Multi-shaft mixing pump

Abstract

The utility model discloses a multi-shaft mixing pump which comprises a pump body provided with a screw pump body cavity and a roots pump body cavity, at least two parallel connecting shafts are installed in the pump body in a rotating mode, and the two sides of the middles of the two connecting shafts are arranged in the screw pump body cavity and the roots pump body cavity respectively. A screw rotor part and a roots rotor part are respectively mounted on the connecting shaft in the screw pump body cavity and the roots pump body cavity, and the screw pump is characterized in that two ends of the connecting shaft are respectively and rotatably connected with the pump body, and two via holes for communicating the roots pump body cavity with the screw pump body cavity are formed in the pump body; the middle parts of the two connecting shafts are respectively inserted into the two via holes; one end of the connecting shaft is rotationally connected with the pump body at one end of the roots pump body cavity through a bearing; the end, located in the screw pump body cavity, of the connecting shaft is rotationally connected with the pump body at one end of the screw pump body cavity through a bearing. According to the utility model, the maintenance rate is reduced, and the service life is prolonged.

Description

Technical Field

[0001] The utility model relates to a vacuum pump, in particular to a multi-axis mixing pump. Background Art

[0002] There are many types of vacuum pumps, and different vacuum pumps are used in different industries. For example, Roots vacuum pumps and screw vacuum pumps can be used alone or in combination. When used in combination, in the conventional way, such as application number: 2024107239229, patent name: an integrated vacuum system, application number: 2024107237967, patent name: a two-axis hybrid pump, application number: 202410723744X, patent name: a three-axis hybrid pump, it adopts a structure of a combination of Roots pump and screw pump, but this structure, the screw pump adopts a cantilever screw structure, the shaft at the end of the Roots pump is supported by bearings, the shaft between the Roots pump body cavity and the screw pump body cavity is also supported by bearings, and the end of the shaft in the screw pump body cavity is a cantilever structure (its end is suspended and does not need support). In actual use, there are the following shortcomings:

[0003] The coupling shaft at the pump body between the Roots pump body cavity and the screw pump body cavity adopts double-row bearings for rotation support, and the coupling shaft end at the Roots pump adopts single-row bearings for support. The double-row bearings play the role of supporting the coupling shaft and limiting the axial position, and the single-row support plays the role of supporting the coupling shaft. The combination of double-row bearings and single-row bearings can realize the limiting of the coupling shaft, which is also convenient for installation and debugging. However, the coupling shaft at the screw rotor component adopts a cantilever mechanism, and the installation space of the double-row bearings is limited. The double-row bearing setting will be relatively small. Moreover, since it is in the middle position of the pump body, it is not convenient to set up oil cavity lubrication, and only grease can be used to lubricate the double-row bearings. The pump body between the Roots pump body cavity and the screw pump body cavity is in the process of using the vacuum pump, and the temperature will be particularly high, and the grease is not resistant to high temperature. If the vacuum pump is used for less than 1 month (theoretically, due to the poor use environment of the vacuum pump, the service life should be about 3-6 months), the double-row bearing will be damaged, resulting in a high maintenance rate and a short service life. Summary of the invention

[0004] The utility model aims to provide a multi-axis mixing pump, which can effectively reduce the maintenance rate and prolong the service life by using the structure.

[0005] In order to achieve the above-mentioned object, the technical solution adopted by the utility model is: a multi-axis mixing pump, comprising a pump body having a screw pump body cavity and a Roots pump body cavity, at least two mutually parallel connecting shafts are rotatably installed in the pump body, the middle two sides of the two connecting shafts are respectively arranged in the screw pump body cavity and the Roots pump body cavity, and the screw rotor component and the Roots rotor component are respectively installed on the connecting shafts in the screw pump body cavity and the Roots pump body cavity.

