Tooth profile of a twin-screw compressor rotor

Abstract

The present invention discloses a tooth profile of a twin-screw compressor rotor. The twin-screw compressor includes a female rotor and a male rotor. The tooth profile of the female rotor end face is formed by six segments of curves smoothly connected end to end, and the tooth profile of the male rotor end face is formed by six segments of curves smoothly connected end to end. The tooth curves of the male rotor end face include circular arcs, circular arc envelopes, and elliptical arc envelopes; the tooth curves of the female rotor end face include circular arcs, circular arc envelopes, and elliptical arcs. After adopting the above technical solution, since the male rotor and the female rotor can achieve optimal meshing during operation, the tooth curves of two adjacent segments smoothly transition at the connection point, the rotor area utilization coefficient is relatively large, the contact line is short, the leakage triangle is relatively small, the profile is streamlined, and the compressor has good thermodynamic properties, thereby improving the working efficiency of the screw compressor.

Description

Technical Field

[0001] The invention relates to a rotor end face tooth profile of a screw compressor, and in particular to a rotor profile of a twin-screw compressor. Background Art

[0002] Screw compressors are widely used in industries such as refrigeration, mining, and petrochemicals due to their high reliability, good dynamic balance, low leakage, and high efficiency. The rotor of a twin-screw compressor has a crucial impact on overall unit performance, and the rotor profile directly determines this performance. Therefore, the optimal design of a screw compressor depends primarily on the rotor profile design. Existing high-performing rotor profiles for twin-screw compressors abroad primarily include the German GHH profile, the Japanese Hitachi profile, and the Swedish SRM-D asymmetric profile. These profiles lack optimal balance in geometric characteristics such as a small leakage triangle area, a large inter-tooth area, and a short contact line. Simultaneously improving these geometrical characteristics will ultimately lead to an optimized rotor profile design, resulting in a larger internal flow area and lower leakage in the twin-screw compressor. Furthermore, this will minimize internal gas pulsation caused by the relative motion of the male and female rotors, resulting in lower compressor noise during operation and ultimately improving the efficiency of the twin-screw compressor. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a screw compressor rotor tooth profile. A compressor with this tooth profile can achieve optimal meshing between the male rotor and the female rotor during operation, and the tooth curves of two adjacent sections transition smoothly at the connection point. The number of rotor teeth is relatively large, and it can withstand a relatively large pressure difference. The rotor area utilization coefficient is relatively large, the contact line is short, and the leakage triangle is relatively small. The female rotor profile is streamlined, which reduces the pulsation of gas inside the compressor, thereby improving the working efficiency of the screw compressor.

[0004] According to the tooth profile of the twin-screw compressor rotor of an embodiment of the present invention, the twin-screw compressor includes a female rotor and a male rotor, and is characterized in that each tooth profile on the end face of the female rotor is formed by six segments of curves smoothly connected end to end, and each tooth profile on the end face of the male rotor is formed by six segments of curves smoothly connected end to end, wherein: the tooth curve on the end face of the male rotor includes a circular arc line, a circular arc envelope line and an elliptical arc envelope line; the tooth curve on the end face of the female rotor includes a circular arc line, a circular arc envelope line and an elliptical arc line.

[0005] The embodiment of the present invention combines the geometric method with the particle swarm algorithm to design a new screw compressor rotor tooth profile. Compared with other profiles, this rotor profile has the following advantages:

[0006] 1. The streamlined design of the female rotor in the embodiment of the present invention reduces airflow disturbance resistance, minimizes losses, reduces noise, and improves rotor efficiency. Under high temperatures, the rotor expands, resulting in uneven clearance between the female and male rotors. The female rotor's tooth profile, composed of circular envelopes, circular arcs, and elliptical arcs, makes it easier to adjust the gap to accommodate any unevenness.

[0007] 2. Since the female rotor of the embodiment of the present invention adopts a relatively suitable tooth depth radius, it is very suitable for compressors with large flow rates, while retaining a relatively deep tooth thickness, so that the rotor achieves relatively good rigidity conditions;

[0008] 3. The embodiment of the present invention optimizes the rotor profile, so that the contact line length is relatively small, the leakage triangle area is minimized as much as possible, the leakage of the compressor is greatly reduced, and the relative volumetric efficiency is relatively high. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 It is a schematic diagram of an embodiment of the female rotor and the male rotor of the present invention when they are meshed with each other.

