Molecular pump

Abstract

The molecular pump comprises an impeller, a connecting disc and a rotating shaft, the impeller is provided with a penetrating through hole, the through hole comprises a low-pressure cavity part, a connecting cavity part and a high-pressure cavity part which are distributed in the axial direction, and the inner diameter of the connecting cavity part is smaller than that of the high-pressure cavity part and that of the low-pressure cavity part; an annular fixing part is formed between the low-pressure cavity part and the high-pressure cavity part, and at least one sealing piece is arranged at the contact position of the impeller and the rotating shaft and / or the connecting disc. The connecting disc comprises a balance part and a connecting part, the connecting disc is of an integrated structure, the balance part at least partially covers the low-pressure cavity part, the balance part is fixedly connected with the fixing part, the connecting part extends into the connecting cavity part, and the inner side wall of the connecting part abuts against the inner side wall of the connecting cavity part; the rotating shaft is arranged in the high-pressure cavity part and fixedly connected with the fixing part. At least one sealing piece is arranged at the contact position of the impeller and the rotating shaft and / or the connecting disc, airflow leakage between the high-pressure cavity part and the low-pressure cavity part can be isolated, and therefore the vacuumizing performance of the molecular pump can be effectively improved.

Description

Technical Field

[0001] The embodiments of this specification relate to the technical field of molecular pumps, and particularly to a molecular pump. Background Art

[0002] A molecular pump is a momentum transfer type vacuum pump that uses a high-speed rotating impeller to transfer momentum to gas molecules, causing the gas to flow in a directional manner for pumping. It is widely used in scientific instruments and industrial production equipment.

[0003] Currently, the installation structures of the impeller and the rotor of a molecular pump are mainly divided into through-hole locking and impeller closed locking. The difference between the two forms lies in whether there is a through-hole that penetrates the high and low pressure regions inside and outside the impeller at the installation position of the impeller and the rotor. The closed type can effectively isolate the high and low pressure regions inside and outside the impeller, avoid vacuum pressure leakage, and ensure the molecular aerodynamic performance. However, the internal limiting structure of the closed structure is not easy to machine and measure, and the manufacturing difficulty is relatively large. The open structure is easy to machine and measure, but the through-hole structure will cause air leakage between the high and low pressure regions, resulting in poor sealing performance and affecting the overall pumping performance of the molecular pump.

[0004] In view of the above problems, no effective solution has been proposed yet. Utility Model Content

[0005] The embodiments of this specification provide a molecular pump to solve the problem of poor sealing performance in the existing open structure.

[0006] The embodiments of this specification provide a molecular pump, including: an impeller, an adapter plate, and a rotating shaft. Among them, the impeller has a through-hole, and the through-hole includes a low-pressure cavity part, a connection cavity part, and a high-pressure cavity part distributed along the axial direction. The inner diameter of the connection cavity part is smaller than the inner diameters of the high-pressure cavity part and the low-pressure cavity part. An annular fixing part is formed between the low-pressure cavity part and the high-pressure cavity part. At least one sealing member is provided at the contact between the impeller and the rotating shaft and / or the adapter plate; the adapter plate includes a balance part and a connection part. The adapter plate is an integral structure. The balance part at least partially covers the low-pressure cavity part, and the balance part is fixedly connected to the fixing part. The connection part extends into the connection cavity part, and the inner side wall of the connection part abuts against the inner side wall of the connection cavity part; the rotating shaft is arranged in the high-pressure cavity part, and the rotating shaft is fixedly connected to the fixing part.

[0007] In an embodiment of the present application, the impeller and the adapter plate are press-fitted.

[0008] In an embodiment of the present application, the connecting portion includes a cylindrical portion and a first convex portion that are axially distributed. One end face of the rotating shaft close to the connecting cavity portion has a first concave portion that matches the first convex portion. The cylindrical portion penetrates through the connecting cavity portion, and the first concave portion and the first convex portion are in clearance fit to make the rotating shaft, the impeller, and the connecting disk concentric; or, one end of the connecting portion close to the high-pressure cavity portion has a second concave portion, and one end face of the rotating shaft close to the connecting cavity portion has a second convex portion that matches the second concave portion. The second concave portion and the second convex portion are in clearance fit to make the rotating shaft, the impeller, and the connecting disk concentric.

