CN108757464A - A kind of straight pawl rotor and its Profile Design method of claw vacuum pump - Google Patents

Abstract

The invention discloses a straight claw rotor of a claw vacuum pump and a design method thereof; the rotor is composed of 11 sections of curves: 4 sections of circular arcs, 2 sections of elliptical arcs, 2 sections of envelope lines of elliptical arcs, and 1 section of cycloids The equidistant curve, the envelope of 1 segment and 1 segment; the rotor adopts the envelope of elliptical arc and elliptical arc at the claw top and claw tip to construct the shape line, and adopts the circular arc and cycloid at the claw bottom. Equidistant curves are used to construct the molding line, and the adjacent curves are connected smoothly, and there is no non-smooth connection point, which improves the mechanical properties, meshing performance and sealing performance of the straight claw rotor; the two rotors meshing with each other are completely the same and can realize The correct meshing of the profile line; the rotor has a smaller clearance volume, which improves the compression ratio of the claw vacuum pump; the top of the claw is flatter, the meshing range is large, and the meshing line is long, which further reduces wear; the rotor enriches the claw The profile type of the claw rotor and promote the development of the claw vacuum pump.

Description

A straight claw rotor of a claw vacuum pump and its profile design method

technical field

The invention relates to a claw vacuum pump, in particular to a straight claw rotor of the claw vacuum pump and a design method thereof.

Background technique

The claw vacuum pump is a dry vacuum pump widely used in petrochemical, pharmaceutical, and food fields. It has the advantages of simple structure, stable operation, and low noise; the claw rotor is the core component of the claw vacuum pump, and the claw rotor It is composed of a pair of rotors that can realize conjugate meshing. The synchronous and opposite double-rotation motion of the rotors is realized through the synchronous gears, so as to realize the periodic change of the volume of the working chamber, complete the suction, compression and discharge process of the gas, and achieve the purpose of continuous vacuuming .

The profile line and meshing performance of the claw rotor directly determine the performance of the claw vacuum pump. The common straight claw rotor profile consists of 3 arcs, 2 cycloids, 1 line and the envelope of 1 line. , the straight claw rotor is connected by a line segment at the claw arm, which improves the mechanical properties of the claw arm and reduces the stress concentration at the claw arm. The sealing performance is poor; in order to improve the performance of common straight claw rotors, a Chinese patent (patent number: ZL201610880226.4) proposes a fully smooth straight claw claw rotor. The equidistant curve of the epicycloid, the equidistant curve of a short epicycloid, the envelope of a line segment and a line segment, realize the smooth connection between all curves, there is no cusp, and improve The sealing performance, mechanical properties and meshing performance of the rotor are improved; however, when the pair of straight claw rotors mesh with each other, due to the existence of the clearance volume, the efficiency of the claw vacuum pump is reduced. Sharp point, but the range of engagement is still not flat enough and the line of engagement is shorter, which still causes some wear.

Contents of the invention

In order to further reduce the clearance volume of the straight claw rotor, reduce the compression power consumption of the vacuum pump, and at the same time reduce the wear at the top of the claw and enrich the profile types of the straight claw rotor, a straight claw vacuum pump is proposed. Claw rotor and its profile design method; the present invention uses elliptical arcs and envelopes of elliptical arcs, and equidistant curves of circular arcs and cycloids to construct straight claw rotor profile lines, realizing smooth connections between all curves, and there is no The sharp point effectively avoids areas of wear, deformation and stress concentration, and at the same time improves the sealing performance, mechanical properties and meshing performance of the rotor; an elliptical arc is used at the top of the claw to connect the arc of the top of the claw and the arc of the pitch circle, Compared with the circular arc connection, the elliptical arc connection makes the claw top flatter, and the meshing range is larger, the meshing line is longer, and the wear on the claw top is reduced; the elliptical arc and the elliptical arc envelope are used to connect the claw top arc And the claw bottom arc effectively reduces the clearance volume generated by the rotor when it is working, and improves the compression ratio of the claw vacuum pump while reducing the compression power consumption of the vacuum pump; therefore, the rotor profile improves the performance and use of the rotor. It is of great significance to enrich the types of claw rotor profiles and promote the development of claw vacuum pumps, so that the rotor can be used in higher speed, higher pressure and higher temperature applications.

