Screw rotor and vacuum pump

Abstract

The utility model provides a screw rotor and a vacuum pump. The screw rotor comprises a rotating shaft and a plurality of rotor blades, the plurality of rotor blades are sleeved on the rotating shaft; each rotor blade comprises a tooth top part, a tooth root part, a chamfer surface and an end surface; the end face is configured to be penetrated by a rotating shaft. The tooth top is provided with a tooth top surface, and the tooth root is provided with a tooth root surface; one side of the chamfered surface is connected with the edge of the tooth top surface, and the other side of the chamfered surface is connected with the edge of the end surface; the tooth root face is provided with a concave part, and the side wall of the concave part is matched with the chamfer face. According to the screw rotor, the chamfered surfaces are arranged at the tooth tops of the rotor blades, and the concave part side walls matched with the chamfered surfaces at the tooth tops are correspondingly arranged at the tooth root parts, so that the machining error caused by secondary positioning of a rotating procedure is avoided on the basis of reducing a gap in the meshing process of the screw rotor; therefore, the sealing precision of the vacuum pump is improved, and finally the working efficiency of the vacuum pump comprising the screw rotor provided by the utility model is improved.

Description

Technical Field

[0001] This application relates to the field of vacuum technology, and more specifically, to a screw rotor and a vacuum pump. Background Technology

[0002] Taking a common positive displacement vacuum pump as an example, it mainly uses the reciprocating motion of a pair of meshing rotors to cause the volume of the working chamber between the rotors and the pump body to change periodically, thereby realizing the intake, transport, compression, and discharge of process gases and creating a vacuum at the pump inlet. Small gaps between the rotors and the pump body, and between the rotors themselves, achieve the sealing of the working chamber. As a form of approximate sealing, these small gaps have a dominant influence on the vacuum pump's backflow, efficiency, and process adaptability.

[0003] To achieve a tight seal, most current vacuum pumps typically employ a clean-cut design for the curved surfaces of the pump body's cavities. During machining, the mating surfaces of the upper and lower cavities are usually machined on a vertical milling machine, then transferred to a horizontal machining center to machine multiple curved surfaces. However, the machining errors caused by the secondary positioning during this transfer process lead to a loss of precision in the machining of the vacuum pump.

[0004] In other words, most vacuum pumps currently available suffer from insufficient sealing precision due to limitations in their manufacturing processes, which in turn results in low operating efficiency. Utility Model Content

[0005] The purpose of this application is to provide a screw rotor and a vacuum pump, which, through the chamfering design between the tooth tip and end face of the screw rotor and the adaptive structural design at the tooth root that can mesh with the tooth tip, can avoid the machining error caused by the secondary positioning of the rotating process, thereby improving the sealing accuracy of the vacuum pump and ultimately improving the working efficiency of the vacuum pump.

[0006] In a first aspect, this application provides a screw rotor, including a rotating shaft and a plurality of rotor blades; the plurality of rotor blades are sleeved on the rotating shaft; the rotor blades include a tooth tip, a tooth root, a chamfered surface, and an end face; the end face is configured to be penetrated by the rotating shaft; the tooth tip has a tooth top surface, and the tooth root has a tooth root surface; one side of the chamfered surface is connected to the edge of the tooth top surface, and the other side of the chamfered surface is connected to the edge of the end face; the tooth root surface has a recessed portion, and the sidewall of the recessed portion is adapted to the chamfered surface.

[0007] The aforementioned screw rotor, by providing a chamfered surface at the tip of the rotor blade teeth and a recessed sidewall at the root of the teeth that matches the chamfered surface, reduces the clearance during the meshing process of the screw rotor. Furthermore, since the screw rotor operates within the vacuum pump body, the inner wall of the pump body typically needs to match the tip of the teeth to minimize the clearance between the screw rotor and the pump body and ensure a tight seal between them, the inner wall of the pump body's cavity can also be designed with a structure similar to the tooth root. This avoids machining errors caused by secondary positioning during the rotation process, thereby improving the sealing accuracy of the vacuum pump and ultimately increasing the working efficiency of the vacuum pump containing the screw rotor provided in this application.

[0008] In conjunction with the first aspect, optionally, the chamfered surface includes an outer rounded corner surface; the sidewall of the recess includes an inner rounded corner surface; the opening of the outer rounded corner surface faces the inner rounded corner of the rotor blade; and the opening of the end face profile of the outer rounded corner surface faces the rotating shaft.

