CN215256873U - Turbo molecular pump - Google Patents

Abstract

The utility model discloses a turbo molecular pump belongs to molecular pump technical field. The utility model discloses a turbo molecular pump, which comprises a pump shell, at least four wheel hubs, at least four stages of impeller sets and a driving piece, wherein the at least four wheel hubs are rotatably arranged in the pump shell; the impeller set comprises movable impellers and fixed impellers, the movable impellers of at least four stages of impeller sets are correspondingly arranged on at least four hubs one by one, and the movable impellers and the fixed impellers are alternately arranged along the airflow direction; the movable impeller comprises a plurality of movable blades, the movable blades are airfoil-shaped blades, and the ratio of the outer diameter of the hub to the outer diameter of the corresponding movable impeller ranges from 0.4 to 0.7; the compression ratio range of the single-stage impeller set is 1.4-2; the driving piece is used for driving the hub to rotate. The moving blade width is great, and the single-stage compression ratio is higher, satisfies under the same vacuum requirement, can reduce the blade quantity of turbine molecular pump's every grade moving impeller for the moving impeller structure is simpler easily to be made, has still reduced the influence to the operating mode point is nonuniform.

Description

Turbo molecular pump

Technical Field

The utility model relates to a molecular pump technical field especially relates to a turbo molecular pump.

Background

The turbo-molecular pump is a vacuum pump which transfers momentum to gas molecules by using a moving impeller rotating at a high speed to make the gas generate directional flow and extract air. The turbo molecular pump has the characteristics of high pumping speed, quick start, no oil pollution, simple maintenance and the like, and is widely applied to the fields of aerospace aviation, medical equipment, instruments and meters and the like.

The turbo molecular pump belongs to the field of kinetic energy vacuum pumps. The turbomolecular pump mainly comprises a pump body, a rotor (movable impeller) with blades, a stationary impeller, a driving system and the like. The linear velocity of the outer edge of the movable impeller is as high as the velocity of the gas molecule thermal motion (generally 150-. The compression ratio of a single-stage impeller (consisting of a single-stage stationary impeller and a single-stage movable impeller) is small, and the turbomolecular pump consists of more than five stages of impellers. The movable impellers and the stationary impellers are alternately arranged. And a stationary impeller is arranged between every two movable impellers. In the turbomolecular pump in the prior art, the geometric dimensions of the moving impeller and the static impeller are basically the same, but the blade inclination angles are opposite. The outer edges of the stationary blades are fixed by a ring, and the distance between the stationary blades is maintained at about 1mm, so that the movable blades can freely rotate between the stationary blades.

The existing turbo molecular pump mostly adopts an axial flow compressor impeller, the width of the blade of the impeller is narrow, at least five stages of impellers are required to be arranged under the condition of meeting the requirement of the same vacuum degree, the number of the impellers is large, the number of the blades of each stage of impeller is also large, the working condition point is influenced more easily, and the manufacturing cost of the turbo molecular pump is also high.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a turbo molecular pump has improved the single-stage compression ratio to under the prerequisite that does not reduce turbo molecular pump compression ratio, reduce the blade quantity of impeller quantity and every level impeller, can not only reduce turbo molecular pump's cost, can also reduce the influence that is nonuniform to operating mode point.

In order to realize the purpose, the following technical scheme is provided:

a turbomolecular pump comprising:

a pump housing;

at least four wheel hubs rotatably disposed within said pump housing;

the impeller set comprises movable impellers and static impellers, the movable impellers of the impeller set of at least four stages are correspondingly arranged on at least four wheel hubs one by one, the static impellers are fixedly arranged in the pump shell and are alternately arranged along the airflow direction; the movable impeller comprises a plurality of movable blades, each movable blade is an airfoil-shaped blade, and the ratio of the outer diameter of the hub to the outer diameter of the corresponding movable impeller ranges from 0.4 to 0.7; the compression ratio of the single-stage impeller set ranges from 1.4 to 2;

and the driving piece is used for driving at least four hubs to synchronously rotate.

