A high-efficiency three-claw vacuum pump

Abstract

The invention discloses a high-efficiency three-claw vacuum pump. The claw rotor profile is simple and consists of only four curves, which solves the problem of large limitations in the selection of design parameters of the three-claw rotor; the traditional claw top and claw bottom arcs are omitted, and the eccentric involute and its envelope are introduced, which significantly improves the volumetric efficiency of the three-claw vacuum pump; the elliptical arc is used at the claw tip to improve the leakage at the claw tip and reduce the wear of the claw tip, which is of great significance to the performance optimization of the claw vacuum pump. At the same time, an axial exhaust port is designed in combination with the rotor profile, so that the gas in the cavity can be completely discharged, avoiding excessive compression of the gas, and effectively reducing the energy consumption of the claw vacuum pump.

Description

Technical Field

[0001] The invention relates to the field of vacuum acquisition equipment, in particular to a high-efficiency three-claw vacuum pump. Background Art

[0002] The claw vacuum pump achieves the process of gas suction, compression and discharge by the synchronous counter-rotating double-rotational motion of a pair of meshing claw rotors, which causes the volume of the working chamber to change periodically. It has the advantages of simple structure, smooth operation, low noise and dry oil-free, and is widely used in the electronics and petrochemical industries.

[0003] As the core component of claw fluid machinery, the design of the claw rotor's profile directly affects the performance of the claw fluid machinery, such as sealing, area utilization, work efficiency and service life. Patent CN100526608C proposes a linear arc three-claw rotor and its design method, the left rotor of which is composed of a cycloid, an eccentric arc and a line segment, and the right rotor is composed of a cycloid, an arc envelope and a linear envelope. This design has many constraints and the rotor design process is complicated. Patent CN108343605A proposes a three-claw vacuum pump, the claw top arc and the claw bottom arc of the left claw rotor of the three-claw vacuum pump are smoothly connected by a sine line, and the claw top arc and the claw bottom arc of the right claw rotor are smoothly connected by a sine envelope, which expands the range of design parameters. However, the volumetric efficiency of the three-claw vacuum pump is low, the profile composition is complex, and there is a sharp point at the claw tip. During the operation of the claw vacuum pump, there is leakage at the claw tip and the claw tip is severely worn. Summary of the invention

[0004] In order to solve the problems existing in the above-mentioned three-claw vacuum pump and to enrich the profile types of claw rotors, the present invention introduces eccentric involutes and their envelopes into the design of three-claw rotors, omitting traditional claw top and claw bottom arcs, combining elliptical arcs and elliptical arc envelopes to construct an eccentric involute type fully smooth three-claw rotor, and designs a corresponding exhaust port, which significantly improves the volumetric efficiency of the three-claw vacuum pump, improves leakage at the claw tip, and reduces the wear of the claw tip, which is of great significance to the performance optimization of the claw vacuum pump.

[0005] In order to achieve the above object, the present invention adopts the following technical solution:

[0006] The high-efficiency three-claw vacuum pump comprises: a left-claw rotor, a right-claw rotor, a cavity and an exhaust end cover; the characteristics are: the left profile of the left-claw rotor is 120° centrally symmetrical about its rotation center O1, that is, after the left-claw rotor rotates 120° counterclockwise or clockwise around its rotation center O1, it completely overlaps with itself; one-third of the left profile of the left-claw rotor is composed of three curves, which are: eccentric involute envelope AB, left claw tip elliptical arc BC, left elliptical arc envelope CD in the clockwise direction;

[0007] The right profile of the right claw rotor is 120° centrally symmetrical about its rotation center O2, that is, after the right claw rotor rotates 120° counterclockwise or clockwise around its rotation center O2, it completely coincides with itself; one third of the right profile of the right claw rotor is composed of three curves, which are: eccentric involute ab, right elliptical arc envelope bc, and right claw tip elliptical arc cd in the counterclockwise direction; the meshing of the left profile of the left claw rotor and the right profile of the right claw rotor in the synchronous and opposite direction double rotation motion is: the eccentric involute envelope AB meshes with the eccentric involute ab, the left claw tip elliptical arc BC meshes with the right elliptical arc envelope bc, and the left elliptical arc envelope CD meshes with the right claw tip elliptical arc cd.

