Design method and device for long-pendulum-lobe type roots pump rotor profile with sealing arc

Abstract

This application relates to a method and apparatus for designing the rotor profile of a long cycloidal Roots pump with a sealing arc. It includes: acquiring the profile design curve; determining the outer large cycloidal curve, outer small cycloidal curve, and sealing arc of the profile design based on the curve; determining the conjugate curves of the inner large cycloidal curve, inner small cycloidal curve, and sealing arc of the profile design based on the outer large cycloidal curve, outer small cycloidal curve, and sealing arc; and obtaining the rotor profile of the profile design based on the symmetry of the outer large cycloidal curve, outer small cycloidal curve, sealing arc, inner large cycloidal curve, inner small cycloidal curve, sealing arc, and the rotor profile. The rotor profile of this application has a high volumetric efficiency, significantly improving the effective pumping speed, compression ratio, and ultimate vacuum of the rotor.

Description

Technical Field

[0001] This invention relates to the field of rotor profile design technology, and more specifically, to a method and apparatus for designing the rotor profile of a long cycloidal Roots pump with a sealing arc. Background Technology

[0002] Roots pumps are mainly used in semiconductor, vacuum coating, metallurgy, chemical, papermaking, food and electronics industries.

[0003] Currently, the main rotor profiles for Roots pumps on the market are involute, cycloid, and circular arc, collectively referred to as standard profiles. Standard profile rotors are easier to design and manufacture, but they tend to have lower effective pumping speed, compression ratio, and ultimate vacuum, and generate more noise. Summary of the Invention

[0004] This application provides a method and apparatus for designing the rotor profile of a long cycloidal Roots pump with a sealing arc. To provide a basic understanding of some aspects of the disclosed embodiments, a brief summary is given below. This summary is not intended as a general commentary, nor is it intended to identify key / important components or describe the scope of protection of these embodiments. Its sole purpose is to present some concepts in a simple form as a prelude to the detailed description that follows.

[0005] In a first aspect, embodiments of this application provide a method for designing the rotor profile of a long cycloidal Roots pump with a sealing arc, the method comprising:

[0006] The curves in the profile design are collected;

[0007] Based on the curve, determine the outer large rounded cycloid of the pitch circle, the outer small rounded cycloid of the pitch circle, and the sealing arc of the profile design;

[0008] Based on the outer large cycloid of the pitch circle, the outer small cycloid of the pitch circle, and the sealing arc, determine the conjugate curves of the inner large cycloid of the pitch circle, the inner small cycloid of the pitch circle, and the sealing arc of the profile design.

[0009] Based on the symmetry of the outer large cycloid of the pitch circle, the outer small cycloid of the pitch circle, the sealing arc, the conjugate curve of the inner large cycloid of the pitch circle, the conjugate curve of the inner small cycloid of the pitch circle, the conjugate curve of the sealing arc, and the rotor profile, the entire rotor profile of the profile design is obtained.

[0010] Optionally, the curve of the acquisition profile design includes:

[0011] Acquire the pitch circle outer curve of the profile design;

[0012] The outer curve of the pitch circle is used as the curve for the profile design.

[0013] Optionally, determining the conjugate curves of the large outer cycloid, the small outer cycloid, and the sealing arc in the profile design based on the outer large outer cycloid, the outer small outer cycloid, and the sealing arc includes:

[0014] Based on the outer large cycloid of the pitch circle, the outer small cycloid of the pitch circle, the sealing arc, and the rotor meshing characteristics, the conjugate curves of the inner large cycloid of the pitch circle, the inner small cycloid of the pitch circle, and the sealing arc of the profile design are determined.

[0015] Optionally, determining the conjugate curves of the large outer cycloid, the small outer cycloid, and the sealing arc in the profile design based on the outer large outer cycloid, the outer small outer cycloid, the sealing arc, and the rotor meshing characteristics includes:

[0016] The coordinate system for the profile design is established using the rotor meshing characteristics described above.

[0017] Based on the outer large rounded epicycloid of the pitch circle and the coordinate system, determine the conjugate curve of the inner large rounded epicycloid of the pitch circle in the profile design;

[0018] Based on the small rounded cycloid outside the pitch circle and the coordinate system, determine the conjugate curve of the small rounded cycloid inside the pitch circle in the profile design;

[0019] Based on the sealing arc and the coordinate system, the conjugate curve of the sealing arc in the profile design is determined.

[0020] Optionally, obtaining the entire rotor profile of the profile design based on the outer large cycloid of the pitch circle, the outer small cycloid of the pitch circle, the sealing arc, the conjugate curve of the inner large cycloid of the pitch circle, the conjugate curve of the inner small cycloid of the pitch circle, the conjugate curve of the sealing arc, and the symmetry of the rotor profile includes:

[0021] Based on the outer large cycloid of the pitch circle, the outer small cycloid of the pitch circle, the sealing arc, the conjugate curve of the inner large cycloid of the pitch circle, the conjugate curve of the inner small cycloid of the pitch circle, and the conjugate curve of the sealing arc, the 1 / 4 rotor profile of the profile design is obtained.

[0022] Based on the symmetry of the 1 / 4 rotor profile and the rotor profile, the entire rotor profile of the profile design is obtained.

[0023] Secondly, embodiments of this application provide a rotor profile design device for a long cycloidal Roots pump with a sealing arc, the device comprising:

[0024] The acquisition module is used to acquire curves from the profile design.

[0025] The pitch circle outer information determination module is used to determine the pitch circle outer large rolling circle epicycloid, the pitch circle outer small rolling circle elongated epicycloid, and the sealing arc of the profile design based on the curve.

[0026] The pitch circle information determination module is used to determine the conjugate curves of the large rolling circle outer cycloid, the small rolling circle long cycloid, and the sealing arc in the profile design based on the large rolling circle outer cycloid, the small rolling circle long cycloid, and the sealing arc.