According to the technical scheme, the ratio of the outer diameter of the hub to the outer diameter of the corresponding movable impeller (hereinafter referred to as hub ratio) and the compression ratio of the single-stage impeller are controlled within a certain range, so that under the condition that other conditions are consistent, the movable blade is wider compared with the existing movable blade, the contact time between gas molecules and the movable blade is longer, the movable blade applies more work to the gas molecules, and the gas pressure is higher. The number of blades of each stage of movable impeller of the turbomolecular pump can be reduced under the condition of meeting the requirement of the same vacuum degree, so that the movable impeller is simpler in structure and easy to manufacture, the number of impellers of the turbomolecular pump can be reduced under the condition of meeting the requirement of the same vacuum degree, and the influence on the operating points which are not uniform is reduced. In addition, the moving blades adopt airfoil-shaped blades, the airfoil-shaped blades are beneficial to improving the lift coefficient of the blade profile, so that the resistance coefficient of the blade profile is reduced, the lift coefficient is increased, the airflow attack angle is reduced, the airflow compliance is improved, the flow efficiency is improved, and the gas compression efficiency is further improved.

As an alternative to the turbomolecular pump, the distances between the stationary blades and the moving blades in the same impeller set are sequentially increased from the blade roots of the moving blades toward the blade tips.

The distance between the static impeller and the movable impeller is sequentially increased from the blade root of the movable blade to the blade top, so that the static blade has a back inclination angle along the airflow direction after being installed, gas molecules from the blade root of the movable blade to the blade top are in different contact time with the static impeller, the static impeller is prevented from generating resonance, and the noise generated by the turbo-molecular pump is reduced.

As an alternative to the turbomolecular pump, at least four of the hubs are provided on the same shaft, which is connected to the drive element.

All levels of movable impellers and hubs are arranged on the same rotating shaft and are uniformly controlled by the driving piece, so that the coaxial rotation precision of all levels of movable impellers is ensured while the synchronous operation of all levels of movable impellers and the driving piece is ensured.

As an alternative to the turbomolecular pump, the turbomolecular pump further comprises a fairing arranged at the gas flow inlet of the pump housing.

The airflow before entering the pump shell is columnar, and the airflow after entering the pump shell needs to be converted into annular, so that the airflow entering the pump shell is guided by the fairing, the airflow direction can be gently changed, the energy loss of the airflow is reduced, the movable vane wheel can be reduced to apply work to the air to change the airflow direction, the internal loss of the turbomolecular pump is reduced, and the compression ratio of the turbomolecular pump is improved.

As an alternative to the turbomolecular pump, the turbomolecular pump further comprises a diffuser disposed at an air flow outlet of the pump housing.

The diffuser plays a role in reducing the speed and increasing the pressure of the compressed gas, the flow speed of the gas is reduced, the kinetic energy is reduced, the potential energy is increased, and the compression ratio of the turbo-molecular pump can be further improved. In addition, since the greater the velocity, the greater the energy loss, the reduced flow rate of the gas may also reduce the energy loss of the gas in order to maintain the gas pressure.

As an alternative to turbomolecular pumps, the compression ratio of the impeller assembly in a single stage is in the range of 1.4 to 1.6.

When the compression ratio of the single-stage impeller set is in the range of 1.4-1.6, the requirement on the structural strength of the blades is low, and the design and the manufacture are easier.

As an alternative to the turbomolecular pump, the stationary vane wheel comprises a plurality of stationary vanes, which are of a cambered plate-shaped structure.

The fixed blades are arranged into cambered surface plate-shaped structures, so that airflow can be straightened, and the airflow direction is not changed while compression is carried out.

As an alternative of the turbomolecular pump, a connecting structure is arranged on the moving blade, and the connecting structure is fixedly connected with the corresponding hub.

