Dry pump

Abstract

The utility model relates to the technical field of vacuum obtaining equipment, in particular to a dry pump. A dry pump includes: a housing assembly provided with an internal chamber and a side wall provided with an air inlet, the housing assembly including a low vacuum side housing; the composite impeller is arranged in the inner cavity, the composite impeller is provided with a turbine stage, and the turbine stage sucks gas entering from the gas inlet; the main shaft is arranged in the inner cavity and comprises a connecting section and a screw section, the peripheral wall of the connecting section is sleeved with the composite impeller, a first spiral groove is formed in the peripheral wall of the screw section, the periphery of the screw section is sleeved with the low-vacuum side shell, and an exhaust port is formed in the side wall, corresponding to the first spiral groove, of the low-vacuum side shell. The turbine stage sucks gas firstly, so that the gas is compressed in the first spiral groove, and the gas rotates along with the first spiral groove and is exhausted out of the exhaust port. The high vacuum pump solves the problem that when obtaining high vacuum, the high vacuum pump needs to be matched with other types of pumps to exhaust gas into the atmosphere.

Description

Technical Field

[0001] This utility model relates to the field of vacuum acquisition equipment technology, specifically to a dry pump. Background Technology

[0002] As a vacuum-generating device, the compound turbomolecular pump has a wide range of applications in the high vacuum industry. In some industries, such as semiconductors, the processing and manufacturing of products require a high vacuum environment.

[0003] Generally, to achieve high vacuum, high vacuum pumps are typically used, such as molecular pumps or diffusion pumps with cold traps. However, these high vacuum pumps must be used with a backing pump and cannot be directly vented to the atmosphere. Otherwise, accidents such as motor burnout, rotor blade breakage, and diffusion pump oil oxidation may occur. For example, the compound turbomolecular pump disclosed in CN116221151A can extract most of the air from a closed space, but it needs to be used in conjunction with other types of pumps to vent the gas to the atmosphere so that the space can reach the required ultimate vacuum environment. Utility Model Content

[0004] Therefore, the technical problem to be solved by this utility model is to overcome the defect that the high vacuum pump in the prior art needs to be used in conjunction with other types of pumps to discharge gas into the atmosphere when obtaining a high vacuum, thereby providing a dry pump.

[0005] To solve the above problems, this utility model provides a dry pump, comprising:

[0006] A housing assembly having an internal chamber and an air inlet on its side wall, the housing assembly including a low-vacuum side housing;

[0007] A compound impeller is disposed in the internal cavity, and the compound impeller is provided with a turbine stage, which draws in gas entering from the air inlet;

[0008] The main shaft is located within the internal cavity. The main shaft includes a connecting section and a screw section. The composite impeller is sleeved on the outer peripheral wall of the connecting section. The outer peripheral wall of the screw section is provided with a first helical groove. The low vacuum side housing is sleeved on the outer periphery of the screw section. The side wall of the low vacuum side housing corresponding to the first helical groove is provided with an exhaust port. In the working state, the main shaft rotates, and the turbine stage first draws in gas, which is then compressed in the first helical groove. The gas is discharged to the exhaust port as the first helical groove rotates.

[0009] Optionally, the housing assembly further includes a high-vacuum side housing and an inner sleeve. The high-vacuum side housing is sleeved on the outer periphery of the inner sleeve. The high-vacuum side housing is connected to the low-vacuum side housing. The low-vacuum side housing is fixedly connected to the inner sleeve. The composite impeller further includes a first traction section. The inner sleeve is sleeved on the outer periphery of the first traction section. The outer peripheral surface of the first traction section is provided with a second spiral groove.

[0010] Optionally, the low-vacuum side housing is provided with a second traction section, and the outer peripheral surface of the second traction section is provided with a third spiral groove, and the first traction section is sleeved on the outer periphery of the second traction section.

[0011] Optionally, a first gap is left between the end face of the first traction section away from the turbine stage and the end face of the low vacuum side housing, and a second gap is left between the end face of the second traction section of the low vacuum side housing and the inner end face of the first traction section.