[0009] In an embodiment of the present application, after installation, the mating surface of the connecting portion is flush with the lower surface of the fixing portion, and the mating surface of the connecting portion, the lower surface of the fixing portion, and the mounting surface of the rotating shaft are in contact; the mating surface of the connecting portion is the end face that contacts the mounting surface of the rotating shaft.

[0010] In an embodiment of the present application, the clearance between the first concave portion and the first convex portion or the clearance between the second concave portion and the second convex portion is 0 to 0.02 mm on one side.

[0011] In an embodiment of the present application, the fixing portion is provided with a plurality of first fixing holes and a plurality of second fixing holes. Among them, the plurality of first fixing holes and the plurality of second fixing holes are blind holes; the balancing portion and the fixing portion are fixedly connected through a plurality of first locking members and the plurality of first fixing holes; the rotating shaft and the fixing portion are fixedly connected through a plurality of second locking members and the plurality of second fixing holes.

[0012] In an embodiment of the present application, at least one sealing member is provided at the contact portion between the fixing portion and the rotating shaft and / or the connecting disk inside the plurality of first fixing holes and the plurality of second fixing holes.

[0013] In an embodiment of the present application, at least one sealing member is provided on the lower surface of the fixing portion inside the second fixing hole.

[0014] In an embodiment of the present application, at least one sealing groove is provided at the contact portion between the fixing portion and the rotating shaft and / or the connecting disk, and the sealing member is arranged in the sealing groove.

[0015] In an embodiment of the present application, the sealing member includes an O-ring.

[0016] An embodiment of this specification provides a molecular pump. The impeller can adopt an open structure with an opening, and the through holes of the impeller can include a low-pressure cavity part, a connection cavity part, and a high-pressure cavity part that are sequentially connected. To facilitate the fixation of the connection disk and the rotating shaft, the inner diameter of the connection cavity part can be smaller than the inner diameters of the low-pressure cavity part and the high-pressure cavity part, so that an annular fixing part can be formed between the low-pressure cavity part and the high-pressure cavity part. The connection disk can include a balance part and a connection part. The balance part can make the molecular pump have higher dynamic balance accuracy. The balance part can at least partially cover the low-pressure cavity part, and the balance part can be fixedly connected to the fixing part, so that the vibration during operation can be effectively reduced. The connection part can extend into the connection cavity part, and the inner side wall of the connection part can be in contact with the inner side wall of the connection cavity part, so that the impeller and the connection disk can be concentrically arranged, and further the eccentricity during operation can be reduced. The balance part and the connection part can be of an integral structure, thus effectively improving the machinability of parts, the convenience of measurement, and the operability of the overall machine installation, and reducing the overall manufacturing process difficulty and cost. The rotating shaft can be arranged in the high-pressure cavity part, and the rotating shaft is fixedly connected to the fixing part, so that the rotating shaft and the impeller can be concentrically arranged. Since the high-pressure cavity part is the high-pressure area of the impeller and the low-pressure cavity part is the low-pressure area of the impeller, the gas in the high-pressure area will flow to the low-pressure area during the operation of the molecular pump, resulting in vacuum pressure leakage. Therefore, at least one seal can be provided at the contact between the impeller and the rotating shaft and / or the connection disk. By providing the seal, the air flow leakage between the high-pressure cavity part and the low-pressure cavity part can be isolated, so that the vacuum pumping performance of the molecular pump can be effectively improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on the structures shown in these drawings.

[0018] Figure 1 is an exploded view of the molecular pump provided according to the embodiment of this specification;

[0019] Figure 2 is a cross-sectional view of the impeller provided according to the embodiment of this specification;

[0020] Figure 3 is a schematic structural view of the fixing part provided according to the embodiment of this specification;

[0021] Figure 4 is a partial schematic view of the impeller showing the position where the seal line is provided according to the embodiment of this specification;

[0022] Figure 5It is a partial schematic view of a fitting structure between a connecting portion and a rotating shaft provided according to an embodiment of this specification;

[0023] Figure 6 It is a partial schematic view of another fitting structure between a connecting portion and a rotating shaft provided according to an embodiment of this specification;

[0024] Figure 7 It is a partial schematic view of another fitting structure between a connecting portion and a rotating shaft provided according to an embodiment of this specification;

[0025] Figure 8 It is a partial schematic view of another fitting structure between a connecting portion and a rotating shaft provided according to an embodiment of this specification;

[0026] Figure 9 It is a cross-sectional view of a molecular pump provided according to an embodiment of this specification;

[0027] Figure 10 It is a partial schematic view of a sealing groove provided according to an embodiment of this specification.

