring 43-1 is provided between the oil guide ring cover 43 and the oil guide ring 41, and between the oil guide ring cover 43 and the high-speed shaft end cover 2 of the gearbox.

[0025] Based on the above embodiments, the high-speed shaft 1 is disposed inside the gearbox, the gearbox outer cover 2 is installed on the gearbox, the gearbox is provided with lubricating oil to ensure the normal operation of the high-speed shaft 1, the lubricating oil inside the gearbox splashes into the gearbox outer cover 2 and leaks through the connection between the high-speed shaft 1 and the outer end cover 3, and the sealing assembly seals the high-speed shaft 1 and the outer end cover 3 to prevent the lubricating oil from leaking from the inside of the gearbox.

[0026] In this embodiment, as Figure 3 and Figure 7-10As shown, the centrifugal switch assembly 7 is sleeved on the second shoulder 16 of the high-speed shaft 1, and the centrifugal switch assembly 7 is located between the generator side bearing 11 of the high-speed shaft and the dynamic sealing sleeve 4. The centrifugal switch assembly 7 includes a hollow centrifugal sleeve 71. A T-shaped sealing ring 72 is provided inside the centrifugal sleeve 71. The T-shaped sealing ring 72 includes a sealing part 72-1 and an abutting part 72-2. The sealing part 72-1 is slidably connected to the side wall of the centrifugal sleeve 71 through a sliding port. One end of the sealing part 72-1 abuts against the inner wall of the oil guide ring cover 43. A pre-tightening spring 73 connected to the inner wall of the centrifugal sleeve 71 is provided on the inner diameter side of the abutting part 72-2. A centrifugal rotation mechanism 74 is provided on the abutting part 72-2. Under the action of centrifugal force, the centrifugal rotation mechanism 74 presses the sealing part 72-1 of the T-shaped sealing ring 72 into the interior of the centrifugal sleeve 71.

[0027] Among them, such as Figure 2 , Figure 7-10 As shown, the centrifugal sleeve 71 includes a mounting ring 71-1. A left collar 71-2 and a right collar 71-3 are symmetrically arranged on both sides of the mounting ring 71-1. The T-shaped sealing ring 72 is fastened inside the centrifugal sleeve 71 by the left collar 71-2 and the right collar 71-3. The left collar 71-2 abuts against the second shoulder 16 of the high-speed shaft 1, and a left collar sealing ring 16-1 is provided between the left collar 71-2 and the second shoulder 16. The right collar 71-3 abuts against the side wall of the dynamic sealing sleeve 42, and a right collar sealing ring 71-4 is provided between the right collar 71-3 and the dynamic sealing sleeve 42. A sliding opening is provided between the left collar 71-2 and the right collar 71-3, and the sealing part 72-1 of the T-shaped sealing ring 72 extends through the sliding opening to the centrifugal sleeve 71. The outer side of the sleeve 71; the T-shaped sealing ring 72 is composed of several sealing ring segments 72-3 connected end to end. Each sealing ring segment 72-3 has a locking part 72-4 at both ends, and the locking parts 72-4 at both ends of each sealing ring segment 72-3 are staggered. Specifically, in this embodiment, the locking parts 72-4 of two adjacent sealing ring segments 72-3 are slidably connected. When the end of the sealing part 72-1 abuts against the oil guide ring cover 43, there is a gap between the locking part 72-4 of any sealing ring segment 72-3 and its adjacent sealing ring segment 72-3. Through this gap, the centrifugal rotation mechanism 74 presses all the sealing ring segments 72-3 into the interior of the centrifugal sleeve 71. The gap position is as follows: Figure 10 As shown.

[0028] Specifically, such as Figure 7-9As shown, the centrifugal rotation mechanism 74 includes a left receiving ring 74-1 and a right receiving ring 74-2 symmetrically arranged on both sides of the T-shaped sealing ring 72. Each of the left receiving ring 74-1 and the right receiving ring 74-2 is provided with a number of mounting bases 74-3. Each mounting base 74-3 is rotatably connected to a centrifugal block 75 by a pin. The centrifugal block 75 is provided with a centrifugal part 75-1 and a contact part 75-2 at both ends. The weight of the centrifugal part 75-1 is greater than the weight of the contact part 75-2. The contact part 75-2 cooperates with the slot 72-5 on the abutment part 72-2.