[0012] Optionally, the helix angle of the second spiral groove is greater than that of the third spiral groove, the spiral groove depth of the second spiral groove is equal to that of the third spiral groove, and the spiral groove width of the second spiral groove is greater than that of the third spiral groove; the helix angle of the third spiral groove is greater than that of the first spiral groove, the spiral groove depth of the third spiral groove is equal to that of the first spiral groove, and the spiral groove width of the third spiral groove is greater than that of the first spiral groove.

[0013] Optionally, the helix angle of the second helical groove is greater than or equal to the helix angle of the third helical groove.

[0014] Optionally, the housing assembly further includes a high-vacuum side bearing housing and a low-vacuum side bearing cap, which are respectively located at both ends of the spindle.

[0015] Optionally, it also includes an airtight aero-mounted component and a power drive unit. The power drive unit is disposed between the low-vacuum side housing and the main shaft. The power drive unit includes a stator rotor and a moving rotor. The moving rotor is sleeved on the outer circumferential surface of the main shaft. The stator rotor is fixedly connected to the low-vacuum side housing. The airtight aero-mounted component is connected to the power drive unit via wiring.

[0016] Optionally, it also includes an air-cooling component, which is fixedly connected to the low-vacuum side bearing cap.

[0017] Optionally, the turbine stage includes a moving impeller and a stationary impeller, which are arranged sequentially at intervals.

[0018] The technical solution of this utility model has the following advantages:

[0019] 1. The dry pump provided by this utility model includes: a housing assembly having an internal chamber, an air inlet on the side wall of the housing assembly, and the housing assembly including a low-vacuum side housing; a compound impeller disposed in the internal chamber, the compound impeller having a turbine stage for absorbing gas entering from the air inlet; a main shaft disposed in the internal chamber, the main shaft including a screw section and a connecting end section, the compound impeller being sleeved on the outer peripheral wall of the connecting end section, a first helical groove being provided on the outer peripheral wall of the screw section, the low-vacuum side housing being sleeved on the outer periphery of the screw section, and an exhaust port being provided on the side wall of the low-vacuum side housing corresponding to the first helical groove.

[0020] In operation, the main shaft rotates, and the turbine stage first draws in gas, which is then compressed within the first helical groove. The gas is then discharged to the exhaust port as the first helical groove rotates. Through the arrangement of the turbine stage and the first helical groove, the rotation of the turbine stage directs the gas entering from the inlet, creating a suction effect. The gas is then compressed within the first helical groove and discharged to the exhaust port. It is important to note that when the screw section rotates, it acts as the rotor, and the low-vacuum side housing acts as the stator, achieving both suction and compression functions within the same pump body. Furthermore, both the compound impeller and the screw section rotate with the same main shaft. The turbine stage and screw section work together to achieve the function of direct gas discharge to the atmosphere.

[0021] 2. The dry pump provided by this utility model includes a high-vacuum side shell and an inner sleeve in the housing assembly. The high-vacuum side shell is fitted around the outer periphery of the inner sleeve. The high-vacuum side shell is connected to the low-vacuum side shell, and the low-vacuum side shell is fixedly connected to the inner sleeve. The compound impeller also includes a first traction section. The inner sleeve is located around the outer periphery of the first traction section, and the outer peripheral surface of the first traction section is provided with a second helical groove. This allows the first traction section to act as the rotor and the inner sleeve as the stator, so that the gas passes sequentially through the turbine stage, the second helical groove, and the first helical groove before being discharged to the exhaust port. Because the gas pumped by the turbine stage has a large pumping speed, the first traction section is designed to buffer the gas speed and better match the speed of the gas exiting the turbine stage, thereby reducing the speed of the gas entering the first helical groove.

[0022] 3. The dry pump provided by this utility model has a second traction section on the low vacuum side housing, and a third spiral groove on the outer circumferential surface of the second traction section. The first traction section is sleeved on the outer circumference of the second traction section. This allows the inner wall of the first traction section to act as the rotor and the second traction section as the stator, so that gas passes through the first traction section and then the second traction section before entering the first spiral groove. The second traction section further reduces the velocity of the gas entering from the first traction section.