In order to achieve the above object, the present invention adopts the following technical solutions:

A straight claw rotor of a claw vacuum pump, comprising: a left straight claw rotor (1) and a right straight claw rotor (2), characterized in that: the composition line of the left straight claw rotor (1) includes 11 sections of curves, according to the inverse The clockwise direction is as follows: left first elliptical arc envelope AB, left first elliptical arc BC, left claw top arc CD, left second elliptical arc DE, equidistant curve EF of left cycloid, left line segment FG, left The pitch circle arc GH, the envelope HI of the left line segment, the arc IJ of the tip of the left claw, the envelope JK of the second left elliptical arc, and the arc KA of the left claw bottom; the adjacent curves are all connected smoothly without roughness connection point; the composition line of the left straight claw rotor (1) is exactly the same as that of the right straight claw rotor (2); The forming line and the forming line of the right straight claw rotor (2) can achieve correct meshing, and the meshing relationship is: the left first elliptical arc envelope line AB in the forming line of the left straight claw rotor (1), the left The first elliptical arc BC, the left claw top circular arc CD, the left second elliptical arc DE, the equidistant curve EF of the left cycloid, the left line segment FG, the left pitch circle arc GH, the envelope line HI of the left line segment, and the tip of the left claw The circular arc IJ, the second left elliptical arc envelope JK and the left claw bottom circular arc KA are respectively combined with the right first elliptical arc bc and the right first elliptical arc envelope in the forming line of the right straight claw rotor (2) Line ab, right paw bottom arc ka, right second elliptical arc envelope jk, right paw tip arc ij, right line segment envelope hi, right pitch circle arc gh, right line segment fg, right cycloid, etc. The distance curve ef, the second right ellipse arc de and the right paw top arc cd are meshed.

A profile design method for a straight claw rotor of a claw vacuum pump, comprising the following steps:

1) Taking the origin O as the center, make the claw top circle with radius R ₁ , the pitch circle with radius R ₂ and the claw bottom circle with radius R ₃ ;

2) Make the first initial elliptical arc The equation is:

In the formula: m ₁ is the long semi-axis length of the first initial ellipse arc, n ₁ is the short semi-axis length of the first initial ellipse arc;

Make the first initial ellipse arc envelope The equation is:

In the formula:

3) Solve for the first rotation angle α, which is determined by the following equation:

first initial ellipse arc Rotate the first rotation angle α counterclockwise around the origin O to obtain the left first elliptical arc BC, the equation is:

In the formula: M _BC is the first rotation transformation matrix, as follows:

The first initial ellipse arc envelope Rotate the first rotation angle α clockwise around the origin O to obtain the left first elliptical arc envelope AB, the equation is:

In the formula: M _AB is the second rotation transformation matrix, as follows:

4) Make the second initial elliptical arc The equation is:

In the formula: m ₂ is the long semi-axis length of the second initial ellipse arc, n ₂ is the short semi-axis length of the second initial ellipse arc;

Make the second initial ellipse arc envelope The equation is:

In the formula:

5) Given the claw top arc angle β, the second initial elliptical arc Rotate α+β counterclockwise around the origin O to get the second left elliptic arc DE, the equation is:

In the formula: M _DE is the third rotation transformation matrix, as follows:

The second initial ellipse arc envelope Rotate α+β clockwise around the origin O to obtain the left second elliptical arc envelope JK, the equation is:

In the formula: M _JK is the fourth rotation transformation matrix, as follows:

6) Make the common tangent E'G of the pitch circle and the left second ellipse arc DE, and determine the second rotation angle γ according to the common tangent E'G;

7) Make the envelope of the initial line segment The equation is:

Envelope of initial line segment Rotate α+β+γ clockwise around the origin O to get the envelope HI of the left line segment, the equation is:

In the formula: M _HI is the fifth rotation transformation matrix, as follows:

8) Make the equidistant curve of the initial cycloid The equation is:

Among them, the matrix R ₄ is the radius of the arc IJ of the tip of the left claw;

9) The equidistant curve of the initial cycloid Rotate α+ζ counterclockwise around the origin O to get the equidistant curve EF of the left cycloid, the equation is:

In the formula: M _EF is the sixth rotation transformation matrix, as follows:

The third rotation angle ζ is determined by the following formula:

where the coordinates (x ₁ ,y ₁ ) are the intersection of the following two curves:

Above: t—angle parameter, rad.

The beneficial effects of the present invention are:

①The proposed straight claw rotor uses an elliptical arc at the top of the claw as the rotor profile to connect the arc of the claw top and the arc of the pitch circle, making the top of the claw more flat, with a large meshing range and a long meshing line. Can effectively reduce the wear at the top of the claw;

②The proposed straight-claw rotor uses an elliptical arc and an elliptical arc envelope to connect the claw top arc and the claw bottom arc, which effectively reduces the clearance volume formed by the two straight-claw rotors during the working process, thereby reducing the compression Power consumption, improve the compression ratio of the vacuum pump;

③The proposed straight-claw rotor realizes the smooth connection between all curves without sharp points, effectively avoids wear, deformation and stress concentration, and at the same time improves the sealing performance, mechanical properties and meshing of the vacuum pump using the straight-claw rotor performance;

④Enriched the profile type of the straight claw rotor.

Description of drawings

Figure 1 is a profile diagram of a straight claw rotor of a proposed claw vacuum pump.

Fig. 2 is a profile line generation diagram of the left rotor of the straight claw rotor of a proposed claw vacuum pump.

Fig. 3 is a meshing diagram of a straight claw rotor of a proposed claw vacuum pump.

Fig. 4 is a meshing diagram of a straight claw rotor of a proposed claw vacuum pump with a 50° offset from Fig. 3 .

Fig. 5 is a profile diagram of an existing fully smooth straight-claw rotor.

Fig. 6 is a diagram of the clearance volume of the straight claw rotor of the proposed claw vacuum pump during the working process.

Fig. 7 is a diagram of the clearance volume of a conventional fully smooth straight-claw rotor in the working process.

Fig. 8 is a diagram of the clearance volume at another position of the straight claw rotor of the proposed claw vacuum pump during operation.

Fig. 9 is a diagram of the clearance volume at another position during the working process of a conventional fully smooth straight-claw rotor.

Fig. 10 is a composition line diagram of a straight claw rotor of a proposed claw vacuum pump at the top of the claws.

Fig. 11 is a composition line diagram of a conventional all-smooth straight claw rotor at the top of the claw.

Figure 12 is a profile diagram of a common straight claw rotor.

In the figure: R ₁ is the arc radius of the claw top; R ₂ is the pitch circle radius; R ₃ is the arc radius of the claw bottom; m ₁ is the long and semi-axis length of the first initial ellipse; n ₁ is the short of the first initial ellipse arc Semi-axis length; m ₂ is the long semi-axis length of the second initial ellipse arc; n ₂ is the short semi-axis length of the second initial ellipse arc; R ₄ is the claw tip arc radius; α is the first rotation angle; β is the claw top circle Arc angle; γ is the second rotation angle; ζ is the third rotation angle; 1, 2 are the proposed straight claw rotor.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

As shown in Figure 1, it is the profile diagram of the straight claw rotor of a proposed claw vacuum pump. According to the counterclockwise direction, the rotor profiles are: the first elliptical arc envelope line AB, the first elliptical arc BC, The claw top arc CD, the second elliptical arc DE, the equidistant curve EF of the cycloid, the line segment FG, the pitch circle arc GH, the envelope line HI of the line segment, the claw tip arc IJ, the second ellipse arc envelope JK and Claw bottom arc KA; adjacent curves are smoothly connected, and there is no non-smooth connection point; the mechanical performance, meshing performance and sealing performance of the straight claw rotor are improved.

