Screw vacuum pump rotor and screw vacuum pump thereof

Abstract

The invention relates to the field of screw vacuum pumps, and discloses a screw vacuum pump rotor and a screw vacuum pump thereof, which are characterized in that the molded line of the rotor consists of five sections of curves which are sequentially connected end to end, namely a screw tip circle AB with the radius of R, an eccentric Bernoulli lemniscate BC and a conjugate envelope line CD of the eccentric Bernoulli lemniscate BC in sequence in the anticlockwise direction, compared with an eccentric heart-shaped line, an eccentric Bernoulli lemniscate, a screw root circle DE with the radius of r, an extended epicycloid EA and an eccentric Bernoulli lemniscate have the advantages that the change rate of the curvature radius of the section AB is larger, the eccentric Bernoulli lemniscate is more adaptive to a screw vacuum pump rotor with the larger difference between the addendum circle radius and the root circle radius, and the transition between the two rotors is more stable; the eccentricity # imgabs0 # and the area utilization coefficient c of the eccentric Bernoulli lemniscate AB can be actively adjusted, the area utilization coefficient can be well improved, and the design parameter space of the screw vacuum pump rotor profile with the larger difference between the addendum circle radius and the dedendum circle radius is improved.

Description

Technical Field

[0001] The present invention relates to the field of screw vacuum pumps, and more particularly to a screw vacuum pump rotor and a screw vacuum pump thereof. Background Art

[0002] The core component of the twin-screw vacuum pump is a pair of non-contact screw rotors that mesh with each other. The two screws are finely balanced, supported by bearings, and installed in the pump housing. There is a certain gap between the screws.

[0003] Therefore, the design of the screw rotor needs to achieve synchronous meshing motion without tooth surface interference. The screw rotor profile will directly affect the performance of the screw pump.

[0004] The existing traditional twin-screw vacuum pump rotor profile is difficult to adapt to screw vacuum pump rotors with a larger difference between the tooth top circle radius and the tooth root circle radius. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the object of the present invention is to provide a screw vacuum pump rotor and a screw vacuum pump thereof, which can better adapt to screw vacuum pump rotors with a larger difference between the tooth top circle radius and the tooth root circle radius.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a screw vacuum pump rotor, wherein the rotor profile consists of five curve segments connected end to end, which are, in a counterclockwise direction, the screw tip circle AB with a radius R, the eccentric Bernoulli lemniscate BC, the conjugate envelope CD of the eccentric Bernoulli lemniscate BC, the screw root circle DE with a radius r, and the extended epicycloid EA;

[0007] The eccentric Bernoulli lemniscate BC is smoothly connected to the screw top circle AB, the eccentric Bernoulli lemniscate BC is smoothly connected to the conjugate envelope CD, and the conjugate envelope CD is smoothly connected to the screw root circle DE;

[0008] The coordinate equation of the eccentric Bernoulli lemniscate BC is:

[0009]

[0010] Where, is the parameter variable, is the eccentricity, R is the screw top circle radius, and c is the area utilization coefficient.

[0011] As a further improvement of the present invention, the coordinate equation of the conjugate envelope CD of the eccentric Bernoulli lemniscate BC is:

[0012]

[0013] In the formula, A=R+r, A is a constant, which expresses the center distance between the two screw rotors. is the parameter variable, is the eccentricity, R is the screw top circle radius, and c is the area utilization coefficient;

[0014] yes The function of = Determined.

[0015] As a further improvement of the present invention, the coordinate equation of the extended epicycloid EA is:

[0016]

[0017] Where, is the parameter variable.

[0018] As a further improvement of the present invention, the eccentric Bernoulli lemniscate BC is tangent to the screw top circle AB at point B, and the eccentric Bernoulli lemniscate BC intersects with the conjugate envelope CD at point C on the pitch circle and is tangent to the point C.

[0019] As a further improvement of the present invention, Equal to the pitch radius of the screw rotor.

[0020] A screw vacuum pump comprises two of the above-mentioned screw vacuum pump rotors, wherein the two rotors have the same profile.

[0021] Beneficial effects of the present invention: Compared with the eccentric core line, the eccentric Bernoulli lemniscate in the present invention has a greater rate of change in the curvature radius of the AB segment, is more suitable for the screw vacuum pump rotor with a larger difference between the tooth tip circle radius and the tooth root circle radius, and makes the transition between the two rotors smoother; the eccentricity of the eccentric Bernoulli lemniscate AB can also be actively adjusted And the area utilization coefficient c, can greatly improve the area utilization coefficient, and increase the design parameter space for the screw vacuum pump rotor profile with a larger difference between the tooth top circle radius and the tooth root circle radius. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 Schematic diagram of the rotor profile of the present invention;

[0023] Figure 2 Schematic diagram of the formation of the eccentric Bernoulli lemniscate BC in the present invention;

[0024] Figure 3 The rotor profile of the present invention is Schematic diagram of the comparison. DETAILED DESCRIPTION

[0025] The present invention will be described in further detail below with reference to the accompanying drawings and embodiments. Identical components are denoted by the same reference numerals. It should be noted that the terms "front," "rear," "left," "right," "upper," and "lower" used in the following description refer to directions in the accompanying drawings, and the terms "bottom," "top," "inner," and "outer" refer to directions toward or away from the geometric center of a particular component, respectively.