[0029] Based on the above embodiments, after the wind turbine self-test system passes all tests, the wind turbine starts to run and generate electricity. The high-speed shaft 1 starts to rotate. Under the action of centrifugal force, the T-shaped sealing ring 72 on the centrifugal switch assembly 7 separates from the horizontal inner circle surface 43-2 of the oil guide ring cover 43 to form a passage gap 43-3. At this time, the lubricating oil in the oil drain groove 41-2 can flow into the gearbox through the oil guide gap 41-4 to provide auxiliary cooling and lubrication for the high-speed shaft generator side bearing 11. It can also flow through the passage gap 43-3 into the centrifugal gap 42-1 formed by the oil guide ring cover 43 and the dynamic sealing sleeve 42. When the wind turbine switches from the power generation state to the shutdown state, the high-speed shaft 1 stops rotating. The sealing ring 72 on the centrifugal switch assembly 7 on the right side of the oil drain groove 41-2 loses the centrifugal force support and is pressed back onto the horizontal inner circle surface 43-2 of the oil guide ring cover 43 to provide a static seal. It also provides a good seal for the oil mist inside the gearbox.

[0030] In this embodiment, as Figure 2 , Figure 4 and Figure 11 As shown, the magnetic fluid sealing assembly 5 is located on one side of the dynamic sealing sleeve 42. The magnetic fluid sealing assembly 5 includes an inner pole shoe 51 and an outer pole shoe 52 with the same structure. The inner walls of the inner pole shoe 51 and the outer pole shoe 52 are provided with pole teeth 53. Magnetic fluid is provided at the pole teeth 53 of the inner pole shoe 51 and the outer pole shoe 52. A permanent magnet ring 54 is connected between the inner pole shoe 51 and the outer pole shoe 52. The outer walls of the inner pole shoe 51, the permanent magnet ring 54, and the outer pole shoe 52 are all connected to the inner wall of the oil guide ring cover 43. One side of the outer pole shoe 52 is connected to the side wall of the outer end cover 3.

[0031] Based on the above embodiments, a magnetic fluid seal is formed at the connection between the high-speed shaft 1 and the outer end cover 3 by the inner pole shoe 51, the permanent magnet 54, the outer pole shoe 52, and the magnetic fluid, which plays a role in maintaining pressure in the pressure-holding ring cavity 61; when the high-speed shaft 1 is stopped for a long time, the magnetic fluid seal plays a role in sealing external dust, preventing external dust from entering the gearbox; in addition, the magnetic fluid in this embodiment is specifically an oleophobic magnetic fluid.

[0032] Specifically, an inner pole shoe sealing ring 51-1 and an outer pole shoe sealing ring 52-1 are respectively provided between the inner pole shoe 51 and the outer pole shoe 52 and the oil guide ring cover 43.

[0033] Based on the above embodiments, the gas inside the pressure-holding ring cavity 61 is prevented from leaking between the inner pole shoe 51 and the outer pole shoe 52 and the inner wall of the oil guide ring cover 43 by the inner pole shoe 51-1 and the outer pole shoe 52, thus ensuring that the pressure inside the pressure-holding ring cavity 61 is constant. It should be noted that the oil in this application is the lubricating oil used in the gearbox.

[0034] In this embodiment, as Figure 2 , Figure 4 and Figure 12 As shown, the air-guiding and pressure-maintaining assembly 6 includes a pressure-maintaining ring cavity 61 formed by the inner wall of the oil guide ring cover 43, the side wall of the dynamic sealing sleeve 42, the high-speed shaft 1, and the side wall of the inner pole shoe 51. The pressure-maintaining ring cavity 61 is connected to the pressure-stabilizing air-guiding channel 62 and the leakage collection cavity 63 opened on the oil guide ring cover 43. The pressure-stabilizing air-guiding channel 62 is connected to an external air source through the pressurization hole 62-1 opened on the outer end cover 3. One end of the leakage collection cavity 63 is connected to an overflow channel 63-2. The overflow channel 63-2 is located below the high-speed shaft 1. An overflow valve assembly 64 is provided inside the overflow channel 63-2. One end of the overflow channel 63-2 is connected to the inside of the gearbox through the pressure relief hole 63-1 opened on the oil guide ring 41 and the high-speed shaft generator side bearing.

