Multi-blade roots pump rotor molded line

The invention belongs to the field of fluid machinery, particularly relates to a multi-blade roots pump rotor molded line, and aims to solve the problem that in the prior art, the molded line design is limited when the ratio of the center distance A to the rotor diameter D (A/D) of an involute-pin tooth circular-arc rotor molded line in the prior art is less than a limit value. The multi-blade roots pump rotor molded line provided by the invention comprises a first rotor and a second rotor, wherein the first rotor and the second rotor are used cooperatively; the molded line of the first rotorcomprises a first tooth top rolling circular-arc segment, a first circular-arc segment, a first involute segment, a first circular-arc envelope segment, a first point meshing cycloid segment and a first tooth root rolling circular-arc segment in sequence; and the molded line of the second rotor comprises a second tooth top rolling circular-arc segment, a second circular-arc segment, a second involute segment, a second cir