CN111637074B

CN111637074B - Sealing device of numerical control fan

Info

Publication number: CN111637074B
Application number: CN202010521001.6A
Authority: CN
Inventors: 傅强; 杨从贵; 管照正; 彭拥军; 王晓松; 周玉红; 徐经存
Original assignee: Anhui Lu Feng Fan Co ltd
Current assignee: Anhui Lu Feng Fan Co ltd
Priority date: 2020-06-10
Filing date: 2020-06-10
Publication date: 2021-09-24
Anticipated expiration: 2040-06-10
Also published as: CN111637074A

Abstract

The invention discloses a sealing device of a numerical control fan, belonging to the technical field of fan sealing, comprising a machine shell, wherein the surface of the machine shell is clamped with a bearing box, a bearing is arranged in the bearing box, a main shaft is sleeved in the bearing, the surface of the main shaft is respectively sleeved with a first sealing sheet and a second sealing sheet, and the opposite surfaces of the second sealing sheet and the first sealing sheet are fixedly connected through a spring. According to the invention, through the designed mutual matching among the first sealing sheet, the second sealing sheet, the spring, the sealing box cover, the oil retainer, the oil receiving ring, the sealing element, the first fan flange, the second fan flange, the inert gas sealing ring, the first one-way valve and the second one-way valve, the lubricating oil in the oil cavity can be prevented from leaking towards the direction of the machine shell, the three sealing modes of mechanical sealing, oil sealing and gas sealing interact and influence each other, the sealing effect of the fan in long-time operation can be ensured, and the leakage phenomenon is avoided.

Description

Sealing device of numerical control fan

Technical Field

The invention belongs to the technical field of fan sealing, and particularly relates to a sealing device of a numerical control fan.

Background

The fan is a driven fluid machine which increases the pressure of gas and discharges the gas by means of input mechanical energy. The blower is a Chinese habit abbreviation for gas compression and gas conveying machinery, and the blower generally comprises a ventilator, a blower and a wind driven generator.

Fans are widely used for ventilation, dust exhaust and cooling of factories, mines, tunnels, cooling towers, vehicles, ships and buildings, and for ventilation and draught of boilers and industrial furnaces and kilns; cooling and ventilation in air conditioning equipment and household appliances; drying and selecting grain, wind tunnel wind source and air cushion boat inflating and propelling.

The sealing performance of the numerical control fan is one of the important indexes of the operation reliability, especially in the occasions of conveying toxic, harmful, inflammable, explosive or noble gases, if the sealing is not good, a large amount of noble gases are leaked, and more serious environment pollution is caused, however, at present, a plurality of bearing boxes of the numerical control fan generate oil leakage phenomenon due to unreasonable sealing structure, which not only pollutes the surrounding working environment, but also causes poor lubrication to damage the bearing in serious cases, and the sealing device for the numerical control fan usually adopts a single mechanical sealing mode, an oil sealing mode or an air sealing mode and the like for sealing, and is easy to damage after long-time use, so that a sealing device for the numerical control fan is urgently needed in the market at present stage to solve the problems.

Disclosure of Invention

The invention aims to: the sealing device of the numerical control fan is provided for solving the problems that at present, a plurality of bearing boxes of the numerical control fan generate oil leakage phenomenon due to unreasonable sealing structures, not only can pollute surrounding working environments, but also can cause poor lubrication to damage bearings in serious cases, and the sealing device for the numerical control fan is sealed by adopting single mechanical sealing, oil sealing or air sealing and the like generally and is easy to damage after being used for a long time.

In order to achieve the purpose, the invention adopts the following technical scheme:

a sealing device of a numerical control fan comprises a machine shell, wherein a bearing box is clamped on the surface of the machine shell, a bearing is arranged in the bearing box, a main shaft is sleeved in the bearing, a first sealing sheet and a second sealing sheet are respectively sleeved on the surface of the main shaft, the opposite surface of the second sealing sheet and the first sealing sheet is fixedly connected through a spring, a sealing box cover is sleeved on the outer sides of the first sealing sheet and the second sealing sheet, the surface of part of the sealing box cover is sleeved on the inner side wall of the bearing box, an oil baffle ring and an oil receiving ring are respectively and fixedly connected on the inner side wall of the sealing box cover, an oil cavity is enclosed by the oil receiving ring, the oil baffle ring, the first sealing sheet, the second sealing sheet and the inner side of the sealing box cover, the surfaces of the sealing box cover and the bearing box are both sleeved on the inner side wall of a sealing sleeve, and a first, the second fan flange and the first fan flange are both sleeved on the surface of the main shaft, the opposite surfaces of the second fan flange and the first fan flange are fixedly connected through an inert gas sealing ring, and the inert gas sealing ring is sleeved on the surface of the main shaft.

