Air-assisted sealed high-speed shaft system without external air source

Abstract

The invention belongs to the field of mechanical transmission and sealing, particularly relates to an air-assisted sealing high-speed shaft system without an external air source, and aims to solve the problems that the machining difficulty of a rotor is increased, the torsion transmission strength of the shaft is influenced and unbalance of the rotor is easily caused due to the fact that a complex air channel is machined on a high-speed rotor shaft in the existing scheme. According to the scheme, a cavity is formed in the middle of a static structure assembly, two air inducing pipes are symmetrically fixed in the cavity front and back, a first air channel of each air inducing pipe is further communicated with the outside of the static structure assembly, the front end and the rear end of a high-speed rotor assembly are connected with the static structure assembly, and the air stirring end of the high-speed rotor assembly is located between the two air inducing pipes; according to the invention, a mature sealing structure does not need to be modified, and the rotor does not need to be specially designed and processed; an external air source does not need to be introduced to assist sealing, the sealing device can adapt to positive and negative rotation operation conditions, and compared with conventional air-entraining non-contact sealing, the use cost of equipment is reduced, and the sealing effect is improved.

Description

Technical Field

[0001] The present invention belongs to the field of mechanical transmission and sealing, and specifically relates to a high-speed shaft system with air-assisted sealing that does not require an external air source. The principle of the air-assisted sealing can be applied to the sealing design of high-speed shaft systems such as gear shafts and rotating main shafts. Background Art

[0002] In order to achieve excellent rotor dynamics characteristics when designing a high-speed shaft system, it is often necessary to place the center of gravity of the shaft head external mount as close to the support bearing as possible, so that the support bearing and rotor shaft combination can have higher stiffness characteristics, thereby obtaining a higher critical speed and operating stability. However, placing the bearing as close to the center of gravity of the shaft head external mount as possible means that the bearing seal is closer to structures such as the rotor shaft head flange, compressing the seal design space, and structures such as the connecting bolts at the shaft head flange will cause a wind stirring effect, further causing a pressure difference on both sides of the high-speed seal, increasing the design difficulty of the high-speed seal.

[0003] At present, common high-speed seals include contact seals and non-contact seals. Contact seals can achieve better sealing effects and have advantages such as small leakage, but due to the contact sealing form, there will be friction and heat, which will affect the reliability of the rotor shaft operation. In addition, contact seals are life parts, and their sealing limit linear speed is limited by the sealing material. The current maximum application limit speed is about 50m / s. At the same time, the operating temperature is also limited by the sealing material, and its application in low and high temperature environments is limited; non-contact seals have almost no restrictions on their operating temperature and sealing life due to their non-contact sealing principle. Generally, non-contact seals with strict leakage requirements often need to introduce air film or liquid film to achieve better sealing effects, and need to add auxiliary air supply equipment, which increases the cost of use and reduces equipment maintainability.

[0004] High-speed shafting with conventional non-contact sealing design can meet the sealing requirements when the speed is relatively low, but with the increase of the linear speed at the rotor seal, the connecting bolts at the shaft head flange and other structures will cause the wind stirring effect to increase, and the pressure difference on both sides of the high-speed seal will increase the sealing difficulty. For example, in aircraft engines, in order to improve the sealing of each bearing cavity, it is often necessary to equip an air system to bleed air to the bearing cavity seal; in addition, there are non-contact sealing structures such as spiral seals, which generate airflow through the sealing structure itself to improve the sealing effect, but the spiral seal cannot adapt to bidirectional rotation; Chinese patent No. CN114198485B, published on July 9, 2024, "A high-speed shafting with centrifugal auxiliary seal", sets an air channel on the shaft, and assists the oil return at the seal through the pressure difference caused by the operation of the rotor itself. Compared with conventional air-bleeding non-contact seals, it reduces the use cost of the equipment and improves the sealing effect, but processing complex channels on the high-speed rotor shaft increases the difficulty of rotor processing on the one hand, and affects the torsional strength of the shaft on the other hand, and easily causes rotor imbalance. Therefore, it is necessary to optimize the design on this basis and develop a high-speed shaft system with simple processing and design processability and air-assisted sealing that does not require an external air source. Summary of the invention

[0005] The purpose of the patent of this invention: The invention is to solve the problem that the existing solution processes complex channels on the high-speed rotor shaft, which on the one hand increases the difficulty of rotor processing, and on the other hand affects the torsional strength of the shaft and easily causes rotor imbalance. The present invention provides a high-speed shaft system with air-assisted sealing that does not require an external air source.

