Compound molecular pump

Abstract

The utility model relates to a compound molecular pump which comprises a rotor and a stator, the rotor comprises a turbine part, a transition part and a traction part which are sequentially arranged in the first direction, the traction part and the transition part are sleeved with the stator, the rotor is configured to rotate around the axis parallel to the first direction relative to the stator, and the turbine part and the transition part are arranged in the radial direction of the rotor. The stator is provided with a guide part spaced from the transition part, the size of the turbine part is larger than that of the transition part in the radial direction of the rotor, and a flow guide air channel is defined by the guide part, the turbine part and the transition part. According to the composite molecular pump, pumping speed transition between the turbine part and the traction part is promoted through the transition part and the guide part, and the overall pumping performance of the composite molecular pump is improved.

Description

Technical Field

[0001] The present application relates to the technical field of molecular pumps, and in particular to a compound molecular pump. Background Art

[0002] Molecular pump is a vacuum pump that uses a high-speed rotating rotor to transfer momentum to gas molecules, so that they obtain a directional speed, so that the gas is compressed and driven to the exhaust port to be pumped away by the front stage. There are two main types of molecular pumps, turbomolecular pumps and drag molecular pumps. Among them, the turbomolecular pump has the characteristics of high pumping speed and low compression ratio. In order to ensure that it can continuously exhaust a large amount of air under high pressure environment, the turbomolecular pump and the drag molecular pump are combined in series to form a compound molecular pump, which broadens the working pressure range. The compound molecular pump can obtain a large compression ratio while obtaining a large pumping speed, so it is widely used.

[0003] However, the compound molecular pump in the related art has a problem of poor overall pumping performance due to the large difference in pumping speed between the turbo molecular pump and the drag molecular pump. Utility Model Content

[0004] Based on this, a compound molecular pump is provided to improve the overall pumping performance of the compound molecular pump.

[0005] A compound molecular pump, comprising:

[0006] A rotor, comprising a turbine portion, a transition portion, and a traction portion arranged in sequence along a first direction; and

[0007] A stator, sleeved outside the traction portion and the transition portion, wherein the rotor is configured to be rotatable relative to the stator around an axis parallel to the first direction;

[0008] Along the radial direction of the rotor, the stator has a guide portion spaced apart from the transition portion;

[0009] Along the radial direction of the rotor, the size of the turbine part is larger than the size of the transition part, and the guide part, the turbine part and the transition part surround a guide air duct.

[0010] In one embodiment, the guide portion has a guide surface arranged toward the transition portion and at an angle to the first direction, and in the first direction and along the transition portion pointing to the turbine portion, a distance between the guide surface and the rotor along the radial direction of the rotor gradually increases.

[0011] In one embodiment, an angle θ between the guide surface and the first direction satisfies: 70°≤θ≤75°.

[0012] In one embodiment, the stator further includes a cylinder, which is connected to a side of the guide portion away from the turbine portion along the first direction, and the orthographic projection of the guide surface on a plane perpendicular to the first direction is configured as an annular figure, and the radius R1 of the annular figure and the radius R2 of the cylinder satisfy: 5 / 4R2≤R1≤3 / 2R2.

[0013] In one embodiment, the turbine portion includes a turbine body and a multi-stage blade tooth array, and the multi-stage blade tooth array is sequentially arranged on the turbine body along the first direction;

[0014] The blade tooth array includes a plurality of blade teeth, and the plurality of blade teeth are arranged on the turbine body around an axis parallel to the first direction.

[0015] In one of the embodiments, in the first direction and along the direction of the transition portion pointing to the turbine portion, the blade teeth in the multi-stage blade tooth array gradually increase in size in the radial direction of the turbine body.

[0016] In one embodiment, the blade tooth array closest to the transition portion along the first direction is defined as a first-stage blade tooth array;

[0017] The transition portion includes a plurality of transition blade teeth, and the plurality of transition blade teeth are arranged around an axis parallel to the first direction between the turbine portion and the traction portion;

[0018] Along the radial direction of the turbine body, a size S1 of the first blade teeth in the first-stage blade tooth array and a size L of the transition blade teeth satisfy 1 / 2S1≤L≤2 / 3S1.

[0019] In one embodiment, the multi-stage blade tooth array includes a second-stage blade tooth array, a third-stage blade tooth array and a fourth-stage blade tooth array, and along the first direction, the second-stage blade tooth array, the third-stage blade tooth array and the fourth-stage blade tooth array are sequentially arranged on a side of the first-stage blade tooth array away from the transition portion;

[0020] Along the radial direction of the turbine body, the size S2 of the second blade teeth in the second-stage blade tooth array, the size S3 of the third blade teeth in the third-stage blade tooth array, and the size S4 of the fourth blade teeth in the fourth-stage blade tooth array satisfy:

[0021] S2=S3=S4; and

[0022] 1 / 2S2≤S1≤4 / 5S2.