As a further description of the above technical solution:

the surface cover of main shaft is equipped with the fastening lock mother to the fastening lock mother is close to the second gasket, second gasket and first gasket all adopt polytetrafluoroethylene material processing to form.

As a further description of the above technical solution:

the cross section of the sealing box cover in a front view is in a T-shaped structure which rotates ninety degrees in the clockwise direction, and the side surface of the sealing box cover is detachably connected with the side surface close to the bearing box through a first fastening screw.

As a further description of the above technical solution:

and a sealing element is embedded in the inner side wall of the sealing box cover and is sleeved on the surface of the main shaft, and the sealing element is made of a composite material.

As a further description of the above technical solution:

the surface joint of seal cover, bearing box and sealed case lid has same root oiling pipe, the one end of oiling pipe is linked together with the inside of oil pocket, the other end of oiling pipe is provided with lubricating grease oiling valve.

As a further description of the above technical solution:

the side joint of first fan flange has first connecting pipe, the one end joint in the side of sealed case lid that first connecting pipe kept away from first fan flange to the tip of first connecting pipe is linked together with the inside of oil pocket, be provided with first check valve on the first connecting pipe.

As a further description of the above technical solution:

the side joint of first fan flange has the second connecting pipe, the one end joint in the side of sealed case lid that first fan flange was kept away from to the second connecting pipe to the tip of second connecting pipe is linked together with the inside of oil pocket, be provided with the second check valve on the second connecting pipe to the piston has been cup jointed in the second connecting pipe, and correspond the first spacing collar of position difference fixedly connected with and the second spacing collar of piston on the second connecting pipe inside wall, and second spacing collar and first spacing collar are located the both sides of piston respectively.

As a further description of the above technical solution:

the position of the surface of the sealing sleeve corresponding to the inert gas sealing ring is clamped with a connecting air pipe, one end of the connecting air pipe, far away from the sealing sleeve, is provided with a barometer, the side surface of the connecting air pipe is clamped with an inflation pipe, and one end of the inflation pipe, far away from the connecting air pipe, is provided with an inflation valve.

As a further description of the above technical solution:

the surface of the sealing sleeve is fixedly connected with a connecting flange, an elastic sealing ring is arranged between the connecting flange and the casing, and the opposite surface of the casing and the connecting flange is detachably connected through a second fastening screw.

As a further description of the above technical solution:

the motor is characterized in that one end of the main shaft is fixedly connected with an impeller, the impeller is located inside the shell, the other end of the main shaft is fixedly connected with the end part of the motor output shaft, the bottom of the motor body is fixedly connected with the top of the base through a motor base, and the top of the base is fixedly connected with the bottom of the shell through a fan base.

In summary, due to the adoption of the technical scheme, the invention has the beneficial effects that:

1. according to the invention, through the designed mutual matching among the first sealing sheet, the second sealing sheet, the spring, the sealing box cover, the oil retainer, the oil receiving ring, the sealing element, the first fan flange, the second fan flange, the inert gas sealing ring, the first one-way valve and the second one-way valve, the lubricating oil in the oil cavity can be prevented from leaking towards the direction of the machine shell, the three sealing modes of mechanical sealing, oil sealing and gas sealing interact and influence each other, the sealing effect of the fan in long-time operation can be ensured, and the leakage phenomenon is avoided.

2. According to the invention, the first sealing piece and the second sealing piece are made of polytetrafluoroethylene sealing materials and have strong toughness and lubricity, so that the spindle is pressed under the pressure in the machine shell, the sealing performance is good, the designed fastening nut is used for limiting the moving range of the first sealing piece and the second sealing piece, and the sealing effect of the first sealing piece and the second sealing piece can be improved.