[0035] Among them, the pressure stabilizing air channel 62 and the pressurizing hole 62-1 are provided with air guiding sealing rings 65, which are located on the side wall of the oil guide ring cover 43. The air guiding sealing rings 65 ensure that the gas will not escape between the outer end cover 3 and the oil guide ring cover 43, thus ensuring that the internal pressure of the pressure holding ring cavity 61 is constant.

[0036] Based on the above embodiments, the air source provides air pressure to the pressure-holding ring cavity 61 through the pressurization hole 62-1 and the pressure-stabilizing air guide channel 62. During this process, oil is injected into the oil discharge groove 41-2 through the oil injection hole 3-1, the oil injection channel 2-1 and the oil guide hole 41-1. After the oil is sealed through the centrifugal gap 42-1, it inevitably leaks towards the pressure-holding ring cavity 61. At this time, the inner side of the pressure-holding ring cavity 61 is sealed by the oil in the dynamic sealing gap 42-1. The gas pressure in the pressure-holding ring cavity 61 also plays a sealing role for the lubricating oil in the centrifugal gap 42-1. Therefore, the throttling effect of the tapered cross section, the pumping effect of the spiral groove, the centrifugal effect of the combination of the tapered cross section and the spiral groove, and the gas pressure effect of the pressure-holding ring cavity 61 all work together to seal the lubricating oil in the centrifugal gap 42-1. These four combined effects achieve pressure balance on the right side of the oil drain groove 41-2, so that the lubricating oil from the oil drain groove 41-2 can only enter the gearbox from its left side to provide auxiliary cooling and lubrication for the bearings and gears inside the gearbox.

[0037] In this embodiment, as Figure 12 As shown, the overflow valve assembly 64 includes a valve core 64-1. The valve core 64-1 abuts against one side of the inner wall of the overflow channel 63-2 to form a conical sealing surface. A valve core guide hole 64-2 is provided on the valve core 64-1. A pressure adjusting spring 64-3 is connected to one end of the valve core 64-1, and a pressure adjusting screw 64-4 is connected to one end of the pressure adjusting spring 64-3. The side wall of the pressure adjusting screw 64-4 abuts against the inner wall of the overflow channel 63-2. The overflow pressure at the conical sealing surface formed by the valve core 64-1 and the overflow channel 63-2 is adjusted by the compression of the pressure adjusting spring 64-3 by the pressure adjusting screw 64-4. An overflow pressure relief hole 64-5 is provided through the middle of the pressure adjusting screw 64-4. When the pressure in the pressure-holding ring cavity 61 is not higher than the overflow pressure of the overflow valve assembly 64, the overflow valve assembly 64 is in the closed state. Under the action of the pressure regulating spring 64-3, the valve core 64-1 is pressed against the inner wall of the overflow channel 63-2. The valve core 64-1 separates the leakage collection cavity 63 from the overflow channel 63-2 to maintain pressure. When the pressure in the pressure-holding ring cavity 61 reaches the overflow pressure of the overflow valve assembly, the pressure regulating spring 64-3 in the overflow channel 63-2 begins to compress, and the valve core 64-1 separates from the inner wall of the overflow channel 63-2, so that the leakage collection cavity 63 is connected to the pressure relief hole 63-1 through the overflow channel 63-2, the valve core oil guide hole 64-2, and the overflow pressure relief hole 64-5.

[0038] Based on the above embodiments, the combined effects of the tapered cross-section's throttling effect, the spiral groove's pumping effect, the centrifugal effect of the tapered cross-section and spiral groove, and the gas pressure effect of the pressure-holding ring cavity 61, all contribute to a synergistic sealing effect on the lubricating oil in the centrifugal gap 42-1. During this process, a small amount of lubricating oil inevitably leaks through the centrifugal gap 42-1 into the pressure-holding ring cavity 61. Under the influence of gravity and the pressure of the pressure-holding ring cavity 61, this leaked lubricating oil collects in the leakage collection cavity 63. The pressure-holding cavity 63, the pressure-holding ring cavity 61, and the pressure-stabilizing gas channel 62 form the pressure-holding cavity 6. With a constant volume, as the lubricating oil leaking into the leakage collection chamber 63 through the centrifugal gap 42-1 gradually increases, the gas inside the pressure holding chamber 61-1 is compressed, and the gas pressure inside the pressure holding chamber 61-1 gradually increases. When the gas pressure inside the pressure holding chamber 61-1 reaches the overflow pressure of the overflow valve assembly, the valve core 64-1 of the overflow valve assembly moves to the left and opens, allowing the lubricating oil in the leakage collection chamber 63 to enter the gearbox under the action of gas pressure. This ensures that the level of the lubricating oil leaking through the centrifugal gap 42-1 is always lower than the contact part between the pole teeth 53 of the magnetohydrodynamic seal and the high-speed shaft 1.