[0023] In one embodiment, the multi-stage blade tooth array further includes a fifth-stage blade tooth array, a sixth-stage blade tooth array, a seventh-stage blade tooth array and an eighth-stage blade tooth array, which are sequentially arranged along the first direction on a side of the fourth-stage blade tooth array away from the first-stage blade tooth array;

[0024] Along the radial direction of the turbine body, a size S5 of the fifth blade tooth in the fifth-stage blade tooth array, a size S6 of the sixth blade tooth in the sixth-stage blade tooth array, a size S7 of the seventh blade tooth in the seventh-stage blade tooth array, and a size S8 of the eighth blade tooth in the eighth-stage blade tooth array satisfy:

[0025] S8:S7:S6:S5:S4=1:0.9:0.7:0.6:0.45.

[0026] In one of the embodiments, a plurality of spiral grooves extending circumferentially along the first direction are protruded from the inner side surface of the stator facing the rotor.

[0027] The compound molecular pump has a transition portion between the turbine portion and the traction portion, and a guide portion at a position of the stator relative to the transition portion, thereby promoting the transition of the pumping speed between the turbine portion and the traction portion through the transition portion and the guide portion, thereby improving the overall pumping performance of the compound molecular pump. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a cross-sectional view of the compound molecular pump of this application.

[0029] Figure 2 for Figure 1 Enlarged view of point A in the middle.

[0030] Figure 3 This is a schematic diagram of the structure of the rotor of this application.

[0031] Figure 4 This is a schematic diagram of the structure of the stator of this application.

[0032] Figure 5 This is a cross-sectional view of the stator of this application.

[0033] Description of reference numerals:

[0034] 10. Compound molecular pump;

[0035] 100, rotor; 110, turbine part; 111, first-stage blade tooth array; 112, second-stage blade tooth array; 113, third-stage blade tooth array; 114, fourth-stage blade tooth array; 115, fifth-stage blade tooth array; 116, sixth-stage blade tooth array; 117, seventh-stage blade tooth array; 118, eighth-stage blade tooth array; 119, turbine body; 120, traction part;

[0036] 200, stator; 210, guide surface; 220, cylinder; 230, spiral groove;

[0037] 300, transition portion; 310, transition blade teeth;

[0038] F1, first direction. DETAILED DESCRIPTION

[0039] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0040] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0041] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0042] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0043] In the present application, unless otherwise clearly specified and limited, a first feature being “above” or “below” a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being “above”, “above”, and “above” a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being “below”, “below”, and “below” a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0044] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used herein are for illustrative purposes only and do not represent the only implementation method.

[0045] In vacuum equipment, molecular pumps have been widely used in semiconductor, pharmaceutical, chemical, aerospace and other industries. There are two main types of molecular pumps at present, turbomolecular pumps and traction molecular pumps. Among them, turbomolecular pumps have the characteristics of high pumping speed and low compression ratio. In order to ensure that they can continuously exhaust a large amount of air under high pressure environment, turbomolecular pumps and traction molecular pumps are combined in series to form a compound molecular pump, which broadens the working pressure range. Compound molecular pumps can obtain a large compression ratio while obtaining a large pumping speed, so they are widely used.

[0046] At present, there are two main types of compound molecular pumps, one is a combination of a turbomolecular pump and a disc-type traction molecular pump, and the other is a combination of a turbomolecular pump and a barrel-type traction molecular pump, and the latter is more common. However, the above two types of compound molecular pumps in the related art both have the problem of low pumping efficiency at the junction of the turbine part and the traction part of the compound molecular pump. The turbine part has a large pumping area and a high pumping speed, while the traction part has a small groove area and a low pumping speed. The mismatch in pumping speed between the above two causes the gas to increase in disorder when it flows from the turbine part to the traction part, which aggravates the backflow phenomenon and limits the improvement of the overall pumping performance of the compound molecular pump.

[0047] Based on the above problems, the present application provides a compound molecular pump 10 to improve the overall pumping performance of the compound molecular pump 10 .