3. In the invention, through the designed connecting flange, the elastic sealing ring and the second fastening nut, the elastic sealing ring is used as a connecting medium between the connecting flange and the machine shell, can play a role in buffering and damping, so that the vibration on the surface of the machine shell can play a role in weakening when being radiated to the sealing sleeve to a certain extent, the stability of the sealing sleeve can be improved, by the designed oil filling pipe and the grease filling valve, the oil filling pipe is used as a medium for communicating the oil cavity with the outside, so that the grease can be conveniently filled into the oil cavity from the outside, the lubricating grease injection valve is used for controlling the on-off of the end part of the oil injection pipe so as to avoid the leakage of the lubricating grease in the oil cavity, through the designed barometer, the inflation tube and the inflation valve, the connecting air tube is used as a communication medium between the barometer and the inert gas storage cavity, the pressure in the inert gas sealed cavity can be measured, and the inflation valve can be used for controlling the on-off of the inflation tube.

Drawings

Fig. 1 is a schematic three-dimensional structure diagram of a sealing device of a numerical control fan according to the present invention;

FIG. 2 is a schematic cross-sectional structure view of a sealing sleeve of a sealing device of a numerical control fan according to the present invention from the left;

FIG. 3 is an enlarged schematic structural view of a sealing device A of the numerical control fan according to the present invention;

FIG. 4 is an enlarged schematic structural diagram of a sealing device B of a numerical control fan according to the present invention;

fig. 5 is a schematic cross-sectional view of a front view of a second connecting pipe of the sealing device of the numerical control fan according to the present invention.

Illustration of the drawings:

1. a housing; 2. a bearing housing; 3. a bearing; 4. a main shaft; 5. an impeller; 6. a first sealing sheet; 7. a spring; 8. a second sealing sheet; 9. fastening a lock nut; 10. sealing the box cover; 11. an oil slinger; 12. an oil ring is connected; 13. a seal member; 14. an oil filling pipe; 15. a grease filling valve; 16. a first fan flange; 17. a second fan flange; 18. an inert gas seal ring; 19. a first connecting pipe; 20. a first check valve; 21. a first fastening screw; 22. a connecting flange; 23. an elastic sealing ring; 24. a second fastening screw; 25. sealing sleeves; 26. connecting an air pipe; 27. a barometer; 28. an inflation tube; 29. an inflation valve; 30. a second connecting pipe; 31. a second one-way valve; 32. an oil chamber; 33. a motor; 34. a motor base; 35. a fan base; 36. a base; 37. a piston; 38. a first spacing collar; 39. and a second limiting ring.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to fig. 1-5, the present invention provides a technical solution: a sealing device of a numerical control fan comprises a machine shell 1, a bearing box 2 is clamped on the surface of the machine shell 1, a bearing 3 is arranged in the bearing box 2, a main shaft 4 is sleeved in the bearing 3, a first sealing sheet 6 and a second sealing sheet 8 are respectively sleeved on the surface of the main shaft 4, the first sealing sheet 6 and the second sealing sheet 8 are designed, the first sealing sheet 6 and the second sealing sheet 8 arranged between a sealing box cover 10 and the main shaft 4 are movably sleeved on the surface of the main shaft 4 to form a staggered sealing structure, gas conveyed in the machine shell 1 and lubricating oil injected in an oil cavity 32 can be prevented from leaking to a certain extent, the sealing performance is stable, the service life is long, the opposite surfaces of the second sealing sheet 8 and the first sealing sheet 6 are fixedly connected through springs 7, the sealing box cover 10 is sleeved on the outer sides of the first sealing sheet 6 and the second sealing sheet 8, and the surface of a part of the sealing box cover 10 is sleeved on the inner side wall of the bearing box 2, fixedly connected with oil slinger 11 and oil receiving ring 12 respectively on the inside wall of sealed case lid 10, oil receiving ring 12, oil slinger 11, first gasket 6, the inboard of second gasket 8 and sealed case lid 10 encloses into an oil pocket 32, through the oil pocket 32 of design, oil receiving ring 12, oil slinger 11, first gasket 6, the inboard of second gasket 8 and sealed case lid 10 encloses into an oil pocket 32 labyrinth structure, it can hinder a small amount of gas of leaking through first gasket 6 and second gasket 8 department to pour into lubricating oil into in the oil pocket 32, play the sealed effect of oil blanket, the surface of sealed case lid 10 and bearing box 2 all cup joints on the inside wall of sealed cover 25, and cup jointed first fan flange 16 and second fan flange 17 respectively on the inside wall of sealed cover 25, second fan flange 17 and first fan flange 16 all cup joint the surface of main shaft 4, and the opposite face of second fan flange 17 and first fan flange 16 passes through inert gas sealing ring 18 fixed connection sealing washer Then, the inert gas sealing ring 18 is sleeved on the surface of the main shaft 4, through the designed interaction of the inert gas in the inert gas storage cavity enclosed by the first fan flange 16, the second fan flange 17 and the inert gas sealing ring 18, the first fan flange 16, the second fan flange 17, the inert gas sealing ring 18 and the sealing sleeve 25, when the gas conveyed in the casing 1 leaks, the gas pressure in the oil cavity 32 is increased and is larger than the gas pressure in the inert gas storage cavity, the first one-way valve 20 is opened, so that the two sides of the lubricating oil in the oil cavity 32 are stressed, the effect of constant pressure can be achieved, the lubricating oil and the gas are prevented from leaking out, when the gas pressure in the casing 1 is reduced, the gas pressure in the oil cavity 32 is gradually reduced, the second one-way valve 31 is opened, the piston 37 is pulled to move towards the direction of the oil cavity 32, because the inert gas storage cavity is a sealing structure, a large force is required to pull piston 37, and therefore, the lubricating oil in oil chamber 32 is prevented from leaking in the direction of casing 1.

