A vacuum pump

Abstract

This utility model discloses a vacuum pump, including a pump body and two sets of meshing rotor components. The pump body has a Roots pump body cavity and a screw pump body cavity, and a connecting air passage connecting the two. The rotor components include a coupling shaft, a Roots rotor component, and a screw rotor component, which are respectively disposed within the screw pump body cavity and the Roots pump body cavity. The pump body comprises a screw pump body and a Roots pump body connected to each other, with the screw pump body cavity and the Roots pump body cavity respectively disposed within the screw pump body and the Roots pump body cavity. The screw rotor component and the coupling shaft are integrally formed, and the Roots rotor component is detachably mounted on the coupling shaft. The outer wall of the screw pump body has a through cavity communicating with the screw pump body cavity, and a sealing component is detachably mounted on the screw pump body to seal the through cavity. This utility model reduces the maintenance rate and extends the service life.

Description

Technical Field

[0001] This utility model relates to a vacuum pump, and more particularly to a hybrid vacuum pump. Background Technology

[0002] Vacuum pumps are classified in many ways, and different vacuum pumps are used in different industries. For example, Roots vacuum pumps and screw vacuum pumps can be used individually or in combination. When used in combination, as in application number "202410723796.7" and patent title "A Two-Shaft Hybrid Pump," the problem of large space occupation and the use of two sets of motors in existing systems is solved. As a hybrid vacuum pump, the screw pump at the rear determines the vacuum level; therefore, the gap between the screw rotor and the screw pump body is set to be small to ensure the vacuum level. However, after a period of practical application, the following shortcomings were found: 1. When assembling a vacuum pump, the Roots pump is assembled first, followed by the screw, and then the screw pump body. However, due to the need to ensure a small gap between the screw rotor and the screw pump body, the assembly and debugging are quite difficult. Furthermore, because the screw rotor and shaft are separate structures, factors such as assembly precision, tolerances, and processes (and the assembly gap of the screw rotor is smaller than that of the Roots rotor) mean that while the initial assembly gap may be guaranteed, during use, high temperatures and impurities entering the vacuum pump can cause the screw rotor and shaft to shift or deform, leading to friction and jamming with the screw pump body. There may also be contact friction and jamming between the two meshing screw rotors, resulting in wear on both the screw rotor and the screw pump body, increasing the maintenance rate. 2. Because the screw rotor is mounted on the shaft during subsequent assembly, and then the screw pump body is installed, during use (thermal expansion and contraction), or during the installation of the screw pump body, axial displacement or deformation of the screw may occur. Since the two screw rotors are meshing, the axial distance between the two screw rotors may become too small, leading to wear, which may not be detected and increases the maintenance rate. Alternatively, if axial displacement of the screw rotor is discovered, adjusting the screw rotor axis position requires disassembling the screw pump body before adjustment. After adjustment, when reinstalling the screw pump body, the clearance between the screw pump body and the screw rotor also needs to be adjusted, which is very inconvenient and difficult to adjust. 3. After a period of use, impurities can enter the vacuum pump, especially since the gaps between the two screw rotors and between the screw rotors and the pump body are small. Impurities can easily clog the inside, leading to increased power requirements for rotation, increased energy consumption, and potential wear on the screw rotors and the pump itself. Therefore, solving these technical problems is a direction that those skilled in the art need to address. Summary of the Invention

[0003] The purpose of this invention is to provide a vacuum pump that improves assembly convenience, reduces maintenance rate, and extends service life by using this structure.

[0004] To achieve the above objectives, the technical solution adopted by this utility model is: a vacuum pump, comprising: The pump body has an independent Roots pump body cavity and a screw pump body cavity. The pump body also has a connecting air passage that connects the Roots pump body cavity and the screw pump body cavity. The pump body is respectively provided with an air inlet that communicates with the Roots pump body cavity and an air outlet that communicates with the screw pump body cavity. The rotor assembly comprises two sets of meshing rotor components. Each rotor assembly includes a coupling shaft, a Roots rotor component mounted on the coupling shaft, and a screw rotor component. The screw rotor component and the Roots rotor component are disposed within the cavity of the screw pump body. The two ends of the coupling shaft are rotatably connected to the two ends of the pump body, respectively. The pump body includes a screw pump body and a roots pump body connected to each other, wherein the screw pump body cavity is disposed within the screw pump body and the roots pump body cavity is disposed within the roots pump body; The screw rotor assembly and the connecting shaft are an integral structure, and the Roots rotor assembly is detachably mounted on the connecting shaft; The outer wall of the screw pump body is provided with a through cavity communicating with the screw pump body cavity. The through cavity is positioned directly opposite the two sets of screw rotor components. A sealing component that seals the through cavity is detachably installed on the screw pump body.

[0005] In the above technical solution, the end of the connecting air passage is provided with at least one connecting air passage outlet communicating with the screw pump body cavity. The connecting air passage outlet is located on the end face of the Roots pump body facing the screw pump body cavity, and the connecting air passage outlet is arranged parallel to the axis of the connecting shaft.

[0006] In the above technical solution, there are two connecting air passage outlets, and two connecting shafts are arranged between the two connecting air passage outlets. Each connecting air passage outlet is respectively arranged opposite to a set of screw rotor components. And / or, the connecting air passage outlet is positioned directly opposite the edge of the corresponding screw rotor component.

[0007] In the above technical solution, the inner surface of the sealing component is flush with the inner surface of the screw pump body cavity; And / or, the blocking component includes a blocking block and a connecting block disposed at one end of the blocking block, the blocking block being adapted to the through cavity, the blocking block being inserted into the through cavity, the connecting block being disposed outside the through cavity, and the connecting block being connected to the screw pump body via fasteners.

[0008] In the above technical solution, the outer wall of the screw pump body is also provided with a pressure relief channel communicating with the screw pump body cavity, and a one-way valve is provided in the pressure relief channel; And / or, the pressure relief channel is located close to the Roots pump body.

[0009] In the above technical solution, the through cavity is located at the bottom of the screw pump body, and the pressure relief channel is located at the top of the screw pump body; And / or, the one-way valve is a float valve.

