CN114607598B - Roots rotor with gradual change shape coefficient and design method thereof - Google Patents

Roots rotor with gradual change shape coefficient and design method thereof Download PDF

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Publication number
CN114607598B
CN114607598B CN202011445831.1A CN202011445831A CN114607598B CN 114607598 B CN114607598 B CN 114607598B CN 202011445831 A CN202011445831 A CN 202011445831A CN 114607598 B CN114607598 B CN 114607598B
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rotor
shape factor
factor
function
roots
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CN114607598A (en
Inventor
谢元华
高满堂
王光玉
王云
刘坤
钟瑞
王桂鹏
巴要帅
巴德纯
蔡旭
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Sky Development Co ltd Chinese Academy Of Sciences
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Sky Development Co ltd Chinese Academy Of Sciences
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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C18/00—Rotary-piston pumps specially adapted for elastic fluids
    • F04C18/08—Rotary-piston pumps specially adapted for elastic fluids of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing
    • F04C18/12—Rotary-piston pumps specially adapted for elastic fluids of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of other than internal-axis type
    • F04C18/126—Rotary-piston pumps specially adapted for elastic fluids of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of other than internal-axis type with radially from the rotor body extending elements, not necessarily co-operating with corresponding recesses in the other rotor, e.g. lobes, Roots type
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C18/00—Rotary-piston pumps specially adapted for elastic fluids
    • F04C18/08—Rotary-piston pumps specially adapted for elastic fluids of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing
    • F04C18/082—Details specially related to intermeshing engagement type pumps
    • F04C18/084—Toothed wheels
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F30/00—Computer-aided design [CAD]
    • G06F30/10—Geometric CAD
    • G06F30/17—Mechanical parametric or variational design
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C2240/00—Components
    • F04C2240/20—Rotors

Abstract

The invention relates to the field of vacuum Roots pumps, in particular to a Roots rotor with a gradual change shape coefficient and a design method thereof, wherein the shape coefficient of the rotor gradually changes along the axial direction, the change trend is a continuous function, the change trend at least comprises one of gradual decrease and gradual increase, the maximum shape coefficient of the rotor is a theoretical maximum Cmax, the waist of the rotor is a concave part A, the outer side of the rotor is a top part B, and when two rotors are matched, the top part B of one rotor is embedded into the concave part A of the other rotor. The shape coefficient of the rotor gradually changes along the axial direction, and a large shape coefficient section and a small shape coefficient section are formed, wherein the rotor of the large shape coefficient section can reach the theoretical maximum value of the shape coefficient, so that the volume utilization coefficient and the pumping speed of the Roots pump are obviously improved, and the rotor of the small shape coefficient section can serve as a rib plate of the rotor of the large shape coefficient section, so that the whole rotor is reinforced.

Description

Roots rotor with gradual change shape coefficient and design method thereof
Technical Field
The invention relates to the field of vacuum Roots pumps, in particular to a Roots rotor with gradual change shape coefficients and a design method thereof.
Background
The shape factor of the roots rotor is a main basis for the design of the roots rotor, the size of the roots rotor is determined by the tooth top radius and the pitch radius, and as shown in fig. 14, the shape factor is calculated as follows:
in the above formula: c is a shape factor; rm is the radius of the addendum circle; r is the pitch radius or half the distance of the rotor center distance.
The geometry of a conventional Roots rotor is uniform across its cross-section perpendicular to its axis, and because its line equation is constant in the axial direction, the shape factor C of a conventional Roots rotor is generally constant. According to the difference of the profile equation of the Roots rotor, there is a theoretical maximum value and a theoretical minimum value of the shape factor of the Roots rotor, namely Cmax and Cmin respectively.
The maximum shape factor Cmax and the minimum shape factor Cmin are generally not used in designing the roots rotor. Although the larger the value of the shape factor C is, the larger the corresponding volume utilization factor is, the higher the pumping speed can be, but the too large value of the shape factor C can lead to the insufficient root strength of the rotor due to the too small root width, in addition, the too large value of the shape factor C can lead to the whole rotor being in a slender shape, and the rotor can shake if the axial thickness of the rotor is smaller during rotation, so as to scrape the pump wall; if the value of the shape factor C is too small, it is obvious that the smaller the volume utilization factor is, the lower the pumping efficiency of the rotor is, and the rotor is not generally utilized. Therefore, the shape coefficients C ε [ cmin+δ1, cmax- δ2] and δ1 and δ2 ε (0, 2) are generally set when designing the rotor, and the Roots rotor in the prior art cannot effectively utilize the theoretical maximum value of the shape coefficients to develop and design the product.