The movable blade and the hub are integrally assembled by the connecting structure, and compared with the structure in which the hub and the movable blade are integrally formed, the movable blade is convenient to process and assemble.

As an alternative to the turbomolecular pump, the installation angles of the moving blades of the at least four stages of the impeller sets are the same in the direction of gas flow, and the outer diameters of the moving blades of the at least four stages of the impeller sets are gradually reduced.

Along the direction of gas flow, the gas flows through at least four stages of impeller groups, the volume of the gas is gradually reduced, the vacuum degree is gradually reduced, the working condition of the gas entering the next stage of impeller set is different from that entering the previous stage, in order to ensure the working efficiency of each stage of impeller set, the outer diameters of the movable impellers of at least four stages of impeller groups are sequentially reduced along the airflow direction on the premise of ensuring the same installation angle of the movable blades of all stages of movable impellers so as to increase the hub ratio and reduce the flow area, thereby reducing the gas flow passing through the impeller set, achieving the purpose of reducing the rated working capacity of each stage of impeller set step by step, matching the rated working capacity of each stage of impeller set with the volume flow of the gas contacting with the impeller set, avoiding the independent surge of a certain stage of impeller set, therefore, the purpose of unifying the surge points of impellers at all levels can be realized, and the stability of the operation of the turbomolecular pump is ensured.

As an alternative of the turbomolecular pump, in the direction of the gas flow, the installation angle of the moving blades of the at least four stages of the blade wheel sets is gradually decreased, the inner diameters of the moving blades of the at least four stages of the blade wheel sets are the same or gradually increased, and the outer diameters of the moving blades are the same.

Along the direction of airflow, the gas flows through at least four stages of impeller sets, the volume of the gas is gradually reduced, the vacuum degree is gradually reduced, the working condition of the gas entering the next stage of impeller set is different from the working condition of the gas entering the previous stage, in order to ensure the working efficiency of each stage of impeller set, under the premise that the outer diameter of the movable impeller is unchanged and the inner diameter of the movable impeller is not gradually reduced along the direction of airflow, the installation angle of the movable blade of the movable impeller is set to be gradually reduced along the direction of airflow, so that the attack angle of the airflow is increased, the energy loss during the turning of the airflow is further increased, the effective work done by the movable blade on the airflow is reduced, which is equivalent to the reduction of the working capacity of the movable blade on the airflow, the purpose of gradually reducing the rated working capacity of each stage of impeller set is achieved, the rated working capacity of each stage of impeller set is matched with the volume flow of the gas contacting with the impeller set, and surge of a certain stage of impeller set can be avoided independently, further, the purpose of unifying the surge points of impellers at all levels is realized, and the stability of the operation of the turbomolecular pump is ensured.

Drawings

FIG. 1 is a schematic structural diagram of a turbomolecular pump in an embodiment of the present application;

FIG. 2 is a schematic view of a stator blade from one perspective in an embodiment of the present application;

FIG. 3 is a schematic view of a stator blade from another perspective in an embodiment of the present application;

FIG. 4 is a schematic structural view of a rotor blade from a perspective in an embodiment of the present application;

FIG. 5 is a schematic structural view of a rotor blade from another perspective in an embodiment of the present application.

Reference numerals:

1. a pump housing;

2. a hub;

3. a drive member;

4. an impeller assembly; 41. a movable impeller; 411. moving blades; 4111. a connecting structure; 42. a stationary impeller; 421. a stationary blade;

5. a cowling;

6. a diffuser.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some, but not all, embodiments of the present application. The components of embodiments of the present application, generally described and illustrated in the figures herein, can be arranged and designed in a wide variety of different configurations.

Thus, the following detailed description of the embodiments of the present application, as presented in the figures, is not intended to limit the scope of the claimed embodiments of the present application, but is merely representative of selected embodiments of the present application. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments in the present application without any creative effort belong to the protection scope of the embodiments in the present application.

It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures.