[0028] The realization of the purpose of this application, functional features and advantages will be further described with reference to the embodiments and the accompanying drawings. Specific Embodiments

[0029] The principles and spirit of the embodiments of this specification will be described below with reference to several exemplary embodiments. It should be understood that these embodiments are given only to enable those skilled in the art to better understand and then implement the embodiments of this specification, and do not limit the scope of the embodiments of this specification in any way. On the contrary, these embodiments are provided to make the disclosure of the embodiments of this specification more thorough and complete, and to be able to convey the scope of this disclosure fully to those skilled in the art.

[0030] It should be noted that when an element is referred to as "disposed on" another element, it can be directly on the other element or there may also be an intermediate element. When an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be an intermediate element at the same time. All directional indication terms herein (such as up, down, left, right, front, back, vertical, horizontal...) are only used to explain the relative position relationship and movement conditions between components in a certain specific posture (as shown in the drawings). If this specific posture changes, then the directional indication also changes accordingly, and it does not represent the only embodiment.

[0031] In addition, the descriptions involving "first", "second", etc. in this application are only for descriptive purposes and should not be construed as indicating or implying their relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In addition, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this utility model pertains. The terms used in the specification of this utility model herein are only for the purpose of describing specific embodiments and are not intended to limit this utility model. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0032] Please refer to Figure 1 and Figure 2 , this embodiment can provide a molecular pump. The molecular pump may include: an impeller 1, an adapter plate 2, and a rotating shaft 3. Among them, the impeller 1 has a through-hole, and the through-hole includes a low-pressure cavity portion 11, a connection cavity portion 12, and a high-pressure cavity portion 13 distributed along the axial direction. The inner diameter of the connection cavity portion 12 is smaller than the inner diameters of the low-pressure cavity portion 11 and the high-pressure cavity portion 13. An annular fixing portion 14 is formed between the low-pressure cavity portion 11 and the high-pressure cavity portion 13. At least one seal is provided at the contact between the impeller 1 and the rotating shaft 3 and / or the adapter plate 2; the adapter plate 2 includes a balance portion 21 and a connection portion 22. The adapter plate 2 is an integral structure. The balance portion 21 at least partially covers the low-pressure cavity portion 11. The balance portion 21 is fixedly connected to the fixing portion 14. The connection portion 22 extends into the connection cavity portion 12, and the inner side wall of the connection portion 22 abuts against the inner side wall of the connection cavity portion 12; the rotating shaft 3 is disposed in the high-pressure cavity portion 13, and the rotating shaft 3 is fixedly connected to the fixing portion 14.

[0033] In this embodiment, the impeller 1 may be an open structure with an opening. The through-hole of the impeller 1 may include three parts: a low-pressure cavity portion 11, a connection cavity portion 12, and a high-pressure cavity portion 13. The low-pressure cavity portion 11, the connection cavity portion 12, and the high-pressure cavity portion 13 are connected in sequence.

[0034] In this embodiment, the inner diameters of the low-pressure cavity portion 11, the connection cavity portion 12, and the high-pressure cavity portion 13 may be the same or different. In some embodiments, for the convenience of fixing the adapter plate 2 and the rotating shaft 3, as Figure 2 shown, the inner diameter of the connection cavity portion 12 may be smaller than the inner diameters of the low-pressure cavity portion 11 and the high-pressure cavity portion 13, so that an annular fixing portion 14 can be formed between the low-pressure cavity portion 11 and the high-pressure cavity portion 13. The inner through-hole of the annular fixing portion 14 is the connection cavity portion 12.

[0035] In this embodiment, the annular fixing portion 14 may be as Figure 3As shown by the dashed line in the figure, it can of course be understood that the fixing part can also be other possible shapes, such as: stepped shape, etc., and specifically can be determined according to the actual situation, and the embodiments of this specification do not limit this.