[0009] The aforementioned screw rotor, by further refining the chamfered surface into a rounded corner surface and adapting the tooth root and pump body, further eliminates the sharp edges on the tooth tips, thereby alleviating the stress concentration problem caused by the sharp edges and ultimately improving the service life and operational stability of the screw rotor. Furthermore, it further improves the fit between screw rotors and between the screw rotor and the pump body, thereby further improving the sealing accuracy of the vacuum pump and ultimately further improving the working efficiency of the vacuum pump.

[0010] In conjunction with the first aspect, optionally, the tangent of the end face profile of the outer rounded corner surface is coplanar with the straight line containing the axis of rotation.

[0011] The aforementioned screw rotor, through the design that the tangent of the end face profile of the outer rounded corner surface is coplanar with the straight line where the shaft is located, makes the end face profile of the outer rounded corner surface coplanar with one of the planes passing through the straight line where the shaft is located. This simplifies the modeling and calculation process in the chamfering process at the connection between the end face and the tooth tip surface, and ultimately simplifies the manufacturing process of the screw rotor.

[0012] In conjunction with the first aspect, optionally, the end face profile of the outer rounded corner surface is an arc.

[0013] The aforementioned screw rotor, due to the arc-shaped end face profile of its outer rounded corners, exhibits a more uniform curvature distribution. This results in a more even distribution of contact forces between screw rotors and between the screw rotor and the pump body, ultimately reducing gas backflow during vacuum pump operation and further improving the working efficiency of the high vacuum pump. Furthermore, because the curvature is equal at all points on the arc, the chamfered surface can be machined in a single pass using a vertical milling machine or CNC machine tool, thereby reducing errors introduced by subsequent steps.

[0014] In conjunction with the first aspect, optionally, the radius of the outer rounded corner surface is R1, and the radius of the inner rounded corner surface is R2; wherein the ratio of R1 to R2 is in the range of [1.2, 1.5].

[0015] The aforementioned screw rotor, by limiting the ratio of R1 to R2 to the range of [1.2, 1.5], further optimizes the clearances between screw rotors and between the screw rotor and the body, ensuring that no machining process is required. This further reduces gas backflow during the operation of the vacuum pump containing the screw rotor provided in this application, thereby improving the working efficiency of the vacuum pump.

[0016] In conjunction with the first aspect, optionally, the rotor blade further includes a tooth profile portion; the tooth profile portion is located between the tooth tip and the tooth root portion; the tooth profile portion has a tooth profile surface; the tooth profile surface is connected to the end face edge.

[0017] In the aforementioned screw rotor, in a vacuum pump comprising two meshing screw rotors as provided in this application, the tooth profile of one screw rotor typically meshes with the tooth profile of the other screw rotor. Therefore, by retaining the original sharp edges at the connection between the tooth profile surface and the end face, the meshing degree between the tooth profiles is improved, thereby correspondingly reducing the gap between the tooth profiles during meshing, and further improving the sealing accuracy of the high vacuum pump.

[0018] In conjunction with the first aspect, optionally, the tooth profile surface is connected to the recessed portion via a first transition surface; the tooth profile surface is connected to the tooth tip surface via a second transition surface; the first transition surface is an arc surface with a radius of R1' for the end face profile, and at least one tangent of the end face profile of the first transition surface is parallel to the length direction of the rotation axis; the second transition surface is an arc surface with a radius of R2', and at least one tangent of the end face profile of the second transition surface is parallel to the length direction of the rotation axis; wherein, the value range of R1' includes the interval [1.05R2, 1.2R2], the value range of R2' includes the interval [0.8R1, R1], R1 is the radius of the outer rounded corner surface, and R2 is the radius of the inner rounded corner surface.

[0019] The aforementioned screw rotor, by defining the value range of R1' as [1.05R2, 1.2R2], achieves flexible selection between processing efficiency and sealing performance, and can adapt to different working conditions. By defining the value range of R2' as [0.8R1, R1], it avoids processing errors caused by secondary positioning in the rotation process, balances the structural strength of the tooth tip with processing costs, reduces backflow during vacuum pump operation, and thus further improves the working efficiency of the vacuum pump.

[0020] In a second aspect, this application provides a vacuum pump, including a housing and a screw rotor as described in the first aspect; the housing surrounds and forms a cavity; the shaft of the screw rotor passes through the housing, and the rotor blades of the screw rotor are located within the cavity.

[0021] The vacuum pump described above has the same beneficial effects as the first aspect or any alternative embodiment of the first aspect, and will not be repeated here.

[0022] In conjunction with the second aspect, optionally, the housing is formed by surrounding the cavity with an inner wall; the inner wall of the cavity includes a vertical surface and a bottom surface; the plane containing the vertical surface is parallel to the plane containing the end face of the rotor blade; at least one tangent of the end face profile of the bottom surface is parallel to the end face and perpendicular to the length direction of the rotating shaft; the bottom surface is connected to the vertical surface through a third transition surface; the third transition surface is adapted to the chamfered surface of the rotor blade.