[0006] The two ends of the connecting shaft are rotatably connected to the pump body respectively, and the pump body is provided with two through holes for connecting the Roots pump body cavity with the screw pump body cavity, and the middle parts of the two connecting shafts are respectively inserted into the two through holes;

[0007] One end of the connecting shaft is rotatably connected to the pump body at one end of the Roots pump body cavity via a bearing;

[0008] The end of the connecting shaft located in the screw pump body cavity is rotatably connected to the pump body at one end of the screw pump body cavity via a bearing.

[0009] In the above technical solution, there is a micro gap between the outer surface of the coupling shaft and the inner wall of the through hole;

[0010] And / or, one end of the coupling shaft is rotatably connected to the pump body at one end of the Roots pump body cavity via a double-row bearing;

[0011] The end of the coupling shaft located in the screw pump body cavity is rotatably connected to the pump body at one end of the screw pump body cavity via a single-row bearing.

[0012] In the above technical solution, a first oil chamber is further provided in the pump body, the screw pump body chamber is arranged between the first oil chamber and the Roots pump body chamber, and the outer end of the bearing on the screw pump body chamber side is arranged in the first oil chamber.

[0013] In the above technical solution, a second oil chamber is further provided in the pump body, the Roots pump body chamber is arranged between the second oil chamber and the screw pump body chamber, and the outer end of the bearing on the Roots pump body chamber side is arranged in the second oil chamber.

[0014] In the above technical solution, an oil seal is respectively provided on the connecting shaft inside each of the bearings.

[0015] In the above technical solution, the oil seal includes a first annular body and a second annular body, the first annular body is sleeved on the connecting shaft, the outer surface of the first annular body abuts against the inner wall of the pump body, and the inner surface of the first annular body abuts against the outer surface of the connecting shaft;

[0016] An annular cavity is provided in the middle of the inner surface of the first annular body, the second annular body is arranged in the annular cavity, one end of the second annular body is connected to the inner wall of the annular cavity, and the inner surface of the other end of the second annular body abuts against the outer surface of the connecting shaft.

[0017] In the above technical solution, a through hole is provided on the outer surface of the first annular body and communicated with the annular cavity, the through hole is arranged opposite to the second annular body, and a nitrogen connection hole communicated with the through hole is provided on the outer wall of the pump body.

[0018] In the above technical solution, there are two screw rotor components, and the two screw rotor components are respectively installed on one connecting shaft, and the two screw rotor components are meshed with each other;

[0019] The screw rotor component is sleeved on the outside of the connecting shaft, and the screw rotor component is circumferentially limited on the connecting shaft through splines;

[0020] An axial limiter is also installed on the connecting shaft at both ends of the screw rotor component.

[0021] In the above technical solution, the axial limit member includes a limit ring, the side wall of the limit ring abuts against the end surface of the screw rotor component, and a sealing ring is further provided at the contact point between the limit ring and the screw rotor component.

[0022] In the above technical solution, there are two connecting shafts, the middle part of which is arranged in the pump body between the Roots pump body cavity and the screw pump body cavity, and the two ends of the connecting shaft respectively penetrate into the Roots pump body cavity and the screw pump body cavity and are rotatably connected to the pump body;

[0023] Alternatively, there are three connecting shafts, the middle parts of two of the connecting shafts are arranged in the pump body between the Roots pump body cavity and the screw pump body cavity, and the two ends of the two connecting shafts respectively penetrate into the Roots pump body cavity and the screw pump body cavity and are rotatably connected to the pump body; another connecting shaft is arranged in the Roots pump body cavity, and the two ends of the connecting shaft are rotatably connected to the pump body at both ends of the Roots pump body cavity.