[0023] 4. The dry pump provided by this utility model has a first gap between the end face of the first traction section away from the turbine stage and the end face of the low-vacuum side housing, and a second gap between the end face of the second traction section of the low-vacuum side housing and the inner end face of the first traction section. The first gap serves to connect the third helical groove and the first helical groove, and the second gap serves to connect the second helical groove and the first helical groove. Due to the arrangement of the first and second gaps, the screw section of the main shaft, the second traction section of the low-vacuum side housing, and the first traction section of the compound impeller can be arranged sequentially along the circumference of the main shaft, making the overall structure more compact, reducing the volume of the housing components, and improving the pumping effect.

[0024] 5. The dry pump provided by this utility model has a second spiral groove with a greater helix angle than the third spiral groove, a second spiral groove with a depth equal to the third spiral groove, and a second spiral groove with a width greater than the third spiral groove; the third spiral groove has a greater helix angle than the first spiral groove, a third spiral groove with a depth equal to the first spiral groove, and a third spiral groove with a width greater than the first spiral groove, so that the gas volume contained in the second spiral groove is greater than that in the third spiral groove, and the gas volume contained in the third spiral groove is greater than that in the first spiral groove.

[0025] 6. In the dry pump provided by this utility model, the helix angle of the second spiral groove is greater than or equal to the helix angle of the third spiral groove.

[0026] 7. The dry pump provided by this utility model further includes a high vacuum side bearing seat and a low vacuum side bearing cover in the housing assembly. The high vacuum side bearing seat and the low vacuum side bearing cover are respectively disposed at both ends of the main shaft to fix and seal the main shaft.

[0027] 8. The dry pump provided by this utility model further includes an airtight mounting component and a power drive component. The power drive component is located between the low-vacuum side housing and the main shaft. The power drive component includes a stator rotor and a moving rotor. The moving rotor is sleeved on the outer circumferential surface of the main shaft. The stator rotor is fixedly connected to the low-vacuum side housing. The airtight mounting component is electrically connected to the power drive component. The power drive component drives the main shaft to rotate. The airtight mounting component provides electrical energy, enabling the stator rotor and moving rotor to work together to convert electrical energy into kinetic energy, ultimately driving the main shaft to rotate.

[0028] 9. The dry pump provided by this utility model also includes an air-cooling component, which is fixedly connected to the low-vacuum side bearing cover, and the air-cooling component is used to cool the overall structure.

[0029] 10. The dry pump provided by this utility model has a turbine stage including a moving impeller and a stationary impeller. The outer circumferential surface of the moving impeller is arranged corresponding to the air inlet, and the moving impeller and the stationary impeller are arranged alternately in sequence. Attached Figure Description

[0030] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0031] Figure 1 This is a schematic diagram of the dry pump provided in an embodiment of the present invention;

[0032] Figure 2 This is a schematic diagram of the spindle provided in an embodiment of the present invention;

[0033] Figure 3 This is a schematic diagram of the main shaft and compound impeller provided in an embodiment of the present invention;

[0034] Figure 4 This is a cross-sectional view of the dry pump provided in the embodiment of this utility model;

[0035] Figure 5 for Figure 4 The diagram on the left;

[0036] Figure 6 for Figure 5 The diagram on the right;

[0037] Figure 7 This is a schematic diagram of the stationary impeller provided in an embodiment of the present invention;

[0038] Figure 8 This is a schematic diagram of the low-vacuum side housing provided in an embodiment of the present invention;

[0039] Figure 9 This is a schematic diagram of the high-vacuum side housing provided in an embodiment of the present invention.