[0010] In the above technical solution, the Roots rotor assembly includes a first-stage Roots rotor assembly, a second-stage Roots rotor assembly, and an intermediate assembly, all of which are integrally structured. The intermediate assembly connects the first-stage and second-stage Roots rotor assemblies. The Roots pump body includes a first-stage pump body and a second-stage pump body that are interconnected. The second-stage pump body is disposed between the first-stage pump body and the screw pump body. The Roots pump body cavity includes a first-stage Roots pump body cavity and a second-stage Roots pump body cavity. The first-stage Roots pump body cavity is disposed within the first-stage pump body, and the second-stage Roots pump body cavity is disposed within the second-stage pump body. The first-stage Roots rotor assembly is disposed within the first-stage Roots pump body cavity, and the second-stage Roots rotor assembly is disposed within the second-stage Roots pump body cavity. A partition is also provided between the first-stage pump body and the second-stage pump body. The partition is disposed inside the pump body and has through holes that cooperate with the intermediate component.

[0011] In the above technical solution, the Roots pump body is provided with an intermediate air passage connecting the first-stage Roots pump body cavity and the second-stage Roots pump body cavity; The air inlet is connected to the top of the first-stage Roots pump body cavity; The intermediate air passage includes a primary intermediate air passage and a secondary intermediate air passage. The primary intermediate air passage is disposed within the primary pump body, with its inlet connected to the bottom of the primary Roots pump body cavity and its outlet connected to the end face of the primary pump body facing the secondary pump body. The secondary intermediate air passage is disposed within the secondary pump body outside the secondary Roots pump body cavity, with its inlet facing the primary pump body and connected to the outlet of the primary intermediate air passage. The outlet of the secondary intermediate air passage is connected to the top of the secondary Roots pump body cavity. The connecting air passage is located inside the secondary pump body, and the inlet of the connecting air passage is connected to the bottom of the secondary Roots pump body cavity.

[0012] In the above technical solution, a sealing element is provided at the connection between the screw pump body and the secondary Roots pump body, and a sealing element is also provided at the connection between the primary pump body and the secondary pump body; And / or, the partition is disposed inside the seal between the primary pump body and the secondary pump body.

[0013] In the above technical solution, the Roots rotor component is provided with a mounting hole, and the two ends of the mounting hole are respectively connected to the two ends of the Roots rotor component in the axial direction. The Roots rotor component is mounted on the corresponding coupling through the mounting hole. The inner surface of the mounting hole is provided with a first positioning element, and the connecting shaft is provided with a second positioning element that cooperates with the first positioning element. The first positioning element and the second positioning element restrict the rotation of the Roots rotor component relative to the connecting shaft.

[0014] In the above technical solution, the two connecting shafts are arranged parallel to each other, the two screw rotor components arranged in the screw pump body cavity mesh with each other, and the two Roots rotor components arranged in the Roots pump body cavity mesh with each other.

[0015] Due to the application of the above technical solution, this utility model has the following advantages compared with the prior art: 1. In this utility model, the rotor component and the coupling shaft are set as an integrated structure, and the Roots rotor component is separately and detachably installed on the coupling shaft. Compared with the previous structure of the Roots rotor component and the coupling shaft being integrated, and the screw rotor component being separately and detachably installed on the coupling shaft, the assembly difficulty is lower, the assembly precision of the screw rotor component and the screw pump body is also higher, and the mutual friction between the screw rotor components and the screw pump body is less likely to occur during subsequent use, effectively reducing the maintenance rate, extending the service life, and reducing the difficulty of assembly and debugging; 2. In this utility model, the airflow direction entering the screw pump cavity from the Roots pump body cavity is set parallel to the axial direction of the rotor component. Compared with the previous method of air intake perpendicular to the rotor component axis, it can effectively reduce the radial pressure on the coupling, effectively prevent the coupling deformation, extend service life, and reduce maintenance rate. 3. In this invention, the airflow direction entering the screw pump cavity from the Roots pump body cavity is set parallel to the axial direction of the rotor component. The gas can fully contact the end face of the screw rotor component. During the rotation of the screw rotor component, the gas enters completely from the helical groove of the screw rotor component. The gas fully contacts the helical groove of the screw rotor component, thereby reducing the pressure of the gas entering the helical groove of the screw rotor component from the Roots pump body cavity, reducing the impact force on the screw rotor component, and lowering the temperature at this location, extending the service life and reducing the maintenance rate. 4. In this utility model, there are two airflow outlets (connecting air passage outlets) entering the screw pump cavity from the Roots pump body cavity, which are respectively facing the two screw rotor components. This disperses the air intake, which can effectively reduce the impact force of gas on the screw rotor components, extend service life, and reduce maintenance rate. 5. In this utility model, a through cavity communicating with the screw pump body is provided on the screw pump body. A sealing component that seals the through cavity is detachably installed in the through cavity. After the screw rotor assembly and the screw pump body cavity are assembled, it is convenient to adjust the axial and radial direction of the screw rotor assembly during the subsequent assembly of the Roots rotor assembly and the Roots pump body, ensuring assembly accuracy. At the same time, it is also easy to carry out subsequent maintenance, observation and cleaning. 6. In this utility model, the through cavity is set at the bottom of the screw pump body, and the pressure relief channel is set at the top of the screw pump body. The one-way valve in the pressure relief channel is a float valve. Compared with the bottom-mounted pressure relief channel, it can reduce the space occupation and facilitate the installation of the float valve. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure in Embodiment 1 of this utility model; Figure 2 yes Figure 1 A bottom view; Figure 3 yes Figure 2 A sectional view; Figure 4 yes Figure 1 A sectional view; Figure 5 This is a schematic diagram of the Roots rotor component in Embodiment 1 of this utility model; Figure 6 yes Figure 2 A cross-sectional structural diagram of the screw pump body; Figure 7 This is a schematic diagram of the screw pump body in Embodiment 1 of this utility model (some components are not shown). Figure 8 yes Figure 7 A cross-sectional three-dimensional structural diagram; Figure 9 This is a schematic diagram of the structure of the secondary pump body in Embodiment 1 of this utility model (the maintenance block is not shown). Figure 10 This is a three-dimensional structural diagram of the secondary pump body in Embodiment 1 of this utility model (the maintenance block is not shown). Figure 11 This is another three-dimensional structural diagram of the secondary pump body in Embodiment 1 of this utility model (the maintenance block is not shown); Figure 12 yes Figure 9 A cross-sectional view of the structure (at the secondary intermediate airway). Figure 13 yes Figure 9 A cross-sectional view of the structure (at the airway connection).