[0006] The object of the present invention is achieved as follows: a high-speed shaft system with air-assisted sealing that does not require an external air source, comprising a stationary structural assembly, a high-speed rotor assembly and two induced draft ducts;

[0007] A cavity is provided in the middle of the stationary structure component, and two air ducts are symmetrically fixed in the cavity front and back. A channel of each air duct is also connected to the outside of the stationary structure component. The front and rear ends of the high-speed rotor component are connected to the stationary structure component, and the stirring end of the high-speed rotor assembly is located between the two air ducts.

[0008] Further, the high-speed rotor assembly includes a gear shaft, a rear fulcrum bearing locking nut assembly, a shaft head flange, a shaft head flange locking nut and two sets of bearing structures;

[0009] A gear is installed in the middle of the gear shaft, and a plurality of wind stirring ends are arranged on the gear spokes. The wind stirring ends are convex structures or concave structures arranged on the gear spokes, and the wind stirring ends face the outlet of the induced air duct;

[0010] The front end of the gear shaft passes through a set of bearing assemblies and the shaft head flange in sequence and is fixed with the shaft head flange locking nut, and the rear end of the gear shaft passes through another set of bearing assemblies and is fixed with the rear fulcrum bearing locking nut. The two sets of bearing assemblies are used to support the gear shaft to rotate along the two sets of bearing assemblies.

[0011] Further, the bearing structure includes a bearing inner ring spacer and two spindle bearings;

[0012] The bearing inner ring spacer and the two main shaft bearings are all sleeved on the gear shaft, and the bearing inner ring spacer is located between the two main shaft bearings.

[0013] Further, the stationary structural assembly includes a gearbox, a rear pivot bearing bushing, a rear pivot bearing outer ring pressure ring, a blind cover, a front pivot bearing bushing, a front pivot bearing outer ring pressure ring and a non-contact sealing ring;

[0014] The front pivot bearing bushing is fixed at the front end of the gearbox, the front pivot bearing bushing is sleeved on the outside of the front bearing structure, the front pivot bearing outer ring pressure ring is arranged in the front pivot bearing bushing and is located in front of the bearing structure, the non-contact sealing ring is located in front of the front pivot bearing bushing and is close to the front pivot bearing bushing, the rear end convex ring of the non-contact sealing ring presses against the front pivot bearing outer ring pressure ring and is inserted into the front pivot bearing bushing; an axial gap and a radial gap are left between the non-contact sealing ring and the shaft head flange;

[0015] A channel 2 is provided on the upper part of the front pivot bearing bushing and is connected to the adjacent channel 1. A channel 3 is provided on the non-contact sealing ring and is connected to the channel 2. The outlet end of the channel 3 faces the radial gap between the non-contact sealing ring and the shaft head flange.

[0016] The rear pivot bearing bushing and the blind cover are fixed to the rear end of the gearbox in sequence from front to back, the rear pivot bearing bushing is sleeved on the outside of the bearing structure at the rear end, the rear pivot bearing outer ring pressure ring is arranged in the rear pivot bearing bushing and is located behind the bearing structure, and the front end convex ring of the blind cover presses against the rear pivot bearing outer ring pressure ring and is inserted into the rear pivot bearing bushing;

[0017] A channel six communicating with an adjacent channel one is arranged on the upper part of the rear pivot bearing bushing, and a channel seven communicating with the channel six and the outside is arranged on the cover.