As shown in Figure 2, it is the profile line generation diagram of the left rotor of the straight claw rotor of a proposed claw vacuum pump, and the method of generating the rotor profile line is as follows:

1) Taking the origin O as the center, make the claw top circle with radius R ₁ , the pitch circle with radius R ₂ and the claw bottom circle with radius R ₃ ;

2) Make the first initial elliptical arc The equation is:

Make the first initial ellipse arc envelope The equation is:

In the formula:

3) The first initial ellipse arc Rotate the first rotation angle α counterclockwise around the origin O to obtain the left first elliptical arc BC, the equation is:

In the formula: M _BC is the first rotation transformation matrix, as follows:

The first initial ellipse arc envelope Rotate the first rotation angle α clockwise around the origin O to obtain the left first elliptical arc envelope AB, the equation is:

In the formula: M _AB is the second rotation transformation matrix, as follows:

Solve for the first rotation angle α, determined by the following equation:

4) Make the second initial elliptical arc The equation is:

Make the second initial ellipse arc envelope The equation is:

In the formula:

5) Given the claw top arc angle β, the second initial elliptical arc Rotate α+β counterclockwise around the origin O to get the second left elliptic arc DE, the equation is:

In the formula: M _DE is the third rotation transformation matrix, as follows:

The second initial ellipse arc envelope Rotate α+β clockwise around the origin O to obtain the left second elliptical arc envelope JK, the equation is:

In the formula: M _JK is the fourth rotation transformation matrix, as follows:

6) Make the common tangent E'G of the pitch circle and the left second ellipse arc DE, and determine the second rotation angle γ according to the common tangent E'G;

7) Make the envelope of the initial line segment The equation is:

Envelope of initial line segment Rotate α+β+γ clockwise around the origin O to get the envelope HI of the left line segment, the equation is:

In the formula: M _HI is the fifth rotation transformation matrix, as follows:

8) Make the equidistant curve of the initial cycloid The equation is:

Among them, the matrix R ₄ is the radius of the arc IJ of the tip of the left claw;

9) The equidistant curve of the initial cycloid Rotate α+ζ counterclockwise around the origin O to get the equidistant curve EF of the left cycloid, the equation is:

In the formula: M _EF is the sixth rotation transformation matrix, as follows:

The third rotation angle ζ is determined by the following formula:

where the coordinates (x ₁ ,y ₁ ) are the intersection of the following two curves:

Above: t—angle parameter, rad.

As shown in Figure 3 and Figure 4, it is the meshing diagram of the straight claw rotor of a proposed claw vacuum pump in operation; In Fig. 4, the left straight claw rotor (1) rotates 50° clockwise, and the right straight claw rotor (2) rotates 50° counterclockwise; in Fig. 3, the left first elliptical arc in the left straight claw rotor (1) wraps The winding line AB, the arc KA at the bottom of the left claw, the envelope JK of the second left elliptical arc, and the arc IJ of the tip of the left claw are respectively connected with the first right elliptical arc bc and the top arc of the right claw in the right straight claw rotor (2). cd, the second right elliptical arc de meshes with the equidistant curve ef of the right cycloid. In Fig. 4, the left first elliptical arc BC, the left claw top arc CD, the left first The equidistant curve EF of the two elliptical arcs DE and the left cycloid is respectively related to the right first elliptical arc envelope ab, the right claw bottom arc ka, and the right second elliptical arc envelope jk in the right straight claw rotor (2) It meshes with the arc ij of the right claw tip; except as shown in the figure, the remaining curve of the left straight claw rotor (1) meshes with the remaining curve of the right straight claw rotor (2).

As shown in Figure 5, a fully smooth straight-claw rotor has 11 curves in its profile, which are in the counterclockwise direction: pitch circle arc GH, line segment envelope HI, third claw tip arc IJ, cycloid equidistant curve JK, claw bottom arc KA, cycloid equidistant curve AB, first claw tip arc BC, claw top arc CD, second claw tip arc DE, cycloid equidistant curve Between EF and line segment FG, a smooth connection is realized between adjacent curves, and there is no non-smooth connection point.