[0039] The working principle of this invention is as follows: the lubricating oil of the gearbox sealing oil circuit is introduced into the oil injection channel 2-1 through the oil injection hole 3-1 on the outer end cover 3, and then the lubricating oil enters the oil drain 41-2 through the oil storage tank 41-3 and the oil guide hole 41-1; when the wind turbine self-test system passes all the tests, the wind turbine starts to run the blades and start generating electricity, the high-speed shaft 1 starts to rotate, and the T-shaped sealing ring 72 on the centrifugal switch assembly 7 separates from the horizontal inner circular surface 43-2 of the oil guide ring cover 43 under the action of centrifugal force to form a passage gap 43-3. At this time, the lubricating oil in the oil drain 41-2 can flow into the gearbox through the oil guide gap 41-4 to provide auxiliary cooling and lubrication for the high-speed shaft generator side bearing 11, and can also flow through the passage gap 43-3 into the centrifugal gap 42-1 formed by the oil guide ring cover 43 and the dynamic sealing sleeve 42. At this time, since the dynamic sealing sleeve 42 has a conical shape with a cross-section that decreases from large to small from the inside out, the conical cross-section of the dynamic sealing sleeve 42 gradually decreases as the lubricating oil in the centrifugal gap 42-1 flows to the right, creating a throttling and pressure-reducing effect. This causes the lubricating oil pressure in the centrifugal gap 42-1 to gradually decrease in the leakage direction from left to right. Under pressure, the lubricating oil tends to gradually fill the entire centrifugal gap 42-1 from left to right. At the same time, the conical spiral groove 45 generates a pressure difference from right to left as the high-speed shaft 1 rotates at high speed, generating a pumping pressure from right to left on the lubricating oil in the centrifugal gap 42-1, further sealing the lubricating oil in the centrifugal gap 42-1. Furthermore, because the conical cross-section of the dynamic sealing sleeve 42 gradually increases from right to left, the conical spiral groove 45, during high-speed rotation with the high-speed shaft 1, causes the lubricating oil in the centrifugal gap 42-1 to experience significant centrifugal force. Due to the obstruction of the oil guide ring cap 43, the centrifugal effect of the lubricating oil manifests as a centrifugal force opposite to the leakage direction of the centrifugal gap 42-1, thus achieving a centrifugal sealing effect. In addition, the gas pressure in the pressure-holding ring cavity 61 also plays a sealing role for the lubricating oil in the centrifugal gap 42-1. Therefore, the throttling effect of the conical cross-section, the pumping effect of the spiral groove, the centrifugal effect of the combination of the conical cross-section and the spiral groove, and the gas pressure effect of the pressure-holding ring cavity 61 all contribute to a synergistic sealing effect on the lubricating oil in the centrifugal gap 42-1. These four combined effects achieve pressure balance on the right side of the oil drain groove 41-2, ensuring that the lubricating oil from the oil drain groove 41-2 can only enter the gearbox from its left side, providing auxiliary cooling and lubrication for the bearings and gears inside the gearbox.During this process, a small amount of lubricating oil will inevitably leak into the pressure-holding ring cavity 61 through the centrifugal gap 42-1. However, under the action of gravity and the pressure of the pressure-holding ring cavity, this leaked lubricating oil will collect in the leakage collection cavity 63. Since the volume of the pressure-holding cavity 61-1 formed by the leakage collection cavity 63, the pressure-holding ring cavity 61, and the pressure-stabilizing gas guide channel 62 is constant, as the amount of lubricating oil leaking into the pressure relief channel 63 through the centrifugal gap 42-1 gradually increases, the gas inside the pressure-holding cavity 61-1 is compressed, and the gas pressure inside the pressure-holding cavity 61-1 gradually increases. When the gas pressure inside the pressure-holding cavity 61-1 reaches the overflow pressure of the overflow valve assembly, the valve core 64-1 of the overflow valve assembly moves to the left and opens, allowing the lubricating oil leaking into the pressure relief channel 63 to enter the pressure relief channel 63 under the action of gas pressure. The lubricating oil leaking through the centrifugal gap 42-1 continues to accumulate in the pressure relief channel 63. When a certain amount is accumulated, it is discharged into the gearbox through the overflow valve assembly 64. This process is repeated, ensuring that the level of the lubricating oil leaking through the centrifugal gap 42-1 is always lower than the contact area between the pole teeth 53 of the magnetic fluid seal and the rotating shaft. During operation, the medium that the magnetic fluid seal needs to seal is always pressurized air, which plays a pressure-maintaining and sealing role in the pressure-maintaining cavity 61-1. This fully utilizes the advantage of magnetic fluid in reliably sealing gases. During the wind turbine's power generation process, the lubricating oil is sealed through gaps in the oil guide gap 41-4, the passage gap 43-3, and the centrifugal gap 42-1, with no mechanical or physical contact. This makes the entire sealing system a contactless, zero-leakage, ultra-long-life sealing solution.