[0018] Furthermore, the non-contact sealing ring is provided with a channel four connecting the channel three with the outside;

[0019] The non-contact sealing ring is provided with a channel five connecting the channel three with the outside, and a plug is connected to the channel five.

[0020] Furthermore, a bearing outer ring oil spray spacer is provided between the two main shaft bearings of each group of bearing structures, an oil groove is left on the outer ring of the bearing outer ring oil spray spacer, an oil port 1 arranged on the front pivot bearing bushing is provided at the bottom of the second channel, the second channel is connected with the oil port 1, and the oil port 1 is located above the oil groove of the adjacent bearing outer ring oil spray spacer;

[0021] The bottom of channel six is ​​provided with oil port two which is arranged on the rear pivot bearing bushing, channel six is ​​communicated with oil port two, and oil port two is located above the oil groove of the oil spray spacer ring of the adjacent bearing outer ring.

[0022] Furthermore, a notch 1 is provided at the front lower part of the front pivot bearing outer ring pressure ring, and a channel 8 is provided at the lower part of the front pivot bearing bushing to connect the notch 1 with the internal space of the gear box;

[0023] A notch 2 is arranged at the rear lower part of the rear pivot bearing outer ring pressure ring, and a channel 9 is arranged at the lower part of the rear pivot bearing bushing for connecting the notch 2 with the inner space of the gear box.

[0024] Furthermore, a channel ten connected to the channel nine is provided on the non-contact sealing ring, and an outlet end of the channel ten faces the radial gap between the non-contact sealing ring and the shaft head flange.

[0025] Furthermore, an oil flinger is provided between the shaft head flange and the adjacent bearing assembly and rotates synchronously with the gear shaft. The oil flinger is located inside the outer ring pressure ring of the front fulcrum bearing. An oil port three is provided on the upper part of the outer ring pressure ring of the front fulcrum bearing, and an oil port four corresponding to the oil port three and connected to the channel two is provided on the front fulcrum bearing bushing.

[0026] Furthermore, n oil return sieve holes with a diameter of D are arranged at the lower part of the induced draft pipe, and the oil return sieve holes allow the droplets generated by the oil-gas mixture to flow back into the gear box.

[0027] Beneficial effects:

[0028] No air from an independent power source is introduced to assist the non-contact seal, and no additional non-contact seal parts are designed. There is no need for special design and processing of the shaft system rotor. The centrifugal stirring effect of the raised or recessed structure on the gear spokes on the rotor shaft is used to design the vents in combination with the Bernoulli principle. Through a simple and reliable auxiliary sealing structure, the oil return smoothness of the oil slinger ring, oil injection ring cavity, etc. of the high-speed shaft system is improved. The present invention does not require modification of the mature sealing structure, nor does it require special design and processing of the rotor; it uses its own rotating parts to generate negative pressure, does not require the introduction of an external air source to assist the seal, and can adapt to forward and reverse operating conditions. Compared with conventional air-inducing non-contact seals, it reduces the use cost of the equipment and improves the sealing effect. It is a high-speed shaft system with simple processing and design processability and air-assisted sealing that does not require an external air source. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 The schematic diagram of a high-speed shaft system of the present invention that does not require an external air source for air auxiliary sealing Figure 1 ;

[0030] Figure 2 The schematic diagram of a high-speed shaft system of the present invention with air auxiliary seal that does not require an external air source Figure 2 ;

[0031] Figure 3 The schematic diagram of a high-speed shaft system of the present invention that does not require an external air source for air auxiliary sealing Figure 3 ;

[0032] Figure 4 is a schematic diagram of an air duct of the present invention;

[0033] Figure 5 yes Figure 4 A partial enlarged schematic diagram of . DETAILED DESCRIPTION

[0034] Specific implementation method 1: A high-speed shaft system with air-assisted sealing that does not require an external air source, comprising a stationary structure assembly 10, a high-speed rotor assembly 20 and two air ducts 30;

[0035] A cavity is provided in the middle of the stationary structure component 10, and two air ducts 30 are symmetrically fixed in the cavity front and back. A channel 30-1 of each air duct 30 is also connected to the outside of the stationary structure component 10. Both the front and rear ends of the high-speed rotor component 20 are connected to the stationary structure component 10, and the wind stirring end of the high-speed rotor component 20 is located between the two air ducts 30.