As shown in Figure 6 and Figure 7, it is the clearance volume formed by the straight claw rotor of the proposed claw vacuum pump during the working process and the clearance formed by a fully smooth straight claw claw rotor during the working process The suction and exhaust openings of the two are consistent, the arc angles of the top of the claws are equal, and the length of the semi-minor axis of each ellipse arc is equal to the radius of the arc of each claw tip; the existence of the clearance volume will cause a part of the exhaust cavity to be blocked. The compressed gas cannot be removed and remains in the clearance volume, which leads to waste of compression power consumption and reduces the working efficiency of the claw vacuum pump; due to the surplus of the straight claw rotor of the claw vacuum pump proposed in Fig. 6 The clearance volume is smaller than that of a fully smooth straight-claw rotor in Fig. 7, so the proposed straight-claw rotor has smaller compression power consumption, higher work efficiency and better Great compression ratio.

As shown in Fig. 8 and Fig. 9, it is the clearance volume of another position of the straight claw rotor of the proposed claw vacuum pump in the working process and the clearance volume of a fully smooth straight claw claw rotor in the working process For the clearance volume at another position, the suction and exhaust openings of the two are consistent, the arc angles of the top of the claws are equal, and the length of the semi-minor axis of each ellipse arc is equal to the radius of the arc of each claw tip; The clearance volume of the straight claw rotor of this kind of claw vacuum pump at the position in the figure is smaller than that of a fully smooth straight claw rotor in the figure in Figure 9, so the proposed straight claw The rotor has smaller compression power consumption, higher work efficiency and larger compression ratio.

As shown in Fig. 10 and Fig. 11, the composition line of the straight claw rotor at the top of the claw of the proposed claw vacuum pump and the composition line of a fully smooth claw rotor at the top of the claw are respectively; It can be seen from the figure that, when the arc angles of the claw tops are the same, and the length of the minor semi-axis of each elliptical arc is equal to the radius of each claw tip arc, compared with the fully smooth straight claw claw rotor, the circular arc is used as the sharp point at the claw top. The modified profile of the proposed straight claw rotor adopts the elliptical arc as the modified profile of the sharp point at the claw top, so that the claw top is flatter, the range of the meshing profile is large, and the meshing line is longer, which effectively reduces the Reduced wear at the top of the claws.

As shown in Figure 12, the common straight-claw rotor profile is composed of 3 arcs, 2 cycloids, 1 line segment and the envelope of 1 line segment, in the counterclockwise order: cycloid AB, claw top Arc BC, cycloid CD, pitch circle arc DE, envelope EF of line segment, cycloid FG and claw-bottom arc GA; among them, connection points B, C and F are not smooth connection points, that is, sharp point; the existence of sharp points will easily lead to wear, deformation, stress concentration and leakage in this area; since the straight claw rotor of the proposed claw vacuum pump adopts elliptical arc correction at point B and point C, and adopts elliptical arc correction at point F The arc correction is realized, and all curves are connected smoothly, so that the meshing between the middle point and the curve of the common straight claw rotor becomes the meshing between the curves, effectively avoiding the occurrence of wear, deformation and stress concentration at the sharp point, and Reduced leakage.

Although the specific implementation of the present invention has been described above in conjunction with the accompanying drawings, it does not limit the protection scope of the present invention. Those skilled in the art should understand that on the basis of the technical solution of the present invention, those skilled in the art do not need to pay creative work Various modifications or variations that can be made are still within the protection scope of the present invention.

