Magnetic fluid sealing transmission device with high sealing performance

Abstract

The invention discloses a magnetofluid sealing transmission device with high sealing performance, which comprises a transmission device shell connected with a vacuum cavity and a transmission device main shaft arranged in the transmission device shell, and an integrated multi-stage magnetic pole structure is arranged at one end, facing the vacuum cavity, of the transmission device main shaft. A bearing assembly is arranged at the end, away from the vacuum cavity, of the transmission device main shaft, and a self-sealing structure is formed between the integrated multi-stage magnetic pole structure and the transmission device shell. An integrated multi-stage magnetic pole structure is adopted, a transmission device shell and a transmission device main shaft are sealed through knife edge flanges or metal sealing rings, a magnetic sealing area is arranged at one end of a vacuum cavity, a bearing assembly is arranged at the end away from the vacuum cavity, high sealing performance is achieved, the use requirements of high-vacuum and high-pressure-difference environments can be met, and the service life of the transmission device is prolonged. And the high-permeability gas can be effectively prevented from breaking the vacuum, so that the high-permeability gas sealing device can be widely applied to environment working conditions with the high-permeability gas.

Description

Technical Field

[0001] The invention relates to the technical field of magnetic fluid sealing, in particular to a magnetic fluid sealing transmission device with high sealing performance. Background Art

[0002] The current magnetic fluid sealing device for vacuum sealing mainly forms a closed magnetic line of force through the magnetic pole, magnetic block, magnetic fluid and main shaft under the magnetic action of the magnetic block, and forms dynamic sealing rings under the action of the magnetic field of the magnetic fluid and the magnetic block. The rotating main shaft and the magnetic pole are sealed by this dynamic sealing ring.

[0003] A magnetic shoe in a magnetic fluid seal structure can ensure resistance to a pressure difference of 0.15-0.25 atmospheres. Usually, a safety factor of 1.5 to 2 times is added during design. The greater the pressure difference, the more teeth are needed.

[0004] At the same time, the current prior art uses an O-ring on the sealing device housing to seal with the vacuum chamber, an O-ring is used on each magnetic pole to seal with the housing, and the magnetic poles are separated and individually arranged. The magnetic fluid sealing main shaft seals the external transmission shaft through the O-ring on the main shaft.

[0005] The existing sealing device has the following problems: the O-ring cannot seal high vacuum, high pressure difference and high permeability gas, that is, it cannot meet the sealing conditions of high vacuum and high pressure difference, and cannot meet the effective sealing of high permeability gas, such as inert gas, etc. Inert gas such as helium has high permeability, and high permeability means that the gas has a small molecular weight and is often used as a helium leak detector to detect the sealing. The O-ring cannot prevent the penetration of inert gas such as helium, so that the sealing effect of the sealing device cannot meet the design requirements.

[0006] In the current technical solution for magnetic fluid sealing, the magnetic poles are independent parts and there is no seal between the two poles. Once the gas breaks through a sealing ring, it can leak from the magnetic block between the two poles to the next pole. It is also impossible to achieve sealing for high vacuum, high pressure difference, and high permeability gas.

[0007] Therefore, in view of the above problems in the prior art, a magnetic fluid sealing transmission device is specially designed which can meet the sealing requirements under high vacuum and high pressure difference conditions and also has high sealing performance for sealing high permeability gases. Summary of the invention

[0008] The purpose of the present invention is to solve the problems that the existing magnetic fluid sealing devices for vacuum sealing cannot meet the sealing requirements under high vacuum and high pressure difference conditions, and cannot achieve sealing of high permeability gases, and to provide a magnetic fluid sealing transmission device with a simple structure and good sealing effect, which can achieve the sealing requirements under high vacuum and high pressure difference conditions and can achieve effective sealing of high permeability inert gases.