Disclosure of Invention
The invention aims to provide a Roots rotor with a gradual change shape coefficient and a design method thereof, wherein the shape coefficient of the rotor gradually changes along the axial direction, so that the volume utilization coefficient and the pumping speed of the Roots pump are obviously improved.
The aim of the invention is realized by the following technical scheme:
a Roots rotor having a gradual shape factor, the shape factor of the rotor gradually changing along an axial direction, the trend of the change being a continuous function, and the trend of the change including at least one of gradually decreasing and gradually increasing.
The waist of the rotor is a concave part A, the outer side of the rotor is a top part B, and when the two rotors are matched, the top part B of one rotor is arranged in the concave part A of the other rotor.
A method of designing a roots rotor having a progressive form factor according to the present invention, comprising the steps of:
step one: determining the relation between the theoretical pumping speed Sth' of the designed vacuum pump and the rotor thickness L, the tooth top circle radius Rm and the volume utilization coefficient lambda;
step two: determining an influence factor of the theoretical pumping speed under the condition that the addendum circle radius Rm is a variable, wherein the influence factor is the average addendum circle radius of the rotorAnd->The rotor achieves a greater theoretical pumping speed than conventional rotor designs,/>A shape factor dependent function C (L);
step three: defining a function type of the shape factor and obtaining a function C (L), and a trend of change of the shape factor in a direction along the axial direction includes at least one of gradually decreasing and gradually increasing;
step four: determining a molded line equation of the rotor;
step five: generating a three-dimensional model of the rotor;
in step one, the theoretical pumping speed Sth (L/s) of a conventional roots rotor is as follows:
in the formula (1), rm is the radius (mm) of a tooth top circle, L is the thickness (mm) of a rotor, lambda is a volume utilization coefficient, and n is the rotating speed (r/min);
the Roots rotor theoretical pumping speed Sth' (L/s) with a gradual shape factor is as follows:
in the above formula (2), sth' is the theoretical pumping speed of the rotor when the addendum circle radius Rm is a variable,the rotor average addendum circle radius (mm) in the case that addendum circle radius Rm is a variable;
from the above formulas (1) and (2), it can be seen that the conventional Roots rotor is the same as the Roots rotor having a gradient shape factor, and the theoretical pumping speed is related to the tip circle radius, the rotor thickness, and the volume utilization factor.
In the second step:
since the pump chamber volume and the rotor rotational speed are the same, it can be seen from the above formulas (1) and (2):
the magnitudes of the conventional rotor theoretical pumping speeds Sth and Rm are roots rotor theoretical pumping speeds Sth' with gradual shape coefficients, which depend on the magnitude of the volume utilization coefficient lambda;
the calculation formula of the volume utilization coefficient lambda is:
in the above formula (4), V Rotor For rotor volume, V Cavity body Is the pump chamber volume.
As can be seen from the above formula (4), V Cavity body The magnitude of the volume utilization coefficient lambda is fixed and depends only on V Rotor I.e. only on the size of the rotor form factor C;
the conventional rotor form factor is:
the rotor shape factor in the case where the tip circle radius Rm is a variable is:
the center distance R is known, if:
then:
whileFunction C (L) depending on the shape factor:
the trend of the change of the shape factor in the direction along the axial direction includes at least one of gradually decreasing and gradually increasing, and forms a large shape factor section and a small shape factor section, the small shape factor section playing a reinforcing role for the entire rotor.
The invention has the advantages and positive effects that:
1. the rotor of the invention has the shape coefficient gradually changing along the axial direction and at least comprises one of gradually decreasing and gradually increasing, thereby forming a large shape coefficient section and a small shape coefficient section, wherein the rotor of the large shape coefficient section can reach the theoretical maximum value of the shape coefficient, so the volume utilization coefficient and the pumping speed of the Roots pump are obviously improved, and the rotor of the small shape coefficient section can serve as a rib plate of the rotor of the large shape coefficient section to play a role in strengthening the whole rotor.