[0010] Figure 2 It is a schematic diagram of the tooth profile of the female rotor of the present invention.

[0011] Figure 3 Schematic diagram of the tooth profile of the male rotor of the present invention.

[0012] In the figure: O1 is the axis of the male rotor, O2 is the axis of the female rotor; Mj is the pitch circle of the male rotor, R1 is the pitch circle radius of the male rotor; Fj is the pitch circle of the female rotor, R2 is the pitch circle radius of the female rotor; A is the center distance between the two rotors, A=R1+R2; O3 is the center of the female rotor arc A2B2, R3 is the radius of the female rotor arc A2B2; O4 is the center of the female rotor arc B2C2, R4 is the radius of the female rotor arc B2C2; O5 is the center of the female rotor elliptical arc C2D2; O6 is the center of the female rotor arc E2A2, R6 is the radius of the female rotor arc E2A2; O7 is the center of the female rotor arc F2E2, R7 is the radius of the female rotor arc E2F2; O8 is the center of the male rotor arc G1F1, R8 is the radius of the male rotor arc G1F1. DETAILED DESCRIPTION

[0013] The tooth profile of the twin-screw compressor rotor of the present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0014] See also Figures 1 to 3 The rotor tooth profiles of the female rotor F and the male rotor M of the twin-screw compressor of the present invention are bilaterally asymmetric, and the number of teeth on the female rotor F is greater than the number of teeth on the male rotor M. In this embodiment, the gear ratio of the male rotor M to the female rotor F is 4:5.

[0015] According to an embodiment of the present invention, the tooth profile of a dry twin-screw compressor rotor includes a female rotor F and a male rotor M. Each tooth profile on the end surface of the female rotor F is formed by six smoothly connected curve segments, and each tooth profile on the end surface of the male rotor M is formed by six smoothly connected curve segments. The tooth curves on the male rotor end surface include circular arcs, circular arc envelopes, and elliptical arc envelopes; and the tooth curves on the female rotor end surface include circular arcs, circular arc envelopes, and elliptical arcs. In this embodiment: the tooth curves of each tooth profile on the end face of the female rotor include the following smoothly connected sequences: the circular arc envelope G2F2, the circular arc F2E2, the circular arc E2A2, the circular arc A2B2, the circular arc B2C2, and the elliptical arc C2D2; the tooth curves of each tooth profile of the male rotor include the following smoothly connected sequences: the circular arc G1F1, the circular arc envelope F1E1, the circular arc envelope E1A1, the circular arc envelope A1B1, the circular arc envelope B1C1, and the elliptical arc envelope C1D1.

[0016] The arc envelope G2F2 of each tooth profile of the female rotor is a segment of the arc envelope formed by the trajectory formed by the female rotor pitch circle moving relative to the male rotor arc G1F1 when rolling along the male rotor pitch circle. The arc G1F1 of each tooth profile of the male rotor is an arc with a center point O8 outside the female rotor pitch circle and a radius n7 times the male rotor pitch circle radius, where n7 is a positive number greater than 0.5 and less than or equal to 0.7. The arc G1F1 smoothly connects to the endpoint of the adjacent male rotor tooth at its starting point G1 and smoothly connects to the arc envelope F1E1 at its endpoint F1.

[0017] The arc F2E2 of each tooth profile of the female rotor is an arc centered at O7 outside the female rotor pitch circle and having a radius n1 times the female rotor pitch circle radius, where n1 is a positive number greater than 0.5 and less than or equal to 0.7. Arc F2E2 is tangentially connected to the arc envelope G2F2 at its starting point F2 and smoothly connected to arc E2A2 at its end point E2. The arc envelope F1E1 of each tooth profile of the male rotor is an arc envelope formed by the trajectory formed by the male rotor pitch circle rolling along the female rotor pitch circle relative to the female rotor arc F2E2.

