Molecular pump

Abstract

The utility model provides a molecular pump. The molecular pump comprises a shell 1, a magnetic bearing center shaft assembly, a main shaft assembly, a traction assembly and a base 20. The magnetic bearing central shaft assembly comprises a magnetic bearing central shaft 2, an adjusting ring 6 and a permanent magnet bearing; the main shaft assembly is assembled on the shell 1 through a magnetic bearing central shaft 2; the traction assembly is connected with the main shaft assembly, and the base 20 is connected with the traction assembly; the permanent magnet bearing is sleeved on the magnetic bearing central shaft 2; wherein the permanent magnet bearing comprises an inner magnetic ring 3 and an outer magnetic ring 4, and the inner magnetic ring 3 is mounted on the magnetic bearing central shaft 2; an adjusting ring 6 is arranged on the end face of the inner magnetic ring 3 away from the spindle; the outer magnetic ring 4 is mounted in a groove in the upper part of a main shaft 5 of the main shaft assembly; the non-contact permanent magnet bearing is used as a constraint support at the high vacuum part of the upper half part of the main shaft assembly, and is free of abrasion and high in reliability; and the axial vibration damping and the radial vibration damping are arranged at the mechanical bearing, so that the operation vibration is effectively reduced, and meanwhile, the assembly accumulated error is made up.

Description

Technical Field

[0001] This utility model belongs to the field of vacuum generation equipment, specifically, it relates to a molecular pump. Background Technology

[0002] Molecular pumps, as mainstream vacuum generating devices, are used in scientific research, new energy, semiconductors, aerospace, and other fields. These applications often place extremely high demands on pumping efficiency, cleanliness, vacuum level, and vibration control. Traditional molecular pumps suffer from a series of problems, including mediocre pumping performance, insufficient rotor rigidity, poor dynamic characteristics, grease volatilization in mechanical bearings, unreliable and short lifespan, and overheating, making them increasingly unable to meet the demands of these industries.

[0003] Chinese patent application CN106015034A discloses a high-pressure ratio composite molecular pump with a pressure ratio on the order of 10. 10 ~10 11 The system includes a turbine section and a traction section. The turbine section consists of a moving impeller and stationary blades to achieve a high pumping speed. The traction section consists of a traction drum and a traction groove to achieve a high pressure ratio. The high pressure ratio composite molecular pump of this invention also adds a disc traction function between the turbine section and the traction section. That is, a traction disc is installed on the moving impeller assembly, and a traction groove disc with arc or straight grooves machined on both sides is installed on the outer groove. The added two-stage traction function can effectively improve the pressure ratio of the molecular pump, reduce the vacuum pressure inside the vacuum chamber, improve the pumping performance of the composite molecular pump, and meet the instrument's requirements for ultra-low vacuum.

[0004] Existing molecular pumps suffer from significant vibration leading to large cumulative assembly errors and poor heat dissipation. Utility Model Content

[0005] In view of the deficiencies in the prior art, the purpose of this utility model is to provide a molecular pump.

[0006] The molecular pump provided by this utility model includes: a housing 1, a magnetic bearing central shaft assembly, a main shaft assembly, a traction assembly, and a base 20;

[0007] The magnetic bearing central shaft assembly includes: a magnetic bearing central shaft 2, an adjusting ring 6, and a permanent magnet bearing;

[0008] The main spindle assembly is mounted on the housing 1 via the magnetic bearing central shaft 2; the traction assembly is connected to the main spindle assembly, and the base 20 is connected to the traction assembly;

[0009] The permanent magnet bearing is sleeved on the central shaft 2 of the magnet bearing;

[0010] The permanent magnet bearing includes an inner magnetic ring 3 and an outer magnetic ring 4.

[0011] The inner magnetic ring 3 is mounted on the central shaft 2 of the magnetic bearing; an adjusting ring 6 is provided on the end face of the inner magnetic ring 3 away from the main shaft;

[0012] The outer magnetic ring 4 is installed in the groove on the upper part of the spindle 5 of the spindle assembly.