[0040] Explanation of reference numerals in the attached drawings: 1. Main shaft; 2. Moving rotor; 3. Low vacuum side housing; 4. Low vacuum side bushing; 5. Stator rotor; 6. Bearing; 7. Locking block; 8. Low vacuum side bearing seat; 9. Elastic element; 10. Low vacuum side bearing cover; 11. Inner sleeve; 12. Exhaust port; 13. Composite impeller; 14. Locking element; 15. Stationary impeller; 16. High vacuum side housing; 17. High vacuum side bearing seat; 18. High vacuum side bearing cover; 19. High vacuum side bushing; 20. First connecting flange; 21. Airtight fitting; 22. Air-cooled assembly; 23. Screw section; 24. First spiral groove; 25. Second gap; 26. First traction section; 27. Second traction section; 28. First gap; 29. ​​Air inlet; 30. Moving impeller; 31. Support end. Detailed Implementation

[0041] The technical solution of this utility model will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0042] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0043] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0044] Furthermore, the technical features involved in the different embodiments of this utility model described below can be combined with each other as long as they do not conflict with each other.

[0045] like Figure 1 One embodiment of the dry pump shown in Figure 9 includes: a housing assembly having an internal chamber, and a main shaft 1 and a compound impeller 13 disposed within the housing assembly.

[0046] like Figure 1 , Figure 2 As shown, the main shaft 1 includes a connecting section and a screw section 23, wherein the screw section 23 is provided with a spiral first spiral groove 24.

[0047] like Figure 1 , Figure 3 , Figure 5 and Figure 7As shown, the compound impeller 13 includes a turbine stage and a first traction section 26. The turbine stage of the compound impeller 13 is sleeved on the outer periphery of the connecting section of the main shaft 1. The compound impeller 13 is fixedly connected to the main shaft 1 by a locking member 14. The turbine stage has five moving impellers 30 and five stationary impellers 15 arranged alternately, that is, the arrangement sequence of the moving impellers 30 and stationary impellers 15 is "1 moving impeller 30 - 1 stationary impeller 15 - 1 moving impeller 30 - 1 stationary impeller 15...". The outer peripheral surface of the first traction section 26 is provided with a second spiral groove. It should be noted that each stage of moving impeller 30 and each stage of stationary impeller 15 contains several blades. The blades of the moving impeller 30 and the blades of the stationary impeller 15 have opposite inclination angles. The pressure surface and suction surface of each blade are curved surfaces. The blade thickness gradually decreases from the root to the top, and the blade angle also gradually decreases. It should be noted that the number of blades on the impeller 30 closest to the first traction section 26 is greater. That is, the impeller 30 closest to the first traction section 26 has the most blades, and the impeller 30 furthest from the first traction section 26 has the fewest blades. The number of blades between the two is progressive. At the same time, the more blades there are, the smaller the blade width is. That is, the impeller 30 closest to the first traction section 26 has the smallest blade width, and the impeller 30 furthest from the first traction section 26 has the largest blade width.

