Method for machining a vacuum pump housing and vacuum pump

Abstract

The application discloses a machining method of a vacuum pump shell and a vacuum pump, and belongs to the technical field of vacuum pump manufacturing. The machining method of the vacuum pump shell comprises the following steps: providing a plurality of blank parts; assembling the plurality of blank parts together to form a shell pre-assembly; uniformly processing the shell pre-assembly to form key positions; disassembling the shell pre-assembly, and then finely processing each independent blank part to obtain a plurality of sub-shells; and assembling the plurality of sub-shells together to obtain the vacuum pump shell. When the key positions of the vacuum pump shell are machined, the blank parts are temporarily assembled and fixed to form a whole, and then the key positions of the vacuum pump shell are uniformly processed based on the whole structure. Compared with the mode of separately machining the key positions on a single blank part, the machining method can reduce the cumulative error during the assembly of the sub-shells, and improve the machining and installation precision of the whole vacuum pump shell.

Description

Technical Field

[0001] This application relates to the field of vacuum pump manufacturing technology, specifically to a method for processing a vacuum pump housing and a vacuum pump. Background Technology

[0002] The vacuum pump housing, also known as the vacuum pump stator or stator shell, is typically formed by two parts joined together through sealing surfaces. The vacuum pump stator and rotor components work together to form the vacuum pump chamber; the rotation of the rotor components drives gas flow, thereby achieving the vacuuming function. The manufacturing precision of the Roots vacuum pump housing largely determines the ultimate vacuum level and reliability of the vacuum pump.

[0003] In related technologies, the vacuum pump housing is formed by assembling multiple components. During the manufacturing process, each component is individually machined and then assembled into a single unit. This manufacturing method easily leads to the accumulation of machining errors in each component, resulting in large cumulative errors. This can cause rotor eccentricity or excessively large or uneven internal clearances in the vacuum pump, leading to problems such as high operating noise, rotor wear, and even vacuum pump seizure, resulting in unstable vacuum levels and gas leaks. Summary of the Invention

[0004] This application provides a method for processing a vacuum pump housing and a vacuum pump, aiming to solve the technical problem of large cumulative errors in the manufacturing process of vacuum pump housings.

[0005] In a first aspect, this application provides a method for processing a vacuum pump housing, comprising the following steps: Multiple blank parts are available; The multiple blank parts are assembled together to form a pre-assembled shell; The pre-assembled shell is uniformly processed to form key parts; The pre-assembled shell is disassembled and reassembled, and each individual blank is then finely finished to obtain multiple sub-shells; The multiple sub-shells are assembled together to obtain the vacuum pump housing.

[0006] In some of these design approaches, the method of manufacturing the vacuum pump housing further includes pre-processing each individual blank before forming the housing pre-assembly.

[0007] In some of these design approaches, the blank is a metal part, and the pretreatment includes annealing the metal part.

[0008] In some of these design approaches, prior to the uniform processing, the gap between the mating surfaces of two adjacent blanks in the pre-assembled housing is ≤0.05mm.

[0009] In some design approaches, the process of uniformly machining the pre-assembled housing to form key parts includes machining a reference surface on the pre-assembled housing, and using the reference surface as a positioning reference, machining the pre-assembled housing as a whole to form the key parts.

[0010] In some of these design approaches, one end face of the pre-assembled housing is milled to form the reference surface, wherein the flatness of the reference surface is ≤0.02mm / m and the surface roughness Ra is ≤3.2μm.

[0011] In some of these designs, the critical component includes a pump chamber located within the housing pre-assembly, wherein the pump chamber has a cylindricity ≤ 0.01 mm, an axial coaxiality ≤ 0.015 mm, and a surface roughness Ra ≤ 3.2 μm on the wall of the pump chamber.

[0012] In some of these designs, the surface roughness Ra of the mating surface between the pump chamber wall and the rotor is ≤1.6μm.

[0013] In some of these designs, the key component includes a sealing groove located on the mating surface of the blank, the symmetry of the sealing groove relative to the centerline of the pump cavity being ≤0.03mm.

[0014] In some of these design approaches, the key components include the mating surfaces of two adjacent blanks in the pre-assembled housing, wherein the flatness of the mating surfaces is ≤0.015mm, the surface roughness Ra is ≤1.6μm, and the perpendicularity of the mating surfaces to the reference surface is ≤0.02mm, and the reference surface is the end face of the pre-assembled housing.

[0015] In some of these designs, the key component includes a hole.

