CN206478000U

CN206478000U - A kind of varying pitch conical screw rotor of self-balancing

Info

Publication number: CN206478000U
Application number: CN201621334793.1U
Authority: CN
Inventors: 崔锋; 刘强; 王君; 崔冬; 魏蜀红
Original assignee: China University of Petroleum East China
Current assignee: China University of Petroleum East China
Priority date: 2016-12-07
Filing date: 2016-12-07
Publication date: 2017-09-08
Anticipated expiration: 2026-12-07

Abstract

The utility model discloses a kind of varying pitch conical screw rotor of self-balancing, screw rotor is integrally conical, from suction end (I I) to exhaust end (VII VII), rotor outside circle arc radius R₁With helical pitch (P₁、P₂、P₃) be gradually reduced, fillet radius R₃, addendum thickness (S₁、S₂、S₃) and thickness at root of tooth (T₁、T₂、T₃) gradually increase；In any axial positions, section molded line is change, but the type of the constituent curve of section molded line is identical, and all including 12 curves, connection is completely smooth between adjacent curve；A kind of varying pitch conical screw rotor of the self-balancing proposed can be effectively increased suction end working chamber volume, reduce exhaust end working chamber volume, rotor is had larger internal volume ratio, and improve the interstage seal performance of exhaust end and the intensity of rotor；In any axial positions of screw rotor, the centre of form of section molded line is all on the centre of gyration line of screw rotor, and the dynamic balance performance of screw rotor is good.

Description

A kind of varying pitch conical screw rotor of self-balancing

Technical field

The present invention relates to Twin-screw vacuum pump, more particularly to suitable for Twin-screw vacuum pump a kind of self-balancing varying pitch Conical screw rotor.

Background technology

Twin-screw vacuum pump is a kind of positive-displacement vacuum pump, and because of its pumping chamber dry type oil-free, operate steadily reliable advantage, It is widely used in petrochemical industry, food pharmaceutical, vacuum heat, nanometer manufacture, defense technology field；The core of Twin-screw vacuum pump Heart parts are under synchronous incorgruous dual AC power motion, intermeshing two screw rotors；Screw rotor and its section type The performance of line, directly affects interstage seal performance, mechanical property and the final vacuum of screw vacuum pump.

Single head conical screw rotor disclosed in patent CN101351646, suction end external diameter is big, and exhaust end external diameter is small, work When working chamber volume be gradually reduced, there is interior compression process；The transverse tooth thickness changing rule of the screw rotor is：Close to the tooth of suction end Top thickness degree is larger, occupies a part of aspirated volume, influences rate of air sucked in required, higher close to exhaust end gas pressure, but addendum thickness It is smaller, it is impossible to effectively to stop leakage between the level that gases at high pressure pass through crest top land；While the screw rotor, its axial cross section centre of form is not On the centre of gyration line of screw rotor, the normal engagement of eccentric force influence is also easy to produce.

The content of the invention

There is eccentric force, section molded line in order to solve the screw rotor in above-mentioned document to there is cusp, suction end tooth top thick The problem of leaking larger between the larger occupancy aspirated volume of degree, the smaller level for passing the gas through crest top land of exhaust end addendum thickness, be The species of abundant screw rotor, the present invention proposes a kind of varying pitch conical screw rotor of self-balancing；Screw rotor is tapered, From suction end (I-I) to exhaust end (VII-VII), the helical pitch (P of screw rotor₁、P₂、P₃) be gradually reduced, addendum thickness (S₁、S₂、 S₃) and thickness at root of tooth (T₁、T₂、T₃) gradually increase, the air-breathing that thus can further increase screw rotor in suction end (I-I) is held Product, effective stop screw rod rotor is let out between exhaust end (VII-VII) two, place operated adjacent chamber between the level that gas passes through crest top land Leakage, while increasing intensity of the screw rotor at exhaust end (VII-VII) place, Reducing distortion；The section type that screw rotor is used Line is completely smooth and can realize correct engagement, eliminates the harmful effect of rough tie point, improves screw rotor Force-bearing situation；The screw rotor proposed is S-shaped in any axial positions, its section molded line, and the centre of form of section molded line is all On the centre of gyration line of screw rotor, make screw rotor that there is good dynamic balance performance；The screw rotor proposed, can Increase suction end working chamber volume, reduce the interior volume specific ratio in the working chamber volume of exhaust end, the increase course of work, improve double The pumping speed and final vacuum of screw vacuum pump.