[0013] Preferably, the spindle assembly includes: a moving blade 7 and a stationary blade 8;

[0014] The number of the moving blades 7 and the stationary blades 8 is multiple;

[0015] The plurality of moving blades 7 are spaced and sleeved on the main shaft 5;

[0016] The plurality of stationary blades 8 are fixedly mounted on the housing 1;

[0017] Multiple moving blades 7 and multiple stationary blades 8 on the main shaft assembly are staggered in the upper part of the main shaft to form a multi-stage turbine; and the blade angles of the moving blades 7 and the stationary blades 8 are opposite in the circumferential direction.

[0018] Preferably, a radially extending platform is provided in the middle part of the main shaft 5, and the platform is provided with multiple circular grooves near the axis of the main shaft 5; the multiple circular grooves are engaged with the air-blocking structure 9.

[0019] Preferably, the traction assembly includes: a rotor 17, a stator 16, a first carbon fiber tube 10, a second fiber tube 11, a first helical component 12, a second helical component 13, and a third helical component 14, all sleeved on the lower end of the platform of the main shaft 5.

[0020] The stator 16 is connected to the first spiral component 12;

[0021] The main shaft 5 is fitted with a first spiral component 12, a second fiber tube 11, a second spiral component 13, a first carbon fiber tube 10, and a third spiral component 14 in a radial sequence.

[0022] One end of the first spiral component 12 is connected to the air-blocking structure 9, and the other end of the first spiral component 12 is connected to the base 20; the second fiber tube 11 and the first carbon fiber tube 10 are both fixed on the platform set on the main shaft, and there is an air passage between the second spiral component 13 and the platform set on the main shaft for airflow to pass through. The second spiral component 13 is fixedly connected to the base 20; the end of the platform is connected to the first carbon fiber tube 10 on the traction assembly.

[0023] One end of the third spiral component 14 is connected to the lower end of the housing 1, and the other end of the third spiral component 14 is connected to the base 20.

[0024] Preferably, both the first carbon fiber tube 10 and the second fiber tube 11 are smooth annular shapes;

[0025] The first spiral component 12, the second spiral component 13, and the third spiral component 14 are provided with spiral grooves.

[0026] Preferably, the traction assembly further includes: a mechanical bearing 19, a bearing housing 18, an oil-cotton assembly 23, and a sealing plate 24;

[0027] The lower end of the main shaft 5 is fitted with a mechanical bearing 19 and a bearing seat 18 in sequence along the axial direction; the bearing seat 18 is used to support the mechanical bearing 19.

[0028] The oil-cotton assembly 23 is located between the bottom of the mechanical bearing 19 and the base 20, and the sealing plate 24 is located below the oil-cotton assembly 23.

[0029] Preferably, the bearing housing 18 is provided with grooves in both the axial and radial directions;

[0030] The bearing housing 18 is provided with an axial damping 21 and a radial damping 22 in its grooves; wherein the axial damping 21 is provided in the grooves of the mechanical bearing 19 and the bearing housing 18 in the axial direction; and the radial damping 22 is provided in the grooves of the mechanical bearing 19 and the bearing housing 18 in the radial direction.

[0031] Preferably, the base 20 is further provided with a water cooling structure 25 and an air cooling structure 26.

[0032] The water cooling structure 25 is installed in a groove opened circumferentially in the base 20;

[0033] The air-cooled structure 26 is located on the lower end face of the base 20.

[0034] Preferably, a stepped structure is provided at the connection between the main shaft 5 and the plurality of moving blades 7, wherein a portion of the moving blades 7 are located in the upper part of the stepped structure and another portion of the moving blades 7 are located in the lower part of the stepped structure.

[0035] Preferably, it also includes a driver 15, which is mounted outside the housing 1 and electrically connected to the stator 16.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] This utility model features an optimized design for the spindle assembly and spindle itself, resulting in a lightweight, high-strength, one-piece molding process with excellent manufacturability and high precision. The non-contact permanent magnet bearing serves as a constraint support in the high vacuum area of ​​the upper part of the spindle assembly, eliminating wear and ensuring high reliability.