[0027] The rotor profile determination module is used to obtain the entire rotor profile of the profile design based on the outer large rolling circle epicycloid, the outer small rolling circle elongated epicycloid, the sealing arc, the conjugate curve of the inner large rolling circle epicycloid, the conjugate curve of the inner small rolling circle elongated epicycloid, the conjugate curve of the sealing arc, and the symmetry of the rotor profile.

[0028] Optionally, the acquisition module is used to acquire the pitch circle outer curve of the profile design and use the pitch circle outer curve as the curve of the profile design.

[0029] Optionally, the rotor profile determination module includes:

[0030] The preliminary determination unit is used to obtain the 1 / 4 rotor profile of the profile design based on the outer large rolling circle epicycloid, the outer small rolling circle elongated epicycloid, the sealing arc, the conjugate curve of the inner large rolling circle epicycloid, the conjugate curve of the inner small rolling circle elongated epicycloid, and the conjugate curve of the sealing arc.

[0031] The final determination unit is used to obtain the entire rotor profile of the profile design based on the symmetry of the 1 / 4 rotor profile and the rotor profile.

[0032] Thirdly, embodiments of this application provide a computer storage medium storing multiple instructions adapted for loading and execution of the above-described method steps by a processor.

[0033] Fourthly, embodiments of this application provide a terminal that may include: a processor and a memory; wherein the memory stores a computer program adapted to be loaded by the processor and executed by the above-described method steps.

[0034] The technical solutions provided in this application embodiment may include the following beneficial effects:

[0035] In this embodiment, the rotor profile design method for the long cycloidal Roots pump with sealing arc first acquires the profile design curve; then, based on the curve, the outer large cycloidal curve, outer small cycloidal curve, and sealing arc of the profile design are determined; next, based on the outer large cycloidal curve, outer small cycloidal curve, and sealing arc, the conjugate curves of the inner large cycloidal curve, inner small cycloidal curve, and sealing arc of the profile design are determined; finally, based on the symmetry of the outer large cycloidal curve, outer small cycloidal curve, sealing arc, inner large cycloidal curve, inner small cycloidal curve, and sealing arc, the entire rotor profile of the profile design is obtained. The rotor profile designed in this application has smooth connections between the curves of each segment, avoiding the formation of sharp points; the sealing arc increases the flow resistance between the Roots pump rotor and the wall, which can significantly improve the effective pumping speed, compression ratio and ultimate vacuum of the Roots pump; the rotor profile volume utilization rate can reach more than 55%, which is a significant advantage compared to the 50% of the standard cycloidal rotor profile.

[0036] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit the invention. Attached Figure Description

[0037] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0038] Figure 1 This is a schematic flowchart of a method for designing the rotor profile of a long cycloidal Roots pump with a sealing arc, provided in an embodiment of this application.

[0039] Figure 2 This is a schematic diagram of the rotor profile of a long cycloidal Roots pump with a sealing arc provided in an embodiment of this application.

[0040] Figure 3 This is a schematic diagram of the rotor profile analysis corresponding to the large round circle of a long cycloidal Roots pump rotor profile design method with a sealing arc provided in an embodiment of this application.

[0041] Figure 4 This is a schematic diagram illustrating the design analysis of a small rounded long cycloid rotor profile of a long cycloid Roots pump with a sealing arc provided in an embodiment of this application.

[0042] Figure 5 This is a schematic diagram illustrating the design method of the rotor profile of a long cycloidal Roots pump with a sealing arc provided in this application embodiment, showing the analysis of a small rounded long cycloidal profile.

[0043] Figure 6 This is a schematic diagram of the rotor profile of a long cycloidal Roots pump with a sealing arc provided in an embodiment of this application when δ1=γ0.

[0044] Figure 7 This is a schematic diagram of the rotor profile of a long cycloidal Roots pump with a sealing arc provided in an embodiment of this application when δ1>γ0.

[0045] Figure 8 This is a schematic diagram of the rotor profile of a long cycloidal Roots pump with a sealing arc provided in an embodiment of this application when δ1<γ0.

[0046] Figure 9 This is a schematic diagram of the coordinate system transformation in the conjugate curve of a rotor profile design method for a long cycloidal Roots pump with a sealing arc provided in an embodiment of this application.

[0047] Figure 10 This is a schematic diagram of the rotor profile under different large rolling radii R of a long cycloidal Roots pump with a sealing arc provided in the embodiments of this application;

[0048] Figure 11 This is a schematic diagram of the rotor profile under different large rounded profile angles θ1 of a long cycloidal Roots pump rotor profile design method with a sealing arc provided in the embodiments of this application;

[0049] Figure 12 This is a schematic diagram of rotor profiles under different long cycloidal small rolling radius r according to the rotor profile design method of a long cycloidal Roots pump with sealing arc provided in the embodiments of this application;

[0050] Figure 13 This is a schematic diagram of a rotor profile design device for a long cycloidal Roots pump with a sealing arc provided in an embodiment of this application;

[0051] Figure 14 This is a schematic diagram of a terminal provided in an embodiment of this application. Detailed Implementation

[0052] The following description and accompanying drawings fully illustrate specific embodiments of the invention to enable those skilled in the art to practice them.

[0053] It should be understood that the described embodiments are merely some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0054] In the following description, when referring to the accompanying drawings, the same numbers in different drawings denote the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Rather, they are merely examples of systems and methods consistent with some aspects of the invention as detailed in the appended claims.

[0055] In the description of this invention, it should be understood that the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Those skilled in the art can understand the specific meaning of these terms in this invention based on the specific circumstances. Furthermore, in the description of this invention, unless otherwise stated, "multiple" refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0056] The following will be combined with the appendix Figure 1 - Appendix Figure 12 This application provides a detailed description of a rotor profile design method for a long cycloidal Roots pump with a sealing arc, as provided in the embodiments of this application.