Specifically, as shown in fig. 4, the surface cover of main shaft 4 is equipped with the female 9 of fastening lock, fastening lock through the design is female 9, be used for prescribing a limit to the home range of first gasket 6 and second gasket 8, can improve the sealed effect of first gasket 6 and second gasket 8, and fastening lock is female 9 near second gasket 8, second gasket 8 and first gasket 6 all adopt polytetrafluoroethylene material processing to form, first gasket 6 and second gasket 8 through the design, first gasket 6 and second gasket 8 all adopt polytetrafluoroethylene sealing material, toughness and lubricity stronger, make and compress tightly main shaft 4 under casing 1 internal pressure, the leakproofness is good.

Specifically, as shown in fig. 3, the front cross-sectional shape of the seal cover 10 is a T-shaped structure rotated ninety degrees in the clockwise direction, and the side surface of the seal cover 10 adjacent to the bearing housing 2 is detachably connected by a first fastening screw 21.

Specifically, as shown in fig. 3, a sealing element 13 is embedded on an inner side wall of the sealed box cover 10, the sealing element 13 is sleeved on the surface of the main shaft 4, and the sealing element 13 is made of a composite material.

Specifically, as shown in fig. 3, the surface joint of seal cover 25, bearing box 2 and sealed case lid 10 has same oiling pipe 14, oiling pipe 14's one end is linked together with the inside of oil pocket 32, oiling pipe 14's the other end is provided with grease oiling valve 15, oiling pipe 14 and grease oiling valve 15 through the design, oiling pipe 14 is as the medium that switches on of oil pocket 32 with the external world, be convenient for pour into lubricating grease into to oil pocket 32 from the outside, and grease oiling valve 15 is used for controlling the break-make of oiling pipe 14 tip, avoid the lubricating grease in the oil pocket 32 to take place to leak.

Specifically, as shown in fig. 3, a first connecting pipe 19 is clamped on a side surface of the first fan flange 16, one end of the first connecting pipe 19, which is far away from the first fan flange 16, is clamped on a side surface of the sealed case cover 10, an end portion of the first connecting pipe 19 is communicated with the inside of the oil chamber 32, and a first check valve 20 is arranged on the first connecting pipe 19.

Specifically, as shown in fig. 3, a second connecting pipe 30 is clamped to a side surface of the first fan flange 16, one end of the second connecting pipe 30, which is far away from the first fan flange 16, is clamped to a side surface of the sealed case cover 10, an end portion of the second connecting pipe 30 is communicated with an inside of the oil chamber 32, a second one-way valve 31 is arranged on the second connecting pipe 30, a piston 37 is sleeved in the second connecting pipe 30, a first limiting ring 38 and a second limiting ring 39 are fixedly connected to positions, corresponding to the piston 37, on an inner side wall of the second connecting pipe 30, and the second limiting ring 39 and the first limiting ring 38 are respectively located on two sides of the piston 37.

Specifically, as shown in fig. 3, a connecting air tube 26 is clamped on the surface of the sealing sleeve 25 at a position corresponding to the inert gas sealing ring 18, an air pressure gauge 27 is arranged at one end of the connecting air tube 26 far away from the sealing sleeve 25, an inflation tube 28 is clamped on the side surface of the connecting air tube 26, an inflation valve 29 is arranged at one end of the inflation tube 28 far away from the connecting air tube 26, the connecting air tube 26 serves as a conduction medium between the air pressure gauge 27 and the inert gas storage cavity through the designed air pressure gauge, inflation tube 28 and inflation valve 29, so that the air pressure in the inert gas sealing cavity can be measured, and the inflation valve 29 can be used for controlling the on-off of the inflation tube 28.

