SCREW ROTORS

摘要

Screw rotors having nonsymmetrical tooth profiles and used in a screw-type rotary compressor or expander. The tooth profile of the female rotor is formed such that a line (H2-A2) is formed by a generated curve of a point A1 of the male rotor; a line (A2-B2) is formed by a circular arc having a point O7 as the center of the arc and a radius R7; a line (B2-C'2) is formed by an envelope developed by a circular arc (B1-C1) of the male rotor; a portion between points D'2 and E2 is formed by a circular arc having a point O1 as the center of the arc and a radius R1; a line (C'-D') is formed by a line smoothly connecting the lines (B2-C'2) and (D'2-E2); a line (E2-F2) is formed by a circular arc having a point O2 as the center of the arc and a radius R2; and a line (F2-G2) is formed by a circular arc having a point O8 as the center of the arc and a radius R8. The tooth profile of the male rotor is formed such that a line (H1-A1) is formed by a generated curve of a point H2 of the female rotor; a line (A1-B1) is formed by an envelope developed by the arc (A2-B2) of the female rotor; a line (B1-C1) is formed by a circular arc having a point O4 as the center of the arc and a radius R4; a line (C1-D1) is formed by a circular arc having the rotating center of the male rotor as the center of the arc and a radius R5; and lines (D1-E1), (E1-F1) and (F1-G1) are generated by arcs (D2-E2), (E2-F2) and (F2-G2) of the female rotor tooth profile, respectively. The screw rotors prevent abnormal noise and vibration of the compressor or expander and can be manufactured easily.