[0048] like Figure 1 and Figure 2As shown, the compound molecular pump 10 provided in the present application includes a rotor 100 and a stator 200, the rotor 100 includes a turbine part 110, a transition part 300 and a traction part 120 arranged in sequence along a first direction F1, the stator 200 is sleeved outside the traction part 120 and the transition part 300, the rotor 100 is configured to be able to rotate relative to the stator 200 around an axis parallel to the first direction F1, and the rotor 100 and the stator 200 rotate relative to each other to achieve the function of pumping air and pressure of the compound molecular pump 10. It can be understood that the rotor 100 of the present application is installed on the driving shaft, and the driving shaft drives the rotor 100 to rotate under the drive of the driving member.

[0049] Along the radial direction of the rotor 100, the stator 200 has a guide portion spaced apart from the transition portion 300. Along the radial direction of the rotor 100, the size of the turbine portion 110 is larger than the size of the transition portion 300, and a guide air duct is surrounded by the guide portion, the turbine portion 110, and the transition portion 300. The size of the turbine portion 110 is larger than the size of the transition portion 300, which can be understood as follows: along the radial direction of the rotor 100, the size of the turbine portion 110 at each location along the first direction F1 is larger than the size of the transition portion 300, so that along the radial direction of the rotor 100, the size of the multi-stage blade tooth array included in the turbine portion 110 is larger than the size of the transition portion 300.

[0050] Understandably, combined Figure 3 As shown, the turbine part 110 has a large pumping area and a high pumping speed, while the traction part 120 has a small groove area and a low pumping speed. The present application sets a transition part 300 and a guide part spaced from the transition part 300, so that the transition part 300 and the guide part can play a guiding transition role, thereby avoiding the mismatch between the turbine part 110 and the traction part 120 due to the large difference in size and pumping speed, which leads to an increase in the disorder of the gas when it flows from the turbine part 110 to the traction part 120, aggravating the backflow phenomenon and limiting the overall pumping performance of the compound molecular pump 10. That is, the compound molecular pump 10 of the present application promotes the pumping speed transition between the turbine part 110 and the traction part 120 through the setting of the transition part 300 and the guide part, thereby improving its overall pumping performance.

[0051] Continue reading Figure 1 , combined with reference Figure 4 As shown, the guide portion has a guide surface 210 disposed toward the transition portion 300 and disposed at an angle to the first direction F1. In the first direction F1 and along the transition portion 300 pointing to the turbine portion 110, the distance between the guide surface 210 and the rotor 100 along the radial direction of the rotor gradually increases. The flow area between the guide surface 210 and the rotor 100 gradually changes, and the pumping speed at the outlet of the turbine portion 110 of the compound molecular pump 10 is slightly reduced to match the inlet pumping speed of the traction portion 120, so as to reduce the backflow phenomenon.

[0052] In some embodiments, the angle θ between the guide surface 210 and the first direction F1 satisfies: 70°≤θ≤75°. The setting of the guide surface 210 expands the opening of the traction part 120 toward the turbine part 110, improves the air extraction performance of the traction part 120, and facilitates smoother introduction of air flow at the connection between the traction part 120 and the turbine part 110.

[0053] See also Figure 4 and Figure 5 The stator 200 further includes a cylinder 220, which is connected to the side of the guide portion away from the turbine portion 110 along the first direction F1. The positive projection of the guide surface 210 on the plane perpendicular to the first direction F1 is a ring-shaped figure. The radius R1 of the ring-shaped figure and the radius R2 of the cylinder 220 satisfy: 5 / 4R2≤R1≤3 / 2R2, that is, the guide portion is arranged around the cylinder 220 along the axis parallel to the first direction F1, and along the radial direction of the cylinder 220, the size of the guide portion is larger than the size of the cylinder 220, so the guide portion is arranged on the side of the cylinder 220 facing the turbine portion 110 to play a transition guide role. It can be understood that the radius R1 of the ring-shaped figure refers to the radius of each concentric circle constituting the ring-shaped figure.

[0054] Combined with reference Figure 1 and Figure 3 As shown, the turbine part 110 includes a turbine body 119 and a multi-stage blade tooth array, the multi-stage blade tooth array is sequentially arranged on the turbine body 119 along the first direction F1, the rotation of the turbine body 119 drives the multi-stage blade tooth array to rotate to pump gas, and the blade tooth array includes a plurality of blade teeth, and the plurality of blade teeth are arranged on the turbine body 119 around an axis parallel to the first direction F1. Through the arrangement of the blade teeth on the multi-stage blade tooth array, when the compound molecular pump 10 is working, the gas can be quickly pumped to achieve the purpose of pumping gas.