Claims (2)

1. A straight claw rotor of a claw vacuum pump, comprising: a left straight claw rotor (1) and a right straight claw rotor (2), characterized in that: the composition line of the left straight claw rotor (1) includes 11 sections of curves, According to the counterclockwise direction: the first left elliptical arc envelope line AB, the left first elliptical arc BC, the left claw top arc CD, the left second elliptical arc DE, the equidistant curve EF of the left cycloid, and the left line segment FG , the left pitch circle arc GH, the envelope HI of the left line segment, the left claw tip arc IJ, the left second elliptical arc envelope JK, and the left claw bottom arc KA; the adjacent curves are all smoothly connected, and there is no Unsmooth connection points; the composition line of the left straight claw rotor (1) is exactly the same as that of the right straight claw rotor (2); ) and the right straight-claw rotor (2) can achieve correct meshing, and the meshing relationship is: the left first elliptical arc envelope AB in the left straight-claw rotor (1) , the left first elliptical arc BC, the left claw top arc CD, the left second elliptical arc DE, the equidistant curve EF of the left cycloid, the left line segment FG, the left pitch circle arc GH, the envelope line HI of the left line segment, The left claw tip arc IJ, the left second elliptical arc envelope JK and the left claw bottom arc KA are respectively combined with the right first elliptical arc bc and the right first elliptical arc in the forming line of the right straight claw rotor (2) Envelope ab, right claw bottom arc ka, right second elliptical arc envelope jk, right claw tip arc ij, envelope hi of right line segment, right pitch circle arc gh, right line segment fg, right cycloid The equidistant curve ef, the right second ellipse arc de and the right claw top arc cd are meshed. 2. A profile design method for a straight claw rotor of a claw vacuum pump as claimed in claim 1, characterized in that: comprising the following steps: 1) Taking the origin O as the center, make the claw top circle with radius R ₁ , the pitch circle with radius R ₂ and the claw bottom circle with radius R ₃ ; 2) Make the first initial elliptical arc The equation is: In the formula: m ₁ is the long semi-axis length of the first initial ellipse arc, n ₁ is the short semi-axis length of the first initial ellipse arc; Make the first initial ellipse arc envelope The equation is: In the formula: 3) The first initial ellipse arc Rotate the first rotation angle α counterclockwise around the origin O to obtain the left first elliptical arc BC, the equation is: In the formula: M _BC is the first rotation transformation matrix, as follows: The first initial ellipse arc envelope Rotate the first rotation angle α clockwise around the origin O to obtain the left first elliptical arc envelope AB, the equation is: In the formula: M _AB is the second rotation transformation matrix, as follows: Solve for the first rotation angle α, determined by the following equation: 4) Make the second initial elliptical arc The equation is: In the formula: m ₂ is the long semi-axis length of the second initial ellipse arc, n ₂ is the short semi-axis length of the second initial ellipse arc; Make the second initial ellipse arc envelope The equation is: In the formula: 5) Given the claw top arc angle β, the second initial elliptical arc Rotate α+β counterclockwise around the origin O to get the second left elliptic arc DE, the equation is: In the formula: M _DE is the third rotation transformation matrix, as follows: The second initial ellipse arc envelope Rotate α+β clockwise around the origin O to obtain the left second elliptical arc envelope JK, the equation is: In the formula: M _JK is the fourth rotation transformation matrix, as follows: 6) Make the common tangent E'G of the pitch circle and the left second ellipse arc DE, and determine the second rotation angle γ according to the common tangent E'G; 7) Make the envelope of the initial line segment The equation is: Envelope of initial line segment Rotate α+β+γ clockwise around the origin O to get the envelope HI of the left line segment, the equation is: In the formula: M _HI is the fifth rotation transformation matrix, as follows: 8) Make the equidistant curve of the initial cycloid The equation is: Among them, the matrix R ₄ is the radius of the arc IJ of the tip of the left claw; 9) The equidistant curve of the initial cycloid Rotate α+ζ counterclockwise around the origin O to get the equidistant curve EF of the left cycloid, the equation is: In the formula: M _EF is the sixth rotation transformation matrix, as follows: The third rotation angle ζ is determined by the following formula: where the coordinates (x ₁ ,y ₁ ) are the intersection of the following two curves: Above: t—angle parameter, rad.