[0017] The components are: 1. Pump body; 11. Roots pump body cavity; 12. Screw pump body cavity; 13. Connecting air passage; 14. Air inlet; 15. Exhaust port; 16. Connecting air passage outlet; 111. First-stage Roots pump body cavity; 112. Second-stage Roots pump body cavity; 2. Rotor assembly; 21. Coupling; 22. Roots rotor assembly; 23. Screw rotor assembly; 24. Limiting ring; 221. First-stage Roots rotor assembly; 222. Second-stage Roots rotor assembly; 223. Intermediate component; 224. Mounting hole; 225. First positioning component; 31. Screw pump body; 310. Pressure relief channel; 311. Check valve; 32. Roots pump body; 321. Primary pump body; 322. Secondary pump body; 4. Cavity; 41. Blocking component; 42. Blocking block; 43. Connecting block; 5. Partition; 51. Primary intermediate airway; 52. Secondary intermediate airway; 53. Inspection port; 54. Inspection block. Detailed Implementation

[0018] The present invention will be further described below with reference to the accompanying drawings and embodiments: Example 1: See Figure 1-13 As shown, a vacuum pump includes a pump body 1 and a rotor assembly 2; The pump body 1 is provided with an independent Roots pump body cavity 11 and a screw pump body cavity 12. The pump body 1 is also provided with a connecting air passage 13 that connects the Roots pump body cavity 11 and the screw pump body cavity 12. The pump body 1 is provided with an air inlet 14 that communicates with the Roots pump body cavity 11 and an exhaust port 15 that communicates with the screw pump body cavity 12. The rotor component 2 consists of two sets, which mesh with each other. The rotor component 2 includes a connecting shaft 21, a Roots rotor component 22 mounted on the connecting shaft 21, and a screw rotor component 23. The screw rotor component 23 is disposed in the screw pump body cavity 12, and the Roots rotor component 22 is disposed in the Roots pump body cavity 11. The two ends of the connecting shaft 21 are rotatably connected to the two ends of the pump body 1, respectively.

[0019] The pump body 1 includes a screw pump body 31 and a roots pump body 32 that are sealed together. The screw pump body cavity 12 is disposed inside the screw pump body 31, and the roots pump body cavity 11 is disposed inside the roots pump body 32. The screw rotor component 23 and the connecting shaft 21 are an integral structure, and the Roots rotor component 22 is detachably mounted on the connecting shaft 21; The outer wall of the screw pump body 31 is provided with a through cavity 4 that communicates with the screw pump body cavity 12. The through cavity 4 is positioned directly opposite the two sets of screw rotor components 23. A sealing component 41 that seals the through cavity 4 is detachably installed on the screw pump body 31.

[0020] In this invention, the vacuum pump is a hybrid vacuum pump combining a Roots vacuum pump and a screw vacuum pump. The two are directly connected together without any intermediate piping, and can be driven by a single power unit. (See attached diagram.) Figure 1 Taking the direction as an example, the left side of the Roots pump body is sealed and fixedly connected to the right side of the screw pump body. The Roots rotor assembly is located outside the coupling on the right side of the screw rotor assembly. Simultaneously, a power unit is installed at the right end of the Roots pump body. This power unit can be a motor, or a combination of a motor and a reducer. The power unit is connected to the right end of one of the couplings to drive its rotation. Gears are installed at either the left or right end of the two couplings, meshing with each other. Therefore, when the power unit drives one coupling to rotate, the other coupling will rotate via the gears, meaning both sets of rotor assemblies rotate simultaneously in opposite directions. Bearings are installed at both ends of the couplings for rotatable connection to the pump body. During operation, the rotation of both sets of rotor assemblies, the meshing of the two screw rotor assemblies, and the meshing of the Roots rotor assemblies achieve vacuuming. The gas flow path is as follows: the gas enters the Roots pump body cavity from the inlet, is sent to the connecting air passage by the screw rotor assembly, enters the screw pump body cavity through the connecting air passage, and is finally sent out from the exhaust port by the screw rotor assembly, thereby evacuating the space required for evacuation at the inlet.

[0021] In this embodiment, the screw rotor assembly and the coupling are an integral structure. During machining, the screw structure (screw rotor assembly) is directly machined on the outer left surface of the coupling, while the Roots rotor assembly is machined separately. Specifically, in this embodiment, the right end face of the screw pump body cavity is connected to the right end face of the screw pump body. The left end of the screw pump body has two holes communicating with the screw pump body cavity. These two holes are used for mounting the two couplings. An end cap is also provided at the left end of the screw pump body to seal it. A chamber is provided inside the end cap to accommodate the left end of the coupling and the gear on the left end of the coupling (in this embodiment, the gear is mounted on the left end of the coupling, located on the outer left side of the screw pump body, within the chamber of the end cap). During assembly, first insert the left end of the coupling into the screw pump body cavity from the right end, passing through the hole outside the left end of the screw pump body. Simultaneously, install a bearing within the hole to provide rotational support for the left end of the coupling. At this point, the screw rotor assembly is inside the screw pump body cavity (the sealing components are not installed yet). Then install the Roots pump body and Roots rotor assembly. During the installation of the Roots pump body and Roots rotor assembly, the axial distance between the two sets of screw rotor assemblies can be observed through the through-cavity (the side of the screw rotor assembly will be inserted into another set of screw rotor assemblies). If there is a deviation in the axial spacing between the helical grooves of the screw rotor assembly and another screw rotor assembly, then during subsequent use, or due to high temperatures or other reasons, rotational jamming or mutual wear may occur. This is to ensure good assembly clearance between the two sets of screw rotor assemblies and the two sets of Roots rotor assemblies, as well as good assembly clearance between the screw rotor assembly and the screw pump body cavity, and between the Roots rotor assembly and the Roots pump body cavity. Then, gears, end covers, sealing components, power units, etc. can be installed. In this method, the screw rotor assembly and coupling are integrated into a single structure, with the Roots rotor assembly detachably mounted on the coupling. Compared to the previous structure where the screw rotor assembly was detachably connected to the coupling and the Roots rotor assembly was integrated with the coupling, this method allows for improved assembly precision by assembling the screw rotor assembly and screw pump body first, followed by the Roots rotor assembly and Roots pump body. (The screw vacuum pump is located at the rear end of the Roots vacuum pump; therefore, the screw rotor assembly is at the rear end. The assembly precision of the two screw rotor assemblies, as well as the clearance between the screw rotor assembly and the screw pump body cavity, determines the overall vacuum pump's performance.) The vacuum level of the empty pump means that the gaps between the two screw rotor components and between the screw rotor component and the screw pump body cavity will be smaller, while the gaps between the two Roots rotor components and between the Roots rotor component and the Roots pump body cavity will be larger (larger than the gap between the screw rotor components). In the past, the Roots rotor component and the Roots pump body were assembled first, followed by the screw rotor component and the screw pump body. This made assembly and debugging more difficult, and it was hard to guarantee the gaps between the two screw rotor components and between the screw rotor component and the screw pump body cavity. The assembly and debugging were also more difficult.In this embodiment, the screw rotor assembly and the screw pump body are installed first to facilitate adjustment of the clearance value. This ensures the clearance value of the screw rotor assembly and the clearance value between the screw rotor assembly and the screw pump body cavity. When the Roots rotor assembly and the Roots pump body are installed later, the larger clearance value between the Roots rotor assembly and the Roots pump body cavity prevents friction between the two Roots rotor assemblies and between the Roots rotor assembly and the Roots pump body cavity. Once the vacuum degree of the screw vacuum pump is guaranteed, the vacuum degree of the entire vacuum pump during operation can be guaranteed.