[0055] In some embodiments, in the first direction F1, and in the direction from the transition portion 300 to the turbine portion 110, the blade teeth in the multi-stage blade tooth array gradually increase in radial dimension in the turbine body 119. In other words, in the direction from the turbine portion 110 to the transition portion 300, the blade teeth in the multi-stage blade tooth array gradually decrease in radial dimension in the turbine body 119, thereby being able to gradually and slightly reduce the air extraction speed of the turbine portion 110 toward the transition portion 300, so that the air extraction speed gradually matches the air inlet of the traction portion 120 or the air inlet of the guide air duct surrounded by the guide portion, the turbine portion 110 and the transition portion 300, so as to reduce the backflow phenomenon.

[0056] The transition portion 300 includes a plurality of transition blade teeth 310, and the plurality of transition blade teeth 310 are arranged between the turbine portion 110 and the traction portion 120 around an axis parallel to the first direction F1. The transition portion 300 is arranged at a position opposite to the guide portion, and is provided with transition blade teeth 310 that can drive gas pumping, thereby increasing the gas pumping speed at the air inlet of the traction portion 120 or the guide air duct, so that the air inlet of the traction portion 120 has a relatively large pumping speed, which can better adapt to the pumping speed of the turbine portion 110.

[0057] Combined with reference Figure 2 and Figure 3 As shown, the blade tooth array closest to the transition part 300 along the first direction F1 is defined as the first-stage blade tooth array 111, and along the radial direction of the turbine body 119, the size S1 of the first blade tooth in the first-stage blade tooth array 111 and the size L of the transition blade tooth 310 satisfy 1 / 2S1≤L≤2 / 3S1. The size of the transition blade tooth 310 is smaller than the size of the first blade tooth in the first-stage blade tooth array 111, and is in a suitable range relationship with the size of the first blade tooth, so that the pumping speed of the gas flowing from the turbine part 110 toward the transition part 300 can be gradually reduced, and the pumping speed of the traction part 120 can be better matched.

[0058] The air extraction rate of the transition part 300 is about 1 / 2-2 / 3 of the air extraction rate of the first-stage blade tooth array 111. The transition part 300 not only plays the role of pulling gas and gradually weakening the extraction rate to adapt to the extraction rate of the traction part 120, but also can ensure that there is a large extraction rate at the air inlet of the traction part 120 or the air inlet of the guide air duct, thereby improving the overall extraction efficiency. The setting of the guide part on the stator 200 makes the extraction rate at the air inlet of the guide air duct surrounded by the guide part, turbine part 110 and transition part 300, which is 1 / 2-3 / 5 of the extraction rate of the first-stage blade tooth array 111. The combination of the setting of the transition part 300 and the guide part can greatly improve the extraction rate at the air inlet of the guide air duct, making the airflow at the connection between the turbine part 110 and the traction part 120 smoother.

[0059] The multi-stage blade tooth array further includes a second-stage blade tooth array 112, a third-stage blade tooth array 113 and a fourth-stage blade tooth array 114. Along the first direction F1, the second-stage blade tooth array 112, the third-stage blade tooth array 113 and the fourth-stage blade tooth array 114 are sequentially arranged on a side of the first-stage blade tooth array 111 away from the transition portion 300. Along the radial direction of the turbine body 119, the size S2 of the second blade teeth in the second-stage blade tooth array 112, the size S3 of the third blade teeth in the third-stage blade tooth array 113 and the size S4 of the fourth blade teeth in the fourth-stage blade tooth array 114 satisfy:

[0060] S2=S3=S4; and

[0061] 1 / 2S2≤S1≤4 / 5S2.

[0062] That is, the size of the second blade teeth in the second blade tooth array and the size of the first blade teeth in the first-stage blade tooth array 111 are still gradually increasing, or in other words, the size of the first blade teeth in the first-stage blade tooth array 111 and the size of the second blade teeth in the second blade tooth array are gradually decreasing. Gradually reducing the blade tooth size and gradually changing the flow area of ​​the gas at each level of the blade tooth array are beneficial to gradually reducing the gas pumping speed near the traction part 120 to weaken the backflow phenomenon.

[0063] The size of the second blade teeth in the second-stage blade tooth array 112, the size of the third blade teeth in the third-stage blade tooth array 113 and the size of the fourth blade teeth in the fourth-stage blade tooth array 114 are the same, which can ensure that the overall pumping speed of the turbine part 110 is less affected, and the overall pumping speed of the turbine part 110 or the pumping airflow is not adversely affected. On this basis, combined with the size of the first blade teeth in the first-stage blade tooth array 111 and the gradually reduced size of the transition blade teeth 310 of the transition part 300, it can ensure that the overall pumping effect of the turbine part 110 is better, and can ensure that the pumping speed of the turbine part 110 toward the traction part 120 and the pumping speed of the traction part 120 toward the turbine part 110 are adapted, which is conducive to the transition of gas between the two.