To achieve these goals, the present invention is adopted the following technical scheme that：

A kind of varying pitch conical screw rotor of self-balancing proposed by the present invention, from suction end (I-I) to exhaust end (VII- VII), screw rotor is tapered, and screw rotor is complete smooth, in the absence of rough place；From suction end (I-I) to exhaust end (VII-VII), the helical pitch (P of screw rotor₁、P₂、P₃) be gradually reduced, addendum thickness (S₁、S₂、S₃) and thickness at root of tooth (T₁、T₂、T₃) Gradually increase；Any axial positions screw rotor section molded line be S-shaped, and section molded line the centre of form in screw rotor Centre of gyration line on.

A kind of varying pitch conical screw rotor of self-balancing, in any axial positions, the section molded line of screw rotor is all Differ, be change, but on the molded line of section each section of constituent curve type it is identical with quantity, totally 12 sections of curves, including：First Addendum circle arc AB, the first tip circular-arc BC, the equidistant curve CD of the first cycloid, the first tooth root circular arc DE, first connect circular arc Envelope EF, the first connection circular arc FG, the second addendum circle arc GH, the second tip circular-arc HI, the equidistant curve IJ of the second cycloid, the Two tooth root circular arc JK, the envelope KL of the second connection circular arc, the second connection circular arc LA；All it is complete light between adjacent two sections of curves Slip, rough tie point is not present on the molded line of section；The first addendum circle arc AB, the first tip circular-arc on the molded line of section BC, the equidistant curve CD of the first cycloid, the second tooth root circular arc JK, the envelope KL of the second connection circular arc, the second connection circular arc LA, Respectively with the second addendum circle arc GH, the second tip circular-arc HI, the equidistant curve IJ of the second cycloid, the first tooth root circular arc DE, first The envelope EF of circular arc, the first connection circular arc FG are centrosymmetric on centre of gyration point O.

A kind of varying pitch conical screw rotor of self-balancing, in the course of the work, left-hand screw rotor (301) and dextrorotation spiral shell Bar rotor (302) can realize right-on engagement in synchronous incorgruous dual AC power motion；It is left in any axial positions The left-handed section molded line (201) of rotation screw rotor (301) and the dextrorotation section molded line (202) of right-hand screw rotor (302) are completely Identical, simply phase is different；The first addendum circle arc AB on the left-handed section molded line (201) of left-hand screw rotor (301), first Tip circular-arc BC, the equidistant curve CD of the first cycloid, the second tooth root circular arc JK, the envelope KL of the second connection circular arc, second connect Circular arc LA is met, respectively with the second tooth root circular arc jk on the dextrorotation section molded line (202) of right-hand screw rotor (302), the second pendulum The equidistant curve ij of line, the second tip circular-arc hi, the second addendum circle arc gh, the second connection circular arc fg, the bag of the second connection circular arc Winding thread ef can realize correct engagement.

A kind of varying pitch conical screw rotor of self-balancing, left-hand screw rotor (301) by left-handed section molded line (201) from Suction end (I-I) deploys to exhaust end (VII-VII) along left-handed Method of Variable Pitch Screw, and right-hand screw rotor (302) is by dextrorotation section Molded line (202) deploys from suction end (I-I) to exhaust end (VII-VII) along dextrorotation Method of Variable Pitch Screw, with the revolution of screw rotor The intersection point of plane is the origin of coordinates where center line and suction end, using centre of gyration line as z-axis, sets up three-dimensional coordinate system, Helix equation is：

Left-handed Method of Variable Pitch Screw：

Dextrorotation Method of Variable Pitch Screw：

In formula：τ-spiral angle of spread, rad；R-helix base radius, mm；N-screw rod helical pitch number；k₁、k₂- become spiral shell It is relevant with specific pitch changing rule away from parameter；X (τ), y (τ), z (τ)-Method of Variable Pitch Screw are in three reference axis Projection；