[0022] Furthermore, during the installation of the Roots rotor assembly and the Roots pump body, the position and clearance of the screw rotor assembly within the screw pump body cavity can be observed through the through-cavity. This facilitates adjustment of the axial distance between the two connecting shafts and allows for fine-tuning of the connecting shafts to ensure the clearance values ​​between the two screw rotor assemblies and between the screw rotor assembly and the screw pump body cavity. During subsequent use, the sealing components can be directly disassembled, allowing operators to directly inspect the clearance values ​​between the two screw rotor assemblies and between the screw rotor assembly and the screw pump body cavity through the through-cavity. This also allows for checking for internal blockages and cleaning of the screw pump body cavity without removing the rotor assembly from the screw pump body cavity, making maintenance, cleaning, and maintenance more convenient. Additionally, if an axial clearance problem occurs with the screw rotor assembly, only the end cover needs to be removed, and the axial position of the connecting shaft adjusted to correct the axial clearance of the screw rotor assembly, without requiring the entire vacuum pump to be disassembled.

[0023] See Figure 3 , 11 As shown, the end of the connecting air passage 13 is provided with at least one connecting air passage outlet 16 communicating with the screw pump body cavity 12. The connecting air passage outlet 16 is disposed on the end face of the Roots pump body 32 facing the screw pump body cavity 12, and the connecting air passage outlet 16 is disposed parallel to the axis of the connecting shaft 21.

[0024] Figure 1In this configuration, the connecting air outlet is located on the left end face of the Roots pump body, directly connecting to the right end of the screw pump cavity. The connecting air outlet is parallel to the axis of the coupling. Due to the high velocity and pressure of the gas entering the screw pump cavity, the gas direction from the Roots pump cavity to the screw pump cavity is not perpendicular to the coupling. This effectively reduces the radial impact of the gas on the coupling, preventing coupling deformation, extending its service life, preventing wear between the screw rotor components and the screw pump cavity caused by coupling deformation, reducing maintenance rates, and extending service life. Meanwhile, the connecting air outlet is set parallel to the coupling shaft, allowing the gas to directly contact the end face of the screw rotor assembly. As the screw rotor assembly rotates, the gas flows along the spiral grooves of the screw rotor assembly (the exhaust port is located on the left side of the screw pump body cavity). Therefore, the gas can directly and completely contact the right end face of the spiral grooves of the screw rotor assembly. When the screw rotor assembly rotates, the gas can smoothly flow to the left along the spiral grooves and be discharged from the exhaust port, resulting in a longer service life and less deformation (in previous structures, the gas delivered from the Roots pump body cavity would enter the screw pump body cavity perpendicular to the coupling shaft. During this process, the gas pressure entering the screw pump body cavity would be relatively high, while the diameter of the coupling shaft would not be...). With such large settings, the coupling is subjected to radial force from the airflow for extended periods, making it prone to deformation (even slight deformation). This deformation can lead to friction between the two screw rotors or between the screw rotor and the pump body, causing jamming and wear, resulting in high maintenance rates and short service life. Furthermore, because the screw rotor has a helical structure, the helical gaps within it form the gas flow path. Due to the radial air intake, the gas entering the pump body cavity can only enter through a portion of the helical grooves of the screw rotor. This results in higher exhaust pressure during vacuuming, higher temperatures within the pump, and greater radial pressure on the coupling at that point, making it more susceptible to deformation.

[0025] See Figure 3 , 11As shown, there are two connecting air outlets 16, and two connecting shafts 21 are arranged between the two connecting air outlets 16. Each connecting air outlet 16 is respectively positioned opposite a set of screw rotor components 23. In the original structure, there is only one connecting air outlet, which is perpendicular to the connecting shaft. Therefore, when the gas enters the screw pump cavity, since only a portion of the contact position with the spiral groove of the screw rotor component is reached, the gas flow rate into the spiral groove of the screw rotor component is faster, the impact force on the connecting shaft is greater, the temperature rises faster, the temperature is higher, and it is more prone to deformation. In this embodiment, the arrangement of two connecting air outlets can slow down the flow rate of gas entering the spiral groove inside the screw pump body cavity from the corresponding connecting air outlet, thereby reducing the impact force on the end face of the screw rotor component (the screw rotor component rotates, and the gas directly contacts the end face of the screw rotor component, thus allowing the gas to directly contact the end face of the spiral groove, resulting in smooth gas flow). Furthermore, the end face of each set of screw rotor components bears the impact of the airflow from one connecting air outlet, which can share the impact force. In addition, the axial impact resistance of the screw rotor component is also stronger, it is not easily deformed, has a long service life, and a low maintenance rate.