[0036] In this embodiment, the connecting disc 2 may include a balancing part 21 and a connecting part 22. The balancing part 21 can reduce the vibration during operation and enable the molecular pump to have higher dynamic balance accuracy. The balancing part 21 can at least partially cover the low-pressure cavity part. The balancing part 21 can be a disc structure, and of course it can be other possible shapes, such as: square, hexagon, irregular shape or matching the shape of the low-pressure cavity part 11. In order to improve the dynamic balance performance, weight holes can also be provided on the balancing part 21, and specifically can be set according to the actual situation, and the embodiments of this specification do not limit this.

[0037] In this embodiment, the balancing part 21 can be fixedly connected to the fixing part 14, so as to effectively reduce the vibration during operation. The balancing part 21 and the fixing part 14 can be locked and fixed by screws or bolts. Of course, it can be understood that they can also be fixed by other possible methods, such as: welding, riveting, thread pressing, glue adhesion, etc., and specifically can be selected according to the actual situation, and the embodiments of this specification do not limit this.

[0038] In this embodiment, the connecting part 22 can extend into the connecting cavity part 12, and the inner side wall of the connecting part 22 can be in contact with the inner side wall of the connecting cavity part 12, so that the impeller 1 and the connecting disc 2 can be concentrically arranged, and further the eccentricity during operation can be reduced.

[0039] In this embodiment, the connecting part 22 can be entirely extended into the connecting cavity part 12, but does not fill the entire connecting cavity part 12, and the connecting part 22 can also penetrate through the connecting cavity part 12. Further, the connecting part 22 can be in contact with one end of the rotating shaft, or can be non-contact with the rotating shaft, and specifically can be designed according to the actual situation, and the embodiments of this specification do not limit this.

[0040] In this embodiment, the balancing part 21 and the connecting part 22 can be an integral structure, thus effectively improving the machinability of parts, the convenience of measurement and the operability of the whole machine installation, and reducing the overall manufacturing process difficulty and cost.

[0041] In this embodiment, the rotating shaft 3 can be arranged in the high-pressure cavity part 13, and the rotating shaft 3 is fixedly connected to the fixing part 14, so that the rotating shaft and the impeller can be concentrically arranged. The rotating shaft 3 and the fixing part 14 can be locked and fixed by screws or bolts. Of course, it can be understood that they can also be fixed by other possible methods, such as: welding, riveting, thread pressing, glue adhesion, etc., and specifically can be selected according to the actual situation, and the embodiments of this specification do not limit this.

[0042] In this embodiment, one end of the rotating shaft 3 may not extend into the connection cavity portion 12, or one end may extend into the connection cavity portion 12. Among them, if the part of the rotating shaft 3 extending into the connection cavity portion 12 abuts against the inner side wall of the connection cavity portion 12, the concentricity between the impeller 1 and the rotating shaft 3 can be effectively improved, and then the concentricity between the rotating shaft 3 and the connection disk 2 can be effectively improved, thereby effectively reducing the eccentricity during operation.

[0043] In this embodiment, the balance portion 21 of the connection disk 2 can abut against the upper surface of the fixing portion 14, and the rotating shaft 3 abuts against the lower surface of the fixing portion 14. Among them, the above upper surface and lower surface are relative concepts. The upper surface can be the end face of the fixing portion 14 on the side of the low-pressure cavity portion 11, and the lower surface can be the end face of the fixing portion 14 on the side of the high-pressure cavity portion 13. Since the high-pressure cavity portion 13 is the high-pressure area of the impeller 1 and the low-pressure cavity portion 11 is the low-pressure area of the impeller 1, if the high and low pressure areas are not sealed and separated, the gas in the high-pressure area will flow to the low-pressure area during the operation of the molecular pump, resulting in vacuum pressure leakage. Therefore, at least one seal can be provided at the contact between the impeller and the rotating shaft and / or the connection disk.

[0044] In this embodiment, the seal can be provided at the contact between the impeller 1 and the rotating shaft 3 and / or the connection disk 2, and the position where the seal is provided can be as Figure 4 shown by the gray dotted line in the partial schematic diagram of the impeller. By providing the seal, the air flow leakage between the high-pressure cavity portion 13 and the low-pressure cavity portion 11 can be isolated, thereby effectively improving the vacuum pumping performance of the molecular pump.

[0045] In this embodiment, at least one seal can be provided. In order to improve the sealing performance, multiple seals can also be provided. Specifically, it can be selected according to the actual performance test results, and this embodiment of the specification does not limit this.