[0057] Please see Figure 1-12 This document presents a flowchart illustrating a method for designing the rotor profile of a long cycloidal Roots pump with a sealing arc, as described in an embodiment of this application. Figure 1-12 As shown, the method in this application embodiment may include the following steps:

[0058] This application relates to the design of a rotor profile for a long cycloidal Roots pump with a sealing arc, specifically a rotor profile composed of a long cycloidal line, a cycloidal line, and a sealing arc. Compared to standard involute, arc, and cycloidal rotor profiles, this rotor profile is that of a two-lobe Roots pump, consisting of a large cycloidal line outside the pitch circle, a small cycloidal line outside the pitch circle, and a sealing arc located outside the pitch circle; and conjugate curves of the large cycloidal line inside the pitch circle, the small cycloidal line inside the pitch circle, and the sealing arc (i.e., the small arc) located inside the pitch circle. The meshing characteristics of the rotor are used in solving for each conjugate curve located within the pitch circle. The long cycloid in the rotor profile achieves smooth connections between curve segments, avoiding sharp points; the sealing arc increases the flow resistance between the rotor and the wall, significantly improving the effective pumping speed, compression ratio, and ultimate vacuum of the Roots pump; while for a standard cycloid rotor profile, the gap between the rotor and the wall is minimized only at the highest point, resulting in significantly lower flow resistance than the novel rotor profile of this application. Furthermore, the volume utilization rate of a standard cycloid rotor is 50%, while the novel rotor profile can exceed 50%, reaching over 55%, demonstrating a clear advantage. Therefore, the novel rotor profile described in this application can reduce backflow during Roots pump operation, thereby improving parameters such as effective pumping speed, compression ratio, and ultimate vacuum.

[0059] The principle of this application is as follows:

[0060] like Figure 2 As shown, the rotor profile of the Roots pump is a centrally and axisymmetric curve, so in the actual solution, only 1 / 4 of the entire rotor profile needs to be solved. Figure 2 The profile located outside the pitch circle consists of three parts: AB is a large rounded cycloid, BC is a small rounded long cycloid, CD is a sealing arc, and the waist curve AG is the conjugate curve of AC.

[0061] S100, the curve for collecting profile design, including:

[0062] Collect the pitch circle outer curve of the profile design; use the pitch circle outer curve as the curve of the profile design.

[0063] This application proposes a rotor profile design using a top (outside the pitch circle) curve, which consists of a sealing arc, a cycloid, and a long cycloid.

[0064] S200, based on the curve, determine the outer large cycloid of the pitch circle, the outer small cycloid of the pitch circle, and the sealing arc of the profile design.

[0065] In the embodiments of this application, according to Figure 3 The design of the cycloid corresponding to the large roll circle outside the pitch circle, namely the large roll circle epicycloid (also known as the large roll circle rotor profile), is as follows:

[0066] Big round Ot The radius of the large rolling circle is R. Initially, it is tangent to the pitch circle at point A. When the large rolling circle rolls from point A to point M, the curve formed by AA′ is the epicycloid portion of the rotor profile corresponding to the large rolling circle. If the central angle of the large rolling circle is α, then the length of the arc A′M that the large rolling circle rolls over is Rα. If the central angle corresponding to the arc AM that the large rolling circle rolls over the pitch circle is θ, and the radius of the pitch circle is R0, then the length of the arc AM is R0θ. According to the characteristics of the cycloid, the lengths of the two arcs are equal. Therefore:

[0067]

[0068] If O t Let β be the angle between A′ and the horizontal line. Then β can be expressed as:

[0069]

[0070] In ΔO1O t In A′, OA′ can be represented as:

[0071]

[0072] in Let (x1, y1) be the coordinates of the coordinates. is ((R0+R)cos(θ+π / 4), (R0+R)sin(θ+π / 4)), The expression is (Rcosβ, -Rsinβ). Therefore, combining equations (2) and (3), It can be represented as:

[0073]

[0074] Formula (4) corresponds to the range of θ values ​​(0, θ1). When θ = θ1, the central angle α1 that the large rolling circle rolls through can be obtained from formula (1). At this time, A′ reaches Figure 2 Point B is shown.

[0075] At this point, AB is the outer largest rounded epicycloid outside the pitch circle.

[0076] In this embodiment, the design of the small rolled long cycloid outside the pitch circle, i.e., the long cycloid rotor profile, and the sealing arc is as follows:

[0077] according to Figure 4 and Figure 5 The design of a small, rolled cycloid located outside the pitch circle is carried out. When the large rolled circle rolls to position θ1, the design of the small, rolled cycloid is initiated, with the center of the small rolled circle at 0. r With radius r, connect O r B, at this time O r O t =Rr,O tIf B = R, then in ΔO r O t In B, by the Law of Cosines, if O r B = b, and its length can be expressed as:

[0078]

[0079] Let O r M and O r If the included angle between E and E is γ0, then γ0 = ∠O t O r B, in ΔO t O r Applying the law of cosines in B, γ0 can be expressed as:

[0080]

[0081] Let ∠MO r If B = δ0, then δ0 = π - γ0.

[0082] When the small, rounded cycloid rolls from the initial point B to any point B′, as follows: Figure 5 As shown, when the smaller round rolls through an angle δ, the arc length of the smaller round rolling through itself is NN′=δr, and the corresponding arc length of the pitch circle it rolls through is MN=R0θ. Since the two arcs are of equal length, δ can be expressed as…

[0083]

[0084] If O r Let ε be the angle between B′ and the horizontal line. Then ε can be expressed as:

[0085]

[0086] In ΔO1O r In B′, O1B′ can be represented as:

[0087]

[0088] in Let (x1, y1) be the coordinates of the coordinates. is ((R0+r)cos(θ+θ1+π / 4), (R0+r)sin(θ+θ1+π / 4)), Given (bcosε, bsinε), therefore, combining equations (8) and (9), It can be represented as:

[0089]

[0090] The range of θ is (θ1, θ1+θ2), and the central angle δ1 of the small rolling circle can be obtained by formula (7). The value of θ2 can be one of the following three cases:

[0091] (a) δ1=γ0, under this condition, when the small rolling circle rolls past δ1, B′ just reaches the rotor tip D, as shown. Figure 6 As shown, at this time, θ2=π / 4-θ1=γ0r / R0. Obviously, under this condition, it is impossible to form a sealing arc on the top of the rotor, which does not meet the design requirements.