[0036] In this embodiment: the end of channel one is close to the stirring end of the high-speed rotor assembly, the stirring end has a high linear velocity, and has a strong stirring centrifugal effect on the nearby air, thereby forming a negative pressure zone in zone IV, and the oil-gas mixture is thrown back into the stationary structure assembly.

[0037] Specific embodiment 2: A high-speed shaft system with air-assisted sealing that does not require an external air source, the high-speed rotor assembly 20 includes a gear shaft 21, a rear fulcrum bearing locking nut assembly 25, a shaft head flange 26, a shaft head flange locking nut 27 and two sets of bearing structures;

[0038] A gear is installed in the middle of the gear shaft 21, and a plurality of wind stirring ends 22 are provided on the gear spokes. The wind stirring ends 22 are convex structures or concave structures provided on the gear spokes, and the wind stirring ends 22 face the outlet of the air duct 30;

[0039] The front end of the gear shaft 21 passes through a set of bearing assemblies and the shaft head flange 26 in sequence and is fixed to the shaft head flange locking nut 27. The rear end of the gear shaft 21 passes through another set of bearing assemblies and is fixed to the rear fulcrum bearing locking nut 25. The two sets of bearing assemblies are used to support the gear shaft 21 to rotate along the two sets of bearing assemblies.

[0040] In this embodiment: the end of channel one is close to the wind-stirring structure of the high-speed rotor assembly. Since the linear velocity of the wind-stirring structure is relatively high and the raised and recessed structures have a strong stirring and centrifugal effect on the nearby air, a negative pressure zone is formed in zone IV, and the oil-gas mixture is thrown back into the stationary structure assembly.

[0041] Other implementations are the same as the first specific implementation.

[0042] Specific embodiment 3: A high-speed shaft system with air-assisted sealing that does not require an external air source, the bearing structure includes a bearing inner ring spacer 23 and two main shaft bearings 24;

[0043] The bearing inner ring spacer 23 and the two main shaft bearings 24 are both mounted on the gear shaft 21 , and the bearing inner ring spacer 23 is located between the two main shaft bearings 24 .

[0044] Other implementations are the same as the second specific implementation.

[0045] Specific embodiment 4: A high-speed shaft system with air-assisted sealing that does not require an external air source, the stationary structure assembly 10 includes a gear box 18, a rear pivot bearing bushing 11, a rear pivot bearing outer ring pressure ring 12, a cover 13, a front pivot bearing bushing 15, a front pivot bearing outer ring pressure ring 16 and a non-contact sealing ring 17;

[0046] The front pivot bearing bushing 15 is fixed at the front end of the gear box 18, and the front pivot bearing bushing 15 is sleeved on the outside of the front bearing structure, and the front pivot bearing outer ring pressure ring 16 is arranged in the front pivot bearing bushing 15 and is located in front of the bearing structure, and the non-contact sealing ring 17 is located in front of the front pivot bearing bushing 15 and is close to the front pivot bearing bushing 15, and the rear end convex ring of the non-contact sealing ring 17 presses against the front pivot bearing outer ring pressure ring 16 and is inserted into the front pivot bearing bushing 15; an axial gap and a radial gap are left between the non-contact sealing ring 17 and the shaft head flange 26;

[0047] A second channel 15-1 communicating with the adjacent first channel 30-1 is provided on the upper portion of the front pivot bearing bushing 15, and a third channel 17-1 communicating with the second channel 15-1 is provided on the non-contact sealing ring 17, wherein the outlet end of the third channel 17-1 faces the radial gap between the non-contact sealing ring 17 and the shaft head flange 26;

[0048] The rear pivot bearing bushing 11 and the cover 13 are fixed to the rear end of the gear box 18 in sequence from front to back. The rear pivot bearing bushing 11 is sleeved on the outside of the bearing structure at the rear end. The rear pivot bearing outer ring pressure ring 12 is arranged in the rear pivot bearing bushing 11 and is located behind the bearing structure. The front end convex ring of the cover 13 presses against the rear pivot bearing outer ring pressure ring 12 and is inserted into the rear pivot bearing bushing 11.