[0023] The aforementioned vacuum pump improves its sealing accuracy and ultimately its working efficiency by setting a third transition surface on the inner wall of the cavity that matches the chamfered surface on the rotor blades, thus mitigating the machining errors caused by the secondary positioning during the rotation process.

[0024] In conjunction with the second aspect, optionally, the housing includes a first housing and a second housing; the first housing has a first opening facing the second housing; the second housing has a second opening facing the first housing; the first opening has a first opening edge and a first hole edge for the rotating shaft to pass through, and the second opening has a second opening edge and a second hole edge for the rotating shaft to pass through; wherein, when the first housing and the second housing are combined, the first hole edge and the second hole edge form a through hole for the rotating shaft to pass through; a sealing groove is provided on the first opening edge and / or the second opening edge, and a sealing ring is provided in the sealing groove; the first opening edge and the second opening edge are sealed together by the sealing ring.

[0025] The aforementioned vacuum pump further improves the sealing performance when the first and second housings are joined by setting a sealing ring between them, which in turn further improves the sealing performance of the vacuum pump and thus further improves its working efficiency.

[0026] In summary, the screw rotor and vacuum pump provided in this application, by providing a chamfered surface at the tip of the rotor blade teeth and a corresponding recessed sidewall at the root of the teeth that matches the chamfered surface, reduce the clearance during the meshing process of the screw rotor and avoid machining errors caused by secondary positioning in the rotation process, thereby improving the sealing accuracy of the vacuum pump and ultimately increasing the working efficiency of the vacuum pump containing the screw rotor provided in this application. By further defining the chamfered surface as a rounded corner surface and performing adaptation treatment on the tooth root and pump body, the service life and operational stability of the screw rotor are improved, and the fit between screw rotors and between the screw rotor and the pump body is further improved, thereby further improving the sealing accuracy of the vacuum pump. The design that the tangent of the end face profile of the outer rounded corner surface is coplanar with the straight line where the shaft is located simplifies the manufacturing process of the screw rotor. By defining the end face profile of the outer rounded corner as an arc, the contact force distribution between screw rotors and between the screw rotor and the pump body becomes more uniform, ultimately reducing gas backflow during vacuum pump operation, further improving the working efficiency of the high vacuum pump, and also reducing errors caused by the rotation sequence. Attached Figure Description

[0027] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 A perspective view of the screw rotor provided in an embodiment of this application;

[0029] Figure 2 This is a first perspective view of the rotor blades in the screw rotor provided in an embodiment of this application;

[0030] Figure 3 A perspective view of a screw rotor provided in an embodiment of this application, showing two screw rotors meshing with each other;

[0031] Figure 4 A front view of the rotor blades in a screw rotor provided in an embodiment of this application;

[0032] Figure 5 This is a cross-sectional view of the root of the rotor blades in a screw rotor provided in an embodiment of this application;

[0033] Figure 6 This is a second perspective view of the rotor blades in the screw rotor provided in an embodiment of this application;

[0034] Figure 7A perspective view of the vacuum pump provided in the embodiments of this application;

[0035] Figure 8 A cross-sectional view and a partial enlarged view of the vacuum pump provided in the embodiments of this application;

[0036] Figure 9 A perspective view of the first housing in the vacuum pump provided in the embodiments of this application;

[0037] Figure 10 A perspective view of the second housing in a vacuum pump provided in an embodiment of this application.

[0038] Icons: 100, Screw rotor; 110, Shaft; 120, Rotor blade; 121, Tooth tip; 1211, Tooth tip surface; 122, Tooth root; 1221, Recess; 1222, Side wall; 123, Chamfered surface; 124, End face; 125, Tooth profile; 1251, Tooth profile surface; 126, First transition surface; 127, Second transition surface; 10, Vacuum pump; 200, Housing; 210, First housing; 211, First opening edge; 220, Second housing; 221, Second opening edge; 231, Vertical surface; 232, Bottom surface; 233, Third transition surface; 240, Sealing ring. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, 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. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0040] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0041] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0042] In the description of this application, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the utility model product is in use. They are 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. Therefore, they should not be construed as limitations on this application. In addition, the terms "first," "second," and "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0043] Furthermore, terms such as "horizontal" and "vertical" do not imply that components must be absolutely horizontal or suspended, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0044] In the description of this application, it should also be noted that, unless otherwise expressly specified and limited, the terms "set up," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0045] Please refer to Figure 1 and Figure 2 , Figure 1 This is a perspective view of the screw rotor 100 provided in an embodiment of this application; Figure 2 This is a first perspective view of the rotor blades 120 in the screw rotor 100 provided in this application embodiment. The screw rotor 100 provided in this application embodiment may include a rotating shaft 110 and a plurality of rotor blades 120; the plurality of rotor blades 120 may be sleeved on the rotating shaft 110; the rotor blades 120 may include a tooth tip 121, a tooth root 122, a chamfered surface 123, and an end face 124; the end face 124 may be configured to be penetrated by the rotating shaft 110; the tooth tip 121 may have a tooth tip surface 1211, and the tooth root 122 may have a tooth root surface; one side of the chamfered surface 123 may be connected to the edge of the tooth tip surface 1211, and the other side of the chamfered surface 123 may be connected to the edge of the end face 124; the tooth root surface may have a recessed portion 1221, and the sidewall 1222 of the recessed portion 1221 may be adapted to the chamfered surface 123.