2. The waist of the rotor is the concave part A, and the top B of the outer side of the rotor matched with the concave part A can be embedded into the concave part A, and as the inlet and outlet of the Roots pump cavity are generally arranged in the middle of the rotor, the funnel-shaped concave cavity formed by the waist and the top in a matched manner is beneficial to the gas flow of the two sides of the rotor when the rotor rotates, so that the Roots rotor with gradually changed shape coefficients can improve the gas flow.
Drawings
Figure 1 is a schematic cross-sectional variation of a two-lobe progressive form factor rotor embodiment of the present invention,
figure 2 is a three view of the two-lobe progressive form factor rotor of figure 1,
figure 3 is a schematic perspective view of the two-lobe progressive form factor rotor of figure 2,
figure 4 is a schematic view of the variation of the rotor form factor of figure 1 along the axial direction,
figure 5 is a schematic diagram of the rotor of figure 1 in comparison to a conventional rotor form factor,
FIG. 6 is a graph showing the comparison of the rotor volume utilization coefficients of the rotor of FIG. 1 with those of a conventional rotor
Figure 7 is a three-view of a two-lobe progressive (or progressive) form factor rotor embodiment of the present invention,
figure 8 is a schematic perspective view of the two-lobe progressive reduction (or progressive increase) form factor rotor of figure 7,
figure 9 is a three view of a two-lobe progressive addition form factor rotor embodiment of the present invention,
figure 10 is a schematic perspective view of the two-lobe progressive decrease and progressive increase form factor rotor of figure 9,
figure 11 is a three view of a four-lobe progressive form factor rotor embodiment of the invention,
figure 12 is a schematic perspective view of the four-lobe progressive form factor rotor of figure 11,
figure 13 is an assembled schematic view of the four-lobe progressive form factor rotor of figure 12,
fig. 14 is a schematic view of a prior art rotor profile.
Detailed Description
The invention is described in further detail below with reference to the accompanying drawings.
As shown in fig. 1 to 13, the shape factor of the Roots rotor of the present invention gradually changes along the axial direction, and the shape factor is a continuous function along the axial direction, the molded line of the Roots rotor is composed of different geometric line segments, the geometric form of the line segments can be one or more of circular arc lines, elliptical arc lines, cycloid lines, involute lines and straight lines, and the number of the blades of the rotor can be one of 2 blades, 3 blades, 4 blades or 5 blades.
The variation trend of the shape factor of the rotor in the axial direction at least comprises one of gradual decrease and gradual increase, wherein fig. 1 and fig. 7-9 show gradual increase, keep unchanged, gradual decrease forms, fig. 3-4 show gradual decrease (or gradual increase) forms, and fig. 5-6 show gradual decrease, keep unchanged, gradual increase forms. When designing the rotor according to a specific working condition, the size of the radius of the tip circle of the specific part of the rotor can be controlled by controlling the axial change trend of the shape coefficient, so that the working condition is met; under the condition of reasonable design, the shape coefficient of the rotor is higher than that of a conventional rotor, so that the volume utilization coefficient of the rotor is improved, and the pumping speed of the vacuum pump is further improved.
The design method of the invention comprises the following steps:
step one: and determining the relation between the theoretical pumping speed of the designed vacuum pump and the tooth top circle radius, the rotor thickness and the volume utilization coefficient lambda.
The following assumptions are first made:
1. the rotor of the invention and the conventional rotor have the tooth top radius equal to the radius of the pump cavity for accommodating the rotor, namely, the clearance between the tooth top surface and the respective cavity is zero.
2. The axial thickness L of the pump cavity of the rotor is equal to the thickness of the rotor, namely, the clearance between the side walls of the rotor and the cavity is zero.
3. The pitch circle radius of the rotor is equal to that of a conventional rotor, namely the center distance of the rotor and the conventional rotor is the same.