In the description of the embodiments of the present application, it should be noted that the terms "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings or orientations or positional relationships that the products of the present application are usually placed in when used, and are only used for convenience of describing the embodiments of the present application and simplifying the description, but do not indicate or imply that the devices or elements referred to must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the embodiments of the present application. Furthermore, the terms "first," "second," "third," and the like are used solely to distinguish one from another and are not to be construed as indicating or implying relative importance. In the description of the embodiments of the present application, "a plurality" means two or more unless otherwise specified.

In the description of the embodiments of the present application, it should also be noted that, unless otherwise explicitly stated or limited, the terms "disposed" and "connected" are to be interpreted broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; either mechanically or electrically. The specific meanings of the above terms in the embodiments of the present application can be understood in specific cases by those of ordinary skill in the art.

In the embodiments of the present application, unless otherwise explicitly specified or limited, the "over" or "under" of a first feature may include the first and second features being in direct contact, and may also include the first and second features not being in direct contact but being in contact with each other through another feature therebetween. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly under and obliquely below the second feature, or simply meaning that the first feature is at a lesser elevation than the second feature.

Reference will now be made in detail to embodiments of the present application, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are exemplary only for the purpose of explaining embodiments of the present application and are not to be construed as limiting the embodiments of the present application.

As shown in fig. 1-5, the present embodiment provides a turbomolecular pump, which includes a pump housing 1, at least four hubs 2, a driving member 3, and at least four stages of impeller assemblies 4, where the at least four hubs 2 are rotatably disposed in the pump housing 1 and are disposed on a same rotating shaft; the driving piece 3 is connected with the rotating shaft and is used for driving the rotating shaft to rotate; the impeller set 4 comprises movable impellers 41 and static impellers 42, the movable impellers 41 of at least four stages of the impeller sets 4 are correspondingly arranged on at least four hubs 2 one by one, the static impellers 42 are fixedly arranged on the pump shell 1, and the movable impellers 41 and the static impellers 42 are alternately arranged along the airflow direction; the movable vane 41 includes a plurality of movable vanes 411, the movable vanes 411 are airfoil-shaped vanes, and the ratio of the outer diameter of the hub 2 to the outer diameter of the corresponding movable vane 41 is in the range of 0.4 to 0.7; the compression ratio of the single-stage impeller assembly 4 ranges from 1.4 to 2. Preferably, the compression ratio of the single-stage impeller set 4 is in the range of 1.4-1.6, so as to reduce the requirement on the structural strength of the blades and facilitate the design and manufacture. The compression ratio of the single stage impeller train 4 may be any of 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.

The moving blade 411 adopts an airfoil-shaped blade, which is beneficial to improving the lift coefficient of the moving blade 411, so that the resistance coefficient of the moving blade 411 is reduced, the lift coefficient is increased, the airflow attack angle is reduced, the airflow compliance is improved, the flow efficiency is improved, and the gas compression efficiency is improved.

According to the technical scheme, the ratio of the outer diameter of the hub 2 to the outer diameter of the corresponding movable impeller 41 (hereinafter referred to as a hub ratio) and the compression ratio of the single-stage impeller are controlled within a certain range, so that under the condition that other conditions are consistent, the movable blade 411 is wider compared with the existing movable blade, the contact time between gas molecules and the movable blade 411 is longer, the movable blade 411 applies more work to the gas molecules, and the gas pressure is higher. The number of the blades of each stage of the movable impeller 41 of the turbomolecular pump can be reduced under the condition of meeting the requirement of the same vacuum degree, so that the movable impeller 41 is simpler in structure and easy to manufacture, the number of impellers of the turbomolecular pump can be reduced under the condition of meeting the requirement of the same vacuum degree, and the influence on non-uniformity of working points is reduced.

Further, the turbomolecular pump of this embodiment adopts the moving blade 411 of the fan blade structure, and the width of the blade is large, so that the compression ratio of the single-stage impeller set 4 can be as high as 2, which is far higher than the compression ratio of the existing turbomolecular pump.