[0026] Meanwhile, the connecting air outlet is positioned directly opposite the edge of the corresponding screw rotor component. This alignment with the edge of the screw rotor component allows for smooth gas flow along the helical grooves of the screw rotor component during rotation. Furthermore, the two connecting air outlets are spaced far apart to minimize interference between the gases emitted from them at the end face of the screw rotor component, ensuring smooth gas flow into the helical grooves, minimizing the impact force on the end face of the screw rotor component, preventing deformation (and enhancing the screw rotor component's deformation resistance), extending its service life, and reducing maintenance frequency.

[0027] In this configuration, the inner surface of the sealing component is flush with the inner surface of the screw pump body cavity. This method involves installing the sealing component after the rotor assembly and pump body are assembled, ensuring that the inner surface of the sealing component is flush with the inner surface of the screw pump body cavity. When the vacuum pump is in use, the sealing component forms an integral part of the screw pump body, making the gap between the outer surface of the screw rotor assembly facing the through cavity and the sealing component equal to the gap between the screw rotor assembly and the screw pump body cavity, thus guaranteeing a vacuum pumping effect.

[0028] See Figure 4 , 6 As shown, the blocking component 41 includes a blocking block 42 and a connecting block 43 disposed at one end of the blocking block 42. The blocking block 42 is adapted to the through cavity 4 and is inserted into the through cavity 4. The connecting block 43 is disposed outside the through cavity 4 and is connected to the screw pump body 31 by fasteners.

[0029] The sealing block and connecting block are integrated into a single unit, forming a T-shape. The connecting block is larger than the sealing block and the through-cavity. The outer wall of the sealing block contacts the inner wall of the through-cavity, while the connecting block is located outside the through-cavity. The sealing component is then secured to the screw pump body using fasteners such as pins and bolts. This structure allows for quick installation and removal of the sealing component.

[0030] In previous designs, because the screw rotor assembly and coupling were separate components, installation required assembling the screw rotor assembly and coupling first, followed by assembling the screw pump body. After installation, due to operator error, product tolerances, or other factors, it was unclear whether the clearance between the screw rotor assembly and the pump body cavity was acceptable, exceeded the preset value, or whether the axial clearance between the two screw rotor assemblies had changed. If the clearance was too close (which was normal during assembly), after a period of use, thermal expansion could cause friction. Subsequent maintenance would require disassembling and reinstalling the screw pump body, potentially leading to repeated problems. Therefore, in this utility model, a through cavity is provided so that during the assembly process, it is possible to observe whether the assembly is qualified or whether the spacing value is qualified. During subsequent maintenance, the pump body does not need to be disassembled. Only the sealing component needs to be disassembled and the screw pump body cavity needs to be opened for inspection. If only the axial clearance adjustment is involved, only the end cover at the end of the pump body needs to be removed and the axial position of the coupling needs to be adjusted. This also facilitates maintenance and eliminates the need for complete disassembly and assembly again.

[0031] See Figure 4 , 8 As shown, the outer wall of the screw pump body 31 is also provided with a pressure relief channel 310 communicating with the screw pump body cavity 12. The pressure relief channel 310 is provided with a one-way valve 311, which is a float valve. The pressure relief channel 310 is located near the Roots pump body 32.

[0032] When the vacuum pump set first starts working, the gas pressure at the outlet of the large-volume vacuum pump at the front end is relatively high (the vacuum pump set consists of multiple vacuum pumps connected together, with a large-volume vacuum pump at the front end and a small-volume vacuum pump at the rear end to improve the vacuum level). The pumping capacity of the screw pump is less than that of the Roots pump. Therefore, at the beginning of operation, the gas pressure delivered by the Roots pump body at the front end of the vacuum pump is relatively high. However, the exhaust volume of the screw rotor assembly is less than the gas volume delivered by the Roots pump body. At this time, the screw pump body cannot expel the gas in time, leading to uneven vacuuming and affecting the vacuuming effect. Therefore, a pressure relief channel is set up, with a one-way valve installed inside, close to the Roots pump body. Preferably, the pressure relief channel is located between the end face of the screw rotor assembly and the Roots pump body, which can discharge the gas that the screw pump body cannot expel in time, ensuring smooth vacuuming and guaranteeing the vacuuming effect. The one-way valve can only exhaust gas, not allow gas to enter, and it only opens to exhaust gas when the gas pressure reaches a certain level.

[0033] See Figure 4 , 6 As shown in Figures 8 and 9, the through cavity 4 is located at the bottom of the screw pump body 31, and the pressure relief channel 310 is located at the top of the screw pump body 31.

[0034] In this structure, the through cavity and the pressure relief channel are arranged opposite each other and not on the same surface, which facilitates layout. In addition, the check valve is a float valve, which is directly set at the top. This makes the structure simpler and the cost relatively lower (if the pressure relief channel is set at the bottom and the check valve is a float valve, the structure of the pressure relief channel will be more complex, occupy more space, be more difficult to process, and be more expensive).

[0035] See Figure 3-5 As shown, the Roots rotor assembly 22 includes a first-stage Roots rotor assembly 221, a second-stage Roots rotor assembly 222, and an intermediate assembly 223, all of which are integrally formed. The intermediate assembly 223 connects the first-stage Roots rotor assembly 221 and the second-stage Roots rotor assembly 222. The Roots pump body 32 includes a first-stage pump body 321 and a second-stage pump body 322 that are interconnected. The second-stage pump body 322 is disposed between the first-stage pump body 321 and the screw pump body 31. The Roots pump body cavity 11 includes a first-stage Roots pump body cavity 111 and a second-stage Roots pump body cavity 112. The first-stage Roots pump body cavity 111 is disposed within the first-stage pump body, and the second-stage Roots pump body cavity 112 is disposed within the second-stage pump body 322. The first-stage Roots rotor component 221 is disposed within the first-stage Roots pump body cavity 111, and the second-stage Roots rotor component 222 is disposed within the second-stage Roots pump body cavity 112. A partition 5 is also provided between the first-stage pump body 321 and the second-stage pump body 322. The partition 5 is disposed inside the pump body 1 and has a through hole that cooperates with the intermediate component 223.