Specifically, as shown in fig. 3, the surface of the sealing sleeve 25 is fixedly connected with a connecting flange 22, an elastic sealing ring 23 is arranged between the connecting flange 22 and the casing 1, the casing 1 is detachably connected with the opposite surface of the connecting flange 22 through a second fastening screw 24, the connecting flange 22 is designed, the elastic sealing ring 23 and a second fastening nut are designed, the elastic sealing ring 23 serves as a connecting medium between the connecting flange 22 and the casing 1, the effect of buffering and damping can be achieved, the vibration on the surface of the casing 1 can be weakened to a certain extent when being radiated to the sealing sleeve 25, and the stability of the sealing sleeve 25 can be improved.

Specifically, as shown in fig. 2, one end of the main shaft 4 is fixedly connected with the impeller 5, the impeller 5 is located inside the casing 1, the other end of the main shaft 4 is fixedly connected with the end of the output shaft of the motor 33, the bottom of the body of the motor 33 is fixedly connected with the top of the base 36 through the motor base 34, and the top of the base 36 is fixedly connected with the bottom of the casing 1 through the fan base 35.

The working principle is as follows: when in use, the first sealing sheet 6 and the second sealing sheet 8 arranged between the sealing case cover 10 and the main shaft 4 are movably sleeved on the surface of the main shaft 4 to form a staggered sealing structure, which can prevent the gas conveyed in the casing 1 and the lubricating oil injected in the oil cavity 32 from leaking to a certain extent, the sealing performance is stable, the service life is long, the oil receiving ring 12, the oil baffle ring 11, the first sealing sheet 6, the second sealing sheet 8 and the sealing case cover 10 enclose an oil cavity 32 labyrinth structure, the lubricating oil injected in the oil cavity 32 can block a small amount of gas leaked through the first sealing sheet 6 and the second sealing sheet 8, the sealing effect of an oil seal is achieved, the oil seal interacts with the inert gas in the inert gas storage cavity enclosed by the first fan flange 16, the second fan flange 17, the inert gas sealing ring 18 and the sealing case 25, when the gas conveyed in the casing 1 leaks, the air pressure in the oil cavity 32 can be increased and is larger than the air pressure in the inert gas storage cavity, the first check valve 20 is opened, so that the two sides of the lubricating oil in the oil cavity 32 are stressed, the effect of constant pressure can be achieved, the lubricating oil and the gas are prevented from leaking, when the air pressure in the shell 1 is reduced, the air pressure in the oil cavity 32 is gradually reduced, the second check valve 31 is opened and pulls the piston 37 to move towards the direction of the oil cavity 32, because the inert gas storage cavity is a sealing structure, the pulling piston 37 needs larger acting force, so that the lubricating oil in the oil cavity 32 can be prevented from leaking towards the direction of the shell 1, three sealing modes of mechanical sealing, oil sealing and gas sealing are interacted and mutually influenced, the sealing effect of the fan in long-time operation can be ensured, the leakage phenomenon is avoided, the elastic sealing ring 23 is used as a connecting medium between the connecting flange 22 and the shell 1, can play buffering absorbing effect, can play certain weakening effect when making the vibrations on casing 1 surface outwards radiate to seal cover 25, alright improve seal cover 25's stability, oiling pipe 14 is as the medium that switches on of oil pocket 32 and external world, be convenient for pour into lubricating grease into oil pocket 32 from the outside into, and lubricating grease oiling valve 15 is used for controlling the break-make of oiling pipe 14 tip, avoid lubricating grease in oil pocket 32 to take place to leak, connect trachea 26 as the medium that switches on between barometer 27 and the inert gas storage chamber, can measure the atmospheric pressure volume in the inert gas seal chamber, and inflation valve 29 can be used to control the break-make of gas tube 28.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be able to cover the technical scope of the present invention and the equivalent alternatives or modifications according to the technical solution and the inventive concept of the present invention within the technical scope of the present invention.