[0040] When the wind turbine switches from generating to shut-down mode, the high-speed shaft 1 stops rotating. The sealing ring 72 on the centrifugal switch assembly 7 to the right of the oil drain trough 41-2, losing centrifugal support, re-tightens against the horizontal inner surface 43-2 of the oil guide ring cover 43, providing a static seal and effectively sealing the oil mist inside the gearbox. Subsequently, the wind turbine control system closes the gearbox sealing oil circuit. When the wind turbine switches from generating to shut-down mode, the pressure-holding cavity 61-1 remains a closed cavity due to the static sealing effect of the sealing ring 72.

[0041] It is worth noting that the rotational speed of the high-speed shaft 1 plays a crucial role in the formation of the passage gap 43-3 between the T-shaped seal ring 72 and the oil guide ring cover 43, the pumping effect of the spiral groove, and the centrifugal sealing effect of the sealing structure. Under different operating conditions of the wind turbine, the higher the rotational speed of the high-speed shaft, the larger the passage gap 43-3 formed by centrifugal action, and the more lubricating oil flowing from the oil drain groove 41-2 flows into the centrifugal gap 42-1 through the passage gap 43-3. However, the higher the rotational speed of the high-speed shaft, the greater the pumping pressure and centrifugal pressure in the centrifugal gap 42-1 that suppress leakage. Conversely, the lower the rotational speed of the high-speed shaft, the smaller the passage gap 43-3 formed by centrifugal action, and the less lubricating oil flowing from the oil drain groove 41-2 flows into the centrifugal gap 42-1 through the passage gap 43-3. Similarly, the lower the rotational speed of the high-speed shaft, the smaller the pumping pressure and centrifugal pressure in the centrifugal gap 42-1 that suppress leakage. This feature of adaptively adjusting leakage flow and sealing effect with rotational speed enables the sealing device to always meet the zero leakage requirement under complex operating conditions such as frequent start-stop and speed change of wind turbine units.