[0038] This invention effectively reduces operating vibration and compensates for accumulated assembly errors by providing axial and radial vibration damping at the mechanical bearing.

[0039] This invention features an air-blocking structure that dynamically isolates the space on the motor side, providing a more efficient and cleaner high-vacuum environment. It also offers both water-cooling and air-cooling structures for effective heat dissipation, extending the lifespan of the bearings and motor, and further enhancing reliability. The oil-cotton assembly at the mechanical bearing is easy to disassemble, facilitating maintenance. Attached Figure Description

[0040] Other features, objects and advantages of the present invention will become more apparent from the detailed description of the non-limiting embodiments with reference to the following drawings:

[0041] Figure 1 This is a schematic diagram of the overall structure of the molecular pump of this utility model;

[0042] Figure 2 This is a schematic diagram of the base and the second spiral component 13 provided by this utility model in cooperation;

[0043] The figure shows

[0044] Housing 1, First carbon fiber cylinder 10, Mechanical bearing 19

[0045] Magnetic bearing central shaft 2, second carbon fiber cylinder 11, base 20

[0046] Inner magnetic ring 3, first helical component 12, axial vibration damping 21

[0047] Outer magnetic ring 4, second helical component 13, radial vibration damping 22

[0048] Main shaft 5, third spiral component 14, oil cotton assembly 23

[0049] Adjusting ring 6, driver 15, sealing plate 24

[0050] 7 moving blades, 16 stators, 25 water-cooled structures

[0051] 8 stationary blades, 17 rotors, 26 air-cooled structure

[0052] Air-blocking structure 9, bearing housing 18 Detailed Implementation

[0053] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the present invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0054] This utility model provides a molecular pump, including a housing 1, a magnetic bearing central shaft assembly, a main shaft assembly, a traction assembly, a base assembly, and a controller;

[0055] The spindle assembly is interference-fitted onto the housing 1 via the magnetic bearing center shaft 2 on the magnetic bearing center shaft assembly; the traction assembly is connected to the spindle assembly, and the base assembly is connected to the traction assembly.

[0056] The magnetic bearing central shaft assembly includes: magnetic bearing central shaft 2, adjusting ring 6, and permanent magnet bearing.

[0057] A permanent magnet bearing is mounted on the central shaft 2 of a magnetic bearing. The permanent magnet bearing includes an inner magnetic ring 3 and an outer magnetic ring 4.

[0058] The number of inner magnetic ring 3 and outer magnetic ring 4 is one or more. The inner magnetic ring 3 is installed on the central shaft 2 of the magnetic bearing. An adjustment ring 6 is provided on the end face of the inner magnetic ring 3 away from the main shaft.

[0059] The outer magnetic ring 4 is interference-fitted into the groove on the upper part of the spindle 5. The outer magnetic ring 4 and the inner magnetic ring 3 do not contact each other. The magnetic force resists uniform constraint and supports the spindle assembly, thereby making the spindle assembly wear-free and highly clean.

[0060] The main spindle assembly includes: main spindle 5, moving blade 7, and stationary blade 8;

[0061] The spindle 5 is made of aerospace aluminum alloy, with small structural inertia and high stability. One end is rotatably connected to the permanent magnet bearing, and the other end is mounted on the mechanical bearing 19.

[0062] The outer magnetic ring 4, main shaft 5, and moving blade 7 are sequentially fitted onto the main shaft assembly with small interference heat sinks from the inside to the outside.

[0063] There are multiple moving blades 7 and multiple stationary blades 8. Multiple moving blades 7 are spaced apart and sleeved on the main shaft 5. Multiple stationary blades 8 are fixedly mounted on the housing 1. Multiple moving blades 7 and multiple stationary blades 8 on the rotor assembly are staggered in the upper part of the main shaft, thus forming a multi-stage turbine. The blade angles of the moving blades 7 and the stationary blades 8 are opposite in the circumferential direction.