[0008] A high-efficiency three-claw vacuum pump:

[0009] The equation of the eccentric involute ab on the right profile of the right claw rotor is:

[0010]

[0011] Where: R b is the radius of the involute base circle, h is the eccentricity, and β is the rotation angle of the eccentric involute, which are determined by the following formulas:

[0012]

[0013] The equation of the eccentric involute envelope AB on the left profile of the left-claw rotor is:

[0014]

[0015] Where: α is the first rotation angle, is the first intermediate variable, determined by the following equation:

[0016]

[0017] The equation of the left claw tip elliptical arc BC on the left profile of the left claw rotor is:

[0018]

[0019] in:

[0020] Where: γ is the second rotation angle, m1 is the length of the major semi-axis of the claw tip ellipse arc, and n1 is the length of the minor semi-axis of the claw tip ellipse arc;

[0021] The equation of the left elliptical arc envelope CD on the left profile of the left claw rotor is:

[0022]

[0023] Where: θ is the third rotation angle, is the second intermediate variable, determined by the following equation:

[0024]

[0025] The equation of the right elliptical arc envelope bc on the right profile of the right claw rotor is:

[0026]

[0027] Where: τ is the fourth rotation angle;

[0028] The equation of the right claw tip elliptical arc cd on the right profile of the right claw rotor is:

[0029]

[0030] Where: ε is the fifth rotation angle;

[0031] In the above, R1 is the radius of the circle where the claw top is located; R3 is the radius of the circle where the claw bottom is located; and R2=(R1+R3) / 2 is the radius of the pitch circle.

[0032] The high-efficiency three-claw vacuum pump is provided with an exhaust port on the exhaust end cover, and the contour curve of the exhaust port includes: a bottom edge line EF, a right side line FG, a left side line GE, a left vertex E, a right vertex F, and an upper vertex G; the bottom edge line EF is an eccentric involute, the right side line FG is a straight line, and the left side line GE is an arc.

[0033] The beneficial effects of the present invention are:

[0034] ① In the design of the three-claw rotor profile, the traditional arcs of the claw top and claw bottom are omitted, and the eccentric involute and its envelope are introduced, which solves the problem of large limitations in the selection of design parameters of the three-claw rotor and significantly improves the volumetric efficiency of the three-claw vacuum pump.

[0035] ② The claw tip adopts an elliptical arc line to construct a fully smooth rotor, eliminating the original sharp points, improving leakage at the claw tip and reducing wear at the claw tip.

[0036] ③The profile is simple, consisting of only 4 curves, which facilitates the optimized design of the three-claw vacuum pump. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 This is the structural diagram of the three-claw vacuum pump.

[0038] Figure 2 This is the left-profile diagram of the left-claw rotor.

[0039] Figure 3 This is the right profile diagram of the right claw rotor.

[0040] Figure 4 This is the front view of the exhaust end cover.

[0041] Figure 5 This is the rotor profile meshing diagram.

[0042] Figure 6 This is a picture of the moment when the three-claw vacuum pump finishes suctioning.

[0043] Figure 7 This is a diagram of the moment when compression of the three-claw vacuum pump begins.

[0044] Figure 8 Schematic diagram of claw tip leakage during operation.

[0045] Fig. 9 This is a diagram of the moment when the three-claw vacuum pump starts exhausting.

[0046] Fig.10 This is the picture of the three-claw vacuum pump being exhausted.

[0047] In the figure: 1—left claw rotor; 2—right claw rotor; 3—cavity; 4—exhaust end cover; 101—left mold line; 201—right mold line; 301—intake port; 401—exhaust port; α—first rotation angle; γ—second rotation angle; θ—third rotation angle; τ—fourth rotation angle; ε—fifth rotation angle. DETAILED DESCRIPTION

[0048] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0049] like Figure 1 As shown, it is a structural diagram of a three-claw vacuum pump, including a left-claw rotor 1, a right-claw rotor 2, a cavity 3 and an exhaust end cover 4. The gas enters the cavity 3 through a radial suction port 301 opened on the cavity 3. With the synchronous and opposite-direction double rotational motion of the left-claw rotor 1 and the right-claw rotor 2, the gas sucked into the cavity 3 is transported and compressed at the same volume. When the gas rotates to the exhaust port position, it is discharged axially through the exhaust port 401 opened on the exhaust end cover 4.

[0050] like Figure 2As shown, it is a left-profile diagram of a left-claw rotor. The left profile 101 of the left-claw rotor 1 is 120° centrally symmetrical about its rotation center O1, that is, after the left-claw rotor 1 rotates 120° counterclockwise or clockwise around its rotation center O1, it completely coincides with itself; one third of the left profile 101 of the left-claw rotor 1 is composed of three curves, which are, in clockwise direction: an eccentric involute envelope AB, a left claw tip elliptical arc BC, and a left elliptical arc envelope CD.

[0051] like Figure 3 As shown, it is the right profile diagram of the right claw rotor. The right profile 201 of the right claw rotor 2 is 120° centrally symmetrical about its rotation center O2, that is, after the right claw rotor 2 rotates 120° counterclockwise or clockwise around its rotation center O2, it completely coincides with itself; one third of the right profile 201 of the right claw rotor 2 is composed of three curves, which are: eccentric involute ab, right elliptical arc envelope bc, and right claw tip elliptical arc cd in the counterclockwise direction.

[0052] like Figure 4 As shown, it is a front view of the exhaust end cover, an exhaust port 401 is opened on the exhaust end cover 4, and the contour curve of the exhaust port 401 includes: a bottom edge line EF, a right side line FG, a left side line GE, a left vertex E, a right vertex F, and an upper vertex G; the bottom edge line EF is an eccentric involute, the right side line FG is a straight line, and the left side line GE is an arc.