While the section molded line of screw rotor deploys along helix, in any axial positions, section of screw rotor The addendum circle arc radius R of face molded line₁, fillet radius R₃, addendum circle arc central angle alpha also with spiral angle of spread τ change Change, its rule is：

Addendum circle arc radius：

Fillet radius：

The central angle of addendum circle arc：

In formula：R_s1、R_d1- respectively in the addendum circle arc radius at suction end (I-I) and exhaust end (VII-VII) place；R_s3、 R_d3- respectively in the fillet radius at suction end (I-I) and exhaust end (VII-VII) place；α_s、α_d- it is respectively in suction end The central angle of the addendum circle arc at (I-I) and exhaust end (VII-VII) place；Z (τ)-coordinate value；

On a kind of varying pitch conical screw rotor of self-balancing, the left-handed section molded line (201) of left-hand screw rotor (301) Each composition curvilinear equation it is as follows：

1. the first addendum circle arc AB equation is：

2. the first tip circular-arc BC equation is：

In formula：R-tip circular-arc radius；(x_M,y_MThe centre point M of)-tip circular-arc coordinate；

Determine the centre point M (x of tip circular-arc_M,y_M) coordinate, the following two equations of simultaneous first obtain intersection point：

By intersection point determined by above-mentioned two equation, turned clockwise β angles around revolution central point O, the crown center of circle can be obtained Point M (x_M,y_M)；Wherein

3. the equidistant curve CD of the first cycloid determination mode is：

First one section of curve is determined by following equations：

By curve determined by above-mentioned equation, turned clockwise β angles around revolution central point O, can obtain the first cycloid etc. Away from curve CD；

4. the second tooth root circular arc JK equations are：

5. the envelope KL of the second connection circular arc determination mode is：

First one section of curve is determined by following equations：

By initial curve determined by above-mentioned equation, turned clockwise α angles around revolution central point O, the second connection can be obtained The envelope KL, α of circular arc are the central angle of addendum circle arc；

6. the second connection circular arc LA equation is：

In formula：L_p- the second connection circular arc LA centre point N is determined apart from centre of gyration point O length by below equation：

Beneficial effects of the present invention are：

1. a kind of varying pitch conical screw rotor of the self-balancing proposed, screw rotor is tapered, tooth on the molded line of section Tip circle arc radius R₁It is gradually reduced, fillet radius R₃Gradually increase, from the suction end (I-I) of screw rotor to exhaust end (VII-VII), the helical pitch (P of screw rotor₁、P₂、P₃) be gradually reduced, it can fully increase the working chamber volume of suction end, reduce exhaust The working chamber volume at end, makes rotor have larger internal volume ratio, improves the pumping speed of Twin-screw vacuum pump；

2. from the suction end (I-I) of screw rotor to exhaust end (VII-VII), addendum thickness (S₁、S₂、S₃) and thickness at root of tooth (T₁、T₂、T₃) gradually increase, it can further increase suction end working chamber volume, effectively stop and pass through close to gas at exhaust end Leaked between the level of crest top land, and ensure the intensity of screw rotor exhaust end, reduce deformation during work；

3. the section molded line of screw rotor, the equidistant curve and addendum circle arc of cycloid, spiral shell are connected using one section of tip circular-arc Bar rotor is complete smooth and can realize correct engagement, while eliminating the region of stress concentration of rough tie point, improves spiral shell The force-bearing situation of bar rotor, and the leakage aggravation for preventing cusp abrasion from causing；

4. in any axial positions, the section molded line of screw rotor is S-shaped, and the centre of form of section molded line is in screw rotor On centre of gyration line, i.e., screw rotor has good dynamic balance performance.

Brief description of the drawings

Fig. 1 is the section molded lines of the varying pitch conical screw rotor of self-balancing.

Fig. 2 is the engagement figure of the section molded line of two screw rotors.

Fig. 3 is the varying pitch conical screw rotor figure of self-balancing.

The engagement figure of the varying pitch conical screw rotor of two self-balancings when Fig. 4 is work.