[0064] The multi-stage blade tooth array further includes a fifth-stage blade tooth array 115, a sixth-stage blade tooth array 116, a seventh-stage blade tooth array 117 and an eighth-stage blade tooth array 118 which are sequentially arranged along the first direction F1 on the side of the fourth-stage blade tooth array 114 away from the first-stage blade tooth array 111. Along the radial direction of the turbine body 119, the size S5 of the fifth blade tooth in the fifth-stage blade tooth array 115, the size S6 of the sixth blade tooth in the sixth-stage blade tooth array 116, the size S7 of the seventh blade tooth in the seventh-stage blade tooth array 117 and the size S8 of the eighth blade tooth in the eighth-stage blade tooth array 118 satisfy:

[0065] S8:S7:S6:S5:S4=1:0.9:0.7:0.6:0.45.

[0066] The radial size of the blade teeth of the multi-stage blade tooth array decreases step by step, and the pumping speed of the turbine part 110 for the gas also decreases slowly step by step, which is conducive to the step-by-step transition of the gas flow and will not destroy the balance of the gas flow. Combined with the same radial size of the blade teeth in the middle part, the turbine part 110 has better pumping performance as a whole. Combined with the settings of the transition part 300 and the guide part, the airflow from the turbine part 110 to the traction part 120 has a better transition, so that the overall pumping performance of the compound molecular pump 10 of the present application is better.

[0067] In some embodiments, Figure 5As shown, the inner side surface of the stator 200 facing the rotor 100 is provided with a plurality of spiral grooves 230 extending circumferentially along the first direction F1 for guiding the flow of gas entering the traction portion 120 and pumping the gas when the stator 200 and the rotor 100 rotate relative to each other.

[0068] The compound molecular pump 10 of the present application promotes the transition of the pumping speed between the turbine part 110 and the traction part 120 by designing the transition part 300 between the turbine part 110 and the traction part 120 and the guide part of the stator 200 toward the turbine part 110, so that the side of the turbine part 110 toward the traction part 120 is better adapted to the pumping speed of the traction part 120. At the same time, the guide part is equivalent to expanding the air inlet of the traction part 120 toward the turbine part 110, so that the traction part 120 is better adapted to the turbine part 110, thereby improving the overall pumping performance of the compound molecular pump 10.

[0069] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0070] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the utility model patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims.

Claims

1. A compound molecular pump, characterized in that: The compound molecular pump comprises: A rotor, comprising a turbine portion, a transition portion, and a traction portion arranged in sequence along a first direction; and A stator, sleeved outside the traction portion and the transition portion, wherein the rotor is configured to be rotatable relative to the stator around an axis parallel to the first direction; Along the radial direction of the rotor, the stator has a guide portion spaced apart from the transition portion; Along the radial direction of the rotor, the size of the turbine part is larger than the size of the transition part, and the guide part, the turbine part and the transition part surround a guide air duct.

2. The compound molecular pump according to claim 1, characterized in that: The guide portion has a guide surface disposed toward the transition portion and at an angle to the first direction. In the first direction and along the transition portion pointing toward the turbine portion, a distance between the guide surface and the rotor along the radial direction of the rotor gradually increases.

3. The compound molecular pump according to claim 2, characterized in that: An included angle θ between the guide surface and the first direction satisfies: 70°≤θ≤75°.

4. The compound molecular pump according to claim 2, characterized in that: The stator also includes a cylinder, which is connected to a side of the guide portion away from the turbine portion along the first direction. The orthographic projection of the guide surface on a plane perpendicular to the first direction is configured as an annular figure, and the radius R1 of the annular figure and the radius R2 of the cylinder satisfy: 5 / 4R2≤R1≤3 / 2R2.

5. The compound molecular pump according to claim 1, characterized in that: The turbine part comprises a turbine body and a multi-stage blade tooth array, wherein the multi-stage blade tooth array is sequentially arranged on the turbine body along the first direction; The blade tooth array includes a plurality of blade teeth, and the plurality of blade teeth are arranged on the turbine body around an axis parallel to the first direction.

6. The compound molecular pump according to claim 5, characterized in that: In the first direction and in the direction along the transition portion pointing to the turbine portion, the sizes of the blade teeth in the multiple stages of blade tooth arrays in the radial direction of the turbine body gradually increase.

7. The compound molecular pump according to claim 1, characterized in that: The inner side surface of the stator facing the rotor is protruded with a plurality of spiral grooves extending circumferentially along the first direction.

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