[0042] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A contactless, zero-leakage combined sealing device for the high-speed shaft of a wind turbine gearbox, disposed at the high-speed shaft of the wind turbine gearbox, the high-speed shaft being mounted inside the high-speed shaft end cover of the gearbox via a generator-side bearing, an outer end cover being disposed on one side of the high-speed shaft end cover, the end of the high-speed shaft penetrating the outer end cover and extending to the outside of the outer end cover, the sealing device being used to seal the gap between the high-speed shaft inside the wind turbine gearbox and the high-speed shaft end cover of the gearbox, characterized in that... The sealing device includes a sealing sleeve assembly, a centrifugal switch assembly, a magnetic fluid sealing assembly, and a gas guiding and pressure maintaining assembly. The sealing sleeve assembly and the centrifugal switch assembly form a gap seal, and the sealing sleeve assembly, the gas guiding and pressure maintaining assembly, and the magnetic fluid sealing assembly together form a pneumatic seal. The magnetic fluid sealing assembly forms a magnetic fluid seal. Through the synergistic effect of the gap seal, the pneumatic seal, and the magnetic fluid seal, the high-speed shaft of the wind turbine gearbox and the outer end cover are sealed together. The sealing sleeve assembly is located on the outside of the high-speed shaft generator-side bearing. The sealing sleeve assembly includes an oil guide ring and a conical dynamic sealing sleeve. The oil guide ring is located on the outside of the high-speed shaft generator-side bearing and is mounted on the inner wall of the gearbox high-speed shaft end cover. An oil guide gap is provided between the oil guide ring and the high-speed shaft. Several oil guide holes are provided through the oil guide ring. Each oil guide hole communicates with the outside through an oil injection channel on the gearbox high-speed shaft end cover and an oil injection hole on the outer end cover. An oil drain groove is provided on the inner wall of the oil guide ring. The oil drain groove is connected to several oil guide holes; the dynamic sealing sleeve is sleeved on the first shoulder of the high-speed shaft, and the large-diameter end of the dynamic sealing sleeve is located on one side of the oil guide ring; an oil guide ring cover is sleeved on the outside of the dynamic sealing sleeve, the oil guide ring cover is connected to the inner wall of the gearbox high-speed shaft end cover, one side of the oil guide ring cover abuts against the side wall of the oil guide ring, one side of the inner wall of the oil guide ring cover is provided with a conical structure that matches the dynamic sealing sleeve, the other side of the oil guide ring cover is connected to the side wall of the outer end cover, and a centrifugal gap is provided between the inner wall of the oil guide ring cover and the dynamic sealing sleeve; The centrifugal switch assembly is sleeved on the second shoulder of the high-speed shaft and is located between the generator-side bearing of the high-speed shaft and the dynamic sealing sleeve. The centrifugal switch assembly includes a hollow centrifugal sleeve with a T-shaped sealing ring inside. The T-shaped sealing ring includes a sealing part and an abutting part. The sealing part is slidably connected to the side wall of the centrifugal sleeve through a sliding port. One end of the sealing part abuts against the inner wall of the oil guide ring cover. A pre-tightening spring connected to the inner wall of the centrifugal sleeve is provided on the inner diameter side of the abutting part. A centrifugal rotation mechanism is provided on the abutting part. Under the action of centrifugal force, the sealing part of the T-shaped sealing ring is pressed into the interior of the centrifugal sleeve by the centrifugal rotation mechanism. The magnetic fluid sealing assembly is located on one side of the dynamic sealing sleeve. The magnetic fluid sealing assembly includes an inner pole shoe and an outer pole shoe with the same structure. The inner walls of the inner pole shoe and the outer pole shoe are provided with pole teeth. Magnetic fluid is provided at the pole teeth of the inner pole shoe and the outer pole shoe. A permanent magnet ring is connected between the inner pole shoe and the outer pole shoe. The outer walls of the inner pole shoe, the permanent magnet ring, and the outer pole shoe are all connected to the inner wall of the oil guide ring gland. One side of the outer pole shoe is connected to the side wall of the outer end cap. The pressure-maintaining and air-guiding assembly includes a pressure-maintaining ring cavity formed by the inner wall of the oil guide ring cover, the side wall of the dynamic sealing sleeve, the high-speed shaft, and the side wall of the inner pole shoe. The pressure-maintaining ring cavity is connected to a pressure-stabilizing air-guiding channel and a leakage collection cavity opened on the oil guide ring cover. The pressure-stabilizing air-guiding channel is connected to an external air source through a pressurization hole opened on the outer end cover. One end of the leakage collection cavity is connected to an overflow channel located below the high-speed shaft. An overflow valve assembly is installed inside the overflow channel. One end of the overflow channel is connected to the inside of the gearbox through a pressure relief hole opened on the oil guide ring and the generator side bearing of the high-speed shaft. The overflow valve assembly maintains pressure in the pressure-maintaining ring cavity and discharges the lubricating oil leaking into the pressure-maintaining ring cavity into the gearbox through the overflow valve assembly.

2. The contactless zero-leakage combined sealing device for a high-speed shaft of a wind turbine gearbox according to claim 1, characterized in that, A sleeve sealing ring is provided between the dynamic sealing sleeve and the high-speed shaft. The large-diameter end of the dynamic sealing sleeve is connected to the first shoulder of the high-speed shaft, and a sleeve retaining ring is provided at the small-diameter end of the dynamic sealing sleeve. Several spiral grooves are evenly opened on the side wall of the dynamic sealing sleeve.