[0092] (b) δ1>γ0, under this condition, when the small round ball rolls past γ0, point C(B′) and point O r Point O1 and point O2 are exactly on a straight line, such as Figure 7 As shown, at this time θ2=γ0r / R0. The profile CD adopts a sealing arc, with O1 as the center and R2=R0+r+b as the radius. A sealing arc can be designed on the top of the rotor, and its equation can be expressed as:

[0093]

[0094] The range of values ​​for θ is (0, θ3), and θ3 = π / 4 - θ1 - θ2.

[0095] according to Figure 7 Implement a sealing arc design. Figure 7 The sealing arc of the intermediate rotor is CD, with a corresponding central angle of θ3. The actual rotor profile has a sealing arc length of twice CD, with a corresponding central angle of 2θ3. Therefore, the flow conductance of the sealing arc can be expressed as...

[0096]

[0097] In the formula, C is the interstitial conductance, and η is the conductivity coefficient. Let be the average velocity of gas molecules, and l be the rotor length. Clearly, increasing the arc length R2θ3 corresponding to the gap reduces the conductance, thus decreasing backflow during Roots pump operation and improving parameters such as compression ratio and ultimate vacuum.

[0098] (c) δ1 < γ0. Under this condition, when the small rolling circle rolls past δ1, point N just reaches the vertex P of the pitch circle, as shown. Figure 8 As shown, at this time, θ2=π / 4-θ1=δ1r / R0. The profile CD adopts a pin-toothed arc with P as the center and PC as the radius, which cannot meet the requirements of a sealing arc.

[0099] As can be seen from the above, condition (b) satisfies the requirement of a sealing arc. In this case, BC is a small cycloid outside the pitch circle, and CD is a sealing arc.

[0100] S300, based on the outer large cycloid of the pitch circle, the outer small cycloid of the pitch circle, and the sealing arc, determine the conjugate curves of the inner large cycloid of the pitch circle, the inner small cycloid of the pitch circle, and the sealing arc of the profile design, including: based on the outer large cycloid of the pitch circle, the outer small cycloid of the pitch circle, the sealing arc, and the rotor meshing characteristics, determine the conjugate curves of the inner large cycloid of the pitch circle, the inner small cycloid of the pitch circle, and the sealing arc of the profile design, including:

[0101] Using the rotor meshing characteristics, a coordinate system for the profile design is established; based on the outer large roll circle epicycloid and the coordinate system, the conjugate curve of the inner large roll circle epicycloid of the profile design is determined; based on the outer small roll circle elongated epicycloid and the coordinate system, the conjugate curve of the inner small roll circle elongated epicycloid of the profile design is determined; based on the sealing arc and the coordinate system, the conjugate curve of the sealing arc of the profile design is determined.

[0102] In this embodiment, the design of the conjugate curve portion is as follows:

[0103] A conjugate curve (also known as a conjugate cycloid) can be described as a pair of smooth curves that maintain continuous tangential contact along a given contact method during motion, given a given motion law. When applying rotor meshing characteristics to solve for the profile corresponding to the rotor's conjugate curve, it is necessary to solve for the rotor's meshing angle φ. The meshing angle is the angle between the intersection of the normal to the meshing point and the pitch circle and the rotor center, and the coordinate y1. In an epicycloid, it is the angle between the line connecting the rolling circle center and the rotor center and the coordinate y1. Therefore, φ = π / 4 - θ.

[0104] like Figure 9 As shown, two coordinate systems S1 and S2 are established fixed to the rotor. According to the coordinate transformation relationship, the relationship between coordinate system S1(x1, y1) and S2(x2, y2) is as follows:

[0105]

[0106] Where d is the distance between the origins of coordinate systems S1 and S2, equation (13) is the conjugate curve part corresponding to the rotor epicycloid AC (AC is the large rolling epicycloid AB outside the pitch circle and the small rolling long epicycloid BC outside the pitch circle) (i.e. the conjugate curve of the large rolling epicycloid inside the pitch circle and the conjugate curve of the small rolling long epicycloid inside the pitch circle), where the variable φ is the meshing angle, and the value of (x1, y1) is determined by the circular arc equations (4), (10) and (11).

[0107] The above method can also be used to obtain the conjugate curve of the sealing arc.

[0108] S400, based on the outer large cycloid of the pitch circle, the outer small cycloid of the pitch circle, the sealing arc, the conjugate curve of the inner large cycloid of the pitch circle, the conjugate curve of the inner small cycloid of the pitch circle, the conjugate curve of the sealing arc, and the symmetry of the rotor profile, the entire rotor profile of the profile design is obtained, including:

[0109] Based on the outer large cycloid curve of the pitch circle, the outer small cycloid curve of the pitch circle, the sealing arc, the conjugate curve of the inner large cycloid curve of the pitch circle, the conjugate curve of the inner small cycloid curve of the pitch circle, and the conjugate curve of the sealing arc, the 1 / 4 rotor profile of the profile design is obtained; based on the symmetry of the 1 / 4 rotor profile and the rotor profile, the entire rotor profile of the profile design is obtained.

[0110] In the embodiments of this application, such as Figure 9 As shown, since the conjugate curve is located in the S2 coordinate system, it needs to be translated to S1 and rotated counterclockwise by π / 2. It forms a 1 / 4 rotor profile with the epicycloid AC and the sealing arc CD. Then, the entire rotor profile is obtained based on the symmetry of the rotor profile.