[0049] A channel six 11-1 communicating with the adjacent channel one 30-1 is provided on the upper portion of the rear pivot bearing bushing 11, and a channel seven 13-1 communicating with the channel six 11-1 and the outside is provided on the cover 13.

[0050] In this embodiment: the front pivot bearing group near the shaft head flange is restricted in axial movement under the clamping action of the shaft head flange locking nut, the oil throwing ring, and the front pivot bearing outer ring pressure ring, while the rear pivot bearing group as a whole is not axially limited and is in an axially movable state as a whole, thereby adapting to the axial thermal expansion of the high-speed rotor caused by high temperature. The shaft head flange is axially advanced under the clamping force of the shaft head flange locking nut, and a high-precision connection with the gear shaft is achieved through a cone fit. The outer diameter of the shaft head flange is set as a sealing surface, and the non-contact sealing ring forms a reliable non-contact seal with it, and the entire shaft system structure is compact.

[0051] Among them, the distance L2 between the shaft head flange and the nearby bearing group fulcrum and L1 between the shaft head flange and the non-contact sealing ring are important design parameters: the V area between the shaft head flange and the non-contact seal forms a negative pressure area due to centrifugal action. The smaller L1 is, the more severe the centrifugal action is. Excessive L1 will compress the design space of the seal and oil return. In order to increase the critical speed of the high-speed rotor assembly, a reasonable L2 should be controlled. If L2 is too small, the design space of the seal and oil return will be further compressed.

[0052] Other implementations are the same as the third specific implementation.

[0053] Specific implementation method 5: A high-speed shaft system with air-assisted sealing that does not require an external air source, wherein a non-contact sealing ring 17 is provided with a channel 4 17-2 connecting the channel 3 17-1 with the outside world;

[0054] The non-contact sealing ring 17 is provided with a channel 5 17 - 3 connecting the channel 3 17 - 1 with the outside, and a plug is connected to the channel 5 17 - 3 .

[0055] In this embodiment: a channel four connecting channel three with the outside world is provided on the non-contact sealing ring for air intake. In order to avoid the negative pressure of zone V offsetting the air intake effect of the air duct, the ventilation air intake hole of the non-contact seal is avoided facing zone V at the non-contact sealing ring.

[0056] The non-contact sealing ring is provided with a channel five connecting the channel three with the outside for air intake.

[0057] Other implementations are the same as the fourth specific implementation.

[0058] Specific implementation method six: A high-speed shaft system with air-assisted sealing that does not require an external air source, a bearing outer ring oil spray spacer 14 is provided between the two main shaft bearings 24 of each bearing structure, an oil groove is left on the outer ring of the bearing outer ring oil spray spacer 14, an oil port 15-3 arranged on the front fulcrum bearing bushing 15 is provided at the bottom of the second channel 15-1, the second channel 15-1 is connected with the oil port 15-3, and the oil port 15-3 is located above the oil groove of the adjacent bearing outer ring oil spray spacer 14;

[0059] The bottom of channel six 11-1 is provided with an oil port two 11-3 arranged on the rear fulcrum bearing bushing 11, and channel six 11-1 is connected with oil port two 11-3, and oil port two 11-3 is located above the oil groove of the adjacent bearing outer ring oil injection spacer ring 14.

[0060] In this embodiment: by matching and grinding the inner ring spacer ring of the bearing and the oil spray spacer ring of the outer ring of the bearing, the four supporting main shaft bearings are paired in O-shape, and the grease enters the oil groove of the oil spray spacer ring of the outer ring of the bearing, and the grease enters channel six from channel one, and finally falls into the oil groove of the oil spray spacer ring of the outer ring of the bearing through oil port two.

