Screw rotor without acute-angle cusp

Abstract

The invention discloses a screw rotor without an acute-angle cusp, and belongs to the technical field of dry-type double-screw vacuum pumps. A screw rotor end face profile is composed of six curves, and the other adjacent curves are in smooth connection except that the circle involute AB and the tooth crest arc BC are in non-smooth connection. The tooth crest arc BC and the tooth root arc EF are in smooth connection by the adoption of the arc CD and the equidistant curve DE of the cycloid, and the acute-angle cusp in an original screw rotor end face profile is eliminated. In work, the two screw rotor end face profiles are identical and can be accurately engaged. Thus, the screw rotor generated by the screw rotor end face profile is composed of six tooth surfaces, the other adjacent tooth surfaces are in smooth connection except that the tooth crest surface (11) and the oblique tooth surface (13) are in non-smooth connection, and no acute-angle edge exists. The screw rotor has the advantages of being simple in structure, high in strength, good in leakproofness and long in service life.

Description

technical field [0001] The invention relates to a dry-type twin-screw vacuum pump, in particular to a screw rotor without acute angle point suitable for the dry-type twin-screw vacuum pump. Background technique [0002] The dry twin-screw vacuum pump is a positive displacement vacuum pump, which forms a periodically changing working chamber volume between the two screw rotors and the inner cavity of the pump through the synchronous counter-rotating double-rotation motion of two screw rotors that can be meshed. Realize the suction, pressurization and discharge of gas, and form a vacuum at the inlet of the pump; the screw rotor is generated by the spiral expansion of the end surface of the screw rotor along the axial direction; therefore, the performance of the end surface of the screw rotor and the two screw rotors The conjugate meshing performance between the end surface profiles directly affects the performance of the screw rotor and the performance of the twin-screw vacuum...

AI Technical Summary

Problems solved by technology

[0004] In the profiled line of the above-mentioned screw rotor end surface, the arc of the addendum and the arc of the root are connected by a long cycloid. However, the connection between the arc of the addendum and the long cycloid is not smooth, and the angle formed is very small, which is an acute angle. point; the screw rotor generated by the end surface profile line of the screw rotor with an acute point has a very sharp edge. Such a sharp edge is easy to wear during work. During the processing of the screw rotor, this sharp The edges of the twin-screw vacuum pump are usually chamfered or rounded, thus losing the meshing performance of the profile, which has a great impact on the performance of the screw rotor, resulting in poor gas sealing performance and large gas leakage, which ultimately affects the ultimate vacuum of the twin-screw vacuum pump. speed and pumping speed

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