[0064] The main shaft is integrally formed 5, and its 6 heat-shrink mating surfaces are machined in one clamping to ensure accuracy; the mating surfaces for installing multiple moving blades 7 are designed with two dimensions to form a stepped structure, which enhances its manufacturability.

[0065] Specifically, a stepped structure is provided at the connection between the main shaft 5 and the multiple moving blades 7, with some of the moving blades 7 located in the upper part of the stepped structure and others located in the lower part of the stepped structure.

[0066] The stationary blade 8 is formed by molding, with a reinforcing groove on the inner side and a edging on the outer side to increase rigidity and for positioning.

[0067] A radially extending platform is provided in the middle part of the main shaft 5, and multiple circular grooves are provided on the platform near the center line of the main shaft 5; the multiple circular grooves are engaged with the air-blocking structure 9.

[0068] During the dynamic operation of the rotor, the motor side is isolated from the high-vacuum side of the air extraction to ensure air extraction efficiency and cleanliness.

[0069] The end of the platform is connected to the first carbon fiber cylinder 10 on the traction assembly;

[0070] The traction assembly includes: a rotor 17 and a stator 16 mounted on the lower end of the platform of the main shaft 5;

[0071] Stator 16 is connected to the first spiral component 12;

[0072] A first spiral component 12, a second fiber tube 11, a second spiral component 13, a first carbon fiber tube 10, and a third spiral component 14 are sequentially arranged radially from the main shaft 5; by arranging them in sequence, a three-stage compression traction stage is formed;

[0073] Both the first carbon fiber tube 10 and the second fiber tube 11 are smooth circular rings; the first carbon fiber tube 10 and the second fiber tube 11 are sequentially fitted onto the traction assembly with small interference heat packs from the inside to the outside.

[0074] The first spiral component 12, the second spiral component 13, and the third spiral component 14 are provided with spiral grooves that run along the air passage. This traction stage has a long air passage and a significant compression effect.

[0075] Furthermore, one end of the first spiral component 12 is connected to the air-blocking structure 9, and the other end is connected to the base 20 on the base assembly; the second fiber tube 11 and the first carbon fiber tube 10 are both fixed on the platform of the main shaft, and there is an air passage between the second spiral component 13 and the platform on the main shaft for airflow to pass through; the second spiral component 13 is fixedly connected to the base 20.

[0076] One end of the third spiral component 14 is connected to the lower end of the housing 1, and the other end is connected to the base 20 on the base assembly;

[0077] The driver 15 is fixed to the outside of the pump and is sealed to ensure that the motor is driven under vacuum. The driver 15 controls the motor stator 16 to magnetically pull the motor rotor 17 to rotate at high speed. The driver 15 is installed outside the housing 1 and is electrically connected to the stator 16.

[0078] Stator 16 is an ultra-high speed brushless permanent magnet motor; rotor 17 is a permanent magnet.

[0079] The lower end of the main shaft 5 is fitted with a mechanical bearing 19 and a bearing housing 18 in sequence along the axial direction; the bearing housing 18 is used to support the mechanical bearing 19.

[0080] Furthermore, the bearing housing 18 is provided with axial damping 21 and radial damping 22, which can effectively reduce operating vibration and compensate for accumulated assembly errors.

[0081] An axial damping damper 21 and a radial damping damper 22 are respectively provided in the grooves of the bearing housing 18; wherein the axial damping damper 21 is provided in the grooves of the mechanical bearing 19 and the bearing housing 18 in the axial direction; and the radial damping damper 22 is provided in the grooves of the mechanical bearing 19 and the bearing housing 18 in the radial direction.