[0061] The oil droplets generated in channel 2 drip along the oil port 1 to the space between the two bearings for lubrication. The oil droplets generated in channel 6 drip along the oil port 2 to the space between the two bearings for lubrication.

[0062] Other implementations are the same as the fifth specific implementation.

[0063] Specific embodiment 7: A high-speed shaft system with air-assisted sealing that does not require an external air source, a notch 16-2 is provided at the front lower part of the front pivot bearing outer ring pressure ring 16, and a channel 8 15-2 is provided at the lower part of the front pivot bearing bushing 15 to connect the notch 16-2 with the internal space of the gear box 18;

[0064] A notch 12 - 1 is provided at the rear lower portion of the rear fulcrum bearing outer ring pressure ring 12 , and a channel 11 - 2 is provided at the lower portion of the rear fulcrum bearing bushing 11 to connect the notch 12 - 1 with the internal space of the gear box 18 .

[0065] In this embodiment, the grease overflowing from the front bearing assembly after lubrication flows along the notch 1 to the channel 8 and returns to the bearing box, and the grease overflowing from the rear bearing assembly after lubrication flows along the notch 2 to the channel 9 and returns to the bearing box.

[0066] Other implementations are the same as the sixth implementation.

[0067] Specific embodiment eight: A high-speed shaft system with air-assisted sealing that does not require an external air source, wherein a channel ten 17-4 connected to the channel nine 11-2 is provided on the non-contact sealing ring 17, and the outlet end of the channel ten 17-4 faces the radial gap between the non-contact sealing ring 17 and the shaft head flange 26.

[0068] In this embodiment: channel ten is used to connect the radial gap between the non-contact sealing ring and the shaft head flange, so that the internal space of the bearing box is connected to the external environment, balancing the internal and external air pressures, and ensuring that the condensed oil droplets can flow from top to bottom.

[0069] Other implementations are the same as the specific implementation method seven.

[0070] Specific embodiment nine: A high-speed shaft system with air-assisted sealing that does not require an external air source, an oil flinger 28 that rotates synchronously with the gear shaft 21 is provided between the shaft head flange 26 and the adjacent bearing assembly, the oil flinger 28 is located in the front fulcrum bearing outer ring pressure ring 16, the front fulcrum bearing outer ring pressure ring 16 has an oil port three 16-1 on the upper part, and the front fulcrum bearing bushing 15 has an oil port four 15-4 that corresponds to the oil port three 28-1 and is connected to the channel two 15-1.

[0071] In this embodiment, the oil and gas droplets entering the oil port three fall on the oil slinger ring and are slinger back into the bearing box through the oil port four and the channel eight.

[0072] Other implementations are the same as the eighth specific implementation.

[0073] Specific embodiment 9: A high-speed shaft system with air-assisted sealing that does not require an external air source. n oil return sieve holes 30 - 2 with a diameter of D are set at the lower part of the air duct 30. The oil return sieve holes 30 - 2 allow the droplets generated by the collected oil-gas mixture to flow back into the gear box 18.

[0074] In this embodiment, the number of holes n and the diameter D are important design parameters. The ventilation cross-section of the induced air duct here cannot be larger than the ventilation cross-section of zones II and III, otherwise the oil and gas extraction effect on the oil return zone will be weakened. In addition, in order to avoid the negative pressure of zone V offsetting the air ducting effect of the induced air duct at the non-contact seal, the ventilation inlet holes of the non-contact seal should avoid facing zone V.