[0016] In some of these designs, the holes include multiple sets of bearing holes with a coaxiality of ≤0.01 mm.

[0017] In some of these designs, the critical component includes a sealing surface with a flatness ≤0.02mm and a surface roughness Ra ≤1.6μm.

[0018] In some of these design approaches, the same set of preset machining parameters are used to process the critical parts, including holes and sealing surfaces.

[0019] In some of these design approaches, the finishing process includes at least one of deburring and chamfering.

[0020] In some of these designs, there are two blanks, namely the upper stator housing blank and the lower stator housing blank of the vacuum pump. The processing method for the vacuum pump housing includes: Provide upper stator housing blank and lower stator housing blank; The upper stator housing blank and the lower stator housing blank are assembled together to form a pre-assembled housing assembly; One end face of the pre-assembled shell is machined into a reference surface; Using the reference plane as the positioning reference, a mating surface, a pump cavity, a bearing hole, a flange hole, and a sealing surface are machined on the housing pre-assembly; wherein, the same machining parameters are used for machining the bearing hole, the flange hole, and the sealing surface; The pre-assembled housing is disassembled and reassembled, and then the upper stator housing blank and the lower stator housing blank are respectively finely finished to obtain the upper stator housing and the lower stator housing; The upper stator housing and the lower stator housing are assembled together to obtain the vacuum pump housing.

[0021] Secondly, this application also provides a vacuum pump, the vacuum pump comprising a vacuum pump housing processed by the processing method of the vacuum pump housing described in the first aspect.

[0022] The vacuum pump housing processing method provided in this application embodiment first temporarily assembles and fixes each blank part into a whole when processing the key parts of the vacuum pump housing, and then performs unified processing of the key parts of the vacuum pump housing based on the overall structure. Compared with processing the key parts separately on a single blank part, this can reduce the cumulative error during the assembly of the sub-housing and improve the overall processing and installation accuracy of the vacuum pump housing. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a schematic flowchart of a method for processing a vacuum pump housing according to an exemplary embodiment of this disclosure; Figure 2 This is an exploded structural diagram of a vacuum pump housing provided in an exemplary embodiment of this disclosure. Detailed Implementation

[0025] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0026] In the description of this application, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are used only for the convenience of describing this application 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 application. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of the stated features. In the description of this application, "a plurality of" means two or more, unless otherwise explicitly specified.

[0027] "A and / or B" includes the following three combinations: A only, B only, and a combination of A and B.

[0028] The use of "applies to" or "configured to" in this application implies open and inclusive language, which does not exclude the applicability to or configuration to devices performing additional tasks or steps. Additionally, the use of "based on" implies openness and inclusivity, because processes, steps, calculations, or other actions "based on" one or more of the stated conditions or values ​​may in practice be based on additional conditions or values ​​beyond those stated.

[0029] In this application, the term "exemplary" is used to mean "used as an example, illustration, or description." Any embodiment described as "exemplary" in this application is not necessarily to be construed as being more preferred or advantageous than other embodiments. The following description is provided to enable any person skilled in the art to make and use this application. Details are set forth in the following description for purposes of explanation. It should be understood that those skilled in the art will recognize that this application can be made without using these specific details. In other instances, well-known structures and processes are not described in detail to avoid obscuring the description of this application with unnecessary detail. Therefore, this application is not intended to be limited to the embodiments shown, but is consistent with the broadest scope of the principles and features disclosed in this application.

[0030] Firstly, this embodiment provides a method for processing a vacuum pump housing, such as... Figure 1 As shown, the machining method for the vacuum pump housing includes the following steps: S1. Provide multiple blank parts; S2. Assemble multiple blank parts together to form a pre-assembled shell; S3. Perform unified processing on the pre-assembled shell to form key parts; S4. Disassemble and reassemble the pre-assembled shell, and then perform fine finishing on each individual blank to obtain multiple sub-shells; S5. Assemble multiple sub-shells together to obtain the vacuum pump housing.

[0031] In the above-described processing method for the vacuum pump housing, the blank part is processed multiple times to form a sub-housing, and multiple sub-housings are assembled together to form the vacuum pump housing. Optionally, before forming the housing pre-assembly, the processing method for the vacuum pump housing also includes pre-processing each individual blank part. Thus, the processing of the blank part is divided into the following stages: first, each individual blank part is pre-processed; then, based on the assembly of the blank parts to form a whole (i.e., the housing pre-assembly), the blank parts are further processed; then, the integrated blank parts are disassembled, and each individual blank part is precision-machined again. The precision-machined blank part becomes a sub-housing. Typically, the shape, size, structure, and hardness of the blank part will change at different processing stages.