[0036] The Roots pump body 32 is provided with an intermediate air passage connecting the first-stage Roots pump body cavity 111 and the second-stage Roots pump body cavity 112.

[0037] The air inlet is connected to the top of the first-stage Roots pump body cavity; The intermediate air passage includes a primary intermediate air passage 51 and a secondary intermediate air passage 52. The primary intermediate air passage 51 is disposed inside the primary pump body 321. The inlet of the primary intermediate air passage 51 is connected to the bottom of the primary Roots pump body cavity 111, and the outlet of the primary intermediate air passage 51 is connected to the end face of the primary pump body 321 facing the secondary pump body 322. The secondary intermediate air passage 52 is disposed inside the secondary pump body 322 outside the secondary Roots pump body cavity 112. The inlet of the secondary intermediate air passage 52 is located facing the primary pump body 321, and the inlet of the secondary intermediate air passage 52 is connected to the outlet of the primary intermediate air passage 51. The outlet of the secondary intermediate air passage 52 is connected to the top of the secondary Roots pump body cavity 112. The connecting air passage 13 is disposed inside the secondary pump body 321, and the inlet of the connecting air passage 13 is connected to the bottom of the secondary Roots pump body cavity 112.

[0038] In this embodiment, the Roots pump body is a two-stage Roots pump body, and the rotation direction of the first-stage Roots rotor component and the second-stage Roots rotor component is the same. Therefore, when the vacuum pump is working, the gas flow path is as follows: the gas enters from the inlet into the top of the first-stage Roots pump body cavity above the two sets of first-stage Roots rotor components. After the two sets of first-stage Roots rotor components rotate, the gas flows downward to the first-stage Roots pump body cavity below the two sets of first-stage Roots rotor components, and is sent into the second-stage Roots pump body cavity above the two sets of second-stage Roots rotor components through the first-stage intermediate gas channel and the second-stage intermediate gas channel. After the two sets of second-stage Roots rotor components rotate, the gas flows downward to the second-stage Roots pump body cavity below the two sets of second-stage Roots rotor components, and enters the inlet of the connecting gas channel. After passing through the connecting gas channel, it is sent from the outlet of the connecting gas channel into the screw pump body cavity at the right end of the screw rotor component. Through the rotation of the two sets of screw rotor components, the gas flows to the left along the spiral groove of the screw rotor component and is sent out from the exhaust port.

[0039] The connection between the screw pump body and the secondary pump body is equipped with a seal, and the connection between the primary pump body and the secondary pump body is also equipped with a seal. In this design, gas flows along the corresponding channels without leakage, thus ensuring a proper vacuum.

[0040] In this embodiment, the left end of the first-stage Roots pump cavity is connected to the left end face of the first-stage pump body. The right end of the first-stage pump body has two holes communicating with the first-stage Roots pump cavity. These holes are used for the rotational support of the right ends of the two connecting shafts. The inlet of the first-stage intermediate air passage is located at the right end of the first-stage intermediate air passage, and the outlet of the first-stage intermediate air passage is located at the left end of the first-stage intermediate air passage. The top of the inlet of the first-stage intermediate air passage is connected to the bottom of the first-stage Roots pump cavity, and the outlet of the first-stage intermediate air passage is connected to the left end face of the first-stage pump body and is located below the first-stage Roots pump cavity. The right end of the second-stage Roots pump cavity is connected to the right end face of the second-stage pump body. The left end of the second-stage pump body has two holes communicating with the second-stage Roots pump cavity. These holes are used for the passage and clearance of the two connecting shafts. The secondary intermediate air passage surrounds the secondary pump body outside the secondary Roots pump body cavity. The inlet of the secondary intermediate air passage is located below the secondary Roots pump body cavity. The inlet of the secondary intermediate air passage is connected to the right end face of the secondary pump body and is directly opposite the outlet of the primary intermediate air passage. After the primary pump body is connected to the secondary pump body, the secondary intermediate air passage and the primary intermediate air passage are connected. The outlet of the secondary intermediate air passage is located above the secondary Roots pump body cavity and is connected to the top of the secondary Roots pump body cavity, so that gas sent out from the bottom of the primary Roots pump body cavity can enter from the top of the secondary Roots pump body cavity.

[0041] The connecting air passage is located in the secondary pump body at the left end of the secondary Roots pump body cavity. The inlet of the connecting air passage is connected to the bottom of the secondary Roots pump body cavity, and the outlet of the connecting air passage is connected to the left end face of the secondary pump body. This allows the gas in the secondary Roots pump body cavity to be sent out to the screw pump body cavity. More preferably, in order to facilitate the processing and manufacturing of the secondary pump body, at least one inspection port 53 connected to the secondary intermediate air passage is provided on the outer wall of the secondary pump body. The secondary pump body is equipped with an inspection plug 54 to seal the inspection port. In this way, the production and manufacturing of the secondary pump body is convenient. At the same time, due to the working environment of the vacuum pump, if the working environment is harsh, there may be some dust and other debris in the intermediate air passage, connecting air passage, Roots pump body cavity, and screw pump cavity. Therefore, the inspection port can also be used to inspect and clean the secondary intermediate air passage.

[0042] Since the primary and secondary intermediate airways are connected, the primary intermediate airway can be cleaned at the same time as the secondary intermediate airway when it is being cleaned through the inspection port.

[0043] Of course, since the inspection port can be connected to the Roots pump body cavity, screw pump body cavity, air inlet, and exhaust port through the intermediate air passage, the inspection port can also be opened to introduce cleaning fluid from the air inlet, inspection port, and exhaust port, thereby enabling the cleaning of the Roots pump body cavity, screw pump body cavity, screw rotor components, and Roots rotor components. Tilting is more convenient and the effect is better.

[0044] See Figure 3 , 4 As shown, the partition is disposed inside the seal between the primary pump body and the secondary pump body. In this embodiment, grooves are provided on the left end face of the primary pump body and the right end face of the secondary pump body. The size of the grooves is larger than the size of the corresponding Roots pump body cavity and communicates with the corresponding Roots pump body cavity. The grooves are used to accommodate the outer edge of the partition, so that the partition will not leak after the primary pump body and the secondary pump body are connected, thus not increasing the length of the pump body and reducing the space occupied. At the same time, the seal is preferably an elastic seal, such as a rubber ring, which plays a sealing role and prevents air leakage. Meanwhile, there may be a micro gap between the partition and the pump body. This micro gap is the assembly gap. These small distances mean that even if some gas enters the secondary Roots pump body cavity from the primary Roots pump body cavity through the micro gap between the partition and the pump body, it will not affect the vacuum degree.