[0075] Working principle: Design ventilation air path on the bearing bushing, and connect the induced draft pipe to the gear spoke with high linear speed of high-speed gear. The gear spoke is provided with raised or recessed features to enhance its centrifugal stirring effect. Therefore, due to the Bernoulli principle, negative pressure is generated at the induced draft pipe, so that the oil-gas mixture in the sealing chamber, oil return chamber, etc. is sucked into the bearing bushing, and led to the gear spoke with high linear speed of high-speed gear, and thrown into the gear box. In order to avoid the reflux of oil and gas after condensation at the induced draft pipe, a small oil return hole is set at the lower part of the induced draft pipe to prevent the reflux of condensed oil and gas. This scheme does not require modification of the mature sealing structure, nor does it require special design of the rotor. The processing and design process are simple, and air-assisted sealing without the introduction of external air source is required, and it can adapt to forward and reverse operation conditions. Compared with conventional induced draft non-contact seals, it reduces the use cost of the equipment and improves the sealing effect. It is a high-speed shaft system with simple processing and design process and air-assisted sealing without external air source.

Claims

1. A high-speed shaft system with air-assisted sealing that does not require an external air source, characterized in that: It comprises a stationary structure assembly (10), a high-speed rotor assembly (20) and two air ducts (30); A cavity is provided in the middle of the stationary structure component (10), and two air ducts (30) are symmetrically fixed in the cavity in the front and rear directions. A channel 1 (30-1) of each air duct (30) is also connected to the outside of the stationary structure component (10). Both the front and rear ends of the high-speed rotor component (20) are connected to the stationary structure component (10), and the wind stirring end of the high-speed rotor component (20) is located between the two air ducts (30).

2. A high-speed shaft system with air-assisted sealing that does not require an external air source according to claim 1, characterized in that: The high-speed rotor assembly (20) comprises a gear shaft (21), a rear fulcrum bearing locking nut assembly (25), a shaft head flange (26), a shaft head flange locking nut (27) and two sets of bearing structures; A gear is installed in the middle of the gear shaft (21), and a plurality of wind stirring ends (22) are provided on the gear spokes. The wind stirring ends (22) are convex structures or concave structures arranged on the gear spokes, and the wind stirring ends (22) face the outlet of the air duct (30); The front end of the gear shaft (21) passes through a set of bearing assemblies and a shaft head flange (26) in sequence and is fixed to the shaft head flange locking nut (27). The rear end of the gear shaft (21) passes through another set of bearing assemblies and is fixed to the rear fulcrum bearing locking nut (25). The two sets of bearing assemblies are used to support the gear shaft (21) to rotate along the two sets of bearing assemblies.

3. A high-speed shaft system with air-assisted sealing that does not require an external air source according to claim 2, characterized in that: The bearing structure comprises a bearing inner ring spacer (23) and two main shaft bearings (24); The bearing inner ring spacer (23) and two main shaft bearings (24) are both sleeved on the gear shaft (21), and the bearing inner ring spacer (23) is located between the two main shaft bearings (24).

4. A high-speed shaft system with air-assisted sealing that does not require an external air source according to claim 3, characterized in that: The stationary structure assembly (10) comprises a gear box (18), a rear pivot bearing bushing (11), a rear pivot bearing outer ring pressure ring (12), a cover (13), a front pivot bearing bushing (15), a front pivot bearing outer ring pressure ring (16) and a non-contact sealing ring (17); The front pivot bearing bushing (15) is fixed at the front end of the gear box (18), the front pivot bearing bushing (15) is sleeved on the outer side of the front bearing structure, the front pivot bearing outer ring pressure ring (16) is arranged in the front pivot bearing bushing (15) and is located in front of the bearing structure, the non-contact sealing ring (17) is located in front of the front pivot bearing bushing (15) and is tightly attached to the front pivot bearing bushing (15), the rear end convex ring of the non-contact sealing ring (17) presses against the front pivot bearing outer ring pressure ring (16) and is inserted into the front pivot bearing bushing (15); an axial gap and a radial gap are left between the non-contact sealing ring (17) and the shaft head flange (26); A second channel (15-1) communicating with the adjacent first channel (30-1) is provided on the upper portion of the front pivot bearing bushing (15); a third channel (17-1) communicating with the second channel (15-1) is provided on the non-contact sealing ring (17); an outlet end of the third channel (17-1) faces the radial gap between the non-contact sealing ring (17) and the shaft head flange (26); The rear pivot bearing bushing (11) and the blind cover (13) are fixed to the rear end of the gear box (18) in sequence from front to back, the rear pivot bearing bushing (11) is sleeved on the outer side of the bearing structure at the rear end, the rear pivot bearing outer ring pressure ring (12) is arranged in the rear pivot bearing bushing (11) and is located behind the bearing structure, and the front end convex ring of the blind cover (13) presses against the rear pivot bearing outer ring pressure ring (12) and is inserted into the rear pivot bearing bushing (11); A channel six (11-1) communicating with an adjacent channel one (30-1) is provided on the upper portion of the rear pivot bearing bushing (11), and a channel seven (13-1) communicating with the channel six (11-1) and the outside is provided on the cover (13).