[0048] like Figure 1 , Figure 4 , Figure 5 , Figure 6 , Figure 8 and Figure 9 The housing assembly includes a high-vacuum side housing 16, a low-vacuum side housing 3, and an inner sleeve 11. The high-vacuum side housing 16 and the low-vacuum side housing 3 are fixedly connected. The low-vacuum side housing 3 is fitted around the outer periphery of the screw section 23 of the main shaft 1. The low-vacuum side housing 3 has a second traction section 27, and the outer peripheral surface of the second traction section 27 has a third helical groove. The inner sleeve 11 is fitted around the outer periphery of the first traction section 26 of the composite impeller 13. The high-vacuum side housing 16 is fitted around the outer periphery of the inner sleeve 11. The low-vacuum side housing 3 and the inner sleeve 11 are fixedly connected, thereby forming... Figure 1As shown, the screw section 23 of the autonomous shaft 1 is arranged circumferentially outwards as follows: the second traction section 27 of the low-vacuum side housing 3 and the first traction section 26 of the compound impeller 13. It should be noted that for the high-vacuum (HV) side housing and the low-vacuum (LV) side housing, the helix angle of the second helical groove is greater than that of the third helical groove, and the depth and width of the second helical groove are greater than those of the third helical groove. To connect the first traction section 26 and the second traction section 27, a first gap 28 is left between the end face of the first traction section 26 facing away from the turbine stage and the end face of the low-vacuum side housing 3, serving to connect the third and second helical grooves; to connect the second traction section 27 and the screw section 23, a second gap 25 is left between the end face of the second traction section 27 of the low-vacuum side housing 3 and the inner end face of the first traction section 26, serving to connect the third helical groove and the first helical groove 24. Figure 1 As shown, the high-vacuum side housing 16 is provided with a first connecting flange 20, which has an air inlet 29. The low-vacuum side housing 3 is provided with a second connecting flange, which has an exhaust port 12. The end of the screw section 23 facing away from the connecting section is correspondingly positioned to the exhaust port 12. With the above arrangement, when the main shaft 1 rotates, the impeller 30 rotates and draws in the gas entering from the air inlet 29. The gas then passes sequentially through "turbine stage → second spiral groove of first traction section 26 → second gap 25 → third spiral groove of second traction section 27 → first gap 28 → first spiral groove 24 of screw section 23", and finally exits through screw section 23 to exhaust port 12. The spiral helix angle, spiral groove depth, and spiral groove width are equal at the beginning and end of the second spiral groove in the first traction section 26; the spiral helix angle, spiral groove depth, and spiral groove width are equal at the beginning and end of the third spiral groove in the second traction section 27; the spiral helix angle, spiral groove depth, and spiral groove width of the first spiral groove in the screw section 23 gradually decrease from the beginning to the end of the section, and the spiral helix angle, spiral groove depth, and spiral groove width of the second spiral groove are greater than those of the third spiral groove, the spiral helix angle, spiral groove depth, and spiral groove width of the third spiral groove are greater than those of the first spiral groove 24, and the starting angle of the same first spiral groove 24 is greater than the ending angle.

[0049] To enclose the internal cavity within the housing assembly, the housing assembly also includes a high-vacuum side bearing housing 17, which is fixedly connected to the high-vacuum side housing 16. For example... Figure 1As shown, the high-vacuum side bearing housing 17 and the main shaft 1, and the support end 31 of the low-vacuum side housing 3 and the main shaft 1 respectively form a spiral seal. This also allows the main shaft 1 to form a simply supported beam structure, achieving a seal through spiral action, ensuring that gas does not enter the internal cavity when the main shaft 1 is rotating. The simply supported beam structure facilitates individual stress on adjacent spans, reduces the impact of displacement, and improves manufacturing and installation convenience. To further connect the main shaft 1, a bearing 6, a high-vacuum side bushing 19, an elastic element 9, and a high-vacuum side bearing cap 18 are provided between the high-vacuum side bearing housing 17 and the main shaft 1. The bearing 6 is sleeved on the outer circumferential surface of the main shaft 1, and the high-vacuum side bushing 19 is sleeved on the outer circumferential surface of the bearing 6. The high-vacuum side bearing cap 18 is fixedly connected to the main shaft 1 by a locking block 7. The elastic element 9 is located between the high-vacuum side bearing cap 18 and the high-vacuum side bushing 19. Specifically, the elastic element 9 is a wave spring.