[0045] The first-stage and second-stage Roots rotor components have identical cross-sectional structures, both being figure-eight shaped (though a three-lobe structure is also possible). The intermediate component has a circular cross-section, with an outer diameter smaller than the length of the first-stage and second-stage Roots rotor components but larger than their width. The partition consists of two symmetrically arranged half-plates. Each half-plate has a groove on its outer surface and two arc-shaped grooves on its inner side. These grooves face each other, with each groove abutting against the outer surface of one side of the intermediate component. The arc-shaped grooves on one half-plate and the other half-plate form a through-hole to allow space for the intermediate component. Using two half-plates as the partition facilitates assembly. Furthermore, the circular cross-section of the intermediate component matches the through-hole, ensuring smooth rotation of the rotor components.

[0046] See Figure 3-5 As shown, the Roots rotor component 22 is provided with a mounting hole 224. The two ends of the mounting hole 224 are respectively connected to the two ends of the Roots rotor component 22 in the axial direction. The Roots rotor component 22 is mounted on the corresponding connecting shaft 21 through the mounting hole 224. The inner surface of the mounting hole 224 is provided with a first positioning element 225, and the connecting shaft 21 is provided with a second positioning element that cooperates with the first positioning element 225. The first positioning element 225 and the second positioning element restrict the rotation of the Roots rotor component 22 relative to the connecting shaft 21.

[0047] In this embodiment, the first positioning element and the second positioning element are a keyway and a spline, or a spline and a keyway, respectively. In this embodiment, the first positioning element is a keyway, with both ends of the keyway communicating with the two ends of the mounting hole along its axial direction. The spline extends along the axis of the connecting shaft and can be directly integrated with the connecting shaft. Alternatively, a keyway can also be provided on the connecting shaft, with one side of the spline directly engaging with the keyway of the connecting shaft and the other side engaging with the keyway of the mounting hole. Through the first and second positioning elements, the Roots rotor component can be limited on the connecting shaft, so that when the connecting shaft rotates, it synchronously drives the Roots rotor component to rotate, thus playing a role in circumferential rotation limiting.

[0048] Furthermore, two limiting rings 24 are also fitted on the connecting shaft. The two limiting rings are respectively set at both ends of the Roots rotor component. Taking the illustrated direction as an example, the left limiting ring is set between the left end of the Roots rotor component and the right end of the screw rotor component. The two ends of the limiting ring are in contact with the screw rotor component and the Roots rotor component, respectively. The right limiting ring is set between the right end of the Roots rotor component and the bearing on the right side of the connecting shaft. Its two ends are in contact with the inner ring of the Roots rotor component and the bearing, respectively. The two limiting rings are used to restrict the axial movement of the Roots rotor component relative to the connecting shaft.

[0049] The two connecting shafts are arranged parallel to each other, the two screw rotor components located in the screw pump body cavity mesh with each other, and the two Roots rotor components located in the Roots pump body cavity mesh with each other.

[0050] In this embodiment, the steps for assembling the vacuum pump are as follows: S1. First, assemble the two screw rotor components and install them into the screw pump body. At this time, the left end of the connecting shaft is rotatably connected to the left end of the screw pump body through the bearing, and the left end of the connecting shaft is outside the left end of the screw pump body. S2. Connect the left end of the secondary pump body to the right end of the screw pump body. During this process, the right end of the coupling passes through the hole at the left end of the secondary pump body and passes through the cavity of the secondary Roots pump body to the outside of the right end of the secondary pump body. S3. Place the limiting ring on the connecting shaft, and make the left end of the limiting ring abut against the right end face of the screw rotor component. This step can also be assembled before step S2. S4. Place the Roots rotor assembly onto the corresponding connecting shaft from right to left. While the Roots rotor assembly is moving to the left along the connecting shaft, and before the secondary Roots rotor assembly has fully entered the secondary Roots pump body cavity, install the partition plate on the intermediate component between the primary and secondary Roots rotor assemblies. Then continue to push the Roots rotor assembly to the left along the connecting shaft until the left end of the secondary Roots rotor assembly contacts the left-side limiting ring. At this time, the left end of the partition plate is in the groove of the secondary pump body. S5. Connect the primary pump body and the secondary pump body. During this process, the primary Roots rotor component is inserted into the primary Roots pump body cavity. At the same time, the right end of the connecting shaft passes through the hole of the primary pump body and is located outside the right end of the primary pump body. Furthermore, a bearing is installed on the outer surface of the right end of the connecting shaft, which is located between the connecting shaft and the hole of the primary pump body. S6. During steps S2 and / or S5, the operator observes the gap between the two screw rotor components and the gap between the screw rotor component and the screw pump body cavity from the through cavity, and adjusts the position of the coupling shaft in real time to ensure that the gap between the two screw rotor components, the gap between the screw rotor component and the screw pump body cavity, the gap between the two Roots rotor components, and the gap between the Roots rotor component and the Roots pump body cavity are qualified. S7. After the gap adjustment is completed, install the sealing component in the passage cavity; and install the check valve, or pre-install the check valve before step S1. S8, or step S7 can be the last step. After step S6 or step S7, a gear can be installed on the left end of the coupling, and then an end cover can be installed on the left end of the screw pump body. S9. Install an end cover on the right end of the first-stage pump body. After the end cover is installed, install the power unit and connect it to a coupling to complete the assembly of the vacuum pump.

[0051] Of course, during the assembly of the vacuum pump, the order of steps S1, S2, S3, S4, and S5 basically follows the above scheme. Steps S6-S9 can be adjusted, and partial assembly can be performed between, before, or after steps S1-S5, depending on the actual situation.