[0009] The technical solution adopted by the present invention to achieve its invention purpose is: a magnetic fluid sealed transmission device with high sealing performance, comprising a transmission device housing connected to a vacuum cavity and a transmission device main shaft arranged inside the transmission device housing, an integrated multi-stage magnetic pole structure is arranged at one end of the transmission device main shaft facing the vacuum cavity, and a bearing assembly is arranged on the transmission device main shaft at one end away from the vacuum cavity, and a self-sealing structure is formed between the integrated multi-stage magnetic pole structure and the transmission device housing. The magnetic fluid sealed transmission device with high sealing performance is newly designed for the existing magnetic fluid sealed transmission device, the magnetic sealing area is arranged at one end of the vacuum cavity, and the magnetic fluid assembly is arranged as an integrated multi-stage magnetic pole structure, the integrated multi-stage magnetic pole structure forms a self-sealing structure between it and the transmission device housing, and solves the problem that a single magnetic pole is arranged in the prior art, there is no seal between the magnetic poles, under high vacuum, high pressure difference conditions, and high permeability gas application conditions, it is easy to be broken by high pressure or high permeability gas, and effective sealing cannot be achieved, there is no gap between the magnetic poles of the integrated multi-stage magnetic pole structure, and high permeability inert gas cannot penetrate through the gap, and good sealing performance is achieved. At the same time, the bearing assembly is arranged in a cantilever structure at one end away from the vacuum cavity. The bearing assembly is no longer arranged on both sides of the magnetic area in a supporting beam type, but is arranged in a cantilever structure with the vacuum cavity. There is no bearing assembly on one side of the vacuum cavity. The gas generated by the grease of the bearing assembly during operation will not enter the vacuum cavity to affect the vacuum degree. At the same time, since the bearing assembly is arranged away from the vacuum cavity and there is an integrated multi-stage magnetic pole structure in the middle for sealing, the gas will not break the seal of the integrated multi-stage magnetic pole structure and enter the vacuum cavity, which solves the problem that the existing bearing is arranged at both ends of the magnetic fluid, and the gas generated by the grease will break the vacuum and enter the inside of the vacuum cavity, thereby causing poor sealing, etc., and a stable support transmission is formed between the bearing assembly and the transmission shaft, and the force transmission effect is better. Moreover, the structure is simple and the sealing effect is good, which can meet the sealing requirements under high vacuum and high pressure difference conditions, and can also achieve effective sealing of high permeability inert gas.

[0010] Preferably, the integrated multi-stage magnetic pole structure comprises a multi-stage magnetic pole body and a plurality of magnetic blocks arranged in an integrated structure, the multi-stage magnetic pole body is provided with a plurality of N poles and S poles, a magnetic block slot is provided between the N poles and the S poles, and the magnetic block is inserted inside the magnetic block slot. The integrated multi-stage magnetic pole structure comprises an integrally formed multi-stage magnetic pole body, a plurality of N poles and S poles are provided on the multi-stage magnetic pole body, a plurality of magnetic block slots are provided on the multi-stage magnetic pole body, and magnetic blocks are inserted inside the magnetic block slots, thereby forming a multi-stage magnetic pole design, and compared with a single magnetic pole, the multi-stage magnetic pole achieves a higher sealing performance.

[0011] Preferably, a magnetic shoe and magnetic fluid forming a magnetic fluid sealing structure are arranged between the integrated multi-stage magnetic pole structure and the main shaft of the transmission device. The magnetic shoe and magnetic fluid are arranged to form a magnetic fluid sealing structure, thereby forming a sealing structure with high sealing performance.

[0012] Preferably, the magnetic block slot is provided on the outer wall of the multi-stage magnetic pole body, and the inner wall of the multi-stage magnetic pole body is an integrated sleeve structure. The magnetic block slot is provided to facilitate the insertion of the magnetic block to form an integrated multi-stage magnetic pole structure and realize a magnetic fluid sealing structure with high sealing performance. The inner wall of the multi-stage magnetic pole body is an integrated structure, and the magnetic fluid sealing performance is better.

[0013] Preferably, a magnetic fluid leakage prevention baffle is provided at one end of the transmission device main shaft facing the vacuum chamber. The magnetic fluid leakage prevention baffle is provided to block the magnetic fluid and prevent the magnetic fluid from being thrown out during use.

[0014] Preferably, the integrated multi-stage magnetic pole structure is provided with an anti-deformation welding sealing structure, and the anti-deformation welding sealing structure is arranged at one end of the integrated multi-stage magnetic pole structure facing the vacuum side. The anti-deformation welding sealing structure is provided to facilitate the welding of the integrated multi-stage magnetic pole structure and the transmission device housing, while avoiding welding deformation during the welding process, which affects the sealing performance. The provision of the anti-deformation welding structure can realize the welding connection between the integrated multi-stage magnetic pole structure and the transmission device housing, and adopts direct sealing by the weld seam, which solves the problem that the welding connection cannot be realized in the prior art, and the sealing performance is poor by the O-ring sealing, and the penetration of high-permeability inert gas cannot be avoided.

[0015] Preferably, the anti-deformation welding sealing structure includes a welding body integrally arranged with the integrated multi-stage magnetic pole structure, an anti-deformation welding outer groove is arranged on the outer wall of the welding body, an anti-deformation welding inner groove is arranged on the inner wall of the welding body, and an anti-deformation welding end groove is arranged on the end face of the welding body. The welding body is integrally arranged with the integrated multi-stage magnetic pole structure, which does not affect the formation of the magnetic sealing structure and facilitates the welding connection between the welding body and the transmission device housing. The anti-deformation welding outer groove, the anti-deformation welding inner groove and the anti-deformation welding end groove are all arranged to prevent deformation during the welding process between the welding body and the transmission device housing to avoid affecting the sealing performance.

[0016] Preferably, a shell deformation prevention welding sealing structure is provided on the end surface where the transmission device shell and the welding body are matched. The shell deformation prevention welding sealing structure is provided to prevent the transmission device shell from being deformed during the welding process.