[0082] The base assembly is also equipped with an oil-cotton component 23 and a sealing plate 24;

[0083] The oil-cotton assembly 23 is composed of multiple layers of stacked oil-cotton and is located between the bottom of the mechanical bearing 19 and the base 20. It can store a certain amount of lubricating oil for daily use during bearing operation. The oil-cotton assembly 23 is easy to disassemble and convenient for maintenance. The sealing plate 24 is used for sealing and is located below the oil-cotton assembly 23.

[0084] The base 20 is equipped with a water cooling structure 25 and an air cooling structure 26, which can effectively dissipate heat and improve lifespan and reliability. The water cooling structure 25 is located in a groove opened in the circumferential direction of the base 20, and the air cooling structure 26 is located on the lower end face of the base 20.

[0085] After the base 20 and the second spiral component 13 are processed, they are press-fitted together, which reduces the difficulty of the process while ensuring accuracy. A rectangular groove is provided on the outer cylindrical surface of the base to increase the air cooling effect. The rectangular groove is formed in one step by a saw blade milling cutter.

[0086] Working principle:

[0087] The molecular pump operates as follows: it is supported by a non-contact permanent magnet bearing composed of an inner magnetic ring 3 and an outer magnetic ring 4, and a mechanical bearing; a turbine stage is formed by moving blades 7 and stationary blades 8; a traction stage is formed by a first helical component 12, a second fiber tube 11, a second helical component 13, a first carbon fiber tube 10, and a third helical component 14; the driver drives the stator of the motor to magnetically traction the rotor assembly to rotate at high speed; under the high-speed rotation of the rotor assembly, gas molecules enter from the inlet, and enter the traction stage through the directional impact motion of the moving and stationary blades in the turbine stage. In the traction stage, they are tractioned by the high-speed rotating carbon fiber tube and the directional helical groove, and finally discharged from the exhaust port after three stages of compression. During the process, the rotor assembly, as a moving part, has strong operational stability and high reliability through structural and process optimization; at the same time, during the pumping process, the gas blocking mechanism 9 dynamically isolates the motor side to prevent oil and gas from the mechanical bearing from entering the high vacuum side and causing contamination. The permanent magnet bearings are contactless and lossless, while the mechanical bearings have axial and radial damping to ensure stable operation. The water-cooling and air-cooling structures ensure good heat dissipation for the bearings and motor, further extending service life and reliability.

[0088] The molecular pump provided by this utility model features a main shaft assembly and an optimized main shaft design that is lightweight, high-strength, integrally formed, highly manufacturable, and highly precise. A non-contact permanent magnet bearing serves as a constraint support in the high-vacuum area of ​​the upper part of the rotor assembly, eliminating wear and ensuring high reliability. The mechanical bearing incorporates axial and radial vibration damping to effectively reduce operating vibration and compensate for accumulated assembly errors. An air-blocking structure dynamically isolates the space on the motor side, providing a more efficient and cleaner high-vacuum environment. Water and air cooling structures are provided for effective heat dissipation, extending the lifespan of the bearings and motor, and further enhancing reliability. The oil-soaked cotton assembly at the mechanical bearing is easy to disassemble and convenient for maintenance.

[0089] In the description of this application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0090] The specific embodiments of this utility model have been described above. It should be understood that this utility model is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the substantive content of this utility model. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. A molecular pump, characterized in that, include: Includes housing (1), magnetic bearing central shaft assembly, main shaft assembly, traction assembly, and base (20); The magnetic bearing central shaft assembly includes: a magnetic bearing central shaft (2), an adjusting ring (6), and a permanent magnet bearing; The main spindle assembly is mounted on the housing (1) via the magnetic bearing central shaft (2); the traction assembly is connected to the main spindle assembly, and the base (20) is connected to the traction assembly; The permanent magnet bearing is sleeved on the central shaft (2) of the magnet bearing; The permanent magnet bearing includes an inner magnetic ring (3) and an outer magnetic ring (4). The inner magnetic ring (3) is mounted on the central shaft (2) of the magnetic bearing; an adjusting ring (6) is provided on the end face of the inner magnetic ring (3) away from the main shaft; The outer magnetic ring (4) is installed in the groove on the upper part of the spindle (5) of the spindle assembly.