[0052] In this assembly method, the assembly precision of the screw rotor components is higher and the assembly and debugging difficulty is lower (ensuring higher adjustment precision of the gap value between the two screw rotor components and the gap value between the screw rotor components and the screw pump body cavity, and lower debugging difficulty), thereby effectively ensuring the vacuum degree of the vacuum pump, facilitating subsequent maintenance and cleaning, reducing the maintenance rate, and extending the service life.

[0053] In the description of this utility model, it should be understood that the terms "upper," "lower," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship 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. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.

[0054] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; 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. For instance, the two components can be mechanically connected by abutting or contacting each other; they can also be directly hung or connected by an intermediate medium; or they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

Claims

1. A vacuum pump, comprising: The pump body has an independent Roots pump body cavity and a screw pump body cavity. The pump body also has a connecting air passage that connects the Roots pump body cavity and the screw pump body cavity. The pump body is respectively provided with an air inlet that communicates with the Roots pump body cavity and an air outlet that communicates with the screw pump body cavity. The rotor assembly comprises two sets of intermeshing rotor components. Each rotor assembly includes a connecting shaft, a Roots rotor component mounted on the connecting shaft, and a screw rotor component. The screw rotor component and the Roots rotor component are both disposed within the cavity of the screw pump body. The two ends of the connecting shaft are rotatably connected to the two ends of the pump body. The characteristic feature is that: The pump body includes a screw pump body and a roots pump body connected to each other, wherein the screw pump body cavity is disposed within the screw pump body and the roots pump body cavity is disposed within the roots pump body; The screw rotor assembly and the connecting shaft are an integral structure, and the Roots rotor assembly is detachably mounted on the connecting shaft; The outer wall of the screw pump body is provided with a through cavity communicating with the screw pump body cavity. The through cavity is positioned directly opposite the two sets of screw rotor components. A sealing component that seals the through cavity is detachably installed on the screw pump body.

2. The vacuum pump according to claim 1, characterized in that: The end of the connecting air passage is provided with at least one connecting air passage outlet communicating with the screw pump body cavity. The connecting air passage outlet is located on the end face of the Roots pump body facing the screw pump body cavity, and the connecting air passage outlet is arranged parallel to the axis of the connecting shaft.

3. The vacuum pump according to claim 2, characterized in that: There are two connecting air passage outlets, and two connecting shafts are arranged between the two connecting air passage outlets. Each connecting air passage outlet is respectively arranged facing a set of screw rotor components. And / or, the connecting air passage outlet is positioned directly opposite the edge of the corresponding screw rotor component.

4. The vacuum pump according to claim 1, characterized in that: The inner surface of the sealing component is flush with the inner surface of the screw pump body cavity; And / or, the blocking component includes a blocking block and a connecting block disposed at one end of the blocking block, the blocking block being adapted to the through cavity, the blocking block being inserted into the through cavity, the connecting block being disposed outside the through cavity, and the connecting block being connected to the screw pump body via fasteners.

5. The vacuum pump according to claim 1, characterized in that: The outer wall of the screw pump body is also provided with a pressure relief channel communicating with the screw pump body cavity, and a one-way valve is provided in the pressure relief channel; And / or, the pressure relief channel is located close to the Roots pump body.

6. The vacuum pump according to claim 5, characterized in that: The through cavity is located at the bottom of the screw pump body, and the pressure relief channel is located at the top of the screw pump body; And / or, the one-way valve is a float valve.

7. The vacuum pump according to claim 1, characterized in that: The Roots rotor assembly includes a first-stage Roots rotor assembly, a second-stage Roots rotor assembly, and an intermediate assembly, all of which are integrally formed. The intermediate assembly connects the first-stage and second-stage Roots rotor assemblies. The Roots pump body includes a first-stage pump body and a second-stage pump body that are interconnected. The second-stage pump body is disposed between the first-stage pump body and the screw pump body. The Roots pump body cavity includes a first-stage Roots pump body cavity and a second-stage Roots pump body cavity. The first-stage Roots pump body cavity is disposed within the first-stage pump body, and the second-stage Roots pump body cavity is disposed within the second-stage pump body. The first-stage Roots rotor assembly is disposed within the first-stage Roots pump body cavity, and the second-stage Roots rotor assembly is disposed within the second-stage Roots pump body cavity. A partition is also provided between the first-stage pump body and the second-stage pump body. The partition is disposed inside the pump body and has through holes that cooperate with the intermediate component.

8. The vacuum pump according to claim 7, characterized in that: The Roots pump body is provided with an intermediate air passage connecting the primary Roots pump body cavity and the secondary Roots pump body cavity; The air inlet is connected to the top of the first-stage Roots pump body cavity; The intermediate air passage includes a primary intermediate air passage and a secondary intermediate air passage. The primary intermediate air passage is disposed within the primary pump body, with its inlet connected to the bottom of the primary Roots pump body cavity and its outlet connected to the end face of the primary pump body facing the secondary pump body. The secondary intermediate air passage is disposed within the secondary pump body outside the secondary Roots pump body cavity, with its inlet facing the primary pump body and connected to the outlet of the primary intermediate air passage. The outlet of the secondary intermediate air passage is connected to the top of the secondary Roots pump body cavity. The connecting air passage is located inside the secondary pump body, and the inlet of the connecting air passage is connected to the bottom of the secondary Roots pump body cavity.

9. The vacuum pump according to claim 7, characterized in that: A sealing element is provided at the connection between the screw pump body and the secondary Roots pump body, and a sealing element is also provided at the connection between the primary pump body and the secondary pump body; And / or, the partition is disposed inside the seal between the primary pump body and the secondary pump body.

10. The vacuum pump according to claim 1, characterized in that: The Roots rotor assembly has a mounting hole, and the two ends of the mounting hole are respectively connected to the two ends of the Roots rotor assembly in the axial direction. The Roots rotor assembly is mounted on the corresponding coupling shaft through the mounting hole. The inner surface of the mounting hole is provided with a first positioning element, and the connecting shaft is provided with a second positioning element that cooperates with the first positioning element. The first positioning element and the second positioning element restrict the rotation of the Roots rotor component relative to the connecting shaft.

11. The vacuum pump according to claim 1, characterized in that: The two connecting shafts are arranged parallel to each other, the two screw rotor components arranged in the screw pump body cavity mesh with each other, and the two Roots rotor components arranged in the Roots pump body cavity mesh with each other.

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