[0017] Preferably, a housing sealing structure for sealing the transmission device housing toward the vacuum chamber is provided at one end of the transmission device housing toward the vacuum chamber; the housing sealing structure adopts a knife-edge flange or a metal sealing ring. The knife-edge flange or the metal sealing ring is used to achieve sealing with the vacuum chamber, and has good sealing performance, and can be applied to sealing under high vacuum, high pressure difference conditions, and high permeability gas conditions.

[0018] Preferably, the end of the transmission device main shaft away from the vacuum chamber is provided with a main shaft sealing structure for sealing with the transmission shaft; the main shaft sealing structure adopts a knife-edge flange or a metal sealing ring. The knife-edge flange or the metal sealing ring is used to seal with the transmission shaft, and the sealing performance is good, which can be applied to sealing under high vacuum, high pressure difference conditions and high permeability gas conditions.

[0019] The beneficial effects of the present invention are as follows: the magnetic fluid sealing transmission device with high sealing performance has high sealing performance, which can not only meet the use requirements of high vacuum and high pressure difference environment, but also effectively prevent high permeability gas from breaking the vacuum, and can be widely used in environmental conditions with high permeability gas.

[0020] The integrated multi-stage magnetic pole structure is adopted to solve the problem that the current single magnetic pole setting has no seal between the magnetic poles, and the vacuum is easily broken by high pressure or high permeability gas under high pressure and high permeability gas application conditions, and the problem of not being able to meet the high vacuum is solved. An anti-deformation precision welding structure is set between the welding body set on the integrated multi-stage magnetic pole structure and the transmission device housing, which solves the problem that the magnetic pole and the housing are sealed with O-rings in the prior art, and the sealing cannot meet the high vacuum, high pressure difference, and high permeability gas environment. The transmission device housing and the transmission device main shaft are sealed with knife-edge flanges or metal sealing rings, which solves the problem that the magnetic fluid and the vacuum cavity, and the transmission shaft are sealed with O-rings, which cannot meet the sealing problems in high vacuum, high pressure difference, and high permeability gas environments. The magnetic sealing area is set at one end of the vacuum cavity, and the bearing assembly is set at the end away from the vacuum colloid cavity, which solves the problem that the gas generated by the bearing grease enters the vacuum cavity and affects the vacuum degree. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a structural schematic diagram of a magnetic fluid sealing transmission device with high sealing performance of the present invention.

[0022] Figure 2 It is a structural schematic diagram of the integrated multi-level magnetic pole structure in the present invention.

[0023] Figure 3 It is a structural schematic diagram of the main shaft of the transmission device in the present invention.

[0024] Figure 4 It is another structural schematic diagram of the integrated multi-stage magnetic pole structure in the present invention.

[0025] Figure 5 It is another structural schematic diagram of the main shaft of the transmission device in the present invention.

[0026] Figure 6 It is a structural schematic diagram of a magnetic fluid sealing transmission device with high sealing performance in Example 2 of the present invention.

[0027] In the figure: 1. Transmission housing; 2. Transmission device main shaft, 21. Magnetic fluid sealing part, 22. Bearing mounting part, 23. Drive connecting part, 24. Transmission shaft mounting cavity, 25. Main shaft sealing structure; 3. Integrated multi-stage magnetic pole structure, 31. Multi-stage magnetic pole body, 32. Magnetic block slot, 33. Magnetic block, 34. Magnetic shoe, 35. Magnetic fluid; 4. Bearing assembly, 5. Self-sealing structure, 6. Magnetic pole self-sealing structure, 7. Welding sealing structure; 8. Anti-deformation welding sealing structure, 81. welding body, 82. Anti-deformation welding outer groove, 83. Anti-deformation welding inner groove, 84. Anti-deformation welding end groove; 9. Shell anti-deformation welding sealing structure, 11. Magnetic fluid anti-leakage baffle, 12. Shell sealing structure; 10. Vacuum chamber, 20. Transmission axis. DETAILED DESCRIPTION

[0028] The various aspects of the present invention are described in detail below through specific embodiments in conjunction with the accompanying drawings.

[0029] Embodiment 1: exist Figure 1 , Figure 2 , Figure 3 In the embodiment shown, a magnetic fluid sealed transmission device with high sealing performance includes a transmission device housing 1 for connecting to a vacuum chamber 10 and a transmission device main shaft 2 arranged inside the transmission device housing 1, an integrated multi-stage magnetic pole structure 3 is arranged between the transmission device main shaft 2 and the transmission device housing 1, and the integrated multi-stage magnetic pole structure 3 is arranged at one end of the transmission device main shaft 2 facing the vacuum chamber 10, and a self-sealing structure 5 is formed between the integrated multi-stage magnetic pole structure 3 and the transmission device housing 1, thereby forming a magnetic fluid seal that is resistant to high vacuum, high pressure difference, and high permeability gas. The self-sealing structure 5 includes a magnetic pole self-sealing structure 6 and a welding sealing structure 7.