[0111] Figure 2 The entire rotor profile is obtained by symmetrically aligning the outer large cycloid of the pitch circle, the outer small cycloid of the pitch circle, the sealing arc, the conjugate curve of the inner large cycloid of the pitch circle, the conjugate curve of the inner small cycloid of the pitch circle, and the conjugate curve of the sealing arc according to the symmetry of the rotor profile and along the coordinate axes.

[0112] In summary, it can be found that the long cycloidal rotor profile (i.e. the entire rotor profile) described in this application consists of 4 independent variable parameters, which can generally be taken as the pitch circle radius R0, the large rolling circle radius R, the central angle θ1, and the long cycloidal small rolling circle radius r.

[0113] The rotor volume utilization factor of the Roots pump in this application embodiment is the ratio of the rotor cross-section to the rotor top circle area, which characterizes the space utilization degree of the Roots pump rotor.

[0114]

[0115] In equation (14), λ is the rotor volume utilization coefficient of the Roots pump, and B is the cross-sectional area of ​​the Roots pump rotor. If the rotor speed is n (r / min), the designed geometric pumping speed of the Roots pump is V. p (L / s), then the designed rotor length l (mm) is

[0116]

[0117] In this embodiment of the application, regarding the rotor cycloidal profile: following the above analysis steps, a Roots pump product with a pumping speed of 70L / s and a rotational speed of 3000r / min was designed, and the rotor pitch circle radius was R0 = 34mm. The changes in rotor profile parameters were designed and analyzed under different conditions of large rolling circle radius R, central angle θ1, and small rolling circle radius r of long cycloid.

[0118] Table 1 and Figure 10 The diagram shows the variation of rotor parameters under different large rolling radius R, given other variable parameters.

[0119] Table 1. Parameter variations of rotor profile under different large rolling radii R.

[0120] <![CDATA[θ1]]> π / 6 π / 6 π / 6 π / 6 π / 6 π / 6 π / 6 r(mm) 5 5 5 5 5 5 5 R(mm) 26 24 22 20 18 16 14 <![CDATA[R2(mm)]]> 55.47 55.27 55.03 54.73 54.36 53.88 53.23 <![CDATA[θ3(°)]]> 2.21 2.44 2.72 3.07 3.49 4.01 4.71 λ 0.5583 0.5573 0.5532 0.5498 0.466 0.5384 0.5304 l(mm) 129.72 130.89 133.02 135.31 137.96 142.58 148.22

[0121] As shown in Table 1, given other variable parameters, as the large rolling radius R decreases, the rotor top circle radius decreases, the volume utilization rate decreases, but the central angle corresponding to the sealing arc increases, and the rotor length increases. Therefore, appropriately reducing the large rolling radius is beneficial to enhancing the rotor's sealing capability.

[0122] Table 2 and Figure 11 The changes in rotor parameters under different large rounding angles θ1 are shown, given other variable parameters.

[0123] Table 2. Parameter variations of rotor profile under different large roundness angles θ1

[0124]

[0125]

[0126] As shown in Table 2, given other variable parameters, as the large rolling angle θ1 decreases, the rotor top circle radius decreases, the volume utilization rate decreases, but the central angle corresponding to the sealing arc increases, and the rotor length increases. Therefore, appropriately reducing the large rolling angle is beneficial to enhancing the rotor's sealing capability.

[0127] Table 3 and Figure 12 The changes in rotor parameters under different long cycloid small rolling radius r are shown, given other variable parameters.

[0128] Table 3. Parameter variations of rotor profile under different small cycloidal radii r.

[0129] <![CDATA[θ1]]> π / 6 π / 6 π / 6 π / 6 π / 6 R(mm) 20 20 20 20 20 r(mm) 2 3 4 5 6 <![CDATA[R2(mm)]]> 52.46 53.16 53.91 54.73 55.61 <![CDATA[θ3(°)]]> 10.84 8.46 5.87 3.07 0.03 λ 0.5170 0.5278 0.5394 0.5498 0.5498 l(mm) 156.62 149.39 142.10 135.31 135.31

[0130] As shown in Table 3, given other variable parameters, with the increase of the small cycloidal radius r, the rotor top circle radius increases, the volume utilization rate increases, but the central angle corresponding to the sealing arc decreases, and the rotor length decreases. Therefore, appropriately reducing the small cycloidal radius is beneficial to enhancing the rotor's sealing capability.

[0131] In summary, given the rotor pitch circle radius R0, increasing the large rolling radius R, the large rolling profile angle θ1, and the long cycloidal small rolling radius r is beneficial for increasing rotor volume utilization. However, it reduces the length of the sealing arc, thus decreasing sealing performance. Therefore, in actual rotor design, it is necessary to select appropriate large rolling radius R, large rolling profile angle θ1, and long cycloidal small rolling radius r to ensure that the rotor has a certain length of sealing arc while meeting the rotor volume utilization requirements. This reduces backflow during Roots pump operation and improves the overall pumping speed, ultimate vacuum, and compression ratio, among other core parameters.

[0132] The parameters for a Roots pump designed with a geometric pumping speed of 70 L / s and a rotational speed of 3000 r / min are as follows:

[0133] Pitch circle radius R0 = 34 mm; small rolling circle radius r = 5 mm; large rolling circle radius R = 26 mm; top circle radius (sealing arc radius) R2 = 55.47 mm; central angle θ1 = π / 6; rotor volume utilization rate λ = 55.83%; rotor length l = 130 mm.