[0024] Due to the application of the above technical solution, the utility model has the following advantages compared with the prior art:

[0025] 1. The two ends of the connecting shaft that penetrate into the Roots pump body cavity and the screw pump body cavity in the utility model are directly connected to the pump body for rotation through bearings. It adopts a fixed structure at both ends. Compared with the previous cantilever screw structure, the service life of the bearing is longer and the maintenance rate can be effectively reduced;

[0026] 2. In the utility model, a first oil chamber is arranged in the pump body to cool the single-row bearing. Compared with the previous structure using grease cooling, the cooling effect of the bearing is better, the service life is longer, and the maintenance rate is lower;

[0027] 3. In the utility model, an oil seal is also arranged beside the corresponding bearing, a first annular body and a second annular body are arranged on the oil seal, one end of the second annular body is connected to the first annular body, and nitrogen is introduced into the oil seal, and the second annular body is pushed by the nitrogen to always press against the outer surface of the connecting shaft, so as to stably play the role of the oil seal, prevent objects from entering the corresponding oil cavity to contaminate the lubricating oil, and also prevent the lubricating oil from entering the corresponding pump body cavity. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of the structure of the first embodiment of the present utility model;

[0029] Figure 2 yes Figure 1 A partial enlarged view of the middle oil seal;

[0030] Figure 3 It is a structural schematic diagram of the second embodiment of the present utility model.

[0031] Among them: 1. Screw pump body cavity; 2. Roots pump body cavity; 3. Pump body; 4. Coupling; 5. Screw rotor component; 6. Through hole; 7. Double-row bearing; 8. Single-row bearing; 9. Partition; 10. First-stage Roots pump body cavity; 11. Second-stage Roots pump body cavity; 12. First-stage Roots rotor component; 13. Second-stage Roots rotor component; 14. Gear; 15. Motor; 16. First oil chamber; 17. Second oil chamber; 18. Oil seal; 19. First annular body; 20. Second annular body; 21. Annular cavity; 22. Through hole; 23. Nitrogen connecting hole; 24. Annular sealing lip; 25. Axial limiter; 26. Limiting ring; 27. Sealing ring; 30. Intermediate coupling; 31. First coupling; 32. Second coupling. DETAILED DESCRIPTION

[0032] The utility model is further described below in conjunction with the accompanying drawings and embodiments:

[0033] Example 1: See Figure 1 , 2As shown, a multi-axis mixing pump comprises a pump body 3 having a screw pump body cavity 1 and a Roots pump body cavity 2, wherein two parallel connecting shafts 4 are rotatably installed in the pump body 3, the middle parts of the two connecting shafts 4 are respectively arranged in the screw pump body cavity 1 and the Roots pump body cavity 2, the middle part of the connecting shaft 4 is arranged in the pump body 3 between the Roots pump body cavity 2 and the screw pump body cavity 1, and the two ends of the connecting shaft 4 respectively penetrate the Roots pump body cavity 2 and the screw pump body cavity 1 and are rotatably connected to the pump body 3; the screw rotor component 5 and the Roots rotor component are respectively installed on the connecting shaft 4 in the screw pump body cavity 1 and the Roots pump body cavity 2,

[0034] The two ends of the connecting shaft 4 are rotatably connected to the pump body 3 respectively. The pump body 3 is provided with two through holes 6 for connecting the Roots pump body cavity 2 with the screw pump body cavity 1. The middle parts of the two connecting shafts 4 are respectively inserted into the two through holes 6.

[0035] One end of the connecting shaft 4 is rotatably connected to the pump body 3 at one end of the Roots pump body cavity 2 via a double-row bearing 7;

[0036] The end of the connecting shaft 4 located in the screw pump body cavity 1 is rotatably connected to the pump body 3 at one end of the screw pump body cavity 1 via a single-row bearing 8.

[0037] In this embodiment, taking the direction shown in the figure as an example, the Roots pump body cavity is set on the left side of the screw pump body cavity, and the two through holes are used to connect the Roots pump body cavity and the screw pump body cavity, which are used to make way for the connecting shaft, so that the two sides of the connecting shaft can be respectively in the Roots pump body cavity and the screw pump body cavity. Furthermore, there is a micro gap between the outer surface of the connecting shaft and the inner wall of the through hole, so that the connecting shaft in the through hole will not contact the pump body, and will not rub against the rigidity of the pump body during the rotation of the connecting shaft, thereby preventing damage to the pump body and the connecting shaft. Among them, the micro gap is relatively small, and even if the gas in the Roots pump body cavity enters the screw pump body cavity from the micro gap, it will not affect the normal vacuuming action.