[0046] In this embodiment, the above-mentioned seal can adopt packing seal, labyrinth seal, oil seal, O-ring seal and other methods. Of course, the form of the seal is not limited to the above examples. Those skilled in the art may make other changes under the inspiration of the technical essence of this embodiment of the specification, but as long as the functions and effects achieved are the same or similar to those of this embodiment of the specification, they should all be covered within the protection scope of this embodiment of the specification.

[0047] From the above description, it can be seen that the embodiments of this specification achieve the following technical effects: The impeller can adopt an open structure with an opening, and the through hole of the impeller can include a low-pressure cavity portion, a connection cavity portion, and a high-pressure cavity portion that are sequentially connected. To facilitate the fixation of the connection disk and the rotating shaft, the inner diameter of the connection cavity portion can be smaller than the inner diameters of the low-pressure cavity portion and the high-pressure cavity portion, so that an annular fixing portion can be formed between the low-pressure cavity portion and the high-pressure cavity portion. The connection disk can include a balancing portion and a connection portion. The balancing portion can enable the molecular pump to have higher dynamic balance accuracy. The balancing portion can at least partially cover the low-pressure cavity portion, and the balancing portion can be fixedly connected to the fixing portion, thereby effectively reducing vibration during operation. The connection portion can extend into the connection cavity portion, and the inner side wall of the connection portion can abut against the inner side wall of the connection cavity portion, so that the impeller and the connection disk can be concentrically arranged, and further the eccentricity during operation can be reduced. The balancing portion and the connection portion can be of an integral structure, thereby effectively improving the machinability of parts, the convenience of measurement, and the operability of the overall machine installation, and reducing the overall manufacturing process difficulty and cost. The rotating shaft can be arranged in the high-pressure cavity portion, and the rotating shaft is fixedly connected to the fixing portion, so that the rotating shaft and the impeller can be concentrically arranged. Since the high-pressure cavity portion is the high-pressure area of the impeller and the low-pressure cavity portion is the low-pressure area of the impeller, the gas in the high-pressure area will flow to the low-pressure area during the operation of the molecular pump, resulting in vacuum pressure leakage. Therefore, at least one seal can be provided at the contact between the impeller and the rotating shaft and / or the connection disk. By providing the seal, the air flow leakage between the high-pressure cavity portion and the low-pressure cavity portion can be isolated, thereby effectively improving the vacuum pumping performance of the molecular pump.

[0048] In one embodiment, the impeller 1 can be press-fitted with the connection disk 2.

[0049] In this embodiment, in order to further improve the concentricity between the impeller and the connection disk and ensure that the impeller 1 can still maintain a tight fit with the connection disk 2 under the action of centrifugal force during operation, the impeller 1 can be press-fitted with the connection disk 2 to ensure that the concentricity after the connection disk and the impeller are assembled is the same as that of the closed type.

[0050] In this embodiment, the interference amount can be determined by calculating the overall centrifugal strength of the rotating shaft 3, and specifically can be determined according to the actual situation. The embodiments of this specification do not limit this.

[0051] In one embodiment, the connection portion 22 includes a cylindrical portion 221 and a first convex portion 222 that are axially distributed. One end face of the rotating shaft 3 close to the connection cavity portion 12 has a first concave portion 31 that matches the first convex portion 222. The cylindrical portion 221 penetrates through the connection cavity portion 12, and the first concave portion 31 and the first convex portion 222 are in clearance fit to make the rotating shaft 3, the impeller 1, and the connection disk 2 concentric; or,

[0052] One end of the connecting part 22 close to the high-pressure cavity part 13 has a second concave part 223, and one end face of the rotating shaft 3 close to the connecting cavity part 12 has a second convex part 32 matching the second concave part 223. The second concave part 223 and the second convex part 32 are in clearance fit to make the rotating shaft 3, the impeller 1 and the connecting disc 2 concentric.

[0053] In this embodiment, one end of the connecting disc 2 can be abutted against one end of the rotating shaft 3 and is in clearance fit through a boss, so as to effectively improve the concentricity among the rotating shaft 3, the impeller 1 and the connecting disc 2. The boss can be arranged on the connecting disc 2 or on the rotating shaft 3, and the embodiments of this specification do not limit this.