2. The molecular pump according to claim 1, characterized in that, The main shaft assembly includes: a moving blade (7) and a stationary blade (8); The number of the moving blades (7) and the stationary blades (8) is multiple; The plurality of moving blades (7) are spaced apart and sleeved on the main shaft (5); The plurality of stationary blades (8) are fixedly mounted on the housing (1); Multiple moving blades (7) and multiple stationary blades (8) on the main shaft assembly are staggered on the upper part of the main shaft to form a multi-stage turbine; and the blade angles of the moving blades (7) and the stationary blades (8) are opposite in the circumferential direction.

3. The molecular pump according to claim 1, characterized in that, A radially extending platform is provided in the middle part of the main shaft (5), and the platform is provided with multiple circular grooves near the axis of the main shaft (5); the multiple circular grooves are engaged with the air-blocking structure (9).

4. The molecular pump according to claim 3, characterized in that, The traction assembly includes: a rotor (17) sleeved on the lower end of the platform of the main shaft (5), a stator (16), a first carbon fiber tube (10), a second fiber tube (11), a first spiral component (12), a second spiral component (13), and a third spiral component (14); The stator (16) is connected to the first spiral component (12); The main shaft (5) is fitted with a first spiral component (12), a second fiber tube (11), a second spiral component (13), a first carbon fiber tube (10), and a third spiral component (14) in a radial sequence; One end of the first spiral component (12) is connected to the air-blocking structure (9), and the other end of the first spiral component (12) is connected to the base (20); the second fiber tube (11) and the first carbon fiber tube (10) are both fixed on the platform set on the main shaft, and there is an air passage between the second spiral component (13) and the platform set on the main shaft for airflow to pass through. The second spiral component (13) is fixedly connected to the base (20); the end of the platform is connected to the first carbon fiber tube (10) on the traction assembly. One end of the third spiral member (14) is connected to the lower end of the housing (1), and the other end of the third spiral member (14) is connected to the base (20).

5. The molecular pump according to claim 4, characterized in that, Both the first carbon fiber tube (10) and the second fiber tube (11) are smooth circular rings; The first spiral component (12), the second spiral component (13), and the third spiral component (14) are provided with spiral grooves.

6. The molecular pump according to claim 1, characterized in that, The traction assembly also includes: a mechanical bearing (19), a bearing housing (18), an oil-cotton assembly (23), and a sealing plate (24); The lower end of the main shaft (5) is fitted with a mechanical bearing (19) and a bearing seat (18) in sequence along the axial direction; the bearing seat (18) is used to support the mechanical bearing (19); The oil-cotton assembly (23) is located between the bottom of the mechanical bearing (19) and the base (20), and the sealing plate (24) is located below the oil-cotton assembly (23).

7. The molecular pump according to claim 6, characterized in that, The bearing housing (18) is provided with grooves in both the axial and radial directions; The bearing housing (18) is provided with an axial damping (21) and a radial damping (22) in the grooves respectively; wherein the axial damping (21) is provided in the grooves of the mechanical bearing (19) and the bearing housing (18) in the axial direction; and the radial damping (22) is provided in the grooves of the mechanical bearing (19) and the bearing housing (18) in the radial direction.

8. The molecular pump according to claim 1, characterized in that, The base (20) is also provided with a water cooling structure (25) and an air cooling structure (26). The water cooling structure (25) is installed in a groove opened circumferentially in the base (20); The air-cooled structure (26) is located on the lower end face of the base (20).

9. The molecular pump according to claim 2, characterized in that, The connection between the main shaft (5) and the multiple moving blades (7) is provided with a stepped structure, in which a portion of the moving blades (7) are located on the upper part of the stepped structure and another portion of the moving blades (7) are located on the lower part of the stepped structure.

10. The molecular pump according to claim 1, characterized in that, It also includes a driver (15) which is mounted outside the housing (1) and electrically connected to the stator (16).

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