[0032] The vacuum pump housing is formed by assembling multiple sub-housings together. "Multiple" here refers to two or more sub-housings. See also... Figure 2 The following explanation uses the example of a vacuum pump housing 10 being assembled from two sub-housing units (the upper stator housing 1 and the lower stator housing 2) as an example.

[0033] In a specific example, before preprocessing, the blanks are in block form, i.e., they are bulk materials. The two block-shaped blanks are preprocessed separately, for example, by turning or milling, to give them the basic outline of a sub-shell. During preprocessing, the two blanks are in a separate state. The two preprocessed blanks are temporarily assembled together, for example, by using a pre-assembly fixture to fix them as a whole, thus obtaining a shell pre-assembly, which has the basic outline of a vacuum pump shell. The shell pre-assembly undergoes unified processing, i.e., based on the state where the two blanks are fixed as a whole, the two blanks are processed simultaneously, including but not limited to milling, boring, and drilling. During this process, the key parts of the vacuum pump shell are further fabricated on the shell pre-assembly, which already has the basic outline of the vacuum pump shell. These key parts refer to areas on the vacuum pump shell that have a significant impact on the performance of the vacuum pump, including but not limited to at least one of holes, surfaces, grooves, and cavities. After this unified processing, the blanks possess more features, including the key parts, and their structure becomes more closely similar to the sub-shell. The pre-assembled housing, after undergoing standardized processing, is then disassembled. The two blanks are separated again, and each blank is precision-machined, including but not limited to deburring and chamfering. After precision machining, the blanks form sub-housings. The two sub-housings are then assembled together to obtain the vacuum pump housing.

[0034] In summary, the vacuum pump housing processing method provided in this application first temporarily assembles and fixes each blank into a whole when processing the key parts of the vacuum pump housing, and then performs unified processing of the key parts of the vacuum pump housing based on the overall structure. Compared with processing the key parts separately on a single blank, this can reduce the cumulative error during the assembly of the sub-housing and improve the overall processing and installation accuracy of the vacuum pump housing.

[0035] Meanwhile, the processing method of the vacuum pump housing, through the above-mentioned box-fitting processing, can also ensure that each blank part maintains a consistent deformation trend under stress, avoiding stress concentration caused by assembly after individual processing, thereby enhancing the overall reliability of the vacuum pump housing structure.

[0036] The vacuum pump housing processing method provided in this application embodiment can achieve coaxiality of key parts such as pump cavity and bearing hole ≤0.01mm and flatness of mating surface ≤0.015mm. Therefore, it can be applied to the processing of high-precision vacuum pumps (such as dry vacuum pumps for semiconductors, high vacuum diffusion pumps, etc.). At the same time, the vacuum pump housing processing method can also be used to manufacture vacuum pump housings with complex structures (such as multi-cavity, irregular flanges, etc.), which can effectively overcome the problem that traditional single-part processing and assembly can easily lead to excessive form and position tolerances.

[0037] In some embodiments of this application, the blank is a metal part, and the pretreatment includes annealing the metal part. Annealing the metal blank can eliminate the casting stress of the blank. Before and after annealing, the structure and contour of the blank do not change significantly; rather, the composition or physical properties of the material, such as hardness, will change.

[0038] Since the blank parts require further overall assembly and finishing after pretreatment to form the sub-shell, and some material is consumed during these processes, a certain machining allowance is usually reserved for the pre-assembled shell after pretreatment. For example, the machining allowance on one side of the mating surface of the blank part is 3mm~5mm, and the machining allowance of the pump cavity is 2mm~3mm.

[0039] In some embodiments of this application, multiple blank parts can be assembled together using temporary assembly fixtures (e.g., pre-assembly fixtures). As an example, the pre-assembly fixture includes a clamping device and a locating pin, which secure the upper and lower sub-shells as a whole.

[0040] In some embodiments of this application, before unified processing, the gap between the mating surfaces of two adjacent blanks in the housing pre-assembly is ≤0.05mm. Reducing the assembly gap helps to improve the sealing performance of the vacuum pump housing. It should be noted that the mating surface of the blanks refers to the surface where the blank contacts or engages with another adjacent blank when the blanks are assembled into the housing pre-assembly. The gap between the mating surfaces of two adjacent blanks can be detected using a feeler gauge.

