Twin-screw vacuum pump rotor profile

The invention discloses a twin-screw vacuum pump rotor profile which includes a point gearing cycloid, a gear root arc, an Archimedean spiral like curve, a conjugate envelope of the Archimedean spiral like curve and a gear top arc. The twin-screw vacuum pump rotor profile provided by the invention is simple in curve composition, the Archimedean spiral like curve is determined through the continuity of the first order derivative of the arc, and the conjugate envelope of the Archimedean spiral like curve is added; each curve section is smoothly connected, and completely meets the meshing theorem; the win-screw vacuum pump rotor profile has the characteristics of being small in leakage triangle, small in through-hole area and high in volumetric efficiency; the designed two screw rotor profiles are the same, so that the processing cost of the rotor is reduced; according to the invention, cycloid or arc correction is further carried out on the cuspidal point formed by the cycloid section and the gear top arc section through crossing, and the cuspidal point of the profile is eliminated, so that the service life of the rotor is prolonged, and the working efficiency of the twin-screw vacuum pump is increased.