[0053] like Figure 5 As shown, it is a rotor profile meshing diagram. The meshing conditions of each curve segment of the left profile 101 of the left claw rotor 1 and the right profile 201 of the right claw rotor 2 in the synchronous counter-directional double-rotation motion are as follows: the eccentric involute envelope AB meshes with the eccentric involute ab, the left claw tip elliptical arc BC meshes with the right elliptical arc envelope bc, and the left elliptical arc envelope CD meshes with the right claw tip elliptical arc cd.

[0054] like Figure 6 As shown, this is the moment when the three-claw vacuum pump finishes suctioning. At this time, the volume chamber is no longer connected to the suction port, and the isochoric conveying process is about to begin.

[0055] like Figure 7 As shown, this is the moment when the three-claw vacuum pump starts compression. At this time, the isochoric conveying process ends and the compression process is about to begin.

[0056] like Figure 8 The figure shows the leakage at the claw tip during operation. At this moment, there is a leakage channel when the claw and tip are meshed. The existence of the elliptical arc at the claw tip effectively reduces the leakage at the claw tip.

[0057] like Fig. 9As shown, it is a diagram of the moment when the three-claw vacuum pump starts to exhaust. At this time, a part of the right claw rotor profile coincides with the bottom edge line EF of the exhaust port, indicating that the compression process is over and the exhaust process is about to begin.

[0058] like Fig.10 As shown, the exhaust of the three-claw vacuum pump is about to end. If the rotor continues to rotate past a certain angle, the exhaust port will be completely blocked and the exhaust process will end.

[0059] Although the above describes the specific implementation mode of the present invention in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art on the basis of the technical solution of the present invention without creative work are still within the scope of protection of the present invention.

Claims

1. A high-efficiency three-claw vacuum pump, comprising: A left claw rotor (1), a right claw rotor (2), a cavity (3) and an exhaust end cover (4); wherein the left profile (101) of the left claw rotor (1) is 120° centrally symmetrical about its rotation center O1, i.e., after the left claw rotor (1) rotates 120° counterclockwise or clockwise about its rotation center O1, it completely overlaps with itself; one third of the left profile (101) of the left claw rotor (1) is composed of three curves, which are, in the clockwise direction, an eccentric involute envelope AB, a left claw tip elliptical arc BC, and a left elliptical arc envelope CD; The right profile (201) of the right claw rotor (2) is 120° symmetrical about its rotation center O2, that is, after the right claw rotor (2) rotates 120° counterclockwise or clockwise around its rotation center O2, it completely overlaps with itself; one third of the right profile (201) of the right claw rotor (2) is composed of three curves, which are: eccentric involute ab, right elliptical arc envelope bc, and right claw tip elliptical arc cd in the counterclockwise direction; the meshing conditions of the curves of the left profile (101) of the left claw rotor (1) and the right profile (201) of the right claw rotor (2) in the synchronous and opposite direction double rotation motion are: the eccentric involute envelope AB meshes with the eccentric involute ab, the left claw tip elliptical arc BC meshes with the right elliptical arc envelope bc, and the left elliptical arc envelope CD meshes with the right claw tip elliptical arc cd; The equation of the eccentric involute ab on the right profile (201) of the right claw rotor (2) is: Where: R b is the radius of the involute base circle, h is the eccentricity, and β is the rotation angle of the eccentric involute, which are determined by the following formulas: The equation of the eccentric involute envelope AB on the left profile (101) of the left claw rotor (1) is: Where: α is the first rotation angle, is the first intermediate variable, determined by the following equation: The equation of the left claw tip elliptical arc BC on the left mold line (101) of the left claw type rotor (1) is: in: Where: γ is the second rotation angle, m1 is the length of the major semi-axis of the claw tip ellipse arc, and n1 is the length of the minor semi-axis of the claw tip ellipse arc; The equation of the left elliptical arc envelope CD on the left profile (101) of the left claw rotor (1) is: Where: θ is the third rotation angle, is the second intermediate variable, determined by the following equation: The equation of the right elliptical arc envelope bc on the right profile (201) of the right claw rotor (2) is: Where: τ is the fourth rotation angle; The equation of the right claw tip elliptical arc cd on the right mold line (201) of the right claw type rotor (2) is: Where: ε is the fifth rotation angle; In the above, R1 is the radius of the circle where the claw top is located; R3 is the radius of the circle where the claw bottom is located; and R2=(R1+R3) / 2 is the radius of the pitch circle.

2. A high-efficiency three-claw vacuum pump as claimed in claim 1, characterized in that: An exhaust port (401) is provided on the exhaust end cover (4), and the contour curve of the exhaust port (401) includes: a bottom edge line EF, a right side line FG, a left side line GE, a left vertex E, a right vertex F, and an upper vertex G; the bottom edge line EF is an eccentric involute, the right side line FG is a straight line, and the left side line GE is an arc.

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