[0041] In some embodiments of this application, the unified processing of the shell pre-assembly to form key parts includes machining a reference surface on the shell pre-assembly, and using the reference surface as a positioning reference, machining the shell pre-assembly as a whole to form key parts.

[0042] In other words, when machining the key parts that form the vacuum pump housing, the entire process is based on the pre-fixation of each blank part in a box and on a unified positioning datum. This avoids the datum misalignment errors of traditional step-by-step machining, thereby reducing error accumulation. Furthermore, this "box-fixed, unified datum, and overall machining" approach, which processes key parts of each blank part based on a unified datum, significantly improves the core precision of the vacuum pump housing, such as coaxiality, flatness, and parallelism, making it particularly suitable for high-vacuum, high-precision equipment.

[0043] In some embodiments of this application, one end face of the housing pre-assembly is milled to form a reference surface, the flatness of the reference surface being ≤0.02mm / m and the surface roughness Ra being ≤3.2μm.

[0044] By machining the end face of the pre-assembled housing into a reference surface, it is possible to take into account the machining of multiple different key parts. Furthermore, by controlling the flatness and surface roughness of the reference surface, it is possible to further reduce the machining error of key parts, thereby reducing the cumulative error.

[0045] The housing pre-assembly typically has two opposing ends, with one end face designated as the top surface and the other end face as the bottom surface. In a specific example, the bottom surface of the housing pre-assembly is machined as a reference surface. Specifically, the housing pre-assembly is clamped on a CNC machining center, and rough milling is performed using the bottom surface as a reference, leaving a 2mm machining allowance. Simultaneously, the two side locating surfaces of the housing pre-assembly are rough milled to ensure the perpendicularity between the locating surfaces and the bottom surface is ≤0.1mm. The bottom surface is then finish milled to a flatness ≤0.02mm / m and a surface roughness Ra ≤3.2μm. This bottom surface serves as the unified reference for subsequent machining, i.e., the reference surface. Of course, in other examples, the top surface can also be machined as the reference surface. In other embodiments, other surfaces on the housing pre-assembly, such as the outer surface, can also be machined as reference surfaces; this is not limited here.

[0046] In some embodiments of this application, the key component includes a pump chamber located within the housing pre-assembly, wherein the cylindricity of the pump chamber is ≤0.01mm, the coaxiality of the pump chamber along the axial direction is ≤0.015mm, and the surface roughness Ra of the pump chamber wall is ≤3.2μm.

[0047] The pump chamber within the pre-assembled housing is also known as the pump cavity inside the vacuum pump housing. The pump chamber is the part of the vacuum pump used to achieve gas intake, compression, and exhaust; it houses the moving parts of the vacuum pump, such as the rotor and blades.

[0048] In traditional processes, the coaxiality error of the pump cavity is about 0.03mm, while in this process, the coaxiality of the pump cavity can be controlled within 0.01mm, or even within 0.006mm.

[0049] In a specific example, the overall machining process of the pump cavity includes: using the boring function of a CNC machining center, the integral cavity formed by assembling the various blanks is sequentially rough-bored, semi-finish-bored, and finish-bored from the top of the pre-assembled housing, completing the coaxial machining of the pump cavity in one setup. After rough boring, a machining allowance of 1mm is reserved, the cutting speed is 80m / min, and the feed rate is 0.3mm / r; finish boring is performed to the dimensions of the pump cavity as shown in the drawing, controlling the cylindricity of the pump cavity to be ≤0.01mm, the coaxiality of the pump cavity along the axial direction to be ≤0.015mm, and the surface roughness Ra of the pump cavity wall to be ≤3.2μm.

[0050] In some embodiments of this application, the surface roughness Ra of the mating surface between the pump chamber wall and the rotor is ≤1.6μm. Compared to other locations on the pump chamber wall, the surface roughness of the mating surface between the pump chamber wall and the rotor is lower, which helps to reduce wear and improve the rotational efficiency of the rotor.