Fig. 5 is the section molded line engagement figure in any two screw rotors of axial positions.

In figure：R₁、R₂、R₃- it is respectively addendum circle arc radius, pitch radius, fillet radius, three on the molded line of section Length relation be：2R₂=R₁+R₃；The central angle of α-addendum circle arc；Phases of the centre point M relative to x-axis of β-tip circular-arc Parallactic angle；S₁、S₂、S₃The addendum thickness of-screw rotor；T₁、T₂、T₃The thickness at root of tooth of-screw rotor；P₁、P₂、P₃- screw rod turns The helical pitch of son；301-left-hand screw rotor；302-right-hand screw rotor；The left-handed section molded line of 201-left-hand screw rotor； The dextrorotation section molded line of 202-right-hand screw rotor；The centre of gyration of point O, o-respectively two screw rotor section molded line Point, the axis at place is respectively the centre of gyration line of two screw rotors.

Embodiment

The invention will be further described with embodiment below in conjunction with the accompanying drawings.

As shown in figure 1, the section molded lines of the varying pitch conical screw rotor for self-balancing；The section molded line of screw rotor Refer to：With a plane perpendicular to screw rotor centre of gyration line, screw rotor, section part are blocked from any axial positions Obtained contour curve；The section molded line of screw rotor is surrounded by 12 sections of curves, is followed successively by clockwise：First addendum circle arc AB, the first tip circular-arc BC, the equidistant curve CD of the first cycloid, the first tooth root circular arc DE, the envelope EF of the first circular arc, first Connect circular arc FG, the second addendum circle arc GH, the second tip circular-arc HI, the equidistant curve IJ of the second cycloid, the second tooth root circular arc JK, The envelope KL of second connection circular arc, the second connection circular arc LA；It is smoothly connected between adjacent curve, the section of whole screw rotor Rough tie point is not present on molded line；Whole cross section molded line is the first addendum circle arc on S-shaped and Central Symmetry, section molded line AB, the first tip circular-arc BC, the equidistant curve CD of the first cycloid, the second tooth root circular arc JK, second connection circular arc envelope KL, Second connection circular arc LA, respectively with the second addendum circle arc GH, the second tip circular-arc HI, the equidistant curve IJ of the second cycloid, first Tooth root circular arc DE, the envelope EF of the first circular arc, the first connection circular arc FG are centrosymmetric on centre of gyration point O.

As shown in Fig. 2 the engagement figure of the section molded line for two screw rotors；In same axial positions, two screw rods The section molded line of rotor is identical, and simply phase is different；The first addendum circle arc AB in left-handed section molded line (201), first Tip circular-arc BC, the equidistant curve CD of the first cycloid, the first tooth root circular arc DE, the envelope EF of the first circular arc, the first connection circle Arc FG, respectively with the second tooth root circular arc jk, the equidistant curve ij of the second cycloid, the second crown in dextrorotation section molded line (202) Circular arc hi, the second addendum circle arc gh, the second connection circular arc fg, the envelope ef of the second connection circular arc can be realized and correctly nibbled Close.

As shown in figure 3, being the varying pitch conical screw rotor figure of self-balancing；I-I and VII-VII represents that screw rod turns respectively in figure The corresponding axial location of sub- suction end and exhaust end；Left-hand screw rotor (301) is by left-handed section molded line (201) from suction end (I-I) deploys to exhaust end (VII-VII) along left-handed Method of Variable Pitch Screw, and right-hand screw rotor (302) is by dextrorotation section molded line (202) deploy from suction end (I-I) to exhaust end (VII-VII) along dextrorotation Method of Variable Pitch Screw；Because the spiral shell of Method of Variable Pitch Screw Away from being gradually reduced from suction end (I-I) to exhaust end (VII-VII), so the helical pitch (P of the screw rotor of generation₁、P₂、P₃) also by It is decrescence small, i.e. P₁>P₂>P₃；In section molded line along helix deploy while, the addendum circle arc radius R on the molded line of section₁Gradually Reduce, fillet radius R₃Gradually increase, make the global shape of screw rotor tapered；Left-handed and dextrorotation the regulation of helix For：With left hand thumb, dynamic point is as left-handed along remaining four sensings rising referred on suction end sensing exhaust extreme direction, helix； Dynamic point on exhaust extreme direction, helix is pointed to by suction end with hand thumb and rises as dextrorotation along remaining four sensing referred to.