[0026] Reference Figures 1 to 3 As shown, a screw vacuum pump rotor of this embodiment has a profile composed of five curve segments connected end to end, which are, in a counterclockwise direction, the screw top circle AB with a radius of R, the eccentric Bernoulli lemniscate BC, the conjugate envelope CD of the eccentric Bernoulli lemniscate BC, the screw root circle DE with a radius of r, and the extended epicycloid EA.

[0027] The eccentric Bernoulli lemniscate BC is smoothly connected to the screw top circle AB, the eccentric Bernoulli lemniscate BC is smoothly connected to the conjugate envelope CD, and the conjugate envelope CD is smoothly connected to the screw root circle DE;

[0028] The coordinate equation of the eccentric Bernoulli lemniscate BC is:

[0029]

[0030] Where, is the parameter variable, is the eccentricity, R is the screw top circle radius, and c is the area utilization coefficient.

[0031] A rectangular coordinate system is established with the center of the screw top circle AB with a radius of R as the circle point and OB as the X-axis; the line segment OA and the line segment OC are located on a straight line and coincide with the 45-degree oblique line on the pitch circle.

[0032] The formation process of the eccentric Bernoulli lemniscate BC is as follows: The intersection point in is the origin, and a rectangular coordinate system is established. The standard Bernoulli lemniscate By simple translation, without rotation, the center point is translated to point (- , 0), so that the Bernoulli lemniscate after translation It is tangent to the top circle of the screw at point B, and passes through the intersection of the pitch circle and the 45-degree oblique line, retaining this part of the line segment to form an eccentric Bernoulli lemniscate AB.

[0033] Compared with the eccentric heartline, the eccentric Bernoulli lemniscate has a larger rate of change in the curvature radius of the AB segment, is more suitable for the screw vacuum pump rotor with a larger difference between the tooth top circle radius and the tooth root circle radius, and makes the transition between the two rotors smoother.

[0034] The rotor profile of the present invention can also actively adjust the eccentricity of the eccentric Bernoulli lemniscate AB And the area utilization coefficient c, can greatly improve the area utilization coefficient, and increase the design parameter space for the screw vacuum pump rotor profile with a larger difference between the tooth top circle radius and the tooth root circle radius.

[0035] Reference Figure 2 As shown, the coordinate equation of the conjugate envelope CD of the eccentric Bernoulli lemniscate BC is:

[0036]

[0037] In the formula, A=R+r, A is a constant, which expresses the center distance between the two screw rotors. is the eccentricity, R is the screw top circle radius, and c is the area utilization coefficient;

[0038] Preferably, Equal to the pitch radius of the screw rotor.

[0039] yes The function of = Determined.

[0040] The coordinate equation of the extended epicycloid EA is:

[0041]

[0042] Where, is the parameter variable.

[0043] The eccentric Bernoulli lemniscate BC is tangent to the screw top circle AB at point B. The eccentric Bernoulli lemniscate BC intersects and is tangent to the conjugate envelope CD at point C on the pitch circle. Because the eccentric Bernoulli lemniscate BC is smooth and tangent at point B, the leakage triangle is completely eliminated, minimizing leakage between the front and rear stages of the screw rotor, as well as between the screw rotor and the pump chamber.

[0044] A screw vacuum pump comprises two of the above-mentioned screw vacuum pump rotors, wherein the two rotors have the same profile.

[0045] The above are merely preferred embodiments of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions based on the principles of the present invention are within the scope of protection of the present invention. It should be noted that improvements and modifications that do not depart from the principles of the present invention are within the scope of protection of the present invention.

Claims

1. A screw vacuum pump rotor, characterized in that: The rotor profile consists of five curves connected end to end, which are, in counterclockwise direction, the screw top circle AB with a radius of R, the eccentric Bernoulli lemniscate BC, the conjugate envelope CD of the eccentric Bernoulli lemniscate BC, the screw root circle DE with a radius of r, and the extended epicycloid EA. The eccentric Bernoulli lemniscate BC is smoothly connected to the screw top circle AB, the eccentric Bernoulli lemniscate BC is smoothly connected to the conjugate envelope CD, and the conjugate envelope CD is smoothly connected to the screw root circle DE; The coordinate equation of the eccentric Bernoulli lemniscate BC is: Where, is the parameter variable, is the eccentricity, R is the screw top circle radius, and c is the area utilization coefficient; The coordinate equation of the conjugate envelope CD of the eccentric Bernoulli lemniscate BC is: Where A=R+r, A is a constant that represents the center distance between the two screw rotors; yes The function of = determined; The coordinate equation of the extended epicycloid EA is: 。 2. A screw vacuum pump rotor according to claim 1, characterized in that: The eccentric Bernoulli lemniscate BC is tangent to the screw top circle AB at point B. The eccentric Bernoulli lemniscate BC intersects with the conjugate envelope CD at point C on the pitch circle and is tangent to the conjugate envelope CD at point C.

3. The screw vacuum pump rotor according to claim 1, characterized in that: Equal to the pitch radius of the screw rotor.

4. A screw vacuum pump, characterized in that: The invention comprises two screw vacuum pump rotors according to any one of claims 1 to 3, wherein the profiles of the two rotors are consistent.

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