[0051] In some embodiments of this application, key components include a sealing groove located on the mating surface of the blank, with the symmetry of the sealing groove relative to the centerline of the pump cavity ≤ 0.03 mm. The sealing groove on the mating surface of the blank is also the sealing groove on the mating surface of the sub-shells. When multiple sub-shells are assembled together to form a vacuum pump housing, adjacent sub-shells contact each other through the mating surface. Due to the influence of process precision, gaps inevitably exist between the mating surfaces of different sub-shells, thus affecting the sealing effect of the pump cavity. By setting a sealing groove on the mating surface, and further setting a sealing element within the sealing groove, the sealing groove restricts the position of the sealing element, preventing arbitrary movement of the sealing element. The sealing element seals the gaps between the mating surfaces of different sub-shells, improving the sealing effect of the pump cavity. The dimensional and positional accuracy of the sealing groove on the mating surface will, to some extent, affect its limiting effect on the sealing element, and thus affect the sealing effect of the pump cavity. By controlling the symmetry of the sealing groove relative to the pump cavity, the dimensional and positional accuracy of the sealing groove can be ensured. As an example, the sealing groove is a rectangular groove or an O-ring groove.

[0052] In some embodiments of this application, key components include the mating surfaces of two adjacent blanks in the pre-assembled housing. The flatness of the mating surfaces is ≤0.015mm, the surface roughness Ra is ≤1.6μm, and the perpendicularity of the mating surfaces to the reference surface is ≤0.02mm. The reference surface is the end face of the pre-assembled housing. The mating surfaces obtained by the "box-fitting, unified reference, and overall machining" method have higher flatness and smaller clearances. This helps to reduce the risk of leakage caused by uneven compression of the seals between the mating surfaces and optimizes the sealing performance of the pump cavity.

[0053] In a specific example, a CNC machining center is used to rough-mill the mating surfaces of each blank from the top of the pre-assembled housing in one pass, leaving a machining allowance of 1.5mm. The cutting speed is 100m / min~120m / min, and the feed rate is 0.2mm / r, ensuring that the mating surfaces of two adjacent blanks are in the same plane. A high-precision face milling cutter is used for two passes (one for rough milling with a machining allowance of 0.3mm, and one for finish milling), controlling the flatness of the mating surfaces to ≤0.015mm and the surface roughness Ra≤1.6μm, while ensuring that the perpendicularity of the mating surfaces to the reference surface is ≤0.02mm. During finish milling of the mating surfaces, the cutting speed is reduced to 80m / min~100m / min, and the feed rate is 0.1mm / r~0.15mm / r to prevent tool wear from causing flatness deviations.

[0054] In some embodiments of this application, key components include holes. Optionally, the holes include at least one of bearing holes, locating pin holes, bolt holes, flange holes, and oil holes. When multiple types of holes are included, different types of holes (e.g., locating pin holes and bearing holes) can be machined simultaneously, eliminating the need for repeated adjustments during assembly, shortening assembly time, and improving assembly efficiency.

[0055] In a specific example, a CNC machining center is used, with the reference surface of the housing pre-assembly as the positioning point, to drill, ream, rough bore, and finish bore the housing pre-assembly, thereby forming bearing holes on the housing pre-assembly. Multiple sets of bearing holes are machined on the housing pre-assembly, ensuring that the coaxiality of the multiple sets of bearing holes is ≤0.01mm; simultaneously, the perpendicularity of the bearing holes to the mating surface is ≤0.02mm. As an example, the multiple sets of bearing holes include motor end bearing holes and pump end bearing holes.

[0056] In a specific example, CNC machining centers are used to perform drilling and reaming processes to machine locating pin holes on the pre-assembled housing. The hole accuracy of the locating pin holes is H7 to ensure the positioning accuracy when the blanks are separated and reassembled.

[0057] In a specific example, a CNC machining center is used to machine bolt holes according to coordinates. The bottom diameter of the bolt hole needs to be 0.5mm~1mm smaller than the nominal diameter of the thread, and the tapping accuracy is 6H / 6g to prevent stripping during assembly.

[0058] In one specific example, a CNC machining center is used to drill oil holes on the housing pre-assembly, and the openings of the oil holes are chamfered.

[0059] In some embodiments of this application, key components include sealing surfaces, which have a flatness ≤0.02mm and a surface roughness Ra ≤1.6μm. As an example, the sealing surface includes at least one of an inlet flange surface, an outlet flange surface, and an oil port flange surface.

[0060] In some embodiments of this application, when critical parts include holes and sealing surfaces, the same set of preset machining parameters are used for machining. The reason for "poor consistency and large cumulative errors" in traditional single-part machining followed by assembly lies in individual machining differences. These individual machining differences stem from both different machining datums and inconsistent machining parameters. Therefore, using the same preset machining parameters for critical parts, including holes and sealing surfaces, can improve the consistency of the machining process and reduce errors. Furthermore, the machining parameters are automatically called by the CNC system. By combining "unified machining parameters" with "CNC automation control," deviations caused by manual operation or individual machining differences are eliminated, thereby improving product consistency. Optionally, the machining parameters include, but are not limited to, at least one of cutting speed, feed rate, and toolpath.