[0018] The arc E2A2 of each tooth profile of the female rotor is an arc centered at O6 outside the male rotor pitch circle and having a radius n2 times the radius of the female rotor pitch circle, where n2 is a positive number greater than 0.2 and less than or equal to 0.3. Arc E2A2 is tangentially connected to arc F2E2 at starting point E2 and smoothly connected to arc A2B2 at end point A2. The arc envelope E1A1 of each tooth profile of the male rotor is an arc envelope formed by the trajectory formed by the male rotor pitch circle rolling along the female rotor pitch circle relative to the female rotor arc E2A2.

[0019] Arc A2B2 of each tooth profile of the female rotor is an arc centered at O3 within the female rotor pitch circle and having a radius n3 times the female rotor pitch circle radius, where n3 is a positive number greater than 0.3 and less than or equal to 0.6. Arc A2B2 smoothly connects to arc E2A2 at starting point A2 and tangentially connects to arc B2C2 at end point B2. Arc envelope A1B1 of each tooth profile of the male rotor is an arc envelope formed by the trajectory formed by the male rotor pitch circle rolling along the female rotor pitch circle relative to arc A2B2 of the female rotor.

[0020] The arc B2C2 of each tooth profile of the female rotor is centered at O4 inside the female rotor pitch circle and has a radius of n4 times the female rotor pitch circle radius, where n4 is a positive number greater than 0.7 and less than or equal to 0.9. Arc B2C2 smoothly connects to arc A2B2 at starting point B2 and tangentially connects to elliptical arc C2D2 at end point C2. The arc envelope B1C1 of each tooth profile of the male rotor is the arc envelope formed by the trajectory formed by the male rotor pitch circle rolling along the female rotor pitch circle relative to the female rotor arc B2C2.

[0021] The elliptical arc C2D2 of each tooth profile of the female rotor is centered at O5 inside the pitch circle of the female rotor, with a major axis of n5 times the pitch circle radius of the female rotor and a minor axis of n6 times the pitch circle radius of the female rotor, where n5 is a positive number greater than 0.5 and less than or equal to 0.8, and n6 is a positive number greater than 0.3 and less than or equal to 0.5; the elliptical arc C2D2 is smoothly connected to the arc B2C2 at the starting point C2, and is tangentially connected to the starting point of another adjacent tooth of the female rotor at the end point D2; the elliptical arc envelope C1D1 of each tooth profile of the male rotor is an elliptical arc envelope of the trajectory formed by the movement of the male rotor pitch circle relative to the female rotor elliptical arc C2D2 when rolling along the pitch circle of the female rotor.

[0022] Compared with the prior art, the end face tooth profiles of the female and male rotors in the embodiment of the present invention have an area utilization coefficient increased by 8.54% while reducing the contact line length by 11.67%, and a leakage triangle area reduced by 4.35%. This increases the area utilization coefficient of the tooth profile, reduces rotor leakage, and increases the pressure difference that the compressor can withstand. The embodiment is particularly suitable for high-temperature and high-flow working conditions.

Claims

1. The tooth profile of a twin-screw compressor rotor, wherein the twin-screw compressor comprises a female rotor and a male rotor, characterized in that: Each tooth profile on the end surface of the female rotor is formed by six curve segments smoothly connected end to end, and each tooth profile on the end surface of the male rotor is formed by six curve segments smoothly connected end to end, wherein: the tooth curves on the end surface of the male rotor include circular arcs, circular arc envelopes, and elliptical arc envelopes; the tooth curves on the end surface of the female rotor include circular arcs, circular arc envelopes, and elliptical arcs; The tooth curves of each tooth profile of the female rotor include the following smoothly connected arc envelopes G2F2, arc F2E2, arc E2A2, arc A2B2, arc B2C2, and elliptical arc C2D2; The tooth curves of each tooth profile of the male rotor include the following smoothly connected in sequence: circular arc G1F1, circular arc envelope F1E1, circular arc envelope E1A1, circular arc envelope A1B1, circular arc envelope B1C1 and elliptical arc envelope C1D1; In the tooth curves of each tooth type of the female rotor: The arc envelope G2F2 is a segment of the arc envelope formed by the movement of the female rotor pitch circle relative to the male rotor arc G1F1 when the female rotor pitch circle rolls along the male rotor pitch circle; Arc F2E2 is an arc centered at O7 outside the pitch circle of the female rotor and having a radius n1 times the pitch circle radius of the female rotor, where n1 is a positive number greater than 0.5 and less than or equal to 0.