[0054] In a specific embodiment, as Figure 5 shown in partial view A, the cylindrical part 221 penetrates through the connecting cavity part 12, and the first convex part 222 extends out of the connecting cavity part. One end face of the rotating shaft 3 close to the connecting cavity part 12 has a first concave part 31 matching the first convex part 222. The first concave part 31 and the first convex part 222 are in clearance fit.

[0055] In a specific embodiment, as Figure 6 shown in partial view A, the cylindrical part 221 extends into the connecting cavity part 12, and the first convex part 222 is also located in the connecting cavity part 12. One end face of the rotating shaft 3 close to the connecting cavity part 12 has a first concave part 31 matching the first convex part 222. One end part of the rotating shaft 3 extends into the connecting cavity part 12 so that the first concave part 31 and the first convex part 222 are in clearance fit.

[0056] In a specific embodiment, as Figure 7 shown in partial view A, one end of the connecting part 22 close to the high-pressure cavity part 13 has a second concave part 223, and one end face of the rotating shaft 3 close to the connecting cavity part 12 has a second convex part 32 matching the second concave part 223. The second convex part 32 can extend into the connecting cavity part 12. Of course, it can be understood that the connecting part 22 can also extend out of the connecting cavity part 12, and the second convex part 32 is located in the high-pressure cavity part. Specifically, it can be determined according to the actual situation, and the embodiments of this specification do not limit this.

[0057] In some embodiments, it can also be as Figure 8 shown in partial view A, the cylindrical part 221 does not contact the second convex part 32 of the rotating shaft 3. Adopting this structure can indirectly make the rotating shaft 3, the impeller 1 and the connecting disc 2 concentric.

[0058] Of course, the mating form between the rotating shaft 3 and the connecting disk 2 is not limited to the above examples. Those skilled in the art may make other changes under the inspiration of the technical essence of the embodiments of this specification. However, as long as the functions and effects achieved are the same as or similar to those of the embodiments of this specification, they should all be covered within the protection scope of the embodiments of this specification.

[0059] In one embodiment, after installation, the mating surface of the connecting portion 22 is flush with the lower surface of the fixing portion 14, and the mating surface of the connecting portion 22, the lower surface of the fixing portion 14, and the mounting surface of the rotating shaft 3 are in contact; the mating surface of the connecting portion 22 is an end surface in contact with the mounting surface of the rotating shaft 3.

[0060] In this embodiment, as Figure 9 shown in the figure, after the connecting disk 2 and the impeller 1 are installed in place, the connecting disk 2 and the impeller 1 are aligned with the plane where the rotating shaft 3 is installed, and this combined plane cooperates with the upper assembly plane of the rotor to play a role in axial limit.

[0061] In this embodiment, the mating surface of the connecting portion 22 can be annular, and specifically can be determined according to the installation relationship with the rotor. The lower surface of the fixing portion 14 can be an end surface in contact with the mounting surface of the rotating shaft 3, or can be the end surface on the side close to the high-pressure cavity portion 13. After installation, the mating surface of the connecting portion 22, the lower surface of the fixing portion 14, and the mounting surface of the rotating shaft 3 can be aligned.

[0062] In one embodiment, the mating clearance between the first concave portion 31 and the first convex portion 222 or the mating clearance between the second concave portion 223 and the second convex portion 32 is 0 to 0.02 mm on one side.

[0063] In this embodiment, the small clearance fit between the concave portion and the convex portion plays a role in circumferential limit, and thus can improve the concentricity of the impeller and the rotor. The mating clearance can be set to 0 to 0.02 mm on one side, such as 0.008 mm, 0.01 mm, 0.012 mm, etc. Of course, it can be understood that the mating clearance can also be adjusted according to actual needs, and a larger one-sided clearance can be set, such as: 0.021 mm, 0.025 mm, 0.03 mm, etc. However, it should be noted that the larger the one-sided clearance, the corresponding lower the concentricity, and the vibration during operation may also increase. Specifically, it can be determined according to the actual test results, and this specification does not limit this.

[0064] In one embodiment, the fixing portion 14 is provided with a plurality of first fixing holes and a plurality of second fixing holes. Among them, the plurality of first fixing holes and the plurality of second fixing holes are blind holes; the balancing portion 21 and the fixing portion 14 are fixedly connected through a plurality of first locking members and the plurality of first fixing holes; the rotating shaft 3 and the fixing portion 14 are fixedly connected through a plurality of second locking members and the plurality of second fixing holes.