[0030] A bearing assembly 4 is provided in a cantilever structure at one end of the transmission device main shaft 2 away from the vacuum chamber 10. The bearing assembly 4 is not provided on both sides of the magnetic seal area in a supporting beam structure, but is provided on the outside of the integrated multi-stage magnetic pole structure, and is provided on one side and forms a cantilever structure with the integrated multi-stage magnetic pole structure. During the use of the bearing assembly 4, the gas generated by the grease will not break the magnetic fluid seal and enter the vacuum chamber, affecting the vacuum sealing performance. The bearing assembly 4 near the connection of the transmission shaft 20 can play a better supporting role, making the transmission more stable.

[0031] The integrated multi-level magnetic pole structure 3 includes a multi-level magnetic pole body 31 arranged in an integrated structure, and a plurality of N poles and S poles are arranged on the multi-level magnetic pole body 31. The arrangement of the plurality of N poles and S poles can form a multi-level magnetic seal, which has a higher sealing performance. A plurality of magnetic block slots 32 are radially opened from the outside to the inside on the outer wall of the multi-level magnetic pole body between the N poles and the S poles, and a magnetic block 33 is inserted inside the magnetic block slots 32. The inner wall of the multi-level magnetic pole body 31 is an integrated sleeve structure, and the inner wall has no slots, so as to form an integral structure. The magnetic block slots 32 form a blind groove on the side of the multi-level magnetic pole body 31 facing the transmission device main shaft, that is, it does not pass through. The integrated multi-level magnetic pole structure 3 and the transmission device housing 1 form a magnetic pole self-sealing structure between the outer wall of the multi-level magnetic pole body and the inner wall of the transmission device housing to achieve self-sealing. There is no need to use an O-ring for sealing between the multi-stage magnetic pole body 31 and the transmission device housing 1. Since an integrated multi-stage magnetic pole body is used, there is no gap between the magnetic poles, magnetic blocks and magnetic poles, and high-permeability inert gas will not leak through the gap, thereby achieving effective barrier sealing for high-permeability inert gas.

[0032] In this embodiment, the inner wall of the multi-polar magnetic pole body 31 is a smooth inner wall. No magnetic shoes 34 are arranged on the multi-polar magnetic pole body 31, but a plurality of magnetic shoes 34 are arranged on the transmission device main shaft 2. A magnetic fluid 35 is arranged between the magnetic shoes 34 and the inner wall of the multi-polar magnetic pole body 31. The multi-polar magnetic pole body 31, the magnetic block 33, the magnetic fluid 35 and the transmission device main shaft 2 form a closed magnetic line of force under the magnetic action of the magnetic block 33. The magnetic fluid 35 and the magnetic block 33 form dynamic sealing rings under the action of the magnetic field. The transmission device main shaft 2 and the multi-polar magnetic pole body 31 are sealed by the dynamic sealing ring, thereby forming a sealing structure that can seal high vacuum and high pressure difference and can seal high permeability gas.

[0033] In another embodiment, if Figure 4 , Figure 5 As shown, a plurality of magnetic shoes 34 are arranged on the inner wall where the multi-polar magnetic pole body 31 cooperates with the transmission device main shaft 2, and a plurality of magnetic shoes 34 are not arranged on the transmission device main shaft 2. A magnetic fluid 35 is arranged between the magnetic shoes 34 and the outer wall of the transmission device main shaft 5. The multi-polar magnetic pole body 31, the magnetic block 33, the magnetic fluid 34 and the transmission device main shaft 2 form a closed magnetic field line under the magnetic action of the magnetic block 33. The magnetic fluid 35 and the magnetic block 33 form dynamic sealing rings under the action of the magnetic field. The transmission device main shaft 2 and the multi-polar magnetic pole body 31 are sealed by the dynamic sealing ring, thereby forming a sealing structure that can seal high vacuum and high pressure difference and can seal high permeability gas.

[0034] The welding sealing structure 7 is formed by integrally welding the integrated multi-stage magnetic pole structure 3 and the transmission device housing 1 by argon arc welding to form a sealing structure with high sealing performance.

[0035] In order to prevent the integrated multi-stage magnetic pole structure 3 and the transmission device housing 1 from welding deformation during welding and affecting the sealing performance, an anti-deformation welding sealing structure 8 is provided on the integrated multi-stage magnetic pole structure 3. A housing anti-deformation welding sealing structure 9 is provided on the transmission device housing.