3. The contactless zero-leakage combined sealing device for a high-speed shaft of a wind turbine gearbox according to claim 2, characterized in that, A bearing retainer ring is provided on one side of the high-speed shaft generator side bearing, and the bearing retainer ring is located between the high-speed shaft generator side bearing and the oil guide ring. An oil storage groove is provided on the outer wall of the oil guide ring, and the oil storage groove is connected to several oil guide holes.

4. The contactless zero-leakage combined sealing device for a high-speed shaft of a wind turbine gearbox according to claim 3, characterized in that, Oil guide ring sealing rings are provided between the oil guide ring cover and the oil guide ring, as well as between the oil guide ring cover and the high-speed shaft end cover of the gearbox.

5. The contactless zero-leakage combined sealing device for a high-speed shaft of a wind turbine gearbox according to claim 4, characterized in that, The centrifugal sleeve includes a mounting ring with a left collar and a right collar symmetrically arranged on both sides. The T-shaped sealing ring is fastened to the inside of the centrifugal sleeve by the left collar and the right collar. The left collar abuts against the second shoulder of the high-speed shaft, and a left collar sealing ring is provided between the left collar and the second shoulder. The right collar abuts against the side wall of the dynamic sealing sleeve, and a right collar sealing ring is provided between the right collar and the dynamic sealing sleeve. A sliding port is provided between the left collar and the right collar, and the sealing part of the T-shaped sealing ring extends to the outside of the centrifugal sleeve through the sliding port. The T-shaped sealing ring is composed of several sealing ring segments connected end to end. Each sealing ring segment has a locking part at both ends, and the locking parts at the beginning and end of each sealing ring segment are staggered.

6. The contactless, zero-leakage combined sealing device for a high-speed shaft of a wind turbine gearbox according to claim 5, characterized in that, The centrifugal rotation mechanism includes a left receiving ring and a right receiving ring symmetrically arranged on both sides of the T-shaped sealing ring. Each left receiving ring and the right receiving ring are provided with several mounting bases. Each mounting base is rotatably connected to a centrifugal block by a pin. The centrifugal block has a centrifugal part and a contact part at both ends. The weight of the centrifugal part is greater than the weight of the contact part. The contact part and the groove on the abutment part cooperate with each other.

7. The contactless zero-leakage combined sealing device for a high-speed shaft of a wind turbine gearbox according to claim 1, characterized in that, The inner pole shoe and the outer pole shoe are respectively provided with an inner pole shoe sealing ring and an outer pole shoe sealing ring between them and the oil guide ring cover.

8. The contactless zero-leakage combined sealing device for a high-speed shaft of a wind turbine gearbox according to claim 1, characterized in that, The pressure-stabilizing air guide channel and the pressurization hole are provided with an air guide sealing ring, which is located on the side wall of the oil guide ring cover.

9. A contactless, zero-leakage combined sealing device for a high-speed shaft of a wind turbine gearbox according to claim 6, characterized in that, The overflow valve assembly includes a valve core, which abuts against one side of the inner wall of the overflow channel to form a conical sealing surface. The valve core has an oil guide hole. One end of the valve core is connected to a pressure adjusting spring, and the other end of the spring is connected to a pressure adjusting screw. The side wall of the pressure adjusting screw abuts against the inner wall of the overflow channel. The pressure adjusting screw adjusts the compression of the pressure adjusting spring to create overflow pressure at the conical sealing surface formed by the valve core and the overflow channel. An overflow pressure relief hole is provided through the middle of the pressure adjusting screw. When the pressure is maintained... When the pressure in the ring cavity is not higher than the overflow pressure of the overflow valve assembly, the overflow valve assembly is in the closed state. Under the action of the pressure regulating spring, the valve core is pressed against the inner wall of the overflow channel, and the valve core separates the leakage collection chamber from the overflow channel to maintain pressure. When the pressure in the pressure-maintaining ring cavity reaches the overflow pressure of the overflow valve assembly, the pressure regulating spring in the overflow channel begins to compress, the valve core separates from the inner wall of the overflow channel, and the leakage collection chamber is connected through the overflow channel, the valve core guide hole, and the overflow pressure relief hole and pressure relief hole.

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