[0050] To drive spindle 1 to rotate, such as Figure 1 As shown, it also includes an airtight aero-mounted insert 21 and a power drive component. The power drive component is located between the low-vacuum side housing 3 and the main shaft 1. The power drive component includes a stator rotor 5 and a moving rotor 2. The moving rotor 2 is sleeved on the outer circumferential surface of the main shaft 1. The stator rotor 5 is fixedly connected to the low-vacuum side housing 3. The airtight aero-mounted insert 21 is located outside the main shaft 1 and is wired to the power drive component. The airtight aero-mounted insert 21 provides electrical energy to drive the moving rotor 2 to rotate. To further connect the main shaft 1, a low-vacuum side bearing cap 10 is provided at the end of the main shaft 1 near the air-cooling assembly 22. A bearing 6 and a low-vacuum side bushing 4 are provided between the low-vacuum side bearing cap 10 and the main shaft 1. The bearing 6 and the low-vacuum side bushing 4 are assembled by heat fitting. The bearing 6 is sleeved on the outer circumferential surface of the main shaft 1 and positioned by a shoulder. The outer side of the low-vacuum side bushing 4 is assembled with the low-vacuum side bearing seat 8, and the low-vacuum side bushing 4 is axially locked to the bearing by a locking block 7. Figure 1 As shown, it also includes a low-vacuum side bearing housing 8, and the low-vacuum side housing 3 and the low-vacuum side bearing housing 8 are fixed together by screws. The low-vacuum side bearing housing 8 is fixedly connected to the low-vacuum side bearing cap 10. To cool the overall structure, it also includes an air-cooling assembly 22, which is fixedly connected to the low-vacuum side housing.

[0051] A method for installing a dry pump includes the following steps:

[0052] 1) The main shaft 1 and the moving rotor 2 are assembled by heat fitting. Glue is applied to the glue groove. The main shaft 1 and the composite impeller 13 are assembled by heat fitting in two places and locked by locking parts 14. The moving rotor 2 is dynamically balanced after completion to meet the design requirements.

[0053] 2) The low vacuum side housing 3 and the inner sleeve 11 are heat-fitted. The sealing ring of the low vacuum side housing 3 is assembled before heat-fitting. The stator and rotor 5 are assembled with the low vacuum side housing 3 by press fitting. The front end of the stator and rotor 5 is attached with a thermally conductive silicone pad. After assembly, the stator and rotor 5 is fixed by set screws. Finally, it is sealed. Then, the low vacuum side bearing seat 8 is assembled with the low vacuum side housing 3. The low vacuum side housing 3 and the low vacuum side bearing cover 10 are connected by screws. The connection is sealed with fluororubber O-rings.

[0054] 3) Heat-fit the bearing 6 to the low vacuum side bushing 4, and then assemble the bearing 6 and the main shaft 1 by press fitting. The low vacuum side bushing 4 is equipped with an O-ring for damping. After the bearing 6 and the main shaft 1 are installed, they are fixed by locking block 7 and M6 screw. Finally, install the low vacuum side bearing cover 10.

[0055] 4) Turn the tooling over to stand up the previously assembled parts, and then install the stationary blades one by one. The relevant dimensions must be measured after each stage is installed.

[0056] 5) Assemble the high vacuum side housing 16 with the assembled parts, wherein the axial direction is positioned by the stationary impeller 15, the radial direction is positioned by the outer ring of the low vacuum side housing 3, and finally the parts are locked by M5 screws.

[0057] 6) Assemble the high vacuum side bearing housing 17 with the high vacuum side housing 16, and lock them together with screws. Seal the contact surfaces with O-rings.

[0058] 7) Heat-fit the bearing 6 to the high vacuum side bushing 19, and then press-fit it to the main shaft 1. The high vacuum side bearing housing 17 and the high vacuum side bearing cover 18 have O rings on the contact surface to provide damping.

[0059] 8) After placing the elastic element 9 in the bearing 6 cavity, press it onto the outer ring of the elastic element 9 by the high vacuum side bearing cover 18, and finally fix it with screws;

[0060] 9) Install accessories such as the first connecting flange 20, airtight air plug 21, purging assembly, gas filter assembly, silencer, plug, vent valve and other external accessories, and install the external sheet metal parts and electrical control module of the air-cooled assembly 22.

[0061] A method of using a dry pump involves the impeller 30 rotating to draw in gas entering through the inlet 29 when the main shaft 1 rotates. The gas then passes sequentially through the turbine stage, first traction section 26, second gap 25, second traction section 27, first gap 28, and screw section 23, finally exiting through the screw section 23 to the exhaust port 12. Initially, the high-speed rotation of the turbine stage transfers momentum to the gas molecules at the inlet 29, causing them to move on the turbine blade surface and flow in a directional direction towards the first traction section 26, thus achieving the purpose of pumping air. Upon entering the first traction section 26, the gas enters a viscous flow state due to the action of the second helical groove. Through the combined action of the first traction section 26, the second traction section 27, and the screw section 23, the gas is pressurized stage by stage until it reaches the exhaust port 12 for discharge.