4. The rotor of the present invention has the same pump chamber volume as a conventional rotor.
5. The rotor of the present invention has the same motor speed as a conventional rotor.
6. The rotor of the present invention has the same number of rotor blades as a conventional rotor.
The theoretical pumping speed Sth (L/s) of a conventional roots rotor is as follows:
the above formula (1) is known in the art, wherein Rm is the addendum circle radius (mm), L is the rotor thickness (mm), lambda is the volume utilization factor, and n is the rotational speed (r/min).
The theoretical pumping speed Sth' (L/s) of the rotor of the present invention is as follows:
in the above formula (2), sth' is the theoretical pumping speed of the rotor under the condition that the addendum circle radius Rm is a variable, namely the theoretical pumping speed of the rotor of the invention,the rotor average tip circle radius (mm) in the case where the tip circle radius Rm is a variable.
It can be seen that the conventional Roots rotor is identical to the rotor of the present invention, and the theoretical pumping speed is related to the addendum circle radius, the rotor thickness and the volume utilization coefficient.
Step two: and determining an influence factor of the theoretical pumping speed under the condition that the addendum circle radius Rm is a variable.
According to the 4 th and 5 th points assumed in the first step, since the pump cavity volume and the rotor rotation speed are the same, the following steps are adopted:
the magnitudes of Sth and Sth' are therefore both dependent on the magnitude of the volume utilization coefficient lambda.
The calculation formula of the volume utilization coefficient lambda is as follows:
in the above formula (4), V Rotor For rotor volume, V Cavity body Is the pump chamber volume.
As can be seen from the above formula (4), V Cavity body The magnitude of the volume utilization coefficient lambda is fixed and depends only on V Rotor I.e. only on the size of the rotor form factor C.
Whereas conventional rotor form factors are:
the rotor shape factor in the case where the tip circle radius Rm is a variable is:
the center-to-center distance is generally known at design time, i.e., R is known, if:
then:
it follows that the theoretical pumping speed is dependent only on the addendum radius Rm as a variableAs long as->The rotor can have a greater theoretical pumping speed than conventional rotor designs. As can be seen from the following formula (9), +.>Only the function C (L) depending on the shape factor.
Step three: the function type defining the shape factor obtains a function C (L), and the trend of change of the shape factor in the direction along the axial direction includes at least one of gradually decreasing and gradually increasing, and the shape factor maximum value may be a theoretical maximum value Cmax.
Since it is determined by integrationThere are infinite numbers of functions C (L) of values, which must be obtained by defining the type of function. At this point the designer may choose one or more of the power function, exponential function, logarithmic function, trigonometric function, inverse trigonometric function curves to combine. As shown in fig. 4, the function selected for the two-leaf progressive shape factor rotor shown in fig. 1 is a linear function, i.e., a linear equation, of the power function.
In addition, the change trend of the shape factor in the axial direction at least comprises one of gradual decrease and gradual increase, wherein when the change trend of the shape factor of the rotor in the axial direction is that the shape factor is increased firstly and then is kept unchanged and then is decreased, the shape factor C trend in this case is as shown in fig. 4, with the average shape factor being smaller for the rotor segments of progressively increasing shape factor in the first segment, designated as small-shape-factor segments; a rotor section with a second section shape factor which remains unchanged and whose shape factor can reach a theoretical maximum Cmax, named a rotor with a large shape factor section; the rotor section with gradually decreasing shape coefficients in the third section is smaller in average shape coefficient and is also named as a rotor with small shape coefficient, and the rotor with large shape coefficient can reach the theoretical maximum value of the shape coefficient, so that the volume utilization coefficient and the pumping speed of the Roots pump are obviously improved, and the rotor with small shape coefficient can serve as a rib plate of the rotor with large shape coefficient to play a role in strengthening the whole rotor.
As shown in fig. 2-3, the waist of the rotor is a concave part a, and the top part B of the outer side of the rotor matched with the waist is embedded into the concave part a, and as the inlet and outlet of the Roots pump cavity are generally in the middle of the rotor, the funnel-shaped concave cavity formed by the cooperation of the waist and the top part of the rotor during rotation of the rotor is favorable for the gas on two sides of the rotor to flow towards the middle, so that the Roots rotor with gradual shape coefficient can improve the gas flow.