[0061] In the embodiments of the present application, through the process of "box combination pre-fixation + unified reference + overall machining", the key parts of each blank are generated based on the same reference, avoiding the reference non-coincidence error in traditional step-by-step machining, eliminating error accumulation from the source, and the coaxiality of the bearing holes can be controlled within 0.03 mm. At the same time, further through the automatic control of unified machining parameters, the machining accuracy of different blanks is ensured to be consistent, and the consistency of the performance such as the air leakage volume and pumping efficiency of the obtained products is improved by more than 30%. No subsequent fitting is required, reducing the production cost.

[0062] In some embodiments of the present application, when using a pre-assembly fixture including a pressing device and a positioning pin for box combination, when disassembling and assembling the housing pre-assembly, loosen the pressing device, pull out the positioning pin, separate each blank, and check whether there are indentations or deformations on the joint surface of the blank. If slight deformation (≤0.02 mm) is found on the joint surface of the blank after each blank is separated, it can be corrected by manually grinding with abrasive paste to avoid secondary clamping and machining.

[0063] In some embodiments of the present application, the fine finishing treatment includes at least one of deburring and chamfering treatment. After each blank is separated, the non-fitting edges of each blank are separately deburred and chamfered to prevent the sub-housing from scratching the seal during assembly. After each blank is separated, the threaded holes on the flange surface are finely finished to remove the iron filings in the threaded holes.

[0064] In some embodiments of the present application, before assembling multiple sub-housings into a vacuum pump housing, first pre-assemble the multiple sub-housings to obtain an initial assembly, and detect the initial assembly. Optionally, use a feeler gauge to detect the fit degree of the joint surface of the sub-housing, use a dial indicator to detect the coaxiality of the pump cavity and the bearing holes, and conduct a pressure test on the initial assembly. The test method is to fill 0.6 MPa compressed air into the pump cavity, keep the pressure for 1 hour, and apply soap water at the joint surface and the hole opening. If there is no air bubble leakage, it is qualified. Optionally, use the initial assembly for a test run: install the rotor assembly in the pump cavity, rotate the rotor assembly, and the rotor assembly runs smoothly without jamming. The noise during the no-load operation of the motor is ≤75 dB(A).

[0065] In some embodiments of the present application, the machining method of the vacuum pump housing further includes multi-dimensional detection of the vacuum pump housing after assembling multiple sub-housings into the vacuum pump housing. The multi-dimensional detection includes at least two of the following aspects: joint surface flatness detection, pump cavity coaxiality detection, coaxiality detection of the bearing hole group, sealing performance test, and pump cavity surface roughness detection.

[0066] As an example, use a straightedge in combination with a feeler gauge, or use a coordinate measuring machine to detect the joint surface flatness. The requirement for the joint surface flatness is extremely high, and the flatness error within every 100 mm length range needs to be controlled within 0.015 mm.

[0067] As an example, the coaxiality of the pump cavity can be checked by installing a mandrel and using a dial indicator, or directly by using a coordinate measuring machine. The coaxiality error of the pump cavity must not exceed 0.015 mm over its entire length.

[0068] As an example, the coaxiality of the bearing bore assembly can be checked using boring bar displacement detection or coordinate measuring machine (CMM). The error between adjacent bearing bores must be ≤0.01mm.

[0069] As an example, the sealing test is conducted under a pressure of 0.6 MPa. After applying soapy water to the mating surfaces and openings of the enclosure, no air bubbles are allowed to leak.

[0070] As an example, the surface roughness of the pump cavity is tested using a roughness tester, and the requirement is that the surface roughness Ra of the pump cavity is ≤1.6μm.

[0071] In some embodiments of this application, there are two blanks, namely an upper stator housing blank and a lower stator housing blank for the vacuum pump. The blanks are processed multiple times to form two sub-housings, namely an upper housing and a lower housing. That is, the vacuum pump housing is formed by assembling the upper housing and the lower housing.