[0134] This application addresses the existing cycloidal standard profile of Roots pump rotors by designing a long cycloidal Roots pump rotor profile with a sealing arc, based on the standard cycloidal profile and incorporating the characteristics of a long cycloidal profile and a sealing arc. This rotor profile consists of a large outer cycloidal curve outside the pitch circle, a small outer cycloidal curve outside the pitch circle, and a sealing arc, as well as conjugate curves within the pitch circle. This rotor profile has four independent variable parameters, while the standard cycloidal rotor profile has only one. The large outer cycloidal curve outside the pitch circle, the small outer cycloidal curve outside the pitch circle, and the sealing arc... The rotor profile (the sealing arc) is smoothly connected to the conjugate curves within the pitch circle, without sharp points or abrupt changes. The minimum clearance between the rotor and the wall is a circular arc. According to the relationship between flow resistance and clearance length, the magnitude of flow resistance is proportional to the length of the clearance arc. Therefore, this rotor profile (the sealing arc) can significantly increase the flow resistance between the Roots pump rotor and the wall, thereby reducing backflow during Roots pump operation and significantly improving effective pumping speed, compression ratio, and ultimate vacuum. The rotor profile volume utilization rate can reach over 55%, which is significantly better than the 50% of the standard cycloidal rotor profile.

[0135] In this embodiment, the rotor profile design method for the long cycloidal Roots pump with sealing arc first acquires the profile design curve; then, based on the curve, the outer large cycloidal curve, outer small cycloidal curve, and sealing arc of the profile design are determined; next, based on the outer large cycloidal curve, outer small cycloidal curve, and sealing arc, the conjugate curves of the inner large cycloidal curve, inner small cycloidal curve, and sealing arc of the profile design are determined; finally, based on the symmetry of the outer large cycloidal curve, outer small cycloidal curve, sealing arc, inner large cycloidal curve, inner small cycloidal curve, and sealing arc, the entire rotor profile of the profile design is obtained. The rotor profile designed in this application has smooth connections between the curves of each segment, avoiding the formation of sharp points; the sealing arc increases the flow resistance between the Roots pump rotor and the wall, which can significantly improve the effective pumping speed, compression ratio and ultimate vacuum of the Roots pump; the rotor profile volume utilization rate can reach more than 55%, which is a significant advantage compared to the 50% of the standard cycloidal rotor profile.

[0136] The following are embodiments of the apparatus of the present invention, which can be used to execute embodiments of the method of the present invention. For details not disclosed in the embodiments of the apparatus of the present invention, please refer to the embodiments of the method of the present invention.

[0137] Please see Figure 13 This illustration shows a schematic diagram of a rotor profile design device for a long cycloidal Roots pump with a sealing arc, provided by an exemplary embodiment of the present invention. The device includes: a data acquisition module 10, a pitch circle outer information determination module 20, a pitch circle inner information determination module 30, and a rotor profile determination module 40.

[0138] Acquisition module 10 is used to acquire curves from the profile design;

[0139] The pitch circle outer information determination module 20 is used to determine the pitch circle outer large rolling circle epicycloid, the pitch circle outer small rolling circle elongated epicycloid, and the sealing arc of the profile design based on the curve.

[0140] The pitch circle information determination module 30 is used to determine the conjugate curves of the large rolling circle outer cycloid, the small rolling circle long cycloid, and the sealing arc in the profile design based on the large rolling circle outer cycloid, the small rolling circle long cycloid, and the sealing arc.

[0141] The rotor profile determination module 40 is used to obtain the entire rotor profile of the profile design based on the outer large rolling circle epicycloid, the outer small rolling circle elongated epicycloid, the sealing arc, the conjugate curve of the inner large rolling circle epicycloid, the conjugate curve of the inner small rolling circle elongated epicycloid, the conjugate curve of the sealing arc, and the symmetry of the rotor profile.

[0142] In one possible implementation, the acquisition module 10 is used to acquire the pitch circle outer curve of the profile design and use the pitch circle outer curve as the curve of the profile design.

[0143] In one possible implementation, the rotor profile determination module 40 includes:

[0144] The preliminary determination unit is used to obtain the 1 / 4 rotor profile of the profile design based on the outer large rolling circle epicycloid, the outer small rolling circle elongated epicycloid, the sealing arc, the conjugate curve of the inner large rolling circle epicycloid, the conjugate curve of the inner small rolling circle elongated epicycloid, and the conjugate curve of the sealing arc.

[0145] The final determination unit is used to obtain the entire rotor profile of the profile design based on the symmetry of the 1 / 4 rotor profile and the rotor profile.

[0146] It should be noted that the above-described embodiment of the long cycloidal Roots pump rotor profile design device with sealing arc is only an example of the above-described division of functional modules when implementing the long cycloidal Roots pump rotor profile design method with sealing arc. In practical applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the equipment can be divided into different functional modules to complete all or part of the functions described above. In addition, the above-described embodiment of the long cycloidal Roots pump rotor profile design device with sealing arc and the embodiment of the long cycloidal Roots pump rotor profile design method belong to the same concept, and the implementation process is detailed in the method embodiment, which will not be repeated here.

[0147] The sequence numbers of the embodiments in this application are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0148] The rotor profile design device for the long cycloidal Roots pump with sealing arc first acquires the profile design curve; then, based on the curve, it determines the outer large cycloidal curve, outer small cycloidal curve, and sealing arc of the profile design; next, based on the outer large cycloidal curve, outer small cycloidal curve, and sealing arc, it determines the conjugate curves of the inner large cycloidal curve, inner small cycloidal curve, and sealing arc of the profile design; finally, based on the symmetry of the outer large cycloidal curve, outer small cycloidal curve, sealing arc, inner large cycloidal curve, inner small cycloidal curve, and sealing arc, it obtains the entire rotor profile of the profile design. The rotor profile designed in this application has smooth connections between the curves of each segment, avoiding the formation of sharp points; the sealing arc increases the flow resistance between the Roots pump rotor and the wall, which can significantly improve the effective pumping speed, compression ratio and ultimate vacuum of the Roots pump; the rotor profile volume utilization rate can reach more than 55%, which is a significant advantage compared to the 50% of the standard cycloidal rotor profile.

[0149] The present invention also provides a computer-readable medium having program instructions stored thereon, which, when executed by a processor, implement the rotor profile design method for a long cycloidal Roots pump with a sealing arc provided in the above-described method embodiments.