[0036] The anti-deformation welding sealing structure 8 is arranged at one end of the multi-polar magnetic pole body 31 facing the vacuum side. The anti-deformation welding sealing structure 8 includes a welding body 81 integrally arranged on the multi-polar magnetic pole body 31, an anti-deformation welding outer groove 82 is arranged between the welding body 81 and the multi-polar magnetic pole body 31, an anti-deformation welding inner groove 83 is arranged on the inner wall of the welding body 81, and an anti-deformation welding end groove 84 is arranged on the end face of the welding body 81. The shell anti-deformation welding sealing structure 9 is arranged on the end face of the transmission device shell 1 corresponding to the anti-deformation welding end groove 84, and the shell anti-deformation welding sealing structure 9 is an anti-deformation welding groove at the end of the shell.

[0037] After the transmission housing 1 and the multi-polar magnetic pole body 31 are assembled, the transmission housing 1 and the multi-polar magnetic pole body 31 are welded together at the end of the welding body and the transmission housing, so as to be directly sealed by the weld. Due to the provision of the anti-deformation welding sealing structure 8 and the housing anti-deformation welding sealing structure 9, no welding deformation will occur between the multi-polar magnetic pole body 31 and the transmission housing 1 during the welding process, thereby realizing the design of direct weld sealing. The provision of the welding sealing structure 7 realizes the integrated structure of the multi-polar magnetic pole body and the transmission housing, and does not require the provision of an O-ring for sealing, which can meet the requirements of high vacuum, high pressure difference, and high permeability inert gas sealing.

[0038] At the same time, in order to avoid the problem of magnetic fluid leakage between the multi-stage magnetic pole body 31 and the transmission device main shaft 2 during high-speed transmission, a magnetic fluid anti-leakage baffle 11 is also provided between the transmission device main shaft 2 and the multi-stage magnetic pole body 31. A labyrinth-type anti-leakage sealing structure is formed between the magnetic fluid anti-leakage baffle 11 and the multi-stage magnetic pole body and the transmission device main shaft.

[0039] A housing sealing structure 12 is provided at one end of the transmission housing 1 facing the vacuum side.

[0040] The housing sealing structure 12 is a housing CF blade flange disposed at one end of the transmission housing facing the vacuum side, and is used to achieve sealing with the vacuum chamber 10. This solves the problem that the traditional O-ring seal cannot achieve high vacuum, high pressure difference sealing, and cannot achieve sealing of high permeability inert gas. The structure of the CF blade flange or the metal sealing ring can meet the requirements of high vacuum, high pressure difference sealing, and can have the performance of sealing high permeability inert gas.

[0041] The transmission device main shaft 2 includes a magnetic fluid sealing portion 21 , a bearing mounting portion 22 and a drive connecting portion 23 which are integrally arranged.

[0042] A transmission shaft installation cavity 24 is arranged inside the transmission device main shaft 2, and no O-ring sealing groove and O-ring sealing are arranged on the inner wall of the transmission shaft installation cavity 24. Instead, a main shaft sealing structure 25 is arranged on the end surface of the driving connection part 23.

[0043] The spindle sealing structure 25 adopts a spindle CF knife-edge flange, or a spindle metal sealing ring. In this embodiment, the spindle sealing structure 25 adopts a spindle CF knife-edge flange.

[0044] When in use, the transmission shaft 20 cooperates with the transmission shaft installation cavity 24 and realizes a sealed connection with the transmission shaft through the main shaft sealing structure 25. Thus, the sealing requirements of high vacuum and high pressure difference can be realized, and the sealing requirements of high permeability inert gas can also be realized.

[0045] The magnetic fluid sealed transmission device with high sealing performance described in the above embodiment is aimed at the inert gas widely used in the semiconductor and integrated circuit process, which has the problems of small molecular weight, good permeability, and great sealing difficulty. The sealing performance of helium in semiconductor equipment has a great influence on the performance of semiconductor integrated circuits. Therefore, the magnetic fluid sealed transmission device with high sealing performance in the above embodiment realizes the effective sealing of high permeability inert gas such as helium.

[0046] At the same time, the integrated multi-stage magnetic pole structure 3 is arranged at one end close to the vacuum side, and the bearing assembly is arranged at one end away from the vacuum side, which effectively solves the problem of bearing grease outgassing affecting the sealing performance.

[0047] The integrated multi-stage magnetic pole structure solves the problem in the prior art that a single magnetic pole is easily broken by high pressure or high permeability gas under high vacuum, high pressure difference and high permeability inert gas application conditions and cannot be sealed; the anti-deformation precision welding structure of the magnetic pole and the shell solves the problem that the O-ring seal between the magnetic pole and the shell cannot achieve sealing under high vacuum and high pressure difference conditions, and cannot achieve effective sealing for high permeability inert gas; the shell and the main shaft are both sealed with metal sealing knife edge flanges, which solves the problem that the O-ring seal between the magnetic fluid and the vacuum cavity and the transmission shaft cannot achieve sealing under high vacuum and high pressure difference conditions, and cannot achieve effective sealing for high permeability inert gas.