7. Arc F2E2 is tangent to the arc envelope G2F2 at its starting point F2 and smoothly connects to arc E2A2 at its end point E2. Arc E2A2 is an arc centered at O6 outside the male rotor pitch circle and having a radius n2 times the female rotor pitch circle radius, where n2 is a positive number greater than 0.2 and less than or equal to 0.

3. Arc E2A2 is tangent to arc F2E2 at its starting point E2 and smoothly connects to arc A2B2 at its end point A2. Arc A2B2 is an arc centered at O3 inside the pitch circle of the female rotor and having a radius n3 times the pitch circle radius of the female rotor, where n3 is a positive number greater than 0.3 and less than or equal to 0.

6. Arc A2B2 smoothly connects to arc E2A2 at starting point A2 and tangentially connects to arc B2C2 at end point B2. Arc B2C2 is an arc with O4 inside the pitch circle of the female rotor as its center and a radius of n4 times the pitch circle radius of the female rotor, where n4 is a positive number greater than 0.7 and less than or equal to 0.

9. Arc B2C2 smoothly connects to arc A2B2 at its starting point B2 and tangently connects to elliptical arc C2D2 at its end point C2. The elliptical arc C2D2 is centered at O5 inside the pitch circle of the female rotor, with a major axis of n5 times the pitch circle radius of the female rotor and a minor axis of n6 times the pitch circle radius of the female rotor, where n5 is a positive number greater than 0.5 and less than or equal to 0.8, and n6 is a positive number greater than 0.3 and less than or equal to 0.5; the elliptical arc C2D2 is smoothly connected to the circular arc B2C2 at the starting point C2, and is tangently connected to the starting point of another adjacent tooth of the female rotor at the end point D2.

2. The tooth profile of the twin-screw compressor rotor according to claim 1, characterized in that: In the tooth curves of each tooth profile of the male rotor: Arc G1F1 is an arc with its center at O8 outside the female rotor pitch circle and a radius of n7 times the male rotor pitch circle radius, where n7 is a positive number greater than 0.5 and less than or equal to 0.

7. Arc G1F1 is smoothly connected to the end point of another adjacent tooth on the male rotor at its starting point G1, and is smoothly connected to the arc envelope F1E1 at its end point F1. The arc envelope F1E1 is a segment of the arc envelope formed by the movement of the male rotor pitch circle relative to the female rotor arc F2E2 when the male rotor pitch circle rolls along the female rotor pitch circle; The arc envelope E1A1 is a segment of the arc envelope formed by the movement of the male rotor pitch circle relative to the female rotor arc E2A2 when the male rotor pitch circle rolls along the female rotor pitch circle; The arc envelope A1B1 is a segment of the arc envelope formed by the movement of the male rotor pitch circle relative to the female rotor arc A2B2 when the male rotor pitch circle rolls along the female rotor pitch circle; The arc envelope B1C1 is a segment of the arc envelope formed by the movement of the male rotor pitch circle relative to the female rotor arc B2C2 when the male rotor pitch circle rolls along the female rotor pitch circle; The elliptical arc envelope C1D1 is a segment of the elliptical arc envelope of a trajectory formed by the movement of the male rotor pitch circle relative to the female rotor elliptical arc C2D2 when the male rotor pitch circle rolls along the female rotor pitch circle.

3. The tooth profile of the twin-screw compressor rotor according to claim 1, characterized in that: The rotor tooth profiles of the female rotor and the male rotor are bilaterally asymmetric, and the number of teeth on the female rotor is greater than that on the male rotor.

4. The tooth profile of the twin-screw compressor rotor according to claim 1, characterized in that: The gear ratio of the male rotor to the female rotor is 4:5.

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