As shown in fig. 7 to 8, the change trend of the shape factor of the rotor along the axial direction is gradually decreasing (or gradually increasing), the relatively higher part forms a large shape factor section and the maximum shape factor can reach the theoretical maximum Cmax, and the relatively lower part forms a small shape factor section which can also act as a rib of the large shape factor section rotor, so that the whole rotor can be reinforced.
As shown in fig. 9 to 10, the change trend of the shape factor of the rotor along the axial direction is firstly decreased, then kept unchanged and then increased, the two sides of the rotor are large shape factor sections, the middle is a small shape factor section, and the function principle is the same as that of the above-mentioned form.
When the shape factor of the rotor shown in fig. 11 to 13 is also changed in the axial direction, the shape factor is changed in the number of lobes, which is different from that of the rotor shown in fig. 1 to 3, when the shape factor is changed in the axial direction after being increased.
When the function type of the shape factor is defined, the change trend of the shape factor in the axial direction needs to be ensured to at least comprise one of gradual decrease and gradual increase, so that a large shape factor section and a small shape factor section can be formed, the large shape factor section can reach the theoretical maximum value of the shape factor, the volume utilization factor and the pumping speed of the Roots pump are obviously improved, and the small shape factor section serves as a rib plate of the rotor of the large shape factor section, and plays a role in strengthening the whole rotor.
Step four: a profile equation for the rotor is determined.
After the function C (L) of the shape factor is known, since the pitch circle radius R is known, the addendum circle radius Rm of each section as shown in fig. 1 can be determined according to the formula in the related art. The molded lines are composed of different geometric line segments, the geometric form of the line segments can be one or more of circular arc lines, elliptical arc lines, cycloid lines, involute lines and straight lines, the molded line equation of the rotor has a plurality of forms, such as an arc-involute form, an arc-cycloid form, an arc-arc form and the like, and the various forms have relatively mature equations, which are well known in the art.
When the tip circle radius Rm and the pitch circle radius R are known, the rotor profile equation can be summarized from the determined profile equation form. The rotor profile equation is a precondition for drawing a profile pattern.
Step five: a three-dimensional model of the rotor is generated.
From step four, the relation between Rm and thickness L can be known. And selecting a series of Rm values, ensuring that the number of Rm values is as large as possible, summarizing a molded line equation, and drawing a graph of the molded line equation with the series of Rm values by using CAD. After the CAD graph is imported into SOLIWORKS, the molded line equation with the Rm value is moved to the corresponding axial position according to the relation between different Rm values and thickness L, and finally a lofting command of SOLIWORKS is used in the axial direction of the rotor to draw a three-dimensional model of the rotor, as shown in figures 3, 8, 10 and 12.
Fig. 5 shows the shape factor comparison of the rotor of the present invention and the conventional rotor, wherein the two-dot chain line is the shape factor of the rotor of the present invention, and is a function curve of the shape factor variation along the axis on each section in the vertical axial direction, the dotted line is the average shape factor of the rotor of the present invention, and the thick solid line is the shape factor of the conventional rotor. It can be seen that the average volume utilization of the present invention is significantly higher than that of conventional rotors.
Fig. 6 shows the volume utilization coefficient of the rotor according to the present invention compared with that of a conventional rotor, wherein the two-dot chain line is the volume utilization coefficient of the rotor according to the present invention, and is a function curve of the volume utilization coefficient on each section in the vertical axial direction along the axis, the dotted line is the average volume utilization coefficient of the rotor according to the present invention, and the thick solid line is the volume utilization coefficient of the conventional rotor. It can be seen that the average volume utilization of the present invention is significantly higher than that of conventional rotors.