[0150] The present invention also provides a computer program product containing instructions that, when run on a computer, cause the computer to execute the rotor profile design method of the long cycloidal Roots pump with sealing arc described in the above-described method embodiments.

[0151] Please see Figure 14 This is a schematic diagram of the structure of a terminal provided in an embodiment of this application. Figure 14 As shown, terminal 1000 may include: at least one processor 1001, at least one network interface 1004, user interface 1003, memory 1005, and at least one communication bus 1002.

[0152] The communication bus 1002 is used to realize the connection and communication between these components.

[0153] The user interface 1003 may include a display screen and a camera. Optionally, the user interface 1003 may also include a standard wired interface and a wireless interface.

[0154] The network interface 1004 may optionally include a standard wired interface or a wireless interface (such as a Wi-Fi interface).

[0155] The processor 1001 may include one or more processing cores. The processor 1001 connects to various parts within the terminal 1000 using various interfaces and lines, and performs various functions and processes data by running or executing instructions, programs, code sets, or instruction sets stored in the memory 1005, and by calling data stored in the memory 1005. Optionally, the processor 1001 may be implemented using at least one hardware form of Digital Signal Processing (DSP), Field-Programmable Gate Array (FPGA), or Programmable Logic Array (PLA). The processor 1001 may integrate one or a combination of several of the following: Central Processing Unit (CPU), Graphics Processing Unit (GPU), and modem. The CPU primarily handles the operating system, user interface, and applications; the GPU is responsible for rendering and drawing the content required for display; and the modem handles wireless communication. It is understood that the modem may also not be integrated into the processor 1001 and may be implemented as a separate chip.

[0156] The memory 1005 may include random access memory (RAM) or read-only memory. Optionally, the memory 1005 may include a non-transitory computer-readable storage medium. The memory 1005 can be used to store instructions, programs, code, code sets, or instruction sets. The memory 1005 may include a program storage area and a data storage area, wherein the program storage area may store instructions for implementing an operating system, instructions for at least one function (such as touch function, sound playback function, image playback function, etc.), instructions for implementing the above-described method embodiments, etc.; the data storage area may store data involved in the above-described method embodiments, etc. Optionally, the memory 1005 may also be at least one storage device located remotely from the aforementioned processor 1001. Figure 14 As shown, the memory 1005, which serves as a computer storage medium, may include an operating system, a network communication module, a user interface module, and an application program for designing the rotor profile of a long cycloidal Roots pump with a sealed arc.

[0157] exist Figure 14In the terminal 1000 shown, the user interface 1003 is mainly used to provide an input interface for the user and to obtain the user's input data; while the processor 1001 can be used to call the application program for the design of the rotor profile of the long cycloidal Roots pump with sealing arc stored in the memory 1005, and specifically perform the following operations:

[0158] The curves in the profile design are collected;

[0159] Based on the curve, determine the outer large rounded cycloid of the pitch circle, the outer small rounded cycloid of the pitch circle, and the sealing arc of the profile design;

[0160] Based on the outer large cycloid of the pitch circle, the outer small cycloid of the pitch circle, and the sealing arc, determine the conjugate curves of the inner large cycloid of the pitch circle, the inner small cycloid of the pitch circle, and the sealing arc of the profile design.

[0161] Based on the symmetry of the outer large cycloid of the pitch circle, the outer small cycloid of the pitch circle, the sealing arc, the conjugate curve of the inner large cycloid of the pitch circle, the conjugate curve of the inner small cycloid of the pitch circle, the conjugate curve of the sealing arc, and the rotor profile, the entire rotor profile of the profile design is obtained.

[0162] In one embodiment, when the processor 1001 executes the curve of the acquisition profile design, it specifically performs the following operations:

[0163] Acquire the pitch circle outer curve of the profile design;

[0164] The outer curve of the pitch circle is used as the curve for the profile design.

[0165] In one embodiment, when the processor 1001 executes the step of determining the conjugate curves of the inner large roll circle epicycloid, the inner small roll circle elongated cycloid, and the sealing arc of the profile design based on the outer large roll circle epicycloid, the outer small roll circle elongated cycloid, and the sealing arc, the processor 1001 specifically performs the following operations:

[0166] Based on the outer large cycloid of the pitch circle, the outer small cycloid of the pitch circle, the sealing arc, and the rotor meshing characteristics, the conjugate curves of the inner large cycloid of the pitch circle, the inner small cycloid of the pitch circle, and the sealing arc of the profile design are determined.

[0167] In one embodiment, when processor 1001 executes the step of determining the conjugate curves of the large pitch circle outer cycloid, the small pitch circle outer elongated cycloid, the sealing arc, and the sealing arc of the profile design based on the large pitch circle outer cycloid, the small pitch circle inner elongated cycloid, the sealing arc, and the rotor meshing characteristics, it specifically performs the following operations:

[0168] The coordinate system for the profile design is established using the rotor meshing characteristics described above.

[0169] Based on the outer large rounded epicycloid of the pitch circle and the coordinate system, determine the conjugate curve of the inner large rounded epicycloid of the pitch circle in the profile design;

[0170] Based on the small rounded cycloid outside the pitch circle and the coordinate system, determine the conjugate curve of the small rounded cycloid inside the pitch circle in the profile design;

[0171] Based on the sealing arc and the coordinate system, the conjugate curve of the sealing arc in the profile design is determined.

[0172] In one embodiment, when processor 1001 executes the step of obtaining the entire rotor profile of the profile design based on the outer large cycloid of the pitch circle, the outer small cycloid of the pitch circle, the sealing arc, the conjugate curve of the inner large cycloid of the pitch circle, the conjugate curve of the inner small cycloid of the pitch circle, the conjugate curve of the sealing arc, and the symmetry of the rotor profile, it specifically performs the following operations:

[0173] Based on the outer large cycloid of the pitch circle, the outer small cycloid of the pitch circle, the sealing arc, the conjugate curve of the inner large cycloid of the pitch circle, the conjugate curve of the inner small cycloid of the pitch circle, and the conjugate curve of the sealing arc, the 1 / 4 rotor profile of the profile design is obtained.