5. A high-speed shaft system with air-assisted sealing that does not require an external air source according to claim 4, characterized in that: The non-contact sealing ring (17) is provided with a channel four (17-2) connecting the channel three (17-1) with the outside world; The non-contact sealing ring (17) is provided with a channel five (17-3) connecting the channel three (17-1) with the outside, and a plug is connected to the channel five (17-3).

6. A high-speed shaft system with air-assisted sealing that does not require an external air source according to claim 5, characterized in that: A bearing outer ring oil spraying spacer (14) is provided between two main shaft bearings (24) of each bearing structure, an oil groove is left on the outer ring of the bearing outer ring oil spraying spacer (14), an oil port 1 (15-3) arranged on the front fulcrum bearing bushing (15) is provided at the bottom of the second channel (15-1), the second channel (15-1) is communicated with the oil port 1 (15-3), and the oil port 1 (15-3) is located above the oil groove of the adjacent bearing outer ring oil spraying spacer (14); The bottom of the channel six (11-1) is provided with an oil port two (11-3) arranged on the rear pivot bearing bushing (11), the channel six (11-1) is connected with the oil port two (11-3), and the oil port two (11-3) is located above the oil groove of the adjacent bearing outer ring oil injection spacer ring (14).

7. A high-speed shaft system with air-assisted sealing that does not require an external air source according to claim 6, characterized in that: A notch 1 (16-2) is provided at the front lower part of the front pivot bearing outer ring pressure ring (16), and a channel 8 (15-2) is provided at the lower part of the front pivot bearing bushing (15) for connecting the notch 1 (16-2) and the inner space of the gear box (18); A notch 2 (12-1) is provided at the rear lower portion of the rear pivot bearing outer ring pressure ring (12), and a channel 9 (11-2) is provided at the lower portion of the rear pivot bearing bushing (11) for connecting the notch 2 (12-1) with the internal space of the gear box (18).

8. A high-speed shaft system with air-assisted sealing that does not require an external air source according to claim 7, characterized in that: The non-contact sealing ring (17) is provided with a channel ten (17-4) which is in communication with the channel nine (11-2), and the outlet end of the channel ten (17-4) faces the radial gap between the non-contact sealing ring (17) and the shaft head flange (26).

9. A high-speed shaft system with air-assisted sealing that does not require an external air source according to claim 8, characterized in that: An oil slinger (28) is provided between the shaft head flange (26) and the adjacent bearing assembly and rotates synchronously with the gear shaft (21). The oil slinger (28) is located inside the front pivot bearing outer ring pressure ring (16). An oil port three (16-1) is provided on the upper part of the front pivot bearing outer ring pressure ring (16). An oil port four (15-4) corresponding to the oil port three (28-1) and connected to the channel two (15-1) is provided on the front pivot bearing bushing (15).

10. The high-speed shaft system with air-assisted sealing that does not require an external air source according to claim 8, characterized in that: N oil return sieve holes (30-2) with a diameter of D are arranged at the lower part of the air induced pipe (30), and the oil return sieve holes (30-2) allow the droplets generated by the collected oil-gas mixture to flow back into the gear box (18).

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