[0038] Among them, in this embodiment, there are two screw rotor components 5, and the two screw rotor components are respectively installed on one of the connecting shafts. The two screw rotor components mesh with each other, and the outer surface of the screw rotor component has a spiral groove (spiral exhaust groove), and the groove width of the spiral groove gradually decreases from left to right. The screw rotor component beside the spiral groove will mesh with the spiral groove of the adjacent screw rotor component (and there is a gap between the two and they will not contact each other). A partition 9 is provided in the middle of the Roots pump body cavity, which divides the Roots pump body cavity into a primary Roots pump body cavity 10 and a secondary Roots pump body cavity 11. The secondary Roots pump body cavity is arranged between the primary Roots pump body cavity and the screw pump body cavity, and the partition also has a hole position for making way for the connecting shaft. A Roots rotor component is arranged on each coupling shaft, and the two Roots rotor components are meshed. A notch is arranged on each Roots rotor component, and the notch separates the Roots rotor components into a primary Roots rotor component 12 and a secondary Roots rotor component 13. The primary Roots rotor component is arranged in the primary Roots pump body cavity, and the secondary Roots rotor component is arranged in the secondary Roots pump body cavity. An air inlet and an exhaust port are arranged on the pump body, which are respectively connected to the primary Roots pump body cavity and the screw pump body cavity. The air inlet connects the top of the primary Roots pump body cavity with the top outer wall of the pump body. A first connecting channel is arranged in the pump body, one end of the first connecting channel is connected to the bottom of the primary Roots pump body cavity, and the other end is connected to the top of the secondary Roots pump body cavity. A second connecting channel is also arranged in the pump body, and the two ends of the second connecting channel are respectively connected to the bottom of the secondary Roots pump body cavity and the left end of the screw pump body cavity, and the exhaust port connects the right end of the screw pump body cavity and the outer wall of the pump body. The left ends of the two connecting shafts are respectively provided with gears 14 that mesh with each other. The left side of the pump body is provided with a motor 15 connected to the left end of a connecting shaft. When the motor drives one connecting shaft to rotate, it will drive the other connecting shaft to rotate through the gear. During the rotation of the connecting shaft, it will synchronously drive the meshing Roots rotor components and the screw rotor components to rotate synchronously, thereby realizing the negative pressure vacuum pumping action. In this process, the meshing first-stage Roots rotor components suck the gas outside the pump body from the air inlet into the first-stage Roots pump body cavity above the first-stage Roots rotor components, and then send the gas into the first-stage Roots pump body cavity below the first-stage Roots rotor components, and then send it to the top of the second-stage Roots pump body cavity through the first connecting channel (the first-stage Roots rotor components and the second-stage Roots rotor components on the same connecting shaft have the same rotation direction), and then send the gas into the second-stage Roots pump body cavity below the second-stage Roots rotor components through the second-stage Roots rotor components, send it into the screw pump body cavity through the second connecting channel, and discharge the gas from the exhaust port through the screw rotor components, thereby realizing the negative pressure vacuuming action. Its working principle is basically the same as the working principle in Application No.: 2024107239229, Patent Name: An Integrated Vacuum System, Application No.: 2024107237967, Patent Name: A Two-axis Mixing Pump.

[0039] Among them, in this embodiment, the coupling shaft in the screw pump body cavity is a non-cantilever screw, and the two ends of the coupling shaft are supported and limited by single-row bearings and double-row bearings respectively. Among them, the double-row bearings can support and axially limit the bearings to prevent the axial movement of the coupling shaft, and the single-row bearings can support the bearings. In this way, during the assembly process, one end of the coupling shaft is first installed after the double-row bearing or the single-row bearing is installed, and then assembled. This facilitates adjustment during the assembly process and adjusts the assembly clearance of the corresponding Roots rotor components and the screw rotor components.