[0174] Based on the symmetry of the 1 / 4 rotor profile and the rotor profile, the entire rotor profile of the profile design is obtained.

[0175] The method for designing the rotor profile of a long cycloidal Roots pump with a sealing arc involves first acquiring the profile design curve; then, based on the curve, determining the outer large cycloidal curve, outer small cycloidal curve, and sealing arc of the profile design; next, based on the outer large cycloidal curve, outer small cycloidal curve, and sealing arc, determining the conjugate curves of the inner large cycloidal curve, inner small cycloidal curve, and sealing arc of the profile design; finally, based on the symmetry of the outer large cycloidal curve, outer small cycloidal curve, sealing arc, inner large cycloidal curve, inner small cycloidal curve, and sealing arc, obtaining the entire rotor profile of the profile design. The rotor profile designed in this application has smooth connections between the curves of each segment, avoiding the formation of sharp points; the sealing arc increases the flow resistance between the Roots pump rotor and the wall, which can significantly improve the effective pumping speed, compression ratio and ultimate vacuum of the Roots pump; the rotor profile volume utilization rate can reach more than 55%, which is a significant advantage compared to the 50% of the standard cycloidal rotor profile.

[0176] Those skilled in the art will understand that implementing all or part of the processes in the above embodiments can be accomplished by a computer program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. The storage medium can be a magnetic disk, optical disk, read-only memory, or random access memory, etc.

[0177] The above-disclosed embodiments are merely preferred embodiments of this application and should not be construed as limiting the scope of this application. Therefore, any equivalent variations made in accordance with the claims of this application shall still fall within the scope of this application.

Claims

1. A method for designing the rotor profile of a long cycloidal Roots pump with a sealing arc, characterized in that, Includes the following steps: The curves for the acquisition profile design include: Acquire the pitch circle outer curve of the profile design; The outer curve of the pitch circle is used as the curve for the profile design; Based on the curve, determine the outer large rounded cycloid of the pitch circle, the outer small rounded cycloid of the pitch circle, and the sealing arc of the profile design; Based on the outer large cycloid of the pitch circle, the outer small cycloid of the pitch circle, and the sealing arc, determine the conjugate curves of the inner large cycloid of the pitch circle, the inner small cycloid of the pitch circle, and the sealing arc of the profile design, including: Based on the outer large cycloid of the pitch circle, the outer small cycloid of the pitch circle, the sealing arc, and the rotor meshing characteristics, the conjugate curves of the inner large cycloid of the pitch circle, the inner small cycloid of the pitch circle, and the sealing arc of the profile design are determined, including: The coordinate system for the profile design is established using the rotor meshing characteristics described above. Based on the outer large rounded epicycloid of the pitch circle and the coordinate system, determine the conjugate curve of the inner large rounded epicycloid of the pitch circle in the profile design; Based on the small rounded cycloid outside the pitch circle and the coordinate system, determine the conjugate curve of the small rounded cycloid inside the pitch circle in the profile design; Based on the sealing arc and the coordinate system, determine the conjugate curve of the sealing arc in the profile design; Based on the symmetry of the outer large cycloid of the pitch circle, the outer small cycloid of the pitch circle, the sealing arc, the conjugate curve of the inner large cycloid of the pitch circle, the conjugate curve of the inner small cycloid of the pitch circle, the conjugate curve of the sealing arc, and the rotor profile, the entire rotor profile of the profile design is obtained, including: Based on the outer large cycloid of the pitch circle, the outer small cycloid of the pitch circle, the sealing arc, the conjugate curve of the inner large cycloid of the pitch circle, the conjugate curve of the inner small cycloid of the pitch circle, and the conjugate curve of the sealing arc, the 1 / 4 rotor profile of the profile design is obtained. Based on the symmetry of the 1 / 4 rotor profile and the rotor profile, the entire rotor profile of the profile design is obtained.

2. A rotor profile design device for a long cycloidal Roots pump with a sealing arc, characterized in that, include: The acquisition module is used to acquire curves from the profile design. The acquisition module is used to acquire the pitch circle outer curve of the profile design and use the pitch circle outer curve as the curve of the profile design. The pitch circle outer information determination module is used to determine the pitch circle outer large rolling circle epicycloid, the pitch circle outer small rolling circle elongated epicycloid, and the sealing arc of the profile design based on the curve. The pitch circle information determination module is used to determine the conjugate curves of the large rolling circle outer cycloid, the small rolling circle long cycloid, and the sealing arc in the profile design based on the large rolling circle outer cycloid, the small rolling circle long cycloid, and the sealing arc. The rotor profile determination module is used to obtain the entire rotor profile of the profile design based on the outer large rolling circle epicycloid, the outer small rolling circle elongated epicycloid, the sealing arc, the conjugate curve of the inner large rolling circle epicycloid, the conjugate curve of the inner small rolling circle elongated epicycloid, the conjugate curve of the sealing arc, and the symmetry of the rotor profile. The rotor profile determination module includes: The preliminary determination unit is used to obtain the 1 / 4 rotor profile of the profile design based on the outer large rolling circle epicycloid, the outer small rolling circle elongated epicycloid, the sealing arc, the conjugate curve of the inner large rolling circle epicycloid, the conjugate curve of the inner small rolling circle elongated epicycloid, and the conjugate curve of the sealing arc. The final determination unit is used to obtain the entire rotor profile of the profile design based on the symmetry of the 1 / 4 rotor profile and the rotor profile.

3. A computer storage medium, characterized in that, The computer storage medium stores a plurality of instructions adapted for loading by a processor and executing the method steps of claim 1.

4. A terminal, characterized in that, include: A processor and a memory; wherein the memory stores a computer program adapted to be loaded by the processor and to execute the method steps of claim 1.

Images