As shown in figure 4, during for work the varying pitch conical screw rotor of two self-balancings engagement figure；From suction end (I- I) exhaust end (VII-VII), the addendum thickness (S of screw rotor are arrived₁、S₂、S₃) and thickness at root of tooth (T₁、T₂、T₃) gradually increase, i.e. S₁ <S₂<S₃、T₁<T₂<T₃；During section molded line is along helix expansion generation screw rotor, spiral angle of spread τ value takes 0,π,2 π,During 3 π, corresponding axial location respectively with I-I, II-II, III-III, IV-IV, V-V, VI-VI, VII-VII represents.

As shown in figure 5, in the section molded line engagement figure of any two screw rotors of axial positions；Fig. 5 (a), (b), (c), (d), (e), (f), (g) are corresponded in axial location I-I, II-II, III-III, IV-IV, V-V, VI-VI, VII-VII respectively Place, the instantaneous engagement figure of two screw rotor section molded line；It can be seen that the profile in any two screw rods of axial positions is At a fully engaged, it can be said that bright two screw rotors are intermeshing on the whole；At axially different position, section type The Major Variation of line is：From suction end (I-I) to exhaust end (VII-VII), the addendum circle arc half of rotor axial section molded line Footpath R₁It is gradually reduced, fillet radius R₃Gradually increase, the central angle alpha of addendum circle arc gradually increases；Thus two phases generated Mutual at a fully engaged screw rotor, by suction end (I-I) to exhaust end (VII-VII), working chamber volume is gradually reduced, and turns screw rod There is interior compression process in son.

Although above-mentioned the embodiment of the present invention is described with reference to accompanying drawing, not to present invention protection model The limitation enclosed, one of ordinary skill in the art should be understood that on the basis of technical scheme those skilled in the art are not Need to pay various modifications or deform still within protection scope of the present invention that creative work can make.

Claims

1. a kind of varying pitch conical screw rotor of self-balancing, it is characterized in that：Screw rotor is tapered, from suction end (I-I) to Exhaust end (VII-VII), the addendum circle arc radius R of screw rotor₁With helical pitch (P₁、P₂、P₃) be gradually reduced, fillet radius R₃、 Addendum thickness (S₁、S₂、S₃) and thickness at root of tooth (T₁、T₂、T₃) gradually increase；Screw rotor is complete smooth, in the absence of rough Place；In any axial positions, the section molded line of screw rotor is S-shaped, and the centre of form all returning in screw rotor of section molded line Turn on center line.

2. a kind of varying pitch conical screw rotor of self-balancing as claimed in claim 1, it is characterized in that：In any axial location Place, the section molded line of screw rotor is different from, and is change, but on the molded line of section each section of constituent curve type and quantity phase Together, totally 12 sections of curves, including：First addendum circle arc AB, the first tip circular-arc BC, the equidistant curve CD of the first cycloid, the first tooth Root circular arc DE, the envelope EF of the first connection circular arc, the first connection circular arc FG, the second addendum circle arc GH, the second tip circular-arc HI, The equidistant curve IJ of second cycloid, the second tooth root circular arc JK, the envelope KL of the second connection circular arc, the second connection circular arc LA；Phase All it is completely smooth on connection, section molded line between adjacent two sections of curves and rough tie point is not present；On the molded line of section One addendum circle arc AB, the first tip circular-arc BC, the equidistant curve CD of the first cycloid, the second tooth root circular arc JK, the second connection circular arc Envelope KL, second connection circular arc LA, respectively with the second addendum circle arc GH, the second tip circular-arc HI, the second cycloid it is equidistant Curve IJ, the first tooth root circular arc DE, the envelope EF of the first circular arc, the first connection circular arc FG are in center on centre of gyration point O Symmetrically.

