Patent ID: 6296461
Filing Date: 2001-10-02
Classification: F04C,Y10T

Abstract:
A plural screw, positive displacement machine, said machine comprising:a housing having at least two intersecting bores; anda male rotor and a female rotor mounted for rotation in said housing wherein, each said rotor has an axis and a pitch circle that extends around the axis and wherein:each said rotor is located in a separate one of the bores of said;said male rotor is formed with a plurality of circumferentially spaced apart lobes, each said lobe extending outwardly beyond the pitch circle of said male rotor and helically along said male rotor;said female rotor is formed with a plurality of circumferentially spaced apart lobes that define depressions that extend inwardly from an outer surface of said female rotor and inwardly relative to the pitch circle of said female rotor and helically along said female rotor;said housing is shaped and said rotors are positioned so that said lobes of said male rotor mesh into the depressions of said female rotor; andsaid lobes of said male rotor are defined by curving a rack about the axis of said male rotor and the depressions of said female rotor are defined by curving the rack around the axis of said female rotor and the rack has a cycloidal portion which defines a major portion of a first flank of each said lobe of each said rotor.