It should be noted that the turbomolecular pump provided in this embodiment uses a single motor as the driving member 3, which reduces the use requirement for the intermediate shaft and the coupling. The movable impellers 41 and the hubs 2 are arranged on the same rotating shaft and are uniformly controlled by the driving part 3, so that the coaxial rotation precision of the movable impellers 41 is ensured while the movable impellers 41 and the motor synchronously rotate.

Optionally, the turbomolecular pump further comprises a fairing 5, the fairing 5 being arranged at the gas flow inlet of the pump housing 1. Because the airflow before entering the pump shell 1 is columnar, and the airflow after entering the pump shell 1 needs to be converted into annular, the airflow entering the pump shell 1 is guided by the fairing 5, the airflow direction can be gently changed, so that the energy loss of the airflow is reduced, the action of the movable impeller 41 on the air can be reduced to change the airflow direction, namely, the internal loss of the turbomolecular pump is reduced, and the compression ratio of the turbomolecular pump is improved.

Optionally, the turbomolecular pump further comprises a diffuser 6, and the diffuser 6 is disposed at the airflow outlet of the pump housing 1. The diffuser 6 plays a role in reducing the speed and increasing the pressure of the compressed gas, the flow speed of the gas is reduced, the kinetic energy is reduced, the potential energy is increased, and the compression ratio of the turbo-molecular pump can be further improved. In addition, since the greater the velocity, the greater the energy loss, the reduced flow rate of the gas may also reduce the energy loss of the gas in order to maintain the gas pressure.

Alternatively, the installation angles of the moving blades 411 of the moving blades 41 of at least four stages of the impeller sets 4 are the same in the airflow direction, and the outer diameters of the moving blades 41 of at least four stages of the impeller sets 4 are sequentially reduced. It will be appreciated that the mounting angle of the rotor blade 411 is the angle between the chord line of the rotor blade 411 and the plane of rotation of the rotor blade 411. In the same impeller set 4, the inner diameters of the movable impeller 41 and the stationary impeller 42 are equal. In the present embodiment, the number of the impeller sets 4 is five, and the five-stage impeller sets 4 are coaxially connected in series to form a five-stage axial flow turbomolecular pump. In the prior art, for convenience of description, two adjacent impeller sets are taken as an example, the two adjacent impeller sets are respectively referred to as an upper impeller set and a lower impeller set along the airflow direction, after the airflow is compressed by the upper impeller set, the density of the airflow entering the lower impeller set is higher than that of the airflow entering the upper impeller set, the inlet volume flow of the lower impeller set is smaller than that of the upper impeller set, and under the same condition of the two adjacent impeller sets (including the same blade installation angle), the working condition point of the lower impeller set is moved towards the small flow direction compared with the upper impeller set, the pressure coefficient of the lower impeller is increased, the surge point distance from the performance curve of the vacuum pump is reduced, namely, the surge point of the two impeller sets is advanced compared with that of the single impeller set. In this embodiment, along the airflow direction, the gas flows through at least four stages of impeller sets 4, the volume of the gas is gradually reduced, the vacuum degree is gradually reduced, the working condition of the gas when entering the next stage of impeller set 4 is different from the working condition when entering the previous stage, in order to ensure the working efficiency of each stage of impeller set 4, on the premise of ensuring that the installation angles of the moving blades 411 of each stage of moving blades 41 are the same, the outer diameters of the moving blades 41 of at least four stages of impeller sets 4 are sequentially reduced along the airflow direction, so as to increase the hub ratio, reduce the flow area, further reduce the gas flow rate that can pass through the impeller sets 4, achieve the purpose of reducing the rated working capacity of each stage of impeller sets 4 step by step, match the rated working capacity of each stage of impeller set 4 with the volume flow rate of the gas contacting with the impeller set, avoid surge of a certain stage of impeller set 4 from occurring independently, further achieve the purpose of unifying the surge points of each stage of impeller to make each stage of working condition point fall on the same point of the performance curve, the stability of the operation of the turbo vacuum pump is ensured.