3. a kind of varying pitch conical screw rotor of self-balancing as claimed in claim 1, it is characterized in that：In the course of the work, Left-hand screw rotor (301) and right-hand screw rotor (302) can be realized right-on in synchronous incorgruous dual AC power motion Engagement；In any axial positions, the left-handed section molded line (201) of left-hand screw rotor (301) and right-hand screw rotor (302) Dextrorotation section molded line (202) it is identical, simply phase is different；The left-handed section molded line (201) of left-hand screw rotor (301) On the first addendum circle arc AB, the first tip circular-arc BC, the equidistant curve CD of the first cycloid, the second tooth root circular arc JK, second connect Connect circular arc envelope KL, second connection circular arc LA, respectively with the dextrorotation section molded line (202) of right-hand screw rotor (302) The second tooth root circular arc jk, the equidistant curve ij of the second cycloid, the second tip circular-arc hi, the second addendum circle arc gh, second connection Circular arc fg, the envelope ef of the second connection circular arc can realize correct engagement.

4. a kind of varying pitch conical screw rotor of self-balancing as claimed in claim 1, it is characterized in that：Left-hand screw rotor (301) deployed by left-handed section molded line (201) from suction end (I-I) to exhaust end (VII-VII) along left-handed Method of Variable Pitch Screw, it is right Screw rotor (302) is revolved by dextrorotation section molded line (202) from suction end (I-I) to exhaust end (VII-VII) along dextrorotation varying pitch spiral shell Spin line is deployed；Intersection point using plane where the centre of gyration line of screw rotor and suction end is the origin of coordinates, with centre of gyration line For z-axis, three-dimensional coordinate system is set up, helix equation is：

Left-handed Method of Variable Pitch Screw：

Dextrorotation Method of Variable Pitch Screw：

In formula：τ-spiral angle of spread, rad；R-helix base radius, mm；N-screw rod helical pitch number；k₁、k₂- varying pitch is joined Number, it is relevant with specific pitch changing rule；X (τ), y (τ), z (τ)-coordinate value；

While the section molded line of screw rotor deploys along helix, in any axial positions, the section type of screw rotor The addendum circle arc radius R of line₁, fillet radius R₃, addendum circle arc central angle alpha also become with spiral angle of spread τ change Change, its rule is：

Addendum circle arc radius：

Fillet radius：

The central angle of addendum circle arc：

In formula：R_s1、R_d1- respectively in the addendum circle arc radius at suction end (I-I) and exhaust end (VII-VII) place；R_s3、R_d3- point Not Wei suction end (I-I) and exhaust end (VII-VII) place fillet radius；α_s、α_d- be respectively in suction end (I-I) and The central angle of the addendum circle arc at exhaust end (VII-VII) place；Z (τ)-coordinate value of the Method of Variable Pitch Screw in z-axis.

5. a kind of varying pitch conical screw rotor of self-balancing as claimed in claim 1, it is characterized in that：In any axial location Place, the determination mode of the left-handed upper each section of curve of section molded line (201) of left-hand screw rotor (301) is as follows：

1. the first addendum circle arc AB equation is：

2. the first tip circular-arc BC equation is：

By intersection point determined by above-mentioned equation, turned clockwise β angles around revolution central point O, crown centre point M (x can be obtained_M, y_M)；Wherein

3. the equidistant curve CD of the first cycloid determination mode is：

First one section of curve is determined by following equations：

By curve determined by above-mentioned equation, turned clockwise β angles around revolution central point O, the equidistant song of the first cycloid can be obtained Line CD；

4. the second tooth root circular arc JK equations are：

First one section of curve is determined by following equations：

By initial curve determined by above-mentioned equation, turned clockwise α angles around revolution central point O, the second connection circular arc can be obtained Envelope KL, α is the central angle of addendum circle arc；

6. the second connection circular arc LA equation is：

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6. a kind of Twin-screw vacuum pump, it is characterized in that：Turned using the varying pitch conical screw of self-balancing as claimed in claim 1 Son.

7. a kind of double-screw compressor, it is characterized in that：Turned using the varying pitch conical screw of self-balancing as claimed in claim 1 Son.

8. a kind of twin-screw expander, it is characterized in that：Turned using the varying pitch conical screw of self-balancing as claimed in claim 1 Son.