[0040] At the same time, in this embodiment, the coupling is a non-cantilever screw structure, so that during the rotation of the screw rotor components, micro-deformation of the coupling end can be prevented, which would cause the screw rotor components to rub and collide with each other, thereby effectively extending the service life and reducing the maintenance rate.

[0041] Furthermore, the single-row bearing is arranged at the end of the connecting shaft, and the high temperature environment of the Roots pump body cavity and the screw pump body cavity will not affect the single-row bearing. Even if conventional grease lubrication is used, it will not affect its normal use, effectively extending the service life of the single-row bearing and reducing the maintenance rate.

[0042] Furthermore, a first oil chamber 16 is further provided in the pump body 3 , the screw pump body chamber 1 is provided between the first oil chamber 16 and the Roots pump body chamber 2 , and the outer end of the single-row bearing 8 is provided in the first oil chamber 16 .

[0043] The first oil chamber is set up with high-temperature resistant lubricating oil in the first oil chamber, so that the lubricating oil in the first oil chamber can be used to lubricate the single-row bearing. The lubricating oil is a high-temperature resistant lubricating oil, which can effectively ensure the normal lubrication and use of the single-row bearing, ensure the service life of the single-row bearing, and reduce the maintenance rate.

[0044] The pump body 3 is further provided with a second oil chamber 17 , the Roots pump body chamber is arranged between the second oil chamber 17 and the screw pump body chamber 1 , and the outer end of the double row bearing 7 is arranged in the second oil chamber 17 .

[0045] Similarly, by setting up a second oil chamber and setting high-temperature resistant lubricating oil in the second oil chamber, the lubricating oil in the second oil chamber can be used to lubricate the double-row bearings, which can effectively ensure the normal lubrication and use of the double-row bearings, ensure the service life of the double-row bearings, and reduce the maintenance rate.

[0046] In this embodiment, the first oil chamber is arranged at the right end of the pump body, and the second oil chamber is arranged at the left end of the pump body, which will not occupy the space of the Roots pump body cavity and the screw pump body cavity. In this way, a cooling channel can be arranged outside the first oil chamber and the second oil chamber to cool the lubricating oil in the first oil chamber and the second oil chamber, which can not only ensure the normal lubrication of the bearing, but also cool it down, so that the bearing can operate at the optimal operating temperature as much as possible, ensuring the service life and stability of use.

[0047] See also Figure 1 As shown, an oil seal 18 is respectively provided on the connecting shaft 4 on the inner side of the double-row bearing 7 and on the connecting shaft 4 on the inner side of the single-row bearing 8.

[0048] In this embodiment, an oil seal is arranged on the coupling shaft on the right side of the double-row bearing on the left side, and an oil seal is also arranged on the coupling shaft on the left side of the single-row bearing on the right side. The two oil seals are arranged between the two bearings respectively and are arranged close to the bearings on the corresponding sides, so that the lubricating oil in the oil chamber on the corresponding side can be prevented from entering the Roots pump body cavity and the screw pump body cavity from the gap between the bearing and the coupling shaft, and the gap between the bearing and the pump body, thereby ensuring the normal operation of the Roots rotor component and the screw rotor component. At the same time, the vacuum pump negative pressure vacuuming will contain more debris, which can also prevent the debris from entering the corresponding oil chamber and contaminating the lubricating oil, and prevent the lubricating oil from containing debris and affecting the normal lubrication and operation of the bearing.

[0049] See also Figure 1 , 2 As shown, the oil seal 18 includes a first annular body 19 and a second annular body 20, the first annular body 19 is sleeved on the connecting shaft 4, the outer surface of the first annular body 19 abuts against the inner wall of the pump body 3, and the inner surface of the first annular body 19 abuts against the outer surface of the connecting shaft 4;

[0050] An annular cavity 21 is provided in the middle of the inner surface of the first annular body 19, and the second annular body 20 is arranged in the annular cavity 21. One end of the second annular body 20 is connected to the inner wall of the annular cavity 21, and the inner surface of the other end of the second annular body 20 is against the outer surface of the connecting shaft 4.