[0048] Embodiment 2: exist Figure 6In the embodiment shown, a magnetic fluid sealed transmission device with high sealing performance includes a transmission device housing 1 for connecting to a vacuum chamber 10 and a transmission device main shaft 2 arranged inside the transmission device housing 1, an integrated multi-stage magnetic pole structure 3 is arranged between the transmission device main shaft 2 and the transmission device housing 1, and the integrated multi-stage magnetic pole structure 3 is arranged at one end of the transmission device main shaft 2 facing the vacuum chamber 10, and a self-sealing structure 5 is formed between the integrated multi-stage magnetic pole structure 3 and the transmission device housing 1, thereby forming a magnetic fluid seal that is resistant to high vacuum, high pressure difference, and high permeability gas. The self-sealing structure 5 includes a magnetic pole self-sealing structure 6 and a welding sealing structure 7.

[0049] A bearing assembly 4 is provided in a cantilever structure at one end of the transmission device main shaft 2 away from the vacuum chamber 10. The bearing assembly 4 is not provided on both sides of the magnetic seal area in a supporting beam structure, but is provided on the outside of the integrated multi-stage magnetic pole structure, and is provided on one side and forms a cantilever structure with the integrated multi-stage magnetic pole structure. During the use of the bearing assembly 4, the gas generated by the grease will not break the magnetic fluid seal and enter the vacuum chamber, affecting the vacuum sealing performance. The bearing assembly 4 near the transmission shaft connection can play a better supporting role, making the transmission more stable.

[0050] The integrated multi-level magnetic pole structure 3 includes a multi-level magnetic pole body 31 arranged in an integrated structure, and a plurality of N poles and S poles are arranged on the multi-level magnetic pole body 31. The arrangement of the plurality of N poles and S poles can form a multi-level magnetic seal, which has a higher sealing performance. A plurality of magnetic block slots 32 are radially opened from the outside to the inside on the outer wall of the multi-level magnetic pole body between the N poles and the S poles, and a magnetic block 33 is inserted inside the magnetic block slots 32. The inner wall of the multi-level magnetic pole body 31 is an integrated sleeve structure, and the inner wall has no slots, so as to form an integral structure. The magnetic block slots 32 form a blind groove on the side of the multi-level magnetic pole body 31 facing the transmission device main shaft, that is, it does not pass through. The integrated multi-level magnetic pole structure 3 and the transmission device housing 1 form a magnetic pole self-sealing structure between the outer wall of the multi-level magnetic pole body and the inner wall of the transmission device housing to achieve self-sealing. There is no need to use an O-ring for sealing between the multi-stage magnetic pole body 31 and the transmission device housing 1. Since an integrated multi-stage magnetic pole body is used, there is no gap between the magnetic poles, magnetic blocks and magnetic poles, and high-permeability inert gas will not leak through the gap, thereby achieving effective barrier sealing for high-permeability inert gas.

[0051] In this embodiment, a plurality of magnetic shoes 34 are arranged on the transmission device main shaft 2, and a magnetic fluid 35 is arranged between the magnetic shoes 34 and the inner wall of the multi-polar magnetic body 31. The multi-polar magnetic body 31, the magnetic block 33, the magnetic fluid 34 and the transmission device main shaft 2 form a closed magnetic line of force under the magnetic action of the magnetic block 33. The magnetic fluid 35 and the magnetic block 33 form dynamic sealing rings under the action of the magnetic field. The transmission device main shaft 2 and the multi-polar magnetic body 31 are sealed by the dynamic sealing ring, thereby forming a sealing structure that can seal high vacuum and high pressure difference and can seal high permeability gas.

[0052] In another embodiment, a plurality of magnetic shoes 34 are arranged on the inner wall where the multi-polar magnetic pole body 31 cooperates with the transmission device main shaft 2, and a plurality of magnetic shoes 34 are not arranged on the transmission device main shaft 2. A magnetic fluid 35 is arranged between the magnetic shoes 34 and the outer wall of the transmission device main shaft 5. The multi-polar magnetic pole body 31, the magnetic block 33, the magnetic fluid 34 and the transmission device main shaft 2 form a closed magnetic line of force under the magnetic action of the magnetic block 33. The magnetic fluid 35 and the magnetic block 33 form dynamic sealing rings under the action of the magnetic field. The transmission device main shaft 2 and the multi-polar magnetic pole body 31 are sealed by the dynamic sealing ring, thereby forming a sealing structure that can seal high vacuum and high pressure difference and can seal high permeability gas.

[0053] The welding sealing structure 7 is formed by integrally welding the integrated multi-stage magnetic pole structure 3 and the transmission device housing 1 by argon arc welding to form a sealing structure with high sealing performance.

[0054] In order to prevent the integrated multi-stage magnetic pole structure and the transmission device housing from welding deformation during welding, which affects the sealing performance, an anti-deformation welding sealing structure 8 is provided on the integrated multi-stage magnetic pole structure 3. A housing anti-deformation welding sealing structure 9 is provided on the transmission device housing.