[0046] The rotor blades 120 can be figure-eight shaped blades, cloverleaf blades, etc., as known to those skilled in the art. In a vacuum pump 10, two identical, meshing screw rotors 100 are typically included. In this case, the figure-eight shaped rotor blades 120 and cloverleaf rotor blades 120 usually need to have tooth roots 122 and tooth tips 121, similar to gears. In the vacuum pump 10, the tooth root 122 of one screw rotor 100 meshes with the tooth tip 121 of the other screw rotor 100. Correspondingly, the tooth tip surface 1211 can be the arc-shaped surface on the tooth tip 121 of one screw rotor 100 that contacts the tooth root 122 of the other screw rotor 100 during meshing. Conversely, the tooth root surface is the arc-shaped surface that contacts the tooth tip 121 of the other screw rotor 100 during meshing.

[0047] The end face profile of the tooth tip 1211 can be a circular arc, an elliptical arc, an involute, etc., and the end face profile of the tooth root can also be a circular arc, an elliptical arc, an involute, etc.

[0048] The end face 124 of the rotor blade 120 can be located on the surfaces at both ends along the length of the shaft 110. Taking a cylinder as an example, there are usually sharp edges at the connection between the end face 124 and the side surface of the cylinder. If the end face 124 of the rotor blade 120 is directly connected to the tooth tip surface 1211, or to the tooth root surface, sharp edges will also exist. However, in this embodiment, the end face 124 of the rotor blade 120 and the tooth tip surface 1211 are connected by a chamfered surface 123, which can eliminate the sharp edges to a certain extent. On the basis of the two surfaces being connected by the chamfered surface 123, similar to the two surfaces being directly connected, the sharp edges are "removed". Accordingly, please refer to Figure 3 , Figure 3 This is a perspective view of two screw rotors 100 provided in this embodiment of the application, in a meshing state. In order to better adapt the tooth root portion 122 to the tooth tip 121 and reduce the gap when the screw rotors 100 mesh, the tooth root portion 122 can be provided with a recessed portion 1221. This design is similar to appropriately providing a portion of the tooth tip 121 that is "eliminated" at both ends of the tooth root portion 122 in the length direction of the shaft 110, and thus the two ends of the tooth root portion 122 form protrusions.

[0049] Among them, the chamfered surface 123 can be a plane or a rounded surface. It is worth mentioning that the end face profile of the rounded surface is not necessarily a circular arc, but can also include other arcs, such as elliptical arcs, parabolas, hyperbolas, etc.

[0050] In the above implementation process, by providing a chamfered surface 123 on the tooth tip 121 of the rotor blade 120 and providing a recessed portion 1221 sidewall 1222 corresponding to the chamfered surface 123 on the tooth root 122, the gap during the meshing process of the screw rotor 100 is reduced. Since the screw rotor 100 operates in the pump body of the vacuum pump 10, in order to reduce the gap between the screw rotor 100 and the body and ensure the sealing between the screw rotor 100 and the pump body, the inner wall of the pump body cavity usually also needs to be adapted to the tooth tip 121. Therefore, the inner wall of the body cavity cavity can also be designed with a structure similar to the tooth root 122, thereby avoiding the processing error caused by the secondary positioning of the rotating process, thereby improving the sealing accuracy of the vacuum pump 10, and ultimately improving the working efficiency of the vacuum pump 10 including the screw rotor 100 provided in the embodiments of this application.