[0051] A through hole 22 is provided on the outer surface of the first annular body 19 and communicates with the annular cavity 21 . The through hole 22 is arranged opposite to the second annular body 20 . A nitrogen connecting hole 23 communicated with the through hole 22 is provided on the outer wall of the pump body 3 .

[0052] The nitrogen connection hole is connected to the nitrogen source to provide nitrogen. During the rotation of the coupling, the oil seal is always in sliding contact with the coupling. If the time is long, some parts are prone to wear, resulting in poor sealing effect. Therefore, the oil seal adopts a first annular body and a second annular body, the outer end of the second annular body is connected to the inner wall of the outer end of the annular cavity (the outer end is close to the oil cavity of the corresponding side, and the inner end is far away from the oil cavity of the corresponding side), and the inner surface of the inner end of the second annular body is provided with an annular sealing lip 24, which also rests on the outer surface of the coupling. Nitrogen of a certain pressure is introduced through the nitrogen connection hole, so that the inner end of the annular sealing lip can be deformed toward the outer surface of the coupling. Even if there is slight wear at the contact between the annular sealing lip and the coupling, the annular sealing lip is always in contact with the outer surface of the coupling due to the pressure given by the nitrogen, so as to ensure the sealing effect. Even if there is micro-wear at the contact point between the first annular body and the coupling at the inner end of the annular cavity, due to the large exhaust pressure in the screw pump body cavity or the Roots pump body cavity, when the micro-gas enters the annular cavity through the micro-gap at the contact point between the first annular body and the coupling, combined with the pressure of the nitrogen, the second annular body is subjected to greater pressure, so that the annular sealing lip fits more closely with the outer surface of the coupling, thereby ensuring the sealing effect. Prevent the lubricating oil in the corresponding oil cavity from entering the screw pump body cavity or the Roots pump body cavity. It also prevents the debris in the corresponding pump body cavity from entering the corresponding oil cavity and contaminating the lubricating oil.

[0053] The screw rotor component 5 is sleeved on the outside of the connecting shaft 4, and the screw rotor component 5 is circumferentially limited on the connecting shaft 4 through splines;

[0054] An axial stopper 25 is also installed on the connecting shaft at both ends of the screw rotor component 5.

[0055] In this embodiment, the Roots rotor component and the connecting shaft are an integrated structure, and the screw rotor component is detachably connected to the connecting shaft. The circumferential limitation of the screw rotor component and the corresponding connecting shaft is achieved by splines, and the axial limitation of the screw rotor component and the connecting shaft is achieved by axial limiting members.

[0056] The axial limiting member includes a limiting ring 26 , the side wall of the limiting ring 26 abuts against the end surface of the screw rotor component 5 , and a sealing ring 27 is further provided at the contact point between the limiting ring 26 and the screw rotor component 5 .

[0057] There is a micro-gap between the screw rotor component and the connecting shaft, and the air pressure at the tail end (right side) of the screw rotor component is greater than the air pressure at the head end (left side) of the screw rotor component. This causes the problem that gas enters the head end of the screw rotor component through the micro-gap from the tail end of the screw rotor component, affecting the vacuum effect and causing a lot of noise. Therefore, the gap between the screw rotor component and the connecting shaft is blocked by setting a sealing ring to ensure the vacuum effect and stability.

[0058] Example 2: See Figure 3 As shown, a multi-axis mixing pump has a structure that is basically similar to that of the first embodiment, except that: there are three connecting shafts, the middle parts of two of the connecting shafts are arranged in the pump body between the Roots pump body cavity and the screw pump body cavity, and the two ends of the two connecting shafts respectively penetrate into the Roots pump body cavity and the screw pump body cavity and are rotatably connected to the pump body; another connecting shaft is arranged in the Roots pump body cavity, and the two ends of the connecting shaft are rotatably connected to the pump body at the two ends of the Roots pump body cavity.

[0059] Among them, its working principle is basically the same as that of application number: 202410723744X, patent name: a three-axis mixing pump.