[0065] In this embodiment, the balance part 2 and the rotating shaft 3 can be fixed by opening a plurality of fixing holes in the fixing part 14. The first fixing hole and the second fixing hole can be of the same type of fixing hole or different types of fixing holes, and specifically can be determined according to the types of the first locking member and the second locking member. This embodiment of the specification does not make any limitation in this regard.

[0066] In this embodiment, a plurality of first fixing holes and a plurality of second fixing holes can be provided. The number of the first fixing holes corresponds to the number of the first locking members, and the number of the second fixing holes corresponds to the number of the second locking members. The number of the first fixing holes can be the same as or different from the number of the second fixing holes. The specific number can be 8, 6, 10, etc. Of course, in some embodiments, more or fewer fixing holes can also be provided, and specifically can be determined according to the actual situation. This embodiment of the specification does not make any limitation in this regard.

[0067] In this embodiment, in order to avoid gas leakage, the plurality of first fixing holes and the plurality of second fixing holes can be blind holes.

[0068] In this embodiment, the first locking member and the second locking member can be screws, nuts, bolts, etc., and specifically can be determined according to the actual situation. This embodiment of the specification does not make any limitation in this regard.

[0069] In one embodiment, at least one sealing member is provided at the contact positions of the fixing part 14 with the rotating shaft 3 and / or the connection disk 2 inside the plurality of first fixing holes and the plurality of second fixing holes.

[0070] In this embodiment, the installation position of the sealing member needs to avoid the fixing holes. Further considering that generally more fixing holes can be provided when the fixing holes are arranged on the outer side, so that the fixing effect will be better. Therefore, in order to ensure the installation space of the sealing member, the sealing member can be arranged inside the plurality of first fixing holes and the plurality of second fixing holes. Among them, the above-mentioned "inside" can be the contact position of the fixing part 14 with the rotating shaft 3, the side close to the axis of the rotating shaft 3 at the contact position of the fixing part 14 with the balance part 21, and the inner side wall of the connection cavity part.

[0071] In one embodiment, at least one sealing member can be provided on the lower surface 141 of the fixing part 14 inside the second fixing hole.

[0072] In this embodiment, if an interference fit is adopted between the connection disk 2 and the impeller 1, since hot fitting is required for the interference fit, setting the sealing member at the contact position between the impeller 1 and the connection disk 2 may cause the sealing member to deform or melt. Therefore, preferably, the sealing member can be set at a position not in contact with the connection disk.

[0073] In this embodiment, the lower surface 141 of the fixing part can be the surface that abuts against the rotating shaft 3, and this position will not be affected by the hot fitting of the connecting disc 2. Therefore, the sealing member can be arranged on the inner side of the second fixing hole on the lower surface 141 of the fixing part.

[0074] In this embodiment, as Figure 10 shown in the figure, the sealing member can be an O-ring. A sealing groove 4 can be arranged on the lower surface 141 of the fixing part, and the O-ring is arranged in the sealing groove 4. Of course, the sealing method is not limited to the above example. Those skilled in the art may make other changes under the inspiration of the technical essence of the embodiments of this specification. However, as long as the functions and effects achieved are the same as or similar to those of the embodiments of this specification, they should all be covered within the protection scope of the embodiments of this specification.

[0075] In one embodiment, at least one sealing groove 4 is provided at the contact position of the fixing part 14 with the rotating shaft and / or the connecting disc, and the sealing member is arranged in the sealing groove 4.

[0076] In this embodiment, the sealing groove 4 can be as Figure 10 shown in the figure. The shape of the sealing groove 4 can match the shape of the sealing member. The sealing groove 4 can be an annular structure. Of course, it can also be other possible shapes, such as: square, runway-shaped, etc. Specifically, it can be determined according to the actual situation, and this specification does not limit this.

[0077] In this embodiment, the number of the sealing grooves 4 can be set to be multiple, and correspondingly, multiple sealing members can be arranged. The specific number can be determined according to actual needs, and this specification does not limit this.

[0078] In one embodiment, the sealing member can include an O-ring seal.