[0051] Please combine Figure 2 Reference Figure 4 and Figure 5 , Figure 4 This is a front view of the rotor blades 120 in the screw rotor 100 provided in the embodiments of this application; Figure 5 This is a cross-sectional view of the root 122 of the rotor blade 120 in the screw rotor 100 provided in this application embodiment. In some optional embodiments, the chamfered surface 123 may include an outer rounded corner surface; the sidewall 1222 of the recess 1221 may include an inner rounded corner surface; the opening of the outer rounded corner surface may face the inner rounded corner of the rotor blade 120; the opening of the end face profile of the outer rounded corner surface may face the rotating shaft 110.

[0052] As mentioned earlier, the end face profile of an outer rounded corner can be a circular arc, an elliptical arc, a parabola, or a hyperbola, etc. Similarly, the end face profile of an inner rounded corner can also be a circular arc, an elliptical arc, a parabola, or a hyperbola, etc.

[0053] In the above implementation process, by further defining the chamfered surface 123 as a rounded surface and performing adaptation treatment on the tooth root 122 and the pump body, the sharp edges on the tooth tip 121 are further eliminated, thereby further alleviating the problem of stress concentration at the sharp edges, ultimately improving the service life and operational stability of the screw rotor 100. Furthermore, the fit between screw rotors 100 and between the screw rotor 100 and the pump body is further improved, thereby further improving the sealing accuracy of the vacuum pump 10, and ultimately further improving the working efficiency of the vacuum pump 10.

[0054] Please refer to the reference image. Figure 2 , Figure 4 and Figure 5 In some alternative implementations, the tangent of the end face profile of the outer rounded corner can be coplanar with the straight line where the pivot 110 is located.

[0055] For example, if the end face profile of the outer rounded corner is an arc, then the outer rounded corner can be a partial side surface of a cylinder. The axis around which this side surface of the cylinder is surrounded can be parallel to the line containing the rotation axis 110. Alternatively, if the end face profile of the outer rounded corner is an elliptical arc, then the outer rounded corner can be a partial side surface of an elliptical cylinder. The foci of all sections perpendicular to the length direction of the elliptical cylinder can form an axis of the elliptical cylinder, which can also be parallel to the line containing the rotation axis 110.

[0056] In the above implementation process, by designing the tangent of the end face profile of the outer rounded corner surface to be coplanar with the straight line of the rotating shaft 110, the end face profile of the outer rounded corner surface is made coplanar with one of the planes passing through the straight line of the rotating shaft 110. This simplifies the modeling and calculation process in the chamfering process at the connection between the end face 124 and the tooth tip surface 1211, and ultimately simplifies the manufacturing process of the screw rotor 100.

[0057] Please refer to the reference image. Figure 2 , Figure 4 and Figure 5 In some optional implementations, the end face profile of the outer rounded corner can be an arc.

[0058] In other words, the outer rounded corner can be part of the side surface of a cylinder.

[0059] In the above implementation process, since the end face profile of the outer rounded corner surface is an arc, the curvature distribution of the end face profile of the outer rounded corner surface is more uniform. This results in a more uniform distribution of contact force between screw rotors 100 and between screw rotors 100 and the pump body, ultimately reducing gas backflow during the operation of the vacuum pump 10 and further improving the working efficiency of the vacuum pump 10. Furthermore, since the curvature is equal at all points on the arc, the chamfered surface 123 can be machined in one step using a vertical milling machine or a CNC machine tool, thereby reducing errors caused by sequential processing.

[0060] Please refer to the reference image. Figure 2 , Figure 4 and Figure 5 In some optional embodiments, the radius of the outer rounded corner is R1, and the radius of the inner rounded corner is R2; wherein the ratio of R1 to R2 may include the range of [1.2, 1.5].

[0061] Although the inner and outer rounded corners are compatible, their radii are not strictly equal. Therefore, the range of the ratio of R1 to R2 can be defined.

[0062] For example, when the ratio of R1 to R2 is 1.2, R2 = 10mm, R1 = 1.2 × R1 = 1.2 × 10 = 12mm. In this case, the smaller ratio of R1 to R2 is more suitable for the tool size of the vertical milling machine (such as a Φ12mm disc milling cutter), which can reduce the tool change frequency and thus improve machining efficiency. When the ratio of R1 to R2 is 1.3, R2 = 10mm, R1 = 1.3 × R1 = 1.3 × 10 = 13mm. In this case, the tooth tip radius is increased (13mm), which can further reduce the local friction between the screw rotor 100 and the stator cavity (pump body), thereby further reducing backflow. Furthermore, when the ratio of R1 to R2 is 1.3, the curvature difference between the tooth tip and tooth root radius is more suitable for the centrifugal force distribution during high-speed rotation, reducing vibration and noise. It can also be adapted to medium-sized tools (such as a Φ13mm disc milling cutter) and can still complete the machining in one sequence without changing the process. When the ratio of R1 to R2 is 1.5, R2 = 10mm, R1 = 1.5 × R1 = 1.5 × 10 = 15mm. Under these conditions, the maximum tooth tip radius (15mm) significantly increases the sealing contact area with the stator cavity (pump body), thereby further reducing backflow.