In other embodiments, in the airflow direction, the installation angles of the moving blades 411 of the moving blades 41 of at least four stages of the impeller sets 4 decrease step by step and the inner diameters of the moving blades 41 of at least four stages of the impeller sets 4 are the same or increase step by step, and the outer diameters of the moving blades 41 are the same. Along the direction of the air flow, the air flows through at least four stages of impeller 4 sets, the volume of the air is gradually reduced, the vacuum degree is gradually reduced, the working condition of the air entering the next stage of impeller set 4 is different from the working condition of the air entering the previous stage, in order to ensure the working efficiency of each stage of impeller set 4, under the premise that the outer diameter of the movable impeller 41 is unchanged and the inner diameter of the movable impeller 41 is not gradually reduced along the direction of the air flow, the installation angle of the movable blade 411 of the movable impeller 41 is set to be gradually reduced along the direction of the air flow, the angle of attack of the air flow is increased, the energy loss during the turning of the air flow is further increased, the effective work done by the movable blade 411 to the air flow is reduced, which is equivalent to the reduction of the working capacity of the movable blade 411 to the air flow, the purpose of gradually reducing the rated working capacity of each stage of impeller set 4 is achieved, the rated working capacity of each stage of impeller set 4 is matched with the volume flow of the air contacting with the movable blade, and surge of a certain stage of impeller set 4 alone can be avoided, further, the purpose of unifying the surge points of impellers at all levels is realized, and the stability of the operation of the turbomolecular pump is ensured.

Alternatively, the stationary vane 42 includes a plurality of stationary vanes 421, and the plurality of stationary vanes 421 are fixed to the pump housing 1 at equal intervals. Correspondingly, the plurality of rotor blades 411 are fixed to the corresponding hub 2 at equal intervals around the axis of the hub 2 so that the rotor 41 can generate a stable pressure.

Alternatively, as shown in FIGS. 2-3, the stationary blades 421 are cambered plate-shaped structures. The stationary blades 421 are formed in a cambered plate-shaped structure to straighten the air flow without changing the direction of the air flow while performing compression.

Alternatively, as shown in fig. 1, the distances a between the stationary blades 42 and the movable blades 41 in the same impeller set 4 increase in sequence from the root of the movable blade 411 to the tip. The distances between the stationary vane 42 and the movable vane 41 are sequentially increased from the root of the moving blade 411 to the tip, and the stationary vane 421 is installed to have a back rake angle in the airflow direction, so that the contact time of the gas molecules from the root of the moving blade 411 to the tip is different from that of the stationary vane 42, thereby preventing the stationary vane 42 from resonating and reducing the noise generated by the turbo-molecular pump. For easy understanding, the following further explains the spacing between the stationary impeller 42 and the movable impeller 41 in the same impeller assembly 4, and a plane parallel to the axis of the rotating shaft is taken as a section plane to obtain a schematic sectional view of the impeller assembly 4, wherein the minimum distance between the section of the stationary impeller 42 and the section of the movable impeller 41 is the spacing a between the stationary impeller 42 and the movable impeller 41; when a plurality of the above-described cutting planes are provided at intervals in the same radial direction of the rotating shaft (a plane parallel to the axis of the rotating shaft is used as the cutting plane), the minimum distance between the cross section of the stator vane 42 and the cross section of the rotor vane 41 in the plurality of cutting planes increases in order from the root end of the rotor blade 411 to the tip end, that is, the pitch a between the stator vane 42 and the rotor vane 41 increases in order.

Alternatively, as shown in fig. 4 to 5, the rotor blade 411 is provided with a connecting structure 4111, and the connecting structure 4111 is fixedly connected with the hub 2. The rotor blade 411 is integrally assembled with the hub 2 by using the connecting structure 4111, which facilitates the processing and assembly of the rotor blade 411 compared to a structure in which the hub 2 and the rotor blade 411 are integrally formed.

