Self-balancing conical screw rotor

Abstract

The invention discloses a self-balancing conical screw rotor. The screw rotor is characterized in that the screw rotor is integrally conical; from an air suction end (I-I) to an exhaust end (VII-VII), the tooth crest circular arc radius R1 of the rotor is gradually decreased, and the tooth root circular arc radius R3 of the rotor is gradually increased; the tooth crest thickness delta 1 and the tooth root thickness delta 2 of the screw rotor remain unchanged in the axial direction; section molded lines change at arbitrary axial positions; 12 curves composed of the section molded lines are the same in type; and the adjacent curves are completely smoothly connected. According to the self-balancing varying pitch conical screw rotor provided by the invention, the volume of working chambers of the air suction ends can be effectively increased, the volume of working chambers of the exhaust ends is decreased, the rotor has relatively large interior volume specific ratio, and the interstage sealing performance of the exhaust ends and the strength of the rotor are guaranteed; and centroids of the section molded lines at arbitrary axial positions of the screw rotor are on a rotation central line of the screw rotor, and the dynamic balance performance of the screw rotor is good.

Description

technical field [0001] The invention relates to a twin-screw vacuum pump, in particular to a self-balancing conical screw rotor suitable for the twin-screw vacuum pump. Background technique [0002] The twin-screw vacuum pump is a positive displacement vacuum pump, which is widely used in petrochemical, food and pharmaceutical, vacuum heat treatment, nano-manufacturing, and national defense technology fields because of its dry, oil-free suction chamber and stable and reliable operation; the twin-screw vacuum pump passes two The synchronous and opposite double-rotational motion of the two screw rotors completes the suction, transportation, compression and exhaust process of the gas in the pump chamber; the performance of the screw rotor and its cross-sectional profile directly affects the interstage sealing performance and mechanics of the screw vacuum pump. performance and ultimate vacuum. [0003] The single-head conical screw rotor disclosed in patent CN101351646 has a la...

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Problems solved by technology

[0004] In order to solve the eccentric force of the screw rotor in the above literature, the cusp of the section line, the large thickness of the tooth top at the suction end occupies the suction volume, and the small thickness of the tooth top at the exhaust end makes the gas pass through the interstage leakage of the tooth top surface. The larger problem, in order to enrich the types of screw rotors, the present invention proposes a self-balancing conical screw rotor; the screw rotor is conical, from the suction end (I-I) to the exhaust end (VII-VII), The cross-sectional profile of the screw rotor changes; the lead P of the screw rotor remains unchanged along the axial direction, and the thickness of the addendum δ of the screw rotor is controlled by controlling the central angle α of the addendum arc of the screw rotor 1 and root thickness δ 2 Always constant and equal, thus increasing the suction volume of the screw rotor at the suction end (I-I), effectively blocking the gas between two adjacent working chambers at the exhaust end (VII-VII) of the screw rotor Through the interstage leakage of the top surface of the tooth, the strength of the screw rotor at the exhaust end (VII-VII) is increased and the deformation is reduced; the cross-sectional profile of the screw rotor is smooth and can achieve correct meshing, Eliminate the bad influence of the rough connection point, and improve the stress condition of the screw rotor; at any axial position of the proposed screw rotor, its cross-sectional profile is S-shaped, and the centroid of the cross-sectional profile is in the rotation of the screw rotor On the center line, the screw rotor has good dynamic balance performance; the proposed screw rotor can increase the volume of the working chamber at the suction end, reduce the volume of the working chamber at the exhaust end, increase the internal volume ratio during the working process, and improve The pumping speed and ultimate vacuum of the twin-screw vacuum pump

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