Claims (2)

1. A design method of a Roots rotor with gradual change shape coefficients is characterized in that: the shape factor of the rotor gradually changes along the axial direction, the change trend is a continuous function, and the change trend at least comprises one of gradually decreasing and gradually increasing, and the method comprises the following steps:
step one: determining the relation between the theoretical pumping speed Sth' of the designed vacuum pump and the rotor thickness L, the tooth top circle radius Rm and the volume utilization coefficient lambda;
in the first step: the theoretical pumping speed Sth (L/s) of a conventional roots rotor is as follows:
in the formula (1), rm is the radius (mm) of a tooth top circle, L is the thickness (mm) of a rotor, lambda is a volume utilization coefficient, and n is the rotating speed (r/min);
the Roots rotor theoretical pumping speed Sth' (L/s) with a gradual shape factor is as follows:
in the above formula (2), sth' is the theoretical pumping speed of the rotor when the addendum circle radius Rm is a variable,the rotor average addendum circle radius (mm) in the case that addendum circle radius Rm is a variable;
as seen from the above formulas (1) and (2), the conventional roots rotor is the same as the roots rotor with a gradual change shape coefficient, and the theoretical pumping speed is related to the addendum circle radius, the rotor thickness and the volume utilization coefficient;
step two: determining an influence factor of the theoretical pumping speed under the condition that the addendum circle radius Rm is a variable, wherein the influence factor is the average addendum circle radius of the rotorAnd->The rotor achieves a greater theoretical pumping speed than conventional rotor designs,/>A shape factor dependent function C (L);
in the second step:
since the pump chamber volume and the rotor rotational speed are the same, it can be seen from the above formulas (1) and (2):
the magnitudes of the conventional rotor theoretical pumping speeds Sth and Rm are roots rotor theoretical pumping speeds Sth' with gradual shape coefficients, which depend on the magnitude of the volume utilization coefficient lambda;
the calculation formula of the volume utilization coefficient lambda is:
in the above formula (4), V Rotor For rotor volume, V Cavity body Is the volume of the pump cavity;
as can be seen from the above formula (4), V Cavity body The magnitude of the volume utilization coefficient lambda is fixed and depends only on V Rotor I.e. only on the size of the rotor form factor C;
the conventional rotor form factor is:
the rotor shape factor in the case where the tip circle radius Rm is a variable is:
the center distance R is known, if:
then:
whileFunction C (L) depending on the shape factor:
step three: defining a function type of the shape factor and obtaining a function C (L), and a trend of change of the shape factor in a direction along the axial direction includes at least one of gradually decreasing and gradually increasing;
the function C (L) is one of a power function, an exponential function, a logarithmic function, a trigonometric function and an inverse trigonometric function curve, or is a combination of a plurality of power function, exponential function, logarithmic function, trigonometric function and inverse trigonometric function curves;
the change trend of the shape factor C (L) of the rotor along the axial direction is that the rotor is gradually increased and then kept unchanged and then gradually decreased, wherein a rotor section with the shape factor gradually increased in the first section and a rotor section with the shape factor gradually decreased in the third section are rotors with small shape factors, the shape factor of the rotor section with the shape factor kept unchanged in the second section reaches the theoretical maximum Cmax, and the rotor with the shape factor is a rotor with a large shape factor, the capacity utilization factor and the pumping speed of the Roots pump are improved by the rotor with the large shape factor section, and the rotor with the small shape factor serves as a rib plate of the rotor with the large shape factor section;
step four: determining a molded line equation of the rotor;
step five: a three-dimensional model of the rotor is generated.
2. The method of designing a roots rotor with a progressive form factor of claim 1, wherein: the waist of the rotor is a concave part A, the outer side of the rotor is a top part B, and when the two rotors are matched, the top part B of one rotor is arranged in the concave part A of the other rotor.
CN202011445831.1A 2020-12-09 2020-12-09 Roots rotor with gradual change shape coefficient and design method thereof Active CN114607598B (en)

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101210557B (en) * 2006-12-31 2011-07-20 中国科学院沈阳科学仪器研制中心有限公司 Roots dry type vacuum pump rotor molded lines structure
US20080193315A1 (en) * 2007-02-08 2008-08-14 Kabushiki Kaisha Toyota Jidoshokki Roots-type fluid machine
JP2008215346A (en) * 2007-02-08 2008-09-18 Toyota Industries Corp Roots pump
US7882826B2 (en) * 2007-05-21 2011-02-08 GM Global Technology Operations LLC Tapered rotor assemblies for a supercharger
CN105422448B (en) * 2016-01-05 2017-05-31 中国石油大学(华东) A kind of screw rotor of Varied pole piece varying pitch
US10514036B2 (en) * 2017-07-25 2019-12-24 GM Global Technology Operations LLC Rotor for a positive displacement compressor

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