Claims

1. The utility model provides a sealing device of numerical control fan, includes casing (1), its characterized in that, the surface joint of casing (1) has bearing box (2), be provided with bearing (3) in bearing box (2), main shaft (4) have been cup jointed in bearing (3), the surface of main shaft (4) is overlapped respectively and is equipped with first gasket (6) and second gasket (8), and second gasket (8) pass through spring (7) fixed connection with the opposite face of first gasket (6), the outside cover of first gasket (6) and second gasket (8) is equipped with sealed case lid (10), and the surface of part sealed case lid (10) cup joints on the inside wall of bearing box (2), fixedly connected with oil scraper ring (11) and oil receiving ring (12) respectively on the inside wall of sealed case lid (10), oil receiving ring (12), oil scraper ring (11), An oil cavity (32) is defined by the inner sides of the first sealing sheet (6), the second sealing sheet (8) and the sealing case cover (10), the surfaces of the sealing case cover (10) and the bearing case (2) are sleeved on the inner side wall of the sealing sleeve (25), a first fan flange (16) and a second fan flange (17) are respectively sleeved on the inner side wall of the sealing sleeve (25), the second fan flange (17) and the first fan flange (16) are both sleeved on the surface of the main shaft (4), opposite surfaces of the second fan flange (17) and the first fan flange (16) are fixedly connected through an inert gas sealing ring (18), and the inert gas sealing ring (18) is sleeved on the surface of the main shaft (4);

a first connecting pipe (19) is clamped on the side surface of the first fan flange (16), one end, far away from the first fan flange (16), of the first connecting pipe (19) is clamped on the side surface of the sealed box cover (10), the end part of the first connecting pipe (19) is communicated with the inside of the oil cavity (32), and a first one-way valve (20) is arranged on the first connecting pipe (19);

a second connecting pipe (30) is clamped on the side face of the first fan flange (16), one end, far away from the first fan flange (16), of the second connecting pipe (30) is clamped on the side face of the sealed box cover (10), the end portion of the second connecting pipe (30) is communicated with the inside of the oil cavity (32), a second one-way valve (31) is arranged on the second connecting pipe (30), a piston (37) is sleeved in the second connecting pipe (30), a first limiting ring (38) and a second limiting ring (39) are fixedly connected to the inner side wall of the second connecting pipe (30) at positions corresponding to the piston (37) respectively, and the second limiting ring (39) and the first limiting ring (38) are located on two sides of the piston (37) respectively;

the position joint that seal cover (25) surface corresponds inert gas sealing washer (18) has connecting trachea (26), it is provided with barometer (27) to connect trachea (26) one of keeping away from seal cover (25) one end, the side joint of connecting trachea (26) has gas tube (28) to gas tube (28) keep away from the one end of connecting trachea (26) and are provided with inflation valve (29).

2. The sealing device of the numerical control fan according to claim 1, wherein a fastening locking nut (9) is sleeved on the surface of the main shaft (4), the fastening locking nut (9) abuts against the second sealing sheet (8), and the second sealing sheet (8) and the first sealing sheet (6) are both made of polytetrafluoroethylene materials.

3. The sealing device of the numerical control fan according to claim 2, wherein the cross-sectional shape of the sealing box cover (10) in front view is a T-shaped structure rotated ninety degrees in a clockwise direction, and the side surface of the sealing box cover (10) close to the side surface of the bearing box (2) is detachably connected through the first fastening screw (21).

4. The sealing device of the numerical control fan according to claim 3, wherein a sealing element (13) is embedded on the inner side wall of the sealing box cover (10), the sealing element (13) is sleeved on the surface of the main shaft (4), and the sealing element (13) is made of a composite material.

5. The sealing device of the numerical control fan as claimed in claim 4, wherein the same oil injection pipe (14) is clamped on the surfaces of the sealing sleeve (25), the bearing box (2) and the sealing box cover (10), one end of the oil injection pipe (14) is communicated with the inside of the oil cavity (32), and the other end of the oil injection pipe (14) is provided with a lubricating grease injection valve (15).

6. The sealing device of the numerical control fan according to claim 5, wherein a connecting flange (22) is fixedly connected to the surface of the sealing sleeve (25), an elastic sealing ring (23) is arranged between the connecting flange (22) and the casing (1), and the opposite surfaces of the casing (1) and the connecting flange (22) are detachably connected through a second fastening screw (24).

7. The sealing device of the numerical control fan according to claim 6, wherein one end of the main shaft (4) is fixedly connected with the impeller (5), the impeller (5) is located inside the casing (1), the other end of the main shaft (4) is fixedly connected with the end of the output shaft of the motor (33), the bottom of the body of the motor (33) is fixedly connected with the top of the base (36) through the motor base (34), and the top of the base (36) is fixedly connected with the bottom of the casing (1) through the fan base (35).