[0060] In this embodiment, the coupling includes an intermediate coupling 30, a first coupling 31 and a second coupling 32 which are respectively arranged in parallel on both sides of the intermediate coupling 30, and the intermediate coupling and the middle sides of the first coupling are respectively inserted into the Roots pump body cavity and the screw pump body cavity, wherein the two ends of the intermediate coupling and the first coupling are respectively connected to the pump body through a double-row bearing, a single-row bearing and the Roots pump body cavity side and the screw pump body cavity side for rotation, and the two ends of the second coupling 32 are respectively connected to the pump body through bearings and the two ends of the Roots pump body cavity for rotation, wherein the right end of the second coupling is connected to the pump body through a double-row bearing, and the left side of the second coupling is connected to the pump body through a single-row bearing. The Roots pump body cavity includes a first-stage Roots pump body cavity 10 and a second-stage Roots pump body cavity 11, and the Roots rotor component also includes a first-stage Roots rotor component 12 and a second-stage Roots rotor component 13. The first-stage Roots rotor component is arranged in the first-stage Roots pump body cavity, and the second-stage Roots rotor component is arranged in the second-stage Roots pump body cavity. The two screw rotor components 5 are respectively mounted on the first connecting shaft and the intermediate connecting shaft, the two first-stage Roots rotor components are respectively mounted on the intermediate connecting shaft and the first connecting shaft, and the two second-stage Roots rotor components are respectively mounted on the intermediate connecting shaft and the second connecting shaft.

[0061] The ends of the three connecting shafts are respectively meshed with gears 14. When the motor drives one connecting shaft to rotate, the three connecting shafts rotate at the same time. The rotation directions of the first connecting shaft and the second connecting shaft are the same, but opposite to the rotation direction of the middle connecting shaft. During operation, when the two first-stage Roots rotor components rotate, the gas in the first-stage Roots pump body cavity above the first-stage Roots rotor component is pressed into the space below the two first-stage Roots rotor components, and then sent to the second-stage Roots pump body cavity through the middle connecting channel (the middle connecting channel connects the bottom of the first-stage Roots pump body cavity with the bottom of the second-stage Roots pump body cavity), which is in the second-stage Roots pump body cavity below the two second-stage Roots rotor components, and then when the two second-stage Roots rotor components rotate, the gas below them is sent into To the secondary Roots pump body cavity above the two secondary Roots rotor components, and then sent into the screw pump body cavity through the connecting channel (the connecting channel is used to connect the top of the secondary Roots pump body cavity with the left end of the screw pump body cavity), wherein there is a micro-gap between the outer surfaces of the two screw rotor components and the inner surface of the screw pump body cavity on the corresponding side, and the outer surface of the screw rotor component has a spiral groove (spiral exhaust groove), the groove width of the spiral groove gradually decreases from left to right, and the screw rotor component beside the spiral groove will mesh with the spiral groove of the adjacent screw rotor component (and there is a gap between the two and they will not contact each other), so that the gas sent into the screw pump body cavity through the connecting channel is discharged backwards through the gap of the spiral groove and sent out through the exhaust port, thereby realizing the vacuum pumping action.

[0062] In the description of the present invention, it should be understood that the terms "upper", "lower", "top", "bottom", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In the description of the present invention, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0063] In the present utility model, unless otherwise clearly specified and limited, the terms "install", "connect", "connect", "fix" and the like should be understood in a broad sense, for example, it can be a fixed connection, or a detachable connection, or an integral one; it can be a mechanical connection, or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, for example, the two can form a mechanical abutment or abutment connection through abutment, contact, etc., the two can also be directly hung or hung through an intermediate medium, etc., or it can be the internal connection of the two elements or the interaction relationship between the two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

Claims

1. A multi-axis mixing pump, comprising a pump body having a screw pump body cavity and a Roots pump body cavity, wherein at least two mutually parallel connecting shafts are rotatably mounted in the pump body, and both sides of the middle of the two connecting shafts are respectively arranged in the screw pump body cavity and the Roots pump body cavity, and screw rotor components and Roots rotor components are respectively mounted on the connecting shafts in the screw pump body cavity and the Roots pump body cavity, characterized in that: The two ends of the connecting shaft are rotatably connected to the pump body respectively, and the pump body is provided with two through holes for connecting the Roots pump body cavity with the screw pump body cavity, and the middle parts of the two connecting shafts are respectively inserted into the two through holes; One end of the connecting shaft is rotatably connected to the pump body at one end of the Roots pump body cavity via a bearing; The end of the connecting shaft located in the screw pump body cavity is rotatably connected to the pump body at one end of the screw pump body cavity via a bearing.