Optionally, in this embodiment, the connecting structure 4111 is one of a cylinder or a slot. It can also be understood that, in the moving blade 411 and the hub 2, one of them is provided with a column body, and the other is provided with a clamping groove, so that the column body can be inserted into the clamping groove and clasped with the column body, thereby realizing the installation of the moving blade 411 and improving the assembly efficiency of the moving blade 411. In other embodiments, the connecting structure 4111 may also be a flange, and the moving blade 411 can be easily detached by flange connection.

It should be noted that the foregoing is only a preferred embodiment of the present application and the technical principles employed. Those skilled in the art will appreciate that the present embodiments are not limited to the specific embodiments described herein, and that various obvious changes, adaptations, and substitutions are possible, without departing from the scope of the present embodiments. Therefore, although the embodiments of the present application are described in more detail by the above examples, the embodiments of the present application are not limited to the above examples, and many other equivalent embodiments can be included without departing from the concept of the embodiments of the present application, and the scope of the embodiments of the present application is determined by the scope of the appended claims.

Claims (10)

1. A turbomolecular pump, comprising:

a pump housing (1);

at least four wheel hubs (2), at least four wheel hubs (2) being rotatably arranged in the pump housing (1);

at least four stages of impeller sets (4), wherein each impeller set (4) comprises movable impellers (41) and static impellers (42), the movable impellers (41) of at least four stages of impeller sets (4) are correspondingly arranged on at least four hubs (2) one by one, the static impellers (42) are fixedly arranged in the pump shell (1), and the movable impellers (41) and the static impellers (42) are alternately arranged along the airflow direction; the rotor blade wheel (41) comprises a plurality of rotor blades (411), the rotor blades (411) are airfoil-shaped blades, and the ratio of the outer diameter of the hub (2) to the outer diameter of the corresponding rotor blade wheel (41) is in the range of 0.4-0.7; the compression ratio of the single-stage impeller set (4) ranges from 1.4 to 2;

and the driving piece (3) is used for driving at least four hubs (2) to synchronously rotate.

2. The turbomolecular pump according to claim 1, wherein the distances between the stationary impeller (42) and the movable impeller (41) in the same impeller set (4) increase in order from the root of the moving blade (411) toward the tip.

3. Turbomolecular pump according to claim 1, wherein at least four hubs (2) are arranged on the same shaft, which is connected to the drive element (3).

4. Turbomolecular pump according to claim 1, further comprising a fairing (5), the fairing (5) being arranged at the gas flow inlet of the pump housing (1).

5. Turbomolecular pump according to claim 1, further comprising a diffuser (6), wherein the diffuser (6) is arranged at the gas flow outlet of the pump housing (1).

6. Turbomolecular pump according to claim 1, characterized in that the compression ratio of the impeller assembly (4) of a single stage is in the range of 1.4-1.6.

7. The turbomolecular pump of claim 1, wherein the stationary vane wheel (42) comprises a plurality of stationary vanes (421), the stationary vanes (421) being of a cambered plate-shaped structure.

8. Turbomolecular pump according to claim 1, wherein the rotor blades (411) are provided with connecting structures (4111), the connecting structures (4111) being fixedly connected to the corresponding hub (2).

9. Turbomolecular pump according to any of claims 1 to 8, characterized in that the angle of incidence of the moving blades (411) of the moving blades (41) of the impeller set (4) is the same for at least four stages, and the outer diameter of the moving blades (41) of the impeller set (4) decreases stepwise for at least four stages, in the direction of the gas flow.

10. Turbomolecular pump according to any of claims 1 to 8, characterized in that the setting angle of the moving blades (411) of the moving blades (41) of at least four stages of the impeller sets (4) decreases stepwise and the inner diameter of the moving blades (41) of at least four stages of the impeller sets (4) is the same or increases stepwise and the outer diameter of the moving blades (41) is the same in the gas flow direction.

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