[0063] In the above implementation process, by limiting the ratio of R1 to R2 to [1.2, 1.5], the gaps between screw rotors 100 and between screw rotors 100 and the body are further optimized while ensuring that no additional processing steps are required. This further reduces gas backflow during the operation of the vacuum pump 10, which includes the screw rotor 100 provided in this embodiment, thereby improving the working efficiency of the vacuum pump 10.

[0064] Please combine Figure 2 Reference Figure 6 , Figure 6 This is a second perspective view of the rotor blade 120 in the screw rotor 100 provided in this application embodiment. In some optional embodiments, the rotor blade 120 may further include a tooth profile portion 125; the tooth profile portion 125 may be located between the tooth tip 121 and the tooth root portion 122; the tooth profile portion 125 may have a tooth profile surface 1251; the tooth profile surface 1251 is corner-connected to the end face 124.

[0065] In other words, the connection between the tooth profile surface 1251 and the end face 124 is neither chamfered like the tooth tip 121 nor recessed like the tooth root 122; instead, the two are directly connected. With the tooth profile surface 1251 and the end face 124 directly connected, there will be sharp edges at the connection point.

[0066] In the above implementation process, since the tooth profile 125 of one screw rotor 100 typically meshes with the tooth profile 125 of the other screw rotor 100 in the vacuum pump 10 which includes two meshing screw rotors 100 provided in this application, by retaining the original sharp edges at the connection between the tooth profile surface 1251 and the end face 124, the meshing degree between the tooth profiles 125 and 125 is better, and the gap between the tooth profiles 125 and 125 in the meshing condition is correspondingly reduced, thereby further improving the sealing accuracy of the vacuum pump 10.

[0067] Please continue to refer to Figure 2 and Figure 6 In some optional embodiments, the tooth profile surface 1251 can be connected to the recess 1221 via the first transition surface 126; the tooth profile surface 1251 can be connected to the tooth tip surface 1211 via the second transition surface 127; the first transition surface 126 can be an arc surface with a radius of R1' of the end face profile, and at least one tangent of the end face profile of the first transition surface 126 can be parallel to the length direction of the rotating shaft 110; the second transition surface 127 can be an arc surface with a radius of R2', and at least one tangent of the end face profile of the second transition surface 127 can be parallel to the length direction of the rotating shaft 110; wherein, the value range of R1' can include the interval [1.05R2, 1.2R2], the value range of R2' can include the interval [0.8R1, R1], R1 is the radius of the outer rounded corner surface, and R2 is the radius of the inner rounded corner surface.

[0068] Taking R2 = 10mm and R1 = 1.2 × R2 = 12mm as an example, when R1 = 1.05R2 = 10.5mm, the curvature of the first transition surface 126 is close to that of the inner fillet surface. Therefore, it is possible to directly use tools of the same diameter for continuous machining, thereby reducing the number of tool changes. When R1' = 1.1R2 = 11mm, the curvature of the first transition surface 126 is increased by about 10% on the basis of R1' = 10.5mm. This allows it to be adapted to tools such as Φ11mm disc milling cutters, and the smooth connection between the first transition surface 126 and the tooth profile surface 1251 can reduce backflow. When R1' = 1.2R2 = 12mm, although it is necessary to switch to a larger tool (Φ12mm), it is still within the working range of the vertical milling machine. Furthermore, the increased curvature of the first transition surface 126 can create a more uniform meshing gap between the screw rotor 100 and the stator cavity, thereby further reducing backflow.

[0069] Taking R1 = 12mm as an example, when R2' = 0.8R1 = 9.6mm, the curvature of the second transition surface 127 is relatively small, which can improve the deformation resistance of the tooth tip surface 1211 connected to it, thus making it more suitable for high-speed rotation. When R2' = 0.9R1 = 10.8mm, the curvature of the second transition surface 127 is slightly smaller than the curvature of the outer fillet surface (R1 = 12mm), which can ensure machining efficiency (compatible with Φ10.8mm tools), avoid stress concentration, and reduce backflow. When R2' = 1.0R1 = 12mm, the curvature of the second transition surface 127 is consistent with the curvature of the outer fillet surface, so no additional tool adjustment is required, which can improve machining efficiency and reduce backflow.