2. The multi-axis mixing pump according to claim 1, characterized in that: There is a micro gap between the outer surface of the connecting shaft and the inner wall of the through hole; And / or, one end of the coupling shaft is rotatably connected to the pump body at one end of the Roots pump body cavity via a double-row bearing; The end of the connecting shaft located in the screw pump body cavity is rotatably connected to the pump body at one end of the screw pump body cavity via a single-row bearing.

3. The multi-axis mixing pump according to claim 1, characterized in that: A first oil chamber is also provided in the pump body. The screw pump body chamber is provided between the first oil chamber and the Roots pump body chamber. The outer end of the bearing on the screw pump body chamber side is provided in the first oil chamber.

4. The multi-axis mixing pump according to claim 1, characterized in that: A second oil chamber is also provided in the pump body, the Roots pump body chamber is arranged between the second oil chamber and the screw pump body chamber, and the outer end of the bearing on the Roots pump body chamber side is arranged in the second oil chamber.

5. The multi-axis mixing pump according to any one of claims 1 to 4, characterized in that: An oil seal is respectively arranged on the connecting shaft on the inner side of each bearing.

6. The multi-axis mixing pump according to claim 5, characterized in that: The oil seal comprises a first annular body and a second annular body, wherein the first annular body is sleeved on the connecting shaft, the outer surface of the first annular body abuts against the inner wall of the pump body, and the inner surface of the first annular body abuts against the outer surface of the connecting shaft; An annular cavity is provided in the middle of the inner surface of the first annular body, the second annular body is arranged in the annular cavity, one end of the second annular body is connected to the inner wall of the annular cavity, and the inner surface of the other end of the second annular body abuts against the outer surface of the connecting shaft.

7. The multi-axis mixing pump according to claim 6, characterized in that: A through hole is provided on the outer surface of the first annular body and communicates with the annular cavity. The through hole is arranged opposite to the second annular body. A nitrogen connection hole communicated with the through hole is provided on the outer wall of the pump body.

8. The multi-axis mixing pump according to claim 1, characterized in that: There are two screw rotor components, the two screw rotor components are respectively installed on one connecting shaft, and the two screw rotor components are meshed with each other; The screw rotor component is sleeved on the outside of the connecting shaft, and the screw rotor component is circumferentially limited on the connecting shaft through splines; An axial limiter is also installed on the connecting shaft at both ends of the screw rotor component.

9. The multi-axis mixing pump according to claim 8, characterized in that: The axial limiting member comprises a limiting ring, the side wall of which abuts against the end surface of the screw rotor component, and a sealing ring is further provided at the contact point between the limiting ring and the screw rotor component.

10. The multi-axis mixing pump according to claim 1, characterized in that: There are two connecting shafts, the middle part of which is arranged in the pump body between the Roots pump body cavity and the screw pump body cavity, and the two ends of the connecting shaft respectively penetrate into the Roots pump body cavity and the screw pump body cavity and are rotatably connected to the pump body; Alternatively, there are three connecting shafts, the middle parts of two of the connecting shafts are arranged in the pump body between the Roots pump body cavity and the screw pump body cavity, and the two ends of the two connecting shafts respectively penetrate into the Roots pump body cavity and the screw pump body cavity and are rotatably connected to the pump body; another connecting shaft is arranged in the Roots pump body cavity, and the two ends of the connecting shaft are rotatably connected to the pump body at both ends of the Roots pump body cavity.

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