[0079] In this embodiment, the sealing member can adopt a fluororubber O-ring for sealing, and the sealing compression rate of the O-ring is designed to be 23% - 25%. Of course, the type of the sealing member is not limited to the above example. Those skilled in the art may make other changes under the inspiration of the technical essence of the embodiments of this specification. However, as long as the functions and effects achieved are the same as or similar to those of the embodiments of this specification, they should all be covered within the protection scope of the embodiments of this specification.

[0080] It should be understood that the above description is for illustrative purposes and not for limitation. By reading the above description, many embodiments and many applications other than the provided examples will be obvious to those skilled in the art. Therefore, the scope of the embodiments of this specification should not be determined with reference to the above description, but should be determined with reference to the full scope of the foregoing claims and the equivalents of these claims.

[0081] The above are only the preferred embodiments of the embodiments of this specification and are not intended to limit the embodiments of this specification. For those skilled in the art, various modifications and changes can be made to the embodiments of this specification. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the embodiments of this specification shall be included within the protection scope of the embodiments of this specification.

Claims

1. A molecular pump, characterized in that: include: Impeller, adapter plate and shaft, wherein: The impeller has a through hole, the through hole includes a low-pressure cavity, a connecting cavity and a high-pressure cavity distributed along the axial direction, the inner diameter of the connecting cavity is smaller than the inner diameters of the high-pressure cavity and the low-pressure cavity, an annular fixing portion is formed between the low-pressure cavity and the high-pressure cavity, and at least one sealing member is provided at the contact between the impeller and the rotating shaft and / or the connecting disc; The adapter plate includes a balancing portion and a connecting portion, the adapter plate is an integrated structure, the balancing portion at least partially covers the low-pressure cavity, the balancing portion is fixedly connected to the fixing portion, the connecting portion extends into the connecting cavity, and the inner side wall of the connecting portion abuts against the inner side wall of the connecting cavity; The rotating shaft is arranged in the high-pressure chamber portion, and the rotating shaft is fixedly connected to the fixing portion.

2. The molecular pump according to claim 1, characterized in that: The impeller and the connecting plate are interference fitted.

3. The molecular pump according to claim 1 or 2, characterized in that: The connecting portion includes an axially distributed cylindrical portion and a first convex portion, an end surface of the rotating shaft close to the connecting cavity portion has a first concave portion matching the first convex portion, the cylindrical portion passes through the connecting cavity portion, and the first concave portion and the first convex portion are loosely matched to make the rotating shaft, the impeller and the connecting plate concentric; or, The connecting portion has a second recessed portion at one end close to the high-pressure chamber portion, and the rotating shaft has a second protruding portion matching the second recessed portion at one end face close to the connecting chamber portion, and the second recessed portion and the second protruding portion are loosely matched to make the rotating shaft, the impeller and the connecting plate concentric.

4. The molecular pump according to claim 3, characterized in that: After installation, the mating surface of the connecting part is flush with the lower surface of the fixing part, and the mating surface of the connecting part and the lower surface of the fixing part abut against the mounting surface of the rotating shaft; the mating surface of the connecting part is the end surface in contact with the mounting surface of the rotating shaft.

5. The molecular pump according to claim 4, characterized in that: The matching clearance between the first concave portion and the first convex portion or the matching clearance between the second concave portion and the second convex portion is 0 to 0.02 mm on one side.

6. The molecular pump according to claim 1 or 2, characterized in that: The fixing portion is provided with a plurality of first fixing holes and a plurality of second fixing holes, wherein the plurality of first fixing holes and the plurality of second fixing holes are blind holes; The balancing part and the fixing part are fixedly connected via a plurality of first locking members and a plurality of first fixing holes; The rotating shaft is fixedly connected to the fixing portion through a plurality of second locking members and a plurality of second fixing holes.

7. The molecular pump according to claim 6, characterized in that: The fixing portion is provided with at least one sealing member at the inner sides of the plurality of first fixing holes and the plurality of second fixing holes where the fixing portion contacts the rotating shaft and / or the connecting plate.

8. The molecular pump according to claim 6, characterized in that: At least one sealing member is provided on the lower surface of the fixing portion and located inside the second fixing hole.

9. The molecular pump according to claim 1, characterized in that: At least one sealing groove is provided at the contact point between the fixing portion and the rotating shaft and / or the connecting plate, and the sealing member is provided in the sealing groove.

10. The molecular pump according to claim 1, characterized in that: The sealing member comprises an O-ring.

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