[0070] In the above implementation process, by determining the value range of R1' to be [1.05R2, 1.2R2], a flexible choice between processing efficiency and sealing performance can be achieved, and it can also adapt to different working conditions. By determining the value range of R2' to be [0.8R1, R1], while avoiding the processing errors caused by secondary positioning during the transition process, the structural strength and processing cost of the tooth tip 121 are balanced, and the backflow during the operation of the vacuum pump 10 is reduced, thereby further improving the working efficiency of the vacuum pump 10.

[0071] Please refer to Figure 7 , Figure 7 This is a perspective view of the vacuum pump 10 provided in the embodiments of this application. Based on the same concept, the embodiments of this application provide a vacuum pump 10, which may include a housing 200 and the screw rotor 100 described above; the housing 200 may form a cavity; the shaft 110 of the screw rotor 100 may pass through the housing 200, and the rotor blades 120 of the screw rotor 100 may be located in the cavity.

[0072] Taking a Roots vacuum pump as an example, it may include two screw rotors 100.

[0073] The above implementation process is the same as that of the screw rotor 100 described above, and will not be repeated here.

[0074] Please refer to Figures 8 to 10 , Figure 8 Cross-sectional view and partial enlarged view of the vacuum pump 10 provided in the embodiments of this application; Figure 9 This is a perspective view of the first housing 210 in the vacuum pump 10 provided in the embodiments of this application; Figure 10This is a perspective view of the second housing 220 in the vacuum pump 10 provided in this application embodiment. In some optional embodiments, the housing 200 can form a cavity by surrounding the inner wall of the cavity; the inner wall of the cavity can include a vertical surface 231 and a bottom surface 232; the plane where the vertical surface 231 is located can be parallel to the plane where the end face 124 of the rotor blade 120 is located; at least one tangent of the end face profile of the bottom surface 232 can be parallel to the end face 124 and can be perpendicular to the length direction of the rotating shaft 110; the bottom surface 232 can be connected to the vertical surface 231 by a third transition surface 233; the third transition surface 233 can be adapted to the chamfered surface 123 of the rotor blade 120.

[0075] The end face profile of the bottom surface 232 can be an arc, and the radius of the arc can be slightly larger than the maximum radius of the rotor blade 120. The end face profile of the third transition surface 233 can be the same as the end face profile of the side wall 1222 of the recess 1221.

[0076] In the above implementation process, by setting a third transition surface 233 on the inner wall of the cavity that matches the chamfered surface 123 on the rotor blade 120, the sealing accuracy of the vacuum pump 10 is improved due to the machining error caused by the secondary positioning of the rotating process, and the working efficiency of the vacuum pump 10 is ultimately improved.

[0077] Please continue to refer to Figure 9 and Figure 10 In some optional embodiments, the housing 200 may include a first housing 210 and a second housing 220; the first housing 210 may have a first opening facing the second housing 220; the second housing 220 may have a second opening facing the first housing 210; the first opening may have a first opening edge 211 and a first hole edge through which the rotating shaft 110 passes, and the second opening may have a second opening edge 221 and a second hole edge through which the rotating shaft 110 passes; wherein, when the first housing 210 and the second housing 220 are combined, the first hole edge and the second hole edge may form a through hole through which the rotating shaft 110 passes; a sealing groove may be provided on the first opening edge 211 and / or the second opening edge 221, and a sealing ring 240 may be provided in the sealing groove; the first opening edge 211 and the second opening edge 221 may be sealed together by the sealing ring 240.

[0078] The sealing groove can be provided only on the first opening edge 211 of the first housing 210, or only on the second opening edge 221 of the second housing 220, or it can be provided on both the first opening edge 211 and the second opening edge 221. Preferably, the position of the sealing groove on the first opening edge 211 does not correspond to the position of the sealing groove on the second opening edge 221. The sealing ring 240 can be made of nitrile rubber, fluororubber, silicone rubber, etc.

[0079] In the above implementation process, by setting a sealing ring 240 between the first housing 210 and the second housing 220, the sealing performance when the first housing 210 and the second housing 220 are combined is further improved, that is, the sealing performance of the vacuum pump 10 is further improved, thereby further improving the working efficiency of the vacuum pump 10.