[0072] Specifically, please see Figure 1 The processing method of the vacuum pump housing 10 includes: S1. Provide upper stator shell blank and lower stator shell blank; S2. The upper stator shell blank and the lower stator shell blank are assembled together to form a shell pre-assembly; S3. Machining one end face of the pre-assembled housing into a reference surface 101; using the reference surface 101 as a positioning reference, machining a mating surface 102, a pump cavity 103, a bearing hole, a flange hole, and a sealing surface on the pre-assembled housing; wherein, the same machining parameters are used for machining the bearing hole, the flange hole, and the sealing surface. S4. Disassemble and reassemble the pre-assembled housing, and then perform fine finishing on the upper stator housing blank and the lower stator housing blank respectively to obtain the upper stator housing 1 and the lower stator housing 2. S5. Assemble the upper stator housing 1 and the lower stator housing 2 together to obtain the vacuum pump housing 10.

[0073] In some specific implementations, step S3 specifically includes: The mating surfaces (i.e., both sides) of the upper and lower stator housing blanks are milled in one pass from the top of the pre-assembled housing, leaving a 1.5mm allowance. The cutting speed is 100m / min~120m / min, and the feed rate is 0.2mm / r, ensuring that the mating surfaces of the upper and lower stator housing blanks are in the same plane. A high-precision face milling cutter is then used to machine the mating surfaces in two passes (one rough milling leaving 0.3mm, and one finish milling), controlling the flatness of the mating surfaces to ≤0.015mm and the surface roughness Ra ≤1.6μm, while ensuring that the perpendicularity of the mating surfaces to the bottom surface (which serves as the reference surface) is ≤0.02mm.

[0074] Using the boring function of a CNC machining center, the pump cavity (the integral cavity formed by the combination of the upper stator housing blank and the lower stator housing blank) is sequentially rough-bored, semi-finish-bored, and finish-bored from the top of the housing pre-assembly, completing the coaxial machining of the pump cavity in the upper and lower stator housing blanks in one setup. During rough boring, a 1mm allowance is left, the cutting speed is 80m / min, and the feed rate is 0.3mm / r. During finish boring to the drawing dimensions, the cylindricity of the pump cavity is controlled to be ≤0.01mm, the axial coaxiality of the pump cavity is ≤0.015mm, and the surface roughness Ra of the inner wall of the pump cavity is ≤3.2μm.

[0075] Using a CNC machining center and with the reference surface of the pre-assembled housing as the positioning, the bearing holes (the hole group after the combination of the upper stator housing blank and the lower stator housing blank) are drilled, enlarged, rough bored, and fine bored to ensure that the coaxiality of multiple sets of bearing holes is ≤0.01mm (such as the bearing holes at the motor end and the pump end), the hole tolerance is controlled at K6, and the perpendicularity to the mating surface is ≤0.02mm.

[0076] Using a CNC machining center, the sealing surface is precision milled on the pre-assembled housing to ensure that the flatness of the sealing surface is ≤0.02mm and the roughness Ra is ≤1.6μm.

[0077] The flange holes are machined using a CNC machining center with the reference surface of the pre-assembled shell as the positioning point.

[0078] The same set of preset machining parameters (such as cutting speed, feed rate, and tool path) are used for machining bearing holes, sealing surfaces, and flange holes, and the machining parameters are automatically called by the CNC system to ensure that the machining process of different vacuum pump housings is consistent.

[0079] In some specific implementations, step S3 further includes: The positioning pin holes (penetrating the upper and lower stator housing blanks) are machined using a CNC machining center through drilling and reaming processes. The accuracy of the positioning pin holes is H7, ensuring the positioning accuracy when the upper and lower stator housing blanks are separated and reassembled.

[0080] Using a CNC machining center, bolt holes are machined according to coordinates. The diameter of the bottom hole should be 0.5mm~1mm smaller than the nominal diameter of the thread, and the tapping accuracy should be 6H / 6g to prevent stripping during assembly.

[0081] A CNC machining center is used to machine the sealing groove (such as a rectangular groove or an O-ring groove) on the mating surface to ensure the dimensional and positional accuracy of the sealing groove (symmetry relative to the centerline of the pump cavity ≤ 0.03mm).

[0082] In some embodiments of this application, the number of blanks may be two or more. As an example, when the rotor is a multi-stage split rotor, it can be assembled first and then processed, in which case the number of blanks is at least four; as another example, the blanks may include the stator and the bearing end plates at both ends of the stator, which can be pre-assembled and then processed, in which case the number of blanks is at least three.

[0083] In some embodiments of this application, the vacuum pump is a Roots vacuum pump, and the vacuum pump housing is the housing of a Roots vacuum pump.