[0055] The anti-deformation welding sealing structure 8 is arranged at one end of the multi-polar magnetic pole body 31 facing the vacuum side. The anti-deformation welding sealing structure 8 includes a welding body 81 integrally arranged on the multi-polar magnetic pole body 31, an anti-deformation welding outer groove 82 is arranged between the welding body 81 and the multi-polar magnetic pole body 31, an anti-deformation welding inner groove 83 is arranged on the inner wall of the welding body 81, and an anti-deformation welding end groove 84 is arranged on the end face of the welding body 81. The shell anti-deformation welding sealing structure 9 is arranged on the end face of the transmission device shell 1 corresponding to the anti-deformation welding end groove 84, and the shell anti-deformation welding sealing structure 9 is an anti-deformation welding groove at the end of the shell.

[0056] After the transmission housing 1 and the multi-polar magnetic pole body 31 are assembled, the transmission housing 1 and the multi-polar magnetic pole body 31 are welded together at the end of the welding body and the transmission housing, so as to be directly sealed by the weld. Due to the provision of the anti-deformation welding sealing structure 8 and the housing anti-deformation welding sealing structure 9, no welding deformation will occur between the multi-polar magnetic pole body 31 and the transmission housing 1 during the welding process, thereby realizing the design of direct weld sealing. The provision of the welding sealing structure 7 realizes the integrated structure of the multi-polar magnetic pole body and the transmission housing, and does not require the provision of an O-ring for sealing, which can meet the requirements of high vacuum, high pressure difference, and high permeability inert gas sealing.

[0057] At the same time, in order to avoid the problem of magnetic fluid leakage between the multi-stage magnetic pole body 31 and the transmission device main shaft 2 during high-speed transmission, a magnetic fluid anti-leakage baffle 11 is also provided between the transmission device main shaft 2 and the multi-stage magnetic pole body 31. A labyrinth-type anti-leakage sealing structure is formed between the magnetic fluid anti-leakage baffle 11 and the multi-stage magnetic pole body and the transmission device main shaft.

[0058] A housing sealing structure 12 is provided at one end of the transmission housing 1 facing the vacuum side.

[0059] The housing sealing structure 12 adopts a housing metal sealing ring structure, which seals the transmission device housing and the vacuum chamber 10 through the metal sealing ring structure, and can also achieve high vacuum, high pressure difference sealing, and can achieve sealing of high permeability inert gas.

[0060] Since metal seals can withstand temperatures above 450 degrees, some metal seals made of special alloys can even work in a high temperature environment of 700 degrees for a long time; they have good high pressure resistance and are suitable for high pressure and temperature environments; metal seals are usually made of corrosion-resistant metal materials, such as stainless steel, copper alloys and nickel alloys, and have strong corrosion resistance; they have high resilience and can recover to their original shape after being compressed, thereby maintaining a good sealing effect; metal seals have good wear resistance and can maintain good working quality under long-term work and high-intensity pressure; and metal seals have a simple structure and are easy to use and maintain, which helps to increase the service life of the seals. Therefore, they can also meet the requirements of high vacuum and high pressure difference sealing, as well as seals for high-permeability inert gases.

[0061] The transmission device main shaft 2 includes a magnetic fluid sealing portion 21 , a bearing mounting portion 22 and a drive connecting portion 23 which are integrally arranged.

[0062] A transmission shaft installation cavity 24 is arranged inside the transmission device main shaft 2, and no O-ring sealing groove and O-ring sealing are arranged on the inner wall of the transmission shaft installation cavity 24. Instead, a main shaft sealing structure 25 is arranged on the end surface of the driving connection part 23.

[0063] In this embodiment, the spindle sealing structure 25 adopts a spindle metal sealing ring.

[0064] When in use, the transmission shaft 20 cooperates with the transmission shaft installation cavity 24 and realizes a sealed connection with the transmission shaft through the main shaft sealing structure 25. Thus, the sealing requirements of high vacuum and high pressure difference can be realized, and the sealing requirements of high permeability inert gas can also be realized.

[0065] The magnetic fluid sealed transmission device with high sealing performance described in the above embodiment is aimed at the inert gas widely used in the semiconductor and integrated circuit process, which has the problems of small molecular weight, good permeability, and great sealing difficulty. The sealing performance of helium in semiconductor equipment has a great influence on the performance of semiconductor integrated circuits. Therefore, the magnetic fluid sealed transmission device with high sealing performance in the above embodiment realizes the effective sealing of high permeability inert gas such as helium.

[0066] At the same time, the integrated multi-stage magnetic pole structure 3 is arranged at one end close to the vacuum side, and the bearing assembly is arranged at one end away from the vacuum side, which effectively solves the problem of bearing grease outgassing affecting the sealing performance.