[0080] In summary, the screw rotor 100 and vacuum pump 10 provided in the various embodiments of this application, by providing a chamfered surface 123 on the tooth tip 121 of the rotor blade 120 and a sidewall 1222 corresponding to the chamfered surface 123 on the tooth root 122, reduce the gap during the meshing process of the screw rotor 100 and avoid the machining error caused by the secondary positioning of the rotating process, thereby improving the sealing accuracy of the vacuum pump 10 and ultimately improving the working efficiency of the vacuum pump 10 including the screw rotor 100 provided in the embodiments of this application. By further defining the chamfered surface 123 as a rounded surface and performing adaptation treatment on the tooth root 122 and the pump body, the service life and operational stability of the screw rotor 100 are improved, and the fit between screw rotors 100 and between the screw rotor 100 and the body is further improved, thereby further improving the sealing accuracy of the vacuum pump 10. By designing the tangent of the end face profile of the outer rounded corner surface to be coplanar with the straight line containing the rotating shaft 110, the manufacturing process of the screw rotor 100 is simplified. By defining the end face profile of the outer rounded corner surface as an arc, the contact force distribution between screw rotors 100 and between the screw rotor 100 and the pump body is made more uniform, ultimately reducing gas backflow during the operation of the vacuum pump 10, further improving the working efficiency of the vacuum pump 10, and also reducing errors caused by the rotation sequence.

[0081] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A screw rotor, characterized in that, It includes a rotating shaft and several rotor blades; the several rotor blades are sleeved on the rotating shaft; The rotor blade includes a tooth tip, a tooth root, a chamfered surface, and an end face; the end face is configured to be penetrated by the rotating shaft. The tooth tip has a tooth tip surface, and the tooth root has a tooth root surface; One side of the chamfered surface is connected to the edge of the tooth tip surface, and the other side of the chamfered surface is connected to the edge of the end face; The tooth root surface has a recessed portion, and the sidewall of the recessed portion is adapted to the chamfered surface.

2. The screw rotor according to claim 1, characterized in that, The chamfered surface includes an outer rounded corner surface; the sidewall of the recessed portion includes an inner rounded corner surface; The opening of the outer rounded corner surface faces the inner rounded corner of the rotor blade; The opening of the end face profile of the outer rounded corner face faces the rotating shaft.

3. The screw rotor according to claim 2, characterized in that, The tangent of the end face profile of the outer rounded corner is coplanar with the straight line containing the pivot.

4. The screw rotor according to claim 3, characterized in that, in, The end face profile of the outer rounded corner surface is an arc.

5. The screw rotor according to claim 4, characterized in that, The radius of the outer rounded corner is R1, and the radius of the inner rounded corner is R2; wherein the ratio of R1 to R2 is in the range of [1.2, 1.5].

6. The screw rotor according to any one of claims 2 to 5, characterized in that, The rotor blades also include tooth profiles; The tooth profile portion is located between the tooth tip and the tooth root portion; the tooth profile portion has a tooth profile surface; The tooth profile surface is connected to the end face corner.

7. The screw rotor according to claim 6, characterized in that, The tooth profile surface is connected to the recessed portion through a first transition surface; the tooth profile surface is connected to the tooth tip surface through a second transition surface; The first transition surface is an arc surface with a radius of R1' of the end face profile, and at least one tangent of the end face profile of the first transition surface is parallel to the length direction of the rotating shaft; The second transition surface is an arc surface with a radius of R2', and at least one tangent of the end face profile of the second transition surface is parallel to the length direction of the rotating shaft; Wherein, the value range of R1' includes the interval [1.05R2, 1.2R2], the value range of R2' includes the interval [0.8R1, R1], R1 is the radius of the outer rounded corner surface, and R2 is the radius of the inner rounded corner surface.

8. A vacuum pump, characterized in that, Includes a housing and a screw rotor according to any one of claims 1 to 7; The shell surrounds and forms a cavity; The shaft of the screw rotor passes through the housing, and the rotor blades of the screw rotor are located inside the cavity.

9. The vacuum pump according to claim 8, characterized in that, The housing is formed by surrounding the inner wall of the cavity; The inner wall of the cavity includes a vertical surface and a bottom surface; The plane containing the elevation is parallel to the plane containing the end face of the rotor blade; At least one tangent of the end face profile of the bottom surface is parallel to the end face and perpendicular to the length direction of the pivot. The bottom surface is connected to the elevation surface via a third transition surface; The third transition surface is adapted to the chamfered surface of the rotor blade.

10. The vacuum pump according to claim 8, characterized in that, The housing includes a first housing and a second housing; The first housing has a first opening facing the second housing; The second housing has a second opening facing the first housing; The first opening has a first opening edge and a first hole edge through which the rotating shaft passes; the second opening has a second opening edge and a second hole edge through which the rotating shaft passes; wherein, when the first housing and the second housing are combined, the first hole edge and the second hole edge form a through hole through which the rotating shaft passes. A sealing groove is provided on the edge of the first opening and / or the edge of the second opening, and a sealing ring is provided in the sealing groove; The first opening edge and the second opening edge are sealed together by the sealing ring.

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