[0084] Secondly, embodiments of this application also provide a vacuum pump, which includes a vacuum pump housing processed according to the vacuum pump housing processing method provided in the first aspect.

[0085] A typical vacuum pump includes a rotor, which is housed within the pump chamber of the vacuum pump casing.

[0086] In some embodiments of this application, the vacuum pump includes at least one of a dry vacuum pump and a high vacuum diffusion pump.

[0087] In some embodiments of this application, the vacuum pump is a Roots vacuum pump.

[0088] The above provides a detailed description of a vacuum pump housing processing method and a vacuum pump provided in the embodiments of this application. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A method for processing a vacuum pump housing, characterized in that, Includes the following steps: Multiple blank parts are available; The multiple blank parts are assembled together to form a pre-assembled shell; The pre-assembled shell is uniformly processed to form key parts; The pre-assembled shell is disassembled and reassembled, and each individual blank is then finely finished to obtain multiple sub-shells; The multiple sub-shells are assembled together to obtain the vacuum pump housing.

2. The method for processing the vacuum pump housing according to claim 1, characterized in that, The processing method of the vacuum pump housing further includes pre-processing each individual blank before forming the housing pre-assembly.

3. The method for processing the vacuum pump housing according to claim 2, characterized in that, The blank is a metal part, and the pretreatment includes annealing the metal part.

4. The method for processing the vacuum pump housing according to claim 1, characterized in that, Before the unified processing, the gap between the mating surfaces of two adjacent blanks in the pre-assembled housing is ≤0.05mm.

5. The method for processing the vacuum pump housing according to claim 1, characterized in that, The process of uniformly processing the pre-assembled shell to form key parts includes machining a reference surface on the pre-assembled shell, and using the reference surface as a positioning reference, machining the pre-assembled shell as a whole to form the key parts.

6. The method for processing the vacuum pump housing according to claim 5, characterized in that, One end face of the pre-assembled housing is milled to form the reference surface, wherein the flatness of the reference surface is ≤0.02mm / m and the surface roughness Ra is ≤3.2μm.

7. The method for processing the vacuum pump housing according to claim 5, characterized in that, The key component includes a pump chamber located within the pre-assembled housing. The cylindricity of the pump chamber is ≤0.01mm, the coaxiality of the pump chamber along the axial direction is ≤0.015mm, and the surface roughness Ra of the pump chamber wall is ≤3.2μm.

8. The method for processing the vacuum pump housing according to claim 7, characterized in that, The surface roughness Ra of the mating surface between the pump chamber wall and the rotor is ≤1.6μm; and / or, The key component includes a sealing groove located on the mating surface of the blank, wherein the symmetry of the sealing groove relative to the center line of the pump cavity is ≤0.03mm.

9. The method for processing the vacuum pump housing according to claim 5, characterized in that, The key components include the mating surfaces of two adjacent blanks in the pre-assembled housing, wherein the flatness of the mating surfaces is ≤0.015mm, the surface roughness Ra is ≤1.6μm, and the perpendicularity of the mating surfaces to the reference surface is ≤0.02mm, and the reference surface is the end face of the pre-assembled housing; and / or, The key components include holes, optionally including multiple sets of bearing holes with a coaxiality ≤0.01mm; and / or, The key components include a sealing surface, wherein the flatness of the sealing surface is ≤0.02mm and the surface roughness Ra is ≤1.6μm; and / or, When the key parts include holes and sealing surfaces, the same set of preset processing parameters are used for processing.

10. A method for processing a vacuum pump housing according to any one of claims 1 to 9, characterized in that, The number of blanks is two, namely the upper stator housing blank and the lower stator housing blank of the vacuum pump; The processing method for the vacuum pump housing includes: Provide upper stator housing blank and lower stator housing blank; The upper stator housing blank and the lower stator housing blank are assembled together to form a pre-assembled housing assembly; One end face of the pre-assembled shell is machined into a reference surface; Using the reference plane as the positioning reference, a mating surface, a pump cavity, a bearing hole, a flange hole, and a sealing surface are machined on the housing pre-assembly; wherein, the same machining parameters are used for machining the bearing hole, the flange hole, and the sealing surface; The pre-assembled housing is disassembled and reassembled, and then the upper stator housing blank and the lower stator housing blank are respectively finely finished to obtain the upper stator housing and the lower stator housing; The upper stator housing and the lower stator housing are assembled together to obtain the vacuum pump housing.

11. A vacuum pump, characterized in that, The vacuum pump housing is manufactured by the method described in any one of claims 1 to 10.

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