[0062] As an alternative implementation, the helix angle of the second helical groove is equal to the helix angle of the third helical groove.

[0063] As an alternative implementation, the helix angle, helix depth, and helix width of the second helix groove can also be equal to those of the third helix groove.

[0064] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the protection scope of this invention.

Claims

1. A dry pump, characterized by, The utility model relates to a kind of vacuum pump, including: Shell assembly, the shell assembly is equipped with internal chamber, the side wall of the shell assembly is equipped with air inlet (29), the shell assembly includes low vacuum side shell (3); Composite impeller (13) is located in the internal chamber, the composite impeller (13) is equipped with turbine stage, the turbine stage is inhaled gas entering from air inlet (29); Main shaft (1) is located in the internal chamber, the main shaft (1) includes connecting section and screw section (23), the composite impeller (13) is sleeved on the outer circumferential wall of connecting section, the outer circumferential wall of screw section (23) is equipped with first helical groove (24), the low vacuum side shell (3) is sleeved on the outer circumferential of screw section (23), the side wall of the low vacuum side shell (3) is equipped with exhaust port (12) corresponding first helical groove (24), in working condition, main shaft (1) rotates, the turbine stage first inhales gas, so that gas is compressed in first helical groove (24) again, gas is discharged to exhaust port (12) outside with the rotation of first helical groove (24).

2. The dry pump according to claim 1, characterized in that, The shell assembly further includes high vacuum side shell (16) and inner sleeve (11), the high vacuum side shell (16) is sleeved on the outer circumferential of inner sleeve (11), the high vacuum side shell (16) is connected with low vacuum side shell (3), the low vacuum side shell (3) is fixedly connected with inner sleeve (11), the composite impeller (13) further includes first traction section (26), the inner sleeve (11) is sleeved on the outer circumferential of first traction section (26), the outer circumferential surface of first traction section (26) is equipped with second helical groove.

3. The dry pump according to claim 2, characterized in that, The low vacuum side shell (3) is equipped with second traction section (27), the outer circumferential surface of second traction section (27) is equipped with third helical groove, and the first traction section (26) is sleeved on the outer circumferential of second traction section (27).

4. The dry pump according to claim 3, characterized in that, The end surface of the first traction section (26) away from the turbine stage and the end surface of the low vacuum side shell (3) leave first gap (28), and the end surface of the second traction section (27) of the low vacuum side shell (3) and the inner end surface of the first traction section (26) leave second gap (25).

5. The dry pump according to claim 3, characterized in that, The helix angle of the second helical groove is greater than the helix angle of the third helical groove, the helical groove depth of the second helical groove is equal to the helical groove depth of the third helical groove, and the helical groove width of the second helical groove is greater than the helical groove width of the third helical groove.

6. The dry pump according to claim 5, characterized in that, The helix angle of the second helical groove is greater than or equal to the helix angle of the third helical groove.

7. The dry pump according to claim 4, characterized in that, The shell assembly further includes high vacuum side bearing seat (17) and low vacuum side bearing gland (10), and the high vacuum side bearing seat (17) and the low vacuum side bearing gland (10) are separately arranged at both ends of the main shaft (1).

8. The dry pump according to claim 7, characterized in that The air-tight navigation plug (21) is connected with the power driving element in circuit.

9. Dry pump according to claim 8, characterized in that The air-cooling assembly (22) is fixedly connected with the low-vacuum side bearing gland (10).

10. The dry pump according to claim 1, characterized in that, The turbine stage comprises a moving blade wheel (30) and a static blade wheel (15), and the moving blade wheel (30) and the static blade wheel (15) are arranged in sequence and at intervals.

Images