[0067] The integrated multi-stage magnetic pole structure solves the problem in the prior art that a single magnetic pole is easily broken by high pressure or high permeability gas under high vacuum, high pressure difference and high permeability inert gas application conditions, thereby affecting the sealing performance; the anti-deformation precision welding structure of the magnetic pole and the shell solves the problem that the O-ring seal between the magnetic pole and the shell cannot achieve sealing under high vacuum and high pressure difference conditions, and cannot achieve effective sealing for high permeability inert gas; the shell and the main shaft are both sealed with a metal sealing ring structure, which solves the problem that the O-ring seal between the magnetic fluid and the vacuum cavity and the transmission shaft cannot achieve sealing under high vacuum and high pressure difference conditions, and cannot achieve effective sealing for high permeability inert gas.

[0068] The above specific implementation modes / embodiments are specific implementation modes of the present invention, which are used to illustrate the concept of the present invention, are explanatory and exemplary, and should not be interpreted as limiting the implementation modes of the present invention and the scope of the present invention. In addition to the embodiments described herein, those skilled in the art can also adopt other obvious technical solutions based on the contents disclosed in the claims and the specification of this application, and these technical solutions include any obvious replacement and modification of the embodiments described herein, which are within the protection scope of the present invention.

Claims

1. A magnetic fluid sealing transmission device with high sealing performance, comprising a transmission device housing (1) for connecting to a vacuum chamber and a transmission device main shaft (2) arranged inside the transmission device housing (1), characterized in that: An integrated multi-stage magnetic pole structure (3) is arranged on one end of the transmission device main shaft (2) facing the vacuum chamber, and a bearing assembly (4) is arranged on the end of the transmission device main shaft (2) away from the vacuum chamber, wherein a self-sealing structure is formed between the integrated multi-stage magnetic pole structure (3) and the transmission device housing (1).

2. The magnetic fluid sealing transmission device with high sealing performance according to claim 1 is characterized in that: The integrated multi-stage magnetic pole structure (3) comprises a multi-stage magnetic pole body (31) and a plurality of magnetic blocks (33) arranged in an integrated structure, wherein a plurality of N poles and S poles are arranged on the multi-stage magnetic pole body (31), a magnetic block slot (32) is arranged between the N poles and the S poles, and the magnetic block (33) is inserted into the magnetic block slot (32).

3. The magnetic fluid sealing transmission device with high sealing performance according to claim 2 is characterized in that: A magnetic shoe (34) and a magnetic fluid (35) forming a magnetic fluid sealing structure are arranged between the integrated multi-stage magnetic pole structure (3) and the transmission device main shaft (2).

4. The magnetic fluid sealing transmission device with high sealing performance according to claim 2 is characterized in that: The magnetic block slot (32) is provided on the outer wall of the multi-stage magnetic pole body (31), and the inner wall of the multi-stage magnetic pole body (31) is an integrated sleeve structure.

5. The magnetic fluid sealing transmission device with high sealing performance according to claim 2, characterized in that: A magnetic fluid anti-leakage baffle (11) is provided at one end of the transmission device main shaft (2) facing the vacuum chamber.

6. The magnetic fluid sealing transmission device with high sealing performance according to claim 1 is characterized in that: An anti-deformation welding sealing structure (8) is provided on the integrated multi-stage magnetic pole structure (3), and the anti-deformation welding sealing structure (8) is arranged at one end of the integrated multi-stage magnetic pole structure (3) facing the vacuum side.

7. The magnetic fluid sealing transmission device with high sealing performance according to claim 6 is characterized in that: The anti-deformation welding sealing structure (8) comprises a welding body (81) integrally arranged with the integrated multi-stage magnetic pole structure (3), an anti-deformation welding outer groove (82) is arranged on the outer wall of the welding body (81), an anti-deformation welding inner groove (83) is arranged on the inner wall of the welding body (81), and an anti-deformation welding end groove (84) is arranged on the end surface of the welding body (81).

8. The magnetic fluid sealing transmission device with high sealing performance according to claim 7, characterized in that: A shell deformation prevention welding sealing structure (9) is provided on the end surface of the transmission device shell (1) where it cooperates with the welding body (81).

9. The magnetic fluid sealing transmission device with high sealing performance according to any one of claims 1 to 8, characterized in that: A housing sealing structure (12) for achieving sealing with the vacuum cavity is provided at one end of the transmission device housing (1) facing the vacuum cavity; the housing sealing structure (12) adopts a knife-edge flange or a metal sealing ring.

10. The magnetic fluid sealing transmission device with high sealing performance according to any one of claims 1 to 8, characterized in that: The end of the transmission device main shaft (2) away from the vacuum chamber is provided with a main shaft sealing structure (25) for sealing with the transmission shaft; the main shaft sealing structure (25) adopts a knife-edge flange or a metal sealing ring.

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